Non-invasive cardiac imaging techniques and vascular tools for the assessment of cardiovascular disease in type 2 diabetes mellitus

Aggravating effect of abnormal low-density protein cholesterol level on coronary atherosclerotic plaque in type 2 diabetes mellitus patients assessed by coronary computed tomography angiography

BACKGROUND

The abnormal low-density protein cholesterol (LDL-C) level in the development of atherosclerosis is often comorbid in individuals with type 2 diabetes mellitus(T2DM). This study aimed to investigate the aggravating effect of abnormal LDL-C levels on coronary artery plaques assessed by coronary computed tomography angiography (CCTA) in T2DM.

MATERIALS AND METHODS

This study collected 3439 T2DM patients from September 2011 to February 2022. Comparative analysis of differences in coronary plaque characteristics was performed for the patients between the normal LDL-C level group and the abnormal LDL-C level group. Factors with P < 0.1 in the univariable linear regression analyses were included in the multivariable linear stepwise regression.

RESULTS

A total of 2820 eligible T2DM patients were included and identified as the normal LDL-C level group (n = 973) and the abnormal LDL-C level group (n = 1847). Compared with the normal LDL-C level group, both on a per-patient basis and per-segment basis, patients with abnormal LDL-C level showed more calcified plaques, partially calcified plaques, low attenuation plaques, positive remodellings, and spotty calcifications. Multivessel obstructive disease (MVD), nonobstructive stenosis (NOS), obstructive stenosis (OS), plaque involvement degree (PID), segment stenosis score (SSS), and segment involvement scores (SIS) were likely higher in the abnormal LDL-C level group than that in the normal LDL-C level group (P < 0.001). In multivariable linear stepwise regression, the abnormal LDL-C level was validated as an independent positive correlation with high-risk coronary plaques and the degree and extent of stenosis caused by plaques (low attenuation plaque: β = 0.116; positive remodelling: β = 0.138; spotty calcification: β = 0.091; NOS: β = 0.427; OS: β = 0.659: SIS: β = 1.114; SSS: β = 2.987; PID: β = 2.716, all P value < 0.001).

CONCLUSIONS

Abnormal LDL-C levels aggravate atherosclerotic cardiovascular disease (ASCVD) in patients with T2DM. Clinical attention deserves to be caught by the tailored identification of cardiovascular risk categories in T2DM individuals and the achievement of the corresponding LDL-C treatment goal.

Relationship between Indices of Vascular Function and Presence of Overt Cardiovascular Disease among Persons with Poorly Controlled Type 2 Diabetes

The aim of this study was to assess the factors associated with impaired vascular function in patients with poorly controlled type 2 diabetes (DM2) with and without overt cardiovascular disease (CVD). Ninety-five patients with DM2 and poor glycemic control were recruited and divided into two groups: Group 1, with known CVD (n = 38), and Group 2, without CVD (n = 57). Patients in Group 2 were further subdivided into those with short (<5 years, group 2b) and long (>5 years, group 2a) diabetes duration. Subclinical markers of atherosclerosis were assessed. Glycemic control was similar in the two groups (HbA1c: 9.2% (1.5) vs. 9.4% (1.8), p = 0.44). In Group 1, lower FMD (3.13 (2.16)% vs. 4.7 (3.4)%, p < 0.05) and higher cIMT (1.09 (0.3) mm vs. 0.96 (0.2) mm, p < 0.05) was seen compared with Group 2, whereas PWV was similar (12.1 (3.4) vs. 11.3 (3.0) m/s, p = 0.10). Patients in Group 2b had significantly lower PWV and cIMT and higher FMD compared to Group 1 (p < 0.05). Among patients with poorly controlled T2D, more pronounced vascular dysfunction was present in those with overt macrovascular disease. In patients with T2D without known CVD, vascular dysfunction was associated with disease duration. The use of vascular indices for cardiovascular risk stratification in patients with T2D requires further study.

Treating Dyslipidemias in the Primary Prevention of Atherosclerotic Cardiovascular Disease in Older Adults with Diabetes Mellitus

People with diabetes mellitus (DM), especially those who are older, are at higher risk for premature morbidity and mortality related to atherosclerotic cardiovascular disease (ASCVD). Clinical practice guidelines recommend statin therapy for people with DM ages 40 to 75 years. The evidence for those greater than 75 years of age is relatively limited at present. Other health problems should be considered when planning ASCVD primary prevention in adults ages greater than 75 years with DM. Clinicians should discuss the risks and benefits of each plan with these patients and their caregivers.

Effects of Different Antidiabetic Medications on Endothelial Glycocalyx, Myocardial Function, and Vascular Function in Type 2 Diabetic Patients: One Year Follow-Up Study

Background: Poor glycaemic control affects myocardial function. We investigated changes in endothelial function and left ventricular (LV) myocardial deformation in poorly controlled type 2 diabetics before and after glycaemic control intensification. Methods: In 100 poorly-controlled diabetic patients (age: 51 ± 12 years), we measured at baseline and at 12 months after intensified glycaemic control: (a) Pulse wave velocity (PWV, Complior); (b) flow-mediated dilatation (FMD, %) of the brachial artery; (c) perfused boundary region (PBR) of the sublingual arterial micro-vessels (side-view dark-field imaging, Glycocheck); (d) LV global longitudinal strain (GLS), peak twisting (pTw), peak twisting velocity (pTwVel), and peak untwisting velocity (pUtwVel) using speckle tracking echocardiography, where the ratio of PWV/GLS was used as a marker of ventricular-arterial interaction; and (e) Malondialdehyde (MDA) and protein carbonyls (PCs) plasma levels. Results: Intensified 12-month antidiabetic treatment reduced HbA1c (8.9 ± 1.8% (74 ± 24 mmol/mol) versus 7.1 ± 1.2% (54 ± 14 mmol/mol), p = 0.001), PWV (12 ± 3 versus 10.8 ± 2 m/s), PBR (2.12 ± 0.3 versus 1.98 ± 0.2 μm), MDA, and PCs; meanwhile, the treatment improved GLS (−15.2 versus −16.9%), PWV/GLS, and FMD% (p < 0.05). By multi-variate analysis, incretin-based agents were associated with improved PWV (p = 0.029), GLS (p = 0.037), PBR (p = 0.047), and FMD% (p = 0.034), in addition to a reduction of HbA1c. The patients with a final HbA1c ≤ 7% (≤ 53 mmol/mol) had greater reduction in PWV, PBR, and markers of oxidative stress, with a parallel increase in FMD and GLS, compared to those who had HbA1c > 7% (> 53 mmol/mol). Conclusions: Intensified glycaemic control, in addition to incretin-based treatment, improves arterial stiffness, endothelial glycocalyx, and myocardial deformation in type 2 diabetes after one year of treatment.

