Long-Term Assessment of Mitral Valve Reconstruction With Resection of the Leaflets: Triangular and Quadrangular Resection

Long-Term Assessment of Mitral Valve Reconstruction With Resection of the Leaflets: Triangular and Quadrangular Resection Yoshimasa Sakamoto, MD, Kazuhiro Hashimoto, MD, Hiroshi Okuyama, MD, Shinichi Ishii, MD, Makoto Hanai, MD, Takahiro Inoue, MD, Gen Shinohara, MD, Kiyozo Morita, MD, and Hiromi Kurosawa, MD Department of Cardiovascular Surgery, The Jikei University School of Medicine, and Department of Cardiovascular Surgery, The Heart Institute of Japan, Tokyo Women s Medical University, Tokyo, Japan Background. The procedure of quadrangular resection and suture for prolapsed posterior leaflet of the mitral valve is a reliable and reproducible method that achieves excellent long-term results. However, triangular resection and suture of a prolapsed anterior leaflet is not widely supported and different techniques have been advocated. The aim of this study was to review our experience of mitral valve repair in which resection of the anterior and/or posterior leaflets was performed. Methods. Between October 1991 and September 2003, 105 patients with mitral regurgitation underwent mitral valve reconstruction with leaflet resection, including 55 patients with quadrangular resection of the posterior leaflet (P), 32 patients with triangular resection of the anterior leaflet (A), and 18 patients with resection of both leaflets (A P). Results. The mean follow-up period was 63.6 (1 to 139) months. Reoperation was required in 2 patients, each Mitral valve repair for mitral insufficiency is widely performed as an alternative to valve replacement. Compared with valve replacement, repair has a lower risk of thromboembolism, hemorrhage, and infectious endocarditis [1 10]. As another advantage, anticoagulant therapy can be tapered and ceased by 3 to 6 months after mitral valve repair. Moreover, postoperative left ventricular function is better after reconstruction than after valve replacement because the mitral valve apparatus is preserved [11, 12]. We have performed valve reconstruction surgery according to Carpentier s procedures [13], with different techniques being used for each pathological abnormality. Although most of these techniques have been widely accepted, triangular resection of a prolapsed anterior leaflet seems to be rarely performed and is controversial because of the relatively high risk of recurrent regurgitation [5]. However, we have considerable experience with the technique of triangular resection for prolapsed anterior leaflets as well as quadrangular resection for the posterior leaflet. The aim of this retrospective after resection of the anterior or posterior leaflet. The freedom from reoperation rates at 10 years in 93% 5% of patients after triangular resection of the anterior leaflet, 96% 3% after quadrangular resection of the posterior leaflet, and 100% after resection of both leaflets. There were no significant differences of survival or risk of reoperation among these three groups. The postoperative mitral valve area was significantly smaller than the preoperative area in all three groups, but remained large enough (A: 2.84 1.07; P: 2.6 0.87; A P: 3.09 1.20 cm 2 ) for adequate valve function. Conclusions. Triangular resection of a prolapsed anterior mitral leaflet is a reliable, reproducible, and durable procedure, like quadrangular resection of a prolapsed posterior leaflet. (Ann Thorac Surg 2005;79:475 9) 2005 by The Society of Thoracic Surgeons study was to evaluate the long-term outcome of anterior leaflet resection and to compare it with posterior leaflet resection. Patients and Methods Patients From October 1991 to September 2003, 128 patients with mitral valve incompetence underwent valve reconstruction surgery. Among them, one hundred and five patients had resection of the anterior leaflet, posterior leaflet, or both leaflets. The characteristics of the patients before operation are shown in Table 1. Patients with mitral stenosis and congenital mitral valve disease were excluded from this study. Operative Technique We basically adopted the techniques described in Carpentier s report [13]. The operative techniques are summarized in Table 2. Our usual method of repairing a Accepted for publication July 19, 2004. Address reprint requests to Dr Sakamoto, Department of Cardiovascular Surgery, The Jikei University School of Medicine, 3-25-8 Nishishinbashi, Minato-ku, Tokyo 105-8461, Japan; e-mail: yysakamoto@aol.com. This article has been selected for the open discussion forum on the CTSNet Web site: http://www.ctsnet.org.discuss 2005 by The Society of Thoracic Surgeons 0003-4975/05/$30.00 Published by Elsevier Inc doi:10.1016/j.athoracsur.2004.07.046

