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Sutureless Versus Stented Valve in Aortic Valve Replacement in Patients With Small Annulus
Sutureless Versus Stented Valve in Aortic Valve Replacement in Patients With Small Annulus Amjad Shalabi, MD,* Dan Spiegelstein, MD,* Leonid Sternik, MD, Micha S. Feinberg, MD, Alexander Kogan, MD, Shany Levin, MA, Boris Orlov, MD, Eyal Nachum, MD, Alexander Lipey, MD, and Ehud Raanani, MD Departments of Cardiac Surgery and Cardiology, Chaim Sheba Medical Center, Tel-Hashomer, Israel
Background. Aortic valve replacement, particularly in elderly patients with small aortic annulus, could lead to patient–prosthesis mismatch. Sutureless bioprosthesis could be an ideal solution for these patients. We compared results of aortic valve replacement with sutureless versus stented bioprosthetic valves. Methods. Of the 63 patients undergoing aortic valve replacement with sutureless bioprosthesis between 2011 and 2014 in our department, 22 (20 women, 77 ± 6 years) had a small annulus less than 21 mm (sutureless group). They were matched for sex, age, body surface area, and left ventricular ejection fraction with 22 patients (20 women, 79 ± 6 years) undergoing stented bioprosthesis valve replacement (stented group). Body mass index and body surface area were 28 ± 5 kg/m2 and 28 ± 3 kg/m2 (p [ 0.9), 1.6 ± 0.2 m2 and 1.6 ± 0.1 m2 (p [ 0.9), in the sutureless and stented groups, respectively. Logistic EuroSCOREs were similar between groups. Results. Postoperative peak transvalvular gradient was lower in the sutureless group (15 ± 7 mm Hg versus 20 ± 11 mm Hg; p [ 0.02). The indexed effective
orifice area was greater in the sutureless group (1.12 ± 0.2 cm2/m2 versus 0.82 ± 0.1 cm2/m2; p < 0.05). Aortic cross-clamp and cardiopulmonary bypass times were 47 ± 21 and 67 ± 15 minutes, respectively (p < 0.05) in the sutureless group versus 70 ± 22 and 85 ± 21 minutes, respectively (p [ 0.02) in the stented group. Intensive care unit stay, hospitalization, and major complications were not significantly different between groups. At follow-up, regression of left ventricular hypertrophy was better in the sutureless group (93 ± 21 g/m2 versus 106 ± 14 g/m2; p [ 0.02). Conclusions. Sutureless bioprosthetic valves demonstrate improved hemodynamic performance compared with stented valves in elderly patients with small aortic annulus, providing better regression of left ventricular hypertrophy and decreased rates of patient–prosthesis mismatch. Aortic cross-clamp and cardiopulmonary bypass times are also decreased.
S
of a stentless valve is technically more complicated than that of a stented valve. It requires longer cardiopulmonary bypass (CPB) and cross-clamp times. Furthermore, increased in-hospital mortality has been reported with stentless compared with stented valves [4]. Aortic root enlargement increases the annulus size in patients with a small annulus, improves hemodynamic performance, and reduces PPM. However, aortic root enlargement also increases aortic cross-clamp time, which in inexperienced hands could increase morbidity and mortality [5]. Sutureless valves have no sewing ring, which not only offers a larger EOA for any given size but also provides hemodynamic advantages like stentless prosthesis without increased difficulty during surgical implantation. Therefore, the use of a sutureless prosthesis may provide a relatively easy and safe solution for patients with a small aortic annulus. The aim of this study was to compare the hemodynamic performance and incidence of PPM in elderly patients with a small aortic root (<21 mm) undergoing either sutureless AVR with a Perceval S small aortic valve (Sorin Biomedica, Cardio, Saluggia, Italy) or conventional sutured bioprosthesis AVR.
urgical aortic valve replacement (AVR) is a definitive and proven therapy for patients with symptomatic severe aortic stenosis. Most stented prosthetic aortic valves offer an effective orifice area (EOA) less than that of the native valve because of the area reduced by the structural components of the new valve. Therefore, patients with a small aortic annulus are particularly threatened by the appearance of a patient–prosthesis mismatch (PPM), in which the EOA of a normally functioning heart valve prosthesis is too small in relation to the patient’s body size. This condition has clinical and hemodynamic implications, such as freedom from heart failure, left ventricular mass regression, and late survival [1–3]. To avoid PPM, patients with a small aortic annulus could undergo implantation of a stentless bioprosthesis and aortic root enlargement. However, the implantation
Accepted for publication Jan 4, 2016. *Drs Shalabi and Spiegelstein contributed equally to this work. Address correspondence to Dr Raanani, Department of Cardiac Surgery, Chaim Sheba Medical Center, Tel-Hashomer, 52621, Israel; email: ehud. [email protected].
Ó 2016 by The Society of Thoracic Surgeons Published by Elsevier
(Ann Thorac Surg 2016;-:-–-) Ó 2016 by The Society of Thoracic Surgeons
0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2016.01.003
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SHALABI ET AL SUTURELESS VALVES IN SMALL AORTIC ANNULUS
Material and Methods Patient Population Between December 2011 and October 2014, 63 patients underwent sutureless AVR at our medical center. We identified 22 patients with severe symptomatic aortic stenosis and small aortic annulus less than 21 mm, who underwent isolated sutureless AVR (SU group). These patients were matched for sex, age, body surface area, and left ventricular ejection fraction with 22 other patients with a small aortic annulus (selected from a group of 147 patients who underwent isolated AVR with sutured bioprosthesis size 19 to 21 mm). This second group of 22 patients underwent isolated stented sutured AVR (S group). Preoperative, operative, and postoperative data were prospectively collected at our departmental database unit. All patients were followed up in the outpatient center clinically and echocardiographically. A telephone interview was required for those lost to ambulatory follow-up. Clinical follow-up was 14 11 months in the SU group and 45 22 months in the S group (p < 0.01). Because the clinical follow-up in the S group was significantly longer, we compared only midterm echocardiographic follow-up: 9 2 months in the SU group and 8 4 months in the S group (p ¼ 0.32).
