Keywords
casper stent - double-layer stent - carotid stenosis - angioplasty - stroke
Palavras-chave
stent casper - stent de dupla camada - estenose carotídea - angioplastia - AVC
Introduction
Extracranial stenosis of the internal carotid artery (ICA) accounts for between ∼
10 and 15% of ischemic strokes, which is one of the main causes of death and disability
in the world.[1] The advent of vascular microsurgery brought stent angioplasty as a promising alternative
to ICA endarterectomy, especially for patients whose comorbidities increase their
surgical risk, in cases of restenosis after procedures, and in those with previous
radiation therapy of the cervical region.[2]
Stenting of the carotid artery is associated with long-term lower rates of stroke
after elective treatment of individuals with significant extracranial ICA stenosis.[3] However, this technique poses a risk of intraoperative cerebral embolism due to
mobilization of atherothrombotic materials after manipulation of the lesion, as well
as to plaque protrusion through the expanded stent struts. For this reason, special
attention has been paid to the design, material, and shape of the chosen stent.[4]
To reduce the embolic risk of the procedure, a dual-layer carotid stent model has
been introduced. In addition to the self-expanding nitinol outer layer that provides
support, its second micro mesh layer provides better plaque coverage while remaining
flexible.[5] Short-term outcomes following the use of these devices in elective environments
have proven to be promising.[6]
The Casper-RX carotid stent has the smallest area between closed cells of all carotid
stents on the market. Double-layer devices have delivered greater benefits regarding
atheroma plaque coverage and decreased likelihood of infarction due to the embolization
of atheroma plaques.[7]
Thus, the purpose of the present article is to study carotid artery stenosis recanalization
using a new model of double-layer stent, the Casper-RX, as well as to evaluate its
clinical behavior in a reference center for endovascular neurosurgery in Brazil.
Methodology
Design and Sample
Retrospective study of the medical records of 116 patients undergoing angioplasty
of the extracranial segment of the ICA using the Casper-RX stent from April 2015 to
December 2019 in a reference center service for endovascular neurosurgery in the city
of Blumenau, state of Santa Catarina, Brazil.
Inclusion and Exclusion Criteria
Symptomatic and asymptomatic patients who underwent endovascular treatment of stenosis
of at least 70% of the ICA with Casper-RX stent implantation from April 2015 to December
2019 were included. Insufficient data – such as segment loss within 30 days and absence
of radiological reports – were considered exclusion criteria.
Data Analysis
Categorical variables were expressed as absolute values (percentages), and quantitative
variables, as means ± standard deviation (SD) or medians (interquartile range [IQR])
as appropriate. Analyses were tabulated in Microsoft Excel 2020 (Microsoft Corporation,
Redmond, WA, USA) and analyzed using the SPSS Statistics for Windows version 17.0
(SPSS Inc., Chicago, IL, USA). Device safety and therapeutic success were evaluated,
as well as the rate of complications and restenosis, compared with literature data.
Variables
Epidemiological variables such as gender, age, and pre-existing comorbidities – diabetes
mellitus, hypertension, dyslipidemia, smoking, and heart disease were collected. Pretreatment
symptoms included headache, dizziness, ischemic stroke, and transient ischemic attack
(TIA). Regarding the carotid lesion, the degree of stenosis on the affected side,
laterality, treated bilaterality, presence of dissection, ulcerated plaque, and contralateral
occlusion were analyzed.
Regarding the surgical procedure, the access type (femoral or axillary), immediate
therapeutic success, intra- and postoperative events – from 90 days up to 6 months
-, use of a cerebral protection filter, and stent diameter were studied. The overall
neurological outcome of the individuals was evaluated using the 90-day modified Rankin
Scale (mRS). Technical success was evaluated by carotid Doppler ultrasonography (USG)
at least 6 months after the endovascular intervention. According to the degree of
stenosis, patients were divided into “absent stenosis” if < 30%, “residual stenosis”
if the persistence was between 30 and 40%, and “late stenosis” if they presented a
higher degree with onset after 6 months of follow-up. Stent occlusion was also analyzed.
