Relationship between intima-media thickness of the common carotid artery and arterial stiffness in subjects with and without type 2 diabetes: a case-series report

Detrimental effects of physical inactivity on peripheral and brain vasculature in humans: Insights into mechanisms, long-term health consequences and protective strategies

The growing prevalence of physical inactivity in the population highlights the urgent need for a more comprehensive understanding of how sedentary behaviour affects health, the mechanisms involved and what strategies are effective in counteracting its negative effects. Physical inactivity is an independent risk factor for different pathologies including atherosclerosis, hypertension and cardiovascular disease. It is known to progressively lead to reduced life expectancy and quality of life, and it is the fourth leading risk factor for mortality worldwide. Recent evidence indicates that uninterrupted prolonged sitting and short-term inactivity periods impair endothelial function (measured by flow-mediated dilation) and induce arterial structural alterations, predominantly in the lower body vasculature. Similar effects may occur in the cerebral vasculature, with recent evidence showing impairments in cerebral blood flow following prolonged sitting. The precise molecular and physiological mechanisms underlying inactivity-induced vascular dysfunction in humans are yet to be fully established, although evidence to date indicates that it may involve modulation of shear stress, inflammatory and vascular biomarkers. Despite the steady increase in sedentarism in our societies, only a few intervention strategies have been investigated for their efficacy in counteracting the associated vascular impairments. The current review provides a comprehensive overview of the evidence linking acute and short-term physical inactivity to detrimental effects on peripheral, central and cerebral vascular health in humans. We further examine the underlying molecular and physiological mechanisms and attempt to link these to long-term consequences for cardiovascular health. Finally, we summarize and discuss the efficacy of lifestyle interventions in offsetting the negative consequences of physical inactivity.

Dyslipidemia, Insulin Resistance, Ectopic Lipid Accumulation, and Vascular Function in Resistance to Thyroid Hormone β

PURPOSE

In resistance to thyroid hormone due to mutations in thyroid hormone receptor β, peripheral tissues are variably refractory to the action of circulating thyroid hormones. We evaluated parameters contributing to atherosclerotic risk in this disorder.

METHODS

We measured low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), nonesterified fatty acids (NEFA), intrahepatic lipid (IHL) and intramyocellular lipid (IMCL), Homeostasis-model assessment of insulin resistance (HOMA-IR), augmentation index (AIx) and pulse wave velocity (PWV), flow-mediated dilatation, and carotid intima-media thickness (cIMT) in an unselected, genetically confirmed cohort of adult RTHβ patients (n = 27-77) and compared these with measurements in healthy subjects (up to n = 100) and thyrotoxic patients (n = 40).

RESULTS

Resistance to thyroid hormone beta (RTHβ) patients exhibited higher LDL-C (P = 0.008) and TG (P = 0.002) and lower HDL-C concentrations (P = 0.015 × 10-2) than control subjects, with LDL-C being higher than in thyrotoxic patients with comparable hyperthyroxinemia. Proprotein convertase subtilisin/kexin 9 (P = 0.002) and apolipoprotein B (P = 0.0009) levels were reduced in thyrotoxic patients but not lower in RTHβ patients or control subjects. Intrahepatic lipid (P = 0.02 × 10-4), IMCL (P = 0.002), HOMA-IR (P = 0.01 × 10-2), and NEFA (P = 0.04 × 10-6) were significantly higher in RTHβ patients than control subjects. Flow-mediated dilatation was increased (P = 0.04) but cIMT (P = 0.71), PWV P = 0.81), and AIx (P = 0.95) were unaltered in RTHβ patients.

CONCLUSIONS

We have documented mixed dyslipidemia with hepatic and IMCL accumulation in RTHβ, suggesting that surveillance for these metabolic abnormalities is warranted. How they combine with enhanced endothelial function and unaltered vessel wall thickness and compliance to determine overall cardiometabolic risk in this disorder remains to be defined.

Effect of present versus previous smoking on non-invasive haemodynamics

We examined cardiovascular function in 637 volunteers (19-72 years) without antihypertensive medication in never smokers (n = 365), present smokers (n = 81) and previous smokers (n = 191, median abstinence 10 years). Haemodynamics during passive head-up tilt were recorded using whole-body impedance cardiography and radial pulse wave analysis. Results were adjusted for age, sex, body mass index, LDL cholesterol and alcohol use. Systolic and diastolic blood pressure, heart rate, and pulse wave velocity were not different between the groups. Supine aortic reflection times did not differ, while upright values were shorter in present versus previous smokers (p = 0.04). Heart rate adjusted augmentation index was increased in the supine position in present smokers versus controls (p = 0.045), and in present (p < 0.001) and previous (p = 0.031) smokers versus controls in the upright position. Supine and upright cardiac output was higher (p ≤ 0.016) and systemic vascular resistance lower (p ≤ 0.001) in present versus previous smokers. In spite of the long abstinence, in the upright position previous smokers had lower cardiac output (p = 0.032) and higher systemic vascular resistance (p = 0.014) than never smokers. In the absence of differences in blood pressure and arterial stiffness, present smokers presented with hyperdynamic circulation and enhanced wave reflection compared with previous smokers.

Increased carotid-femoral pulse wave velocity and common carotid artery intima-media thickness obtained to assess target organ damage in hypertensive patients are closely related

BACKGROUND

Increased carotid-femoral pulse wave velocity (CF-PWV) and increased carotid intima-media thickness (IMT) in hypertension (HT) patients are indicators of asymptomatic organ damage. The relationship between carotid IMT and CF-PWV has been shown; studies comparing CF-PWV and IMT values within different vascular regions are limited. We aimed to investigate the relationship between IMT value measured from different anatomical regions and CF-PWV, and the localization of IMT that determines increased CF-PWV best.

