Diagnostic Modalities and treatments

Question 1

Other modalities used other than U/S? (5)

Answer 1

Plain CT
Contrast arteriography
Magnetic resonance angiography(MRA)
Computed tomography(CTA)
Digital subtraction angiography (DSA)

Question 2

What is concidered the gold standard for preoperative assessment of patients for carotid intervention?

Answer 2

Arteriography

Question 3

Non-invasive diagnostic modality techniques? (3)

Answer 3

1. MRA
2. Duplex and TCD combined
3. CT

• No contrast used
• no catheter related complications

Question 4

What is arteriography?

• what 3 vessels does it assess
• complications associated?

Answer 4

• catheter based technique - invasive
• assesses the aortic arch, subclavian, and carotid arteries
• Stroke and death are reported complications in 0.2- 0.7% of patients

Question 5

What is plain CT?
- determines
evaluates
rules out

Answer 5

• Provides 2-D and 3-D images to identify silent infarcts
• determining the timing of surgery
• evaluates the risk of surgery
• rules out other causes of disease or symptoms

Question 6

what is CTA-computed tomography angiography?

Answer 6

Invasive
Administration of contrast dye
Highlights the cerebrovascularity

Question 7

What is digital subtraction angiography?

Answer 7

• method of choice for visualizing the entire cerebral arterial system
• Only vessels seen filled or unfilled
• Take a pre contrast image and inject dye into pre image and the other structures are subtracted out so only vessels remain

Question 8

what is MRA-magnetic resonance angiography?

• analyzes
• identifies
• less reliable than
• what is preferred

Answer 8

• Non-invasive technique for analyzing the carotid bifurcation
• Accurate in identifying carotid occlusion
• Less reliable than duplex doppler for categorizing stenosis in areas of moderate to severe narrowing
• Where flow is turbulent,it tends to overestimate disease
• Duplex and angiography are preferred first

Question 9

What is angioplasty?

Answer 9

• technique of mechanically widening a narrowed or obstructed artery

Question 10

how does angioplasty work?

Answer 10

• empty collapsed balloon on a guide wire (balloon catheter) is passed into the narrowed locations
• It is inflated to a fixed size using water pressures some 75-500 times normal blood pressure
• balloon forces expansion of the inner plaque deposits and the surrounding muscular wall, opening the blood vessel for improved flow
• Balloon is then deflated and withdrawn
• stent may be placed to ensure vessel remains open

Question 11

What is carotid stenting?

Answer 11

A catheter delivers a stent to a blocked artery

Frequently inserted at the same time as angioplasty

Question 12

importance of doppler post stent assessment?

Answer 12

• Placement of a stent can alter the biochemical properties
• This may cause an increase in velocities
• Some turbulence is expected
• PSV can increase throughout the patent (open to flow) stent area up to 150cm/s
• Gradual PSV increase is expected, but an abrupt increase is not normal

Question 13

How is doppler post-stent assessment completed?

Answer 13

• velocity increase seen across the stent at a 2:1 ratio identifies a degree of restenosis
• Must obtain present and poststent velocities
• The stent is assessed for intimal thickening, plaque formation or thrombus to diagnose restenosis
• Gray scale is useful to evaluate deformity in the stent-kinks, buckling etc.

Question 14

Criteria for CEA (endarterectomy) and CAS(stenting)?

Answer 14

• symptomatic patients with stenosis of 50% to 99%
• asymptomatic patients with stenosis of 60% to 99%
• perioperative risk of stroke and death in asymptomatic patients must be <3% to ensure benefit for the patient

Question 15

CAS should be reserved for what type of patient?

Answer 15

• symptomatic patients with stenosis of 50-99% at high risk for CEA for anatomic or medical reasons
• not recommended for asymptomatic patients

Question 16

How is CEA done?

Answer 16

• surgeon will make an incision in the neck to expose the blocked section of the carotid artery
• A clamp is placed on the artery to stop blood from flowing through it
• The surgeon will make a cut in the blocked part of the artery o remove the plaque, or will remove the inner lining of the artery around the blockage
• close the artery with stitches and stop any bleeding and then close the incision on the neck
• If the patient has small arteries or has already had a CEA, a patch may be placed over the cut in the artery which may reduce the risk of stroke for some patients

Question 17

During CEA procedure how does the brain get blood?

Answer 17

• the brain gets blood from the contralateral carotid artery
• A tube may also be used to shunt blood around the narrowed or blocked carotid artery

Question 18

Complications associated with CEA? (8)

Answer 18

1. Residual plaque at the end of the CEA site
2. Intimal flap
3. dissection
4. Occlusion
5. infected patch
6. hematoma
7. pseudoanurysm
8. restenosis

Question 19

Intimal flap?

Answer 19

• Disruption along the vessel wall with moving material observed within the lumen
• Disturbed color flow patterns and elevated PSV often present

Question 20

Aortic coarctation-CoA or COAo?

Answer 20

• The word “coarctation” means narrowing
• Coarctation of the aorta is a congenital condition whereby the aorta is narrow
• Most common in the aortic arch
• Usually in the area where the ductus arteriosus (ligamentum arteriosum after regression) inserts
• May be pre or post ductal

Question 21

Aortic coarctation-CoA or COAo detection?

Answer 21

• Difference of 70 mmHg or more between the brachial and ankle systolic pressures at rest
• may not have claudication and little or no change in ankle pressure following exercise
• This is due to the development of extensive collateralization that provides compensatory flow to the exercising muscles of the lower limbs