Influence of Abnormal Glucose Metabolism on Coronary Microvascular Function After a Recent Myocardial Infarction

Objectives: This study sought to assess the association between abnormal glucose metabolism and abnormal coronary flow reserve (CFR) in patients with a recent acute myocardial infarction (AMI). Background: Mortality and morbidity after AMI is high among patients with abnormal glucose metabolism, which may be related to abnormal microcirculation. Methods: We studied 183 patients with a first AMI. In 161 patients with no history of diabetes mellitus (DM), an oral glucose tolerance test was performed, and patients were categorized according to World Health Organization criteria for whole blood glucose into 3 groups. After coronary angiography and revascularization, a comprehensive transthoracic echocardiogram and noninvasive assessment of CFR was performed in the distal part of left descending artery, as an indicator of microvascular function. Adenosine was administered by intravenous infusion (140 μg/kg/min) to obtain the hyperemic flow profiles. The CFR was defined as the ratio of hyperemic to baseline peak diastolic coronary flow velocities. Results: Median CFR was 1.9 (interquartile range [IQR] 1.4 to 2.4], and 109 (60%) patients had a CFR ≤2. The lowest CFR was seen in patients with a history of DM (1.4 [IQR 1.4 to 1.7], n = 22) and in patients with newly diagnosed DM (1.6 [IQR 1.3 to 2], n = 39), whereas CFR did not differ in patients with abnormal glucose tolerance (2.1 [IQR 1.4 to 2.6], n = 58) and in patients with normal glucose tolerance (2.2 [IQR 1.7 to 2.6], n = 62). In a stepwise logistic regression model adjusting for age, sex, site and size of AMI, heart rate, risk factors of the metabolic syndrome, degree of angiographic evidence of coronary artery disease, and medical therapy, newly diagnosed DM (odds ratio: 3.0) and a history of DM (odds ratio: 9.9) remained significant predictors of CFR <2, whereas impaired glucose tolerance was not. Conclusions: CFR is decreased in patients with known or newly diagnosed DM even after adjustment of possible confounders, whereas CFR in patients with impaired glucose tolerance seems less affected. (Coronary Flow Reserve and Glucometabolic State [CFRGS]; NCT00845468).