Role of glucose intolerance in cardiac diastolic function in 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.

Possible value of galectin-3 on follow-up of cardiac remodeling during glucocorticoid treatment

Glucocorticoids are among the most prescribed drugs globally due to their potent anti-inflammatory and immunosuppressive properties. Although they have positive effects on the treatment of various disease states; long-term administration is associated with high blood pressure, insulin resistance, and susceptibility to type 2 diabetes. The heart attempts to cope with increased blood pressure and a decrease in glucose utilization by developing pathological cardiac remodeling. However, in this process, cardiac fibrosis formation and deterioration in heart structure and functions occur. Galectin-3, a member of the β-galactoside binding lectins, is consistently associated with inflammation and fibrosis in the pathogenesis of various disease states including insulin resistance and heart failure. Galectin-3 expression is markedly increased in activated macrophages and a subset of activated fibroblasts and vascular cells. Also, failing and remodeling myocardium show increased Gal-3 expression and elevated Gal-3 levels are related to heart failure severity and prognosis. Furthermore, Gal-3-related pathways are recently suggested as therapeutic targets both pharmacologically and genetically to increase insulin sensitivity in vivo. The objective of this review is to provide a summary of our current understanding of the role of glucocorticoid-associated insulin resistance, which is important for some cardiac events, and the potential role of galectin in this pathophysiological process.

Left ventricular mass, geometry and function in diabetic patients affected by coronary artery disease

INTRODUCTION

Coronary artery disease (CAD) is quite common among diabetic patients, our study goal is to detect the prevalence of left ventricular (LV) adverse changes in geometry, mass and diastolic function on diabetic, but not hypertensive patients, with coronary artery disease(CAD) and LV ejection fraction(LVEF)>45%, actually unknown, because of current guidelines that do not include echocardiographic assessment for follow up of diabetic patients.

PATIENTS AND METHODS

665 consecutive diabetic patients (443 females, mean age 66±9years), performed a complete echocardiographic assessment according to current ASE echo-guidelines: diastolic dysfunction (DD), eccentric hypertrophy (EH), concentric hypertrophy (CH) and concentric remodeling (CR) of LV were reported. CAD was assessed only by reports of bypass surgery, angioplasty or patients hospitalized for acute myocardial infarction.

RESULTS

218 patients (32.8%) presented LV changes: LVDD 49 (7.4%), LVEH 68 (10.2%), LVDD and EH 46 (6.9%), LVDD and CH 36 (5.4%), LVDD and CR 19 (2.9%). 447 (67.2%) had no LV changes. 81 (12.1%) patients with CAD, presented: LVDD 17 (21%), LVEH 32 (39.5%), LVDD and EH 9 (11.1%), LVDD and CH 7 (8.6%), LVDD and CR 8 (9.9%), 8 (9.9%) had no LV adverse changes. There were among CAD patients, a significantly higher prevalence of LVDD (p<0.02), LV eccentric hypertrophy (EH) (p<0.05), DD and LVEH (p<0.04), DD and LV concentric hypertrophy(CH) (p<0.03) and DD and LV concentric remodeling (p<0.02), when compared with those patients without CAD.

CONCLUSION

CAD is related to all different patterns of LV adverse changes in mass, geometry and diastolic function, with a significantly higher prevalence in our population of diabetic patients with normal systolic function. These changes however remain unrecognized until they undergo to a conventional echocardiographic assessment. We support this tool need to be included into future guidelines concerning follow-up of diabetic patients.

