Ischemic and Functional Mitral Regurgitation in Heart Failure: Natural History and Treatment

Abstract

Functional mitral regurgitation (FMR) occurs when normal or nearly normal mitral leaflets are prevented from proper coaptation by underlying left ventricular (LV) dysfunction, mitral annular dilation, or both. FMR is associated with an adverse prognosis in nonischemic or ischemic LV dysfunction. Multiple studies have confirmed that even mild FMR portends a worse prognosis, and that the risk of FMR is independent of LV volumes and other clinical risk factors. FMR can be difficult to quantitate echocardiographically because it is load dependent and can vary considerably from exam to exam. There is a systematic tendency to underestimate FMR severity by echocardiography because the regurgitant orifice in FMR is typically elliptical, but the formula for calculating regurgitant orifice area assumes circular geometry. Treatment of FMR begins with guideline-directed medical therapy (GDMT) for LV dysfunction and heart failure, including cardiac resynchronization, if indicated. Revascularization should be considered for ischemic FMR, when indicated. Finally, mitral valve surgery should be considered in patients undergoing CABG in whom moderate or greater FMR is present, and also when severe symptomatic FMR persists despite optimal GDMT and revascularization. Percutaneous options for treatment of FMR are in development but are not currently approved in the US.

Papillary Muscle Free Strain in Patients with Severe Degenerative and Functional Mitral Regurgitation

“…In FMR, tethering of the mitral leaflets is often on the posterior leaflet and particularly on the posteromedial scallop. 24 According to this finding, as the posterior leaflet length increases, tethering of the mitral leaflet diminishes and PM function improves.…”

Clinical outcomes of conventional surgery versus MitraClip® therapy for moderate to severe symptomatic mitral valve regurgitation in the elderly population: an institutional experience

“…Some studies provided insight into potential poorer prognosis for patients with functional MR and left ventricular dysfunction and this is especially true for patients with recent acute myocardial infarction and for patients with chronic ischemic and non ischemic cardiomyopathy [14]. It was shown that even with the current GDMT, there was always a tendency to adverse prognosis due to untreated ischemic functional MR.…”

Factors influencing left ventricular outflow tract obstruction following a mitral valve‐in‐valve or valve‐in‐ring procedure, part 1

“…No two mitral rings are similar and their use is surgeon specific [20][21][22][23]. Broadly, the mitral rings can be classified depending on their rigidity as rigid, semi-rigid, or flexible.…”