Long-Term Follow-Up of Patients After Carotid Stenting With or Without Distal Protective Device in a Single Tertiary Medical Center

Abstract

Objective: To evaluate the immediate and long-term clinical outcomes after carotid artery stenting (CAS) with and without protection devices (PDs), compared with carotid endarterectomy (CEA). Methods: A total of 116 patients with symptomatic carotid stenosis underwent CAS; 56 patients (48.3%) underwent CAS-PD; and 137 patients underwent CEA. Results: There were more ipsilateral transient ischemic attacks (TIAs) in the CEA group than in CAS-PD and CAS + PD (4 [3%] vs 1 [1.6%] and 0 respectively, P = 0.02). In the CAS-PD group there were more vertebrobasilar TIAs, ipsi- and contralateral strokes, myocardial infarctions, and death rates in the 30-day postprocedural period. After 8-year follow-up, there were 18 (30%) death cases in the CAS-PD group, 10 death cases (17%) in the CAS + PD patients, and 15 death cases (11%) in the CEA group of patients (P = .02). Conclusion: Our data show that CAS + PD was associated with lower rate of vascular complications and mortality compared with CAS-PD and CEA.

Keywords

stroke carotid stenosis carotid endarterectomy carotid artery stenting protection devices cerebral embolism

Introduction

Carotid artery occlusive disease is responsible for approximately 20% of ischemic strokes (ISs), and carotid endarterectomy (CEA) is considered to be the “gold standard” treatment.^1–3 Carotid artery stenting (CAS) is becoming an alternative to CEA method for treating carotid artery occlusive disease.^4
–6 However, the risk of brain ischemic lesions associated with distal embolization during CAS remains a major concern.^7
–9 Protection devices (PDs), which retain particles and debris that may be generated and separated from the vessel wall during CAS, potentially reduce the risk of neurological complications. Several types of PDs have been developed and are currently classified into three main categories: distal balloon occlusion, distal filtration and proximal occlusion.¹⁰ The SAPPHIRE (Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy) trial, the first controlled randomized trial of CAS using PDs, suggested that CAS using PDs was not inferior to CEA and has a lower incidence of 30 days of adverse clinical events compared with CEA.¹¹ Multicenter feasibility trial of CAS with or without PDs has shown that the use of PDs might reduce the risk of postprocedural major ipsilateral strokes.¹² Nevertheless, PDs have the potential to produce separate complications such as vasospasms or dissections associated with temporary or permanent carotid occlusion.¹³ Therefore, the safety and cost aspects of CAS with or without PDs are still disputable. The recent analysis of data from SPACE (Stent-Protected Angioplasty versus Carotid Endarterectomy) trial does not support the need for a PD in CAS.¹⁴ In this regard, it is important to evaluate late outcomes of CAS with PDs and to compare their clinical benefit with CAS without PDs and CEA. Previously, we reported our results on 5 years of clinical experience with CAS.¹⁵ We now present data on immediate (30 days) and late (8 years) outcomes after CAS with and without PDs compared with CEAs.

Patients and Methods

Patients

Between July 1999 and July 2007, 116 consecutive patients underwent CAS in Assaf Harofeh Medical Center. Our study was divided into 2 major parts. In the first part, 56 patients (45 males and 11 females) underwent CAS without PD. In the second part, in 60 patients (46 males and 14 females) CAS procedures were performed with distal PD.

All patients presented with a significant (≥70%) stenosis of the internal carotid artery (ICA) or common carotid artery (CCA). The degree of carotid artery stenosis was calculated based on the North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria by Carotid Doppler ultrasound or angiography.¹⁶ Most patients who underwent treatment with CAS were considered to be at high risk for CEA. High risk was defined as patients having one or more of the following anatomic characteristics: (1) restenosis after previous CEA, (2) lesion located above C2 or below the clavicle, (3) previous radical neck dissection, (4) radiation therapy, (5) presence of a permanent tracheostomy, (6) frozen neck, (7) tandem lesions within the same carotid artery or contralateral ICA occlusion, (8) classification III or IV angina or congestive heart failure, (9) severe chronic obstructive pulmonary disease, and (10) cardiac disease necessitating open heart surgery within 4 weeks. Patients were excluded if they had a major neurological deficit or any other illness, impending informed consent, severe renal insufficiency (serum creatinine >3 mg/dL), peripheral vascular disease precluding femoral artery access, or the presence of severe disability due to previous stroke or dementia. Patient selection for CAS was determined by a multidisciplinary stroke team including a cardiologist, a radiologist, a neurologist, and vascular surgeons. The operator (A.P.) informed patients about the proven efficacy of CAS in randomized trials and offered them this treatment as alternative to CEA. The operator (A.P.) was credentialed to perform CAS procedure by Assaf Harofeh Medical Center with high experience level ranking. Written informed consent was obtained from all the patients before the procedure.

