Asian Cardiovasc Thorac Ann 2006;14:128-133
© 2006 Asia Publishing EXchange Ltd
Continuous Suture Technique for Freedom Stentless Valve: Reduced Crossclamp Time
Sven Beholz, PhD,
Simon Dushe, MD,
Wolfgang Konertz, PhD
Department of Cardiovascular Surgery, Charité–University Medicine Berlin, Berlin, Germany
For reprint information contact: Sven Beholz, PhD Tel: 49 30 450 522 196 Fax: 49 30 450 522 921 Email: sven.beholz{at}charite.de, Department of Cardiovascular Surgery, Charité-University Medicine Berlin, Luisenstr. 65, Berlin 10117, Germany.
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ABSTRACT
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The Pericarbon Freedom stentless valve has shown excellent hemodynamics. A continuous suture technique at the inflow site may reduce cardiopulmonary bypass and crossclamp times and affect postoperative hemodynamics. In a prospective case-matched study, interrupted and continuous suture line techniques were used in 68 and 71 patients, respectively. Isolated valve replacement was performed in 70.4% of the continuous suture group and 67.6% of the interrupted suture group. Hemodynamic data were obtained by echocardiography (mean and peak gradients, regurgitation) at discharge and after 1 year. Overall mortality was 5.0% and due to non-valve-related causes. Bypass and crossclamp times were shorter by 22.4 and 20.6 min, respectively, in the continuous suture group. The suture technique at the inflow site did not result in significant differences in the mean (11.8 ± 6.3 vs. 12.5 ± 6.2 mm Hg) or peak gradients (21.0 ± 9.6 vs. 22.0 ± 10.9 mm Hg), or degree of regurgitation. Follow-up showed a further decrease in the gradients.
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INTRODUCTION
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In the elderly, aortic stentless bioprostheses have shown superior hemodynamics compared to stented bioprostheses.1 After the 1st and 2nd generations of tissue valves constructed mainly from porcine aortic valves, 3rd generation tissue valves are now available. These prostheses are made from pericardial tissue of equine or bovine origin, with modern anti-calcification treatment to overcome postoperative structural deterioration.2 The Pericarbon Freedom stentless valve (Sorin, Saluggia, Italy) is truly stentless, formed from two sheets of bovine pericardium sewn together in a cylindrical shape with threads covered by turbostratic carbon.3 The pericardium is fixed with glutaraldehyde and then detoxified using homocysteic acid to cover the remaining free aldehyde groups. The valve is stored in an antibiotic solution ready for use, and does not require rinsing. It has shown excellent hemodynamics in the early and midterm postoperative course.4 Due to its stentless construction, the valve requires two suture lines for subcoronary implantation: one at the inflow site of the valve to attach it in the left ventricular outflow tract (LVOT), and another to connect the outflow site of the prosthesis with the aortic wall below the coronary ostia. While the second suture line is usually a continuous suture of 4/0 or 5/0 polypropylene, two different techniques are possible for fixation in the LVOT: a continuous suture of 3/0 or 4/0 polypropylene, or an interrupted line of 2/0 or 3/0 braided polyester sutures.5 The aim of this study was to investigate whether there is a difference in early postoperative hemodynamic performance between the 2 implantation techniques, and if there is any substantial difference in crossclamp and cardiopulmonary bypass (CPB) times.
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PATIENTS AND METHODS
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The study was conducted as a non-randomized case-matched clinical trial in all patients undergoing isolated or combined aortic valve replacement from September 2001 to January 2004. The patients were assigned to the continuous suture group or the interrupted suture group according to age, sex, weight, height, and left ventricular ejection fraction. All patients gave written informed consent.
