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MCQs 1–5
SECTION 3: RADIATION SAFETY
Q1. The threshold effective single dose of
radiation resulting in dermal necrosis is:
A. 10 Sv
B. 11–19 Sv
C. 20–24 Sv
D. 25 Sv
Q2. A statistically significant increase in can-
cer risk has not been proven in populations exposed to doses of less than:
A. 100 mSv
B. 200 mSv
C. 300 mSv
D. 400 mSv
Q3. Per ICRP recommendations, the annual
whole-body dose limit for physicians in
1 year should not exceed:
A. 20 mSv
B. 30 mSv
C. 40 mSv
D. 50 mSv
Q4. The typical effective dose in computed
tomography of the abdomen is:
A. 5 mSv
B. 10 mSv
C. 20 mSv
D. 25 mSv
Q5. What amount of scattered radiation dose
will decrease if the square of the distance
of the operator doubles?
A. Twofold
B. Fourfold
C. Sixfold
D. Eightfold
DOI: 10.1201/9781003389897-3
Section 3: Radiation Safety 31
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RATIONALE 1–5
1. RATIONALE
The deterministic effects of radiation are dose dependent resulting in cell death; loss of hair follicles; and effects on the skin, bone marrow, gonads, and lens of the eye. These acute events take
place when the threshold level of radiation has been exceeded. The dose required to produce
these determinative effects often exceed 1–2 Sv. Symptoms develop when a significant proportion of cells are killed by radiation with a subsequent inflammatory response and eventual
fibrosis, resulting in further organ damage. The effective threshold of a single dose (Sv) resulting in temporary sterility is 0.1, permanent sterility is 3–6, cataracts is 0.5, bone marrow depression is 0.5, transient erythema of the skin is 2, desquamation is 2–10, temporary hair loss is 4,
dermal necrosis is 25, and skin atrophy is 10 (Sv).
Correct Answer D 25 Sv
Reference
National Research Council. (2006). Health risks from exposure to low levels of ionizing radiation: BEIR
VII phase 2. Washington, DC: National Academies Press.
2. RATIONALE
The stochastic effects of radiation cause cell mutations resulting from DNA damage to a single
cell and are unrelated to the dose. Mutations may lead to cancer and heritable genetic defects.
Radiation doses of less than 100 mSv/year in terms of stochastic effects is very low. Leukemia
and other cancers have been associated with radiation exposure. The probability of fatal cancer
developing as a result of radiation exposure is 4% per 1 Sv of a lifetime dose equivalent. Among
atomic bomb survivors, there is an increase in sickle cell leukemia, lung, thyroid, breast, skin,
and GI tract tumors. A statistically significant risk of cancer has not been demonstrated in populations exposed to doses of less than 100 mSv. The latent period of development of malignancy
following radiation exposure is 2–5 years for leukemia, 5 years for thyroid cancer, and
10 or more years for other cancers.
Correct Answer A 100 mSv
Reference
Laurier, D., Richardson, D. B., Cardis, E., et al. (2017). The international nuclear workers study
(in works): a collaborative epidemiological study to improve knowledge about health effects of
protracted low-dose exposure. Radiat Prot Dosimetry, 173(1–3), 21–25. PMID: 27885078
3. RATIONALE
The maximum permissible dose (MPD) is the upper limit of the allowed radiation dose that
one may receive without the attendant risk of significant side effects. The annual whole-body
dose limit for physicians is 50 mSv. The ICRP safety dose recommendations call for a wholebody effective dose limit of 20 mSv/1 year, average dose 5 years. For ocular lens, 20 mSv/yr;
skin, 500 mSv/yr; and extremities, 500 mSv/yr. The ICRP system of protection in medical
practice stresses the basic principles of justification, optimization dose, and risk limits. It is
the responsibility of the hospital and medical personnel to ensure that the radiation equipment is maintained (preventative maintenance) to deliver the lowest dose of radiation and
32 Section 3: Radiation Safety
to ensure the safety instructions and all productive measures are adopted by all involved
personnel. Hospitals have radiation physicists overseeing the radiation safety, and systems
of reporting and immediate measures are in place in situations where the recommended
dose limit is exceeded.
