Impaired glucose tolerance: A possible contributor to left ventricular hypertrophy and diastolic dysfunction

Detection of early ultrasonographic markers of cardiovascular dysfunction in prediabetes patients: Cardiovascular markers in prediabetes

BACKGROUND

Prediabetes individuals may present incipient signals of cardiovascular injury and evaluate with unfavorable outcome. The aim of this study was to identify early ultrasonographic markers of cardiac dysfunction and arterial stiffness among glucose intolerant patients compared to healthy individuals.

METHODS

Cross-sectional study with the composition of two groups: Prediabetes (PD) who met the criteria for pre-diabetes and Normoglycemic (NG): presented no criteria of pre-diabetes and diabetes mellitus in all applied tests. Clinical evaluation, assessment of cardiac function by transthoracic echocardiogram, carotid intima-media thickness by carotid ultrasonographic and evaluation of arterial stiffness by SphygmoCor®ฏ device were performed.

RESULTS

Eighty adults were included in this study: PD (n=43) and NG (n=37). PD patients were more dyslipidemic and presented early alterations in echocardiographic variables, like: peak mitral velocity E (E (cm/s): NG 84±13 vs PD 77±11, p = 0.03), E/A Tricuspid inflow (NG: 1.5±0.4 vs PD 1.3±0.3, p=0.03), Tricuspid tissue Doppler E' (E'tric (cm/s): NG 15.2±4.4 vs PD 13.4±3.2, p=0.04) and increased arterial stiffness (Pulse Wave Velocity: PWV (m/s): NG 7.2±1.5 vs PD 7.9±1.7, p = 0.03). In the regression analysis, having an impaired oral glucose test was shown to be independently associated with reduced E Mitral, even after adjusting for a set of confounding factors.

CONCLUSION

PD patients showed early signals of an impaired cardiac function and an increased pulse wave velocity when compared with healthy individuals. These results point to treatment optimization strategies, especially when considering preventive measures for cardiovascular outcomes, like diabetic cardiomyopathy.

Prediabetes and the risk of heart failure: A meta-analysis

AIM

To determine the role of prediabetes in the incidence of heart failure (HF).

MATERIALS AND METHODS

We searched electronic databases (PubMed, Embase, Google Scholar and OpenGrey) for studies up to 31 December 2020. Studies were included for meta-analysis if they reported adjusted relative risks (RRs) and 95% confidence intervals (CIs) for the risk of HF for prediabetes compared with normoglycaemia. Prediabetes was defined as impaired fasting glucose (IFG) according to the World Health Organization (WHO) criteria (IFG-WHO), or according to the American Diabetes Association (ADA) definition (IFG-ADA), impaired glucose tolerance (IGT), raised HbA1c according to the ADA criteria (HbA1c-ADA), or according to the International Expert Committee (IEC) recommendation (HbA1c-IEC).

RESULTS

A total of 15 studies comprising 9,827,430 individuals provided data for this analysis. The median follow-up duration of the included studies was 8.0 years. Compared with normoglycaemia, prediabetes was associated with an increased risk for HF: IFG-ADA (RR: 1.09, 95% CI: 1.05-1.13), IFG-WHO (RR: 1.18, 95% CI: 1.07-1.30), IGT (RR 1.58, 95% CI 1.04-2.39), HbA1c-ADA (RR 1.28, 95% CI 1.16-1.41) or HbA1c-IEC (RR 1.40, 95% CI 1.09-1.79), respectively.

CONCLUSIONS

Prediabetes is associated with an increased risk of HF. Future studies are needed to evaluate effective treatments for prediabetes to prevent the development and progression of HF.

Metabolic Risk Factors and Left Ventricular Diastolic Function in Middle-Aged Chinese Living in the Tibetan Plateau

Background

Data regarding the metabolic risk factors clustering on the risk of left ventricular diastolic dysfunction (LVDD) are lacking among people living at high altitude and under hypoxic conditions. In this study, we explored the association between metabolic risk factor clustering and LVDD among the Tibetan population of China.

