Background: The reduction of RV function after cardiac surgery is a well-known phenomenon. It could persist up-to one year after the operation and often leads to an incomplete recovery at follow-up echocardiographic control. The aim of the present study is to analyze the impact of different modalities of pericardial incision (lateral versus anterior) and of myocardial protection protocols (Buckberg versus Custodiol) onto postoperative RV dynamic by relating two- and three-dimensional echocardiographic parameters in patients undergoing mitral valve repair through minimally invasive or traditional surgery approach. Methods: We have analyzed 44 consecutive patients with severe degenerative mitral regurgitation who underwent mitral reparation with different surgical approach and cardioplegia type: Group 1 (17 pts): sternotomy with Buckberg cardioplegia protocol; Group 2 (10 pts): sternotomy with Custodiol cardioplegia; Group 3 (17 pts): mini-invasive surgery with Custodiol cardioplegia. Two-dimensional transthoracic echocardiography was performed pre- and 6 months post-surgery to evaluate RV function by tricuspid annular plane systolic excursion (TAPSE). Results: All patients underwent successful and uneventful. A postoperative TAPSE reduction was found in all groups. However, mini-invasive patients experienced a significant reduced variation versus traditional surgery. Conclusions: Mini-invasive mitral repair, with lateral incision of pericardium, reduces postoperative TAPSE fall, while cardioplegia protocol fails to have an impact onto longitudinal RV function. In our study, the RV seems to experience a clinically irrelevant geometrical modification too, whose entity appears to be less evident in case of lateral pericardial approach. These results could strengthen the use of minimally invasive approach also to preserve RV function. Keywords: Mitral valve, Valve repair, Minimally invasive surgery, Right ventricle, Cardioplegia, Echocardiography Background basal values is often incomplete and an echocardiographic Right ventricular function is widely known as a deter- dysfunction can persist even at one year after surgery . minant of exercise capacity and as significant prognostic Physiopathology of right ventricle behavior following value in the evaluation of surgical outcome [1, 2]. cardiac surgery is a largely debated issue and several During and immediately after cardiac surgery, it is known hypotheses have been suggested: 1) myocardial that there is a decrease of two-dimensional indexes of hypothermia ; 2) cardiopulmonary bypass use ; right ventricle systolic performance [3–5]. Recovery to 3) pericardial adhesions . Pericardial opening need  and modality of cardioplegia delivery, retrograde cardiac protection seems to be less effective in pre- serving right ventricle function,  appear to be * Correspondence: firstname.lastname@example.org 1 mainly involved. Department of Cardiac Surgery, Centro Cardiologico Monzino IRCCS, University of Milan, Via Parea, 4, 20138 Milan, Italy Two-dimensional echocardiography represents the ref- Heart Center, University Hospital of Zürich, University of Zürich, Zürich, CH, erence method for cardiac surgery patients’ follow up; Switzerland © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Zanobini et al. Journal of Cardiothoracic Surgery (2018) 13:55 Page 2 of 8 however, regarding the evaluation of right ventricle per- We retrospectively analyze data of 44 consecutive pa- formance, it has important limitations due to its particu- tients (mean age 54 ± 12 years; 34 males/10 females) lar anatomy. The recent introduction of 3-dimensional with severe mitral regurgitation related to degenerative echocardiographic images allows a more complete dysfunction due to mitral valve prolapse who underwent evaluation of right ventricle contraction, showing that mitral valve reparation at our Center by the same Sur- two-dimensional indexes decrease failed to be accom- geon. We subdivided them