Patient-specific fluid-structure simulations of anomalous aortic origin of right coronary arteries

Michael X Jiang; Muhammad O Khan; Joanna Ghobrial; Ian S Rogers; Gosta B Pettersson; Eugene H Blackstone; Alison L Marsden

doi:10.1016/j.xjtc.2022.02.022

Patient-specific fluid-structure simulations of anomalous aortic origin of right coronary arteries

JTCVS Tech. 2022 Feb 25:13:144-162. doi: 10.1016/j.xjtc.2022.02.022. eCollection 2022 Jun.

Authors

Michael X Jiang^{1

2}, Muhammad O Khan³, Joanna Ghobrial⁴, Ian S Rogers⁵, Gosta B Pettersson⁶, Eugene H Blackstone^{6

7}, Alison L Marsden³

Affiliations

¹ Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio.
² Department of Pediatrics, Cleveland Clinic Children's Hospital, Cleveland, Ohio.
³ Department of Pediatrics (Cardiology), Department of Bioengineering, and Institute for Computational and Mathematical Engineering, Stanford University, Stanford, Calif.
⁴ Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio.
⁵ Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, Calif.
⁶ Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, Cleveland, Ohio.
⁷ Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio.

Abstract

Objectives: Anomalous aortic origin of the right coronary artery (AAORCA) may cause ischemia and sudden death. However, the specific anatomic indications for surgery are unclear, so dobutamine-stress instantaneous wave-free ratio (iFR) is increasingly used. Meanwhile, advances in fluid-structure interaction (FSI) modeling can simulate the pulsatile hemodynamics and tissue deformation. We sought to evaluate the feasibility of simulating the resting and dobutamine-stress iFR in AAORCA using patient-specific FSI models and to visualize the mechanism of ischemia within the intramural geometry and associated lumen narrowing.

Methods: We developed 6 patient-specific FSI models of AAORCA using SimVascular software. Three-dimensional geometries were segmented from coronary computed tomography angiography. Vascular outlets were coupled to lumped-parameter networks that included dynamic compression of the coronary microvasculature and were tuned to each patient's vitals and cardiac output.

Results: All cases were interarterial, and 5 of 6 had an intramural course. Measured iFRs ranged from 0.95 to 0.98 at rest and 0.80 to 0.95 under dobutamine stress. After we tuned the distal coronary resistances to achieve a stress flow rate triple that at rest, the simulations adequately matched the measured iFRs (r = 0.85, root-mean-square error = 0.04). The intramural lumen remained narrowed with simulated stress and resulted in lower iFRs without needing external compression from the pulmonary root.

Conclusions: Patient-specific FSI modeling of AAORCA is a promising, noninvasive method to assess the iFR reduction caused by intramural geometries and inform surgical intervention. However, the models' sensitivity to distal coronary resistance suggests that quantitative stress-perfusion imaging may augment virtual and invasive iFR studies.

Keywords: 3D, 3-dimensional; AAOCA, anomalous aortic origin of a coronary artery; AAORCA, anomalous aortic origin of a right coronary artery; CTA, computed tomography angiography; FFR, fractional flow reserve; FSI, fluid–structure interaction; RMSE, root-mean-square error; anomalous coronary artery; cardiac catheterization; computational flow dynamics; coronary computed tomography; coronary flow; iFR, instantaneous wave-free ratio.