Methods and Results

We conducted a cross‐sectional survey in a representative sample of 1963 Tibetans in 2014 to 2016. Grading LVDD was based on recommendations for the evaluation of LV diastolic function by echocardiography (2009). The prevalence of LVDD among 1963 participants (mean age: 51.51 years, 41.11% male) was 34.39%. Odds ratios (95% CI) of LVDD for the 1, 2, and 3 to 5 risk factors clustering were 1.45 (0.96–2.17), 2.68 (1.8–3.98), and 2.9 (1.9–4.43), respectively (P for trend <0.001). The association between metabolic risk factors clustering and LVDD was much more pronounced in the middle‐aged group than in the elderly (P for interaction=0.0170). High altitude was one of the major independent risk factors for LVDD; however, habitation altitude had no significant effect on the association between metabolic risk factors and LVDD (P for interaction=0.1022). The multivariable dominance analysis indicated that abdominal obesity, hypertension, and elevated blood glucose were the significant contributors to LVDD.

Conclusions

There was a significant positive association between the metabolic risk factor clustering number and LVDD among a population living at high altitude, especially in middle‐aged adults. However, habitation altitude itself has no significant effect on the association between metabolic risk factors and LVDD.

An observational study of the association among interatrial adiposity by computed tomography measure, insulin resistance, and left atrial electromechanical disturbances in heart failure

Excessive visceral adiposity, hypothesized to be a key mediator in metabolic derangements, has recently been shown to exert toxic effects on cardiac structure and function. Data regarding the mechanistic link between regional adiposity, left atrial (LA) electromechanical remodeling, and heart failure with preserved ejection fraction (HFpEF) have been lacking.Various visceral adiposity measures, including pericardial fat (PCF), thoracic periaortic (TAT) fat, regional inter-atrial fat (IAF), and atrioventricular groove fat (AV Groove Fat), were assessed by multidetector computed tomography in 2 study cohorts (an annual health survey cohort and an outpatient cohort). We related such measures to cardiometabolic profiles in health survey cohort and LA electromechanical indices in our outpatient cohort, with Cox proportional hazards performed to examine the temporal trends of heart failure (HF).In our annual health survey cohort (n = 362), all 4 adiposity measures were positively related to unfavorable anthropometrics and systemic inflammation (high-sensitivity C-reactive protein) (all P < 0.05). In addition, both greater IAF and AV Groove Fat were positively associated with higher fasting glucose, HbA1c levels, and insulin resistance (all P < 0.05). In the outpatient cohort, the HFpEF group demonstrated the greatest adiposity measures, with greater IAF (≥8.2 mm, hazard ratio: 4.11, 95% confidence interval: 1.50-11.32) associated with reduced LA strain (ß-coef: -0.28), higher LA stiffness (ß-coef: 0.23), and longer P wave duration (ß-coef: 0.23) in multivariate models (all P < 0.05), and further related to higher HF hospitalization during follow-up.We therefore propose a possible pathophysiologic link among greater visceral adiposity, systemic inflammation, cardiometabolic risks, and HFpEF. Regional adiposity, especially IAF, was tightly linked to altered LA electromechanical properties and likely plays a key role in HF prognosis.

Impaired fasting glucose and left ventricular diastolic dysfunction in middle-age adults: a retrospective cross-sectional analysis of 2971 subjects

BACKGROUND

Left ventricular (LV) diastolic dysfunction (LVDD) is a well-established and early echocardiographic characteristic of diabetic cardiomyopathy. However, there are limited data on the association between impaired fasting glucose (IFG) and LVDD.

OBJECTIVE

To determine whether IFG is associated with LVDD among middle age adults.

METHODS

Amongst 3781 subjects screened in an annual health survey program and referred for an echocardiogram, 2971 individuals without LV systolic dysfunction or valvular heart disease were selected. Mean age of study population was 59 ± 12 years and 75% were men. The subjects were categorized into three groups: euglycemia (N = 2025), IFG (N = 534) and diabetes mellitus (DM; N = 412). Doppler echocardiography readers were blinded to glycemic state. Subjects with impaired LV relaxation, pseudo-normal or restrictive filling patterns were defined as having LVDD.

RESULTS

LVDD was diagnosed in 574 (19 %) of subjects and it was more prevalent among patients with IFG and DM than in euglycemic individuals (27, 30 and 15%, respectively; p < 0.001). Patients with IFG and DM had lower ratios of early (E) to late (A) trans-mitral flow (0.9 ± 0.3 and 0.9 ± 0.3 vs. 1.1 ± 0.4, respectively, p < 0.001). LV hypertrophy (LVH) was also more prevalent among patients with IFG and DM (11 and 18%, respectively, vs. 9%; p < 0.001). Multivariate binary logistic regression model adjusted to age, gender, obesity, LVH, renal function, total, high and low density lipoprotein cholesterol, triglycerides, ischemic heart disease, hypertension and LV ejection fraction showed that patients with IFG were 43% more likely to have LVDD compared with euglycemic subjects (95% confidence interval 1.12-1.83, p = 0.004).

