Key role of postchallenge hyperglycemia for the presence and extent of coronary atherosclerosis: An angiographic study

[Diabetes mellitus, coronary artery disease and heart disease (Update 2023)]

Diabetes mellitus, cardiovascular disease and heart failure are interacting dynamically. Patients being diagnosed with cardiovascular disease should be screened for diabetes mellitus. Enhanced cardiovascular risk stratification based on biomarkers, symptoms and classical risk factors should be performed in patients with preexisting diabetes mellitus. In patients with previously diagnosed arterosclerotic cardiovascular disease an agent proven to reduce major adverse cardiovascular events or cardiovascular mortality is recommended.

Postprandial Glucose Spikes, an Important Contributor to Cardiovascular Disease in Diabetes?

Clinical trials investigating whether glucose lowering treatment reduces the risk of CVD in diabetes have thus far yielded mixed results. However, this doesn't rule out the possibility of hyperglycemia playing a major causal role in promoting CVD or elevating CVD risk. In fact, lowering glucose appears to promote some beneficial long-term effects, and continuous glucose monitoring devices have revealed that postprandial spikes of hyperglycemia occur frequently, and may be an important determinant of CVD risk. It is proposed that these short, intermittent bursts of hyperglycemia may have detrimental effects on several organ systems including the vasculature and the hematopoietic system collectively contributing to the state of elevated CVD risk in diabetes. In this review, we summarize the potential mechanisms through which hyperglycemic spikes may increase atherosclerosis and how new and emerging interventions may combat this.

Elevated 1-h postload plasma glucose levels identify coronary heart disease patients with greater severity of coronary artery lesions and higher risk of 1-year re-admission

OBJECTIVE

To investigate the relationship of 1-h postload plasma glucose during the oral glucose tolerance test with the severity of coronary artery lesions and risk of 1-year re-admission in coronary heart disease patients with normal glucose tolerance.

METHODS

A total of 266 consecutive coronary heart disease patients who underwent coronary angiography and had normal glucose tolerance confirmed by oral glucose tolerance test during hospitalization were prospectively enrolled and followed in two groups according to the 1-h postload plasma glucose cut-off point (1-h postload plasma glucose <155 mg/dL, n = 149 and 1-h postload plasma glucose ⩾155 mg/dL, n = 117). Angiographic severity was assessed by number of diseased vessels, lesion morphology and Gensini score. The risk of 1-year re-admission with adverse cardiovascular events after discharge was analysed.

RESULTS

Subjects with a 1-h postload plasma glucose ⩾155 mg/dL had higher incidence of multivessel disease and complex lesions, Gensini score and risk of 1-year re-admission than subjects with a 1-h postload plasma glucose <155 mg/dL (all p < 0.05). In the stepwise multivariate regression analysis, 1-h postload plasma glucose was the major determinant of the Gensini score. Subgroup analyses by sex showed that men with a 1-h postload plasma glucose ⩾155 mg/dL had higher incidence of complex lesions and risk of 1-year re-admission than men with a 1-h postload plasma glucose <155 mg/dL (all p < 0.05).

CONCLUSION

Coronary heart disease patients with normal glucose tolerance and elevated 1-h postload plasma glucose levels had a greater severity of coronary artery lesions and an increased risk of re-admission with adverse cardiovascular events, particularly in men.

Multi-pathway integrated adjustment mechanism of licorice flavonoids presenting anti-inflammatory activity

Glycyrrhiza, commonly known as licorice, is a herbal medicine that has been used for thousands of years. Licorice contains multiple flavonoids, which possess a variety of biological activities. On the basis of the anti-inflammatory effects of licorice flavonoids, the potential mechanism of action was investigated via a plasma metabolomics approach. A total of 9 differential endogenous metabolites associated with the therapeutic effect of licorice flavonoids were identified, including linoleic acid, sphingosine, tryptophanamide, corticosterone and leukotriene B4. Besides classical arachidonic acid metabolism, metabolism of sphingolipids, tryptophan and fatty acids, phospholipids synthesis, and other pathways were also involved. The multi-pathway integrated adjustment mechanism of licorice flavonoid action may reduce side effects in patients, along with any anti-inflammatory functions, which provides a foundation for identifying and developing novel, high-potential natural drugs with fewer side effects for clinical application.

[Diabetes mellitus, coronary artery disease und heart disease (Update 2019)]

Diabetes mellitus, cardiovascular disease and heart failure are interacting dynamically. Patients being diagnosed with cardiovascular disease should be screened for diabetes mellitus. Enhanced cardiovascular risk stratification based on biomarkers, symptoms and classical risk factors should be performed in patients with pre-existing diabetes mellitus. In patients with previously diagnosed arterosclerotic cardiovascular disease an agent proven to reduce major adverse cardiovascular events or cardiovascular mortality is recommended after therapy failure of metformin.

Genetics, coronary artery disease, and myocardial revascularization: will novel genetic risk scores bring new answers?

