VTE

Question 1

What is a VTE?

Answer 1

Clot formation within the venous circulation

Question 2

What are the two types of VTE?

Answer 2

DVT and PE

Question 3

What is a DVT?

Answer 3

A clot formed within a deep vein (usually in the legs)

Question 4

What is PE?

Answer 4

A clot in the pulmonary arteries

Question 5

What are the 3 primary factors influencing formation of a pathogenic clot? (Virchow’s triad)

Answer 5

1. Damage to vessel wall
2. Venous stasis
3. Hypercoagulable state

Question 6

What is the first step of blood clot formation?

Answer 6

Forming a platelet plug

Question 7

How do platelets adhere to the surface of the vessel?

Answer 7

The glycoprotein Ib receptor on the platelet surface binds to the von Willebrand ligand

Question 8

When platelets become activated, what do they release?

Answer 8

ADP, serotonin, and thromboxane A2

Question 9

What is the purpose of ADP, serotonin, and TXA2?

Answer 9

To recruit other platelets to the injured site and cause aggregation

Question 10

How does platelet aggregation occur?

Answer 10

glycoprotein IIb/IIIa on the platelet surface bind to fibrinogen

Question 11

What does antithrombin inhibit?

Answer 11

Factors IIa, IXa, and Xa

Question 12

What is the purpose of protein S?

Answer 12

It’s a cofactor in the activation of protein C

Question 13

What does protein C do?

Answer 13

It inactivates factors Va and VIIIa

Question 14

What does TFPI do?

Answer 14

Binds to factor VIIa-TF complex and inhibits activation of factor X

Question 15

What is plasminogen?

Answer 15

A precursor to plasmin activated by tissue plasminogen activator

Question 16

What does plasmin do?

Answer 16

It lyses fibrin to form fibrin degradation products

Question 17

What are the most common places for clot formation?

Answer 17

The muscular veins of the calf or the valve cusp pockets of the deep calf veins

Question 18

What can a DVT do once formed?

Answer 18

1. It can spontaneously lyse
2. Extend into more proximal veins
3. Embolize to lungs and cause PE

Question 19

What are the symptoms of a DVT?

Answer 19

1. unilateral calf swelling
2. calf pain/tenderness
3. erythema
4. warmth
5. palpable cord
6. positive Homan’s sign

Question 20

What are the symptoms of PE?

Answer 20

1. Dyspnea
2. Pleuritic chest pain
3. Anxiety
4. Tachypnea
5. Tachycardia
6. Cough
7. Hemoptysis
8. Diaphoresis

Question 21

What are the first steps of diagnosis?

Answer 21

1. Risk factor assessment

2. D-dimer

Question 22

What is a negative d-dimer test result?

Answer 22

less than 500 ng/ml or less than 0.5 mg/ml

Question 23

Once you confirmed the positive d-dimer, what test is next for DVT?

Answer 23

A non-invasive doppler ultrasonography and B-mode compression ultrasound or an invasive, and more expensive, contrast venography

Question 24

Once you confirmed the positive d-dimer, what test is next for PE?

Answer 24

A ventilation perfusion lung scan, chest CT scan, invasive pulmonary angiography, or ancillary test.

Question 25

What examples will cause damage to the vessel wall?

Answer 25

1. fractures/trauma
2. valvular disease or replacement
3. indwelling catheters
4. previous DVT/PE
5. malignancy
6. surgery (orthopedic)

Question 26

What examples will cause venous stasis?

Answer 26

1. immobility/bed rest/paralysis
2. pregnancy
3. increasing age (>40)
4. obesity