Correct Answer D 50 mSv
Reference
Rehani, M. M., Ciraj-Bjelac, O., Vañó, E., et al. (2010). ICRP Publication 117. Radiological protection
in fluoroscopically guided procedures performed outside the imaging department. Ann ICRP,
40(6), 1–102. PMID: 22732420
4. RATIONALE
Whenever possible, for diagnostic evaluations, MRI or ultrasound imaging should be considered, as there is no radiation involved with these two modalities. The effective dose of spiral and
multislice detector CT scans is 10%–30% higher than with past-generation CT scans. In order
to reduce radiation exposure to a CT scan following endovascular aneurysm repair (EVAR),
techniques such as automated tube current modulation or attenuation-based kilovoltage selection algorithms can be used. The effective dose of a CT scan of the abdomen and pelvis is in the
range of 10–20 mSv, and repeated CT exams following the EVAR effective dose may approach
harmful levels. The risk of development of solid organ malignancy from a postoperative CT scan
following EVAR is higher in women, young patients, and patients undergoing repeated scans.
Dyna CT (three-dimensional rotational angiography) results in a mean dose produced in the
range of 3500–4000 u Gym2, which is about 8 times a reduction in the radiation as compared to
standard multidetector CT.
Correct Answer B 10 mSv
Reference
Smith-Bindman, R., Lipson, J., Marcus, R., et al. (2009). Radiation dose associated with common com-
puted tomography examinations and the associated lifetime attributable risk of cancer. Arch
Intern Med, 169(22), 2078–2086. PMID: 20008690
5. RATIONALE
All personnel performing X-ray imaging studies should maintain the maximum distance
from the X-ray tube. The image intensifier should be kept as close to the patient and the
tube as far away as possible to reduce the dose to the patient’s skin. The amount of scattered
radiation decreases with the square of the distance to the tube. Exposure equals
1/d2. Therefore, the radiation dose will diminish fourfold if the distance from the operator
doubles. The left anterior oblique view exposes the operator extending on the right side of
the patient to the greatest amount of radiation, as the tube is closest to the operator. The
radiation dose is 3–5 times higher than the right anterior oblique view. Steep gantry angulations also increase radiation exposure. Use of ceiling-mounted plexiglass should be used
to decrease exposure from scattered radiation. Raising the fluoroscopic table and lowering
the imaging intensifier decreases radiation exposure. A 0.25-mm lead-equivalent apron,
lead glasses, and thyroid shields should always be worn. The front of the lead apron should
be kept away from the X-ray tube. Protective gloves (at least 0.35-mm lead equivalent) are
Section 3: Radiation Safety 33
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not often used due to reduced tactical sensitivity. Lead-equivalent surgical caps reduce the
exposure to the brain during interventions. Radiation safety training should be a component of every training program in surgery.
Correct Answer B Fourfold
Reference
Haqqani, O. P., Agarwal, P. K., Halin, N. M., & Iafrati, M. D. (2012). Minimizing radiation exposure to
the vascular surgeon. J Vasc Surg, 55(3), 799–805. PMID: 22079168
MCQs 1–14
SECTION 4: VASCULAR MEDICINE
Q1. Each of the following antiplatelet medica-
tions has been proven to reduce the risk of
stroke except:
A. Ticagrelor
B. Aspirin and dipyridamole
C. Clopidogrel
D. Aspirin
Q2. Which statin was the first to be shown to
reduce the risk of stroke in patients with
previous stroke and no history of coronary
artery disease?
