From the Guidelines
Enoxaparin (Clexane) is generally preferred over aspirin for thromboprophylaxis in most post-surgical patients, particularly those at moderate to high risk for venous thromboembolism (VTE). The typical regimen is enoxaparin 40mg subcutaneously once daily, starting 12 hours before surgery or 6-12 hours after surgery, and continuing for 7-14 days for general surgery or up to 35 days for orthopedic procedures like hip or knee replacements 1. For patients with renal impairment, dose adjustment is necessary. Enoxaparin works by binding to antithrombin III, enhancing its inhibition of factor Xa and thrombin, providing more predictable anticoagulation than aspirin, which only inhibits platelet aggregation through cyclooxygenase inhibition.
Some key points to consider when choosing between enoxaparin and aspirin include:
- The patient's bleeding risk: Enoxaparin may be preferred for patients at high risk of bleeding, as it has a more predictable anticoagulant effect compared to aspirin 1.
- Type of surgery: Enoxaparin is generally preferred for orthopedic procedures, while aspirin may be suitable for low-risk patients or specific orthopedic protocols 1.
- Mobility status: Mechanical prophylaxis with compression stockings or intermittent pneumatic compression devices should be used alongside pharmacological methods when appropriate, especially in patients with contraindications to anticoagulants 1.
- Comorbidities: The choice between medications should consider the patient's comorbidities, such as renal impairment, which may require dose adjustment of enoxaparin 1.
Overall, the decision to use enoxaparin or aspirin for thromboprophylaxis should be based on the individual patient's risk factors and medical history, with enoxaparin being the preferred choice for most post-surgical patients at moderate to high risk for VTE.
From the Research
Thromboprophylaxis Comparison
The comparison between Aspirin and Clexane (enoxaparin) for thromboprophylaxis post-surgery is a critical consideration in preventing venous thromboembolism (VTE). The evidence suggests that:
- Aspirin is perceived to be non-inferior to enoxaparin for the prevention of VTE following elective arthroplasty of the hip or knee 2.
- A systematic review and meta-analysis found no significant difference in overall VTE rates when comparing aspirin versus enoxaparin, with a relative risk (RR) of 0.84 (95% CI: 0.41 to 1.75; p=0.65) 2.
- Aspirin and enoxaparin conferred similar bleeding risks, with no significant differences in the rates of major or minor bleeding events between the two groups 2, 3.
Bleeding Risks
The bleeding risks associated with aspirin and enoxaparin are:
- Aspirin and enoxaparin were found to have lower bleeding risks compared to rivaroxaban, with a significant difference in postoperative bleeding rates (P < .05) 3.
- The rates of major bleeding were lower in the aspirin and enoxaparin groups, although the differences were not significant 3.
Efficacy and Safety
The efficacy and safety of aspirin compared to enoxaparin or rivaroxaban are:
- Aspirin was found to be at least as effective as modified rivaroxaban for preventing clinically important VTE among patients undergoing hip or knee arthroplasty 4.
- The extended aspirin regimen was associated with a similar VTE rate (1.04%) compared to the inpatient enoxaparin group (1.04%) and the modified rivaroxaban group (0.66%) 4.
- Aspirin can be considered a safe and effective agent in the prevention of VTE after total hip or total knee replacement 4.
Cost-Effectiveness
The cost-effectiveness of enoxaparin compared to other agents is:
- Fondaparinux was found to be more effective and cost-saving than enoxaparin for extended prophylaxis of VTE following major orthopedic surgery, with savings of €48.83 per patient at 30 days, €72.13 at 1 year, and €74.36 at 5 years 5.
- Fondaparinux was consistently more effective than enoxaparin in preventing VTE in patients undergoing major orthopedic surgery, irrespective of the established composite outcomes used 6.