THE ROLE OF CAROTID ARTERIAL INTIMA-MEDIA THICKNESS IN PREDICTING CLINICAL CORONARY EVENTS

Background: Carotid arterial intima-media thickness is used as a nonin vasive surrogate end point to measure progression of atherosclerosis, but its relation to coronary events has not been fully explored. Objec tive: To determine whether carotid arterial intimamedia thickness pred icts coronary events. Design: Long-term follow-up (average, 8.8 years) of a previously assembled cohort of persons who completed the 2-year Cholesterol Lowering Atherosclerosis Study, a randomized arterial imag ing trial designed to study the effects of lipid lowering on progressi on of atherosclerosis. Setting: University-based ultrasonography labor atory. Patients: 146 men 40 to 59 years of age who had previously had coronary artery bypass graft surgery. Measurements: Preintrusive ather osclerosis in the common carotid artery was evaluated every 6 months w ith B-mode ultrasonography, and intrusive atherosclerosis in the coron ary arteries was evaluated at baseline and at 2 years with quantitativ e coronary angiography. After the trial, the incidences of coronary ev ents (nonfatal acute myocardial infarction, coronary death, and corona ry artery revascularization) were documented. Results: For each 0.03-m m increase per year in carotid arterial intima-media thickness, the re lative risk for non-fatal myocardial infarction or coronary death was 2.2 (95 % Cl, 1.4 to 3.6) and the relative risk for any coronary event was 3.1 (Cl, 2.1 to 4.5) (P < 0.001). Absolute intima-media thickness was also related to risk for clinical coronary events (P < 0.02). Abs olute thickness and progression in thickness predicted risk for corona ry events beyond that predicted by coronary arterial measures of ather osclerosis and lipid measurements (P < 0.001). Conclusion: Noninvasive B-mode ultrasonographic measurement of progression of intima-media th ickness in the distal common carotid artery is a useful surrogate end point for clinical coronary events.