A. Atorvastatin
B. Lovastatin
C. Simvastatin
D. Pravastatin
Q3. In the CREST-2 trial the target for lower-
ing LDL is:
A. <130 mg/dL
B. <100 mg/dL
C. <70 mg/dL
D. <50 mg/dL
Q4. A 65-year-old man is scheduled to
undergo percutaneous iliac stenting for a
common artery occlusion with symptoms
of disabling claudication. He is a known
former smoker (10 pack-years). He has a
history of well-controlled hypertension
and dyslipidemia. He denies symptoms of
chest pain or shortness of breath. The preintervention cardiac assessment should
include:
A. Nuclear cardiac stress test
B. CTA coronary arteries
C. 2D echocardiogram
D. Preintervention testing is not necessary
Q5. A 70-year-old woman is scheduled to
undergo open repair of a juxtarenal
abdominal aortic aneurysm. She quit
smoking 1 month ago and has a 50-packyear history of smoking. Which of
the following statements best reflects
her risk of developing pulmonary
complications?
A. Cessation of smoking 6 months prior to
the operation
B. Cessation of smoking 1 year prior to the
operation
C. Her risk of pulmonary complications
does not increase even if she does not
quit smoking prior to the operation
D. Cessation of smoking within 2 months of
the operation
Q6. A 50-year-old man with a history of
type I diabetes mellitus is scheduled
to undergo arteriography of the lower
extremities for ischemic gangrene of
the right big toe. Serum creatinine is
1.5 mm/dL (eGFR 40 mL). The best
strategy for the prevention of contrastinduced nephropathy is:
A. Administration of dopamine
B. Preprocedure hydration with normal
saline
C. Preprocedure hydration with normal
saline for 12 hours followed by postprocedure hydration with normal saline,
reducing the volume of the contrast and
use of diluted contrast and using CO
angiography whenever feasible
D. Obtain MRA of the lower extremities
instead of catheter-based arteriography
2
DOI: 10.1201/9781003389897-4
Section 4: Vascular Medicine 35
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Q7. A 62-year-old man had a femoral-tibial
bypass for critical limb ischemia 3 days
ago. His postoperative course is uncomplicated. His hemoglobin on postoperative
day 3 is 7.4 gm/dL. The transfusion trigger
in this patient is:
A. Hemoglobin less than 10 gm/dL
B. Hemoglobin less than 9 gm/dL
C. Hemoglobin less than 8 gm/dL
D. Hemoglobin less than 7 gm/dL
Q8. A 66-year-old man on apixaban for atrial
fibrillation presents with a ruptured
juxtarenal aortic aneurysm not suitable
for endovascular repair. The most suitable
agent to reverse the action of apixaban is:
A. Fresh-frozen plasma
B. Idarucizumab
C. Recombinant factor XA (Andexxa)
D. Warfarin
Q9. The following are the risk factors for post-
operative delirium except:
A. Baseline dementia
B. Poor vision/hearing
C. Presence of infection
D. Age less than 65 years
Q10. The incidence of postoperative atrial
fibrillation following open abdominal
aortic reconstruction is:
A. <5%
B. 5%–10%
C. 11%–15%
D. >15%
Q11. The most important risk factor for postop-
erative renal failure following open aortic
reconstruction is:
A. Mean blood pressure of 60 mmHg for
2 hours
B. Warm renal ischemia time of 30 minutes
C. Need for blood transfusion
D. Preoperative chronic kidney disease
Q12. The peak incidence of heparin-induced
thrombocytopenia following open aortic
reconstruction is on postoperative days:
A. 0–4
B. 5–10
C. 11–15
D. 16–20
Q13. A 70-year-old man with a history of atrial
fibrillation with a CHADS score of 2 on
apixaban is scheduled to undergo open
juxtarenal AAA repair. When should
apixaban be stopped?
