Interventions in acute myocardial infarction.

Results of multiple studies have amply verified the benefit of urgent coronary revascularization for patients who have acute myocardial infarction (MI). Currently, intravenous thrombolytic therapy is the treatment of choice for many patients, especially those 75 years old or younger who present within 6 hours of symptom onset and who are without contraindications to thrombolytic therapy. Some patients treated within 6-24 hours of symptom onset may also benefit, but this remains unproven. The thrombolytic agents currently in use or being extensively evaluated include streptokinase, urokinase, tissue-type plasminogen activator (t-PA), anisoylated plasminogen streptokinase activator complex (APSAC or anistreplase), and single-chain urokinase-type plasminogen activator (scu-PA). The agent t-PA has the potential advantage of being clot selective and, thereby, relatively fibrinogen sparing, and its efficacy in terms of restoration of vessel patency is less dependent on the time of administration as compared with that of streptokinase and urokinase. It is not yet known whether this will translate into improved patient survival as compared with that achieved by the less-expensive agents streptokinase and APSAC. Treatment regimens of combination thrombolytic agents have been developed, but the optimal combinations have not yet been determined. Patients who are in cardiogenic shock and those in whom thrombolytic therapy is contraindicated can probably benefit from angioplasty or bypass surgery. Results of several studies have suggested that immediate angioplasty after successful thrombolysis is not beneficial; however, the potential benefit of angioplasty or bypass surgery for failed thrombolytic therapy is yet to be evaluated. Although many advances have been made, further research is clearly needed in the area of reperfusion.