Venous thromboembolism

People with spinal cord injury (SCI) are at significantly increased risk of developing venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE).

Risk factors

Venous thromboembolism risk is highest in the early weeks after injury but remains elevated for 3-6 months. Key risk factors include:

• New SCI, particularly within the first 2 weeks
• Motor complete injuries, i.e. ASIA Impairment Scale (AIS) A
• Lower limb or pelvic fractures
• Older age
• Previous venous thromboembolism
• Delayed or absent thromboprophylaxis (although VTE can occur even with appropriate pharmacological treatment)
• Dehydration

Clinical assessment

Early identification of VTE is critical. Monitor for the following signs and symptoms:

Pulmonary embolism (PE):

• Tachycardia or other arrhythmias
• Shortness of breath, especially with low oxygen saturations
• Chest pain, often worse with breathing
• Low-grade fever or unexplained raised temperature
• Anxiety
• Dizziness or syncope
• Acute confusion (may occur without chest pain)

Deep vein thrombosis (DVT):

• Unilateral swelling of a limb
• Calf tenderness
• Localised warmth or temperature change in the lower limbs

Thromboprophylaxis 

Thromboprophylaxis refers to the use of preventive measures to reduce the risk of blood clots (thromboses). The two main methods of thromboprophylaxis are:

1. Mechanical thromboprophylaxis 

• Graduated compression garments: These should be used from day 1 and must be fitted correctly to be effective.
• Intermittent pneumatic compression devices: More effective than the compression garments alone. Best used in combination with compression garments and pharmacological prophylaxis. 
• Mechanical prophylaxis may be contraindicated in patients with traumatic lower extremity injury. However, if no other contraindications, mechanical prophylaxis should be used in the uninjured leg.

In addition to mechanical prophylaxis, all people with an acute SCI should have pharmacological prophylaxis.  

2. Pharmacological thromboprophylaxis 

• After surgery reassess (and document) risks daily or more frequently if required.
• Add unfractionated heparin (UFH) when bleeding risk decreases and satisfactory haemostasis is achieved.
• Consider replacing with low molecular weight heparin (LMWH) after 3 days or as soon as bleeding risk decreases further.
• LMWH is preferred; low-dose UFH is an alternative.
• Duration: Continue for a minimum of 8 weeks after acute SCI, often up to 3 months. 

Considerations before starting or continuing pharmacological prophylaxis:

• Presence of intracranial pathology or neurosurgical injuries, undergoing procedures
• Body weight and body mass index (BMI) 
• Renal function
• Peri- or post-operative status
• Bleeding risk (e.g. bleeding disorders or a recent history of bleeding complications)

Inferior vena cava filters 

Inferior vena cava (IVC) filters are small devices placed in the body’s largest vein to prevent clots from reaching the lungs. There is currently no strong evidence to support prophylactic IVC filter placement in patients with contraindications to both pharmacological and mechanical prophylaxis, with benefits potentially outweighed by complications resulting from the filter.

Plan for prophylaxis interventions after acute spinal cord injury

If there are any concerns, contact QSCIS for advice.

• Call Princess Alexandra Hospital Switch: Ph (07) 3176 2111 and ask for the SIU Registrar (business days) or on-call Spinal Injuries Unit Consultant (during after-hours).