Regional and Global Biventricular Function in Pulmonary Arterial Hypertension: A Cardiac MR Imaging Study

Purpose: To determine whether chronic pulmonary arterial pressure (PAP) elevation affects regional biventricular function and whether regional myocardial function may be reduced in pulmonary arterial hypertension (PAH) patients with preserved global right ventricular (RV) function. Materials and Methods: After informed consent, 35 PAH patients were evaluated with right heart catheterization and cardiac magnetic resonance (MR) imaging and compared with 13 healthy control subjects. Biventricular segmental, section, and mean ventricular peak systolic longitudinal strain (E-LL), as well as left ventricular (LV) circumferential and RV tangential strains were compared between PAH patients and control subjects and correlated with global function and catheterization of the right heart indexes. Spearman rho correlation with Bonferroni correction was used. Multiple linear regression analysis was performed to determine predictors for regional myocardial function. Results: In the RV of PAH patients, longitudinal contractility was reduced at the basal, mid, and apical levels, and tangential contractility was reduced at the midventricular level. Mean RV E-LL positively correlated with mean PAP (r = 0.62, P < .0014) and pulmonary vascular resistance index (PVRI) (r = 0.77, P < .0014). Mean PAP was a predictor of mean RV E-LL (beta = .19, P = .005) in a multiple linear regression analysis. In the LV, reduced LV longitudinal and circumferential contractility were noted at the base. LV anteroseptal E-LL positively correlated with increased mean PAP (r = 0.5, P = .03) and septal eccentricity index (r = 0.5, P = .01). In a subgroup of PAH patients with normal global RV function, significantly reduced RV longitudinal contractility was noted at basal and mid anterior septal insertions, as well as the mid anterior RV wall (P < .05 for all). Conclusion: In PAH patients, reduced biventricular regional function is associated with increased RV afterload (mean PAP and PVRI). Cardiac MR imaging helps identify regional RV dysfunction in PAH patients with normal global RV function. (C) RSNA, 2012