Riobaldo M.R. Cintra

Glycosylated hemoglobin is associated with decreased endothelial function, high inflammatory response, and adverse clinical outcome in non-diabetic STEMI patients.

OBJECTIVE Chronic dysglycemia was recently identified as a predictor for adverse outcomes in patients with ST-elevation myocardial infarction (STEMI) treated by percutaneous coronary intervention. Data for non-diabetic patients who underwent thrombolysis is scarce. In this context, we aimed to study the effect of HbA1c on cardiovascular outcome after STEMI. METHODS A prospective cohort of 326 non-diabetic STEMI individuals was used for the analyses. We measured plasma glucose, hemoglobin A1c [HbA1c], lipid profile, C-reactive protein (CRP), and nitrate/nitrite (NOx) upon admission and five days after STEMI (D5). Flow-mediated dilation (FMD) was performed 30 days after STEMI. During clinical follow-up, we assessed patients for incident diabetes (progression to HbA1c ≥ 6.5%) and major adverse cardiac events (MACE), defined as a composite of fatal and non-fatal MI, sudden cardiac death, and angina requiring hospitalization. RESULTS Using ROC-curve analysis, a 5.8% HbA1c best predicted MACE with a sensitivity of 75% and specificity of 53% (AUC 0.673, p = 0.001). Patients were categorized as high HbA1c if ≥ 5.8% and low HbA1c if <5.8%. Compared with patients with low HbA1c, those with high HbA1c presented with 20% higher CRP-D5 (p = 0.009) and 19% higher ΔCRP (p = 0.01), a 32% decrease in ΔNOx (p < 0.001), and 33% lower FMD (p < 0.001). After a median follow-up of 1.9 (1.1-2.8) years, patients with high HbA1c had more incident diabetes (HR 2.3 95% CI 1.01-5.2; p = 0.048) and MACE (HR 3.32 95% CI 1.09-10.03; p = 0.03). CONCLUSION Non-diabetic STEMI patients with high HbA1c present with decreased endothelial function and increased inflammatory response and long-term risk of MACE.

Validation of surrogate indexes of insulin sensitivity in acute phase of myocardial infarction based on euglycemic-hyperinsulinemic clamp

The decrease in insulin sensitivity (IS) during myocardial infarction (MI) is recognized as a possible contributor to poor patient outcomes. Despite its potential relevance, a standardized and convenient IS assessment tool has yet to be established for said clinical scenarios. This study aimed to validate the accuracy of surrogate indexes in determining IS in acute MI patients by comparison with the gold standard reference method for measuring IS, the euglycemic-hyperinsulinemic clamp (EHC). We performed EHCs in 31 consecutive nondiabetic patients who were admitted within the first 24 h of symptoms of ST-segment elevation MI. Patients with prior diagnosis of diabetes, use of hypoglycemic agents, or a glycosylated hemoglobin ≥6.5% were excluded. EHCs were performed at the second day (D2) and sixth day (D6) post-MI. Basal (12-h fasting) blood samples from D2 and D6 were used to evaluate patient blood glucose and insulin levels. We then calculated the following surrogate indexes: homeostatic model assessment of insulin sensitivity (HOMA2S), homeostatic model assessment of insulin resistance (HOMA-IR), and quantitative insulin sensitivity check index (QUICKI). The IS index measured by EHC (ISiclamp) was correlated to HOMA2S, HOMA-IR, and QUICKI at D2 (r = 0.485, P = 0.009; r = -0.384, P = 0.048; r = 0.479, P = 0.01, respectively) and D6 (r = 0.621, P = 0.002; r = -0.576, P = 0.006; r = 0.626, P = 0.002, respectively). Receiver operator characteristic curves made for discrimination of ISiclamp above the median in D2 and D6 depicted areas under the curve of 0.740, 0.734, and 0.760 for HOMA2S, HOMA-IR, and QUICKI, respectively. Bland-Altman plots displayed no apparent systematic error for indexes, but a propensity for proportional error, particularly with HOMA-IR. Thus, based on EHC, these simple surrogate indexes are feasible for assessing IS during MI.

