Title : Are Direct Oral Anticoagulants (DACs) superior to Low Molecular Weight Heparins (LMWHs) for thromboprophylaxis after elective hip replacement surgery
Abstract:
Disclaimer: This research project was completed as part of the Year 3 MBChB curriculum requirements at the University of Birmingham. The research was conducted in the context of a supervised student research module and is not intended for publication as it does not reflect a full systematic review. It should therefore be viewed as a student-led research exercise.
Introduction: Venous Thrombo Embolism (VTE) is a coagulative disorder defined by the formation of fibrin-rich clots within the deep venous system which have the fatal potential to embolise to the pulmonary circulation. Traditionally, thromboprophylaxis has been achieved using Low Molecular Weight Heparins (LMWHs). However, Direct Oral AntiCoagulants (DOACs) may offer an early promise as an alternative due to their ease of administration and favourable efficacy and safety profiles.
Review Question: This review analyses the best available literature to determine whether DOACs demonstrate clinical superiority over LMWHs in preventing VTE in patients undergoing elective hip replacement surgery.
Methods: The Turning Research Into Practice (TRIP) medical database, National Institute for Health and Care Excellence (NICE) evidence database, and MEDLINE were searched for guidelines from inception to December 2024. The guideline was appraised using the AGREE II tool. Systematic reviews and primary studies were sourced from PubMed, the Cochrane Library and MEDLINE, which were searched from 2018 to December 2024. Systematic reviews were appraised using the CASP Critical Appraisal Checklist and primary studies were appraised using the CASP Checklist for Cohort Studies and the Cochrane Risk of Bias tools.
Review Findings: Current guidelines support the use of both LMWHs and DOACs for thromboprophylaxis following elective hip surgery. Further analysis of systematic reviews and primary studies suggests DOACs are equally effective for thromboprophylaxis following elective hip replacement surgery and may offer advantages over LMWHs. Furthermore, no significant difference in the risk of major bleeding was identified between the two groups. However, all three primary studies included in this review were conducted outside of Europe, where healthcare systems and patient characteristics differ from the NHS, but some of the findings can still be applied locally, particularly due to Birmingham’s large ethnic diversity.
Conclusion: The preference for LMWH over DOACs in thromboprophylaxis for elective hip replacement surgery is due to a combination of higher quality evidence supporting their use, historical guidelines, and clinical familiarity. Current evidence suggests DOACs have the potential to become the first-line option for thromboprophylaxis following elective hip surgery. However, the lack of statistically significant findings and valid randomised controlled trials directly addressing our review question limits definitive conclusions on clinical utility. Additional high-quality research is needed to assess their benefits within the UK healthcare system. Dependent on these findings, NICE guideline NG89 should be re-evaluated accordingly. Furthermore, limitations in conducting this research should be considered. The search strategy for literature was limited to English publications due to the lack of lingually diverse authors and there was no expert to develop the search strategy for this literature review with a small selection of databases accessed.
