Investigation of a new prototype of multi-balloons LVAD using FSI

This research aims at three-dimensional modeling and simulation of a new system of specific cardiac assist device using fluid–structure interaction method. This device consists of two sets of double semi-cylindrical balloons implanted around ascending aorta which can help the blood flow to be pumped with more strength into the blood circulatory system by their inflations and deflations. These two sets are performed with a delay in time to pump the blood in a more continues and peristaltic way. The effect of this assist device on the hemodynamic pattern like blood velocity field, von Mises stress, outlet flows in descending aorta, brachiocephalic, carotid, subclavian and coronary arteries and aortic valve force are investigated. Results indicate that the assist device significantly affects the blood velocity and pressure within inflation/deflation times. The von Mises stress at the time of maximum contraction of first set of balloons in case of using assist device is 18 times that of the case without assist device. The maximum stress decreases 16% if we use two sets of balloons instead of implanting only one set of balloons in ascending aorta. Furthermore, the outer curvature of ascending aorta experiences the higher von Mises stress (2 MPa) compared to inner curvature (0.32 MPa) at the time of maximum contraction and occurs near the entrance of secondary balloons. The results also show the maximum aortic force of 3.4 and 4.2 N for the assist device with two and one sets/set of balloons, respectively, in times of balloons’ inflation/deflation (19% reduction with two sets of balloons). The outcome of outlet flows reveals that the inflation of the first balloons has the highest effect on the outflows at right coronary artery (increases the blood flow 10.9 times) compared to the other ones. At the second peak flow associated with contraction of secondary set of balloons, the most affected outlets are associated with descending aorta and brachiocephalic arteries (increases the blood flow 11.2 times).