A. Stop apixaban 24 hours before the
operation
B. Stop apixaban 48 hours before the
operation
C. Stop apixaban 5 days before the
operation
D. The patient should undergo hemodialysis
to clear the apixaban
Q14. A 76-year-old man presents to the ER with
dizziness and presyncope. The patient is
in atrial fibrillation with heart rate of
110 per minute. CTA of the neck shows less
than 50% stenosis of the bilateral internal
carotid arteries with a hypoplastic right
vertebral artery and the left vertebral
artery has 50% stenosis at its origin. CT
scan of the brain shows chronic white
matter changes. The optimal management consists of:
A. Vertebral artery transposition into the
common carotid artery
B. Urgent cardiology consult
C. ENG consult
D. Discharge patient on antiplatelet medica-
tion and beta-blockers
36 Section 4: Vascular Medicine
RATIONALE 1–14
1. RATIONALE
Antiplatelet medications are recommended for secondary prevention of noncardioembolic
ischemic stroke and TIA. Clopidogrel, extended-release dipyridamole, cilostazol, and ticagrelor have been studied for stroke prevention. The effect of antiplatelet medications is achieved
through several mechanisms. Aspirin irreversibly blocks the cyclooxygenase (COX) activity of
the prostaglandin H synthase 1 and 2 (COX 1 and COX 2). COX 1 inhibition permanently alters
the thromboxane A2–dependent platelet aggregation and vasoconstriction. Dipyridamole and
cilostazol are phosphodiesterase inhibitors. Clopidogrel, prasugrel, and ticagrelor inhibit the
adenosine-dependent platelet aggregation. Clopidogrel and prasugrel need activation by the
cytochrome P-450 enzyme. Aspirin and extended-release dipyridamole are superior to aspirin
alone in preventing major vascular events. The optimal medical management for carotid stenosis is antiplatelet medication, statins, targeted blood pressure reduction, and smoking cessation.
Guideline-directed treatment of diabetes mellitus, physical activity, medication and diet, and
evaluation of sleep apnea are important in reducing the risk of stroke.
Correct Answer A Ticagrelor
Reference
Marquardt, L., Geraghty, O. C., Mehta, Z., & Rothwell, P. M. (2010). Low risk of ipsilateral stroke in
patients with asymptomatic carotid stenosis on best medical treatment: a prospective, population-based study. Stroke, 41(1), e11–17. PMID: 19926843
2. RATIONALE
According to the results of the Stroke Prevention by Aggressive Reduction of Cholesterol Levels
(SPARCL) trial, treatment with atorvastatin in patients with carotid stenosis as compared to
placebos was associated with a 33% reduction in the risk of any stroke. In 2004 systematic reviews
and meta-analysis of randomized trials testing statin drugs concluded that each 10% reduction in
LDL was estimated to reduce the risk of all strokes by 15.6%. For patients undergoing interventions
such as carotid artery stenting and statin treatment, the incidence of cardiovascular events was
significantly lower in patients with statin pretreatment than in those without pretreatment. For
patients with symptomatic carotid stenosis, a perspective population-based study from Denmark
reported that the early risk of recurrent stroke in patients with symptomatic carotid stenosis is
dramatically reduced following urgent aggressive medical therapy, including statins.
Correct Answer A Atorvastatin
Reference
Amarenco, P., Bogousslavsky, J., Callahan, A., 3rd, et al. (2006). High-dose atorvastatin after stroke or
transient ischemic attack. N Engl J Med, 355(6), 549–559. PMID: 16899775
3. RATIONALE
CREST-2 is an ongoing trial to evaluate CEA or CAS compared to intensive medical management for asymptomatic carotid stenosis of 70–99%. Intensive medical management consists of
aspirin 325 mg daily, with patients undergoing carotid stenting (CAS) also receiving clopidogrel
in addition to aspirin for 30–90 days. The goal of systolic blood pressure is ≤ 140 mmHg and an
Section 4: Vascular Medicine 37
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LDL of <70 mg/dL. For patients with hyperlipidemia who are not able to reach the target LDL
with statin therapy, treatment with injectable PCK9 inhibitors is a good option, as these medications have shown to reduce cardiovascular events in patients with hyperlipidemia
Correct Answer C <70 mg /dL
Reference
Howard, V. J., Meschia, J. F., Lal, B. K., et al. (2017). Carotid revascularization and medical manage-
ment for asy mptomatic carotid stenosis: protocol of the CREST-2 clinical trials. Int J Stroke, 12(7),
770–778. PMID: 28462683
4. RATIONALE
The extent to which the cardiac assessment is to be performed prior to a vascular procedure
depends on the overall procedural risks, the patient’s comorbidities, and the patient’s exercise
capacity. A patient who is undergoing a low-risk percutaneous intervention may be sufficiently
cleared by a history that is negative for chest pain and shortness of breath, while those who
require general anesthesia at a minimum should have a 12-lead electrocardiogram prior to
open arterial reconstruction. Patients selected to undergo high-risk open repair such as open
abdominal aortic reconstruction, lower extremity bypass, or any patients with a significant history of cardiac disease including unstable angina, known cardiac arrhythmias, severe valvular
disease, or congestive heart failure should undergo evaluation by a cardiologist first. Patients
with unstable or stable angina involving the left main coronary artery or triple-vessel disease
should undergo coronary revascularization prior to major vascular reconstruction. When
patients who have reconstructed coronary artery disease need an alternative intervention,
existing coronary artery disease should be treated with balloon angioplasty or bare metal stent
placement followed by dual antiplatelet therapy for 4–6 weeks.