Surgical Procedures All patients from the S group underwent surgery through a median sternotomy. In the SU group, surgery was performed either by means of a full sternotomy or a mini– right thoracotomy. Standard CPB was established by cannulation of the ascending aorta and the right atrium in the sternotomy patients, whereas femoral cannulation was performed in the mini–right thoracotomy approach. Myocardial protection was achieved by using antegrade cold blood cardioplegia. Owing to the high profile of the prosthesis, sutureless AVR was performed through the high transverse aortotomy approximately 1 to 2 cm above the sinotubular junction. The valve was excised, and the annulus was decalcified in both surgical groups. Patients were monitored intraoperatively with transesophageal echocardiography for the management of CPB and prosthesis evaluation. Implantation techniques and details regarding the Perceval S valves have been previously described [6]. All stented prostheses were implanted in the supraannular position with noneverting interrupted mattress sutures.
Definition of Patient–Prosthesis Mismatch Patient–prosthesis mismatch was calculated by the echocardiographically determined EOA indexed for the body surface area. Severe PPM was defined as an indexed EOA of less than 0.65 cm2/m2, and moderate PPM was defined as an indexed EOA between 0.65 and 0.85 cm2/m2 [7].
Statistical Analysis All statistical analyses were performed with SPSS software (version 21; IBM Corp, Armonk, NY). Values are expressed as mean standard deviation or as a percentage. Continuous variables were compared by the
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Wilcoxon test, and categorical variables were compared using the McNamara test. A probability value of less than 0.05 was considered significant.
Results Patient Characteristics and Preoperative Echocardiographic Data Of the 22 patients in each group, the majority (90%) were female. Mean age was 77 6 years and 79 6 years in the SU group and S group, respectively (p ¼ 0.1). Logistic EuroSCORE I was 15 16 and 14 16 in the SU group and S group, respectively (p ¼ 0.6). Patient characteristics and preoperative echocardiographic data for both patient groups are listed in Table 1.
Operative Data Relevant operative data are summarized in Table 2. The majority of patients in the S group received Sorin Table 1. Patients and Preoperative Echocardiographic Data
Variable Age (y) Body mass index (kg/m2) Body surface area (cm2/m2) COPD (n, %) Chronic renal failure (n, %) Diabetes mellitus (n, %) Female Hypertension (n, %) Logistic EuroSCORE (%) NYHA functional class III/IV (n, %) Peripheral vascular disease (n, %) 2 (9%) Prior cerebrovascular accident (n, %) Pulmonary hypertension > 60 mm Hg (n, %) Preoperative echocardiographic data LV ejection fraction AV mean gradient (mm Hg) AV peak gradient (mm Hg) Aortic valve area (cm2) Annulus size (mm) Indexed EOA (cm2/m2) Interventricular septum (mm) LVMI (g/m2)
SU-AVR (n ¼ 22) n (%)
S-AVR (n ¼ 22) n (%)
p Value
77 6 28 5 1.6 0.2 1 (4.5%) 2 (9%)
79 6 28 3 1.6 0.1 2 (9%) 2 (9%)
0.1 0.90 0.9 0.9 1
7 (32%)
8 (36%)
0.9
20 (0.9%) 19 (86%) 15 16 12 (54%)
20 (90%) 18 (82%) 14 16 12 (55%)
1 0.9 0.6 1
0
0.6
4 (18%)
2 (9%)
0.7
1 (5%)
1 (5%)
1
0.59 0.10 0.56 0.09 47 19 47 12 76 0.66 19 0.41 14 112
30 78 20 0.1 0.67 0.1 0.8 18.6 1.4 03 0.42 0.2 2.5 15 1.7 17 115 22
0.11 0.6 0.8 0.9 0.25 0.9 0.12 0.6
AV ¼ aortic valve; AVR ¼ aortic valve replacement; COPD ¼ chronic obstructive pulmonary disease; EOA ¼ effective orifice area; EuroSCORE ¼ European System for Cardiac Operative Risk Evaluation; LV ¼ left ventricle; LVMI ¼ left ventricular mass index; NYHA ¼ New York Heart Association; S ¼ stented; SU ¼ sutureless.
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SHALABI ET AL SUTURELESS VALVES IN SMALL AORTIC ANNULUS
Table 2. Operative Data and Early Results
Variable
SU-AVR (n ¼ 22) n (%)
S-AVR (n ¼ 22) n (%)
Cross-clamp time (min) 47 21 67 15 Cardiopulmonary 70 22 85 21 bypass (min) Repositioning (n, %) 1 (5%) NA Right minimal 5 (22%) 0 thoracotomy (n, %) Early results Mortality 0 0 Transient ischemic 2 (9%) 2 (9%) attack (n, %) Permanent pacemaker (n, %) 1 (4.5%) 0 Sternal wound 1 (4.5%) 1 (4.5%) infection (n, %) Atrial fibrillation (n, %) 1 (4.5%) 4 (18%) Gastrointestinal 1 (4.5%) 1 (4.5%) bleeding (n,%) Post pericardioectomy 2 (9%) 0 syndrome (n, %) Intensive care unit (hours) 45 (24–63) 40 (18–107) Hospitalization time (days) 6.5 (5–9) 7 (6–10)
p Value 0.0008 0.02 NA 0.06
3
In the SU group, 2 patients underwent thoracocentesis for a pleural effusion after a minithoracotomy. One patient in the SU group underwent permanent pacemaker implantation because of complete atrioventricular block. Four patients in the S group compared with 1 in the SU group had postoperative atrial fibrillation. They were treated with amiodarone and returned to sinus rhythm. Intensive care unit and hospitalization times were similar in both groups.
