Fasting plasma glucose is an independent determinant of left ventricular diastolic dysfunction in nondiabetic patients with treated essential hypertension

Triglyceride glucose index reflects the unfavorable changes of left ventricular diastolic functions and structure in uncomplicated newly diagnosed hypertensive patients

INTRODUCTION

Left ventricular (LV) diastolic dysfunction and structural abnormalities are common cardiac changes in hypertension (HTN), and several factors other than high blood pressure (BP) may play a role in these changes. The aim of this study was to reveal the relationship between triglyceride glucose (TyG) index, a novel parameter for insulin resistance (IR), with LV diastolic function and structure in hypertensive patients.

MATERIAL AND METHOD

A total of 119 newly diagnosed, untrated hypertensive patients free of diabetes and/or cardiovascular complications were included in this study. IR was estimated with the TyG index calculated from ln [fasting TG (mg/dL) × fasting blood glucose (mg/dL)/2]. Two-dimensional and Doppler echocardiographic examinations were performed to assess LV diastolic functions and structure.

RESULTS

Based on median TyG index, 51 patients was assigned as group I (<8.7) and 68 patients as group II (>8.7). In patients with high TyG index, left atrial volume index (LAVi) (p < .001) LV mass index (LVMI) (p = .016), E/e' ratio (p < .001) increased, and e' velocity (p < .001) and E/A ratio (p = .028) decreased. There was a statistically significant correlation between TyG index and these parameters (all p > .05). Stepwise multiple regression analysis demonstrated that the relationship of TyG index with LV diastolic function and structure was independent of potential confounders (all p < .001).

CONCLUSION

This study suggest that a high TyG index is related to LV diastolic functional impairment and structure abnormality in newly diagnosed hypertensive patients in the absence of diabetes or CVD.

Glycated hemoglobin as a marker of subclinical atherosclerosis and cardiac remodeling among non-diabetic adults from the general population

BACKGROUND

Elevated glycated hemoglobin (HbA1c) is associated with increased risk of cardiovascular disease (CVD) and mortality but little is known about potential mechanisms underlying the reported associations.

METHODS

We used data from 1798 non-diabetic participants from the population-based cohort Study of Health in Pomerania (SHIP) to investigate cross-sectional and longitudinal associations of HbA1c with subclinical atherosclerosis (common carotid artery intima-media thickness [CCA-IMT]), cardiac structure (left ventricular mass [LVM]), and cardiac function (fractional shortening).

RESULTS

Cross-sectional analyses revealed a positive association between HbA1c and mean CCA-IMT with a 0.02 mm (95% confidence interval: 0.01-0.04) increase in CCA-IMT per 1% increase in HbA1c, and a similar positive trend across HbA1c quartiles (overall p-value <0.01). We also observed a graded association between HbA1c and high CCA-IMT (>75th percentile) with an odds ratio of 1.42 (95% CI: 1.11-1.81) per 1% increase in HbA1c. Longitudinal analyses showed no consistent associations of baseline HbA1c with mean follow-up CCA-IMT. There were no consistent associations of HbA1c with cardiac remodeling in cross-sectional and longitudinal analyses, respectively.

CONCLUSIONS

The association between HbA1c and CCA-IMT in non-diabetic adults may be a crucial link between high-normal HbA1c levels and an increased risk of CVD and mortality.

Aortic elastic properties in nonalcoholic fatty liver disease

BACKGROUND

Recent studies have shown that patients with nonalcoholic fatty liver disease (NAFLD) have an increased risk of developing cardiovascular disease. Aortic stiffness, an early marker of arteriosclerosis, is associated with cardiovascular mortality. In this study, the aortic elastic properties of nondiabetic, normotensive NAFLD patients were evaluated.

METHODS

Thirty-five patients with NAFLD and 30 age-matched and sex-matched healthy controls were enrolled. Aortic distensibility, aortic strain, aortic stiffness index (ASI), left ventricular mass index (LVMI), homeostasis model assessment of insulin resistance (HOMA-IR) and fasting lipid parameters were assessed in both the groups.

