Abstract 14381: Patient-specific Fluid Structure Interaction Simulations of Anomalous Origins of Right Coronary Arteries in Adults Correlate With Measured Instantaneous Wave-free Ratio

Abstract

Introduction: Anomalous coronaries are associated with ischemia and sudden death, but the recommendation to undergo surgery is often uncertain, especially for asymptomatic individuals with an anomalous aortic origin of the right coronary artery (AAORCA). For risk stratification, dobutamine-stress instantaneous wave-free ratio (iFR) is increasingly used. Meanwhile, advances in fluid-structure interaction (FSI) modeling have enabled the simultaneous simulation of blood flow and tissue deformation that may elucidate the mechanism of ischemia in AAORCA. Hypothesis: We hypothesized that the iFR simulated by patient-specific FSI models of AAORCA correlates with the measured iFR at rest and dobutamine-stress, and the hemodynamic mechanism is mainly due to the intramural geometry. Methods: Using the Simvascular software package, we constructed 6 FSI models of the AAORCA which encompassed the aortic root, the intramural course (if present), and coronary outlets coupled to lumped parameter networks that included the dynamic microvascular compression. Each model was customized to the patients’ computed tomography angiography, vitals, and cardiac output. Results: All 6 AAORCAs had an interarterial course, and all but one had an intramural course. Measured iFRs ranged from 0.98 to 0.95 at rest, and from 0.95 to 0.80 with dobutamine-stress. The FSI model yielded realistic pressures and flows waveforms (Fig. 1). After we tuned the resistances to achieve flow rates at stress to be triple those at rest, the FSI simulations adequately matched the measured iFR (r = 0.85, RMSE = 0.04). Conclusions: Patient-specific FSI modeling is a promising non-invasive tool to assess the hemodynamic effects of AAORCA including the intramural course. However, the iFR’s sensitivity to the flow rate suggests a future role for quantitative stress-perfusion imaging to augment the iFR measurements for AAOCA risk stratification.