In this article, the authors studied aspirin-only, and aspirin combined with UH for VTE prophylaxis after elective primary total hip arthroplasty and total knee arthroplasty. They found similar VTE events, but shorter hospital stays, higher hemoglobin values and lower blood transfusion requirements in the aspirin-only group.
There are no studies that directly compare aspirin-only with aspirin and UH for VTE prophylaxis after elective primary THA and TKA. Therefore, the present study gives useful information to surgeons who choose to administer these pharmacologic agents for VTE prophylaxis of their patients. Based on the study’s results, UH as an additional mode of VTE prophylaxis when prescribing aspirin in these patients is not recommended.
As expected, aspirin in addition to UH showed a synergic action and increased complications (lower hemoglobin values and higher transfusion requirements); the similar VTE prophylaxis effect can be explained by the different mechanism of action of the two drugs in the coagulation cascade.
Available guidelines recommend low molecular-weight heparin (LMWH) over other agents for VTE prophylaxis. In this context, the study seems outdated as not many surgeons/hospitals currently apply these protocols for VTE prophylaxis of their patients undergoing elective primary THA and TKA. It would have been more useful if the authors had compared aspirin-only with LMWH, which is the preferred option for VTE prophylaxis, according to most guidelines.
Adherence to guidelines with respect to preference, doses, time of initiation and duration of treatment in clinical practice is another concern. The authors refer to their own protocol and the American Academy of Orthopaedic Surgeons 2011 guidelines for prophylaxis; UH was given as a 5000-IU subcutaneous injection based on historical studies and hospital postoperative protocol, and aspirin was given as a 325-mg twice-daily dose for 28 days.
Last, and most importantly, VTE can occur up to 3 months after THA and TKA. As clarified by the authors, in this series the patients were not routinely checked for VTE; therefore, subclinical VTE was not included in the analysis, which is a major limitation of the study.
Flevas DA, et al. EFORT Open Rev.2018 doi:10.1302/2058-5241.3.170018.
Andreas F. Mavrogenis, MD
Assistant professor of orthopaedics
National and Kapodistrian University of Athens, School of Medicine
Disclosures: Mavrogenis reports no relevant financial disclosures.