Patients were eligible for CEA if they had symptomatic carotid artery disease and severe (more than 70% diameter) stenosis of the ICA, according to NASCET criteria, and had not contraindications mentioned above. In all, 137 consecutive patients (83 males and 54 females) who underwent CEA procedures were followed up in order to compare their outcomes with CAS patients.

Patient selection was determined by a multidisciplinary stroke team (cardiologist, radiologist, neurologist, and vascular surgeon).

Technique

Access to the carotid vessels was achieved through standard femoral artery puncture. Prior to intervention, angiograms of aortic arch and carotid arteries (both extra and intra cranial) were obtained.

All patients received 5000 units of heparin at the beginning of the procedure. Our preferred sheath was the 6F Cook Shuttle Select Slip Catheter (KSAS—60-38-90-RB-SHTL-FLEX-HL-Cook, Bloomington, Indiana). This glide sheath is unique in being kink resistant and also accepting 2 types of diagnostic 6.5F catheters (SCRB 6.5-3.5-125-P-NS-SIM2/H1-SHTL by Cook). These slip catheters were used in difficult anatomy, when extra support was needed to advance the sheath into the CCA. The sheath was advanced into the CCA over a stiffer 0.035 guidewire (Emerald, Cordis Europa N.V., Rodeu, The Netherlands), which was placed either in the external carotid or in the proximal CCA.

Two types of carotid stents were used: the SMART 6-40 (Cordis, Europa, N.V.), which was used in the first 60 cases, and the Sinus-Carotid-Conicall Rx 6m-9m-40mm (Optimed Ettingen, Germany). All stents were deployed from the ICA to the CCA.

In the first 60 cases, no PD was used, because all CAS procedures were done with the 7 mm Angioguard Rx PD (Cordis Europa N.V.). The Angioguard Rx PD is a 0.014 guidewire with the addition of a filter basket at the distal end. The basket consists of a thin porous membrane supported by a metal skeleton (Nitinol) which enables it to have a very low profile when closed. We routinely use the 7 mm size which is recommended for vessel diameter of 5.5 to 6.5 mm. The PD was anchored at the C1-C2 position in cases with very tight ICA stenosis; predilatation with a 4 mm balloon catheter (Aviator plus Rx-Cordis Europe N.V.) was performed after a intravenous (IV) bolus of 0.5 to 1.0 mg atropine. This preliminary angioplasty was performed in order to avoid dissection by the stent system.

After the stents were deployed, a final angioplasty with a 6 mm balloon (Aviator plus Cordis Europa N.V.) was performed, again after a IV bolus of 0.5 to 1.0 mg atropine.

The PD was removed and a final angiogram obtained in case spasm of the distal ICA was seen (due to the PD); intra-arterial nitroglycerin 200 to 400 mg was given and a second run of the ICA performed. The long sheath was exchanged for an 11-cm 6F sheath and the patient was transferred to the intensive coronary care unit (ICCU) for observation, before returning to the vascular department.

Patients treated for ICA stricture post CAS were sent directly to the vascular department, since no carotid body complications were noted.

All patients received 600 mg clopidogrel prior to the procedure and another bolus of 450 to 600 mg post CAS.

All patients were encouraged not to take their antihypertensive drugs at the day of procedure.

Neurologic Evaluation and Patient Follow-Up

Within 24 hours after CAS, each patient was examined by the board-certified neurologist who also had evaluated the patient before the intervention. Careful neurological examination and National Institute of Health Stroke Scale (NIHSS) was assessed in all patients.¹⁷ A transient ischemic attack (TIA) was defined as a focal retinal or hemispheric event from which the patient made complete recovery within 24 hours. A minor nonfatal IS was defined as a new neurological deficit that either resolved completely within 30 days or increased the NIHSS by ≤3. A major nonfatal IS was defined as a new neurological deficit that persisted >30 days and increased the NIHSS by ≥4. Any neurologic change was recorded. Long-term outcomes are reported as neurological events and deaths. A fatal stroke was defined as death attributed to an IS or intracerebral hemorrhage and did not include brain tumors or death resulting from head trauma.

