The uncertain role of thrombolytic therapy in the treatment of pulmonary embolism.

IED20006 THE FIRST clinical report of the use of a thrombolytic agent (streptokinase) to treat acute pulmonary embolism (PE) appeared in 1964,1 and the first randomized clinical trial comparing urokinase plus heparin with heparin alone was published in 1970.2 A randomized clinical trial comparing urokinase to streptokinase in the treatment of PE was published in 1974.3 The first report of a third thrombolytic agent, recombinant tissue-type plasminogen activator, in the treatment of acute PE was published by Bounameaux et al4 in 1985. The US Food and Drug Administration approved streptokinase in 1977, urokinase in 1978, and recombinant tissuetype plasminogen activator in 1990 for the treatment of acute PE.5 Despite more than 3 decades of experience with these thrombolytic agents, their role in the treatment of PE remains uncertain and controversial.