From the Western Vascular Society
Postprocedural microembolic events following
carotid surgery and carotid angioplasty
Maureen M. Tedesco, MD,aJason T. Lee, MD,aRonald L. Dalman, MD,aBarton Lane, MD,b
Christopher Loh, MD,cJason S. Haukoos, MD, MS,d,eJoseph H. Rapp, MD,fand
Sheila M. Coogan, MD,gStanford, Los Angeles, and San Francisco, Calif; Denver, Colo; and Houston, Tex
Objective: The relative safety of percutaneous carotid interventions remains controversial. Few studies have used
diffusion-weighted magnetic resonance imaging (DW-MRI) to evaluate the safety of these interventions. We compared
the incidence and distribution of cerebral microembolic events after carotid angioplasty and stenting (CAS) with distal
protection to standard open carotid endarterectomy (CEA) using DW-MRI.
Methods: From November 2004 through August 2006, 69 carotid interventions (27 CAS, and 42 CEA) were performed
in 68 males at a single institution. Pre- and postprocedure DW-MRI exams were obtained on each patient undergoing
CAS and the 20 most recent CEA operations. These 46 patients (47 procedures as one patient underwent bilateral CEAs
in a staged fashion) constitute our study sample, and the hospital records of these patients (27 CAS and 20 CEA) were
retrospectively reviewed. The incidence and location of acute, postprocedural microemboli were determined using
DW-MRIs and assessed independently by two neuroradiologists without knowledge of the subjects’ specific procedure.
Results: Nineteen CAS patients (70%, 95% confidence interval [CI]: 42%-81%) demonstrated evidence of postoperative,
acute, cerebral microemboli by DW-MRI vs none of the CEA patients (0%, 95% CI: 0%-17%) (P < .0001). Of the 19 CAS
patients with postoperative emboli, nine (47%) were ipsilateral to the index carotid lesion, three (16%) contralateral, and
seven (36%) bilateral. The median number of ipsilateral microemboli identified in the CAS group was 1 ( interquartile
ranges [IQR]: 0-2, range 0-21). The median number of contralateral microemboli identified in the CAS group was 0
(IQR: 0-1, range 0-5). Three (11%) CAS patients experienced temporary neurologic sequelae lasting less than 36 hours.
These patients suffered 12 (six ipsilateral and six contralateral), 20 (19 ipsilateral and one contralateral), and zero
microemboli, respectively. By univariate analysis, performing an arch angiogram prior to CAS was associated with a
higher risk of microemboli (median microemboli 5 vs none, P ?.04)
Conclusions: Although our early experience suggests that CAS may be performed safely (no permanent neurologic deficits
following 27 consecutive procedures), cerebral microembolic events occurred in over two-thirds of the procedures despite
the uniform use of distal protection. Open carotid surgery in this series seems to offer a lower risk of periprocedural
microembolic events detected by DW-MRI. (J Vasc Surg 2007;46:244-50.)
Over 700,000 strokes occur in the United States each
year resulting in major disability and over 160,000 annual
deaths. Stroke is the third leading cause of death in the
United States.1 Strokes most frequently result from acute
ischemia, 20% of which are due to atherosclerotic occlusive
disease in the carotid artery.2 While carotid endarterectomy
(CEA) has been considered the gold standard for the
surgical treatment of symptomatic or high-grade carotid
occlusive disease,3 numerous trials now suggest that carotid
angioplasty and stenting (CAS) has clinical equipoise to
CEA and may offer some advantages to CEA in the man-
agement of specific subsets of patients with critical carotid
Distal protection devices (DPDs) were added to the
procedural armamentarium of catheter-based carotid inter-
ventions specifically to reduce the risk of periprocedural
embolic events.11-13 Several recent studies have questioned
the efficacy of DPD in limiting early and late microembolic
events.14-18 The intermediate and long-term significance
of these events remains uncertain. To our knowledge,
microembolic events within 48 hours following CEA and
CAS have not been compared concurrently in a single
institution using identical imaging protocols. In this study,
we performed diffusion-weighted magnetic resonance im-
catheter-based carotid revascularization to determine
whether either approach conferred relative protection
against periprocedural microembolic events and to deter-
From the Division of Vascular Surgeryaand Division of Neuroradiology,b
Stanford University Medical Center, Stanford; the Division of Neurora-
diology, University of California, Los Angeles Medical Center, Los An-
geles;cthe Department of Emergency Medicine, Denver Health Medical
Center, Denver;dthe Department of Emergency Medicine, University of
Colorado Health Sciences Center, Denver;ethe Division of Vascular
Surgery, University of California, San Francisco Medical Center, San
Francisco;fand the Division of Vascular Surgery, University of Texas,
Houston Medical Center, Houston.g
Competition of interest: none.
