Does patient–prosthesis mismatch have a negative impact on outcomes following mitral valve replacement?

Does patient–prosthesis mismatch have a negative impact on outcomes following mitral valve... Abstract A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether patient–prosthesis mismatch (PPM) has a negative impact on patients undergoing mitral valve replacement in terms of postoperative mortality, incidence of postoperative pulmonary hypertension (PH) and higher transmitral gradients. Altogether 103 papers were found using the reported search, 18 of which represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Overall, 8 studies with a total of 4812 patients reported that PPM has a significantly negative impact on long-term mortality, whereas 5 studies with a total of 1558 patients reported no effect on mortality. One study with a total of 2440 patients reported preoperative PH as the risk factor for increased mortality in the presence of moderate or severe PPM. Three studies evaluated the effect of PPM on postoperative PH and reported that PPM was associated with significantly increased postoperative PH. The majority of the studies reported that PPM was associated with higher peak or mean transmitral gradient and systolic pulmonary artery pressure. The results presented in these studies suggest that PPM in patients undergoing mitral valve replacement was associated with increased postoperative mean and peak transmitral gradient and higher postoperative systolic pulmonary artery pressure. PPM may be associated with increased long-term mortality. Severe PPM was directly associated with increased long-term mortality when compared with moderate or no PPM. Evidence suggests that PPM is associated with increased incidence of postoperative PH. Patient–prosthesis mismatch, Mitral valve replacement, Long-term mortality, Outcomes INTRODUCTION A best evidence topic was constructed according to a structured protocol. This is fully described in the ICVTS [1]. THREE-PART QUESTION In [patients undergoing mitral valve replacement] does [patient–prosthesis mismatch] have a negative impact in terms of [postoperative mortality, incidence of postoperative pulmonary hypertension and transmitral gradients]? CLINICAL SCENARIO Mitral valve replacement (MVR) in a 65-year-old female patient with severe mitral stenosis was performed. Having analysed the postoperative echocardiography, the patient was diagnosed with a patient–prosthesis mismatch (PPM). A recent paper published that in patients undergoing aortic valve replacement, a moderate or severe PPM is known to worsen postoperative results, specifically the early and mid-term survival rates [2]. Therefore, you wonder whether PPM following MVR might have a negative impact on the patient’s clinical outcomes and you resolve to search the literature yourself. SEARCH STRATEGY The literature was reviewed by searching Medline from 1950 to July 2017 using PubMed interface: [(Mitral valve) AND (Replacement) AND (Mismatch)]. In addition, similar searches were performed in OVID, EMBASE and Cochrane Central Registry of Controlled Trials. SEARCH OUTCOME A total of 103 papers were found using the reported search. Of these, 18 papers were identified to provide the best available evidence to answer the clinical question. These are presented in Table 1. Table 1: Best evidence papers Author, date, journal and country Study type (level of evidence) Patient group Outcomes Key results Comments Ammannaya et al. (2017), Eur J Cardiothorac Surg, India [3] Retrospective cohort study (level 2b) n = 500 patients PPM: 37.2% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 PH defined as SPAP >40 mmHg Follow-up: 8.15 ± 3.2-years Mortality at 10 years No PPM vs PPM: 18.6% vs 29.2% (P < 0.001) Lower regression of PH was seen in patients with PPM The difference in mortality and freedom from cardiac death remains with propensity matching of the groups EOA measured through CE Mortality at 20 years No PPM vs PPM: 29.9% vs 45.2% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 87.6% vs 76.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 81.2% vs 60.9% (P < 0.001) Incidence of preoperative PH No PPM vs PPM: 81.8% vs 83.3% (P = 0.67) Incidence of postoperative PH No PPM vs PPM: 19.4% vs 66.1% (P < 0.001) Peak PTG No PPM vs PPM: 7.5 ± 3.5 mmHg vs 12.3 ± 4.3 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3.2 ± 1.2 mmHg vs 5.5 ± 1.5 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 30.49 ± 8.2 mmHg vs 42.35 ± 8.4 mmHg (P < 0.001) Hwang et al. (2016), Ann Thorac Surg, Korea [4] Retrospective cohort study (level 2b) n = 760 patients PPM: 19.3% Valve Bioprosthetic: 15.8% Mechanical: 84.2% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 127 months Mortality at 10 years No PPM vs PPM: 14.4% vs 25.1% (P < 0.001) EOA obtained from the literature Propensity score limited due to the small number of patients (n = 60) Mortality at 20 years No PPM vs PPM: 26.6% vs 38.6% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 92.2% vs 80.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 84.7% vs 57.5% (P < 0.001) Borracci et al. (2016), Cardiol J, Argentina [5] Retrospective cohort study (level 2b) n = 136 patients Moderate PPM: 44.1% Severe PPM: 26.4% Valve Bioprosthetic: 43% Mechanical: 57% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Severe PH defined as SPAP >55 mmHg Follow-up: 60 months Mortality at 5 years No PPM vs moderate PPM vs severe PPM: 10.5% vs 6.3% vs 44.1% (P = 0.043) EOA obtained from the literature Mortality at 5 years in patients with severe PH No PPM or moderate PPM vs severe PPM or moderate PPM: 4.9% vs 25.1% (P = 0.016) Aziz et al. (2010), Ann Thorac Surg, USA [6] Retrospective cohort study (level 2b) n = 765 patients Moderate PPM: 37.3% Severe PPM: 13.9% Valve Bioprosthetic: 42% Mechanical: 58% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 58 ± 51 months Mortality at 10 years EOA obtained from the literature No PPM 44% ± 5% Moderate PPM 48% ± 6% Severe PPM 59% ± 9% (P = 0.02) Magne et al. (2007), Circulation, Canada [7] Retrospective cohort study (level 2b) n = 929 patients Moderate PPM: 69.3% Severe PPM: 8.7% Valve Bioprosthetic: 15.1% Mechanical: 84.9% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.3 ± 4.5 years Mortality at 6 years No PPM vs moderate PPM: 10% ± 2% vs 16% ± 1% (P = 0.029) EOA was either measured through CE or obtained from the literature No PPM vs severe PPM: 10% ± 2% vs 26% ± 5% (P = 0.002) Mortality at 12 years No PPM vs moderate PPM: 18% ± 4% vs 24% ± 2% (P = 0.029) No PPM vs severe PPM: 18% ± 4% vs 37% ± 7% (P = 0.002) Peak PTG No PPM 8 ± 2.4 mmHg Moderate PPM 9.8 ± 3.3 mmHg Severe PPM 13.4 ± 4.6 mmHg (P < 0.001) Mean PTG No PPM 2.6 ± 1.0 mmHg Moderate PPM 3.9 ± 1.3 mmHg Severe PPM 6.0 ± .6 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs moderate PPM vs severe PPM: 38 ± 9 mmHg vs 41 ± 8 mmHg vs 49 ± 12 mmHg (P < 0.001) Sato et al. (2014), Circ J, Japan [8] Retrospective cohort study (level 2b) n = 142 patients PPM: 42.3% Valve Bioprosthetic: 22.5% Mechanical: 77.5% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 7.0 ± 3.5 years Mortality PPM was associated with increased long-term mortality (P < 0.05) EOA obtained from the literature Mean PTG No PPM vs PPM: 3.7 ± 1.2 mmHg vs 4.8 ± 1.5 mmHg (P < 0.001) Bouchard et al. (2010), Can J Cardiol, Canada [9] Retrospective cohort study (level 2b) n = 714 patients PPM: 10.3% Valve Mechanical: 100% PPM defined as iEOA <1.3 cm2/m2 Follow-up: 1871 ± 1178 days Mortality at 5 years No PPM vs PPM: 16.4% ± 1.7% vs 24.8% ± 6.2% (P = 0.007) EOA obtained from the literature Mortality at 10 years No PPM vs PPM: 32.6% ± 4.2% vs 46.1% ± 16.3% (P = 0.007) Lam et al. (2007), J Thorac Cardiovasc Surg, Canada [10] Retrospective cohort study (level 2b) n = 884 patients PPM: 31.6% Valve Bioprosthetic: 25.7% Mechanical: 74.3% PPM defined as iEOA ≤1.25 cm2/m2 Follow-up: 5.1 ± 4.1 years Mortality at 5 years No PPM vs PPM: 14% vs 22% (P = 0.05) EOA obtained from the literature or by the manufacturer Mortality at 10 years No PPM vs PPM: 25% vs 35% (P = 0.05) Jamieson et al. (2009), Ann Thorac Surg, Canada [11] Retrospective cohort study (level 2b) n = 2440 patients Moderate PPM: 69.5% Severe PPM: 16.3% Valve Bioprosthetic: 55.6% Mechanical: 44.4% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.1 ± 4.6 years Early mortality No PPM vs moderate PPM vs severe PPM: 5.5% vs 6.3% vs 8.5% (P = 0.182) EOA obtained from the literature or by echocardiography Late mortality No PPM vs moderate PPM vs severe PPM: 36.8% vs 32.8% vs 22.6% (P = NS) Incidence of preoperative PH No PPM vs moderate PPM vs severe PPM: 34.5% vs 37.4% vs 56.9% (P < 0.0001) Angeloni et al. (2013), Int J Cardiol, Italy [12] Retrospective cohort study (level 2b) n = 210 patients PPM: 42% Valve Bioprosthetic: 35.8% Mechanical: 64.2% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Follow-up: 27 months Mortality at follow-up No PPM vs PPM: 12.3% vs 12.5% (P = 0.83) EOA measured through CE Incidence of preoperative PH No PPM vs PPM: 70% vs 72% (P = 0.47) Incidence of PH at follow-up No PPM vs PPM: 24% vs 61% (P < 0.0001) Mean PTG No PPM vs PPM: 3.2 ± 2.5 mmHg vs 4.7 ± 1.1 mmHg (P < 0.0001) Mean postoperative SPAP No PPM vs PPM: 31 ± 6 mmHg vs 41 ± 9 mmHg (P < 0.0001) Pisano et al. (2016), J Heart Valve Dis, Italy [13] Retrospective cohort study (level 2b) n = 46 patients PPM: 25% Valve Bioprosthesis: 19.57% Mechanical: 80.43% PPM defined as iEOA <1.2 cm2/m2 Mean follow-up: 6.9 ± 1.8 years Mortality at follow-up No PPM vs PPM: 0% vs 0% EOA measured through CE Shi et al. (2011), Heart, Australia [14] Retrospective cohort study (level 2b) n = 1006 patients Moderate PPM: 52.8% Severe PPM: 13.2% Valve Bioprosthetic: 38% Mechanical: 62% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 7 years Mortality at 7 years No PPM vs moderate PPM vs severe PPM: 28% ± 4% vs 24% ± 2% vs 31% ± 10.3% (P = 0.76) EOA obtained from the literature Matsuura et al. (2011), Ann Thorac Cardiovasc Surg, Japan [15] Retrospective cohort study (level 2b) n = 212 patients PPM: 59% Valve Bioprosthetic: 34.9% Mechanical: 65.1% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 4.5 ± 8.4 years Late mortality No PPM vs PPM: 7% vs 9.6% (P = 0.1) EOA obtained from the literature or by echocardiography Peak PTG No PPM vs PPM: 9.8 ± 4.5 mmHg vs 11.9 ± 6.2 mmHg (P = 0.042) Mean PTG No PPM vs PPM: 3.6 ± 2.1 mmHg vs 4.0 ± 1.9 mmHg (P = 0.21) Sakamoto et al. (2010), Ann Thorac Cardiovasc Surg, Japan [16] Retrospective cohort study (level 2b) n = 84 patients PPM: 29.7% Valve Bioprosthetic: 10.7% Mechanical: 89.3% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 8.5 ± 3.9 years Freedom of cardiac death at: No PPM vs PPM: EOA measured through echocardiography 5 years 96% vs 100% 10 years 93% vs 95% 14 years 82% vs 95% (P > 0.05) Cho et al. (2016), Yonsei Med J, Korea [17] Retrospective cohort study (level 2b) n = 166 patients Moderate PPM: 48% Severe PPM: 14% Valve Bioprosthetic: 22% Mechanical: 78% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 16 months Mean PTG No PPM vs PPM: 3.2 ± 1.1 mmHg vs 3.7 ± 1.2 mmHg (P < 0.021) In both groups, transmitral gradients remained below mild in terms of stenosis Mean postoperative SPAP No PPM vs moderate PPM: 25 ± 6 mmHg vs 28 ± 6 mmHg (P < 0.007) EOA obtained from the literature, manufacturer or by echocardiography Moderate PPM vs severe PPM: 28 ± 6 mmHg vs 33 ± 11 mmHg (P < 0.037) Cao et al. (2015), Med Sci Monit, China [18] Retrospective cohort study (level 2b) n = 493 patients PPM: 31.8% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 3 years Mean PTG No PPM vs PPM: 14.89 ± 5.77 vs 25.34 ± 6.35 (P < 0.01) Severe postoperative mitral stenosis at follow-up even in those patients with no PPM EOA measured through CE Mean postoperative SPAP No PPM vs PPM: 43.17 ± 12.17 mmHg vs 53.29 ± 10.63 mmHg (P < 0.01) Li et al. (2005), J Am Coll Cardiol, Canada [19] Retrospective cohort study (level 2b) n = 56 patients PPM: 71.4% Valve Bioprosthetic: 16% Mechanical: 84% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Incidence of preoperative PH No PPM vs PPM: 69% vs 66% (P > 0.05) Lower regression of PH was observed in patients with PPM EOA measured through CE Incidence of postoperative PH No PPM vs PPM: 19% vs 68% (P = 0.001) Peak PTG No PPM vs PPM: 8 ± 2 mmHg vs 12 ± 4 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3 ± 1 mmHg vs 4 ± 2 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 46 ± 8 mmHg (P < 0.001) Ozyalcin et al. (2016), J Heart Valve Dis, Turkey [20] Retrospective cohort study (level 2b) n = 128 patients PPM: 35% Valve Mechanical: 100% PPM defined as iEOA <1.19 cm2/m2 Follow-up: 46 ± 9 months Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 45 ± 7 mmHg (P < 0.0001) EOA measured through CE Author, date, journal and country Study type (level of evidence) Patient group Outcomes Key results Comments Ammannaya et al. (2017), Eur J Cardiothorac Surg, India [3] Retrospective cohort study (level 2b) n = 500 patients PPM: 37.2% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 PH defined as SPAP >40 mmHg Follow-up: 8.15 ± 3.2-years Mortality at 10 years No PPM vs PPM: 18.6% vs 29.2% (P < 0.001) Lower regression of PH was seen in patients with PPM The difference in mortality and freedom from cardiac death remains with propensity matching of the groups EOA measured through CE Mortality at 20 years No PPM vs PPM: 29.9% vs 45.2% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 87.6% vs 76.