Factors to Prevent Deep Vein Thrombosis (DVT)
The most critical factor in preventing DVT is accurate risk stratification followed by appropriate prophylaxis: pharmacologic anticoagulation (LMWH, LDUH, or fondaparinux) for hospitalized medical and surgical patients at increased thrombotic risk, mechanical prophylaxis (graduated compression stockings or intermittent pneumatic compression) when bleeding risk is high, and early mobilization for low-risk patients. 1, 2
Risk Assessment and Stratification
The foundation of DVT prevention is identifying which patients require prophylaxis based on their thrombotic and bleeding risk profiles.
Patient-specific risk factors that increase DVT risk include: 2
- Age >60 years
- Active malignancy
- Previous history of VTE
- Obesity (severe)
- Restricted mobility or immobilization
- Smoking
- Pregnancy
- Estrogen use
- Known thrombophilic disorder
- Recent surgery or trauma
Procedure-related factors also determine risk level, with major surgical procedures and prolonged immobilization conferring higher risk. 2
Pharmacologic Prophylaxis
Hospitalized Medical Patients
For acutely ill hospitalized medical patients at increased risk of thrombosis, use anticoagulant thromboprophylaxis with LMWH, LDUH (twice or three times daily), or fondaparinux. 1 The choice among these agents should be based on patient preference, ease of administration (daily versus multiple daily dosing), and local acquisition costs. 1
Standard dosing for enoxaparin is 40 mg subcutaneously once daily, with dose reduction to 30 mg once daily for patients with creatinine clearance <30 mL/min. 2
For acutely ill hospitalized medical patients at LOW risk of thrombosis, do NOT use pharmacologic or mechanical prophylaxis. 1 This is a strong recommendation to avoid unnecessary bleeding complications.
Duration of prophylaxis should NOT extend beyond the period of patient immobilization or acute hospital stay. 1 Extended prophylaxis in medical patients is not recommended. 1
Critically Ill Patients
For critically ill patients, use LMWH or LDUH thromboprophylaxis over no prophylaxis. 1
Surgical Patients
All patients undergoing major surgical procedures should receive prophylaxis, beginning preoperatively when appropriate and continuing for at least 7-10 days postoperatively. 2
Extended prophylaxis up to 4 weeks should be considered for high-risk patients undergoing major abdominal or pelvic surgery. 2 This is particularly important in cancer surgery patients. 3
For procedures estimated to last <60 minutes, use 300 units/kg of heparin sodium; for procedures >60 minutes, use 400 units/kg. 4
Cancer Patients
For outpatients with solid tumors who have additional risk factors for VTE (previous VTE, immobilization, hormonal therapy, angiogenesis inhibitors, thalidomide, lenalidomide) and who are at low risk of bleeding, use prophylactic-dose LMWH or LDUH. 1
For cancer outpatients with indwelling central venous catheters, do NOT use routine prophylaxis with LMWH, LDUH, or vitamin K antagonists. 1
Mechanical Prophylaxis
When to Use Mechanical Methods
For acutely ill hospitalized medical patients at increased risk of thrombosis who are bleeding or at high risk for major bleeding, use mechanical thromboprophylaxis with graduated compression stockings (GCS) or intermittent pneumatic compression (IPC) rather than no prophylaxis. 1 When bleeding risk decreases and VTE risk persists, substitute pharmacologic prophylaxis for mechanical prophylaxis. 1
For critically ill patients who are bleeding or at high risk for major bleeding, use mechanical thromboprophylaxis with GCS or IPC until bleeding risk decreases. 1 Then transition to pharmacologic prophylaxis. 1
Mechanical Prophylaxis Options
Intermittent pneumatic compression devices and graduated compression stockings are equally effective when pharmacologic prophylaxis is contraindicated. 2, 5 Both can be used in combination with pharmacologic methods for very high-risk patients. 2
Early ambulation is recommended for low-risk patients and should be implemented as a basic measure in all patients when feasible. 2, 3
Special Populations
Long-Distance Travelers
For long-distance travelers at increased risk of VTE (previous VTE, recent surgery/trauma, active malignancy, pregnancy, estrogen use, advanced age, limited mobility, severe obesity, thrombophilic disorder), recommend frequent ambulation, calf muscle exercise, or sitting in an aisle seat. 1
For high-risk long-distance travelers, use properly fitted below-knee GCS providing 15-30 mm Hg pressure at the ankle during travel. 1 For all other travelers, do not use GCS. 1
Do NOT use aspirin or anticoagulants for long-distance travelers to prevent VTE. 1
Chronically Immobilized Patients
For chronically immobilized persons residing at home or in nursing homes, do NOT use routine thromboprophylaxis. 1
Asymptomatic Thrombophilia
For persons with asymptomatic thrombophilia (without previous VTE history), do NOT use long-term daily mechanical or pharmacologic thromboprophylaxis. 1
Common Pitfalls and Caveats
Do NOT routinely screen critically ill patients with ultrasound for DVT. 1 This is not recommended as a preventive strategy.
Avoid overuse of pharmacologic prophylaxis in low-risk patients, as this increases bleeding complications without meaningful benefit. 6, 7 The risk-benefit ratio must favor prophylaxis based on individual thrombotic risk.
Be aware that graduated compression stockings in combination with pharmacologic prophylaxis have uncertain additional benefit, and recent evidence suggests they may not provide added value beyond pharmacologic prophylaxis alone. 3
Patients particularly averse to skin complications, cost, and clinical monitoring requirements of mechanical prophylaxis are likely to decline these interventions. 1 This should be discussed when bleeding risk mandates mechanical-only prophylaxis.
For procedures with high bleeding risk (such as TURP), mechanical prophylaxis should be used instead of pharmacologic methods, as limited data suggest greater blood loss and higher transfusion rates with LDUH in these patients. 7