Mineralocorticoid receptor blockade improves diastolic function independent of blood pressure reduction in a transgenic model of RAAS overexpression

There is emerging evidence that aldosterone can promote diastolic dysfunction and cardiac fibrosis independent of blood pressure effects, perhaps through increased oxidative stress and inflammation. Accordingly, this investigation was designed to ascertain if mineralocorticoid receptor blockade improves diastolic dysfunction independently of changes in blood pressure through actions on myocardial oxidative stress and fibrosis. We used young transgenic (mRen2)27 [TG(mRen2)27] rats with increases in both tissue ANG II and circulating aldosterone, which manifests age-related increases in hypertension and cardiac dysfunction. Male TG(mRen2)27 and age-matched Sprague-Dawley rats were treated with either a low dose (∼1 mg·kg(-1)·day(-1)) or a vasodilatory, conventional dose (∼30 mg·kg(-1)·day(-1)) of spironolactone or placebo for 3 wk. TG(mRen2)27 rats displayed increases in systolic blood pressure and plasma aldosterone levels as well as impairments in left ventricular diastolic relaxation without changes in systolic function on cine MRI. TG(mRen2)27 hearts also displayed hypertrophy (left ventricular weight, cardiomyoctye hypertrophy, and septal wall thickness) as well as fibrosis (interstitial and perivascular). There were increases in oxidative stress in TG(mRen2)27 hearts, as evidenced by increases in NADPH oxidase activity and subunits as well as ROS formation. Low-dose spironolactone had no effect on systolic blood pressure but improved diastolic dysfunction comparable to a conventional dose. Both doses of spironolactone caused comparable reductions in ROS/3-nitrotryosine immunostaining and perivascular and interstitial fibrosis. These data support the notion mineralocorticoid receptor blockade improves diastolic dysfunction through improvements in oxidative stress and fibrosis independent of changes in systolic blood pressure.

Non-alcoholic fatty liver disease is associated with left ventricular diastolic dysfunction in essential hypertension

BACKGROUND AND AIM

Insulin resistance is recognized as the pathophysiological hallmark of non-alcoholic fatty liver disease (NAFLD). A relation between insulin sensitivity and left ventricular morphology and function has been reported in essential hypertension, where a high prevalence of NAFLD has been recently found. We investigated the inter-relationship between left ventricular morphology/function, metabolic parameters and NAFLD in 86 never-treated essential hypertensive patients subdivided in two subgroups according to the presence (n = 48) or absence (n = 38) of NAFLD at ultrasonography.

METHODS AND RESULTS

The two groups were similar as to sex, age and blood pressure levels. No patient had diabetes mellitus, obesity, hyperlipidemia, or other risk factors for liver disease. Body mass index, waist circumference, triglycerides, glucose, insulin, homeostasis model of assessment index for insulin resistance (HOMA-IR), aspartate aminotransferase and alanine aminotransferase were higher and adiponectin levels were lower in patients with NAFLD than in patients without NAFLD, and were associated with NAFLD at univariate analysis. Patients with NAFLD had similar prevalence of left ventricular hypertrophy compared to patients without NAFLD, but a higher prevalence of diastolic dysfunction (62.5 vs 21.1%, P < 0.001), as defined by E/A ratio <1 and E-wave deceleration time >220 ms. Diastolic dysfunction (P = 0.040) and HOMA-IR (P = 0.012) remained independently associated with NAFLD at backward multivariate analysis.

CONCLUSIONS

Non-alcoholic fatty liver disease was associated with insulin resistance and abnormalities of left ventricular diastolic function in a cohort of patients with essential hypertension, suggesting a concomitant increase of metabolic and cardiac risk in this condition.

Left ventricular dysfunction in Klinefelter syndrome is associated to insulin resistance, abdominal adiposity and hypogonadism

OBJECTIVE

Epidemiological data suggest there is an increased risk of dying from heart disease among patients with Klinefelter syndrome (KS). Due to high prevalence of hypogonadism and metabolic syndrome, we speculated that patients with KS may have subclinical changes in the left ventricular function. Therefore, the aim was to assess left ventricular long axis function by tissue Doppler echocardiography in patients with KS and relate these findings to the metabolic status and testosterone levels.

DESIGN

Cross-sectional study. Out-patient clinic.

PATIENTS

We investigated 25 unselected patients with KS, recruited from endocrine and fertility clinics. Twenty-five age-matched males served as controls.

