Obesity-Related Differences in Pathomechanism and Outcomes in Patients With HFpEF: A CMR Study.

Background: Clinical significance of an integrated evaluation of epicardial adipose tissue (EAT) and the right ventricle (RV) in heart failure with preserved ejection fraction (HFpEF) is unknown.

Objectives: The authors investigated the potential of EAT and RV quantification for obesity-related pathophysiology and risk stratification in obese HFpEF patients using cardiovascular magnetic resonance (CMR).

Methods: A total of 150 patients (obese, body mass index ≥30 kg/m; n = 73, nonobese, body mass index <30 kg/m; n = 77) with a clinical diagnosis of HFpEF undergoing CMR were retrospectively identified. EAT volume surrounding both ventricles were quantified with manual delineation on cine images. Total RV volume (TRVV) was calculated as the sum of RV cavity and mass at end-diastole. The endpoint was the composite of all-cause mortality and first HF hospitalization.

Results: During a median follow-up of 46 months, 39 nonobese patients (51%) and 32 obese patients (44%) experienced the endpoint. EAT was a prognostic biomarker regardless of obesity and was independently correlated with TRVV. In obese HFpEF, EAT correlated with RV longitudinal strain (r = 0.32,  = 0.006), and increased amount of EAT and TRVV was associated with greater left ventricular end-diastolic eccentric index (r = 0.36,  = 0.002). The integration of RV quantification into EAT provided improved risk stratification with a C-statistic increase from 0.70 to 0.79 in obese HFpEF. Obese patients with EAT<130 ml and TRVV<180 ml had low risk (annual event rate 3.2%), while those with increased EAT ≥130 ml and TRVV ≥180 ml had significantly higher risk (annual event rate 11.8%;  < 0.001).

Conclusions: CMR quantification of EAT and RV structure provides additive risk stratification for adverse outcomes in obese HFpEF.