When should prophylaxis be given to prevent deep vein thrombosis (DVT) in hospitalized patients?

When to Give DVT Prophylaxis in Hospitalized Patients

Hospitalized medical patients at increased risk of thrombosis should receive pharmacologic prophylaxis with LMWH, low-dose unfractionated heparin (bid or tid), or fondaparinux, unless they are actively bleeding or at high risk for major bleeding. 1

Risk Stratification Framework

High-Risk Patients Requiring Prophylaxis

• Acutely ill hospitalized medical patients with reduced mobility or acute medical illness (heart failure, respiratory insufficiency, infection) should receive anticoagulant thromboprophylaxis 1
• Critically ill patients (including ventilated patients) should receive LMWH or LDUH prophylaxis 1, 2
• Hospitalized cancer patients with active malignancy and acute medical illness or reduced mobility should be offered pharmacologic thromboprophylaxis 1
• Patients with Padua score ≥4 (indicating 11% VTE risk without prophylaxis) or IMPROVE VTE score ≥2 warrant prophylaxis 3

Low-Risk Patients Who Should NOT Receive Prophylaxis

• Acutely ill hospitalized medical patients at low risk of thrombosis should not receive pharmacologic or mechanical prophylaxis 1
• Patients admitted solely for minor procedures or chemotherapy infusion should not receive routine prophylaxis 1
• Chronically immobilized persons at home or nursing homes should not receive routine thromboprophylaxis 1

Absolute Contraindications to Pharmacologic Prophylaxis

Do not give anticoagulant prophylaxis to patients who are:

• Actively bleeding or at high risk for major bleeding 1
• Platelet count <50,000/mcL 3
• Recent intracranial hemorrhage or neurosurgery 2, 3

Alternative Prophylaxis for High Bleeding Risk

For patients at increased VTE risk who are bleeding or at high bleeding risk, use mechanical prophylaxis:

• Intermittent pneumatic compression (IPC) is preferred over graduated compression stockings 1, 3
• Graduated compression stockings (15-30 mmHg) are an alternative option 1, 3
• When bleeding risk decreases, switch from mechanical to pharmacologic prophylaxis 1

Pharmacologic Agent Selection

Recommended first-line agents (all have Grade 1B evidence):

• Low-molecular-weight heparin (LMWH) - preferred in critically ill patients 1, 2
• Low-dose unfractionated heparin (LDUH) - 5,000 units subcutaneously bid or tid 1
• Fondaparinux - 2.5 mg subcutaneously once daily 1, 4

Agent selection should be based on:

• Patient preference and compliance 1
• Renal function (UFH preferred if severe renal impairment) 2
• Ease of administration (daily vs bid vs tid dosing) 1
• Local formulary costs 1

Duration of Prophylaxis

Prophylaxis should be continued throughout the period of immobilization or acute hospital stay, but NOT extended beyond hospital discharge 1, 3. This strong recommendation is based on:

• Extended prophylaxis beyond discharge did not reduce symptomatic DVT/PE in medical patients 1
• Higher incidence of major bleeding (3.9% vs 1.9%) and all-cause mortality with extended prophylaxis 5

Exception for Surgical Patients

• Major cancer surgery patients: Continue prophylaxis for at least 7-10 days, with extended prophylaxis up to 4 weeks for high-risk patients 1
• Hip fracture surgery: Extended prophylaxis up to 24 additional days (32 days total) is recommended 4

Special Populations

Cancer Patients (Outpatient)

• High-risk outpatients (Khorana score ≥2) may receive prophylaxis with apixaban, rivaroxaban, or LMWH after discussion of risks/benefits 1
• Multiple myeloma patients on thalidomide/lenalidomide regimens: Use aspirin (lower-risk) or LMWH (higher-risk) 1
• Cancer patients with central venous catheters: Do NOT give routine prophylaxis 1

Long-Distance Travelers

• Travelers at increased VTE risk (previous VTE, recent surgery, active malignancy, pregnancy, estrogen use, advanced age, limited mobility, severe obesity, thrombophilia) should use 15-30 mmHg below-knee compression stockings plus frequent ambulation 1
• Average-risk travelers: Do NOT use compression stockings 1

Common Pitfalls to Avoid

• Do not start prophylaxis earlier than 6-8 hours after surgery - this significantly increases major bleeding risk 4
• Do not routinely extend prophylaxis beyond hospital discharge in medical patients - this increases bleeding and mortality without reducing VTE 1, 5
• Do not use graduated compression stockings alone for VTE prophylaxis in hospitalized patients - they are not recommended as sole prophylaxis 1, 6
• Do not give prophylaxis to low-risk patients - this exposes them to bleeding risk without benefit 1