Numerical Study On The Thrombi Movement In The Aorta Caused By Lvad Cannula Anastomosis Location And The Area

The artificial heart used to treat end-stage heart failure, while thrombosis is a still the devastating complication. The traditional study focused on the fields of anticoagulant effect and optimize the design of blood pump, however, the incidence of stroke caused by thrombosis is still high. Optimize the hemodynamics in the aorta may avoid the thrombosis complications. The hemodynamics state has changed with the implant of artificial blood cannula outflow, but it is not clear that the outflow cannula location and area are hypothesized to affect the thrombi distribution in the aorta. The object of this article is clarify the thrombi movement from two aspect: anastomotic location and area, and through optimize the anastomotic location and area to decrease the probability of stroke.In order to exception the problem, this paper in aspects of 1and 2. Firstly, the models of different anastomotic location were achieved based on 3D reconstruction technique with the software of virtual surgery modeling, combination the discrete phase theory and finite element method, numerical simulation has going for the models under the anastomotic locations. Through analysis the hemodynamic parameters, and thrombi distribution numbers acquired to analyzed which enter into the arterial circulation from blood pump and intra-cardiac, the topic has discussed the influence to thrombi distribution from optimize the cannula locations. Secondly, the models of different cannula areas were build the based on 3D reconstruction and assistant software, thrombi is discrete phase and the blood is continuous phase were set, numerical simulation has going for the models, and research the influence of movement effect by anastomotic areas. The distribution of the different sources thrombi has been statistics, and the influence on the movements of thrombi in the aorta with the anastomosis areas has been discussed, 3 results are made as following.Firstly, The anastomotic location at the anterior type、between the anterior and lateral type、the lateral type, the probability of thrombi went into the brain vessel were 23.6%、33.8% and 36.7% respectively. In three models, the probability of thrombi went into the brain were 11.59%, 6% and 45.36% respectively which the thrombi formed in artifice heart. And the intra-cardiac thrombosis flow into the brain were 25.6%, 38% and 34.75%.Second of all, with the anastomosis areas gradually increasing, the probability of thrombi flow into the brain were 24.6%, 23.6%, 28.65% and 31.24% respectively. In four models, the probability of thrombi went into the brain were 8.5%, 11.6%, 27.36% and 43.24% respectively which the thrombi formed in artifice heart. And the intra-cardiac thrombosis flow into the brain were 21.19%, 25.59%, 28.86% and 30.69%.Third of all, there exist clockwise vortexes in the downstream position of anastomosis location. Compared with cardiac systolic, the vortexes location has move down in cardiac diastolic. In the different models, the vortexes location closer in brachiocephalic arteritis, the probability maybe great enter into brachiocephalic arteritis, and with the changed of anastomosis location, there exist some different of the change with vortex in the aorta arch. The probability may be higher of thrombi flow into left subclavian artery when the vortex more closely to left subclavian artery.Three conclusions are driven from the results: when the anastomotic location at the anterior type, the probability of thrombi entering into the brain is least; when the area equality with cannula, the probability is lowest; the hemodynamic has remark changed when optimize the anastomotic location and area, also influenced the movement of thrombi. It can through optimize the anastomotic patterns to decrease the probability of stroke.