Moderate ischemic mitral regurgitation at rest is associated with multiple functional vulnerabilities during exercise stress echocardiography.

BACKGROUND: Ischemic mitral regurgitation (IMR) is a common complication of coronary artery disease (CAD), often occurring after myocardial infarction. Even when moderate in severity, IMR is associated with adverse outcomes. AIMS: To compare functional vulnerability and outcomes in patients with different degrees of non-severe IMR. METHODS: This prospective international multicenter study included 126 patients with CAD (94 males; mean age 66 ± 9 years) from 13 institutions. Patients were divided into two groups: Group 1: Patients with moderate IMR, Group 2: Patients with absent-to-mild IMR. All patients underwent comprehensive exercise stress echocardiography (ESE). RESULTS: Despite similar left ventricular ejection fraction (LVEF) at rest (I = 47 ± 11% vs. II = 45 ± 11%, p = 0.141) and during stress (I = 47 ± 13% vs. II = 49.0 ± 12.0%, p = 0.525), Group 1 patients showed higher peak wall motion score index (I = 2.29 vs. II = 1.82, p < 0.002), more B-lines(I = 4 vs. II = 2, p < 0.002), reduced heart rate reserve (I = 1.32 vs. II = 1.58, p < 0.0001) and reduced LV contractile reserve (I = 1.11 vs. II = 1.35, p < 0.0005). During a median follow-up of 21 months, the composite endpoint (all-cause death, myocardial infarction, stroke, and hospitalization for heart failure) occurred more frequently in Group 1 (36.2% vs. 15.8%, p = 0.031). Mortality was significantly higher in patients with severe MR during SE compared with the remaining patients (37.5% vs. 8.3%, p = 0.006). CONCLUSION: Despite similar resting and stress LVEF, CAD patients with moderate IMR demonstrated a distinct profile of multiple functional vulnerabilities during ESE compared to patients with absent-to-mild IMR.