Prognostic Stratification Based on Left Ventricular Diastolic Dysfunction and Coronary Microvascular Dysfunction in Patients Without Functional Coronary Artery Stenosis.

Background: The left atrial volume index (LAVi) is a sensitive surrogate marker for left ventricular diastolic dysfunction (LVDD) and is associated with poor outcomes. Although LVDD is associated with coronary microvascular dysfunction (CMD), the prognostic significance of coexisting elevated LAVi and CMD remains unclear. This study aimed to assess the significance of coexisting elevated LAVi and CMD. Methods and Results: We studied 330 patients who underwent intracoronary physiological assessment for suspected ischemia with non-obstructive coronary artery disease. Among these patients, 75 had LVDD, and 107 had coronary flow reserve (CFR) <2.5. Patients were classified into 4 groups: Group 1, normal LAVi and CFR; Group 2, elevated LAVi only; Group 3, impaired CFR only; and Group 4, abnormal LAVi and CFR. The primary endpoints were major adverse cardiovascular events (MACE), including cardiovascular death, acute coronary syndrome, and heart failure requiring hospitalization. During a median follow-up of 759 days, 16 (4.8%) patients experienced 18 events. Event-free survival was significantly lower in Group 4 than in the other groups (P<0.01). Conclusions: The coexistence of elevated LAVi and impaired CFR is associated with a significantly higher risk of MACE. The combination of LAVi and CFR may improve risk stratification in patients without epicardial coronary stenosis.