Heparin versus placebo for acute coronary syndromes.
BACKGROUND
Acute coronary syndromes (ACS) represent a spectrum of disease including unstable angina (UA) and non-ST segment myocardial infarction (NSTEMI). Despite treatment with aspirin, beta-blockers and nitroglycerin, UA/NSTEMI is still associated with significant morbidity and mortality. Although emerging evidence suggests that low molecular weight heparin (LMWH) is more efficacious compared to unfractionated heparin (UFH), there is limited data to support the role of heparins as a drug class in the treatment of ACS.


OBJECTIVE
To determine the effect of heparins (UFH and LMWH) compared with placebo for the treatment of patients with ACS.


METHODS
We searched the Cochrane Central Register of Controlled Trials on The Cochrane Library (issue 4, 2002), MEDLINE (1966 to May 2002), EMBASE (1980 to May 2002) and CINAHL (1982 to May 2002). Authors of included studies and pharmaceutical industry representatives were contacted to determine if unpublished studies which met the inclusion criteria were available.


METHODS
Randomized controlled trials of parenteral UFH or LMWH versus placebo in people with ACS (UA or NSTEMI).


METHODS
Two reviewers independently assessed quality of studies. Data were extracted independently by two reviewers. Study authors were contacted to verify and clarify missing data.


RESULTS
Eight studies (3118 participants) were included in this review. We found no evidence for difference in overall mortality between the groups treated with heparin and placebo (RR = 0.84, 95% CI 0.36 to 1.98). Heparins reduced the occurrence of MI (RR = 0.40, 95% CI 0.25 to 0.63, NNT = 33). An increase in the incidence of minor bleeds (RR = 6.80, 95% CI 1.23 to 37.49, NNH = 17).


CONCLUSIONS
Compared to placebo, patients treated with heparins had similar risk of mortality, revascularization, recurrent angina, major bleeding and thrombocytopenia. However, those treated with heparins had decreased risk of MI and a higher incidence of minor bleeding.
Magee
K D
KD
Dalhousie University, Department of Emergency Medicine, Queen Elizabeth II Health Sciences Centre, Halifax Infirmary, 1796 Summer Street, Halifax, Nova Scotia, Canada B3H 3A7. kmagee@dal.ca
Campbell
S G
SG
Moher
D
D
Rowe
B H
BH
D054058:Acute Coronary Syndrome / Q000188:drug therapy* / Q000401:mortality; D000789:Angina, Unstable / Q000188:drug therapy; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use*; D006493:Heparin / Q000009:adverse effects / Q000627:therapeutic use*; D006495:Heparin, Low-Molecular-Weight / Q000009:adverse effects / Q000627:therapeutic use; D006801:Humans; D009203:Myocardial Infarction / Q000517:prevention & control; D010919:Placebos / Q000627:therapeutic use; D016032:Randomized Controlled Trials as Topic
D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight; D010919:Placebos; D006493:Heparin