A Computational Model of Coarctation of the Aorta in Rabbits: Ventricular and Ascending Aortic Remodeling

ABSTRACT Coarctation of the aorta (CoA) is a common congenital cardiovascular lesion that typically presents as a localized narrowing of the proximal descending thoracic aorta just distal to the left subclavian artery. While improvements in surgical and catheter-based techniques have increased short-term survival, there is a high long-term risk of hypertension after CoA correction and a reduced average lifespan despite treatment. Computational models can be used to estimate ventricular and arterial remodeling, potentially serving as key tools in developing a mechanistic understanding of the interplay between pre-correction hemodynamics, post-correction recovery, and long-term hypertension risk. In this study, we developed a lumped parameter model of the heart and circulation to simulate aortic coarctation. We then used the model to estimate changes in ventricular thickness and ascending aortic compliance from imaging and catheterization data collected in rabbits with untreated and corrected CoA that used the current putative clinical treatment threshold (≥20 mmHg). Model outputs were compared to reported stroke volume, ejection fraction, systolic and diastolic ascending aortic pressures, peak ascending aortic flow, mean and peak aortic blood pressure gradients, and upper-to-lower body flow split, with all results falling within one standard deviation of the data for control, untreated CoA, and corrected CoA groups. In the untreated CoA and corrected simulations, a decrease in ascending aortic compliance was necessary to match reported hemodynamics, suggesting the rabbits exposed to CoA ≥20 mmHg underwent vascular remodeling that persisted after repair.