rest for final Flashcards
patients who complain of claudication only with exercise (intermittent claudication) usually have an ABI close to what?
ABI of 1.0 prior to exercise and an ABI in the 0.6 to 0.8 range following exercise and therefore require additional testing
why does exercise result in temporary limb ishemia?
diseased arterial tree’s inability to supply flow during the limb’s increased flow requirements
what is done before exercise testing?
obatin resting brachial and ankle pressures before exercising
how long should the patient walk for in exercise testing?
5 minutes or untill the onset of claudication
what should be done if the exercise pain causes the patient to stop?
patient is returned to the exam table and rests in a supine position
what is done within the first minute after stopping the treadmill?
the brachial and ankle pressures are repeated within the first minute after stopping the treadmill
how long do you test the ankle brachial pressure?
if pressure drop in detected in the minute after exercise then it should be repeated 2-3 times intervals up to 20 minutes until the ankle pressure returns to pre exercise levels
what pressure after exercise should a normal person have?
no drop in ankle pressure following exercise and may in fact show a slight increase in pressure
patients with arterial disease demonstrate what type of pressure after exercising?
fall in pressure to a poin below the pre-excersie level
what is the drop in pressure after exercise proportional to?
to the degree of arterial disease
how is drop in pressure after excerise assessed?
by the magnitude of immediate pressure drop following exercise and the length of time required for the ankle pressure to return to the pre-exercise level
when is there a probably single level disease?
if the ankle pressue returns to normal in a period of 2-6 minutes
when is there probably atherosclerotic disease present at multiple levels?
if the return pressure requires up to 12 minutes
when is it considered the patient has ischemic pain?
patients suffering from ischemic rest pain require more than 15 minutes to return to pre-exercise levels
what is pseudoclaudication?
patients suffer from intermittent claudication and their pressure remains normal then they should be investigsted for possible muscoskeletal or neurospinal disorders
when is reactive hyperemia testing done?
used to stress patients who are not capbale of preforming a treadmill test (physical instability, heart issues, etc)
when is reactive hypemia testing not useful?
in patients who demonstrate an abnormal resting ABI
when should reactive hyperemia testing only be used?
evaluate patients who demonstrate a normal resting ABI who complain of pain with exertion
what is used to stress a patient?
treatmill tesing
what is the technique of treatmill testing?
measuring the patients ankle pressure following temporary (3 min) leg ischemia caused by the application of a thigh tourniquet or cuff
in treadmill testing, are both legs done or just 1?
1 leg at a time
how much is the thigh cuff inflated?
30 mmHg above systolic pressure for a period of 3 minutes
how many second intervals is the ankle pressure obtained?
15 second intervals until the pre-exercise pressure is obtained
when do normal patients have a drop in ankle pressure?
transient drop following reactive hyperemia
when do normal patients return to pre-exercise levels?
within 30-60 seconds
in normal patients ankle pressure taken immediately after occlusion falls no more than ___ below resting level
35%
how long do patients with significant occlusive disease require to return to pre-exercise levels?
require more than 1 minute to return
what is the pressure drop in a single level disease?
<50% pressure drop
what is the pressure drop in a multilevel disease?
> 50% pressure drop
who may be impossible to preform hyperemia reactive testing?
very obese patinets
who do we not choose to preform hypermia testing on?
patients who have under gone recent bypass surgery due to pain and fear of occluding the graft
is hypermia pain less?
no its uncomfortable
the venous sytem of the lower limbs in fragile and easily damaged by what?
- thrombosis
- trauma
- inflammation
when thrombus doesnt clear completely, what can it result in?
chronic obstruction and damage to the valves
In limbs affected by DVT _____ had at least one segment of incompetent vein
69%
what does damage of the lower veins result in?
the loss of the protective action of the valves creating a constant column of blood between the heart and tissues if the calf, ankle, and foot
what is a gaiter area?
ulcer in medial foot (check notes)
in the erect position varicose veins may extend over how long?
1.25 meters
what does hydroststic pressure exerted in the tissues interfere with?
circulation of blood in the capillaries
what does no blood in capillaries affect?
transfer of nutrients and waste matter between blood and tissues
what may no blood in capillaries promote?
local inflammatory responces such as varcose veins, pigmentation, and ulceration
the pattern of damaged and incompetant valves can be defines with?
doppler US
what can be mapped out?
incompetent venous segments and incompetent perforating veins
what does mapping allow for?
appropriate surgical or medical interventions techniques to be applied
when may reccurance of varicose veins occur?
after surgery or scleotherapy
vein ablation
a heated cathedar is placed within the affected vein essentially closing it
sclerotherapy/compression stockings
a solution is injected into the varicose vein, drying it up
what are the 3 main patterns of recurrence for varicose veins?
