Does metabolic syndrome predict silent carotid stenosis in coronary patients?

Abstract

The metabolic syndrome (MS) is a clustering of risk factors whose association with cardiovascular diseases and type 2 diabetes has been well documented [1]. Nevertheless, the clinical value of diagnosing MS remains controversial, as there is no accordance between different series in the predictive value for adverse cardiovascular outcomes [2], and the ability of MS to improve risk prediction beyond that achieved by conventional cardiovascular risk factors has not been clearly shown. The need for studies targeted on selected patient subgroups has been recently highlighted; in this perspective, a valuable approach may emerge from considering MS as a possible indicator of multi-site advanced atherosclerosis among patients at high cardiovascular risk. In this observational, case–control study we restricted our analysis to the subgroup of patients with a recent first clinical manifestation of coronary artery disease (CAD) and without a previous cerebrovascular event or documentation of carotid examination. The aim of our study was to evaluate the association between MS and the presence of silent carotid stenosis[50% obtained by means of ultrasonographic screening. A sample of 168 consecutive referred patients with coronary angiography after a first manifestation of CAD (acute coronary syndrome in 52%, stable angina in 34% and silent myocardial ischemia in 14% of cases, respectively) was considered. The patients had a mean age of 65 ± 8 years, in 31% of cases were active smokers, and in 26% of cases presented a depressed left ventricular dysfunction. The prevalence of conventional cardiovascular risk factors was as follows: hypercholesterolemia 60%, hypertension 63%, diabetes 30% and family history of vascular events 53%. The patients were studied while in hospital by color Doppler ultrasonographic examinations of both carotid arteries; an intima-media thickness (IMT)\1.00 mm identified absence of lesions, while an increased IMT identified carotid atherosclerosis. The severity of carotid atherosclerosis was evaluated by using both the percentage diameter stenosis and parameters of the flow velocity pattern. The greatest stenosis observed on the right or left side identified patients with at least moderate ([50% diameter stenosis) carotid stenosis. A morphologic evaluation of carotid plaques to differentiate stable from unstable lesions was not performed. The MS was diagnosed according to the 2001 NCEP guidelines [3] when three or more of the following factors were present: waist circumference[102 and 88 cm in men and women, respectively, triglycerides C150 mg/dL, highdensity lipoprotein cholesterol (HDL-C)\40 and 50 mg/dL in men and women, respectively; blood pressure C130/ C85 mmHg, and fasting glucose C110 mg/dL. The odds ratio (OR) with confidence interval (CI) 95% for the presence of[50% carotid stenosis in patients with MS and other cardiovascular risk factors was calculated. Globally, 149 patients out of 168 (89%) had carotid atherosclerosis, with [50 and [70% carotid stenosis in 38 (23%) and 11 (7%) cases, respectively. No carotid occlusion was documented. The MS (Fig. 1) was detected in 26.3% of patients with[50% carotid stenosis and 26.9% of controls (OR 0.97; 95% CI 0.43, 2.20). Among other cardiovascular risk factors, only hypertension (OR 2.15; 95% CI 0.94, 4.91) and an age over 65 years (OR 2.96; 95% CI 1.37, 6.36) increased the odds of having a [50% carotid stenosis. M. Ambrosetti (&) R. F. E. Pedretti Division of Cardiology, IRCCS Fondazione Salvatore Maugeri, Institute of Tradate (VA), Via Roncaccio, 16, 21049 Tradate, Italy e-mail: m.ambrosetti@clinicaleterrazze.com