Metabolic syndrome predicts increased coronary artery disease burden
MedWire News: The presence of abnormal glucose handling or the metabolic syndrome in patients with an abnormal stress echocardiogram predicts an increased risk for obstructive coronary artery disease (CAD), US researchers believe.
They say that their study supports the use of stress echo testing to detect CAD in patients irrespective of the presence of the metabolic syndrome.
Francisco Lopez-Jiminez (Mayo Clinic, Rochester, Minnesota) and team investigated reports that the presence of glucose handling abnormalities is associated with an elevated rate of false-positive results on stress testing.
In a retrospective study, they identified 583 consecutively recruited patients without known CAD who had an abnormal stress echocardiogram and subsequently underwent coronary angiography.
In all, 158 (36%) participants met the National Cholesterol Education Panel criteria for the metabolic syndrome. Angiography confirmed the presence of CAD in 84.2% of these individuals and in 80.7% of those without the syndrome, a non-significant difference.
After adjusting for pre-test probability of CAD, smoking history, and lipid levels, the metabolic syndrome predicted the presence of obstructive CAD with an odds ratio (OR) of 1.46. This value was only of borderline statistical significance.
However, the metabolic syndrome in conjunction with impaired fasting glucose (IFG) was strongly predictive of CAD, with an OR of 2.06. Diabetes also significantly predicted CAD, with an OR of 2.28.
The researchers say that symptomatic patients with the metabolic syndrome tend to have a higher likelihood of obstructive CAD when referred to coronary angiography after an abnormal stress echocardiogram.
"Our results concur with prior studies which reported a higher burden of disease in patients with metabolic syndrome and even more advanced disease in patients with 'more severe' metabolic syndrome status," Lopez-Jiminez et al report.
They propose two hypotheses to explain their observations. First, patients with IFG tend to have higher circulating insulin levels, which have in turn been linked with endothelial dysfunction and atherosclerosis.
Second, patients with the metabolic syndrome and IFG have lower adiponectin levels, a molecule with known anti-atherogenic effects.
"Future studies with measurement of these biomarkers are warranted," the team concludes.
"Our study supports the diagnostic utility of stress echocardiography in symptomatic patients with the metabolic syndrome."
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By Joanna Lyford