Midterm Echocardiographic Follow-Up 1 1 0.9 1 0.37 1 0.85 0.75 1
NA ¼ not available; S-AVR ¼ stented aortic valve replacement; SU-AVR ¼ sutureless aortic valve replacement.
Mitroflow (n ¼ 14), and the remainder received Carpentier Edwards Magna Ease (n ¼ 4), Carpentier Edwards Perimount (n ¼ 2), and Medtronic Mosaic Cinch (n ¼ 2). All valves in this group were implanted in the supraannular position using pledgeted sutures. Five patients (22%) in the SU group underwent minimally invasive AVR through the mini–right thoracotomy, and the remaining patients (78%) underwent AVR through a full median sternotomy. Small-size Perceval prosthesis was used in all SU group patients. Cross-clamp times and CPB were significantly shorter in the SU group compared with the S group (47 21 minutes versus 67 15 minutes; 70 22 minutes versus 85 21 minutes, respectively; p < 0.05). One patient (4.5%) in the SU group needed a second pump run for repositioning because the prosthesis had been placed in too high a position, resulting in significant paravalvular leak. None of the 44 patients died intraoperatively.
The postoperative echocardiographic results (Table 3) show that the peak transvalvular gradient was lower in the SU compared with the S group (15 7 mm Hg versus 20 11 mm Hg, respectively; p ¼ 0.02; Fig 1). The indexed EOA was greater in the SU compared with the S group (1.12 0.2 cm2/m2 versus 0.82 0.1 cm2/m2, respectively; p < 0.05; Fig 2). Also, regression of left ventricular hypertrophy was better in the SU compared with the S group (93 21 g/m2 versus 106 14 g/m2, respectively; p ¼ 0.02; Fig 3). Regression analysis of left ventricle mass index differences between the two groups demonstrated a 9.8% percent change in favor of the SU group. The probability value was less than 0.05. In the SU group, early echocardiography demonstrated trivial paravalvular aortic insufficiency in 1 patient who did not require surgical intervention. No increase in the severity of aortic insufficiency was noted during follow-up.
Comment Prolonged life expectancy has increased the number of elderly, high-risk patients with a small aortic annulus referred for surgical AVR. These patients are at high risk of developing PPM with all its negative ramifications. Among all the risk factors leading to mortality in these patients, PPM is the only factor that can be avoided. In our study, sutureless bioprosthetic valves presented a favorable solution for those elderly patients with a small annulus. It increased the indexed EOA and reduced the incidence of PPM, which led to a better regression of left ventricle hypertrophy. It also reduced cross-clamp and CPB times. Our results are in accord with a recently published multicenter study, which also confirmed the efficacy of sutureless bioprostheses in elderly patients with a small annulus [8].
Early Results Early results are shown in Table 2. There was no 30-day mortality. Two patients (9%) in each group experienced an ischemic stroke with complete resolution of their neurologic impairment before discharge. One patient (4.5%) in the SU group needed a tracheostomy owing to respiratory failure and prolonged ventilation. Two patients experienced a wound infection: 1 in the S group had a deep sternal wound infection after median sternotomy that was treated successfully with sternoplasty, and 1 in the SU group had a superficial wound infection. Upper gastrointestinal bleeding occurred in 1 patient from each group and both required a blood transfusion.
Table 3. Midterm Echocardiographic Follow-Up
Variable
SU-AVR (n ¼ 22) n (%)
S-AVR (n ¼ 22) (n (%)
LV ejection fraction 0.57 0.13 0.60 0.07 AV mean gradient (mm Hg) 15 7 20 11 1.12 0.2 0.82 0.1 AV indexed EOA (cm2/m2) 93 21 106 14 LVMI (g/m2)
p Value 0.3 0.02 0.0001 0.02
AV ¼ aortic valve; LV ¼ left ventricular; LVMI ¼ left ventricular mass index; S-AVR ¼ stented aortic valve replacement; SU-AVR ¼ sutureless aortic valve replacement.
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SHALABI ET AL SUTURELESS VALVES IN SMALL AORTIC ANNULUS
Fig 1. A preoperative and postoperative comparison of the mean gradient between the two groups. (S-AVR ¼ stented aortic valve replacement; SU-AVR ¼ sutureless aortic valve replacement.)
Relief of left ventricular obstruction and mass regression constitute major factors in clinical improvement after AVR. Patient–prosthesis mismatch after AVR causes reduced regression of left ventricular hypertrophy, reduced coronary flow reserve, increased incidence of congestive heart failure, and increased risk of early and late mortality [9, 10]. The indexed EOA is the only variable that provides reliable information about the severity of PPM [11]. Assuming that a patient’s body surface area is not likely to change shortly before surgery, we need to increase the EOA of the implanted valve to minimize PPM after AVR. In contrast to a stented valve, the sutureless valve has no sewing ring, which increases the EOA and leads to improved hemodynamic results. In our study, the hemodynamic performance of the two groups showed a significant difference in favor of the SU group (15 7 mm Hg versus 20 11 mm Hg; p ¼ 0.02). The indexed EOA was significantly higher in the SU group (1.12 0.2 cm2/m2 versus 0.82 0.1 cm2/m2; p < 0.05). In other words, 76% of the patients in the S group had a moderate PPM. The prevalence of moderate PPM in the literature ranges between 20% and 75% [12]. In our SU group, postoperative regression of the left ventricular mass index was already more pronounced (with statistical significance) within less than a year (92 24 g/m2 versus 107 14 g/m2; p ¼ 0.02). The degree of preoperative left ventricular hypertrophy and the number of patients with hypertension were similar in both groups. Despite the significant decrease of the mean gradient in the S group, the decline of left ventricular hypertrophy was not noticeable. Previous studies have demonstrated that the impact of the indexed EOA on left ventricular mass regression is more important than the transvalvular
Fig 2. A preoperative and postoperative comparison of the indexed effective orifice between the two groups. (S-AVR ¼ stented aortic valve replacement; SU-AVR ¼ sutureless aortic valve replacement.)
