Enhancing thrombosis prevention in medical devices: The role of turbulence in washout performance using FDA benchmark nozzle model

Abstract

Background and objectives

Thrombosis presents a significant and potentially lethal risk in medical devices. Turbulence has been associated with increased thrombosis risk, primarily due to heightened shear stress and resultant blood damage. However, it can be inferred that turbulence might also enhance washout performance through efficient transport and mixing, thereby mitigating thrombosis. This study explores the underappreciated role of turbulence.

Methods

The FDA benchmark nozzle model was used as a representative framework for medical devices. To elucidate the isolated role of turbulence on washout performance, comparative simulations were conducted at Reynolds numbers of 500 and 6500 using Large Eddy Simulation (LES) and Menter's Shear Stress Transport (SST) k-ω turbulence models. Washout performance, a critical indicator in thrombosis, is evaluated by a passive scalar transport model.

Results

The validation results align well with published data, confirming the reliability of the simulations. Reynolds numbers and turbulence models play a crucial role in the washout performance. Turbulence improves volume washout by disrupting flow recirculation zones and enhancing the mixing of old and new blood. Furthermore, turbulence aids in surface washout by altering flow patterns in the near-wall region and increasing wall shear stress.

Conclusion and significance

The improved washout and dynamic environment facilitated by turbulence potentially minimize platelet adhesion and aggregation, which ultimately benefits the anti-thrombotic properties of medical devices. This research offers a novel perspective on the role of turbulence in thrombosis, extending beyond its traditionally recognized detrimental effects, and provides valuable insights into the design of specific flow patterns in achieving optimal washout performance in medical device applications. Further research is warranted to explore how to effectively leverage the washout-enhancing effects of turbulence while minimizing its potential adverse impacts.