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 81.2% vs 60.9% (P < 0.001) Incidence of preoperative PH No PPM vs PPM: 81.8% vs 83.3% (P = 0.67) Incidence of postoperative PH No PPM vs PPM: 19.4% vs 66.1% (P < 0.001) Peak PTG No PPM vs PPM: 7.5 ± 3.5 mmHg vs 12.3 ± 4.3 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3.2 ± 1.2 mmHg vs 5.5 ± 1.5 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 30.49 ± 8.2 mmHg vs 42.35 ± 8.4 mmHg (P < 0.001) Hwang et al. (2016), Ann Thorac Surg, Korea [4] Retrospective cohort study (level 2b) n = 760 patients PPM: 19.3% Valve Bioprosthetic: 15.8% Mechanical: 84.2% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 127 months Mortality at 10 years No PPM vs PPM: 14.4% vs 25.1% (P < 0.001) EOA obtained from the literature Propensity score limited due to the small number of patients (n = 60) Mortality at 20 years No PPM vs PPM: 26.6% vs 38.6% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 92.2% vs 80.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 84.7% vs 57.5% (P < 0.001) Borracci et al. (2016), Cardiol J, Argentina [5] Retrospective cohort study (level 2b) n = 136 patients Moderate PPM: 44.1% Severe PPM: 26.4% Valve Bioprosthetic: 43% Mechanical: 57% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Severe PH defined as SPAP >55 mmHg Follow-up: 60 months Mortality at 5 years No PPM vs moderate PPM vs severe PPM: 10.5% vs 6.3% vs 44.1% (P = 0.043) EOA obtained from the literature Mortality at 5 years in patients with severe PH No PPM or moderate PPM vs severe PPM or moderate PPM: 4.9% vs 25.1% (P = 0.016) Aziz et al. (2010), Ann Thorac Surg, USA [6] Retrospective cohort study (level 2b) n = 765 patients Moderate PPM: 37.3% Severe PPM: 13.9% Valve Bioprosthetic: 42% Mechanical: 58% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 58 ± 51 months Mortality at 10 years EOA obtained from the literature No PPM 44% ± 5% Moderate PPM 48% ± 6% Severe PPM 59% ± 9% (P = 0.02) Magne et al. (2007), Circulation, Canada [7] Retrospective cohort study (level 2b) n = 929 patients Moderate PPM: 69.3% Severe PPM: 8.7% Valve Bioprosthetic: 15.1% Mechanical: 84.9% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.3 ± 4.5 years Mortality at 6 years No PPM vs moderate PPM: 10% ± 2% vs 16% ± 1% (P = 0.029) EOA was either measured through CE or obtained from the literature No PPM vs severe PPM: 10% ± 2% vs 26% ± 5% (P = 0.002) Mortality at 12 years No PPM vs moderate PPM: 18% ± 4% vs 24% ± 2% (P = 0.029) No PPM vs severe PPM: 18% ± 4% vs 37% ± 7% (P = 0.002) Peak PTG No PPM 8 ± 2.4 mmHg Moderate PPM 9.8 ± 3.3 mmHg Severe PPM 13.4 ± 4.6 mmHg (P < 0.001) Mean PTG No PPM 2.6 ± 1.0 mmHg Moderate PPM 3.9 ± 1.3 mmHg Severe PPM 6.0 ± .6 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs moderate PPM vs severe PPM: 38 ± 9 mmHg vs 41 ± 8 mmHg vs 49 ± 12 mmHg (P < 0.001) Sato et al. (2014), Circ J, Japan [8] Retrospective cohort study (level 2b) n = 142 patients PPM: 42.3% Valve Bioprosthetic: 22.5% Mechanical: 77.5% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 7.0 ± 3.5 years Mortality PPM was associated with increased long-term mortality (P < 0.05) EOA obtained from the literature Mean PTG No PPM vs PPM: 3.7 ± 1.2 mmHg vs 4.8 ± 1.5 mmHg (P < 0.001) Bouchard et al. (2010), Can J Cardiol, Canada [9] Retrospective cohort study (level 2b) n = 714 patients PPM: 10.3% Valve Mechanical: 100% PPM defined as iEOA <1.3 cm2/m2 Follow-up: 1871 ± 1178 days Mortality at 5 years No PPM vs PPM: 16.4% ± 1.7% vs 24.8% ± 6.2% (P = 0.007) EOA obtained from the literature Mortality at 10 years No PPM vs PPM: 32.6% ± 4.2% vs 46.1% ± 16.3% (P = 0.007) Lam et al. (2007), J Thorac Cardiovasc Surg, Canada [10] Retrospective cohort study (level 2b) n = 884 patients PPM: 31.6% Valve Bioprosthetic: 25.7% Mechanical: 74.3% PPM defined as iEOA ≤1.25 cm2/m2 Follow-up: 5.1 ± 4.1 years Mortality at 5 years No PPM vs PPM: 14% vs 22% (P = 0.05) EOA obtained from the literature or by the manufacturer Mortality at 10 years No PPM vs PPM: 25% vs 35% (P = 0.05) Jamieson et al. (2009), Ann Thorac Surg, Canada [11] Retrospective cohort study (level 2b) n = 2440 patients Moderate PPM: 69.5% Severe PPM: 16.3% Valve Bioprosthetic: 55.6% Mechanical: 44.4% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.1 ± 4.6 years Early mortality No PPM vs moderate PPM vs severe PPM: 5.5% vs 6.3% vs 8.5% (P = 0.182) EOA obtained from the literature or by echocardiography Late mortality No PPM vs moderate PPM vs severe PPM: 36.8% vs 32.8% vs 22.6% (P = NS) Incidence of preoperative PH No PPM vs moderate PPM vs severe PPM: 34.5% vs 37.4% vs 56.9% (P < 0.0001) Angeloni et al. (2013), Int J Cardiol, Italy [12] Retrospective cohort study (level 2b) n = 210 patients PPM: 42% Valve Bioprosthetic: 35.8% Mechanical: 64.2% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Follow-up: 27 months Mortality at follow-up No PPM vs PPM: 12.3% vs 12.5% (P = 0.83) EOA measured through CE Incidence of preoperative PH No PPM vs PPM: 70% vs 72% (P = 0.47) Incidence of PH at follow-up No PPM vs PPM: 24% vs 61% (P < 0.0001) Mean PTG No PPM vs PPM: 3.2 ± 2.5 mmHg vs 4.7 ± 1.1 mmHg (P < 0.0001) Mean postoperative SPAP No PPM vs PPM: 31 ± 6 mmHg vs 41 ± 9 mmHg (P < 0.0001) Pisano et al. (2016), J Heart Valve Dis, Italy [13] Retrospective cohort study (level 2b) n = 46 patients PPM: 25% Valve Bioprosthesis: 19.57% Mechanical: 80.43% PPM defined as iEOA <1.2 cm2/m2 Mean follow-up: 6.9 ± 1.8 years Mortality at follow-up No PPM vs PPM: 0% vs 0% EOA measured through CE Shi et al. (2011), Heart, Australia [14] Retrospective cohort study (level 2b) n = 1006 patients Moderate PPM: 52.8% Severe PPM: 13.2% Valve Bioprosthetic: 38% Mechanical: 62% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 7 years Mortality at 7 years No PPM vs moderate PPM vs severe PPM: 28% ± 4% vs 24% ± 2% vs 31% ± 10.3% (P = 0.76) EOA obtained from the literature Matsuura et al. (2011), Ann Thorac Cardiovasc Surg, Japan [15] Retrospective cohort study (level 2b) n = 212 patients PPM: 59% Valve Bioprosthetic: 34.9% Mechanical: 65.1% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 4.5 ± 8.4 years Late mortality No PPM vs PPM: 7% vs 9.6% (P = 0.1) EOA obtained from the literature or by echocardiography Peak PTG No PPM vs PPM: 9.8 ± 4.5 mmHg vs 11.9 ± 6.2 mmHg (P = 0.042) Mean PTG No PPM vs PPM: 3.6 ± 2.1 mmHg vs 4.0 ± 1.9 mmHg (P = 0.21) Sakamoto et al. (2010), Ann Thorac Cardiovasc Surg, Japan [16] Retrospective cohort study (level 2b) n = 84 patients PPM: 29.7% Valve Bioprosthetic: 10.7% Mechanical: 89.3% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 8.5 ± 3.9 years Freedom of cardiac death at: No PPM vs PPM: EOA measured through echocardiography 5 years 96% vs 100% 10 years 93% vs 95% 14 years 82% vs 95% (P > 0.05) Cho et al. (2016), Yonsei Med J, Korea [17] Retrospective cohort study (level 2b) n = 166 patients Moderate PPM: 48% Severe PPM: 14% Valve Bioprosthetic: 22% Mechanical: 78% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 16 months Mean PTG No PPM vs PPM: 3.2 ± 1.1 mmHg vs 3.7 ± 1.2 mmHg (P < 0.021) In both groups, transmitral gradients remained below mild in terms of stenosis Mean postoperative SPAP No PPM vs moderate PPM: 25 ± 6 mmHg vs 28 ± 6 mmHg (P < 0.007) EOA obtained from the literature, manufacturer or by echocardiography Moderate PPM vs severe PPM: 28 ± 6 mmHg vs 33 ± 11 mmHg (P < 0.037) Cao et al. (2015), Med Sci Monit, China [18] Retrospective cohort study (level 2b) n = 493 patients PPM: 31.8% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 3 years Mean PTG No PPM vs PPM: 14.89 ± 5.77 vs 25.34 ± 6.35 (P < 0.01) Severe postoperative mitral stenosis at follow-up even in those patients with no PPM EOA measured through CE Mean postoperative SPAP No PPM vs PPM: 43.17 ± 12.17 mmHg vs 53.29 ± 10.63 mmHg (P < 0.01) Li et al. (2005), J Am Coll Cardiol, Canada [19] Retrospective cohort study (level 2b) n = 56 patients PPM: 71.4% Valve Bioprosthetic: 16% Mechanical: 84% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Incidence of preoperative PH No PPM vs PPM: 69% vs 66% (P > 0.05) Lower regression of PH was observed in patients with PPM EOA measured through CE Incidence of postoperative PH No PPM vs PPM: 19% vs 68% (P = 0.001) Peak PTG No PPM vs PPM: 8 ± 2 mmHg vs 12 ± 4 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3 ± 1 mmHg vs 4 ± 2 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 46 ± 8 mmHg (P < 0.001) Ozyalcin et al. (2016), J Heart Valve Dis, Turkey [20] Retrospective cohort study (level 2b) n = 128 patients PPM: 35% Valve Mechanical: 100% PPM defined as iEOA <1.19 cm2/m2 Follow-up: 46 ± 9 months Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 45 ± 7 mmHg (P < 0.0001) EOA measured through CE CE: continuity equation; iEOA: indexed effective orifice area; PH: pulmonary hypertension; PPM: patient–prosthesis mismatch; PTG: postoperative transmitral gradient; SPAP: systolic pulmonary artery pressure. Table 1: Best evidence papers Author, date, journal and country Study type (level of evidence) Patient group Outcomes Key results Comments Ammannaya et al. (2017), Eur J Cardiothorac Surg, India [3] Retrospective cohort study (level 2b) n = 500 patients PPM: 37.2% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 PH defined as SPAP >40 mmHg Follow-up: 8.15 ± 3.2-years Mortality at 10 years No PPM vs PPM: 18.6% vs 29.2% (P < 0.001) Lower regression of PH was seen in patients with PPM The difference in mortality and freedom from cardiac death remains with propensity matching of the groups EOA measured through CE Mortality at 20 years No PPM vs PPM: 29.9% vs 45.2% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 87.6% vs 76.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 81.2% vs 60.9% (P < 0.001) Incidence of preoperative PH No PPM vs PPM: 81.8% vs 83.3% (P = 0.67) Incidence of postoperative PH No PPM vs PPM: 19.4% vs 66.1% (P < 0.001) Peak PTG No PPM vs PPM: 7.5 ± 3.5 mmHg vs 12.3 ± 4.3 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3.2 ± 1.2 mmHg vs 5.5 ± 1.5 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 30.49 ± 8.2 mmHg vs 42.35 ± 8.4 mmHg (P < 0.001) Hwang et al. (2016), Ann Thorac Surg, Korea [4] Retrospective cohort study (level 2b) n = 760 patients PPM: 19.3% Valve Bioprosthetic: 15.8% Mechanical: 84.2% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 127 months Mortality at 10 years No PPM vs PPM: 14.4% vs 25.1% (P < 0.001) EOA obtained from the literature Propensity score limited due to the small number of patients (n = 60) Mortality at 20 years No PPM vs PPM: 26.6% vs 38.6% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 92.2% vs 80.