Comparison of front-loaded recombinant tissue-type plasminogen activator, anistreplase and combination thrombolytic therapy for acute myocardial infarction: results of the Thrombolysis in Myocardial Infarction (TIMI) 4 trial.
OBJECTIVE
The aim of our study was to determine a superior thrombolytic regimen from three: anistreplase (APSAC), front-loaded recombinant tissue-type plasminogen activator (rt-PA) or combination thrombolytic therapy.


BACKGROUND
Although thrombolytic therapy has been shown to reduce mortality and morbidity after acute myocardial infarction, it has not been clear whether more aggressive thrombolytic-antithrombotic regimens could improve the outcome achieved with standard regimens.


METHODS
To address this issue, 382 patients with acute myocardial infarction were randomized to receive in a double-blind fashion (along with intravenous heparin and aspirin) APSAC, front-loaded rt-PA or a combination of both agents. The primary end point "unsatisfactory outcome" was a composite clinical end point assessed through hospital discharge.


RESULTS
Patency of the infarct-related artery (Thrombolysis in Myocardial Infarction [TIMI] grade 2 or 3 flow) at 60 min after the start of thrombolysis was significantly higher in rt-PA-treated patients (77.8% vs. 59.5% for APSAC-treated patients and 59.3% for combination-treated patients [rt-PA vs. APSAC, p = 0.02; rt-PA vs. combination, p = 0.03]). At 90 min, the incidence of both infarct-related artery patency and TIMI grade 3 flow was significantly higher in rt-PA-treated patients (60.2% had TIMI grade 3 flow vs. 42.9% and 44.8% of APSAC- and combination-treated patients, respectively [rt-PA vs. APSAC, p < 0.01; rt-PA vs. combination, p = 0.02]). The incidence of unsatisfactory outcome was 41.3% for rt-PA compared with 49% for APSAC and 53.6% for the combination (rt-PA vs. APSAC, p = 0.19; rt-PA vs. combination, p = 0.06). The mortality rate at 6 weeks was lowest in the rt-PA-treated patients (2.2% vs. 8.8% for APSAC and 7.2% for combination thrombolytic therapy [rt-PA vs. APSAC, p = 0.02; rt-PA vs. combination, p = 0.06]).


CONCLUSIONS
Front-loaded rt-PA achieved significantly higher rates of early reperfusion and was associated with trends toward better overall clinical benefit and survival than those achieved with a standard thrombolytic agent or combination thrombolytic therapy. These findings support the concept that more rapid reperfusion of the infarct-related artery is associated with improved clinical outcome.
Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts.
C P
CP
Cannon
C H
CH
McCabe
D J
DJ
Diver
S
S
Herson
R M
RM
Greene
P K
PK
Shah
R F
RF
Sequeira
F
F
Leya
J M
JM
Kirshenbaum
R D
RD
Magorien
D000368:Aged; D016255:Anistreplase / Q000009:adverse effects / Q000627:therapeutic use*; D001241:Aspirin / Q000627:therapeutic use; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D006493:Heparin / Q000627:therapeutic use; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000401:mortality; D015912:Thrombolytic Therapy; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*; D014654:Vascular Patency
D016255:Anistreplase; D006493:Heparin; D010959:Tissue Plasminogen Activator; D001241:Aspirin