Ch 300: Deep Venous Thrombosis and Pulmonary Thromboembolism

Question 1

The two most common autosomal dominant genetic mutations are ______ _ ______, which causes resistance to the endogenous anticoagulant, activated protein C (which inactivates clotting factors V and VIII), and the ___________ ____ ________, which increases the plasma prothrombin concentration.

Answer 1

factor V Leiden

prothrombin gene mutation

Question 2

What is the most common acquired cause of thrombophilia?

Answer 2

Antiphospholipid antibody syndrome

Question 3

Virchow’s triad consist of…

Answer 3

…inflammation, hypercoagulability, and endothelial injury.

Question 4

What 3 substances are naturally occurring coagulation inhibitors?

Answer 4

Antithrombin, protein C, and protein S

Question 5

Paradoxically, these thrombi in the heart occasionally embolize to the arterial circulation through a…

Answer 5

…patent foramen ovale or atrial septal defect.

Question 6

In the patient with a PE, physiologic dead space increases because…

Answer 6

…ventilation to gas exchange units exceeds venous blood flow through the pulmonary capillaries.

Question 7

Leg DVT is about __ times more common than upper extremity DVT,

Answer 7

10

Question 8

Low-risk PE constitutes about what % of cases?

Answer 8

70 - 75%

Question 9

Lower extremity DVT usually begins…

and propagates…

Answer 9

…in the calf

…proximally to the popliteal vein, femoral vein, and iliac veins.

Question 10

Superficial venous thrombosis usually presents with…

Answer 10

…erythema, tenderness, and a “palpable cord.”

Question 11

Patients with a low-to-moderate likelihood of DVT or PE should undergo initial diagnostic evaluation with…

Answer 11

…d-dimer testing alone without obligatory imaging tests.

Question 12

However, for patients with a high clinical likelihood of VTE…

Answer 12

…skip d-dimer testing and undergo imaging as the next step in the diagnostic algorithm.

Question 13

Not all leg pain is due to DVT. Sudden, severe calf discomfort suggests a…

Answer 13

…ruptured Baker’s cyst.

Question 14

Pulmonary infarction usually indicates a small PE. This condition is exquisitely painful because…

Answer 14

…the thrombus lodges peripherally, near the innervation of pleural nerves.

Question 15

What rare type of embolisms can occur after total hip or knee replacement?

Answer 15

Cement embolism and bony fragment embolism

Question 16

Which clotting factors does activated protein C inactivate?

Answer 16

Factors V and VIII

Question 17

RV wall tension also compresses the right coronary artery, limits myocardial oxygen supply, and precipitates…

Answer 17

…right coronary artery ischemia and RV microinfarction, with release of cardiac biomarkers such as troponin.

Question 18

The quantitative plasma d-dimer enzyme-linked immunosorbent assay (ELISA) rises in the presence of DVT or PE because…

Answer 18

…of the breakdown of fibrin by plasmin.

Question 19

D-dimer rarely has a useful role among hospitalized patients, because levels are…

Answer 19

…frequently elevated due to systemic illness.

Question 20

The most frequently cited abnormality, in addition to sinus tachycardia, is the S1Q3T3 sign: __ _ ____ in lead _, _ _ ____ in lead ___, and __ ________ _ ____ in lead ___. This finding is relatively specific but insensitive. RV strain and ischemia cause the most common abnormality, ______ _________ in leads __ to __.

Answer 20

an S wave in lead I
a Q wave in lead III
an inverted T wave in lead III
T-wave inversion in lead V1 to V4

Question 21

What is Westermark’s sign?

Answer 21

focal oligemia – radiographic sign of PE

Question 22

What is Hampton’s hump?

Answer 22

a peripheral wedged-shaped density above the diaphragm – radiographic sign of PE

Question 23

What is Palla’s sign?

Answer 23

an enlarged right descending pulmonary artery – radiographic sign of PE

Question 24

RV enlargement on chest CT indicates an increased likelihood of death within the next…

Answer 24

…30 days compared with PE patients who have normal RV size.

Question 25

A high-probability scan for PE is defined as…

Answer 25

…two or more segmental perfusion defects in the presence of normal ventilation.

Question 26

_____ ____ ________ of patients with angiographically confirmed PE have a high probability V/Q scan.

Answer 26

Fewer than one-half

Question 27

The best-known indirect sign of PE on transthoracic echocardiography is __________ sign: hypokinesis of the RV free wall with….

Answer 27

McConnell’s

normal or hyperkinetic motion of the RV apex.

Question 28

Anticoagulation or placement of an inferior vena caval filter constitutes _________ prevention of VTE.

Answer 28

secondary

Question 29

When RV function remains normal in a hemodynamically stable patient with PE, a good clinical outcome is highly likely with…

Answer 29

….anticoagulation alone.

Question 30

What is one benefit of fondaparinux?

Answer 30

It does not cause heparin-induced thrombocytopenia.

Question 31

Warfarin is a vitamin K antagonist that prevents carboxylation activation of what coagulation factors?

Answer 31

II, VII, IX, and X

Question 32

___________, a factor Xa inhibitor, is approved for treatment of acute DVT and acute PE as monotherapy, without a parenteral “bridging” anticoagulant.

Answer 32

Rivaroxaban

Question 33

There is no specific ________ _____ for bleeding caused by fondaparinux, direct thrombin inhibitors, or factor Xa inhibitors.

Answer 33

reversal agent

Question 34

Major bleeding from warfarin is best managed with ___________ _______ ___________. With serious but non–life-threatening bleeding, _____-______ ______ or ___________ _______ _ can be used.

Answer 34

prothrombin complex concentrate

fresh-frozen plasma or intravenous vitamin K

Question 35

What is the minimum duration of anticoagulation for patients with one episode of DVT?

Answer 35

3 months

Question 36

The two principal indications for insertion of an IVC filter are:

Answer 36

(1) active bleeding that precludes anticoagulation

(2) recurrent venous thrombosis despite intensive anticoagulation

Question 37

For patients with massive PE and hypotension, replete volume with ___ __ of ______ ______. Additional fluid should be infused with extreme caution because excessive fluid administration exacerbates __ ____ ______, causes more profound RV ischemia, and worsens LV compliance and filling by causing further interventricular septal shift toward the LV.

Answer 37

500 mL; normal saline

RV wall stress

Question 38

________ and __________ are first-line inotropic agents for treatment of PE-related shock.

Answer 38

dopamine and dobutamine

Question 39

The preferred fibrinolytic regimen is 100 mg of recombinant ___ administered as a continuous peripheral intravenous infusion over _ _____. The sooner thrombolysis is administered, the more effective it is. However, this approach can be used for at least __ days after the PE has occurred.

Answer 39

tPA (tissue plasminogen activator)
2 hours
14

Question 40

Chronic thromboembolic pulmonary hypertension develops in _ - _% of acute PE patients. Therefore, PE patients who have initial pulmonary hypertension (usually diagnosed with Doppler echocardiography) should be followed up at about _ weeks with a repeat echocardiogram to determine whether pulmonary arterial pressure has normalized.

Answer 40

2 - 4%

6