Left atrioventricular coupling index as a prognostic marker of cardiovascular events in heart failure with preserved ejection fraction

Abstract Background Left atrial (LA) structural remodeling is common and considered a marker of increased mortality in patients with heart failure with preserved ejection fraction (HFpEF). However, the left atrium is directly connected to the left ventricle during diastole and their functions are tightly coupled. A single left atrioventricular coupling index (LACI), defined by the ratio between the LA end-diastolic volume (LAV) and the LV end-diastolic volume (LVEDV) assessed by echocardiography, could be useful in the clinical routine to improve the risk stratification of HFpEF. Methods An analysis was performed from a prospective multicenter observational registry for HFpEF (PURSUIT-HFpEF Registry) conducted in the Osaka region of Japan. A total of 1231 patients hospitalized for acute heart failure (diagnosed by using the Framingham criteria) met the inclusion criteria: left ventricular ejection fraction (LVEF) ≥50% and brain natriuretic peptide ≥100 pg/ml. After excluding patients without persistent atrial fibrillation, we enrolled 863 patients (age, 81 ± 9 years; females, 56.1%; atrial fibrillation, 37.2%) whose LAV and LVEDV using the Simpson’s method were available at discharge. Heart failure hospitalizations and cardiovascular deaths were the primary endpoint. Results There was little correlation between the LAVI (median 50.2, interquartile range [IQR] 37.1–65.4 ml) and LVEDV (median 80.0, IQR 58.3–102.8 ml) (r = 0.16, p <0.001). As a result, the overall LACI was 0.94 (IQR 0.65–1.34). During a median follow-up of 729 (IQR 407–1180) days after discharge, 304 patients experienced the primary endpoint. The incidence incrementally increased with the LACI quartile groups (Q1: 26.9%, Q2: 37.5%, Q3: 34.0%, Q4: 42.6%, log-rank p = 0.005). After adjusting for age, gender, body mass index, left ventricular filling pressure, and serum brain natriuretic peptide levels, the LACI (hazard ratio, 1.19 per quartile increase; 95% confidence interval, 1.03-1.38; p = 0.021) was a significant predictor of the primary endpoint. Conclusions In the PURSUIT-HFpEF Registry, the degree of LA and LV structural remodeling differed between individuals. The LACI was a novel index for predicting cardiovascular outcomes in patients with HFpEF.