MEASUREMENTS

Left ventricular systolic long axis function (velocities and strain rate) assessed by tissue Doppler echocardiography related to free testosterone, fasting values of plasma glucose, insulin, homeostasis model assessment (HOMA)-index, cholesterol and triglycerides in addition to dual energy X-ray absorptiometry (DEXA) scan derived assessment of truncal body fat.

RESULTS

The long axis function was significantly reduced in patients with KS (peak systolic velocities 4.4 +/- 1.3 vs. 5.3 +/- 1.0 cm/s, P < 0.01 and strain rate -1.3 +/- 0.3 vs.-1.6 +/- 0.3 s(-1), P < 0.01). However, the ventricular dysfunction was mainly attributed KS patients with metabolic syndrome. The peak systolic velocities were significantly correlated to truncal body fat (r = -0.72, P < 0.01) and free testosterone (r = 0.63, P < 0.01), but uncorrelated to plasma glucose, insulin and HOMA-index.

CONCLUSION

Systolic long axis function is decreased in patients with KS and metabolic syndrome. The decrease in myocardial systolic function was significantly related to truncal body fat and hypogonadism, but not correlated to insulin sensitivity.

Relationship between insulin resistance and left ventricular diastolic dysfunction in patients with impaired glucose tolerance and type 2 diabetes

AIM

The aim of this study was to explore the relationship between insulin resistance (IR) and the left ventricular diastolic function in patients with type 2 diabetes and subjects with impaired glucose tolerance (IGT).

METHODS

The study included 119 subjects who underwent oral glucose tolerance test (OGTT). IR was assessed using Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and Quantitative Insulin Sensitivity Check Index (QUICKI). Left ventricular diastolic function was assessed using trans-thoracic Doppler echocardiography.

RESULTS

Based on the OGTT results, 29 subjects had normal glucose tolerance (NGT), 20 subjects had impaired glucose tolerance (IGT), and 70 patients had type 2 diabetes. There were significant differences among the patients in groups with NGT, IGT and diabetes regarding HOMA-IR (4.20 +/- 1.20 vs. 6.45 +/- 3.83 vs. 8.70 +/- 6.26; P < 0.001) and QUICKI (0.54 +/- 0.11 vs. 0.49 +/- 0.08 vs. 0.47 +/- 0.08; P < 0.001). In subjects with NGT, IGT and patients with diabetes, the pulsed Doppler transmitral variables were: E-wave (0.72 +/- 0.16 cm/s vs. 0.62 +/- 0.13 cm/s vs. 0.58 +/- 0.17 cm/s; P < 0.001), A-wave (0.61 +/- 0.13 cm/s vs. 0.62 +/- 0.11 cm/s vs. 0.71+/- 0.14 cm/s; P = 0.006) and E/A ratio (1.22 +/- 0.33 vs. 1.02 +/- 0.24 vs. 0.85 +/- 0.26; p < 0.001). The proportion of subjects with an E/A ratio <1 was 27.6% in the group with NGT, 55% in the group with IGT and 75.7% in the group with diabetes (P < 0.001). The E/A ratio correlated with HOMA-IR (r = -0.30, p = 0.001) and QUICKI (r = 0.37, p < 0.0001). Multiple linear regression model showed that IR (assessed by QUICKI) was an independent correlate of diastolic dysfunction (P = 0.034).

CONCLUSIONS

In subjects with impaired glucose tolerance and patients with type 2 diabetes, insulin resistance is associated with impaired diastolic function of the left ventricle.

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.

Insulin resistance and inflammatory activation in older patients with systolic and diastolic heart failure

OBJECTIVE

To evaluate insulin resistance and systemic inflammation in older patients with systolic (SHF) or diastolic heart failure (DHF).

PATIENTS

52 non-diabetic patients (> 70 and < 90 years old) with chronic heart failure (CHF) and hospitalised within the previous six months for heart failure were studied, together with a control group of older healthy volunteers (n = 26). On the basis of Doppler echocardiographic criteria patients were classed as having SHF (n = 27) or DHF (n = 25).