Lipoprotein ratios are better than conventional lipid parameters in predicting arterial stiffness in young men

Although dyslipidemia is associated with cardiovascular disease, there are conflicting data about the role of serum lipids and their ratios in promoting arterial stiffness. The authors aimed to compare serum lipid profiles to predict arterial stiffness, which was assessed by brachial-ankle pulse wave velocity in young Chinese men. A total of 1015 participants aged 18 to 44 years without serious comorbidities were recruited for conventional detection. Anthropometrics, brachial-ankle pulse wave velocity, serum lipids, and other laboratory data were measured. Univariate analysis and multivariate logistic regression were performed to examine the relationship between serum lipid profiles and brachial-ankle pulse wave velocity. Participants with high brachial-ankle pulse wave velocity exhibited higher levels of total cholesterol, triglyceride (TG), low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol (HDL-C), total cholesterol/HDL-C, TG/HDL-C, low-density lipoprotein cholesterol/HDL-C, and non-HDL-C/HDL-C. The subsequent multivariable logistic regression showed that TG/HDL-C, total cholesterol/HDL-C, non-HDL-C/HDL-C, and TG significantly increased the risk for arterial stiffness after adjustment for confounding factors. Results indicate that lipid ratios are superior to conventional lipid parameters for predicting arterial stiffness in young men and that the TG/HDL-C ratio has the strongest association with arterial stiffness.

Screening for asymptomatic coronary artery disease in patients with type 2 diabetes mellitus

Diabetes is a very frequent disease and it is estimated that its prevalence will continuously increase during the next two decades. The arteriosclerotic process in diabetic patients progresses earlier and more diffusely, and it is more accelerated in the diabetic patient than in the overall population. In diabetic subjects, acute myocardial infarction (AMI) and stroke are the leading causes of death, but the presence of arterial disease is not always detected before the development of the acute arterial event. Several times, AMI is asymptomatic or present nonspecific symptoms, and it is the initial form of presentation of coronary artery disease causing an important delay in initiating cardiovascular treatment in these patients. The purpose of this review article is to discuss how to screen and early diagnose the presence of coronary artery disease in asymptomatic diabetic patients, based on new available diagnostic resources. Currently, the most recommended technique used for screening coronary artery disease in these patients is myocardial perfusion scintigraphy or stress echocardiography because of greater sensitivity and specificity in relation to the exercise test. However, technological advances have enabled the development of new imaging diagnostic methods that are less invasive than conventional coronary angiography, and which gradually gain importance in the diagnosis of coronary artery disease as they show higher effectiveness with lower invasiveness and risk. Arch Endocrinol Metab. 2016;60(2):143-51.

Visceral Adiposity is Preferentially Associated with Vascular Stiffness Rather than Thickness in Men with Type 2 Diabetes

Aim: Visceral fat accumulation is known to underlie the clustering of cardiovascular risk factors. However, it is not completely understood how visceral fat accumulation influences the development of cardiovascular disease. In this study, we investigated the clinical impact of visceral adiposity on vascular stiffness and thickness in patients with type 2 diabetes (T2D).

Methods: One hundred and sixty-one patients with T2D, including 92 men and 69 women, were included in this cross-sectional study. Visceral fat area (VFA) and subcutaneous fat area (SFA) were measured by dual bioelectrical impedance analysis. Stiffness parameter β and intima-media thickness (IMT) of the common carotid artery were measured by ultrasonography.

Results: The mean age and duration of diabetes in the study population were 61 years and 13.9 years, respectively. In men, VFA and waist circumference (WC) were positively correlated with stiffness parameter β, whereas body mass index (BMI), WC, and SFA were negatively correlated with IMT. In contrast, in women, none of the obesity-related indices were significantly correlated with stiffness parameter β or IMT. In multiple regression analyses, VFA as well as WC, BMI, and SFA were independently associated with stiffness parameter β after adjustment for age and other potential confounders in men but not in women. None of the obesity-related indices were independently associated with IMT for either sex.

Conclusion: In men with T2D, visceral adiposity is associated with carotid arterial stiffness but not thickness.

Prognostic value of coronary computed tomography angiography in diabetic patients without chest pain syndrome

AIMS

Diabetic patients with coronary artery disease (CAD) are often free of chest pain syndrome. A useful modality for non-invasive assessment of CAD is coronary computed tomography angiography (CTA). However, the prognostic value of CAD on coronary CTA in diabetic patients without chest pain syndrome is relatively unknown. Therefore, the aim was to investigate the long-term prognostic value of coronary CTA in a large population diabetic patients without chest pain syndrome.

METHODS

Between 2005 and 2013, 525 diabetic patients without chest pain syndrome were prospectively included to undergo coronary artery calcium (CAC)-scoring followed by coronary CTA. During follow-up, the composite endpoint of all-cause mortality, non-fatal myocardial infarction (MI), and late revascularization (>90 days) was registered.

