doi: 10.1161/01.STR.0000033490.22193.1A
(Stroke. 2002;33:2520.)
© 2002 American Heart Association, Inc.
Controversies in Stroke |
Angioplasty and Stenting Should Not Be Restricted to Clinical Trials
From Lenox Hill Heart and Vascular Institute of New York, NY.
Correspondence to Gary S. Roubin, Lenox Hill Heart and Vascular Institute of New York, 130 East 77th St, New York, NY 10021. E-mail groubin{at}lenoxhill.net
Key Words: carotid endarterectomy • clinical trials • outcome • stents
Excellence in clinical practice necessitates the application of evidence-based medical decision-making in determining patient management. The evidence comes from many sources, including prospective randomized trials and prospective cohort studies with rigorous outcomes assessment. Prospective multicenter, randomized studies may provide a sense of generalization of results to the community at large but lack specificity for individual patients. Alternatively, individual operator results are highly specific in determining efficacy of carotid stenting. Arguments against restricting the performance of carotid stenting to the setting of a clinical trial center on the issues of individual operator expertise and the narrow eligibility criteria used in randomized trials. Even if widespread application of carotid stenting were to await the completion of prospective randomized trials, "level 1 scientific evidence" would be available for only a small subset of patients with carotid stenoses. The hypocrisy of vascular surgeons who advocate the restriction of carotid stenting lies first in the decades of carotid endarterectomy (CEA) procedures before availability of "level 1 evidence" of its benefit, and second and more importantly, the widespread application of CEA to large subsets of patients (eg, elderly and females) never satisfactorily studied in prospective randomized trials.
An argument is often forwarded that allowing patients and physicians to choose a preferred therapy unduly impedes recruitment into ongoing randomized trials. Examination of the contemporary development of cardiovascular and cerebrovascular therapies does not support such arguments. The NIH-sponsored Coronary Artery Surgery Study (CASS),1 Bypass versus Angioplasty Revascularization Investigation (BARI),2 North American Symptomatic Carotid Endarterectomy Trial (NASCET),3 and Asymptomatic Carotid Atherosclerosis Study (ACAS)4 were all completed in a clinical environment in which these medical, interventional, and surgical therapies were freely and widely practiced in the community. It might reasonably be argued that widespread utilization and expertise in coronary bypass surgery, coronary angioplasty, and CEA enabled the success of these trials. The same is true for carotid stenting.
Carotid stenting has now been in use for almost a decade. Immediate outcomes in terms of periprocedural neurological events have improved markedly as expertise in the community has grown and embolic protection technology has become available. Restricted application of the therapy is currently more a function of FDA and HCFA intervention than the absence of sound clinical results. Questions have been raised about the influence of surgical societies on these agencies and political and financial motivation to restrict a technique, regardless of its merit, that might decrease the role of carotid endarterectomy.
Operator expertise is pivotal in determining the success of carotid stenting. Unlike the usual pharmacological intervention, efficacy of stenting mostly depends on its application to the patient. This has 2 important implications. The first is that proceeding with a clinical trial without establishing operator expertise would be similar to starting a drug trial without any idea of the formulation, potency, or dose of the agent to be tested. It follows that before proceeding with expensive and time-consuming randomized trials, we must allow operators to develop expertise. Technical expertise can to some extent be taught, but ultimately it only comes with experience in performing a larger number of cases. On average, NASCET and ACAS surgeons had many years of experience and had performed hundreds of cases before CEA was compared with medical therapy in a randomized trial. In the Carotid Revascularization Endarterectomy versus Stenting (CREST) trial,5 stent operators are being rigorously credentialed before they can proceed in the randomized trial. Progress is being impeded precisely because most of the operators have very limited experience and cannot gain experience with the technique given FDA, HCFA, and local medical and political restrictions.
The second important point concerning operator expertise is that in the case of carotid stenting, it is easy to measure. Objective performance criteria can be defined and preprocedural and postprocedural neurological examination can precisely document adverse events. Given that late events have been rare,6 vigorous procedural outcomes assessment (periprocedural stroke and death) can provide an accurate measure of efficacy and basis for local decision-making. Vascular surgeons must of course be held to the same standards. In symptomatic patients, a 
5% 30-day complication rate is acceptable. For asymptomatic patients meeting ACAS criteria (eg, <80 years of age), a 3% 30-day complication rate is acceptable.