MAIN OUTCOME MEASURES

Fasting glucose, insulin, C reactive protein, interleukin 6, and tumour necrosis factor alpha soluble receptor II (TNF-alphaSRII) concentrations were determined. Insulin resistance was estimated by the homeostasis model assessment (HOMA).

RESULTS

HOMA index (median, interquartile range) was higher in patients with DHF (1.77, 1.06-2.26) than in patients with SHF (0.97, 0.81-1.85) or healthy volunteers (1.04, 0.76-1.44; p = 0.01). After adjustment for body mass index, age, and use of angiotensin converting enzyme inhibitors, both groups of patients with CHF were more insulin resistant than were healthy volunteers (p = 0.02). C reactive protein, interleukin 6, and TNF-alphaSRII were all significantly (p < 0.001) higher in patients with DHF and SHF than in healthy volunteers. All markers of systemic inflammation were independently associated with the presence of clinical CHF.

CONCLUSION

Insulin resistance and inflammatory activation are present in older patients with SHF and DHF.

The Role of Exercise in the Treatment of Cardiovascular Disease Associated with Type 2 Diabetes Mellitus

The role of exercise training in the prevention and treatment of type 2 diabetes mellitus has been studied extensively over the past two decades. Although the primary treatment aim for patients with type 2 diabetes is metabolic control, the morbidity and mortality associated with the disease is more a function of cardiovascular disease. As exercise is associated with favourable reductions in the risk for cardiovascular disease in other high-risk populations, here we explore the role of exercise in the treatment of cardiovascular maladaptations associated with type 2 diabetes. The cardiovascular adaptation to type 2 diabetes is characterised by hypertrophy, stiffening and loss of functional reserve. Clinically, the cardiovascular adaptations to the diabetic state are associated with an increased risk for cardiovascular disease. Functionally, these adaptations have been shown to contribute to a reduced exercise capacity, which may explain the reduced cardiovascular fitness observed in this population. Exercise training is associated with improved exercise capacity in various populations, including type 2 diabetes. Several structural and functional adaptations within the cardiovascular system following exercise training could explain these findings, such as reductions in ventricular and vascular structural hypertrophy and compliance coupled with increased functional reserve. Although these cardiovascular adaptations to aerobic exercise training have been well documented in older populations with similar decrements in cardiovascular fitness and function, they have yet to be examined in patients with type 2 diabetes. For this reason, we contend that exercise training may be an excellent therapeutic adjunct in the treatment of diabetic cardiovascular disease.

Hospital and 1-year outcome after acute myocardial infarction in patients with diabetes mellitus and hypertension

Hypertension (HT) and diabetes mellitus (DM) lead to structural and functional cardiac impairment and worsen the prognosis after myocardial infarction (MI). However, the prognosis of male or female patients with the coexistence of HT and DM after MI has not been clearly demonstrated. The study sample comprised 4317 consecutive patients with an acute MI from a prospective nationwide survey conducted in 1992, 1994 and 1996 in all 25 coronary care units operating in Israel. The in-hospital, 30-day and 1-year outcome of diabetic hypertensive patients (n=546) was compared with that of diabetic normotensive patients (n=547) and with that of nondiabetic hypertensive patients (n=1192) and nondiabetic normotensive subjects (n=2032). The crude in-hospital, 30-day and 1-year mortality rates of diabetic hypertensive patients (11.7, 16.5 and 27.6%, respectively) were significantly higher than those of the diabetic normotensive patients (9.5, 15.4 and 22.9%, respectively) and nondiabetic hypertensive patients (7.1, 11.6 and 17.6%, respectively). Kaplan-Meier survival curves showed increased mortality rates during the 1-year follow-up in diabetic hypertensive patients. Adjusted risk for 1-year mortality was increased in diabetic patients. However, the risk was similar in diabetic hypertensive and normotensive patients (hazard ratio (HR) 1.55, 95% confidence interval (CI) 1.25-1.93, and 1.62, 95% CI 1.29-2.04, respectively). Adjusted Kaplan-Meier survival curves of diabetic hypertensive patients converged with those of the diabetic normotensives. The existence of DM increases the 1-year mortality after MI by about 60%. However, controlled hypertension did not worsen the outcome of diabetic male or female patients after MI.

