Venous Thromboembolism Flashcards by Lauren F

What are the 3 parts of Virchow’s triad?

Vessel wall injury

Hypercoagulability

Stasis

How well did you know this?

Not at all

Perfectly

What are the “chronic” risk factors for VTE?

Malignancy

Antiphospholipid antibody syndrome

Myeloproliferative disorder

How well did you know this?

Not at all

Perfectly

What are the “transient states” that are risk factors for VTE

Surgery

Trauma

Immobilization

How well did you know this?

Not at all

Perfectly

What are the female specific risk factors for VTE

Pregnancy

Birth control

How well did you know this?

Not at all

Perfectly

What are the most common “inherited” risk factors for VTE

Factor V Leiden mutation

Prothrombin gene mutation

How well did you know this?

Not at all

Perfectly

What is the most useful finding when a patient presents with a DVT?

Larger calf diameter

How well did you know this?

Not at all

Perfectly

What does a palpable cord mean?

Thrombosed vein

How well did you know this?

Not at all

Perfectly

What are the 8 things in the DVT Wells score that are worth 1 point each?

Paralyisis/orthopedic casting
Bedridden/surgery
Tenderness
Swelling of entire leg
Calf swelling
Pitting edema
Cancer
Collateral non-varicose superficial veins

How well did you know this?

Not at all

Perfectly

What is worth -2 points on the wells score?

Alternative diagnosis more likely than DVT

How well did you know this?

Not at all

Perfectly

What wells score is considered a high probability for DVT?

How well did you know this?

Not at all

Perfectly

What is considered a positive D-Dimer?

Greater than 500ng/mL

How well did you know this?

Not at all

Perfectly

Is d-dimer sensitive? Is it specific?

It is sensitive but not specific.

Therefore it is only useful when it is negative and you have a low climnical suspicion of DVT

How well did you know this?

Not at all

Perfectly

What should your next step be if your patient has a high pretext probability for DVT?

Compression ultrasound

How well did you know this?

Not at all

Perfectly

What was considered the historical “gold standard” for diagnosing a DVT?

Contrast venography

We don’t do it as an initial screening anymore because it’s invasive and expensive

How well did you know this?

Not at all

Perfectly

What does a compression ultrasound look for?

Loss of vein compressibility, indicating a DVT

How well did you know this?

Not at all

Perfectly

How do you do a compression ultrasound?

Push down with the transducer and watch for the vein to collapse, if it doesnt collapse you know you have a clot

How well did you know this?

Not at all

Perfectly

What will Doppler ultrasound show you?

Blood flow

How well did you know this?

Not at all

Perfectly

Which is more likely to embolize: a proximal DVT or one below the knee?

Proximal. Absolutely must treat

How well did you know this?

Not at all

Perfectly

Are we trying to dissolve or remove the clot when we treat for DVT?

How well did you know this?

Not at all

Perfectly

What is the goal of DVT treatment?

Prevent further cot propagation

Prevent PE

Decrease risk of recurrent VTE

Decrease complications

How well did you know this?

Not at all

Perfectly

What is the mainstay of treatment for DVT?

Anticoagilaton

How well did you know this?

Not at all

Perfectly

When should you start anticoagulation therapy once you’ve decided to treat a DVT?

Immediately and up to the first 10 days

How well did you know this?

Not at all

Perfectly

What is the minimum amount of time someone should be on anticoagulant therapy?

3 months

Don’t EVER put someone on it and then take them off before 3 months

How well did you know this?

Not at all

Perfectly

What is post-thrombotic syndrome?

Chronic venous insufficiency due to fucked up valves after a DVT

How well did you know this?

Not at all

Perfectly

Should we use compression stockings to try to prevent post-thrombotic syndrome after a DVT?

Sure knock yourself out No clear evidence that they really work though

What usually causes DVT in the upper extremity?

Placement of catheter/central line/pacemaker

What usually causes superficial thrombophlebitis?

Peripheral IV

Would you see swelling of the limb with superficial thrombophlebitis?

No | DVTs always cause swelling

What are the 4 ways you can classify a PE?

1. Hemodynamics stability 2. Temporal pattern (acute, chronic) 3. Anatomic location 4. Symptomatic/asymptomatic

What does a “massive” PE mean

Hemodynamics instability

What are the criteria for a “massive” PE aka one with hemodynamics instability?

Systolic BP less than 90 Or BP drop of 40mm for at least 15 min

What is the most common presentation of PE

Shortness of breath followed by pleuritic pain Cough Symptoms from DVT

What should you do if you have a pt with a suspected PE and they are hemodyanmically stable?

Wells score D-dimer Diagnostic imaging

What is the imaging test of choice for a PE

CTPA

If you suspect your pt has a PE and they are hemodynamically unstable, what should you do?

Just do an echo right there at the bedside to look for collapse of the RV -which would indicate PE

What are the Wells criteria for PE?

