Circulation. 2006;114:e1-e4
doi: 10.1161/CIRCULATIONAHA.106.624379
(Circulation. 2006;114:e1-e4.)
© 2006 American Heart Association, Inc.
Carotid Stenting
Marco Roffi, MD;
Jay S. Yadav, MD
From the Department of Cardiology, University Hospital, Zurich, Switzerland (M.R.), and the Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, Ohio (J.S.Y.).
Correspondence to Jay S. Yadav, MD, Cleveland Clinic Foundation, Department of Cardiovascular Medicine, F25 9500 Euclid Ave, Cleveland, OH 44195. E-mail yadavj{at}ccf.org
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Introduction
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In Western countries, stroke is the third leading cause of death,
after heart disease and cancer, and is the most common cause
of permanent disability.
1 This neurological condition affects
&0.2% of the population each year, and the incidence of
stroke-related death is expected to double over the next 30
years. The estimated direct and indirect costs of stroke in
the United States for the year 2006 are estimated to be $58
billion.
1 A stenosis of the internal carotid artery may be responsible
for 10% to 20% of all strokes or transient ischemic attacks.
Carotid artery stenting (CAS) has emerged as a potential alternative
revascularization strategy to carotid endarterectomy (CEA) for
patients with carotid stenosis.
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Case Presentation
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A 75-year-old man known to have an asymptomatic occlusion of
the left internal carotid artery presented with transient left
arm weakness. His cardiovascular risk factors included smoking
and hyperlipidemia. Because of poor compliance, the patient
was on no medication at the time of admission. Urgent computed
tomography scan of the brain showed no bleeding or ischemic
lesions. Same-day carotid Duplex ultrasound demonstrated a
70%
stenosis of the right and the previously diagnosed chronic occlusion
of the left internal carotid arteries. Aspirin and a statin
were administered, and revascularization options were discussed
with the patient.
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Carotid Endarterectomy
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Large-scale randomized clinical trials have established the
superiority of CEA over medical management in preventing neurological
events in patients with high-grade carotid stenosis. A pooled
analysis of the randomized data showed that surgery was highly
beneficial for individuals with symptomatic stenosis
70% and
of some benefit for those with 50% to 69% stenosis.
2 In asymptomatic
patients, surgery has been associated with a small but definite
reduction in the risk of stroke in the presence of a stenosis
60%.
3 The American Heart Association guidelines support CEA
for all symptomatic patients with
50% internal carotid artery
stenosis and for asymptomatic patients with stenosis
60%, as
long as the estimated perioperative death or stroke rate is
<3% and life expectancy is
5 years.
4 For individuals with
surgical risk up to 5%, CEA is considered an acceptable but
not proven therapy for stenosis
75%.
The excellent surgical outcomes achieved in randomized trials are frequently considered the benchmark for CAS. These results, however, were obtained by high-volume surgeons treating low-risk patients and may not be reproduced in clinical practice. Accordingly, an analysis on >110 000 Medicare beneficiaries showed that although within randomized trials, the perioperative mortality rate for CEA was as low as 0.6% for symptomatic and 0.1% for asymptomatic patients, the overall perioperative mortality rate in the hospitals participating in the trials was 1.4%.5 In addition, the study detected a perioperative mortality rate of 2.5% in low-volume hospitals. Although low operator and hospital volumes are factors that have been repeatedly associated with poor outcomes after CEA, most surgeries are performed in the United States by low-volume surgeons. An analysis that included >136 000 CEAs documented a mean volume per operator of 15 procedures per year, whereas one third of the patients were operated on by surgeons with a mean CEA volume of 5 per year.6 With respect to patient selection, the impact of comorbidities on the outcomes of CEA is recognized. High-risk features, according to the Centers for Medicare and Medicaid Services (CMS), are listed in Table 1, and the advantages and disadvantages of CEA are reported in Table 2.
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Carotid Stenting
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Percutaneous carotid revascularization with balloon angioplasty
was pioneered in the early 1980s. The advent of stent technology
in the mid 1990s allowed protection against dissections and
a restenosis rate in the single-digit range. Although prospective
comparative studies are lacking, stenting has been virtually
uniformly embraced as superior to angioplasty in this setting.
