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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3742_Библиотеки_им_академика_М_И_Перельмана
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10 Section 1: Anatomy, Physiology, and Hemodynamics
C
VPV
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transperitoneal repair of the juxtarenal abdominal aortic aneurysm. Mobilization of the left
renal vein and placement of a silastic vessel loop around the left renal vein may provide adequate
exposure for suprarenal artery clamping. It is important to decide which technique (mobilization
or division) to use because preservation of these branches is critical to provide collateral venous
outflow if the left renal vein needs to be ligated. The 5-year survival after open juxtarenal abdominal aortic aneurysm repair is 70%, even at centers of excellence with low perioperative mortality.
Correct Answer A Right crus
Reference
Shepard, A. D. (2017). Open nonruptured infrarenal aortic aneurysm repair. In S. S. Hans,
A. D. Shepard, & H. R. Weaver (Eds.), Endovascular and open vascular reconstructions: a practical
approach (pp. 197–204). Boca Raton, FL: CRC Press.
17. RATIONALE
Vascular compliance and stiffness of the arterial wall influence the pulsatility of the pressure
waveforms. Stiffness (E) is the ratio between increments in stress and strain. Vascular stiffness
(E) is determined by the ratio of elastin to collagen fibers, with more collagen resulting in a
thicker wall, which results in stiffer vessels. Vascular stiffness is a metric of vascular health, as
it plays an important role in dampening the pulse of pressure as it propagates from the arterial
tree. Compliance (C) is the change in volume (ΔV) imposed on the vessel by a given change in
pressure (ΔP), such as the pulse pressure (PP) between the systole and diastole.
=
=
The compliance of an artery depends on the pressure that it endures. The larger the pressure,
the smaller the compliance. Distensibility (D) refers to the ratio of changes in the luminal area
between systole and diastole divided by the pulse pressure. Viscosity is an important contributor to resistance. In fluids like plasma, the viscosity is constant, but whole blood has a complex
viscosity pattern due to the mixture of plasma, cells, and proteins. Hematocrit levels have a
profound effect on blood viscosity, with higher hematocrit greatly increasing the viscosity for all
shear rates.
Correct Answer C More collagen and a thicker wall
Section 1: Anatomy, Physiology, and Hemodynamics 11
Reference
Xiao, N., Humphrey, J. D., & Figueroa, C. A. (2013). Multi-scale computational model of three-
dimensional hemodynamics within a deformable full-body arterial network. J Comput Phys,
244, 22–40. PMID: 23729840.
18. RATIONALE
Flow in a liquid pipeline (blood vessels in most instances) may be a smooth, laminar flow, also
known as viscous flow. A visualization of laminar flow can be seen in the figure. Delaminar
flow is characterized by a gradient of flow lines representing different blood velocities at different locations in a tube (blood vessels). These differences in blood flow velocities are due to shear
stress. Because of friction, there is a decrease in the velocity of the blood closest to the wall. As
the liquid (blood) flow rate is increased, the blood velocity increases, and the flow will change
from laminar to turbulent flow with eddies. The Reynolds number is a value for a given f luid
(blood), the conditions at which flow will remain laminar. Blood viscosity (cells and protein) is a
variable affecting the Reynolds number. Laminar flow ceases when Reynolds number is greater
than 2000.
Correct Answer D Greater than 2000
Reference
Falkovich, G. (2018). Basic notations and steady flows. In G. Falkovich (Ed.), Fluid mechanics (2nd ed.,
pp. 1–62). United Kingdom: Cambridge University Press.
MCQs 1–27
SECTION 2: VASCULAR LABORATORY
Q1. The ideal angle of insonation when inter-
rogating the carotid artery during carotid
duplex imaging is:
A. 30 degrees
B. 45 degrees
C. 60 degrees
D. 90 degrees
Q2. Echogenicity on a B-mode imaging is
based on a comparison with a reference
structure of a plaque. Select the appropriate combination for comparison:
A. Blood for hyperechoic
B. Bone for hypoechoic
C. Strap muscles for hypoechoic
D. Sternocleidomastoid muscles for isoechoic
Q3. The following flow pattern is identified in
subclavian steal syndrome:
A. Reversal of flow in the ipsilateral carotid
artery
B. Reversal of flow in the ipsilateral verte-
bral artery
C. Reversal of flow in the internal mammary
artery
D. Reversal of flow in the subclavian artery
Q4. Transcranial Doppler evaluation is tech-
nically not feasible in:
A. Less than 5% of patients
B. 5%–15% of patients
C. 20%–30% of patients
D. Can be performed in all patients
Q5. A toe-brachial index is considered abnor-
mal when the value is:
A. 0.9
B. 0.8
C. 0.7
D. 0.63 or less
Q6. Aliasing with carotid color duplex exami-
nation is most likely to occur with all of
the following except:
A. Tortuous vessels
B. Low PRF settings
C. High PRF settings
D. Severe (hemodynamically significant)
carotid stenosis
Q7. A 64-year-old man has classic symp-
toms of left hip claudication on walking
100 yards with the relief of the pain at
rest. Peripheral pulses in the right lower
extremity are normal. In the left lower
extremity, pulses are slightly diminished
but palpable. Ankle-brachial index is 1.0
on both sides. There is no history of back
pain, and neurogenic claudication is ruled
out by normal MRI of the lumbar spine.