Both percutaneous coronary intervention (PCI) and coronary artery bypass graft surgery (CABG) are options for revascularization in multi-vessel coronary artery disease (CAD). However, the best form of revascularization remains controversial. Results from clinical trials (FREEDOM, SYNTAX, NOBLE, EXCEL) have identified factors related to CAD severity such as diabetes and SYNTAX score as indicators that patients may have better outcomes with CABG compared to PCI. Nevertheless, the discovery of other predictors of optimal revascularization therapy is necessary to improve decision-making and personalize the treatment of multi-vessel CAD. Genome-wide association studies have identified numerous previously unknown DNA variants that increase predisposition for CAD. Recently, a composite polygenic risk score has been developed to better assess the relative contribution of multiple SNPs and quantify overall genetic risk for CAD. High polygenic risk score is associated with increased coronary events and greater benefit from statin therapy in large observational studies. This effect is independent from traditional cardiovascular risk factors. At the same time, randomized clinical trials have shown that CAD severity is a determinant of optimal revascularization treatment. It remains unknown whether polygenic risk score is robustly associated with increased CAD severity at presentation, and whether this score can be used to identify patients who will show greater benefit from revascularization with CABG or with PCI.

Genetics of coronary artery disease: should they impact the choice of revascularization?

PURPOSE OF REVIEW

Patients with multivessel coronary artery disease (CAD) may undergo revascularization by either percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG). This review will discuss the use of polygenic risk scores for risk-stratification of patients with multivessel CAD in order to guide the choice of revascularization.

RECENT FINDINGS

A 57-single nucleotide polymorphism (SNP)-polygenic risk score can accurately risk-stratify patients with CAD and identify those who will receive greater benefit from statin therapy. The most recent genomic studies reveal 243 different SNPs are now significantly associated with CAD. Randomized clinical trials comparing PCI vs. CABG (FREEDOM, SYNTAX, NOBLE, EXCEL) have uncovered factors related to CAD severity (diabetes, SYNTAX score) are critical determinants of outcomes after revascularization.

SUMMARY

There is a need to discover predictors of outcomes after PCI vs. CABG to improve clinical decision-making in multivessel CAD. High polygenic risk score is associated with increased CAD severity and better outcomes with statin therapy. Randomized clinical trials indicate CAD severity is associated with better outcomes after CABG compared with PCI. Accordingly, polygenic risk score could also be associated with better outcomes after CABG vs. PCI and used to optimize revascularization for patients with multivessel CAD.

Peroxisome proliferator-activated receptor-γ polymorphism (rs1801282) is associated with obesity in Egyptian patients with coronary artery disease and type 2 diabetes mellitus

OBJECTIVE

Peroxisome Proliferator-Activated Receptor-γ (PPAR-γ) gene is one of the possible genes linking diabetes mellitus (DM) with coronary artery disease (CAD). The aim of this study is to clarify whether PPAR-γ Pro12Ala polymorphism is associated with the development of CAD in type 2 diabetic patients and to evaluate PPAR-γ Pro12Ala polymorphism genetic distribution in type 2 DM (T2DM) Egyptian subjects.

METHODS

PPAR-γ Pro12Ala polymorphism was determined by Real-Time PCR in serum of 405 subjects classified into 4 groups; T2DM patients (n = 105), T2DM with CAD (n = 100), CAD patients (n = 100) and healthy controls (n = 100).

RESULTS

The PPAR-γ Pro12Ala polymorphism was associated significantly with T2DM with CAD (group2) (OR = 3, 95% CI = (1.5-6); p = 0.001). In this study, T2DM with CAD complications carrying the PPAR-γ Pro12Ala polymorphism had higher BMI than those without the PPAR-γ Pro12Ala polymorphism (p < 0.0001). CAD patients carrying PPAR-γ Pro12Ala polymorphism had considerable insulin resistance features. Plasma paraoxanase 1(PON1) level was considerably reduced among our 3 studied groups in comparison to control group (p < 0.001).

CONCLUSIONS

PPAR-γ Pro12Ala polymorphism might represent a novel risk factor for CAD in T2DM.

Sex-dependent effects of diabetes mellitus on the revascularization rate in mid-term follow up of young patients with coronary artery disease

AIMS

We investigated the association between Type-2 diabetes mellitus (DM) and the need for revascularization at a 5-year follow-up of young coronary artery disease patients and the role of sex in this regard.

METHODS

Among 1121 young (males≤45, and females≤55years) patients (female: 49.7%) from Tehran Heart Center's Premature Coronary Atherosclerosis Cohort, 371(33.1%) had diabetes prior to angiography. Revascularization was considered as either percutaneous coronary intervention or coronary artery bypass graft surgery.

RESULTS

The mean follow-up duration was 57.67±22.43months. In the univariable analysis, diabetics were at a significantly higher risk of revascularization than nondiabetics (Sub-distributional Hazard Ratio [SHR]=1.843, P value<0.001). There was no association between DM and revascularization among men (SHR=1.232, P value=0.508). In contrast, women with DM had threefold more revascularization risk than women without DM (SHR=3.519, P value<0.001). After adjustment for confounding factors, the risk of revascularization in diabetics compared to nondiabetics increased to 2.139 fold (95% CI=1.473, 3.108) among the whole subjects, remained nonsignificant among men, and increased significantly to 3.725 fold (95% CI=2.067, 6.725) in women.

CONCLUSIONS

Our data showed that in women with premature CAD, but not in men, DM may have a significant role in emerging revascularization during a mean follow-up of 5years.