Left ventricular mass is not related to insulin sensitivity in never-treated primary hypertension

OBJECTIVE

Insulin has been suggested to promote myocardial cell growth and the development of left ventricular (LV) hypertrophy. This study examines the possible relationship between LV mass and insulin sensitivity.

DESIGN

Previously untreated non-diabetic hypertensive patients.

PATIENTS

Fifty-one patients with mean age 51 +/- 8 years, body mass index (BMI) 25.9 +/- 3.2 kg/m2 and blood pressure 158/102 mmHg were included. LV mass was determined by echocardiography. Glucose metabolism was assessed by an euglycemic insulin clamp (40 mU/m2 body surface area/min).

RESULTS

Insulin sensitivity index (MI) and insulin clearance were inversely related to LV mass (r = -0.37, P < 0.01 and -0.33, P < 0.05, respectively) and LV mass indexed to height (r = -0.33, P < 0.05 and -0.29, P < 0.05, respectively). C-peptide and fasting insulin were related to LV mass (r = 0.33, P < 0.05 and r = 0.36, P < 0.01, respectively) and LV mass indexed to height (r = 0.30, P < 0.05 and r = 0.34, P < 0.05, respectively). In contrast, when LV mass was indexed by body surface area there was no longer a relation to MI, insulin clearance, C-peptide or fasting insulin. When adjusting for BMI in a multiple regression analysis, MI and LV mass no longer showed a relation. Indeed, MI, insulin clearance, C-peptide and insulin were all strongly related to weight and BMI.

CONCLUSION

Insulin sensitivity is related to body size in untreated hypertension. However, insulin sensitivity is not related to LV mass, if adjusting for body size. This does not support a direct growth-promoting effect of insulin on the myocardium. Insulin does not appear to be strongly involved in development of hypertensive LV hypertrophy.

Impaired glucose tolerance as a determinant of early deterioration of left ventricular diastolic function in middle-aged healthy subjects

To clarify the determinants of an abnormal relaxation diastolic pattern assessed by Doppler echocardiography, 131 middle-aged healthy subjects were analyzed. By multivariate logistic regression analysis, fasting insulin levels (p = 0.0016) and peak glucose levels (p = 0.046) were independent predictors of an abnormal relaxation diastolic pattern 2 hours after 75 g OGTT.

Insulin and diastolic dysfunction in lean and obese hypertensives: genetic influence

We investigated the influence of genetic predisposition to hypertension by studying the relation between insulin sensitivity and left ventricular (LV) mass and function in untreated lean and obese hypertensives. We selected 50 lean hypertensives with normotensive parents (negative family history of hypertension [F-]), 64 lean hypertensives with 1 or both parents hypertensive (positive family history of hypertension [F+]), 40 obese F- hypertensives, and 43 obese F+ hypertensives. The 4 groups were comparable regarding age, gender, 24-hour blood pressure profile, and known duration of hypertension. We measured glucose, insulin, and C-peptide during fasting and during an oral glucose tolerance test; LV morphology and function were assessed by digitized M-mode echocardiography. Glucose (fasting and test) levels were normal in all and similar among the 4 groups. Insulin and C-peptide (fasting and stimulated) levels were higher in obese hypertensives than in lean hypertensives; at similar body mass index, insulin and C-peptide levels were higher in F+ than in F- groups. Compared with lean hypertensives, obese hypertensives had greater LV mass index; LV systolic function was normal in all and similar among the groups. The indices of LV diastolic function were significantly lower in F+ than in F- groups. LV mass index did not correlate with metabolic parameters; the indices of LV diastolic function were inversely correlated with insulin area during test in only the 2 F+ groups. In conclusion, genetic predisposition to hypertension is associated with a reduced insulin sensitivity and affects the response of the myocardium to increased insulin levels, inducing a greater impairment of diastolic function. Insulin sensitivity and genetic predisposition to hypertension seem to have no influence on LV mass.