The next course of action is:
A. CTA of abdomen and lower extremities
B. MRA of abdomen and lower extremities
C. Exercise testing
D. Catheter-based lower extremity
arteriography
DOI: 10.1201/9781003389897-2
Section 2: Vascular Laboratory 13
Q8. Flow signal is least dependent on Doppler
angle with:
A. Gray-scale imaging
B. Color Doppler imaging
C. Power Doppler imaging
D. Pulsed Doppler spectral analysis
Q9. The limitations of carotid duplex
examination include all of the following
except:
A. Excessive carotid plaque calcification
B. Contralateral carotid occlusion
C. Excessive tortuosity or looping of ICA
D. Detection of intimal flap
Q10. The main advantage of MR angiography is:
A. Lower cost compared to other imaging
modalities
B. Use of contrast medium is not necessary
C. Greater exposure to ionizing radiation
D. Better resolution than catheter-based
arteriography
Q11. Multidetector CTA for cerebrovascular
imaging is superior to MRA, as it is faster,
easier to acquire, and less expensive than
MRA. In terms of resolution, CTA has:
A. Same resolution as MRA
B. Better resolution than MRA
C. Inferior resolution than MRA
D. Less radiation
Q12. The best imaging technique for evaluation
of the vertebral arteries is:
A. DSA
B. Duplex ultrasound
C. MRA
D. CTA
Q13. How does lower extremity CT angi-
ography compare to catheter-based
angiography?
A. Less contrast and lower radiation
exposure
B. Less contrast but more radiation
exposure
C. More contrast and more radiation
exposure
D. More contrast and lower radiation
exposure
Q14. A 60-year-old man has typical symptoms
of bilateral hip claudication. His baseline
ankle-brachial index (ABI) at rest is 0.98 on
the right and 0.97 on the left. Post-exercise
on a treadmill, ABI drops to 0.78 on the right
and 0.72 on the left, with a return to baseline values after 15 minutes. What level of
disease is most likely present in this patient?
A. Multilevel
B. Iliac artery occlusive disease
C. Femoral-popliteal occlusive disease
D. Neurogenic claudication
Q15. A dampened waveform with a delay to
peak systole is seen in the common femoral
artery. This type of pattern is seen in which
of the follow ing vascular pathologies?
A. Pseudoaneurysm
B. Distal occlusion
C. Aortoiliac occlusive disease
D. Arterial venous fistula
Q16. Which statement best ref lects a hemody-
namically significant stenosis in an artery?
