Right Ventricular Architectural Remodeling and Functional Adaptation in Pulmonary Hypertension

Background:Global indices of right ventricle (RV) function provide limited insights into mechanisms underlying RV remodeling in pulmonary hypertension (PH). While RV myocardial architectural remodeling has been observed in PH, its effect on RV adaptation is poorly understood. Methods:Hemodynamic assessments were performed in 2 rodent models of PH. RV free wall myoarchitecture was quantified using generalized Q-space imaging and tractography analyses. Computational models were developed to predict RV wall strains. Data from animal studies were analyzed to determine the correlations between hemodynamic measurements, RV strains, and structural measures. Results:In contrast to the PH rats with severe RV maladaptation, PH rats with mild RV maladaptation showed a decrease in helical range of fiber orientation in the RV free wall (139o versus 97o; P=0.029), preserved global circumferential strain, and exhibited less reduction in right ventricular-pulmonary arterial coupling (0.029 versus 0.017 mm/mm Hg; P=0.037). Helical range correlated positively with coupling (P=0.036) and stroke volume index (P<0.01). Coupling correlated with global circumferential strain (P<0.01) and global radial strain (P<0.01) but not global longitudinal strain. Conclusions:Data analysis suggests that adaptive RV architectural remodeling could improve RV function in PH. Our findings suggest the need to assess RV architecture within routine screenings of PH patients to improve our understanding of its prognostic and therapeutic significance in PH.

Automated summary

This study investigated the effect of architectural remodeling on right ventricular (RV) adaptation in pulmonary hypertension (PH) using two rodent models. The results showed that in rats with mild RV maladaptation, there was a decrease in fiber orientation helical range in the RV free wall, preserved global circumferential strain, and less reduction in RV-pulmonary arterial coupling. These findings suggest that adaptive RV architectural remodeling could improve RV function in PH.