Degenerative mitral valve regurgitation: best practice revolution

Abstract

Degenerative mitral valve disease often leads to leaflet prolapse due to chordal elongation or rupture, and resulting in mitral valve regurgitation. Guideline referral for surgical intervention centres primarily on symptoms and ventricular dysfunction. The recommended treatment for degenerative mitral valve disease is mitral valve reconstruction, as opposed to valve replacement with a bioprosthetic or mechanical valve, because valve repair is associated with improved event free survival. Recent studies have documented a significant number of patients are not referred in a timely fashion according to established guidelines, and when they are subjected to surgery, an alarming number of patients continue to undergo mitral valve replacement. The debate around appropriate timing of intervention for asymptomatic severe mitral valve regurgitation has put additional emphasis on targeted surgeon referral and the need to ensure a very high rate of mitral valve repair, particularly in the non-elderly population. Current clinical practice remains suboptimal for many patients, and this review explores the need for a 'best practice revolution' in the field of degenerative mitral valve regurgitation.

Figure 1

Spectrum of degenerative mitral disease. There is a spectrum of degenerative disease ranging from fibroelastic deficiency (FED) to Barlow's disease. In isolated FED there is a deficiency of collagen, with thin transparent leaflets and typically a ruptured thin chord. In long-standing prolapse, secondary myxomatous pathologic changes may occur in the prolapsing segment, resulting in leaflet thickening and expansion (FED+). Forme fruste designates degenerative disease with excess tissue with myxomatous changes in usually more than one leaflet segment, but usually does not involve a large valve size, distinguishing it from Barlow's disease. In the later, the hallmarks are large valve size, with diffuse myxomatous changes and excess leaflet tissue, with thickened, elongated, and often ruptured chordae.

Figure 2

Echocardiographic differentiation of degenerative mitral disease. (A) Fibroelastic deficiency with a ruptured thin chord to P3 (posterior lateral scallop). (B) Three-dimensional transoesophageal echocardiography volume rendering of the same valve. (C) Three-dimensional rendering of the same valve from a three-dimensional data set using quantitative analysis (red area corresponds to prolapsing area). (D) Barlow's disease with multi-segment prolapse and excess leaflet tissue. (E) Three-dimensional rendering volume rendering of the same valve. (F) Three-dimensional rendering of the same valve from a three-dimensional data set using quantitative analysis (red areas correspond to prolapsing areas).

Figure 3

Mitral surgery via right thoracotomy. The patient is in a supine position, and cannulated for cardiopulmonary bypass via the groin vessels. The valve is exposed through a right mini-thoracotomy and visualization is assisted by a videoscope. Shown in the inset is the aorta clamped, with a caridioplegia needle inserted in the aorta, and the mitral valve as seen by the surgeon with the atrium opened.

Figure 4

Triangular resection and ring annuloplasty. (A) Fibroelastic deficiency with P2 (posterior middle scallop) prolapse. (B) Dashed lines represent area of leaflet to be excised. (C) Reconstructed leaflet after triangular resection. (D) Completed repair after ring annuloplasty.

Figure 5

Gore-Tex loop technique and ring annuloplasty. (A) Fibroelastic deficiency with A3 (anterior lateral scallop prolapse). (B) Gore-Tex loops are constructed, and the apparatus is attached to the fibrous tip of the papillary muscle. (C) Individual loops are attached to the prolapsing segment margin. (D) Completed repair after ring annuloplasty.