Postprandial Blood Glucose Outweighs Fasting Blood Glucose and HbA1c in screening Coronary Heart Disease

The objective of the present study is to assess the performance of fasting blood glucose (FBG), postprandial blood glucose (PBG), and glycated hemoglobin (HbA1c) as screening for coronary heart disease (CHD) in an inpatient population undergoing coronary angiography. 1852 consecutive patients scheduled for coronary angiography were classified into Normal Glucose Tolerance (NGT), Impaired Glucose Regulation (IGR), and diabetes, based on FBG, PBG, and HbA1c. Correlations of Gensini score with glucose metabolism and insulin resistance were analyzed. The associations between glycemic variables and Gensini score or the presence of CHD were analyzed by multiple linear regression and logistic regression, respectively. CHD was diagnosed in 488, 622, and 414 patients with NGT, IGR, and diabetes, respectively. Gensini score was positively correlated with FBG (r = 0.09, p < 0.01), PBG (r = 0.20, p < 0.01), and HbA1c (r = 0.19, p < 0.01). Gensini score was not correlated with fasting insulin (r = −0.081, p = 0.36), post-prandial insulin (r = −0.02, p = 0.61), or HOMAIR (r = −0.0059, p = 0.13). When FBG, PBG and HbA1c were pooled altogether, only PBG persisted in its association with Gensini score and the prevalence of CHD. The severity of CHD was associated with glucose rather than insulin resistance in this Chinese population. PBG was optimally correlated with the presence and severity of CHD.

The effects of linagliptin on endothelial function and global arginine bioavailability ratio in coronary artery disease patients with early diabetes: study protocol for a randomized controlled trial

BACKGROUND

Patients with type 2 diabetes (T2DM) are at increased risk for macrovascular events as well as for microvascular complications. There is evidence that in patients with coronary artery disease (CAD), about 35 % suffer from manifest T2DM. Early glucose-lowering intervention in subjects with T2DM has been demonstrated to be beneficial in terms of cardiovascular risk reduction. But thus far, no data are available regarding investigating the impact of linagliptin treatment in patients with early diabetes on cardiovascular endpoints or surrogate parameters. Therefore, the aim of this study is to investigate the effects of linagliptin in CAD patients with early T2DM on various cardiovascular surrogate measurements including mechanical and biochemical endothelial function assessments.

METHODS/DESIGN

Forty-two subjects with early diabetes and CAD are included in this investigator-driven, randomized, placebo-controlled, double-blind, phase IV, single-center study. Participants will be randomized to receive either linagliptin (5 mg) administered once daily per os or placebo for 12 weeks. Before and after the intervention, evaluation of endothelial function (flow-mediated dilatation and biochemical biomarkers) and a Meal Tolerance Test are performed.

DISCUSSION

Cardiovascular surrogate parameters, such as endothelial function, are able to provide insights into the potential mechanisms of the cardiovascular effects of antihyperglycemic agents. Currently ongoing trials do not specifically focus on early diabetes as a target of intervention and we therefore believe that our study will contribute to a better understanding of the cardiovascular effects of dipeptidylpeptidase-4 (DPP-4) inhibitors in early diabetes.

TRIAL REGISTRATION

NCT02350478 . Registered 26 January 2015. Protocol date/version 24 October 2014/version 2.4 EudraCT number: 2013-000330-35.

Prevalence of type 2 diabetes is higher in peripheral artery disease than in coronary artery disease patients

Type 2 diabetes mellitus and pre-diabetes are risk factors for atherosclerosis and are highly prevalent in patients with coronary artery disease. However, the prevalence of impaired glucose metabolism in patients with peripheral artery disease is not as well elucidated. We aimed at comparing prevalence rates of type 2 diabetes mellitus and pre-diabetes, which were diagnosed according to the current American Diabetes Association criteria, among 364 patients with peripheral artery disease, 529 patients with coronary artery disease and 383 controls. The prevalence of type 2 diabetes mellitus in peripheral artery disease patients was 49.7%. It was significantly higher in these patients than in coronary artery disease patients (34.4%; p < 0.001) and controls (21.4%; p < 0.001). Adjusted for sex, age and body mass index, odds ratios for type 2 diabetes mellitus were 2.0 (95% confidence interval 1.5-2.6) comparing the peripheral artery disease group with the coronary artery disease group (p < 0.001) and 4.0 (2.8-5.8) comparing the peripheral artery disease group with controls (p < 0.001). The prevalence of pre-diabetes among non-diabetic subjects was high in all three study groups (64.5% in peripheral artery disease patients, 63.4% in coronary artery disease patients and 61.8% in controls), without significant between-group differences. In conclusion, the prevalence of type 2 diabetes mellitus is even higher in peripheral artery disease patients than in coronary artery disease patients. This observation underlines the need to consider impaired glucose regulation in the management of peripheral artery disease.

Characteristics of Patients With Diabetes Having Normal Coronary Arteries

We evaluated the association between risk variables in diabetic patients with normal and diseased coronary arteries in a retrospective cohort study conducted at Rashid Hospital, Dubai. A total of 4446 patients underwent coronary angiography due to various indications; 43% had type 2 diabetes mellitus (T2DM). Among the diabetic patients, 94% had diseased coronary arteries and the remaining 6% had absolutely normal arteries. The normal coronary group had significantly lower low-density lipoprotein cholesterol (LDL-C) and a higher high-density lipoprotein cholesterol (HDL-C) levels than the diseased group. Patients with normal coronaries were more likely to be females, have T2DM for a shorter duration, and were nonsmokers and non-South Asians. They also had lower levels of LDL, hemoglobin A1c, and fasting glucose and higher levels of HDL-C. Apart from these variables, genetic or environmental factors could protect these patients from atherosclerosis.