Effect of insulin resistance on left ventricular hypertrophy and dysfunction in essential hypertension

BACKGROUND

In hypertensive patients, the relationships between glucose tolerance and left ventricular hypertrophy (LVH) and left ventricular diastolic function (LVDF) have been described in several reports.

OBJECTIVE

In this study, we examined the relationships between insulin resistance and LVH and LVDF in hypertensive patients from the therapeutic perspective.

METHODS AND RESULTS

The study participants were essential hypertensive patients with impaired glucose tolerance (IGT-HT, n = 26), hypertensive patients with normal glucose tolerance (NGT-HT, n = 39), and normotensive control individuals (n = 18). Insulin resistance was evaluated by the insulin suppression test by use of the steady-state plasma glucose (SSPG) level. Left ventricular mass index (LVMI) and LVDF, which was determined by the E:A ratio, were estimated by echocardiography. Temocapril, an angiotensin-converting enzyme inhibitor, was administered in an open, non-randomized manner with a mean dose of 2.8+/-0.2 mg/ day, and the mean administration period was 18 weeks. The systolic and diastolic blood pressure, the LVMI, and the SSPG level were significantly higher in the hypertensive patients than in the control individuals. The mean systolic and diastolic blood pressures were significantly decreased by treatment with Temocapril. Before treatment, stepwise regression analysis showed that SSPG is an independent predictor for LVMI and LVDF. After treatment, the changes in LVMI (D-LVMI; %) (-15.1+/-1.5), the changes in LVDF (D-E:A; %) (-38.2+/-4.1), and the changes in insulin resistance (D-SSPG; %) (-13.7+/-1.7) were significantly higher in the IGT-HT group than in the NGT-HT group (-11.4+/-1.1, -18.1+/-1.7, -9.4+/-1.4, respectively), and the D-SSPG was an independent predictor for D-LVMI and D-E :A.

CONCLUSIONS

The results of this study indicate that insulin resistance is an important factor affecting LVH and LVDF.

Insulin effects on the left ventricle in older hypertensive subjects

BACKGROUND

To evaluate the effects of hyperinsulinemia on left ventricular (LV) structure and function in older hypertensive subjects

METHODS

Thirty-seven hypertensive subjects (17 men/20 women) aged 50 to 80, were studied. LV mass were evaluated echocardiographically according to the Penn convention. A 75-g oral glucose tolerance test (OGTT) was performed after overnight fasting, and both blood glucose and insulin concentrations were assayed at 0, 30, 60, 90, 120, and 180 minutes. Comparison between groups was performed by analysis of variance. A P value of .05 was considered statistically significant.

RESULTS

When the hypertensive patients were divided into two groups according to the median value of 2-hour post-loading plasma insulin, there was no difference in blood pressure levels between the groups. However, hyperinsulinemic hypertensive subjects had an increased LV mass (P < .05), mean wall thickness, and interventricular septum thickness (P < .05 for both parameters) and had better systolic function-ejection and shortening fractions (P < .0001 for both indices).

CONCLUSIONS

Hyperinsulinemia may be associated with increased left ventricular mass and with a better systolic performance in older hypertensive subjects.

Relation among left ventricular mass, insulin resistance, and blood pressure in nonobese subjects

