CFD analysis of the HVAD’s hemodynamic performance and blood damage with insight into gap clearance

• Published in: Biomechanics and modeling in mechanobiology Vol. 21; no. 4; pp. 1201 - 1215
• Main Authors: Gil, Antonio, Navarro, Roberto, Quintero, Pedro, Mares, Andrea, Pérez, Manuel, Montero, Jose Anastasio
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2022; Springer Nature B.V
• Subjects: Biological and Medical Physics; Biomedical Engineering and Bioengineering; Biophysics; Blood; Blood pumps; Centrifugal pumps; Computational fluid dynamics; Computer applications; Congestive heart failure; Damage assessment; Design parameters; Efficiency; Engineering; Flow velocity; Fluid dynamics; Fluid flow; Hemodynamics; Hemolysis; Hydrodynamics; Impellers; Low flow; Original Paper; Pressure head; Reynolds number; Theoretical and Applied Mechanics; Ventricle; Ventricular assist devices; Working conditions; Hemolysis; Shear stress; Centrifugal blood pump; Gap clearance; Operating map; Non-dimensional analysis
• ISSN: 1617-7959; 1617-7940
• DOI: 10.1007/s10237-022-01585-2

Mechanical circulatory support using ventricular assist devices has become commonplace in the treatment of patients suffering from advanced stages of heart failure. While blood damage generated by these devices has been evaluated in depth, their hemodynamic performance has been investigated much less. This work presents the analysis of the complete operating map of a left ventricular assist device, in terms of pressure head, power and efficiency. Further investigation into its hemocompatibility is included as well. To achieve these objectives, computational fluid dynamics simulations of a centrifugal blood pump with a wide-blade impeller were performed. Several conditions were considered by varying the rotational speed and volumetric flow rate. Regarding the device’s hemocompatibility, blood damage was evaluated by means of the hemolysis index. By relating the hemocompatibility of the device to its hemodynamic performance, the results have demonstrated that the highest hemolysis occurs at low flow rates, corresponding to operating conditions of low efficiency. Both performance and hemocompatibility are affected by the gap clearance. An innovative investigation into the influence of this design parameter has yielded decreased efficiencies and increased hemolysis as the gap clearance is reduced. As a further novelty, pump operating maps were non-dimensionalized to highlight the influence of Reynolds number, which allows their application to any working condition. The pump’s operating range places it in the transitional regime between laminar and turbulent, leading to enhanced efficiency for the highest Reynolds number.