Functional mitral regurgitation in patients with aortic stenosis: prevalence, clinical correlates and pathophysiological determinants: a quantitative prospective study

AIMS: In patients with aortic stenosis (AS) functional mitral regurgitation (FMR) is frequent and is attributed to left ventricular (LV) remodelling and to aortic gradient. However, the association of these variables with mitral effective regurgitant orifice (ERO) is still unknown. METHODS AND RESULTS: We prospectively enrolled patients with aortic valve thickness and aortic velocities >2.5 m/s. We measured the LV diastolic (LVD) and systolic volumes (Simpson's method) and ejection fraction (EF) and longitudinal shortening (S-DTI), early, and late (A-DTI) lengthening velocities. The aortic valve area (AVA) and mean gradient (MG) were measured. FMR was considered in the absence of any alteration of mitral leaflet. ERO and regurgitant volume were measured by means of a proximal velocity surface area method method. One hundred and seventy-two patients formed the study population (mean age 76 ± 8 years; 50% female, EF 57 ± 14%, AVA 1.00 ± 0.4 cm(2)). Sixty-three per cent of patients had FMR (ERO range: 0.02 0.32 cm(2)). ERO was significantly associated with LVD (rho = 0.34; P = 0.0001), EF (r(s) = -0.35: P = 0.0001), and S-DTI (r = -0.57; P = 0.0001), A-DTI (rho = -0.47; P = 0.0001). In the subgroup of patients with a preserved EF (LVD <75 mL/m(2) and EF >55%), S-DTI, and A-DTI were the variables with the more powerful association with ERO (r(s) = -0.49 P = 0.0001 and r(s) = -0.40 P = 0.0001, respectively). In the overall population there was a non-significant negative association between the degree of AS and ERO (MG: r(s) = -0.08 P = 0.2 and AVA: r(s) = -0.08 P = 0.2).CONCLUSION: In AS patients, the LV function is a main determinant of FMR even if EF is preserved. The association between ERO and valvular gradient is complex but tended to be negative.