I appreciate the interest from Drs Pelz, Bussiere, and Lownie in Ont­ario (“Re: CAS” BCMJ 2009;51[7]:284) to the original article (“Carotid artery stenting by a cardiovascular services department in Canada” BCMJ 2009;51[1]:14-19). 

With every new or competing medical technology there are usually a lot of debates, and carotid artery stenting (CAS) indeed represents one of the most vigorously discussed topics that I have seen in the past 10 years. 

True, although the SAPPHIRE trial has shown the superiority of CAS as compared with carotid endarterectomy (CEA) among symptomatic or asymptomatic high surgical risk patients,[1] we are still waiting for the results of the clinical trials, such as CREST,[2] to provide us information about how they compare with each other among average surgical-risk patients. 

While few people ever challenge the wisdom of treating asymptomatic carotid disease with CEA for primary stroke prevention, albeit its invasiveness and marginal benefit as quoted by Pelz and colleagues, I am a bit perplexed why we shouldn’t choose CAS in our centre for the same group of patients if we could show that CAS could be done safely with <1% periprocedural risk of stroke, <1% for MI, and 0% mortality in our series, which probably is far better than the results of any trials or registries ever published in the CEA literature. 

Similarly, in the past, few people ever challenged the surgeons to do combined cardiac surgery and carotid surgery in the same setting until recently, when several studies have reported the superiority of CAS followed by cardiac surgery as compared with combined carotid and cardiac surgeries.

Pelz and colleagues also asked who would manage periprocedural complication during CAS. Again, this is the same type of question that one could ask in post-CEA complication management. At the Royal Columbian Hospital, complications after CAS are fortunately infrequent. 

Nevertheless, the interventionalist would be responsible for taking care of any hemodynamic challenge, hyperperfusion syndrome, and any stroke event related to the procedure.

While in the original article I mentioned that “dilation of a stent… is crucial for reducing restenosis risk,” it by no means implies dilating “carotid arteries to maximum diameter,” as mis­interpreted by Pelz and colleagues. On the contrary, in the original article I warned about aggressive dilation of a stent in causing slow flow, especially among symptomatic lesions or in elderly patients.

Within the next few years, several more comparative trials about CAS vs CEA will be completed and they will provide more insight about patient selection for each treatment modality. CAS, CEA, and medical therapy will continue to be complementary treatments. 

On the other hand, I would emphasize that the outcomes of a clinical trial do not imply reproducibility in a local institution, and vice versa, since the outcomes depend largely on the local expertise. In other words, whether a procedure should be done or not by a certain operator or at a certain institution largely depends on whether the local operator can meet the benchmark established by the current guidelines, and these would be <6% perioperative risk (stroke/death) for symptomatic patients, and <3% risk for asymptomatic patients, in carotid revascularization.[3]

—Albert W. Chan, MD
New Westminster


1. 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.
2. Hobson RW, 2nd, Brott T, Ferguson R, et al. CREST: Carotid revascularization endarterectomy versus stent trial. Cardiovasc Surg 1997;5:457-458.
3. Biller J, Feinberg WM, Castaldo JE, et al. 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. 

Albert W. Chan, MD, FRCPC,. Re: CAS. BCMJ, Vol. 51, No. 9, November, 2009, Page(s) 383 - Letters.

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