The introduction of embolic protection devices (EPDs) in the
year 2000 made CAS a safer procedure (
Figure 1). The need for
EPDs came from transcranial Doppler observations that embolization,
although in most cases clinically silent, occurred in virtually
all cases of both surgical and endovascular carotid revascularization.
A broadly shared opinion, although not unanimous, supports the
use of EPDs during CAS, despite the lack of randomized data.
A systematic review of 2357 patients who underwent CAS without
EPD and 839 protected procedures documented 30-day death and
stroke rates of 5.5% and 1.8% (
P<0.001), respectively.
7 Similarly,
in a worldwide registry of >10 000 CAS procedures, the use
of EPDs halved the event rates.
8 As a possible confounding factor,
the use of an EPD likely occurred at a later stage of the operator’s
learning curve. Advantages and disadvantages of CAS are listed
in
Table 2.
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Figure 1. EPDs. The most widely used type is the filter (top), which allows blood flow and optimal lesion visualization throughout the procedure. Alternative devices include proximal balloon occlusion (middle) and distal balloon occlusion (bottom).
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Decision Making in Carotid Revascularization
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Low-Risk Patients
The Carotid and Vertebral Artery Transluminal Angioplasty Study
(CAVATAS) compared CEA and carotid angioplasty in patients at
low to moderate risk for surgery.
9 A total of 504 patients with
symptomatic carotid stenosis were randomized to CEA or angioplasty.
9 The incidence of death or stroke at 30 days was 10% in the endovascular
group and 9.9% in the surgical group. The outcomes among the
2 groups remained comparable at 3 years. The study was criticized
by the interventionalist community for the low stenting rate
(26%) and by surgeons for the high event rates in the surgical
arm. Currently, several randomized trials are underway that
compare CAS and CEA in low-risk patients, including the US National
Institutes of Health–sponsored Carotid Revascularization
Endarterectomy Versus Stent Trial (CREST). Until these results
become available, low-risk patients should be treated with CAS
only within studies.
High-Risk Patients
The Stenting and Angioplasty With Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial is the first and currently only randomized trial comparing CEA and CAS with EPD.10 The study focused on patients at high risk for surgery with 50% symptomatic or 80% asymptomatic carotid stenosis. Among the 334 patients randomized, major adverse events occurred in 12.2% in the stent group and in 20.1% in the CEA group (P=0.053) at 1 year (Figure 2). In addition, the need for repeat carotid revascularization was lower in the CAS group than in the CEA group (0.6% versus 4.3%; P=0.04). For the first time, nonfatal cardiac events were included in the outcome analysis of a carotid revascularization trial. Patients who underwent CAS had significantly fewer myocardial infarctions at 30 days compared with those who were randomized to CEA (1.9% versus 6.6%; P=0.04). Prospective registries including almost 4000 protected CAS procedures, performed mainly in high-risk patients, resulted in 30-day death, myocardial infarction, or stroke rates ranging between 3.4% and 7.8%.11 On the basis of the current evidence, CAS with EPD in the hands of experienced operators should be considered equal if not superior to CEA in this patient population.
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Figure 2. One-year results of the SAPPHIRE trial. Major adverse events were defined as composite of death, stroke, or myocardial infarction within 30 days or death or ipsilateral stroke between 31 days and 1 year. In the intention-to-treat analysis (A), the rate of event-free survival at 1 year was 87.8% among patients randomly assigned to CAS versus 79.9% among those randomly assigned to CEA (P=0.053). In the actual-treatment analysis (B), the rate of event-free survival at 1 year was 88.0% among patients who received a stent versus 79.9% among those who underwent CEA (P=0.048). I bars represent 1.5 times the standard error. Reproduced from Yadav et al,10 with permission from the Massachusetts Medical Society.
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Current CMS Guidelines
In the United States, the CMS has concluded that CAS with EPD is reasonable and appropriate for symptomatic patients with carotid stenosis 70% at high risk for surgery (Table 1).12 If performed within clinical trials or CAS postapproval studies, the procedure may be performed in high-risk symptomatic patients with 50% to 70% stenosis and in high-risk asymptomatic individuals with stenosis 80%. Carotid stenting is considered appropriate if performed in facilities and by operators complying with the set standards.12 A suggested management strategy for patients with carotid stenosis is illustrated in Figure 3.
