In Vitro Thrombosis Test for Ventricular Assist Devices.

The risk of thrombosis remains a significant concern in the development and clinical use of ventricular assist devices (VADs). Traditional assessments of VAD thrombogenicity, primarily through animal studies, are costly and time-consuming, raise ethical concerns, and ultimately may not accurately reflect human outcomes. To address these limitations, we developed an aggressive in vitro testing protocol designed to provoke thrombosis and identify potential high-risk areas within the blood flow path. This protocol, motivated by the work of Maruyama et al., employs a modified anticoagulation strategy and utilizes readily available components, making it accessible to most laboratories conducting in vitro blood testing of VADs. We demonstrated the utility of this method through iterative testing and refinement of a miniature magnetically levitated pediatric VAD (PediaFlow PF5). The method has been effective in identifying thrombogenic hotspots caused by design and manufacturing flaws in early VAD prototypes, enabling targeted improvements before advancing to animal studies. Despite its limitations, including the absence of pulsatile flow and the influence of donor blood characteristics, this protocol serves as a practical tool for early-stage VAD development and risk mitigation.