Clinical impact of acute hyperglycemia on development of diabetes mellitus in non-diabetic patients with acute myocardial infarction

Predictors of Carbohydrate Metabolism Disorders and Lethal Outcome in Patients after Myocardial Infarction: A Place of Glucose Level

BACKGROUND AND AIM

The aim of this study was to reveal statistical patterns in patients with acute myocardial infarction (AMI) that cause the development of carbohydrate metabolism disorders (CMD) (type 2 diabetes mellitus and prediabetes) and death within 5 years after AMI.

METHODS

1079 patients who were treated with AMI in the Almazov National Medical Research Center were retrospectively selected for the study. For each patient, all data from electronic medical records were downloaded. Statistical patterns that determine the development of CMDs and death within 5 years after AMI were identified. To create and train the models used in this study, the classic methods of Data Mining, Data Exploratory Analysis, and Machine Learning were used.

RESULTS

The main predictors of mortality within 5 years after AMI were advanced age, low relative level of lymphocytes, circumflex artery lesion, and glucose level. Main predictors of CMDs were low basophils, high neutrophils, high platelet distribution width, and high blood glucose level. High values of age and glucose together were relatively independent predictors. With glucose level >11 mmol/L and age >70 years, the 5-year risk of death is about 40% and it rises with increasing glucose levels.

CONCLUSION

The obtained results make it possible to predict the development of CMDs and death based on simple parameters that are easily available in clinical practice. Glucose level measured on the 1st day of AMI was among the most important predictors of CMDs and death.

Basic types of the first-day glycemia in acute myocardial infarction: Prognostic, diagnostic, threshold and target glycemia

We described the importance of stress hyperglycemia (SH) in critical illnesses and their evaluation in the emergency department (ED) and coronary care unit (CCU). Hyperglycemia is found in over half of the patients with suspected acute myocardial infarction (AMI). SH can be used for several purposes in AMI. Receiver operating characteristic curves are needed to find optimal cut-offs to divide blood glucose levels associated with good from bad prognosis in AMI. There is a need for a consensus for pragmatic classification of first day glycemia in order to be useful in a busy ED and CCU.

Stress-Induced Hyperglycaemia in Non-Diabetic Patients with Acute Coronary Syndrome: From Molecular Mechanisms to New Therapeutic Perspectives

Stress-induced hyperglycaemia (SIH) at hospital admission for acute coronary syndrome is associated with poor outcome, especially in patients without known diabetes. Nevertheless, insulin treatment in these subjects was not correlated with the reduction of mortality. This is likely due to the fact that SIH in the context of an acute coronary syndrome, compared to that in known diabetes, represents an epiphenomenon of other pathological conditions, such as adrenergic and renin-angiotensin system over-activity, hyperglucagonaemia, increase of circulating free fatty acids and pancreatic beta-cell dysfunction, which are not completely reversed by insulin therapy and so worsen the prognosis. Thus, SIH may be considered not only as a biomarker of organ damage, but also as an indicator of a more complex therapeutic strategy in these subjects. The aim of this review is to analyse the molecular mechanisms by which SIH may favour a worse prognosis in non-diabetic patients with acute coronary syndrome and identify new therapeutic strategies, in addition to insulin therapy, for a more appropriate treatment and improved outcomes.

Impact of Hyperglycemia on Long-Term Outcome in Patients With ST-Segment Elevation Myocardial Infarction

In patients with ST-segment elevation myocardial infarction (STEMI), the association between stress-induced hyperglycemia (SIH) and long-term outcomes, as well as the effects of baseline diabetic status on this association remain elusive. To clarify the association between SIH and long-term outcomes, and the effects of baseline diabetic status on this association, we studied 6,287 STEMI patients who were discharged alive. SIH was estimated using the stress hyperglycemia ratio (SHR), which is defined as [(admission glucose (mg/dl))/(28.7 × HbA1c (%) - 46.7)]. End points were all-cause death and admission for heart failure (HF). We compared prognosis between patients in the highest SHR quartile and those in other quartiles of the nondiabetic and diabetic population. Over a follow-up of 5 years (median 1,522 days), 464 (7.4%) and 401 (6.4%) cases of all-cause death and HF admission were observed. In the nondiabetic population, the highest SHR quartile (Q4) group was significantly associated with worse long-term outcomes (adjusted hazard ratio [HR] (95% confidence interval [CI]), all-cause death; 1.45 (1.06 to 1.98), p = 0.021, HF admission; 1.48 (1.04 to 2.10), p = 0.031). However, in the diabetic population, SHR Q4 group was not significantly associated with worse long-term outcomes (adjusted HR (95% CI), all-cause death; 1.00 (0.68 - 1.48), p = 0.996, HF admission; 1.31 (0.90 to 1.89), p = 0.154). In conclusion, in STEMI patients discharged alive, high SHR was significantly associated with worse long-term prognosis in the nondiabetic population. In contrast, high SHR was not significantly associated with worse long-term prognosis in the diabetic population.