CONCLUSIONS

IFG is independently associated with a significant increase in the likelihood for the presence of LVDD in middle aged adults.

A meta-analysis of the therapeutic effects of glucagon-like Peptide-1 agonist in heart failure

We conducted a meta-analysis of the existing literature of the therapeutic effects of using GLP-1 agonists to improve the metabolism of the failing heart. Animal studies showed significant improvement in markers of cardiac function, such as left ventricular ejection fraction (LVEF), with regular GLP-1 agonist infusions. In clinical trials, the potential effects of GLP-1 agonists in improving cardiac function were modest: LVEF improved by 4.4% compared to placebo (95% C.I 1.36–7.44, P = 0.005). However, BNP levels were not significantly altered by GLP-1 agonists in heart failure. In two trials, a modest increase in heart rate by up to 7 beats per minute was noted, but meta-analysis demonstrated this was not significant statistically. The small number of studies plus variation in the concentration and length of the regime between the trials would limit our conclusions, even though statistically, heterogeneity chi-squared tests did not reveal any significant heterogeneity in the endpoints tested. Moreover, studies in non-diabetics with heart failure yielded conflicting results. In conclusion, the use of GLP-1 agonists has at best a modest effect on ejection fraction improvement in heart failure, but there was no significant improvement in BNP levels in the meta-analysis.

Prediabetes and blood pressure effects on heart rate variability, QT-interval duration, and left ventricular hypertrophy in overweight-obese adolescents

This ancillary, descriptive correlational study examined the effect of glucose regulation, blood pressure (BP), and their combined effects on cardiac autonomic function in 128 overweight-obese 11-18-year-olds. Measures included body mass index, resting BP, fasting glucose, glucose tolerance, and cardiac autonomic function (heart rate variability, QT, and Cornell voltage). After adjusting for age and gender, multivariate analysis of covariance revealed no differences in cardiac autonomic measures based on glucose regulation (p = .319), BP (p = .286), or the interaction between glucose regulation and BP (p = .132). The additive effect of prediabetes and elevated BP did not impact cardiac autonomic function in overweight-obese youth.

Left ventricle structural remodelling in the prediabetic Goto-Kakizaki rat

This study tested the hypothesis that experimental prediabetes can elicit structural remodelling in the left ventricle (LV). Left ventricles isolated from 8-week-old male Goto-Kakizaki (GK) rats and age-matched male Wistar control rats were used to assess remodelling changes and underlying transforming growth factor β1 (TGFβ1) activity, prohypertrophic Akt-p70S6K1 signalling and gene expression profile of the extracellular matrix (ECM) using histological, immunohistochemical, immunoblotting and quantitative gene expression analyses. Prediabetes in GK rats was confirmed by impaired glucose tolerance and modestly elevated fasting blood glucose. Left ventricle remodelling in the GK rat presented with marked hypertrophy of cardiomyocytes and increased ECM deposition that together translated into increased heart size in the absence of ultrastructural changes or fibre disarray. Molecular derangements underlying this phenotype included recapitulation of the fetal gene phenotype markers B-type natriuretic peptide and α-skeletal muscle actin, activation of the Akt-p70S6K1 pathway and altered gene expression profile of key components (collagen 1α and fibronectin) and modulators of the ECM (matrix metalloproteinases 2 and 9 and connective tissue growth factor). These changes were correlated with parallel findings of increased TGFβ1 transcription and activation in the LV and elevated active TGFβ1 in plasma of GK rats compared with control animals (Student's t test, P < 0.05 versus age-matched Wistar control animals for all parameters). This is the first report to describe LV structural remodelling in experimental prediabetes. The results suggest that ventricular decompensation pathognomonic of advanced diabetic cardiomyopathy may have possible origins in profibrotic and prohypertrophic mechanisms triggered before the onset of type 2 diabetes mellitus.

Myocardial structure and function by echocardiography in relation to glucometabolic status in elderly subjects from 2 population-based cohorts: a cross-sectional study

BACKGROUND

Left ventricular (LV) diastolic dysfunction has been associated with impaired glucometabolic status. However, studies of older subjects are lacking. We examined associations between echocardiographic indices of LV diastolic function and LV mass index (LVMI) and glucometabolic status among middle-aged and elderly subjects free from heart disease, hypothesizing that the associations would be comparative to younger cohorts.