in 3 groups according to sur- panied by concomitant parallel right ventricle three-di- gical approach and cardioplegia type (Fig. 1): mensional functional changes . Unfortunately, 3D echocardiograms can be performed 1. Group 1: traditional sternotomy operation with only by highly specialized experienced operators. Indeed, Buckberg cardioplegia protocol (blood mixed 2D measurements like tricuspid annular plane systolic antegrade-retrograde solution) – 17 patients excursion (TAPSE) is still largely used in right ventricu- 2. Group 2: traditional sternotomy operation with lar evaluation. Custodiol cardioplegia (crystalloid antegrade The aim of the present study is to evaluate the impact administration) – 10 patients of the type of pericardial incision (lateral versus anterior) 3. Group 3: mini-invasive surgery (4 cm right antero- in combination of different myocardial protection lateral thoracotomy) with Custodiol cardioplegia protocols onto postoperative right ventricular systolic (crystalloid antegrade administration) – 17 patients function in order to further investigate the superiority of minimally invasive approach in mitral valve surgery. Mini-invasive mitral surgery tends to be performed with single shot cardioplegia protocol, like Custodiol, Methods while Buckberg protocol seems to be more protective Population and study protocol and versatile for traditional surgery. The design of the All patients were enrolled in our Center and operated by study permits to investigate independently surgical ap- the same surgeon. Written informed consent to partici- proach and cardioplegia making a comparison between pate in this observational study, which was approved by groups with same pericardial access (group 1 and 2) but Centro Cardiologico Monzino Institutional Review different myocardial protection and between groups with Board, was obtained from all patients. The study proto- same cardioplegia protocol but different incision of the col conforms to the ethical guidelines of the Declaration pericardium (group 2 and 3). of Helsinki as reflected in a priori approval by the insti- Clinical and echocardiographic baseline patients’ char- tution’s human research committee. acteristics are shown in Table 1. Composition of cardio- To achieve the aim of this study, we compared 2- and plegic solutions is reported in Table 2. 3-dimensional echocardiographic parameters in patients Exclusion criteria were persistent or paroxysmal atrial undergoing minimally invasive or traditional (full ster- fibrillation, urgent intervention with hemodynamic in- notomy) mitral valve repair (MVR) focusing onto the stability, poor echocardiographic acoustic apical window, impact of pericardial incision and cardioplegia protocol. tricuspid regurgitation major than 1 degree (scale 1 to 4), Fig. 1 Design of the study Zanobini et al. Journal of Cardiothoracic Surgery (2018) 13:55 Page 3 of 8 Table 1 Clinical and echocardiographic groups’ baseline Surgical procedures characteristics Traditional MVR patients (group 1 and 2) underwent Group 1 Group 2 Group 3 P value complete median sternotomy and anterior opening of the (n = 17) (n = 10) (n = 17) pericardium with a reversed T incision. Standard cardio- Age, y 54.8 ± 11.9 59.2 ± 10.2 50.9 ± 12.2 0.14 pulmonary bypass (CBP) was implanted with ascending Male, n (%) 13 (76%) 7 (70%) 14 (82%) 0.18 aortic cannulation and bicaval venous cannulation. BSA (m ) 1.9 ± 0.2 1.8 ± 0.2 1.8 ± 0.1 0.32 * In Group 1 Buckberg cardioplegia was adopted, EuroSCORE 2 0.98% 0.96% 0.95% 0.45 consisting in a three-phases myocardial protection LVEF 60.4 ± 6.4 58.2 ± 4.1 64.5 ± 4.7 0.32 protocol: TAPSE (mm) 24.5 ± 4.8 27.4 ± 5.3 23.5 ± 4 0.17 SPAP (mmHg) 33.9 ± 4.8 32.3 ± 5.1 34.9 ± 2.7 0.83 RVEF (3D) 62.2 ± 8.9 60.5 ± 8.2 58.5 ± 6.1 0.56 1. Cold induction: delivery of cold cardioplegic solution (8–12 °C) antegrade and retrograde for 2 min each RVSV (3D) 68.3 ± 23.9 54.1 ± 18.8 68 ± 13.1 0.21 Ɨ until complete cardioplegic arrest