Melatonin rescues cardiac thioredoxin system during ischemia-reperfusion injury in acute hyperglycemic state by restoring Notch1/Hes1/Akt signaling in a membrane receptor-dependent manner

Stress hyperglycemia is commonly observed in patients suffering from ischemic heart disease. It not only worsens cardiovascular prognosis but also attenuates the efficacies of various cardioprotective agents. This study aimed to investigate the protective effect of melatonin against myocardial ischemia-reperfusion (MI/R) injury in acute hyperglycemic state with a focus on Notch1/Hes1/Akt signaling and intracellular thioredoxin (Trx) system. Sprague Dawley rats were subjected to MI/R surgery and high-glucose (HG, 500 g/L) infusion (4 mL/kg/h) to induce temporary hyperglycemia. Rats were treated with or without melatonin (10 mg/kg/d) during the operation. Furthermore, HG (33 mmol/L)-incubated H9c2 cardiomyoblasts were treated in the presence or absence of luzindole (a competitive melatonin receptor antagonist), DAPT (a γ-secretase inhibitor), LY294002 (a PI3-kinase/Akt inhibitor), or thioredoxin-interacting protein (Txnip) adenoviral vectors. We found that acute hyperglycemia aggravated MI/R injury by suppressing Notch1/Hes1/Akt signaling and intracellular Trx activity. Melatonin treatment effectively ameliorated MI/R injury by reducing infarct size, myocardial apoptosis, and oxidative stress. Moreover, melatonin also markedly enhanced Notch1/Hes1/Akt signaling and rescued intracellular Trx system by upregulating Notch1, N1ICD, Hes1, and p-Akt expressions, increasing Trx activity, and downregulating Txnip expression. However, these effects were blunted by luzindole, DAPT, or LY294002. Additionally, Txnip overexpression not only decreased Trx activity, but also attenuated the cytoprotective effect of melatonin. We conclude that impaired Notch1 signaling aggravates MI/R injury in acute hyperglycemic state. Melatonin rescues Trx system by reducing Txnip expression via Notch1/Hes1/Akt signaling in a membrane receptor-dependent manner. Its role as a prophylactic/therapeutic drug deserves further clinical study.

Proposal of a New Approach to Study and Categorize Stress Hyperglycemia in Acute Myocardial Infarction

BACKGROUND

Stress hyperglycemia (SH) is a valid prognosticator of in-hospital complications and mortality in the intensive care unit, and is universally available, simple, and cost-effective. Even small refinements of SH can improve the risk stratification of patients with one of the most important diseases today-acute myocardial infarction (AMI).

OBJECTIVE

The aim of the review was to analyze whether SH nomenclature and methodology have been consistent in the medical literature in order to identify possible methodological faults and to suggest possible solutions.

DISCUSSION

SH nomenclature and glycemic targets have been relatively uniform in recent years, but there has been a pronounced variability in the methodology. Recent meta-analysis showed that AMI patients with new hyperglycemia had a 3.6-fold increased risk of mortality during hospitalization in comparison to those who were normoglycemic. Four SH methodological mistakes were identified. First, using one cutoff value for SH instead of two different values (one for patients with diabetes mellitus [DM] and one for patients without DM). Second, analyzing, for example, either tertiles or quintiles without dividing AMI patients into subgroups according to their DM status. Third, studying only two subgroups (with SH and without SH), without determining the presence of DM, when DM is not analyzed. Fourth, failure to measure glycated hemoglobin.

CONCLUSIONS

The same admission blood glucose (BG) is a marker of different mortality risks in diabetic compared to nondiabetic AMI patients. For example, when admission BG is 108-126 mg/dL (6-7 mmol/L), then the risk of in-hospital mortality is higher in DM patients; however, with an admission BG of 162-180 mg/dL (9-10 mmol/L), the risk is lower in diabetic patients. We can improve the clinical utility of the admission BG in AMI if we analyze four groups of patients (those with and without previously diagnosed DM, and above and below the admission glycemia cutoff values for in-hospital mortality). Those cutoffs should be calculated separately for diabetic and nondiabetic AMI patients.

