Shashi Raj, Basha Khan, Vimal Raj, Vamsidhar Reddy Pulagam, Bibhuti B. Das
Narayana Institute of Cardiac Sciences. Methodist Children’s Hospital.
India and United States
Journal of Heart and Lung Transplantation Open
JHLT Open 2026; 14:
DOI: 10.1016/j.jhlto.2026.100664
Abstract
Background: Cardiac magnetic resonance (CMR) enables comprehensive assessment of right ventricular (RV) function and ventricular-vascular interaction in pulmonary arterial hypertension (PAH). This exploratory pilot study compared echocardiographic and CMR-derived surrogate indices of RV-pulmonary arterial (RV-PA) coupling and examined indexed pulmonary artery compliance (PAc) in adolescents and young adults with PAH.
Methods: Twenty adolescents and young adults with Group 1 PAH underwent transthoracic echocardiography, CMR, and cardiac catheterization within 7 days. Echocardiographic TAPSE/systolic pulmonary artery pressure (sPAP) and CMR RV stroke volume/end-systolic volume were analyzed as noninvasive surrogates of RV-PA coupling; pressure-volume loop-derived end-systolic elastance/arterial elastance was not measured. Indexed PAc and pulmonary vascular resistance index (PVRi) were derived from catheterization and CMR data. Associations with WHO functional class, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and 6-minute walk distance (6MWD) were explored.
Results: Echocardiographic TAPSE/sPAP showed limited associations with clinical severity measures. CMR-derived RV indices showed stronger exploratory associations with NT-proBNP and 6MWD. In the prespecified multivariable model of the exercise endpoint, indexed PAc had the largest standardized coefficient (β = -0.78; 95% CI, -1.48 to -0.09; p = 0.031); PVRi and the imaging surrogates were not statistically significant. Estimates were imprecise because of the small sample.
Conclusions: In this small, hypothesis-generating cohort, CMR-derived RV-PA coupling and indexed PAc provided complementary physiologic information beyond the echocardiographic surrogate. These observations require validation against pressure-volume loop-derived coupling and prospective clinical outcomes.
Category
Heart Dysfunction Associated with Pulmonary Vascular Disease (Right)
Diagnostic Testing for Pulmonary Vascular Disease. Non-invasive Testing
Diagnostic Testing for Pulmonary Vascular Disease. Invasive Testing
Age Focus: Pediatric Pulmonary Vascular Disease or Adult Pulmonary Vascular Disease
Fresh or Filed Publication: Fresh (PHresh). Less than 1-2 years since publication
Article Access
Free PDF File or Full Text Article Available Through PubMed or DOI: Yes