Comparison of aortic annulus dimensions after aortic valve neocuspidization with those of normal aortic valve using transthoracic echocardiography

Comparison of aortic annulus dimensions after aortic valve neocuspidization with those of normal... Abstract OBJECTIVES This study aimed to elucidate the physiological feasibility of aortic valve neocuspidization (AVNeo) by comparing the aortic annulus dimensions between patients after AVNeo and patients with normal aortic valves. METHODS From December 2010 to October 2017, we performed AVNeo for various aortic valve pathologies in 147 patients. Of these patients, the aortic annulus dimensions were measured in 25 patients who underwent AVNeo for aortic valve disease as follow-up examination and compared with those measured in 15 patients who had normal aortic valves. Measurements were recorded using electrocardiography-gated transthoracic echocardiography. RESULTS No significant differences in the aortic annulus dimensions were observed between the patients who had undergone AVNeo and those who had normal aortic valves. In a cardiac cycle, the annulus area in the systolic phase was consistently larger than that in the diastolic phase, which was a physiological condition. CONCLUSIONS The movement of the aortic annulus after AVNeo is comparable with that of the aortic annulus of a normal aortic valve. Thus, AVNeo can be regarded as a more physiological operation in that it maintains the characteristics of the aortic valve similar to those of a normal aortic valve. Aortic valve neocuspidization, Aortic annulus dimension, Transthoracic echocardiography INTRODUCTION Aortic valve reconstruction with glutaraldehyde-treated autologous pericardium for patients with aortic valve disease was started by Duran et al. [1] in 1988. Since then, the long-term results after a 16-year follow-up were reported [2]. Subsequently, Ozaki et al. [3] developed aortic valve reconstruction with an autologous pericardium which be came known as aortic valve neocuspidization (AVNeo). To date, the standard operation for aortic valve disease has been aortic valve replacement (AVR) using a prosthetic valve. Both mechanical and bioprosthetic valves have a stent structure for suturing and fixing to the aortic valve annulus, which in turn inhibits the aortic annulus movement, decreases the postoperative aortic valve area, increases the pressure gradient and occasionally increases the prosthesis–patient mismatch. We have performed AVNeo for various aortic valve diseases since 2010. In this study, we elucidated whether AVNeo is physiologically acceptable by evaluating the aortic annulus movement in a cardiac cycle using transthoracic echocardiography (TTE). METHODS Characteristics of patients and study design From December 2010 to October 2017, we performed AVNeo for various aortic valve pathologies. For the AVNeo group, we retrospectively evaluated and reviewed 25 random patients (11 men and 14 women) who underwent AVNeo. Their mean age was 73.9 ± 14.4 (44–92) years. For the normal aortic valve group, 8 men and 7 women were included, and their mean age was 60.7 ± 24.5 (16–89) years. The characteristics of the patients are shown in Table 1. In the normal aortic valve group, the reasons for using TTE were as follows: preoperative evaluation for gastroenteric surgery (7), signs of arrhythmia (6) and leg oedema (2). Table 1: Characteristics of patients   AVNeo (n = 25)  Normal (n = 15)  P-value  AS, n (%)  17 (68)  0 (0)  NA  AR, n (%)  8 (32)  0 (0)  NA  Age (years), mean ± SD  73.9 ± 18.8  60.7 ± 24.5  0.038  Male gender, n (%)  11 (44)  8 (53)  0.57  BSA (m2), mean ± SD  1.5 ± 0.2  1.6 ± 0.2  0.073  Hypertension, n (%)  18 (72)  11 (73)  0.92  Diabetes, n (%)  5 (20)  3 (20)  0.74  Dyslipidaemia, n (%)  14 (56)  7 (47)  0.57  Chronic kidney disease, n (%)  12 (48)  3 (20)  0.077  Ischaemic heart disease, n (%)  4 (16)  4 (27)  0.41  Cerebral infarction, n (%)  2 (8)  1 (7)  0.88    AVNeo (n = 25)  Normal (n = 15)  P-value  AS, n (%)  17 (68)  0 (0)  NA  AR, n (%)  8 (32)  0 (0)  NA  Age (years), mean ± SD  73.9 ± 18.8  60.7 ± 24.5  0.038  Male gender, n (%)  11 (44)  8 (53)  0.57  BSA (m2), mean ± SD  1.5 ± 0.2  1.6 ± 0.2  0.073  Hypertension, n (%)  18 (72)  11 (73)  0.92  Diabetes, n (%)  5 (20)  3 (20)  0.74  Dyslipidaemia, n (%)  14 (56)  7 (47)  0.57  Chronic kidney disease, n (%)  12 (48)  3 (20)  0.077  Ischaemic heart disease, n (%)  4 (16)  4 (27)  0.41  Cerebral infarction, n (%)  2 (8)  1 (7)  0.88  AR: aortic valve regurgitation; AS: aortic valve stenosis; BSA: body surface area; NA: not applicable; SD: standard deviation. Table 1: Characteristics of patients   AVNeo (n = 25)  Normal (n = 15)  P-value  AS, n (%)  17 (68)  0 (0)  NA  AR, n (%)  8 (32)  0 (0)  NA  Age (years), mean ± SD  73.9 ± 18.8  60.7 ± 24.5  0.038  Male gender, n (%)  11 (44)  8 (53)  0.57  BSA (m2), mean ± SD  1.5 ± 0.2  1.6 ± 0.2  0.073  Hypertension, n (%)  18 (72)  11 (73)  0.92  Diabetes, n (%)  5 (20)  3 (20)  0.74  Dyslipidaemia, n (%)  14 (56)  7 (47)  0.57  Chronic kidney disease, n (%)  12 (48)  3 (20)  0.077  Ischaemic heart disease, n (%)  4 (16)  4 (27)  0.41  Cerebral infarction, n (%)  2 (8)  1 (7)  0.88    AVNeo (n = 25)  Normal (n = 15)  P-value  AS, n (%)  17 (68)  0 (0)  NA  AR, n (%)  8 (32)  0 (0)  NA  Age (years), mean ± SD  73.9 ± 18.8  60.7 ± 24.5  0.038  Male gender, n (%)  11 (44)  8 (53)  0.57  BSA (m2), mean ± SD  1.5 ± 0.2  1.6 ± 0.2  0.073  Hypertension, n (%)  18 (72)  11 (73)  0.92  Diabetes, n (%)  5 (20)  3 (20)  0.74  Dyslipidaemia, n (%)  14 (56)  7 (47)  0.57  Chronic kidney disease, n (%)  12 (48)  3 (20)  0.077  Ischaemic heart disease, n (%)  4 (16)  4 (27)  0.41  Cerebral infarction, n (%)  2 (8)  1 (7)  0.88  AR: aortic valve regurgitation; AS: aortic valve stenosis; BSA: body surface area; NA: not applicable; SD: standard deviation. Transthoracic echocardiography examination Electrocardiography-gated TTE was performed using the ultrasound