Clinical follow-up (mean ± standard deviation [SD], 84 ± 12 months) was available for all patients who survived the periprocedural period. Follow-up phone interviews or observation in outpatient clinic were conducted at 1 month, at 6 months, and at yearly intervals thereafter by a dedicated research coordinator or physician. Patients were instructed to notify the coordinator if symptoms suggestive of a neurological event occurred. When a neurological event occurred, CT of the head was performed, and the physician was contacted to accurately document the episode. Hospital discharge diagnoses were also reviewed to adjudicate events. When a death occurred, the cause of death was obtained from the death certificate or medical reports All information were recorded as prospectively maintained database.

Statistics

Categorical data, the incidence of clinically apparent neurological complications, and mortality rates in the 2 groups of CAS patients (with or without PDs) and group of CEA were compared using analysis of variance (ANOVA). The comparison between CAS + PD, CAS-PD, and CEA groups during 8 years of follow-up in terms of cumulative end point events (all strokes/death) was analyzed by Kaplan-Meier methods and a long rank statistics. For all the tests in this study, the P values <.05 were considered significant. All the statistical analyses were performed using the SPSS software program (SPSS 10.0; SPSS, Chicago, Illinois).

Results

The baseline characteristics of all the patients are shown in Table 1. Three groups were comparable in terms of major vascular risk factors (hypertension, diabetes mellitus, smoking, hyperlipidemia, and previous strokes or TIAs).

Table 1.

Baseline Characteristics

	CAS-PD (N = 56)		CAS + PD (N = 60)		CEA (N = 137)		P Value
Mean age ±SD), years	69 ± 8.54		68 ± 5.9		68 ± 9.2		NS
Female, n (%)	11	20%	14	23%	35	26%	NS
CAD (AP, CABG, MI, PTCA), n (%)	43	77%	38	63%	51	37%	.05
Hypertension, n (%)	43	77%	48	80%	83	61%	NS
Diabetes, n (%)	28	49%	30	50%	55	40%	NS
Hyperlipidemia, n(%)	28	49%	33	55%	60	44%	NS
Current smoker / past smoker, n(%)	18	32%	12	20%	54	39%	NS
Stroke /TIA, n (%)	60	100%	60	100%	137	100%	NS
Bilateral carotid disease, n (%)	48	86%	44	73%	71	52%	.02
Contralateral occlusion, n (%)	9	16%	7	12%	18	13%	NS
Prior ipsilateral CEA, restenosis, n (%)	11	20%	6	10%	0	0%	.01
Prior neck surgery/radiation, n(%)	8	14%	3	5%	0	0%	.01

Abbreviations: CAS-PD, carotid artery stent without protective device; CAS + PD, carotid stent with protective device; CEA, carotid endarterectomy; TIA, transient ischemic attack; CAD, coronary artery disease; AP, angina pectoris; MI, myocardial infarction; CABG, coronary artery bypass grafting; PTCA, percutaneous transluminal coronary angioplasty; NS, nonsignificant.

Intraprocedural complications included cerebrovascular events in 2 (3%) CAS-PD patients, 1 (2%) CAS+ PD patients, and 1 (1%) CEA patient; hemodynamic changes in 11 (18%) CAS-PD patients, 19 (32%) CAS + PD patients, and 12 (9%) CEA patients; and procedural failure in 4 (6.6%) CAS-PD patients, 5 (8%) CAS + PD patients, and 2 (1%) CEA patients. Vocal cord paralysis (7.5%), hypoglossal nerve injury (4.3%), hyperperfusion (6.4%), dysphagia (3.2%), and dyspnea (1.1%)were noticed only during the CEA procedures.

Thirty-day outcome data are listed in Table 2. There were significantly more ipsilateral TIAs in the CEA group than in CAS-PD, CAS + PD (3% vs 1.6% and 0%, respectively, P = .02). However, in the CAS-PD group there were significantly more vertebrobasilar TIAs, ipsi- and contralateral strokes, myocardial infarctions, and death rates after the 30-day postprocedural period.

