8/3/2023 0 Comments Fluid dynamics simulations![]() 27 employs conventional CFD extended with species transport of non-activated platelets, activated platelets and adenosine diphosphate (ADP) by means of additional convection diffusion equations. The thrombosis model presented in Taylor et al. 34 Despite being computationally cheap, the problem to obtain spatially resolved thrombus deposition within the domain remains, with recent approaches addressing this unmet need. This approach is similar to the hemolysis models existing in the literature. In consequence, each device exhibits a “thrombogenicity fingerprint” that can then be compared between different devices. Many studies in the past adopted the idea of a platelet activation state (PAS) 22, 26 that determines stress accumulation of platelet flow paths either through Eulerian or Lagrangian approaches. Several approaches that serve as good candidates for model development exist in the literature. Optimally, such models should be compatible with commercial CFD software to allow a wider adoption throughout the scientific and engineering community. In addition, thrombus models should be implementable within computational fluid dynamics (CFD) solvers, the gold-standard to determine blood flow characteristics in arbitrary geometries. Computational costs are the main challenge as the complex mechanisms of thrombus formation need to be combined with the intricate flow physics within rotary blood pumps comprising turbulent flow structures, complex geometries and high rotational speeds. ![]() 6 Considering model application in rotary blood pumps in particular poses additional requirements towards thrombosis models. 2Ĭomputational modeling can help to understand the underlying complexity of thrombus formation involving a wide range of mathematical models of thrombosis spanned across different spatial and temporal scales. 9 Ultimately the aforementioned factors enhance the hemostatic response by chronically activating platelets, the initiators of blood clots. 7 The causes for thrombus formation are multifactorial involving the molecular interplay of proteins and enzymes in the coagulation cascade, non-physiological blood flow conditions and interactions with foreign surfaces. 13, 15 Despite tremendous improvements in patient survival and overall quality of life over the last decades, one of the major device related complications is the formation of thrombi (blood clots) and the associated risk for cardioembolic stroke. Rotary blood pumps such as ventricular assist devices (VADs) and extracorporeal pumps are used in long-term and short-term mechanical circulatory support therapies for patients with acute and chronic heart failure. Relative comparisons of thrombus risk are possible even considering the intrinsic uncertainty in model parameters and operating conditions. The concentration of activated platelets can be used as a surrogate and computationally low-cost marker to determine potential risk regions of thrombus deposition in a blood pump. The calculation of thrombus risk requires an additional 10–20 core hours of computation time. ![]() Our model shows good correlation ( R 2 > 0.93) with clinical data and identifies the bearing and outlet stator region of the HeartMate II as the location most prone to thrombus formation. Furthermore, an operating point and model parameter sensitivity analysis was performed. ![]() The model was compared with existing clinical data on thrombus deposition within the HeartMate II. At the second stage, platelet activation by mechanical and chemical stimuli was determined through species transport with an Eulerian approach. The first stage involves the computation of velocity and pressure fields by computational fluid dynamic simulations. We used a two-stage approach to calculate thrombus risk. The aim of the study was to develop and test a computationally efficient model for thrombus risk prediction in rotary blood pumps. However, numerically cheap models able to predict localized thrombus risk in complex geometries are still lacking. Over the past years many computational models of thrombosis have been developed. This release includes significant GPU technology advancements, accurate hydrogen modeling from production to consumption, workflow, and automation improvements across the entire product line.Thrombosis ranks among the major complications in blood-carrying medical devices and a better understanding to influence the design related contribution to thrombosis is desirable. Pushing the envelope of performance, sustainability, and productivity for CFD simulations
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