What is the recommended prophylaxis for Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE) in an elderly patient with a fracture?

VTE Prophylaxis in Elderly Patients with Fractures

Low molecular weight heparin (LMWH) at 30 mg enoxaparin every 12 hours is the preferred pharmacological prophylaxis for elderly patients with fractures, initiated 6-8 hours post-operatively once hemostasis is established, and should be combined with mechanical prophylaxis for maximum protection. 1

Risk Stratification

Elderly patients with fractures are at substantially elevated risk for VTE, with multiple compounding factors:

• Age >75 years is an independent risk factor for DVT 1
• Lower extremity fractures carry a 2-point risk score in validated assessment tools 1
• Additional risk factors include prolonged immobility, mechanical ventilation, severe traumatic brain injury, plasma transfusions within 24 hours, and spine injury 1
• Hip fracture patients specifically have VTE rates of 12-37% without extended prophylaxis 1

High-risk patients (based on validated scoring systems like TESS or RAP) require pharmacological prophylaxis; low-risk patients may not require it. 1

Pharmacological Prophylaxis: Agent Selection

First-Line: LMWH (Preferred)

LMWH is superior to unfractionated heparin (UFH) in elderly trauma patients, demonstrating:

• Lower incidence of DVT (P = 0.007) and PE (P < 0.001) 1
• Fewer bleeding complications and transfusions (P < 0.001) 1
• Reduced mortality (P < 0.001) 1
• Benefits are particularly evident in patients >75 years old 1

Dosing for elderly patients (>65 years):

• Enoxaparin 30 mg subcutaneously every 12 hours 1
• Dose adjustment according to anti-Xa levels and weight is warranted 1
• In renal failure: switch to UFH 5000 units every 8 hours 1

Second-Line Alternatives

Factor Xa inhibitors (rivaroxaban, apixaban) may be considered as alternatives but have demonstrated:

• Higher rates of PE compared to LMWH (adjusted rate 2% vs -3.5%) 1
• No significant differences in DVT, bleeding, or transfusion rates 1
• Potential advantages in patient compliance and preference 1
• Should only be considered after clinical stabilization 1

Fondaparinux 2.5 mg subcutaneously once daily is FDA-approved for hip fracture, hip replacement, and knee replacement surgery prophylaxis 2

Timing of Initiation

Critical timing considerations to balance thrombosis prevention with bleeding risk:

• Initiate pharmacological prophylaxis 6-8 hours post-operatively after hemostasis is established 2
• Administration earlier than 6 hours post-surgery significantly increases major bleeding risk 2
• Post-operative initiation (vs. pre-operative) decreases intraoperative bleeding complications in hip compression screw operations 1
• Pre-operative prophylaxis does not influence mortality or reoperation rates 1

Mechanical Prophylaxis

Mechanical prophylaxis should be used in conjunction with pharmacological prophylaxis for optimal protection:

• Combined mechanical and pharmacological prophylaxis reduces DVT risk by 66% (RR 0.34) 1
• Mechanical prophylaxis alone reduces DVT risk by 45% (RR 0.55) 1
• Options include intermittent pneumatic compression devices, graduated compression stockings, and early mobilization 1

When Mechanical Prophylaxis is Mandatory

Use mechanical prophylaxis alone when pharmacological prophylaxis is contraindicated:

• Active bleeding 1
• Coagulopathy 1
• Hemodynamic instability 1
• Solid organ injury 1
• Traumatic brain injury requiring stabilization 1
• Spinal trauma 1

Preoperative mechanical prophylaxis (from admission until surgery) may provide additional benefit by reducing symptomatic DVT (OR 0.28, p = 0.042) without increasing bleeding risk 3

Duration of Prophylaxis

Standard duration:

• 5-9 days for most fracture surgeries 1, 2
• Up to 10-11 days was used in clinical trials 1, 2

Extended prophylaxis for hip fracture:

• Up to 24 additional days (total 32 days including peri-operative period) is recommended 1, 2
• Risk of DVT persists for up to 2 months post-hip replacement 1
• Extended prophylaxis reduces late VTE events significantly 1

Special Populations and Contraindications

Spinal Fractures

Thromboprophylaxis is recommended for thoracolumbar fractures based on pooled spinal cord injury data 1

• VTE prophylaxis does not increase spinal hematoma risk 1
• However, extreme caution is required with neuraxial anesthesia/epidural catheters due to risk of epidural or spinal hematomas 2

Renal Impairment

Switch from LMWH to UFH in renal failure:

• UFH 5000 units every 8 hours 1
• LMWH accumulates in renal dysfunction, increasing bleeding risk 1

Efficacy Data

Pharmacological prophylaxis effectiveness:

• Reduces DVT risk by 52% overall (RR 0.48) 1
• LMWH superior to UFH with 32% additional reduction (RR 0.68) 1
• Important caveat: Neither mechanical nor pharmacological prophylaxis has been shown to significantly reduce PE rates in meta-analyses 1
• Pharmacological prophylaxis increases bleeding risk (RR 2.04) 1

Common Pitfalls to Avoid

• Do not initiate pharmacological prophylaxis before 6 hours post-surgery - significantly increases bleeding complications 2
• Do not use standard LMWH dosing in renal failure - switch to UFH to avoid accumulation 1
• Do not withhold prophylaxis based on age alone - elderly patients benefit significantly from prophylaxis 1
• Do not use mechanical prophylaxis alone when pharmacological prophylaxis is safe - combined therapy is superior 1
• Do not discontinue prophylaxis at hospital discharge for hip fracture patients - extend for total of 32 days 1, 2
• Do not forget to assess bleeding risk factors before initiating pharmacological prophylaxis 1