Computational Fluid Dynamic Simulations of Aortic Coarctation Comparing the Effects of Surgical- and Stent-Based Treatments on Aortic Compliance and Ventricular Workload

Objectives: In this work, we examine the effects of stent-induced aortic stiffness on cardiac workload and blood pressure using computational fluid dynamic simulations. Background: Treatment of aortic coarctation (CoA) consists of either open, surgical repair or angioplasty with or without stenting. Although stenting is a minimally invasive alternative to surgery, aortic stiffness increases in the stented section. Concern over this increased stiffness has long been argued to be detrimental to the overall vascular health of the patient. Methods: MR imaging was performed on a 15-year-old female with CoA. A 3D model of the large thoracic arteries was created, and the heart and downstream vasculature were represented by lumped parameter models at the model inlet and outlets, respectively. A deformable wall assumption was used in conjunction with variable wall properties and tissue support, and 3D velocity, pressure, and wall dynamics were computed. The lumped parameter values and wall properties were tuned to match the mean flow and aortic deformation as measured by MRI. The CoA was then virtually removed from the model representing an end-to-end surgical correction. In a second model, the repaired section was prescribed to be nearly rigid, representing stenting. All other variables remained the same. Results: When compared to surgery, stenting resulted in clinically negligible increases in cardiac work (0.4%) and no change in mean blood pressure. Conclusions: This pilot study suggests CoA stenting may not affect cardiac work to any significant degree as is commonly believed in the clinical community. (C) 2011 Wiley-Liss, Inc.