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a Department of Thoracic and Cardiovascular Surgery, Seoul National University Borame Medical Center, Seoul, South Korea
b Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul, South Korea
Accepted for publication April 2, 2009.
* Address correspondence to Dr Ahn, Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, 28, Yeongeon-dong, Jongno-gu, Seoul, 110-744, Korea (Email: ahnhyuk{at}snu.ac.kr).
Presented at the Poster Session of the Forty-fifth Annual Meeting of The Society of Thoracic Surgeons, San Francisco, CA, Jan 26–28, 2009.
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Abstract |
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 Top Abstract IntroductionPatients and MethodsResultsCommentReferences |
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Methods: Between March 1995 and August 2004, 41 consecutive patients were included. The mean age was 32.2 ± 13.9 years. The causes of AR were rheumatic in 31 patients (75.5%), degenerative in 2 patients (4.9%), bicuspid aortic valve in 4 patients (9.8%), infective endocarditis in 1 patient (2.4%), and congenital in 3 patients (7.3%). Leaflet extensions were performed in three leaflets for 32 patients, two leaflets for 3 patients, and only one leaflet for 6 patients. The mean follow-up duration was 92.9 ± 48.4 months.
Results: There were no early deaths and 2 late deaths. One patient died of cancer and the other patient died of infective endocarditis. The cardiac-related mortality was 2.4% (1 of 41 patients). During a mean follow-up of 7 years, severe AR was detected in 1 patient and moderate AR in 6 patients (17.0%; 7 of 41 patients). The causes of recurrent AR were infective endocarditis in 3 patients, disease progression in 3 patients, and Behçet's diseases in 1 patient. We performed 6 reoperations (14.6%), 3 in patients owing to infective endocarditis, 2 in patients owing to disease progression, and 1 in a patient owing to the suture dehiscence associated with Behçet's disease. The cumulative survival was 92.6% at 13 years. Freedom from recurrent AR was 97.5% at 5 years, 81.7% at 10 years, and 68.1% at 13 years.
Conclusions: The long-term durability of the leaflet extension technique was acceptable. The reoperations increased with time, but pericardial leaflet dysfunction was not the cause.
The interest in aortic valve repair has been growing for more than a decade. The ideal surgical technique for aortic valve repair for aortic regurgitation (AR) depends on the etiology, echocardiographic findings, valve morphology, patient's general condition, and other factors. With increased experience, various pathologic mechanisms have been elucidated and corrected surgically. Aortic regurgitation caused by aortic root dilatation with normal leaflets can be corrected by replacement of the proximal aorta with an appropriate size graft. In such cases, good results have been reported [1, 2]. However, in more complex cases, valve repair remains a difficult procedure. More recently, as awareness of the limitations of artificial valves has increased, attention has been focused again on valve repair in severe cases.
Among the various repair techniques for AR, the leaflet extension technique has been used in cases of severe cusp retraction that cannot be corrected by cusp slicing, free edge unrolling, or other valve repair procedures. The ideal material for leaflet extension remains controversial. The results of leaflet extension with several materials (fascia lata, dura mater, and bovine pericardium) have not been acceptable according to reports in the past [3–5]. Fresh autologous pericardium is easy to obtain, but is limited by short-term durability [6]. Treatment of autologous pericardium with glutaraldehyde seems to improve the durability of repair, but for how long remains unknown [7]. Indeed, promising early and mid-term results using glutaraldehyde-fixed autologous pericardium for leaflet extension are emerging [8, 9]. We have performed the leaflet extension technique with glutaraldehyde-fixed autologous pericardium in aortic valve repair since 1995. The mid-term results of our technique were acceptable, as we previously reported [10]. The aim of this study was to evaluate the effectiveness and durability of the leaflet extension technique with glutaraldehyde-fixed autologous pericardium and the long-term clinical results.
