Enoxaparin vs. unfractionated heparin with fibrinolysis for ST-elevation myocardial infarction in elderly and younger patients: results from ExTRACT-TIMI 25.
OBJECTIVE
To determine the effects of age on outcomes in patients with STEMI treated with a strategy of enoxaparin (ENOX) vs. unfractionated heparin (UFH).


RESULTS
In the ExTRACT-TIMI 25 trial, 20,479 patients with STEMI were randomized in a double-blind fashion to UFH or ENOX. A novel reduced dose of ENOX was administered to patients >or=75 years, and a reduced dose in those with an estimated creatinine clearance of < 30 mL/min. Anti-Xa levels were measured in a subset of patients (n = 73). The exposure to anti-Xa over time was lower in the elderly (AUC(0-12 h) P < 0.0001; AUC(steady-state) P = 0.0046). The relative risk reduction (RR) with ENOX on the primary endpoint, i.e. death or non-fatal recurrent myocardial infarction, was greater in patients < 75 years (20%) than > 75 years (6%), but the absolute benefits were similar. When compared with UFH, ENOX was associated with an RR of 1.67 for major bleeding, but the magnitude of the excess risk tended to be lower (RR = 1.15) in patients >or= 75 years assigned to ENOX.


CONCLUSIONS
A dose reduction of ENOX in the elderly appears to be helpful in ameliorating bleeding risk. A strategy of ENOX was superior to UFH in both young and elderly patients with STEMI treated with fibrinolysis.
White
Harvey D
HD
Green Lane Cardiovascular Service, Auckland City Hospital, Auckland 1030, New Zealand. harveyw@adhb.govt.nz
Braunwald
Eugene
E
Murphy
Sabina A
SA
Jacob
Ashok J
AJ
Gotcheva
Nina
N
Polonetsky
Leonid
L
Antman
Elliott M
EM
D000328:Adult; D000367:Age Factors; D016757:Death, Sudden, Cardiac / Q000209:etiology; D004311:Double-Blind Method; D017984:Enoxaparin / Q000627:therapeutic use; D005260:Female; D006470:Hemorrhage / Q000209:etiology; D006493:Heparin / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy*; D055502:Secondary Prevention; D016896:Treatment Outcome
D017984:Enoxaparin; D006493:Heparin