units SSA-790A (AplioXG™) and TUS-400 (Aplio400) (both from Toshiba Medical Systems Co., Otawara, Japan). In the AVNeo group, the patients underwent TTE as a routine follow-up after AVNeo. In the normal aortic valve group, 15 patients with no aortic valve disease were selected randomly during the study period. Measurements of the aortic annulus and its perimeter during the cardiac cycle were performed by skilled echocardiographers using electrocardiography. Other echocardiographic data such as ejection fraction and left atrial diameter were also obtained. The differences between the 2 groups are shown in Table 2. The annulus areas, perimeters and their changes are listed in Table 3. When comparing the areas and perimeters of the aortic annulus to minimize the effects of physique, the aortic annulus area was divided by body surface area. Table 2: Comparison of transthoracic echocardiogram data between the AVNeo group and the normal valve group   AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  EF (%)  64.6 ± 5.5  65.7 ± 5.8  0.54  AOD (mm)  26.7 ± 5.6  25.3 ± 3.3  0.38  LAD (mm)  37.2 ± 5.5  35.4 ± 3.5  0.27  IVSTd (mm)  11.0 ± 1.4  9.7 ± 1.3  0.006  PWTd (mm)  10.6 ± 1.2  9.8 ± 1.3  0.056  LVDd (mm)  41.6 ± 9.0  44.7 ± 4.9  0.22  LVDs (mm)  28.6 ± 5.7  28.2 ± 3.7  0.81  FS (%)  34.6 ± 4.6  36.9 ± 4.9  0.14    AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  EF (%)  64.6 ± 5.5  65.7 ± 5.8  0.54  AOD (mm)  26.7 ± 5.6  25.3 ± 3.3  0.38  LAD (mm)  37.2 ± 5.5  35.4 ± 3.5  0.27  IVSTd (mm)  11.0 ± 1.4  9.7 ± 1.3  0.006  PWTd (mm)  10.6 ± 1.2  9.8 ± 1.3  0.056  LVDd (mm)  41.6 ± 9.0  44.7 ± 4.9  0.22  LVDs (mm)  28.6 ± 5.7  28.2 ± 3.7  0.81  FS (%)  34.6 ± 4.6  36.9 ± 4.9  0.14  AOD: aortic diameter; EF: ejection fraction; LAD: left atrial dimension; IVSTd: interventricular septal thickness diameter at the end diastole; PWTd: posterior wall thickness diameter; LVDd: left ventricular internal dimension in diastole; LVDs: left ventricular diameter in end systole; FS: fractional shortening; SD: standard deviation. Table 2: Comparison of transthoracic echocardiogram data between the AVNeo group and the normal valve group   AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  EF (%)  64.6 ± 5.5  65.7 ± 5.8  0.54  AOD (mm)  26.7 ± 5.6  25.3 ± 3.3  0.38  LAD (mm)  37.2 ± 5.5  35.4 ± 3.5  0.27  IVSTd (mm)  11.0 ± 1.4  9.7 ± 1.3  0.006  PWTd (mm)  10.6 ± 1.2  9.8 ± 1.3  0.056  LVDd (mm)  41.6 ± 9.0  44.7 ± 4.9  0.22  LVDs (mm)  28.6 ± 5.7  28.2 ± 3.7  0.81  FS (%)  34.6 ± 4.6  36.9 ± 4.9  0.14    AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  EF (%)  64.6 ± 5.5  65.7 ± 5.8  0.54  AOD (mm)  26.7 ± 5.6  25.3 ± 3.3  0.38  LAD (mm)  37.2 ± 5.5  35.4 ± 3.5  0.27  IVSTd (mm)  11.0 ± 1.4  9.7 ± 1.3  0.006  PWTd (mm)  10.6 ± 1.2  9.8 ± 1.3  0.056  LVDd (mm)  41.6 ± 9.0  44.7 ± 4.9  0.22  LVDs (mm)  28.6 ± 5.7  28.2 ± 3.7  0.81  FS (%)  34.6 ± 4.6  36.9 ± 4.9  0.14  AOD: aortic diameter; EF: ejection fraction; LAD: left atrial dimension; IVSTd: interventricular septal thickness diameter at the end diastole; PWTd: posterior wall thickness diameter; LVDd: left ventricular internal dimension in diastole; LVDs: left ventricular diameter in end systole; FS: fractional shortening; SD: standard deviation. Table 3: Comparison of annulus areas, perimeters and their changes   AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  Systolic area (cm2)  5.6 ± 2.1  6.3 ± 1.0  0.21  Indexed systolic area (cm2/BSA)  3.7 ± 1.1  3.9 ± 0.6  0.48  Diastolic area (cm2)  4.8 ± 1.8  5.4 ± 1.1  0.22  Indexed diastolic area (cm2/BSA)  3.2 ± 1.0  3.4 ± 0.6  0.53  Δ area (cm2)  0.8 ± 0.4  0.9 ± 0.6  0.62  Systolic perimeter (mm)  86.1 ± 16.1  92.9 ± 8.3  0.14  Diastolic perimeter (mm)  79.0 ± 15.7  86.2 ± 9.4  0.12    AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  Systolic area (cm2)  5.6 ± 2.1  6.3 ± 1.0  0.21  Indexed systolic area (cm2/BSA)  3.7 ± 1.1  3.9 ± 0.6  0.48  Diastolic area (cm2)  4.8 ± 1.8  5.4 ± 1.1  0.22  Indexed diastolic area (cm2/BSA)  3.2 ± 1.0  3.4 ± 0.6  0.53  Δ area (cm2)  0.8 ± 0.4  0.9 ± 0.6  0.62  Systolic perimeter (mm)  86.1 ± 16.1  92.9 ± 8.3  0.14  Diastolic perimeter (mm)  79.0 ± 15.7  86.2 ± 9.4  0.12  AVNeo: aortic valve neocuspidization; BSA: body surface area; SD: standard deviation. Table 3: Comparison of annulus areas, perimeters and their changes   AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  Systolic area (cm2)  5.6 ± 2.1  6.3 ± 1.0  0.21  Indexed systolic area (cm2/BSA)  3.7 ± 1.1  3.9 ± 0.6  0.48  Diastolic area (cm2)  4.8 ± 1.8  5.4 ± 1.1  0.22  Indexed diastolic area (cm2/BSA)  3.2 ± 1.0  3.4 ± 0.6  0.53  Δ area (cm2)  0.8 ± 0.4  0.9 ± 0.6  0.62  Systolic perimeter (mm)  86.1 ± 16.1  92.9 ± 8.3  0.14  Diastolic perimeter (mm)  79.0 ± 15.7  86.2 ± 9.4  0.12    AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  Systolic area (cm2)  5.6 ± 2.1  6.3 ± 1.0  0.21  Indexed systolic area (cm2/BSA)  3.7 ± 1.1  3.9 ± 0.6  0.48  Diastolic area (cm2)  4.8 ± 1.8  5.4 ± 1.1  0.22  Indexed diastolic area (cm2/BSA)  3.2 ± 1.0  3.4 ± 0.6  0.53  Δ area (cm2)  0.8 ± 0.4  0.9 ± 0.6  0.62  Systolic perimeter (mm)  86.1 ± 16.1  92.9 ± 8.3  0.14  Diastolic perimeter (mm)  79.0 ± 15.7  86.2 ± 9.4  0.12  AVNeo: aortic valve neocuspidization; BSA: body surface area; SD: standard deviation. Statistical analysis Values are expressed as mean ± standard deviation for continuous variables. The independent sample t-tests were used to compare the values between 2 groups, with P-values <0.05 considered as indicating a statistically significant difference. The χ2 test was used when all expected cell frequencies were ≥5. Otherwise, the Fisher’s exact test was used. All analyses were performed using SPSS Statistics Version 24.0 (IBM Corp. Released 2016. IBM SPSS Statistics for Windows, Version 24.0. Armonk, NY, USA: IBM Corp.). RESULTS Characteristics of patients In the AVNeo group, the mean postoperative follow-up period was 35 ± 23 months. The reasons for