RESULTS

ASI was higher in NAFLD patients (7.1+/-2.0) than in the control group (3.8+/-1.0) (P<0.01). Aortic distensibility and aortic strain were also significantly decreased in NAFLD patients as compared with the control group (2.9+/-0.7 cm/dyn vs. 6.3+/-2.4 cm/dyn, P<0.0001 and 7.1+/-1.7 vs. 14.5+/-4.0, P<0.0001, respectively). Although ASI was significantly correlated with age, HOMA-IR, waist circumference, body mass index and LVMI, a stepwise multiple linear regression analysis showed that HOMA-IR and LVMI were the only variables associated with ASI index [(standardized beta coefficient= 0.41, P=0.004, overall R=0.17) and (standardized beta coefficient=0.31, P=0.02, overall R=0.10), respectively].

CONCLUSION

Our data suggest that aortic elasticity is significantly impaired and is also associated with insulin resistance and LVMI in NAFLD patients, which may contribute to the relationship between NAFLD and the increased risk of cardiovascular disease among these patients.

Metabolic syndrome: treatment of hypertensive patients

Metabolic syndrome (MetSyndr), a constellation of abnormalities [obesity, glucose intolerance, insulin resistance (IR), dyslipidemia (low HDL-cholesterol, high LDL-cholesterol and triglycerides (TG)], and elevated blood pressure (BP)], increases the risk of cardiovascular (CV) disease and premature death. From 10% to 30% of the adult population in industrialized countries has MetSyndr, which effectively predicts the development of type 2 diabetes mellitus (T2D) and CV disease. Because of the complex etiology of MetSyndr, a multi-targeted, integrated therapeutic approach is required to simultaneously treat high BP, obesity, lipid disorders and T2D (if present), to fully protect CV, cerebrovascular and renal systems. If lifestyle modification (weight control, diet, exercise, smoking cessation, moderation of alcohol intake) is ineffective, pharmaco-theraphy should be added to treat simultaneously the lipid- and non-lipid CV risk factors. Patients with HTN and MetSyndr should be started on angiotensin-converting enzyme (ACE) inhibitors, unless contraindicated. The ACE inhibitors and angiotensin receptor blockers (ARBs) reduce the odds of developing new onset T2D and also decrease albuminuria. The ACE inhibitors provide cardioprotective and renoprotective benefits beyond their effect on BP; they also improve IR. The ARBs are renoprotective in addition to being cardioprotective. Long-acting calcium channel blockers are also recommended in hypertensive patients with MetSyndr; these drugs also improve IR. Thiazides (at low doses) and selected ss-blockers can be given to patients with HTN and MetSyndr. Celiprolol in combination with diuretics has a favorable effect on glucose tolerance and IR in patients with HTN and MetSyndr, and spironolactone added to ACE inhibitor or ARB therapy provides additional reno- and CV protective benefits in patients with diabetic nephropathy. Carvedilol, a ss-blocker with vasodilating properties, added to ACE inhibitor or ARB therapy, is effective in preventing worsening of microalbuminuria in patients with HTN and MetSyndr; it also improves IR and glycemic control. Most patients eventually require two or more antihypertensive drugs to reach BP goal. It is recommended that therapy in patients whose BP is more than 20/10 mm Hg above target at diagnosis be initiated with a combination of antihypertensive drugs, administered either as individual drugs or as fixed-dose formulations. Treatment with fixed-dose combinations, such as irbesartan + hydrochlorothiazide provides good BP control in more than two-thirds of hypertensive patients with MetSyndr. Lipid and BP targets are reached in a high percent of patients with HTN and CV disease treated with a combination of amlodipine + atorvastatin. In conclusion, hypertensive patients with the MetSyndr be treated aggressively for each component of the syndrome to provide CV, cerebrovascular and renal protection.

Left Ventricular Geometry and Renal Function in Hypertensive Patients With Diastolic Heart Failure

BACKGROUND

The objective is to define the relationship between cardiac geometry and renal function in hypertensive subjects with and without diastolic heart failure (DHF).

METHODS

This is a prospective observational study in a tertiary-care teaching institute in a 15-month period of consecutive hospitalized hypertensive patients. Patients on dialysis therapy or with atrial fibrillation, systolic heart failure, gross proteinuria, and glomerular diseases were excluded. Two-dimensional echocardiography was performed and stable glomerular filtration rate (GFR) was calculated by using the Modification of Diet in Renal Disease formula. Patients were classified into stage 1 to 5 chronic kidney disease (CKD).

