Sex-specific differences in echocardiographic parameters of risk stratification in pulmonary arterial hypertension

Background: In healthy subjects, sex-differences in right heart function have already been detected for various echocardiographic parameters.

Research question: The objective of the study was to investigate sex-differences in echocardiographic ESC/ERS risk stratification parameters and their impact on survival estimation in patients with pulmonary arterial hypertension (PAH).

Study design and methods: In this retrospective, cross-sectional study with a mean follow-up time of 3.2±2.65 (median 2.78) years clinical parameters including right atrial (RA), right ventricular (RV) area and tricuspid annular plane systolic excursion (TAPSE) divided by systolic pulmonary arterial pressure (sPAP) were assessed. Thresholds of ESC/ERS risk stratification were compared by multivariable Cox regression analysis.

Results: Of 748 PAH patients (mean age of 65±15 years, 63% female), men had significantly larger right heart size than women (RA area 21.76±7.64 cm² vs. 17.65±6.82 cm², p<0.001; RV area 24.02±7.15 cm² vs. 18.41±5.75 cm², p<0.001). This difference was consistent throughout all WHO functional classes (WHO-FC) and cardiac index (CI) risk groups, except for the RA area in CI high risk group and WHO-FC IV. At multivariable analysis, indexed values showed more pronounced differences for age-adjusted survival analysis compared to ESC/ERS risk stratification thresholds. TAPSE/sPAP showed no significant sex differences which makes this parameter a robust prognostic predictor.

Interpretation: This is the first study focusing on sex differences in right heart size obtained by echocardiography in PAH. For risk stratification indexation of RA-area to body surface area could be more considerate to body composition. In contrast, TAPSE/sPAP values were not sex-dependent and were a robust prognostic factor in PAH.