The noninvasive preprocedural diagnostic methods used include magnetic resonance imaging
(MRI), computed tomography (CT), magnetic resonance angiography, angiotomography,
and carotid Doppler test. Regarding the invasive test, cerebral arteriography was
used in all procedures during angioplasty.
Procedure
Patients undergoing endovascular intervention had atheromatous disease in the extracranial
portion of the internal carotid artery, with a degree of stenosis between 70 and 99%,
were symptomatic, or had been incidentally diagnosed. They were first put under sedation
and total heparinization 10,000 UI, with femoral intra-arterial instillation of low
osmolarity nonionic contrast through a guide catheter. Then, cerebral angiographies
were performed to identify the precise site of stenosis and its degree. Brain protection
filters, such as Spider FX (Medtronic, 710 Medtronic Parkway, Minneapolis, MN, United
States of America), AngioGuard (Cordis 5452 Betsy Ross Dr, Santa Clara, CA, United
States of America), and EmPro (Microvention, Inc 35 Enterprise, Aliso Viejo, CA, United
States of America) were inserted. The filter passed through the stenosis and was then
deployed. The Casper-RX stents with diameters of between 7 and 9 mm adapted to the
wall, which allowed total correction of the affected arteries. After mapping and real-time
radioscopy, the stents were detached. The cerebral protection filters were removed,
and postoperative angiographies were performed, showing full coverage of the plaques
and correct device patency. The primary endpoint was achieved with the successful
placement of the device.
Antiplatelet Therapy
Double antiplatelet therapy was administered with aspirin 200 mg and clopidogrel 75 mg
to all patients, from 7 days before the procedure up to 3 months after the angioplasty.
Results
Epidemiological Variables, Symptoms, and Comorbidities
The mean age of the patients was 73 (66 to 79) years old; 79% were ≥ 68 years old.
Of the total sample, 61.2% were male. Regarding the clinical presentation, 111 (96%)
were symptomatic, mainly with dizziness (59.5% of the cases), ischemic stroke (33.6%)
and TIA (17.2%). The most prevalent comorbidities were arterial hypertension (90.5%),
and dyslipidemia (94%) ([Table 1]).
Table 1
Epidemiological and clinical characteristics
|
Characteristic
|
All cases
n = 116
|
|
Age (years old) (mean [IQR])
|
73 (66–79)
|
|
≥ 68 years old (n [%])
|
79 (68.1)
|
|
Gender (n [%])
|
|
|
Male
|
71 (61.2)
|
|
Female
|
45 (38.8)
|
|
Clinically documented symptoms (n [%])
|
|
|
Dizziness
|
69 (59.5)
|
|
Headache
|
7 (6)
|
|
Ischemic stroke
|
39 (33.6)
|
|
Transient ischemic attack
|
20 (17.2)
|
|
Comorbidities (n [%])
|
|
|
Arterial hypertension
|
105 (90.5)
|
|
Diabetes mellitus
|
43 (37.1)
|
|
Current smoker
|
29 (25)
|
|
Dyslipidemia
|
109 (94)
|
|
Cardiopathy
|
29 (25)
|
|
Stenosis in arteriography/Doppler
|
|
|
Degree (%), mean (IQR)
|
80 (70–92.5)
|
|
Ulceration (n [%])
|
112 (96.5)
|
|
Carotid dissection (n [%])
|
4 (3.4)
|
|
Side of occlusion (n [%])
|
|
|
Left
|
62 (53.5)
|
|
Right
|
54 (46.5)
|
|
Contralateral internal carotid artery (n [%])
|
|
|
Occlusion
|
10 (8.6)
|
|
Previous treatment
|
10 (8.6)
|
|
Neuroimaging before procedure (n [%])
|
|
|
MRI
|
21 (18.1)
|
|
CT scan
|
27 (23.3)
|
|
Arteriography
|
116 (100)
|
|
AngioMRI
|
11 (9.4)
|
|
Angiotomography
|
50 (43.1)
|
|
Carotid Doppler
|
75 (64.6)
|
Abbreviations: CT, computed tomography; IQR, interquartile range; MRI, magnetic resonance
imaging.
