Optimal anticoagulation duration of unfractionated and low molecular weight heparin in non-ST elevation acute coronary syndrome: a systematic review of the literature

Abstract

Introduction: In this PCI era, non-invasive management for patients presenting with non-ST elevation acute coronary syndrome continues to be relevant in several clinical circumstances. The duration of anticoagulation in non-invasively treated group is not clear. The use of heparin can be associated with fatal side effects. Thus, defining the optimal duration of therapy has significant implications for patient safety and cost.

Methods: Literature search was conducted using Medline (PubMed and Ovid SP), Embase, Cochrane Central Register of Controlled Clinical Trials (CENTRAL) and Cochrane Database of Systematic Review (CDSR) from the inception of these databases till present (August 2013). Only studies on humans and in English language were included. We included only published clinical trials which used UFH or LMWH as the anticoagulation agent.

Results: Initial search revealed 548 studies with 182 meeting inclusion criteria for full review. The duration of therapy was reported in 20 of 182 studies with an average treatment duration of 2-8 days. There was a trend towards increased bleeding without significant improvement in cardiovascular outcomes when anticoagulation was continued for more than 5-7 days. No single trial directly analyzed the composite end point outcome or adverse events in correlation with the duration of anticoagulation.

Conclusion: There is a lack of good quality evidence to define the optimal duration of anticoagulation in the management of NSTE ACS. Well-designed, methodologically rigorous database studies are required to determine the shortest duration of therapy which achieves the benefits of anticoagulants while minimizing the costs and risks associated with prolonged anticoagulant use.

Keywords: Anticoagulation duration; Low molecular weight heparin; Non-ST elevation myocardial infarction; Systematic review; Unfractionated heparin; Unstable angina.