From the Guidelines
Aspirin should be prescribed at a dose of 75-100 mg daily for DVT prophylaxis, as this dose provides an adequate antiplatelet effect while minimizing bleeding risk, according to the most recent guidelines 1. The most common regimen is 75-100 mg (low-dose) once daily. For patients at risk for recurrent VTE who are not considered candidates for an anticoagulant, or who choose to stop anticoagulant therapy, aspirin may be considered an option 1. Some guidelines suggest considering aspirin 75 mg or 150 mg daily in people who decline extended anticoagulation treatment 1. Aspirin works by irreversibly inhibiting cyclooxygenase enzymes, reducing thromboxane A2 production and preventing platelet aggregation. While effective for certain indications, aspirin is generally considered less potent than anticoagulants like low molecular weight heparin or direct oral anticoagulants for DVT prophylaxis. Key considerations for aspirin use in DVT prophylaxis include:
- Patient risk factors for VTE and bleeding
- Specific indication for DVT prophylaxis (e.g. orthopedic surgery, immobility)
- Alternative prophylaxis options for patients with aspirin allergy, active bleeding, or high bleeding risk
- Duration of therapy, which depends on the specific indication and patient risk factors, typically ranging from 10-35 days post-surgery or throughout periods of immobility. Patients should take aspirin with food to minimize gastrointestinal irritation. The evidence from the 2021 Chest guideline update 1 supports the use of aspirin for DVT prophylaxis in certain patient populations, and provides guidance on dosing and duration of therapy.
From the Research
Aspirin Dose for DVT Prophylaxis
- The optimal dose of aspirin for Deep Vein Thrombosis (DVT) prophylaxis is not universally established, but several studies provide insights into its efficacy and safety in different patient populations 2, 3, 4, 5.
- A study published in The Journal of Arthroplasty in 2021 found that low-dose aspirin (75 mg once daily) was safe and effective for VTE prophylaxis after total hip or knee arthroplasty, with no significant difference in complication rates compared to low-molecular-weight heparin (LMWH) 2.
- Another study published in PloS one in 2020 compared aspirin (81-mg twice daily) with LMWH for VTE prevention in orthopaedic trauma patients and found no evidence of superiority between the two treatments 3.
- A study published in The Journal of Arthroplasty in 2021 found that 30 days of aspirin prophylaxis, regardless of the dose used (81 mg twice daily or 325 mg twice daily), was adequate for preventing VTE after total knee arthroplasty 4.
- A randomized controlled trial published in the Chinese Medical Journal in 2021 found that 100 mg aspirin twice daily was comparable to rivaroxaban in terms of efficacy and safety for VTE prophylaxis following primary total hip arthroplasty 5.
Key Findings
- Aspirin doses ranging from 75 mg to 325 mg daily have been studied for DVT prophylaxis, with varying results 2, 3, 4, 5.
- The duration of aspirin prophylaxis is also an important consideration, with 30 days being a commonly recommended duration 4.
- Aspirin has been found to be a safe and effective alternative to LMWH and other anticoagulants for VTE prophylaxis in certain patient populations 2, 3, 5.
Study Limitations
- The studies had different patient populations, aspirin doses, and durations of prophylaxis, making it challenging to draw definitive conclusions about the optimal aspirin dose for DVT prophylaxis 2, 3, 4, 5.
- Further research is needed to fully establish the efficacy and safety of aspirin for DVT prophylaxis in different clinical settings 2, 3, 4, 5.