RESULTS

In total, CAC-scoring was performed in 410 patients and coronary CTA in 444 patients (431 interpretable). After median follow-up of 5.0 (IQR 2.7-6.5) years, the composite endpoint occurred in 65 (14%) patients. Coronary CTA demonstrated a high prevalence of CAD (85%), mostly non-obstructive CAD (51%). Furthermore, patients with a normal CTA had an excellent prognosis (event-rate 3%). An incremental increase in event-rate was observed with increasing CAC-risk category or coronary stenosis severity. Finally, obstructive (50-70%) or severe CAD (>70%) was independently predictive of events (HR 11.10 [2.52;48.79] (P = .001), HR 15.16 [3.01;76.36] (P = .001)). Obstructive (50-70%) or severe CAD (>70%) provided increased value over baseline risk factors.

CONCLUSION

Coronary CTA provided prognostic value in diabetic patients without chest pain syndrome. Most importantly, the prognosis of patients with a normal CTA was excellent.

Holter monitoring for the screening of cardiac disease in diabetes mellitus: The non-invasive Holter monitoring observation of new cardiac events in diabetics study

We investigated the usefulness of Holter monitoring to detect cardiac disease and predict future cardiovascular risk in asymptomatic diabetic patients. This is a multi-centre, prospective study in 406 asymptomatic diabetic patients. They were categorized into three groups based on findings of Holter monitoring. A total of 377 met inclusion criteria and were classified as low (n = 172), moderate (n = 136) and high risk (n = 69). In total, 86 in moderate and 53 in high risk receive further evaluation. In total, 29 in moderate and 25 in high risk were diagnosed as cardiac disease and 12 required additional treatment, including coronary intervention. Over 1.8 years of mean follow-up, 11 (16.5 per 1000 person-years) experienced cardiovascular events. The cumulative incidence in moderate and high risk was higher than that in low risk (p = 0.029 and p = 0.014, respectively). Our study suggests that Holter monitoring may be a useful screening tool to detect cardiac disease and predict future cardiovascular risk in asymptomatic diabetic patients.

Serum leptin levels are independently related to the incidence of ischemic heart disease in a prospective study of patients with type 2 diabetes

Background

New and clinically useful markers of cardiovascular risk are of essence in type 2 diabetes since ischemic heart disease is a major cause of death in these patients.

Methods

We analyzed baseline data from 476 men and 244 women who participated in “Cardiovascular Risk factors in Patients with Diabetes -a Prospective study in Primary care” study. All participants had type 2 diabetes and were 55-66 years old at recruitment during year 2005 to 2008. Except for established traditional risk markers for vascular disease, we also estimated vascular complications non-invasively by performance of carotid-femoral pulse-wave velocity (PWV, with applanation-tonometry) and intima-media thickness of carotid arteries (IMT, with B-mode ultrasound). Patients were followed for incidence of ischemic heart disease mortality and morbidity until end of the year 2012, using the national Swedish Cause of Death and Hospitalization Registries.

Results

During the follow-up period of a median of 6 years 47 men and 10 women died or were hospitalized for ischemic heart disease including myocardial infarction. Leptin levels were positively related to the hazard ratio (HR) in men (HR for each log 10 unit 4.9, CI 1.99 to 11.8) and women (HR 11.5, CI 1.47 to 89.7). Leptin predicted ischemic heart disease independently of age, HbA1c, BMI, systolic blood pressure and LDL-cholesterol/HDL-cholesterol ratio (men: HR 12.9 CI 3.2-53, women: HR 19.9, CI 1.2-327) This finding of increased risk related to high leptin levels was also statistically significant when carotid-femoral PWV and IMT were both added to the equations in men (hazard ratio 9.2 CI 2.1-41).

Conclusions

Our data support the use of serum leptin in type 2 diabetes to add independent prognostic information in terms of ischemic heart disease when compared with traditional cardiovascular risk factors. In the men of the cohort this prognostic information was in addition also to data on IMT and PWV, two non-invasive measurements of the extent of vascular disease. The power to detect a similar relationship in women was less strong due to lower incidence of cardiovascular disease.

Trial registration

ClinicalTrials.gov: NCT01049737.

Laser speckle contrast imaging: age-related changes in microvascular blood flow and correlation with pulse-wave velocity in healthy subjects

In the cardiovascular system, the macrocirculation and microcirculation—two subsystems—can be affected by aging. Laser speckle contrast imaging (LSCI) is an emerging noninvasive optical technique that allows the monitoring of microvascular function and can help, using specific data processing, to understand the relationship between the subsystems. Using LSCI, the goals of this study are: (i) to assess the aging effect over microvascular parameters (perfusion and moving blood cells velocity, MBCV) and macrocirculation parameters (pulse-wave velocity, PWV) and (ii) to study the relationship between these parameters. In 16 healthy subjects (20 to 62 years old), perfusion and MBCV computed from LSCI are studied in three physiological states: rest, vascular occlusion, and post-occlusive reactive hyperaemia (PORH). MBCV is computed from a model of velocity distribution. During PORH, the experimental results show a relationship between perfusion and age (R(2) = 0.67) and between MBCV and age (R(2) = 0.72), as well as between PWV and age at rest (R(2) = 0.91). A relationship is also found between perfusion and MBCV for all physiological states (R(2) = 0.98). Relationships between microcirculation and macrocirculation (perfusion-PWV or MBCV-PWV) are found only during PORH with R(2) = 0.76 and R(2) = 0.77, respectively. This approach may prove useful for investigating dysregulation in blood flow.

A prospective observational study of all-cause mortality in relation to serum 25-OH vitamin D3 and parathyroid hormone levels in patients with type 2 diabetes

BACKGROUND

Low levels of vitamin D have been related to increased mortality and morbidity in several non-diabetic studies. We aimed to prospectively study relationships between serum 25-OH vitamin D3 (vitamin D) and of serum parathyroid hormone (PTH) to total mortality in type 2 diabetes. We also aimed to compare the levels of these potential risk-factors in patients with and without diabetes.

