What are the RFs for VTE?
Age H/o VTE Venous stasis Venous injury Hypercoaguable disorders Drug therapy
What are the pieces of Virchow’s triad?
Venous stasis
Vascular injury
Hypercoagulability
What are the types of venous stasis?
Immobility
Paralysis
A fib
LV dysfunction
What are the types of vascular injury?
Indwelling catheter
Trauma
Surgery
What are the types of hypercoagulability?
Protein C and S deficiencies
Antithrombin deficiency
Malignancy
What are the types of hypercoagulable hereditary disorders?
Activated protein C resistance/Favtor V Leiden mutation Prothrombin gene mutation Protein C deficiency Protein S deficiency Antithrombin deficiency
In patients with Factor V Leiden mutation, what happens to clot formation?
Continues unchecked
What is protein C?
Endogenous anticoagulant responsible for degrading factor V and preventing further activation of the coagulation cascade
What does the prothrombin gene mutation cause?
Increased levels of prothrombin (needed in clot formation)
What is protein S?
One of the cofactors responsible for activation of protein C
What is antithrombin responsible for?
Inactivation of factors X and II
What are acquired hypercoagulable disorders?
Pregnancy
Antiphospholipid antibodies
Drug therapy
Malignancy
How does pregnancy cause hypercoagulable disorders?
D/t increased levels of estrogen during pregnancy and the immediate postpartum period
Where are antiphospholipid antibodies commonly found?
Patients with autoimmune disorders such as lupus or inflammatory bowel disease
What do antibodies do in the coagulation cascade?
Activate the coagulation cascade and platelets while inhibiting the activity or proteins C and S
What are s/sx of SVT?
Unilateral calf, leg or thigh swelling Leg pain/calf tenderness Increased leg warmth Edema Erythema Palpable thrombosed vein Homan's sign
What are the s/sx of PE?
Dyspnea Tachypnea Tachycardia Hemoptysis Chest pain and/or tightness Cough
What is the diagnosis of DVT/PE?
D-dimer
What is the D-dimer normal range?
0-250
Does the D-dimer have a low or high positive predictive value and specificity?
Low
What are non-invasive DVT-specific diagnostic testing?
Duplex ultrasonography
What is duplex ultrasonography?
Can measure the rate and direction of blood flow and visualize clot formation in proximal veins of the legs
What is preferred to venography?
Duplex ultrasonography
What are he invasive diagnostic tests for DVT?
Contrast venography