ABSTRACT
BACKGROUND: Current guidelines suggest treating acute coronary syndromes (unstable angina, non-Q-wave myocardial infarction) with either coronary angiography followed by revascularization or conservative treatment with symptom-driven angiography. The goal of this study was to determine which approach is superior.
POPULATION STUDIED: The investigators enrolled 1810 patients presenting with acute coronary syndromes. Patients were eligible for the study if they had suspected cardiac chest pain. They also had to have evidence of coronary artery disease with at least 1 of following indicators of an acute coronary syndrome: evidence of ischemia on electrocardiogram, pathological Q waves suggesting previous myocardial infarction, or angiographic evidence of coronary artery disease on previous angiography. Patients were excluded if they had evidence of evolving myocardial infarction, myocardial infarction within the previous month, percutaneous intervention during the preceding 12 months, or coronary bypass at any time.
STUDY DESIGN AND VALIDITY: This study was a randomized, multicenter controlled trial. Patients were randomized to receive either conservative treatment with antianginal and antithrombotic treatment (n=915) or immediate intervention with catheterization and further intervention at the discretion of the treating cardiologist (n=895). The conservative treatment group received antianginal treatment, antithrombotic medications (aspirin and enoxaparin), and beta-blockers if not contraindicated. Additional treatments with glycoprotein IIb/IIIa inhibitors or other antiplatelet therapy were left to the discretion of the treating physician. The intervention group also received antianginal therapy and antithrombotic agents, but also received cardiac angiograms within 72 hours of presentation. Based on the findings at catheterization, additional intervention was left to the discretion of the treating cardiologist (stents, angioplasty, bypass, or medical management). Patient status was monitored for a median follow-up period of 2 years.
OUTCOMES MEASURED: The primary outcomes measured were combined rate of death, myocardial infarction, or refractory angina.
RESULTS: Of the 915 patients initially assigned to conservative treatment, 142 went on to have angiograms due to persistent symptoms. Ninety-two of these patients underwent angioplasty. Of patients in the intervention group, 311 had angioplasty, 184 had bypass surgery, and 388 were not deemed to need any surgical intervention and were treated medically. No difference was noted between the groups in overall mortality (approximately 11% in either group) or subsequent acute myocardial infarction. Patients in the intervention group were less likely to have refractory angina within 4 months (4.3% vs 9.3%, NNT=20) and within 1 year (6.5% vs 11.6%, NNT=20).
Conservative treatment was nearly as effective as immediate catheterization and surgical intervention in patients presenting with acute coronary syndrome. No difference was noted in the risk of death or myocardial infarction in either group. Patients were less likely to experience refractory angina when evaluated at 4 months and after 1 year when treated aggressively (numbers needed to treat [NNT]=20). Saving 1 readmission for refractory angina at the cost of performing 19 interventions that have no effect on the patient may not be reasonable.