Impact of Epicardial Adipose Tissue on Right Cardiac Function and Prognosis in Pulmonary Arterial Hypertension.

BACKGROUND: Although epicardial adipose tissue (EAT) is linked to effects on survival in left-sided heart failure, the association between EAT and right-sided heart failure caused by pulmonary arterial hypertension (PAH) remains unknown. RESEARCH QUESTION: What are the potential impacts of EAT volume (EATV) on right ventricular function, biomarkers of myocardial injury, and long-term prognosis in patients with PAH?. STUDY DESIGN AND METHODS: A total of 135 age- and BMI-matched patients with PAH and 49 control subjects were included in this study. EATV was quantified by using cardiac magnetic resonance and was related to clinical correlates, N-terminal pro-brain natriuretic peptide, and cardiac function. Levels of EATV associated with the risk of clinical worsening were evaluated on a continuous scale (restricted cubic splines) and by previously defined centile categories with Cox proportional hazards regression models and Kaplan-Meier survival estimates. RESULTS: Compared with the control subjects, patients with PAH had a lower EATV (ln [EATV], 3.2 ± 0.8 mL vs 3.5 ± 0.7 mL; P = .034). The association of EATV with right ventricular end-diastolic volume (Pnonlinear = .001), right ventricular end-diastolic volume index (P < .001), right ventricular cardiac output (P = .003), N-terminal pro-brain natriuretic peptide (P = .030), and the risk of clinical worsening (P = .014) was U shaped. Compared with individuals with middle-level EATV, multivariable-adjusted hazard ratio for clinical worsening was 6.0 (95% CI, 1.3-27.8) for the individuals with low-level EATV and 6.8 (95% CI, 1.5-30.2) for high-level EATV in patients with PAH. INTERPRETATION: Patients with PAH had a decreased EATV compared with control subjects. EATV exhibited a U-shaped association with right ventricular function and biomarkers of myocardial injury in patients with PAH. Low and high levels of EATV might reduce long-term event-free survival in patients with PAH. CLINICAL TRIAL REGISTRATION: Chinese Clinical Trial Registry; No. ChiCTR2100049804; www.chictr.org.cn.