Table 2.

Thirty-Day Outcomes

	CAS-PD N = 56		CAS + PD N = 60		CEA N = 137		P Value
	n	%	n	%	n	%	P Value
TIA ipsilateral, n (%)	1	1.6	0	0	4	3	.02
TIA VB, n (%)	2	3.3	1	1.7	0	0	.02
Stroke ipsilateral, n (%)	5	8.3	1	1.7	2	1.4	.001
Stroke contralateral, n (%)	1	1.6	0	0	0	0	.05
Transient confusion, n (%)	2	3.3	1	1.7	1	1	.04
Stent thrombosis, n (%)	2	3.3	1	1.7			.05
Myocardial infarction, n (%)	1	1.6	0	0	0	0	.001
Death, n (%)	2	3.3	0	0	2	1.4	.05

Abbreviations: TIA, transient ischemic attack; VB, vertebrobasilar.

After 8 years of follow-up, there were 8 (14%) ISs (3 ipsilateral, 2 contralateral, and 3 vertebrobasilar) and 4 (7%) restenosis in the CAS-PD group of patients; 4 (6.5%) ISs (1 ipsilateral, 2 contralateral, and 1 vertebrobasilar) and 2 (3.3%) restenosis in the CAS + PD group, 24 ISs (7 ipsilateral, 9 contralateral, and 4 vertebrobasilar) and 8 (5.8%) restenosis in the CEA group. There were 18 (30%) death cases in the CAS-PD group of patients (1 due to fatal stroke), 10 death cases (17%) in the CAS + PD patients (1 due to fatal stroke) and 15 death cases (11%) in the CEA group of patients (2 cases due to fatal stroke; P = 0.02). Eight years of follow-up free survival cumulative event (all strokes/death) rates between CAS + PD, CAS-PD, and CEA patients are presented in Figure 1. Kaplan-Meier curves showed significantly higher freedom from end point events in CAS + PD, P = .04.

Discussion

Our data show that CAS + PDs is associated with lower rate of vascular complications in the immediate (30-day) and long-term (8 years) compared with CAS-PD and CEA patients.

Carotid artery stenting, as opposed to CEA, was primarily conceptualized and devised as a minimally invasive procedure to treat carotid disease. The main limitation of CAS is the risk of distal cerebral embolization. Protection devices, first devised in 1990, have the ability to retain particles generated during the procedure and has been proposed to reduce the frequency of emboli-related stroke during CAS.¹⁸ Several nonrandomized studies have shown the safety and possible efficacy of PDs.^19–21 More recently, PDs became mandatory in most large prospective, randomized studies comparing CEA with CAS including SAPPHIRE and EVA-3S (Endarterectomy Versus Angioplasty in Patients With Symptomatic Severe Carotid Stenosis).¹¹ ^,22 In SPACE and CREST (Carotid Revascularization Endarterectomy vs Stenting Trial), PDs were used in 27% and 96% of the patients, respectively.¹⁴ ^,23 Only CAVATAS (Carotid and Vertebral Artery Transluminal Angioplasty Study) was performed without PDs and in ISCC (International Carotid Stenting Study) PDs were not mandatory.^24,25 However, all PDs are not equivalent and may have drawbacks. Moreover, since their application may result in additional complications, the routine use of PDs is still controversial; and no consensus, neither level 1 evidence of benefit, has emerged.

Several factors limit the efficacy of PDs. Among them is the need to cross the plaque before protection is achieved. Another limitation is the stiffness of the devices, which makes navigation through the stenosis challenging, especially in the presence of tortuosity, commonly present in patients with arteriosclerosis.²⁶

Nevertheless, some authors claim that the routine use of PDs is beneficial, leading to a 60% reduction of brain embolisms.²⁷ Moreover, in consecutive series of CAS, the PD use reduced the emboli-related acute neurological event rate by 79%.²⁸ Similar results in favor or proving the noninferiority of PDs were shown in several other studies.^29–31 On the other hand, in a recently published retrospective study,²⁶ no significant differences in the incidence of perioperative stroke, myocardial infarction (MI), and death rates between patients treated with or without PDs were found. There was a slightly higher incidence of perioperative strokes in the nonprotected group, which did not reach statistical significance. In a subanalysis of pooled data from Pro-CAS, a prospective, multicenter registry of CAS, the use of a protection system did not influence the risk of periprocedural stroke or death.³²