Symptoms of DVT= 3 points Something other than a PE is unlikely= 3 points Heart rate over 100 = 1.5 points Immobilization = 1.5 points Previous DVT/PE = 1.5 points Hemoptysis = 1 point Malignancy = 1 point

What score on the Wells criteria for PE would mean a PE is likely?

4.5 or higher

What was the historical gold standard study for diagnosis of PE?

Pulmonary angiography (Not used much anymore due to new generation CTPA scanning that is less invasive, less expensive, and uses less contrast)

What kinds of PEs is CTPA a little less accurate at diagnosing?

Smaller, subsegmental PE | But who cares because they are irrelevant

What would make someone ineligible to have CT-Pulmonary angiography (CTPA)

IV contrast allergy Renal dysfunction

What would be an abnormal VQ scan?

Mismatch between ventilation and perfusion

Is VQ scanning sensitive? Is it specific?

It is sensitive, but not specific (many false positives)

Who are the best candidates for VQ scanning

Patients who have a normal chest radiograph. | They have good ventilation already, so the poor perfusion would be obvious

What are the classic findings on an EKG of someone with a PE?

S1Q3T3 pattern Right ventricular strain

Is chest x ray sensitive for PE? Is it specific?

Not sensitive. Not specific

What are the CXR findings you would see on someon with a PE?

Hampton’s hump Westermark sign

What are the 8 PERC criteria to rule out a PE

Under 50 yo HR under 100 95% pulse ox No hempoptysis No estrogen use No prior DVT/PE No leg swelling No surgery/hospitalization in last month

How many people who have PE will the PERC criteria miss?

1 in 50

When is the PERC rule best used?

In patients who present with chest pain or dyspnea, in whom the gestalt estimate for PE is less than 15%

How do you treat PE?

ANTICOAGULATION Supplemental O2 Intubate Vasopressors

Which factor Xa inhibitor is subcutaneous?

Fondaparinux (Arixtra)

Which factor Xa inhibitors are oral/

Rivaroxaban (Xarelto) Apixaban (Eliquis) Edoxaban (Savaysa)

What is the oral direct thrombin inhibitor?

Dabigatran (Pradaxa)

What kind of anticoagulant would you probably not use for someone with a PE who is stable?

IV unfractionated heparin

When would you use IV unfractionated heparin?

Massive iliofemoral DVT Hemodynamically unstable PE Severe renal failure Anyone who is more likely to require rapid reversal

What is the anticoagulant of choice for people who are pregnant or who have active cancer?

LMW heparin

What is the target INR range for someone on warfarin

2-3

Why do you have to give another anticoagulant when you start warfarin?

Because warfarin takes 5 days to kick in

What patients would you be nervous about giving anything but heparin and warfarin?

In patients who are bleeding risks and you wont be able to reverse the anticoagulant - prone to trauma - prone to falling (elderly/alcoholics) Etc

What is the reversal agent for unfractionated heparin?

Protamine

What is the reversal agent for LMW heparin?

Protamine (typically incomplete reversal)

What is the reversal agent for warfarin ?

Vitamin K Fresh frozen plasma

What is the reversal agent for Factor Xa inhibitors?

Andexanet alfa | $$$$$, hard to find

What is the reversal agent for the direct thrombin inhibitor (Dabigatran/pradaxa)?

Idarucuzumab $$$$$$$$

What is another agent that can be used to help stop bleeding in everyone?

Activated prothrombin complex concentrate (aPCC)

When should you test for inherited thrombotic disorders?

VTE before 45 yo AND a 1st degree relative with a VTE

What should you test for if you decide to test your pt for inherited thrombotic disorders

Antithrombin deficiency Protein S deficiciency Protein C deficiency Factor V Leiden Prothrombin gene mutation Antiphospholipid syndrome

When would you consider an IVC filter?

Anticoagulation is contraindicated Risk of bleeding outweighs risk of recurrent VTE Recurrent PE despite anticoagulation Hemodynamic/respirator compromise that is so severe, another PE might kill them

What is the problem with IVC filters?

After they’ve had it for awhile, clots start to build up around and on top of the filter, which can then embolize to the lungs It could also become dislodged and migrate

Is there any evidence that anticoagulation PLUS an IVC filter is better than anticoagulation alone?

Should your pt keep their IVC filter in forever?

No, remove it when no longer needed

When is the only time you would use a thrombolytic for a PE?

If the patient has a massive PE, is unstable, has hypotension, and cardiogenic shock AKA they’re gonna die

How do you prevent clots in an admitted hospital patient who has no risk factors for DVT/PE?

Mechanical prophylaxis only (Intermittent pneumatic compression or TED hose)

For admitted patients with one risk factor and no bleeding risk, how do we prevent clots?

Low dose SQ LMW heparin | No mechanical prophylaxis

For admitted patients with multiple risk factors for VTE, how do we prevent clots?

Mechanical and pharmacological prophylaxis BUT if they are a high bleeding risk, do mechanical only

Should we admit patients who have DVT or PE?

Yes almost everyone should be admitted to at least start the anticoagulant therapy