Unstable angina accounts for more than 1 million hospital admissions annually1; 6 to 8 percent of patients with this condition have nonfatal myocardial infarction or die within the first year after diagnosis.2,3 Various definitions of unstable angina have been proposed, but in 1989, Braunwald devised a classification system to ensure uniformity of categorization, as well as diagnostic and prognostic information.4 This system is used to classify angina according to the severity of the clinical manifestation, defined as acute angina while at rest (within the 48 hours before presentation), subacute angina while at rest (within the previous month but . . .