# Venous Thromboembolism Prevention and Management in Rehabilitation

## Introduction

**Venous thromboembolism (VTE)**, encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE), is a major complication in rehabilitation populations. Patients with **spinal cord injury, stroke, traumatic brain injury**, and major orthopedic conditions are at particularly high risk due to immobility, venous stasis, and hypercoagulability. Physiatrists must be proficient in risk stratification, prophylaxis, diagnosis, and management of VTE throughout the rehabilitation course.

## Epidemiology and Risk Factors

### Incidence in Rehabilitation Populations

**Spinal cord injury**: DVT incidence 40-80% without prophylaxis; highest risk in first 2 weeks. **Stroke**: DVT in 20-50% of hemiplegic limbs without prophylaxis. **TBI**: VTE incidence 20-30% depending on injury severity. **Hip and knee arthroplasty**: DVT 40-60% without prophylaxis. **Hip fracture**: Among the highest VTE risk surgical populations.

### Virchow Triad in Rehabilitation

**Venous stasis**: Immobility, paralysis, prolonged bed rest. **Endothelial injury**: Surgical trauma, central venous catheters, fractures. **Hypercoagulability**: Acute illness, inflammation, malignancy, hormonal factors. Additional risk factors: Age >60, obesity, prior VTE, cancer, inherited thrombophilia.

### VTE Risk Assessment

Identify patient-specific and condition-specific risk factors at admission. No single validated risk assessment tool specific to rehabilitation populations. **Caprini score** used in surgical populations; less validated in rehabilitation. Clinical vigilance essential, particularly during the first 2-4 weeks.

![Virchow triad applied to rehabilitation populations with specific risk factors](images/virchow-triad-rehabilitation.png)

## Prophylaxis

### Pharmacologic Prophylaxis

**Low-molecular-weight heparin (LMWH)**: Enoxaparin 40 mg SQ daily (preferred in most settings). **Unfractionated heparin (UFH)**: 5,000 units SQ every 8-12 hours. **Direct oral anticoagulants (DOACs)**: Rivaroxaban, apixaban approved for post-arthroplasty prophylaxis. **Fondaparinux**: Alternative for heparin-induced thrombocytopenia (HIT).

### Condition-Specific Guidelines

**SCI**: LMWH for minimum **8-12 weeks**; some guidelines recommend until mobilization achieved. **Stroke**: LMWH or UFH within 24-48 hours (after hemorrhagic transformation is excluded). **TBI**: Pharmacologic prophylaxis delayed until hemorrhage stability confirmed (typically 24-72 hours); timing depends on neurosurgical assessment. **Hip/knee arthroplasty**: Extended prophylaxis for 28-35 days post-operatively.

| Population | DVT Risk Without Prophylaxis | Prophylaxis Agent | Duration | Timing Considerations |
|------------|-----------------------------|--------------------|----------|----------------------|
| SCI | 40-80% | LMWH | 8-12 weeks minimum | Begin once hemostasis assured |
| Stroke | 20-50% | LMWH or UFH | Duration of immobility | 24-48 hrs post-ischemic stroke |
| TBI | 20-30% | LMWH | Until mobilized | Delay 24-72 hrs for hemorrhage stability |
| Hip/knee arthroplasty | 40-60% | LMWH or DOAC | 28-35 days | Begin 6-12 hrs post-op |
| Hip fracture | 40-60% | LMWH | 28-35 days | Pre- or post-operative start |

### Mechanical Prophylaxis

**Intermittent pneumatic compression (IPC)** devices: First-line when pharmacologic prophylaxis is contraindicated. **Graduated compression stockings (GCS)**: Adjunct to pharmacologic prophylaxis. Early mobilization: The most fundamental mechanical prevention strategy. IPC should be applied consistently during periods of immobility.

### Inferior Vena Cava (IVC) Filters

Considered when anticoagulation is contraindicated AND high VTE risk exists. **Retrievable filters** preferred; should be removed when anticoagulation can be initiated. Not a substitute for anticoagulation; used as an adjunct or temporizing measure. Complications: Filter migration, IVC thrombosis, PE through filter.

## Diagnosis

### Clinical Presentation

**DVT**: Unilateral leg swelling, warmth, erythema, tenderness, calf pain. May be **asymptomatic** in 50% of cases, especially in paralyzed limbs. **PE**: Dyspnea, pleuritic chest pain, tachycardia, hypoxemia, hemoptysis. Massive PE: Hemodynamic instability, right heart failure, cardiac arrest.

