title: Computational simulations of flow dynamics and blood damage through a bileaflet mechanical heart valve scaled to pediatric size and flow.
abstract: Despite pressing needs, there are currently no FDA approved prosthetic valves available for use in the pediatric population. This study is performed for predictive assessment of blood damage in bileaflet mechanical heart valves (BMHVs) with pediatric sizing and flow conditions. A model of an adult-sized 23 mm St. Jude Medical (SJM) Regent(™) valve is selected for use in simulations, which is scaled in size for a 5-year old child and 6-month old infant. A previously validated lattice-Boltzmann method (LBM) is used to simulate pulsatile flow with thousands of suspended platelets for cases of adult, child, and infant BMHV flows. Adult BMHV flows demonstrate more disorganized small-scale flow features, but pediatric flows are associated with higher fluid shear stresses. Platelet damage in the pediatric cases is higher than in adult flow, highlighting thrombus complication dangers of pediatric BMHV flows. This does not necessarily suggest clinically important differences in thromboembolic potential. Highly damaged platelets in pediatric flows are primarily found far downstream of the valve, as there is less flow recirculation in pediatric flows. In addition, damage levels are well below expected thresholds for platelet activation. The extent of differences here documented between the pediatric and adult cases is of concern, demanding particular attention when pediatric valves are designed and manufactured. However, the differences between the pediatric and adult cases are not such that development of pediatric sized valves is untenable. This study may push for eventual approval of prosthetic valves resized for the pediatric population. Further studies will be necessary to determine the validity and potential thrombotic and clinical implications of these findings.
authors.affiliation: G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: B Min
authors.initials: BM
authors.lastname: Yun
authors.affiliation: New York University Langone Medical Center and School of Medicine, New York, NY, USA.
authors.forename: Doff B
authors.initials: DB
authors.lastname: McElhinney
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Shiva
authors.initials: S
authors.lastname: Arjunon
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Lucia
authors.initials: L
authors.lastname: Mirabella
authors.affiliation: G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA; Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Cyrus K
authors.initials: CK
authors.lastname: Aidun
authors.affiliation: G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA; The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA; Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA; School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA. Electronic address: ajit.yoganathan@bme.gatech.edu.
authors.forename: Ajit P
authors.initials: AP
authors.lastname: Yoganathan
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology*; D001792:Blood Platelets / Q000502:physiology; D002675:Child, Preschool; D003198:Computer Simulation; D003326:Coronary Circulation; D006350:Heart Valve Prosthesis; D006351:Heart Valves / Q000502:physiology*; D006801:Humans; D007223:Infant; D008955:Models, Cardiovascular; D011673:Pulsatile Flow; D013927:Thrombosis / Q000209:etiology
keywords: Bileaflet mechanical heart valve; Blood damage; Computational fluid dynamics CFD; Pediatric flows; Thromboembolic potential