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 84.7% vs 57.5% (P < 0.001) Borracci et al. (2016), Cardiol J, Argentina [5] Retrospective cohort study (level 2b) n = 136 patients Moderate PPM: 44.1% Severe PPM: 26.4% Valve Bioprosthetic: 43% Mechanical: 57% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Severe PH defined as SPAP >55 mmHg Follow-up: 60 months Mortality at 5 years No PPM vs moderate PPM vs severe PPM: 10.5% vs 6.3% vs 44.1% (P = 0.043) EOA obtained from the literature Mortality at 5 years in patients with severe PH No PPM or moderate PPM vs severe PPM or moderate PPM: 4.9% vs 25.1% (P = 0.016) Aziz et al. (2010), Ann Thorac Surg, USA [6] Retrospective cohort study (level 2b) n = 765 patients Moderate PPM: 37.3% Severe PPM: 13.9% Valve Bioprosthetic: 42% Mechanical: 58% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 58 ± 51 months Mortality at 10 years EOA obtained from the literature No PPM 44% ± 5% Moderate PPM 48% ± 6% Severe PPM 59% ± 9% (P = 0.02) Magne et al. (2007), Circulation, Canada [7] Retrospective cohort study (level 2b) n = 929 patients Moderate PPM: 69.3% Severe PPM: 8.7% Valve Bioprosthetic: 15.1% Mechanical: 84.9% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.3 ± 4.5 years Mortality at 6 years No PPM vs moderate PPM: 10% ± 2% vs 16% ± 1% (P = 0.029) EOA was either measured through CE or obtained from the literature No PPM vs severe PPM: 10% ± 2% vs 26% ± 5% (P = 0.002) Mortality at 12 years No PPM vs moderate PPM: 18% ± 4% vs 24% ± 2% (P = 0.029) No PPM vs severe PPM: 18% ± 4% vs 37% ± 7% (P = 0.002) Peak PTG No PPM 8 ± 2.4 mmHg Moderate PPM 9.8 ± 3.3 mmHg Severe PPM 13.4 ± 4.6 mmHg (P < 0.001) Mean PTG No PPM 2.6 ± 1.0 mmHg Moderate PPM 3.9 ± 1.3 mmHg Severe PPM 6.0 ± .6 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs moderate PPM vs severe PPM: 38 ± 9 mmHg vs 41 ± 8 mmHg vs 49 ± 12 mmHg (P < 0.001) Sato et al. (2014), Circ J, Japan [8] Retrospective cohort study (level 2b) n = 142 patients PPM: 42.3% Valve Bioprosthetic: 22.5% Mechanical: 77.5% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 7.0 ± 3.5 years Mortality PPM was associated with increased long-term mortality (P < 0.05) EOA obtained from the literature Mean PTG No PPM vs PPM: 3.7 ± 1.2 mmHg vs 4.8 ± 1.5 mmHg (P < 0.001) Bouchard et al. (2010), Can J Cardiol, Canada [9] Retrospective cohort study (level 2b) n = 714 patients PPM: 10.3% Valve Mechanical: 100% PPM defined as iEOA <1.3 cm2/m2 Follow-up: 1871 ± 1178 days Mortality at 5 years No PPM vs PPM: 16.4% ± 1.7% vs 24.8% ± 6.2% (P = 0.007) EOA obtained from the literature Mortality at 10 years No PPM vs PPM: 32.6% ± 4.2% vs 46.1% ± 16.3% (P = 0.007) Lam et al. (2007), J Thorac Cardiovasc Surg, Canada [10] Retrospective cohort study (level 2b) n = 884 patients PPM: 31.6% Valve Bioprosthetic: 25.7% Mechanical: 74.3% PPM defined as iEOA ≤1.25 cm2/m2 Follow-up: 5.1 ± 4.1 years Mortality at 5 years No PPM vs PPM: 14% vs 22% (P = 0.05) EOA obtained from the literature or by the manufacturer Mortality at 10 years No PPM vs PPM: 25% vs 35% (P = 0.05) Jamieson et al. (2009), Ann Thorac Surg, Canada [11] Retrospective cohort study (level 2b) n = 2440 patients Moderate PPM: 69.5% Severe PPM: 16.3% Valve Bioprosthetic: 55.6% Mechanical: 44.4% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.1 ± 4.6 years Early mortality No PPM vs moderate PPM vs severe PPM: 5.5% vs 6.3% vs 8.5% (P = 0.182) EOA obtained from the literature or by echocardiography Late mortality No PPM vs moderate PPM vs severe PPM: 36.8% vs 32.8% vs 22.6% (P = NS) Incidence of preoperative PH No PPM vs moderate PPM vs severe PPM: 34.5% vs 37.4% vs 56.9% (P < 0.0001) Angeloni et al. (2013), Int J Cardiol, Italy [12] Retrospective cohort study (level 2b) n = 210 patients PPM: 42% Valve Bioprosthetic: 35.8% Mechanical: 64.2% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Follow-up: 27 months Mortality at follow-up No PPM vs PPM: 12.3% vs 12.5% (P = 0.83) EOA measured through CE Incidence of preoperative PH No PPM vs PPM: 70% vs 72% (P = 0.47) Incidence of PH at follow-up No PPM vs PPM: 24% vs 61% (P < 0.0001) Mean PTG No PPM vs PPM: 3.2 ± 2.5 mmHg vs 4.7 ± 1.1 mmHg (P < 0.0001) Mean postoperative SPAP No PPM vs PPM: 31 ± 6 mmHg vs 41 ± 9 mmHg (P < 0.0001) Pisano et al. (2016), J Heart Valve Dis, Italy [13] Retrospective cohort study (level 2b) n = 46 patients PPM: 25% Valve Bioprosthesis: 19.57% Mechanical: 80.43% PPM defined as iEOA <1.2 cm2/m2 Mean follow-up: 6.9 ± 1.8 years Mortality at follow-up No PPM vs PPM: 0% vs 0% EOA measured through CE Shi et al. (2011), Heart, Australia [14] Retrospective cohort study (level 2b) n = 1006 patients Moderate PPM: 52.8% Severe PPM: 13.2% Valve Bioprosthetic: 38% Mechanical: 62% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 7 years Mortality at 7 years No PPM vs moderate PPM vs severe PPM: 28% ± 4% vs 24% ± 2% vs 31% ± 10.3% (P = 0.76) EOA obtained from the literature Matsuura et al. (2011), Ann Thorac Cardiovasc Surg, Japan [15] Retrospective cohort study (level 2b) n = 212 patients PPM: 59% Valve Bioprosthetic: 34.9% Mechanical: 65.1% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 4.5 ± 8.4 years Late mortality No PPM vs PPM: 7% vs 9.6% (P = 0.1) EOA obtained from the literature or by echocardiography Peak PTG No PPM vs PPM: 9.8 ± 4.5 mmHg vs 11.9 ± 6.2 mmHg (P = 0.042) Mean PTG No PPM vs PPM: 3.6 ± 2.1 mmHg vs 4.0 ± 1.9 mmHg (P = 0.21) Sakamoto et al. (2010), Ann Thorac Cardiovasc Surg, Japan [16] Retrospective cohort study (level 2b) n = 84 patients PPM: 29.7% Valve Bioprosthetic: 10.7% Mechanical: 89.3% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 8.5 ± 3.9 years Freedom of cardiac death at: No PPM vs PPM: EOA measured through echocardiography 5 years 96% vs 100% 10 years 93% vs 95% 14 years 82% vs 95% (P > 0.05) Cho et al. (2016), Yonsei Med J, Korea [17] Retrospective cohort study (level 2b) n = 166 patients Moderate PPM: 48% Severe PPM: 14% Valve Bioprosthetic: 22% Mechanical: 78% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 16 months Mean PTG No PPM vs PPM: 3.2 ± 1.1 mmHg vs 3.7 ± 1.2 mmHg (P < 0.021) In both groups, transmitral gradients remained below mild in terms of stenosis Mean postoperative SPAP No PPM vs moderate PPM: 25 ± 6 mmHg vs 28 ± 6 mmHg (P < 0.007) EOA obtained from the literature, manufacturer or by echocardiography Moderate PPM vs severe PPM: 28 ± 6 mmHg vs 33 ± 11 mmHg (P < 0.037) Cao et al. (2015), Med Sci Monit, China [18] Retrospective cohort study (level 2b) n = 493 patients PPM: 31.8% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 3 years Mean PTG No PPM vs PPM: 14.89 ± 5.77 vs 25.34 ± 6.35 (P < 0.01) Severe postoperative mitral stenosis at follow-up even in those patients with no PPM EOA measured through CE Mean postoperative SPAP No PPM vs PPM: 43.17 ± 12.17 mmHg vs 53.29 ± 10.63 mmHg (P < 0.01) Li et al. (2005), J Am Coll Cardiol, Canada [19] Retrospective cohort study (level 2b) n = 56 patients PPM: 71.4% Valve Bioprosthetic: 16% Mechanical: 84% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Incidence of preoperative PH No PPM vs PPM: 69% vs 66% (P > 0.05) Lower regression of PH was observed in patients with PPM EOA measured through CE Incidence of postoperative PH No PPM vs PPM: 19% vs 68% (P = 0.001) Peak PTG No PPM vs PPM: 8 ± 2 mmHg vs 12 ± 4 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3 ± 1 mmHg vs 4 ± 2 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 46 ± 8 mmHg (P < 0.001) Ozyalcin et al. (2016), J Heart Valve Dis, Turkey [20] Retrospective cohort study (level 2b) n = 128 patients PPM: 35% Valve Mechanical: 100% PPM defined as iEOA <1.19 cm2/m2 Follow-up: 46 ± 9 months Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 45 ± 7 mmHg (P < 0.0001) EOA measured through CE Author, date, journal and country Study type (level of evidence) Patient group Outcomes Key results Comments Ammannaya et al. (2017), Eur J Cardiothorac Surg, India [3] Retrospective cohort study (level 2b) n = 500 patients PPM: 37.2% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 PH defined as SPAP >40 mmHg Follow-up: 8.15 ± 3.2-years Mortality at 10 years No PPM vs PPM: 18.6% vs 29.2% (P < 0.001) Lower regression of PH was seen in patients with PPM The difference in mortality and freedom from cardiac death remains with propensity matching of the groups EOA measured through CE Mortality at 20 years No PPM vs PPM: 29.9% vs 45.2% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 87.6% vs 76.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 81.2% vs 60.9% (P < 0.001) Incidence of preoperative PH No PPM vs PPM: 81.8% vs 83.3% (P = 0.67) Incidence of postoperative PH No PPM vs PPM: 19.4% vs 66.1% (P < 0.001) Peak PTG No PPM vs PPM: 7.5 ± 3.5 mmHg vs 12.3 ± 4.3 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3.2 ± 1.2 mmHg vs 5.5 ± 1.5 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 30.49 ± 8.2 mmHg vs 42.35 ± 8.4 mmHg (P < 0.001) Hwang et al. (2016), Ann Thorac Surg, Korea [4] Retrospective cohort study (level 2b) n = 760 patients PPM: 19.3% Valve Bioprosthetic: 15.8% Mechanical: 84.2% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 127 months Mortality at 10 years No PPM vs PPM: 14.4% vs 25.1% (P < 0.001) EOA obtained from the literature Propensity score limited due to the small number of patients (n = 60) Mortality at 20 years No PPM vs PPM: 26.6% vs 38.6% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 92.2% vs 80.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 84.7% vs 57.5% (P < 0.001) Borracci et al. (2016), Cardiol J, Argentina [5] Retrospective cohort study (level 2b) n = 136 patients Moderate PPM: 44.1% Severe PPM: 26.4% Valve Bioprosthetic: 43% Mechanical: 57% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Severe PH defined as SPAP >55 mmHg Follow-up: 60 months Mortality at 5 years No PPM vs moderate PPM vs severe PPM: 10.5% vs 6.3% vs 44.1% (P = 0.043) EOA obtained from the literature Mortality at 5 years in patients with severe PH No PPM or moderate PPM vs severe PPM or moderate PPM: 4.9% vs 25.1% (P = 0.016) Aziz et al. (2010), Ann Thorac Surg, USA [6] Retrospective cohort study (level 2b) n = 765 patients Moderate PPM: 37.3% Severe PPM: 13.9% Valve Bioprosthetic: 42% Mechanical: 58% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 58 ± 51 months Mortality at 10 years EOA obtained from the literature No PPM 44% ± 5% Moderate PPM 48% ± 6% Severe PPM 59% ± 9% (P = 0.02) Magne et al. (2007), Circulation, Canada [7] Retrospective cohort study (level 2b) n = 929 patients Moderate PPM: 69.3% Severe PPM: 8.7% Valve Bioprosthetic: 15.1% Mechanical: 84.9% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.3 ± 4.5 years Mortality at 6 years No PPM vs moderate PPM: 10% ± 2% vs 16% ± 1% (P = 0.029) EOA was either measured through CE or obtained from the literature No PPM vs severe PPM: 10% ± 2% vs 26% ± 5% (P = 0.002) Mortality at 12 years No PPM vs moderate PPM: 18% ± 4% vs 24% ± 2% (P = 0.029) No PPM vs severe PPM: 18% ± 4% vs 37% ± 7% (P = 0.002) Peak PTG No PPM 8 ± 2.4 mmHg Moderate PPM 9.8 ± 3.3 mmHg Severe PPM 13.4 ± 4.6 mmHg (P < 0.001) Mean PTG No PPM 2.6 ± 1.0 mmHg Moderate PPM 3.9 ± 1.3 mmHg Severe PPM 6.0 ± .6 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs moderate PPM vs severe PPM: 38 ± 9 mmHg vs 41 ± 8 mmHg vs 49 ± 12 mmHg (P < 0.001) Sato et al. (2014), Circ J, Japan [8] Retrospective cohort study (level 2b) n = 142 patients PPM: 42.3% Valve Bioprosthetic: 22.5% Mechanical: 77.5% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 7.0 ± 3.5 years Mortality PPM was associated with increased long-term mortality (P < 0.05) EOA obtained from the literature Mean PTG No PPM vs PPM: 3.7 ± 1.2 mmHg vs 4.8 ± 1.5 mmHg (P < 0.001) Bouchard et al. (2010), Can J Cardiol, Canada [9] Retrospective cohort study (level 2b) n = 714 patients PPM: 10.3% Valve Mechanical: 100% PPM defined as iEOA <1.3 cm2/m2 Follow-up: 1871 ± 1178 days Mortality at 5 years No PPM vs PPM: 16.4% ± 1.7% vs 24.8% ± 6.2% (P = 0.007) EOA obtained from the literature Mortality at 10 years No PPM vs PPM: 32.6% ± 4.2% vs 46.1% ± 16.3% (P = 0.007) Lam et al. (2007), J Thorac Cardiovasc Surg, Canada [10] Retrospective cohort study (level 2b) n = 884 patients PPM: 31.6% Valve Bioprosthetic: 25.7% Mechanical: 74.3% PPM defined as iEOA ≤1.25 cm2/m2 Follow-up: 5.1 ± 4.1 years Mortality at 5 years No PPM vs PPM: 14% vs 22% (P = 0.05) EOA obtained from the literature or by the manufacturer Mortality at 10 years No PPM vs PPM: 25% vs 35% (P = 0.05) Jamieson et al. (2009), Ann Thorac Surg, Canada [11] Retrospective cohort study (level 2b) n = 2440 patients Moderate PPM: 69.5% Severe PPM: 16.3% Valve Bioprosthetic: 55.6% Mechanical: 44.4% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.1 ± 4.6 years Early mortality No PPM vs moderate PPM vs severe PPM: 5.5% vs 6.3% vs 8.5% (P = 0.182) EOA obtained from the literature or by echocardiography Late mortality No PPM vs moderate PPM vs severe PPM: 36.8% vs 32.8% vs 22.6% (P = NS) Incidence of preoperative PH No PPM vs moderate PPM vs severe PPM: 34.5% vs 37.4% vs 56.9% (P < 0.0001) Angeloni et al. (2013), Int J Cardiol, Italy [12] Retrospective cohort study (level 2b) n = 210 patients PPM: 42% Valve Bioprosthetic: 35.8% Mechanical: 64.2% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Follow-up: 27 months Mortality at follow-up No PPM vs PPM: 12.3% vs 12.5% (P = 0.83) EOA measured through CE Incidence of preoperative PH No PPM vs PPM: 70% vs 72% (P = 0.47) Incidence of PH at follow-up No PPM vs PPM: 24% vs 61% (P < 0.0001) Mean PTG No PPM vs PPM: 3.2 ± 2.5 mmHg vs 4.7 ± 1.1 mmHg (P < 0.0001) Mean postoperative SPAP No PPM vs PPM: 31 ± 6 mmHg vs 41 ± 9 mmHg (P < 0.0001) Pisano et al. (2016), J Heart Valve Dis, Italy [13] Retrospective cohort study (level 2b) n = 46 patients PPM: 25% Valve Bioprosthesis: 19.57% Mechanical: 80.43% PPM defined as iEOA <1.2 cm2/m2 Mean follow-up: 6.9 ± 1.8 years Mortality at follow-up No PPM vs PPM: 0% vs 0% EOA measured through CE Shi et al. (2011), Heart, Australia [14] Retrospective cohort study (level 2b) n = 1006 patients Moderate PPM: 52.8% Severe PPM: 13.2% Valve Bioprosthetic: 38% Mechanical: 62% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 7 years Mortality at 7 years No PPM vs moderate PPM vs severe PPM: 28% ± 4% vs 24% ± 2% vs 31% ± 10.3% (P = 0.76) EOA obtained from the literature Matsuura et al. (2011), Ann Thorac Cardiovasc Surg, Japan [15] Retrospective cohort study (level 2b) n = 212 patients PPM: 59% Valve Bioprosthetic: 34.9% Mechanical: 65.1% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 4.5 ± 8.4 years Late mortality No PPM vs PPM: 7% vs 9.6% (P = 0.1) EOA obtained from the literature or by echocardiography Peak PTG No PPM vs PPM: 9.8 ± 4.5 mmHg vs 11.9 ± 6.2 mmHg (P = 0.042) Mean PTG No PPM vs PPM: 