Correspondence
Carotid Stenting versus Endarterectomy
N Engl J Med 2008; 359:311-313July 17, 2008
- Article
To the Editor:
Gurm and colleagues (April 10 issue)1 conclude that carotid stenting is not inferior to carotid endarterectomy in high-risk patients. This conclusion may be misleading. First, patients were at high risk not for stroke but for surgery. Second, in the absence of controls, the best strategy could have been medical therapy alone. A pooled analysis of the Asymptomatic Carotid Atherosclerosis Study2 and the Asymptomatic Carotid Surgery Trial3 shows that in patients with asymptomatic carotid artery stenosis (71% of patients randomly assigned to a study group in the Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy [SAPPHIRE] study) who did not undergo immediate surgery, the risks after a mean follow-up of 3.16 years were 8.6% for any stroke and 14.3% for any cause of death, which are similar to the risks observed in the stenting group of the SAPPHIRE trial after 3 years of follow-up (9.0% and 18.6%, respectively). Finally, if the subjects were at high risk for surgery, which was therefore not an appropriate option for most patients, a noninferior technique cannot be recommended either.
3 ReferencesClotilde Balucani, M.D.
Charlotte Cordonnier, M.D., Ph.D.
Lille University Hospital, 59037 Lille, France
clotilde_balucani@hotmail.com 1
Gurm HS ,Yadav JS ,Fayad P , et al. Long-term results of carotid stenting versus endarterectomy in high-risk patients. N Engl J Med 2008;358:1572-1579
Full Text | Web of Science | Medline2
Executive Committee for the Asymptomatic Carotid Atherosclerosis Study
CrossRef | Web of Science3
Halliday A ,Mansfield A ,Marro J , et al. Prevention of disabling and fatal strokes by successful carotid endarterectomy in patients without recent neurological symptoms: randomised controlled trial. Lancet 2004;363:1491-1502[Erratum, Lancet 2004;364:416.]
CrossRef | Web of Science | Medline
To the Editor:
How many patients had atrial fibrillation in the SAPPHIRE study, which compared carotid artery stenting with endarterectomy? We would expect a high prevalence of atrial fibrillation because of relevant risk factors in the study population, including older age, hypertension, coronary heart disease, heart failure, and smoking.1 Differences in the prevalence of atrial fibrillation might have contributed to differences in the incidence of stroke. Were the use of antiplatelet agents, the intensity of medical therapy, and bleeding complications registered? How would the authors explain the rates of stroke that were higher among asymptomatic patients (10.3% in the stenting group and 9.2% in the endarterectomy group) than among symptomatic patients (6.0% in the stenting group and 8.7% in the endarterectomy group)? How would they explain the decreasing divergence of the survival curves at the 3-year follow-up?
1 ReferencesClaudia Stöllberger, M.D.
Josef Finsterer, M.D., Ph.D.
Krankenanstalt Rudolfstiftung, 1030 Vienna, Austria
claudia.stoellberger@chello. at 1
Stewart S ,Hart CL ,Hole DJ ,McMurray JJ . Population prevalence, incidence, and predictors of atrial fibrillation in the Renfrew/Paisley study. Heart 2001;86:516-521
CrossRef | Web of Science | Medline
To the Editor:
Gurm et al. report long-term follow-up data from the SAPPHIRE trial, which showed no significant difference between carotid artery stenting and endarterectomy in outcomes at 3 years. In their study, 14.4% of the patients in the stenting group and 29.9% of the patients in the endarterectomy group were lost to follow-up. It has been suggested that a rate of loss that is less than 5% probably leads to little bias, whereas a rate of loss that is greater than 20% potentially poses serious threats to validity.1 Therefore, the influence of loss bias on the interpretation of these results is substantial and should be considered. Moreover, a previous report2 indicated that 310 patients received the assigned treatment. When they compared carotid artery stenting with endarterectomy at 3 years, the authors calculated all the percentages on the basis of the 334 patients who were randomly assigned to a study group originally. We would like to know why the authors did not include an analysis based on patients receiving the assigned treatment.
2 ReferencesJin-Tai Yu, M.D.
Lan Tan, M.D.
Qingdao Municipal Hospital, Qingdao 266071, China
dr.tanlan@163. com 1
Sackett DL, Richardson WS, Rosenberg W, Haynes RB. Evidence-based medicine: how to practice and teach EBM. New York: Churchill Livingstone, 1997.
2
Yadav JS ,Wholey MH ,Kuntz RE , et al. Protected carotid-artery stenting versus endarterectomy in high-risk patients. N Engl J Med 2004;351:1493-1501
Full Text | Web of Science | Medline
Author/Editor Response
We agree with Balucani and Cordonnier that there are no data from randomized trials to support or refute the need for revascularization in addition to best medical therapy in patients with severe carotid stenosis who are at high surgical risk. As we noted in our article, the SAPPHIRE trial randomly assigned only patients who were referred by their physicians for carotid revascularization to undergo either surgery or protected stenting if a surgeon and an interventionalist thought that both procedures could be performed with an acceptable risk of procedural complications. These data cannot be extrapolated to all patients with carotid stenosis, and the need for treatment in each patient must be individualized on the basis of a careful assessment of the patient's risk of stroke with medical therapy or revascularization as well as his or her expected long-term survival.
With regard to the comments of Stöllberger and Finsterer, 29 patients in the endarterectomy group (17%) and 14 in the stenting group (8%) had a history of atrial fibrillation. In this group, two patients who underwent endarterectomy had ipsilateral strokes (on day 2 and day 87), as did two in the stenting group (on day 0 and day 182). Among patients with no history of atrial fibrillation, there was no significant difference at 3 years between stenting and surgery with regard to the cumulative incidence of death (18% and 20%, respectively), stroke (8% and 9%, respectively), or the prespecified major secondary end point (23% and 26%, respectively). The details of antithrombotic therapy during long-term follow-up were not recorded, but there were no reported major bleeding events after 30 days. We believe that the small numbers of patients and events in the subgroups of patients with asymptomatic and symptomatic disease preclude any meaningful conclusions, although we agree with the concern about possibly high rates of events among asymptomatic patients who received either treatment. We believe that the survival curves should be interpreted as being not significantly different, with the changes after 1 year indicating only three more ipsilateral strokes and one less death from a neurologic cause in the stenting group.
Yu and Tan are concerned about data being presented on an intention-to-treat basis rather than on an as-treated basis. We believe that the important safety issues in this study require an intention-to-treat analysis.1 We also included the estimates of events using survival methods to partially correct for incomplete follow-up. The results at 3 years, however, were similar when the population was analyzed on an as-treated basis for the cumulative incidence of the major secondary end point (25% in the stenting group vs. 28% in the endarterectomy group) and ipsilateral stroke (6% in the stenting group vs. 5% in the endarterectomy group).
1 ReferencesHitinder Gurm, M.D.
University of Michigan School of Medicine, Ann Arbor, MI 48109-5853Donald E. Cutlip, M.D.
Harvard Clinical Research Institute, Boston, MA 02215
don.cutlip@hcri. harvard. edu
