Acute coronary syndromes - An update. Part II: Coronary revascularization and risk stratification

Coronary Revascularization: PTCA in patients with refractory unstable angin a is associated with a substantial risk of the following complications: dea th, myocardial infarction, need for emergency surgery, and restenosis. The introduction of intracoronary stents, however, has improved both short-term and long-term outcomes. The newer adjunctive pharmacologic therapies enhan ce even further the benefits associated with the use of stents. The decisio n regarding the specific revascularization procedure to be used (e.g., CABG , PTCA, stent placement, or atherectomy) is based on the coronary anatomy, the left ventricular function, the experience of the medical and surgical p ersonnel, the presence or absence of coexisting illnesses, and the preferen ces of both the patient and the physician. Risk Stratification: Among patients with unstable angina or non-Q-wave myoc ardial infarction, there is an increased risk of death within 6 weeks in th ose with elevated troponin I levels a nd the risk of death continues to inc rease as the troponin level increases. Reversible ST segment depression is associated with an increase by a factor of 3-6 in the likelihood of death, myocardial infarction, ischemia at rest, or provocable ischemia during a te st to stratify risk, Exercise or pharmacologic stress testing provides im p orta nt information a bout a patient's risk. Although the conditions of the majority of patients with unstable angina wi ll stabilize with effective antiischemic medications, approximately 50-60% of such patients will require coronary angiography and revascularization be cause of the "failure" of medical therapy. High-risk patients are those who have had angina at rest, prolonged angina, or persistent angina with dynam ic ST segment changes or hemodynamic instability, and they urgently require simultaneous invasive evaluation and treatment. Medical thera py should be adjusted rapidly to relieve manifestations of ischemia and should include antiplatelet therapy (aspirin, or ticlopidine or clopidogrel if aspirin is contraindicated), antithrombotic therapy (unfractionated heparin or low-mol ecular-weight heparin), beta-blockers, nitrates, and possibly calcium-chann el blockers. Early administration of glycoprotein IIb/IIIa inhibitors may b e particularly important, especially in high-risk patients with positive tr oponin tests or those in whom implantation of coronary stents is anticipate d.