performing AVNeo were aortic valve stenosis (AS) in 17 patients and aortic valve regurgitation (AR) in 8 patients. The postoperative mean peak pressure gradient, mean pressure gradient and effective orifice area (EOA) were 16.1 ± 7.7 mmHg, 7.8 ± 3.3 and 2.3 ± 0.8 cm2, respectively. The mean coaptation length measured in the longitudinal view on TTE was 16.8 ± 1.9 mm, and no postoperative AR occurred throughout the follow-up period. The postoperative status was good with a low pressure gradient, a wide EOA and a long coaptation to prevent recurrent AR. The characteristics of the patients are shown in Table 1. A significant difference between the 2 groups was observed only in the variable of age. For aortic valve diseases, particularly AS, the age of the patients tended to be older, underlying the possible age-related causation. There were no significant differences in the other variables. Comparison of intracardiac data obtained using transthoracic echocardiography The functional and dimensional data are indicated in Table 2. A significant difference in the interventricular septal thickness diameter at the end diastole was recognized between the AVNeo and normal aortic valve groups. There was no significant difference in the other categorical items except the interventricular septal thickness diameter at the end diastole. The aortic annulus areas with the indexes, perimeters and their differences during the systolic and diastolic phases between the AVNeo and normal aortic valve groups are summarized in Table 3. There was no significant differences in the aortic annulus area and perimeter in the systolic and diastolic phases between the AVNeo group and the normal aortic annulus group. The systolic aortic annulus diameter and area were predominantly larger than the diastolic aortic annulus diameter and area. Moreover, the annulus diameter and area were larger in the systolic phase than in the diastolic phase in both groups. DISCUSSION AVR is still the gold standard for the treatment of aortic valve diseases. However, prosthetic valves have a stent structure for suturing and fixing to the aortic annulus. This inhibits the physiological mobility of the aortic annulus, decreases the postoperative aortic valve area and increases the postoperative pressure gradient. Moreover, we have also encountered cases that led to a prosthesis–patient mismatch not only in surgical AVR patients but also in transcatheter aortic valve replacement patients [4–6]. AVNeo with glutaraldehyde-treated autologous pericardium has been performed since 2007 [7]. This procedure consists of total resection of the aortic cusps and direct suture of the glutaraldehyde-treated autologous pericardium to the aortic annulus. The features of this technique can be applied not only to AR but also to other aortic valve pathologies such AS or aortic valve infective endocarditis, and it can be applied to unicuspid [8], bicuspid [9] and quadricuspid valves [10]. Recently, we have successfully treated a patient with prosthetic valve endocarditis by AVNeo using glutaraldehyde-treated bovine pericardium [11]. AVNeo has been reported to afford good haemodynamics because direct suture of the pericardium to the aortic annulus maintains an EOA, which becomes almost equal to the area of the aortic annulus [7]. After AVR with a prosthetic valve, the movement of the aortic annulus is fixed by sutures, and the natural contraction/expansion of the aortic base is lost. As a result, the EOA will decrease, and the postoperative pressure gradient may increase. The aortic annulus changes throughout the cardiac cycle particularly after the introduction of transcatheter aortic valve replacement because precise aortic root measurement is necessary for choosing the correct size of the prosthesis valve to minimize the risk of paravalvular leakage [12–14]. A normal aortic valve annulus changes during the cardiac cycle, expanding in the systolic phase and contracting in the diastolic phase [15]. Moreover, recent studies have reported a significant change in the aortic annulus during the cardiac cycle [16, 17]. Yamamoto et al. [18] compared the aortic annulus dimensions after AVNeo with those after AVR and with those of a normal aortic valve using electrocardiography-gated multidetector computed tomography and concluded that the aortic annulus dimensions after AVNeo were similar to those of normal aortic valves. In this study, systolic or diastolic areas including index, changes during the cardiac cycle and perimeter were not significantly different between the AVNeo group and the normal aortic valve group. This indicates that as long as the neocuspidized leaflets function without any problems, the movement of the aortic annulus after AVNeo is physiologically preserved, and a wider EOA can be maintained, which makes it possible to keep the postoperative pressure gradient lower. In this study, we first measured the aortic annulus dimensions in the patients after AVNeo and in the patients with a normal aortic annulus using TTE. The advantages of TTE are its non-invasiveness, availability or portability and no requirement for contrast enhancement. The disadvantages of TTE are its operator dependence, 2-dimensional evaluation and limited image quality, which were also indicated as limitations of this study. The establishment of the Association for Aortic Valve Neo-Cuspidization was aimed at achieving the steady development and dissemination of AVNeo. Further improvements in the quality of life of patients will be pursued based on the enhancement of surgical procedures and accumulation of treatment data. Taking all these results into consideration, AVNeo is, therefore, an operation that is based more on the physiology of the aortic valve without losing the expansion and contraction abilities of the aortic annulus. CONCLUSION The aortic annulus dimensions after AVNeo were found to be similar to those of normal aortic valves. In the future, AVNeo, which