Coronary artery flow ten weeks after myocardial infarction or unstable angina: effects of combined warfarin and aspirin therapy

Forty-three patients presenting with unstable angina or myocardial infarcti on were randomised double blind to warfarin [target international normalise d ratio (INR), 2.0 to 2.5] and aspirin (150 mg) daily or placebo plus aspir in (150 mg) daily. Coronary flow was assessed with the thrombolysis in myoc ardial infarction (TIMI) flow grade and corrected TIMI frame count (CTFC). Coronary artery flow was reduced (higher CTFC) at baseline in culprit arter ies (mean+/-SD, 37.1+/-15.4 frames) compared to nonculprit arteries (22.5+/ -6.7 frames, P<0.0001). In patients with a patent artery at follow-up, coro nary flow was unchanged after ten weeks of warfarin and aspirin (-2.0+/-19. 9 frames) or aspirin alone (3.8+/-10.4 frames, P=0.20). Patients randomised to aspirin alone were more likely to progress to total occlusion [aspirin, 7 of 19 (37%) vs. warfarin and aspirin, 1 of 24 (4%); P=0.01). Higher base line culprit artery CTFC was also associated with an increased risk of late occlusion [+10 frames; odds ratio (OR), 1.65; 95% CI, 1.01 to 2.33]. Coron ary flow remained impaired ten weeks after presentation with myocardial inf arction or unstable angina. Combination warfarin and aspirin therapy did no t improve flow in vessels that remained patent but did reduce the risk of p rogression to occlusion. (C) 1999 Elsevier Science Ireland Ltd. All nights reserved.