Abstract 18241: Computational Fluid Dynamics (CFD) Exploration of Heart Rate Influence on Wall Shear Stress (WSS) in Coarctation of the Aorta(CoA): Implications for Beta-Blocker Therapy

Introduction: CoA's complex hemodynamics may lead to post-repair complications such as pseudoaneurysms. Understanding the effects of beta-blockers, successful in adult heart failure and potentially beneficial for children, is critical. We used a high-resolution image-based CFD model to study these effects on aortic WSS and turbulence in CoA patients. Hypothesis: Beta-blocker therapy may favorably influence hemodynamic turbulence stresses. Methods: Patient-specific CT scans informed 3D CoA aorta models. Large eddy simulations were conducted at neonatal heart rates of 100, 120, and 160 bpm. Aortic segments were divided into front and back regions based on jet flow impact. Results: Despite heart rate-induced turbulence, WSS distributions remained consistent across rates. Lower rates notably decreased maximal systolic WSS distal to the coarctation site but reduced localized WSS and its variability (6.49 +/- 3.29Pa) . Both front and back segments showed unique WSS patterns and peak systolic WSS increases with heart rate (0.1Pa per 10BPM & 0.07Pa/ per 10BPM, P>0.05) . Significantly higher stress was experienced by the front region (max: 95.2%, min: 70.4%) . Conclusions: Heart rate changes impact WSS values, indicating heart rate-lowering drugs like beta-blockers may alleviate hemodynamic stress. Despite overall lower WSS, the front region is more susceptible to shear stress at lower rates. This could guide beta-blocker therapy decisions and identify potential beneficiaries.