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Clinical Question:
Is low-molecular-weight heparin more effective than unfractionated heparin
in the treatment of patients with acute coronary syndromes?
Bottom Line:
In the SYNERGY trial, patients continued to experience adverse cardiac
events through long-term follow-up. The effect of enoxaparin on death or MI
compared with that of unfractionated heparin at 6 months was similar to that
observed at 30 days in the overall trial and in the consistent-therapy
group. One-year death rates were also similar in both groups. High-risk
patients with ACS remain susceptible to continued cardiac events despite
aggressive therapies.
Reference:
High-risk patients with acute coronary syndromes treated with
low-molecular-weight or unfractionated heparin: outcomes at 6 months and 1
year in the SYNERGY trial.
Mahaffey KW, Cohen M, Garg J, Antman E, Kleiman NS, Goodman SG, Berdan LG,
Reist CJ, Langer A, White HD, Aylward PE, Col JJ, Ferguson JJ 3rd, Califf RM;
SYNERGY Trial Investigators. JAMA. 2005 Nov 23;294(20):2594-600.
Study Design:
Randomized controlled trial (double-blinded)
Synopsis:
The SYNERGY trial comparing enoxaparin and unfractionated heparin in
high-risk patients with acute coronary syndromes (ACS) showed that
enoxaparin was not inferior to unfractionated heparin in reducing death or
nonfatal myocardial infarction (MI) at 30 days. To evaluate continued risk
in this patient cohort through 6-month and 1-year follow-up. Overall, 9978
patients were randomized from August 2001 through December 2003 in 487
hospitals in 12 countries. Patients were followed up for 6 months and for 1
year. MAIN OUTCOME MEASURES: Six-month outcomes were death, nonfatal MI,
revascularization procedures, stroke, and site-investigator-reported need
for rehospitalization; 1-year outcome was all-cause death. Six-month and
1-year follow-up data were available for 9957 (99.8%) and 9608 (96.3%) of
9978 patients, respectively; 541 patients (5.4%) had died at 6 months and
739 (7.4%) at 1 year. Death or nonfatal MI at 6 months occurred in 872
patients receiving enoxaparin (17.6%) vs 884 receiving unfractionated
heparin (17.8%) (hazard ratio [HR], 0.98; 95% confidence interval [CI],
0.89-1.07; P = .65). In the subgroup of patients receiving consistent
therapy, ie, only enoxaparin or unfractionated heparin during the index
hospitalization (n = 6138), a reduction in death or nonfatal MI with
enoxaparin was maintained at 180 days (HR, 0.85; 95% CI, 0.75-0.95; P =
.006). Rehospitalization within 180 days occurred in 858 patients receiving
enoxaparin (17.9%) and 911 receiving unfractionated heparin (19.0%) (HR,
0.94; 95% CI, 0.85-1.03; P = .17). One-year all-cause death rates were
similar in the 2 treatment groups (380/4974 [7.6%] for enoxaparin vs
359/4948 [7.3%] for unfractionated heparin; HR, 1.06; 95% CI, 0.92-1.22; P =
.44). One-year death rates in patients receiving consistent therapy were
also similar (251/3386 [7.4%] for enoxaparin vs 213/2720 [7.8%] for
unfractionated heparin; HR, 0.95; 95% CI, 0.79-1.14; P = .55). |