can maintain postoperative physiological haemodynamics, is a technique that can potentially be adaptable to not only patients with AS but also patients with other aortic valve pathologies, and be beneficial to the patients as long as the neocuspidized leaflets function without any problems. Further randomized, multicentre prospective studies are necessary to confirm the results of this study. ACKNOWLEDGEMENTS We are indebted to Dr Edward F. Barroga (http://orcid.org/0000-0002-8920-2607) for reviewing and editing the manuscript. Conflict of interest: none declared. REFERENCES 1 Duran CM, Gometza B, Kumar N, Gallo R, Martin-Duran R. Aortic valve replacement with freehand autologous pericardium. J Thorac Cardiovasc Surg  1995; 110: 511– 6. Google Scholar CrossRef Search ADS PubMed  2 Al Halees Z, Al Shahid M, Al Sanei A, Sallehuddin A, Duran C. Up to 16 years follow-up of aortic valve reconstruction with pericardium: a stentless readily available cheap valve? Eur J Cardiothorac Surg  2005; 28: 200– 5; discussion 205. Google Scholar CrossRef Search ADS PubMed  3 Ozaki S, Kawase I, Yamashita H, Uchida S, Nozawa Y, Matsuyama T et al.   Aortic valve reconstruction using self-developed aortic valve plasty system in aortic valve disease. Interact CardioVasc Thorac Surg  2011; 12: 550– 3. Google Scholar CrossRef Search ADS PubMed  4 Mooney J, Sellers SL, Blanke P, Pibarot P, Hahn RT, Dvir D et al.   CT-defined prosthesis-patient mismatch downgrades frequency and severity, and demonstrates no association with adverse outcomes after transcatheter aortic valve replacement. JACC Cardiovasc Interv  2017; 10: 1578– 87. Google Scholar CrossRef Search ADS PubMed  5 Zorn GLIII, Little SH, Tadros P, Deeb GM, Gleason TG, Heiser J et al.   Prosthesis-patient mismatch in high-risk patients with severe aortic stenosis: a randomized trial of a self-expanding prosthesis. J Thorac Cardiovasc Surg  2016; 151: 1014– 22. 1023.e1-3. Google Scholar CrossRef Search ADS PubMed  6 Ghanta RK, Kron IL. Patient-prosthesis mismatch: surgical aortic valve replacement versus transcatheter aortic valve replacement in high risk patients with aortic stenosis. J Thorac Dis  2016; 8: E1441– 3. Google Scholar CrossRef Search ADS PubMed  7 Ozaki S, Kawase I, Yamashita H, Uchida S, Nozawa Y, Takatoh M et al.   A total of 404 cases of aortic valve reconstruction with glutaraldehyde-treated autologous pericardium. J Thorac Cardiovasc Surg  2014; 147: 301– 6. Google Scholar CrossRef Search ADS PubMed  8 Kawase I, Ozaki S, Yamashita H, Uchida S, Nozawa Y, Matsuyama T et al.   Aortic valve reconstruction of unicuspid aortic valve by tricuspidization using autologous pericardium. Ann Thorac Surg  2012; 94: 1180– 4. Google Scholar CrossRef Search ADS PubMed  9 Ozaki S, Kawase I, Yamashita H, Uchida S, Nozawa Y, Takatoh M et al.   Reconstruction of bicuspid aortic valve with autologous pericardium: usefulness of tricuspidization. Circ J  2014; 78: 1144– 51. Google Scholar CrossRef Search ADS PubMed  10 Kawase I, Ozaki S, Yamashita H, Uchida S, Nozawa Y, Matsuyama T et al.   Original aortic valve plasty with autologous pericardium for quadricuspid valve. Ann Thorac Surg  2011; 91: 1598– 9. Google Scholar CrossRef Search ADS PubMed  11 Iida Y, Shimura K, Akiyama S, Sawa S. Treatment of prosthetic valve endocarditis by aortic valve neocuspidization using bovine pericardium. Eur J Cardiothorac Surg  2017; doi: 10.1093/ejcts/ezx380. 12 O’Sullivan KE, Gough A, Segurado R, Barry M, Sugrue D, Hurley J. Is valve choice a significant determinant of paravalular leak post-transcatheter aortic valve implantation? A systematic review and meta-analysis. Eur J Cardiothorac Surg  2014; 45: 826– 33. Google Scholar CrossRef Search ADS PubMed  13 Jerez-Valero M, Urena M, Webb JG, Tamburino C, Munoz-Garcia AJ, Cheema A et al.   Clinical impact of aortic regurgitation after transcatheter aortic valve replacement: insights into the degree and acuteness of presentation. JACC Cardiovasc Interv  2014; 7: 1022– 32. Google Scholar CrossRef Search ADS PubMed  14 Chrysohoou C, Hayek SS, Spilias N, Lerakis S. Echocardiographic and clinical factors related to paravalvular leak incidence in low-gradient severe aortic stenosis patients post-transcatheter aortic valve implantation. Eur Heart J Cardiovasc Imaging  2015; 16: 558– 63. Google Scholar CrossRef Search ADS PubMed  15 Hamdan A, Guetta V, Konen E, Goitein O, Segev A, Raanani E et al.   Deformation dynamics and mechanical properties of the aortic annulus by 4-dimensional computed tomography: insights into the functional anatomy of the aortic valve complex and implications for transcatheter aortic valve therapy. J Am Coll Cardiol  2012; 59: 119– 27. Google Scholar CrossRef Search ADS PubMed  16 de Heer LM, Budde RP, van Prehn J, Mali WP, Bartels LW, Stella PR et al.   Pulsatile distention of the nondiseased and stenotic aortic valve annulus: analysis with electrocardiogram-gated computed tomography. Ann Thorac Surg  2012; 93: 516– 22. Google Scholar CrossRef Search ADS PubMed  17 de Heer LM, Budde RP, Mali WP, de Vos AM, van Herwerden LA, Kluin J. Aortic root dimension changes during systole and diastole: evaluation with ECG-gated multidetector row computed tomography. Int J Cardiovasc Imaging  2011; 27: 1195– 204. Google Scholar CrossRef Search ADS PubMed  18 Yamamoto Y, Iino K, Shintani Y, Kato H, Kimura K, Watanabe G et al.   Comparison of aortic annulus dimension after aortic valve neocuspidization with valve replacement and normal valve. Semin Thorac Cardiovasc Surg  2017; 29: 143– 9. Google Scholar CrossRef Search ADS 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 European Journal of Cardio-Thoracic Surgery Oxford University Press

Comparison of aortic annulus dimensions after aortic valve neocuspidization with those of normal aortic valve using transthoracic echocardiography

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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.