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Fig 3. A preoperative and postoperative comparison of the left ventricular mass index between the two groups. (S-AVR ¼ stented aortic valve replacement; SU-AVR ¼ sutureless aortic valve replacement.)
gradient [11–13]. Lack of left ventricular hypertrophy regression affects functional capacity and mortality [14]. Transcatheter valve implantation in high-risk patients with severe aortic stenosis and a small aortic annulus also increases the indexed EOA and is associated with good postprocedural valve hemodynamics and clinical outcomes [15]. However, the PARTNER trial showed that the incidence of paravalvular leak is significantly higher after transcatheter valve implantation than after surgical AVR at both 1 and 2 years [16]. Paravalvular leak has been identified as an independent predictor of late mortality after transcatheter valve implantation [17]. Because of complete resection and decalcification of the native valve, the use of sutureless bioprosthesis in surgery also provides a much lower risk of postoperative paravalvular leak. The majority of patients in the S group (63%) received Mitroflow bioprostheses, which are known to avoid PPM and provide good hemodynamics in patients with a small aortic annulus [18]. Despite this, patients in the SU group had better hemodynamic results and a lower incidence of PPM. Another alternative treatment for a small aortic annulus is the implantation of smaller sized mechanical valves [19]. However, the risk of bleeding is unacceptably higher among elderly patients with mechanical compared with biologic valves, limiting the use of mechanical valves to younger patients [20]. Suture techniques (eg, pledgeted versus interrupted simple sutures) can affect the transvalvular gradient [21]. In our S group of patients, we used noneverting mattress suturing to position the prosthesis in the supraannular position and by doing so were able to oversize and maximize the EOA. Cardiopulmonary bypass and aortic cross-clamping duration influence patient outcomes. Both are independent predictors of 30-day postoperative mortality after adult cardiac surgery [22]. Implantations of stentless bioprostheses and aortic root replacement or enlargement require a longer learning period and are frequently associated with longer aortic cross-clamp times, which could increase morbidity and mortality, especially in elderly patients [23, 24]. In our study, the use of sutureless valve prostheses significantly reduced CPB and aortic cross-clamping procedure times by avoiding the need to use sutures to secure the bioprosthesis within the aortic annulus. Elderly patients with multiple comorbidities
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could benefit from reducing the length of time of the implantation itself and the overall duration of crossclamping. Patient–prosthesis mismatch is an independent factor of mortality after AVR. Moderate PPM is associated with increased mortality when left ventricular function is less than 50% but not when ventricular function is normal [25]. The mean indexed EOA in the S group was 0.82 0.1 cm2/m2 (moderate PPM). Five patients died (3 because of congestive heart failure) at late follow-up in the S group of patients. There was no mortality in the SU group during the follow-up period. Noteworthy is the fact that the clinical follow-up was significantly longer in the S group.
Limitations Both patient cohorts were small. It was not a prospective randomized study, and there was an unequal length of clinical follow-up between the two groups. The use of at least four different types of stented valves in the S group constitutes a major drawback because each valve has a different design and contributes to slight variations in the EOA.
Conclusions For elderly patients with a small aortic annulus, the use of sutureless bioprostheses provides improved hemodynamic performance in the short-term and midterm compared with stented bioprosthetic valves, and may significantly reduce the incidence of PPM. A randomized trial is required to meaningfully compare outcomes between conventional and sutureless AVR.
References 1. Rahimtoola SH. The problem of valve prosthesis-patient mismatch. Circulation 1978;58:20–4. 2. Dumesnil JG, Pibarot P. Prosthesis-patient mismatch and clinical outcomes: the evidence continues to accumulate. J Thorac Cardiovasc Surg 2006;131:952–5. 3. Jin XY, Zhang ZM, Gibson DG, Yacoub MH, Pepper JR. Effects of valve substitute on changes in left ventricular function and hypertrophy after aortic valve replacement. Ann Thorac Surg 1996;62:683–90. 4. Kappetein AP, Braun J, Baur LH, et al. Outcome and followup of aortic valve replacement with the freestyle stentless bioprosthesis. Ann Thorac Surg 2001;71:601–7. 5. Penaranda JG, Greason KL, Pislaru SV, et al. Aortic root enlargement in octogenarian patients results in less patient prosthesis mismatch. Ann Thorac Surg 2014;97:1533–8. 6. Shrestha M, Folliguet T, Meuris B, et al. Sutureless Perceval S aortic valve replacement: a multicenter, prospective pilot trial. J Heart Valve Dis 2009;18:698–702. 7. Pibarot P, Dumesnil JG. Prevention of valve prosthesispatient mismatch before aortic valve replacement: does it matter and is it feasible? Heart 2007;93:549–51.
