Effect of spontaneous reperfusion on myocardial infarct size

Effects of early thrombolytic therapy (anistreplase versus streptokinase) on enzymatic and electrocardiographic infarct size in acute myocardial infarction. TEAM-2 Investigators

The effects of thrombolytic therapy on enzymatic and electrocardiographic indexes of myocardial infarction were examined in 370 patients who were enrolled within 4 hours of onset of symptoms and were randomized to blinded therapy with intravenous anistreplase (30 U/5 min, n = 188) or streptokinase (1.5 million IU/1 hour, n = 182). Creatine kinase and its MB isoenzyme were initially measured every 4 to 6 hours, and lactic dehydrogenase (LDH) and its cardiac isoenzyme (LDH-1) every 8 to 12 hours. Electrocardiograms were obtained before, and at 90 minutes and 8 hours after starting thrombolysis, and on discharge. Enzymatic and electrocardiographic measures of infarction were compared between drug treatment and patency groups. Early patency was associated with significant reductions in peak values for each of 4 cardiac enzymes (averaging 21 to 25%, p less than 0.01 to 0.001), even though later rescue procedures were often used in the nonpatient group; times to peaks were also reduced for 3 of the enzymes. Treatment with anistreplase was associated with enzymatic peaks that tended to be lower than with streptokinase (6 to 16%), approaching or reaching significance for LDH (p less than or equal to 0.07) and LDH-1 (p less than or equal to 0.04); times to peaks were similar. Early patency favorably affected electrocardiographic indexes. Summed ST-segment elevations resolved more rapidly (p less than or equal to 0.04), summed Q-wave amplitude was reduced by 32% (p less than or equal to 0.01), and total QRS infarct score on discharge was 22% less (p less than or equal to 0.006) in those achieving early patency. Small differences in electrocardiographic indexes between the 2 drug treatment groups were not significant. These results support use of early reperfusion to reduce infarct size in acute myocardial infarction with administration of streptokinase and anistreplase.

Effect of reperfusion on electrocardiographic and enzymatic infarct size: results of a randomized multicenter study of intravenous anisoylated plasminogen streptokinase activator complex (APSAC) versus intracoronary streptokinase in acute myocardial infarction

The effect of early coronary artery reperfusion on ECG and enzymatic parameters was examined in 240 patients with acute myocardial infarction. These patients had participated in a randomized trial comparing intravenous anisoylated plasminogen streptokinase activator complex (APSAC) (n = 123) and intracoronary streptokinase (n = 117) therapy. Reperfusion occurred in 59 of 115 (51%) patients receiving APSAC and 67 of 111 (60%) patients receiving streptokinase (p = NS). There was greater early resolution of ST segment elevation in the reperfused than in the nonreperfused patients (p less than or equal to 0.003) and more rapid Q wave evolution (p less than or equal to 0.03). Sigma Q was lower in reperfused than in nonreperfused patients at 8 hours (1.41 +/- 1.18 versus 2.11 +/- 2.10 mV; p less than or equal to 0.05) and at 24 hours (1.43 +/- 1.25 mV versus 2.08 +/- 1.88 mV; p less than or equal to 0.02). Time to peak level was shorter in the reperfused patients for creatine kinase (CK) (10.7 +/- 5.5 hours versus 14.9 +/- 5.9 hours; p less than 0.0001) and lactic acid dehydrogenase (LDH) (29.6 +/- 13.6 hours versus 34.4 +/- 10.5 hours; less than or equal to 0.03) enzymes. Peak LDH-1 was lower in the reperfused group (274 +/- 149 U/L versus 341 +/- 173 U/L; p less than or equal to 0.04). Reperfusion at a mean of 3.9 hours after the onset of infarction was associated with more rapid resolution of ST segment elevation, faster Q wave evolution, smaller ECG infarct size, earlier cardiac enzyme release, and smaller enzymatic infarct size than later or no reperfusion.