METHODS

This study included 312 patients with HT. CF-PWV measurements with Doppler ultrasonography (USG). Vascular IMTs were measurements of common-internal carotid, brachial, and femoral arteries with B-mode USG (CC-IMT, IC-IMT, B-IMT, and F-IMT, respectively). Patients were divided into two groups according to their CF-PWV value (Increased CF-PWV >10 m/s and normal CF-PWV ≤10m/s).

RESULTS

Increased CF-PWV was detected in 54 (17.3%) of HT patients. The patient group with increased CF-PWV was older, and their CC-IMT, IC-IMT and F-IMT values were found to be higher. The other 3 IMT increases excluding B-IMT were closely related to the CF-PWV increase. Only age and CC-IMT values were found to be most closely related to CF-PWV. CC-IMT and age were found to be independently associated with increased CF-PWV. CC-IMT (each-0.1 mm) and age (each year) were found to augment the development of increased CF-PWV by 50.3% and 14.6%, respectively.

CONCLUSION

There is a close relationship between CC-IMT and CF-PWV increase in HT. It was thought that it would still be more useful to look at the increase of CC-IMT compared to other vascular regions for screening asymptomatic organ damage.

Risk allele of gene variant rs6584389 is associated with increased intima-media thickness in patients with type 2 diabetes

BACKGROUND

Genome-wide association studies identified several gene variants associated with peripheral arterial disease (PAD). Among them, rs6584389 A>C was significantly associated with PAD defined by decreased ankle-brachial index (ABI). The aim of this study was to investigate whether the rs6584389 variant is also associated with the earlier stages of atherosclerosis assessed by intima-media thickness (IMT) or pulse-wave velocity (PWV) in clinically asymptomatic subjects with type 2 diabetes (T2DM), a group of patients with a high cardiovascular risk.

PATIENTS AND METHODS

In total, 111 patients with T2DM (56 females, 55 males) with a mean age 63.0 ± 9.1 years were consecutively included in the study. IMT was measured by ultrasound using 7 MHz linear transducer. PWV was measured using a piezoelectric method. Genotyping for rs6584389 was performed by PCR-HRMA method.

RESULTS

The carriers of the risk C-allele of rs6584389 variant had significantly higher mean left-side IMT (AA: 0.67 ± 0.12, AC 0.77 ± 0.21, CC 0.78 ± 0.22 mm; p = 0.04). In multiple linear regression analysis, rs6586389 genotype was significantly associated with all measured IMT parameters. The presence of each risk C-allele predicted an increase in left-side IMT by 0.056 mm (p = 0.017), right-side IMT by 0.053 mm (p = 0.039), average IMT by 0.054 mm (p = 0.023), and maximal IMT by 0.058 mm (p = 0.021). Age and HbA1c levels were also significantly associated with increased IMT in all multivariate models.

CONCLUSIONS

Gene variant rs6584389 A>C near to PAX2 gene was associated with increased carotid IMT in patients with type 2 diabetes independently of the other main risk factors for atherosclerosis.

A randomised study of the impact of the SGLT2 inhibitor dapagliflozin on microvascular and macrovascular circulation

Background

The sodium–glucose cotransporter 2 inhibitor, dapagliflozin, has been shown to improve diabetic control and reduce blood pressure in patients with type 2 diabetes mellitus. Its effects on micro- and macrovascular structure and function have not yet been reported.

Methods

This was a prospective, single-centre, placebo-controlled, double-blind, randomised crossover phase IIIb study conducted between March 2014 and February 2015. After a 4-week run-in/washout phase, patients (N = 59) received 6 weeks of either dapagliflozin 10 mg or placebo once daily. They then underwent a 1-week washout before crossing over to the other treatment. Changes in retinal capillary flow (RCF) and arteriole remodelling were evaluated using scanning laser Doppler flowmetry, while micro- and macrovascular parameters in the systemic circulation were assessed using pulse wave analysis.

Results

Six weeks of dapagliflozin treatment resulted in improvements in diabetes control, including blood glucose and insulin resistance, and reduced office and 24-h ambulatory blood pressure values. RCF decreased from 324 AU at baseline to 308 AU after treatment with dapagliflozin (p = 0.028), while there was little difference after the placebo (318 AU; p = 0.334). Furthermore, the arteriole remodelling that was seen after the placebo phase was not evident after the dapagliflozin phase. Central systolic and diastolic blood pressure values were significantly lower after 6 weeks of dapagliflozin, by 3.0 and 2.2 mmHg, respectively (p = 0.035 and 0.020, respectively vs. baseline).

Conclusions

Six weeks of dapagliflozin treatment resulted in numerous beneficial effects. In addition to achieving superior diabetes control and blood pressure, parameters associated with the early stages of vascular remodelling were also improved.

Trial registrationhttp://www.clinicaltrials.gov (NCT02383238)

Arterial indices and serum cystatin C level in individuals with occupational wide band noise exposure

BACKGROUND

Chronic exposure to noise is known to cause a wide range of health problems including extracellular matrix (ECM) proliferation and involvement of cardiovascular system. There are a few studies to investigate noise-induced vascular changes using noninvasive methods. In this study we used carotid artery intima-media thickness (CIMT) and aortic augmentation as indices of arterial properties and cystatin C as a serum biomarker relating to ECM metabolism.