1-a patent long saphenous vein may be present suggesting that it may have been missed at the time of operation
2-small collateral veins along the ling of the long saphenous vein may enlarge to reconstitute the path of the vein
3-drainage can occur through venous collaterals which take a variety of courses remote from the normal line of the vein
what is useful to assess the pattern of recurrence of varcicose veins?
color doppler so that appropriate surgical intervention may be planned
how many tributaries drain into the LSV at the level of the SFJ?
6
what can tributaries of the LSV at the SFJ be the source of?
primary or recurrent varicose veins
when doing varicose vein mapping, what is the patient position?
examined standing or with a large degree of head up tilt of examination table
why is the patient standing in varicose vein mapping?
ensures that adequate pressure will be exerted on the valves to test there incompetence, otherwise misleading measurement may be taken
is one or both legs examined in vein mapping?
both legs
where must patients put their weight when vein mapping?
weight must be places in the leg not being examined with slight flexion of the leg being examined
what is the most convenient method used to assess competence or incompetence of a venous segment?
squeeze the patients calf ot lower thigh to promote forward flow (augmentation)
what will incompetent valves allow?
reverse flow back through them after forward flow has ceased
what will competent valves show?
stop any reverse flow
what provides a more standardized stimulus than manual compresssion?
pressure cuffs being inflated and deflated rapidly
what may be done to induce reverse flow?
proximal compression (above the probe level)
what will valsalva manoever show?
incompetent segments
what are the disadvantages to induce reversal of flow?
1-the effect will only demonstrate reverse flow as far as the first competent valve so that any incompetant valves below this will not be demonstrated
2-patients do not always understant valsalva procedure and may not be consistent
when valsalva manover is not effective, what can be used to assess for reflux?
augmentation
when is augmentation useful?
popliteal vein and calf veins
what should happen when augmentation is done?
immediately after, the flow should return below the baseline
what does it mean when flow returns above the baseline?
indication there are incompetant valves below this level
what is reflux?
reverse flow occuring after the cessation of forward flow
when is reflux considered significant?
lasts more than 0.5 seconds
what may shorter periods of reversed flow represent?
the valve cusps coming together (slow closing valves)
what should reflux not be confused with?
reversal of flow which occurs with turbulence-this is seen on spectral doppler as reverse flow and forward flow occuring at the same time
color flow is used when the transducer is in what position?
TRV to asses cross section
what is required for examination protocol?
light probe pressure with a slight angle
what is done as the probe is slid cuadally?
valsalva manoever is in process
what can demonstrate reflux?
doppler spectrum
where does the exam begin?
in the groin
what vessels are examined and assessed?
CFV
SFJ
PFV
the patency and competence of the deep and superficial veins of thigh are assessed down to where?
level of the knee
what is suggestive of previous surgery with subsequent recanalization or collateral formation in the saphenous vein?
loss of normal smooth curve of the saphenous vein
what must be sought if the vein is incompetant below the SFJ?
presence of imcompetent perforatirs along the length of the LSV
where is the most comon location for an incompetant perfoating vein?
level of the junction of the mid and lower thirds of the thigh
where is the hunterian perforator?
mid thigh perforating vein (junction of the mid and lower thirds of the thigh)
what is the protocol when scanning the knee?
assess the popliteal vein and the sapheno-popliteal junction
what is difficult or impossible to induce in the calf vessels?
induce significant forward flow in the calf vessels as well as reflux
what is not reliable far from the abdomen?
valsalva manoever
what do we use in the thigh region?
proximal compression
look for ________ flow from the deep to superficial systems
outlfow
what is the direction of flow with superficial and deep veins?
superficial to deep
varcies should be traced proximally to identify what?
point of communication with deep or superficial segments
what we be careful not to compress?
superficial veins
why are perforator veins named that?
because they perforate the deep fascia of muscles, to connect the superfical veins to deep veins where they drain into
what is the role of perforator veins?
maintaing correct blood draining
why do perforator veins have valves?
prevent blood from flowing back (regurgitation) from deep to superficial veins in muscular sytole or contraction
where are most of the valves located?
exist along the length of the leg, greater in the calf than in the thigh
what are veins named after?
physicial who discovered them
where is Dodd’s perforator located?
inferior 1/3 of the thigh
where is Boyd’s perforator located?
at the knee level
where is Cockett’s perforator located?
at the inferior 2/3 of the leg
how many cocketts perforators are there?
3
- superior
- medium
- inferior
what is active venous reflux?
when the valves of perforator veins become incompetent they can cause venous reflux when the muscles contract
what can be responsible for the development of venous ulcers?
the resulting reflux can cause a rapid deterioration in an exisiting varicose disease
when are perforators considered diseased
perforators greater than 3mm in the calf and 4mm in the thigh
what is the preferred conduit for arterial bypass grafting in the coronary arteries and lower limb?