3.6 ± 2.1 mmHg vs 4.0 ± 1.9 mmHg (P = 0.21) Sakamoto et al. (2010), Ann Thorac Cardiovasc Surg, Japan [16] Retrospective cohort study (level 2b) n = 84 patients PPM: 29.7% Valve Bioprosthetic: 10.7% Mechanical: 89.3% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 8.5 ± 3.9 years Freedom of cardiac death at: No PPM vs PPM: EOA measured through echocardiography 5 years 96% vs 100% 10 years 93% vs 95% 14 years 82% vs 95% (P > 0.05) Cho et al. (2016), Yonsei Med J, Korea [17] Retrospective cohort study (level 2b) n = 166 patients Moderate PPM: 48% Severe PPM: 14% Valve Bioprosthetic: 22% Mechanical: 78% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 16 months Mean PTG No PPM vs PPM: 3.2 ± 1.1 mmHg vs 3.7 ± 1.2 mmHg (P < 0.021) In both groups, transmitral gradients remained below mild in terms of stenosis Mean postoperative SPAP No PPM vs moderate PPM: 25 ± 6 mmHg vs 28 ± 6 mmHg (P < 0.007) EOA obtained from the literature, manufacturer or by echocardiography Moderate PPM vs severe PPM: 28 ± 6 mmHg vs 33 ± 11 mmHg (P < 0.037) Cao et al. (2015), Med Sci Monit, China [18] Retrospective cohort study (level 2b) n = 493 patients PPM: 31.8% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 3 years Mean PTG No PPM vs PPM: 14.89 ± 5.77 vs 25.34 ± 6.35 (P < 0.01) Severe postoperative mitral stenosis at follow-up even in those patients with no PPM EOA measured through CE Mean postoperative SPAP No PPM vs PPM: 43.17 ± 12.17 mmHg vs 53.29 ± 10.63 mmHg (P < 0.01) Li et al. (2005), J Am Coll Cardiol, Canada [19] Retrospective cohort study (level 2b) n = 56 patients PPM: 71.4% Valve Bioprosthetic: 16% Mechanical: 84% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Incidence of preoperative PH No PPM vs PPM: 69% vs 66% (P > 0.05) Lower regression of PH was observed in patients with PPM EOA measured through CE Incidence of postoperative PH No PPM vs PPM: 19% vs 68% (P = 0.001) Peak PTG No PPM vs PPM: 8 ± 2 mmHg vs 12 ± 4 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3 ± 1 mmHg vs 4 ± 2 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 46 ± 8 mmHg (P < 0.001) Ozyalcin et al. (2016), J Heart Valve Dis, Turkey [20] Retrospective cohort study (level 2b) n = 128 patients PPM: 35% Valve Mechanical: 100% PPM defined as iEOA <1.19 cm2/m2 Follow-up: 46 ± 9 months Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 45 ± 7 mmHg (P < 0.0001) EOA measured through CE CE: continuity equation; iEOA: indexed effective orifice area; PH: pulmonary hypertension; PPM: patient–prosthesis mismatch; PTG: postoperative transmitral gradient; SPAP: systolic pulmonary artery pressure. RESULTS Ammannaya et al. [3] and Hwang et al. [4] showed that PPM was associated with a significant increase in long-term mortality and reduced freedom from cardiac death at 10 and 20 years following surgery when compared with patients with no PPM. In both studies, the difference in mortality and in freedom from cardiac death remained with propensity matching of the groups. Additionally, Hwang et al. [4] showed that PPM was associated with a significantly higher risk of death [hazard ratio (HR) 1.681, 95% confidence interval (CI) 1.139–2.482; P = 0.009] and a significantly poorer freedom from cardiac death (HR 1.673; 95% CI 1.012–2.765; P = 0.045). However, Ammannaya et al. [3] showed that PPM was associated with a significant increase in mean, peak transmitral gradients, postoperative systolic pulmonary artery pressure (SPAP) and increased incidence of postoperative PH. Borracci et al. [5] showed that severe PPM was associated with increased mortality in comparison with patients with no PPM or moderate PPM over the period of 5-year long follow-up (44.1% vs 10.5% vs 6.3%, P = 0.043, respectively). Also, the authors reported that the impact of severe PPM on mortality was even more pronounced when it was associated with severe postoperative PH. Aziz et al. [6] demonstrated that PPM was associated with a significant increase in long-term mortality when compared with patients with no PPM. Severe PPM, when compared with moderate PPM or no PPM, was associated with higher long-term mortality (59% ± 9% vs 48% ± 6% vs 44% ± 5%, P = 0.02). After stratifying by both age and the implanted valve type, although PPM did not impact long-term survival in younger patients (<65 years) after bioprosthetic MVR (P = 0.26), PPM impaired long-term survival in older bioprosthetic recipients (≥65 years; P = 0.05). On the other hand, moderate or severe PPM tended to impact long-term survival negatively after mechanical MVR in both age groups (<65 years P = 0.06 and ≥65 years P = 0.07). Magne et al. [7] studied the effect of PPM on both mean and peak transmitral gradient and postoperative SPAP and mortality. They reported that PPM was associated with significantly increased mortality over the period of 6 and 12 years following surgery, with a significant increase in peak and mean transmitral gradient as well as mean postoperative SPAP. A subgroup analysis showed that severe PPM was associated with worse outcomes when compared with moderate PPM. Additionally, severe PPM was found to be an independent predictor of mortality following MVR (HR 3.2, 95% CI 1.5–6.8; P = 0.003). Sato et al. [8], Bouchard et al. [9] and Lam et al. [10] showed that PPM was associated with increased long-term mortality when compared with patients with no PPM. In contrast, Jamieson et al. [11] showed that PPM was not associated with increased early and long-term mortality. However, preoperative PH, which is not an uncommon condition in patients undergoing MVR in the presence of moderate or severe PPM, was predictive of overall survival (Moderate PPM: HR 1.6, 95% CI 1.1–2.4; P = 0.02 and Severe PPM: HR 1.8, 95% CI 1.1–2.9; P = 0.03). Angeloni et al. [12] reported that there was no association between PPM and worse survival. The authors reported that PPM was associated with higher postoperative transmitral gradient and postoperative SPAP when compared to patients with no PPM. Incidence of PH remained increased at follow-up in patients with PPM (61% vs 24%, P < 0.0001). Pisano et al. [13], Shi et al. [14] and Matsuura et al. [15] showed that PPM was not associated with higher long-term mortality when compared to patients with no PPM. Sakamoto et al. [16] found no difference in the freedom from cardiac death between patients with no PPM and PPM (P > 0.05). Cho et al. [17], Cao et al. [18] and Li et al. [19] showed that PPM was associated with an increase in mean transmitral gradient and SPAP, also found by Ozyalcin et al. [20]. In addition, Li et al. [19] showed that PPM was also associated with increased incidence of postoperative PH. Overall, 8 studies with a total of 4812 patients showed that PPM has a significantly negative impact on long-term mortality, whereas 5 studies with a total of 1558 patients showed no effect on mortality. One study with a total of 2440 patients showed preoperative PH as the risk factor for increased mortality in the presence of moderate or severe PPM. Three studies with a total of 766 patients evaluated the effect of PPM on postoperative PH and showed that PPM was associated with significantly increased postoperative PH. The majority of the studies showed that PPM was associated with higher peak or mean transmitral gradient and SPAP. CLINICAL BOTTOM LINE PPM in patients undergoing MVR is associated with increased postoperative mean and peak transmitral gradient and higher postoperative SPAP. PPM may be associated with increased long-term mortality. Severe PPM is directly associated with increased long-term mortality when compared with moderate or no PPM. Evidence suggests that PPM is associated with increased incidence of postoperative PH. Conflict of interest: none declared. REFERENCES 1 Dunning J , Prendergast B , Mackway-Jones K. Towards evidence-based medicine in cardiothoracic surgery: best BETS . Interact CardioVasc Thorac Surg 2003 ; 2 : 405 – 9 . Google Scholar CrossRef Search ADS PubMed 2 Urso S , Sadaba R , Aldamiz-Echevarria G. Is patient-prosthesis mismatch an independent risk factor for early and mid-term overall mortality in adult patients undergoing aortic valve replacement? Interact CardioVasc Thorac Surg 2000 ; 9 : 510 – 8 . Google Scholar CrossRef Search ADS 3 Ammannaya GKK , Mishra P , Khandekar JV , Mohapatra CKR , Seth HS , Raut C et al. . Effect of prosthesis patient mismatch in mitral position on pulmonary hypertension . Eur J Cardiothorac Surg 2017 ; 52 : 1168 – 74 . Google Scholar CrossRef Search ADS PubMed 4 Hwang HY , Kim YH , Kim KH , Kim KB , Ahn H. Patient-prosthesis mismatch after mitral valve replacement: a propensity score analysis . Ann Thorac Surg 2016 ; 101 : 1796 – 802 . Google Scholar CrossRef Search ADS PubMed 5 Borracci RA , Rubio M , Sestito ML , Ingino CA , Barrero C , Rapallo CA. Incidence of prosthesis-patient mismatch in patients receiving mitral Biocor® porcine prosthetic valves . Cardiol J 2016 ; 23 : 178 – 83 . Google Scholar CrossRef Search ADS PubMed 6 Aziz A , Lawton JS , Maniar HS , Pasque MK , Damiano RJ Jr , Moon MR. Factors affecting survival after mitral valve replacement in patients with prosthesis-patient mismatch . Ann Thorac Surg 2010 ; 90 : 1202 – 10 . Google Scholar CrossRef Search ADS PubMed 7 Magne J , Mathieu P , Dumesnil JG , Tanné D , Dagenais F , Doyle D et al. . Impact of prosthesis-patient mismatch on survival after mitral valve replacement . Circulation 2007 ; 115 : 1417 – 25 . Google Scholar CrossRef Search ADS PubMed 8 Sato S , Fujita T , Shimahara Y , Hata H , Kobayashi J. Impact of prosthesis-patient mismatch on late recurrence of atrial fibrillation after cryomaze procedure with mitral valve replacement . Circ J 2014 ; 78 : 1908 – 14 . Google Scholar CrossRef Search ADS PubMed 9 Bouchard D , Vanden Eynden F , Demers P , Perrault LP , Carrier M , Cartier R et al. . Patient-prosthesis mismatch in the mitral position affects midterm survival and functional status . Can J Cardiol 2010 ; 26 : 532 – 6 . Google Scholar CrossRef Search ADS PubMed 10 Lam BK , Chan V , Hendry P , Ruel M , Masters R , Bedard P et al. . The impact of patient-prosthesis mismatch on late outcomes after mitral valve replacement . J Thorac Cardiovasc Surg 2007 ; 133 : 1464 – 73 . Google Scholar CrossRef Search ADS PubMed 11 Jamieson WR , Germann E , Ye J , Chan F , Cheung A , MacNab JS et al. . Effect of prosthesis-patient mismatch on long-term survival with mitral valve replacement: assessment to 15 years . Ann Thorac Surg 2009 ; 87 : 1135 – 41 . Google Scholar CrossRef Search ADS PubMed 12 Angeloni E , Melina G , Benedetto U , Roscitano A , Refice S , Quarto C et al. . Impact of prosthesis-patient mismatch on tricuspid valve regurgitation and pulmonary hypertension following mitral valve replacement . Int J Cardiol 2013 ; 168 : 4150 – 4 . Google Scholar CrossRef Search ADS PubMed 13 Pisano C , Balistreri CR , Triolo OF , Franchino R , Allegra A , Capuccio V et al. . Impact of prosthesis-patient mismatch after mitral valve replacement . J Heart Valve Dis 2016 ; 25 : 39 – 45 . Google Scholar PubMed 14 Shi WY , Yap CH , Hayward PA , Dinh DT , Reid CM , Shardey GC et al. . Impact of prosthesis–patient mismatch after mitral valve replacement: a multicentre analysis of early outcomes and mid-term survival . Heart 2011 ; 97 : 1074 – 81 . Google Scholar CrossRef Search ADS PubMed 15 Matsuura K , Mogi K , Aoki C , Takahara Y. Prosthesis-patient mismatch after mitral valve replacement stratified by referred and measured effective valve area . Ann Thorac Cardiovasc Surg 2011 ; 17 : 153 – 9 . Google Scholar CrossRef Search ADS PubMed 16 Sakamoto H , Watanabe Y. Does patient-prosthesis mismatch affect long-term results after mitral valve replacement? Ann Thorac Cardiovasc Surg 2010 ; 16 : 163 – 7 . Google Scholar PubMed 17 Cho IJ , Hong GR , Lee SH , Lee S , Chang BC , Shim CY et al. . Prosthesis-patient mismatch after mitral valve replacement: comparison of different methods of effective orifice area calculation . Yonsei Med J 2016 ; 57 : 328 – 36 . Google Scholar CrossRef Search ADS PubMed 18 Cao H , Qiu Z , Chen L , Chen D , Chen Q. Star GK bileaflet mechanical valve prosthesis-patient mismatch after mitral valve replacement: a Chinese multicenter clinical study . Med Sci Monit 2015 ; 21 : 2542 – 6 . Google Scholar CrossRef Search ADS PubMed 19 Li M , Dumesnil JG , Mathieu P , Pibarot P. Impact of valve prosthesis-patient mismatch on pulmonary arterial pressure after mitral valve replacement . J Am Coll Cardiol 2005 ; 45 : 1034 – 40 . Google Scholar CrossRef Search ADS PubMed 20 Ozyalcin S , Vural KM , Colak A. Mitral patient-prosthesis mismatch predicts suboptimal hemodynamic recovery after mitral valve replacement . J Heart Valve Dis 2016 ; 25 : 589 – 95 . Google Scholar PubMed © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Interactive CardioVascular and Thoracic Surgery Oxford University Press

Does patient–prosthesis mismatch have a negative impact on outcomes following mitral valve replacement?

