Iskander et al identified risk factors associated with extension of deep vein thrombosis from below the knee (infrageniculate) in a trauma patient. This can help identify patients who may benefit from more aggressive monitoring and anticoagulation. The authors are from the Marshfield Clinic in Wisconsin.


Patient selection: adult trauma patient with deep vein thrombosis in the calf veins (usually soleal vein plexus)


Factors affecting analysis:

(1) Patients were being treated with prophylactic doses of anticoagulants and/or mechanical prophylaxis whenever possible. Chemical prophylaxis was delayed until stable (3-7 days) if the patient had spinal cord injury, head injury or solid visceral injury. Mechanical prophylaxis consisted of a compression device in all patients whose injuries permitted their use.

(2) An infrageniculate deep vein thrombus that does not propagate is at low risk for significant pulmonary embolization.

(3) An infrageniculate deep vein thrombus that has not propagated tends to resolve quickly.


Parameters associated with a high risk of extension by multivariate analysis:

(1) age of the patient <= 62 years (odds ratio 18)

(2) severe traumatic injury with ISS > 35 (odds ratio 9)


These patients may benefit from therapeutic doses of anticoagulation therapy (higher doses than prophylactic).


Other factors influencing decision to be more aggressive in monitoring:

(1) ICU admission

(2) major surgery

(3) ISS > 20

(4) insertion of an inferior vena caval filter

(5) immobilization

(6) inability to provide adequate prophylaxis due to contraindications


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