The Brighter the Light, the Darker the Shadow

> “However beautiful the strategy, you should always look at the results.” > > Sir Winston Churchill (1874–1965)See related article, p 120.The management of asymptomatic carotid disease remains controversial and associated with extremes of practice. In the United States, >90% of interventions are undertaken in asymptomatic patients,1 compared with 0% in Denmark.2 Notwithstanding debates about whether the randomized trials are too historical to influence practice, or whether there has been a real/sustained reduction in annual stroke rates with modern best medical therapy, one absolute caveat within every practice guideline is that carotid interventions should only be undertaken in centers with an audited 30-day death/stroke rate ≤3%.3During the past 15 years, technological advances and increasing experience have seen carotid artery stenting (CAS) emerge as a credible alternative to carotid endarterectomy (CEA) and the proportion of asymptomatic patients in the United States treated by CAS has increased from 3% in 1998 to 13% in 2008.4 This happened despite the absence of adequately powered randomized trials and was largely the consequence of industry sponsored high risk for surgery registries that ultimately demonstrated procedural risks compatible with the 3% American Heart Association (AHA) threshold.4–6 Not surprisingly, the proportion of asymptomatic patients undergoing CAS will increase after publication of Carotid Revascularization Endarterectomy or Stent Trial (CREST),7 which was singularly influential in the AHA updating its 2011 guidelines to advise that CAS might be an alternative to CEA in highly selected, average-risk asymptomatic patients.8 Although CREST was never powered to determine whether CAS was safer/equivalent to CEA in …