RESULTS

Five hundred forty hypertensive patients were separated into 2 groups: 286 patients with DHF and 254 patients without DHF. Mean age was 69.1 +/- 13.7 (SD) years in general. In patients with DHF, from stages 1 to 5 CKD, there was a significant graded increase in left ventricular mass index (from 117.3 to 162.4 g/m(2)) and relative wall thickness (from 0.42 to 0.52) and a significant graded decrease in aortic cusp separation (from 1.85 to 1.55 cm). Among echocardiographic variables, left ventricular mass index and relative wall thickness were associated inversely and aortic cusp separation was associated directly with GFR. In the absence of DHF, only left ventricular mass index was associated inversely with GFR, suggesting a prominent role of aortic cusp separation and relative wall thickness in the variability in GFR in patients with DHF through a hemodynamic disturbance.

CONCLUSION

Hemodynamic alterations have a prominent role in the variability of GFR in patients with CKD with DHF. Adverse cardiac geometry is linked to the severity of CKD in hypertensive patients, raising the possibility of preserving both cardiac and renal function by means of hypertension control.

Potential impact of carbohydrate and fat intake on pathological left ventricular hypertrophy

Currently, a high carbohydrate/low fat diet is recommended for patients with hypertension; however, the potentially important role that the composition of dietary fat and carbohydrate plays in hypertension and the development of pathological left ventricular hypertrophy (LVH) has not been well characterized. Recent studies demonstrate that LVH can also be triggered by activation of insulin signaling pathways, altered adipokine levels, or the activity of peroxisome proliferator-activated receptors (PPARs), suggesting that metabolic alterations play a role in the pathophysiology of LVH. Hypertensive patients with high plasma insulin or metabolic syndrome have a greater occurrence of LVH, which could be due to insulin activation of the serine-threonine kinase Akt and its downstream targets in the heart, resulting in cellular hypertrophy. PPARs also activate cardiac gene expression and growth and are stimulated by fatty acids and consumption of a high fat diet. Dietary intake of fats and carbohydrate and the resultant effects of plasma insulin, adipokine, and lipid concentrations may affect cardiomyocyte size and function, particularly in the setting of chronic hypertension. This review discusses potential mechanisms by which dietary carbohydrates and fats ca affect cardiac growth, metabolism, and function, mainly in the context of pressure overload-induced LVH.

Cardiac abnormalities as a new manifestation of nonalcoholic fatty liver disease: echocardiographic and tissue Doppler imaging assessment

Nonalcoholic fatty liver disease (NAFLD) is linked to the metabolic syndrome. The aim of the present study is to determine the effect of the metabolic syndrome on left ventricular (LV) geometry and function using as a model patients with NAFLD. Thirty-eight patients with NAFLD, less than 55 years of age and with a normal exercise test, were compared with an age and sex-matched control group. Patients with diabetes mellitus, hypertension, and body mass index>40 were excluded. A complete echocardiographic study including tissue Doppler imaging (TDI) was performed. The following parameters were assessed by echo Doppler: peak velocities of early (E) and late (A) diastolic filling, E/A ratio, flow propagation velocity (Vp). Using TDI early diastolic velocity (E'), and systolic velocity (S') of mitral annulus were obtained. The patients with NAFLD had a significantly higher body mass index (31.4+/-5 vs. 26.4+/-4 kg/m, P=0.01), higher glucose (100.6+/-13 vs. 83.0+/-10 mg/dL, P=0.01), and triglyceride levels (126.5+/-44 vs. 206.5+/-67 mg/dL, P<0.001). Increased thickness of the intraventricular septum, posterior wall (11.03+/-2.2 vs. 8.9+/-2.9 mm, P=0.001; 8.5+/-1.7 vs. 9.7+/-2.3 mm, P=0.04), and larger LV mass and LV mass/height (160.7+/-58.7 vs.115.3+/-35.4 g, P=0.001 and 92.6+/-29.5 vs. 69.2+/-19.8 g/m, P=0.001, respectively) were found in NAFLD group. LV systolic function was similar in both groups. Patients with NAFLD had a lower E (73.6+/-11.0 vs. 86.4+/-20.0 cm/s, P<0.006) and E/A ratio (1.0+/-0.3 vs. 1.76+/-0.8 P<0.0001). Moreover, the Vp and the E' on TDI were significantly lower compared with the control group (49.0+/-9.7 vs. 74.7+/-18.4 cm/s, P<0.0001 and 10.3+/-2.0 vs. 13.8+/-1.7 cm/s, P<0.0001, respectively). On multivariate analysis the E' on TDI was the only independent parameter associated with NAFLD. In conclusion, patients with NAFLD in the absence of morbid obesity, hypertension, and diabetes have mildly altered LV geometry and early features of left ventricular diastolic dysfunction. Early diastolic velocity on TDI was found to be the only index that could identify the patients with NAFLD and metabolic syndrome.