was achieved (flow RVESV (3D) 43.4 ± 22.5 34.7 ± 11.7 48.5 ± 11.6 0.34 200 ml/min, in hypertrophied hearts increase to RVEDV (3D) 111.7 ± 42.8 88.8 ± 26.1 116.5 ± 19.8 0.18 300 ml/min) MVP Type 2. Reinfusions with cold blood cardioplegia: during aortic Posterior leaflet 17 9 17 cross-clamping, multidose cold blood cardioplegia was prolapse applied at intervals of 20 min to maintain cardioplegic Anterior leaflet 21 1 arrest and myocardial hypothermia. Infusions were de- prolapse livered retrograde for 1 min (flow 200 ml/min) *EuroSCORE 2 denotes the European System for Cardiac Operative Risk 3. Warm terminal reperfusion (“hot shot”): Evaluation (2nd version) p = 0.04 Group 2 versus 3 normothermic substrate-enriched blood cardiople- p = 0.03 Group 2 versus 3 gia was applied before aortic unclamping. The warm BSA Indicates body surface area, LVEF Left ventricular ejection fraction, TAPSE reperfusate was delivered via coronary sinus for Tricuspid annular plane systolic excursion, SPAP Systolic pulmonary arterial pressure, RVEF Right ventricular ejection fraction, RVSV Right ventricular stroke 1 min and followed by a brief (20–30 s) retrograde volume, RVESV Right ventricular end-systolic volume, RVEDV Right ventricular administration of normothermic blood . end-diastolic volume, MVP Mitral valve prolapse concomitant surgery procedures or mitral valve replace- In Group 2 Custodiol protocol protection (single ante- ment, major pulmonary diseases justifying a right ven- grade injection of crystalloid intracellular cold cardiople- tricular dysfunction or pulmonary hypertension, previous gia in 6–8 min) was employed. cardiac surgery and preoperative reduced LV function Minimally invasive mitral valve repair (Group 3) was (Ejection fraction < 40%). Two-dimensional (2D-) and performed through a small (5 cm) right antero-lateral three-dimensional (3D-) transthoracic echocardiography thoracotomy and with a lateral supra-phrenic pericardial (TTE) was performed preoperative (24–48 h before incision. Peripheral CBP was implanted using femoral surgery) and 6 months after surgical operation. vessels for arterial and venous cannulation. Similarly to Group 2, a single antegrade dose of Custodiol cardiople- gia was administered. Table 2 Composition of cardioplegic solutions used in the study All interventions were performed in moderate Ingredient Buckberg cold Buckberg cold Buckberg Custodiol hypothermia (32 °C) with a direct left atriotomy through induction 4.1 maintenance 4.1 “hot shot” Waterstone’s groove. Depending on patient’s mitral alter- Na 140 140 140 15 ation we used different surgical repairing techniques al- K 20 10 8 9 ways supported by annuloplasty with a prosthetic ring ++ Mg 13 9 6 4 implantation (Table 3). In each group the pericardium ++ Ca –– – 0.015 was completely re-closed with a continuous suture. Hystidine –– – 198 Echocardiographic measurements Tryptophan –– – 2 We performed a complete standard M-mode and two- Ketoglutarate–– – 1 dimensional echocardiographic examinations using a Mannitol –– – 30 Philips ultrasound system (iE33, Andover, MA, USA) Glucose 6 6 8 – and an S5–1 sector array probe. LV end-diastolic and pH 7.2 7.4 7.5 7.02–7.2 end-systolic volumes, as well as biplane ejection fraction All ingredients are expressed in mmol/L were measured in apical four- and two chamber views Zanobini et al. Journal of Cardiothoracic Surgery (2018) 13:55 Page 4 of 8 Table 3 Intraoperative groups’ characteristics A between-groups comparison examining the impact of pericardial approach and type of cardioplegia on right Group 1 Group 2 Group 3 P value (n = 17) (n = 10) (n = 17) ventricular function over time was made with an analysis CPB time (min) 113 ± 17 105 ± 18 131 ± 23 0.21 of variance and co-variance (ANOVA test) adjusted for patients’ age, sex, body surface area and right ventricular Cross-clamp time (min) 95 ± 13 93 ± 12 112 ± 12 0.24 features basal values. Complete prosthetic 3 2 2 0.32 semi-rigid ring A p