Development of a paracorporeal left ventricular assist pump system: an experimental study

Experiments were designed to compare the hemodynamic performance and metabolic effect of a paracorporeal left ventricular assist pump system (PLVAPS) with those of intra-aortic balloon pumping (IABP) in a series of 35 dogs with and without myocardial infarction (MI). The animals were subjected to a three-hour period of pumping seven days after implantation of catheters and loose left anterior descending coronary (LAD) snares. MI was produced by closed-chest snaring of the LAD 13 hours before the onset of pumping. Measurements in addition to blood chemistry included aortic, pulmonary, atrial and ventricular pressures, ECG, cardiac index, left ventricular stroke work index (LVSWI) and endocardial viability ratio (EVR). The hemodynamic effects of PLVAPS assistance in normal control dogs and dogs with induced MI closely paralleled those observed with IABP. Both assist devices significantly increased systemic perfusion, decreased LVSWI, and increased EVR by reducing the oxygen demand. Infarct sizes were not significantly reduced with the two modes of pumping. The parameters measured indicate that in our experimental infarct model there is no significant differences between PLVAPS and IABP.