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Patients and Methods |
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Operative Procedures
The basic surgical procedures of aortic valve repair have been previously described (Fig 1) [10]. After transverse aortotomy 1.5 cm above the ostium of the right coronary artery, all three aortic valve cusps were examined thoroughly. The exclusion criteria were severe calcification and severe leaflet thickening, which might reduce leaflet mobility. The autologous pericardium was fixed in 0.625% glutaraldehyde solution for 15 minutes and rinsed in three successive normal saline solutions. After measurement of the cusp-free margin with a compass, the pericardium was designed at a height of 8 to 10 mm, and the length was the same as the free margin of each cusp. Implantation started at the commissures between the right and left cusps using 5-0 polypropylene continuous suture. The single running suture was completed at the commissure between the right and noncoronary cusps and threaded into the aortic wall, and the ligature was made. The commissures were extended by approximating every two adjacent pericardial strips with several interrupted 5-0 polypropylene stitches placed through the aortic wall and tied over it (ie, formation of a neocommissure). We placed the mesothelial surfaces of the pericardium toward the left ventricle. We checked the amount of the left ventricular vent after release of the aortic cross-clamp and during weaning from cardiopulmonary bypass. Leaflet extensions in three leaflets were performed in 32 patients (78%), two leaflets in 3 patients (7.3%), and a single leaflet in 6 patients (14.6%). In the cases involving a single leaflet extension, the shape of the pericardium was crescent rather than rectangular. The additional procedures on the aortic valve were commissurotomy to improve leaflet motions in 9 patients (22.0%), leaflet slicing in 2 patients (4.9%), and raphe release for bicuspid aortic valves in 4 patients (9.8%). The concomitant procedures included mitral valve repairs in 9 patients (22%), pulmonary vein isolation in 1 patient, and right ventricular outflow tract widening in 1 patient (Table 1). No patient left the operating room with an AR grade of II or more. The mean cardiopulmonary bypass and myocardial ischemic times were 143.7 ± 43.2 minutes and 114.6 ± 39.3 minutes, respectively. No patient required a second period of aortic occlusion to correct residual AR.
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Statistical Analysis
Statistical analysis was performed with the SPSS software package (version 11.0; SPSS, Inc, Chicago, IL). Postoperative results were classified as early (before 30 days) or late (after 30 days). Differences between continuous variables were tested using the paired Student's t test. The significances of differences of categorical variables were assessed using the 
2 test or Fisher's exact test. Cox proportional hazard regression analysis was used to assess the risk factors for recurrent AR. Kaplan-Meier methods were used to analyze the probability for survival and freedom from events. All results were expressed as the mean ± standard deviation or as proportions, and a probability value of less than 0.05 was considered as statistically significant.
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Results |
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Late complications were infective endocarditis in 3 patients (7.3%), tricuspid regurgitation in 2 patients (4.9%), thromboembolism in 1 patient (2.4%), and a wound problem in 1 patient (2.4%). The New York Heart Association functional class was much improved at last follow-up (92.9 ± 48.4 months; 2.3 versus 1.1; p = 0.001).
Transthoracic echocardiography was performed during the follow-up period in 38 patients (92.7%; a mean interval of 81.6 ± 43.5 months). The mean left ventricular end-systolic dimension and left ventricular end-diastolic dimension were 37.2 ± 7.2 mm and 55.0 ± 7.5 mm, respectively. The mean left ventricular ejection fraction was restored to 0.550 ± 0.075. The mean AR grade was 1.5 ± 1.1. Residual AR greater than grade II was detected in 2 patients during the mid-term follow-up period (a mean interval of 31.8 ± 21.8 months). Aortic regurgitation progression to grade III or IV was noted at the last follow-up echocardiography in 7 patients (Table 2).
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We performed 6 reoperations (14.6%; 6 of 41 patients) for recurrent AR with a mean of 55.3 ± 48.3 months (range, 4.0 to 129.2 months); 3 patients because of infective endocarditis, 2 patients because of disease progression, and 1 patient because of the suture dehiscence associated with Behçet's disease. The patient with recurrent moderate AR who did not undergo reoperation has been followed with cardiac medication because he was asymptomatic. Among 3 patients with infective endocarditis, the first patient died of sepsis after surgery, as previously described. The second patient had fungal endocarditis attributable to Trichosporon beigelii 7 months after surgery and severe AR occurred. We identified the previous suture line for leaflet extension and the autologous pericardial leaflet was intact. Leaflet perforation and vegetations were found on the annulus and native valve leaflets. We performed aortic valve replacement, but 4 months later endocarditis recurred, to be subsequently cured by medical treatment. The third patient underwent triple leaflet extension as a result of infective endocarditis. During follow-up, infective endocarditis occurred with a different pathogen. We also noted the pericardial leaflets were normal during reoperation. Two patients who underwent aortic valve replacement as a result of disease progression of native aortic valve structure had rheumatic valve disease. Of these 2 patients, one required mitral valve replacement and tricuspid annuloplasty. The intraoperative findings showed no abnormalities in the pericardial leaflets in both patients. The last patient was suspected to have features of Behçet's disease. Leaflet extension was performed in one retracted cusp. Three months later, the patient experienced sudden dyspnea. The echocardiography revealed grade IV regurgitation. A Ross procedure was performed, and partial dehiscence was noted in the leaflet extension suture line. There were no calcifications, thickening, or degenerative changes in the pericardial leaflets.