LSV
how can US assess the suitability of saphenous vein mapping?
measuring the caliber and available length
where is the measurment taken for saphenous vein mapping?
TRV
what is the ideal measurements in saphenous vein mapping?
ideally the vein should be more than 3-4mm wide and >2mm at the ankle if a long femoral-distal graft is considered
when may the LSV be removed?
removed for a coronary bypass or reversed lower limb arterial graft
what must be ruled out before removing the LSV?
thrombus
If an insitu lower limb arterial graft is to be performed, then perforating veins and superficial branches must have what done?
ligated to prevent an arteriovenous fistula from developing
when assessing the LSV, how is the exam preformed? (patient position)
with the patient standing to produce distension of the vein
why is the patient standing in the LSV exam?
allows easier location and better estimation of the caliber of the vessel
what is used to mark the skin along the course of the vein to locate perforators?
fiber tipped markers
where are markers made on the leg?
at the location of the vein at each end of the transducer length
once main marks have been made on the leg then what can be identified and marked?
location of the SFJ, dual segments and tributaries can be identified and marked
what orientation is used to identify veins?
TRV
what are the pitfalls to mapping scanning?
- patients may not beable to stand
- patient body habitus and tolerance for compression may be an issue
- bandages
- casts
- swelling
what position is used when examining the uper extremity?
with the bed flat and the patient in supine postition
what veins will collapse if the head is up?
jugular and subclavian veins
what is done after imaging with the head down (supine)?
the bed can be raised to allow for imaging of the arm veins
where is the arm positioned for examining the axillary veins?
repositioned and raised to allow access to the axilla
what do you do if the patient cannot lift their arm over their head?
patient may extend the arm out laterally with the elbow bend and hand near head
what is the postion of the arm when imaging the medial portion of the upper and lower arm?
lower position with arm externally rotated and palm faced upward
what jusgular vein so we image?
both internal and external jugular veins of the neck
where is the internal jugualr located?
followed in the lateral neck alongside the carotid artery
where is the external jugular vein located?
superficial and posterior to the internal jugular-light probe pressure needed
what is important if compression is difficult?
color flow
why is following the brachiocephalic (innominate) difficult?
because of the sternum and air-filled lungs that block ultrasound
what can be used to image the innominate?
small footprint probes that operate at low frequencies
what is the normal flow in the innominate?
pulsatile phasic flow is normal due to proximmity to the heart
what does the subclavian vein pass under?
the clavicle
what is one way to check for check for collapsibity of the subclavian vein?
patient take a quick breath in with pursed lips, which allows the vein to collapse while doppler is on
what will happen in spectral with breathing in when looking at the subclavian?
spike like augmentation
what does a non phasic flow pattern idicate when looking at the subclavin?
more proximal obstruction
what indicated a central venous stenosis or occlusion in the subclavian during deep inspiration?
ansence or diminshed subclavian vein flow or change in flow
where does the cephalic vein empty?
into the subclavian vein
where does the cephalic vein run?
runs across the shoulder and down the anterior-lateral border of the biceps muscle
what connects the cephalic to the basilic vein?
median cubital vein
-at the level of the anticubital fossa
how many braches are there for the cephalic vein?
2 branches in the forarm
where do the 2 branches of the cephalic vien travel?
down the volar (palmar) aspect of the forearm to the wrist while the other will roll onto the dorsal aspect of the forearm as it approaches the wrist
where does the subclavian vein become the axilary vein?
below the level where the subclavian V recieves the cephalic vein
is the axillary vein compressible?
yes and augmentable
how many brachial veins are there?
2, travel on either side of the brachial artery
are the superficial veins in the arm bigger or smaller than the deep?
superficial appear larger
where do the brachial veins form a short single vein?
at the antecubital fossa
where do the radial veins course along?
the volar aspect of the forearm on the radial side towards the thumb (lateral)
whta type of probe is needed for radial veins?
high resolution
where do the ulnar veins travel?
from the level of the brachial vein, the ulnar veins travel along the volar aspect of the forearm and enter the hand at the wrist on the ulnar side (medial)
where do we begin to find the basilic vein?
we go back to the midportion of the upper arm and find its distal end from the axillary vein
does the brachial or basilic vein appear larger?
brachail vein will appear larger
what does the basilic vein join?
at the anticubital fossa it joins with the median cubital vein
where does the median cubital vein pass?
crosses over the top of the brachial artery and vein like a freeway overpass to eventually connect to the cephalic vein
for a liver transplant, what are the anastomoses?
- suprahepatic vena cava
- infrahepatic vena cava
- hepatic arterty
- portal vein
- biliary duct
how is each anastomosis assessed?
grayscale and spectral doppler
what do anastomic regions have a higher chance of developing?
a stenosis or occlusion
what are the sequelae of events for an anastomosis?
