Right Ventricular Function Under Increased Afterload: Comparison Between Pulmonary Hypertension (PH) and Pulmonary Stenosis (PS)

Abstract

Background. Pulmonary hypertension (PH) and pulmonary stenosis (PS) both increase right- ventricular (RV) afterload but via distinct pathophysiology. Comparative data on RV remodelling across these conditions are limited. Methods. We performed a retrospective, observational comparison of consecutive adult transthoracic echocardiograms from a single centre (October 2023–July 2025). A PS cohort (n=70) was assembled first; a PH cohort (n=70) from the same period was then size-matched for head-to-head comparisons. Routine laboratory measurements were extracted; full RIMP, RV/LV basal ratio, and most S:D ratios were measured offline by a single investigator using prespecified rules. Primary domains were RV function (FAC, 3D RVEF, TAPSE, S′, free-wall strain, RIMP, S:D, TAPSE/RVSP), loading indices (RAP category, RVOT A-wave, RVOT acceleration time), geometry (RVD1/RVD2, RV/LV ratio, RVOT-PLAX, 3D volumes), wall thickness (absolute/classification), and valve regurgitation (TR/PR). Non-parametric tests were used; subgroup analyses contrasted mild vs moderate–severe disease. Results. Compared with PS, PH showed worse global systolic performance (lower FAC and 3D RVEF), adverse timing/diastolic behaviour (higher RIMP and S:D), shorter RVOT acceleration time, and a right-shifted RAP profile (all p≤0.05). Longitudinal indices (TAPSE, S′) were similar; free-wall strain differences were borderline. Geometrically, PH had a larger RV/LV basal ratio and larger RVOT-PLAX; absolute RVD1/RVD2 were similar. RV wall thickness and thickness-classification distributions were comparable. Valve phenotype diverged: TR was more advanced in PH, PR in PS. Differences were most pronounced in the moderate–severe strata. Conclusions. PH is characterised by reduced global RV systolic function and adverse timing/diastolic indices with a right-shifted RAP profile, whereas longitudinal indices are similar and free-wall strain differences are borderline. Geometry diverges (higher RV/LV ratio and RVOT-PLAX in PH; similar RVD1/RVD2), wall thickness is comparable, and valve phenotypes differ (more TR in PH, more PR in PS), with contrasts most evident in moderate–severe disease