Editorial: Hyperglycemia and Coronary Artery Diseases: Physio-Pathological Findings and Therapeutic Implications

Many observational studies have documented that hyperglycemia frequently occurs among patients hospitalized with the acute coronary syndrome (ACS) and without diabetes mellitus (Capes et al., 2000; Kosiborod et al., 2005; Ferreira et al., 2021). Epidemiological studies showed that 25–50% of ACS patients had elevated blood glucose levels at admission (Deedwania et al., 2008). Why are we concerned by these observations? Because several studies have shown that acute hyperglycemia at admission (AH) is independently associated with a poor early and late prognosis in ACS patients, especially those diagnosed with acute myocardial infarction (AMI) (Deedwania et al., 2008). In particular, high glucose levels at admission increased the intra-hospital mortality by twice compared to normoglycemic diabetic patients and 3.9-fold vs. normoglycemic patients without diabetes (Capes et al., 2000). Thus, AH in ACS is an independent risk factor for cardiovascular mortality, especially in patients without known diabetes. Which blood glucose levels affect the ACS outcomes? To date, despite numerous studies regarding hyperglycemia during cardiovascular events have been published, there’s not a clear definition for AH in the setting of ACS. Most early studies defined hyperglycemia by the first available glucose value or admission blood glucose levels (Capes et al., 2000; Kosiborod et al., 2005; Deedwania et al., 2008; Ferreira et al., 2021). Nevertheless, the cutpoint of AH used to define hyperglycemia in patients with ACS was different from study to study. However, the most acceptable description of AH refers to the first acquired blood glucose within 24 h of admission (Kojima et al., 2020). Back in 2008, the American Heart Association Scientific (AHA) Statement on Hyperglycemia and Acute Coronary Syndrome suggested using an ABG level >140mg/dL as the definition of hyperglycemia under such circumstances irrespective of fasting status (Deedwania et al., 2008). Therefore, it is essential to know what occurs in the heart when blood glucose rises to more than 140mg/dl during ACS. In this context, hyperglycemia may exacerbate acute cardiac disease in various ways, including compounding microvascular obstruction (Sardu et al., 2019a), attenuating endothelium-dependent vasodilation (D’Onofrio et al., 2016), impairing platelet nitric oxide responsiveness and endothelial repair (Marchetti et al., 2006; Balestrieri et al., 2013), increasing coronary thrombosis (Menghini et al., 2014), and promoting direct cardiomyocyte damage (D’Onofrio et al., 2020). Thus, hyperglycemia may be responsible for both coronary and cardiomyocytes impairments. The inflammatory burden in the peri-infarct region is associated with worse shortand mid-term outcomes because the inflammatory response in this region probably may amplify myocardial necrosis. In this context, hyperglycemic stress during ACS is associated with increased levels of some inflammatory markers, including C-reactive protein and interleukin-18, and enhanced expression of Edited and reviewed by: Konrad Urbanek, Magna Græcia University of Catanzaro, Italy