Collateral Circulation Flashcards Preview

Vascular II > Collateral Circulation > Flashcards

Flashcards in Collateral Circulation Deck (23)
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1
Q

____% of cardiac output supply the brain

A

15%

2
Q

___% CCA blood goes to the ICA

A

80%

3
Q

*The most common collateral pathway involves (1)

A

The circle of Willis

4
Q

*What is the second most important route of collateral flow?

A

Peri-orbital circulation

5
Q

Peri-orbital branches of the ICA (3)

Can communicate with (2)

A

Peri-orbital branches:

  • Frontal A
  • Supraorbital A
  • Nasal artery A

Communicate with:

  • Superficial temporal A
  • Facial A
6
Q

The intracranial-extracranial anastomoses occur between (2)

A

Orbital branch of superficial temporal (ECA branch)
+
Opthalmic A (ICA branch)

7
Q

Only ____% of patients have complete Circle of Willis

A

50%

8
Q

What are the 3 major collateral routes

A

Circle of Willis
Posterior cerebral circulation
ECA branches

9
Q

Some patients don’t reveal any symptoms of cerebrovascular disease even with total occlusion of both ICAs

A

True -

10
Q

How do collaterals develop?

A

Because of a change in pressure gradient between the vessels caused by a stenosis

11
Q

Cellular death can occur in _____ mins

A

3-8 mins

12
Q

In hemodynamics, what is the most limiting?

A

Width - poiseuille’s law

13
Q

Will blood take a long wide path or a short narrow path?

A

Long & wide

14
Q

Adequate arterial perfusion relies on (3)

A

Blood pressure
Cardiac output
Blood volume

15
Q

The vertebral-basilir system provides how much cerebral blood flow

A

20-30%

16
Q

Normal Vertebral A flow:

velocity & waveform

A

Low resistant, monophonic, large EDV

20-60 cm/s

17
Q

What is the least likely level for VA to be diseased?

A

Mid portion

18
Q

What side VA is more commonly larger?

A

Left more common than right

19
Q

Vertebral flow:
Abnormal traits &
What can this imply (2)

A

High resistant flow with no diastolic waveform

Implies: distal VA stenosis/occlusion, hypoplastic VA

20
Q

S/S VA disease (2)

A

Dizziness & unsteady walking

21
Q

What side is SSS most commonly seen?

A

Left side

22
Q

what arteries can SSS involve? (3)

A

RT subclavian A
LT subclavian A
INN A

23
Q

What will you see with SSS? (Describe SCA, Brachial A, VA)

A
-SCA
high PSV >500 cm/s
Short low-resistant path becomes high resistant due to narrowing
Loss of tri-phasic signal
Aliasing
Damped flow distally (monophonic)
  • Decreased ipsilateral (same side) brachial artery systolic BP - (20-40 mmHg pressure difference between arms)
  • Reversed flow ipsilateral VA to supply the arm