DEVELOPMENT OF AN IMPLANTABLE CENTRIFUGAL BLOOD PUMP FOR CIRCULATORY ASSIST

An implantable centrifugal pump (ICP) for prolonged circulatory assist has been developed, at 320 mi and 830 g. A central balancing hole was made in its impeller for better antithrombogenicity. Waterproofing an d histocompatibility were supported by a silicone seal and a casing ma de of titanium and acrylic resin. Overall efficiency was 30% and norma lized index of homolysis was 0.003 mg/dl, the same value as the BP-80, at a flow rate of 5 L/min and a head of 100 mmHg. Antithrombogenicity and hemolytic properties of the ICP were investigated in paracorporea l implantation in three goats (61-71 kg). Exothermicity, anatomic fit, and water tightness of the ICP were evaluated in intrathoracic implan tation in an adult goat (66 kg). The ICP could run paracorporeally for 50, 200, and 381 days. There was no thrombus in the ICP after 381 day s' pumping, and the ICP could run in the chest cavity for 40 days. The temperature of the motor rose 1.8 +/- 0.3 degrees C from that of the pleura. Moisture content of the seal remained normal. The ICP was comp letely covered with smooth fibrous tissue. Although a small area of at electasis was found in the lingula, neither lung adhesion nor necrosis of the chest wall was observed. The ICP has satisfactory antithrombog enicity, hemolytic property, water tightness, anatomic fit, and exothe rmicity for use as an implantable circulatory assist device.