Presented at the Twenty-first Annual Meeting of the Western Vascular
Society, La Jolla, Calif, Sept 16-19, 2006.
Reprint requests: Jason T. Lee, MD, Division of Vascular Surgery H3600,
Stanford University Medical Center, 300 Pasteur Drive, Stanford, CA
94305 (e-mail: email@example.com).
Copyright © 2007 by The Society for Vascular Surgery.
mine whether specific risk factors for such events could be
determined based on patient-specific anatomic and proce-
Carotid endarterectomy. All CEA procedures were
performed under general anesthesia. Patients were rou-
tinely given aspirin 81 mg prior to the CEA (the night
before or the morning of the operation) and all patients
were given heparin (100 U/kg) routinely before cross-
clamping. Intraoperative electroencephalogram (EEG)
monitoring by anesthesia was used in all cases. Selective
shunting was performed in all patients who had a contralat-
eral occlusion, an incomplete Circle of Willis identified by
preprocedure MRI, intraoperative EEG changes, or who
were undergoing treatment for symptomatic stenosis. One
surgeon routinely shunted all CEA patients irrespective of
tacking sutures, patch angioplasty, and primary reconstruc-
tion were utilized based on intraoperative evaluation and
Carotid angioplasty and stenting. Patients were ei-
ther given ASA 81 mg and clopidogrel 300 mg 12 hours
prior to CAS or were treated with ASA 81 mg and clopi-
dogrel 75 mg daily for 1 week prior to CAS. All CAS
procedures were performed from a femoral approach using
local anesthesia and intravenous sedation. Arch angiogra-
phy at the time of the procedure was performed in patients
based on the preference of the surgeon performing the
intervention. Angiography was not performed in patients
who demonstrated significant stenosis or ulceration in the
arch based on review of the preoperative magnetic reso-
nance angiogram (MRA). If arch angiography was per-
formed, a 5 Fr pigtail catheter (Angiodynamics, Queens-
bury, NY) was placed into the ascending aorta and the arch
run was completed with 30 mL of contrast at a rate of
15mL/second. A 6 Fr Shuttle sheath (Cook Inc, Bloom-
ington, Ind) was then placed into the descending thoracic
aorta via the common femoral artery. All patients were
heparinized to maintain an activated clotting time (ACT)
?280. The target common carotid artery was cannulated
using a hydrophilic glide wire over a 6.5 Cook selective
catheter (JB1, H1, or Vitek). In tortuous arteries, the
external carotid artery was cannulated prior to advancing
the Shuttle sheath into the common carotid artery. The
Accunet distal protection device and Acculink (Guidant,
Inc, Sunnyvale, Calif) self-expanding carotid stents were
used in all cases. (One case required a buddywire and
predilatation with a 2 mm coronary balloon to cross the
carotid lesion.) All lesions were predilated with a 4 mm ?
20 mm balloon. Following stent deployment, lesions were
postdilated using a 5 mm ? 20 mm balloon if there was
evidence of residual stenosis. Completion angiogram was
performed in all patients. A 6 Fr Perclose device (Abbott
Vascular, Sunnyvale, Calif) was utilized based on surgeon
preference and suitable femoral artery anatomy. At the end
of the procedure, heparin reversal with protamine was
performed in some patients based on surgeon preference.
MRI imaging examination. All patients undergoing
intervention had a pretreatment MRI and a posttreatment
MRI performed within 48 hours of the procedure. The
majority (?80%) of the posttreatment DW-MRIs were
obtained the following morning (18 to 24 hours post).
Imaging was performed with a 1.5-T apparatus (GE Signa
Excite HD 12.0, Piscataway, NJ, USA) equipped with a
head coil. The pre- and posttreatment MR imaging rou-
tinely included the following: axial spin-echo T1-
weighted, fast-spin echo T2-weighted, fluid-attenuated
postcontrast spin-echo T1-weighted imaging. The DW
images were acquired with an echo-planar sequence. An
isotropic sequence was used (6500/97/1 TR/TE/NEX,
field of view 280 mm, matrix 128 ? 128, with b values of 0
and 1000 s/mm2).