The relationship between glycated hemoglobin and complexity of coronary artery lesions among older patients with diabetes mellitus

Objectives

Glycated hemoglobin (HbA1c) is associated with an increased risk of cardiovascular disease. The aim of this study was to examine the relationship between HbA1c levels and the complexity of coronary artery lesions among the older patients with diabetes mellitus (DM).

Methods

This retrospective study enrolled a total of 3805 consecutive type 2 DM patients aged 60 years and older who underwent their first elective coronary angiography and had their HbA1c levels measured at the Chinese PLA General Hospital between December 2005 and December 2012.The complexity of the coronary artery lesions was evaluated using the Syntax score, and the subjects were divided into three groups according to their HbA1c levels. Logistic regression and Pearson correlation were used to analyze the association between the measured HbA1c levels and Syntax score.

Results

The mean age was 72.3±10.6 years. The higher HbA1c levels were significantly associated with higher Syntax score (p<0.001). The unadjusted correlation coefficient of HbA1c levels and the Syntax score was 0. 371 (p<0.001). In addition, the higher HbA1c categories were able to independently predict patients with intermediate or high Syntax score (Syntax score ≥23) after adjustment for age, sex, hypertension, smoking, dyslipidemia and creatinine levels in the logistic regression analysis.

Conclusion

HbA1c is significantly associated with the complexity of coronary lesions among older patients with DM. A higher HbA1c value is an independent predictor of the prevalence of complex coronary lesions. Further prospective multi-centre studies are needed to confirm this finding.

Stress hyperglycaemia in hospitalized patients with coronary artery disease and type 2 diabetes risk

AIMS

(i) To evaluate glucometabolic status of patients without known diabetes hospitalized due to coronary artery disease (CAD), (ii) to assess markers of systemic inflammation determined during admission and to evaluate their relationship with glucometabolic status and (iii) to analyse usefulness of HbA1c determined during admission in patients with CAD to detect abnormal glucose regulation (AGR).

MATERIALS & METHODS

We studied 440 patients with CAD admitted to the cardiology ward. Patients were grouped in four groups during admission according to clinical data, fasting plasma glucose and HbA1c: diabetes, HbA1c > 5·9%, stress hyperglycaemia (SH) and normal. In 199 subjects without known diabetes, an oral glucose tolerance test (OGTT) was performed 3 months after discharge, and they were reclassified according to WHO 1998 criteria. Biochemical and inflammatory markers were measured.

RESULTS

The OGTT showed that 27·4% of subjects without known diabetes at admission had diabetes, 11·2% had impaired fasting glucose + impaired glucose tolerance, 33·5% impaired glucose tolerance, 3·6% impaired fasting glucose, and 24·4% normal glucose metabolism. Odds ratio for having diabetes 3 months after discharge in HbA1c > 5·9% group was 5·91 (P < 0·0001) and in SH group was 1·82 (P = 0·38). The best HbA1c cut-off point to predict AGR was 5·85%. HbA1c levels during admission were highly predictive of having AGR (AUC ROC 0·76 [95% CI 0·67-0·84]).

CONCLUSION

We reported a high prevalence of AGR in subjects with CAD. Stress hyperglycaemia in patients with CAD was not associated with an increased risk of diabetes 3 months later. HbA1c in patients hospitalized with CAD was a useful tool to detect AGR.

EGCG attenuates high glucose-induced endothelial cell inflammation by suppression of PKC and NF-κB signaling in human umbilical vein endothelial cells

AIMS

Vascular inflammation is a key factor in the pathogenesis of diabetes-related vascular complications. Our previous study showed that (-)-epigallocatechin-3-gallate (EGCG) inhibits high glucose-induced vascular smooth muscle cell proliferation, thus it may have beneficial effects in diabetes and its complications. However, the effect of EGCG on inflammation in diabetes is not known. In the present study, we investigated whether EGCG suppresses the vascular inflammation induced by high glucose in human umbilical vein endothelial cells (HUVECs).

MAIN METHODS

The inhibitory effect of EGCG on high glucose-induced up-regulation of the expression of vascular cell adhesion molecule 1 (VCAM-1) was measured using enzyme-linked immunosorbent, RT-PCR, immunoblotting and cell adhesion assays. The effect of EGCG on high glucose-induced nuclear factor-kappa B (NF-κB) activation was investigated by immunoblotting, immunofluorescence and electrophoretic mobility shift assays.

KEY FINDINGS

High glucose increased VCAM-1 expression and enhanced the adhesion of monocytes to HUVECs. Pretreatment with EGCG in a concentration-dependent manner (1.0-50 μM) significantly attenuated these effects. High glucose (25 mM)-mediated vascular inflammation was blocked by PKC pseudosubstrate (PKC inhibitor 19-31) or the NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC). Stimulation with high glucose increased the NF-κB translocation from the cytoplasm to the nucleus, and increased IκB-α phosphorylation, decreased its expression, and in the presence of EGCG, the effect of high glucose on NF-κB and IκB-α were blocked.

SIGNIFICANCE

EGCG suppresses high glucose-induced vascular inflammatory process via the inhibition of PKC and NF-κB activation in HUVECs, suggesting that EGCG may be a potential candidate for the treatment and prevention of diabetic vascular complications.

