Aims: To define which echocardiographic parameters are related to the degree of functional mitral regurgitation (FMR) and to establish their relationship with clinical status, plasma B-type natriuretic peptide (BNP) levels, and prognosis in patients with non-ischaemic dilated cardiomyopathy (NICMP).
Methods and results: Ninety patients (mean age: 50 ± 14, 31% females) with NICMP and FMR were prospectively analysed by echocardiography. Global and local left ventricular remodelling parameters such as ejection fraction and sphericity index, inter-papillary muscle distance, coaptation to septal distance, and mitral annular area, as well as mitral valve deformation indices such as tenting area (TA) and tenting distance, were measured as indicators of FMR. Patients were defined as having severe FMR [effective regurgitant orifice area (EROA) ≥ 0.2 cm(2), n = 41] or non-severe FMR (EROA < 0.2 cm(2), n = 49) and followed for 15 ± 3 months. Multivariate regression analysis revealed that TA had the greatest ability to predict severe FMR at a cut-off level of 3.4 cm(2) with 82% sensitivity and 77% specificity. Patients with higher TA values (>3.4 cm(2)) had statistically higher BNP levels, worse functional status, more hospitalizations, and higher death rates. The plasma BNP level (P: 0.012) and TA (P: 0.056) were predictors of all-cause mortality. New York Heart Association class (P < 0.001) and TA (P: 0.005) were predictors of combined death or hospitalization on multivariate Cox's regression analysis.
Conclusion: Tenting area accurately reflects the degree of FMR at a cut-off value of 3.4 cm(2) and has a strong correlation with functional status, plasma BNP, mortality, and hospitalization rates. Tenting area is also an independent predictor of mortality and hospitalizations in patients with NICMP and FMR.