Thrombolysis inMyocardial Infarction (TIMI) Trial, Phase I:acomparison between intravenous tissue plasminogen activator andintravenous streptokinase*

Intravenous administration of80mg ofrecombinant tissue plasminogen activator (rt- PA,40,20,and20mg insuccessive hours) andstreptokinase (SK,1.5million units over1hr) was compared inadouble-blind, randomized trial in290patients withevolving acutemyocardial infarc- tion. Thesepatients entered thetrial within 7hroftheonsetofsymptomsandunderwent baseline coronaryarteriography before thrombolytic therapy was instituted. Ninety minutes after thestart of thrombolytic therapy, occluded infarct-related arteries hadopened in62%of113patients inthert-PA and31%of119patients intheSK group(p<.001). Twice asmany occluded infarct-related arteries opened after rt-PA compared withSKatthetimeofeachofsevenangiograms obtained during thefirst 90minafter commencing thrombolytic therapy. Regardless ofthetimefromonsetofsymptomsto treatment, more arteries wereopened after rt-PA thanSK.Thereduction incirculating fibrinogen and plasminogen andtheincrease incirculating fibrin split products at3and24hrweresignificantly less in patients treated withrt-PA thaninthose treated withSK(p<.001). Theoccurrenceofbleeding events, administration ofblood transfusions, andreocclusion oftheinfarct-related artery was comparable inthe twogroups.Thus, inpatients with acutemyocardial infarction, rt-PA elicited reperfusion intwice as many occluded infarct-related arteries ascompared withSKateachofsevenserial observations during thefirst 90minafter onsetoftreatment. Circulation 76,No.1,142-154, 1987.