Preprocedural Stenosis Characteristics
Arteriography was the neuroimaging test of choice in all patients, allowing preoperative
assessment of the degree of stenosis, of the presence of ulcerated plaque, and of
dissecting pseudoaneurysm in the carotid arteries. Carotid Doppler test was performed
in 75 individuals (64.6%). Other imaging tests used are described in [Table 1]. The average duration of the procedure was ∼ 30 minutes.
Technical Success and Intraoperative Complications
The average diameter of the implanted devices was 8.0 mm, with no need for additional
stenting for complete coverage of the plaque. The surgical access was through the
femoral artery in all patients. In 114 patients (98.3%), a cerebral protection filter
was used during the procedure, mostly AngioGuard (81%), EmPro (13.8%), and Spider
(2.6%). There were neither intra- nor postoperative complications in the two cases
performed without a cerebral protection filter; therapeutic success was achieved,
as these were dissection cases.
In 113 patients (97.4%), Casper stents were successfully placed in the carotid artery.
During the procedure, 1 patient (0.8%) underwent a dissection of the internal iliac
artery. One patient (0.8%) had encephalic thromboembolic complications, which were
promptly identified and treated with stenting and recanalization of the affected arterial
segment. Another patient (0.8%), who had a critical stenosis of 99%, with calcified
plaque and a kinking of the left internal carotid artery, had a rupture of the artery
in the distal portion of the stent during balloon angioplasty; this was the only case
of death during the procedure.
Postoperative Complications
In 97.4% of the cases, there were no complications after the surgical procedure (113/116).
Among the events observed, 1 patient had TIA (0.8%) and 2 had a hematoma at the puncture
site (1.6%), both treated conservatively.
There were 3 deaths, at 12, 18, and 19 days after the procedure. There was no causal
relationship between these late deaths and the endovascular intervention. This outcome
is attributed to the intrinsic complications of the initial ischemic stroke – infectious
disorders such as aspiration pneumonia and evolution toward multiple organ failure.
Restenosis Control Follow-up and Modified Rankin Scale
Throughout the clinical follow-up, a total of 115 patients (99.1%) remained stenosis-free
(< 30%) on imaging, whereas 1 patient (0.8%) had residual stenosis (between 30 and
40%). Up to the last evaluations, no patient developed carotid restenosis or device
occlusion after implantation of the Casper stent.
[Table 2] shows the mRS after 90 days of follow-up. The mean mRS value after angioplasty was
0.38, which points to the existence of reduced deficits in the functional evolution
of the studied individuals.
Table 2
Outcomes and neuroimaging
|
Characteristic
|
All cases
n = 116
|
|
Immediate procedure success (n [%])
|
115 (99.1)
|
|
Transprocedural events (n [%])
|
|
|
None
|
113 (97.4)
|
|
Dissection of the internal iliac artery
|
1 (0.8)
|
|
Thromboembolic complication
|
1 (0.8)
|
|
Vascular rupture and death
|
1 (0.8)
|
|
Technical success (n [%])
|
|
|
No stenosis (< 30%)
|
115 (99.1)
|
|
Residual stenosis (30-40%)
|
1 (0.8)
|
|
Late restenosis
|
0 (0)
|
|
Stent occlusion (n [%])
|
0 (0)
|
|
Post procedural events (n [%])
|
|
|
None
|
113 (97.4)
|
|
Minor stroke
|
1 (0.8)
|
|
Groin hematoma at the puncture site
|
2 (1.6)
|
|
mRS after 3 months (mean ± SD)
|
0.38 ± 1.23
|
|
0 (n [%])
|
105 (90.5)
|
|
1 (n [%])
|
0 (0)
|
|
2 (n [%])
|
2 (1.7)
|
|
4 (n [%])
|
6 (5.2)
|
|
5 (n [%])
|
2 (1.7)
|
|
6 (n [%])
|
1 (0.8)
|
|
Late death (n [%])
|
3 ()
|
Abbreviations: mRS, modified Rankin scale; SD, Standard deviation.
