MORE RAPID, COMPLETE, AND STABLE CORONARY THROMBOLYSIS WITH BOLUS ADMINISTRATION OF RETEPLASE COMPARED WITH ALTEPLASE INFUSION IN ACUTE MYOCARDIAL-INFARCTION

Background Early restoration and maintenance of normal (TIMI 3) blood flow during acute myocardial infarction is critical for optimal preservation of left ventricular function and survival. Recombinant plasminogen activator (r-PA, reteplase) is a nonglycosylated deletion mutant of wild-type tissue-type plasminogen activator (TPA) that has been shown to achieve more rapid and complete thrombolysis compared with other plasminogen activators in animal models. Methods and Results The RAPID Trial was designed to test the hypothesis that bolus administration of one or more dosage regimens of r-PA was superior to standard-dose alteplase (TPA) in achieving infarct-related artery patency 90 minutes after initiation of treatment. Six hundred six patients with acute myocardial infarction were randomized to one of four treatment arms: (I) TPA 100 mg IV over 3 hours, (2) r-PA as a 15-MU single bolus, (3) r-PA as a 10-MU bolus followed by 5 MU 30 minutes later, or (4) r-PA as a 10-MU bolus followed by 10 MU 30 minutes later. Coronary arteriography was per formed at 30, 60, and 90 minutes after initiation of treatment and at hospital discharge. The 10+10-MU r-PA group achieved better 90-minute and 5- to 14-day TIMI 3 flow (63% [CI, 55% to 71%] versus 49% [41% to 57%], P=.019, and 88% [82% to 94%] versus 71% [63% to 79%], P<.001, respectively) than the TPA group. The TIMI 3 flow in the 10+10-MU r-PA group at 60 minutes was equivalent to that in the TPA group at 90 minutes (51 versus 49%). Global ejection fraction and regional wall motion in the 10+10-MU r-PA group were superior to those of the TPA group at hospital discharge (53+/-1.3% versus 49+/-1.3%, P=.034; -2.19+/-0.12 versus -2.61+/-0.13 SD per chord, P=.02 respectively). The 15-MU and 10+5-MU r-PA patency and left ventricular function results were similar to those of the TPA and inferior to those of the 10+10-MU r-PA group. Bleeding complications were similar between the groups. Conclusions r-PA given as a double bolus of 10+10 MU achieves more rapid, complete, and sustained thrombolysis of the infarct-related artery than standard-dose TPA, without an apparent increased risk of complications. This was associated with improved global and regional left ventricular function at hospital discharge.