MATERIALS AND METHODS

Ninety-three male participants were included in this study from aeronautic technicians: 39 with and 54 without a history of wide band noise (WBN) exposure. For better discrimination, the participants were divided into the two age groups: <40 and >40 years old. Adjusted aortic augmentation index (AI) for a heart rate equal to 75 beats per minute (AIx@HR75) were calculated using pulse wave analysis (PWA). CIMT was measured in 54 participants who accepted to undergo Doppler ultrasonography. Serum cystatin C was also measured.

RESULTS

Among younger individuals the mean CIMT was 0.85 ± 0.09 mm and 0.75 ± 0.22 mm in the in the exposed and the control groups respectively. Among older individuals CIMT had a mean of 1.04 ± 0.22 mm vs. 1.00 ± 0.25 mm for the exposed vs. the control group. However, in both age groups the difference was not significant at the 0.05 level. A comparison of AIx@HR75 between exposure group and control group both in younger age group (5.46 ± 11.22 vs. 8.56 ± 8.66) and older age group (17.55 ± 10.07 vs. 16.61 ± 5.77) revealed no significant difference. We did not find any significant correlation between CIMT and AIx@HR75 in exposed group (r = 0.314, P value = 0.145) but the correlation was significant in control group (r = 0.455, P value = 0.019). Serum cystatin C level was significantly lower in individuals with WBN exposure compared to controls (441.10 ± 104.70 ng/L vs. 616.89 ± 136.14, P value < 0.001) both in younger and older groups.

CONCLUSION

We could not find any evidence for the association of WBN exposure with arterial properties, but cystatin C was significantly lower in the exposed group.

The relationship between HbA₁c and ultrasound plaque textures in atherosclerotic patients

Objective

Diabetes mellitus (DM) is associated to the morphological and componential characteristics of atheromatous plaques. It has proven that plaque textures are related to plaque components and beneficial for atherosclerotic risk stratification. The aim of this study is to compare plaque textures in patients with and without DM, and examine the relationship between HbA_1c levels and the ultrasound plaque textures in atherosclerotic patients.

Methods

A total of 136 participants (among them 66 are diabetic and 70 are non-diabetic) suffering from carotid plaques were included. About 300 texture features were extracted from the ultrasound images of plaques using the algorithms of histogram, absolute gradient, run-length matrix, gray-level co-occurrence matrix, autoregressive model and wavelet transform, respectively. Thirty optimal features were selected by the Fisher coefficient and the mutual information measure. The most discriminating feature (MDF) was obtained from the linear discriminant analysis for the optimal features. Linear regression model was performed to investigate the relationship between HbA_1c and MDF. The receiver operating characteristics (ROC) curve was further developed to validate the relation between the estimated HbA_1c (models output) and diabetes status.

Results

A total of 12 texture features showed statistical difference between patients with and without DM. The MDF was significant higher in non-diabetic patients (0.326 ± 0.049) than diabetic patients (−0.346 ± 0.052) (p < 0.001). The optimal regression model (r = 0.348, p < 0.001) for HbA_1c included a constant (p < 0.001) and the MDF (p < 0.001). The areas under ROC curve used to estimate HbA_1c was 0.828.

Conclusions

The results indicate that there is a quantitative relationship between the HbA_1c levels and plaque textures in ultrasonic images of atherosclerotic patients, which may suggest that texture analysis of the ultrasonic image of plaque is a promising method for evaluating the cardiovascular risk caused by DM in patients with plaques.

Ambulatory arterial stiffness index is not associated with magnetic resonance imaging markers of cerebral small vessel disease in lacunar stroke patients

Ambulatory arterial stiffness index (AASI) is associated with microvascular damage in other organs, but the association with microvascular brain damage is unknown. The association of AASI with magnetic resonance imaging (MRI) markers of cerebral small vessel disease in 143 patients with lacunar stroke was investigated. We performed 24-hour ambulatory blood pressure monitoring and scored the presence of lacunes, white matter hyperintensities, perivascular spaces, and cerebral microbleeds on brain MRI. In logistic regression analyses, AASI was associated with white matter hyperintensities, but, after adjustment for age and sex, this association lost significance. AASI was not associated with lacunes, microbleeds, or perivascular spaces. Systolic and diastolic 24-hour blood pressure values were associated with lacunes, perivascular spaces, and microbleeds independent of age and sex. Despite its significance and growing interest as a possible prognostic and therapeutic target in (micro)vascular diseases, AASI seems to have no added value over standard 24-hour blood pressure in cerebral small vessel disease.

Ambulatory arterial stiffness index is associated with impaired left atrial mechanical functions in hypertensive diabetic patients: A speckle tracking study

Objective:

The ambulatory arterial stiffness index has been proposed as an indicator of arterial stiffness. The aim of this study was to test the hypothesis that increased ambulatory arterial stiffness index might be related with impaired left atrial function in hypertensive diabetic patients with no previous history of cardiovascular disease.

Methods:

Inclusion criteria included office systolic BP> 130 mm Hg or diastolic BP> 80 mm Hg and absence of secondary causes of HT, whereas exclusion criteria LV ejection fraction <50%, history of significant coronary artery disease, chronic renal failure, atrial fibrillation/flutter, second or third-degree atrioventricular block, moderate to severe valvular heart disease, history of cerebrovascular disease, non-dipper hypertensive pattern and sleep apnea. The study was composed of 121 hypertensive diabetic patients. Twenty-four-hour ambulatory blood pressure monitoring and echocardiography were performed in each patient. The relationship between ambulatory arterial stiffness index and left atrial functions was analyzed. AASI was calculated as 1 minus the regression slope of diastolic BP plotted against systolic BP obtained through individual 24-h ABPM.

