RESUMO
BACKGROUND: Thrombolytic therapy improves left ventricular ejection fraction and survival. The study was undertaken to evaluate the effects of intraaortic balloon pump used in conjunction with reperfusion in reducing infarct size. METHODS: Twenty-two dogs were subjected to proximal left anterior descending coronary artery occlusion. In group 1 (n = 7) occlusion lasted for 6 hours. In group 2 (n = 6) 2 hours of occlusion was followed by reperfusion. In group 3 (n = 9) after 2 hours of occlusion the dogs were assisted with the intraaortic balloon pump throughout the 4 hours of reperfusion. At the end of 6 hours the infarcted myocardium of the left ventricle was determined and expressed as percentage of the myocardium at risk. RESULTS: In group 1, the infarcted myocardium was 79.3 +/- 9.9% of the myocardium at risk, in group 2, 59.0 +/- 19.9% (p < 0.05 versus group 1), and in group 3, 37.1 +/- 16.7% (p < 0.001 versus group 1 and p < 0.05 versus group 2). Endocardial viability ratio was increased by the intraaortic balloon pump; in group 1 it was 1.02 +/- 0.14, in group 2, 1.25 +/- 0.24, and in group 3, 1.47 +/- 0.31 (p < 0.001 versus group 1 and p < 0.02 versus group 2). CONCLUSIONS: Reperfusion and intraaortic balloon pump increased salvage of the ischemic myocardium over that achieved by reperfusion alone in a canine occlusion-reperfusion model.