Final

Question 1

In Poiseuille’s Law, what is the most important variable?

Answer 1

Radius (r), as it is to the 4th power

Question 2

Does Hunter’s canal (mid thigh) have a high or low incidence of atherosclerosis?

Answer 2

High.

Question 3

What is the cause of a greater ankle pressure than brachial pressure? Is it normal?

Answer 3

Systolic amplification is due to increasing arterial stiffness in smaller vessels, and is normal.

Question 4

Normal waveform for legs and arms at rest?

Answer 4

Triphasic

Question 5

How is hemodynamically significant defined?

Answer 5

As a drop in pressure and flow.

Question 6

What is the most important factor influencing the severity of an obstruction: diameter, length, or degree of irregularity?

Answer 6

Diameter.

Question 7

Where is the greatest energy loss, before or after a stenosis?

Answer 7

After - exit losses due to turbulence.

Question 8

How does circulation change as a stenosis develops?

Answer 8

Relaxin released, which dilates vessel.
Collaterals develop.
Peripheral runoff beds dilate to reduce resistance.

Question 9

What are the three components of collaterals?

Answer 9

Stem arteries (such as ECA, PFA)
Midzone collaterals
Re-entry vessels (frequently reversed).

Question 10

What are causes of pulsatility in the lower extremities?

Answer 10

CHF
Tricuspid regurgitation.
Fluid Overload.

Question 11

What technique can be used to demonstrate patency of the iliacs?

Answer 11

Valsalva maneuver - flow should stop during Valsalva, then resume afterward.

Question 12

50% diameter reduction is what % area reduction?

Answer 12

75%

Question 13

60% diameter reduction is what % area reduction?

Answer 13

90%

Question 14

What is the 2 cm rule?

Answer 14

If proximal portion of AAA is ≥ 2 cm beyond SMA origin, renal arteries are probably not involved.

Question 15

What resistive index criteria indicates parenchymal disease?

Answer 15

RI > 80

RI = (PSV - EDV)/PSV

Question 16

How much larger than the rest of the vessel need to be to be considered aneurysmal?

Answer 16

1.5 times

Question 17

What is the velocity criteria for SMA and Celiac for mesenteric ischemia?

Answer 17

SMA ≥ 275 cm/sec

Celiac ≥ 200 cm/sec

Question 18

What is the 2 artery rule for mesenteric ischemia?

Answer 18

Two of the three splanchnic arteries need to be stenosed or occluded.

Question 19

What are the criteria for portal hypertension? (6)

Answer 19

Flow < 15 cm/sec
Portal vein diameter > 13 mm
Splenomegaly > 13 cm
Waveform to-fro or reversed
Development of shunts
Hepatofugal flow

Question 20

What are the criteria for renal artery stenosis? (4)

Answer 20

Renal:Aorta velocity ratio > 3.5:1
PSV > 180 cm/sec
Acceleration time > 0.1
Loss of early systolic peak

Question 21

Size criteria for aortic and iliac aneurysm?

Answer 21

Aorta: > 3 cm
Iliac: > 1.5 cm

Question 22

After an exercise test, a pressure drop of what is considered diagnostic of PAD?

Answer 22

20 mmHg

Question 23

For SLP, a drop of what in legs segments is considered significant? Arms?

Answer 23

Legs: 30 mmHg
Arms: 20 mmHg

Question 24

At what ankle pressure does rest pain begin?

Answer 24

< 40 mmHg

Question 25

List the four ABI levels for Normal, Claudication, Multi-level, and rest pain.

Answer 25

Normal: > .96
Claudication: < .8
Multi-level: < .5
Rest pain: < .3

Question 26

When comparing ABI’s from earlier tests, or post exercise, what drop in ABI is considered significant?

Answer 26

0.15

Question 27

At what velocity ratio is a stenosis considered hemodynamically significant?

Answer 27

2:1

Question 28

What are the PSV and EDV velocity criteria for an 80-99% carotid stenosis?

Answer 28

PSV > 125

EDV > 100