Results:

The univariate analysis showed that ambulatory arterial stiffness index was positively correlated with age (r=:0.287, p=:0.001), hypertension duration (r=:0.388, p<0.001), fasting plasma glucose (r=:0.224, p=:0.014), HbA1c (r=:0.206, p=:0.023), LDL cholesterol (r=:0.254, p=:0.005), and also overall pulse pressure (r=:0.195, p=:0.002), office-pulse pressure (r=:0.188, p=:0.039), carotid intima-media thickness (r=:0.198, p=:0.029), E/E’ (r=:0.248, p=:0.006), and left atrial volume index (r=:0.237, p=:0.009). Moreover, ambulatory arterial stiffness index was negatively correlated with eGFR (r=:(-) 0.242, p=:0.008), peak left atrial strain during ventricular systole [S-LAs (r=:(-) 0.654, p<0.001)], peak left atrial strain at early diastole [S-LAe (r=:(-)0.215, p=:0.018)], and peak left atrial strain rate during ventricular systole [SR-LAs (r=:(-) 0.607, p<0.001)]. The multiple linear regression analysis showed that ambulatory arterial stiffness index was independently associated with peak left atrial strain rate during ventricular systole (SR-LAs) (p<0.001).

Conclusion:

In hypertensive diabetic patients, increased ambulatory arterial stiffness index is associated with impaired left atrial functions, independent of left ventricular diastolic dysfunction.

Ambulatory arterial stiffness index correlates with ambulatory pulse pressure but not dipping status in patients with grade 1/grade 2 essential hypertension

OBJECTIVE

To evaluate the relationship between ambulatory arterial stiffness index (AASI) and other parameters derived from ambulatory blood pressure (BP) monitoring, including dipping status, in patients with grade 1/grade 2 hypertension.

METHODS

This retrospective analysis included baseline data from Chinese outpatients enrolled into a previous study, who had clinic diastolic BP of 90-109 mmHg and systolic BP <180 mmHg, had undergone 24-h ambulatory BP monitoring and routine blood chemistry investigations, and had estimated glomerular filtration rate (eGFR) data.

RESULTS

Out of 120 patients screened, 87 were included. No significant difference in 24-h AASI was found between dippers and nondippers. The 24-h AASI significantly correlated with age, systolic BP and pulse pressure, and inversely correlated with 24-h diastolic BP variation and eGFR. In dippers and nondippers, AASI correlated with daytime pulse pressure, daytime diastolic BP variation and eGFR; in nondippers, AASI also correlated with 24-h systolic BP and 24-h pulse pressure. The 24-h AASI was significantly associated with 24-h pulse pressure and daytime pulse pressure.

CONCLUSION

In patients with grade 1/grade 2 essential hypertension, AASI shows a significant correlation with ambulatory pulse pressure.

Association between serum uric acid, hypertension, vascular stiffness and subclinical atherosclerosis: data from the Brisighella Heart Study

OBJECTIVE

Serum uric acid (SUA) levels correlate with many recognized cardiovascular risk factors, including age, male sex, hypertension, diabetes mellitus, hypertriglyceridemia, obesity, and insulin resistance. The aim of our study was to verify in a large well characterized population sample the relationship between SUA values, hypertension, arterial stiffness and subclinical atherosclerosis.

METHODS

For this study, we selected 248 men and 371 women adult patients enrolled in the last Brisighella Heart Study population survey for which a full set of data were available and not consuming antihypertensive, antidiabetic, lipid-lowering and uric acid-lowering drugs. SUA and other available variables were related to blood pressure level, carotid-femoral pulse wave velocity (cfPWV) and carotid intima-media thickness (cIMT).

RESULTS

Hypertension prevalence was strongly related to SUA quartiles: we found significant differences between the 2nd (23.0%) and the 3rd quartiles (36.4%; P vs. 2nd < 0.05), and between the 3rd and the 4th quartile (56.3%; P vs. 3rd < 0.05). Similarly, the metabolic syndrome prevalence increased significantly at 39.5% in the 3rd SUA quartile (P < 0.05 vs. 2nd) and at 58.9% in the 4th quartile (P < 0.05 vs. 3rd). Intima-media thickness gradually and significantly rose along quartiles of SUA (P for trend < 0.0001), in particular, it was 0.86  mm in the 1st quartile, 0.90 in the 2nd, 0.94 in the 3rd, and 0.97 in the last quartile, with significant differences between each quartiles (all P < 0.05). In multivariate regression analyses, SUA resulted to be significantly associated to hypertension and metabolic syndrome prevalence, and IMT. Even if a significant association between SUA and cfPWV was found in univariate analysis (P = 0.002), when adjusting for age, the trend became nonsignificant (0.20).

CONCLUSION

In the studied population sample, after adjustment for a large number of parameters, SUA appears to be significantly correlated to hypertension and IMT, but not to aortic stiffness.

Arterial stiffness estimation in healthy subjects: a validation of oscillometric (Arteriograph) and tonometric (SphygmoCor) techniques

