Prognostic Value of Pulmonary Elastance Methods in HFrEF: A Comparative Study.

Abstract

Background: Pulmonary vascular resistance (PVR) is commonly used to quantify right ventricular (RV) afterload in heart failure with reduced ejection fraction (HFrEF), yet it reflects primarily the steady component of pulmonary vascular load. Simplified pulmonary arterial elastance indices may better characterise the integrated arterial load experienced by the RV. The comparative prognostic value of different elastance formulations in HFrEF remains incompletely defined.

Method: This retrospective study included 352 patients with HFrEF who underwent right heart catheterisation between 2018 and 2022. Pulmonary elastance was calculated using three simplified formulations: systolic pressure-based elastance (EasPAP=sPAP/SV), transpulmonary gradient-based elastance (EaTPG=[mPAP PCWP]/SV), and pulse pressure-based elastance (EaPP=PP/SV), together with their indexed forms. Discriminatory performance was evaluated using receiver operating characteristic curve analysis. Associations with all-cause mortality were assessed using univariate and multivariable Cox regression analyses adjusted for age, New York Heart Association functional class, and renal function. Subgroup analyses by PVR (<3 vs ≥3 Wood units [WU]) and combined PVR-EaPP phenotype analyses were performed.

Results: During a median follow-up of 23 months, 139 patients (39.5%) died. In multivariable models, EasPAP (adjusted hazard ratio [HR] 1.31; p=0.002), EaPP (adjusted HR 1.63; p=0.005), and their indexed forms remained independently associated with mortality, whereas EaTPG-based formulations did not. In patients with PVR <3 WU, EasPAP and EaPP demonstrated stronger associations with mortality than in the high-PVR subgroup. In the combined phenotype analysis, elevated EaPP identified increased mortality risk irrespective of PVR category.

Conclusions: In patients with HFrEF undergoing right heart catheterisation, simplified pulsatile elastance indices, particularly EasPAP and EaPP, were independently associated with all-cause mortality. Notably, elevated EaPP identified higher-risk patients even in the absence of elevated PVR, suggesting that resistance-based metrics alone may not fully capture RV afterload. Prospective validation is warranted.