Association of right ventricular echocardiographic parameters with WHO functional class in patients with pulmonary artery hypertension

Abstract Background In pulmonary arterial hypertension (PAH), the right ventricle (RV) is exposed to an increased afterload. As the disease progresses, the RV dilates, leading to impaired RV function and worsening symptoms. Although different echocardiographic indices are used to assess RV size and function, a comprehensive analysis of their association with functional class in PAH is lacking. Purpose The aim of the study was to assess the diagnostic performance of different echocardiographic parameters of RV size and function and their association with functional class in patients with PAH. Methods The retrospective study enrolled consecutive patients with PAH who underwent comprehensive echocardiographic examination and right heart catheterisation at our centre between 2018 and 2024. Functional class was assigned using World Health Organization (WHO) functional class classification. Patients were divided into two groups: one comprising patients with no or mild symptoms (WHO class I or II), and the other group comprising severely symptomatic patients (WHO class III or IV). Diagnostic performance of RV echocardiographic parameters was assessed and parameters were dichotomised using a cut-off value determined by a receiver operating characteristic curve. Univariate and multivariate logistic binary regression were performed to identify independent echocardiographic RV parameters associated with symptoms severity. Results The study involved 108 patients (age 63 years (21-84 years), 56% women) with a mean systolic pulmonary artery pressure of 64 mmHg±21 mmHg. In our study cohort 45 patents (42%) were classified as severely symptomatic (WHO class III and IV). At receiver operating characteristic analysis, RV free wall strain (RVFWS, area under the curve (AUC) = 0.71; 95% CI, 0.62-0.80) showed stronger association with severe symptoms than tricuspid annular plane systolic excursion (AUC = 0.68; 95% CI, 0.59-0.77) and fractional area change (0.68; 95% CI, 0.58-0.77) (Panel A). Among RV size parameters right ventricular end-diastolic area (RVEDa, AUC = 0.62; 95% CI, 0.52-0.71) showed better diagnostic performance for identifying severe symptoms than RV basal end-diastolic diameter (Panel B). The RVFWS cut-off associated with severe symptoms was > -16,7% and RVEDa cut-off was > 29 cm2. In univariate analysis, RVFWS > -16,7% and RVEDa >29 cm2 were associated with 3.1-fold and 2.6-fold increased risk of being severely symptomatic, respectively. In multivariate model, RVFWS and RVEDa remained independently associated with symptom severity (all P