What is the recommended prophylaxis for deep vein thrombosis (DVT)?

DVT Prophylaxis Recommendations

For DVT prophylaxis, low molecular weight heparin (LMWH) is the preferred pharmacological agent for most hospitalized patients at risk of thrombosis, with a standard dose of 40mg subcutaneously once daily. 1

Risk Assessment and Indications

The need for DVT prophylaxis should be determined based on patient risk factors:

• Hospitalized patients requiring prophylaxis:

  • Active malignancy with acute medical illness or reduced mobility 2
  • Critically ill patients 2
  • Patients with additional risk factors (previous VTE, immobilization, severe obesity, etc.) 2

• Outpatients requiring prophylaxis:

  • Cancer patients with additional risk factors for VTE who are at low bleeding risk 2
  • Long-distance travelers at increased VTE risk 2

• Patients who do NOT require routine prophylaxis:

  • Low-risk hospitalized patients 2
  • Patients with indwelling central venous catheters 2
  • Chronically immobilized persons residing at home 2

Pharmacological Prophylaxis Options

1. LMWH (First-line) 2, 1

   • Enoxaparin 40mg subcutaneously once daily
   • Dalteparin 5,000 U once daily
   • For patients >65 years: Consider enoxaparin 30mg every 12 hours

2. Unfractionated Heparin (UFH) 2

   • 5,000 U subcutaneously every 8 hours
   • Preferred for patients with severe renal impairment (CrCl <30 mL/min)

3. Fondaparinux 3

   • 2.5mg subcutaneously once daily
   • Initial dose should be given 6-8 hours after surgery if used post-operatively

Mechanical Prophylaxis

For patients who are bleeding or at high risk for major bleeding 2:

• Intermittent pneumatic compression (IPC) - preferred
• Graduated compression stockings (GCS)
• Switch to pharmacological prophylaxis when bleeding risk decreases

Duration of Prophylaxis

• Standard duration: Continue for the duration of hospitalization or until full mobility is restored 1
• Extended prophylaxis:
  • Up to 28-35 days for high-risk patients (e.g., active cancer) 1
  • For hip fracture surgery, extended prophylaxis up to 24 additional days 3

Special Populations

1. Cancer Patients:

   • LMWH is preferred over unfractionated heparin 2
   • Extended prophylaxis may be considered for outpatients receiving systemic treatment who have high VTE risk 1

2. Critically Ill Patients:

   • LMWH or LDUH with frequent assessment of bleeding risk 2, 4
   • Mechanical prophylaxis if bleeding risk is high 2

3. Renal Insufficiency:

   • Consider UFH or reduced-dose fondaparinux (1.5mg daily) 4
   • For LMWH, reduce enoxaparin to 30mg once daily if CrCl <30 mL/min 1

Common Pitfalls to Avoid

1. Inadequate risk assessment: Use validated tools like Padua score (high risk ≥4 points) or IMPROVE VTE Risk Assessment Model (increased risk ≥2 points) 1

2. Inappropriate prophylaxis duration: Not extending prophylaxis for high-risk patients or continuing unnecessarily in low-risk patients 2

3. Overlooking contraindications:

   • Active bleeding
   • Severe thrombocytopenia (platelets <25×10⁹/L)
   • Recent intracranial hemorrhage
   • Heparin-induced thrombocytopenia 1

4. Relying on IVC filters for primary prevention: Not recommended as first-line prophylaxis 1

5. Routine ultrasound screening: Not recommended for asymptomatic critically ill patients 2

By following these evidence-based recommendations, clinicians can effectively reduce the risk of DVT while minimizing bleeding complications in at-risk patients.