According to univariate analysis, the significant negative predictors of recurrence of AR were age and number of extended cusps. Cox hazard studies identified that all risk factors were insignificant for AR recurrence (Table 3). The actuarial rate of freedom from AR recurrence was 97.5% at 5 years, 81.7% at 10 years, and 68.1% at 13 years. The actuarial rate of freedom from reoperation was 94.9% at 5 years and 86.2% at 10 years (Fig 3).
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Comment |
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Aortic valve repair has known advantages over valve replacement in terms of low incidence of thromboembolism and infective endocarditis, as well as hemodynamic benefits. For these reasons, preserving the aortic valve has promoted an increase in interest in aortic valve repair techniques. Among various techniques of aortic valve repair, leaflet extension techniques have been used to extend or replace deficient cusps for enhancing the coaptation area. Lillehei and associates [12] first introduced single cusp enlargement with an Ivalon sponge. Since 1960, several materials, such as polytetrafluoroethylene (Teflon), fascia lata, bovine pericardium, and autologous pericardium, have been used for cusp extension or replacement. Most materials, except autologous pericardium, are limited to insertion because of unfavorable short-term durability [3–5]. The early failures were caused by patch dehiscence and calcification. The reasons for calcification remain unclear, with mechanical stress, biochemical factors, and immunologic factors having been suggested. Calcification is known to develop more frequently in xenograft patches; thus we decided to use autologous pericardium. Fresh autologous pericardium was associated with poor results owing to early thickening and retraction, and Kalangos and colleagues [13] proved that leaflet extension with fresh autologous pericardium in pediatric patients with rheumatic AR had serious problems associated with calcification and primary tissue failure. Duran and colleagues [14] described the possibility of aortic valve repair with autologous pericardium and demonstrated improved performance compared with bovine pericardium. In this technique, intraoperative glutaraldehyde treatment was adopted. In theory, glutaraldehyde treatment provides the pericardium with more resistance to retraction and degeneration and maintains the intrinsic tissue pliability [7]. Chauvaud and associates [15] demonstrated that a 15-minute fixation in 0.625% glutaraldehyde solution reduced the immunologic reaction caused by the stabilizing effect induced by the cross-linkage of collagen materials. We adopted this method in hope of long-term durability.
With respect to the technical aspects of leaflet extension, Batista and coworkers [16] used one patch folded lengthwise in thirds and tailored according to the shape of the patient's native valve leaflets, whereas Duran and colleagues [14] used a mold for tailoring the pericardium. They excised diseased cusps and sutured the pericardium to the resected margins. We thought they tried to standardize their technique by remaining almost equal in size to the native pericardium. In the present study, the leaflet tissue was not removed. In case the lengths and heights of the cusp-free margins were not equal, we tailored the upper border of the pericardial patch after careful coaptation of the three patches. Although it was somewhat difficult to adjust the size of the pericardial patches, we thought this technique had the merits of leaving native tissue attached to the annulus, thus the natural hinge mechanism was considered to be preserved and coaptation of the three cusps improved.
