Thrombolytic therapy offers the promise of major therapeutic intervention in many areas as well as in the treatment of patients with acute
myocardial infarction who present to the emergency department. Infusion of
tissue-type plasminogen activator (tPA) during field transport has been proven safe, but optimal methods for reliably diagnosing acute
myocardial infarction in the prehospital setting have yet to be delineated. A major advance would be achieved if thrombolysis were proven effective in preventing the progression of
unstable angina to actual
infarction. However, early studies have yielded contradictory results. The use of tPA in dissolving peripheral arterial clots appears very promising, but long-term limb survival has yet to be demonstrated. Unlike
heparin,
thrombolytic agents can also lyse clot in peripheral deep veins and possibly lessen the tendency toward
postphlebitic syndrome. The proper dosage regimen to minimize
hemorrhage has not been determined. Pulmonary emboli can be lysed by tPA. IV infusion is as effective as intrapulmonary. Significant complications can be minimized, particularly if major vessel catheterization can be avoided for diagnosis. Even after catheterization for pulmonary angiography, however,
thrombolytic therapy appears quite promising. The use of
thrombolytic agents for embolic-
thrombotic stroke is less promising: therefore, the risk of hemorrhagic complication may not outweigh the potential benefit.
Thrombolytic therapy thus offers the potential for significant impact on the practice of emergency medicine.