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Risk Factors for Venous Thromboembolism (VTE)
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Evaluation of a Patient After a VTE: Routine Evaluation
History and examination to identify acquired risk factors (see above). This should include obstetric history in women because recurrent second- or third-trimester fetal loss may suggest antiphospholipid antibody syndrome or hereditary thrombophilia
Detailed family history with inquiry regarding female family members who have taken oral contraceptives or suffered any venous thrombotic events during pregnancy
CBC and peripheral smear to evaluate for underlying disease (eg, myeloproliferative disorder such as essential thrombocythemia, polycythemia vera or microangiopathic hemolysis)
Other laboratory tests as indicated (eg, antibody testing to evaluate for heparin-induced thrombocytopenia if applicable)
Extensive screening for malignancy not recommended. Perform age-appropriate screening as indicated. Lower threshold to search for malignancy based on symptoms or signs, especially in older patients with a smoking history, recurrent or bilateral VTE
Thrombophilia screen as outlined below for idiopathic deep vein thrombosis
Who should be tested for hereditary thrombophilia?
Yes
VTE at age <50 years with positive family history (first-degree relatives)
Cerebral venous thrombosis
Portal/mesenteric vein thrombosis (rule out myeloproliferative neoplasms such as polycythemia vera, essential thrombocythemia, and paroxysmal nocturnal hemoglobinuria)
Pregnancy loss (second and third trimester)
Reasonable
No
Arterial thrombosis (except for paradoxical emboli)
Asymptomatic patients with no personal or familial history of VTE
Women using oral contraceptives with no familial history of VTE
Venous thromboembolism in patients with active cancer
Elderly patients with postoperative venous thromboembolism
Retinal vein thrombosis
Laboratory Evaluation for Recurrent Arterial Thrombosis
Only the presence of a lupus anticoagulant/elevated cardiolipin antibody levels are risk factors for arterial thrombosis; the hereditary thrombophilias are not risk factors
Consider other disease states, including paroxysmal nocturnal hemoglobinuria, heparin-induced thrombocytopenia, occult malignancy, myeloproliferative disorders, and cocaine abuse
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Acquired Risk Factors
1. Malignancy-Associated Thrombosis
General:
Accounts for approximately 20% of all cases of VTE
In some prospective studies, the incidence of malignancy in the first year after diagnosis of an idiopathic VTE is >7%. However, trials have not demonstrated improved patient outcomes and cost-effectiveness of extensive screening beyond age-appropriate or symptom-directed cancer screening
Pathogenesis:
Etiology not clearly established
May be related to tissue factor elaborated by tumor cells
Management of thrombosis:
Acute thrombosis: Heparin or low-molecular-weight heparin (LMWH)
Long-term therapy: Patients with cancer have a higher risk of recurrence than individuals who suffer an unprovoked VTE in the absence of cancer. Anticoagulate a minimum of 6 months and as long as ...