MedTech Mag-Lev, Single-use, Extracorporeal Magnetically Levitated Centrifugal Blood Pump for Mid-term Circulatory Support

• DOI: 10.1097/mat.0b013e31828a75e3
• Publication Date: 2013-05-03T13:17:55Z
• Authors: Eiki Nagaoka; Tatsuki Fujiwara; Takashi Kitao; Daisuke Sakota; Tadahiko Shinshi; Hirokuni Arai; Setsuo Takatani
• Keywords: Male; Magnetic Phenomena; Phosphorylcholine; Shock, Cardiogenic; Prosthesis Design; 3. Good health; Survival Rate; 03 medical and health sciences; 0302 clinical medicine; Coated Materials, Biocompatible; Animals; Methacrylates; Cattle; Heart-Assist Devices

Short- to mid-term extracorporeal ventricular assist devices (VADs) are recommended for critical cardiogenic shock patients. We have designed a preclinical, single-use MedTech Mag-Lev VAD for one-month extracorporeal use. The impeller-rotor of the pump was suspended by a two degree-of-freedom active magnetic bearing in a 300 μm fluid gap, where the computational fluid dynamics analysis predicted a secondary flow of about 400-500 ml/min at a pump speed of 1800-2200 rpm. Three eddy current sensors were employed to implement noise- and drift-free magnetic levitation. The pump components were injection molded using polycarbonate for smooth surfaces as well as improved reproducibility, followed by coating with a biocompatible 2-methacryloyl-oxyethyl phosphorylcholine polymer. Chronic animal experiments were performed in nine calves. Three of the nine calves were excluded from analysis for problems with the circuit. Five of the six (83.3%) completed the 60 day duration of the study, while one prematurely died of massive bleeding due to inflow port detachment. The pump did not stop due to magnetic-levitation malfunction. Neither pump thrombosis nor major organ infarction was observed at autopsy. In comparison to machined surfaces, the injection-molded pump surfaces were thrombus-free after 60 day implantation. This study demonstrates the feasibility of MedTech Mag-Lev VAD for 60 day circulatory support.