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Oxford University Press
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© The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
ISSN
1569-9293
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1569-9285
D.O.I.
10.1093/icvts/ivx426
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Abstract

Abstract A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether patient–prosthesis mismatch (PPM) has a negative impact on patients undergoing mitral valve replacement in terms of postoperative mortality, incidence of postoperative pulmonary hypertension (PH) and higher transmitral gradients. Altogether 103 papers were found using the reported search, 18 of which represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Overall, 8 studies with a total of 4812 patients reported that PPM has a significantly negative impact on long-term mortality, whereas 5 studies with a total of 1558 patients reported no effect on mortality. One study with a total of 2440 patients reported preoperative PH as the risk factor for increased mortality in the presence of moderate or severe PPM. Three studies evaluated the effect of PPM on postoperative PH and reported that PPM was associated with significantly increased postoperative PH. The majority of the studies reported that PPM was associated with higher peak or mean transmitral gradient and systolic pulmonary artery pressure. The results presented in these studies suggest that PPM in patients undergoing mitral valve replacement was associated with increased postoperative mean and peak transmitral gradient and higher postoperative systolic pulmonary artery pressure. PPM may be associated with increased long-term mortality. Severe PPM was directly associated with increased long-term mortality when compared with moderate or no PPM. Evidence suggests that PPM is associated with increased incidence of postoperative PH. Patient–prosthesis mismatch, Mitral valve replacement, Long-term mortality, Outcomes INTRODUCTION A best evidence topic was constructed according to a structured protocol. This is fully described in the ICVTS [1]. THREE-PART QUESTION In [patients undergoing mitral valve replacement] does [patient–prosthesis mismatch] have a negative impact in terms of [postoperative mortality, incidence of postoperative pulmonary hypertension and transmitral gradients]? CLINICAL SCENARIO Mitral valve replacement (MVR) in a 65-year-old female patient with severe mitral stenosis was performed. Having analysed the postoperative echocardiography, the patient was diagnosed with a patient–prosthesis mismatch (PPM). A recent paper published that in patients undergoing aortic valve replacement, a moderate or severe PPM is known to worsen postoperative results, specifically the early and mid-term survival rates [2]. Therefore, you wonder whether PPM following MVR might have a negative impact on the patient’s clinical outcomes and you resolve to search the literature yourself. SEARCH STRATEGY The literature was reviewed by searching Medline from 1950 to July 2017 using PubMed interface: [(Mitral valve) AND (Replacement) AND (Mismatch)]. In addition, similar searches were performed in OVID, EMBASE and Cochrane Central Registry of Controlled Trials. SEARCH OUTCOME A total of 103 papers were found using the reported search. Of these, 18 papers were identified to provide the best available evidence to answer the clinical question. These are presented in Table 1. Table 1: Best evidence papers Author, date, journal and country Study type (level of evidence) Patient group Outcomes Key results Comments Ammannaya et al. (2017), Eur J Cardiothorac Surg, India [3] Retrospective cohort study (level 2b) n = 500 patients PPM: 37.2% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 PH defined as SPAP >40 mmHg Follow-up: 8.15 ± 3.2-years Mortality at 10 years No PPM vs PPM: 18.6% vs 29.2% (P < 0.001) Lower regression of PH was seen in patients with PPM The difference in mortality and freedom from cardiac death remains with propensity matching of the groups EOA measured through CE Mortality at 20 years No PPM vs PPM: 29.9% vs 45.2% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 87.6% vs 76.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 81.2% vs 60.9% (P < 0.001) Incidence of preoperative PH No PPM vs PPM: 81.8% vs 83.3% (P = 0.67) Incidence of postoperative PH No PPM vs PPM: 19.4% vs 66.1% (P < 0.001) Peak PTG No PPM vs PPM: 7.5 ± 3.5 mmHg vs 12.3 ± 4.3 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3.2 ± 1.2 mmHg vs 5.5 ± 1.5 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 30.49 ± 8.2 mmHg vs 42.35 ± 8.4 mmHg (P < 0.001) Hwang et al. (2016), Ann Thorac Surg, Korea [4] Retrospective cohort study (level 2b) n = 760 patients PPM: 19.3% Valve Bioprosthetic: 15.8% Mechanical: 84.2% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 127 months Mortality at 10 years No PPM vs PPM: 14.4% vs 25.1% (P < 0.001) EOA obtained from the literature Propensity score limited due to the small number of patients (n = 60) Mortality at 20 years No PPM vs PPM: 26.6% vs 38.6% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 92.2% vs 80.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 84.7% vs 57.5% (P < 0.001) Borracci et al. (2016), Cardiol J, Argentina [5] Retrospective cohort study (level 2b) n = 136 patients Moderate PPM: 44.1% Severe PPM: 26.4% Valve Bioprosthetic: 43% Mechanical: 57% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Severe PH defined as SPAP >55 mmHg Follow-up: 60 months Mortality at 5 years No PPM vs moderate PPM vs severe PPM: 10.5% vs 6.3% vs 44.1% (P = 0.043) EOA obtained from the literature Mortality at 5 years in patients with severe PH No PPM or moderate PPM vs severe PPM or moderate PPM: 4.9% vs 25.1% (P = 0.016) Aziz et al. (2010), Ann Thorac Surg, USA [6] Retrospective cohort study (level 2b) n = 765 patients Moderate PPM: 37.3% Severe PPM: 13.9% Valve Bioprosthetic: 42% Mechanical: 58% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 58 ± 51 months Mortality at 10 years EOA obtained from the literature No PPM 44% ± 5% Moderate PPM 48% ± 6% Severe PPM 59% ± 9% (P = 0.02) Magne et al. (2007), Circulation, Canada [7] Retrospective cohort study (level 2b) n = 929 patients Moderate PPM: 69.3% Severe PPM: 8.7% Valve Bioprosthetic: 15.1% Mechanical: 84.9% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.3 ± 4.5 years Mortality at 6 years No PPM vs moderate PPM: 10% ± 2% vs 16% ± 1% (P = 0.029) EOA was either measured through CE or obtained from the literature No PPM vs severe PPM: 10% ± 2% vs 26% ± 5% (P = 0.002) Mortality at 12 years No PPM vs moderate PPM: 18% ± 4% vs 24% ± 2% (P = 0.029) No PPM vs severe PPM: 18% ± 4% vs 37% ± 7% (P = 0.002) Peak PTG No PPM 8 ± 2.4 mmHg Moderate PPM 9.8 ± 3.3 mmHg Severe PPM 13.4 ± 4.6 mmHg (P < 0.001) Mean PTG No PPM 2.6 ± 1.0 mmHg Moderate PPM 3.9 ± 1.3 mmHg Severe PPM 6.0 ± .6 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs moderate PPM vs severe PPM: 38 ± 9 mmHg vs 41 ± 8 mmHg vs 49 ± 12 mmHg (P < 0.001) Sato et al. (2014), Circ J, Japan [8] Retrospective cohort study (level 2b) n = 142 patients PPM: 42.3% Valve Bioprosthetic: 22.5% Mechanical: 77.5% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 7.0 ± 3.5 years Mortality PPM was associated with increased long-term mortality (P < 0.05) EOA obtained from the literature Mean PTG No PPM vs PPM: 3.7 ± 1.2 mmHg vs 4.8 ± 1.5 mmHg (P < 0.001) Bouchard et al. (2010), Can J Cardiol, Canada [9] Retrospective cohort study (level 2b) n = 714 patients PPM: 10.3% Valve Mechanical: 100% PPM defined as iEOA <1.3 cm2/m2 Follow-up: 1871 ± 1178 days Mortality at 5 years No PPM vs PPM: 16.4% ± 1.7% vs 24.8% ± 6.2% (P = 0.007) EOA obtained from the literature Mortality at 10 years No PPM vs PPM: 32.6% ± 4.2% vs 46.1% ± 16.3% (P = 0.007) Lam et al. (2007), J Thorac Cardiovasc Surg, Canada [10] Retrospective cohort study (level 2b) n = 884 patients PPM: 31.6% Valve Bioprosthetic: 25.7% Mechanical: 74.3% PPM defined as iEOA ≤1.25 cm2/m2 Follow-up: 5.1 ± 4.1 years Mortality at 5 years No PPM vs PPM: 14% vs 22% (P = 0.05) EOA obtained from the literature or by the manufacturer Mortality at 10 years No PPM vs PPM: 25% vs 35% (P = 0.05) Jamieson et al. (2009), Ann Thorac Surg, Canada [11] Retrospective cohort study (level 2b) n = 2440 patients Moderate PPM: 69.5% Severe PPM: 16.3% Valve Bioprosthetic: 55.6% Mechanical: 44.4% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.1 ± 4.6 years Early mortality No PPM vs moderate PPM vs severe PPM: 5.5% vs 6.3% vs 8.5% (P = 0.182) EOA obtained from the literature or by echocardiography Late mortality No PPM vs moderate PPM vs severe PPM: 36.8% vs 32.8% vs 22.6% (P = NS) Incidence of preoperative PH No PPM vs moderate PPM vs severe PPM: 34.5% vs 37.4% vs 56.9% (P < 0.0001) Angeloni et al. (2013), Int J Cardiol, Italy [12] Retrospective cohort study (level 2b) n = 210 patients PPM: 42% Valve Bioprosthetic: 35.8% Mechanical: 64.2% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Follow-up: 27 months Mortality at follow-up No PPM vs PPM: 12.3% vs 12.5% (P = 0.83) EOA measured through CE Incidence of preoperative PH No PPM vs PPM: 70% vs 72% (P = 0.47) Incidence of PH at follow-up No PPM vs PPM: 24% vs 61% (P < 0.0001) Mean PTG No PPM vs PPM: 3.2 ± 2.5 mmHg vs 4.7 ± 1.1 mmHg (P < 0.0001) Mean postoperative SPAP No PPM vs PPM: 31 ± 6 mmHg vs 41 ± 9 mmHg (P < 0.0001) Pisano et al. (2016), J Heart Valve Dis, Italy [13] Retrospective cohort study (level 2b) n = 46 patients PPM: 25% Valve Bioprosthesis: 19.57% Mechanical: 80.43% PPM defined as iEOA <1.2 cm2/m2 Mean follow-up: 6.9 ± 1.8 years Mortality at follow-up No PPM vs PPM: 0% vs 0% EOA measured through CE Shi et al. (2011), Heart, Australia [14] Retrospective cohort study (level 2b) n = 1006 patients Moderate PPM: 52.8% Severe PPM: 13.2% Valve Bioprosthetic: 38% Mechanical: 62% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 7 years Mortality at 7 years No PPM vs moderate PPM vs severe PPM: 28% ± 4% vs 24% ± 2% vs 31% ± 10.3% (P = 0.76) EOA obtained from the literature Matsuura et al. (2011), Ann Thorac Cardiovasc Surg, Japan [15] Retrospective cohort study (level 2b) n = 212 patients PPM: 59% Valve Bioprosthetic: 34.9% Mechanical: 65.1% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 4.5 ± 8.4 years Late mortality No PPM vs PPM: 7% vs 9.6% (P = 0.1) EOA obtained from the literature or by echocardiography Peak PTG No PPM vs PPM: 9.8 ± 4.5 mmHg vs 11.9 ± 6.2 mmHg (P = 0.042) Mean PTG No PPM vs PPM: 3.6 ± 2.1 mmHg vs 4.0 ± 1.9 mmHg (P = 0.21) Sakamoto et al. (2010), Ann Thorac Cardiovasc Surg, Japan [16] Retrospective cohort study (level 2b) n = 84 patients PPM: 29.7% Valve Bioprosthetic: 10.7% Mechanical: 89.3% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 8.5 ± 3.9 years Freedom of cardiac death at: No PPM vs PPM: EOA measured through echocardiography 5 years 96% vs 100% 10 years 93% vs 95% 14 years 82% vs 95% (P > 0.05) Cho et al. (2016), Yonsei Med J, Korea [17] Retrospective cohort study (level 2b) n = 166 patients Moderate PPM: 48% Severe PPM: 14% Valve Bioprosthetic: 22% Mechanical: 78% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 16 months Mean PTG No PPM vs PPM: 3.2 ± 1.1 mmHg vs 3.7 ± 1.2 mmHg (P < 0.021) In both groups, transmitral gradients remained below mild in terms of stenosis Mean postoperative SPAP No PPM vs moderate PPM: 25 ± 6 mmHg vs 28 ± 6 mmHg (P < 0.007) EOA obtained from the literature, manufacturer or by echocardiography Moderate PPM vs severe PPM: 28 ± 6 mmHg vs 33 ± 11 mmHg (P < 0.037) Cao et al. (2015), Med Sci Monit, China [18] Retrospective cohort study (level 2b) n = 493 patients PPM: 31.8% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 3 years Mean PTG No PPM vs PPM: 14.89 ± 5.77 vs 25.34 ± 6.35 (P < 0.01) Severe postoperative mitral stenosis at follow-up even in those patients with no PPM EOA measured through CE Mean postoperative SPAP No PPM vs PPM: 43.17 ± 12.17 mmHg vs 53.29 ± 10.63 mmHg (P < 0.01) Li et al. (2005), J Am Coll Cardiol, Canada [19] Retrospective cohort study (level 2b) n = 56 patients PPM: 71.4% Valve Bioprosthetic: 16% Mechanical: 84% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Incidence of preoperative PH No PPM vs PPM: 69% vs 66% (P > 0.05) Lower regression of PH was observed in patients with PPM EOA measured through CE Incidence of postoperative PH No PPM vs PPM: 19% vs 68% (P = 0.001) Peak PTG No PPM vs PPM: 8 ± 2 mmHg vs 12 ± 4 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3 ± 1 mmHg vs 4 ± 2 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 46 ± 8 mmHg (P < 0.001) Ozyalcin et al. (2016), J Heart Valve Dis, Turkey [20] Retrospective cohort study (level 2b) n = 128 patients PPM: 35% Valve Mechanical: 100% PPM defined as iEOA <1.19 cm2/m2 Follow-up: 46 ± 9 months Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 45 ± 7 mmHg (P < 0.0001) EOA measured through CE Author, date, journal and country Study type (level of evidence) Patient group Outcomes Key results Comments Ammannaya et al. (2017), Eur J Cardiothorac Surg, India [3] Retrospective cohort study (level 2b) n = 500 patients PPM: 37.2% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 PH defined as SPAP >40 mmHg Follow-up: 8.15 ± 3.2-years Mortality at 10 years No PPM vs PPM: 18.6% vs 29.2% (P < 0.001) Lower regression of PH was seen in patients with PPM The difference in mortality and freedom from cardiac death remains with propensity matching of the groups EOA measured through CE Mortality at 20 years No PPM vs PPM: 29.9% vs 45.2% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 87.6% vs 76.