Heparin versus placebo for non-ST elevation acute coronary syndromes
Carlos A Andrade-Castellanos1, Luis E Colunga-Lozano, Netzahualpilli Delgado-Figueroa
1Department of Internal Medicine, Hospital Civil de Guadalajara "Dr. Juan I. Menchaca", Salvador Quevedo y Zubieta No. 750, Guadalajara, Jalisco, Mexico, 44340.
Insights
Heparins, including unfractionated heparin (UFH) and low molecular weight heparin (LMWH), did not reduce mortality in non-ST elevation acute coronary syndromes (NSTEACS). However, heparins significantly decreased myocardial infarction risk but increased minor bleeding events.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Non-ST elevation acute coronary syndromes (NSTEACS), encompassing unstable angina and NSTEMI, present significant morbidity and mortality risks despite standard treatments.
- While low molecular weight heparin (LMWH) shows potential efficacy over unfractionated heparin (UFH), data on heparins as a drug class for NSTEACS is limited.
Purpose of the Study:
- To evaluate the efficacy and safety of heparins (UFH and LMWH) versus placebo in treating patients diagnosed with NSTEACS (unstable angina or NSTEMI).
Main Methods:
- Systematic review and meta-analysis of randomized controlled trials comparing parenteral UFH or LMWH against placebo.
- Searched multiple databases including Cochrane Central Register, MEDLINE, EMBASE, CINAHL, and LILACS without language restrictions.
- Independent assessment of study quality and data extraction by two review authors.
Main Results:
- Eight studies with 3118 participants were included; no new studies were added for this update.
- Heparins showed no significant difference in overall mortality compared to placebo (RR 0.84, 95% CI 0.36 to 1.98).
- A significant reduction in myocardial infarction was observed with heparins (RR 0.40, 95% CI 0.25 to 0.63), with a number needed to benefit of 33. A trend towards increased major bleeding was noted (RR 2.05, 95% CI 0.91 to 4.60).
Conclusions:
- Heparins did not alter mortality, revascularization, recurrent angina, or thrombocytopenia risk compared to placebo.
- A decreased risk of myocardial infarction and an increased incidence of minor bleeding were associated with heparin use.
- The overall low quality of evidence necessitates cautious interpretation of these findings.
Background:
Non-ST elevation acute coronary syndromes (NSTEACS) represent a spectrum of disease including unstable angina and non-ST segment myocardial infarction (NSTEMI). Despite treatment with aspirin, beta-blockers and nitroglycerin, unstable angina/NSTEMI is still associated with significant morbidity and mortality. Although 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 NSTEACS. This is an update of a review last published in 2008.
Objectives:
To determine the effect of heparins (UFH and LMWH) compared with placebo for the treatment of patients with non-ST elevation acute coronary syndromes (unstable angina or NSTEMI).
Search Methods:
For this update the Cochrane Heart Group Trials Search Co-ordinator searched the Cochrane Central Register of Controlled Trials on The Cochrane Library (2013, Issue 12), MEDLINE (OVID, 1946 to January week 1 2014), EMBASE (OVID, 1947 to 2014 week 02), CINAHL (1937 to 15 January 2014) and LILACS (1982 to 15 January 2014). We applied no language restrictions.
Selection Criteria:
Randomized controlled trials of parenteral UFH or LMWH versus placebo in people with non-ST elevation acute coronary syndromes (unstable angina or NSTEMI).
Data Collection And Analysis:
Two review authors independently assessed quality of studies and independently extracted data.
Main Results:
There were no new included studies for this update. 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 (risk ratio (RR) = 0.84, 95% confidence interval (CI) 0.36 to 1.98). Heparins compared with placebo, reduced the occurrence of myocardial infarction in patients with unstable angina and NSTEMI (RR = 0.40, 95% CI 0.25 to 0.63, number needed to benefit (NNTB) = 33). There was a trend towards more major bleeds in the heparin studies compared to control studies (RR = 2.05, 95% CI 0.91 to 4.60). From a limited data set, there appeared to be no difference between patients treated with heparins compared to control in the occurrence of thrombocytopenia (RR = 0.20, 95% CI 0.01 to 4.24). Assessment of overall risk of bias in these studies was limited as most of the studies did not give sufficient detail to allow assessment of potential risk of bias.
Authors' Conclusions:
Compared with placebo, patients treated with heparins had a similar risk of mortality, revascularization, recurrent angina, and thrombocytopenia. However, those treated with heparins had a decreased risk of myocardial infarction and a higher incidence of minor bleeding. Overall, the evidence assessed in this review was classified as low quality according to the GRADE approach. The results presented in this review must therefore be interpreted with caution.
Related Concept Videos
01:30Anticoagulant Drugs: Low-Molecular-Weight Heparins
01:28Acute Coronary Syndrome IV: Interprofessional Care
01:30Acute Coronary Syndrome I: Introduction
01:30Acute Coronary Syndrome III: Diagnostic Studies
01:20Antiplatelet Drugs: Prostaglandin Synthesis, P2Y12 and Glycoprotein IIb/IIIa Inhibitors
Prostaglandin synthesis inhibitors, exemplified by the widely known aspirin, wield their power by irreversibly acetylating...
01:29Venous Thrombosis III: Interprofessional Care