DVT Prophylaxis for Adult Inpatients
Risk Stratification Is Mandatory
All hospitalized medical inpatients should undergo formal VTE risk assessment using validated tools—specifically the Padua Prediction Score or IMPROVE VTE score—to determine whether pharmacologic prophylaxis is indicated. 1
- High-risk patients (Padua score ≥4 or IMPROVE VTE score ≥2) have an 11% VTE incidence without prophylaxis versus 2.2% with prophylaxis and should receive pharmacologic thromboprophylaxis. 2, 1
- Low-risk patients (Padua score <4) have only a 0.3% VTE incidence and should not receive routine pharmacologic prophylaxis. 2
Key VTE Risk Factors That Trigger Prophylaxis
- Age >60 years 1
- Previous VTE 1
- Active malignancy 1
- Acute infection or pneumonia 1
- Immobility or acute paresis 1
- Critical illness requiring ICU care 1
- Known thrombophilia 1
Bleeding Risk Assessment Must Be Performed Concurrently
Use the IMPROVE bleeding RAM to identify patients at increased bleeding risk: 1
- Age ≥65 years 1
- Renal failure (creatinine clearance <30 mL/min) 1
- Thrombocytopenia (platelet count <50 × 10⁹/L) 1, 3
- Active gastroduodenal ulcers 1
- Hepatic disease 1
- Recent major bleeding within 3 months 1
Pharmacologic Prophylaxis: Drug Selection and Dosing
For high-risk medical inpatients without contraindications, LMWH or fondaparinux is preferred over unfractionated heparin. 1
Standard Dosing Regimens
| Agent | Standard Dose | Preference Level |
|---|---|---|
| Enoxaparin (LMWH) | 40 mg subcutaneously once daily | Preferred [4] |
| Dalteparin (LMWH) | 5,000 IU subcutaneously once daily | Preferred [4] |
| Fondaparinux | 2.5 mg subcutaneously once daily | Preferred [4] |
| Unfractionated heparin | 5,000 units subcutaneously every 8 hours (three times daily) | Alternative [4] |
LMWH is favored over UFH because it requires only once-daily dosing, has lower risk of heparin-induced thrombocytopenia, and provides more predictable anticoagulation. 1, 4
Dose Adjustments for Renal Impairment
Renal function must be assessed before initiating LMWH or fondaparinux, as both are renally cleared. 4
Specific Adjustments by Creatinine Clearance
- CrCl 30–50 mL/min: Reduce fondaparinux to 1.5 mg subcutaneously once daily. 4
- CrCl <30 mL/min:
Dose Adjustments for Extremes of Body Weight
- Patients >150 kg: Consider increasing enoxaparin to 40 mg subcutaneously every 12 hours (twice daily). 4
- Patients <50 kg: Use standard dosing; no routine reduction is required unless bleeding risk is elevated. 1
Mechanical Prophylaxis When Pharmacologic Agents Are Contraindicated
For patients with active bleeding, severe thrombocytopenia (platelet count <50 × 10⁹/L), or recent neurosurgery, use mechanical prophylaxis instead of pharmacologic agents. 1, 3
Preferred Mechanical Method
- Intermittent pneumatic compression (IPC) devices are the preferred mechanical method and should be applied within 24 hours of admission. 4, 3
- Graduated compression stockings are NOT recommended as they have not demonstrated reduction in pulmonary embolism-related mortality and may cause harm. 4
Duration of Prophylaxis
Pharmacologic prophylaxis should be continued throughout the entire hospitalization or period of immobilization. 4, 3
- Do NOT extend prophylaxis beyond hospital discharge for general medical inpatients, as the American Society of Hematology strongly recommends against this practice. 1, 3
- Exception: Extended prophylaxis (up to 4 weeks) is indicated only for specific high-risk surgical populations such as major cancer surgery or hip fracture surgery. 4
Timing of Initiation
Pharmacologic prophylaxis should be initiated immediately upon hospital admission or as soon as VTE risk is identified, provided there are no active bleeding contraindications. 4
- For trauma patients, initiate within 24 hours after bleeding control is achieved. 4
- For critically ill ICU patients, start prophylaxis immediately upon ICU admission. 4
Special Populations
Critically Ill ICU Patients
All critically ill ICU patients should receive pharmacologic prophylaxis with LMWH or UFH unless actively bleeding. 4
- Enoxaparin 40 mg subcutaneously once daily or UFH 5,000 units subcutaneously every 8 hours. 4
- Combine pharmacologic prophylaxis with IPC devices for patients at very high VTE risk (e.g., immobile, septic, multiply injured). 4
Cancer Patients
All hospitalized cancer patients with acute medical illness or reduced mobility should receive prophylactic anticoagulation unless contraindicated by bleeding risk. 4, 3
- LMWH is the preferred agent for cancer patients. 4
Chronically Ill Patients in Long-Term Care Facilities
Do NOT use routine VTE prophylaxis in chronically ill medical patients in nursing homes or transitional care units. 5
- Exception: If the patient develops acute medical illness (e.g., infection, heart failure exacerbation, respiratory failure), reassess and initiate prophylaxis using standard acute medical patient criteria. 5
Agents to Avoid
Direct oral anticoagulants (DOACs) should NOT be used for in-hospital VTE prophylaxis due to drug-drug interaction risk, hemodynamic instability, and high incidence of acute kidney injury in hospitalized patients. 4
Therapeutic-dose anticoagulation should NOT be used for primary prophylaxis in the absence of confirmed VTE, as it increases bleeding without proven benefit. 4
Critical Pitfalls to Avoid
- Do not delay mechanical prophylaxis when pharmacologic agents are contraindicated; early IPC application is essential. 4
- Do not use graduated compression stockings alone as they lack evidence for preventing fatal PE. 4
- Do not overlook daily reassessment of both VTE and bleeding risks, especially in critically ill patients. 4
- Do not continue prophylaxis beyond hospital discharge for general medical inpatients, as this increases bleeding risk without proven VTE benefit. 1, 3
- Do not use LMWH or fondaparinux without checking renal function, as accumulation in renal impairment significantly increases bleeding risk. 4