804-4 A Randomized, Double-blind Trial of Streptokinase Versus Placebo for the Management of Unstable Angina and Non-Q-wave Myocardial Infarction in Patients with Previous Coronary Artery Bypass Surgery

This trial investigated the potential usefulness of thrombolysis in patients with previous coronary artery bypass surgery admired for unstable angina and non-Q-wave myocardial infarction, the rationale being more frequent non-Q-wave infarction in these patients and a high-fibrin content of older grafts. A total of 125 consecutive patients with symptoms evolving for less than 24 hr were randomized to intravenous streptokinase 1.5 million Units in 45 min, or to placebo. All patients received concomitant intravenous heparin, oral aspirin and standard anti-ischemic therapy. Mean age (62±9 yrs). sex (78% male). time of previous surgery (8±0.5 yrs), presence of a previous myocardial infarction (63%). prior medication including aspirin in 66%, an abnormal ECG at admission (79%) and time to treatment after the last ischemic episode (10±9 hr) were similar in the 2 study groups.Fatal and non-fatal myocardial infarctions in hospital occurred in 7 streptokinase (11.1%) and 3 placebo (4.8%) patients (relative risk 2.3, 95% confidence limits 0.62–8.48, p=0.19) and at 1 month in an additional 2 patients in each group. Refractory angina in hospital was observed in 12 (19.1%) streptokinase patients and 13 (20.9%) placebo patients. A revascularization procedure because of recurrent symptoms was required at 1 month in respectively 22 (34.9%) and 16 (25.8%) patients.ConclusionThe early cardiac event rate in unstable angina associated with previous bypass surgery is high. The nonsignificant excess in the risk of myocardial infarction with streptokinase in this population most likely to benefit, is similar to the excess reported in other populations of patients with unstable angina and non-a-wave myocardial infarction and supports the lack of benefit of thrombolysis in unstable angina