The origin of thrombolytic therapy.

The origin of thrombolytic therapy is briefly reviewed. It began 40 years ago with the demonstration that the injection into patients of a partially purified activator of the native plasminogen-plasmin enzyme system was capable of dissolving clotted blood and fibrinous loculations in the chest. However, the application of this form of therapy for the dissolution of intravascular thrombi had to await a series of further developments, including extensive purification of the thrombolytic agents, evidence that plasminogen activators would be more appropriate than plasmin for thrombolysis and proof, first in animals and then in humans, that thrombi could be dissolved by the systemic administration of plasminogen activators. The first study of thrombolytic therapy in acute myocardial infarction was reported in 1958. However, despite many studies conducted during the next 20 years, with encouraging reductions in mortality, thrombolytic therapy for acute myocardial infarction became established only when angiography provided visual evidence of the presence of a thrombus obstructing an infarct-related artery and of the achievement of prompt lysis with the administration of thrombolytic agents.