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8. Villa E, Messina A, Laborde F, et al. Challenge for perceval: aortic valve replacement with small sutureless valves—a multicenter study. Ann Thorac Surg 2015;99:1248–54. 9. Pibarot P, Dumesnil JG. Hemodynamic and clinical impact of prosthesis-patient mismatch in the aortic valve position and its prevention. J Am Coll Cardiol 2000;36:1131–41. 10. Rajappan K, Rimoldi OE, Camici PG, Bellenger NG, Pennell DJ, Sheridan DJ. Functional changes in coronary microcirculation after valve replacement in patients with aortic stenosis. Circulation 2003;107:3170–5. 11. Bleiziffer S, Eichinger WB, Hettich I, et al. Prediction of valve prosthesis-patient mismatch prior to aortic valve replacement: which is the best method? Heart 2007;93:615–20. 12. Tasca G, Brunelli F, Cirillo M, et al. Impact of valve prosthesis-patient mismatch on left ventricular mass regression following aortic valve replacement. Ann Thorac Surg 2005;79:505–10. 13. Del Rizzo DF, Abdoh A, Cartier P, Doty D, Westaby S. Factors affecting LV mass regression following AVR with stentless valves. Semin Thorac Cardiovasc Surg 1999;11(Suppl 1):114–20. 14. Sullivan JM, Vander Zwaag RV, el-Zeky F, Ramanathan KB, Mirvis DM. Left ventricular hypertrophy: effect on survival. J Am Coll Cardiol 1993;22:508–13. 15. Kalavrouziotis D, Rod es-Cabau J, Bagur R, et al. Transcatheter aortic valve implantation in patients with severe aortic stenosis and small aortic annulus. J Am Coll Cardiol 2011;58:1016–24. 16. Kodali SK, Williams MR, Smith CR, et al, PARTNER Trial Investigators. Two-year outcomes after transcatheter or surgical aortic-valve replacement. N Engl J Med 2012;366:1686–95. 17. Tamburino C, Capodanno D, Ramondo A, et al. Incidence and predictors of early and late mortality after transcatheter aortic valve implantation in 663 patients with severe aortic stenosis. Circulation 2011;123:299–308. 18. Jamieson WR, Forgie WR, Hayden RI, et al. Hemodynamic performance of mitroflow aortic pericardial bioprostheses— optimizing management for the small aortic annulus. Thorac Cardiovasc Surg 2010;58:69–75. 19. Zhao D, Wang C, Hong T, Pan C, Guo C. Application of Regent mechanical valve in patients with small aortic annulus: 3-year follow-up. J Cardiothorac Surg 2012;7:88. 20. Florath I, Albert A, Rosendahl U, Alexander T, Ennker IC, Ennker J. Mid term outcome and quality of life after aortic valve replacement in elderly people: mechanical versus stentless biological valves. Heart 2005;91:1023–9. 21. Tabata M, Shibayama K, Watanabe H, Sato Y, Fukui T, Takanashi S. Simple interrupted suturing increases valve performance after aortic valve replacement with a small supra-annular bioprosthesis. J Thorac Cardiovasc Surg 2014;147:321–5. 22. Nissinen J, Biancari F, Wistbacka JO, et al. Safe time limits of aortic cross-clamping and cardiopulmonary bypass in adult cardiac surgery. Perfusion 2009;24:297–305. 23. Dhareshwar J, Sundt TM III, Dearani JA, Schaff HV, Cook DJ, Orszulak TA. Aortic root enlargement: what are the operative risks? J Thorac Cardiovasc Surg 2007;134:916–24. 24. Peterson MD, Borger MA, Feindel CM, David TE. Aortic annular enlargement during aortic valve replacement: improving results with time. Ann Thorac Surg 2007;83:2044–9. 25. Mohty D, Dumesnil JG, Echahidi N, et al. Impact of prosthesis-patient mismatch on long-term survival after aortic valve replacement: influence of age, obesity, and left ventricular dysfunction. J Am Coll Cardiol 2009;53:39–47.
Background. Aortic valve replacement, particularly in elderly patients with small aortic annulus, could lead to patient–prosthesis mismatch. Sutureless bioprosthesis could be an ideal solution for these patients. We compared results of aortic valve replacement with sutureless versus stented bioprosthetic valves. Methods. Of the 63 patients undergoing aortic valve replacement with sutureless bioprosthesis between 2011 and 2014 in our department, 22 (20 women, 77 ± 6 years) had a small annulus less than 21 mm (sutureless group). They were matched for sex, age, body surface area, and left ventricular ejection fraction with 22 patients (20 women, 79 ± 6 years) undergoing stented bioprosthesis valve replacement (stented group). Body mass index and body surface area were 28 ± 5 kg/m2 and 28 ± 3 kg/m2 (p [ 0.9), 1.6 ± 0.2 m2 and 1.6 ± 0.1 m2 (p [ 0.9), in the sutureless and stented groups, respectively. Logistic EuroSCOREs were similar between groups. Results. Postoperative peak transvalvular gradient was lower in the sutureless group (15 ± 7 mm Hg versus 20 ± 11 mm Hg; p [ 0.02). The indexed effective
orifice area was greater in the sutureless group (1.12 ± 0.2 cm2/m2 versus 0.82 ± 0.1 cm2/m2; p < 0.05). Aortic cross-clamp and cardiopulmonary bypass times were 47 ± 21 and 67 ± 15 minutes, respectively (p < 0.05) in the sutureless group versus 70 ± 22 and 85 ± 21 minutes, respectively (p [ 0.02) in the stented group. Intensive care unit stay, hospitalization, and major complications were not significantly different between groups. At follow-up, regression of left ventricular hypertrophy was better in the sutureless group (93 ± 21 g/m2 versus 106 ± 14 g/m2; p [ 0.02). Conclusions. Sutureless bioprosthetic valves demonstrate improved hemodynamic performance compared with stented valves in elderly patients with small aortic annulus, providing better regression of left ventricular hypertrophy and decreased rates of patient–prosthesis mismatch. Aortic cross-clamp and cardiopulmonary bypass times are also decreased.