TCF7L2 polymorphism is associated with low nitric oxide release, endothelial dysfunction and enhanced inflammatory response after myocardial infarction

Backgound The favorable effects of insulin during myocardial infarction (MI) remain unclear due to the divergence between mechanistic studies and clinical trials of exogenous insulin administration. The rs7903146 polymorphism of the transcription factor 7-like 2 (TCF7L2) gene is associated with attenuated insulin secretion. Methods In non-diabetic patients with ST-elevation MI (STEMI), using such a model of genetically determined down-regulation of endogenous insulin secretion we investigated the change in plasma insulin, C-peptide, interleukin-2 (IL-2), C-reactive protein (CRP), and nitric oxide (NOx) levels between admission (D1) and the fifth day after MI (D5). Coronary angiography and flow-mediated dilation (FMD) were performed at admission and 30 days after MI, respectively. Homeostasis Model Assessment estimated insulin secretion (HOMA2%β) and insulin sensitivity (HOMA2%S). Results Although glycemia did not differ between genotypes, carriers of the T-allele had lower HOMA2%β and higher HOMA2%S at both D1 and D5. As compared with non-carriers, T-allele carriers had higher plasma IL-2 and CRP at D5, higher intracoronary thrombus grade, lower FMD and NOx change between D1 and D5 and higher 30-day mortality. Conclusion In non-diabetic STEMI patients, the rs7903146 TCF7L2 gene polymorphism is associated with lower insulin secretion, worse endothelial function, higher coronary thrombotic burden, and higher short-term mortality. General significance During the acute phase of MI, a lower capacity of insulin secretion may influence clinical outcome.

Adiponectin concentration data improve the estimation of atherosclerotic risk in normal and in overweight subjects

The combinations of adipokines and body mass parameters to estimate carotid atherosclerotic disease have not been completely delineated.

Adverse outcome has a U-shaped relation with acute phase change in insulin sensitivity after ST-Elevation Myocardial Infarction

BACKGROUND Although stress hyperglycemia after myocardial infarction (MI) is consistently associated with increased mortality, recent studies suggest that the addition of upstream markers of glucose metabolism may improve risk identification. Hence, our aim was to evaluate the association between insulin sensitivity changes during MI hospitalization and outcomes. METHODS A prospective cohort of 331 consecutive ST-Elevation MI (STEMI) patients without insulin provision therapy was used for the analyses. Blood samples were collected upon admission (D1) and after 5days (D5) of the inciting event. We measured blood glucose and insulin to estimate insulin sensitivity using the updated Homeostasis Model Assessment (HOMA2S). Patients were assessed for intra-hospital death and major adverse cardiac events (MACE) during follow-up. RESULTS HOMA2S was 62%±52% on D1 and 86%±57% on D5 (p<0.001). Total follow-up was a median of 2 (0.9-2.8) years and found a U-shaped relation between the change in HOMA2S from D1 to D5 (ΔHOMA2S) and major adverse cardiac events (MACE) (p=0.017). Fully adjusted cox-regression models showed that patients from T1 and T3 were about 2.5 times more prone to suffer from MACE than those in T2. Net Reclassification Index adding ΔHOMA2S as a categorical variable dichotomized as T2 and T1 or T3 to a model of GRACE risk score with glucose D1 yielded a better predictive model (0.184 [95% CI 0.124-0.264]; p=0.032). CONCLUSION A U-shaped curve describes the relation between insulin sensitivity change and MACE during acute phase STEMI and, thus indicating that acute dysglycemia must be appreciated in light of a time spectrum and insulin levels.

HDL size is more accurate than HDL cholesterol to predict carotid subclinical atherosclerosis in individuals classified as low cardiovascular risk

Background: Misclassification of patients as low cardiovascular risk (LCR) remains a major concern and challenges the efficacy of traditional risk markers. Due to its strong association with cholesterol acceptor capacity, high-density lipoprotein (HDL) size has been appointed as a potential risk marker. Hence, we investigate whether HDL size improves the predictive value of HDL-cholesterol in the identification of carotid atherosclerotic burden in individuals stratified to be at LCR. Methods and Findings: 284 individuals (40–75 years) classified as LCR by the current US guidelines were selected in a three-step procedure from primary care centers of the cities of Campinas and Americana, SP, Brazil. Apolipoprotein Bcontaining lipoproteins were precipitated by polyethylene glycol and HDL size was measured by dynamic light scattering (DLS) technique. Participants were classified in tertiles of HDL size (,7.57; 7.57–8.22; .8.22 nm). Carotid intima-media thickness (cIMT) ,0.90 mm (80 th percentile) was determined by high resolution ultrasonography and multivariate ordinal regression models were used to assess the association between cIMT across HDL size and levels of lipid parameters. HDLcholesterol was not associated with cIMT. In contrast, HDL size .8.22 nm was independently associated with low cIMT in either unadjusted and adjusted models for age, gender and Homeostasis Model Assessment 2 index for insulin sensitivity,

TCF7L2 POLYMORPHISM IS ASSOCIATED WITH INCREASED INTRA-HOSPITAL MORTALITY FOLLOWING MYOCARDIAL INFARCTION

Although insulin offers a wide array of positive effects on the cardiovascular system, the benefit of exogenous insulin infusion on outcome after myocardial infarction (MI) remains controversial. Recently, rs7903146, a variant of transcription factor 7-like 2 (TCF7L2) gene has been associated with