The relationship between coronary risk factors and elevated 1-h postload plasma glucose levels in patients with established coronary heart disease

OBJECTIVE

Recent studies have shown that an elevated 1-h postload plasma glucose (1hPG) is able to identify subjects with normal glucose tolerance (NGT) at high risk for future type 2 diabetes and atherosclerotic cardiovascular disease. However, clinical studies about the characteristics of coronary heart disease (CHD) patients with elevated 1hPG are lacking. The aim of this study was to analyse the 1hPG level in CHD patients with NGT.

METHODS

A total of 204 CHD patients with NGT were recruited. Subjects underwent an oral glucose tolerance test, echocardiography and coronary angiography. Demographic data were recorded and blood samples obtained. According to the 1hPG cut-off point of 8.6 mm, patients were divided into two groups: 1hPG ≥ 8.6 mm (n = 65) and 1hPG < 8.6 mm (n = 139).

RESULTS

Compared with the 1hPG < 8.6 mm group, subjects with 1hPG ≥ 8.6 mm had a worse metabolic profile, exhibiting significantly higher body mass index, systolic blood pressure, triglyceride level and lower HDL-cholesterol level. Plasma high-sensitivity CRP (hsCRP) levels were higher in the 1hPG ≥ 8.6 mm group than in the 1hPG < 8.6 mm group. Coronary angiography revealed that single-vessel changes were more frequent in the 1hPG < 8.6 mm group, but there were no significant differences in the Gensini score.

CONCLUSIONS

Patients with CHD with 1hPG ≥ 8.6 mm have a worse metabolic profile, higher levels of hsCRP and multi-vessel coronary atherosclerosis. These findings suggest that, in patients with CHD, elevated 1hPG increases coronary risk factors and may be a marker for early-stage glucose intolerance.

Assessment and treatment of cardiovascular risk in prediabetes: impaired glucose tolerance and impaired fasting glucose

Individuals with impaired glucose tolerance (IGT) and/or impaired fasting glucose (IFG) are at high risk, not only to develop diabetes mellitus, but also to experience an adverse cardiovascular (CV) event (myocardial infarction, stroke, CV death) later in life. The underlying pathophysiologic disturbances (insulin resistance and impaired β-cell function) responsible for the development of type 2 diabetes are maximally/near maximally expressed in subjects with IGT/IFG. These individuals with so-called prediabetes manifest all of the same CV risk factors (dysglycemia, dyslipidemia, hypertension, obesity, physical inactivity, insulin resistance, procoagulant state, endothelial dysfunction, inflammation) that place patients with type 2 diabetes at high risk for macrovascular complications. The treatment of these CV risk factors should follow the same guidelines established for patients with type 2 diabetes, and should be aggressively followed to reduce future CV events.

A progressive increase in cardiovascular risk assessed by coronary angiography in non-diabetic patients at sub-diabetic glucose levels

OBJECTIVE

Diabetes mellitus type 2 (DM2) is a risk factor for coronary heart disease (CHD). While there is a clear correlation of fasting blood glucose (FBG) and 2 h post-challenge blood glucose values (2h-BG) with microvascular complications, the risk for CHD conferred by glucose dysregulation antecedent to DM2 is less clear. Therefore, we investigated associations of FBG and 2h-BG values with the prevalence of CHD assessed by coronary angiography as the most sensitive diagnostic tool.

RESEARCH DESIGN AND METHODS

Coronary angiography was performed in 1394 patients without known DM. Capillary blood glucose was analyzed before and 2 h after an oral glucose tolerance test. Associations between FBG as well as 2h-BG levels and the risk for CHD were assessed by logistic regression analysis.

RESULTS

1064 (75%) of patients were diagnosed with CHD. 204 (15%) were diagnosed with so far unknown DM2, 274 (20%) with isolated impaired fasting glucose (IFG), 188 (13%) with isolated impaired glucose tolerance (IGT) and 282 (20%) with both, IGT and IFG. We found a continuous increase in the risk for CHD with fasting and post-challenge blood glucose values even in the subdiabetic range. This correlation did however not suggest clear cut-off values. The increase in risk for CHD reached statistical significance at FBG levels of > 120 mg/dl (Odds Ratio of 2.7 [1.3-5.6] and 2h-BG levels > 140 mg/dl (141-160 mg/dl OR 1.8 [1.1-2.9], which was however lost after adjusting for age, sex and BMI.

CONCLUSIONS

In our study population we found a continuous increased risk for CHD at fasting and 2h-BG levels in the sub-diabetic glucose range, but no clear cut-off values for cardiovascular risk.

Arginine bioavailability ratios are associated with cardiovascular mortality in patients referred to coronary angiography

OBJECTIVES

Arginine is the only source for nitric oxide (NO) synthesis. The bioavailability of NO plays a pivotal role in endothelial function and consequently in cardiovascular disease. The aim of the current study is to investigate the association of arginine bioavailability ratios with markers of endothelial function and cardiovascular mortality in patients referred to coronary angiography.

METHODS

We investigated 2236 patients recruited within the LUdwigshafen RIsk and Cardiovascular Health (LURIC) study that were followed up for a median of 7.7 years. Arginine, ornithine and citrulline were chromatographically determined after precolumn-derivatisation followed by postcolumn continuous reaction with ninhydrin. Global arginine bioavailability (GABR) was calculated by arginine divided by the sum of ornithine plus citrulline.

