Effect of a significant asymptomatic unilateral carotid artery stenosis on outcomes in patients undergoing coronary artery bypass grafting.

Background: Occurrence of a stroke is a major concern in patients undergoing coronary artery bypass grafting (CABG). It remains uncertain whether significant asymptomatic carotid artery stenosis (CAS) is associated with stroke incidence in such patients. Aim: To investigate the incidence of cerebrovascular events, myocardial infarction (MI), and death in patients with a significant asymptomatic CAS undergoing CABG. Methods: We prospectively evaluated 123 consecutive patients with documented carotid artery duplex Doppler ultrasound examination who underwent isolated CABG. Patients with a significant (>= 60%) asymptomatic unilateral CAS (n = 35) were compared with those without a significant CAS (n = 88) to assess the rates of stroke, MI and mortality after CABG. Results: No significant differences between patients with a significant asymptomatic unilateral CAS and those without a significant CAS in regard to age (p = 0.5955), presence of hypertension (p = 0.2343), diabetes (p = 0.5495), smoking (p = 0.7891), serum creatinine (p = 0.47) and left ventricular systolic function as evaluated by ejection fraction (p = 0.3789). No cerebrovascular events, MI and deaths occurred during the first 30 days postoperatively. At 12 months, no differences were seen between the groups in the incidence of MI (p = 0.1005) and mortality (p = 0.3959). However, a trend towards higher stroke incidence was noted among patients with a significant asymptomatic unilateral CAS (p = 0.0692). The primary combined endpoint (stroke, MI, and mortality) occurred in 40% of patients with a significant asymptomatic unilateral CAS and 17.05% of patients without a significant CAS (p = 0.0097). Linear regression analysis showed an association between significant asymptomatic unilateral CAS and stroke (p = 0.0041), and between significant asymptomatic unilateral CAS and the primary end point (p = 0.0475). Conclusions: The presence of a significant asymptomatic unilateral CAS does not increase the risk of stroke, MI and mortality within 30 days after CABG but is was associated with an increased risk of cardiovascular events during the first 12 months postoperatively.