Use of risk stratification to identify patients with unstable angina likeliest to benefit from an invasive versus conservative management strategy

OBJECTIVES This study was designed to determine whether patient characteris tics collected at presentation can identify which patients benefit from imm ediate coronary angiography and revascularization. BACKGROUND Risk stratification may offer a method for identifying which pat ients with unstable angina or non-Q-wave myocardial infarction (NQMI) are l ikeliest to benefit from invasive management strategies. METHODS The analysis was based on data from a randomized controlled trial t hat enrolled 1,473 patients presenting with unstable angina or NQMI who wer e randomly assigned to an early invasive or early conservative (medical) ma nagement strategy. We constructed a risk-stratification score for each pati ent based on adjusted odds ratios for clinical variables likely to predict adverse outcomes. We stratified all trial subjects by their risk scores and studied the rates of death or myocardial infarction (MI) of the early inva sive management strategy in each stratum. RESULTS The final multivariate model included older age, ST segment depress ion on presentation, history of complicated angina before presentation, and elevation in baseline creatine kinase-IMB fraction. Although patients with a higher risk score had an increased rate of death or MI, within 42 days a nd 365 days (p < 0.001) in both management strategies, early invasive manag ement for patients in the high and very high risk categories was associated with a lower rate of death or MI within 42 days compared with conservative management. No such benefit was seen in patients in the larger group of pa tients in the very low, low or moderate risk categories (p = 0.03 for the i nteraction between risk category and management assignment). CONCLUSIONS Risk stratification may be an effective method for identifying those patients with unstable angina or NQMI most likely to benefit from ear ly invasive management. Selective use of early invasive management can have a substantial impact in reducing morbidity and mortality in higher risk pa tients, but may not be warranted in lower risk patients. (C) 2001 by the Am erican College of Cardiology.