Improvement of Percutaneous Veno-Arterial Bypass System Toward Longer and More Physiological Assist

Abstract

Although percutaneous veno-arterial (VA) bypass is the most widely used assistance configuration, due to its ease of handling and low cost, its major disadvantages include the need for extensive anti-coagulation therapy and the early development of wet lung. To overcome these problems, we internally coated a Terumo percutaneous VA bypass system (EMERSAVE; Terumo, Tokyo, Japan) with heparin, and improved the durability of the oxygenator by heating around the gas outlet to prevent condensation. In an in vivo experiment, a sheep underwent left heart bypass (31/ min) with this system for 96 h, while activated coagulation time (ACT) was maintained at around 150 s. During bypass, the gas inlet pressure was maintained at the control level, and no significant deterioration in CO2 transfer was observed. Hematological measurements, of platelet count, the maximum aggregation ratio of platelets, antithrombin III (AT-III) level, and fibrinogen content, as well as measurement of pressure drop in the blood circuit, showed no significant changes. Macroscopically, only a slight amount of thrombus was detected, in the stagnation zone of the oxygenator, but there were no thrombi in the circuit or the centrifugal pump. Scanning electron microscope study revealed no significant platelet adhesion or deformity throughout the system. These improvements should lead to longer non-pulsatile VA bypass with fewer complications.