In vitro and in vivo Evaluation of TONGXIN LVAD

摘要

Background: Tongxin left ventricular assist device(LVAD), an implantable magnetic suspending VAD developed in China Heart Biomedical Incorporation aiming for clinical use, weighs about 350 g and can deliver 6 L/min for pressures of 145 mmHg at 2500 rpm. Objective: This study aims to investigate the implantation possibility, hemolysis and hemocompatibility of the LVAD before clinic use. Methods: The tests of implantation possibility, hemolysis and hemocompatibility to the LVAD were completed by fitting study, hemolysis test and in vivo experiments respectively. Meanwhile the hemolysis was evaluated by the amount of free hemoglobin in plasma and studied using the normalized index of hemolysis(NIH). Results: The fitting study showed that the blood pump could be implanted in the sheep heart chambers without squeezing the surrounding organs by comparing the preoperative and the postoperative chest X-ray. The NIH value of Tongxin LVAD was(0.00750±0017) g/100 L in vitro hemolysis test. Two sheep in vivo experiments showed the hemolysis in vivo was below 7.5 mg/dL. Hematologic and biochemical test results were within normal limits during the study period. There were no significant complications. Postmortem examination of the explanted organs revealed no evidence of microemboli, ischemia or infarction. The pump's inflow and outflow conduits were free of thrombus. Conclusion:These results indicated that the implantable magnetic suspending LVAD showed exceptional implantation possibility, hemolysis and hemocompatibility, which are crucial to the clinical success of this implantable LVAD.