Acute hyperglycemia causes microvascular damage, leading to poor functional recovery and remodeling in patients with reperfused ST-segment elevation myocardial infarction.

Background: Although acute hyperglycemia (AHG) is associated with poor outcomes in ST-segment elevation myocardial infarction (STEMI) patients, underlying mechanisms have not been fully elucidated. We investigated the influence of AHG on myocardial microcirculation in reperfused STEMI patients.
Methods and Results: Thirty-four STEMI patients were divided into 2 groups according to the presence (Group H, n 5 11) or the absence (Group L, n 5 23) of AHG. Myocardial blood flow (MBF) and myocardial flow reserve (MFR) in the infarct-related area were compared between 2 groups, using ¹³N-ammonia positron emission tomography. Wall motion abnormality scores (WMASs) and end-diastolic volume indices (EDVI) were also assessed at 1 and 6 months after the onset. Although resting MBF was similar, MFR was lower in Group H than in Group L (1.69 ± 0.37 vs 2.39 ± 0.56, P = .001). WMAS was greater in Group H than in Group L at both 1 month (7.4 ± 3.7 vs 3.7 ± 3.0, P = .011) and 6 months (7.3 ± 3.9 vs 3.1 ± 3.4, P = .015). EDVI tended to be greater in Group H than in Group L at 6 months (103.8 ± 42.9 vs 73.9 ± 16.0 mL/m2, P = .071). Multivariate analysis showed AHG to be independently associated with low MFR.
Conclusions: In STEMI patients, AHG impaired myocardial microcirculation, leading to poor functional recovery and remodeling despite successful reperfusion.