The patients were operated on under general anesthesia via a median sternotomy with normothermic CPB. Concomitant procedures were performed prior to valve replacement, except proximal anastomoses of saphenous vein grafts, which were undertaken immediately prior to declamping the aorta. Intermittent warm antegrade cardioplegia was applied to the aortic root, and after a transverse aortotomy, directly to the coronary ostia.6 After aortotomy, thorough resection of the leaflets and any calcified structures was carried out. Sizing was based on the diameter of the annulus and the sinotubular junction: if the size of the sinotubular junction did not exceed 20% of the diameter of the annulus, the latter was chosen as the valve size. In the case of a bigger discrepancy between the sinotubular junction and the annulus, the valve was one size larger than the annulus and proper aortorrhaphy was performed with closure of the aortotomy. The intraoperative pathology did not affect the preoperative choice of implantation technique. In the interrupted suture group, the prosthesis was fixed in the LVOT using 18 to 30 (mean, 21.3 ± 2.5) single 2/0 braided polyester sutures without reinforcement. Before tying the sutures, the valve was inverted into the LVOT according to the instructions for use. In the continuous suture group, a single running 3/0 polypropylene suture was used for fixation. In both groups, after eversion of the valve, the outflow site of the valve was fixed to the aortic root using a running 4/0 polypropylene suture in a subcoronary fashion. After closure of the aortotomy and release of the crossclamp, intraoperative transesophageal echocardiography was used to monitor de-airing of the heart and confirm the proper functioning of the valve. Patients were then weaned from CPB and transferred to the intensive care unit.
Besides basic demographic data and aortic valve pathology, the duration of CPB and aortic crossclamping was monitored. The preoperative risk was calculated according to the logistic EuroSCORE.7 Transthoracic echocardiography was performed prior to the operation, at discharge, and one year postoperatively to obtain mean and peak gradients. The grade of regurgitation was also noted.
Data were expressed as mean ± standard deviation. For statistical analysis, the Mann-Whitney U test and Wilcoxon test for unpaired groups were used. A p value below 0.05 was considered statistically significant.
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RESULTS
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In the 139 consecutive patients who underwent aortic valve replacement with the Pericarbon Freedom stentless valve, an interrupted suture line was used in 68 and a continuous suture line technique was applied in 71 (Table 1
). There were no significant differences between groups except in the underlying pathology: 9 patients suffering from acute endocarditis with or without infection of the annulus, of whom 5 had ring abscesses after previous valve replacement, were included in the interrupted suture group, whereas only one patient with incidental intraoperatively diagnosed endocarditis of one leaflet was included in the continuous suture group. Due to this difference, the mean preoperative regurgitation grade was significantly higher in the interrupted suture group, although the number of patients with regurgitation was comparable (Table 1). There was no significant difference in predicted mortality according to the logistic EuroSCORE: the high score for endocarditis and re-operation in the interrupted suture group was balanced by a slightly older age, slightly lower ejection fraction, more urgent cases, and higher comorbidity with respect to peripheral vascular disease and chronic obstructive pulmonary disease in the continuous suture group. Isolated valve replacements and concomitant procedures are listed in Table 2. Valve sizes ranged from 21 to 29 mm in both groups (Figure 1), with a mean valve size of 26.6 ± 2.2 mm in the interrupted suture group and 26.4 ± 1.9 mm in the continuous suture group, p > 0.05. The overall mean valve size was 26.5 ± 2.1 mm; median, 27 mm.
Postoperative echocardiographic evaluation showed a decrease in mean and peak gradients related to valve size (Figure 2), but no significant difference between the groups (Figure 3). Mean postoperative regurgitation was 0.14 ± 0.40 in the interrupted suture group, while there was no regurgitation in the continuous suture group (Figure 4). No paravalvular leak was found in either group.
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Figure 3. Echocardiographic mean and peak gradients across the aortic prosthesis according to the inflow suture technique.
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There was an overall mortality of 5.0%: 4 patients died in the interrupted suture group and 3 in the continuous suture group, none of these deaths was valve-related (Table 3). There were 5 re-operations: 3 due to partial valve thrombosis in patients with coagulation disorders, 1 in a case of recurrent endocarditis, and 1 because of a membranous ventricular septal defect (Table 3). Lengths of hospital and intensive care unit stay were comparable. There was only one case of permanent stroke in the continuous suture group (Table 3).
