Functional mitral valve regurgitation: repair or replacement?
Long term outcomes primarily depend on left ventricular function
Primary mitral valve disease involves damage to leaflet or chordal tissue,1 whereas functional (or secondary) mitral regurgitation (MR) typically involves a combination of mitral annular dilatation and leaflet restriction caused by ventricular dysfunction in patients with normal leaflets and chordae. Assessing the severity of regurgitation in secondary MR is more difficult than in primary MR, as the regurgitant orifice area is often underestimated by echocardiography because of its crescent shape during systole. Left ventricular stroke volume is usually reduced in secondary MR, so that lesser degrees of regurgitant volume are more significant.
Mitral annular dilatation can follow left ventricular dilatation caused by dilated cardiomyopathy or myocardial infarction. Mitral and tricuspid dilatation can also occur as a consequence of atrial dilatation resulting from long-standing atrial fibrillation. This usually affects the tricuspid to a greater extent, but can still cause symptomatic MR that requires surgery.
Functional MR is thus a left ventricular condition,2 and anti-failure medical therapy is the critical first component of management. Some patients present with dyssynchrony of ventricular contraction, and can benefit from biventricular pacing.3…