Because left ventricular (LV) mass (LVM) is a powerful predictor of future cardiovascular events, it is important to identify hemodynamic and nonhemodynamic factors that increase LVM. We studied the separate contribution to LVM of daily arterial blood pressure (BP) and insulin resistance in a consecutive series of 29 (mean+/-SD age, 43+/-13 yr) nonobese (body mass index, 24+/-1.8 kg/m2), nondiabetic, glucose-tolerant subjects with untreated borderline or mild hypertension. The insulin sensitivity index (SI) was quantitatively determined from the frequently sampled iv glucose tolerance test. BP was characterized by ambulatory 24-h BP monitoring, and LVM index (LVMI) was determined by two-dimensional directed M-mode echocardiography. LVMI was directly related to 24-h mean BP (r=0.47; P=0.01). LMVI was also significantly related to Si (r=-0.43; P=0.02). In this nonobese group, neither LVMI nor Si was related to body mass index or age. After adjustment for the influence of BP on LVMI, a significant relation remained between LVMI and Si (P < 0.05). We conclude that in nonobese subjects with high normal BP, insulin sensitivity is related to LVM independently of BP and may be an important modulator of LV growth. In addition to a reduction of arterial BP, optimal prevention of LV hypertrophy in hypertensives may require improved insulin sensitivity.

Canadian consensus recommendations for the measurement and reporting of diastolic dysfunction by echocardiography: from the Investigators of Consensus on Diastolic Dysfunction by Echocardiography

Abnormalities of diastolic filling are increasingly recognized as a cause of symptoms and predictors of outcome in patients with most forms of heart disease. Noninvasive assessment of diastolic filling is possible in almost all patients, but accurate evaluation must relate echocardiographic Doppler measurements to the complex physiologic and hemodynamic factors responsible for normal and abnormal filling. This evaluation has been facilitated by recent correlation of Doppler measurement of mitral and pulmonary venous inflow with hemodynamic studies. These studies have confirmed that when a careful, integrated approach is taken, Doppler flow patterns can document a progressive pattern of abnormality in many conditions. Impaired left ventricular (LV) relaxation is seen early and is recognized by a decrease in early transmitral LV filling and an increased proportion of filling during atrial contraction. As abnormalities progress, increasing LV chamber stiffness and elevated left atrial pressure lead to a "pseudonormal" filling pattern that previously has caused considerable confusion. This can be unmasked by careful evaluation of pulmonary venous inflow and the use of the Valsalva maneuver. When marked diastolic abnormalities are present, LV filling has restrictive features characterized by rapid early filling, a very stiff left ventricle with high filling pressures, and a poor prognosis. Routine measurement of indexes of diastolic filling have been hampered by uncertainty as to what should be measured, what techniques should be used, definition of normal values, and a clear method of reporting findings. This report represents the efforts of a Canadian consensus group to define a national standard for the performance and reporting of echocardiographic Doppler studies of diastolic filling.

Hyperinsulinemia and left ventricular geometry in a work-site population in Japan

The present study was designed to test whether hyperglycemia or hyperinsulinemia influences left ventricular mass and geometry. An echocardiogram and 75-g oral glucose tolerance test were performed in 210 normotensive and 180 mildly to moderately hypertensive male workers in a bus company who were free from cardiac diseases and were not taking medication for hypertension and diabetes mellitus. When we divided subjects into four groups according to the left ventricular geometric pattern using left ventricular mass index of 110 g/m2 and relative wall thickness (ratio of 2 x posterior wall thickness to end-diastolic left ventricular diameter) of 0.44, body mass index and systolic blood pressure were higher in those with concentric hypertrophy and eccentric hypertrophy. In addition, hemoglobin A(Ic) level and the sum of fasting and 2-hour postload serum glucose levels were higher in subjects with concentric hypertrophy. In subjects without diabetes mellitus (n=336), 2-hour postload serum insulin level and the sum of fasting and 2-hour postload serum insulin levels tended to be higher in those with concentric hypertrophy and concentric remodeling. In multiple regression analysis, the sum of glucose levels (or hemoglobin A(Ic) level) in all subjects and the sum of insulin (or 2-hour postload insulin) levels in subjects without diabetes mellitus significantly correlated with relative wall thickness, independent of age, systolic blood pressure, and body mass index. Neither glucose nor insulin levels correlated with left ventricular mass index. Our results suggest that hyperglycemia and hyperinsulinemia may promote concentric changes in the left ventricle in normotensive and mildly to moderately hypertensive men.