Thromboembolism Risk Factors

1. See Also
   1. Deep Vein Thrombosis (DVT)
   2. Pulmonary Embolism (PE)
   3. Thrombophilia
2. General
   1. Patients without risk Factors under age 40 years: 28%
3. Risk Factors: Initial Venous Thromboembolism
   1. Major transient risks
      1. Hospitalization
      2. Plaster cast immobilization
      3. Surgery
      4. Trauma
   2. Minor transient risks
      1. Prolonged travel >2 hours (risk increases 18% for every 2 hours traveled)
      2. Pregnancy
      3. Oral Contraceptives or other hormone therapy
   3. Persistent risks
      1. Collagen vascular disease
      2. Heart Failure
      3. Cancer
      4. Myeloproliferative disorders
      5. Nephrotic Syndrome
      6. Recurrent Pregnancy Loss
4. Risk Factors: Recurrent Thromboembolism after stopping anticoagulants (relative risk)
   1. Metastatic cancer (6-9)
   2. Factor VIII >200 IU/dl (6)
   3. Non-metastatic Cancer (3)
   4. Antiphospholipid Antibody Syndrome (2.5)
   5. D-Dimer increase after acute therapy completed (2.2)
   6. Persistent risk factors - see above (2)
   7. Idiopathic VTE (2)
   8. Protein C,Protein S and antithrombin deficiency (1.8)
   9. Prothrombin mutation - G20210A (1.7)
   10. Homozygous for Factor V Leiden (1.6)
   11. Second VTE (1.5)
   12. Mild Hyperhomocysteinemia (0.9)
   13. Distal VTE (0.5)
   14. Transient risk factors (0.5)
   15. Kearon (2008) Chest 133(6 suppl):454S
5. Risk Factors: Venous Stasis
   1. Prolonged immobility
   2. Long leg Fracture or other limb immobilization
   3. Paralysis
      1. Cerebrovascular Accident (CVA)
      2. Spinal cord injury
   4. Varicose Veins
      1. High risk for DVT in surgery without DVT Prophylaxis
   5. Obesity
   6. Cardiac Disease
      1. Congestive Heart Failure
      2. Atrial Fibrillation
      3. Myocardial Infarction
6. Risk Factors: Hypercoagulable
   1. Hypercoagulable state
      1. See Thrombophilia
      2. Inherited cause found in up to one third of DVT cases
         1. Mateo (1997) Thromb Haemost 77:444-51
   2. Prior Deep Vein Thrombosis (DVT)
   3. Medications
      1. Increased Estrogen
         1. Oral Contraceptive or Estrogen Replacement
         2. Pregnancy
         3. Tamoxifen (Nolvadex)
      2. Hydralazine
      3. Phenothiazines
      4. Procainamide
   4. Major trauma
   5. Recent Surgery
   6. Autoimmunity (e.g. Systemic Lupus Erythematosus)
   7. Cancer
      1. Colon Cancer
      2. Ovarian Cancer
      3. Multiple Myeloma
      4. Consider evaluation for occult cancer in DVT
   8. Chemotherapy
   9. Inflammatory Bowel Disease
   10. Polycythemia
   11. Sickle Cell Anemia
   12. Nephrotic Syndrome
   13. History of thromboembolic disease
       1. Deep Venous Thrombosis
       2. Pulmonary Embolus
   14. Type A Blood
7. Risk Factors: Intimal damage
   1. Local trauma
   2. Surgery (Especially General and Orthopedic Surgery)
      1. General anesthesia is an independent risk factor
      2. Consider DVT Prophylaxis
   3. Penetrating vessel injury
      1. Intravenous Drug Abuse
      2. Central line placement
         1. Especially femoral central line
8. References
   1. Heit (2002) Arch Intern Med 162:1245-8