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Long-term Outcomes of Carotid Endarterectomy Versus Stenting in a Multicenter Population-based Canadian Study

Hussain, Mohamad A., MD*,¶; Mamdani, Muhammad, PharmD, MPH§,**,††,‡‡,§§; Tu, Jack V., MD, PhD||,**,‡‡,||||; Saposnik, Gustavo, MD, MSc†,§,||,**,‡‡; Aljabri, Badr, MD*,§§,¶¶; Bhatt, Deepak L., MD, MPH***; Verma, Subodh, MD, PhD‡,§,¶,§§; Al-Omran, Mohammed, MD, MSc*,§,¶,§§,¶¶

doi: 10.1097/SLA.0000000000002301

Objective: To compare the long-term outcomes of patients treated with carotid endarterectomy and carotid-artery stenting.

Background: Evidence for the long-term safety and efficacy of carotid-artery stenting compared with endarterectomy is accumulating from randomized trials. However, comparative data on the long-term outcomes of carotid revascularization strategies in real world practice are lacking.

Methods: We conducted a population-based, multicenter, observational cohort study using validated linked databases from Ontario, Canada. We identified all individuals treated with carotid endarterectomy and stenting (2002–2014), and followed them up to 2015. We compared long-term (up to 13 years) and 30-day outcomes of each strategy using multilevel multivariable Cox proportional-hazards models, and conducted confirmatory analyses using propensity-score matching methods.

Results: In all, 15,525 patients received carotid-artery revascularization. Rate of the primary composite outcome of 30-day death, stroke, or myocardial infarction plus any stroke during 13-year follow-up was higher with stenting (16.3%) compared with endarterectomy (9.7%) [adjusted hazard ratio (HR) 1.57, 95% confidence interval (CI) 1.43–1.73, P < 0.001). The increased risk with stenting was observed regardless of age, sex, intervention year, carotid-artery symptoms, or diabetes. The primary outcome was driven by higher rates of 30-day stroke (adjusted HR 1.59, 95% CI 1.29–1.95), 30-day death (adjusted HR 2.62, 95% CI 2.20–3.13), and long-term stroke >30 days after the procedure (adjusted HR 1.47, 95% CI 1.36–1.59) with stenting; 30-day myocardial infarction was lower with stenting (adjusted HR 0.70, 95% CI 0.57–0.86). These results were confirmed with 1:2 propensity-score matching (HR for primary composite outcome with stenting 1.55, 95% CI 1.31–1.83, P < 0.001).

Conclusions: Compared with carotid endarterectomy, stenting was associated with an early and sustained approximately 55% increased hazard for major adverse events over long-term follow-up. Although nonrandomized, these results raise potential concerns about the interchangeability of carotid endarterectomy and stenting in the context of actual clinical practice.

*Division of Vascular Surgery, St. Michael's Hospital, Toronto, Ontario, Canada

Division of Neurology, St. Michael's Hospital, Toronto, Ontario, Canada

Division of Cardiac Surgery, St. Michael's Hospital, Toronto, Ontario, Canada

§Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada

Department of Surgery, University of Toronto, Toronto, Ontario, Canada

||Department of Medicine, University of Toronto, Toronto, Ontario, Canada

**Institute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, Ontario, Canada

††Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada

‡‡Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada

§§King Saud University-Li Ka Shing Collaborative Research Program, King Saud University, Riyadh, Kingdom of Saudi Arabia

¶¶Department of Surgery, King Saud University, Riyadh, Kingdom of Saudi Arabia

||||Division of Cardiology, Schulich Heart Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

***Brigham and Women's Hospital Heart & Vascular Center, Harvard Medical School, Boston, MA.

Reprints: Mohammed Al-Omran, MD, MSc, FRCSC, Professor and Head, Division of Vascular Surgery, St. Michael's Hospital, 30 Bond Street, Suite 7-074, Bond Wing, Toronto, Ontario M5B1W8, Canada. E-mail:

Funding: The Physicians’ Services Inc. Foundation and the King Saud University-Li Ka Shing Collaborative Research Program funded this study. This study was also supported by the Institute for Clinical Evaluative Sciences (ICES), which is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care (MOHLTC). The opinions, results, and conclusions reported in this paper are those of the authors and are independent from the funding sources. No endorsement by ICES or the Ontario MOHLTC is intended or should be inferred.

Financial disclosures: M.A.H. is supported by Ontario Ministry of Health-Clinical Investigator Program funding, and by a University of Toronto Postgraduate Research Award (Joseph M. West Family Memorial Fund) for this study. M.A.H. also won a Young Investigator Award—Stroke at the European Society of Cardiology Congress on August 28, 2016 in Rome, Italy for this study. All datasets used in this study were linked using unique encoded identifiers and analyzed at ICES. Parts of this material are based on data and information compiled and provided by the Canadian Institute for Health Information (CIHI). However, the analyses, conclusions, opinions and statements expressed herein are those of the author, and not necessarily those of CIHI. D.L.B. reports grants from Amarin, grants from AstraZeneca, grants from Bristol-Myers Squibb, grants from Eisai, grants from Ethicon, grants from Medtronic, grants from Sanofi Aventis, grants from The Medicines Company, other from FlowCo, other from PLx Pharma, other from Takeda, personal fees from Duke Clinical Research Institute, personal fees from Mayo Clinic, personal fees from Population Health Research Institute, personal fees and nonfinancial support from American College of Cardiology, personal fees from Belvoir Publications, personal fees from Slack Publications, personal fees from WebMD, personal fees from Elsevier, other from Medscape Cardiology, other from Regado Biosciences, other from Boston VA Research Institute, personal fees and non-financial support from Society of Cardiovascular Patient Care, non-financial support from American Heart Association, personal fees from HMP Communications, grants from Roche, personal fees from Harvard Clinical Research Institute, other from Clinical Cardiology, personal fees from Journal of the American College of Cardiology, other from VA, grants from Pfizer, grants from Forest Laboratories, grants from Ischemix, other from St. Jude Medical, other from Biotronik, other from Cardax, other from American College of Cardiology, other from Boston Scientific, grants from Amgen, outside the submitted work. None of the other authors report conflicts.

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