Medicine in Novel Technology and Devices (Dec 2022)
A new way to evaluate thrombotic risk in failure heart and ventricular assist devices
Abstract
Thrombosis is one of the main complications in patients implanted with ventricular assist device (VAD). The complicated structure and disturbed flow field within failure heart and blood pump play an important role in thrombosis formation. In this study, the influence of Left ventricular (LV) volumes on flow field contributing to thrombosis formation within failure heart and VAD was investigated. Computational Fluid Dynamics (CFD) methods were employed to investigate the effect of different LV volumes on the thrombogenic potential of failure heart and VAD. Lagrangian methods were utilized to obtain information on platelet voyage trajectories. The concepts of mean and threshold of stress accumulation and residence time were introduced to accurately assess the likelihood of thrombus. Eulerian methods were used to identify thrombus-prone locations. CFD results showed that residence time (RT) was the main cause of thrombus formation in the failure heart, and the percentage of platelet trajectories above the RT threshold increased significantly with increasing LV volume. The RT in the left atrial appendage and LV increased significantly with LV volume increasing, which indicated that thrombus is prone to form there. Compared with the failure heart, non-physiological shear stress (NPSS)-caused platelet activation is the main reason for thrombus formation within VAD. The narrow zones (top clearance and secondary flow passage) within VAD have a high incidence of thrombus generation. In VAD patients, the LV volume has an important impact on thrombosis probability within failure heart, in which the larger size of the LV volume is, the higher risk of thrombosis will be. The size of LV volume has little effect on the thrombosis formation probability of VAD, where the NPSS plays the leading role in thrombosis formation. The finding of this study can be utilized to guild the clinical treatment and VAD structure optimization design for reducing the thrombosis risk.
