Chapter 29: Intraoperative Duplex Ultrasound Flashcards
self-produced, or from the same organism. In the case of bypass, using the patient’s own tissue
autologous/autogenous
Removal of plaque intima and part of the media of an artery to restore normal flow through the diseased segment
endarterectomy
Below the inguinal level. In the case of bypass, procedures from the groin down. (Outflow procedures)
infrainguinal
A device replacing an absent or damaged part. In the case of bypass, procedures done using a man-made tube.
prosthetic
Restoration of blood flow to an organ or area by way of bypass, endarterectomy, or angioplasty and stening.
revascularization
means by which a surgical field is isolated from nonsterile or contaminated materials
sterile technique
keeping a watch over. In the case of revascularization, it suggests periodically monitoring patency and functioning by some means.
surveillance
pertaining to the viscera; in this case, kidneys or intestines
visceral
anatomy examined during carotid endarterectomy
CCA
ICA
ECA
potential complications of carotid endarterectomy
intimal flap
residual plaque
platelet aggregate
suture line abnormalities
dissection
anatomy examined during infrainguinal revascularization
inflow artery
outflow artery
anastamotic regions
entire conduit
potential complications of infrainguinal revascularization
retained valves
AV fistulae
platelet aggregate
anastamotic or suture line abnormalities
Anatomy examined during renal and mesenteric artery bypass
anastamotic regions
renal artery
celiac artery
mesenteric artery
Potential complications of renal and mesenteric artery bypass
residual plaque
platelet aggregate
dissection
anastamotic or suture line abnormalities
hyperechoic plaque projecting into the vessel lumen; may display an abrupt edge
“shelf” lesion/residual lesion
small projection into vessel lumen usually less than 1 cm; disturbed flow or aliasing may be present
intimal flap
linear object seen extending for several centimeters, parallel to vessel walls; turbulent or disturbed flow present
dissection
hypoechoic or anechoic material adjacent to vessel wall; focal elevation in PSV, Increaesed velocity ratio
platelet aggregate
Stenosis: carotid or lower extremity bypass graft
PSV > 180cm/s
Velocity ration >2.5
Stenosis: renal or celiac artery
PSV >200 cm/s
Stenosis: superior mesenteric artery
PSV >250 cm/s
patent branch may be seen arising from an in situ bypass graft; turbulence and aliasing present in area of side branch; elevated diastolic velocities in bypass graft proximal to side branch
arteriovenous fistula
hyperechoic structure protruding into lumen of vein bypass graft; may be associated with slight dilation of valve sinus; turbulence of aliasing may be present
retained valve
turbulence or aliasing may be present; kink or wall irregularity may be present
suture line/ anastomotic problem
Injection of ______ during an infraguinal bypass can minimise the effects of vasospasm
papaverine
One of the most frequent operations performed by vascular surgeons
carotid endarterectomy
After a carotid endarterectomy the stroke rates drop below __%
3
most commonly used assessment during carotid endarterectomy
continuous-wave Doppler interrogation
plaque remaining in proximal CCA or distal ICA that appears as an abrupt edge or outcropping
shelf lesion
If a shelf lesion is more than __ mm thick, revision should occur
2
moving plaque within the bloodstream
residual plaque
If residual plaque is seen following a carotid endarterectomy, what is the next step
prompt revision
If an intimal flap is above __ mm, a revision is needed.
2
Result of vascular clamp injury; most common technical defects involve ECA
dissection
If the PSV of the ICA exceeds ___ cm/s or the ICA to CCA PSV ratio is greater than ______ cm
> 180 cm/s
2.5
Infrainguinal revascularization is performed for:
claudication
cranial limb ischemia
Infrainguinal revascularization is performed via:
percutaneous endovascular means
open surgical bypass using with autogenous (vein) or a prosthetic material
The choice of an appropriate conduit depends on:
level of bypass
available autogenous material
The _____ approach is more prone to abnormalities
autologous
Methods of assessing bypasses
palpation
continuous wave Doppler
angiography
angioscopy
duplex ultrasound scanning
What was the gold standard for infrainguinal revascularization?
arteriography
drawbacks of arteriography
inability to assess inflow
difficulty in visualizing the entire length of conduit
lack of physiological information provided
Findings that prompt revision in infrainguinal revascularization
PSV greater than 180 cm/s
velocity ratio greater than 2.5
may form at site of vessel wall injury
platelet aggregate
may be identified with in situ grafts; turbulent flow present in region of fistula with elevated diastolic flow velocities proximal to fistula
arteriovenous fistula
A velocity of more than ___ cm/s in a renal bypass is indicative of revision
200
Normal celiac artery PSV
less than 200 cm/s
Normal superior mesenteric artery PSV
less than 275 cm/s
Which of the following is considered the “gold standard” for intraoperative assessment of any type of revascularization?
a. duplex ultrasound
b. arteriography
c. CW Doppler only
d. palpation
a
Which duplex ultrasound system requirements would be best suited for intraoperative assessment?
a. portable systems with high-frequency transducers
b. high end systems with large array transducers
c. grayscale only systems with high frequency transducers
d. large systems with a variety of transducers
d
What is the primary role of the vascular technologist during intraoperative procedures?
operation of the ultrasound system as the vascular surgeon manipulates the transducer
In general, when performing an intraoperative assessment, which of the following imaging techniques is best?
a. grayscale imaging only
b. spectral Doppler analysis only
c. combination of grayscale, color, and spectral Doppler
d. color Doppler assessment only
c
What is NOT a benefit of angiography in the intraoperative assessment of carotid endarterectomy?