Correct Answer D Preintervention testing is not necessary
Reference
Malek, J., & McElroy, I. (2020). Preoperat ive risk assessment. In S. S. Hans & M. F. Conrad (Eds.), Vascular
and endovascular complications: a practical approach (pp. 1–5). Boca Raton, FL: CRC Press.
5. RATIONALE
Pulmonary complications are more common following major open vascular reconstruction
performed via a thoracic or thoracoabdominal incision. Active smokers are counseled to stop
smoking for at least 2 weeks prior to moderate- and high-risk procedures to decrease the incidence of pulmonary complications. Patients are at highest risk for complications within the first
2 months of quitting smoking, and their risk becomes equal to a nonsmoker after 6 months. For
patients with long-standing tobacco use, COPD, and poor baseline respiratory function, preoperative pulmonary function tests and arterial blood gases are recommended. These patients
should be started on bronchodilators for at least 2 weeks prior to open arterial reconstruction.
Correct Answer D Cessation of smoking within 2 months of the operation
Reference
Malek, J., & McElroy, I. (2020). Preoperat ive risk assessment. In S. S. Hans & M. F. Conrad (Eds.), Vascular
and endovascular complications: a practical approach (pp. 1–5). Boca Raton, FL: CRC Press.
38 Section 4: Vascular Medicine
6. RATIONALE
For patients at risk for contrast-induced nephropathy prehydration with normal saline for
12 hours, use of diluted contrast (1:1 with normal saline), reducing the volume of the contrast,
and continuation of intravenous normal saline for 12 hours following arteriography have a beneficial effect. Whenever possible, CO2 angiography should be substituted in place of iodinated
contrast in patients with CKD, as it does not have allergic potential or risk of renal toxicity. A
CO2 angiography study may be inadequate for visualization of infrapopliteal arteries. Contrastenhanced MRA with gadolinium in the presence of CKD is associated with nephrogenic
systemic fibrosis, and there has been a recent resurgence regarding the application of noncontrast MRA techniques in the evaluation of peripheral artery disease. Newer approaches such as
quiescent-interval slice-selective, velocity-sensitive, three-dimensional fast spin echo magnetic
resonance angiography is an attractive alternative to CTA or DSA.
Correct Answer C Preprocedure hydration with normal saline for 12 hours followed by postprocedure hydration with normal saline, reducing the volume of the contrast and use of diluted
contrast and use of CO2 angiography whenever feasible
Reference
Gleeson, T. G., & Bulugahapitiya, S. (2004). Contrast-induced nephropathy. AJR Am J Roentgenol,
183(6), 1673–1689. PMID: 15547209
7. RATIONALE
The decision to transfuse should be based on clinical assessment of the patient’s results of laboratory tests and evidence-based guidelines. Pooled results from three trials with 2364 participants showed that a restrictive hemoglobin transfusion trigger of <7 g/dL resulted in reduced
in-hospital mortality, total mortality, rebleeding, acute coronary syndrome, pulmonary edema,
and bacterial infections compared with a more liberal strategy.
1
Another clinical trial showed that a low trigger (Hgb <8.0 gm/dL) was associated with a higher
rate of death or major complications and that further trials were recommended.
