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Published on: November 3, 2015
Shaping the Flow: Impact of Blade Shape on Performance and Hemocompatibility in Rotodynamic Blood Pumps
Benjamin Torner1, Simon Klocker1, Niccolò Crescenti1
1Department of Cardiac and Thoracic Aortic Surgery, Medical University of Vienna, Vienna, Austria.
Objectives:
Rotodynamic blood pumps (RBPs) must operate reliably across a wide range of clinical conditions, including off-design operating regimes. Although blade shape is known to influence off-design performance in conventional turbopumps, its impact on hydraulic performance and hemocompatibility in RBPs has not been systematically investigated. This study combines in silico and in vitro analyses to assess the effects of leading-edge geometry and blade thickness on performance (pressure head-flow rate characteristics, efficiencies) and hemocompatibility (damage index, DI) across multiple RBPs and operating conditions.
Methods:
Three representative RBPs, a cavopulmonary assist device, the CentriMag RBP, and a novel ventricular assist device, were investigated. Semi-circular, elliptical, and wedge-shaped leading edges were implemented, whereas three blade thickness configurations were analyzed.
Results:
Variations in leading-edge geometry resulted in minor differences in performance (< 3 percent in efficiency) and hemocompatibility (< 3% DI) across all devices and operating conditions. In contrast, blade thickness had a pronounced effect on performance under overload off-design operation, with thinner blades improving efficiency by up to 22%, while exhibiting only limited changes in hemocompatibility-related metrics (< 7% DI). The observed efficiency differences were primarily attributed to decreased friction losses caused by less channel blockage with thinner impeller blades.
Conclusions:
Overall, impeller blade shape plays a secondary role in hemocompatibility within the investigated pump types and operating conditions. This finding suggests that leading-edge optimization may be deprioritized relative to other hemocompatibility-critical geometry parameters in RBP design. Blade thickness, however, may lead to unfavorable channel blockage effects and therefore needs to be optimized with respect to manufacturing constraints and hydraulic performance.
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