Interaction of β1-adrenoceptor with RAGE mediates cardiomyopathy via CaMKII signaling

Stimulation of β1-adrenergic receptor (β1AR), a GPCR, and the receptor for advanced glycation end-products (RAGE), a pattern recognition receptor (PRR), have been independently implicated in the pathogenesis of cardiomyopathy caused by various etiologies, including myocardial infarction, ischemia/reperfusion injury, and metabolic stress. Here, we show that the two distinctly different receptors, β1AR and RAGE, are mutually dependent in mediating myocardial injury and the sequelae of cardiomyopathy. Deficiency or inhibition of RAGE blocks β1AR- and RAGE-mediated myocardial cell death and maladaptive remodeling. Ablation or blockade of β1AR fully abolishes RAGE-induced detrimental effects. Mechanistically, RAGE and β1AR form a complex, which in turn activates Ca²⁺/calmodulin-dependent kinase II (CaMKII), resulting in loss of cardiomyocytes and myocardial remodeling. These results indicate that RAGE and β1AR not only physically crosstalk at the receptor level, but also functionally converge at the common mediator, CaMKII, highlighting a combined inhibition of RAGE and β1AR as a more effective therapy to treat diverse cardiovascular diseases, such as myocardial infarction, ischemia/reperfusion injury, and diabetic cardiovascular complications.

Subclinical elevation of high-sensitive troponin T levels at the convalescent stage is associated with increased 5-year mortality after ST-elevation myocardial infarction

BACKGROUND

It is unclear whether serum high-sensitive troponin T (hs-TnT) levels at the convalescent stage of ST-elevation myocardial infarction (STEMI) are associated with long-term mortality.

METHODS

This study enrolled a total of 2944 consecutive STEMI patients who were registered in the Osaka Acute Coronary Insufficiency Study between 2000 and 2009, and whose hs-TnT levels were evaluated at the convalescent stage. Patients were divided into four hs-TnT category groups according to the results of survival classification and regression tree (CART) analysis. The impact of hs-TnT levels on 5-year mortality was evaluated using multivariate Cox regression analysis.

RESULTS

Only one patient had hs-TnT level below the detection limit of the assay (<0.003ng/mL). The median hs-TnT level was 0.025 (quartile 0.011-0.083)ng/mL. During the median follow-up period of 1782 days, 188 patients died. Survival CART analysis revealed that the 1st, 2nd, and 3rd discriminating hs-TnT levels to discern 5-year mortality were 0.028, 0.008, and 1.340ng/mL, respectively. The adjusted hazard ratios for the medium-low (0.009-0.028ng/mL), medium-high (0.029-1.340ng/mL), and high-risk (≥1.341ng/mL) groups were 3.03 (95% confidence interval 1.18-7.77, p=0.021), 4.29 (1.63-11.28, p=0.003), and 8.68 (2.20-34.27, p=0.002), respectively. Integrated discrimination improvement (IDI) analysis revealed that incorporation of this hs-TnT classification scheme with other clinical variables statistically improved the discriminatory accuracy for 5-year mortality, with a time-dependent IDI of 0.0076 (p=0.033).

CONCLUSIONS

hs-TnT levels at the convalescent stage were associated with long-term mortality in STEMI patients. Even subclinical elevation of hs-TnT levels was associated with increased 5-year mortality.

Reduced risk of recurrent myocardial infarction in homozygous carriers of the chromosome 9p21 rs1333049 C risk allele in the contemporary percutaneous coronary intervention era: a prospective observational study

OBJECTIVES

Chromosome 9p21 single nucleotide polymorphism (SNP) is a susceptibility variant for acute myocardial infarction (AMI) in the primary prevention setting. However, it is controversial whether this SNP is also associated with recurrent myocardial infarction (ReMI) in the secondary prevention setting. The purpose of this study is to evaluate the impact of chromosome 9p21 SNP on ReMI in patients receiving secondary prevention programmes after AMI.

DESIGN

A prospective observational study.

SETTING

Osaka Acute Coronary Insufficiency Study (OACIS) in Japan.

PARTICIPANTS

2022 patients from the OACIS database.

INTERVENTIONS

Genotyping of the 9p21 rs1333049 variant.

PRIMARY OUTCOME MEASURES

ReMI event after survival discharge for 1 year.

RESULTS

A total of 43 ReMI occurred during the 1 year follow-up period. Although the rs1333049 C allele had an increased susceptibility to their first AMI in an additive model when compared with 1373 healthy controls (OR 1.20, 95% CI 1.09 to 1.33, p=2.3*10(−4)), patients with the CC genotype had a lower incidence of ReMI at 1 year after discharge of AMI (log-rank p=0.005). The adjusted HR of the CC genotype as compared with the CG/GG genotypes was 0.20 (0.06 to 0.65, p=0.007). Subgroup analysis demonstrated that the association between the rs1333049 CC genotype and a lower incidence of 1 year ReMI was common to all subgroups.

CONCLUSIONS

Homozygous carriers of the rs1333049 C allele on chromosome 9p21 showed a reduced risk of 1 year ReMI in the contemporary percutaneous coronary intervention era, although the C allele had conferred susceptibility to their first AMI.