1. DVT: Symptoms and work-up Sean Stoneking

2. DVT Epidemilogy Approximately 600,0000 new cases of DVT each year 50% in hospitalized patients or nursing home residents

3. Clinical Signs and Symptoms Up to 50% are asymptomatic Pain Edema Warmth Discoloration Palpable cord of a thrombosed vein Homan’s sign (present 1/3 of cases)

4. DDx of acute edema/leg pain? Infection Trauma/injury Venous insufficiency

5. Risk Factors: Virchow’s Triad Stasis Venous endothelial injury Hypercoagulable state

6. Risk factors Past DVT Immobilization Pregnancy OCP and HRT Trauma Obesity Age Sepsis Cancer Diseases that alter blood viscosity (sickle cell, polycythemia, multiple myeloma)

7. Risk Factors: Thrombophilias Anticoagulant protein deficiency (Protein C/S, Antithrombin Plasminogen, Heparin cofactor II) Dysfibrinogenemia Antiphospholipid antibodies Factor V Leiden mutation (heterozygous) Prothrombin G20210A mutation (heterozygous)

8. Wells pretest probability Clinical features 1. Active cancer (treatment within 6 months) 2. Paralysis, paresis, or immobilization of lower extremity 3. Bedridden for more than 3 days because of surgery (within 4 weeks) 4. Localized tenderness along distribution of deep veins 5. Entire leg swollen 6. Unilateral calf swelling of greater than 3 cm (below tibial tuberosity) 7. Unilateral pitting edema 8. Collateral superficial veins 9. Alternative diagnosis as likely as or more likely than DVT Points 1 -2

9. Pretest Probability Interpretation >=3 points: high risk (75%) 1 to 2 points: moderate risk (17%) <1 point: low risk (3%).

10. Ramzi and Leeper, Am Fam Phys 2004;69 (12).

11. Testing Modalities Ulrasonography D-dimers Contrast venography MRI Spiral CT

12. Ultrasound In the proximal veins sensitivity is 97% In the calf veins sensitivity is only 73% It cannot distinguish between an old clot and a new clot.

13. D-dimers Degradation product of a cross-linked fibrin blood clot. Levels also elevated in recent major surgery, hemorrhage, trauma, pregnancy or cancer. Sensitive but nonspecific The value is in a negative test result

14. Contrast venography “Gold Standard” for imaging DVT can image entire lower extremities Sensitive in asymptomatic patients Limitations: invasive, contrast reactions

15. MRI Good test for suspected iliac vein or inferior vena caval thrombosis More sensitive than any other noninvasive study in suspected calf vein thrombosis. Expense, lack of general availability

16. Spiral CT When PE is suspected, can scan chest and lower extremities with same amount of contrast. ~50% more costly than ultrasound Risk of contrast reaction

17. Summary Use risk stratification of H&P with diagnostic testing to make the diagnosis Up to 50% of pts with DVT are asymptomatic Negative D-dimer rules out DVT in low probability Ultrasound useful for diagnosing proximal thromboses MRI and contrast venography useful for diganosing distal thromboses

18. Location of DVT Scarvelis, D. et al. CMAJ 2006;175:1087-1092