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Table 3. Postoperative Mortality and Morbidity in Continuous Suture (n = 71) and Interrupted Suture (n = 68) Groups
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At the end of the study period, 92 patients had reached the one-year follow-up point; 12 declined further echocardiography for a variety of reasons; therefore, one-year follow-up was available in 73 of 85 surviving patients (85.9% complete). Transthoracic echocardiography at one year showed a significant decrease in mean and peak gradients compared to discharge (Figure 5). All patients had none or trivial transvalvular regurgitation, and no paravalvular leak was found at follow-up examination.
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Figure 5. Transvalvular pressure gradients at discharge and at 1-year follow-up, *p < 0.05, **p < 0.01.
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Crossclamp time and the duration of CPB were significantly reduced in the continuous suture group. The overall mean reduction in CPB time was 22.4 min, and the decrease in crossclamp time was 20.6 min (Table 4).
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Table 4. Crossclamp Times and Duration of Cardiopulmonary Bypass in Continuous Suture (n = 71) and Interrupted Suture (n = 68) Groups
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DISCUSSION
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Stentless bioprostheses in the aortic position have shown superior hemodynamics in comparison to stented valves.1 Subcoronary implantation, even in the elderly, can be performed with acceptable risk.8 Due to improved ventricular reverse remodeling, the long-term survival in patients with stentless aortic valves seems to be increased compared to those with stented valves.9 After using stentless porcine valves with various methods of fixation, stentless pericardial valves have found wide acceptance.2 The Pericarbon Freedom stentless valve is constructed from bovine pericardium fixed with glutaraldehyde and detoxified with homocysteic acid.3 In the Pericarbon More stented valve (Sorin, Saluggia, Italy), this material has shown excellent long-term results with regard to structural deterioration and freedom from re-operation.10,11 The Pericarbon Freedom stentless valve has also shown excellent hemodynamic performance in the short and medium term.4,12
Although the two techniques for implantation of the Pericarbon Freedom stentless valve have been described in detail previously, there has been no information on whether a continuous suture technique at the inflow site of the valve may increase postoperative gradients due to a pursestring effect, and whether the choice of implantation technique may influence the duration of crossclamping or CPB.5 Especially in combined procedures in the elderly, a significant reduction of these times may decrease the operative risk and thus may influence the choice of valve prosthesis. Continuous suture techniques can easily be performed with the Pericarbon Freedom stentless valve as it may be inverted into the LVOT; in the case of porcine stentless valves, the sensitive leaflets may be affected at the top of the commissures.5
Mean and peak gradients have proved to be reliable parameters for the investigation of postoperative hemodynamics. Our data demonstrated excellent hemodynamic performance in the early postoperative phase, as shown by low mean and peak gradients at rest (Figure 2
). We did not perform these investigations during exercise as patients do not tolerate it well in this early phase of recovery. Due to the sizing policy according to the sinotubular junction, with a mean valve size of 26.5 ± 2.1 mm (Figure 1), regurgitation could be avoided in both groups (Figure 4). There was no statistical difference between the implantation techniques with respect to mean and peak gradients overall, nor in the different valve sizes (Figures 3 and 4).
Although follow-up was not complete after one year, a significant reduction of peak and mean gradient could be observed (Figure 5). This finding confirms the results of Bonacchi and colleagues12 who described decreases in mean gradients of 14.0 to 8.7 mm Hg after 6 months. This reduction of mean gradient may be caused on one hand by the resorption of a hematoma between the aortic wall and the prosthesis, which is frequently seen in immediate postoperative echocardiography. On the other hand, this decrease may result from reverse remodeling of the hypertrophied LVOT, thus resulting in reduced flow velocity.13 As the adverse effects of CPB, known as the "whole body inflammatory reaction" are time-dependent, increased CPB time may lead to increased morbidity.14 Furthermore, longer crossclamp times give increased risk of postoperative low output syndrome, especially in combined procedures in the elderly.15 In our study, the continuous suture technique substantially reduced CPB and crossclamp times. Besides the hemodynamic properties of the Pericarbon Freedom stentless valve, such a reduction is valuable in combined as well as isolated procedures.
