Background and Objectives:Increased carotid intima-media thickness (IMT) is known to be associated withadverse cardiovascular events in the patients with risk factors or established atherosclerosis. However, the prognosticimportance of carotid IMT is uncertain in the patients who underwent percutaneous coronary intervention (PCI).We sought to evaluate the association of carotid IMT with major adverse cardiovascular events (MACE) andrestenosis in the patients who underwent PCI. Subjects and Methods:The study population consisted of 308consecutive patients who underwent PCI, and they were followed up for mean of 30.6±13.3 months. Base onthe median values of carotid IMT, which was measured in the right common carotid artery at the time of PCIwith using high-resolution ultrasound and a semiautomatic method, the subjects were divided into the thick(n=156, 1.003±0.14 mm) and thin IMT (n=152, 0.748±0.07 mm) groups, and they were followed up for atleast 1 year. Results:Patients with thick carotid IMT were older (61±9 years vs. 57±10 years, respectively, p=0.001),had a higher body mass index (25.0±3.0 vs. 23.9±4.0, respectively, p=0.017), a history of previous myocardialinfarction (20% vs. 9%, respectively, p=0.008), more multivessel disease and more restenosis (34.6% vs. 23.0%,respectively, p=0.025) than those patients with a thin carotid IMT. However other MACEs such as death,myocardial infarction, stroke, heart failure and target lesion revascularization did not show any significant differencesbetween the two groups. Multivariate Cox regression analysis showed that carotid IMT was an independent predictorof restenosis (odds ratio: 1.754, 95% confidence interval: 1.1296 to 2.726, p=0.012). Conclusion:An increasedcarotid IMT is associated with restenosis, but it does not have clinical prognostic importance for the patientswho underwent PCI during a mean follow up period of 31 months. (Korean Circulation J 2007;37:103-107)