METHODS

We examined the Age Gene/Environment Susceptibility Reykjavik Study (Iceland; n = 607, 76 +/- 6 years) and the Malmö Preventive Project Re-Examination Study (MPP-RES) cohorts (Sweden; n = 1,519, 67 +/- 6 years), evaluating associations with multivariable regression analysis.

RESULTS

In the Age Gene/Environment Susceptibility Reykjavik Study, LVMI was positively correlated with glycosylated hemoglobin (HbA1c) (P = .001). Otherwise, echocardiographic variables were not associated with glucometabolic status. In the MPP-RES, LVMI increased with increasing glucometabolic disturbance among both older (70-80 years) and middle-aged (57-69 years) subjects. Among older subjects, HbA1c was positively correlated with 2 variables reflecting LV diastolic function: late transmitral peak flow velocity (A) (P = .001) and early transmitral peak flow velocity (E)/early diastolic peak tissue velocity (Em) (P = .046). In middle-aged MPP-RES subjects, increasing glucometabolic disturbance was correlated with increasing late diastolic peak tissue velocity (Am) (P = .002) and, after age adjustment, with increasing A (P = .001) and decreasing Em/Am (P = .009). With age adjustment, Am and A were positively correlated with fasting glucose and HbA1c.

CONCLUSIONS

Contrary to our hypothesis, in 2 independent cohorts of older individuals, associations between glucometabolic status and LV diastolic function were generally weak. These contrast with previous reports, as well as with observations among middle-aged subjects in the present study. Changes in LV diastolic function may be more age-related than associated with glucose metabolism in older subjects.

Transmitral E/A ratio decreases in association with abdominal fat accumulation in patients with impaired glucose tolerance or mild diabetes without left ventricular hypertrophy

An abnormal left ventricular (LV) diastolic function is an early sign of diabetic cardiomyopathy, which is characterized by an impaired diastolic and/or systolic function of the left ventricle in the absence of ischemic, valvular, or hypertensive heart disease, and serves as a marker of cardiovascular risk. However, it is unclear whether LV diastolic abnormalities can be detected in patients with impaired glucose tolerance (IGT) or mild diabetes without LV hypertrophy (LVH). We examined echocardiographic data from 92 consecutive Japanese patients aged 45-79 years with or without IGT or mild diabetes in the absence of LVH. Impaired glucose tolerance or mild diabetes was defined as the presence of one or more of the following criteria: fasting plasma glucose >110 mg/dl, hemoglobin A1c >5.6%, homeostasis model assessment ratio >1.73, or the taking of oral antihyperglycemic drugs. Left ventricular hypertrophy was defined as an LV mass index (LVMI) >116 g/m(2) in men and >104 g/m(2) in women. Patients with ischemic, valvular, or hypertensive heart disease were excluded. The age, blood pressure, heart rate, and LVMI were similar between patients with (IGT/DM group, n = 43) and without IGT or mild diabetes (non-IGT/DM group, n = 49), whereas the body mass index and waist circumference (WC) were greater in the IGT/DM compared to the non-IGT/DM group (P < 0.05 and P < 0.001, respectively). The transmitral E/A ratio was lower and the deceleration time longer in the IGT/DM than in the non-IGT/DM group (both P < 0.05). Stepwise regression analysis revealed that age and WC were independent determinants of the E/A ratio. In conclusion, diastolic abnormalities without LVH can be detected in Japanese patients with IGT or mild diabetes. The E/A ratio decreases in association with abdominal fat accumulation.

A, Ribeiro JM. Is there a link between glucose levels and heart failure? An update

It has been well documented that there is an increased prevalence of standard cardiovascular (CV) risk factors in association with diabetes and with diabetes-related abnormalities. Hyperglycemia, in particular, also plays an important role. Heart failure (HF) has become a frequent manifestation of cardiovascular disease (CVD) among individuals with diabetes mellitus. Epidemiological studies suggest that the effect of hyperglycemia on HF risk is independent of other known risk factors. Analysis of datasets from populations including individuals with dysglycemia suggests the pathogenic role of hyperglycemia on left ventricular function and on the natural history of HF. Despite substantial epidemiological evidence of the relationship between diabetes and HF, data from available interventional trials assessing the effect of a glucose-lowering strategy on CV outcomes are limited. To provide some insight into these issues, we describe in this review the recent important data to understand the natural course of CV disease in diabetic individuals and the role of hyperglycemia at different times in the progression of HF.