Angiology | 2019
Prediabetes and Atherosclerotic Disease
Abstract
Diabetes mellitus (DM) is characterized by increased cardiovascular morbidity and mortality as a result of advanced atherosclerosis that occurs at an earlier age and affects multiple vessels. Increased cardiovascular risk is present even in the prediabetic state. There is an accumulating evidence showing that nondiabetic levels of glucose metabolism are associated with an elevated risk of cardiovascular events and poor prognosis. A meta-analysis of 18 studies showed a significant increase in risk for the development of cardiovascular disease (20%) in patients with prediabetes compared to those with normoglycemia. In a previous issue of Angiology, Açar et al evaluated the impact of prediabetic status on coronary atherosclerosis burden in patients with first-time acute coronary syndrome (ACS) who underwent urgent coronary angiography. Their findings are impressive, since they found that the coronary atherosclerosis burden is more advanced in patients with prediabetes than in nondiabetes and comparable between patients with prediabetes and diabetes in first presentation ACSpatients. Therefore, it can be concluded that the atherosclerotic burden is present before the clinical manifestation of DM per se. In accordance with the results of the study by Açar et al, another trial using coronary angiography showed that coronary atherosclerosis is present in patients with impaired glucose tolerance leading to the earlier onset of cardiovascular events. Imaging techniques have shown that lipid-rich plaques are present in coronary lesions in the prediabetic status. The pathophysiologic defects underlying prediabetes and cardiovascular disease include insulin resistance, aand b-cell dysfunction, increased lipolysis, inflammation, and suboptimal incretin effect. Furthermore, it is well known that hyperglycemia, free fatty acids, and insulin resistance alter the function and structure of blood vessels. The above, taken together with vasoconstriction and inflammation, promote coronary atherosclerosis in the prediabetic status. Prediabetic patients with ACS have worse in-hospital clinical outcomes compared to patients without DM. In a prospective study of patients without known DM admitted with acute myocardial infarction, there was a graded relation between fasting plasma glucose and 30-day mortality. Additionally, a retrospective analysis of the Global Registry of Acute Coronary Events (GRACE) registry demonstrated an odds ratio for in-hospital mortality of 1.51 in patients admitted with ACS and a fasting plasma glucose level of 5.55 to 6.94 mmol/L (214-268 mg/dL) compared with those admitted with a fasting plasma glucose <5.55 mmol/L (<214 mg/dL). Açar et al emphasize the important role of cardiologists not to miss the opportunity to diagnose prediabetes and DM when patients present with ACS. The European Society of Cardiology and the European Association for the Study of Diabetes already advocated investigating glucose metabolism in patients without known DM but with established cardiovascular disease, by performing an oral glucose tolerance test. In patients with asymptomatic diabetes, screening for coronary artery disease is not recommended by the guidelines but the beneficial effects of early recognition of diabetic and prediabetic status is critical. Both conservative medical therapy and invasive revascularization have been used successfully for the treatment of coronary artery disease in this population. More multicenter studies are needed to access the prognosis of ACS among patients with DM and prediabetic status. In conclusion, early detection of glucometabolic abnormalities at the time of admission for ACS may provide a unique opportunity to identify patients who might benefit from targeted intervention to decrease the risk of progression to DM.