- Recent (< 6 months) myocardial infarction, unstable angina, CABG or stent placement in the last 2 years, difficult-to-control congestive heart failure, uncontrolled hypertension (systolic blood pressure > 160 mm or a diastolic BP > 110 mm under normal conditions and while on appropriate anti-hypertensive medications), or difficult- to-control cardiac arrhythmias