Arterial stiffness is an important cardiovascular risk marker, which can be measured noninvasively with different techniques. To validate such techniques in healthy subjects, we compared the recently introduced oscillometric Arteriograph (AG) technique with the tonometric SphygmoCor (SC) method and their associations with carotid ultrasound measures and traditional risk indicators. Sixty-three healthy subjects aged 20-69 (mean 48 ± 15) years were included. We measured aortic pulse wave velocity (PWVao) and augmentation index (AIx) by AG and SC, and with SC also the PWVao standardized to 80% of the direct distance between carotid and femoral sites (St-PWVaoSC). The carotid strain, stiffness index and intima-media thickness (cIMTmean) were evaluated by ultrasound. PWVaoAG (8.00 ± 2.16 m s(-1)) was higher (P<0.001) than PWVaoSC (6.87 ± 1.47 m s(-1)), but did not differ from St-PWVaoSC (7.68 ± 1.58 m s(-1)), and correlated (P<0.001) with both (r = 0.54 and 0.59). St-PWVaoSC was significantly (P < 0.01) higher than PWVaoAG for values below median (7.4 m s(-1)). PWVao by SC and AG differed significantly in females (P<0.001), but not in males (P=0.40). AIxaoAG (27.5 ± 14.5%) was higher (P < 0.001) than AIxaoSC (20.5 ± 17.4%), but related closely (r=0.97, P<0.001). St-PWVaoSC, PWVao and AIxao by SC, and PWVao and AIxao by AG were all related to serum cholesterol and to cIMTmean (P<0.001). Arterial stiffness indices by AG and SC correlate with vascular risk markers in healthy subjects. AIxao results by AG and SC are closely interrelated, but higher values are obtained by AG. In the lower range, PWVao values by AG and SC are similar, but differ for higher values. Our results imply the necessity to apply one and the same technique for repeated studies.

Evaluation of carotid artery elasticity changes in patients with type 2 diabetes

BACKGROUND

Type 2 diabetes is one of the most common causes of cardiovascular disease as it causes arterial stiffness changes. The purpose of this study is to characterize, in vivo, carotid arterial structural and functional changes by applying radio frequency and X-strain ultrasound techniques.

METHODS

Ninety-one subjects were assigned into two groups; a diabetes group and a control group. Structural and functional changes in the common carotid arterial wall were investigated by quality intima-media thickness (QIMT), quality arterial stiffness (QAS), and X-strain analysis with a Mylab Twice ultrasound instrument. The relationships among variables between the two groups were analyzed in this study.

RESULTS

There was no significant difference in carotid IMT (626.5 ± 169.1 μm vs. 568.5 ± 122.6 μm, P = 0.1506) between two groups. Pulse wave velocity (PWV) and stiffness index (β) were remarkably greater (8.388 ± 3.254 m/s vs. 7.269 ± 1.332 m/s; 12.51 ± 14.16 vs.9.279 ± 2.871), while compliance coefficient (CC) decreased significantly in the diabetes group (0.802 ± 0.3094 mm2/Kpa vs. 0.968 ± 0.3992 mm2/Kpa) (P < 0.05). The displacement difference of radial (RD-D), longitudinal (LD-D) and rotation (ROT-D) directions were significantly different between two groups' comparison (P = 0.0212, P = 0.0235 and P = 0.0072, respectively). The time of circumferential peak strain difference (CS-DT) and the time of radial peak strain rate (RSR-T) were found to be significantly different between the two groups (341.9 ± 77.56 ms vs. 369.0 ± 78.26 ms, P = 0.0494; 142.7 ± 22.43 ms vs. 136.2 ± 30.70 ms, P = 0.0474). CS-TD and RSR-T were also found to be positively correlated with CC value (r = 0.3908, P < 0.005 and r = 0.3027, P = 0.0326, respectively). Finally, PWV was negatively correlated with CC with (r = -0.6177, P < 0.001).

CONCLUSIONS

In type 2 diabetes, the functional changes in CCA can be identified using the methods presented in this article earlier than the structural changes. Arterial stiffness values provided by QAS and X-strain analysis can be used as indicators of CCA functional lesions in patients with type 2 diabetes.

Correlation between arterial wall stiffness, N-terminal prohormone of brain natriuretic peptide, functional and structural myocardial abnormalities in patients with type 2 diabetes mellitus and cardiac autonomic neuropathy

Aim. To assess arterial wall stiffness, plasma levels of of N-terminal prohormone of brain natriuretic peptide (NT-proBNP), as well as functional state and structure of the myocardium in patients with type 2 diabetes mellitus (T2DM) and cardiac autonomic neuropathy (CAN). Materials and Methods. The study involved a total of 65 patients with T2DM. 12 had no evidence of cardiovascular disease (CVD) or CAN, 14 were diagnosed with subclinical stage of CAN, 18 ? with functional stage, and 21 ? with organic stage. We measured aortic pulse wave velocity (PWV), aortic augmentation index (AIx), brachial artery AIx, ambulatory arterial stiffness index (AASI) and plasma levels of NT-proBNP. Clinical examination included ECG, Holter monitoring, ambulatory BP measurement and echocardiography. Results.  Patients with isolated T2DM showed a trend for increased vascular wall stiffness. PWV was increased in patients with subclinical stage of CAN. Aortic and brachial AIx, PWV and AASI were elevated in patients with functional stage of CAN, PWV being significantly higher vs. subclinical CAN subgroup. Organic stage was characterized by pathologically increased values of all primary parameters; PWV and AASI were significantly higher compared with other groups. Development and progression of CAN was accompanied by an increase in NT-proBNP plasma levels. Concentration of NT-proBNP was in direct correlation with left ventricular mass (LVM) and PWV. PWV and LVM values also directly correlated between themselves. Conclusion. Development and progression of CAN in patients with T2DM is accompanied by an increase in vascular wall stiffness. The elevation of plasma NT-proBNP in patients with T2DM correlates with the development of CAN and is significantly and independently associated with an increase in LVM and PWV. Our data suggests the pathophysiological interconnection between metabolic, functional and structural myocardial abnormalities in patients with T2DM and CAN.

Arterial stiffness, fatty liver and the presence of coronary artery calcium in a large population cohort

BACKGROUND

We tested whether fatty liver, brachial-ankle pulse wave velocity (baPWV) and conventional cardiovascular risk factors were associated with a coronary artery calcium (CAC) score > 0 (as a marker of the presence of early atherosclerosis) in a cohort of healthy Korean adults.

