Catheter-Mounted Microaxial Blood Pump Reduces Myocardial Infarct Size

NEW YORK (Reuters Health) – In sheep with induced MI, a miniaturized rotary blood pump mounted on a catheter and introduced via the femoral artery provides significant unloading of the left ventricle (LV) and leads to a reduction in infarct size.

Dr. Bart Meyns and colleagues from the Catholic University of Leuven in Belgium describe their studies with the Impella blood pump (Aachen, Germany) in the April 2nd issue of the Journal of the American College of Cardiology.

They induced myocardial infarction in 26 sheep by occluding two major branches of the left anterior descending coronary artery for 1 hour. This was followed by reperfusion for 2 hours. The animals were then assigned to one of four groups: full LV support with the Impella pump during ischemia and reperfusion, LV support with the pump during reperfusion only, partial LV support with the pump during reperfusion, or no support (control).

Dr. Meyns’ group observed a significant reduction in infarct size in all of the pump-supported groups. The group supported during both ischemia and reperfusion demonstrated the most explicit reduction in infarct size, they report.

“Pump support reduces myocardial oxygen consumption significantly, and this reduction correlates strongly with the reduction in infarct size,” according to the team.

During ischemia, the pump did not influence myocardial flow, but during reperfusion, the fully supported group showed significantly higher myocardial flow than the other groups. The Impella pump also produced significant hemodynamic effects, namely increased diastolic BP and decreased filling pressure.

This study suggests to Dr. Meyns and colleagues that “the clinical application of this pump is dual: the pump supports the failing circulation (treatment of shock patients), and early unloading results in a reduction of infarct size.”

J Am Coll Cardiol 2003;41:1087-1095.