Left ventricular assistance using a catheter-mounted coaxial flow pump (Hemopump) in a canine model of regional myocardial ischaemia

The global and regional effects of left ventricular circulatory assistance were examined in dogs during acute myocardial infarction using a new coaxial flow device (Hemopump). In 12 dogs the left anterior descending coronary artery was occluded for 4 h and subsequently reperfused for 12 h. In six dogs, left ventricular assistance was started 90 min after coronary artery occlusion and maintained for several hours; six control animals received no circulatory support. Survival rate in the animals receiving mechanical support was 100% vs 0% in the control group. The Hemopump reduced left ventricular stroke work up to 80% and maintained blood flows to the brain, kidneys, liver and intestine throughout the experiment. Infarct size, expressed as a percentage of the left ventricle, however, was not mod(fied (12% in supported animals vs 13% in control dogs). Side effects of the coaxialfiow pump were thrombocytopaenia, occurring in all six dogs, and haemolysis, which was demonstrated in one animal. It was concluded that the Hemopump provides effective global and regional circulatory support in a canine model of severe cardiogenic shock. However, the value of left ventricular support to modify infarct size could not be demonstrated in this experimental model.