S
of a stentless valve is technically more complicated than that of a stented valve. It requires longer cardiopulmonary bypass (CPB) and cross-clamp times. Furthermore, increased in-hospital mortality has been reported with stentless compared with stented valves [4]. Aortic root enlargement increases the annulus size in patients with a small annulus, improves hemodynamic performance, and reduces PPM. However, aortic root enlargement also increases aortic cross-clamp time, which in inexperienced hands could increase morbidity and mortality [5]. Sutureless valves have no sewing ring, which not only offers a larger EOA for any given size but also provides hemodynamic advantages like stentless prosthesis without increased difficulty during surgical implantation. Therefore, the use of a sutureless prosthesis may provide a relatively easy and safe solution for patients with a small aortic annulus. The aim of this study was to compare the hemodynamic performance and incidence of PPM in elderly patients with a small aortic root (<21 mm) undergoing either sutureless AVR with a Perceval S small aortic valve (Sorin Biomedica, Cardio, Saluggia, Italy) or conventional sutured bioprosthesis AVR.
urgical aortic valve replacement (AVR) is a definitive and proven therapy for patients with symptomatic severe aortic stenosis. Most stented prosthetic aortic valves offer an effective orifice area (EOA) less than that of the native valve because of the area reduced by the structural components of the new valve. Therefore, patients with a small aortic annulus are particularly threatened by the appearance of a patient–prosthesis mismatch (PPM), in which the EOA of a normally functioning heart valve prosthesis is too small in relation to the patient’s body size. This condition has clinical and hemodynamic implications, such as freedom from heart failure, left ventricular mass regression, and late survival [1–3]. To avoid PPM, patients with a small aortic annulus could undergo implantation of a stentless bioprosthesis and aortic root enlargement. However, the implantation
Accepted for publication Jan 4, 2016. *Drs Shalabi and Spiegelstein contributed equally to this work. Address correspondence to Dr Raanani, Department of Cardiac Surgery, Chaim Sheba Medical Center, Tel-Hashomer, 52621, Israel; email: ehud. [email protected].
Ó 2016 by The Society of Thoracic Surgeons Published by Elsevier
(Ann Thorac Surg 2016;-:-–-) Ó 2016 by The Society of Thoracic Surgeons
0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2016.01.003
2
SHALABI ET AL SUTURELESS VALVES IN SMALL AORTIC ANNULUS
Material and Methods Patient Population Between December 2011 and October 2014, 63 patients underwent sutureless AVR at our medical center. We identified 22 patients with severe symptomatic aortic stenosis and small aortic annulus less than 21 mm, who underwent isolated sutureless AVR (SU group). These patients were matched for sex, age, body surface area, and left ventricular ejection fraction with 22 other patients with a small aortic annulus (selected from a group of 147 patients who underwent isolated AVR with sutured bioprosthesis size 19 to 21 mm). This second group of 22 patients underwent isolated stented sutured AVR (S group). Preoperative, operative, and postoperative data were prospectively collected at our departmental database unit. All patients were followed up in the outpatient center clinically and echocardiographically. A telephone interview was required for those lost to ambulatory follow-up. Clinical follow-up was 14 11 months in the SU group and 45 22 months in the S group (p < 0.01). Because the clinical follow-up in the S group was significantly longer, we compared only midterm echocardiographic follow-up: 9 2 months in the SU group and 8 4 months in the S group (p ¼ 0.32).
Surgical Procedures All patients from the S group underwent surgery through a median sternotomy. In the SU group, surgery was performed either by means of a full sternotomy or a mini– right thoracotomy. Standard CPB was established by cannulation of the ascending aorta and the right atrium in the sternotomy patients, whereas femoral cannulation was performed in the mini–right thoracotomy approach. Myocardial protection was achieved by using antegrade cold blood cardioplegia. Owing to the high profile of the prosthesis, sutureless AVR was performed through the high transverse aortotomy approximately 1 to 2 cm above the sinotubular junction. The valve was excised, and the annulus was decalcified in both surgical groups. Patients were monitored intraoperatively with transesophageal echocardiography for the management of CPB and prosthesis evaluation. Implantation techniques and details regarding the Perceval S valves have been previously described [6]. All stented prostheses were implanted in the supraannular position with noneverting interrupted mattress sutures.
Definition of Patient–Prosthesis Mismatch Patient–prosthesis mismatch was calculated by the echocardiographically determined EOA indexed for the body surface area. Severe PPM was defined as an indexed EOA of less than 0.65 cm2/m2, and moderate PPM was defined as an indexed EOA between 0.65 and 0.85 cm2/m2 [7].
Statistical Analysis All statistical analyses were performed with SPSS software (version 21; IBM Corp, Armonk, NY). Values are expressed as mean standard deviation or as a percentage. Continuous variables were compared by the
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Wilcoxon test, and categorical variables were compared using the McNamara test. A probability value of less than 0.05 was considered significant.
Results Patient Characteristics and Preoperative Echocardiographic Data Of the 22 patients in each group, the majority (90%) were female. Mean age was 77 6 years and 79 6 years in the SU group and S group, respectively (p ¼ 0.1). Logistic EuroSCORE I was 15 16 and 14 16 in the SU group and S group, respectively (p ¼ 0.6). Patient characteristics and preoperative echocardiographic data for both patient groups are listed in Table 1.
Operative Data Relevant operative data are summarized in Table 2. The majority of patients in the S group received Sorin Table 1. Patients and Preoperative Echocardiographic Data
Variable Age (y) Body mass index (kg/m2) Body surface area (cm2/m2) COPD (n, %) Chronic renal failure (n, %) Diabetes mellitus (n, %) Female Hypertension (n, %) Logistic EuroSCORE (%) NYHA functional class III/IV (n, %) Peripheral vascular disease (n, %) 2 (9%) Prior cerebrovascular accident (n, %) Pulmonary hypertension > 60 mm Hg (n, %) Preoperative echocardiographic data LV ejection fraction AV mean gradient (mm Hg) AV peak gradient (mm Hg) Aortic valve area (cm2) Annulus size (mm) Indexed EOA (cm2/m2) Interventricular septum (mm) LVMI (g/m2)
SU-AVR (n ¼ 22) n (%)
S-AVR (n ¼ 22) n (%)
p Value
77 6 28 5 1.6 0.2 1 (4.5%) 2 (9%)
79 6 28 3 1.6 0.1 2 (9%) 2 (9%)
0.1 0.90 0.9 0.9 1
7 (32%)
8 (36%)
0.9
20 (0.9%) 19 (86%) 15 16 12 (54%)
20 (90%) 18 (82%) 14 16 12 (55%)
1 0.9 0.6 1
0
0.6
4 (18%)
2 (9%)
0.7
1 (5%)
1 (5%)
1
0.59 0.10 0.56 0.09 47 19 47 12 76 0.66 19 0.41 14 112
30 78 20 0.1 0.67 0.1 0.8 18.6 1.4 03 0.42 0.2 2.5 15 1.7 17 115 22
0.11 0.6 0.8 0.9 0.25 0.9 0.12 0.6
AV ¼ aortic valve; AVR ¼ aortic valve replacement; COPD ¼ chronic obstructive pulmonary disease; EOA ¼ effective orifice area; EuroSCORE ¼ European System for Cardiac Operative Risk Evaluation; LV ¼ left ventricle; LVMI ¼ left ventricular mass index; NYHA ¼ New York Heart Association; S ¼ stented; SU ¼ sutureless.
