Venous Thromboembolism Flashcards
What is the most common preventable cause of hospital related death?
Venous Thromboembolism
Medicare has classified VTE as a never event after which operations?
total hip or knee replacement
Which chronic conditions are acquired risk factors for VTE?
chronic diseases of course, malignancy, obesity, antiphospholipid antibody syndrome, advanced age, smoking, myeloproliferative disorders
Which transient states are acquired risk factors for VTE?
surgery, trauma, immobilization, infection, hospitalization, long haul air travel
Which female specific factors are acquired risk factors for venous thromboembolism?
pregnancy, post-partum, hormonal contraceptives and hormone replacement therapy
What are the inherited risk factors for venous thromboembolism?
factor V Leiden mutation, Prothrombin gene mutation, protein S deficiency, protein C deficiency, antithrombin deficiency, dysfibrinogenemia (rare)
What are DDx for DVT?
musculoskeletal injury, leg swelling in paralyzed leg, lymphangitis or lymph obstruction, venous insufficiency, popliteal (baker’s) cyst, cellulitis, knee abnormality
Clinical presentation of DVT
often asymptomatic, swelling, pain, warmth, redness or discoloration
What should be obtained for a history in cases of suspected DVT?
obtain a good history for risk factors, get an Ob/GYN history in women, think about iccult malignancy, elicit a good family history
What should be included in physical exam for DVT?
vascular, extremities (including Homan’s sign with its questionable reliability), chest, cardiac, abdominal, skin
Which clinical features earn a score of 1 on the Wells score?
- active cancer
- paralysis, paresis or recent plaster immobilization of the lower extremities
- recently bedridden for more than 3 days or major surgery w/in 4 weeks
- localized tenderness along the distribution of the deep venous system
- entire leg swollen
- calf swelling by more than 3 cm when compared to the asymptomatic leg
- pitting edema (greater in the symptomatic leg)
- collateral superficial veins (nonvaricose)
- alternative diagnosis as likely or more likely than that of deep venous thrombosis
What can a Wells score tell you?
pretest probibility of deep vein thrombosis
What do the scores mean? and the modified score?
3 or greater: high probability of DVT
1 or 2: moderate probability of DVT
0 or less: low probability of DVT
Modification also takes previously dovumented DVT into account: 2 or greater: DVT likely, 1 or less DVT unlikely
What labs might be used to determine DVT?
CBC (with platelets), coagulation studies (PT/INR, aPTT), metabolic panels (renal, liver), urinalysis, D-dimer
What is the D-dimer test about?
In the presence of DVT and PE, endogenous fibrinolysis causes release of D-dimers from fibrin clot
What is the sensitivity and specificity of the D-dimer test? Why do we use the D-dimer test?
High sensitivity (97%), low specificity (45%) should be used as a "rule out" test
What are 4 causes of elevated D-dimer that the slides/instructor indicate that we should know?
venous thromboembolic disease, post-operative state, malignancy, normal pregnancy
What is the “test of CHOICE” to dx DVT?
compression ultrasonography will show loss of vein compressibility, doppler technique assesses blood flow
What is the “GOLD STANDARD” in DVT dx?
contrast venography, although this is rarely used
note: study the algorithm on slide 21, maybe make some flash cards in the future when less tired
slide 21 of the VTE lecture
What is the purpose of treating DVT?
to prevent clot propagation, PREVENT PE, decrease risk of recurrent VTE, decrease complications (such as post-thrombophlebitic syndrome and chronic venous insufficiency which cause significant morbidity over patient life)
How common is upper extremity DVT?
it is rarer than lower extremity DVT
1-4% of all upper extremity DVTs are _______
spontaneous
What can spontaneous DVTs can be associated with?
thoracic outlet syndrome
Name 2 causes of secondary upper extremity DVT
cathater placement, prothrombotic states
In what percentage of upper extremity DVTs do pulmonary embolisms occur?
4-10%