Acute Thrombosis

This 50 year old man has suffered a recurrent venous thrombosis, most likely from suboptimal prophylactic anticoagulation. The target INR for warfarin anticoagulation to prevent recurrent thromboembolism is 2.0-3.0. When a new thrombosis is diagnosed, therapeutic doses of heparin must be initiated. Simply increasing the warfarin dose to bring the INR into therapeutic range is inadequate, because warfarin is used for prophylaxis only, rather than for the treatment of acute thrombosis. For the same reason, switching to a different anticoagulant like dicumarol would be ineffective. After starting up heparin he should be restarted at a higher dose of warfarin.

Interruption of the inferior vena cava with a filter is primarily indicated only for patients in whom anticoagulation is contraindicated or in whom thrombosis has recurred despite adequate prophylactic anticoagulation. Neither of these considerations applies to this patient.

Thrombolytic therapy is not necessary in most case of DVT of the leg. This mode of therapy can be considered in patients with extensive venous thrombosis, particularly involving extension into the inferior vena cava, in order to prevent long-term postphlebetic complications.

Of note, Low Molecular Weight Heparins (LMWH) will be of major therapoutic thrust soon. Recent studies have shown the LMWH to be of possible benefit in the treatment of D.V.T.'s (4,5,7,8 ) and in documented pulmonary embolism (6).

References:

  1. Nichols WL, et al. Mayo Clinic Proc 1993: 68:897-8.
  2. Magnant JG, et al. J Vasc Surg 1992; 16: 701-6.
  3. Baker WF, et al. Med Clin North Am. 1994; 78:685-712.
  4. Weitz JI. Low-molecular-weight heparins. N Engl J Med 337 (10):688 - Review Article.
  5. The Columbus Investigators. Low-molecular-weight heparin in the treatment of patients with venous thromboembolism. N Engl J Med 337 (10):657
  6. Simonneau G, Sors H, Charbonnier B, Page Y, Laaban JP, Azarian R, Laurent M, Hirsch JL, Ferrari E, Bosson JL, Mottier D, Beau B. A comparison of low-molecular-weight heparin with unfractionated heparin for acute pulmonary embolism. N Engl J Med 337 (10):663.
  7. Koopman MMW, Prandoni P, Piovella F, et al. Treatment of venous thrombosis with intravenous unfractionated heparin administered in the hospital as compared with subcutaneous low-molecular-weight heparin administered at home. N Engl J Med 334 (11):682
  8. Levine M, Gent M, Hirsh J, et al. Comparison of low-molecular-weight heparin administered primarily at home with unfractionated heparin administered in the hospital for proximal deep-vein thrombosis. N Engl J Med 334 (11):677.

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