value < 0.05 was considered as statistically significant. Incomplete band 14 8 15 0.25 Results Annular plication 1 0 0 0.43 All enrolled patients underwent mitral valve repair sur- Quadrangular resection 6 4 7 0.44 gery without significant complications. After six month Triangular resection 9 5 9 0.28 after surgery (185 ± 23 days), all cases had residual mitral Sliding-plasty 5 4 6 0.12 regurgitation inferior to 1 degree (scale 1 to 4). At least Artificial chordae 2 1 1 0.23 one good quality, three-dimensional right ventricle data- positioning set was acquired in all patients before surgery and six Papillary muscle 1 0 0 0.34 months after the surgery. Tables 4 and 5 and Panel A plication (Fig. 2) shows the mean values of the two-dimensional CPB Indicates cardio-pulmonary bypass and three-dimensional parameters for each step of the study in both groups. with the area–length method. Systolic pulmonary arterial Table 4 Two-dimensional and three-dimensional echocardio- pressure was non-invasively acquired using Doppler graphic parameters measured at pre- and 6 months post-surgery echo method from the systolic right ventricle–right atrial Variable Pre-surgery Sixth month P Within Group gradient, calculated from the systolic trans-tricuspid TAPSE (mm) regurgitant flow peak velocity by the modified Bernoulli equation. Right atrial (RA) pressure was derived by Group 1 24.5 ± 4.8 14.9 ± 3 < 0.0001 means of the inferior vena cava (IVC) collapsibility index Group 2 27.4 ± 5.3 19.3 ± 4.2 0.0003 measured from the subcostal view . To estimate tri- Group 3 23.5 ± 4 21.5 ± 4.1 0.013 cuspid annular plane systolic excursion (TAPSE), defined SPAP (mmHg) as the difference in the displacement of the right ven- Group 1 33.9 ± 4.8 25.7 ± 2.9 < 0.0001 tricle base from end-diastole to end-systole, from the ap- Group 2 32.3 ± 5.1 28.3 ± 6.5 0.054 ical four-chamber view, the M-mode cursor was positioned at the junction of the tricuspid valvular plane Group 3 34.9 ± 8.1 25.2 ± 3.1 0.049 with the right ventricle free [14, 15]. RVEDV (ml) 3D- Real-time TTE was performed during same echo- Group 1 111.7 ± 42.8 93.1 ± 26.2 0.016 cardiographic session utilizing an X3–1 matrix array Group 2 88.8 ± 26.1 72.2 ± 21.3 0.002 probe. The 3D-measurement were acquired using ‘full Group 3 116.5 ± 19.8 105.2 ± 20.6 0.039 volume’ mode from the apical view, adapted to improve RVESV (ml) the visualization of the right ventricular chamber. We registered Two datasets for each patient. To perform off- Group 1 43.4 ± 22.5 39.2 ± 13.6 0.244 line post-processing and three-dimensional reconstruc- Group 2 34.7 ± 11.7 29.2 ± 9.2 0.048 tion we used a commercially available dedicated system Group 3 48.5 ± 11.6 41 ± 9 0.005 (Echo View, Tom Tec Imaging Inc., Munich, Germany) 3D RVEF (%) equipped with a four-dimensional right ventricle analysis Group 1 62.2 ± 8.9 58.2 ± 5.4 0.021 software . Group 2 60.5 ± 8.2 59.5 ± 6.9 0.579 Statistical analysis Group 3 58.5 ± 6.1 60.7 ± 6.8 0.207 Data were managed in Microsoft Excel 2016 and ana- 3D RVSV (ml) lyzed with SPSS 22.0 software (SPSS, Inc., Chicago, IL) Group 1 68.3 ± 23.9 53.9 ± 13.9 0.004 and SAS system (SAS Institute Inc., Cary, NC). Each Group 2 54.1 ± 18.8 43 ± 14.1 0.0039 echocardiographic parameter was evaluated pre- and Group 3 68 ± 13.1 64.1 ± 15.9 0.349 6 months post-surgery. Continuous variables were pre- TAPSE Indicates tricuspid annular plane systolic excursion, SPAP Systolic sented as mean ± SD and compared with an unpaired t- pulmonary arterial pressure, RVEDV Right ventricular end-diastolic volume, test, while categorical data were expressed as percent- RVESV Right ventricular end-systolic volume, RVEF Right ventricular ejection ages or numbers and compared with ʎ test. fraction, RVSV Right ventricular stroke volume Zanobini et al. Journal of Cardiothoracic Surgery (2018) 13:55 Page 5 of 8 Table 5 Inter-group comparison of two-dimensional and three-dimensional echocardiographic parameters variations (6 months