Anticoagulation in Thromboembolism

Aka: Anticoagulation in Thromboembolism, Pulmonary Embolism Anticoagulation, Deep Vein Thrombosis Anticoagulation, PE Anticoagulation, DVT Anticoagulation

1. See Also
   1. Deep Vein Thrombosis
   2. Pulmonary Embolism
2. Disposition
   1. Pulmonary Embolism
      1. Inpatient Anticoagulation
   2. Deep Vein Thrombosis
      1. Inpatient or outpatient management depending on risk
      2. See Deep Vein Thrombosis
3. Labs
   1. Initial labs
      1. Complete Blood Count
         1. Polycythemia, Thrombocytosis,associated with Splenomegaly (myeloproliferative disorder)
      2. ProTime (INR)
      3. Partial Thromboplastin Time (PTT)
         1. Increased PTT without correction by 1:1 dilution with normal plasma
            1. Seen with Lupus Anticoagulant syndrome
      4. Comprehensive metabolic panel (Liver Function Tests and Renal Function tests)
         1. Anticoagulant doses may require adjustment
      5. Urinalysis
         1. Proteinuria (e.g. Nephrotic Syndrome)
         2. Hematuria (e.g. cancer)
      6. Chest XRay
         1. Consider at time of initial diagnosis if chest CT was not done
         2. May indicate underlying malignancy
   2. Thrombophilia work-up in idiopathic or recurrent DVT
      1. See Thrombophilia
      2. Test only if results will direct therapy (especially duration of Anticoagulation)
      3. Reserve blood for tests prior to Anticoagulation
4. Preparations: Select form of Heparin
   1. Standard Heparin
      1. See Weight based Heparin nomogram for dosing
   2. Low Molecular Weight Heparin
      1. See Low Molecular Weight Heparin for dosing
      2. Efficacy
         1. Equivalent to standard Heparin in non-massive PE
            1. Quinlan (2004) Ann Intern Med 140:175-83
            2. Mismetti (2005) Chest 128: 2203-10
      3. Enoxaparin (Lovenox) 1 mg/kg twice daily or
      4. Enoxaparin (Lovenox) 1.5 mg/kg once daily or
         1. Single daily dosing not recommended for home use
      5. Tinzaparin (Innohep) 175 anti-Xa IU per kg daily
         1. Dose (ml): (weight in kg) x 0.00875 ml/kg daily
5. Management: Initiation
   1. Start Warfarin (Coumadin) concurrent with Heparin
   2. Contraindicated in pregnancy
      1. See DVT in Pregnancy
   3. Start Warfarin at 5 mg PO daily on Day 1-2
      1. See Warfarin for further dosing information
      2. Study: 10 mg start was therapeutic 1.4 days earlier
         1. Kovacs (2003) Ann Intern Med 138:714-9
   4. Check INR in 3-5 days
   5. Therapeutic INR: 2.0 to 3.0 IU
      1. Continue Heparin until INR is therapeutic
6. Management: Duration of Anticoagulation
   1. Anticoagulation duration has undergone significant changes over the last 5 years
      1. Prior 6-12 month Anticoagulation courses have dropped to 3 month recommendations in most cases
      2. Most difficult decision is determining who needs longterm therapy to prevent recurrence
         1. Those with transient causes (e.g. surgery, trauma) are at low risk
         2. Thorough history and exam is paramount in determining if Thrombophilia risk exists
            1. Focus on idiopathic cases
            2. Test only those where history and exam indicates
         3. D-Dimer protocol below may assist in risk stratifying idiopathic VTE and risk of recurrence
   2. Very low risk: 6-12 weeks
      1. Symptomatic isolated calf vein thrombosis
   3. Low risk patient: 3 months
      1. Reversible Venous Thromboembolism Risk (transient risk such as post-operative event) or
      2. Upper extremity Deep Vein Thrombosis
   4. Low to Moderate risk patient: At least 3 months
      1. First idiopathic distal DVT
      2. First idiopathic Pulmonary Embolism
   5. Moderate to high risk patient: Longterm therapy
      1. See Recurrent Thromboembolism Risks
      2. First idiopathic proximal DVT or PE
      3. Recurrent idiopathic DVT or PE
      4. Thrombophilia
   6. High risk patient: Low Molecular Weight Heparin (e.g. Lovenox)
      1. Active cancer (continue therapy while cancer active)
7. Management: Risk Stratification in Idiopathic first DVT
   1. D-Dimer after 3 months of Anticoagulation
      1. D-Dimer checked 4 weeks after stopping Anticoagulation
      2. Recurrent DVT is lower risk if D-Dimer is negative (3%/year contrasted with 9-10%/year if positive)
      3. (2006) NEJM 355:1780-9
      4. Verhovsek (2008) Ann Intern Med 149(7): 481-90
   2. Ultrasound affected extremity at 3 months of Anticoagulation
      1. Recurrent DVT is low risk if residual thrombus <40%
      2. However, other studies suggest that residual venous Occlusion is not a risk for recurrent VTE
      3. (2008) Blood 112:511-5
      4. Cosmi (2010) Eur J Vasc Endovasc Surg 39(3): 356-65
8. References
   1. Hyers (2001) Chest 119:176S-93S
   2. Galioto (2011) Am Fam Physician 83(3): 293-300