Myocardial protection by a left ventricular assist device during reperfusion following acute coronary occlusion.

To evaluate the effects of a left ventricular assist device (LVAD) during the reperfusion period following acute coronary occlusion, sixteen mongrel dog hearts were subjected to 1 hour's occlusion of the circumflex coronary artery and then reperfused for 6 hours. In seven control dogs (control group), the hearts were reperfused without any support. In nine LVAD dogs (LVAD group), however, the left ventricles were supported by the application of a pneumatic driven diaphragm-type pump for 5 hours and then reperfused for another hour without any device. Triphenyltetrazolium chloride was used to determine the extent of infarction. The results showed a significant reduction in the area of infarct (AI) as a percentage of the area at risk (AR) in the LVAD group compared with the control group, the AI/AR being 22.3 per cent for the control group versus 4.8 per cent for the LVAD group (p less than 0.05). The cardiac output was also significantly higher in the LVAD group compared with the control group. The per cent systolic shortening in the ischemic region of the LVAD group showed a significantly better recovery, being 75.8 per cent for the LVAD group versus 24.4 per cent for the control group (p less than 0.01). It was concluded that the application of a LVAD during reperfusion after 1 hour's coronary occlusion results in a significant reduction of infarct size and provides improvement in both regional and global cardiac function.