A. An increase in the velocity at the site of
stenosis
B. A decrease in the velocity at the site of
stenosis
C. Increased pressure gradient across the
stenotic segment
D. An increase in the velocity at the site of
stenosis and increased pressure gradient
across the stenotic segment
Q17. Volume flow in a brachiocephalic arterio-
venous fistula for hemodialysis access is:
A. 500–600 mL/min
B. 601–700 mL/min
C. 701–800 mL/min
D. Greater than 800 mL/min
Q18. Plethysmography pulse-volume record-
ings are preferable to Doppler segmental
pressures in patients with suspected lower
extremity arterial occlusive disease in:
A. Type II diabetes mellitus
B. Peripheral neuropathy
C. Calcified arteries
D. Cases where the specific type or location
of the lesion needs to be determined
14 Section 2: Vascular Laboratory
Q19. Flow reversal that is positive for superfi-
cial venous reflux is:
A. >0.05 second
B. >0.5 second
C. >0.005 second
D. >5 seconds
Q20. A phasic spectral waveform within the
right subclavian vein and a pulsatile
spectral Doppler waveform within the left
subclavian venous flow suggests:
A. An obstruction proximal to the left sub-
clavian vein
B. An obstruction proximal to the right sub-
clavian vein
C. An obstruction distal to the left subcla-
vian vein
D. An obstruction distal to the right subcla-
vian vein
Q21. A monophasic fasting superior mesenteric
artery signal is suggestive of which of the
following complications:
A. Median arcuate ligament syndrome
B. Superior mesenteric artery stenosis
C. Portal hypertension
D. A normal waveform
Q22. For diagnosis of significant renal artery
stenosis, an abnormal renal-to-aortic
ratio is:
A. <2
B. 2–2.5
C. 2.5–3.4
D. >3.5
Q23. During the duplex evaluation of the
femoral-popliteal in situ arterial bypass,
the velocity at the proximal anastomosis
is 80 cm/s. Doppler signal within 2 cm of
the distal anastomosis detects a velocity of
220 cm/s. These findings are indicative of:
A. <20% stenosis of the in situ bypass
B. Normal flow in the bypass
C. 20%–50% stenosis in the bypass
D. >50%–99% stenosis in the bypass
Q24. The cold water immersion test results in a
greater than 20% decrease in peak systolic
pressure, which is suggestive of:
A. Thoracic outlet syndrome
B. Primary Raynaud disease
C. Scleroderma with finger ulceration
D. Systemic lupus erythematosus
Q25. A 70-year-old woman underwent SMA
stenting and celiac artery stenting angioplasty for severe celiac artery stenosis and
>70% stenosis of the SMA for symptoms of
intestinal angina 5 years ago. On followup, peak systolic velocity (PSV) of the
SMA is 402 cm/s with symptoms of vague
abdominal discomfort. The PSV of the
celiac artery is 260 cm/s. These findings
suggest:
A. >70% in-stent restenosis (ISR) of the
celiac artery but <70% ISR of the SMA
B. >70% ISR of the SMA and <70% ISR of the
celiac artery
C. <70% ISR of the celiac artery and SMA
D. >70% ISR of celiac artery and SMA
Q26. A 76-year-old woman underwent carotid
stenting for symptomatic greater than
70% stenosis of the right internal carotid
artery. A follow-up carotid duplex at
2 years demonstrates a peak systolic
velocity of 346 cm/s and IC/CC ratio of
4.20. This is suggestive of what degree of
in-stent restenosis:
A. ICA occlusion
B. Equal to or greater than 80% reduction
C. Equal to or greater than 50% reduction
D. Equal to or greater than 20% reduction
Q27. The best noninvasive diagnostic imaging
study for the diagnosis of vertebral artery
dissection is:
A. Duplex ultrasonography
B. CTA
C. MRA
D. Catheter-based arteriography
Section 2: Vascular Laboratory 15
RATIONALE 1–27
1. RATIONALE
Carotid duplex scanning combines B-mode imaging, pulsed Doppler spectral analysis, and
color-flow imaging. B-mode imaging helps in the evaluation of the carotid plaque morphology according to its echogenicity, with hypoechoic-like soft plaques, hyperechoic-like
calcific plaques, or isoechoic. It can also determine if the plaque is homogeneous or heterogeneous. That may be attributed to intraplaque hemorrhage. Using B-mode imaging as a
guide to the precise placement of the pulse Doppler gate velocity measurements and spectral
sound analysis of the Doppler signals can be used to determine the degree of stenosis. An
angle of 60 degrees between the axis of the artery and the sample volume should be maintained for velocity measurements. In patients with severe angulation or tortuosity, an angle
of less than 60 degrees should be used. An angle greater than 60 degrees should never be
used, as small errors in angle measurements will cause large errors in the calculation of
velocity measurements.
Correct Answer C 60 degrees
Reference
Gaiser, R., & Fox, T. B. (2016). Vascular technology examination PREP (1st ed.). New York:
McGraw Hill.
2. RATIONALE
Echogenicity ref lects the overall brightness of the plaque, with hyperechoic referring to echogenic (white) and hypoechoic referring to echolucent (dark or black) plaques. The reference
structure to which echogenicity of the plaque should be compared is the blood for hypoechoic
and bone for hyperechoic. Complicated carotid plaques that are more often associated with
ipsilateral focal neurological symptoms are commonly echolucent and heterogenous with an
irregular ulcerated surface in contrast to uncomplicated plaques often seen in asymptomatic
patients that are usually hyperechoic homogeneous with a smooth surface. The reference structure for isoechoic plaque is the sternomastoid muscle.
Correct Answer D Sternocleidomastoid muscles for isoechoic
Reference
Kremkau, F. W. (2020). Principles and instruments of ultrasonography. In J. S. Pellerito & J. D. Pollack
(Eds.), Introduction to vascular sonography (pp. 23–55). Philadelphia, PA: Elsevier.