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SHALABI ET AL SUTURELESS VALVES IN SMALL AORTIC ANNULUS
Table 2. Operative Data and Early Results
Variable
SU-AVR (n ¼ 22) n (%)
S-AVR (n ¼ 22) n (%)
Cross-clamp time (min) 47 21 67 15 Cardiopulmonary 70 22 85 21 bypass (min) Repositioning (n, %) 1 (5%) NA Right minimal 5 (22%) 0 thoracotomy (n, %) Early results Mortality 0 0 Transient ischemic 2 (9%) 2 (9%) attack (n, %) Permanent pacemaker (n, %) 1 (4.5%) 0 Sternal wound 1 (4.5%) 1 (4.5%) infection (n, %) Atrial fibrillation (n, %) 1 (4.5%) 4 (18%) Gastrointestinal 1 (4.5%) 1 (4.5%) bleeding (n,%) Post pericardioectomy 2 (9%) 0 syndrome (n, %) Intensive care unit (hours) 45 (24–63) 40 (18–107) Hospitalization time (days) 6.5 (5–9) 7 (6–10)
p Value 0.0008 0.02 NA 0.06
3
In the SU group, 2 patients underwent thoracocentesis for a pleural effusion after a minithoracotomy. One patient in the SU group underwent permanent pacemaker implantation because of complete atrioventricular block. Four patients in the S group compared with 1 in the SU group had postoperative atrial fibrillation. They were treated with amiodarone and returned to sinus rhythm. Intensive care unit and hospitalization times were similar in both groups.
Midterm Echocardiographic Follow-Up 1 1 0.9 1 0.37 1 0.85 0.75 1
NA ¼ not available; S-AVR ¼ stented aortic valve replacement; SU-AVR ¼ sutureless aortic valve replacement.
Mitroflow (n ¼ 14), and the remainder received Carpentier Edwards Magna Ease (n ¼ 4), Carpentier Edwards Perimount (n ¼ 2), and Medtronic Mosaic Cinch (n ¼ 2). All valves in this group were implanted in the supraannular position using pledgeted sutures. Five patients (22%) in the SU group underwent minimally invasive AVR through the mini–right thoracotomy, and the remaining patients (78%) underwent AVR through a full median sternotomy. Small-size Perceval prosthesis was used in all SU group patients. Cross-clamp times and CPB were significantly shorter in the SU group compared with the S group (47 21 minutes versus 67 15 minutes; 70 22 minutes versus 85 21 minutes, respectively; p < 0.05). One patient (4.5%) in the SU group needed a second pump run for repositioning because the prosthesis had been placed in too high a position, resulting in significant paravalvular leak. None of the 44 patients died intraoperatively.
The postoperative echocardiographic results (Table 3) show that the peak transvalvular gradient was lower in the SU compared with the S group (15 7 mm Hg versus 20 11 mm Hg, respectively; p ¼ 0.02; Fig 1). The indexed EOA was greater in the SU compared with the S group (1.12 0.2 cm2/m2 versus 0.82 0.1 cm2/m2, respectively; p < 0.05; Fig 2). Also, regression of left ventricular hypertrophy was better in the SU compared with the S group (93 21 g/m2 versus 106 14 g/m2, respectively; p ¼ 0.02; Fig 3). Regression analysis of left ventricle mass index differences between the two groups demonstrated a 9.8% percent change in favor of the SU group. The probability value was less than 0.05. In the SU group, early echocardiography demonstrated trivial paravalvular aortic insufficiency in 1 patient who did not require surgical intervention. No increase in the severity of aortic insufficiency was noted during follow-up.
Comment Prolonged life expectancy has increased the number of elderly, high-risk patients with a small aortic annulus referred for surgical AVR. These patients are at high risk of developing PPM with all its negative ramifications. Among all the risk factors leading to mortality in these patients, PPM is the only factor that can be avoided. In our study, sutureless bioprosthetic valves presented a favorable solution for those elderly patients with a small annulus. It increased the indexed EOA and reduced the incidence of PPM, which led to a better regression of left ventricle hypertrophy. It also reduced cross-clamp and CPB times. Our results are in accord with a recently published multicenter study, which also confirmed the efficacy of sutureless bioprostheses in elderly patients with a small annulus [8].
Early Results Early results are shown in Table 2. There was no 30-day mortality. Two patients (9%) in each group experienced an ischemic stroke with complete resolution of their neurologic impairment before discharge. One patient (4.5%) in the SU group needed a tracheostomy owing to respiratory failure and prolonged ventilation. Two patients experienced a wound infection: 1 in the S group had a deep sternal wound infection after median sternotomy that was treated successfully with sternoplasty, and 1 in the SU group had a superficial wound infection. Upper gastrointestinal bleeding occurred in 1 patient from each group and both required a blood transfusion.