post-surgery versus pre-operative values) Delta variable Group 1 Group 2 Group 3 P Group 1 vs 3 P Group 1 vs 2 P Group 3 vs 2 TAPSE(mm) −9.5 −8.1 −2 < 0.0001 0.12 0.008 SPAP(mmHg) −8.1 −4 −9.7 0.66 0.86 0.65 RVEDV (ml) −18.6 −16.5 −11.3 0.54 0.93 0.51 RVESV (ml) −4.2 −5.5 −7.4 0.49 0.69 0.91 3D RVEF (%) −3.9 −0.9 2.2 0.04 0.22 0.74 3D RVSV(ml) −14.4 −11.1 −3.9 0.18 0.66 0.45 2D LVEF (%) −7.6 −8.1 −3.8 0.08 0.84 0.19 TAPSE indicates tricuspid annular plane systolic excursion, SPAP systolic pulmonary arterial pressure, RVEDV right ventricular end-diastolic volume, RVESV right ventricular end-systolic volume, RVEF right ventricular ejection fraction, RVSV right ventricular stroke volume, LVEF left ventricular ejection fraction Preoperative left and right ventricular function were in between mini-invasive versus sternotomy-Buckberg pa- normal range for all patients. Basal TAPSE was slightly tients (p = 0.04). Similarly, right ventricular stroke vol- greater, but did not reach statistical significance, in trad- ume diminished after surgery in all patients without itional surgery (Group 1 and 2, respectively 24.5 and 27. significant inter-group differences. 4 versus 23.5 for mini-invasive patients; p = 0.17). All the three groups had similar preoperative 3D right ven- Discussion tricular function and cross-clamping/extracorporeal cir- The importance of RV function as an important physio- culation time. pathology element in many different cardiovascular dis- ease is a well-known phenomenon and it is an already Two-dimensional measurements validated prognostic index after cardiac surgery. In the Postoperative TAPSE fall was found in each group past, obtaining an accurate postoperative evaluation of (Table 4), but mini-invasive patients experienced a RV function has been made difficult by its complex anat- less marked variation (group 3: 21.5 ± 4.1 post- versus omy and morphology. This problem was solved by the 23.5 ± 4 pre-; p = 0.01) compared to traditional assessment of tricuspid annulus movement with 2D- surgery (Group 1 14.9 ± 3 post versus 24.5 ± 4.8 pre; Echocardiographic analysis that has been proved to be p < 0.0001; Group 2 19.3 ± 4.2 post versus 27.4 ± 5.3 accurate, feasible, simple and reproducible in both pre; p = 0.0003). The difference remained statistically normal and pathological patients . The introduc- significant after adjustment for patients’ age, sex, body tion of 3D-Echocardiography has permitted a big surfaceareaand basalTAPSE (Group 3versus1 p < step forward in the evaluation of RV volume and 0.0001 and Group 3 versus 2 p = 0.008). function throughout the cardiac cycle [18, 19] Systolic pulmonary arterial pressure showed a similar permitting to calculate the right ventricular ejection postoperative fall in each group. fraction (RV-EF) that represents the global perform- Left ventricular volumes and ejection fraction de- ance of the ventricle. The main limitation 3D- creased after surgery in a similar manner in all patients. echocardiography is that is a technology usually available only in high-experienced center with skilled Three-dimensional measurements operators while 2D- TAPSE evaluation is an easy In Sterno-Buckberg patients (Group 1) end-systolic size- measurement for every echocardiographist. decreasing trend failed to reach statistical significance. Several studies report a reduction of TAPSE after car- However, in the other two groups (groups 2 and 3, Cus- diac surgery for congenital and acquired diseases [6, 20] todiol), both end-diastolic and end-systolic right ven- without univocal explanation. Observing a post- tricular volumes significantly diminished after surgery. operative TAPSE decrease, without variation in left ven- Any inter-group size changes comparison showed a sig- tricle function, has driven to interpret it as a simple nificant difference (Table 4). modification with modest clinical impact. Many hypoth- In mini-invasive patients (group 3), right ventricular esis have been