### Diagnostic Workup

**D-dimer**: High sensitivity but low specificity; useful to rule out DVT in low-probability cases. Elevated D-dimer is common in rehabilitation patients (surgery, trauma, inflammation), limiting utility. **Compression ultrasonography**: Gold standard for DVT diagnosis; sensitivity >95% for proximal DVT. **CT pulmonary angiography (CTPA)**: Gold standard for PE diagnosis. **V/Q lung scan**: Alternative when CTPA is contraindicated (contrast allergy, renal insufficiency).

### Surveillance Versus Symptomatic Screening

Routine ultrasound surveillance is **not recommended** for most rehabilitation patients. Clinical vigilance with a low threshold for diagnostic testing is preferred. Weekly lower extremity circumference measurements may detect subclinical DVT in high-risk patients (SCI). ![Diagnostic algorithm for suspected DVT in rehabilitation patients](images/dvt-diagnostic-algorithm-rehab.png)

## Treatment

### Anticoagulation

**Initial treatment**: LMWH, UFH, or DOAC (rivaroxaban, apixaban as monotherapy). **Transition to long-term therapy**: Warfarin (INR 2-3) or DOAC. **Duration**: Minimum 3 months for provoked VTE; longer for unprovoked or recurrent VTE. SCI-related DVT: Typically 3-6 months; consider extended prophylaxis during ongoing immobility.

### Special Considerations in Rehabilitation

**TBI patients**: Anticoagulation may be contraindicated due to intracranial hemorrhage risk. Close monitoring for bleeding complications during active rehabilitation (falls risk). Physical therapy can continue during anticoagulation; modify high-fall-risk activities. Drug interactions: Warfarin with numerous medications; DOACs have fewer interactions. Rehabilitation should not be delayed for DVT treatment unless massive or symptomatic PE.

### Thrombolysis and Interventional Options

Systemic thrombolysis for massive PE with hemodynamic compromise. Catheter-directed thrombolysis for extensive iliofemoral DVT in select cases. Surgical thrombectomy for life-threatening PE when thrombolysis is contraindicated.

## Complications of VTE in Rehabilitation

### Post-Thrombotic Syndrome

Chronic venous insufficiency after DVT; affects **20-50%** of DVT patients. Symptoms: Leg pain, swelling, skin changes, venous ulceration. Compression therapy (30-40 mmHg) is the mainstay of management. Exercise and elevation complement compression. Impacts rehabilitation participation and quality of life.

### Chronic Thromboembolic Pulmonary Hypertension (CTEPH)

Occurs in 2-4% of PE survivors. Progressive dyspnea and exercise intolerance. Diagnosis: V/Q scan, right heart catheterization. Treatment: Pulmonary thromboendarterectomy; balloon pulmonary angioplasty.

## Key Clinical Pearls

1. Spinal cord injury carries the highest VTE risk of any rehabilitation population; pharmacologic prophylaxis with LMWH should be initiated within 72 hours of injury and continued for a minimum of 8-12 weeks. 2. DVT may be asymptomatic in up to 50% of cases in paralyzed limbs; clinical vigilance and a low threshold for compression ultrasonography are essential in high-risk rehabilitation patients. 3. In TBI patients, the timing of pharmacologic VTE prophylaxis must balance thrombotic risk against intracranial hemorrhage risk, typically initiated 24-72 hours after injury with neurosurgical clearance. 4. Active rehabilitation should continue during anticoagulation therapy for DVT; treatment of VTE is not a contraindication to physical therapy, though high-fall-risk activities should be modified.

![Timeline of VTE prophylaxis recommendations across rehabilitation diagnoses](images/vte-prophylaxis-timeline-rehab.png).

## References

1. Consortium for Spinal Cord Medicine. "Prevention of Venous Thromboembolism in Individuals with Spinal Cord Injury: Clinical Practice Guidelines." *J Spinal Cord Med*. 2016;39(3):232-247.
2. Dennis M, et al. "Effectiveness of Intermittent Pneumatic Compression in Reduction of Risk of Deep Vein Thrombosis in Patients Who Have Had a Stroke (CLOTS 3)." *Lancet*. 2013;382(9891):516-524.
3. Kearon C, et al. "Antithrombotic Therapy for VTE Disease: CHEST Guideline." *Chest*. 2016;149(2):315-352.
4. Piran S, et al. "Incidence and Risk Factors for Venous Thromboembolism in Traumatic Brain Injury: A Systematic Review." *Crit Care Med*. 2013;41(12):2767-2773.