Surprisingly, use of filter-type protection was associated with an increase in new lesions on diffusion-weighted magnetic resonance imaging (DWI) of the brain and significantly higher rates of total and particulate microembolization on transcranial Doppler ultrasonography (TCD) than unprotected CAS. That study, however, did not include clinical end points.³³

In line with some of the recent experience, our observation provides robust data that PD can be performed safely with high long-term success rate, supporting the routine use of PDs during CAS.

Nonetheless, it should be kept in mind that carotid stenosis is a heterogeneous entity that encompasses different pathological conditions. Therefore, the type of intervention should be tailor made for each case individually, preferably by a multidiscipliner team including neurologist, vascular surgeon, and interventional radiologist, taking into account various anatomical and clinical considerations.

The present study has several limitations: This is a single-center study with relatively small cohort that does not necessarily represent the entire spectrum of carotid interventions; the procedure was done by with operators having different experiences and backgrounds. We also did not evaluate the impact of carotid plaque morphology on outcome. The strength of the study is that it includes consecutive nonselected patients and encompasses neurological evaluation by stroke experts.

Conclusions

Our results demonstrate reduced long-term mortality associated with the use of CAS + PDs, supporting the assertion that PDs should become an integral part of CAS. Notably, since CAS + PDs is a relatively a new modality, it could be argued that with increased experience and improved technology the results of CAS + PDs may even improve in the future. Nonetheless, there is a need for a well-designed, multicenter, randomized, prospective study to determine the value of distal protection in CAS. Since the embolic stroke rate during CAS is low, this randomized trial would require a large cohort or alternatively the use of imaging modalities (TCD, DWI) to detect silent microemboli, in order to conclusively confirm or dismiss our conclusions.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

References

Moore

Barnett

Beebe

. Guidelines for carotid endarterectomy. A multidisciplinary consensus statement from the Ad Hoc Committee, American Heart Association. Circulation. 1995;91(2):566–579.

Rosamond

Flegal

Friday

. Heart disease and stroke statistics-2007 update: a report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Circulation. 2007;115(5):e69–e171.

Barnett

Taylor

Eliasziw

. Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med. 1998;339(20):1415–1425.

Meyers

Schumacher

Higashida

Leary

Caplan

. Use of stents to treat extracranial cerebrovascular disease. Annu Rev Med. 2006;57:437–454.

Biggs

Moore

. Current trends in managing carotid artery disease. Surg Clin North Am. 2007;87(5):995–1016.

Vijungco

Eskandari

. New treatments for cerebrovascular disease. Perspect Vasc Surg Endovasc Ther. 2005;17(4):279–287.

Goodney

Schemerhone

Powell

. Current status of carotid stenting. J Vasc Surg. 2006;43(2):406–411.

van Heesewijk

Vos

Louwerse

. Carotid PTA and Stenting Collaborative Research Group. New brain lesions at MR imaging after carotid angioplasty and stent placement. Radiology. 2002;224(2):361–365.

Al-Mubarak

Roubin

Vitek

Iyer

New

Leon

. Effect of the distal-balloon protection system on microembolization during carotid stenting. Circulation. 2001;104(17):1999–2002.

10.

Eskandari

. Design and development of mechanical embolic protection devices. Expert Rev Med Devices. 2006;3(3):387–393.

11.

Gurm

Yadav

Fayad

. SAPPHIRE investigators. Long-term results of carotid stenting versus endarterectomy in high-risk patients. N Engl J Med. 2008;358(15):1572–1579.

12.

Ouriel

Wholey

Fayad

. Feasibility trial of carotid stenting with and without an embolus protection device. J Endovasc Ther. 2005;12(5):525–537.

13.

Kim

Roh

Jeon

. Cerebral ischemia detected with diffusion-weighted MR imaging after protected carotid artery stenting: comparison of distal balloon and filter device. Korean J Radiol. 2007;8(4):276–285.

14.

