Vascular Disease

Question 1

How do you perform a Buerger Test and what does it tell you?

Answer 1

Elevate pts foot (supine position) and wait for veins to drain; then put foot back. If turns white when elevated and then becomes very red when lowered, then positive sign for PAD.

Question 2

What is the ankle brachial index and how is it used? What’s normal?

Answer 2

• Ratio of ankle systolic BP over brachial systolic BP (detected with doppler probe)
• 1st step to evaluate degree of PAD in pt with claudication/atypical symptoms
• Normal is 0.9-1.0 (lower or higher means PAD or calcified/non-compressible)

Question 3

Why is transcutaneous 02 measurement used in diagnosis of PAD?

Answer 3

May aide in assessing healing potential

Question 4

Would you use ultrasound to diagnosis PAD? Why?

Answer 4

Yes, could use to estimate extent of disease or stenosis in arms and legs

Question 5

Why might you do an MRA to diagnosis PAD? Why not?

Answer 5

• Time-efficient, cost effective
• Usually only done when revascularization being considering
• DON’T do in pts with renal failure because the contrast (gadolinium) can cause nephrogenic systemic sclerosis

Question 6

What is the gold standard for evaluating a threatened limb in PAD?

Answer 6

Contrast arteriography

(Note: this is not necessary for diagnosing PAD but is used to look at limbs to see where occlusion is for pts expected to undergo revascularization)
Could be used therapeutically if see a problem (e.g. put in stent, angioplasty etc)

Question 7

Why would you consider a CO2 angiography?

Answer 7

To diagnosis pt with PAD who has renal disease or is allergic to the typical contrast; CO2 displaces blood so can see on fluoroscopy

Note: quality of image may be slightly less

Question 8

What tests would you use to diagnose venous reflux?

Answer 8

• Duplex ultrasound (easy, non-invasive, high sensitivity and specificity; will show latency of vein and direction of flow)
• Venography (classic gold standard)

Question 9

What is the Wells Criteria?

Answer 9

Estimates probability that pt has DVT using point system

Examples:
-Active Cancer +1
-Calf swelling >3cm compared to other leg +1
-Immobilization >3days or surgery in previous 4 weeks +1
(more on table in notes)

Only negative points: Alternative diagnosis as likely or more likely than DVT -2

Question 10

What is a d-dimer lab test?

Answer 10

• Used to evaluate for DVT; D-dimer is small protein fragment in blood after blood clot is degraded by fibrinolysis
• 95% sensitive so if negative, extremely unlikely pt has a clot => NO FURTHER WORK UP
• However can be elevated in other conditions so is mainly used to exclude thrombosis

Question 11

What is first line imaging for DVT?

Answer 11

Duplex ultrasound - accessible, non-invasive, high sensitivity and specificity
(Contrast venography is gold standard but more invasive)

Question 12

So how should we diagnose a DVT? In what cases do we use the different diagnostic tools?
(Low pretest probability steps vs. high pretest probability steps)

Answer 12

• Low pretest (i.e. Wells 0-1): Check d-dimer; if negative then not DVT
• Mod–High (Wells >2): Skip d-dimer; go straight to ultrasound of legs and consideration of PE testing if indicated

Question 13

Should I order a hypercoagulation panel for DVT?

Answer 13

• NO if it was initial DVT and was provoked; usually no even if unprovoked DVT unless pt is young, family hx of VTE
• But even if order, full panel can’t be drawn until after initial anticoagulation course is complete