Computational fluid dynamics investigation of the novel hybrid comprehensive stage II operationCentral MessagePerspective
Marwan Hameed, PhD,
Ray Prather, PhD,
Eduardo Divo, PhD,
Alain Kassab, PhD,
David Nykanen, MD,
Michael Farias, MD, MS, MBA,
William M. DeCampli, MD, PhD
Affiliations
Marwan Hameed, PhD
Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Fla; Department of Mechanical Engineering, Embry-Riddle Aeronautical University, Daytona Beach, Fla
Ray Prather, PhD
Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Fla; Department of Mechanical Engineering, Embry-Riddle Aeronautical University, Daytona Beach, Fla; Pediatric Cardiology, Arnold Palmer Hospital for Children, Orlando, Fla
Eduardo Divo, PhD
Department of Mechanical Engineering, Embry-Riddle Aeronautical University, Daytona Beach, Fla
Alain Kassab, PhD
Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Fla
David Nykanen, MD
Pediatric Cardiology, Arnold Palmer Hospital for Children, Orlando, Fla
Michael Farias, MD, MS, MBA
Pediatric Cardiology, Arnold Palmer Hospital for Children, Orlando, Fla
William M. DeCampli, MD, PhD
Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Fla; Pediatric Cardiology, Arnold Palmer Hospital for Children, Orlando, Fla; Department of Clinical Sciences, College of Medicine, University of Central Florida, Orlando, Fla; Address for reprints: William M. DeCampli, MD, PhD, The Heart Center, Arnold Palmer Hospital for Children, 92 W Miller St, MP 307, Orlando, FL 32806.
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.