METHODS

The main study design was prospective and observational. We used baseline data from 472 men and 245 women who participated in the "Cardiovascular Risk factors in Patients with Diabetes-a Prospective study in Primary care" study. Patients were 55-66 years old at recruitment, and an age-matched non-diabetic sample of 129 individuals constituted controls for the baseline data. Carotid-femoral pulse-wave velocity (PWV) was measured with applanation-tonometry and carotid intima-media thickness (IMT) with ultrasound. Patients with diabetes were followed for all-cause mortality using the national Swedish Cause of Death Registry.

RESULTS

Levels of vitamin D were lower in patients with diabetes than in controls, also after correction for age and obesity, while PTH levels did not differ. Nine women and 24 men died during 6 years of median follow up of the final cohort (n = 698). Vitamin D levels were negatively related to all-cause mortality in men independently of age, PTH, HbA1c, waist circumference, 24-h systolic ambulatory-blood pressure (ABP) and serum-apoB (p = 0.049). This finding was also statistically significant when PWV and IMT were added to the analyses (p = 0.028) and was not affected statistically when medications were also included in the regression-analysis (p = 0.01). In the women with type 2 diabetes, levels of PTH were positively related with all-cause mortality in the corresponding calculations (p = 0.016 without PWV and IMT, p = 0.006 with PWV and IMT, p = 0.045 when also adding medications to the analysis), while levels of vitamin D was without statistical significance (p >0.9).

CONCLUSIONS

Serum vitamin D in men and serum PTH in women give prognostic information in terms of total-mortality that are independent of regular risk factors in addition to levels of ABP, IMT and PWV.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01049737.

The Role of MicroRNAs in Diabetic Complications-Special Emphasis on Wound Healing

Overweight and obesity are major problems in today’s society, driving the prevalence of diabetes and its related complications. It is important to understand the molecular mechanisms underlying the chronic complications in diabetes in order to develop better therapeutic approaches for these conditions. Some of the most important complications include macrovascular abnormalities, e.g., heart disease and atherosclerosis, and microvascular abnormalities, e.g., retinopathy, nephropathy and neuropathy, in particular diabetic foot ulceration. The highly conserved endogenous small non-coding RNA molecules, the micro RNAs (miRNAs) have in recent years been found to be involved in a number of biological processes, including the pathogenesis of disease. Their main function is to regulate post-transcriptional gene expression by binding to their target messenger RNAs (mRNAs), leading to mRNA degradation, suppression of translation or even gene activation. These molecules are promising therapeutic targets and demonstrate great potential as diagnostic biomarkers for disease. This review aims to describe the most recent findings regarding the important roles of miRNAs in diabetes and its complications, with special attention given to the different phases of diabetic wound healing.

Mean platelet volume is associated with myocardial perfusion defect in diabetic patients

Aim

Our aim was to evaluate whether there was a relationship between mean platelet volume and myocardial perfusion defect in diabetic patients using myocardial perfusion imaging.

Method

Forty-four diabetic patients with myocardial perfusion defect (group 1) and 44 diabetic patients without myocardial perfusion defect (group 2), matched for age and gender, were retrospectively examined. Levels of mean platelet volume (MPV) in the two groups were assessed.

Results

MPV was higher in group 1 than group 2 patients (8.76 ± 0.76 and 8.25 ± 0.78 fl), respectively, p = 0.003). Levels of glucose, triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, haemoglobin (Hb) and glycosylated haemoglobin (HbA_1c), and body mass index (BMI) in the two groups were not statistically significantly different. Multivariate logistic regression analyses showed that MPV was the only variable independently associated with myocardial perfusion defects (OR: 2.401, 95% CI: 1.298–4.440, p = 0.013).

Conclusion

This study showed that higher MPV was associated with myocardial perfusion defects. Higher MPV in diabetic patients was independently related to myocardial perfusion defects and may be an indicator of myocardial ischaemia.

Cardiovascular microRNAs: as modulators and diagnostic biomarkers of diabetic heart disease

Diabetic heart disease (DHD) is the leading cause of morbidity and mortality among the people with diabetes, with approximately 80% of the deaths in diabetics are due to cardiovascular complications. Importantly, heart disease in the diabetics develop at a much earlier stage, although remaining asymptomatic till the later stage of the disease, thereby restricting its early detection and active therapeutic management. Thus, a better understanding of the modulators involved in the pathophysiology of DHD is necessary for the early diagnosis and development of novel therapeutic implications for diabetes-associated cardiovascular complications. microRNAs (miRs) have recently been evolved as key players in the various cardiovascular events through the regulation of cardiac gene expression. Besides their credible involvement in controlling the cellular processes, they are also released in to the circulation in disease states where they serve as potential diagnostic biomarkers for cardiovascular disease. However, their potential role in DHD as modulators as well as diagnostic biomarkers is largely unexplored. In this review, we describe the putative mechanisms of the selected cardiovascular miRs in relation to cardiovascular diseases and discuss their possible involvement in the pathophysiology and early diagnosis of DHD.

