Vascular- Hemodialysis & Midterm Review Questions

Mals

what patients is hemodialysis designed for?

patients with end stage renal disease

what is the function of hemodialysis?

to remove waste products, creatinine, urea and excess water for those with nonfunctioning kidneys

which arm should BP be taken on a patient with a fistula or who has had lymph node removal in the arm?

the side that does not have the fistula/previous intervention

what does a palpable fistula "thrill" sound like?

turbulent flow

this indicates the fistula is working properly

what are the 3 major types of access for dialysis?

central venous catheter

synthetic AV bridge graft

primary AV fistula

what is the site of insertion for a central venous catheter (2 options) ?

IJV

subclavian vein

is a central venous catheter a temporary or permanent access?

temporary

how is a primary AV fistula created?

with a surgical procedure to connect an artery to a vein

a primary AV fistula is usually created where on the body?

the lower arm

why is a primary AV fistula also reffered to as a "native" fistula?

because it uses the persons own vessels and no synthetic material

a primary AV fistula is created on which arm?

dominant arm

why is a primary AV fistula created on the non-dominant arm?

to reduce the risk of injury to the graft

what is the most common vessels connected with a primary AV fistula?

radial artery with the cephalic vein

how long can AVFs last for?

long term patency as they have a low complication risk

how long does it take for an AVF to mature?

3-4 months

what 3 things must occur for an AVF to be fully "mature"

1. blood volume through the vessels must increase

2. vessels must increase in diameter

3. vein wall must thicken

which vessel in an AVF is used for dialysis puncture?

the superficial efferent vein

(cephalic)

why does the superficial vein in an AVF become lumpy and sausage like?

due to increased pressure

why are flow volumes difficult to obtain in a AVF superficial vein>

because the superficial vein has an inconsistent diameter throughout

the efferent vein carries blood _______ from the heart

heart

if a patients vessels are not suitable to make a primary AVF, what other option can be used?

a synthetic bridge graft using a tube to connect the artery with the vein

with a synthetic bridge graft, where are the needles inserted?

into the graft material instead of the vein

around ____% of patients are not candidates for AVF

50

what material is used to create a synthetic bridge graft?

teflon

synthetic bridge graft material has a smaller tapered diameter on the _______ side to reduce flow volume

arterial

what is a type of material that can be used for synthetic grafts, but is not seen on US?

polyurethane

why are synthetic grafts not preferred over AVF?

they have a shorter duration and lower patency rates

if a fistula or graft fails, where can they create a new one in relation to the failed one?

anywhere using more proximal vasculature (so they move up the arm)

what are some complications of grafts & fistulas? (3)

thrombosis

occlusion

stenosis

what can arterial steal result in?

digit or hand ischemia

what causes distal venous hypertension with a graft or fistula?

reversal of venous flow

grafts and fistulas can cause ____ sided heart pressure due to excessive graft flow

right

do infections more often occur with AVFs or synthetic grafts?

synthetic grafts

vessels for AVF must be ____mm or greater to be used

2

if you're evaluating the patency of vessels for a patient getting an AVF, what position should they be scanned in?

sitting up- so it forces blood to pool in the arms

what will doppler signals on the feeding artery look like with a graft or fistula?

monophasic

lots of diastole

what will doppler signals look like in the anastamoses of a graft or fistula?

turbulent flow over a long stretch

what will doppler signals look like on the draining vein with a graft or fistula?

pulsatile flow that's arterialized

the volume flow on doppler in a graft or fistula should be greater than ____ml/min

500

how do we calculate a stenosis ratio in an AVF?

highest velocity in stenosis / most normal proximal velocity

what are some common indications for an ultrasound of a graft or fistula?

difficulty with needle placement

increased dialysis time

pain, swelling, discoloration

palpable mass

abnormal labs

increased venous pressure

what will the walls of a synthetic graft look like on US?

echogenic

what type of probe do we use to assess grafts or fistulas?

high resolution linear

in a graft or fistula US, we assess ___cm below and above the feeding artery and draining vein

2

a PSV ratio over 2 in a graft or fistula suggests a ____% or greater stenosis

50

a PSV ratio over 3 in a graft or fistula suggests a _____% or greater stenosis

75

after a stenosis finding in a graft or fistula on ultrasound, what other imaging is used to confirm it?

angiogram (CTA)

how is complete arterial steal with a graft confirmed using doppler?

direction of flow will be reversed superior to the graft

how is partial arterial steal with a graft confirmed using doppler?

spectral waveform will be biphasic

severely symptomatic arterial steal patients may require what type of intervention?

graft ligation (closure of the graft)

intimal wall thickening is diagnosed with an intima measurement of over ____mm

0.9

what is the formula for obtaining ICA ratios?

prox ICA / dist CCA

using an angle correct over 60 degrees will _____estimate the velocities and the ratios

over

____% of cross-sectional area of the aorta must be encroached upon before there's change in distal pressure and flow

90

what plane is vessel area measurements taken in?

transverse

what is the formula for calculating area reduction?

1 - (residual/original) x 100

what plane is diameter reduction measurements taken in?

saggital

what is the formula for calculating diameter reduction?

1 - (residual/original) x 100

diameter reductions of over ___% are considered hemodynamically significant

50

area reductions of over ___% are considered hemodynamically significant

70

what 3 ankle BP locations are obtained for ABIs?

posterior tibial artery

peroneal artery

dorsalis pedis artery

what is the ABI formula?

highest brachial systolic BP / highest ankle systolic BP (on each side)

an ABI of under ____ indicates severe disease

0.5

an ABI of under ____ indicates ischemic rest pain will be present

0.3

an ABI of over _____ is normal

0.9

what will be the normal waveforms in a fasting SMA?

high resistance

low diastolic flow

what will be the normal waveforms in a non-fasting SMA?

lower resistance with more diastolic flow than the fasting state

will pressure increase or decrease following a stenosis?

decrease

in SSS, which arm will have the lower BP?

the diseased arm

which artery commonly reverses to become a collateral in ICA stenosis or occlusion?

opthalmic artery

will tachycardia increase or decrease PSVs?

decrease

a stroke is characterized by motor deficits lasting longer than ___ hours

24

what are some typically symptoms of disease in the ICA?

decreased conciousness

paralysis

amourosis fugax

vertigo is a neurological symptom due to atherosclerosis in which part of the brain?

posterior circulation

the tunica media layer of an artery is made of what?

muscle and connective tissue

how would you describe "variable plaque morphology" ?

heterogenous with anechoic areas

where do all cerebrovascular vessels arise from?

the aortic arch

what term can be used to describe flow in the CCA?

laminar

what is the first major branch off the ICA?

opthalmic artery

what are non-plaque causes of turbulent flow?

increases in diameter

kinking or coiling

does the ICA have branches in the cervical section?

no- all branches are intracranial

critical stenosis symptoms begin with a ___% decrease in diameter

70

what is another term for carotid body tumours?

paragangliomas

the extracranial posterior circulation is composed of which vessels?

vertebrals

the verterobasilar system supplies ___-___% of intracranial flow

20-30

what artery supplies the brainstem?

basilar

pulse biferans also known as the double peak sign is seen in what pathology?

aortic regurgitation

where is plaque usually taken out in a carotid endarterectomy?

bulb and bifurcation

what are the anatomical boundaries of thoracic outlet syndrome?

scalene muscle

clavicle

1st rib

mechanical compression of an artery is called what?

entrapment syndrome

what are the symptoms of leriche syndrome?

claudication in buttock area

decreased LE pulses

impotence