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Abstract

Abstract OBJECTIVES This study aimed to elucidate the physiological feasibility of aortic valve neocuspidization (AVNeo) by comparing the aortic annulus dimensions between patients after AVNeo and patients with normal aortic valves. METHODS From December 2010 to October 2017, we performed AVNeo for various aortic valve pathologies in 147 patients. Of these patients, the aortic annulus dimensions were measured in 25 patients who underwent AVNeo for aortic valve disease as follow-up examination and compared with those measured in 15 patients who had normal aortic valves. Measurements were recorded using electrocardiography-gated transthoracic echocardiography. RESULTS No significant differences in the aortic annulus dimensions were observed between the patients who had undergone AVNeo and those who had normal aortic valves. In a cardiac cycle, the annulus area in the systolic phase was consistently larger than that in the diastolic phase, which was a physiological condition. CONCLUSIONS The movement of the aortic annulus after AVNeo is comparable with that of the aortic annulus of a normal aortic valve. Thus, AVNeo can be regarded as a more physiological operation in that it maintains the characteristics of the aortic valve similar to those of a normal aortic valve. Aortic valve neocuspidization, Aortic annulus dimension, Transthoracic echocardiography INTRODUCTION Aortic valve reconstruction with glutaraldehyde-treated autologous pericardium for patients with aortic valve disease was started by Duran et al. [1] in 1988. Since then, the long-term results after a 16-year follow-up were reported [2]. Subsequently, Ozaki et al. [3] developed aortic valve reconstruction with an autologous pericardium which be came known as aortic valve neocuspidization (AVNeo). To date, the standard operation for aortic valve disease has been aortic valve replacement (AVR) using a prosthetic valve. Both mechanical and bioprosthetic valves have a stent structure for suturing and fixing to the aortic valve annulus, which in turn inhibits the aortic annulus movement, decreases the postoperative aortic valve area, increases the pressure gradient and occasionally increases the prosthesis–patient mismatch. We have performed AVNeo for various aortic valve diseases since 2010. In this study, we elucidated whether AVNeo is physiologically acceptable by evaluating the aortic annulus movement in a cardiac cycle using transthoracic echocardiography (TTE). METHODS Characteristics of patients and study design From December 2010 to October 2017, we performed AVNeo for various aortic valve pathologies. For the AVNeo group, we retrospectively evaluated and reviewed 25 random patients (11 men and 14 women) who underwent AVNeo. Their mean age was 73.9 ± 14.4 (44–92) years. For the normal aortic valve group, 8 men and 7 women were included, and their mean age was 60.7 ± 24.5 (16–89) years. The characteristics of the patients are shown in Table 1. In the normal aortic valve group, the reasons for using TTE were as follows: preoperative evaluation for gastroenteric surgery (7), signs of arrhythmia (6) and leg oedema (2). Table 1: Characteristics of patients   AVNeo (n = 25)  Normal (n = 15)  P-value  AS, n (%)  17 (68)  0 (0)  NA  AR, n (%)  8 (32)  0 (0)  NA  Age (years), mean ± SD  73.9 ± 18.8  60.7 ± 24.5  0.038  Male gender, n (%)  11 (44)  8 (53)  0.57  BSA (m2), mean ± SD  1.5 ± 0.2  1.6 ± 0.2  0.073  Hypertension, n (%)  18 (72)  11 (73)  0.92  Diabetes, n (%)  5 (20)  3 (20)  0.74  Dyslipidaemia, n (%)  14 (56)  7 (47)  0.57  Chronic kidney disease, n (%)  12 (48)  3 (20)  0.077  Ischaemic heart disease, n (%)  4 (16)  4 (27)  0.41  Cerebral infarction, n (%)  2 (8)  1 (7)  0.88    AVNeo (n = 25)  Normal (n = 15)  P-value  AS, n (%)  17 (68)  0 (0)  NA  AR, n (%)  8 (32)  0 (0)  NA  Age (years), mean ± SD  73.9 ± 18.8  60.7 ± 24.5  0.038  Male gender, n (%)  11 (44)  8 (53)  0.57  BSA (m2), mean ± SD  1.5 ± 0.2  1.6 ± 0.2  0.073  Hypertension, n (%)  18 (72)  11 (73)  0.92  Diabetes, n (%)  5 (20)  3 (20)  0.74  Dyslipidaemia, n (%)  14 (56)  7 (47)  0.57  Chronic kidney disease, n (%)  12 (48)  3 (20)  0.077  Ischaemic heart disease, n (%)  4 (16)  4 (27)  0.41  Cerebral infarction, n (%)  2 (8)  1 (7)  0.88  AR: aortic valve regurgitation; AS: aortic valve stenosis; BSA: body surface area; NA: not applicable; SD: standard deviation. Table 1: Characteristics of patients   AVNeo (n = 25)  Normal (n = 15)  P-value  AS, n (%)  17 (68)  0 (0)  NA  AR, n (%)  8 (32)  0 (0)  NA  Age (years), mean ± SD  73.9 ± 18.8  60.7 ± 24.5  0.038  Male gender, n (%)  11 (44)  8 (53)  0.57  BSA (m2), mean ± SD  1.5 ± 0.2  1.6 ± 0.2  0.073  Hypertension, n (%)  18 (72)  11 (73)  0.92  Diabetes, n (%)  5 (20)  3 (20)  0.74  Dyslipidaemia, n (%)  14 (56)  7 (47)  0.57  Chronic kidney disease, n (%)  12 (48)  3 (20)  0.077  Ischaemic heart disease, n (%)  4 (16)  4 (27)  0.41  Cerebral infarction, n (%)  2 (8)  1 (7)  0.88    AVNeo (n = 25)  Normal (n = 15)  P-value  AS, n (%)  17 (68)  0 (0)  NA  AR, n (%)  8 (32)  0 (0)  NA  Age (years), mean ± SD  73.9 ± 18.8  60.7 ± 24.5  0.038  Male gender, n (%)  11 (44)  8 (53)  0.57  BSA (m2), mean ± SD  1.5 ± 0.2  1.6 ± 0.2  0.073  Hypertension, n (%)  18 (72)  11 (73)  0.92  Diabetes, n (%)  5 (20)  3 (20)  0.74  Dyslipidaemia, n (%)  14 (56)  7 (47)  0.57  Chronic kidney disease, n (%)  12 (48)  3 (20)  0.077  Ischaemic heart disease, n (%)  4 (16)  4 (27)  0.41  Cerebral infarction, n (%)  2 (8)  1 (7)  0.88  AR: aortic valve regurgitation; AS: aortic valve stenosis; BSA: body surface area; NA: not applicable; SD: standard deviation. Transthoracic echocardiography examination Electrocardiography-gated TTE was performed using the ultrasound units SSA-790A (AplioXG™) and TUS-400 (Aplio400) (both from Toshiba Medical Systems Co., Otawara, Japan). In