Novel Connecting Conduit-Free and Bypass Circuit-Less Mini LVADs for Reducing Thrombosis Risk

All existing left ventricular assist devices(LVADs) need inlet and outlet connecting conduits 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 disturbance to natural circulation, as well as additional 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 53 g has a length of 115 mm and its largest O.D. is 13 mm. The motor is 60 mm long and the pump 55 mm. In both sides of motor, special designed needle bearings are devised and a purge system keeps the motor together with bearings working in saline. The device is inserted into the ventricle by trans-apex and then into the aorta by cross-valve. It is used for recovery therapy. The bearing-less valvo-pump has an outer diameter of 21 mm, 23 mm or 25 mm for patients with different body weights. The weight of the device is 27 g, 31 g or 40 g respectively. Used for destination therapy it can be easily sewed onto the aortic valve annulus, delivers blood from ventricle to aorta directly. These two novel mini LVADs may reduce thrombosis risk in clinical applications.