Angioplasty and stenting should be performed only in the setting of a clinical trial.

Abstract

Dr Roubin cites exciting observational data supporting carotid artery stenting as treatment for focal carotid artery disease. Unfortunately, observational studies cannot substitute for randomized trials.1 The design is not experimental. The treatment for each patient is chosen by the interventionalist, and so selection bias cannot be avoided. Assessment of outcomes is vulnerable to investigator ascertainment bias and in some cases conflict of interest. Full reporting cannot be ensured, nor can publication bias be avoided. Comparison to historical controls is not valid because the competing medical and surgical treatments have advanced. For surgical therapy, randomized trials have shown that absolute risk reduction may be high as 5% per year for symptomatic patients with stenosis ≥70%,2,3⇓ approximately 1% per year for symptomatic patients with stenosis ≥50% to 69%,3 and up to 1% per year in asymptomatic patients with stenosis ≥60%, when surgical results are optimal.4 Benefits …