In vivo evaluation of an implantable magnetic suspending left ventricular assist device.

PURPOSE: The CH-VAD is an implantable, fully magnetically suspended ventricular assist device developed by the China Heart Biomedical Corporation (Suzhou, China) for full cardiac support. This study was performed to evaluate the reliability, hemocompatibility and end-organ effects of CH-VAD in a 35-day animal model trial.

METHODS

The pump was implanted in 6 sheep. The pump inflow was inserted into the left ventricle and the outflow graft was anastomosed to the descending aorta. Data on pump function and the health condition of the animals, including hematologic and biochemical tests, were collected during the study period. When each study was determined to termination, the sheep were humanely euthanized and the end organs were examined macroscopically and histopathologically. Hemolysis was evaluated based on the amount of free hemoglobin in the plasma.

RESULTS

Except for one device that stopped operation on postoperative day 25 because of thrombus formation, the devices functioned normally until the scheduled termination. Gross examination of the pump interiors, inflow and outflow, and of the arterial anastomosis sites showed no significant abnormalities. Hematologic and biochemical test results were within normal limits during the study period. Macroscopic and histopathologic examinations of the explanted organs revealed no evidence of ischemia or infarction associated with the device implantation, except for small foci of infarction in the kidneys of two sheep. The free hemoglobin level in plasma peaked at 9.5 mg/dl on postoperative day 5.

CONCLUSIONS

The CH-VAD system demonstrated promising reliability and blood-handling characteristics without obvious damage to end organs during a 35-day implantation in sheep.