Can these outcomes be achieved by individual experienced operators and groups? The current evidence strongly suggests it can be achieved and documented. Current acceptable results need to be examined in the context of routine use of embolic protection devices. Theron at al7 first reported low complication rates with embolic protection. Henry et al8 confirmed this work with a now commercially available distal balloon occlusion, embolic protection system. In a consecutive series of 150 patients, they observed 1.3% nondisabling strokes and 1.6% disabling strokes (including 1 fatality) at 30 days. Parodi et al,9 in 46 consecutive procedures—23 with a variety of embolic protection devices—showed a 9.5% complication rate in the unprotected cohort and 0% in the protected patients. Reimers et al10 reported 84 consecutive patients using 3 embolic protection systems with 1.2% nondisabling and 0% disabling strokes at 30 days. Al-Mubarak et al11 reported a multicenter, consecutive 162-patient experience with a single embolic filter with 1.5% nondisabling and 0% disabling stroke at 30 days. Numerous reports confirm that competent and experienced operators can perform carotid stenting with very low complication rates.12–15 In our own experience with 5 different embolic protection systems, 370 cases have been completed (all with neurological audit) with a 2% nondisabling stroke risk and 0.3% disabling stroke risk.16
In addition, late outcome data are now available. Angiographic restenosis rates, need for repeat intervention, and ipsilateral stroke rates have been extremely low. Freedom from ipsilateral stroke or neurological death after 30 days was 99% at 3 years in 1 large study. Only 3% of patients required any additional intervention on the stented vessel.6 In the prospective, randomized, multicenter Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS), 3-year clinical outcomes were identical for angioplasty/stenting and CEA.17
Undoubtedly, from a patient’s perspective, carotid stenting has some distinct advantages. There is no operative incision on the neck; no general anesthesia, operative risk, or risk of cranial nerve damage; and potential for a day case procedure.18 These undeniable advantages of stenting over CEA are additional reasons that carotid stenting should not be limited to clinical trials. Carotid stenting should be restricted to operators who submit their outcomes to independent peer review and demonstrate efficacious results.
Clinical trials must be undertaken to rigorously validate the methods used in carotid stenting. Comparison to CEA is only 1 issue. More important studies are needed to compare different methods of embolic protection, other adjunctive devices, and pharmacological agents that may further enhance patient care. However, the practice of carotid stenting should not be restricted to randomized trials! In the final analysis, is the lack of prospective randomized trials the real issue? Or is this simply a "smoke screen" conveniently used by the surgical community to hide the "wagons they have circled around" their coveted CEA procedure?
Footnotes
The opinions expressed in this editorial are not necessarily those of the editors or of the American Stroke Association.
The author wishes to acknowledge that he was an active participant in the prospective randomized PTCA versus CABG (BARI) Trial and is co-principal investigator (Intervention) in the Carotid Revascularization Endarterectomy versus Stenting (CREST) Study.
References
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2. Comparison of coronary bypass surgery with angioplasty in patients with multivessel disease: the Bypass Angioplasty Revascularization Investigation (BARI) Investigators. N Engl J Med. 1996; 335: 217–225.
3. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis: North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med. 1991; 325: 445–453.[Abstract]
4. Endarterectomy for asymptomatic carotid artery stenosis: Executive Committee for the Asymptomatic Carotid Atherosclerosis Study. JAMA. 1995; 273: 1421–1428.
5. Hobson RW2nd, Brott T, Ferguson R, Roubin G, Moore W, Kuntz R, Howard G, Ferguson J. CREST: carotid revascularization endarterectomy versus stent trial. Cardiovasc Surg. 1997; 5: 457–458.[CrossRef][Medline] [Order article via Infotrieve]
6. Roubin GS, New G, Iyer SS, Vitek JJ, Al-Mubarak N, Liu MW, Yadav J, Gomez C, Kuntz RE. Immediate and late clinical outcomes of carotid artery stenting in patients with symptomatic and asymptomatic carotid artery stenosis: a 5-year prospective analysis. Circulation. 2001; 103: 532–537.
7. Theron JG, Payelle GG, Coskun O, Huet HF, Guimaraens L. Carotid artery stenosis: treatment with protected balloon angioplasty and stent placement. Radiology. 1996; 201: 627–636.
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9. Parodi JC, La Mura R, Ferreira LM, et al. Initial evaluation of carotid angioplasty and stenting with three different cerebral protection devices. J Vasc Surg. 2000; 32: 1127–1136.[CrossRef][Medline] [Order article via Infotrieve]
10. Reimers B, Corvaja N, Moshiri S, et al. Cerebral protection with filter devices during carotid artery stenting. Circulation. 2001; 104: 12–15.
11. Al-Mubarak N, Colombo A, Gaines PA, et al. Multicenter evaluation of carotid artery stenting with a filter protection system. J Am Coll Cardiol. 2002; 39: 841–846.
12. Jaeger H, Mathias K, Drescher R, et al. Clinical results of cerebral protection with a filter device during stent implantation of the carotid artery. Cardiovasc Intervent Radiol. 2001; 24: 249–256.[CrossRef][Medline] [Order article via Infotrieve]
13. Tubler T, Schluter M, Dirsch O, et al. Balloon-protected carotid artery stenting: relationship of periprocedural neurological complications with the size of particulate debris. Circulation. 2001; 104: 2791–2796.
14. Guimaraens L, Sola MT, Matali A, et al. Carotid angioplasty with cerebral protection and stenting: report of 164 patients (194 carotid percutaneous transluminal angioplasties). Cerebrovasc Dis. 2002; 13: 114–119.[CrossRef][Medline] [Order article via Infotrieve]
15. Angelini A, Reimers B, Della Barbera M, et al. Cerebral protection during carotid artery stenting: collection and histopathologic analysis of embolized debris. Stroke. 2002; 33: 456–461.
16. Iyer SS, Roubin GS, Vitek JJ, et al. Carotid artery stenting with neuroprotection. Circulation. 2002; 39: 30A.Abstract.
17. 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] [Order article via Infotrieve]
18. Al-Mubarak N, Roubin GS, Vitek JJ, New G, Iyer SS. Procedural safety and short-term outcome of ambulatory carotid stenting. Stroke. 2001; 32: 2305–2309.
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