Chronic Mild Hyperglycemia in GCK-MODY Patients Does Not Increase Carotid Intima-Media Thickness

Aim. GCK-MODY is an autosomal dominant form of diabetes caused by heterozygous mutations in the glucokinase gene leading to a lifelong mild hyperglycemia. The risk of macrovascular complications is considered low, but studies are limited. We, therefore, investigated the carotid intima-media thickness (CIMT) as an indicator of macrovascular complications in a group of patients with GCK-MODY. Methods. Twenty-seven GCK mutation carriers and 24 controls recruited among their first-degree relatives were compared, all aging over 35 years. The CIMT was tested using a high-resolution B-mode carotid ultrasonography. Medical history, anthropometry, and biochemical blood workup were obtained. Results. The mean CIMT was 0.707 ± 0.215 mm (mean ± SD) in GCK mutation carriers and 0.690 ± 0.180 mm in control individuals. When adjusted for age, gender, and family status, the estimated mean difference in CIMT between the two groups increased to 0.049 mm (P = 0.19). No difference was detected for other characteristics, with the exception of fasting blood glucose (GCK-MODY 7.6 mmol/L ± 1.2 (136.4 mg/dL); controls 5.3 mmol/L ± 0.3 (95.4 mg/dL); P < 0.0001) and glycated hemoglobin HbA1c (GCK-MODY 6.9% ± 1.0%, 52 mmol/mol ± 10; controls 5.7% ± 0.4%, 39 mmol/mol ± 3; P < 0.0001). The frequency of myocardial infarction and ischemic stroke did not differ between groups. Conclusion. Our data indicate that the persistent hyperglycemia in GCK-MODY is associated with a low risk of developing diabetic macrovascular complications.

Value of exercise tolerance testing in evaluation of diabetic patients presented with atypical chest discomfort

BACKGROUND

Coronary artery disease is the single most important cause of mortality and morbidity in diabetic patients. Electrocardiographic stress test is a non-invasive modality to screen significant coronary involvement in minimally symptomatic diabetics.

OBJECTIVES

We investigated the Positive Predictive Value (PPV) of this test in comparison with coronary angiography.

MATERIALS AND METHODS

130 diabetic patients with atypical chest discomfort were studied and tested using Exercise Tolerance Test (ETT) among which 100 cases showed positive results that further were studied invasively by selective coronary angiography.

RESULTS

The positive predictive value of ETT for diagnosis of Coronary Artery Disease (CAD)among diabetic patients presented with atypical chest discomfort was 77%.

CONCLUSION

We conclude that electrocardiographic stress test is a valuable inexpensive non-invasive screening test in diabetic patients with atypical chest discomfort.

Determinants of brachial-ankle pulse wave velocity in normotensive young adults with type 2 diabetes mellitus

Brachial-ankle pulse wave velocity (baPWV) is simple, noninvasive method which correlates well with arterial stiffness. Herein, we assessed the determinants of baPWV in normotensive young adults with type 2 diabetes. We retrospectively enrolled 103 consecutive type 2 diabetic patients aged between 30 and 39 yr who measured baPWV with noninvasive pulse wave analyzer. The anthropometric parameters, blood pressure, pulse rate, fasting plasma glucose, fasting insulin, fasting C-peptide, HbA1c, lipid profile, hs-CRP, albuminuria status, AST/ALT, γ-GTP were checked concurrently. Also, we investigated history of smoking, alcohol drinking and medications by questionnaire. We found that maximal baPWV was positively correlated with mean blood pressure (r = 0.404, P < 0.001), heart rate (r = 0.285, P = 0.004), AST (r = 0.409, P < 0.001), ALT (r = 0.329, P = 0.001), γ-GTP (r = 0.273, P = 0.006), Urine albumin/creatinine ratio (r = 0.321, P = 0.003). By multiple linear regression, mean blood pressure and heart rate were significantly associated with maximal baPWV in male and total group. In female group, mean blood pressure was the only variable associated with maximal baPWV. These factors can be surrogate markers of arterial stiffness in this population.

The distinctive nature of atherosclerotic vascular disease in diabetes: pathophysiological and morphological insights

As the incidence of diabetes mellitus continues to rise, parallel increases in the rates of diabetic atherosclerotic vascular disease are projected to impart major health and socioeconomic challenges for authorities worldwide. Diabetes results in a proatherogenic phenotype, manifesting in an accelerated, diffuse, polyvascular fashion. In this review, we highlight the pathophysiological and morphological hallmarks of diabetic atherosclerosis.

New insights into insulin resistance in the diabetic heart

Insulin resistance is a major characteristic of obesity and type 2 diabetes, and develops in multiple organs, including the heart. Compared with its role in other organs, the physiological role of insulin resistance in the heart is not well understood. The heart uses lipid as a primary fuel, but glucose becomes an important source of energy in ischemia. The impaired ability to utilize glucose might contribute to cell death and abnormal function in the diabetic heart. Recent discoveries regarding the role of inflammation, mitochondrial dysfunction and endoplasmic reticulum (ER) stress in obesity have advanced our understanding of how insulin resistance develops in peripheral organs. In this review, we examine these findings in relation to the diabetic heart to provide new insights into the mechanism of cardiac insulin resistance.

Subclinical atherosclerosis in a community-based elderly cohort: the Korean Longitudinal Study on Health and Aging

BACKGROUND

Early detection of atherosclerosis in elderly people is important because of high cardiovascular mortality. However, only few studies have evaluated the prevalence of subclinical atherosclerosis in Asian elderly people. We evaluated subclinical atherosclerosis using various methods in a population-based cohort study, the Korean Longitudinal Study on Health and Aging (KLoSHA).

METHODS

Subjects aged over 65 years without symptomatic chest pain were recruited for the KLoSHA in 2006 by random stratified sampling (439 men and 561 women). Anthropometrics, biochemical parameters, body composition, and abdominal fat by computed tomography (CT) were measured. Multidetector-row cardiac CT for coronary artery calcium score (CACS) and severity of stenosis, and carotid sonography for intima-media thickness (IMT) were used to detect subclinical atherosclerosis. Pulse wave velocity (PWV) and ankle-brachial index (ABI) were also measured.

RESULTS

The prevalence of subclinical atherosclerosis defined by coronary stenosis >50%, CACS >100, PWV >9m/s, carotid-IMT >0.8mm, or ABI <0.9 was 17.6%, 28.1%, 37.9%, 39.2%, and 29.6%, respectively. There were significant, but modest correlations among parameters. Although male sex, diabetes mellitus, hypertension, abnormal BMI, and higher insulin resistance were associated with subclinical atherosclerosis, older age was found to be the most robust predictor after controlling for multiple factors.

