Enoxaparin is superior to unfractionated heparin in patients with ST elevation myocardial infarction undergoing fibrinolysis regardless of the choice of lytic: an ExTRACT-TIMI 25 analysis.
OBJECTIVE
We compared outcomes of ST-elevation myocardial infarction (STEMI) patients randomized to a strategy of either enoxaparin or unfractionated heparin (UFH) to support fibrinolysis.


RESULTS
In the Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment-Thrombolysis in Myocardial Infarction Study 25 (ExTRACT-TIMI 25) trial, 20,479 patients undergoing fibrinolysis for STEMI with a fibrin-specific agent (N = 16,283) or streptokinase (SK) (N = 4139) were randomized to enoxaparin throughout their hospitalization or UFH for at least 48 h. The primary end point of death or nonfatal recurrent MI through 30 days occurred in 12.0% of patients in the UFH and 9.8% in the enoxaparin groups when treated with fibrin-specific lytics [odds ratio(adjusted) (OR(adj)) 0.78; 95% CI 0.70-0.87; P < 0.001] and 11.8 vs. 10.2%, respectively, when treated with SK (OR(adj) 0.83; 95% CI 0.66-1.04; P = 0.10; P(interaction) = 0.58). Major bleeding rates including intracranial hemorrhage within the fibrin-specific cohort were 1.2 and 2.0% in the UFH and enoxaparin groups, respectively (P < 0.001) and 2.0% in UFH and 2.4% in enoxaparin patients in the SK cohort (P = 0.16). Interaction tests between antithrombin- and lytic-type were non-significant (P = 0.20). Death, nonfatal MI, or major bleeding was significantly reduced with enoxaparin in the fibrin-specific cohort (OR(adj) 0.82; 95% CI 0.74-0.91; P < 0.001) and favoured enoxaparin in the SK cohort (OR(adj) 0.89; 95% CI 0.72-1.10; P = 0.29; P(interaction) = 0.53).


CONCLUSIONS
The benefits of an enoxaparin strategy over UFH were observed in both SK and fibrin-specific-treated STEMI patients. Therefore, an enoxaparin strategy is preferred over UFH to support fibrinolysis for STEMI regardless of lytic agent.
Giraldez
Roberto R
RR
TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 350 Longwood Avenue, 1st Floor, Boston, MA 02115, USA. rgiraldez@partners.org
Nicolau
José Carlos
JC
Corbalan
Ramon
R
Gurfinkel
Enrique P
EP
Juarez
Ursulo
U
Lopez-Sendon
Jose
J
Parkhomenko
Alexander
A
Molhoek
Peter
P
Mohanavelu
Satishkumar
S
Morrow
David A
DA
Antman
Elliott M
EM
D000368:Aged; D003657:Decision Making; D017984:Enoxaparin / Q000627:therapeutic use*; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006493:Heparin / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy*; D015425:Myocardial Reperfusion / Q000379:methods; D016896:Treatment Outcome
D017984:Enoxaparin; D005343:Fibrinolytic Agents; D006493:Heparin