a. ability to visualize the intracranial carotid artery
b. ability to visualize the extracranial internal carotid artery
c. the use of contrast is not needed
d. It offers physiologic data as well as anatomic data
c
During intraoperative assessment of carotid endarterectomy, spectral Doppler demonstrated velocities of 200 cm/s in the internal carotid artery, whereas velocities in the common carotid artery were 70 cm/s. Based on these findings, which of the following is likely to occur?
a. closure of the surgical site with no further investigation
b. closure of the surgical site with duplex assessment performed 1 day postoperatively
c. repeat intraoperative duplex assessment 30 minutes later
d. revision of the surgical site with repeat duplex assessment after revision
d
Which of the following duplex ultrasound findings is NOT associated with platelet aggregation?
a. hypoechoic or anechoic material adjacent to vessel wall
b. focal elevation in peak systolic velocities
c. increased velocity ratios
d. linear object visualized parallel to vessel walls
d
Upon duplex assessment of a carotid endarterectomy site, shadowing is noted in the proximal internal carotid artery. What is the most likely cause of this shadowing?
artifact from the prosthetic patch at the endarterectomy site
Which of the following can lead to complications or failure of an infrainguinal bypass graft?
a. inadequate arterial flow
b. use of prosthetic material below the knee
c. significant disease in the outflow vessels
d. all of the above
d
Which of the following is a main advantage of intraoperative duplex assessment of infrainguinal bypass grafts?
a. complete anatomic evaluation of the graft
b. identification of retained valves
c. physiologic information is gathered as well as anatomic
d. shadowing caused by prosthetic material will enhance the image
b
What is the preferred bypass conduit for infrainguinal revascularization?
a. Dacron material
b. PTFE material
c. autologous material
d. all materials are equally preferred
d
What may abnormally low graft velocities in an infrainguinal bypass graft indicate?
poor outflow vessels
Which criterion is used most often when assessing whether to revise an infrainguinal bypass graft during intraoperative assessment?
PSV greater than 180 cm/s and velocity ratio greater than 2.5
During intraoperative duplex assessment of a lower extremity bypass graft, turbulent flow is noted in the mid-thigh with elevated diastolic flow in the proximal thigh. What are these findings consistent with?
arteriovenous fistula
Why may intraoperative duplex assessment of renal artery bypass be preferred over angiography?
Duplex ultrasound avoids the use of contrast in a renal compromised patient
Why is intraoperative duplex ultrasound NOT used in aortoiliac reconstruction?
small defects are not as patency-threatening in these large vessels
What velocity is typically used as an indication to revise a renal artery bypass during intraoperative assessment?
200 cm/s
During a superior mesenteric artery bypass intraoperative evaluation, an intimal flap is discovered and velocities were 300 cm/s. What would likely occur with this graft?
graft failure is imminent even with intervention
What is a common venous procedure in which intraoperative monitoring is routinely used?
endovenous laser therapy
What is an evolving ultrasound technology used for guidance of endovenous interventions?
IVUS
A typical transducer used during an intraoperative procedure would be a(n) _____ frequency, linear arry.
multi
During an intraoperative procedure, a sterile _____ is placed over the transducer once filled with sterile gel, and bubbles are removed to reduce interference.
sheath
In duplex assessment of intrainguinal revascularization, injection of papaverine into the bypass is helpful in minimizing the effects of ______
vasospasm
Because prosthetic materials absorb _____, intraoperative scanning of these materials is virtually impossible, however, prosthetic _____ in carotid endarterectomy can usually be worked around.
air
patch
For the vascular technologist to assist in the operating room, they must have familiarity with ____ technique.
sterile
Carotid endarterectomy is one of the most common operations performed by vascular surgeons and typically has stroke rates below ____%, however, there remains some value of intraoperative assessment to minimize residual ____.
3
residual
Continuous-wave Doppler is probably the most commonly used assessment during cartoid endarterectomy; however, _____ wave Doppler or _____ imaging is being shown to be effective for intraoperative assessment.
pulsed
B-mode
During duplex assessment of carotid endarterectomy, velocities are obtained from all the carotid arteries, and B-mode images are closely examined for wall ______
irregularities
Plaque remaining in the proximal internal carotid artery or distal common carotid artery after endarterectomy, which appears as an abrupt edge or outcropping, is oftern referred to as a(n) ______
shelf lesion
A(n) ______ is another complication of endarterectomy and is often revised if in excess of ___ mm.
intimal flap
2
Infrainguinal revascularization can be performed for claudication or _______
critical limb ischemia
While carotid endarterectomy is fairly standardized, issues are common with infrainguinal revascularization because there are many _____ in the performance of the procedure
variations
The so-called “_____” veins are more prone to abnormalities that can result in failure of an infrainguinal bypass graft
alternative
To identify retained valves, scarred areas, arteriovenous fistula, or platelet aggregation, duplex scanning during lower extremity bypass allows the ______ of the bypass to be evaluated.
entire length
Findings the prompt revision of lower extremity bypass grafts include a peak systolic velocity greater than ____ cm/s and a velocity greater than ____.
180
2.5
On duplex assessment of infrainguinal bypass, an increased velocity was noted; however, the lumen of the conduit appears anechoic– this could be the result of ______
platelet aggregation
Duplex sonography has distinct advantages over angiography in the assessment of visceral revascularization, including the ability to visualize small vessels and the lack of the need for _____, particularly for patients with poor renal function./
contrast
In renal bypass assessment, velocities of ____ cm/s by duplex scanning were an indication for revision.
200
Abnormal intraoperative duplex studies of mesenteric bypass grafts have been associated with early _____, graft ____, and even death
reintervention
failure
Criteria for normal results of a mesenteric bypass graft include peak systolic velocities below ___ cm/s for the celiac artery and _____ cm/s for the superior mesenteric artery, a velocity ratio less than ____ and no technical defects
200
275
2.0