476 SAKAMOTO ET AL Ann Thorac Surg MITRAL VALVE REPAIR WITH RESECTION OF LEAFLETS 2005;79:475 9 Table 1. Patient Characteristics No. (M/F) 105 (74/31) Age (range) 52.4 14.5 (18 78) Follow-up duration (years) 5.3 3.5 (0.8 11.6) Etiology degenerative 91 (86.7%) ischemic 4 (3.8%) endocarditis 8 (7.6%) traumatic 1 (0.9%) rheumatic 1 (0.9%) NYHA class I 12 II 49 III 30 IV 14 EF (%) 68 11 Degree of MR none 0 mild 0 moderate 23 severe 82 Cardiac rhythm Sinus rhythm 79 (75%), Atrial fibrillation 26 (25%) Carpentier s classification type I 8 (7.6%) II 95 (90.5%) III 2 (1.9%) EF ejection fraction; F female; M male; MR mitral regurgitation; NYHA New York Heart Association. prolapsed anterior leaflet was as follows: before excision of the prolapsing segment, pilot sutures were positioned in the healthy areas on each side and the improvement of prolapse was assessed. Then a small segment of the leaflet was excised, which was no greater than 1.5 cm in width and was limited in depth so that it did not exceed the middle of the leaflet. The procedures utilized for treatment of elongated or ruptured chordae tendinae were shortening [14] by wrapping and shortening chordoplasty (WSCP: n 28), chordal transfer (n 4), and chordal replacement with a polytetrafluoroethylene graft (Gore-Tex CV-4, WL Gore & Assoc, Flagstaff, AZ) (n 5). Table 2. Surgical Procedures Procedures No. (%) Posterior leaflet resection 55 (52) Anterior leaflet resection 32 (31) Anterior and posterior leaflet resection 18 (17) Chordae shortening 28 (27) Chordae transfer 4 (4) Chordae replacement with PTFE 5 (5) Cleft closure 2 (2) Imbrications suture 2 (2) Valve debridement 2 (2) Compression suture 2 (2) PTFE polytetrafluoroethylene. Table 3. Associated Procedures Procedure No. of Patients Tricuspid annuloplasty 14 Coronary artery bypass 9 Aortic valve replacement 2 Closure of atrial septal defect 4 Maze 6 In WSCP, the elongated chorda closest to the resected portion of the anterior leaflet was wrapped and shortened at the time of approximation of the cut surfaces of the leaflet. Ring annuloplasty was performed in 104 patients. A Carpentier-Edwards rigid ring was used in 96 patients and a Physio-ring (Baxter Healthcare Corp, Edwards Division, Santa Ana, CA) was used in 8 patients. Concomitant procedures were performed in 26 patients (Table 3). Valve competence was evaluated by injection of a bolus of saline into the left ventricle during cardiac arrest and by transesophageal echocardiography during or after cardiopulmonary bypass before the operation was finished. All patients received anticoagulation with warfarin and an antiplatelet agent for 3 months postoperatively, and then warfarin was discontinued, except in the patients with atrial fibrillation. Echocardiography All patients underwent transthoracic echocardiography before and one month after the operation to evaluate mitral valve competence, mitral valve area (MVA), and left ventricular function. Then echocardiography was done twice a year in most of the patients. Doppler echocardiography was performed in the apical and parasternal long-axis views. Mitral regurgitation was estimated from the ratio of the regurgitant Color Doppler area in the left atrium and its severity was quantified into four grades (none [0], mild [1], moderate [2], or severe [3]) by the echocardiographers. Statistical Analysis All values are expressed as the mean standard deviation. Survival and freedom from reoperation were estimated by the Kaplan-Meier method. The paired t test was used to compare data before and after surgery. Comparison among the groups with anterior leaflet, posterior leaflet, and bileaflet resection was done by one-factor analysis of variance. Differences among the groups with regard to survival and freedom from reoperation were evaluated by the log-rank test, and p less than 0.05 was considered significant. Results Mortality Among the 105 patients, there were 4 hospital deaths for an operative mortality rate of 3.8%. The 101 surviving patients were in New York Heart Association class I (97 patients) and class II (4 patients) at the end of the follow-up period. The overall actuarial survival rate at 10 years was 95 2% (). Comparison of the three groups