CONCLUSION

Our results suggest that proactive screening with multiple measurements in elderly subjects, particularly in men and those with diabetes mellitus or hypertension, may help to identify asymptomatic patient with atherosclerosis. Further studies exploring the predictive value of diagnostic tools can determine the most appropriate measurement for predicting future cardiovascular events.

Endothelial function and left ventricular remodeling in diabetic and non-diabetic patients after acute coronary syndrome

BACKGROUND

Endothelial dysfunction is an independent predictor of future cardiac events.

MATERIAL/METHODS

We evaluated the relationship between flow-mediated dilation (FMD) in brachial artery and coronary risk factors in 93 patients (70 males, mean age: 62 ± 8 years) with ACS treated with primary angioplasty (PCI). The patients were divided into 2 subgroups: 43 patients with diabetes mellitus type 2 (DM) and 50 non-diabetics (non-DM). Patients were examined on the 3rd day after ACS and after 6 months. FMD on the 3rd day were significantly lower in DM than in non-DM (5.8 ± 2.2% vs. 8.8 ± 4.9%, p=0.0007) and after 6 months (6.2 ± 2.6% vs. 9.4 ± 4.4%, p<0.0001). It was also observed that the improvement of FMD in both groups after a 6-month follow-up inversely correlated with the increase of left ventricular end-diastolic volume (LVEDV) (r=-0.41, p<0.001).

RESULTS

There was an inverse relationship between FMD and age (r=-0.26, p<0.01), BMI (r=-0.26, p<0,005), total cholesterol (r=-0.56, p<0.001) and LDL cholesterol (r=-0.53, p<0.001). There was no relationship between triglycerides, hypertension and history of smoking. In the DM group, FMD negatively correlated with HbA1c (r=-0.68, p<0.001). Restenosis rate was significantly higher in the DM group (19% vs. 6%, p<0.001) but there was no relationship between FMD and restenosis.

CONCLUSIONS

Impaired FMD is more significant in diabetics than in non-diabetic patients with ACS. Lack of improvement of FMD after acute coronary syndrome can be a predictor of detrimental left ventricular remodeling in patients with ACS.

Exercise treadmill test in detecting asymptomatic coronary artery disease in type 2 diabetes mellitus

BACKGROUND

The present study was designed to develop criteria for screening patients with type 2 diabetes mellitus (T2DM) for asymptomatic coronary artery disease (CAD).

METHODS

A total of 213 patients with T2DM without typical angina or chest pain were studied between 2002 and 2007. We also evaluated 53 patients with T2DM who had reported chest discomfort using an exercise treadmill test (ETT).

RESULTS

Thirty-one of the 213 asymptomatic patients had positive ETT results. We performed coronary angiography on 23 of the 31 patients with a positive ETT and found that 11 of them had significant coronary stenosis. The main differences between the patients with significant stenosis and those with a negative ETT were age (63.1±9.4 vs. 53.7±10.1 years, P=0.008) and duration of diabetes (16.0±7.5 vs. 5.5±5.7 years, P<0.001). The positive predictive value (PPV) of the ETT was calculated to be 47.8%. The PPV of the ETT increased to 87.5% in elderly patients (≥60 years) with a long duration of diabetes (≥10 years). The latter value is similar to that of patients with T2DM who presented with chest discomfort or exertional dyspnea. The PPV of the ETT in symptomatic patients was 76.9%.

CONCLUSION

In the interest of cost-effectiveness, screening for asymptomatic CAD could be limited to elderly patients with a duration of diabetes ≥10 years.

Characteristics of coronary artery disease in symptomatic type 2 diabetic patients: evaluation with CT angiography

BACKGROUND

Coronary artery disease (CAD) is a common and severe complication of type 2 diabetes mellitus (DM). The aim of this study is to identify the features of CAD in diabetic patients using coronary CT angiography (CTA).

METHODS

From 1 July 2009 to 20 March 2010, 113 consecutive patients (70 men, 43 women; mean age, 68 ± 10 years) with type 2 DM were found to have coronary plaques on coronary CTA. Their CTA data were reviewed, and extent, distribution and types of plaques and luminal narrowing were evaluated and compared between different sexes.

RESULTS

In total, 287 coronary vessels (2.5 ± 1.1 per patient) and 470 segments (4.2 ± 2.8 per patient) were found to have plaques, respectively. Multi-vessel disease was more common than single vessel disease (p < 0.001), and the left anterior descending (LAD) artery (35.8%) and its proximal segment (19.1%) were most frequently involved (all p < 0.001). Calcified plaques (48.8%) were the most common type (p < 0.001) followed by mixed plaques (38.1%). Regarding the different degrees of stenosis, mild narrowing (36.9%) was most common (p < 0.001); however, a significant difference was not observed between non-obstructive and obstructive stenosis (50.4% vs. 49.6%, p = 0.855). Extent of CAD, types of plaques and luminal narrowing were not significantly different between male and female diabetic patients.

CONCLUSIONS

Coronary CTA depicted a high plaque burden in patients with type 2 DM. Plaques, which were mainly calcified, were more frequently detected in the proximal segment of the LAD artery, and increased attention should be paid to the significant prevalence of obstructive stenosis. In addition, DM reduced the sex differential in CT findings of CAD.

The association of brachial-ankle pulse wave velocity with 30-minute post-challenge plasma glucose levels in korean adults with no history of type 2 diabetes

Background

Acute postprandial hyperglycemia is an important affector for atherosclerosis in subjects with glucose intolerance. We analyzed the relationship of brachial-ankle pulse wave velocity (baPWV) with fasting and post-challenge plasma glucose levels according to different time points during oral glucose tolerance test (OGTT).

