Prediction of the ischemic origin of functional mitral regurgitation in patients with systolic heart failure through posterior mitral leaflet angle

BACKGROUND: Differentiating ischemic from non-ischemic functional mitral regurgitation (FMR) in patients with cardiomyopathy is important in terms of the therapeutic decisionmaking and prognosis, but might be clinically challenging. In this study, the deformation of mitral valve (MV) indices in the prediction of the etiology of FMR was assessed using 2D transthoracic and tissue Doppler echocardiography. METHODS: This case-control study was conducted from April 2015 to January 2016 in Imam Reza Hospital in Mashhad, Iran. The participants consisted of 40 patients with ischemic cardiomyopathy (ICM) and 22 with non-ischemic dilated cardiomyopathy (DCM) who referred to the heart failure clinic. Transthoracic echocardiography was performed using the conventional 2D and tissue Doppler imaging (TDI). MV tenting area (TA), coaptation distance (CD), anterior and posterior mitral leaflet angles (AMLA and PMLA), and regional systolic myocardial velocity (Sm) were measured. RESULTS: There were no significant differences in echocardiographic indices between the two groups, besides Sm and PMLA which were significantly lower and higher, respectively, in ICM subjects in comparison with DCM patients (P = 0.002). PMLA ≥ 40 degrees and Sm ≤ 4 cm/second have a relatively high value for discriminating the ischemic from non-ischemic origin of functional MR in subjects with systolic heart failure (sensitivity: 80.0% and 70.0%, specificity: 73.0% and 77.3%; P = 0.001 and P < 0.001; respectively). Multivariable logistic regression identified PMLA and anterior Sm as major determinants for ischemic MR {Odds ratio (OR) [95% confidence interval (CI)] = 0.89 (0.82-0.96), P = 0.003, o‎r (95% CI) = 0.29 (0.14-0.60), P = 0.001, respectively}. CONCLUSION: The present study showed that PMLA and Sm had an independent significant association with the mechanism of FMR. These findings are suggestive of the predictive role of mitral deformation echocardiographic indices in the determination of the etiology of FMR in systolic heart failure.