There were some limitations of the study as it was not randomized but case-matched. Despite this, both groups showed similar characteristics except for the number of patients with endocarditis. It was concluded that the Pericarbon Freedom stentless valve offers excellent hemodynamics in the early postoperative course, with no difference in hemodynamics due to a continuous or interrupted suture line technique at the inflow site of the graft. A significant reduction in crossclamp time and duration of cardiopulmonary bypass can be achieved with the continuous suture technique.
Presented at the 12th Annual Meeting of the Asian Society for Cardiovascular Surgery, April 19–22, 2004, Istanbul, Turkey.
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REFERENCES
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- Jin XY, Gibson DG, Yacoub MH, Pepper JR. Perioperative assessment of aortic homograft, Toronto stentless valve, and stented valve in the aortic position. Ann Thorac Surg 1995;60(2 Suppl):S395–401.[Medline]
- Konertz W. Stentless aortic xenograft heart valves. Asian Cardiovasc Thorac Ann 2003;11:1–2.[Free Full Text]
- Stacchino C, Bona G, Rinaldi S, Vallana F. Design and performance characteristics of the Pericarbon Stentless valve. J Heart Valve Dis 1995;4 Suppl 1:S102–5.
- Jin XY, Westaby S. Pericardial and porcine stentless aortic valves: are they hemodynamically different? Ann Thorac Surg 2001;71(5 Suppl):S311–4.[Abstract/Free Full Text]
- Westaby S, Jin XY, Vaccari G, Katsumata T. The Sorin stentless pericardial valve: implant technique and hemodynamic profile. Semin Thorac Cardiovasc Surg 1999;11(4 Suppl 1):62–8.[Medline]
- Calafiore AM, Teodori G, Mezzetti A, Bosco G, Verna AM, Di Giammarco G, et al. Intermittent antegrade warm blood cardioplegia. Ann Thorac Surg 1995;59:398–402.[Abstract/Free Full Text]
- Roques F, Nashef SA, Michel P, Gauducheau E, de Vincentiis C, Baudet E, et al. Risk factors and outcome in European cardiac surgery: analysis of the EuroSCORE multinational database of 19030 patients. Eur J Cardiothorac Surg 1999;15:816–23.[Abstract/Free Full Text]
- Ennker J, Rosendahl U, Ennker IC, Bauer S, Florath I. Risk in elderly patients after stentless versus stented aortic valve surgery. Asian Cardiovasc Thorac Ann 2003;11:37–41[Abstract/Free Full Text]
- Westaby S, Horton M, Jin XY, Katsumata T, Ahmed O, Saito S, et al. Survival advantage of stentless aortic bioprostheses. Ann Thorac Surg 2000;70:785–91.[Abstract/Free Full Text]
- Seguin JR, Grandmougin D, Folliguet T, Warembourg H, Laborde F, Chaptal PA. Long-term results with the Sorin Pericarbon valve in the aortic position: a multicenter study. J Heart Valve Dis 1998;7:278–82.[Medline]
- Folliguet TA, Dibie A, Czitrom D, Le Bret E, Laborde F. Ten-year’s clinical experience with the Sorin Pericarbon valve. J Heart Valve Dis 2000;9:423–8.[Medline]
- Bonacchi M, Giunti G, Prifti E, Rostagno C, Bini M, Frati G, et al. Early postoperative outcome and hemodynamic performance of the sorin pericarbon stentless aortic valve. J Heart Valve Dis 2002;11:703–9.[Medline]
- Jin XY, Westaby S, Gibson DG, Pillai R, Taggart DP. Left ventricular remodelling and improvement in Freestyle stentless valve haemodynamics. Eur J Cardiothorac Surg 1997;12:63–9.[Abstract]
- Kirklin JK, Westaby S, Blackstone EH, Kirklin JW, Chenoweth DE, Pacifico AD. Complement and the damaging effects of cardiopulmonary bypass. J Thorac Cardiovasc Surg 1983;86:845–57.[Abstract]
- Kirklin JW. The science of cardiac surgery. Eur J Cardiothorac Surg 1990;4:63–71.[Medline]
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ABSTRACT
INTRODUCTION