The DW images were then evaluated by two neurora-
diologists blinded to the clinical status of the patients. Any
presence of new hyperintensity in the brain was interpreted
as a new ischemic lesion called a microembolism. Microem-
boli were recorded in terms of location and number for all
Data collection. This study was approved by the Stan-
ford Human Research Protection Program. From Novem-
ber 2004 through August 2006, 69 consecutive carotid
interventions were performed in a total of 68 patients (27
CAS procedures and 42 CEA procedures with one patient
undergoing bilateral CEA in a staged fashion) at the Vet-
erans Affairs Palo Alto Health Care System. Patients who
were not eligible for MRI (due to pacemaker, claustropho-
bia, etc) and, therefore, did not have preoperative and
postoperative MRIs, and all conversions from CAS to CEA
were excluded from this study. All procedures were per-
formed by board certified or board eligible vascular sur-
geons. Treatment was nonrandomized and was directed
after assessment by a vascular surgeon. Patients deemed
high-risk for CEA were determined by the vascular surgeon
in consultation with cardiology and typical reasons for
offering CAS to these patients included recurrent carotid
disease, previous neck surgery, neck irradiation, and symp-
tomatic cardiac comorbidities.
ing history, hyperlipidemia as defined by the use of a lipid
lowering medications, history of coronary artery disease,
peripheral vascular disease, diabetes mellitus and hyperten-
sion as defined by the use of antihypertensive medications,
and obesity defined as body mass index ?30 were collected
retrospectively. We also investigated the records for a his-
tory of prior carotid intervention, history of contralateral
stenosis, history of stroke, and symptoms of the current
Lesions characteristics including degree of stenosis,
lesion length, ulceration, and arch anatomy determined by
a combination of preoperative duplex ultrasound, MRA, or
intraoperative angiography was recorded. Degree of steno-
sis was determined using North American Symptomatic
Carotid Endarterectomy Trial (NASCET) criteria.4 Lesion
length was measured along the vessel where it was nar-
JOURNAL OF VASCULAR SURGERY
Volume 46, Number 2
Tedesco et al 245
rowed greater than 50%. Arch anatomy was graded using
Schneider’s classification.14 Procedure-specific CAS data
included total contrast used, fluoroscopy time, and the use
of arch angiography. Data collected for CEA patients in-
and need for resection and interposition grafting.
Periprocedural neurologic status was determined based
on review of the entirety of the medical record (anesthetic
record, progress notes, nursing notes, discharge summa-
ries, and subsequent outpatient examinations). Two neu-
roradiologists who did not participate in the procedure and
who were unaware of the procedural status of individual
subjects (eg, type of procedure, laterality of index carotid
stenosis, etc.) independently reviewed the DW-MRIs im-
ages for evidence of acute microembolic events, noting
number and location. Discrepancies were noted between
the reviewers; images were reviewed by both to reach
consensus. The reviewers disagreed on presence of new
microemboli in two cases (4.2%).
Statistical analysis. All data were collected on closed-
response data collection instruments and entered into an
electronic spreadsheet (Microsoft Excel, Microsoft Corpo-
ration, Redmond, Wash). Data were then transferred into
native SAS format using translational software (dfPower
DBMS/Copy, DataFlux Corporation, Cary, NC). All sta-
tistical analyses were performed using SAS Version 9.1
(SAS Institute, Inc, Cary, NC).
Descriptive statistics were calculated for all variables.
Continuous data are reported as medians with interquartile
ranges (IQRs) and categorical data are reported as percent-
ages with 95% confidence intervals (CIs). Bivariate statisti-
cal techniques, including the Wilcoxon rank sum test and
Fisher exact test, were used when appropriate. Statistical
significance was defined by a P value ? .05. No a priori
sample size was calculated. Interobserver variability was
Forty-six consecutive male patients underwent 47 in-
ternal carotid artery revascularization procedures with pre-
operative and postoperative DW-MR imaging from
November 2004 through August 2006. Twenty-seven pa-
tients underwent CAS with a distal protection device, and
19 patients underwent CEA (one patient had bilateral
CEA). All procedures were performed by one or more of
three vascular surgeons (JTL, RLD, and SMC), three vas-
cular fellows, and various general surgery residents.
With respect to CEA technique, 6/20 were performed
with indwelling shunts, 7/20 used distal tacking sutures,
and 18/20 were closed incorporating patch material (17
Dacron patch, one autogenous saphenous vein). One CEA
patient underwent adjunctive redundant carotid resection
with primary re-anastamosis.
