What are the guidelines for Deep Vein Thrombosis (DVT) prophylaxis?

DVT Prophylaxis Guidelines

All hospitalized patients should undergo risk assessment for VTE using validated tools, with pharmacologic prophylaxis (preferably LMWH) recommended for acutely ill medical patients and all surgical patients unless bleeding risk is high, in which case intermittent pneumatic compression devices should be used. 1

Risk Assessment

• Use validated risk assessment models to stratify patients upon hospital admission 2, 1
• The Padua VTE Risk Assessment Model (score ≥4 indicates high risk) is recommended for medical patients 2
• The IMPROVE VTE Risk Assessment Model (score ≥2 indicates increased risk) provides an alternative validated approach 2
• Assess bleeding risk concurrently using tools like the IMPROVE bleeding RAM (score ≥7 indicates high bleeding risk) 2

Key risk factors include: older age (>60-70 years), active malignancy, previous VTE, reduced mobility, recent surgery/trauma, obesity, thrombophilia, heart/respiratory failure, and acute infection 2

Hospitalized Medical Patients

Pharmacologic Prophylaxis

• Acutely ill hospitalized medical patients with active malignancy, acute medical illness, or reduced mobility should receive pharmacologic thromboprophylaxis unless contraindicated 2, 1
• LMWH is the preferred agent over unfractionated heparin (UFH) or direct oral anticoagulants (DOACs) 2, 1
• Standard dosing: enoxaparin 40 mg subcutaneously once daily 1, 3
• Continue prophylaxis for minimum 7 days and until patient is fully mobile 1
• Do NOT use extended-duration outpatient prophylaxis beyond hospitalization for medical patients—this is a strong recommendation against the practice 2

When Pharmacologic Prophylaxis is Contraindicated

• Use intermittent pneumatic compression (IPC) devices when bleeding risk is high 2, 1
• Do NOT use graduated compression stockings alone—they are ineffective and cause skin damage 2
• The American College of Physicians specifically recommends against graduated compression stockings for VTE prevention 2

Surgical Patients

Standard Surgical Prophylaxis

• All patients undergoing major surgery (>30 minutes) should receive pharmacologic prophylaxis unless contraindicated 1, 3
• Begin prophylaxis preoperatively and continue for at least 7-10 days postoperatively 2, 3
• LMWH (enoxaparin 40 mg daily) is first-line for most surgical patients 1, 3

Extended Prophylaxis for High-Risk Surgery

• Patients undergoing major abdominal or pelvic surgery should receive extended prophylaxis up to 4 weeks 2, 1, 3
• Cancer surgery patients require extended LMWH prophylaxis for up to 4 weeks postoperatively 2, 1
• High-risk surgical patients with cancer should receive combination therapy: LMWH plus intermittent pneumatic compression devices 1

Cancer Patients

Hospitalized Cancer Patients

• Hospitalized patients with active malignancy and acute medical illness or reduced mobility should receive pharmacologic thromboprophylaxis 2
• Hospitalized patients with active malignancy without additional risk factors may be offered prophylaxis based on individual assessment 2

Ambulatory Cancer Patients

• Do NOT routinely provide thromboprophylaxis to all ambulatory cancer patients receiving chemotherapy 2
• Selected high-risk outpatients may receive prophylaxis with apixaban, rivaroxaban, or LMWH 2
• Specifically consider prophylaxis for patients receiving highly thrombogenic therapies (thalidomide, lenalidomide-based regimens) 2, 1

The 2020 ASCO guidelines added DOACs (apixaban and rivaroxaban) as options for ambulatory cancer patients, but note that rivaroxaban and edoxaban carry higher bleeding risk in patients with GI and potentially genitourinary cancers 2

Choice of Anticoagulant Agent

First-Line Agents

• LMWH is preferred over DOACs for VTE prophylaxis in hospitalized medical patients 2, 1
• LMWH is preferred over UFH due to once-daily dosing and lower risk of heparin-induced thrombocytopenia 1, 3

Special Populations

• Severe renal impairment (CrCl <30 mL/min): Use UFH instead of LMWH, or reduce enoxaparin to 30 mg once daily 1, 3
• Heparin-induced thrombocytopenia: Use fondaparinux as alternative 1
• Patients already on DOACs for other indications: Existing DOAC therapy may suffice 2

DOAC Dosing for Prophylaxis (When Used)

• Rivaroxaban: 10 mg once daily with or without food for acutely ill medical patients 4
• Duration: 31-39 days total (in hospital and after discharge) for acutely ill medical patients at risk but not at high bleeding risk 4

Mechanical Prophylaxis

When to Use Mechanical Methods

• Use when pharmacologic prophylaxis is contraindicated due to active bleeding or high bleeding risk 2, 1, 3
• Consider combination therapy (pharmacologic plus mechanical) for very high-risk patients 1, 3

Device Selection

• Intermittent pneumatic compression (IPC) devices are preferred over graduated compression stockings 2, 1
• Graduated compression stockings are NOT recommended as standalone prophylaxis—they are ineffective and cause skin damage 2
• For long-distance travelers at increased VTE risk, graduated compression stockings (15-30 mmHg below-knee) may be used 1

Common Pitfalls and Contraindications

Avoid These Practices

• Do NOT provide universal prophylaxis to all medical patients regardless of risk—this increases bleeding without proportional benefit 2
• Do NOT extend prophylaxis beyond hospitalization for medical patients—strong evidence against this practice 2
• Do NOT use graduated compression stockings as primary prophylaxis—they don't prevent PE or reduce mortality 2

Absolute Contraindications to Pharmacologic Prophylaxis

• Active pathological bleeding 4
• Severe hypersensitivity to anticoagulant 4
• High bleeding risk (IMPROVE bleeding score ≥7) 2

Important Warnings

• Spinal/epidural hematoma risk: Patients receiving neuraxial anesthesia or spinal puncture while on anticoagulation face risk of permanent paralysis 4
• Premature discontinuation increases thrombotic risk: Consider bridging with another anticoagulant if stopping therapy 4
• Pregnancy-related hemorrhage: Use anticoagulation cautiously in pregnant women 4

Implementation Gap

Despite clear guidelines, only 39.5% of at-risk medical patients receive appropriate prophylaxis compared to 58.5% of surgical patients 2. Implementation of systematic risk assessment and prophylaxis protocols significantly improves compliance and reduces VTE events 2. Healthcare systems should implement mandatory risk assessment tools and decision support to close this evidence-practice gap 2.