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.