2. Unstable angina, defined as 1) Angina occurring at rest and prolonged, usually ≥ 10 minutes; 2) New onset angina of at least CCS classification III severity (i.e., marked limitation of ordinary physical activity - angina occurs on walking 1 to 2 blocks on the level and climbing 1 flight of stairs in normal conditions and at a normal pace); 3) no cardiac marker evidence of myocardial necrosis (e.g., negative troponin or CK-MB).