Venous Thromboembolism

Question 1

What is the cause done VTE after major surgery?

Answer 1

Thromboplastin release

Question 2

What are the medical conditions with the highest risk of VTE?

Answer 2

Right heart failure
Stroke with lower extremity weakness
Cancer

Question 3

What is responsible for the variable anticoagulant effect of heparin?

Answer 3

Plasma protein levels

Heparin binds these, macrophage, and endothelial cells. This messes with its bioavailability

Question 4

What is the MOA of unfractionated heparin?

Answer 4

Bind to antithrombin III and this complex inactivates factor 2a (thrombin) and Xa

Question 5

What is the standard dosing of LDUH?

Answer 5

5,000 units q8 or q 12

Question 6

What are the advantages of LMWH?

Answer 6

1. More potent anticoagulant
2. More predictable effect
3. Longer duration of action (doesn’t bind endothelial cells or macrophage)
4. Reduced binding of platelets (lower risk of HIT)

Question 7

What is the disadvantage of LMWH?

Answer 7

Cleared renally

Question 8

What type of surgeries is LMWH superior to LDUH for?

Answer 8

Major orthopedic surgery

Question 9

What is the dosage of enoxaparin in obese patients?

Answer 9

0.5 mg/kg

Question 10

What are the advantages of dalteparin over lovenox?

Answer 10

Given only once daily in higher doses

Can be continued without dose reduction in renal failure

Question 11

How long should you hold LMWH before an epidural?

Answer 11

If twice a day dosing - 12 hours

If once a day dosing - 24 hours

Question 12

How long do you wait after an epidural to restart LMWH?

Answer 12

2 hours

Question 13

How do graded compression stockings work?

Answer 13

Create a gradient of external pressure to force venous outflow of the legs

Question 14

Can graded compression stockings be used alone for thromboprophylaxis?

Answer 14

No

Question 15

Can intermittent pneumatic compressions be used alone?

Answer 15

Yes

Question 16

What are the clinical symptoms of PE?

Answer 16

Tachypnea, tachycardia, hypoxemia, dypsnea

Question 17

What is the principal method for finding venous thrombosis in the leg?

Answer 17

Compression us

Question 18

What technique can be used as adjunct for identifying thrombosis?

Answer 18

Color Doppler US

Question 19

What is the test of choice for an upper extremity clot?

Answer 19

Venous US

Question 20

What can be missed in a CTA?

Answer 20

Smaller, segmental clots

Question 21

How do you manage a PE?

Answer 21

Bolus of IV heparin

Question 22

What is the target PTT?

Answer 22

46-70 seconds

Question 23

What is the target PTT ratio test?

Answer 23

1.5-2.5

Question 24

When does HIT appear?

Answer 24

5-10 days afte the initiation of heparin therapy

Question 25

What can reverse heparin?

Answer 25

Protamine sulfate

Question 26

How much protamine would you give?

Answer 26

1 mg covers 100 units If been running for 30 minutes - do 0.5 mg per 100 units If been running for more than 2 hours - do 0.27-0.375 mg per 100

Question 27

How would you dose protamine for a continuous heparin infusion?

Answer 27

Use the heparin dose that ran over last 2 hours and give 1 mg per 100

Question 28

What does protamine cause?

Answer 28

Bradycardia Hypotension Hypersensitivity (ask about fish products)

Question 29

How can use asses the effectiveness of protamine?

Answer 29

Get activated PTT 5-15 minutes after administration

Question 30

How can you avoid Brady and hypotension when giving protamine?

Answer 30

Give it slowly over 10 minutes

Question 31

What is the therapeutic dose of LMWH for a PE?

Answer 31

1 mg/kg q 12 h

Question 32

How do you monitor the effect of LMWH?

Answer 32

Anti-Xa levels

Question 33

What is the desired range of anti-Xa for clot?

Answer 33

0.6-1 unit/ml if twice a day dosing | Over 1 if once a day

Question 34

Why is continuous heparin infusion the treatment modality if choice for PE?

Answer 34

Rapid acting Easily reversible Doesn't require dose adjustment in renal patients

Question 35

What is the initial dose of warfarin?

Answer 35

5-10 mg for first 2 days

Question 36

What is the standard thrombolytic regimen?

Answer 36

Alteplase 100 mg infused over 2 hours

Question 37

What is the goal thrombolytic therapy for a PE?

Answer 37

Limit clot extension Does not break up existing clot Can reduce right heart strain

Question 38

What are the indications for thrombolytic therapy?

Answer 38

Hemodynamic deterioration and RV dysfunction

Question 39

What are the indications for an IVC filter?

Answer 39

Absolute contraindication to anti coagulation PE during full anticoag A large free-floating thrombus Limited cardiopulmonary reserve

Question 40

What is the shape and name of the filter used?

Answer 40

Greenfield filter, looks like a bad mitten birdie | Allows it to fill without compromising the lumen of the IVC

Question 41

How are IVC filters inserted?

Answer 41

Percutaneously through the IJ or femoral vein

Question 42

Where in the IVC is it placed?

Answer 42

Below the renal veins

Question 43

What are the risk factors for VTE.

Answer 43

``` Surgery Trauma Malignancy Estrogen drugs EPO Acute medical illness Prior hx Obesity Pregnancy Sepsis Vasopressors Platelet transfusions Immobility ```