What is the recommended prophylaxis for patients at risk of Deep Vein Thrombosis (DVT)?

DVT Prophylaxis Recommendations

For hospitalized medical patients at increased risk of thrombosis, use pharmacologic prophylaxis with LMWH (enoxaparin 40 mg subcutaneously once daily), low-dose unfractionated heparin (5000 units twice or three times daily), or fondaparinux (2.5 mg subcutaneously once daily) throughout hospitalization. 1

Risk Stratification

High-Risk Medical Patients Requiring Prophylaxis

• Acutely ill hospitalized patients with reduced mobility 1
• Patients with active malignancy 1
• History of prior VTE (increases risk approximately six-fold) 2
• Congestive heart failure, acute respiratory insufficiency, acute infectious/inflammatory diseases 3
• Cancer patients hospitalized with neutropenia and presumed infection 1

Low-Risk Patients (No Prophylaxis Needed)

• Hospitalized medical patients at low risk of thrombosis should NOT receive pharmacologic or mechanical prophylaxis 1

Pharmacologic Prophylaxis Options

First-Line Agents (Choose One)

• LMWH (Preferred): Enoxaparin 40 mg subcutaneously once daily 1, 4
• Unfractionated Heparin: 5000 units subcutaneously twice or three times daily 1
• Fondaparinux: 2.5 mg subcutaneously once daily 1, 5

The choice between these agents should be based on once-daily versus multiple daily dosing convenience, renal function, and local formulary costs, as efficacy is equivalent. 1, 6

Renal Impairment Dosing

• Fondaparinux: Reduce to 1.5 mg once daily if creatinine clearance 30-50 mL/min 1, 3
• Enoxaparin: Reduce to 30 mg once daily if creatinine clearance <30 mL/min 2

Obesity Considerations

• For patients >150 kg, consider increasing enoxaparin to 40 mg subcutaneously every 12 hours 2

Surgical Patients

Perioperative Timing

• Initial dose: Administer no earlier than 6-8 hours after surgery once hemostasis is established 5
• Critical warning: Administration earlier than 6 hours after surgery significantly increases major bleeding risk 5

Standard Duration

• Continue for 7-10 days postoperatively for most surgical patients 1, 2
• Use highest prophylactic dose of LMWH in high-risk surgical patients 1, 2

Extended Prophylaxis (4 Weeks Total)

Extended prophylaxis is strongly recommended for: 1, 2

• Major abdominal or pelvic surgery (laparotomy or laparoscopy)
• Hip fracture surgery (up to 24 additional days beyond initial 7-10 days) 5
• Cancer surgery patients
• Patients with restricted mobility, obesity, or history of VTE

Do NOT use extended prophylaxis if high bleeding risk is present. 1

High Bleeding Risk Patients

Mechanical Prophylaxis Only

For patients actively bleeding or at high risk for major bleeding: 1

• Use graduated compression stockings (15-30 mm Hg at ankle) 1
• OR intermittent pneumatic compression devices 1
• Do NOT use anticoagulant prophylaxis 1

Transition Strategy

• When bleeding risk decreases and VTE risk persists, substitute pharmacologic for mechanical prophylaxis 1

Combined Approach for Highest Risk

• Use both mechanical AND pharmacologic prophylaxis in highest-risk patients (e.g., cancer surgery with history of VTE) 1, 2
• Mechanical methods should NOT be used as monotherapy unless pharmacologic methods are contraindicated 1, 2

Cancer-Specific Considerations

Hospitalized Cancer Patients

• Use same prophylaxis as general medical patients (LMWH, UFH, or fondaparinux) throughout hospitalization 1
• Patients admitted solely for chemotherapy or minor procedures do NOT require routine prophylaxis 1

Ambulatory Cancer Patients

Primary prophylaxis is recommended for: 1

• Locally advanced or metastatic pancreatic cancer receiving chemotherapy (use LMWH or direct oral anticoagulants like rivaroxaban/apixaban) 1
• Patients with Khorana score ≥2 receiving systemic therapy (use rivaroxaban or apixaban) 1
• Myeloma patients on immunomodulatory drugs with steroids (use LMWH, low-dose aspirin 100 mg daily, or apixaban) 1

Do NOT use routine prophylaxis for: 1

• Lung cancer patients (outside clinical trials)
• Patients with indwelling central venous catheters 1

Duration of Prophylaxis

Standard Duration

• Continue throughout hospitalization or period of immobilization 1
• Typically 6-14 days for medical patients 3

Do NOT Extend Beyond Hospitalization

• For acutely ill medical patients, do NOT extend prophylaxis beyond hospital discharge or acute immobilization period 1
• Exception: Extended prophylaxis after major cancer surgery as noted above 1, 2

Critical Contraindications and Warnings

Neuraxial Anesthesia Warning

Epidural or spinal hematomas may occur with anticoagulation and neuraxial procedures, potentially causing permanent paralysis. 5

Risk factors include: 5

• Indwelling epidural catheters
• Concomitant NSAIDs, antiplatelet agents, or other anticoagulants
• History of traumatic/repeated epidural or spinal puncture
• Spinal deformity or prior spinal surgery

Absolute Contraindications to Pharmacologic Prophylaxis

• Active bleeding 1
• Severe thrombocytopenia (platelet count <50,000/μL) 1
• Active intracranial bleeding in CNS malignancy patients 1
• Recent neurosurgery 1

Common Pitfalls to Avoid

1. Underprophylaxis: Only 58.5% of at-risk surgical patients and 39.5% of at-risk medical patients receive recommended prophylaxis despite clear guidelines 1

2. Inadequate duration: Failing to provide extended prophylaxis (4 weeks) after major abdominal/pelvic cancer surgery when indicated 1, 2

3. Premature postoperative dosing: Administering anticoagulation <6 hours after surgery significantly increases bleeding risk 5

4. Mechanical prophylaxis alone in appropriate candidates: Using only compression devices when pharmacologic prophylaxis is not contraindicated 1, 2

5. Ignoring renal function: Not adjusting LMWH or fondaparinux doses for creatinine clearance <30-50 mL/min 1, 2, 3

6. Underestimating prior DVT risk: History of provoked DVT still increases postoperative risk six-fold and requires aggressive prophylaxis 2