Impact of Carotid Atherosclerosis on the Risk of Adverse Cardiac Events in Patients With and Without Coronary Disease

BACKGROUND AND PURPOSE: Carotid atherosclerosis (CA) is reportedly a strong predictor of imminent cardiac events even in the absence of established coronary artery disease (CAD). We examined the differential impact of CA on the risk of major adverse cardiovascular events in patients with and without CAD diagnosed angiographically. METHODS: We conducted a follow-up survey of 1391 patients who underwent clinically driven coronary angiography and a same-day carotid ultrasound and Doppler study. Definitions of CAD, CA, and carotid artery stenosis were in accordance with current practice guidelines. RESULTS: Of 1391 patients, angiographic CAD was present in 1105 (79%) patients. Mean and median follow-up was 1574 and 1702 days, respectively. Rates of the primary composite major adverse cardiovascular event end point were higher among patients with CAD compared with those without CAD (48% versus 20%; P<0.001), whereas the rates of all-cause mortality (10% versus 9%; P=0.81) and stroke (7% versus 5%; P=0.3) did not differ significantly between both groups. Carotid artery stenosis and CA were associated with an increased risk of the composite major adverse cardiovascular event end point among patients without CAD (hazard ratio=3.17 [95% confidence interval, 1.52-6.60]; P<0.01; and hazard ratio=1.69 [0.95-3.01]; P=0.07, respectively) though not in patients with CAD. Carotid artery stenosis was associated with an increased risk of all-cause mortality among patients without CAD (hazard ratio=2.93 [1.09-7.87]; P=0.03]) though not among those with CAD. CONCLUSIONS: CA and carotid artery stenosis are independent predictors of major adverse cardiovascular event in patients undergoing coronary angiography. The prognostic implications of carotid disease are imparted predominantly in patients without pre-existent CAD.