Ann Thorac Surg SAKAMOTO ET AL 2005;79:475 9 MITRAL VALVE REPAIR WITH RESECTION OF LEAFLETS 477 Fig 1. Actuarial survival curve for overall mortality (hospital mortality is included). (anterior, posterior, and bileaflet resection) showed no significant differences in survival after repair (Fig 2). Reoperation Figure 3 shows the rate of freedom from reoperation in all patients. The overall rate of freedom from reoperation at 10 years was 96 2% and the three different leaflet resection groups showed no significant differences in freedom from reoperation (Fig 4). Reoperation after mitral valve repair was only necessary in 4 (3.8%) patients. All 4 had degenerative valve disease. The initial procedure included triangular resection of a prolapsed anterior leaflet in 2 patients and quadrangular resection of a prolapsed posterior leaflet in 2 patients. Reoperation was performed within one year in 3 Fig 3. Rate of freedom from reoperation. out of 4 patients. One patient underwent quadrangular resection of the posterior leaflet and chordal reconstruction with artificial grafts for the prolapsed anterior leaflets, but mitral regurgitation was progressive due to disruption of the chordal graft at the insertion into the leaflet. Sutures closing the resected leaflets were partially disrupted in the other 3 patients and this led to mitral regurgitation. All patients survived reoperation with mitral valve replacement. Echocardiographic Evaluation Complete preoperative and postoperative echocardiographic data were obtained in 90 patients and the mean observation period after surgery was 60.8 months. The data Fig 2. Actuarial survival curves of patients with posterior leaflet resection, anterior leaflet resection, and bileaflet resection. - posterior (55); --- anterior (32); both (18). Fig 4. Rate of freedom from reoperation in patients having posterior leaflet resection, anterior leaflet resection, and bileaflet resection. - posterior (55); --- anterior (32); both (18).

478 SAKAMOTO ET AL Ann Thorac Surg MITRAL VALVE REPAIR WITH RESECTION OF LEAFLETS 2005;79:475 9 Table 4. Echocardiographic Findings Posterior Leaflet Resection (n 45) Anterior Leaflet Resection (n 30) Anterior and Posterior Leaflets Resection (n 15) Before After p Value Before After p Value Before After p Value LVEDVI (ml) 126.2 36.1 70.8 27.2 0.01 116.2 47.8 65.3 28.6 0.05 116.0 47.0 68.5 24.8 0.01 LVESVI (ml) 39.5 21.5 32.0 33.7 NS 36.9 16.2 28.0 16.0 0.01 39.8 23.6 27.1 15.2 0.01 EF (%) 69.4 11.2 63.4 14.1 0.01 69.6 9.6 52.3 13.5 0.01 65.0 10.7 63.1 13.0 NS PF (m/sec) 1.35 0.35 1.18 0.31 0.05 1.27 0.33 1.36 0.38 NS 1.45 0.42 1.11 0.35 NS PG (mm Hg) 4.5 3.9 3.8 2.4 NS 4.7 3.8 5.4 4.3 NS 5.3 5.0 3.9 3.0 NS PHT (msec) 67.6 19.3 93.8 27.0 0.01 67.5 20.7 92.6 39.2 0.01 66.1 18.3 82.4 27.8 NS MVA (cm 2 ) 3.60 0.92 2.60 0.87 0.01 3.48 0.95 2.84 1.07 0.05 3.38 0.81 3.09 1.20 NS EF ejection fraction; LVEDVI left ventricular end diastolic volume index; LVESVI left ventricular end systolic volume index; MVA mitral valve area; NS not significant; PF peak flow; PG pressure gradient; PHT pressure half time. are summarized in Table 4. The left ventricular enddiastolic and end-systolic volumes showed a significant decrease after mitral valve repair. Postoperative MVA was significantly smaller than the preoperative value in all three resection groups (anterior, posterior, and bileaflet), but the postoperative MVA was always adequate for valve function. When an additional 6 patients, in whom only information regurgitation was obtained by follow-up, were included, eighty-two (85%) patients had no mitral regurgitation at the end of follow-up, while it was mild in 12 patients and moderate in 2 patients (Fig 5). Comment Mitral valve reconstruction has become increasingly popular and various repair techniques have been used in patients with mitral regurgitation. Since 1991, we have adopted the techniques that Carpentier described in 1983 [13]. In this study, we examined the long-term outcome of mitral repair more than 12 years in our hands. We were particularly interested in whether there was a difference of results according to whether the posterior leaflet, anterior leaflet, or both leaflets underwent resection. Fig 5. Mitral valve regurgitation: preoperative and postoperative pulsed Doppler echocardiography. Quadrangular resection of a prolapsed posterior leaflet and annular plication is seen as a reliable and reproducible procedure with excellent long-term results [15, 16]. On the other hand, triangular resection of a prolapsed anterior leaflet initially achieved disappointing results. Carpentier recommended that resection should be limited to no more than one tenth of the area of the anterior leaflet when it was necessary. Because the results are less predictable, resection to treat anterior leaflet prolapse is still a controversial technique. Other methods, such as chordal translocation, the flip-over technique, and artificial chordal implantation, are options that are used in this case. Braunberger and colleagues [8] reported that the freedom from reoperation rates at 10 years in Carpentier type II patients with procedures involving the posterior leaflet, anterior leaflet, and