Week 11 - Angioplasty and Stents

Question 1

Where should you duplex if a pt has a LE stent?

Answer 1

Same locations for LE native arteries

Add Pre-stent, prox-stent, mid-stent- post-stent, post-stent

Question 2

Describe Percutaneous Transluminal Angioplasty

Answer 2

Catheter is inserted, Balloon is inflated rapidly over and over to push the atherosclerosis back, OR balloon inflates and sets stent into place

Question 3

When is Endovascular intervention preferred?

Answer 3

For focal (<5cm in length) regions of stenosis

Question 4

What does a Balloon angioplasty do, and how large is the lesion?

Answer 4

Dilates the lumen, <5cm stenosis or occlusion

Question 5

What does a Stent angioplasty do, and how large is the lesion?

Answer 5

Dilates the lumen, Focal and longer (>10 cm) stenosis or occlusion

Question 6

What does an atherectomy do, and how large is the lesion?

Answer 6

Plaque excision, Focal and longer (>10cm) stenosis

Question 7

What does a suboptimal angioplasty do, and how large is the lesion?

Answer 7

dilates the lumen, >10 stenosis or occlusion

Question 8

What does a stent-graft angioplasty do, and how large is the lesion?

Answer 8

Dilates the lumen, >15 cm stenosis or occlusion

Question 9

What is a common failure mode for all endovascular interventions? and what does it mean?

Answer 9

Myointimal Hyperplasia

smooth muscle cells of the arterial intima are over placed leading to an increased build-up of new cells

Question 10

How can you tell where a stent is placed using ultrasound?

Answer 10

look for bright lines in long and circumferential dots in trans

Question 11

How do you scan an area where an angioplasty was done?

Answer 11

Walk the sample volume through the area, measure PSVs, Observe velocity ratios
Velocity ratio >2 indicates >50% stenosis

Question 12

Angioplasty <50% Stenosis has what characteristics?

Answer 12

PSV = <180 cm/s
Vr = <2
EDS = N/A
Distal Waveform = Normal

Question 13

Angioplasty >50% Stenosis (moderate) has what characteristics?

Answer 13

PSV = 180-300 cm/s
Vr = 2-3.5
EDS = >0 cm/s
Distal Waveform = Monophasic

Question 14

Angioplasty >70% Stenosis (severe) has what characteristics?

Answer 14

PSV = >300 cm/s
Vr = >3.5
EDS = >45 cm/s
Distal Waveform = Damped, Monophasic, low velocity

Question 15

Angioplasty failure is defined as what?

Answer 15

Occlusion

>70% stenosis

Question 16

What are duplex findings on an in-stent stenosis?

Answer 16

Lumen reduction
Elevated PSV values (200-300 cm/s)
ABI reduction
Distal dampled, low-velocity waveform

Question 17

What are the LE Stent Criteria?

Answer 17

> 50% = PSV >180 cm/s, Ratio > 2.5
75-80% = PSV >275-300 cm/s, Ratio >3.5
No Color, No Doppler
Report disease as inside or outside the stent

Question 18

What is Surveillance protocol?

Answer 18

• Follow up of pt condition to check for post-intervention success
• identify PTA site abnormalities before failure

Question 19

What is post-intervention success criteria?

Answer 19

ABI increase >0.15
Resolution of ischemia signs and symptoms
<50% stenosis

Question 20

What are some post-interventional abnormalities?

Answer 20

In-site stenosis
Stent deformation
Myointimal hyperplasia
Thrombosis/occlusion

Question 21

Summarize what Duplex images you should do an Arterial LE stent

Answer 21

• Examine stented area inflow, across stent, and outflow with B-mode, color, and doppler
• Color flow for flow disturbance
• B-mode to check for inside or outside stent substances
• Doppler inflow, prox, mid, dist stent, outflow