Methods

In 663 subjects with fasting hyperglycemia, 75 g OGTT were performed to confirm the glucose tolerant status, and fasting, post-challenge 30-minute and 120-minute glucose levels were measured. Anthropometric measurements were done, and fasting lipid profiles were measured. baPWV were measured in all subjects and the relationship between fasting, 30- and 120-minute post-challenge glucose levels and baPWV were analyzed.

Results

Among the participants, 62.9% were prediabetes and 31.7% were diabetes. Mean baPWV value was significantly higher in subjects with diabetes compared with prediabetes group. In bivariate correlation analyses, age, blood pressure, total cholesterol, low density lipoprotein cholesterol, 30-minute and 120-minute post-challenge glucose levels showed significant positive correlation with baPWV value. In multiple regression analysis, 30-minute post-challenge glucose level was a weak but significant determinant for mean baPWV value even after adjustment for other confounding variables.

Conclusions

Postprandial hyperglycemia, especially 30-minute glucose levels showed significant correlation with baPWV in subjects with fasting hyperglycemia. These results can imply the deleterious effect of acute hyperglycemic excursion on arterial stiffness in subjects with glucose intolerance.

N-terminal fragment of pro-brain natriuretic peptide (NT-proBNP) for predicting silent myocardial ischaemia in type 2 diabetes mellitus independent of microalbuminuria

BACKGROUND

In the early identification of cardiovascular risk, it is essential to establish a biological marker for cardiac complications that is comparable to albuminuria for nephropathy. We tested the hypothesis that N-terminal pro-brain natriuretic peptide (NT-proBNP) might be a marker for silent myocardial ischaemia in diabetes.

METHODS

In forty consecutively recruited subjects without evident coronary artery disease, serum NT-proBNP was measured together with multi-slice computed tomography. With patients suspected of having significant coronary artery stenosis by multi-slice computed tomography, coronary angiography was performed. Silent myocardial ischaemia was defined as the presence of significant coronary artery stenosis with more than 50% luminal narrowing by angiography.

RESULTS

Thirteen patients (32.5%) had silent myocardial ischaemia. NT-proBNP levels were significantly higher in these patients (181.1 ± 43.8 versus 55.2 ± 9.7 pg/mL, p < 0.005) but HbA(1c), lipid profiles, and creatinine were similar in the two groups. Moreover, log NT-proBNP was identified as an independent predictor of silent myocardial ischaemia (R(2) = 0.502, p < 0.05) after adjustment for HbA(1c), creatinine, albuminuria, hypertension, hyperlipidaemia, or smoking. After stratifying patients by NT-proBNP, the upper tertile compared to the lowest tertile was significantly associated with silent myocardial ischaemia (odds ratio: 26.7, p < 0.05). Receiver operation characteristics analysis with a cut-off value of 52 pg/mL showed 92% sensitivity and 75% specificity for predicting silent myocardial ischaemia (positive predictive value 64.7%, negative predictive value 94.3%).

CONCLUSIONS

The outstandingly high negative predictive value of NT-proBNP enables us to focus on diabetic patients with occult coronary disease, independently of microalbuminuria.

Endothelial function in individuals with coronary artery disease with and without type 2 diabetes mellitus

The goal of this study was to determine if individuals with coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM) had greater endothelial dysfunction (ED) than individuals with only CAD. Flow-mediated dilation (FMD), calculated as percentage increase in brachial artery diameter in response to postischemic blood flow, was measured after an overnight fast in 2 cohorts. The first cohort included 76 participants in the Northern Manhattan Study with CAD; 25 also had T2DM. The second cohort was composed of 27 individuals with both T2DM and CAD who were participants in a study of postprandial lipemia. Combined, we analyzed 103 patients with CAD: 52 with T2DM (T2DM+) and 51 without T2DM (T2DM-). The 52 CAD T2DM+ subjects had a mean FMD of 3.9% +/- 3.2%, whereas the 51 CAD T2DM- subjects had a greater mean FMD of 5.5% +/- 4.0% (P < .03). An investigation of various confounders known to affect FMD identified age and body mass index as the only significant covariates in a multiple regression model. Adjusting for age and body mass index, we found that FMD remained lower in T2DM+ subjects compared with T2DM- subjects (difference, -1.99%; P < .03). In patients with CAD, the concomitant presence of T2DM is independently associated with greater ED, as measured by FMD. This finding may be relevant to the greater early and late morbidity and mortality observed in patients with both CAD and T2DM.

Myocardial perfusion scintigraphy in asymptomatic diabetic patients: a critical review

The increasing prevalence of diabetes mellitus and the associated high cardiovascular risk has made the non-invasive identification of silent coronary heart disease in diabetic individuals an important issue. This strategy could identify higher risk asymptomatic patients with diabetes mellitus in whom coronary revascularization may improve the outcome beyond that achieved by currently recommended medical management. Stress myocardial perfusion imaging has been shown to be effective in detecting coronary heart disease and predicting adverse cardiac events in asymptomatic diabetic patients. However, the clinical utility of myocardial perfusion scintigraphy is debated intensively due to the paucity of prospective and outcome based evidence. The controversy stems from several observational studies, epidemiologic data and cost-effectiveness analyses. Thus, although several authors and professional organizations advocate the use of stress imaging for screening higher risk asymptomatic diabetic patients, others are cautious in recommending any kind of stress testing in that population. This review is based on a broad survey of the literature and discusses the potential role of stress myocardial perfusion scintigraphy in screening asymptomatic diabetic subjects for coronary heart disease in the current era and in relation with other non-invasive screening tools.

Genetic variation in the adiponectin receptor 2 (ADIPOR2) gene is associated with coronary artery disease and increased ADIPOR2 expression in peripheral monocytes

Background

There is debate as to whether the association between C-reactive protein (CRP) and insulin resistance is independent of body fatness, particularly central obesity. Therefore, the association among CRP, insulin resistance and obesity was analyzed in Chinese patients with type 2 diabetes.

