Clinical prognostic value of secondary mitral valve regurgitation

Functional mitral regurgitation (FMR) is a common complication of ischemic heart disease and severe dilated cardiomyopathy, and results from left ventricle (LV) deformation, tethering of the structurally normal mitral leafl ets and decreased LV force to close them (Enriquez-Sarano et al., Lancet 18;373(9672):1382–94, 2009). It is still disputed whether FMR is the primary cause for the poor outcome associated with it, or just a surrogate marker for worse left-ventricular dysfunction. However, the clear association of severe FMR with worse outcomes, independent of ejection fraction, age, and clinical presentation, suggests that the regurgitation is indeed causal of poor outcome. The prognostic role of mitral regurgitation is now substantiated by results from studies of patients with acute (Lamas et al., Circulation 96(3):827–33, 1997; Tcheng et al., Ann Intern Med 117(1):18–24, 1992), or chronic myocardial infarction (Bursi et al., Circulation 111(3):295–301, 2005; Grigioni et al., Circulation 103(13):1759–64, 2001; Lancellotti et al., Circulation 108(14):1713–7, 2003), dilated cardiomyopathy (Rossi et al., Heart 97(20):1675–80, 2011), clinical trials (Lamas et al., Circulation 96(3):827–33, 1997) and population studies (Bursi et al., Circulation 111(3):295– 301, 2005). Effective regurgitant orifice (ERO) and the change in ERO during exercise are considered the best prognostic parameters in patients with FMR (Grigioni et al., Circulation 103(13):1759–64, 2001; Lancellotti et al., Circulation 108(14):1713–7, 2003).