What is the efficiency of DVT prophylaxis?

From the Guidelines

DVT prophylaxis is highly effective when appropriately implemented, reducing the risk of venous thromboembolism by 60-80% in high-risk patients. The most recent and highest quality study, published in 2022 1, recommends that every patient undergoing a major, elective abdominal or pelvic surgery should have VTE prophylaxis, using a combination of a compression stocking and/or intermittent pneumatic compression together with either a low molecular weight heparin (LMWH) or unfractionated heparin.

Key Recommendations

• For medical patients, low molecular weight heparins like enoxaparin (40mg subcutaneously once daily) or fondaparinux (2.5mg subcutaneously once daily) are recommended.
• Surgical patients typically receive enoxaparin 40mg subcutaneously once daily or 30mg twice daily, starting 12 hours before surgery or 12-24 hours after.
• Unfractionated heparin (5000 units subcutaneously every 8-12 hours) is an alternative, particularly for patients with renal impairment.
• Mechanical methods like graduated compression stockings or intermittent pneumatic compression devices provide approximately 60% risk reduction when pharmacological methods are contraindicated.

Duration of Prophylaxis

• Prophylaxis should continue throughout hospitalization for medical patients and for 7-10 days post-surgery for surgical patients.
• Extended prophylaxis (28-35 days) is recommended for high-risk orthopedic surgeries, as suggested by the American College of Chest Physicians evidence-based clinical practice guidelines 1.

Special Considerations

• Patients at high risk for bleeding events or in whom heparin is contraindicated may benefit from intermittent pneumatic compression, as recommended by the American College of Physicians 1.
• The use of VTE-prophylaxis for surgical patients is well-established, but the benefit of extended prophylaxis for 28 days after discharge is controversial, with some studies suggesting a significant reduction in the prevalence of symptomatic DVT 1.

From the FDA Drug Label

The primary efficacy endpoint, venous thromboembolism (VTE), was a composite of documented deep vein thrombosis (DVT) and/or documented symptomatic pulmonary embolism (PE) reported up to Day 11 The efficacy data are provided in Table 7 and demonstrate that under the conditions of the trial fondaparinux sodium was associated with a VTE rate of 8.3% compared with a VTE rate of 19.1% for enoxaparin sodium for a relative risk reduction of 56% (95% CI: 39%, 70%; P <0.001). All DVT49/6247.9% b (5.9,10.2) 117/62318.8% (15.8,22.1)

The efficiency of DVT prophylaxis with fondaparinux sodium is 56% relative risk reduction compared to enoxaparin sodium, with a VTE rate of 8.3% and a DVT rate of 7.9% 2.

• Key points:
  • Fondaparinux sodium reduces the risk of VTE by 56% compared to enoxaparin sodium.
  • The VTE rate for fondaparinux sodium is 8.3%.
  • The DVT rate for fondaparinux sodium is 7.9%.

From the Research

DVT Prophylaxis Efficiency

The efficiency of DVT prophylaxis can be evaluated based on various studies that have investigated the effectiveness of different prophylactic measures.

• The use of pharmacological primary prophylaxis of venous thromboembolism (VTE) has been associated with an impressive decrease in the incidence of DVT and related complications 3.
• Non-pharmacological measures, such as intermittent pneumatic compression devices (IPCD) and graduated compression stockings, have also been shown to be effective in reducing the risk of DVT 4, 5.
• The implementation of decision-making tools based on risk factor assessment can improve the prescription of appropriate VTE prophylaxis 6.

Reduction in DVT Risk

• A meta-analysis of 15 studies found that IPC devices reduced the risk of DVT by 60% compared to no prophylaxis 4.
• A randomized trial of prophylaxis with low-molecular weight heparin (LMWH) in patients undergoing ambulatory arthroscopic knee surgery found that the risk of DVT was significantly lower in the treatment group (1.5%) compared to the control group (15.6%) 7.
• Another study found that low-dose heparin-based prophylaxis can further reduce the incidence of PE, but may also increase the risk of minor and major postoperative hemorrhages 5.

Prophylaxis Strategies

• Various prophylaxis strategies are available, including pharmacological and non-pharmacological measures, and the choice of strategy depends on the individual patient's risk factors and clinical situation 3, 6.
• The use of novel oral anticoagulants, such as dabigatran, rivaroxaban, and apixaban, may be indicated in elective surgery, particularly in patients with expected poor adherence to parenteral routes 3, 6.