What types of prophylaxis are recommended for patients at risk of Deep Vein Thrombosis (DVT)?

Types of DVT Prophylaxis

DVT prophylaxis consists of two main categories: pharmacological anticoagulation and mechanical methods, with the choice determined primarily by bleeding risk and thrombosis risk stratification. 1, 2

Pharmacological Prophylaxis Options

First-Line Agents

Low-molecular-weight heparin (LMWH) is the preferred first-line pharmacological agent for most patients requiring DVT prophylaxis. 1, 2 The standard dosing regimens include:

• Enoxaparin 40 mg subcutaneously once daily 1, 2
• Dalteparin 5000 IU subcutaneously once daily 1

Unfractionated heparin (UFH) 5000 units subcutaneously twice or three times daily is an equally effective alternative to LMWH. 1, 2 The choice between LMWH and UFH should be based on once-daily versus multiple daily dosing convenience, renal function, and local formulary costs, as efficacy is equivalent. 2

Fondaparinux 2.5 mg subcutaneously once daily is another first-line option with equivalent efficacy. 1, 2

Newer Oral Anticoagulants

For specific surgical populations, newer oral anticoagulants are FDA-approved:

• Rivaroxaban 10 mg once daily is approved for VTE prophylaxis following hip or knee replacement surgery and for acutely ill medical patients (starting 6-10 hours postoperatively). 1, 3
• Apixaban is approved for prophylaxis following hip or knee replacement surgery. 4
• Dabigatran is mentioned as an option for major orthopedic surgery. 1

However, rivaroxaban is not recommended for routine VTE prevention in acutely ill general medical patients based on the MAGELLAN trial, which showed increased bleeding risk despite fewer VTE events. 1

Special Dosing Considerations

For renal impairment: 2

• Fondaparinux should be reduced to 1.5 mg once daily if creatinine clearance is 30-50 mL/min
• Enoxaparin should be reduced to 30 mg once daily if creatinine clearance is <30 mL/min

For obesity (>150 kg): Consider increasing enoxaparin to 40 mg subcutaneously every 12 hours. 2

Mechanical Prophylaxis Options

Mechanical methods work by counteracting venous stasis and include: 1, 5

Intermittent Pneumatic Compression (IPC)

IPC devices are the preferred mechanical method, with a goal of 18 hours daily application. 1 They significantly reduce the odds of proximal DVT compared to no prophylaxis. 1

Graduated Compression Stockings (GCS)

GCS (15-30 mm Hg below-knee) provide additional protection and are most effective when combined with other preventive therapies. 1 However, they should not be used as monotherapy when pharmacological prophylaxis is feasible. 1

A-V Foot Pumps

These are an alternative mechanical option, though less commonly used than IPC. 6

Risk-Stratified Approach to Prophylaxis Selection

High Thrombosis Risk, Low Bleeding Risk

Combination of pharmacological and mechanical prophylaxis is recommended. 1 This approach is particularly important for:

• Major orthopedic surgery patients 1
• Thoracic surgery patients with moderate-to-high VTE risk 1
• Cancer surgery patients at high thrombosis risk 1

High Bleeding Risk

Use mechanical prophylaxis alone (IPC or GCS) until bleeding risk diminishes, then add pharmacological prophylaxis. 1, 2 Absolute contraindications to pharmacological prophylaxis include: 2

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

Low-to-Moderate Thrombosis Risk

Pharmacological prophylaxis alone with LMWH, UFH, or fondaparinux is appropriate. 1, 2

Duration of Prophylaxis

Surgical Patients

Standard duration is 7-10 days postoperatively for most surgical patients. 1, 2

Extended prophylaxis for up to 4 weeks (28-35 days total) is strongly recommended for: 1, 2

• Major abdominal or pelvic surgery for cancer
• Hip fracture surgery
• Patients with restricted mobility, obesity, or history of VTE

LMWH should be initiated at least 12 hours from the time of surgery (either pre- or postoperatively). 1

Medical Patients

Pharmacological prophylaxis should be continued throughout hospitalization for acutely ill medical patients. 1, 2 However, routine continuation beyond hospital discharge is not recommended unless the patient is an ambulatory cancer patient receiving systemic therapy at high risk for thrombosis. 1

Special Population Considerations

Cancer Patients

Cancer patients undergoing surgery should receive at least 4 weeks of LMWH prophylaxis. 1 For ambulatory cancer patients on chemotherapy with Khorana score ≥2, primary prophylaxis is recommended. 2

Multiple myeloma patients receiving thalidomide or lenalidomide with chemotherapy/dexamethasone require prophylaxis with either aspirin (lower-risk) or LMWH (higher-risk). 1

Trauma Patients

Both mechanical and pharmacologic prophylaxis should be used unless contraindicated. 1, 6 Inferior vena cava filters are not routinely recommended for primary VTE prevention in major trauma patients. 1

Spinal Surgery

Once hemostasis is achieved and bleeding risk decreases, add pharmacologic prophylaxis to IPC for high-risk VTE patients. 1

Critical Pitfalls to Avoid

Do not use mechanical prophylaxis as monotherapy when pharmacological prophylaxis is feasible, as mechanical methods alone have not been shown to prevent fatal postoperative pulmonary embolism. 1, 5

Do not use aspirin as sole prophylaxis except in specific populations (multiple myeloma patients at lower risk, or long-distance travelers when LMWH/stockings unavailable). 1

Ensure proper application and continuous use of mechanical devices, as improper use significantly reduces efficacy. 1

Avoid neuraxial procedures in patients receiving anticoagulation due to risk of epidural or spinal hematomas causing permanent paralysis. 2