Median patient age for CAS was 70 (IQR: 59 – 77)
years vs 64 (IQR: 59 – 79) for patients undergoing CEA
(P ?.9). Nearly two thirds (64%) of the entire cohort had
suffered prior ipsilateral cerebral embolic events. Three
quarters of the entire cohort were current smokers or had a
history of tobacco use. Nine patients, all in the CAS group,
had previously undergone CEA for disease in the ipsilateral
carotid artery. Overall patient characteristics are summa-
rized in Table I.
Nineteen (70%, 95% CI: 42%-81%) CAS patients dem-
onstrated evidence of acute postoperative cerebral micro-
emboli by DW-MRI vs 0 (0%, 95% CI: 0%-17%) CEA
patients (P ? .0001). Within the CAS group with micro-
emboli, nine (47%) were ipsilateral, seven (36%) were bilat-
eral, and three (16%) were contralateral to the index carotid
tified in the CAS group was 1 (IQR: 0 – 2, range: 0 – 21).
The median number of contralateral microemboli identi-
fied in the CAS group was 0 (IQR: 0-1, range: 0-5).
Three CAS patients experienced periprocedural neuro-
logic sequelae (11%) versus none (0%) of the CEA patients.
Of the CAS patients with postprocedure neurologic find-
ings, they were all transient (resolved within 36 hours), and
two of these patients demonstrated microemboli on DWI.
As a predictor of neurologic events after CAS, microemboli
Table I. Patient characteristics
CAS (n ? 27) (%) CEA (n ? 20) (%) Total (n ? 47) (%)P
Median age (IQR)
Previous ipsilateral CEA
CAS, Carotid artery stent; CEA, carotid endarterectomy; IQR, interquartile range; HTN, hypertension; DM, diabetes mellitus; CAD, coronary artery disease;
COPD, chronic obstructive pulmonary disease; PVD, peripheral vascular disease.
*Symptomatic defined by a history of a TIA or amaurosis fugax in the previous 6 months.
JOURNAL OF VASCULAR SURGERY
246 Tedesco et al
on DWI demonstrated a sensitivity of 66%, specificity of
29%, and a negative predictive value of 88%. One patient
with 12 microemboli (six contralateral) experienced ataxia
(Fig 1). In this case, fluoroscopy time was 14 minutes, a
classified as type 1. A second patient with 20 microemboli
(one contralateral) experienced contralateral weakness in
the upper and lower extremities resolving within 36 hours
after CAS (Fig 2). In this patient, fluoroscopy time was 15
minutes, arch angiography was performed, and the patient
had a type I arch. The third patient who developed minor
cognitive sequelae after CAS had no evidence of DW-MRI
abnormalities despite a fluoroscopy time of 26 minutes (no
arch angiogram performed, type I arch identified on pre-
operative DW-MRI); cognition returned to baseline within
arch angiogram associated with the development of micro-
emboli in the CAS patients (P ? .04). Table II depicts the
patient and procedural characteristics of the CAS group.
None of the CEA patients demonstrated postoperative
neurologic symptoms. Table III summarizes the number of
microemboli based on the neurologic outcome of the
In this retrospective analysis, 70% of the patients who
underwent CAS demonstrated postprocedure cerebral mi-
croemboli on DW-MRI compared to 0% of the CEA pa-
tients. Of the CAS patients with DW-MRI changes, only
three (15%) demonstrated neurologic changes, all of which
resolved within 36 hours postprocedure. Performing arch
angiography was the only procedural characteristic that was
Fig 1. Pre- and postoperative diffusion-weighted magnetic reso-
nance imaging (DW-MRI) of a 64-year-old male who was noted 4
years after Right carotid endarterectomy (CEA) to have recurrent
Right carotid stenosis of 90%. Right carotid angioplasty and stent-
ing (CAS) was performed and patient noted gait disturbance and
diplopia postprocedure that resolved after 36 hours. DW-MRI
done 24 hours after the procedure demonstrated 12 microemboli,
six ipsilateral and six contralateral. Red arrows demonstrate punc-
tate emboli in the Right temporal and Left occipital regions.
