Management of suspected deep venous thrombosis - Tips from Other Journals

Date: May, 1992

The appropriate management of lowerextremity deep venous thrombosis is a difficult problem for the practicing physician. The decision to use anticoagulation therapy to prevent possibly fatal pulmonary embolism is not without expense and risk of morbidity. The diagnosis of deep venous thrombosis is imprecise, necessitating objective studies before initiation of anticoagulation therapy. Venography has been the gold standard for diagnosis, but less invasive tests have recently been used to manage suspected deep venous thrombosis. Hillner and colleagues used decision analysis to model the consequences of 24 different strategies for the management of suspected lower-extremity deep venous thrombosis.

Decision analysis was used on existing data concerning the diagnosis of deep venous thrombosis. To generate a decision tree, certain assumptions were made regarding deep venous thrombosis and pulmonary embolism. These assumptions included the following: (1) The risk of pulmonary embolism decreased as soon as anticoagulation therapy was initiated. (2) No patient could have more than one event in the three months modeled. (3) Complications of diagnosis and treatment were limited to anaphylactic dye reaction, pulmonary embolism and hemorrhagic complications. (4) No test result was indeterminate or nondiagnostic. (5) Patient age was not a factor. (6) There were no contraindications to either anticoagulation therapy or intravenous contrast dye.

The authors designed different strategies and then analyzed them based on cost per patient and the number of deaths per 1,000 patients. Tests used were venography, impedance plethysmography and real-time ultrasonography. Therapy included seven days of intravenous heparin and three months of warfarin.

The authors found by their analysis that the optimal strategy if a lower-extremity deep venous thrombosis was found was real-time ultrasonography followed by anticoagulant therapy. They found that this method was both effective and cost-saving, compared with no testing or treatment. Follow-up studies of patients with initially negative studies saved additional lives, but at a cost of $390,000 per each life saved with one follow-up study and $3.5 million for each life saved when a second follow-up study was performed.

The authors conclude that venography should play a limited role in the assessment of deep venous thrombosis. Venography is indicated in high-risk patients in whom the probability of thrombosis in the thigh is suspected to exceed 50 percent and whose initial noninvasive study suggests no deep venous thrombosis. They believe that more information is needed regarding identification of a subset of patients who would benefit from serial testing. At this time, the cost of serial testing is extremely high for the number of lives potentially saved. (Archives of Internal Medicine, January 1992, vol. 152, p. 165. )

COPYRIGHT 1992 American Academy of Family PhysiciansCOPYRIGHT 2004 Gale Group

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