3. RATIONALE
Normally, the flow in the vertebral artery is toward the cranium. Demonstration of absent
flow indicates occlusion. In patients with asymmetric flow in both vertebral arteries with
symptoms of ischemia, upper extremity arterial Doppler is used to determine the difference
between blood pressure in both arms. In most instances, subclavian steal syndrome is a
hemodynamic entity. The so-called alternating flow (bunny rabbit) or total reversal of flow at
rest demonstrates the stages of subclavian steal. It is called a syndrome if clinical symptoms
of posterior ischemia develop.
16 Section 2: Vascular Laboratory
Spect ral Doppler show ing a “bunny rabbit” waveform indicating latent or occult subclav ian stenosis.
Correct Answer B Reversal of flow in the ipsilateral vertebral artery
Reference
Kha n, S., Rich, P., Clifton, A., & Markus, H. S. (2009). Noninvasive detection of vertebral artery stenosis:
a comparison of contrast-enhanced MR angiography, CT angiography, and ultrasound. Stroke,
40(11), 3499–3503. PMID: 19762707
4. RATIONALE
Transcranial Doppler is helpful in evaluating blood flow in the circle of Willis in the brain
through an intact skull. A 2-MHz pulsed Doppler is used to evaluate the intracranial MCA, ACA,
PCA, and distal ICA, as well as the ophthalmic, vertebral, and basilar arteries through transtemporal, transorbital, submandibular, and transforaminal windows in the skull. The temporal windows needed for evaluation are absent in 5%–15% of patients. The machine emits the
sound pulse and waits for the time needed to make a round trip to and from the specific depth
and then senses the reflected signal so that the direction of flow, pulsatility index, and velocity based on Doppler pulsatility can be determined. Each intracranial vessel can be insonated
through a specific bone window and at a specific depth. Typically, the MCA is insonated
through a temporal window at a depth of 30–60 mm with a flow toward the probe and a mean
velocity of 55 ± 12 cm per second. Diagnosis of intracranial stenosis and occlusion is based on
an increase in the velocity, post-stenotic turbulence, discrepancy between the two sides, and
reversal of flow.
Section 2: Vascular Laboratory 17
Left middle cerebral arter y (MCA) stenosis showing elevated velocity in t he left MCA as well as post-stenotic turbulence.
Correct Answer B 5%–15% of patients
Reference
Ribo, M., & Alexandrov, A. (2007). Vertebral artery ultrasonography. In A. F. AbuRahma & J. J. Bergan
(Eds.), Noninvasive vascular diagnosis: a practical guide to therapy (pp. 97–102). London:
Springer-Verlag.
5. RATIONALE
A normal ankle-brachial index is 0.93–1.3, mild disease equals 0.8–0.9, moderate disease equals
0.4–0.8, and severe disease is less than 0.4. For the toe-brachial index, normal is equal to or greater
than 0.63, mild disease is 0.4–0.62, moderate disease is 0.20–0.39, and severe disease is 0.19.
Ankle-Brachial Index Toe-Brachial Index
Normal 0.93–1.3
Normal ≥0.63
Mild 0.8–0.92 Mild 0.4–0.62
Moderate 0.4–0.8 Moderate 0.20–0.39
Severe <0.4
Severe 0.19
Toe pressure measurement is performed in a similar fashion as arm and ankle pressure measurements. A mini cuff is placed around the base of the digit (commonly the first digit, but occasionally the second) and attached to the standard monometer. The most commonly used probes
are photoplethysmography (PPG) probes and continuous-wave Doppler flow detectors placed
on the distal phalanx. In patients with diabetes mellitus and chronic kidney disease, the tibial
arteries are incompressible due to calcification and the ankle-brachial index is not obtainable.
Toe pressures are sensitive to a decrease in arterial flow to the plantar arch and digital arteries.
18 Section 2: Vascular Laboratory
In patients with calcification and non-compressibility of the digital arteries, transcutaneous oxygen measurements are more useful. Toe pressure and toe-brachial index are predictive of cardiovascular mortality and amputation-free survival in patients with peripheral arterial disease.