Is glycated haemoglobin a sensitive index to identify left ventricular dysfunction two months after acute myocardial infarction in normotensive subjects?

BACKGROUND

Glycated haemoglobin concentration (HbA1c) is a marker of glucose metabolism. Glucose intolerance is associated with a high incidence of left ventricular (LV) dysfunction after acute myocardial infarction (AMI). This study was carried out in order to relate HbA1c to LV function two months following AMI in 171 normotensive patients who were not previously known to have had diabetes mellitus.

METHODS

Oral glucose tolerance test (GTT) and HbA1c. Echo and Doppler-cardiography were used to measure the E/A (peak velocity of the early filling/atrial contraction waves) at rest and at peak isometric exercise (IME), deceleration time (DT) of E wave, LV ejection fraction (LVEF), LV mass index and diastolic LV function.

RESULTS

GTT was diabetic in 20, impaired in 35 and normal in 116 subjects. HbA1c was >6.0% (cut off level for high risk subjects) in 76 patients (67%) with impaired relaxation (E/A<1) during IME and in 30 patients (27%) with restrictive LV filling (identified by E/A=1-2, DT<140 ms). The sensitivity and specificity of HbA1c to predict underlying impaired LV relaxation were 68% and 37%, respectively, and to predict restrictive LV filling were 27% and 98%, respectively. Whereas in univariate analysis, DT.3 was linearly related to HbA1c only (p=0.0002), multiple regression analysis showed that HbA1c was related to LVEF, DT and E/A but not to LVH, LVMI, smoking habit, age, gender and creatinine kinase level during admission for AMI.

CONCLUSION

At 2 months after admission for AMI, HbA1c is related to systolic and diastolic LV function but not to LVMI or LVH. HbA1c is a sensitive predictor of impaired relaxation but highly specific to rule out underlying non-restrictive LV filling.

Immediate but not long-term intranasal administration of insulin raises blood pressure in human beings

Intranasal administration of insulin has been shown to influence neuroendocrine functions via an effect on central nervous mechanisms. Because insulin, in particular when infused into cerebral arteries, induces blood pressure (BP) elevation by an unknown mechanism, we investigated whether insulin exerts similar effects on BP after intranasal administration. To evaluate the immediate effects of insulin on BP, 20 IU of human insulin was intranasally administered every 10 minutes over a 2-hour period. Blood pressure, heart rate, and muscular sympathetic nervous activity (MSNA) were continuously monitored. For evaluating the effects of subchronic administration of insulin, changes during and after 8 weeks of treatment with 160 IU insulin/d on BP were monitored. Compared with placebo, the immediate nasal administration of insulin raised diastolic BP (12.21% +/- 5.10%; P < .05), mean arterial BP (10.81% +/- 4.32%; P < .04), and systolic BP (9.53% +/- 4.66%; P < .08), whereas MSNA and heart rate were unaffected. In contrast, prolonged intranasal insulin administration did not affect BP (P > .62 for all comparisons). The immediate increase in BP in the face of an unsuppressed MSNA after insulin suggests that intranasal insulin transiently changes the baroreflex set point. Thus, data suggest that intranasal insulin administration affects BP regulatory centers in the brain. However, the effect is not observed with prolonged administration of the hormone, suggesting the emergence of counterregulatory processes.

Left ventricular hypertrophy and preclinical impaired glucose tolerance and diabetes mellitus contribute to abnormal left ventricular diastolic function in hypertensive patients

BACKGROUND

Impaired left ventricular diastolic function is not uncommon in patients with either diabetes mellitus or hypertension. This study was carried out to assess the contribution of left ventricular hypertrophy, high blood pressure, preclinical impaired glucose tolerance and diabetes mellitus to left ventricular diastolic function in patients attending a hypertension clinic.

METHODS

Echocardiography, 24-h ambulatory blood pressure monitoring and oral glucose tolerance tests were carried out in 152 consecutive hypertensive patients who had no evidence of ischaemic heart disease and were not known to be diabetic. From echocardiography, E/A (peak velocity of early/atrial filling waves of the transmitral flow) at rest and at peak standardized isometric exercise using handgrip, left ventricular mass index and deceleration time of the E wave were derived.

