Persistent abnormal coronary flow reserve in association with abnormal glucose metabolism affects prognosis in acute myocardial infarction

Objectives: To evaluate changes in coronary flow reserve (CFR) over time after acute myocardial infarction (AMI) in relation to left ventricular (LV) function and glucometabolic state and prognostic implication of abnormal CFR. Methods: 154 patients with first time AMI had a comprehensive assessment of the LV function and CFR at baseline and after 3 months of follow-up. CFR was measured noninvasively in left descending artery by transthoracic echocardiography. Results: Eighty-five patients had an abnormal CFR at baseline. At baseline patients with persistently normal CFR had higher wall motion score index (WMI), ejection fraction (EF) and S′ compared with patients with abnormal CFR. At follow-up patients with persistently normal CFR had higher WMI, EF, S′ and lower end-systolic diameter compared with patients with abnormal microcirculation. Performing univariate logistical regression baseline CFR (P = 0.004), S′ (P = 0.045) and abnormal glucose metabolism (P = 0.001) were predictors of a decreased CFR at 3 months of follow-up. In multivariate analyses abnormal glucose metabolism (OR: 5.3; 95%CI: 1.9-14.4; P = 0.001) remained a predictor of decreased CFR at follow-up, furthermore baseline CFR (OR: 0.5; 95%CI: 0.25-0.94; P = 0.032) and S′ (OR: 0.67; 95% CI: 0.47-0.94; P = 0.021) was predictors of decreased CFR. Finally, CFR was associated with a lower risk of cardiac events in patients with normal glucose metabolism (HR: 0.64; 95% CI: 0.22-1.9; P = 0.42) than in patients with abnormal glucose metabolism (HR: 2.9; 95% CI: 1.1-7.6; P = 0.03), suggesting significant effect modification (Pinteraction = 0.03). Conclusions: Abnormal glucose metabolism is associated with poorer recovery of microvascular integrity after AMI. In addition, there seem to exist a prognostic interaction between glucometabolic state and abnormal CFR.