Eckstein

Ringleb

Allenberg

. Results of the Stent-Protected Angioplasty versus Carotid Endarterectomy (SPACE) study to treat symptomatic stenoses at 2 years: a multinational, prospective, randomised trial. Lancet Neurol. 2008;7(10):893–902.

15.

Kimiagar

Klein

Rabey

. Carotid artery stenting in high risk patients with carotid artery stenosis not eligible for endarterectomy: clinical outcome after 5 years. Isr Med Assoc J. 2008;10(2):121–124.

16.

Staikov

Nedeltchev

Arnold

. Duplex sonographic criteria for measuring carotid stenosis. J Clin Ultrasound. 2002;30(5):275–281.

17.

Wityk

Pessin

Kaplan

Caplan

. Serial assessment of acute stroke using the NIH Stroke Scale. Stroke. 1994;25(2):362–365.

18.

Theron

Courtheoux

Alachkar

Bouvard

Maiza

. New triple coaxial catheter system for carotid angioplasty with cerebral protection. AJNR Am J Neuroradiol. 1990;11(5):869–874.

19.

Henry

Amor

Klonaris

. Angioplasty and stenting of the extracranial carotid arteries. Tex Heart Inst J. 2000;27(2):150–158.

20.

Reimers

Corvaja

Moshiri

. Cerebral protection with filter devices during carotid artery stenting. Circulation. 2001;104(1):12–15.

21.

Ohki

Veith

Grenell

. Initial experience with cerebral protection devices to prevent embolization during carotid artery stenting. J Vasc Surg. 2002;36(6):1175–1185.

22.

Mas

Chatellier

Beyssen

EVA-3S

Investigators

. Carotid angioplasty and stenting with and without cerebral protection: clinical alert from the Endarterectomy Versus Angioplasty in Patients With Symptomatic Severe Carotid Stenosis (EVA-3S) trial. Stroke. 2004;35(1):e18–e20.

23.

Sheffet

Roubin

Howard

. Design of the Carotid Revascularization Endarterectomy vs. Stenting Trial (CREST). Int J Stroke. 2010;5(1):40–46.

24.

Coward

McCabe

Ederle

Featherstone

Clifton

Brown

MM;

CAVATAS

Investigators

. Long-term outcome after angioplasty and stenting for symptomatic vertebral artery stenosis compared with medical treatment in the Carotid And Vertebral Artery Transluminal Angioplasty Study (CAVATAS): a randomized trial. Stroke. 2007;38(5):1526–1530.

25.

Featherstone

Brown

Coward

LJ;

ICSS

Investigators

. International carotid stenting study: protocol for a randomised clinical trial comparing carotid stenting with endarterectomy in symptomatic carotid artery stenosis. Cerebrovasc Dis. 2004;18(1):69–74.

26.

Tallarita

Rabinstein

Cloft

. Are distal protection devices "protective" during carotid angioplasty and stenting? Stroke. 2011;42(7):1962–1966.

27.

Henry

Polydorou

Henry

Polydorou

Hugel

. Carotid angioplasty and stenting under protection: advantages and drawbacks. Expert Rev Med Devices. 2008;5(5):591–603.

28.

Castriota

Cremonesi

Manetti

. Impact of cerebral protection devices on early outcome of carotid stenting. J Endovasc Ther. 2002;9(6):786–792.

29.

White

Iyer

Hopkins

Katzen

Russell

; BEACH Trial Investigators. Carotid stenting with distal protection in high surgical risk patients: the BEACH trial 30 day results. Catheter Cardiovasc Interv. 2006;67(4):503–512.

30.

Simonetti

Gandini

Versaci

. Carotid artery stenting: findings based on 8 years' experience. Radiol Med. 2009;114(1):95–110.

31.

Eskandari

Usman

Garcia-Toca

. Eight-year institutional review of carotid artery stenting. J Vasc Surg. 2010;51(5):1145–1151.

32.

Theiss

Hermanek

Mathias

. German Society of Angiology/Vascular Medicine; German Society of Radiology. Predictors of death and stroke after carotid angioplasty and stenting: a subgroup analysis of the Pro-CAS data. Stroke. 2008;39(8):2325–2330.

33.

Macdonald

Evans

Griffiths

. Filter-protected versus unprotected carotid artery stenting: a randomized trial. Cerebrovasc Dis. 2010;29(3):282–289.