2
Correct Answer D Hemoglobin less than 7 gm/dL
References
1. Salpeter, S. R., Buckley, J. S., & Chatterjee, S. (2014). Impact of more restrictive blood transfusion
strategies on clinical outcomes: a meta-analysis and systematic rev iew. Am J Med, 127(2), 12 4–131.
e123. PMID: 24331453
2. Møller, A., Niel sen, H. B., Wetterslev, J., et al. (2019). Low vs high hemoglobin t rigger for t ransfusion in
vascular surgery: a randomized clinical feasibility trial. Blood, 133(25), 2639–2650. PMID: 30858230
8. RATIONALE
The procoagulant effects of recombinant factor XA (Andexanet alfa) are anchored through the
ability to bind to and sequester factor XA inhibitors. The increase in available factor XA reduces
anticoagulant action. In clinical trials the median decline in anti–factor XA activity for apixaban or rivaroxaban was 88% or higher. Andexanet alfa also binds tissue factor inhibitor pathways or peptides that inhibit factor XA. Adverse effects include deep vein thrombosis, arterial
thrombosis, pulmonary embolism, and ischemic stroke. Idarucizumab is used for the reversal
of dabigatran.
Section 4: Vascular Medicine 39
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Correct Answer C Recombinant factor XA (Andexxa)
Reference
Siegal, D. M., Curnutte, J. T., Connolly, S. J., et al. (2015). Andexanet alfa for the reversal of factor XA
inhibitor activity. N Engl J Med, 373(25), 2413–2424. PMID: 26559317
9. RATIONALE
Delirium occurs in approximately 80% of elderly patients admitted to a critical care unit.
Delirium increases the length of stay in a critical care unit and increases the days that a patient
is on a ventilator, as well as morbidity and mortality. The risk of delirium is increased in hearing
and visually impaired individuals, use of narcotics during the hospital stay, use of restraints,
prehospital cognitive impairment, heavy alcohol abuse, and polypharmacy withdrawals.
Inadequate pain control may also contribute to delirium. Delirium is characterized by a disorganized thought process, inattention, and altered level of consciousness. Normalization of the
patient’s environment, usual sleep–wake cycles, presence of family at the bedside, and access to
glasses and hearing aids is helpful. Removal of restraining devices and early immobilization are
also beneficial. Benzodiazepine and diphenhydramine may contribute to delirium and therefore should be avoided. Dexmedetomidine is a useful drug in the management of delirium.
Correct Answer D Age less than 65 years
Reference
Barr, J., Fraser, G. L., Puntillo, K., et al. (2013). Clinical practice guidelines for the management of pain,
agitation, and delirium in adult patients in the intensive care unit. Crit Care Med, 41(1), 263–306.
PMID: 23269131
10. RATIONALE
The incidence of atrial fibrillation following open abdominal aortic reconstruction nears 10%.
Factors predisposing to atrial fibrillation include advanced age, hypertension, coronary artery
disease, valvular heart disease, ischemic cardiomyopathy, prior history of atrial fibrillation, and
chronic obstructive pulmonary disease. Treatment is based on controlling the heart rate and
reducing the risk of embolic events. In hemodynamically unstable patients, electric cardioversion is the treatment of choice. In patients who are hemodynamically stable, rate control with
beta-blockers, calcium channel blockers, and amiodarone is often implemented. If atrial fibrillation persists for longer than 48 hours, anticoagulation with unfractionated heparin should be
considered.
Correct Answer B 5%–10%
Reference
Valentine, R. J., Rosen, S. F., Cigarroa, J. E., et al. (2001). The clinical course of new-onset atrial fibrilla-
tion after elective aortic operations. J Am Coll Surg, 193(5), 499–504. PMID: 11708506
11. RATIONALE
Acute kidney injury has been shown to occur in as many as one in five patients postoperatively.
Patients who have preoperative chronic kidney disease have the highest risk of postoperative renal failure. Other factors include prolonged perioperative hypotension, prolonged renal
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