Abstract 11774: Right Ventricular Function and Myocardial Blood Volume Analyses by Convolutional Neural Network in Experimental Pulmonary Hypertension

Introduction: Survival of patients with pulmonary hypertension (PH) is highly dependent on the right ventricular (RV) function. Despite the association of various factors with adaptive or maladaptive RV phenotypes, the contribution of microvascular density to RV adaptation to pressure overload remains unclear. Hypothesis: This study aimed to evaluate the RV myocardial blood volume and its role in the RV adaptation to pressure overload. Methods: Both the University Animal Care Committee and the federal authorities for animal research of the Regierungsprasidium Giessen (Hessen, Germany) approved the study protocol. The study used adult Wistar-Kyoto rats and Sprague-Dawley rats to induce PH using SuHx and monocrotaline (MCT), respectively. Echocardiography, in vivo contrast-μCT, and invasive hemodynamic measurements were performed. The researchers used an artificial intelligence (AI)-based convolutional neural network (CNN) approach to reconstruct, segment, and analyze the cardiac μCT images. The RV functional reserve was evaluated during mCT acquisition and dobutamine stress test, and metabolomics analysis was performed. Results: The data showed that SuHx rats developed maladaptive cardiac function and RV-PA uncoupling. MCT rats exhibited adaptive RV function at days 14 and 21, but maladaptive function at day 35, which was associated with RV-PA uncoupling and reduced RV functional reserve. Impaired PKA-CREB signaling pathway was also found to be associated with the reduced RV functional reserve in the MCT rats. In both PH models, the absolute RV blood volume significantly increased with the development of RV hypertrophy, but the relative blood volume decreased, which was associated with maladaptive RV function Conclusions: This study is the first to demonstrate the use of AI CNN in post-processing of μCT-derived cardiac images from experimental PH models. Additionally, a single-beat PV loop was established for the first time in a rat model of PH by combining non-invasive and invasive techniques. The findings suggest that RV maladaptive function in rat models of PH is characterized by capillary rarefaction, impaired RV reserve in response to dobutamine infusion, which is associated with impaired PKA-CREB signaling pathway in the RV.