Exam 4 - Venous Thromboembolism Flashcards by Kelsey Peiser

What is the recurrence rate of venous thromboembolisms?

1/3 of persons who survive the first occurrence of VTE develop another VTE within 10 years

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What is Virchow’s Traid?

VTE Pathogenesis
Stasis (alterations in blood flow)
Hypercoagulability
Vascular endothelial injury

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What is considered a major risk factor for recurrent VTE?

Previous thrombotic event

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What are the most common chronic conditions that have an acquired risk factor for VTE?

Malignancy
Antiphospholipid antibody syndrome
Myeloproliferative disorders

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What are the most common transient states that have an acquired risk factor for VTE?

Surgery
Trauma
Immobilization
Presence of a central venous catheter

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What are the most common female specific factors that have an acquired risk factor for VTE?

Pregnancy

Hormonal contraceptives

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What are the most common inherited risk factors for VTE?

FactorV Leiden mutation

Prothrombin gene mutation

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What are the classic symptoms seen with DVT?

Often asymptomatic
Swelling
Pain
Warmth
Erythema
Palpable cord

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What is the most useful finding on exam for a DVT?

A large calf diameter

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What is Homan’s sign?

Positive if there is pain in the calf on abrupt dorsiflexion of the patient’s foot while the knee is extended
*Not commonly used (low sensitivity and specificity)

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What is the Wells criteria?

Scoring system to help confirm or rule out DVT before ordering any diagnostic tests

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What are some of the features included on the Wells criteria?

Paralysis or recent orthopedic casting
Bedridden
Major surgery
Localized tenderness
Swelling of entire leg
Calf swelling
Pitting edema
Active cancer

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What feature on the Wells criteria has a score of -2?

Alternative diagnosis more likely than DVT

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What does a Wells score of >3 indicate?

High probability of DVT

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What does a Wells score of 1-3 indicate?

Moderate probability of DVT

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What does a Wells score of 0 or less indicate?

Low probability of DVT

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After calculating the pretest probability, what should be done for patients with low or moderate probability for DVT?

D-dimer should be ordered

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What what levels in a serum D-dimer detectable?

Greater than 500 ng/mL in virtually all patients with VTE

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Does the D-dimer test have high sensitivity or specificity? What does that mean?

The test is sensitive, but not specific

Only useful when negative and low clinical suspicion

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If a patient has a low or moderate pretest probability for DVT and a negative D-dimer what should be done?

Nothing, no further work up needed

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After calculating the pretest probability, what should be done for patients with high probability for DVT?

D-dimer is inappropriate, further workup required
Compression ultrasound
(CTV and MRV rarely used)

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What is the indicated treatment DVTs?

Anticoagulants

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What is the purpose of anticoagulants in the treatment of DVT?

Prevent further clot propagation
Prevent pulmonary embolism
Decrease risk of reoccurrence
Decrease risk of complications

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What is not the purpose of treatment of DVT through anticoagulation?

To dissolve the clot

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How long is initial anticoagulation given for DVT?

10 days

How long is long term anticoagulation given for DVT?

Minimum of 3 months

Along with anticoagulants, what else is used in the treatment of DVT?

Early ambulation | Compression stockings

What can cause upper extremity DVT?

Spontaneous | Secondary- more common (catheter placement)

What is the most common cause of a pulmonary embolism?

Proximal DVT

What are the four ways in which a pulmonary embolism can be classified?

1. Hemolytic stability 2. Temporal pattern 3. Anatomic location 4. Presence or absence of symptoms

What defines hemodynamic instability in PE?

Systolic BP less than 90 or a drop in systolic blood pressure of more than 40 from baseline for more than 15 min

What is the prognosis for hemodynamic instability in PE?