METHOD

The study population consisted of individuals who underwent a comprehensive health examination in 2010 at Kangbuk Samsung Hospital, College of Medicine, Sungkyunkwan University in South Korea. The 6009 subjects of total 7371 participants who had an assigned CAC score following coronary computed tomography (CT) scanning and baPWV were analyzed.

RESULTS

Among the study subjects, 39.2% of the population had evidence of fatty liver by ultrasound and 4.6% of the population had evidence of CAC score > 0. Among individuals with a CAC score = 0, 38% of the individuals had fatty liver compared with 58% of the individuals with a CAC score > 0. The individuals with a CAC score > 0 also had higher blood pressure and had more metabolic abnormalities. The prevalence of CAC score > 0 was increased according to baPWV quartiles and was higher in the fatty liver group in comparison with those without fatty liver. The odds ratio for CAC score > 0, after adjusting for clinical risk factors, showed a significant elevation with increasing quartiles of baPWV and the presence of fatty liver.

CONCLUSION

We showed that both fatty liver and baPWV are independently associated with the presence of CAC, a marker of preclinical atherosclerosis. These associations are independent of conventional risk factors and medical history.

Central hemodynamic modifications in diabetes mellitus

Arterial stiffness in hypertension is markedly influenced by age, mean arterial pressure (MAP) and heart rate, whereas factors influencing this parameter in diabetes mellitus are not yet fully understood. The aim of our study was to compare central hemodynamics in diabetics (n = 126) versus non-diabetic controls (n = 203), most of whom were hypertensive, and with similar MAP. Anthropometric, laboratory and clinical measurements were collected. Hemodynamic parameters (central blood pressure, aortic pulse wave velocity [PWV], augmentation index [AIx] and pulse pressure amplification [PPA]) were measured using applanation tonometry. PWV and AIx were significantly higher in diabetics, after adjustment for age, gender, MAP, and heart rate. After further adjustment for metabolic syndrome, only the difference in PWV persisted (P < 0.0001). PPA was marginally altered though not significantly. In diabetics, PWV did not correlate with MAP, suggesting that other structural alterations, resulting from insulin resistance, may account for diabetic arterial stiffening to a greater extent than, and independently of, blood pressure. Chronic treatment with insulin was associated with increased PWV, independently of blood pressure, diabetes control and duration, or other common confounding variables. In conclusion, hypertensive diabetics had greater arterial stiffness than hypertensive controls. In diabetes, multiple factors affect arterial stiffening independently of hemodynamic status. Notably, insulin therapy (IT) is associated with more severe arterial stiffness, suggesting a consistent relationship between these parameters. It remains to be determined whether IT should be considered as a marker of diabetes severity that leads to increased arterial stiffness, or whether it has a direct/indirect effect on arterial wall modifications.

Association of automated carotid IMT measurement and HbA1c in Japanese patients with coronary artery disease

AIMS

The purpose of this study was to evaluate whether carotid IMT (cIMT) identified using automated software is associated with HbA1c in Japanese patients with coronary artery disease.

METHODS

370 consecutive patients (males 218; median age 69 years ± 11) who underwent carotid-US and first coronary angiography were prospectively analyzed. After ultrasonographic examinations were performed, the plaque score (PS) was calculated and automated IMT analysis was obtained with a dedicated algorithm. Pearson correlation analysis was performed to calculate the association between automated IMT, PS and HbA1c.

RESULTS

The mean value of cIMT was 1.00 ± 0.47 mm for the right carotid and 1.04 ± 0.49 mm for the left carotid; the average bilateral value was 1.02 ± 0.43 mm. No significant difference of cIMT was detected between men and women. We found a direct correlation between cIMT values and HbA1c (p=0.0007) whereas the plaque score did not correlate with the HbA1c values (p>0.05) CONCLUSION: The results of our study confirm that automated cIMT values and levels of HbA1c in Japanese patients with coronary artery disease are correlated whereas the plaque score does not show a statistically significant correlation.

Vascular function and atherosclerosis progression after 1 y of flavonoid intake in statin-treated postmenopausal women with type 2 diabetes: a double-blind randomized controlled trial

BACKGROUND

In healthy participants, short-term flavan-3-ol and isoflavone intakes improve vascular function; however, the potential combined benefit of these compounds on atherosclerosis progression remains unclear for those at elevated risk of cardiovascular disease.

OBJECTIVE

The objective was to examine whether combined isoflavone and flavan-3-ol intake alters vascular function in postmenopausal women with type 2 diabetes mellitus (T2DM).

DESIGN

A double-blind, parallel-design, placebo-controlled 1-y trial was conducted in postmenopausal T2DM patients randomly assigned to a split dose of 27 g flavonoid-enriched chocolate/d [850 mg flavan-3-ols (90 mg epicatechin) + 100 mg isoflavones (aglycone equivalents)/d] or matched placebo. Intima-media thickness of the common carotid artery (CCA-IMT), pulse wave velocity (PWV), augmentation index, blood pressure (BP), and vascular biomarkers were assessed.

RESULTS

A total of 93 patients completed the trial. Overall, the flavonoid intervention did not significantly change CCA-IMT, augmentation index, or BP, but pulse pressure variability improved (flavonoid: -0.11 ± 0.07 mm Hg/min; placebo: 0.10 ± 0.11 mm Hg/min; P = 0.04). In a subgroup with PWV data, net improvements were observed [flavonoid (n = 18): -0.07 ± 0.38 m/s; placebo (n = 17): 0.68 ± 0.25 m/s; P = 0.01], which equated to a 10% CV risk reduction. Equol producers (n = 17) had larger reductions in diastolic BP, mean arterial pressure, and PWV (-2.24 ± 1.31 mm Hg, -1.24 ± 1.30 mm Hg, and -0.68 ± 0.40 m/s, respectively; P < 0.01) compared with non-equol producers (n = 30).