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 81.2% vs 60.9% (P < 0.001) Incidence of preoperative PH No PPM vs PPM: 81.8% vs 83.3% (P = 0.67) Incidence of postoperative PH No PPM vs PPM: 19.4% vs 66.1% (P < 0.001) Peak PTG No PPM vs PPM: 7.5 ± 3.5 mmHg vs 12.3 ± 4.3 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3.2 ± 1.2 mmHg vs 5.5 ± 1.5 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 30.49 ± 8.2 mmHg vs 42.35 ± 8.4 mmHg (P < 0.001) Hwang et al. (2016), Ann Thorac Surg, Korea [4] Retrospective cohort study (level 2b) n = 760 patients PPM: 19.3% Valve Bioprosthetic: 15.8% Mechanical: 84.2% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 127 months Mortality at 10 years No PPM vs PPM: 14.4% vs 25.1% (P < 0.001) EOA obtained from the literature Propensity score limited due to the small number of patients (n = 60) Mortality at 20 years No PPM vs PPM: 26.6% vs 38.6% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 92.2% vs 80.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 84.7% vs 57.5% (P < 0.001) Borracci et al. (2016), Cardiol J, Argentina [5] Retrospective cohort study (level 2b) n = 136 patients Moderate PPM: 44.1% Severe PPM: 26.4% Valve Bioprosthetic: 43% Mechanical: 57% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Severe PH defined as SPAP >55 mmHg Follow-up: 60 months Mortality at 5 years No PPM vs moderate PPM vs severe PPM: 10.5% vs 6.3% vs 44.1% (P = 0.043) EOA obtained from the literature Mortality at 5 years in patients with severe PH No PPM or moderate PPM vs severe PPM or moderate PPM: 4.9% vs 25.1% (P = 0.016) Aziz et al. (2010), Ann Thorac Surg, USA [6] Retrospective cohort study (level 2b) n = 765 patients Moderate PPM: 37.3% Severe PPM: 13.9% Valve Bioprosthetic: 42% Mechanical: 58% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 58 ± 51 months Mortality at 10 years EOA obtained from the literature No PPM 44% ± 5% Moderate PPM 48% ± 6% Severe PPM 59% ± 9% (P = 0.02) Magne et al. (2007), Circulation, Canada [7] Retrospective cohort study (level 2b) n = 929 patients Moderate PPM: 69.3% Severe PPM: 8.7% Valve Bioprosthetic: 15.1% Mechanical: 84.9% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.3 ± 4.5 years Mortality at 6 years No PPM vs moderate PPM: 10% ± 2% vs 16% ± 1% (P = 0.029) EOA was either measured through CE or obtained from the literature No PPM vs severe PPM: 10% ± 2% vs 26% ± 5% (P = 0.002) Mortality at 12 years No PPM vs moderate PPM: 18% ± 4% vs 24% ± 2% (P = 0.029) No PPM vs severe PPM: 18% ± 4% vs 37% ± 7% (P = 0.002) Peak PTG No PPM 8 ± 2.4 mmHg Moderate PPM 9.8 ± 3.3 mmHg Severe PPM 13.4 ± 4.6 mmHg (P < 0.001) Mean PTG No PPM 2.6 ± 1.0 mmHg Moderate PPM 3.9 ± 1.3 mmHg Severe PPM 6.0 ± .6 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs moderate PPM vs severe PPM: 38 ± 9 mmHg vs 41 ± 8 mmHg vs 49 ± 12 mmHg (P < 0.001) Sato et al. (2014), Circ J, Japan [8] Retrospective cohort study (level 2b) n = 142 patients PPM: 42.3% Valve Bioprosthetic: 22.5% Mechanical: 77.5% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 7.0 ± 3.5 years Mortality PPM was associated with increased long-term mortality (P < 0.05) EOA obtained from the literature Mean PTG No PPM vs PPM: 3.7 ± 1.2 mmHg vs 4.8 ± 1.5 mmHg (P < 0.001) Bouchard et al. (2010), Can J Cardiol, Canada [9] Retrospective cohort study (level 2b) n = 714 patients PPM: 10.3% Valve Mechanical: 100% PPM defined as iEOA <1.3 cm2/m2 Follow-up: 1871 ± 1178 days Mortality at 5 years No PPM vs PPM: 16.4% ± 1.7% vs 24.8% ± 6.2% (P = 0.007) EOA obtained from the literature Mortality at 10 years No PPM vs PPM: 32.6% ± 4.2% vs 46.1% ± 16.3% (P = 0.007) Lam et al. (2007), J Thorac Cardiovasc Surg, Canada [10] Retrospective cohort study (level 2b) n = 884 patients PPM: 31.6% Valve Bioprosthetic: 25.7% Mechanical: 74.3% PPM defined as iEOA ≤1.25 cm2/m2 Follow-up: 5.1 ± 4.1 years Mortality at 5 years No PPM vs PPM: 14% vs 22% (P = 0.05) EOA obtained from the literature or by the manufacturer Mortality at 10 years No PPM vs PPM: 25% vs 35% (P = 0.05) Jamieson et al. (2009), Ann Thorac Surg, Canada [11] Retrospective cohort study (level 2b) n = 2440 patients Moderate PPM: 69.5% Severe PPM: 16.3% Valve Bioprosthetic: 55.6% Mechanical: 44.4% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.1 ± 4.6 years Early mortality No PPM vs moderate PPM vs severe PPM: 5.5% vs 6.3% vs 8.5% (P = 0.182) EOA obtained from the literature or by echocardiography Late mortality No PPM vs moderate PPM vs severe PPM: 36.8% vs 32.8% vs 22.6% (P = NS) Incidence of preoperative PH No PPM vs moderate PPM vs severe PPM: 34.5% vs 37.4% vs 56.9% (P < 0.0001) Angeloni et al. (2013), Int J Cardiol, Italy [12] Retrospective cohort study (level 2b) n = 210 patients PPM: 42% Valve Bioprosthetic: 35.8% Mechanical: 64.2% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Follow-up: 27 months Mortality at follow-up No PPM vs PPM: 12.3% vs 12.5% (P = 0.83) EOA measured through CE Incidence of preoperative PH No PPM vs PPM: 70% vs 72% (P = 0.47) Incidence of PH at follow-up No PPM vs PPM: 24% vs 61% (P < 0.0001) Mean PTG No PPM vs PPM: 3.2 ± 2.5 mmHg vs 4.7 ± 1.1 mmHg (P < 0.0001) Mean postoperative SPAP No PPM vs PPM: 31 ± 6 mmHg vs 41 ± 9 mmHg (P < 0.0001) Pisano et al. (2016), J Heart Valve Dis, Italy [13] Retrospective cohort study (level 2b) n = 46 patients PPM: 25% Valve Bioprosthesis: 19.57% Mechanical: 80.43% PPM defined as iEOA <1.2 cm2/m2 Mean follow-up: 6.9 ± 1.8 years Mortality at follow-up No PPM vs PPM: 0% vs 0% EOA measured through CE Shi et al. (2011), Heart, Australia [14] Retrospective cohort study (level 2b) n = 1006 patients Moderate PPM: 52.8% Severe PPM: 13.2% Valve Bioprosthetic: 38% Mechanical: 62% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 7 years Mortality at 7 years No PPM vs moderate PPM vs severe PPM: 28% ± 4% vs 24% ± 2% vs 31% ± 10.3% (P = 0.76) EOA obtained from the literature Matsuura et al. (2011), Ann Thorac Cardiovasc Surg, Japan [15] Retrospective cohort study (level 2b) n = 212 patients PPM: 59% Valve Bioprosthetic: 34.9% Mechanical: 65.1% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 4.5 ± 8.4 years Late mortality No PPM vs PPM: 7% vs 9.6% (P = 0.1) EOA obtained from the literature or by echocardiography Peak PTG No PPM vs PPM: 9.8 ± 4.5 mmHg vs 11.9 ± 6.2 mmHg (P = 0.042) Mean PTG No PPM vs PPM: 3.6 ± 2.1 mmHg vs 4.0 ± 1.9 mmHg (P = 0.21) Sakamoto et al. (2010), Ann Thorac Cardiovasc Surg, Japan [16] Retrospective cohort study (level 2b) n = 84 patients PPM: 29.7% Valve Bioprosthetic: 10.7% Mechanical: 89.3% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 8.5 ± 3.9 years Freedom of cardiac death at: No PPM vs PPM: EOA measured through echocardiography 5 years 96% vs 100% 10 years 93% vs 95% 14 years 82% vs 95% (P > 0.05) Cho et al. (2016), Yonsei Med J, Korea [17] Retrospective cohort study (level 2b) n = 166 patients Moderate PPM: 48% Severe PPM: 14% Valve Bioprosthetic: 22% Mechanical: 78% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 16 months Mean PTG No PPM vs PPM: 3.2 ± 1.1 mmHg vs 3.7 ± 1.2 mmHg (P < 0.021) In both groups, transmitral gradients remained below mild in terms of stenosis Mean postoperative SPAP No PPM vs moderate PPM: 25 ± 6 mmHg vs 28 ± 6 mmHg (P < 0.007) EOA obtained from the literature, manufacturer or by echocardiography Moderate PPM vs severe PPM: 28 ± 6 mmHg vs 33 ± 11 mmHg (P < 0.037) Cao et al. (2015), Med Sci Monit, China [18] Retrospective cohort study (level 2b) n = 493 patients PPM: 31.8% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 3 years Mean PTG No PPM vs PPM: 14.89 ± 5.77 vs 25.34 ± 6.35 (P < 0.01) Severe postoperative mitral stenosis at follow-up even in those patients with no PPM EOA measured through CE Mean postoperative SPAP No PPM vs PPM: 43.17 ± 12.17 mmHg vs 53.29 ± 10.63 mmHg (P < 0.01) Li et al. (2005), J Am Coll Cardiol, Canada [19] Retrospective cohort study (level 2b) n = 56 patients PPM: 71.4% Valve Bioprosthetic: 16% Mechanical: 84% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Incidence of preoperative PH No PPM vs PPM: 69% vs 66% (P > 0.05) Lower regression of PH was observed in patients with PPM EOA measured through CE Incidence of postoperative PH No PPM vs PPM: 19% vs 68% (P = 0.001) Peak PTG No PPM vs PPM: 8 ± 2 mmHg vs 12 ± 4 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3 ± 1 mmHg vs 4 ± 2 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 46 ± 8 mmHg (P < 0.001) Ozyalcin et al. (2016), J Heart Valve Dis, Turkey [20] Retrospective cohort study (level 2b) n = 128 patients PPM: 35% Valve Mechanical: 100% PPM defined as iEOA <1.19 cm2/m2 Follow-up: 46 ± 9 months Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 45 ± 7 mmHg (P < 0.0001) EOA measured through CE CE: continuity equation; iEOA: indexed effective orifice area; PH: pulmonary hypertension; PPM: patient–prosthesis mismatch; PTG: postoperative transmitral gradient; SPAP: systolic pulmonary artery pressure. Table 1: Best evidence papers Author, date, journal and country Study type (level of evidence) Patient group Outcomes Key results Comments Ammannaya et al. (2017), Eur J Cardiothorac Surg, India [3] Retrospective cohort study (level 2b) n = 500 patients PPM: 37.2% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 PH defined as SPAP >40 mmHg Follow-up: 8.15 ± 3.2-years Mortality at 10 years No PPM vs PPM: 18.6% vs 29.2% (P < 0.001) Lower regression of PH was seen in patients with PPM The difference in mortality and freedom from cardiac death remains with propensity matching of the groups EOA measured through CE Mortality at 20 years No PPM vs PPM: 29.9% vs 45.2% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 87.6% vs 76.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 81.2% vs 60.9% (P < 0.001) Incidence of preoperative PH No PPM vs PPM: 81.8% vs 83.3% (P = 0.67) Incidence of postoperative PH No PPM vs PPM: 19.4% vs 66.1% (P < 0.001) Peak PTG No PPM vs PPM: 7.5 ± 3.5 mmHg vs 12.3 ± 4.3 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3.2 ± 1.2 mmHg vs 5.5 ± 1.5 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 30.49 ± 8.2 mmHg vs 42.35 ± 8.4 mmHg (P < 0.001) Hwang et al. (2016), Ann Thorac Surg, Korea [4] Retrospective cohort study (level 2b) n = 760 patients PPM: 19.3% Valve Bioprosthetic: 15.8% Mechanical: 84.2% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 127 months Mortality at 10 years No PPM vs PPM: 14.4% vs 25.1% (P < 0.001) EOA obtained from the literature Propensity score limited due to the small number of patients (n = 60) Mortality at 20 years No PPM vs PPM: 26.6% vs 38.6% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 92.2% vs 80.