Table 3. Midterm Echocardiographic Follow-Up
Variable
SU-AVR (n ¼ 22) n (%)
S-AVR (n ¼ 22) (n (%)
LV ejection fraction 0.57 0.13 0.60 0.07 AV mean gradient (mm Hg) 15 7 20 11 1.12 0.2 0.82 0.1 AV indexed EOA (cm2/m2) 93 21 106 14 LVMI (g/m2)
p Value 0.3 0.02 0.0001 0.02
AV ¼ aortic valve; LV ¼ left ventricular; LVMI ¼ left ventricular mass index; S-AVR ¼ stented aortic valve replacement; SU-AVR ¼ sutureless aortic valve replacement.
4
SHALABI ET AL SUTURELESS VALVES IN SMALL AORTIC ANNULUS
Fig 1. A preoperative and postoperative comparison of the mean gradient between the two groups. (S-AVR ¼ stented aortic valve replacement; SU-AVR ¼ sutureless aortic valve replacement.)
Relief of left ventricular obstruction and mass regression constitute major factors in clinical improvement after AVR. Patient–prosthesis mismatch after AVR causes reduced regression of left ventricular hypertrophy, reduced coronary flow reserve, increased incidence of congestive heart failure, and increased risk of early and late mortality [9, 10]. The indexed EOA is the only variable that provides reliable information about the severity of PPM [11]. Assuming that a patient’s body surface area is not likely to change shortly before surgery, we need to increase the EOA of the implanted valve to minimize PPM after AVR. In contrast to a stented valve, the sutureless valve has no sewing ring, which increases the EOA and leads to improved hemodynamic results. In our study, the hemodynamic performance of the two groups showed a significant difference in favor of the SU group (15 7 mm Hg versus 20 11 mm Hg; p ¼ 0.02). The indexed EOA was significantly higher in the SU group (1.12 0.2 cm2/m2 versus 0.82 0.1 cm2/m2; p < 0.05). In other words, 76% of the patients in the S group had a moderate PPM. The prevalence of moderate PPM in the literature ranges between 20% and 75% [12]. In our SU group, postoperative regression of the left ventricular mass index was already more pronounced (with statistical significance) within less than a year (92 24 g/m2 versus 107 14 g/m2; p ¼ 0.02). The degree of preoperative left ventricular hypertrophy and the number of patients with hypertension were similar in both groups. Despite the significant decrease of the mean gradient in the S group, the decline of left ventricular hypertrophy was not noticeable. Previous studies have demonstrated that the impact of the indexed EOA on left ventricular mass regression is more important than the transvalvular
Fig 2. A preoperative and postoperative comparison of the indexed effective orifice between the two groups. (S-AVR ¼ stented aortic valve replacement; SU-AVR ¼ sutureless aortic valve replacement.)
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Fig 3. A preoperative and postoperative comparison of the left ventricular mass index between the two groups. (S-AVR ¼ stented aortic valve replacement; SU-AVR ¼ sutureless aortic valve replacement.)
gradient [11–13]. Lack of left ventricular hypertrophy regression affects functional capacity and mortality [14]. Transcatheter valve implantation in high-risk patients with severe aortic stenosis and a small aortic annulus also increases the indexed EOA and is associated with good postprocedural valve hemodynamics and clinical outcomes [15]. However, the PARTNER trial showed that the incidence of paravalvular leak is significantly higher after transcatheter valve implantation than after surgical AVR at both 1 and 2 years [16]. Paravalvular leak has been identified as an independent predictor of late mortality after transcatheter valve implantation [17]. Because of complete resection and decalcification of the native valve, the use of sutureless bioprosthesis in surgery also provides a much lower risk of postoperative paravalvular leak. The majority of patients in the S group (63%) received Mitroflow bioprostheses, which are known to avoid PPM and provide good hemodynamics in patients with a small aortic annulus [18]. Despite this, patients in the SU group had better hemodynamic results and a lower incidence of PPM. Another alternative treatment for a small aortic annulus is the implantation of smaller sized mechanical valves [19]. However, the risk of bleeding is unacceptably higher among elderly patients with mechanical compared with biologic valves, limiting the use of mechanical valves to younger patients [20]. Suture techniques (eg, pledgeted versus interrupted simple sutures) can affect the transvalvular gradient [21]. In our S group of patients, we used noneverting mattress suturing to position the prosthesis in the supraannular position and by doing so were able to oversize and maximize the EOA. Cardiopulmonary bypass and aortic cross-clamping duration influence patient outcomes. Both are independent predictors of 30-day postoperative mortality after adult cardiac surgery [22]. Implantations of stentless bioprostheses and aortic root replacement or enlargement require a longer learning period and are frequently associated with longer aortic cross-clamp times, which could increase morbidity and mortality, especially in elderly patients [23, 24]. In our study, the use of sutureless valve prostheses significantly reduced CPB and aortic cross-clamping procedure times by avoiding the need to use sutures to secure the bioprosthesis within the aortic annulus. Elderly patients with multiple comorbidities
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could benefit from reducing the length of time of the implantation itself and the overall duration of crossclamping. Patient–prosthesis mismatch is an independent factor of mortality after AVR. Moderate PPM is associated with increased mortality when left ventricular function is less than 50% but not when ventricular function is normal [25]. The mean indexed EOA in the S group was 0.82 0.1 cm2/m2 (moderate PPM). Five patients died (3 because of congestive heart failure) at late follow-up in the S group of patients. There was no mortality in the SU group during the follow-up period. Noteworthy is the fact that the clinical follow-up was significantly longer in the S group.
Limitations Both patient cohorts were small. It was not a prospective randomized study, and there was an unequal length of clinical follow-up between the two groups. The use of at least four different types of stented valves in the S group constitutes a major drawback because each valve has a different design and contributes to slight variations in the EOA.
Conclusions For elderly patients with a small aortic annulus, the use of sutureless bioprostheses provides improved hemodynamic performance in the short-term and midterm compared with stented bioprosthetic valves, and may significantly reduce the incidence of PPM. A randomized trial is required to meaningfully compare outcomes between conventional and sutureless AVR.
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