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Mitral valve reconstruction


Mitral valve reconstruction is desirable for patients with normal sinus rhythm because there is no need for anticoagulation, and hemodynamic performance is enhanced after surgery.

Morphology

Figure 32-1, A Myxomatous degeneration of the mitral valve, autopsy specimen. Leaflets are of variable thickness but are generally thin, with typical “hoods” or bulging. B Myxomatous degeneration of the mitral valve, magnified. Hooding of leaflet tissue is seen clearly. Chordae tendineae are thin and of normal length in this specimen, but they may be elongated or ruptured. C Myxomatous degeneration of the mitral valve, showing the leaflet position in systole. An irregular coaptation surface at multiple locations causes valve regurgitation. D Severe myxomatous degeneration of a surgically excised mitral valve specimen, showing the atrial surface. A reconstructive operation is not feasible due to the extent of disease, extensive hooding, and inadequate approximation of valve leaflets in more than one area. E Severe myxomatous degeneration of a surgically excised mitral valve, showing the ventricular surface. Note the thick and thin chordae, elongation, and rupture of chordae tendineae.

Introduction to mitral valve reconstructive techniques

Figure 32-2, A The incision is made in the left atrium just posterior to the interatrial groove on the right side. The space between the right inferior pulmonary vein and the inferior vena cava is opened to allow extension of the incision posterior to the vena cava. The decision to perform a superior incision must be weighed carefully against the risk of possible abnormal rhythm after operation. B In patients with mitral valve stenosis caused by commissural fusion and with reasonably normal subvalvular supporting structures, the commissures of the mitral valve can be divided to relieve the stenosis. The anterior leaflet of the mitral valve must be mobile and long enough to approximate the posterior leaflet. Reasonable mobility and adequate length of the posterior leaflet are also required. The atrial septum is retracted anteriorly to expose the mitral valve. A forceps is used to grasp the anterior and posterior leaflets of the mitral valve opposite the fused commissure. A No. 15 scalpel is used to accurately incise the commissure. A forceps is then used to position the commissure and, with traction, assist in teasing the commissure open accurately. Incision of the mitral valve commissure should be anatomic and as close to the mitral valve annulus as possible without exceeding the anatomic limits of the commissure. C If necessary, the chordae tendineae and papillary muscles of the mitral valve can be lengthened somewhat by incising the papillary muscle precisely between the chordae tendineae. D When redundant leaflet tissue appears to be located in a segment of the mitral valve adjacent to a commissure, the mitral valve annulus can be narrowed by placing interrupted pledget-reinforced mattress stitches through the annulus at the commissure and drawing the redundant valve tissue into the mattress stitch at the annulus. This repair is the least controllable and least symmetric and must be done judiciously. In all cases mitral valve competence should be tested by distending the ventricle with isotonic electrolyte solution using a Robinson catheter placed through the valve. This demonstrates any areas of residual leakage, which can be repaired with additional sutures.

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