There are a few reports in the literature describing the long-term results of the leaflet extension technique for rheumatic disease. Grinda and colleagues [8] investigated the leaflet extension technique on 89 patients who underwent triple leaflet extension with autologous pericardium. They reported an actuarial survival at 5 years of 96%, and 92% were free from reoperation. Most patients of this study had rheumatic disease. Similarly, Bozbuga and colleagues [9] reported on 46 patients, who were mostly adults with rheumatic valve disease undergoing leaflet extension with autologous pericardium. According to their report, actuarial survival at 8.6 years was 98%, but the reoperation rate was 20% (4.3% per patient-year). They stressed the cause of reoperation was progression of rheumatic disease with dense fibrosis. We also reported the mid-term results of leaflet extension in 2002 [10]. The cumulative survival at 5 years was 94.1%, and freedom from reoperation at 1 year and after was 93.8%. The longest available results for 16 years were recently reported for 92 patients (mean age, 30 years) with mainly rheumatic disease [17]. The results between the bovine pericardium and autologous pericardium groups were compared. The overall survival rate was 85%, and freedom from reoperation was 68% at 10 years and 47% at 16 years. The long-term durability was not different between the groups, but they preferred autologous pericardium because of the low cost and easy availability. Several groups have recently explored the results of leaflet extensions in patients with congenital aortic valve disease. Odim and colleagues [18] described the use of autologous pericardial leaflet extension in the congenital group and reported a 92% freedom from valve-related reoperation at 2 years. They asserted that leaflet extension with autologous pericardium was a good alternative option for congenital aortic valve disease. More recently, De La Zerda and colleagues [19] found that aortic valve-sparing repair with autologous pericardial leaflet extension had a greater early reoperation rate in congenital versus acquired valve disease.
In the present study, freedom from recurrent AR at 5 years was 97.5%; however, 68.1% of patients were free from recurrent AR at 13 years. Aortic regurgitation progression was inevitable with time if the underlying disease was progressive. Seven patients had grade III or more AR, and 6 patients required reoperation for aortic valve replacement during the follow-up period (the longest was 13.3 years). Among the causes of recurrent AR, pericardial leaflet dysfunction or degeneration was not included, and this finding was not different from those of other reports [9]. In all cases of reoperations, intraoperative findings demonstrated autologous pericardial leaflets showed the same pliability of the index operations without any focal calcifications. Infective endocarditis occurred in 3 patients (7.3%; 3 of 41 patients). All the patients with infective endocarditis in our study did not have predisposing factors, such as dental treatment and history of surgeries. This was a relatively high incidence in comparison with other valve prosthetic endocarditis as reported by Senning and coworkers [3]. They reported that infective endocarditis occurred in 14% of the patients who underwent single and triple cusp extension and total valve replacement with fresh autologous fascia lata. Similar findings exist in the report of Al Halees and colleagues [17], in which the incidence of infective endocarditis in the patients with leaflet extension with glutaraldehyde autologous pericardium was 10.8% (7 of 65 patients). Whether this potential problem is inherent in the use of autologous tissue is unknown. More studies are needed to elucidate the relationship between infective endocarditis and autologous tissue. Two patients who underwent reoperations because of disease progression, such as native leaflet thickening and commissural fusion, had rheumatic heart disease. Intervals between original repair and reoperation were 60 and 130 months, respectively.
The accurate assessment of the adequacy of aortic valve repair with leaflet extension is very important. This assessment is difficult in aortotomy status. We used the measurement of the regurgitant volume obtained through the left ventricular vent and intraoperative color Doppler echocardiography to evaluate postoperative aortic valve function. Transesophageal echocardiography is useful to assess the adequacy of valve repair and similar to reports of other surgeons who are interested in valve repair [20]. We have routinely performed transesophageal echocardiography after the induction of anesthesia and checked the AR both during and after cardiopulmonary bypass weaning since 2000.
According to our report, the age and number of extended leaflets were significant as negative risk factors for recurrent AR, and preoperative AR grade and New York Heart Association functional class were not significant. This result is different from that of another analysis [9] in which severe AR and New York Heart Association functional class were negative risk factors for reoperation and the number of extended cusps and age were insignificant. However, these results were derived by univariate analysis, not by multivariate analysis with a small number of patients. The statistical significance should not be overestimated for this reason. The preoperative condition of patients and surgical techniques requiring more dexterity might influence the long-term durability of leaflet extension. More studies with larger numbers should be performed to reveal risk factors for recurrent AR and reoperation after aortic valve repair with leaflet extension.
Because of the obvious limitation of this small series of a single center, more experience with a larger number of patients and a true long-term follow-up are required to provide more reliable information.
In conclusion, we present our long-term experience of the leaflet extension technique using glutaraldehyde-fixed autologous pericardium in patients with various causes (mainly rheumatic) of AR. We could conclude that the long-term results were acceptable, and the pericardial leaflets did not cause AR recurrence. We suggest that this technique should be considered, especially in young patients of childbearing age.
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  S. Chauvaud Invited commentary. Ann. Thorac. Surg., July 1, 2009; 88(1): 89 - 89. [Full Text] [PDF]
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