Week 11 - Angioplasty and Stents Flashcards
(21 cards)
Where should you duplex if a pt has a LE stent?
Same locations for LE native arteries
Add Pre-stent, prox-stent, mid-stent- post-stent, post-stent
Describe Percutaneous Transluminal Angioplasty
Catheter is inserted, Balloon is inflated rapidly over and over to push the atherosclerosis back, OR balloon inflates and sets stent into place
When is Endovascular intervention preferred?
For focal (<5cm in length) regions of stenosis
What does a Balloon angioplasty do, and how large is the lesion?
Dilates the lumen, <5cm stenosis or occlusion
What does a Stent angioplasty do, and how large is the lesion?
Dilates the lumen, Focal and longer (>10 cm) stenosis or occlusion
What does an atherectomy do, and how large is the lesion?
Plaque excision, Focal and longer (>10cm) stenosis
What does a suboptimal angioplasty do, and how large is the lesion?
dilates the lumen, >10 stenosis or occlusion
What does a stent-graft angioplasty do, and how large is the lesion?
Dilates the lumen, >15 cm stenosis or occlusion
What is a common failure mode for all endovascular interventions? and what does it mean?
Myointimal Hyperplasia
smooth muscle cells of the arterial intima are over placed leading to an increased build-up of new cells
How can you tell where a stent is placed using ultrasound?
look for bright lines in long and circumferential dots in trans
How do you scan an area where an angioplasty was done?
Walk the sample volume through the area, measure PSVs, Observe velocity ratios
Velocity ratio >2 indicates >50% stenosis
Angioplasty <50% Stenosis has what characteristics?
PSV = <180 cm/s
Vr = <2
EDS = N/A
Distal Waveform = Normal
Angioplasty >50% Stenosis (moderate) has what characteristics?
PSV = 180-300 cm/s
Vr = 2-3.5
EDS = >0 cm/s
Distal Waveform = Monophasic
Angioplasty >70% Stenosis (severe) has what characteristics?
PSV = >300 cm/s
Vr = >3.5
EDS = >45 cm/s
Distal Waveform = Damped, Monophasic, low velocity
Angioplasty failure is defined as what?
Occlusion
>70% stenosis
What are duplex findings on an in-stent stenosis?
Lumen reduction
Elevated PSV values (200-300 cm/s)
ABI reduction
Distal dampled, low-velocity waveform
What are the LE Stent Criteria?
> 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
What is Surveillance protocol?
- Follow up of pt condition to check for post-intervention success
- identify PTA site abnormalities before failure
What is post-intervention success criteria?
ABI increase >0.15
Resolution of ischemia signs and symptoms
<50% stenosis
What are some post-interventional abnormalities?
In-site stenosis
Stent deformation
Myointimal hyperplasia
Thrombosis/occlusion
Summarize what Duplex images you should do an Arterial LE stent
- 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