Coronary angiographic findings do not predict clinical outcome in patients with unstable angina

Objectives. The presence of thrombus formation and type of coronary artery lesion were determined in patients with unstable angina and correlated with the angiographic findings and clinical outcome. Background. Some previous studies have suggested that thrombus formation and lesions are predictive of the angiographic and clinical findings. This was evaluated in a retrospective analysis of 159 patients participating in the placebo controlled Unstable Angina Study Using Eminase (UNASEM) trial on the effect of thrombolysis in unstable angina. Methods. Patients without a previous myocardial infarction who presented with a typical history of unstable angina in the presence of abnormal findings on the electrocardiogram indicative of ischemia were included in the study. After baseline angiography, study medication (anistreplase or placebo) was given to 126 of 159 patients. Thirty-three patients did not receive medication because of significant main stem disease or normal coronary arteries or for other reasons. Angiography was repeated after 12 to 28 h. Results. Quantitative angiography showed a significant decrease in diameter stenosis in the anistreplase-treated group compared with the placebo treated group (decrease 11% vs. 3%, p = 0.008). No differences in clinical outcome were found when thrombolytic treatment was compared with placebo (p = 0.98). Neither the presence nor absence of thrombus formation (p 0.98) nor the type of lesion (p = 0.96) was related to the changes in diameter stenosis or to clinical outcome (p = 0.90 and p = 0.77, respectively). The power of these analyses to detect a 20% difference varied between 56% and 74%. Conclusions. In this selected group of patients with unstable angina, type of coronary artery lesion and the presence or absence of thrombus formation does not predict clinical outcome.