The Significance of Dynamics of ST Segment Changes When Assessing the Effectiveness of Mechanical Reperfusion of the Myocardium in Hyperglycaemic Patients with Acute Myocardial Infarction with Persistent ST-Segment Elevation

Abstract

Background: The coexistence of coronary heart disease and consequently, acute myocardial infarction with persistent ST-segment elevation (STEMI) and glucose metabolism disorders is well known. Still, glucose metabolism disorders in the STEMI population are not fully understood. We know that diabetes mellitus (DM) is a factor disabling the function of microcirculation, which in turn may affect the outcome of coronary intervention. The aim of this study was to evaluate the dynamics of ST-segment changes in ECG (electrocardiogram) in STEMI (ST-segment elevation myocardial infarction) patients with co-existing hyperglycaemia compared to those with normoglycaemia treated with a percutaneous coronary intervention (PCI), as well as to determine this parameter in the assessment of reperfusion effectiveness. Methods: The study included 92 patients with the diagnosis of STEMI enrolled in the PCI treatment and was divided into groups based on the glucose levels on admission (reactive hyperglycaemia): a group with higher glucose levels on admission (Glc ≥ 7.8 mmol/L, n = 46), a group with lower glucose levels on admission (Glc < 7.8 mmol/L, n = 46) and into groups based on the concentration of HbA1c: a group with a lower HbA1c level (<6.5% (48 mmol/mol), n=71) and a group with a higher level (≥6.5%, n=21). Results: On admission, there were no significant differences in terms of clinical characteristics between the groups of patients with normoglycemia and reactive hyperglycaemia. After PCI, the patients with normoglycemia had significantly higher (p = 0.021) dynamics of changes in the resolution of ST-segment elevation in ECG expressed in an indicator of sum STR (resolution of ST-elevation). A degree of resolution of ST elevation in ECG was significantly (p = 0.021) dependent on the level of blood glucose – higher the blood glucose level, weaker the resolution. The patients with glucose levels ≥7.8 mmol/L had significantly higher levels of CK and CK-MB during the first 48 hours of hospitalization. There was a statistically significant difference in the mean length of hospitalization between individuals from the group with lower and higher blood glucose levels on admission (p = 0.028). A 4-month follow-up revealed no significant difference in the incidence of major adverse cardiovascular events (MACE) in the study groups (p = 0.063). A 4-year follow-up of patients with higher levels of blood glucose on admission showed a higher incidence of MACE (p = 0.01). The patients with HbA1c ≥ 6.5% were older (p = 0.004), had a greater BMI > 30kg/m2 (p=0.019) and the lower ejection fraction of the left ventricle (p = 0.003) compared to those with the HbA1c levels <6.5%. The incidence of MACE in 4-month and 4-year follow-up was comparable in the study population.