Venous Thromboembolism PDF

Venous Thromboembolism *Most thrombi form in deep veins of lower extremities. These lower extremity deep vein thrombi can embolize to the pulmonary arteries. Since the vast majority of pulmonary emboli are caused by DVTs, these disorders are often categorized together as thromboembolic disease or v...

Venous Thromboembolism *Most thrombi form in deep veins of lower extremities. These lower extremity deep vein thrombi can embolize to the pulmonary arteries. Since the vast majority of pulmonary emboli are caused by DVTs, these disorders are often categorized together as thromboembolic disease or venous thromboembolism (VTE). There are a series of inherited gene mutations that can place an individual at risk for VTE (and arterial thrombi).* [Primary Hypercoagulable States] Abnormal clotting in the vascular system due to a genetic predisposition for hypercoagulation and blood clot formation. Individuals with primary hypercoagulable states are at risk for: **Clinical Indicators** Presents with thromboembolic disease/events (e.g., DVT, PE, stroke, AMI) prior to age 45 Recurrent thrombotic events Family history of thromboembolic disease History of recurrent miscarriage, still birth, pregnancy complications Thrombi in unusual sites (e.g., mesenteric or cerebral veins) *Genetic Mutations that cause Hypercoagulability* **Factor V Leiden Mutation** This single gene mutation causes a change in factor V that removes the binding site for activated protein C *Note*: APC is a plasma protein that has anticoagulant and anti-inflammatory effects Prevalence Genetics: Autosomal dominant transmission Laboratory Evaluation: APC resistance assay and/or genetic testing for factor V Leiden mutation *Notes*: Cerebral vein thrombosis common; pregnant females have an increased risk of miscarriage and still birth; risk of arterial thrombosis causing stroke (in children as well as adults) and myocardial infarction (particularly in women) **Protein C Deficiency** Deficiency in activated protein C levels leads to increased risk of venous thromboembolism Genetics: Can be autosomal dominant (heterozygote or homozygote) or autosomal recessive transmission Prevalence: Protein C deficiency found in 2-5% of patients with thromboembolic disease Laboratory Evaluation: Quantitative assay for the protein C antigen (deficiency [\