Ch 300: Deep Venous Thrombosis and Pulmonary Thromboembolism Flashcards
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.
factor V Leiden
prothrombin gene mutation
What is the most common acquired cause of thrombophilia?
Antiphospholipid antibody syndrome
Virchow’s triad consist of…
…inflammation, hypercoagulability, and endothelial injury.
What 3 substances are naturally occurring coagulation inhibitors?
Antithrombin, protein C, and protein S
Paradoxically, these thrombi in the heart occasionally embolize to the arterial circulation through a…
…patent foramen ovale or atrial septal defect.
In the patient with a PE, physiologic dead space increases because…
…ventilation to gas exchange units exceeds venous blood flow through the pulmonary capillaries.
Leg DVT is about __ times more common than upper extremity DVT,
10
Low-risk PE constitutes about what % of cases?
70 - 75%
Lower extremity DVT usually begins…
and propagates…
…in the calf
…proximally to the popliteal vein, femoral vein, and iliac veins.
Superficial venous thrombosis usually presents with…
…erythema, tenderness, and a “palpable cord.”
Patients with a low-to-moderate likelihood of DVT or PE should undergo initial diagnostic evaluation with…
…d-dimer testing alone without obligatory imaging tests.
However, for patients with a high clinical likelihood of VTE…
…skip d-dimer testing and undergo imaging as the next step in the diagnostic algorithm.
Not all leg pain is due to DVT. Sudden, severe calf discomfort suggests a…
…ruptured Baker’s cyst.
Pulmonary infarction usually indicates a small PE. This condition is exquisitely painful because…
…the thrombus lodges peripherally, near the innervation of pleural nerves.
What rare type of embolisms can occur after total hip or knee replacement?
Cement embolism and bony fragment embolism
Which clotting factors does activated protein C inactivate?
Factors V and VIII
RV wall tension also compresses the right coronary artery, limits myocardial oxygen supply, and precipitates…
…right coronary artery ischemia and RV microinfarction, with release of cardiac biomarkers such as troponin.
The quantitative plasma d-dimer enzyme-linked immunosorbent assay (ELISA) rises in the presence of DVT or PE because…
…of the breakdown of fibrin by plasmin.
D-dimer rarely has a useful role among hospitalized patients, because levels are…
…frequently elevated due to systemic illness.
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 __.
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
What is Westermark’s sign?
focal oligemia – radiographic sign of PE
What is Hampton’s hump?
a peripheral wedged-shaped density above the diaphragm – radiographic sign of PE
What is Palla’s sign?
an enlarged right descending pulmonary artery – radiographic sign of PE
RV enlargement on chest CT indicates an increased likelihood of death within the next…
…30 days compared with PE patients who have normal RV size.
A high-probability scan for PE is defined as…
…two or more segmental perfusion defects in the presence of normal ventilation.
_____ ____ ________ of patients with angiographically confirmed PE have a high probability V/Q scan.
Fewer than one-half
The best-known indirect sign of PE on transthoracic echocardiography is __________ sign: hypokinesis of the RV free wall with….
McConnell’s
normal or hyperkinetic motion of the RV apex.
Anticoagulation or placement of an inferior vena caval filter constitutes _________ prevention of VTE.
secondary
When RV function remains normal in a hemodynamically stable patient with PE, a good clinical outcome is highly likely with…
….anticoagulation alone.
What is one benefit of fondaparinux?
It does not cause heparin-induced thrombocytopenia.
Warfarin is a vitamin K antagonist that prevents carboxylation activation of what coagulation factors?
II, VII, IX, and X
___________, a factor Xa inhibitor, is approved for treatment of acute DVT and acute PE as monotherapy, without a parenteral “bridging” anticoagulant.
Rivaroxaban
There is no specific ________ _____ for bleeding caused by fondaparinux, direct thrombin inhibitors, or factor Xa inhibitors.
reversal agent
Major bleeding from warfarin is best managed with ___________ _______ ___________. With serious but non–life-threatening bleeding, _____-______ ______ or ___________ _______ _ can be used.
prothrombin complex concentrate
fresh-frozen plasma or intravenous vitamin K
What is the minimum duration of anticoagulation for patients with one episode of DVT?
3 months
The two principal indications for insertion of an IVC filter are:
(1) active bleeding that precludes anticoagulation
(2) recurrent venous thrombosis despite intensive anticoagulation
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.
500 mL; normal saline
RV wall stress
________ and __________ are first-line inotropic agents for treatment of PE-related shock.
dopamine and dobutamine
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.
tPA (tissue plasminogen activator)
2 hours
14
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.
2 - 4%
6