Fig 2. Pre- and postoperative diffusion-weighted magnetic reso-
nance imaging (DW-MRI) of a 62-year-old male with significant
cardiac and pulmonary comorbidities with symptomatic 70% Left
carotid stenosis. Patient underwent Left carotid angioplasty and
stenting (CAS) and was noted postprocedure to have Right sided
upper extremity weakness that resolved after 24 hours. Postop
DW-MRI demonstrated 20 microemboli, 19 ipsilateral, and one
contralateral to the index lesion. Red arrows demonstrate punctate
emboli in the Left frontal and parietal regions and the Right
Table II. Procedural characteristics of patients who
underwent carotid artery stenting (n ? 27)
of emboli IQR RangeP
Type I arch
Type II/III arch
No arch angiogram
Lesion ?5 mm
Lesion ?5 mm
Previous ipsilateral CEA
de novo lesion
CCA, Common carotid artery; IQR, inter quartile range.
P values are for univariate comparisons by the Wilcoxon rank sum test or
Fisher exact test.
*Symptomatic defined by a history of a TIA or amaurosis fugax. Asymptom-
atic patients denied a history of temporary neurologic complaints.
Table III. Periprocedural neurologic events and mean
number of microemboli
No event (n ? 24)
TIA (n ? 3)
N ? 20
CAS, Carotid artery stent; CEA, carotid endarterectomy.
JOURNAL OF VASCULAR SURGERY
Volume 46, Number 2
Tedesco et al 247
significantly associated with developing an increased num-
ber of microemboli postintervention.
There have been several recent publications document-
stenting procedures.15-18 Reports have demonstrated new,
cerebral microembolic lesions following CAS ranging from
4%18 to 72%19 of cases. While many have studies have
compared CAS with and without cerebral protection de-
vices, few studies compare both CAS and CEA within the
same study. In addition, most of the emboli reported have
been clinically silent.
The prevalence of microembolic events experienced by
CAS patients in our series falls at the high end of contem-
porary reports and deserves further discussion. First, there
may be a publication bias in reporting unfavorable results.
Secondly, most prior studies obtained preprocedural MR
images within 24 hours prior to CAS. In our series, baseline
MR studies were obtained up to several weeks prior to the
procedure, allowing for the possibility that interim events
may have occurred and erroneously ascribed to procedure-
related emboli, particularly in symptomatic patients. Tim-
ing of postprocedural imaging also varied; DW-MRI were
obtained between 12 and 48 hours following the study.
Operator experience represents another potential variable.
The learning curve of interventionalists has been shown to
be a major factor in assessing periprocedural complications
in CAS.20 Since beginning our CAS program, we have
continually modified our technique to reduce the likeli-
hood of inducing emboli, including omitting arch aortog-
raphy when preprocedure MRI provide sufficient anatomic
detail, initiating anticoagulation prior to passage of wires or
catheters into the ascending or transverse arch, and mini-
mizing need for catheter exchanges.
DW-MRI is highly sensitive to acute changes in cere-
bral perfusion and has been extensively employed to ana-
lyze early occurrence of cerebroembolic events.13 The
long- term clinical significance of acute DWI abnormalities
remains uncertain. Lesions that increase in intensity on subse-
images were not obtained in our study. Most asymptomatic
DW-MRI abnormalities resolve within weeks.
The utility of DPD in preventing periprocedural em-
boli following CAS is moderately well supported.21 In one
study, the use of cerebral protection device reduced the
incidence of cerebral infarction significantly; there was a
25% stroke rate in patients who underwent CAS without
protection compared to 5% clinically detected strokes in
patients who did have cerebral protection devices uti-
lized.22 Many studies, though, have not been powered to
show a difference in stroke rates comparing CAS with and
without distal protection. Early results from the Carotid
Revascularization Endarterectomy Versus Stenting Trial
(CREST) demonstrated a trend towards decreased stroke
rates in CAS with distal protection, but this was not statis-
tically significant.23 Despite relatively modest supporting
data, CAS with adjunctive DPD is now considered the
standard of care for catheter-based carotid intervention. In
the Stenting with Angioplasty and Protection in Patients at
High Risk for Endarterectomy (SAPPHIRE) trial, CAS
with DPD resulted in a major ipsilateral stroke rate at one
non-ipsilateral stroke rate of 1.9%,7 confirming that intra-
operative DPD deployment does not eliminate embolic
risk, at least for the current generation of DPDs.
In this study, 16% of the new microemboli identified
were contralateral to the treatment side, while 36% were
bilateral. Possible explanations for why contralateral micro-
emboli occur are likely related to catheter manipulation.