presented in order to clarify this loss in ejection fraction slightly augmented after surgery (60.7 ± RV performance measured at 2D-TTE, including cardio- 6.8 post versus 58.5 ± 6.1 pre; p = 0.2), while, in Group 1 pulmonary bypass use [8, 21], geometrical changes of decreased (58.2 ± 5.4 post versus 62.2 ± 8.9 pre; p =0. the right ventricular chamber (in association with inter- 02). In contrast, no significance difference was found in ventricular septal paradoxical motion , intra- Group 2 (59.5 ± 6.9 post versus 60.5 ± 8.2 pre; p = 0.58). operative ischemia, right atrial injury due to cannulation In addition, this variation was significantly different procedure , poor myocardial protection , and Zanobini et al. Journal of Cardiothoracic Surgery (2018) 13:55 Page 6 of 8 Fig. 2 PANEL a - Mean tricuspid annular plane systolic excursion (TAPSE) and 95% confidence intervals (CIs) measured preoperatively and at 6 months postoperatively. * Between-groups comparison. p < 0.05 vs preoperative; PANEL b - Mean three-dimensional right ventricular ejection fraction (3D RVEF) and 95% confidence intervals (CIs) measured preoperatively and at 6 months postoperatively. * Between-groups comparison p < 0.05 vs preoperative; Panel c - Mean three-dimensional right ventricular stroke volume (3D RVSV) and 95% confidence intervals (CIs) measured preoperatively and at 6 months postoperatively. p < 0.05 vs preoperative extra myocardial causes (pericardial disruption, changes traditional and mini-invasive surgery is represented by in Fossa Ovalis and post-operative adherence of the right the use of single shot cardioplegia protocol in mini- ventricle to the thoracic wall, 9). The role of pericardial MVR. To eliminate this bias and to evaluate myocardial injury has also been highlighted in our precedent study protection impact on TAPSE we designed this three . One of the major confounding factors comparing groups study. Zanobini et al. Journal of Cardiothoracic Surgery (2018) 13:55 Page 7 of 8 To minimize all other possible confounding factors trend, which was less accentuated (or even inversed when and to eliminate inter-operators difference, we acquired talking about right ventricular ejection fraction) in mini- data only from patient underwent MVR by the same invasive group. In other words, it seems that, in our study, surgeon and who had pre- and postoperative TTE by the right ventricle undergoes a kind of geometrical modifi- one dedicated echocardiographist. Surgical valve repair cations too, which appear to be less affected by a lateral technique doesn’t significantly differ within the 3 groups pericardial approach. Nevertheless, in our opinion, such (Table 3) as well as the type of implanted prosthetic tendency (which could be interpreted as clinically negli- rings. Cross-clamping time and cardiopulmonary bypass gible since included in the normal range of measure vari- time resulted comparable in all groups. The pericardial ability) is partially different from what previously reported opening was entirely closed with a running suture in all . A prudent interpretation is justified by various consid- patients. erations: 1) the increasing trend of right ventricular ejec- TAPSE reduction was observed in all groups, but it tion fraction in mini-invasive group is not confirmed by a has been significantly less marked in mini-invasive parallel stroke volume time-course; 2) the inter-group surgery group who underwent mini-anterolateral thora- evaluation failed to show a statistically significant differ- cotomy with supraphrenic lateral pericardial incision ence when comparing Group 3 vs Group 2 (thus perhaps and Custodiol cardioplegia. Evaluating different cardio- suggesting a role played by cardioplegia too); 3) the intra- plegia protocol with same surgical approach (group 1 vs. group three-dimensional variables variations were not sig- 2) we did not find any significant differences. 