Open Access

ARTICLE

Computational simulation of postoperative pulmonary flow distribution in Alagille patients with peripheral pulmonary artery stenosis

Weiguang Yang¹, Frank L. Hanley², Frandics P. Chan³, Alison L. Marsden^1,4, Irene E. Vignon-Clementel⁵, Jeffrey A. Feinstein^1,4

1 Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, California, USA
2 Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, California, USA
3 Department of Radiology, Stanford University School of Medicine, Stanford, California, USA
4 Department of BioEngineering, Stanford University School of Medicine, Stanford, California, USA
5 INRIA and Sorbonne Universités UPMC, Univ. Paris 6, Laboratoire Jacques-Louis Lions, Paris, France

* Corresponding Author: Weiguang Yang, Research Associate, Division of Pediatric Cardiology, Stanford University School of Medicine, 750 Welch Rd, Suite 325, Palo Alto, CA 94304. Email:

Congenital Heart Disease 2018, 13(2), 241-250. https://doi.org/10.1111/chd.12556

Abstract

Background: Up to 90% of individuals with Alagille syndrome have congenital heart diseases. Peripheral pulmonary artery stenosis (PPS), resulting in right ventricular hypertension and pulmonary flow disparity, is one of the most common abnormalities, yet the hemodynamic effects are illdefined, and optimal patient management and treatment strategies are not well established. The purpose of this pilot study is to use recently refined computational simulation in the setting of multiple surgical strategies, to examine the influence of pulmonary artery reconstruction on hemodynamics in this population.
Materials and Methods: Based on computed tomography angiography and cardiac catheterization data, preoperative pulmonary artery models were constructed for 4 patients with Alagille syndrome with PPS (all male, age range: 0.6–2.9 years), and flow simulations with deformable walls were performed. Surgeon directed virtual surgery, mimicking the surgical procedure, was then performed to derive postoperative models. Postoperative simulation-derived hemodynamics and blood flow distribution were then compared with the clinical results.
Results: Simulations confirmed substantial resistance, resulting from preoperative severe ostial stenoses, and the use of newly developed adaptive outflow boundary conditions led to excellent agreement with in vivo measurements. Relief of PPS decreased pulmonary artery pressures and improved pulmonary flow distribution both in vivo and in silico with good correlation.
Conclusions: Using adaptive outflow boundary conditions, computational simulations can estimate postoperative overall pulmonary flow distribution in patients with Alagille syndrome after pulmonary artery reconstruction. Obstruction relief along with pulmonary artery vasodilation determines postoperative pulmonary flow distribution and newer methods can incorporate these physiologic changes. Evolving blood flow simulations may be useful in surgical or transcatheter planning and in understanding the complex interplay among various obstructions in patients with peripheral pulmonary stenosis.

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