RESULTS

Patients with impaired glucose tolerance and diabetes mellitus had lower E/A than the euglycaemic subjects both at rest (P=0.0073) and during isometric exercise (P<0.0001). E/A significantly reduced during isometric exercise in patients with impaired glucose tolerance and diabetes but not in euglycaemic patients. Deceleration time was shortened with a worsening degree of glucose intolerance in all the patients (P=0.0005), in those with left ventricular hypertrophy (P=0.0006) and in those without left ventricular hypertrophy (P=0.033). When adjusted for age, gender, race, body mass index, smoking history, ambulatory blood pressure findings, cholesterol and triglyceride levels and antihypertensive medications taken, E/A at isometric exercise was related to results of glucose tolerance tests and was inversely proportional to left ventricular mass index (P<0.0001). No significant differences were found whether patients were taking antihypertensive medications or not.

CONCLUSION

In hypertensive patients, left ventricular diastolic function is determined by left ventricular mass index and the status of preclinical glucose intolerance, independent of age, gender, race, body mass index, blood pressure level, nocturnal drop in blood pressure or lipid level. These findings were not prejudiced by antihypertensive medications.

Left ventricular diastolic dysfunction in patients with chronic renal failure: impact of diabetes mellitus

AIMS

Left ventricular (LV) hypertrophy and LV diastolic dysfunction are cardiac changes commonly observed in patients with chronic renal failure (CRF) as well as hypertension. Although the impairment of LV diastolic function in patients with diabetes mellitus has been shown, little is known about the specific effect of diabetes on LV diastolic function in patients with CRF. The present study was designed to investigate the impact of diabetic nephropathy on LV diastolic dysfunction, independent of LV hypertrophy, in CRF patients.

METHODS

In 67 patients with non-dialysis CRF as a result of chronic glomerulonephritis (n = 33) or diabetic nephropathy (n = 34), and 134 hypertensive patients with normal renal function, two-dimensional and Doppler echocardiographic examinations were performed, and LV dimension, mass, systolic function, and diastolic function were evaluated.

RESULTS

LV mass was increased and LV diastolic dysfunction was advanced in subjects with CRF compared with hypertensive controls. In the comparison of echocardiographic parameters between the two groups of CRF patients, i.e. chronic glomerulonephritis and diabetic nephropathy groups, all indices of LV diastolic function were more deteriorated in the diabetic nephropathy group than in the chronic glomerulonephritis group, although LV structure including hypertrophy and systolic function did not differ between the groups. In a multiple regression analysis, the presence of diabetes (i.e. diabetic nephropathy group) was a significant predictor of LV diastolic dysfunction in CRF subjects, independent of other influencing factors such as age, blood pressure, renal function, anaemia and LV hypertrophy.

CONCLUSION

The present findings suggest that LV diastolic dysfunction, independent of LV hypertrophy, is specifically and markedly progressed in patients with CRF as a result of diabetic nephropathy.

Association between Left Ventricular Diastolic Dysfunction and Renal Hemodynamic Change in Patients with Treated Essential Hypertension

The heart and kidneys are important target organs in hypertension. Early signs of hypertensive target organ damage can be detected by evaluating left ventricular (LV) diastolic function and intrarenal hemodynamics using Doppler ultrasonography. However, it has not been sufficiently clarified whether cardiac damage and renal impairment progress in parallel, especially from the early stage. In the present study, Doppler echocardiography and renal Doppler ultrasonography were performed in 99 patients with treated essential hypertension, and LV diastolic filling parameters, ie., the velocity ratio of atrial filling to early diastolic filling (A/E), and the deceleration time of the E wave (DcT) and renal Doppler parameters, i.e., the diastolic to systolic ratio (D/S) and resistance index (RI), were determined. D/S was negatively correlated and RI was positively correlated with A/E and DcT. These cardiac and renal Doppler parameters were also associated with age, diastolic blood pressure, creatinine clearance, and/or glucose levels. By multiple regression analysis, D/S was found to have a significant association with DcT, independent of other clinical parameters, including age. In subgroup analysis in which patients were divided by their glucose tolerance, a significant correlation between renal Doppler parameters and LV diastolic function was observed in subjects with normal glucose tolerance, but this correlation disappeared in those with impaired glucose tolerance and diabetes mellitus. The present findings show that there is a significant relation between LV diastolic function and renal Doppler parameters in treated hypertensive patients, and suggest that cardiac damage progresses in parallel with renal involvement in these patients from the early stage.