[Prognostic performance of pulmonary effective arterial elastance in patients with heart failure]

Objective: To explore the predictive value of pulmonary effective arterial elastance (Ea) in patients with heart failure (HF). Methods: This is a retrospective cohort study, which retrospectively included 284 patients with HF who underwent right heart catheterization at Heart Failure Center in Fuwai Hospital between September 2013 and February 2022. Data regarding baseline clinical characteristics, hemodynamic profiles, and prognosis were collected. Ea was calculated as mean pulmonary arterial pressure/stroke volume. Patients were divided into Ea<0.555 group and Ea≥0.555 group according to the median value of Ea (0.555 mmHg/ml, 1 mmHg=0.133 kPa). The primary outcome was the primary clinical event, set as the first occurrence of a series of composite events, including all-cause death, heart transplantation, left ventricular assist device implantation, and HF rehospitalization. Event-free survival was defined as the absence of primary clinical events. Spearman correlation analysis was used to calculate the correlation coefficient between Ea and parameters reflective of right heart function. The Kaplan-Meier analysis was used to compare the different groups for the estimation of outcomes with the log-rank test. We used Cox proportional-hazards regression models to estimate hazard ratios (HR) for primary clinical event. Subgroup analysis was performed based on the age, gender, New York Heart Association (NYHA) functional class, left ventricular ejection fraction, presence of pulmonary hypertension, and serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) values. We used receiver operating characteristic (ROC) curve to calculate the area under the curve (AUC) of Ea for predicting event-free survival in patients with HF. Results: The median age was 51 years, and 206 (72.5%) patients were male. Ea and pulmonary vascular resistance (PVR) were significantly correlated (r=0.698, P<0.001). The correlation between Ea and pulmonary arterial elastance (PAC) were even more significant (r=-0.888, P<0.001). Compared with Ea<0.555 group, Ea≥0.555 group presented with higher serum NT-proBNP values (4 443 (1 792, 8 554) ng/L vs. 1 721 (480, 4 528)ng/L,P<0.001), higher PVR (3.4 (2.5, 4.7) Wood vs. 1.4 (0.9, 2.2) Wood, P<0.001), lower cardiac output (3.0 (2.3, 3.9) L/min vs. 4.3 (3.8, 4.9) L/min, P<0.001), and lower PAC (1.6 (1.3, 2.0) ml/mmHg vs. 4.0 (3.0, 6.0) ml/mmHg, P<0.001). The median follow-up time was 392 (166, 811) days. The Kaplan-Meier survival curve demonstrated a lower event-free survival rate in the Ea≥0.555 group compared to the Ea<0.555 group (P_log-rank<0.001). After multivariate adjustment, Ea (HR=1.734, P<0.001) remained significantly associated with the primary outcome. Subgroup analysis indicated that Ea was associated with the primary outcome across all subgroups. The AUC was 0.724 (P<0.001) for Ea to predict event-free survival calculated from ROC analysis. Conclusions: Ea is closely related to parameters reflective of right ventricular afterload. Increased Ea is an independent predictor of adverse outcomes in patients with HF.