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Figure 3. Management strategy for patients with carotid stenosis. LDL indicates low-density lipoprotein; MR, magnetic resonance; and CT, computed tomography.
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Conclusions
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CAS has emerged as alternative treatment to CEA in patients
with carotid stenosis. Current evidence suggests that using
an EPD markedly reduces the number of neurological events. In
patients at high risk for surgery, the SAPPHIRE trial has shown
that protected CAS is equal if not superior to surgery in the
hands of experienced operators. Ongoing randomized trials, including
CREST, are investigating the role of CAS in low-risk patients.
In the United States, CMS guidelines currently support protected
CAS for patients at high risk for surgery with symptomatic carotid
stenosis
70%. Because of the presence of a contralateral carotid
occlusion, the patient discussed earlier was considered at high
risk for surgery. He was offered both CEA and CAS but preferred
the endovascular approach. After clopidogrel loading, he underwent
uneventful protected CAS of the right internal carotid artery.
At the 1-year follow-up, he was free of recurrent neurological
events and restenosis.
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Acknowledgments
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Disclosures
None.
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References
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- Heart Disease and Stroke Statistics–2006 Update. Dallas, Tex: American Heart Association; 2006.
- Rothwell PM, Eliasziw M, Gutnikov SA, Fox AJ, Taylor DW, Mayberg MR, Warlow CP, Barnett HJ. Analysis of pooled data from the randomised controlled trials of endarterectomy for symptomatic carotid stenosis. Lancet. 2003; 361: 107–116.[CrossRef][Medline]
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- Rothwell PM, Goldstein LB. Carotid endarterectomy for asymptomatic carotid stenosis: asymptomatic carotid surgery trial. Stroke. 2004; 35: 2425–2427.[Free Full Text]
- Biller J, Feinberg WM, Castaldo JE, Whittemore AD, Harbaugh RE, Dempsey RJ, Caplan LR, Kresowik TF, Matchar DB, Toole JF, Easton JD, Adams HP Jr, Brass LM, Hobson RW 2nd, Brott TG, Sternau L. Guidelines for carotid endarterectomy: a statement for healthcare professionals from a Special Writing Group of the Stroke Council, American Heart Association. Circulation. 1998; 97: 501–509.[Free Full Text]
- Wennberg DE, Lucas FL, Birkmeyer JD, Bredenberg CE, Fisher ES. Variation in carotid endarterectomy mortality in the Medicare population: trial hospitals, volume, and patient characteristics. JAMA. 1998; 279: 1278–1281.[Abstract/Free Full Text]
- Birkmeyer JD, Stukel TA, Siewers AE, Goodney PP, Wennberg DE, Lucas FL. Surgeon volume and operative mortality in the United States. N Engl J Med. 2003; 349: 2117–2127.[Abstract/Free Full Text]
- Kastrup A, Groschel K, Krapf H, Brehm BR, Dichgans J, Schulz JB. Early outcome of carotid angioplasty and stenting with and without cerebral protection devices: a systematic review of the literature. Stroke. 2003; 34: 813–819.[Abstract/Free Full Text]
- Wholey MH, Al-Mubarek N. Updated review of the global carotid artery stent registry. Catheter Cardiovasc Interv. 2003; 60: 259–266.[CrossRef][Medline]
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- Endovascular versus surgical treatment in patients with carotid stenosis in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS): a randomised trial. Lancet. 2001; 357: 1729–1737.[CrossRef][Medline]
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- Yadav JS, Wholey MH, Kuntz RE, Fayad P, Katzen BT, Mishkel GJ, Bajwa TK, Whitlow P, Strickman NE, Jaff MR, Popma JJ, Snead DB, Cutlip DE, Firth BG, Ouriel K. Protected carotid-artery stenting versus endarterectomy in high-risk patients. N Engl J Med. 2004; 351: 1493–1501.[Abstract/Free Full Text]
- Wholey MH. History and current status of endovascular management for the extracranial carotid and supra-aortic vessels. J Endovasc Ther. 2004; 11 (suppl 2): II-43–II-61.[Medline]
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- CMS decision memo for carotid artery stenting (CAG-00085R). Available at: http://www.cms.hhs.gov/mcd/viewdecisionmemo.asp?id=157. Accessed December 12, 2005.
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Issue Highlights
Circulation 2006 114: 1.
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Introduction
Case Presentation