• carotid artery stenosis;
  • outcome assessment;
  • prevention;
  • stroke;
  • therapy

Background and purpose:  Data on current cardiovascular event rates in patients with asymptomatic carotid artery stenosis (ACAS) are sparse. We compared the 1-year outcomes of patients with ACAS ≥70% versus patients without ACAS in an international, prospective cohort of outpatients with or at risk of atherothrombosis.

Methods:  The Reduction of Atherothrombosis for Continued Health Registry enrolled patients with either ≥3 atherothrombotic risk factors or established atherothrombotic disease. We investigated the 1-year follow-up data of patients for whom physicians reported presence/absence of ACAS at the time of inclusion.

Results:  Compared with patients without ACAS (= 30 329), patients with ACAS (= 3164) had higher age- and sex-adjusted 1-year rates of transient ischaemic attack (3.51% vs. 1.61%, < 0.0001), non-fatal stroke (2.65% vs. 1.75%, = 0.0009), fatal stroke (0.49% vs. 0.26%, = 0.04), cardiovascular death (2.29% vs. 1.52%, = 0.002), the composite end-point cardiovascular death/myocardial infarction/stroke (6.03% vs. 4.29%, < 0.0001) and bleeding events (1.41% vs. 0.81%, = 0.002). In patients with ACAS, Cox regression analyses identified history of cerebrovascular ischaemic events as most important predictor of future stroke (HR 3.21, 95% CI 1.82–5.65, < 0.0001).

Conclusion:  Asymptomatic carotid artery stenosis was associated with high 1-year rates of cardiovascular and cerebrovascular ischaemic events. Stroke was powerfully predicted by prior cerebrovascular ischaemic events.