Discussion
Advances in neurointerventional techniques and the emergence of new endovascular materials
have made stent angioplasty a safe and effective alternative for the treatment of
carotid stenosis. Factors contributing to this evolution range from greater operator
experience and selection of candidates for intervention to better device design.[2] The present study reports the outcome of a case series performed in a reference
center including 116 patients with asymptomatic (4%) and symptomatic (96%) carotid
stenosis to evaluate the performance of the Casper-RX stent. As a primary endpoint,
device placement was successfully completed in 97.4% of the cases, with no immediate
intercurrences.
For a long time, arterial endarterectomy (AE) was the recommended therapy for carotid
artery stenosis.[8] Currently, carotid angioplasty is increasingly indicated. Both methods achieve the
same revascularization success rates, a similar incidence of complications and of
stroke in the short- and long-term.[9] Patients < 70 years old, as well as the symptomatic ones with severe stenosis and
comorbidities that put them at high surgical risk, seem to benefit from angioplasty
treatment.[10]
[11] The current literature still favors endarterectomy as being overall safer and more
effective.[12] However, there is still much to learn about the feasibility and safety of stent
systems used today.
A growing number of studies regarding this device supports its good performance and
promising results in selected individuals. Mutzenbach et al,,[13] in a study of 138 patients who underwent angioplasty with Casper stenting, achieved
full success in all cases, with no intraoperative technical failure or adverse neurological
events reported within 90 days. Only 14.5% of the cases had residual stenosis (between
30 and 40%) after the procedure. In the present study, were also found a high rate
of surgical success and few intraoperative complications when using Casper stents.
After 90 days of follow-up, the neurological and functional outcome was favorable
in most cases, with no deficits in 93.1% of the individuals assessed using the mRS
scale. The rate of residual stenosis in the study population was even lower (0.8%),
and no cases of late restenosis or stent occlusion were recorded, which speaks in
favor of the efficacy of the implanted device. The contribution of brain protection
filters and of antiplatelet therapy for these outcomes should be considered.
In another study, in a sample of 110 severe carotid stenosis patients, the implantation
of Casper stents combined with a distal embolic protection device was shown to be
safe and to lead to a lower rate of ischemic lesions on diffusion-weighted MRI when
compared with other stents, especially the conventional single-layer ones.[14] Similarly, a reduced number of thromboembolic complications was observed in this
study. During stent implantation, there was only one thromboembolic event, which was
promptly reversed and did not cause any permanent neurological deficits. Throughout
the follow-up of up to 6 months after the procedure, there was one case of TIA. Such
an outcome may be attributed to the double nitinol layer and micro mesh, as well as
to the closed-cell design, of the Casper stent.[4] The other complications – late deaths, vascular rupture, internal iliac artery dissection,
and puncture site hematoma – were not related to the device itself, but rather to
the inherent risk of the procedure and to the underlying diseases of the patient.
In a study with a smaller sample size, Ozpeynirci et al.[15] analyzed 29 patients who underwent ICA angioplasty using a Casper-RX stent, of whom
78.6% were male with a mean age was 71.7 years old. The authors report 6 adverse events
in the perioperative period, including 1 stent occlusion (3.4%), 2 patients with type
2 parenchymal hematoma (6.8%), and 3 other patients (10.3%) with a massive cerebral
infarction area not related to a worse prognosis or to stent occlusion. No thromboembolic
events were observed intraoperatively.
Conclusion
The outcomes achieved in the present study corroborate the efficacy and safety of
the use of Casper-RX stents to treat ICA stenosis, as previously demonstrated in the
literature. In this series, technical success was achieved, with good clinical repercussion
and a low complication rate, considering the sample size. However, long-term follow-up
is needed to better evaluate this new device, as well as comparative studies with
other closed-cell stents.