both leaflets were 99%, 86%, and 88%, respectively. In our experience, the freedom from reoperation rate at 10 years was 96% for patients with resection of the posterior leaflet, 94% for patients with resection of the anterior leaflet, and 100% for patients with bileaflet resection. There was no significant difference in the risk of reoperation, regardless of the site of prolapse. Grossi and colleagues [16] aggressively performed triangular resection for repair of prolapsed anterior leaflets, and it was done in 28% of their patients (44 of 156 patients); reoperation was necessary in 4.5% (2 of 44 patients). Recent reports about triangular resection of the anterior leaflet have been encouraging and suggest that it can be performed safely [17, 18]. Of the 50 patients treated with anterior leaflet resection in our series, reoperation was only required in 2 (2%) patients for a rate of 0.34% patient years. Also, reoperation only occurred in our early cases and the cause was dehiscence of the leaflet due to excessive resection. At present, our general concept of triangular resection seems to be similar to basic guidelines by Spencer and colleagues [17]; ie, removal of a small triangular portion (no greater than 1.5 cm) of the prolapsing anterior leaflet so that the cut surfaces of the leaflet can be anastomosed without tension. The mitral valve area and coaptation zone should be conserved after resection of the leaflet. It is important to test the result before excision of the prolapsing tissue and provisional stitches are very useful for deciding which part of the leaflet or how much of it should be excised. Another repeat operation early in the series was due to disruption of the anterior leaflet at the site where an

Ann Thorac Surg SAKAMOTO ET AL 2005;79:475 9 MITRAL VALVE REPAIR WITH RESECTION OF LEAFLETS 479 artificial chorda (CV-4 Gore-Tex) was anchored. Since then, we have avoided reconstruction with artificial chordae as far as possible. As an alternative, utilizing the elongated chordae or vicinal chordae has become our major technique. The elongated chorda located near the resected part of the anterior leaflet is wrapped and shortened at the time of approximation of the cut edges of the leaflet (WSCP). We believe that conservation of native chordae can contribute to reinforce the approximated leaflets and prevent suture disruption. We also regard the chordal shortening technique as one of supportive techniques for success. The flip-over technique [19] was also utilized if there were no usable chordae attached to the anterior leaflet. In recent years, we have started using artificial chordae in some cases because good long-term results and technical improvement have been reported [20 22]. The technique of triangular resection employed in this series has been performed for an isolated segmental prolapse. Indeed, typical Barlow s valves have rarely been seen in Japan. Fasol and Joubert-Hübner [18] addressed that patients with extensive myxomatous and excessive leaflet tissue are prone to developing abnormal systolic anterior motion and left ventricular outflow obstruction after mitral repair without resection of excessive leaflet. If huge leaflet prolapse like the Barlow s valve is present, it should be excised adequately and implanted with a number of artificial chordae. Resection techniques mixed with implantation of artificial chordae may contribute to good results. In addition to the importance of the correct resection technique, postoperative valve function is another major concern. The MVA may decrease markedly after resection of the anterior leaflet, although this rarely occurs after resection of the posterior leaflet alone. However, our observations using postoperative echocardiography showed that the MVA was 2.84 1.07 cm 2 in the anterior leaflet resection group, which was within the lower normal range. The result was the same in patients with resection of both leaflets. There was no left ventricular inflow obstruction and the MVA was large enough for adequate valve function. This result supports the appropriateness of performing triangular resection of a prolapsing anterior leaflet. In conclusion, there were no significant differences of freedom from reoperation and survival rates at 10 years among patients undergoing anterior, posterior, or bileaflet resection. The need for reoperation after mitral valve repair has decreased significantly in recent years. Triangular resection of a prolapsed anterior leaflet was shown to be a reliable, reproducible, and durable procedure by our long-term follow-up study, as was quadrangular resection of a prolapsed posterior leaflet. References 1. 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