What is the recommended duration of anticoagulation with reduced dosing for Deep Vein Thrombosis (DVT) prophylaxis following hip hemi arthroplasty in a patient with high risk of DVT and Pulmonary Embolism (PE) but moderate to low risk of bleeding?

Duration of Anticoagulation for DVT Prophylaxis Following Hip Hemi Arthroplasty

For patients undergoing hip hemi arthroplasty (hip fracture surgery), pharmacological DVT prophylaxis should be administered for a minimum of 10-14 days, with strong consideration for extended prophylaxis up to 35 days in all patients, as hip fracture surgery confers high VTE risk that persists well beyond hospital discharge. 1, 2

Standard Duration: Minimum 10-14 Days

• All patients undergoing hip hemi arthroplasty require at least 10-14 days of pharmacological prophylaxis postoperatively, as recommended by the American College of Chest Physicians (ACCP) 3, 1, 2
• This minimum duration applies regardless of the specific anticoagulant agent selected 2
• The International Union of Angiology (IUA) guidelines support this 7-10 day minimum duration for all hip fracture surgeries 3, 2

Extended Prophylaxis: Up to 35 Days (Strongly Recommended)

Extended prophylaxis for approximately 4-5 weeks (up to 35 days total) should be strongly considered for all hip fracture patients, as VTE risk remains significantly elevated beyond hospital discharge 1, 2

Evidence Supporting Extended Duration:

• The RECORD 2 trial demonstrated that extended duration rivaroxaban (31-39 days) after hip arthroplasty was more effective than enoxaparin (10-14 days) without increased bleeding complications 3
• The SAVE-HIP3 trial showed that extended semuloparin prophylaxis (total ~30 days) reduced VTE or all-cause mortality from 18.6% to 3.9% compared to stopping at 7-10 days (OR 0.18,95% CI 0.07-0.45, P<0.001) 2
• For hip arthroplasty, treatment duration of 35 days has been validated in clinical trials 3

Preferred Pharmacological Agents with Reduced Dosing

Low Molecular Weight Heparin (LMWH) - First-Line Choice:

• Enoxaparin 40 mg subcutaneously once daily or 30 mg twice daily is the most widely used and preferred regimen 1
• LMWH should be started before surgery if surgery is delayed, or as soon as hemostasis is shown after surgery 3, 2
• LMWH demonstrates significantly lower rates of DVT, PE, bleeding complications, transfusions, and mortality compared to unfractionated heparin 2

Dose adjustments for special populations:

• Renal impairment (CrCl <30 mL/min): Reduce enoxaparin to 30 mg subcutaneously once daily 1
• Body weight >150 kg: Consider increasing to 40 mg subcutaneously every 12 hours 1
• Elderly patients (>65 years): Initial dose of enoxaparin 30 mg every 12 hours 2

Rivaroxaban - Alternative Option:

• Rivaroxaban 10 mg once daily is FDA-approved for VTE prophylaxis after hip replacement surgery 4
• Initiate 6-10 hours after surgery once hemostasis is achieved 1
• Treatment duration should be 35 days for hip arthroplasty 3
• Rivaroxaban 10 mg once daily was significantly more effective than enoxaparin 40 mg once daily for extended thromboprophylaxis (absolute risk reduction 2.6%, P<0.001) with similar safety profiles 5

Fondaparinux:

• Fondaparinux 2.5 mg subcutaneously once daily is an effective alternative 1
• Reduced dose of 1.5 mg daily for patients with renal impairment (CrCl 30-50 mL/min) 1
• Initiate 6-8 hours after surgery once hemostasis is established 1

High-Risk Patients Requiring Extended Prophylaxis

All hip fracture patients should be considered high-risk and receive extended prophylaxis, with particular attention to those with: 2

• History of previous VTE
• Active cancer
• Limited mobility
• Age >75 years
• Prolonged ICU or hospital length of stay

Adjunctive Mechanical Prophylaxis

• Intermittent pneumatic compression (IPC) devices should be used in addition to pharmacological prophylaxis for a goal of 18 hours daily 1
• Combined mechanical and pharmacological prophylaxis achieves a 66% reduction in DVT risk compared to either modality alone 2
• For patients at high risk of bleeding, mechanical prophylaxis with IPC may be used alone until bleeding risk diminishes 1, 2

Critical Contraindications and Timing Considerations

Delay pharmacological prophylaxis in the presence of: 2

• Active bleeding
• Coagulopathy
• Hemodynamic instability
• Traumatic brain injury
• Spinal trauma

Use mechanical prophylaxis alone until stabilization occurs in these cases 2

Neuraxial Anesthesia Considerations:

• For patients requiring epidural or spinal anesthesia, enoxaparin should be held for 24 hours before catheter manipulation and resumed no earlier than 2 hours after catheter removal 1
• LMWH timing must be carefully coordinated with neuraxial anesthesia to minimize bleeding risk 2

Common Pitfalls to Avoid

• Do not use aspirin as sole therapy for DVT prophylaxis - the ACCP explicitly recommends against this practice 3, 2
• Do not rely on mechanical prophylaxis alone except when pharmacological agents are contraindicated 2
• Do not fail to extend prophylaxis beyond hospital discharge - approximately 42-58% of at-risk patients do not receive appropriate extended VTE prophylaxis despite clear guidelines 1
• Do not forget to adjust for renal function - failure to do so can lead to bleeding complications, particularly with renally-cleared agents 2
• Do not use LMWH or fondaparinux in severe renal impairment (CrCl <30 mL/min) - switch to unfractionated heparin 5000 units subcutaneously every 8 hours instead 2

Bleeding Risk Monitoring

• Major bleeding with LMWH occurs in approximately 1.0-1.4% of hip fracture patients 2
• LMWH demonstrates fewer bleeding complications compared to unfractionated heparin (P<0.001) 2
• Regular assessment for signs and symptoms of DVT/PE should be performed throughout the prophylaxis period 2