Correct Answer D 0.63 or less
Reference
Rooke, T. W., Hirsch, A. T., & Misra, S., et al. (2012). 2011 ACCF/AHA focused update of the guideline for
the management of patients with peripheral artery disease (updating the 2005 guideline): a report
of the American College of Cardiology Foundation/American Heart Association Task Force on
Practice Guidelines: developed in collaboration with the Society for Cardiovascular Angiography
and Interventions, Society of Interventional Radiology, Society for Vascular Medicine, and Society
for Vascular Surgery. Catheter Cardiovasc Interv, 79(4), 501–531. PMID: 21960485
6. RATIONALE
Pulsed-wave spectral Doppler sends a pulse, and the machine waits until the return of that
pulse before the next pulse is sent. Pulse repetition frequency (PRF) is the number of pulses
transmitted in 1 second. Aliasing is a wraparound of the spectral waveform as it is out of insufficient sampling speed. If a sampling speed is low, the displayed waveform is incorrect, causing
positive shift information to be displayed as negative. Aliasing is the result of the Doppler shift
exceeding one half the PRF (Nyquist limits). In order to eliminate aliasing, the frequency shift
needs to decrease and PRF needs to increase. Increasing the PRF can be achieved by increasing the Doppler PRF or decreasing the depth. The Doppler shift can be reduced by lowering the
operating frequency of the transducers. A tortuous ICA, significant ICA stenosis, and low PRF
have the potential to cause aliasing. Increasing the Doppler angle will also eliminate aliasing.
Color-flow and spectral Doppler image of the left internal carotid artery showing peak systolic velocities of 636 cm/s
and end-diastolic velocities of 182 cm/s consistent with a 70%–99% stenosis. The color image also shows color “aliasing”
indicating a high-grade lesion.
Section 2: Vascular Laboratory 19
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
Correct Answer C High PRF settings
Reference
Kremkau, F. W. (2020). Principles and instruments of ultrasonography. In J. S. Pellerito & J. D. Pollack
(Eds.), Introduction to vascular sonography (pp. 23–55). Philadelphia, PA: Elsevier.
7. RATIONALE
Most patients with symptoms of intermittent claudication have a decreased ankle-brachial
index (ABI) at rest. Exercise testing is performed in the select group of symptomatic patients
with normal ABI. After measurements of resting ABI, BP cuffs are kept at both ankles and upper
extremities and the patient walks on a treadmill 2 miles/hour at a 12-degree inclination for
5 minutes or the patient must stop because of pain. After resting, ankle and arm pressures are
measured every 2 minutes for 10 minutes. If there is no decrease in ABI or there is an absence
of symptoms, arterial occlusion can be ruled out. Patients with peripheral arterial disease but
normal ABI at rest experience a mild drop in ABI after exercise that returns to baseline within
minutes. Patients with moderate disease have a persistent decrease in ABI for 10–15 minutes
post-exercise. The exercise test is more helpful in the diagnosis of iliac artery as compared to
femoral artery occlusive disease. In patients who cannot tolerate walking on a treadmill, flow
can be increased by reactive hyperemia using torniquet occlusion of a proximal cuff above the
systolic blood pressure for 5 minutes.
Correct Answer C Exercise testing
Reference
Stivalet, O., Paisant, A., Belabbas, D., et al. (2019). Exercise testing criteria to diagnose lower extrem-
ity peripheral artery disease assessed by computed-tomography angiography. PLos One, 14(6),
e0219082. PMID: 31247050
8. RATIONALE
Arterial duplex test interpretation is based on both normal B-mode gray-scale imaging and
Doppler findings varying from normal to an increasing degree of stenosis. The velocity spectrum of the aorta, iliac, femoral-popliteal-tibial, and external carotid artery is triphasic with
high outflow resistance with a systolic flow component, early reversal of flow in diastole, and
a late diastolic forward flow. Low-resistance arterial flow as in renal, celiac, vertebral, and
the ICA is continuous throughout the pulse cycle with a systolic flow component resulting
in a monophasic pulsed Doppler signal. Color Doppler imaging refers to pixel encoding of
blood flow (away or toward the transducer) and mean velocity. When the blood flow velocity
is greater than the mean peak velocity, a threshold of the color bar (color aliasing) will occur
as the pulse repetition frequency is no longer sufficient. Increasing the Doppler angle and
pulse repetition frequency is used to reduce the aliasing artifact. Pulse Doppler imaging is
based on the amplitude of a backscattered Doppler signal. The sensitivity of the flow direction increases three to five times as compared to color Doppler imaging. This technique is
used for the evaluation of small-sized vessels and detection of slow or thicker flow associated
with high-grade stenosis. Flow direction cannot be determined with power Doppler imaging, and the flow signal is less dependent on the Doppler angle. B-flow imaging reveals blood
flow and a gray scale with different shades of gray and is most useful to demonstrate complex
flow abnormalities in the bypass graft anastomosis and AV fistulas, as Doppler artifacts can
obscure flow patterns.
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