RESULTS

We observed a significant rise in cardiovascular mortality with decreasing GABR and arginine to ornithine ratio quartiles. The adjusted Cox proportional HRs for GABR were 1.27 (0.88-1.83), 1.27 (0.89-1.80) and 1.75 (1.24-2.45) for the 3rd, the 2nd and the 1st quartile respectively in comparison to the 4th quartile. The HRs for the quartiles of the arginine to ornithine ratio were 1.83 (1.25-2.67), 2.17 (1.50-3.20) and 2.02 (1.39-2.92) respectively. Patients with type 2 diabetes mellitus had a significantly lower GABR than persons without diabetes (0.88 ± 0.23 vs. 0.94 ± 0.24, p<0.001). GABR was found to be inversely correlated with endothelial markers as VCAM-1 (r=-0.301, p<0.001) or ICAM-1 (r=-0.136, p<0.001).

CONCLUSIONS

GABR and the arginine to ornithine ratio are associated with markers of endothelial dysfunction and increased risk of cardiovascular mortality. Further studies are warranted to elucidate the pathobiology and clinical relevance of the arginine bioavailability ratios in cardio-metabolic diseases.

Relation of albuminuria to angiographically determined coronary arterial narrowing in patients with and without type 2 diabetes mellitus and stable or suspected coronary artery disease

Albuminuria is associated with atherothrombotic events and all-cause mortality in patients with and without diabetes. However, it is not known whether albuminuria is associated with atherosclerosis per se in the same manner. The present study included 914 consecutive white patients who had been referred for coronary angiography for the evaluation of established or suspected stable coronary artery disease (CAD). Albuminuria was defined as a urinary albumin/creatinine ratio ≥ 30 μg/mg. Microalbuminuria was defined as 30 to 300 μg albumin/mg creatinine, and macroalbuminuria as a urinary albumin/creatinine ratio of ≥ 300 μg/mg. The prevalence of stenoses of ≥ 50% was significantly greater in patients with albuminuria than in those with normoalbuminuria (66% vs 51%; p <0.001). Logistic regression analysis, adjusted for age, gender, diabetes, smoking, hypertension, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, C-reactive protein, body mass index, estimated glomerular filtration rate, and the use of angiotensin-converting enzyme inhibitors/angiotensin II antagonists, aspirin, and statins, confirmed that albuminuria was significantly associated with stenoses ≥ 50% (standardized adjusted odds ratio [OR] 1.68, 95% confidence interval [CI] 1.15 to 2.44; p = 0.007). The adjusted OR was 1.54 (95% CI 1.03 to 2.30; p = 0.034) for microalbuminuria and 2.55 (95% CI 1.14 to 5.72; p = 0.023) for macroalbuminuria. This association was significant in the subgroup of patients with type 2 diabetes (OR 1.66, 95% CI 1.01 to 2.74; p = 0.045) and in those without diabetes (OR 1.42, 95% CI 1.05 to 1.92; p = 0.023). An interaction term urinary albumin/creatinine ratio*diabetes was not significant (p = 0.579). In conclusion, micro- and macroalbuminuria were strongly associated with angiographically determined coronary atherosclerosis in both patients with and those without type 2 diabetes mellitus, independent of conventional cardiovascular risk factors and the estimated glomerular filtration rate.

Glucometabolic state in Chinese patients undergoing elective coronary angiography

AIM

The aim of this study is to characterize the glucometabolic state of patients undergoing elective coronary angiography (CA) in a subpopulation in China.

METHODS AND RESULTS

This study recruited 896 patients undergoing elective CA for the evaluation of suspected coronary artery disease (CAD). Oral glucose tolerance tests (OGTTs) performed in patients without previously known diabetes revealed that 173 (19.2%) had newly diagnosed diabetes and 281 (31.5%) had impaired glucose regulation. The prevalence of abnormal glucose metabolism (AGM) was significant difference among three groups of CA diagnosis, including normal coronary, nonsignificant stenosis and CAD. Overall, the proportion of patients with type 2 diabetes increased from 22.0% at baseline to 41.2% post-OGTT analysis. In total, 270 (59.5%) patients with AGM would have remained undetected if OGTTs had not been performed. Patients with CAD, hypertension, dyslipidemia, obesity and high C-reactive protein levels were at high risk of AGM.

CONCLUSIONS

AGM is common and underestimated by FPG testing alone in patients undergoing elective CA. OGTTs should be routinely performed to assess the glucometabolic state of patients undergoing elective CA, especially in patients with high risks of AGM. Detecting the state of AGM in CA individuals may provide strategies to reduce the progression of AGM and associated complications.

Low bone mineral density is not associated with angiographically determined coronary atherosclerosis in men

This study for the first time investigates the association of bone mineral density (BMD) with angiographically determined coronary atherosclerosis in men. Our data show that the prevalence of low BMD is very high in men undergoing coronary angiography. However, neither osteopenia nor osteoporosis is associated with an increased prevalence of angiographically determined coronary atherosclerosis.

INTRODUCTION

The association of low BMD with angiographically determined coronary atherosclerosis in men is unknown.

METHODS

We enrolled 623 consecutive men undergoing coronary angiography for the evaluation of established or suspected coronary artery disease (CAD). BMD was assessed by dual X-ray absorptiometry. CAD was diagnosed in the presence of any coronary artery lumen narrowing at angiography; coronary stenoses with lumen narrowing > or =50% were considered significant.