CONCLUSIONS

Although the 1-y intervention did not change CCA-IMT or BP, clinically relevant improvements in arterial stiffness were observed; equol producers were particularly responsive. Flavonoids may augment existing therapeutic strategies to reduce cardiovascular disease risk in postmenopausal T2DM patients, and longer studies are needed to examine the effects on atherosclerosis progression. This trial was registered at clinicaltrials.gov as NCT00677599.

Effects of weight loss and insulin reduction on arterial stiffness in the SAVE trial

Background

Chronic arterial stiffness contributes to the negative health effects of obesity and insulin resistance, which include hypertension, stroke, and increased cardiovascular and all-cause mortality. Weight loss and improved insulin sensitivity are individually associated with improved central arterial stiffness; however, their combined effects on arterial stiffness are poorly understood. The purpose of this study was to determine how insulin levels modify the improvements in arterial stiffness seen with weight loss in overweight and obese young adults.

Methods

To assess the effects of weight loss and decreased fasting insulin on vascular stiffness, we studied 339 participants in the Slow the Adverse Effects of Vascular Aging (SAVE) trial. At study entry, the participants were aged 20–45, normotensive, non-diabetic, and had a body-mass index of 25–39.9 kg/m². Measures of pulse wave velocity (PWV) in the central (carotid-femoral (cfPWV)), peripheral (femoral-ankle (faPWV)), and mixed (brachial-ankle (baPWV)) vascular beds were collected at baseline and 6 months. The effects of 6-month change in weight and insulin on measures of PWV were estimated using multivariate regression.

Results

After adjustment for baseline risk factors and change in systolic blood pressure, 6-month weight loss and 6-month change in fasting insulin independently predicted improvement in baPWV but not faPWV or cfPWV. There was a significant interaction between 6-month weight change and change in fasting insulin when predicting changes in baPWV (p < 0.001). Individuals experiencing both weight loss and insulin reductions showed the greatest improvement in baPWV.

Conclusions

Young adults with excess weight who both lower their insulin levels and lose weight see the greatest improvement in vascular stiffness. This improvement in vascular stiffness with weight loss and insulin declines may occur throughout the vasculature and may not be limited to individual vascular beds.

Trial registration

NCT00366990

Effect of vitamin D on aortic remodeling in streptozotocin-induced diabetes

BACKGROUND

Diabetes mellitus is associated with micro- and macrovascular complications and increased cardiovascular risk. Elevated levels of serum asymmetric dimethylarginine (ADMA) may be responsible for endothelial dysfunction associated with diabetes-induced vascular impairment. Vitamin D may have potential protective effects against arterial stiffening. This study aimed to examine both the effects of diabetes on the functional/structural properties of the aorta and the endothelial function and the effects of vitamin D supplementation.

METHODS

Male Wistar rats (n = 30) were randomly assigned to control untreated, diabetic untreated, and diabetic + cholecalciferol groups. Diabetes was induced by intraperitoneal injection of streptozotocin, followed by oral administration of cholecalciferol (500 IU/kg) for 10 weeks in the treatment group. Aortic pulse wave velocity (PWV) was recorded over a mean arterial pressure (MAP) range of 50 to 200 mmHg using a dual pressure sensor catheter. Intravenous infusion of phenylephrine and nitroglycerine was used to increase and decrease MAP, respectively. Serum 25-hydroxyvitamin D [25(OH)D] levels were measured using a radioimmune assay. ADMA levels in serum were measured by enzyme-linked immunoassay. Aortic samples were collected for histomorphometrical analysis.

RESULTS

PWV up to MAP 170 mmHg did not reveal any significant differences between all groups, but in diabetic rats, PWV was significantly elevated across MAP range between 170 and 200 mmHg. Isobaric PWV was similar between the treated and untreated diabetic groups, despite significant differences in the levels of serum 25(OH)D (493 ± 125 nmol/L vs 108 ± 38 nmol/L, respectively). Serum levels of ADMA were similarly increased in the treated and untreated diabetic groups, compared to the control group. The concentration and integrity of the elastic lamellae in the medial layer of the aorta was impaired in untreated diabetic rats and improved by vitamin D supplementation.

CONCLUSION

PWV profile determined under isobaric conditions demonstrated differential effects of uncontrolled diabetes on aortic stiffness. Diabetes was also associated with elevated serum levels of ADMA. Vitamin D supplementation did not improve the functional indices of aortic stiffness or endothelial function, but prevented the fragmentation of elastic fibers in the aortic media.

Using the spring constant method to analyze arterial elasticity in type 2 diabetic patients

BACKGROUND

This study tests the validity of a newly-proposed spring constant method to analyze arterial elasticity in type 2 diabetic patients.

METHODS

The experimental group comprised 66 participants (36 men and 30 women) ranging between 46 and 86 years of age, all with diabetes mellitus. In the experimental group, 21 participants suffered from atherosclerosis. All were subjected to the measurements of both the carotid-femoral pulse wave velocity (cfPWV) and the spring constant method. The comparison (control) group comprised 66 normal participants (37 men and 29 women) with an age range of 40 to 80 years who did not have diabetes mellitus. All control group members were subjected to measurement by the spring constant method.

