A commissural leaflet prolapse is a valve dysfunction typically seen in bacterial endocarditis or in degenerative valvular diseases. The cause of the prolapse is either chordae rupture in bacterial endocarditis or chordae elongation in degenerative diseases. The extent of the prolapse can be defined as limited or extensive. A limited prolapse involves the commissural leaflet and measures 5 mm or less of the leaflet margin ( Fig. 12-1 a ). An extensive commissural prolapse involves the commissural leaflet and either one or both paracommissural areas ( b ). The technique of reconstruction depends upon the extent of the prolapse and the lesions causing the prolapse ( Table 12-1 ). Whatever the technique used, the aim is not only to correct the regurgitation but also to restore optimal function of the commissure; to avoid turbulence, fibrous proliferation, or calcification; and to achieve long-term function.
| Limited Prolapse | Extensive Prolapse | ||
|---|---|---|---|
| Due to Chordae Rupture | Due to Chordae Elongation | ||
| Techniques | Triangular leaflet resection | Quadrangular leaflet resection | Papillary muscle sliding |
| Alternative Technique | Chordae transposition | Chordae replacement | Papillary muscle shortening |
LIMITED PROLAPSE
The commissure is an important component of the mitral valve, the reconstruction of which is a condition for normal long-term function.
A limited prolapse involving ≤5 mm of the commissural edge is treated by triangular leaflet plication ( Fig. 12-2 ) (i.e., McGoon’s plication) or preferably by triangular resection (inset) . Resection is preferred because it removes a potential cause of recurrent infection: leaflet retraction and fibrosis. A plication can be used in case of small prolapse and noninfected tissue. In both techniques, two 4-0 sutures are placed at the limits of the prolapsed area. Gentle traction allows visualization of the triangle of tissue to be resected or plicated (a) . The height of the triangle should be slightly greater than the base. The edges of the resection are approximated using interrupted 5-0 monofilament suture (b) . Whenever the tissue is resistant enough, it is preferable to position the knots on the ventricular side. In patients with a billowing commissure and prolapse caused by chordae elongation, either of the techniques of chordae shortening described in Chapter 10 can be used. In patients with endocarditis, an annuloplasty is necessary only if the annulus is dilated.
EXTENSIVE PROLAPSE RESULTING FROM CHORDAE RUPTURE
Usually seen in bacterial endocarditis, an extensive commissural prolapse resulting from chordae rupture requires a quadrangular resection involving all pathological tissue plus a 2-mm ridge in the case of endocarditis ( Fig. 12-3 ). After the quadrangular resection has been completed, leaflet continuity is restored using either an annular plication or a sliding leaflet technique, depending upon the commissure involved and the extent of the gap.
The optimal techniques in commissural prolapse with billowing leaflets aim at correcting both the prolapse and the billowing.
At the posterior commissure (a) 5- to 10-mm gap is treated by annular plication (b) , which approximates the leaflet remnants (c) . Then a magic stitch is used to restore a surface of commissural coaptation (d) . The fixation of the commissural edges by one or two nearby secondary chordae may be useful to further increase the coaptation (e) . The resection is completed by a ring annuloplasty (f) . A prolapse greater than 10 mm at the posterior commissure requires a quadrangular resection and a sliding leaflet technique ( Fig. 12-4 ). The P3 segment and if necessary a few millimeters of A3 are detached from the annulus (a, b) . Whenever distended, the commissural edge of the anterior leaflet is treated by an elective triangular resection to restore tension (b, c) . Compression sutures are placed to reduce the gap (c) . Leaflet remnants are secured to the annulus while exerting traction on the leaflet tissue to facilitate the sliding (d-f) .
One or two magic stitches are used to reconstruct the surface of coaptation (g) , leaving the commissure open (h) . A remodeling ring annuloplasty is used in all cases to reinforce the commissural reconstruction (i) .
At the anterior commissure , after a large valvular resection the plication technique should be avoided as a large annular plication could compromise the circumflex artery. A sliding leaflet technique is preferred.
The goal of the “magic stitch” is to restore a normal 5-mm bridge of commissural tissue prolonged by a large surface of leaflet coaptation.
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