ENHANCED PRESERVATION OF ACUTELY ISCHEMIC MYOCARDIUM WITH TRANSSEPTAL LEFT-VENTRICULAR ASSIST

Mechanical support for acute regional ischemia without hemodynamic collapse may be achieved percutaneously with an intraaortic balloon pump (IABP) or with transseptal left ventricular assist (TLVA) while awaiting revascularization. The relative benefits of these two percutaneous transfemoral techniques for the treatment of ischemia were compared in a representative animal model. During 90 minutes of regional coronary occlusion, four groups of 8 pigs were treated with either no support (control), IABF, TLVA, or both IABP and TLVA. Cardioplegic arrest for 30 minutes to simulate coronary grafting was followed by 180 minutes of global reperfusion on bypass. In all groups regional wall motion and interstitial pH in the area at risk were significantly depressed with ischemia, but wall motion fully recovered after reperfusion. However, histochemical staining of the area of necrosis/area at risk was significantly reduced with IABP versus control (20.2% versus 34.1%; p < 0.05) and further significantly reduced with TLVA and IABP + TT,VA (10.7% and 6.7% versus IABP alone; p < 0.05). We conclude that in supporting even a modest-sized myocardial region at risk (12% of the left ventricle) the area that went on to infarction was significantly reduced with the use of TLVA over IABP. Regional wall motion and myocardial pH measurements did not reflect this difference in the early reperfusion period. The benefit of TLVA over IABP during more extensive or prolonged ischemia may have real clinical significance.