The tip structure of LVAD inflow cannula is one of major factors to lead adverse events such as thrombosis and suction leading to obstruction. In this research, four kinds of tips that had been used in inflow cannulas were selected and designed. The flow field of the four inflow cannulas inserted into the apex of left ventricle (LV) was numerically computed by computational fluid dynamics. The flow behavior was analyzed in order to compare the blood compatibility and suction in left ventricle and cannulas after the inflow cannulas with different tips were inserted to the apex of LV. The results showed that the cannula tip structure affected the LVAD performance. Among these four cannulas, the trumpet-tipped inflow cannula owned the best performance in smooth flow velocity distribution without backflow or low-velocity flow so that it was the best in blood compatibility. Nevertheless, the caged tipped cannula was the worst in blood compatibility. And the blunt-tipped and beveled tipped inflow cannulas may obstruct more easily than trumpet and caged tipped inflow cannulas because of their shape. The study indicated that the trumpet tip was the most preferable for the inflow cannula of long-term LVAD. 1. Introduction LVADs have been widely applied to assist the circulation of heart failure (HF) patients. Some LVADs can prolong HF patients’ lives for more than two years [1–5]. Now, most LVADs are equipped with complete accessories such as designed inflow and outflow cannulas to ensure that the LVADs can work safely and longer. The inflow cannula is the connection between left ventricle and LVAD. The inflow cannulas are mainly made of good blood compatibility materials such as titanium alloy, silicon rubber, or polythene. The shapes of inflow cannulas include blunt, beveled, caged, trumpet, and beak [6]. For example, the inflow cannula of Berlin Heart INCOR is made of silicon rubber with beak-shaped tip [7, 8]. And the inflow cannula of Debakey LVAD is made of titanium alloy with trumpet shaped tip [9, 10]. The tip shape is a critical factor to fluid dynamic performance. The flow field and stress distribution in left ventricle and cannulas depend on the inflow cannulas tip structure at a certain flow rate and operative procedures such as insertion depth and insertion angle. Different tip structures of inflow cannulas can cause various degree of thrombosis and suction leading to obstruction that may further influence the LVAD’s service life and the survival of the patients [11, 12]. Thrombosis is mainly caused by static and/or vortical flow in the inflow
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