Abstract 15440: A Mechanical Model Using the Law of Laplace Explains the Localization of Late Gadolinium Enhancement in the Right Ventricle in Pulmonary Arterial Hypertension
B: Cardiac MRI (CMR) is becoming the the gold standard to evaluate the right ventricular (RV) structure and function in Pulmonary Arterial hypertension (PAH). Prior studies have identified that late gadolinium enhancement (LGE), occurs in PAH at the RV insertion points into left ventricle (LV). In PAH, LGE is correlated with decreased RV performance and predicts adverse outcomes. However, the basis for the restricted localization of LGE at the RV insertion points is unclear. We hypothesized that wall stress is highest at the RV-LV insertion points, potentially causing capillary stresses that leads to gadolinium extravasation M: Forty-one patients with PAH were included in the study. All patients had right heart catheterization (RHC) and CMR, within a 1 month interval. RV, LV and septal thickness was measured from the MRI at the end-systole. Intraventricular pressures were obtained from the RHC. Using Laplace's law, intramural tension for RV, LV walls and septum were determined at the RV-LV insertion points. The amplitude and the orientation of the total tension vector was calculated and compared between the LGE (+) and (-) groups. We divided our study group in 2 groups based on septal geometry: septum bowing toward RV (group1) and toward LV (group2). Curvatures at the upper and lower insertion points were calculated using a geometric model R: There was a significantly higher calculated tension at the insertion points in LGE (+) vs LGE (-) subgroups. This was evident both at both upper and lower insertion points C:The magnitude of shearing forces at the RV insertion sites correlates with the presence of LGE at these points. For LGE (+) patients, the shearing stress is higher for group2 when compared with group1. The mechanism by which LGE occurs is still unclear, but it appears to be predicted by increased stress at the insertion points. One hypothesis might be that the increase shearing forces intermittently open small spaces in the cardiac tissue that allows gadolinium to accumulate
- © 2011 by American Heart Association, Inc.