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 84.7% vs 57.5% (P < 0.001) Borracci et al. (2016), Cardiol J, Argentina [5] Retrospective cohort study (level 2b) n = 136 patients Moderate PPM: 44.1% Severe PPM: 26.4% Valve Bioprosthetic: 43% Mechanical: 57% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Severe PH defined as SPAP >55 mmHg Follow-up: 60 months Mortality at 5 years No PPM vs moderate PPM vs severe PPM: 10.5% vs 6.3% vs 44.1% (P = 0.043) EOA obtained from the literature Mortality at 5 years in patients with severe PH No PPM or moderate PPM vs severe PPM or moderate PPM: 4.9% vs 25.1% (P = 0.016) Aziz et al. (2010), Ann Thorac Surg, USA [6] Retrospective cohort study (level 2b) n = 765 patients Moderate PPM: 37.3% Severe PPM: 13.9% Valve Bioprosthetic: 42% Mechanical: 58% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 58 ± 51 months Mortality at 10 years EOA obtained from the literature No PPM 44% ± 5% Moderate PPM 48% ± 6% Severe PPM 59% ± 9% (P = 0.02) Magne et al. (2007), Circulation, Canada [7] Retrospective cohort study (level 2b) n = 929 patients Moderate PPM: 69.3% Severe PPM: 8.7% Valve Bioprosthetic: 15.1% Mechanical: 84.9% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.3 ± 4.5 years Mortality at 6 years No PPM vs moderate PPM: 10% ± 2% vs 16% ± 1% (P = 0.029) EOA was either measured through CE or obtained from the literature No PPM vs severe PPM: 10% ± 2% vs 26% ± 5% (P = 0.002) Mortality at 12 years No PPM vs moderate PPM: 18% ± 4% vs 24% ± 2% (P = 0.029) No PPM vs severe PPM: 18% ± 4% vs 37% ± 7% (P = 0.002) Peak PTG No PPM 8 ± 2.4 mmHg Moderate PPM 9.8 ± 3.3 mmHg Severe PPM 13.4 ± 4.6 mmHg (P < 0.001) Mean PTG No PPM 2.6 ± 1.0 mmHg Moderate PPM 3.9 ± 1.3 mmHg Severe PPM 6.0 ± .6 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs moderate PPM vs severe PPM: 38 ± 9 mmHg vs 41 ± 8 mmHg vs 49 ± 12 mmHg (P < 0.001) Sato et al. (2014), Circ J, Japan [8] Retrospective cohort study (level 2b) n = 142 patients PPM: 42.3% Valve Bioprosthetic: 22.5% Mechanical: 77.5% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 7.0 ± 3.5 years Mortality PPM was associated with increased long-term mortality (P < 0.05) EOA obtained from the literature Mean PTG No PPM vs PPM: 3.7 ± 1.2 mmHg vs 4.8 ± 1.5 mmHg (P < 0.001) Bouchard et al. (2010), Can J Cardiol, Canada [9] Retrospective cohort study (level 2b) n = 714 patients PPM: 10.3% Valve Mechanical: 100% PPM defined as iEOA <1.3 cm2/m2 Follow-up: 1871 ± 1178 days Mortality at 5 years No PPM vs PPM: 16.4% ± 1.7% vs 24.8% ± 6.2% (P = 0.007) EOA obtained from the literature Mortality at 10 years No PPM vs PPM: 32.6% ± 4.2% vs 46.1% ± 16.3% (P = 0.007) Lam et al. (2007), J Thorac Cardiovasc Surg, Canada [10] Retrospective cohort study (level 2b) n = 884 patients PPM: 31.6% Valve Bioprosthetic: 25.7% Mechanical: 74.3% PPM defined as iEOA ≤1.25 cm2/m2 Follow-up: 5.1 ± 4.1 years Mortality at 5 years No PPM vs PPM: 14% vs 22% (P = 0.05) EOA obtained from the literature or by the manufacturer Mortality at 10 years No PPM vs PPM: 25% vs 35% (P = 0.05) Jamieson et al. (2009), Ann Thorac Surg, Canada [11] Retrospective cohort study (level 2b) n = 2440 patients Moderate PPM: 69.5% Severe PPM: 16.3% Valve Bioprosthetic: 55.6% Mechanical: 44.4% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.1 ± 4.6 years Early mortality No PPM vs moderate PPM vs severe PPM: 5.5% vs 6.3% vs 8.5% (P = 0.182) EOA obtained from the literature or by echocardiography Late mortality No PPM vs moderate PPM vs severe PPM: 36.8% vs 32.8% vs 22.6% (P = NS) Incidence of preoperative PH No PPM vs moderate PPM vs severe PPM: 34.5% vs 37.4% vs 56.9% (P < 0.0001) Angeloni et al. (2013), Int J Cardiol, Italy [12] Retrospective cohort study (level 2b) n = 210 patients PPM: 42% Valve Bioprosthetic: 35.8% Mechanical: 64.2% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Follow-up: 27 months Mortality at follow-up No PPM vs PPM: 12.3% vs 12.5% (P = 0.83) EOA measured through CE Incidence of preoperative PH No PPM vs PPM: 70% vs 72% (P = 0.47) Incidence of PH at follow-up No PPM vs PPM: 24% vs 61% (P < 0.0001) Mean PTG No PPM vs PPM: 3.2 ± 2.5 mmHg vs 4.7 ± 1.1 mmHg (P < 0.0001) Mean postoperative SPAP No PPM vs PPM: 31 ± 6 mmHg vs 41 ± 9 mmHg (P < 0.0001) Pisano et al. (2016), J Heart Valve Dis, Italy [13] Retrospective cohort study (level 2b) n = 46 patients PPM: 25% Valve Bioprosthesis: 19.57% Mechanical: 80.43% PPM defined as iEOA <1.2 cm2/m2 Mean follow-up: 6.9 ± 1.8 years Mortality at follow-up No PPM vs PPM: 0% vs 0% EOA measured through CE Shi et al. (2011), Heart, Australia [14] Retrospective cohort study (level 2b) n = 1006 patients Moderate PPM: 52.8% Severe PPM: 13.2% Valve Bioprosthetic: 38% Mechanical: 62% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 7 years Mortality at 7 years No PPM vs moderate PPM vs severe PPM: 28% ± 4% vs 24% ± 2% vs 31% ± 10.3% (P = 0.76) EOA obtained from the literature Matsuura et al. (2011), Ann Thorac Cardiovasc Surg, Japan [15] Retrospective cohort study (level 2b) n = 212 patients PPM: 59% Valve Bioprosthetic: 34.9% Mechanical: 65.1% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 4.5 ± 8.4 years Late mortality No PPM vs PPM: 7% vs 9.6% (P = 0.1) EOA obtained from the literature or by echocardiography Peak PTG No PPM vs PPM: 9.8 ± 4.5 mmHg vs 11.9 ± 6.2 mmHg (P = 0.042) Mean PTG No PPM vs PPM: 3.6 ± 2.1 mmHg vs 4.0 ± 1.9 mmHg (P = 0.21) Sakamoto et al. (2010), Ann Thorac Cardiovasc Surg, Japan [16] Retrospective cohort study (level 2b) n = 84 patients PPM: 29.7% Valve Bioprosthetic: 10.7% Mechanical: 89.3% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 8.5 ± 3.9 years Freedom of cardiac death at: No PPM vs PPM: EOA measured through echocardiography 5 years 96% vs 100% 10 years 93% vs 95% 14 years 82% vs 95% (P > 0.05) Cho et al. (2016), Yonsei Med J, Korea [17] Retrospective cohort study (level 2b) n = 166 patients Moderate PPM: 48% Severe PPM: 14% Valve Bioprosthetic: 22% Mechanical: 78% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 16 months Mean PTG No PPM vs PPM: 3.2 ± 1.1 mmHg vs 3.7 ± 1.2 mmHg (P < 0.021) In both groups, transmitral gradients remained below mild in terms of stenosis Mean postoperative SPAP No PPM vs moderate PPM: 25 ± 6 mmHg vs 28 ± 6 mmHg (P < 0.007) EOA obtained from the literature, manufacturer or by echocardiography Moderate PPM vs severe PPM: 28 ± 6 mmHg vs 33 ± 11 mmHg (P < 0.037) Cao et al. (2015), Med Sci Monit, China [18] Retrospective cohort study (level 2b) n = 493 patients PPM: 31.8% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 3 years Mean PTG No PPM vs PPM: 14.89 ± 5.77 vs 25.34 ± 6.35 (P < 0.01) Severe postoperative mitral stenosis at follow-up even in those patients with no PPM EOA measured through CE Mean postoperative SPAP No PPM vs PPM: 43.17 ± 12.17 mmHg vs 53.29 ± 10.63 mmHg (P < 0.01) Li et al. (2005), J Am Coll Cardiol, Canada [19] Retrospective cohort study (level 2b) n = 56 patients PPM: 71.4% Valve Bioprosthetic: 16% Mechanical: 84% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Incidence of preoperative PH No PPM vs PPM: 69% vs 66% (P > 0.05) Lower regression of PH was observed in patients with PPM EOA measured through CE Incidence of postoperative PH No PPM vs PPM: 19% vs 68% (P = 0.001) Peak PTG No PPM vs PPM: 8 ± 2 mmHg vs 12 ± 4 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3 ± 1 mmHg vs 4 ± 2 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 46 ± 8 mmHg (P < 0.001) Ozyalcin et al. (2016), J Heart Valve Dis, Turkey [20] Retrospective cohort study (level 2b) n = 128 patients PPM: 35% Valve Mechanical: 100% PPM defined as iEOA <1.19 cm2/m2 Follow-up: 46 ± 9 months Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 45 ± 7 mmHg (P < 0.0001) EOA measured through CE Author, date, journal and country Study type (level of evidence) Patient group Outcomes Key results Comments Ammannaya et al. (2017), Eur J Cardiothorac Surg, India [3] Retrospective cohort study (level 2b) n = 500 patients PPM: 37.2% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 PH defined as SPAP >40 mmHg Follow-up: 8.15 ± 3.2-years Mortality at 10 years No PPM vs PPM: 18.6% vs 29.2% (P < 0.001) Lower regression of PH was seen in patients with PPM The difference in mortality and freedom from cardiac death remains with propensity matching of the groups EOA measured through CE Mortality at 20 years No PPM vs PPM: 29.9% vs 45.2% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 87.6% vs 76.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 81.2% vs 60.9% (P < 0.001) Incidence of preoperative PH No PPM vs PPM: 81.8% vs 83.3% (P = 0.67) Incidence of postoperative PH No PPM vs PPM: 19.4% vs 66.1% (P < 0.001) Peak PTG No PPM vs PPM: 7.5 ± 3.5 mmHg vs 12.3 ± 4.3 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3.2 ± 1.2 mmHg vs 5.5 ± 1.5 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 30.49 ± 8.2 mmHg vs 42.35 ± 8.4 mmHg (P < 0.001) Hwang et al. (2016), Ann Thorac Surg, Korea [4] Retrospective cohort study (level 2b) n = 760 patients PPM: 19.3% Valve Bioprosthetic: 15.8% Mechanical: 84.2% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 127 months Mortality at 10 years No PPM vs PPM: 14.4% vs 25.1% (P < 0.001) EOA obtained from the literature Propensity score limited due to the small number of patients (n = 60) Mortality at 20 years No PPM vs PPM: 26.6% vs 38.6% (P < 0.001) Freedom from cardiac death at 10 years No PPM vs PPM: 92.2% vs 80.8% (P < 0.001) Freedom from cardiac death at 20 years No PPM vs PPM: 84.7% vs 57.5% (P < 0.001) Borracci et al. (2016), Cardiol J, Argentina [5] Retrospective cohort study (level 2b) n = 136 patients Moderate PPM: 44.1% Severe PPM: 26.4% Valve Bioprosthetic: 43% Mechanical: 57% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Severe PH defined as SPAP >55 mmHg Follow-up: 60 months Mortality at 5 years No PPM vs moderate PPM vs severe PPM: 10.5% vs 6.3% vs 44.1% (P = 0.043) EOA obtained from the literature Mortality at 5 years in patients with severe PH No PPM or moderate PPM vs severe PPM or moderate PPM: 4.9% vs 25.1% (P = 0.016) Aziz et al. (2010), Ann Thorac Surg, USA [6] Retrospective cohort study (level 2b) n = 765 patients Moderate PPM: 37.3% Severe PPM: 13.9% Valve Bioprosthetic: 42% Mechanical: 58% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 58 ± 51 months Mortality at 10 years EOA obtained from the literature No PPM 44% ± 5% Moderate PPM 48% ± 6% Severe PPM 59% ± 9% (P = 0.02) Magne et al. (2007), Circulation, Canada [7] Retrospective cohort study (level 2b) n = 929 patients Moderate PPM: 69.3% Severe PPM: 8.7% Valve Bioprosthetic: 15.1% Mechanical: 84.9% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.3 ± 4.5 years Mortality at 6 years No PPM vs moderate PPM: 10% ± 2% vs 16% ± 1% (P = 0.029) EOA was either measured through CE or obtained from the literature No PPM vs severe PPM: 10% ± 2% vs 26% ± 5% (P = 0.002) Mortality at 12 years No PPM vs moderate PPM: 18% ± 4% vs 24% ± 2% (P = 0.029) No PPM vs severe PPM: 18% ± 4% vs 37% ± 7% (P = 0.002) Peak PTG No PPM 8 ± 2.4 mmHg Moderate PPM 9.8 ± 3.3 mmHg Severe PPM 13.4 ± 4.6 mmHg (P < 0.001) Mean PTG No PPM 2.6 ± 1.0 mmHg Moderate PPM 3.9 ± 1.3 mmHg Severe PPM 6.0 ± .6 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs moderate PPM vs severe PPM: 38 ± 9 mmHg vs 41 ± 8 mmHg vs 49 ± 12 mmHg (P < 0.001) Sato et al. (2014), Circ J, Japan [8] Retrospective cohort study (level 2b) n = 142 patients PPM: 42.3% Valve Bioprosthetic: 22.5% Mechanical: 77.5% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 7.0 ± 3.5 years Mortality PPM was associated with increased long-term mortality (P < 0.05) EOA obtained from the literature Mean PTG No PPM vs PPM: 3.7 ± 1.2 mmHg vs 4.8 ± 1.5 mmHg (P < 0.001) Bouchard et al. (2010), Can J Cardiol, Canada [9] Retrospective cohort study (level 2b) n = 714 patients PPM: 10.3% Valve Mechanical: 100% PPM defined as iEOA <1.3 cm2/m2 Follow-up: 1871 ± 1178 days Mortality at 5 years No PPM vs PPM: 16.4% ± 1.7% vs 24.8% ± 6.2% (P = 0.007) EOA obtained from the literature Mortality at 10 years No PPM vs PPM: 32.6% ± 4.2% vs 46.1% ± 16.3% (P = 0.007) Lam et al. (2007), J Thorac Cardiovasc Surg, Canada [10] Retrospective cohort study (level 2b) n = 884 patients PPM: 31.6% Valve Bioprosthetic: 25.7% Mechanical: 74.3% PPM defined as iEOA ≤1.25 cm2/m2 Follow-up: 5.1 ± 4.1 years Mortality at 5 years No PPM vs PPM: 14% vs 22% (P = 0.05) EOA obtained from the literature or by the manufacturer Mortality at 10 years No PPM vs PPM: 25% vs 35% (P = 0.05) Jamieson et al. (2009), Ann Thorac Surg, Canada [11] Retrospective cohort study (level 2b) n = 2440 patients Moderate PPM: 69.5% Severe PPM: 16.3% Valve Bioprosthetic: 55.6% Mechanical: 