RESULTS

From the total study cohort (mean age of 64 +/- 11 years), 207 patients (33.2%) had osteopenia and 65 (10.4%) had osteoporosis; at angiography, CAD was diagnosed in 558 patients (89.6%) and 403 (64.7%) had significant coronary stenoses. In multivariate logistic regression analysis neither osteopenia nor osteoporosis was associated with an increased prevalence of CAD (adjusted odds ratios (ORs) = 0.71 [95% confidence interval 0.40-1.23]; p = 0.222 and 1.03 [0.38-2.80]; p = 0.955, respectively) or with significant coronary stenoses (OR 0.74 [0.52-1.07], p = 0.112 and 0.72 [0.41-1.26]; p = 0.251, respectively). Also, as a continuous variable, BMD was not associated with angiographically diagnosed CAD.

CONCLUSIONS

The prevalence of low BMD is very high in men undergoing coronary angiography. However, low BMD is not associated with angiographically determined coronary atherosclerosis in men.

Progression of coronary artery disease during long-term follow-up of the Swiss Interventional Study on Silent Ischemia Type II (SWISSI II)

BACKGROUND

This study evaluates cardiovascular risk factors associated with progression of coronary artery disease (CAD) in patients with silent ischemia following myocardial infarction.

HYPOTHESIS

Coronary artery disease only progresses slowly with comprehensive risk factor intervention.

METHODS

A total of 104 of 201 patients (51.7%) of the Swiss Interventional Study on Silent Ischemia Type II (SWISSI II) with baseline and follow-up coronary angiography were included. All patients received comprehensive cardiovascular risk factor intervention according to study protocol. Logistic regression was used to evaluate associations between baseline cardiovascular risk factors and CAD progression.

RESULTS

The mean duration of follow-up was 10.3+/-2.4 years. At baseline, 77.9% of patients were smokers, 45.2% had hypertension, 73.1% had dyslipidemia, 7.7% had diabetes, and 48.1% had a family history of CAD. At last follow-up, only 27 patients of the initial 81 smokers still smoked, only 2.1% of the patients had uncontrolled hypertension, 10.6% of the patients had uncontrolled dyslipidemia, and 2.1% of the patients had uncontrolled diabetes. Coronary artery disease progression was found in up to 81 (77.9%) patients. Baseline diabetes and younger age were associated with increased odds of CAD progression. The time interval between baseline and follow-up angiography was also associated with CAD progression.

CONCLUSION

Coronary artery disease progression was highly prevalent in these patients despite comprehensive risk factor intervention. Further research is needed to optimize treatment of known risk factors and to identify other unknown and potentially modifiable risk factors.

PPARgamma gene C161T substitution alters lipid profile in Chinese patients with coronary artery disease and type 2 diabetes mellitus

Background

Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated transcription factor, which regulates gene expression of the key proteins involved in lipid metabolism, vascular inflammation, and proliferation. PPARγ may contribute to attenuating atherogenesis and postangioplasty restenosis. PPARγ C161→T substitution is associated with a reduced risk of coronary artery disease (CAD). Whether or not the gene substitution alters the risk of CAD in type 2 diabetes mellitus (T2DM) patients remains unclear.

Methods

A total of 556 unrelated subjects from a Chinese Han population, including 89 healthy subjects, 78 CAD patients, 86 T2DM patients, and 303 CAD combined with T2DM patients, were recruited to enroll in this study. PPARγC161→T gene polymorphism was determined by polymerase chain reaction and restriction fragment length polymorphisms. Plasma levels of lipoproteins, apolipoproteins, glucose, and insulin were measured by ELISA or radioimmunoassay (RIA). The coronary artery lesions were evaluated by coronary angiography.

Results

The frequency of the 161T allele in CAD, T2DM, and CAD combined with T2DM patients was similar to that observed in the healthy control group. However, in CAD combined with T2DM patients, the group with angiographically documented moderate stenoses had a higher frequency of the 161T allele in comparison to the group with severe stenoses (P < 0.05). Moreover, in CAD with T2DM patients, the triglyceride levels and apoB in CC homozygote carriers were significantly higher than those in "T" allele carriers.

Conclusions

PPARγC161→T genotypes weren't significantly associated with the risk of CAD, but were markedly correlated with severity of disease vessels in patients with CAD and T2DM. Furthermore, PPARγC161→T substitution was associated with an altered adipose, but not glucose metabolism. These results indicate that the PPARγ C161→T polymorphism may reduce the risk of severe atherogenesis by modulation of adipose metabolism, especially triglycerides and apoB, in Chinese patients with CAD and T2DM.

