Abstract 10885: Decreased Hydraulic Force Contributes to Diastolic Dysfunction and Associates with Survival Beyond Conventional Measures of Diastolic Dysfunction

Abstract

Introduction: Decreased hydraulic force has recently been identified as a mechanism contributing to left ventricular (LV) diastolic dysfunction and heart failure with preserved ejection fraction (HFpEF). However, it is unclear if hydraulic forces are independently associated with survival. Hypothesis: Decreased diastolic hydraulic force, estimated as the atrioventricular area difference (AVAD), is associated with survival independent of conventional diastolic dysfunction measures. Methods: Patients (n=37947, median [interquartile range] 4.9 [2.9-8.0] years follow-up, 6103 events) were selected from the National Echo Database Australia based on the presence of relevant transthoracic echocardiographic measures, LV ejection fraction (LVEF) ≥ 50%, heart rate 50-100 beats/minute, the absence of moderate or severe valvular disease, pericardial disease or mitral annular calcification, and no prior cardiac surgery. AVAD was calculated as the cross-sectional area difference between the LV and left atrium (LA) using circular approximation of LV end-diastolic diameter and LA end-systolic diameter. LV diastolic dysfunction grading was performed according to 2016 guidelines. Results: In multivariable linear regression, AVAD was weakly associated with E/e’, e’, peak tricuspid regurgitation velocity, and LVEF (global adjusted R2=0.11, p<0.001), but not associated with left atrial volume index (p=0.83). In multivariable Cox regression, there was an association with survival for both AVAD (chi-square 279, hazard ratio (HR) [95% confidence interval] 1.23 [1.20-1.26], p<0.001) and diastolic dysfunction grading (chi-square 1217, HR 3.21 [3.00-3.42], p<0.001). In a separate multivariable model, there was an association with survival for both AVAD (chi-square 371, HR 1.27 [1.24-1.30], p<0.001) and E/e’ (chi-square 1020, HR 1.39 [1.36-1.42], p<0.001). Conclusions: Decreased hydraulic force, estimated as AVAD, is associated with diastolic dysfunction, and provides prognostic information beyond conventional measures used to grade diastolic dysfunction. This suggests that increased LA size relative to LV size is a potential therapeutic target in HFpEF.