Metabolic Syndrome: Risk for CAD
Abstract & Commentary
By Jonathan Abrams, MD Professor of Medicine, Division of Cardiology, University of New Mexico, Albuquerque Dr. Abrams serves on the speaker's bureau for Merck, Pfizer, and Parke-Davis.
Source: Butler J, et al. Relationship of the metabolic syndrome to quantity of coronary atherosclerotic plaque. Am J Cardiol. 2008;101:1127-1130.
Metabolic syndrome (ms) is an accepted risk factor for adverse coronary events as well as mortality. It has been associated with accelerated coronary atherosclerosis, which is typically subclinical. This study uses 64-slice multidector computed tomography (MDCT), a non-invasive technology that provides visualization of the coronary arteries and can detect both calcified and non-calcified coronary plaque. The data presented here is a secondary analysis of the Rule out MI by Computed Tomography Angiography trial (ROMICTA) assessing Emergency Room visits for chest pain in subjects without definitive evidence for acute MI. The cohort initially consisted of 103 patients, which, for technical reasons, became a final group of 77 patients, 45% of whom had metabolic syndrome. Common clinical problems included hypertension, hyperlipidemia, increased abdominal/waist ratio, and increased BMI. Contrast-enhanced MDCT was performed. The original axial source images were utilized, with thin-slice maximal projections. The coronary circulation was assessed for calcified and non-calcified plaque. Patient characteristics indicated that MS patients were likely to be male, smokers, with a history of hypertension, hyperlipidemia, or CAD.
Results: Patients with MS were more likely to have coronary plaque and a greater degree of plaque distribution then non-MS subjects, with a similar distribution for calcified and non calcified plaque. MS was independently associated with both present and extensive plaque. After adjustment for the Framingham risk score, MS was significantly and independently associated with the presence and extent of plaque, if present, OR 8.4, P = 0.008 after adjustment for all typical risk factors. Butler and colleagues conclude that MS was significantly associated with coronary atherosclerosis for both the presence and extent of calcified and non-calcified plaque. These findings were "independent of the presence of individual risk factors and of the Framingham risk." Also, MS was associated with a higher probability of CAD, and with more extensive disease when adjusted for multiple risk factors. Butler et al noted that MS is associated with insulin resistance and dyslipidemia, promoting a proinflammatory state, including increased lipoprotein oxidation, smooth muscle proliferation, and activation of platelets, as well as prothrombotic pathways. "In summary, all the aspects of atherosclerosis development and progression, and its culmination into adverse clinical events, were observed. Thus, at least part of the risk of MS is directly attributable to advanced atherosclerosis. They state that scoring of the presence and extent of coronary disease may improve therapeutic decision making. They suggest a "targeted approach to high risk patients."
Commentary
The study is small, and the results relatively non specific without coronary angiography. Nonetheless, the fact that metabolic syndrome, when adjusted for multiple risk factors, is a risk for advanced coronary disease, is supported by this data. Patients with non-calcified plaque and calcified plaque were more likely to have MS, and the numbers of plaques were significantly higher in those with MS. Adjustment for Framingham risk factors and the extent of overall plaques also confirmed this relationship. These data appear to contribute to our understanding of coronary risk. Future studies will "lay the foundation... to determine whether such information may improve risk stratification." It should be emphasized that this study may not be as relevant to a population of MS subjects without acute chest pain, as ER subjects may have a higher risk of atherosclerosis.
Metabolic syndrome (ms) is an accepted risk factor for adverse coronary events as well as mortality. It has been associated with accelerated coronary atherosclerosis, which is typically subclinical.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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