- necrosis
- fibrosis
- stenosis
what should be interogated with the portal vein in a liver transplant?
all branches of portal vein
what is the most significant vascular complication (high mortality rate)?
hepatic artery thrombosis
how often does hepatic artery stenosis happen?
11%
how often does portal vein complications occur?
1-13%-narrowing of lumen at anastomotic site
how often IVC complications occur?
stenosis is a rarity-recurrent HCC may cause tumor in hepatic veins/IVC
what vascular patency must be assessed for transplanted vessels?
- hepatic artery
- portal vein
- IVC
- hepatic veins
what is inspected in vascular patency?
- narrowed diamter
- thrombus
- normal spectral waveform
when does renal artery stenosis occur in renal transplant?
months to years later
when does renal artery occlusion occur in a renal transplant?
first few days
where does a primary renal vein thrombos originate?
RV
where does seconday renal vein thrombosis extend?
into the iliac V
what anastomoses must be assessed?
- illiac A and V prior to the anastomosis
- RV and RV at the iliac anastomosis
- color image of both vessels long axis to show patency
- intrarenal RI-arcuate or interlobular
where is prone to stenosis in renal artery (native)?
main right renal artery at the ostium (takeoff from aorta)
why is the ostium of renal artery more prone to stenosis?
due to its sharp angle superiorly and then inferiorly toward the right kidney
what is a good indicator of renal disease?
a ratio between the RA stenosis flow and prox Ao flow
do we open or close the gate when imaging the ratio in the renals?
open the gate
what ratio in the renals show that it is NOT hemodynamically significant?
RA PSV/AO PSV <3.5
what is the waveform for a renal artery?
- low resistant
- distal RA-usually no window is seen
- PSV of up to 180cm/s is considered normal
what do low resistant waveforms demonstrate?
broad systolic peaks and forward flow throughout diastole
what are other low resistant renal artery examples?
- celiac
- hepatic
- splenic
- renal arteries
what is resistant index also known as?
pourcelot index
define resiatnt index?
index of pulseatility and opposition of flow
is angle correct used for RI?
no as it is angle dependant
what is the RI formula?
RI=PSV-EDV/PSV
where do we obtain a signal in the arcuate or segmental arteries?
Up, mid, and LP cortex
in the arcuate arteries, what RI indicates resistamce to flow due to main RA stenosis?
RI >0.7
what do high resistance waveforms demonstrate?
tall, narrow, sharp systolic peaks and reversed or absent flow
what are other examples of high resistant waveforms?
- infrarenal aorta, iliacs and fasting SMA
- due to many small branches encouteres
why does the SMA go to low resistant post prandial?
due to capillaries allowing for nutrients to pass into tissues
what controlls resistance?
capillaries
what will increase post prandially in the Celiac Axis?
PSV and diastolic flow
when will the main portal vein increase diameter?
after a meal
what will happen to the main portal vein during inspiration and expiration?
decrease with inspiration and increase with expiration due to the increased and decreased abdominal pressure respectively
when does the splenic vein diameter increase?
with portal hypertension
what does teh splenic vein drain?
spleen, pancreas, and portion of the stomach
what is the waveform of the SMV?
spontaneous phasic flow toward the liver
what is the normal measurement of thr SMV?
<10mm
when will the SMV increase in size?
- inspiration
- following a meal
- portal hypertension
what does the SMV drain?
- small intestines
- ascending
- transverse colon
what waveform does the hepatic artery demonstrate?
-low resistant waveform with continuous flow through diastole
when does teh hepatic artery increase flow velocity?
- jaundice
- cirrhosis
- lymphoma
- metastases
what is the normal hepatic artery PSV and EDV is a fasting patient?
30-40 cm/s
10-15 cm/s
what does the splenic artery give rise to?
gastroepiploic artery and branches to the pancreas and stomch
what may happen to the splenic artery with a pseudocyst?
may have a pseudoanuerysm
what causes IVC occlusion?
- extrinsic compression-nodes
- renal cell carcinoma
- hepatocellular carcinoma
what is a sign of IVC occlusion?
bilateral leg swelling
what can right heart failure lead to?
overdistension of IVC and hepatic veins and they appear larger
what does the right heart failure look like?
- normally phasic flow due to respiratory movements are absent
- IVC will measure almost the same in AP during expiration and inspiration
- vessels will appear larger
what is Budd Chiari Syndrome?
thrombus or hepatoma extension into hepatic veins
what is usually an underlying disease?
renal vein thrombosis
what happens with renal vein thrombosis?
- dehydration
- hypercoagubility
what does renal vein thrombosis look like?
- tumors of left kidney and adrenals grow into veins
- extrinsic compression-tumor, fibrosis, trauma
- large edematous kidney evident