Methods

The study included 520 Chinese patients diagnosed with type 2 diabetes with CRP levels not exceeding 10 mg/L. The degree of insulin resistance was determined with the homeostasis model assessment of insulin resistance (HOMA-IR). The CRP levels were categorized into quartiles from the lowest to the highest concentrations (Q1-Q4).

Results

Body mass index (BMI) and waist circumference (WC) were both higher in Q4, Q3 and Q2 than those in Q1. HOMA-IR was higher in Q2, Q3 and Q4 than that in Q1 (Q1 vs Q4, P < 0.001; Q1 vs Q3, P < 0.001; Q1 vs Q2, P = 0.028). Log CRP was significantly correlated with log HOMA-IR (correlation coefficient: 0.230, P < 0.001) and BMI (correlation coefficient: 0.305, P < 0.001) and WC (correlation coefficient: 0.240, P < 0.001) by Spearman correlation analysis. Multiple linear regression analysis adjusting for age, gender and components of metabolic syndrome, log CRP was also independently associated with log HOMA-IR (β coefficient, 0.168; P < 0.001) and WC (β coefficient, 0.131; P = 0.006).

Conclusion

These findings showed that insulin resistance was associated with CRP levels independent of abdominal obesity in Chinese patients with type 2 diabetes, suggesting that abdominal obesity could only partly explain the link between subclinical inflammation and insulin resistance.

Genetic variation in the adiponectin receptor 2 (ADIPOR2) gene is associated with coronary artery disease and increased ADIPOR2 expression in peripheral monocytes

BACKGROUND

Adiponectin is an adipose tissue secreted protein known for its insulin sensitising and anti-atherogenic actions. To this date two adiponectin receptors have been discovered, adiponectin receptor 1 (ADIPOR1) and adiponectin receptor 2 (ADIPOR2). The aim of this study was to investigate the association of ADIPOR2 gene variations with coronary artery disease (CAD).

METHODS

Eight common single nucleotide polymorphisms (SNPs) spanning the entire ADIPOR2 locus were chosen to perform association studies with anthropometric and metabolic parameters in a Greek population. They were classified as either CAD (stenosis >50% in at least one main vessel) or non-CAD individuals in accordance with coronary angiography data.Genotyping was performed using a microsphere-based suspension array and the Allele Specific Primer Extension (ASPE) method. Expression of ADIPOR2 protein and mRNA in circulating CD14+ monocytes were determined using flow cytometry and real time Polymerase Chain Reaction assays respectively.

RESULTS

There was a significant difference in the distribution of genotypes of polymorphism rs767870 of ADIPOR2 between CAD and non-CAD individuals (p = 0.017). Furthermore, heterozygotes of the rs767870 polymorphism had significantly lower Flow Mediated Dilatation (FMD) values, higher values of Intima-Media Thickness (IMT) and increased ADIPOR2 protein levels in peripheral monocytes, compared to homozygotes of the minor allele after adjustment for age, sex, waist to hip ratio and HOMA.

CONCLUSIONS

Our findings suggest that variants of ADIPOR2 could be a determinant for atherosclerosis independent of insulin resistance status, possibly by affecting ADIPOR2 protein levels.

Review: Does hypoglycaemia cause cardiovascular events?

Strict glycaemic control is strongly advocated in people with type 2 diabetes to prevent vascular disease. However, the outcomes of two large clinical trials have indicated the potential dangers of pursuing this policy in those at high risk of cardiovascular disease, with an excess of fatal vascular events being associated with a higher frequency of severe hypoglycaemia. Hypoglycaemia secondary to insulin and sulphonylurea therapy is often associated with serious morbidity; anecdotal evidence has long implicated hypoglycaemia as a potential cause of myocardial ischaemia or a cardiac arrhythmia. Hypoglycaemia provokes sympatho-adrenal activation and counterregulatory hormone secretion, which exert pronounced cardiovascular effects. Although well tolerated in healthy people, the superimposition of these profound physiological effects on a diseased coronary vasculature and a dysfunctional cardiac conductive system may induce serious or even fatal cardiovascular events. These risks should influence therapeutic targets and the approach to diabetes management in people with diabetes with established vascular disease in whom exposure to severe hypoglycaemia could be dangerous.

Intra-renal hemodynamics and carotid intima-media thickness in the metabolic syndrome

AIMS

Metabolic syndrome (MetS) is associated with increased cardiovascular risk. We hypothesize that early vascular changes are already present at the time of diagnosis of MetS. The relationship of different measures of early vascular impairment with body fat distribution and the natural progression of MetS was examined in newly diagnosed subjects non-pharmacologically treated.

METHODS

246 consecutively enrolled subjects were categorized according to the presence of MetS and type 2 diabetes (T2D). Intra-renal Doppler flow was used to ascertain resistive (RI) and pulsatility (PI) indices as markers of vascular resistance. Carotid intima-media thickness (IMT), cutis-rectis (CR) and rectis-aorta (RA) thicknesses were measured by ultrasonography; RA/CR ratio was used as measure of body fat distribution. Pro-inflammatory cytokines, C-reactive protein, oxidative markers insulin and adiponectin blood concentrations were also measured.

RESULTS

Baseline characteristics demonstrated increasing trends in biochemical, inflammatory, and oxidative parameters from MetS-, MetS+, to MetS+/T2D (p<0.001). After adjusting for age, the same increasing trends across the groups were observed in both sexes in IMT (p<0.001), RI (p<0.001) and PI (p<0.001). IMT correlated with RI (r=0.25; p<0.001), PI (r=0.26; p<0.001), and RA/CR ratio (r=0.43; p<0.001).

CONCLUSIONS

Carotid IMT and intra-renal resistances are elevated at an early stage in MetS and are associated with a dysregulated production of fat-derived hormones and cytokines.