Efficacy and Safety of Low Molecular Weight Heparin, Unfractionated Heparin and Warfarin for Thrombo-Embolism Prophylaxis in Orthopaedic Surgery: A Meta-Analysis of Randomised Clinical Trials

Abstract

The efficacy and safety of low molecular weight heparin (LMWH), unfractionated heparin (UFH) and warfarin for prophylaxis of thrombo-embolism in orthopaedic surgery were compared using meta-analysis techniques. Twenty-two studies were included, 2 of which compared LMWH to warfarin. The mean probabilities to develop deep-vein thrombosis (DVT), pulmonary embolism and major and minor bleeding using UFH were: 0.21 (95% confidence interval, CI: 0.18-0.24); 0.01 (95% CI: 0.01-0.02); 0.05 (95% CI: 0.03-0.07), and 0.19 (95 % CI: 0.17-0.22), respectively. The relative risk (RR) of DVT for LMWH vs. UFH was 0.76 (95% CI: 0.60-0.91), p < 0.05 and for LMWH vs. warfarin 0.78 (95% CI: 0.69-0.87), p < 0.05. The RR of minor bleeding for LMWH vs. UFH was 0.76 (95% CI: 0.64-0.92), p < 0.05. The RR of minor bleeding for LMWH vs. warfarin was 3.28 (95% CI: 2.21-4.70), p < 0.05. Conclusion: in orthopaedic surgery, LMWH is significantly superior to both UFH and warfarin in the prevention of DVT and results in significantly less minor bleeding complications when compared to UFH, but significantly more minor bleeding when compared to warfarin.

Thromboembolic complications after total hip replacement

“…Similar results have been reported in a meta-analysis of various randomized clinical trials by Palmer and colleagues [16], who demonstrated that LMWH is significantly superior both to UFH and warfarin in the prevention of DVT in orthopedic patients. In this meta-analysis the use of low molecular weight heparin rather than low-dose UFH was associated with a relative risk for DVT of 0.76 (95% CI 0.6-0.91).…”

Prevention of venous thromboembolism in patients admitted to Australian hospitals: summary of National Health and Medical Research Council clinical practice guideline

“…3 These statistics make VTE a major patient safety issue for hospitals. [5][6][7] As prophylaxis is known to reduce the rate of VTE, [8][9][10] the National Institute of Clinical Studies, an institute of the National Health and Medical Research Council (NHMRC), identified the need to address the underuse of preventive measures for VTE in Australian hospitals as a clinical priority. 11 This paper presents the latest recommendations contained within the NHMRC's Clinical Practice Guideline for the prevention of VTE in patients admitted to Australian hospitals, as one part of the strategy to increase appropriate VTE prophylaxis.…”

Whither Thromboprophylaxis After Total Hip Replacement?

“…These passive measures have no obvious adverse consequences, unlike effective anticoagulation, but relying solely on such means implies rejection of the now extensive evidence for the efficacy of heparin, and its modern variant low-molecular-weight heparin (LMWH), in the prevention of postoperative DVT, with minimal risk of haemorrhage. [15][16][17] Other chemical approaches to the prevention of postoperative DVT have included the use of dextran, warfarin and aspirin. None has been shown to be as effective as heparin.…”

“…15,17,19,20 The problem with using death as an endpoint for an operation with low mortality is that extremely large trials are needed to demonstrate that the overall mortality is reduced. Such trials have not been carried out.…”