3D- nificant in all groups. echocardiographic RV postoperative volume resulted Basing on these reasons, we believe that deeper inves- comparable within the 3 groups. A slightly augmented tigations involving a greater patients’ population and a RV ejection fraction was observed after mini-invasive longer follow up time (which could elucidate that such surgery (group 3) while it decreased in patients under- trend was only a temporary phenomenon, as also went traditional median sternotomy despite the different pointed out by postoperative right ventricular ejection cardioplegia protocol (group 1 Buckberg, group 2 Custo- fraction fluctuations described by Tamborini et al.,3) are diol). According to these results, only different surgical required before drawing definitive conclusions. approach impact RV function, in particular, lateral peri- We studied a relative small number of cases. Despite cardial incision used in mini-invasive surgery is able to this limitation and even though our data should be con- significantly limit right-ventricle longitudinal post- firmed in a larger population, statistical analysis clearly operative function decrease while the different type of defined significant changes and differences in the three cardioplegia protocol has no relevant effect on TAPSE. groups, being able to highlight how different surgical To explain these findings more than a hypothesis can protocols resulted in diverse right ventricular function be provided. The first one could be that anterior pericar- postoperative trends. dial incision modifies a portion of pericardium directly connected with the RV free wall while lateral opening, in Study limitations the face of interatrial groove, does not interfere with RV Main study limitation is represented by limited number motility. As we previously proposed , another expli- of patients of the cohort analyzed and as well as the cation could be linked to the shape itself of anterior needed of longer echocardiographic follow-up. Larger pericardial incision. It consisted in a reversed T incision population, different type of cardioplegia (Del Nido, St. with a double opening line along the diaphragm that Thomas, etc..) should be investigated. could modify the relationship between this muscle and the inferior RV wall leading to possible variations in lon- Conclusions gitudinal right ventricular contractile pattern and conse- Minimally invasive mitral repair with lateral pericardial quently to postoperative TAPSE fall. The different opening reduces postoperative TAPSE fall while cardio- surgical repair techniques and prosthetic rings used to plegia protocol fails to have an impact onto longitudinal restore mitral valve competency and to assure long-term RV function. In our study, the right ventricle seems to durability should not influence inter-group differences show a clinically irrelevant geometrical modification too, due to the homogenous distribution of them in the 3 whose entity appears to be less evident in case of lateral groups. Different kind of resection or ring did not reach pericardial approach. These results could strengthen the significant statistic difference within the study popula- use of minimally invasive approach also to preserve right tion (Table 3). ventricle function. An additional important observation from this study is Abbreviations that, in parallel to the attended impairment of right ven- CBP: Cardiopulmonary bypass; IVC: Inferior vena cava; MVR: Mitral valve tricle long-axis function, also three-dimensional global repair; TAPSE: Tricuspid annular plane systolic excursion; TTE: Transthoracic systolic indexes showed a postoperative slight decreasing echocardiography Zanobini et al. Journal of Cardiothoracic Surgery (2018) 13:55 Page 8 of 8 Authors’ contribution 15. Miller D, Farah MG, Keith F, Fox K, Schluchter M, Hoit BD. The relation MS, MZ have contribute equally to this work. 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Journal of Cardiothoracic Surgery
– Springer Journals
Published: Jun 5, 2018