DVTs

Deep Vein Thromboses – Trey Richardson

  • Background: Incidence of 1-2 per 1,000 people per year
  • Depending on the study and population, associated with a 15% mortality rate
  • 70% of patients with PE have a detectable DVT
  • List of deep veins
    • Distal Lower Ext.: Posterior tibial, Anterior tibial, Peroneal, Gastrocnemius, Soleus veins
    • Proximal Lower Ext.: External, Internal, and Common iliac; Common, superficial, and deep femoral veins; Popliteal vein
    • Upper extremity: Radial, ulnar, brachial, axillary, and subclavian veins
  • Risk Factors for Provoked DVT/PE – Known Event
    • Major risk factors: major surgery >30 minutes, hospitalization > 3 days, C-section
    • Minor Risk Factors: Surgery <30 minutes, Hospitalization <3 days, pregnancy, estrogen therapy, reduced mobility >3 days, infection in past 3 months
  • Persistent risk factors: Malignancy (active), inflammatory bowel disease, hereditary thrombophilia, CHF
  • Active cancer (LR of 2.6) recent trauma/surgery or immobilization (LR of 1.6 each) are the clinical scenarios when suspicion should be the highest

 

Presentation

  • Asymmetric calf swelling of > 2cm sensitivity/specificity for DVT of 60-70% and a likelihood ratio (LR) of 2.1

 

Evaluation

  • Wells’ Criteria for DVT can help guide diagnostic testing
    • If a patient has a low pre-test probability, a negative D-dimer can rule out DVT
    • In a high pre-test probability patient a negative D-dimer is less helpful
  • Whole-leg (common femoral to deep calf veins) ultrasounds with doppler

 

Management

  • Prophylaxis
    • Padua score: Score > 4 high risk; A score <4 low risk for thrombosis
  • Choice of anticoagulation for treatment: (See anticoagulation section)
  • Duration of treatment
    • Provoked: 3-6 mos or until provoking factor (trauma, surgery, malignancy) is removed
      • Pts w/high risk cancers require more tailored therapy since the provoking factor is the malignancy itself. GI malignancies tend to be the highest risk.
    • Unprovoked: Requires life-long anticoagulation along with assistance from hematology
    • Recurrent: Even if they have all ben provoked, requires life-long treatment
      • Close follow-up with hematology
    • Distal:  Limited data, but can treat for 3 months or monitor for resolution with serial US
    • Upper Extremity: Treat as DVT for at least 3 months
    • Superficial vein : treat for 3 mo, if within 2 cm of junction w/ deep vein (high risk of propagation)

 

Additional Information

  • Decision to screen for hyper-coagulable disorders based on age (<45), history of prior DVTs, family hx of clotting disorders, and hx of thrombi in atypical locations (arterial) 
  • If no contraindications (acute bleeding, planned procedure, thrombocytopenia etc.) then most patients will tolerate prophylaxis
  • Follow up ultrasound
    • Limited data regarding utility of follow up ultrasound but may be warranted if patient at high risk for post-thrombotic complications or has persistent symptoms
  • What about IVC filters?
    • In patients at high risk for DVT and in whom anti-coagulation is contraindicated (thrombocytopenia, recent intra-cranial bleed, recent GI bleed) placement of a retrievable IVC filter should be discussed with IR