Background .– There is currently uncertainty and debate regarding whether ischemic mitral regurgitation (MR) is a secondary epiphenomenon resulting from LV dysfunction or confers an independent effect on exercise capacity and outcomes; this debate impacts management.
Objective .– We tested whether ischemic MR negatively impacts exercise capacity, cardiovascular morbidity and mortality in patients (pts) with coronary artery disease (CAD) independent of LV dysfunction.
Methods .– Clinical follow-up over 5 years was obtained in 77 consecutive pts (age 64 ± 10 years, LVEF 54 ± 11%) with stable CAD who had exercise stress testing with perfusion imaging within 24 hours of echocardiography. Pts with active heart failure, ischemia, intrinsic valve disease, pulmonary and vascular disease were excluded. Exercise capacity (METs, peak double product) was tested for relation to MR (vena contracta [VC] and jet area), LV size and function, and pulmonary pressures. Cox proportional hazards analysis assessed whether MR predicted cardiovascular events, including hospitalization for heart failure, acute coronary syndrome, and myocardial infarction, and cardiovascular (CV) and total mortality.
Results .– By multivariate analysis, independent predictors of functional capacity (METs and peak double product) were MR vena contracta (VC; r 2 = 0.62, P < 0.0001) and LV end-diastolic volume (EDV; r 2 = 0.78, P = 0.03). MR jet area contributed similarly (r 2 = 0.61, P < 0.0001). MR VC > 2 mm (moderate ischemic MR) and age were the independent predictors of CV events and death (HR 6.72 for MR, P = 0.04).
Conclusion .– In patients with CAD, MR reduces exercise capacity and is associated with increased cardiovascular morbidity and mortality, independent of LV dysfunction, suggesting an adverse effect of MR volume load per se on functional capacity and outcomes.
