COMPARISON OF THE EFFECTS OF STREPTOKINASE AND TISSUE PLASMINOGEN-ACTIVATOR ON REGIONAL WALL MOTION AFTER 1ST MYOCARDIAL-INFARCTION - ANALYSIS BY THE CENTERLINE METHOD WITH CORRECTION FOR AREA AT RISK

In a trial of streptokinase versus recombinant tissue-type plasminogen activator (rt-PA) for a first myocardial infarction, 270 patients were randomized. Regional left ventricular function was assessed in 214 patients at 3 weeks. The infarct-related artery was the left anterior descending artery in 78 patients, the right coronary artery in 122 and a dominant left circumflex artery in 14. Analysis was by the centerline method with a novel correction for the area of myocardium at risk, whereby the search region was determined by the anatomic distribution of the infarct-related artery. Infarct-artery patency at 3 weeks was 73% in the streptokinase group and 71% in the rt-PA group. Global left ventricular function did not differ between the two groups. Mean chord motion (+/- SD) in the most hypokinetic half of the defined search region was similar in the streptokinase and rt-PA groups (-2.4 +/- 1.5 versus -2.3 +/- 1.3, p = 0.63). There were no differences in hyperkinesia of the noninfarct zone. Compared with conventional centerline analysis, regional wall motion in the defined area at risk was significantly more abnormal. The two methods correlated strongly, however (r = 0.99, p < 0.0001), and both methods produced similar overall results. Patients with a patent infarct-related artery and those with an occluded artery at the time of catheterization had similar levels of global function (ejection fraction 58 +/- 12% versus 57 +/- 12%, p = 0.58). Regional function was also similar in patients with a patent and an occluded infarct-related artery on univariate analysis (-2.3 +/- 1.5 versus -2.6 +/- 1.1 SD, p = 0.14), but multivariate analysis correcting for variation due to infarct site showed that a patent infarct artery was associated with improved regional function (p = 0.007). Streptokinase and rt-PA in the doses given have similar effects on global and regional left ventricular function measured 3 weeks after a first myocardial infarction.