44.4% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 6.1 ± 4.6 years Early mortality No PPM vs moderate PPM vs severe PPM: 5.5% vs 6.3% vs 8.5% (P = 0.182) EOA obtained from the literature or by echocardiography Late mortality No PPM vs moderate PPM vs severe PPM: 36.8% vs 32.8% vs 22.6% (P = NS) Incidence of preoperative PH No PPM vs moderate PPM vs severe PPM: 34.5% vs 37.4% vs 56.9% (P < 0.0001) Angeloni et al. (2013), Int J Cardiol, Italy [12] Retrospective cohort study (level 2b) n = 210 patients PPM: 42% Valve Bioprosthetic: 35.8% Mechanical: 64.2% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Follow-up: 27 months Mortality at follow-up No PPM vs PPM: 12.3% vs 12.5% (P = 0.83) EOA measured through CE Incidence of preoperative PH No PPM vs PPM: 70% vs 72% (P = 0.47) Incidence of PH at follow-up No PPM vs PPM: 24% vs 61% (P < 0.0001) Mean PTG No PPM vs PPM: 3.2 ± 2.5 mmHg vs 4.7 ± 1.1 mmHg (P < 0.0001) Mean postoperative SPAP No PPM vs PPM: 31 ± 6 mmHg vs 41 ± 9 mmHg (P < 0.0001) Pisano et al. (2016), J Heart Valve Dis, Italy [13] Retrospective cohort study (level 2b) n = 46 patients PPM: 25% Valve Bioprosthesis: 19.57% Mechanical: 80.43% PPM defined as iEOA <1.2 cm2/m2 Mean follow-up: 6.9 ± 1.8 years Mortality at follow-up No PPM vs PPM: 0% vs 0% EOA measured through CE Shi et al. (2011), Heart, Australia [14] Retrospective cohort study (level 2b) n = 1006 patients Moderate PPM: 52.8% Severe PPM: 13.2% Valve Bioprosthetic: 38% Mechanical: 62% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 7 years Mortality at 7 years No PPM vs moderate PPM vs severe PPM: 28% ± 4% vs 24% ± 2% vs 31% ± 10.3% (P = 0.76) EOA obtained from the literature Matsuura et al. (2011), Ann Thorac Cardiovasc Surg, Japan [15] Retrospective cohort study (level 2b) n = 212 patients PPM: 59% Valve Bioprosthetic: 34.9% Mechanical: 65.1% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 4.5 ± 8.4 years Late mortality No PPM vs PPM: 7% vs 9.6% (P = 0.1) EOA obtained from the literature or by echocardiography Peak PTG No PPM vs PPM: 9.8 ± 4.5 mmHg vs 11.9 ± 6.2 mmHg (P = 0.042) Mean PTG No PPM vs PPM: 3.6 ± 2.1 mmHg vs 4.0 ± 1.9 mmHg (P = 0.21) Sakamoto et al. (2010), Ann Thorac Cardiovasc Surg, Japan [16] Retrospective cohort study (level 2b) n = 84 patients PPM: 29.7% Valve Bioprosthetic: 10.7% Mechanical: 89.3% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 8.5 ± 3.9 years Freedom of cardiac death at: No PPM vs PPM: EOA measured through echocardiography 5 years 96% vs 100% 10 years 93% vs 95% 14 years 82% vs 95% (P > 0.05) Cho et al. (2016), Yonsei Med J, Korea [17] Retrospective cohort study (level 2b) n = 166 patients Moderate PPM: 48% Severe PPM: 14% Valve Bioprosthetic: 22% Mechanical: 78% No PPM defined as iEOA >1.2 cm2/m2 Moderate PPM defined as iEOA ≤1.2 to ≥0.9 cm2/m2 Severe PPM defined as iEOA <0.9 cm2/m2 Follow-up: 16 months Mean PTG No PPM vs PPM: 3.2 ± 1.1 mmHg vs 3.7 ± 1.2 mmHg (P < 0.021) In both groups, transmitral gradients remained below mild in terms of stenosis Mean postoperative SPAP No PPM vs moderate PPM: 25 ± 6 mmHg vs 28 ± 6 mmHg (P < 0.007) EOA obtained from the literature, manufacturer or by echocardiography Moderate PPM vs severe PPM: 28 ± 6 mmHg vs 33 ± 11 mmHg (P < 0.037) Cao et al. (2015), Med Sci Monit, China [18] Retrospective cohort study (level 2b) n = 493 patients PPM: 31.8% Valve Mechanical: 100% PPM defined as iEOA <1.2 cm2/m2 Follow-up: 3 years Mean PTG No PPM vs PPM: 14.89 ± 5.77 vs 25.34 ± 6.35 (P < 0.01) Severe postoperative mitral stenosis at follow-up even in those patients with no PPM EOA measured through CE Mean postoperative SPAP No PPM vs PPM: 43.17 ± 12.17 mmHg vs 53.29 ± 10.63 mmHg (P < 0.01) Li et al. (2005), J Am Coll Cardiol, Canada [19] Retrospective cohort study (level 2b) n = 56 patients PPM: 71.4% Valve Bioprosthetic: 16% Mechanical: 84% PH defined as SPAP >40 mmHg PPM defined as iEOA ≤1.2 cm2/m2 Incidence of preoperative PH No PPM vs PPM: 69% vs 66% (P > 0.05) Lower regression of PH was observed in patients with PPM EOA measured through CE Incidence of postoperative PH No PPM vs PPM: 19% vs 68% (P = 0.001) Peak PTG No PPM vs PPM: 8 ± 2 mmHg vs 12 ± 4 mmHg (P < 0.001) Mean PTG No PPM vs PPM: 3 ± 1 mmHg vs 4 ± 2 mmHg (P < 0.001) Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 46 ± 8 mmHg (P < 0.001) Ozyalcin et al. (2016), J Heart Valve Dis, Turkey [20] Retrospective cohort study (level 2b) n = 128 patients PPM: 35% Valve Mechanical: 100% PPM defined as iEOA <1.19 cm2/m2 Follow-up: 46 ± 9 months Mean postoperative SPAP No PPM vs PPM: 34 ± 8 mmHg vs 45 ± 7 mmHg (P < 0.0001) EOA measured through CE CE: continuity equation; iEOA: indexed effective orifice area; PH: pulmonary hypertension; PPM: patient–prosthesis mismatch; PTG: postoperative transmitral gradient; SPAP: systolic pulmonary artery pressure. RESULTS Ammannaya et al. [3] and Hwang et al. [4] showed that PPM was associated with a significant increase in long-term mortality and reduced freedom from cardiac death at 10 and 20 years following surgery when compared with patients with no PPM. In both studies, the difference in mortality and in freedom from cardiac death remained with propensity matching of the groups. Additionally, Hwang et al. [4] showed that PPM was associated with a significantly higher risk of death [hazard ratio (HR) 1.681, 95% confidence interval (CI) 1.139–2.482; P = 0.009] and a significantly poorer freedom from cardiac death (HR 1.673; 95% CI 1.012–2.765; P = 0.045). However, Ammannaya et al. [3] showed that PPM was associated with a significant increase in mean, peak transmitral gradients, postoperative systolic pulmonary artery pressure (SPAP) and increased incidence of postoperative PH. Borracci et al. [5] showed that severe PPM was associated with increased mortality in comparison with patients with no PPM or moderate PPM over the period of 5-year long follow-up (44.1% vs 10.5% vs 6.3%, P = 0.043, respectively). Also, the authors reported that the impact of severe PPM on mortality was even more pronounced when it was associated with severe postoperative PH. Aziz et al. [6] demonstrated that PPM was associated with a significant increase in long-term mortality when compared with patients with no PPM. Severe PPM, when compared with moderate PPM or no PPM, was associated with higher long-term mortality (59% ± 9% vs 48% ± 6% vs 44% ± 5%, P = 0.02). After stratifying by both age and the implanted valve type, although PPM did not impact long-term survival in younger patients (<65 years) after bioprosthetic MVR (P = 0.26), PPM impaired long-term survival in older bioprosthetic recipients (≥65 years; P = 0.05). On the other hand, moderate or severe PPM tended to impact long-term survival negatively after mechanical MVR in both age groups (<65 years P = 0.06 and ≥65 years P = 0.07). Magne et al. [7] studied the effect of PPM on both mean and peak transmitral gradient and postoperative SPAP and mortality. They reported that PPM was associated with significantly increased mortality over the period of 6 and 12 years following surgery, with a significant increase in peak and mean transmitral gradient as well as mean postoperative SPAP. A subgroup analysis showed that severe PPM was associated with worse outcomes when compared with moderate PPM. Additionally, severe PPM was found to be an independent predictor of mortality following MVR (HR 3.2, 95% CI 1.5–6.8; P = 0.003). Sato et al. [8], Bouchard et al. [9] and Lam et al. [10] showed that PPM was associated with increased long-term mortality when compared with patients with no PPM. In contrast, Jamieson et al. [11] showed that PPM was not associated with increased early and long-term mortality. However, preoperative PH, which is not an uncommon condition in patients undergoing MVR in the presence of moderate or severe PPM, was predictive of overall survival (Moderate PPM: HR 1.6, 95% CI 1.1–2.4; P = 0.02 and Severe PPM: HR 1.8, 95% CI 1.1–2.9; P = 0.03). Angeloni et al. [12] reported that there was no association between PPM and worse survival. The authors reported that PPM was associated with higher postoperative transmitral gradient and postoperative SPAP when compared to patients with no PPM. Incidence of PH remained increased at follow-up in patients with PPM (61% vs 24%, P < 0.0001). Pisano et al. [13], Shi et al. [14] and Matsuura et al. [15] showed that PPM was not associated with higher long-term mortality when compared to patients with no PPM. Sakamoto et al. [16] found no difference in the freedom from cardiac death between patients with no PPM and PPM (P > 0.05). Cho et al. [17], Cao et al. [18] and Li et al. [19] showed that PPM was associated with an increase in mean transmitral gradient and SPAP, also found by Ozyalcin et al. [20]. In addition, Li et al. [19] showed that PPM was also associated with increased incidence of postoperative PH. Overall, 8 studies with a total of 4812 patients showed that PPM has a significantly negative impact on long-term mortality, whereas 5 studies with a total of 1558 patients showed no effect on mortality. One study with a total of 2440 patients showed preoperative PH as the risk factor for increased mortality in the presence of moderate or severe PPM. Three studies with a total of 766 patients evaluated the effect of PPM on postoperative PH and showed that PPM was associated with significantly increased postoperative PH. The majority of the studies showed that PPM was associated with higher peak or mean transmitral gradient and SPAP. CLINICAL BOTTOM LINE PPM in patients undergoing MVR is associated with increased postoperative mean and peak transmitral gradient and higher postoperative SPAP. PPM may be associated with increased long-term mortality. Severe PPM is directly associated with increased long-term mortality when compared with moderate or no PPM. Evidence suggests that PPM is associated with increased incidence of postoperative PH. Conflict of interest: none declared. REFERENCES 1 Dunning J , Prendergast B , Mackway-Jones K. Towards evidence-based medicine in cardiothoracic surgery: best BETS . Interact CardioVasc Thorac Surg 2003 ; 2 : 405 – 9 . Google Scholar CrossRef Search ADS PubMed 2 Urso S , Sadaba R , Aldamiz-Echevarria G. Is patient-prosthesis mismatch an independent risk factor for early and mid-term overall mortality in adult patients undergoing aortic valve replacement? Interact CardioVasc Thorac Surg 2000 ; 9 : 510 – 8 . 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Impact of prosthesis–patient mismatch after mitral valve replacement: a multicentre analysis of early outcomes and mid-term survival . Heart 2011 ; 97 : 1074 – 81 . Google Scholar CrossRef Search ADS PubMed 15 Matsuura K , Mogi K , Aoki C , Takahara Y. Prosthesis-patient mismatch after mitral valve replacement stratified by referred and measured effective valve area . Ann Thorac Cardiovasc Surg 2011 ; 17 : 153 – 9 . Google Scholar CrossRef Search ADS PubMed 16 Sakamoto H , Watanabe Y. Does patient-prosthesis mismatch affect long-term results after mitral valve replacement? Ann Thorac Cardiovasc Surg 2010 ; 16 : 163 – 7 . Google Scholar PubMed 17 Cho IJ , Hong GR , Lee SH , Lee S , Chang BC , Shim CY et al. . Prosthesis-patient mismatch after mitral valve replacement: comparison of different methods of effective orifice area calculation . Yonsei Med J 2016 ; 57 : 328 – 36 . Google Scholar CrossRef Search ADS PubMed 18 Cao H , Qiu Z , Chen L , Chen D , Chen Q. Star GK bileaflet mechanical valve prosthesis-patient mismatch after mitral valve replacement: a Chinese multicenter clinical study . Med Sci Monit 2015 ; 21 : 2542 – 6 . Google Scholar CrossRef Search ADS PubMed 19 Li M , Dumesnil JG , Mathieu P , Pibarot P. Impact of valve prosthesis-patient mismatch on pulmonary arterial pressure after mitral valve replacement . J Am Coll Cardiol 2005 ; 45 : 1034 – 40 . Google Scholar CrossRef Search ADS PubMed 20 Ozyalcin S , Vural KM , Colak A. Mitral patient-prosthesis mismatch predicts suboptimal hemodynamic recovery after mitral valve replacement . J Heart Valve Dis 2016 ; 25 : 589 – 95 . Google Scholar PubMed © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices)

Journal

Interactive CardioVascular and Thoracic SurgeryOxford University Press

Published: Jan 22, 2018

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