the AVNeo group, the patients underwent TTE as a routine follow-up after AVNeo. In the normal aortic valve group, 15 patients with no aortic valve disease were selected randomly during the study period. Measurements of the aortic annulus and its perimeter during the cardiac cycle were performed by skilled echocardiographers using electrocardiography. Other echocardiographic data such as ejection fraction and left atrial diameter were also obtained. The differences between the 2 groups are shown in Table 2. The annulus areas, perimeters and their changes are listed in Table 3. When comparing the areas and perimeters of the aortic annulus to minimize the effects of physique, the aortic annulus area was divided by body surface area. Table 2: Comparison of transthoracic echocardiogram data between the AVNeo group and the normal valve group   AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  EF (%)  64.6 ± 5.5  65.7 ± 5.8  0.54  AOD (mm)  26.7 ± 5.6  25.3 ± 3.3  0.38  LAD (mm)  37.2 ± 5.5  35.4 ± 3.5  0.27  IVSTd (mm)  11.0 ± 1.4  9.7 ± 1.3  0.006  PWTd (mm)  10.6 ± 1.2  9.8 ± 1.3  0.056  LVDd (mm)  41.6 ± 9.0  44.7 ± 4.9  0.22  LVDs (mm)  28.6 ± 5.7  28.2 ± 3.7  0.81  FS (%)  34.6 ± 4.6  36.9 ± 4.9  0.14    AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  EF (%)  64.6 ± 5.5  65.7 ± 5.8  0.54  AOD (mm)  26.7 ± 5.6  25.3 ± 3.3  0.38  LAD (mm)  37.2 ± 5.5  35.4 ± 3.5  0.27  IVSTd (mm)  11.0 ± 1.4  9.7 ± 1.3  0.006  PWTd (mm)  10.6 ± 1.2  9.8 ± 1.3  0.056  LVDd (mm)  41.6 ± 9.0  44.7 ± 4.9  0.22  LVDs (mm)  28.6 ± 5.7  28.2 ± 3.7  0.81  FS (%)  34.6 ± 4.6  36.9 ± 4.9  0.14  AOD: aortic diameter; EF: ejection fraction; LAD: left atrial dimension; IVSTd: interventricular septal thickness diameter at the end diastole; PWTd: posterior wall thickness diameter; LVDd: left ventricular internal dimension in diastole; LVDs: left ventricular diameter in end systole; FS: fractional shortening; SD: standard deviation. Table 2: Comparison of transthoracic echocardiogram data between the AVNeo group and the normal valve group   AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  EF (%)  64.6 ± 5.5  65.7 ± 5.8  0.54  AOD (mm)  26.7 ± 5.6  25.3 ± 3.3  0.38  LAD (mm)  37.2 ± 5.5  35.4 ± 3.5  0.27  IVSTd (mm)  11.0 ± 1.4  9.7 ± 1.3  0.006  PWTd (mm)  10.6 ± 1.2  9.8 ± 1.3  0.056  LVDd (mm)  41.6 ± 9.0  44.7 ± 4.9  0.22  LVDs (mm)  28.6 ± 5.7  28.2 ± 3.7  0.81  FS (%)  34.6 ± 4.6  36.9 ± 4.9  0.14    AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  EF (%)  64.6 ± 5.5  65.7 ± 5.8  0.54  AOD (mm)  26.7 ± 5.6  25.3 ± 3.3  0.38  LAD (mm)  37.2 ± 5.5  35.4 ± 3.5  0.27  IVSTd (mm)  11.0 ± 1.4  9.7 ± 1.3  0.006  PWTd (mm)  10.6 ± 1.2  9.8 ± 1.3  0.056  LVDd (mm)  41.6 ± 9.0  44.7 ± 4.9  0.22  LVDs (mm)  28.6 ± 5.7  28.2 ± 3.7  0.81  FS (%)  34.6 ± 4.6  36.9 ± 4.9  0.14  AOD: aortic diameter; EF: ejection fraction; LAD: left atrial dimension; IVSTd: interventricular septal thickness diameter at the end diastole; PWTd: posterior wall thickness diameter; LVDd: left ventricular internal dimension in diastole; LVDs: left ventricular diameter in end systole; FS: fractional shortening; SD: standard deviation. Table 3: Comparison of annulus areas, perimeters and their changes   AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  Systolic area (cm2)  5.6 ± 2.1  6.3 ± 1.0  0.21  Indexed systolic area (cm2/BSA)  3.7 ± 1.1  3.9 ± 0.6  0.48  Diastolic area (cm2)  4.8 ± 1.8  5.4 ± 1.1  0.22  Indexed diastolic area (cm2/BSA)  3.2 ± 1.0  3.4 ± 0.6  0.53  Δ area (cm2)  0.8 ± 0.4  0.9 ± 0.6  0.62  Systolic perimeter (mm)  86.1 ± 16.1  92.9 ± 8.3  0.14  Diastolic perimeter (mm)  79.0 ± 15.7  86.2 ± 9.4  0.12    AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  Systolic area (cm2)  5.6 ± 2.1  6.3 ± 1.0  0.21  Indexed systolic area (cm2/BSA)  3.7 ± 1.1  3.9 ± 0.6  0.48  Diastolic area (cm2)  4.8 ± 1.8  5.4 ± 1.1  0.22  Indexed diastolic area (cm2/BSA)  3.2 ± 1.0  3.4 ± 0.6  0.53  Δ area (cm2)  0.8 ± 0.4  0.9 ± 0.6  0.62  Systolic perimeter (mm)  86.1 ± 16.1  92.9 ± 8.3  0.14  Diastolic perimeter (mm)  79.0 ± 15.7  86.2 ± 9.4  0.12  AVNeo: aortic valve neocuspidization; BSA: body surface area; SD: standard deviation. Table 3: Comparison of annulus areas, perimeters and their changes   AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  Systolic area (cm2)  5.6 ± 2.1  6.3 ± 1.0  0.21  Indexed systolic area (cm2/BSA)  3.7 ± 1.1  3.9 ± 0.6  0.48  Diastolic area (cm2)  4.8 ± 1.8  5.4 ± 1.1  0.22  Indexed diastolic area (cm2/BSA)  3.2 ± 1.0  3.4 ± 0.6  0.53  Δ area (cm2)  0.8 ± 0.4  0.9 ± 0.6  0.62  Systolic perimeter (mm)  86.1 ± 16.1  92.9 ± 8.3  0.14  Diastolic perimeter (mm)  79.0 ± 15.7  86.2 ± 9.4  0.12    AVNeo (n = 25), mean ± SD  Normal (n = 15), mean ± SD  P-value  Systolic area (cm2)  5.6 ± 2.1  6.3 ± 1.0  0.21  Indexed systolic area (cm2/BSA)  3.7 ± 1.1  3.9 ± 0.6  0.48  Diastolic area (cm2)  4.8 ± 1.8  5.4 ± 1.1  0.22  Indexed diastolic area (cm2/BSA)  3.2 ± 1.0  3.4 ± 0.6  0.53  Δ area (cm2)  0.8 ± 0.4  0.9 ± 0.6  0.62  Systolic perimeter (mm)  86.1 ± 16.1  92.9 ± 8.3  0.14  Diastolic perimeter (mm)  79.0 ± 15.7  86.2 ± 9.4  0.12  AVNeo: aortic valve neocuspidization; BSA: body surface area; SD: standard deviation. Statistical analysis Values are expressed as mean ± standard deviation for continuous variables. The independent sample t-tests were used to compare the values between 2 groups, with P-values <0.05 considered as indicating a statistically significant difference. The χ2 test was used when all expected cell frequencies were ≥5. Otherwise, the Fisher’s exact test was used. All analyses were performed using SPSS Statistics Version 24.0 (IBM Corp. Released 2016. IBM SPSS Statistics for Windows, Version 24.0. Armonk, NY, USA: IBM Corp.). RESULTS Characteristics of patients In the AVNeo group, the mean postoperative follow-up period was 35 ± 23 months. The reasons for performing AVNeo were aortic