RESULTS

Statistical analysis of the experimental and control groups indicated a significant negative correlation between the spring constant and the cfPWV (P < .001; r = - 0.824 and - 0.71). Multivariate analysis similarly indicated a close relationship. The Student's t test was used to examine the difference in the spring constant parameter between the experimental and control groups. A P-value less than .05 confirmed that the difference between the 2 groups was statistically significant. In receiver operating characteristic curve (ROC), the Area Under Curve (AUC, = 0.85) indicates good discrimination. These findings imply that the spring constant method can effectively identify normal versus abnormal characteristics of elasticity in normal and diabetic participants.

CONCLUSIONS

This study verifies the use of the spring constant method to assess arterial elasticity, and found it to be efficient and simple to use. The spring constant method should prove useful not only for improving clinical diagnoses, but also for screening diabetic patients who display early evidence of vascular disease.

Insulin resistance increases the occurrence of new cardiovascular events in patients with manifest arterial disease without known diabetes. the SMART study

Background

Insulin resistance is accompanied by a cluster of metabolic changes, often referred to as metabolic syndrome. Metabolic syndrome is associated with an increased cardiovascular risk in patients with manifest arterial disease. We investigated whether insulin resistance is associated with an increased risk for cardiovascular events in patients with manifest arterial disease without known diabetes and whether this can be explained by the components of the metabolic syndrome or by inflammation.

Methods

Prospective cohort study in 2611 patients with manifest arterial disease without known diabetes. Homeostasis model of insulin resistance (HOMA-IR) was used to quantify insulin resistance. The relation of HOMA-IR with cardiovascular events (vascular death, myocardial infarction or stroke) and all cause mortality was assessed with Cox regression analysis. In additional models adjustments were performed for the single components constituting the metabolic syndrome and for inflammation.

Results

HOMA-IR increases with the number of metabolic syndrome components (mean HOMA-IR ± SD in groups with 0, 1, 2, 3, 4 and 5 metabolic syndrome components: 1.4 ± 0.7; 1.8 ± 1.2; 2.4 ± 1.5; 3.1 ± 1.8; 4.0 ± 2.6; and 5.6 ± 3.6 respectively). High HOMA-IR was independently associated with an increased risk of cardiovascular events (tertile 2 vs. 1 HR 1.92; 95%CI 1.20-3.08) (tertile 3 vs.1 HR 1.78; 95%CI 1.10-2.89) and with all cause mortality (tertile 2 vs. 1 HR 1.80; 95%CI 1.04-3.10) (tertile 3 vs.1 HR 1.56; 95%CI 0.88-2.75). These relations were not influenced by the individual components of metabolic syndrome or by inflammation.

Conclusions

In patients with manifest arterial disease without known diabetes, insulin resistance increases with the number of metabolic syndrome components, and elevated insulin resistance increases the risk of new cardiovascular events.

Arterial pulse wave velocity in relation to carotid intima-media thickness, brachial flow-mediated dilation and carotid artery distensibility: the Cardiovascular Risk in Young Finns Study and the Health 2000 Survey

OBJECTIVE

Increased arterial pulse wave velocity (PWV) is a strong predictor of cardiovascular events and mortality. The data regarding the relationships between PWV and other indices of vascular damage is limited and partly controversial. We conducted the present study to examine PWV in relation to non-invasive measures of early atherosclerosis (brachial flow-mediated dilation [FMD], carotid intima-media thickness [IMT]) and local arterial stiffness (carotid artery distensibility [Cdist]).

METHODS

The study population consisted of 1754 young adults (aged 30-45 years, 45.5% males) participating in the Cardiovascular Risk in Young Finns Study (YFS), and of 336 older adults (aged 46-76 years, 43.2% males) participating in the Health 2000 Survey. FMD was measured only in the YFS cohort. FMD, IMT and Cdist were assessed by ultrasound, and PWV was measured using the whole-body impedance cardiography device.

RESULTS

In young adults, FMD and IMT were not associated with PWV independently of cardiovascular risk factors. Moreover, FMD status was not found to modulate the association between cardiovascular risk factors and PWV. In older adults, PWV and IMT were directly and independently associated (β=1.233, p=0.019). In both cohorts, PWV was inversely related with Cdist, and this relation remained significant (p<0.04) in models adjusted for cardiovascular risk factors.

CONCLUSIONS

The current findings suggest that PWV reflects a different aspect of vascular damage than FMD or IMT in young adults, whereas in older adults the information provided by PWV and IMT may be, to some extent, similar as regards subclinical vascular damage. The present observations also suggest that PWV and Cdist represent, at least in part, a similar adverse vascular wall process.

Relationship between pulse wave velocity and carotid atherosclerosis in geriatric people

OBJECTIVE

To investigate the relationship between the pulse wave velocity (PWV) and angiographic carotid atherosclerosis in elderly patients.

METHOD

103 consecutive elderly patients were divided into two groups according to the results of cerebral angiography: carotid atherosclerosis group and normal carotid angiogram group. Basic clinical information was required by a standardized questionnaire. Carotid-femoral PWV (cfPWV) as a marker of Stiffness of artery was measured, Carotid intima media thickness (IMT) and carotid stenosis degree in angiography was evaluated. Independent-sample t test was used to evaluate the difference in cfPWV between the two groups, Bivariate associations between cfPWV and an index of extracoronary atherosclerosis (IMT and severity of stenosis) was performed.

RESULT

Among 103 subjects, 55 with carotid atherosclerosis and 48 with a normal carotid angiogram, a significant difference between the two groups in IMT and PWV was found (P<0.05), and the cfPWV was significantly correlated with IMT (r = 0.3222, P = 0.0315), but not severity of carotid stenosis (r = 0.1573, P = 0.3137).

CONCLUSION

cfPWV showed a positive correlation to carotid IMT, and maybe is a potentially useful adjunctive atherosclerotic risk marker to Identify of early carotid atherosclerosis.