THROMBOLYSIS FOR ACUTE MYOCARDIAL-INFARCTION

Thrombolytic therapy has been a major advance in the management of acu te myocardial infarction. Unfortunately, it continues to be underused or is administered later than is optimal. Thrombolytic therapy works b y lysing infarct artery thrombi and achieving reperfusion, thereby red ucing infarct size, preserving left ventricular function, and improvin g survival. The most effective thrombolytic regimens achieve angiograp hic epicardial infarct-artery patency in only approximate to 50% of pa tients within 90 minutes. Bleeding requiring transfusion occurs in app roximate to 5% of patients and stroke in approximate to 1.8% with thes e regimens, which include adjunctive aspirin and intravenous heparin. There are several ways in which reperfusion rates and thus patient out comes might be improved, such as different dosing regimens of establis hed agents; combinations of different agents; improved adjunctive ther apy such as direct antithrombin agents, low-molecular-weight heparin, or glycoprotein IIb/IIIa receptor antagonists; or the development of n ovel thrombolytic agents with enhanced fibrin specificity, resistance to native inhibitors, or prolonged half-lives allowing bolus administr ation. All of these strategies are being tested in clinical trials. Th e best approach currently is to administer thrombolytic therapy as soo n as possible to all patients without contraindications who present wi thin 12 hours of symptom onset and have ST-segment elevation on the EC G or new-onset left bundle-branch block, unless an alternative reperfu sion strategy is planned.