valve stenosis (AS) in 17 patients and aortic valve regurgitation (AR) in 8 patients. The postoperative mean peak pressure gradient, mean pressure gradient and effective orifice area (EOA) were 16.1 ± 7.7 mmHg, 7.8 ± 3.3 and 2.3 ± 0.8 cm2, respectively. The mean coaptation length measured in the longitudinal view on TTE was 16.8 ± 1.9 mm, and no postoperative AR occurred throughout the follow-up period. The postoperative status was good with a low pressure gradient, a wide EOA and a long coaptation to prevent recurrent AR. The characteristics of the patients are shown in Table 1. A significant difference between the 2 groups was observed only in the variable of age. For aortic valve diseases, particularly AS, the age of the patients tended to be older, underlying the possible age-related causation. There were no significant differences in the other variables. Comparison of intracardiac data obtained using transthoracic echocardiography The functional and dimensional data are indicated in Table 2. A significant difference in the interventricular septal thickness diameter at the end diastole was recognized between the AVNeo and normal aortic valve groups. There was no significant difference in the other categorical items except the interventricular septal thickness diameter at the end diastole. The aortic annulus areas with the indexes, perimeters and their differences during the systolic and diastolic phases between the AVNeo and normal aortic valve groups are summarized in Table 3. There was no significant differences in the aortic annulus area and perimeter in the systolic and diastolic phases between the AVNeo group and the normal aortic annulus group. The systolic aortic annulus diameter and area were predominantly larger than the diastolic aortic annulus diameter and area. Moreover, the annulus diameter and area were larger in the systolic phase than in the diastolic phase in both groups. DISCUSSION AVR is still the gold standard for the treatment of aortic valve diseases. However, prosthetic valves have a stent structure for suturing and fixing to the aortic annulus. This inhibits the physiological mobility of the aortic annulus, decreases the postoperative aortic valve area and increases the postoperative pressure gradient. Moreover, we have also encountered cases that led to a prosthesis–patient mismatch not only in surgical AVR patients but also in transcatheter aortic valve replacement patients [4–6]. AVNeo with glutaraldehyde-treated autologous pericardium has been performed since 2007 [7]. This procedure consists of total resection of the aortic cusps and direct suture of the glutaraldehyde-treated autologous pericardium to the aortic annulus. The features of this technique can be applied not only to AR but also to other aortic valve pathologies such AS or aortic valve infective endocarditis, and it can be applied to unicuspid [8], bicuspid [9] and quadricuspid valves [10]. Recently, we have successfully treated a patient with prosthetic valve endocarditis by AVNeo using glutaraldehyde-treated bovine pericardium [11]. AVNeo has been reported to afford good haemodynamics because direct suture of the pericardium to the aortic annulus maintains an EOA, which becomes almost equal to the area of the aortic annulus [7]. After AVR with a prosthetic valve, the movement of the aortic annulus is fixed by sutures, and the natural contraction/expansion of the aortic base is lost. As a result, the EOA will decrease, and the postoperative pressure gradient may increase. The aortic annulus changes throughout the cardiac cycle particularly after the introduction of transcatheter aortic valve replacement because precise aortic root measurement is necessary for choosing the correct size of the prosthesis valve to minimize the risk of paravalvular leakage [12–14]. A normal aortic valve annulus changes during the cardiac cycle, expanding in the systolic phase and contracting in the diastolic phase [15]. Moreover, recent studies have reported a significant change in the aortic annulus during the cardiac cycle [16, 17]. Yamamoto et al. [18] compared the aortic annulus dimensions after AVNeo with those after AVR and with those of a normal aortic valve using electrocardiography-gated multidetector computed tomography and concluded that the aortic annulus dimensions after AVNeo were similar to those of normal aortic valves. In this study, systolic or diastolic areas including index, changes during the cardiac cycle and perimeter were not significantly different between the AVNeo group and the normal aortic valve group. This indicates that as long as the neocuspidized leaflets function without any problems, the movement of the aortic annulus after AVNeo is physiologically preserved, and a wider EOA can be maintained, which makes it possible to keep the postoperative pressure gradient lower. In this study, we first measured the aortic annulus dimensions in the patients after AVNeo and in the patients with a normal aortic annulus using TTE. The advantages of TTE are its non-invasiveness, availability or portability and no requirement for contrast enhancement. The disadvantages of TTE are its operator dependence, 2-dimensional evaluation and limited image quality, which were also indicated as limitations of this study. The establishment of the Association for Aortic Valve Neo-Cuspidization was aimed at achieving the steady development and dissemination of AVNeo. Further improvements in the quality of life of patients will be pursued based on the enhancement of surgical procedures and accumulation of treatment data. Taking all these results into consideration, AVNeo is, therefore, an operation that is based more on the physiology of the aortic valve without losing the expansion and contraction abilities of the aortic annulus. CONCLUSION The aortic annulus dimensions after AVNeo were found to be similar to those