Reoperations are uncommon following a successful valvular reconstruction. When they become necessary, the circumstances of the recurrent dysfunction, the mechanisms involved, and the surgical management are important considerations since accurate knowledge of occasional failures is a condition of technical progress.
MITRAL VALVE REOPERATIONS
Perioperative Management and Approach
Reoperation for a residual or recurrent mitral stenosis or regurgitation requires specific conditions and approaches, which have been extensively described in Chapters 3 and 4 .
Mechanism of Failures and Surgical Management
Failures after mitral valve reconstruction can be classified into immediate failures (intraoperative), early failures (within first 2 years), and late failures (beyond 2 years). The causes of immediate and early failures are often technique-related whereas late failures are primarily due to the progression of the disease. In our first 15-year experience, among 72 reoperations, 28% were due to early failures and 72% to late failures.
Immediate failures resulting in residual regurgitation or stenosis or abnormal leaflet motion are revealed by intraoperative transesophageal echocardiography. The mechanisms identified by the echocardiographer are recognized by the surgeon during a second valve exploration ( Table 39-1 ).
| Functional Type | Mechanisms | Techniques * |
|---|---|---|
| Residual regurgitation | ||
| I | Abscence of ring | Ring implantation |
| I | Interscallop leakage | Indentation closure |
| I | Suture dehiscence | Closure or patching |
| II | Chordae rupture | Triangular resection or artificial chordae |
| II | Commissural leak | “Magic stitch” or free edge repositioning |
| III | Extensive anterior leaflet resection | Leaflet extension |
| Incomplete correction of prolapse | Triangular resection | |
| Residual stenosis | ||
| I-III | Improperly sized or oriented ring | New ring implantation |
| III | Restricted leaflet motion | Valve replacement |
| III | Excess posterior leaflet extension | Valve replacement |
| SAM | ||
| Excess posterior leaflet | Ovoid leaflet resection | |
| Too small ring | Larger ring | |
Most residual regurgitations or systolic anterior motion (SAM) can easily be corrected by one of the reconstructive procedures listed in Table 39-1 . By contrast, a residual rheumatic stenosis with a mean gradient ≥8 mm Hg usually requires valve replacement. Our golden rule that “no patient should leave the operating room with residual mitral regurgitation or stenosis” is based on the fact that a residual valve dysfunction is the strongest predictor of late failure and reoperation. The incidence of immediate failure, which accounted for approximately 10% of the reconstructive valve operations in our early series, has been minimized with increasing experience and rigorous respect of the following fundamental principles of valve reconstruction: preserving or restoring optimal leaflet motion, creating a large surface of coaptation, and remodeling the annulus.
An imperfect immediate result recognized by transesophageal echocardiography is usually easily repairable during a second valve exploration.
Early failure is defined as the recurrence of mitral regurgitation or stenosis within the first 2 years following an initially satisfactory result. Among the numerous causes of early failure ( Table 39-2 ), annular dilatation is the most frequent in patients without ring annuloplasty. A ring had not been implanted either because the annulus was minimally dilated or because of the reluctancy to use a ring in children. In our experience from 1975 to 1997, among 120 patients who underwent a mitral valve reconstruction without an annuloplasty ring, 20% required reoperation at a mean interval of 2 years. The linearized rate of reoperation of 3.3% per patient year (pt/yr) contrasts with the 1% per pt/yr reoperation rate found in another series of patients who systematically had a remodeling annuloplasty.
| Functional Type | Mechanisms | Techniques * |
|---|---|---|
| Recurrent regurgitation | ||
| I | Abscence of ring | Ring implantation |
| I | Ring dehiscence | Ring refixation |
| Suture dehiscence | Primary closure or patching | |
| II | Chordae rupture | Triangular resection or artificial chordae |
| II | Chordae elongation | Triangular resection or concertino technique |
| II | Commissural leak | Edge repositioning or artificial chordae |
| Illb | Restricted leaflet motion | Leaflet extension or valve replacement |
| Valve stenosis | ||
| Illa | Fibrous retraction | Valve replacement |
| Endocarditis | ||
| I-II | Excision and patching or valve replacement | |
An early failure can often be corrected during a reoperation ( Table 39-2 ). Whenever a ring implanted during the first operation appears well-positioned and inserted, it may be possible to leave it in place and to choose a technique at the leaflet level, for example, a limited triangular resection or an edge repositioning by chordae transfer ( Fig. 39-1, a ).
Whenever the ring is small or extensive access to the subvalvular level is necessary to proceed to a papillary muscle sliding plasty or the placement of artificial chordae, the ring can be partially detached and mobilized in the area of prolapse (b) . The upward traction on the detached segment combined with lateral traction of the corresponding segment of the annulus provides access to the ventricular cavity sufficient enough to proceed to the selected maneuver ( Fig. 39-1 ).
The most common cause of early failure of a valve repair is the absence of ring annuloplasty.
Late failures , beyond 2 years after the operation, are often related to the progression of the disease. The underlying mechanism is a new prolapse in patients with degenerative valve disease, progression of the fibrotic process in patients with rheumatic disease, or continuing ventricular remodeling in dilated or ischemic cardiomyopathies ( Table 39-3 ). In degenerative valvular diseases with excess tissue and adequate leaflet pliability, the surgeon can often re-repair the valve. Late failure in patients with type III dysfunction usually requires valve replacement.
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