Blood Pump Design Variations and Their Influence on Hydraulic Performance and Indicators of Hemocompatibility

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Medical Device Design

Background:

• Ventricular assist devices (VADs) are vital for heart failure patients but have high adverse event rates.
• Many complications are linked to the complex flow dynamics within the blood pump.
• Optimizing VAD geometry is essential for improving patient outcomes.

Purpose of the Study:

• To investigate how design parameters of a centrifugal blood pump affect its hemodynamic performance and hydraulic efficiency.
• To identify design features that minimize potentially damaging flow conditions and hemocompatibility issues.

Main Methods:

• Developed a centrifugal blood pump prototype adhering to industrial standards.
• Employed computational fluid dynamics (CFD) to analyze hemodynamics and hydraulic performance.
• Systematically varied design parameters: clearance gaps, impeller blade count, and shroud design (semi-open vs. closed).
• Assessed flow fields using Eulerian and Lagrangian analyses, shear stress histograms, and hemocompatibility indicators.

Main Results:

• Larger clearance gaps and increased blade numbers were associated with higher shear stress conditions.
• Reduced stagnation and recirculation zones were observed with fewer blades and semi-open impellers.
• Smaller clearance gaps, however, increased stagnation and recirculation.
• The Lagrangian hemolysis index correlated negatively with hydraulic efficiency but showed no correlation with Eulerian metrics.

Conclusions:

• Centrifugal blood pump design significantly impacts hemocompatibility and hydraulic performance.
• Design choices like clearance gap, blade count, and shroud type offer trade-offs between flow efficiency and blood damage.
• Further research using Lagrangian metrics is recommended for accurate hemocompatibility assessment in VADs.