Connecting conduit-free and bypass circuit-less mini LVADs eliminate the most likely sites of thrombosis

Abstract

All existing left ventricular assist devices (LVADs) need inlet and outlet connecting con-duits and the assist pumping blood flows through the bypass circuit from left ventricle to aorta. It will result in some most likely sites of thrombosis and brings about physiological dis-turbance to natural circulation, as well as addi-tional need for anatomic occupation in chest. The author developed a trans-apical and cross-valvular intra-ventricular axial pump and an aortic valvo- pump to solve these problems. The intra-ventricular pump weighing 53g has a length of 115mm and its largest O.D. is 13mm. The motor is 60mm long and the pump 55mm. In both sides of motor, specially designed needle bearings are devised and a purge system keeps the motor together with bearings working in sa-line. The device is inserted into the ventricle by trans-apex and then into the aorta by cross-valve. It is used for recovery therapy or bridge to transplantation. The bearing-less valvo-pumps have an outer diameter of 21mm, 23mm or 25mm for patients with different body weights. The weight of the devices is 27g, 31g or 40g respectively. Used for destination therapy it can be easily sewed onto the aortic valve annu-lus, delivers blood from ventricle to aorta di-rectly. These two novel mini LVADs may reduce thrombosis risk in clinical applications.