These patients are likely to die from obstructive shock in the first 2 hrs of presentation

What are some signs and symptoms associated with PE?

``` Dyspnea Pleuritic pain Swelling or pain Cough Tachypnea Tachycardia ```

If you are clinically suspicious of a PE and your patient is hemodynamically stable, what should you do?

Wells criteria D-dimer Definitive CT pulmonary angiogram (CTPA) imaging

If you are clinically suspicious of a PE and your patient is hemodynamically unstable, should you get imaging?

No | Imaging is unsafe, besides echocardiography

If based on the Wells criteria, your patient has a low clinical probability of PE, what should you do next?

PERC

If your patient fulfills all 8 of the PERC criteria (PERC negative), what should you do?

Nothing, no additional testing required

If your patient does not fulfill PERC criteria, what should you do next?

D-dimer

If your patient's D-dimer test is negative, what should you do next?

Nothing, no additional testing required

If your patient's D-dimer test is positive, what should you do next?

More imaging is required

``` Age <50 yrs HR <100bpm O2 saturation >95% No hemoptysis No estrogen use No prior DVT or PE No unilateral leg swelling No surgery/trauma requiring hospitalization within the prior four weeks ``` What is the name of this criteria list? What is it used for?

PERC Rule | Alternative to further testing in patient with low probability assessment for PE

If based on the Wells criteria, your patient has an intermediate clinical probability of PE, what should you do next?

D-dimer D-dimer + = proceed to diagnostic imagaing D-dimer - = no further work up needed

If based on the Wells criteria, your patient has a high clinical probability of PE, what should you do next?

D-dimer NOT indicated | Go straight to diagnostic imaging

What is a low clinical probability score for PE on the Wells criteria?

Less than 2

What is an intermediate clinical probability score for PE on the Wells criteria?

Between 2-6

What is a high clinical probability score for PE on the Wells criteria?

Greater than 6

What is the diagnostic test of choice for PE?

CTPA (CT pulmonary angiogram)

Why would you not be able to obtain a CTPA? What could you do instead?

``` IV contrast allergy or renal dysfunction Ventilation perfusion (V/Q) ```

Why is CTPA not used as a test of choice for PE?

Sensitive, but poorly specific (high number of false positives) Intermediate results lead to a diagnostic delemma

What is the treatment for PE?

``` Anticoagulants Supportive care such as: Supplemental O2 Mechanical ventilation Vasopressors ```

For patients with a low risk of bleeding and a high clinical suspicion for PE, what should you consider?

Empiric anticoagulation

What anticoagulant is given parentally?

Unfractionated Heparin (UFH)

What anticoagulation do most patients use?

Low molecular weight heparin (LMWH) Warfarin Factor Xa Inhibitors (fondaparinux or apixaban)

In patients with severe renal failure, hemodynamic instability or massive illiofemoral DVT and those more likely to require rapid reversal of anticoagulation, which anticoagulant is preferred?

IV UFH

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

Low molecular weight heparin (LMWH)

What should you consider when transitioning a patient from initial to long-term anticoagulant treatment?

Treatment should not be interrupted, ensure therapeutic levels are maintained

What anticoagulant is commonly used for long term therapy? How is it monitored?

Warfarin PT (prothrombin time) INR (international normalized ratio)

Why is an additional anticoagulant often provided when beginning warfarin?

Warfarin has a slow onset

What is an option for patients who wish to avoid the burden of INA monitoring that comes along with warfarin?

Factor Xa inhibitors

What is the anticoagulant reversal agent for UFH?

Protamine

What is the anticoagulant reversal agent for LMWH?

Protamine

What is the anticoagulant reversal agent for warfairin?

Vitamin K and fresh frozen plasma

What is the anticoagulant reversal agent for Factor Xa inhibitors?

Tranexamic acid

What is the anticoagulant reversal agent for direct thrombin inhibitor?

Idarucizumab

Who might benefit from indefinite anticoagulation therapy?

Those with a first or recurrent episode of unprovoked proximal DVT/unprovoked symptomatic PE

What can be given in conjunction with an anticoagulant for unstable patients with PE?

Thrombolytics "clot buster"

What can be used as an alternative or adjunct therapy to anticoagulants in patients for which anticoagulation is contraindicated, risk of bleeding outweighs the risk of thromboembolism or if they are hemodynamically unstable?

IVC filter

What does an IVC prevent?

Propagation to lungs

Why wouldn't every patient with a DVT get an IVC?

Invasive No evidence that anticoagulation + iVF filter is better than anticoagulation alone Clots can build up around the filter over time

What can be done prophylactically for VTE?

Intermittent pneumatic compression Thromboembolic deterrent Graduated compression stocking Early ambulation