THROMBOEMBOLISM (PE and DVT)

Question 1

The highest-risk surgeries for VTE include

Answer 1

abdominal surgery to remove cancer,
joint replacement surgery,
surgery on the brain or spinal cord in the setting of neurologic deficits.

Question 2

Risk Factors for Venous Thromboembolism (VTE)

Answer 2

1 Age Risk becomes significant at 50 y and increases with each year of life until age 80 y.
2 Obesity Risk starts at BMI >35 kg/m2 and increases with increasing BMI.
3 Pregnancy Risk increases with trimester (but overall risk remains low throughout pregnancy).
4 Solid cancers Risk greatest with adenocarcinomas and metastatic disease. A history of remote, inactive cancer probably does not increase risk.
5 Hematologic cancers Acute leukemias confer the greatest risk.
6 Inherited thrombophilia Factor V Leiden and familial protein C deficiency have the strongest risk.
7 Recent surgery or major trauma Risk continues at least 4 wk postoperatively or after trauma intensive care.
8 Immobility Acute limb immobility confers the highest risk.
9 Bed rest Becomes a risk factor at approximately 72 h.
10 Indwelling catheters Cause approximately one half of arm deep venous thromboses.
11 Long-distance travel Published data are controversial.
12 Smoking Not a risk factor itself, but may increase risk of other factors such as oral contraceptives.
13 Congestive heart failure Related primarily to severity of systolic dysfunction.
14 Stroke Risk greatest in first month after deficit.
15 Estrogen All contraceptives containing estrogen increase risk of VTE.
16 Noninfectious inflammatory conditions Examples are inflammatory bowel disease, lupus, nephrotic syndrome. Risk of VTE increases roughly in proportion to severity of underlying disease.

Question 3

In PE, Proximal clots cause …. and dyspnea; distal clots cause …..

Answer 3

ventilation/perfusion mismatch

infarction with pain

Question 4

A difference of … between right and left leg diameter 10 cm below the tibial tubercle is predictive of DVT

Answer 4

2 cm

Question 5

Wells Score for Pulmonary Embolism (PE)

Answer 5

Factor	Points*
Suspected deep venous thromboses	3
Alternative diagnosis less likely than PE	3
Heart rate >100 beats/min	1.5
Prior venous thromboembolism	1.5
Immobilization within prior 4 wk	1.5
Active malignancy	1
Hemoptysis	1

Question 6

Wells Score for Deep Venous Thrombosis

Answer 6

Clinical Feature Points*
Active cancer (treatment within 6 mo, or palliation) 1
Paralysis, paresis, or immobilization of lower extremity 1
Bedridden for >3 d because of surgery (within 4 wk) 1
Localized tenderness along distribution of deep veins 1
Entire leg swollen 1
Unilateral calf swelling of >3 cm (below tibial tuberosity) 1
Unilateral pitting edema 1
Collateral superficial veins 1
Alternative diagnosis as likely as or more likely than deep venous thrombosis 2

Question 7

The D-dimer has a half-life of approximately …., and the D-dimer level probably remains abnormally high for at least …. after symptomatic VTE.

Answer 7

8 hours

3 days

Question 8

Potential False Positive Levels of D-Dimer

Answer 8

Age >70 y	
Pregnancy	
Active malignancy or metastasis	
Surgical procedure in previous week	
Liver disease	
Rheumatoid arthritis	 
Infections	 
Trauma

Question 9

Potential False Negative Levels of D-Dimer

Answer 9

Warfarin treatment
Symptoms lasting over 5 d
Presence of small clots
Isolated small pulmonary infarction
Isolated calf vein thrombosis

Question 10

Pulmonary Embolism Rule-Out Criteria (PERC Rule)

Answer 10

Age 94% (breathing room air)

Heart rate

Question 11

If the ED clinician has access to a …., it should be strongly considered as a first diagnostic test in patients for whom clinical suspicion is low or moderate based on either gestalt estimation, a Wells score of

Answer 11

quantitative D-dimer assay

Question 12

For extensive superficial vein thrombophlebitis, …. is recommended.

Answer 12

anticoagulation

but at the lower, prophylactic dose (i.e., enoxaparin, 40 milligrams SC daily).

Question 13

Massive PE

Answer 13

is PE with a systolic blood pressure of 15 minutes, or a systolic blood pressure of 40% reduction in baseline systolic blood pressure.

Question 14

Submassive PE is characterized

Answer 14

by a normal or near-normal blood pressure, but with other evidence of cardiopulmonary stress

Question 15

Indication for fibrinolysis in PE

Answer 15

1 patients with cardiac arrest at any point;
2 patients with arterial hypotension fulfilling criteria for massive PE;
3 patients with respiratory failure, evidenced by severe hypoxemia (pulse oximetry reading

Question 16

Major contraindications to thrombolytic therapy include

Answer 16

intracranial disease,
uncontrolled hypertension at presentation,
recent major surgery or trauma (past 3 weeks),
metastatic cancer.

Question 17

Indications for Hospital Admission in Patients with Deep Venous Thrombosis

Answer 17

1 An extensive iliofemoral deep venous thrombosis with circulatory compromise
2 An increased risk of bleeding (coagulopathy, active peptic ulcer disease, liver disease) that requires close monitoring of therapy
3 A limited cardiorespiratory reserve
4 A risk of poor compliance with home therapy regimen or inadequate support (i.e., community, social, or medical), or concern with ability to arrange follow-up
5 A contraindication to use of low-molecular-weight heparin, which would necessitate IV heparin therapy
6 Coexistent pulmonary embolism
7 A high suspicion of heparin-induced thrombocytopenia without or with thrombosis
8 Renal insufficiency requiring monitoring of anti-Factor Xa level, or use of unfractionated heparin

Question 18

D-dimer assay can be ordered for pregnant patients and that the threshold for considering the concentration abnormal should be increased according to the trimester of pregnancy as follows:

Answer 18

first trimester, 750 nanograms/mL;
second trimester, 1000 nanograms/mL;
third trimester, 1250 nanograms/mL.