Lawrence A. Reduto

Intracoronary infusion of streptokinase in patients with acute myocardial infarction: Effects of reperfusion on left ventricular performance

Cardiac catheterization and coronary angiography were performed on hospital admission in 32 consecutive patients with acute myocardial infarction. Twenty-six patients had total occlusion of an infarct-related coronary artery and six had severe proximal stenosis with poor distal flow. In 18 of the 26 patients with total occlusion, intracoronary infusion of streptokinase resulted in reperfusion of the distal coronary artery. Seventeen of these 18 patients had severe coronary arterial stenosis at the site of the previous total occlusion. Hemodynamic indexes of left ventricular performance and ejection fraction determined by gated cardiac blood pool imaging did not change immediately after reperfusion (p [probability] = not significant [NS]). The mean (+/- standard deviation) left ventricular ejection fraction increased significantly (p = 0.007) from admission (44 +/- 15 percent) to hospital discharge (55 +/- 7 percent) in patients evidencing reperfusion of the occluded coronary artery. It did not change (p = NS) in this time span in the patients with severe stenosis alone, in those with total occlusion not demonstrating reperfusion after administration of streptokinase or in an additional 10 control patients with acute myocardial infarction not evaluated with coronary angiography. These data suggest that (1) coronary arterial thrombus is frequent in acute myocardial infarction and can be lysed by intracoronary streptokinase; (2) reperfusion with intracoronary streptokinase in acute myocardial infarction results in improved left ventricular performance between admission and hospital discharge.

Sustained improvement in left ventricular function and mortality by intracoronary streptokinase administration during evolving myocardial infarction.

One hundred eighty-eight patients with acute myocardial infarction were studied prospectively from August 1980 to September 1982. One hundred thirty-six of these patients were entered into a intracoronary streptokinase study after informed consent was obtained. The remaining 52 patients, who either met exclusion criteria for the study or refused to participate, served as a control group and were treated as those in the study group except that they did not undergo emergency cardiac catheterization. Left ventricular function was determined in both groups by gated radionuclide ejection fraction (EF) on admission to the hospital, at discharge, and 6 months after discharge. With successful reperfusion up to 18 hr after onset of chest pain, mean left ventricular function in the study group improved (EF 39 +/- 13% on admission and 46 +/- 12% at discharge; p less than .001). Mean EF in control patients and those not achieving reperfusion did not change from admission to discharge. Mean EF at 6 month follow-up was not significantly different than at discharge in the study group or the control group. Total cardiac mortality in the control group was 19% compared with 10% in the study group (p = .06, NS). When patients admitted in pulmonary edema or shock (Killip class III or IV) were excluded from both groups, total cardiac mortality in the study group was significantly lower (4%) compared with in the control group (12.5%, p less than .05. The administration of intracoronary streptokinase during evolving myocardial infarction up to 18 hr after onset of chest pain may result in decreased mortality and sustained improvement in left ventricular function.

Coronary artery reperfusion in acute myocardial infarction: Beneficial effects of intracoronary streptokinase on left ventricular salvage and performance

Coronary angiography was performed on hospital admission in 37 patients with acute myocardial infarction (AMI). Thirty patients had total occlusion of the infarct-related coronary artery and seven patients had severe proximal stenoses with poor distal flow. In 20 of 30 patients with total occlusion, intracoronary (IC) infusion of streptokinase (SK) resulted in reperfusion of the distal coronary artery. Left ventricular (LV) performance was assessed before coronary angiography and at discharge from the hospital by use of gated cardiac blood pool imaging techniques. In patients evidencing reperfusion of the infarct-related coronary artery, mean (+/- SD) left ventricular ejection fraction (LVEF) increased from admission through discharge (46% +/- 15% to 55% +/- 10%, p = 0.002). In contrast, LVEF did not change from admission through discharge in patients with severe proximal stenoses alone or in patients with total occlusion who did not demonstrate reperfusion following SK administration (47% +/- 17% vs 49% +/- 18%, p = ns). In an additional 14 control patients with AMI who were not evaluated with coronary angiography, LVEF did not change from admission through discharge (46% +/- 12% vs 48% +/- 14%, p = ns). Quantitative thallium-201 perfusion imaging demonstrated an increase (p less than 0.05) in thallium uptake in the infarct segment following coronary artery reperfusion. In contrast, thallium uptake did not change (p = ns) in the infarct segment in patients not evidencing angiographic coronary artery reperfusion. These data support the following : (1) Coronary artery thrombus occurs frequently in AMI and can be lysed by IC SK, and (2) reperfusion with IC SK in patients with evolving myocardial infarction results in myocardial salvage and improved LV performance through hospital discharge.

Beneficial effects of intracoronary thrombolysis up to eighteen hours after onset of pain in evolving myocardial infarction

Coronary arteriography and intracoronary streptokinase (STK) infusion were performed on 89 patients with evolving acute myocardial infarction (AMI). Ventricular function was followed in these patients during their hospitalization by gated radionuclide ventriculography. In 35 of these patients thallium imaging was performed on admission and 4 hours after reperfusion. An additional 30 patients with AMI who either met exclusion criteria for the STK protocol or refused study served as a control group. In patients admitted 0 to 6, 6 to 12, or 12 to 18 hours after onset of pain, there was no difference in change in left ventricular ejection fraction (LVEF) from admission to discharge, in percent of patients with total occlusion demonstrating reperfusion, or in percent of patients demonstrating a significant increase in LVEF. The average increase in LVEF from admission to discharge in patients reperfused ws 8% (40% +/- 14% to 48% +/- 13%, p less than 0.001). No change in LVEF was demonstrated in the control population or in patients in whom coronary reperfusion was unsuccessful. Reperfusion produced an increase in thallium uptake in the infarct-related myocardium that was accompanied by an improvement in regional function. Failure of reperfusion produced no change in either thallium uptake or regional function.

Role of coronary artery bypass surgery after intracoronary streptokinase infusion for myocardial infarction

Intracoronary streptokinase infusion has been shown to improve left ventricular function and reduce hospital mortality in patients with acute myocardial infarction. Adjuvant coronary artery bypass surgery is of value in many of these patients who have recurrent angina, circulatory instability, severe coronary artery occlusive disease, or a high risk of reinfarction. There is little, if any, evidence that immediate coronary artery bypass surgery affects the results adversely--either because of recent myocardial infarction or recent streptokinase infusion, and early operation appears to be a safe and worthwhile modality of treatment in this group of patients with myocardial infarction.