For example, arch angiography in the presence of aortic
emboli despite only catheterizing the target lesion side.
Another reason is the technique typically employed to
catheterize the left common carotid, which involves precise
withdrawal of a shaped catheter (usually JB1 or H1) from
the arch and first allowing it seek the innominate artery. At
the outset of our CAS experience, arch angiography was
routinely performed on all patients prior to CAS. Some-
what in response to the apparently high prevalence of
DW-MRI abnormalities, we later eliminated this step as
redundant in many patients with sufficient anatomic detail
provided by MRI. Given these findings, we believe arch
undergo preintervention MRI or those without significant
anatomic detail to guide catheter placement.
While univariate analysis revealed that there is a statis-
tically significant difference in number of emboli associated
with arch angiograms (Table II), we believe excessive ma-
nipulation of the guidewire or catheters puts the patient at
risk for embolization. Interestingly, a more challenging
arch (type II or type III) was not found to be higher risk for
embolization. Fluoroscopy time and contrast utilized were
also studied as variables and found not to be related to
microemboli formation. These parameters may have been a
surrogate marker for case complexity, although there was
no correlation between longer fluoroscopy time or in-
creased amount of contrast with postprocedural microem-
A significant limitation of this current study is sample
size. With a limited number of both CAS and CEA cases,
there is a considerable risk of a type II error. As depicted in
Table I, the CAS and CEA groups differ with respect to
comorbidities, as well, which may explain some of the
difference in microemboli between the groups. Further
investigation into risk factors associated with the presence
of postprocedural microemboli is required.
Other larger, randomized controlled clinical trials have
compared CAS and CEA in symptomatic patients, evaluat-
ing for periprocedural events and outcomes such as stroke
and death. The Stent-Supported Percutaneous Angioplasty
of the Carotid Artery versus Endarterectomy SPACE trial
was unable to show that CAS was not inferior to CEA for
severe, symptomatic stenosis.24 Similarly, the Endarterec-
tomy verses Angioplasty in Patients with Symptomatic,
Severe Carotid Stenosis (EVA 3S) trial reported signifi-
cantly lower death and stroke rates in CEA patients com-
pared to CAS patients. This trial was prematurely con-
JOURNAL OF VASCULAR SURGERY
248 Tedesco et al
cluded due to the significant outcome differences found
between the two interventions.25 The findings in this cur-
rent study are consistent with the theme that CEA may be
safer when looking at the incidence of postprocedural
microemboli when compared with CAS.
While no other studies have utilized DW-MRI to de-
tect cerebral microemboli after CEA, microemboli have
been reported after CEA in up to 70% of patients when
monitoring with other modalities such as intraoperative
transcranial Doppler (TCD).26,27 This striking discrepancy
suggests that many of the particles detected on TCD may
also not be clinically significant, since neurologic event
rates in these studies have been in the acceptable 1% to 4%
rate.26 Another explanation may be that the microemboli
detected intraoperatively may have been resolved by the
Still another reason could be that with our small sample size
of only 20 CEAs that we have not yet detected the actual
incidence of microemboli following open surgery. Further
series of CEA and detection of microemboli using DW-MRI
are necessary to confirm this preliminary finding of our study.
Continuing uncertainty remains regarding the clinical
significance of DW-MRI lesions, and what they mean with
respect to long-term complications and neurocognitive
out of 22 patients with new neurologic symptoms follow-
ing CAS, while only one had new emboli seen on diffusion-
weighted imaging.28 Similarly, one of the patients in the
current study did not demonstrate any emboli on DW-
MRI, but did exhibit temporary neurologic sequelae.
Long-term follow-up with neurocognitive testing and re-
peated magnetic resonance T2- weighted imaging will pro-
vide better insight into the nature of these lesions.
In summary, based on currently available evidence,
there appears to be significantly less risk of developing
microemboli detected by DW-MRI after open carotid end-
arterectomy (CEA) than CAS with current DPD technol-
elucidated procedural selection for carotid lesions should
incorporate the differential risk associated with these two
widely differing approaches to procedural-based stroke risk
Conception and design: MT, JL, SC, RD
Analysis and interpretation: MT, SC, JL
Data collection: MT, JL, BL, CL
Writing the article: MT, JL
Critical revision of the article: MT, JL, RD
Final approval of the article: JL
Statistical analysis: JH
Obtained funding: Not applicable
Overall responsibility: JL
MT and JL contributed equally to this work.
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