Thrombolytic Therapy in Acute Myocardial Infarction: A Review with Current Recommendations

Thrombolytic therapy has clearly become an established therapeutic modality to treat patients with acute myocardial infarction. Since there is no ideal agent at this time, we must evaluate the advantages and disadvantages of current therapy based on major clinical studies. Thrombolysis is the body's natural response to dissolving clots after they have served their purpose. Thrombolytic agents accelerate fibrinolysis by overwhelming the system. There are 4 thrombolytic agents currently available: streptokinase urokinase, anistreplase (APSAC), and rt-PA. Tissue plasminogen activator is a naturally occurring protein that can be created with genetic recombinant technology (rt-PA). It establishes higher patency rates (70–90%) than the other available thrombolytic agents. Recently published results of accelerated rt-PA infusion during acute myocardial infarction demonstrate that the infarct-related artery seems to open more quickly and provide greater blood flow. The use of intravenous heparin as adjunctive therapy along with aspirin seems to maintain patency at comparable levels to streptokinase. Not only is mortality reduced in the accelerated rt-PA group, but complications from myocardial infarction such as arrhythmia and heart failure are significantly reduced. rt-PA remains the drug of choice in the hypotensive patient and, because of potential allergy, in patients with previous exposure to streptokinase. Percutaneous transluminal coronary angioplasty is frequently needed to improve long-term patency and reduce ischemic episodes. Recent studies show that it may provide some advantage over thrombolytic therapy, because the artery can be opened faster, with higher flow rates.