Computational fluid dynamics investigation of the novel hybrid comprehensive stage II operation

Marwan Hameed; Ray Prather; Eduardo Divo; Alain Kassab; David Nykanen; Michael Farias; William M DeCampli

doi:10.1016/j.xjon.2021.04.009

Computational fluid dynamics investigation of the novel hybrid comprehensive stage II operation

JTCVS Open. 2021 Apr 27:7:308-323. doi: 10.1016/j.xjon.2021.04.009. eCollection 2021 Sep.

Authors

Marwan Hameed^{1

2}, Ray Prather^{1

2

3}, Eduardo Divo², Alain Kassab¹, David Nykanen³, Michael Farias³, William M DeCampli^{1

3

4}

Affiliations

¹ Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Fla.
² Department of Mechanical Engineering, Embry-Riddle Aeronautical University, Daytona Beach, Fla.
³ Pediatric Cardiology, Arnold Palmer Hospital for Children, Orlando, Fla.
⁴ Department of Clinical Sciences, College of Medicine, University of Central Florida, Orlando, Fla.

Abstract

Background: The hybrid comprehensive stage 2 (HCS2) procedure is a novel palliative operation applicable to a select subset of single ventricle patients with adequate native antegrade aortic flow to the upper body. Flow to the descending aorta, through the pulmonary outlet and ductal arch, is influenced by a stented intrapulmonary baffle connecting the branch pulmonary arteries. We used computational fluid dynamics (CFD) to elucidate the hemodynamic characteristics of this reconstruction.

Methods: We used multiscale CFD analysis of a synthetic, patient-derived HCS2 anatomic configuration with unsteady laminar flow conditions and a non-Newtonian blood model to quantify the resultant hemodynamics. The 3-dimensional CFD model was coupled to a 0-dimensional lumped parameter model of the peripheral circulation to determine the required boundary conditions.

Results: For the specific anatomy studied, the intrapulmonary baffle did not obstruct flow from the pulmonary trunk to ductal arch as long as the distance between the anterior pulmonary artery wall and baffle wall exceeded ∼7 mm. Vortex shedding off of the baffle wall did not develop, because of the short distance to the ductal arch. The stented baffle experienced significantly uneven "inward" loading from the systemic side. Pulmonary outlet flow separation distal to the baffle produced a low-speed recirculation region.

Conclusions: Hemodynamic patterns in this complex anatomy are generally favorable. Low flow recirculation could be mitigated by preoperative shape optimization. Calculated inward stresses on the pulmonary baffle can be used in the future to study baffle stent deformation, which is expected to be small.

Keywords: AA, ascending aorta; BC, boundary condition; CFD, computational fluid dynamics; CHD, congenital heart disease; DA, descending aorta; HCS2, hybrid comprehensive stage 2; HLHS, hypoplastic left heart syndrome; LCA, left coronary artery; LCCA, left common carotid artery; LPA, left pulmonary artery; LPM, lumped parameter model; LSCA, left subclavian artery; MPA, main pulmonary artery; ODE, ordinary differential equation; PA, pulmonary artery/trunk; RCA, right coronary artery; RCCA, right common carotid artery; RPA, right pulmonary artery; RSCA, right subclavian artery; SV, single ventricle; SVC, superior vena cava; VSD, ventricular septal defect; WSS, wall shear stress; computational fluid dynamics; congenital heart disease; hypoplastic left heart syndrome; lumped parameter model.