[Surgical revascularization in patients with acute myocardial infarction]

This retrospective study was done to assess the results of emergency revascularization in patients with acute myocardial infarction. In addition, the influence of the mode of reperfusion was investigated in terms of morbidity and mortality. Between January 1987 and May 1992, 75 consecutive patients with acute coronary occlusion (in 87% PTCA-failure) received one of two different reperfusion protocols during emergency aortocoronary bypass operation. In 36 patients, the reperfusate was normal blood given at systemic pressure (uncontrolled reperfusion); in 39 patients, the ischemic area was initially reperfused for 20 minutes with a blood cardioplegic solution (substrate-enriched, hyperosmolar, hypocalcemic, alkalotic, diltiazem-enriched) given at 37 degrees C and at a perfusion pressure of 50 mmHg. Thereafter, the heart was kept in the beating empty state for 30 minutes before extra-corporeal circulation was discontinued (controlled reperfusion). Regional contractility (echocardiography, radionuclide ventriculography), electrocardiogram (ECG), release of creatine kinase and MB-isoenzyme of creatine kinase as well as hospital mortality were assessed. Quantification of regional contractility was done with a scoring system from 0 (normokinesis) to 4 (dyskinesis). Data are expressed as mean +/- standard error of the mean (SEM). Both groups were well matched for age, sex, and the distribution of the occluded artery. In the controlled reperfusion group, there was a higher incidence of additional significant stenosis (2.2 +/- 0.1 vs 1.7 +/- 0.1) and cardiogenic shock (36% vs 17%). Furthermore, the interval between coronary occlusion and reperfusion was longer in the controlled reperfusion group (4.1 +/- 0.3 vs 3.3 +/- 0.3 hrs; p > 0.05). Regional contractility returned to normal after controlled reperfusion (score 0.8 +/- 0.2; normokinesis = 0, slight hypokinesis = 1). In contrast, regional contractility remained depressed severely after uncontrolled reperfusion with normal blood (score 1.5 +/- 0.3; p < 0.05). Enzyme release and ECG-changes were similar in both groups postoperatively. While only 2 of 39 patients died in the controlled reperfusion group (5.1%), mortality increased to 11.1% (4/36) if normal blood is used as the primary reperfusate. Our data show, that the surgical revascularization during acute myocardial infarction can be performed with acceptable mortality and morbidity rates. Further improvement of the results can be obtained if controlled regional reperfusion for the previously ischemic area is used.