MITRAL VALVE REPAIR vs REPLACEMENT : Current Recommendations and Long-Term Results - 09/09/11
Résumé |
The earliest attempts at reconstruction of the mitral valve were for relief of mitral stenosis. The first such procedures for the mitral valve were suggested in 1898 by Samways,78 who proposed notching the orifice of the stenotic mitral valve. In 1902, Brunton7 suggested that incisions in the mitral valve may relieve mitral stenosis. Cutler performed a series of operations consisting of nonanatomic leaflet incisions for mitral stenosis in 1923, but despite initial success, poor subsequent results led to his abandoning further attempts.36 Souttar performed the first clinically successful closed anatomic mitral commissurotomy by finger fracture in 1925 but because of extreme criticism did not perform any further operations.36
In 1946, Bailey, using the technique used by Souttar in 1925, split open a heavily calcified mitral valve. Because of poor results with almost immediate restenosis, Bailey in 1948 developed a technique for closed incisional commissurotomies and by 1955 was able to report a good experience with 811 cases.36 In 1947, Harken performed his initial sharp dissections of the mitral leaflets, and although the early results were poor, subsequent experience led to rapid improvement in the surgical outcomes.36
The introduction of cardiopulmonary bypass by Gibbon in 1953 led to efforts to perform mitral valve repair for mitral insufficiency using direct access through the left atrium. The implantation of the first clinically successful mitral valve prosthesis by Starr in 1960 was a major advance in the treatment of mitral regurgitation and calcific mitral stenosis.
The complications encountered then by Starr persist to some degree to the present, including transvalvular gradients, thromboembolism, hemolysis, infection, mechanical failure, and periprosthetic leaks. Bioprostheses have had significant late rates of structural deterioration in the mitral position. Burdon et al8 reported on the experience at Stanford with 793 patients who had received porcine bioprostheses. Only 45% of valves were free of structural deterioration at 15 years. Thus, interest in preservation of the native mitral valve has persisted.
The earliest techniques used for direct repair of mitral regurgitation involved attempts to correct dilation of the posterior mitral annulus by suture plication.49, 50, 51 These techniques used alone produced variable results. The single most important advance in valve repair was the description by Carpentier of a systematic approach to the classification of abnormalities of the mitral valve leaflets, annulus, and subvalvular apparatus of chordae and papillary muscles.9, 10, 21 He described three types of abnormalities: type I, normal leaflet motion; type II, prolapsed leaflet; and type III, restricted leaflet motion (Figure 1). The mitral regurgitation in type I was ascribed to either annular dilation or leaflet perforation; in type II to overriding or prolapse of one leaflet more than the other, leading to an asymmetric jet caused by ruptured chordae, elongated chordae, or a ruptured papillary muscle; in type III to commissural fusion and leaflet thickening or associated fused chordae.
A series of techniques were described for the correction of these individual anomalies that could be applied systematically with consistent results.9, 10, 21 The techniques described by Carpentier involved rigid ring annuloplasty based on the size of the anterior leaflet for repair of annular dilation, leaflet resection or patching for leaflet abnormalities, and native chordal shortening or transposition of native chordae for chordal and papillary muscle abnormalities.
Although these techniques have been applied successfully in many thousands of patients, some problems have persisted. Inability to repair the valve successfully leading to intraoperative conversion to prosthetic replacement has been reported in some series in as many as 10% to 15% of patients. When the chordae of the anterior leaflet are extensively involved and especially if the posterior leaflet is simultaneously affected, valve repair is difficult with Carpentier techniques.
Use of the original Carpentier rigid rings has been associated with systolic anterior motion (SAM) of the anterior leaflet in 15% of cases perioperatively but has been clinically significant long-term in few patients.32, 33, 38, 40, 45, 58 SAM is thought to have occurred because of excessive anterior displacement of the commissural line. Thus, in some cases, use of the size of the anterior leaflet to guide selection of the annuloplasty ring can lead to overconstriction of the posterior annulus, especially when the posterior leaflet is large. Furthermore, the rigid ring produces a symmetric posterior annuloplasty regardless of the degree of asymmetry of the posterior leaflet defect. Carpentier has developed additional surgical techniques directed at reducing the vertical dimensions of the posterior leaflet to correct the problem of SAM.21 Reports have suggested that some late failures of the Carpentier techniques have been due to further deterioration of native chordae used in the initial repair.
In 1988, the author began a systematic attempt to repair mitral valves whenever possible. To try to avoid these problems and achieve competent repair in all patients, the author reviewed the results of all techniques reported to that date and restudied the literature regarding the contribution of the dynamic behavior of the mitral annulus to mitral valve competence. As a result of these studies and earlier experiences with valve repair, the author decided to adapt the analytic approach of Carpentier for the diagnosis of the components requiring correction but to use a different combination of available surgical techniques.
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| Address reprint requests to Gerald M. Lawrie, MD, Baylor College of Medicine, 6560 Fannin, ST 1842, Houston, TX 77030 |
Vol 16 - N° 3
P. 437-448 - août 1998 Retour au numéro
Article précédent
- MANAGEMENT OF MITRAL REGURGITATION : Optimal Timing for Surgery
- Miguel A. Quiñones
- CHRONIC AORTIC REGURGITATION : Role of Medical Therapy and Optimal Timing for Surgery
- Robert O. Bonow
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