Coronary angiographic studies of impaired glucose regulation and coronary artery disease in Chinese nondiabetic subjects

To investigate the prevalence and the extent of coronary artery disease (CAD) in nondiabetic Chinese patients with different categories of impaired glucose regulation (IGR): isolated impaired fasting glucose (I-IFG); isolated impaired glucose tolerance (I-IGT); and combined IFG and IGT (CGI). A total of 556 nondiabetic subjects who had undergone coronary angiography were included in this study. Subjects were classified according to the 75-g oral glucose tolerance test result: normal glucose tolerance (NGT) (n = 278), I-IFG (n = 52), I-IGT (n = 128), CGI (n = 98). Significant CAD is defined as the presence of one or more coronary vessels with the lumeninal reduction in diameter to ≥50% in a given subject. The severity and extent of coronary atherosclerosis are defined by the Gensini score, the worst artery score, and the number of diseased vessels with significant coronary stenosis (number of diseased vessels). The prevalence of significant CAD in I-IFG and I-IGT groups were similar (67.3%, P = 0.207; 67.4%, P = 0.068, respectively) but both were higher comparing with NGT group (57.9%), however, it was considerably higher in CGI group (85.9%, P < 0.001). The Gensini score, worst artery score, and number of diseased vessels were similar in NGT, I-IFG, and I-IGT groups, but all significantly increased in CGI group after adjustment for other traditional factors (all P < 0.001). Logistic regression analyses reveal fasting glucose but not 2-h glucose as a significant determinant in Gensini score, worst artery score, and number of diseased vessels. The prevalence and the extent of CAD did not differ significantly among subjects with NGT, I-IFG, and I-IGT, but increased significantly in those with CGI. Fasting glucose was more strongly associated with angiographically characterized coronary artery stenosis than 2-h glucose.

Metabolic syndrome defined by IDF and AHA/NHLBI correlates better to carotid intima-media thickness than that defined by NCEP ATP III and WHO

AIMS

We conducted this study to compare the relationships between subclinical atherosclerosis and metabolic syndrome (MS) defined by four definitions in Chinese subjects.

METHODS

In 2006-2007, we enrolled 140 Chinese subjects without reported diabetes in this study. Anthropometric, biochemical profile, and carotid intima-media thickness (IMT) were measured. MS was defined by International Diabetes Federation (IDF), American Heart Association and the National Heart, Lung, and Blood Institute (AHA/NHLBI), National Cholesterol Education Program Adult Treatment Panal III (NCEP-ATP III), and World Health Organization (WHO) criteria.

RESULTS

Subjects with MS defined by IDF and AHA/NHLBI criteria had significantly higher carotid IMT, controlling for age, gender, smoking, and serum LDL-C (MS by IDF, partial r=0.225, p=0.008; AHA/NHLBI, partial r=0.176, p=0.04). The association between carotid IMT and MS defined by NCEP-ATP III or WHO criteria was not significant. Subjects with more components of MS defined by IDF, AHA/NHLBI, or NCEP-ATP III criteria correlated to higher carotid IMT in adjusted models (p-values for trend, MS by IDF, 0.011; AHA/NHLBI, 0.011; NCEP-ATPIII, 0.01; WHO, 0.113).

CONCLUSION

MS definitions by IDF and AHA/NHLBI criteria are the best among four definitions in detecting subclinical atherosclerosis in non-diabetic Chinese subjects; whereas MS defined by WHO criteria is the worst.

Systemic correlates of angiographic coronary artery disease

Coronary angiography allows a direct evaluation of coronary anatomy. The aim of the present investigation was to search for correlations between the magnitude of coronary artery disease, as assessed by angiography, and a number of systemic parameters. A group of 116 patients (80 male, 36 female) with coronary heart disease diagnosed by angiography, aged 62.0±10.5 years, was the subject of an observational study. Correlation and linear regression analysis using coronary artery disease burden (CADB - sum of the percentage of the luminal stenosis encountered in all the lesions of the coronary arterial trees) as dependent variable, and age, sex, plasma calcium, phosphorus, magnesium, glucose, HDL cholesterol, LDL cholesterol, triglycerides, uric acid, estimated glomerular filtration rate and body mass index as independent variables, were carried out. Significant correlation values versus CADB were seen with age (r 0.19, p 0.04), uric acid (r 0.18, p 0.048) and fasting plasma glucose (r 0.33, p<0.001). Linear regression analysis, yielding a global significance level of 0.002, showed a significant value for glucose (p 0.018) and for sex (0.008). In conclusion, among several systemic parameters studied, plasma glucose was found to be correlated to coronary artery atherosclerosis lesions.

Fine-tuning of prediction of isolated impaired glucose tolerance: a quantitative clinical prediction model

In this cross-sectional study, we evaluated results of oral glucose tolerance test (OGTT) from 4742 women and 3470 men, participated in the Tehran Lipid and Glucose Study, aged >or=20 years and without diabetes, to determine the diagnostic value of subjects' clinical traits with isolated impaired glucose tolerance (isolated-IGT) defined as fasting plasma glucose (FPG) <5.6 mmol/L and 2-h plasma glucose between 7.8 and 11.1 mmol/L. The overall prevalence of IGT was 13.6% (n=1120); of these subjects, 59.6% (n=668) had isolated-IGT. The adjusted odds ratios for having isolated-IGT among 7012 subjects with FPG <5.6 mmol/L were significant for age >or=40 years (2.5), hypertension (1.9), abnormal waist circumference (1.9), obesity (1.5), and family history of diabetes (1.3). Adding the lipid profiles to the clinical model increased the area under the ROC curve only slightly (73.2% vs. 72.1%, respectively; P=0.002). In summary, this study showed that in adults with FPG <5.6 mmol/L, older age, family history of diabetes, abnormal waist circumference and obesity, and hypertension were significantly associated with a higher likelihood of isolated-IGT; OGTT could hence be recommended in subjects who have most of these characteristics to find Isolated-IGT, especially if the findings are supported by appropriately designed clinical trials.