Relevance of Functional Mitral Regurgitation in Aortic Valve Stenosis

The clinical relevance of functional-mitral-regurgitation (FMR) in patients with aortic valve stenosis (AS) has been poorly studied using a quantitative approach. In addition, FMR prognostic value has mostly been analyzed after aortic valve replacement. Between 2010 and 2014 the echocardiograms of consecutive AS patients were retrospectively reviewed. Inclusion criteria were calcified aortic valve with transaortic-velocity >2.5 m/s and calculated mitral effective regurgitant orifice area (ERO) in the presence of mitral regurgitation. Organic mitral valve disease was an exclusion-criteria. Primary endpoint was heart failure or death under medical management. Secondary endpoint was heart failure or death. Eligible patients were 189, age 79 ± 8 years, 61% NYHA I/II, indexed aortic valve area (AVA) 0.55 ± 0.17 cm²/m². Mitral ERO was 7.6 ± 4.2 mm² (>10 mm² in 30% of patients). Longitudinal function (by S'-TDI) was associated with mitral ERO independently of ejection fraction and ventricular volumes (p = 0.01). Mitral ERO greater than 10 mm² (threshold identified by spline survival-modeling) was associated with severe symptoms (Odds ratio [OR] 3.1 [1.6 to 6.0]; p = 0.0006) and higher pulmonary-arterial-pressure (OR 3.0 [1.4 to 5.9]; p = 0.002). Follow-up was completed for 175 patients. After 4.7 [1.4 to 7.2] years, 87 (50%) patients underwent AVR, 66 (38%) had heart-failure, 64 (37%) died. No procedure on FMR was required. Mitral ERO was independently associated with primary and secondary endpoints both as continuous variable (Hazard ratio [HR] 1.15 [1.00 to 1.30]; p = 0.04 and HR 1.23 [1.05 to 1.43]; p = 0.01 per 5 mm² ERO increase) or as ERO> versus ≤10 mm². Adjustment for S'-TDI or subgroup-analysis did not affect results. The analysis by AVA revealed the incremental prognostic role of mitral ERO over AS severity. In conclusion, AS patients with concomitant FMR >10 mm² holds a higher risk during medical follow-up. FMR quantitation, even for volumetrically modest regurgitation, provides incremental prognostic information over AS severity.