of normal aortic valves. In the future, AVNeo, which can maintain postoperative physiological haemodynamics, is a technique that can potentially be adaptable to not only patients with AS but also patients with other aortic valve pathologies, and be beneficial to the patients as long as the neocuspidized leaflets function without any problems. Further randomized, multicentre prospective studies are necessary to confirm the results of this study. ACKNOWLEDGEMENTS We are indebted to Dr Edward F. Barroga (http://orcid.org/0000-0002-8920-2607) for reviewing and editing the manuscript. Conflict of interest: none declared. REFERENCES 1 Duran CM, Gometza B, Kumar N, Gallo R, Martin-Duran R. Aortic valve replacement with freehand autologous pericardium. J Thorac Cardiovasc Surg  1995; 110: 511– 6. Google Scholar CrossRef Search ADS PubMed  2 Al Halees Z, Al Shahid M, Al Sanei A, Sallehuddin A, Duran C. Up to 16 years follow-up of aortic valve reconstruction with pericardium: a stentless readily available cheap valve? Eur J Cardiothorac Surg  2005; 28: 200– 5; discussion 205. Google Scholar CrossRef Search ADS PubMed  3 Ozaki S, Kawase I, Yamashita H, Uchida S, Nozawa Y, Matsuyama T et al.   Aortic valve reconstruction using self-developed aortic valve plasty system in aortic valve disease. Interact CardioVasc Thorac Surg  2011; 12: 550– 3. Google Scholar CrossRef Search ADS PubMed  4 Mooney J, Sellers SL, Blanke P, Pibarot P, Hahn RT, Dvir D et al.   CT-defined prosthesis-patient mismatch downgrades frequency and severity, and demonstrates no association with adverse outcomes after transcatheter aortic valve replacement. JACC Cardiovasc Interv  2017; 10: 1578– 87. Google Scholar CrossRef Search ADS PubMed  5 Zorn GLIII, Little SH, Tadros P, Deeb GM, Gleason TG, Heiser J et al.   Prosthesis-patient mismatch in high-risk patients with severe aortic stenosis: a randomized trial of a self-expanding prosthesis. J Thorac Cardiovasc Surg  2016; 151: 1014– 22. 1023.e1-3. Google Scholar CrossRef Search ADS PubMed  6 Ghanta RK, Kron IL. Patient-prosthesis mismatch: surgical aortic valve replacement versus transcatheter aortic valve replacement in high risk patients with aortic stenosis. J Thorac Dis  2016; 8: E1441– 3. Google Scholar CrossRef Search ADS PubMed  7 Ozaki S, Kawase I, Yamashita H, Uchida S, Nozawa Y, Takatoh M et al.   A total of 404 cases of aortic valve reconstruction with glutaraldehyde-treated autologous pericardium. J Thorac Cardiovasc Surg  2014; 147: 301– 6. Google Scholar CrossRef Search ADS PubMed  8 Kawase I, Ozaki S, Yamashita H, Uchida S, Nozawa Y, Matsuyama T et al.   Aortic valve reconstruction of unicuspid aortic valve by tricuspidization using autologous pericardium. Ann Thorac Surg  2012; 94: 1180– 4. Google Scholar CrossRef Search ADS PubMed  9 Ozaki S, Kawase I, Yamashita H, Uchida S, Nozawa Y, Takatoh M et al.   Reconstruction of bicuspid aortic valve with autologous pericardium: usefulness of tricuspidization. Circ J  2014; 78: 1144– 51. Google Scholar CrossRef Search ADS PubMed  10 Kawase I, Ozaki S, Yamashita H, Uchida S, Nozawa Y, Matsuyama T et al.   Original aortic valve plasty with autologous pericardium for quadricuspid valve. Ann Thorac Surg  2011; 91: 1598– 9. Google Scholar CrossRef Search ADS PubMed  11 Iida Y, Shimura K, Akiyama S, Sawa S. Treatment of prosthetic valve endocarditis by aortic valve neocuspidization using bovine pericardium. Eur J Cardiothorac Surg  2017; doi: 10.1093/ejcts/ezx380. 12 O’Sullivan KE, Gough A, Segurado R, Barry M, Sugrue D, Hurley J. Is valve choice a significant determinant of paravalular leak post-transcatheter aortic valve implantation? A systematic review and meta-analysis. Eur J Cardiothorac Surg  2014; 45: 826– 33. Google Scholar CrossRef Search ADS PubMed  13 Jerez-Valero M, Urena M, Webb JG, Tamburino C, Munoz-Garcia AJ, Cheema A et al.   Clinical impact of aortic regurgitation after transcatheter aortic valve replacement: insights into the degree and acuteness of presentation. JACC Cardiovasc Interv  2014; 7: 1022– 32. Google Scholar CrossRef Search ADS PubMed  14 Chrysohoou C, Hayek SS, Spilias N, Lerakis S. Echocardiographic and clinical factors related to paravalvular leak incidence in low-gradient severe aortic stenosis patients post-transcatheter aortic valve implantation. Eur Heart J Cardiovasc Imaging  2015; 16: 558– 63. Google Scholar CrossRef Search ADS PubMed  15 Hamdan A, Guetta V, Konen E, Goitein O, Segev A, Raanani E et al.   Deformation dynamics and mechanical properties of the aortic annulus by 4-dimensional computed tomography: insights into the functional anatomy of the aortic valve complex and implications for transcatheter aortic valve therapy. J Am Coll Cardiol  2012; 59: 119– 27. Google Scholar CrossRef Search ADS PubMed  16 de Heer LM, Budde RP, van Prehn J, Mali WP, Bartels LW, Stella PR et al.   Pulsatile distention of the nondiseased and stenotic aortic valve annulus: analysis with electrocardiogram-gated computed tomography. Ann Thorac Surg  2012; 93: 516– 22. Google Scholar CrossRef Search ADS PubMed  17 de Heer LM, Budde RP, Mali WP, de Vos AM, van Herwerden LA, Kluin J. Aortic root dimension changes during systole and diastole: evaluation with ECG-gated multidetector row computed tomography. Int J Cardiovasc Imaging  2011; 27: 1195– 204. Google Scholar CrossRef Search ADS PubMed  18 Yamamoto Y, Iino K, Shintani Y, Kato H, Kimura K, Watanabe G et al.   Comparison of aortic annulus dimension after aortic valve neocuspidization with valve replacement and normal valve. Semin Thorac Cardiovasc Surg  2017; 29: 143– 9. Google Scholar CrossRef Search ADS 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)

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European Journal of Cardio-Thoracic SurgeryOxford University Press

Published: May 3, 2018

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