Right ventricular phenotyping in incident patients with idiopathic pulmonary arterial hypertension

Background: Right ventricular (RV) imaging has not a definite role in risk stratification of pulmonary arterial hypertension (PAH) patients. We tested the hypothesis that echocardiography-derived phenotypes, depicting different degrees of RV remodeling and dysfunction, may provide additional prognostic information to current risk stratification tools. Methods: Consecutive incident PAH patients aged ≥18 years, diagnosed between January 2005 and December 2021, underwent clinical assessment, right heart catheterization, standard echocardiography. Simple echocardiographic variables were combined in order to define a priori four phenotypes representing different degrees of RV dilatation and RV-pulmonary arterial (PA) coupling: Phenotype 1 with mildy dilated right ventricle and preserved RV-PA coupling (n = 152 patients); phenotype 2 with mildly dilated right ventricle and poor RV-PA coupling (n = 143 patients); phenotype 3 with severely dilated right ventricle and preserved RV-PA coupling (n = 201 patients); phenotype 4 with severely dilated right ventricle and poor RV-PA coupling, with or without severe tricuspid regurgitation (n = 519 patients). Risk stratification was based on the European Society of Cardiology/European Respiratory Society (ESC/ERS) 3-strata model and Registry to Evaluate Early and Long-Term PAH disease Management (REVEAL) 2.0 score. Results: These phenotypes were present in all risk groups. Notably, regardless of the ESC/ERS risk stratum assigned to the patient, phenotype 4 was associated with a 2-fold increase of the odds of death (HR 2.1, 95% CI 1.6-2.8, p < 0.001), while phenotype 1 was associated with a 71% reduction in the odds of dying (HR 0.29, 95% CI 0.18-0.47, p < 0.001). Conclusions: Echocardiography-derived phenotypes describing RV remodeling and dysfunction may provide prognostic information which is independent of and additional to the clinically defined risk in incident PAH patients.