Increased carotid IMT in patients with type 2 diabetes free of cardiovascular complications appears to be an adaptive mechanism to an increased wall stress more than atheromasic degeneration

Type 2 diabetes (DM2) and poor glycemic control adversely affect common carotid intima media thickness (IMT), considered marker of preclinical atherosclerosis. However, studies evaluating the effect of DM2 and glucose levels on IMT did not consider carotid diameter, known to affect IMT. A certain IMT increase could reflect a mutual adjustment between diameter and wall thickness aimed to maintain constant wall tensile stress (WTS). Aim: To compare carotid IMT, luminal diameter, WTS and local wave speed (WS) between patients with uncomplicated DM2 and healthy controls. Methods: Eighty-four patients with well controlled DM2 (HbA1c <7.8%) and 84 controls matched for sex, age and BMI. were studied by radiofrequencybased carotid ultrasound (QIMT and QAS, Esaote). Results: DM2 against controls had higher (p<0.0001) IMT (720131 vs. 62076 mm), luminal diameter (6.60.6 vs. 6.00.7 mm), WS (8.3.61.7 vs. 6.51.2 m/s) and pulse pressure (5813 vs. 478 mmHg), but comparable WTS (498 vs. 5014 kPa; pZ0.82). In the entire population, fasting glucose was not independently related to IMT, but was related to carotid diameter (together with male sex and waist), pulse pressure and local WS (together with age and antihypertensive treatment). In DM2, HbA1c was independently related to carotid diameter, pulse pressure and WS. Conclusions: Chronically increased plasma glucose levels may induce intrinsic stiffening of large artery and widening of pulse pressure. Increased pulsatile load in stiff arteries causes luminal dilatation and increases WTS, triggering an increase in arterial wall thickness. Hyperglycaemia affects arterial wall, but through a “sclerotic” more than “atherogenic” mechanism

Impact of glycemic control on aortic stiffness, left ventricular mass and diastolic longitudinal function in type 2 diabetes mellitus

Poor glycemic control is associated with impaired left ventricular (LV) diastolic function in patients with type 2 diabetes mellitus (T2DM). Inappropriate LV mass increase and accelerated aortic stiffening were suggested to participate on deterioration of diastolic function. The present study investigated the inter-relationships between glycemic control, early diastolic and systolic longitudinal velocity of mitral annulus, LV mass and aortic stiffness in T2DM patients free of cardiovascular disease and with preserved LV ejection fraction, and compared them with those observed in healthy volunteers of similar age and sex distribution

Hypnotizability-related complexity of heart rate variability during long lasting relaxation

Aim of the experiment was to compare heart rate and HRV of healthy subjects with high (Highs) and low (Lows) susceptibility to hypnosis during long-lasting relaxation. HRV indexes extracted in the frequency and time domain as well as related to the complexity of the tachogram (entropy) were analyzed through repeated measures ANOVA. The results indicated a parasympathetic prevalence in Highs all over the session and a sympathetic modulation across the session in both groups reflected in the sd2 dimension of the Poincar? plot and in entropy. The possible role of the Very Low Frequency spectral component in these changes, supported by the different correlations between entropy and frequency/time related indexes of HRV, is suggeste

P24 Restored Physiological Local Carotid Pulse Wave Velocity After Bariatric Surgery in Obese Subjects

AbstractObesity is a risk factor for cardiovascular events and is associated with increased arterial stiffness [1,2]. However, the effect of drastic changes in Body Mass Index (BMI) on arterial mechanics has not been fully investigated. Our study aimed at evaluating changes in local carotid PWV (cPWV) in obese patients before and 6 months after bariatric surgery. N = 20 obese subjects free of cardiovascular events and diabetes (44 ± 9 years, 5 men, BMI = 48.8 ± 7.5 kg/m2) undergoing bariatric surgery were recruited in the Pisa University Hospital (Italy). Flow and diameter waveforms were acquired by ultrasound scanner (Aloka Alpha10, Hitachi Group, Japan) (1 kHz) at the right common carotid artery at baseline, after a 32.4 ± 7.6 days diet period, and 6.5 ± 2.7 months post-intervention. The lnDU-loop method was used for the estimation of cPWV [3]. Basal cPWV was 6.05 ± 1.21 m/s. The 1-month diet period produced a 2 kg/m2 reduction in BMI, while cPWV decreased by approx. 0.6 m/s. 6–7 months after bariatric surgery, BMI dropped to 35.3 ± 6.5 kg/m2 and cPWV furtherly decreased of approx. 0.9 m/s reaching a mean value of 4.57 ± 1.02 m/s (76% of the basal value) (Figure 1). Bariatric surgery and the consequent intensive weight loss produced a significant decrease of arterial stiffness and restored cPWV to physiological values of age-matched healthy subjects [4]. The fast reversal of increased arterial stiffness suggests a functional mechanism possibly related to a reduced haemodynamic load. Moreover, while having a small effect on the BMI, 1-month diet regulation effectively decreased cPWV by 10%, possibly indicating the short-term positive effects of a healthy lifestyle on haemodynamics

Large Artery Remodeling and Dynamics following Simulated Microgravity by Prolonged Head-Down Tilt Bed Rest in Humans

The effects of simulated microgravity on the static and dynamic properties of large arteries are still mostly unknown. The present study evaluated, using an integrated vascular approach, changes in structure and function of the common carotid and femoral arteries (CCA and CFA) after prolonged head-down tilt bed rest (HDTBR). Ten healthy men were enrolled in a 5-week HDTBR study endorsed by the Italian Space Agency (ASI). Arterial geometry, flow, stiffness, and shear rate were evaluated by ultrasound. Local carotid pulse pressure and wave reflection were studied by applanation tonometry. After five weeks of HDTBR, CFA showed a decrease in lumen diameter without significant changes in wall thickness (IMT), resulting in an inward remodeling. Local carotid pulse pressure decreased and carotid-to-brachial pressure amplification increased. The ratio of systolic-to-diastolic volumetric flow in CFA decreased, whereas in CCA it tended to increase. Indices of arterial stiffness and shear rate did not change during HDTBR, either in CCA or CFA. In summary, prolonged HDTBR has a different impact on CCA and CFA structure and flow, probably depending on the characteristics of the vascular bed perfuse

Carotid Reservoir Pressure Decrease After Prolonged Head Down Tilt Bed Rest in Young Healthy Subjects Is Associated With Reduction in Left Ventricular Ejection Time and Diastolic Length

BACKGROUND: The arterial pressure waveform reflects the interaction between the heart and the arterial system and carries potentially relevant information about circulatory status. According to the commonly accepted ‘wave transmission model’, the net BP waveform results from the super-position of discrete forward and backward pressure waves, with the forward wave in systole determined mainly by the left ventricular (LV) ejection function and the backward by the wave reflection from the periphery, the timing and amplitude of which depend on arterial stiffness, the wave propagation speed and the extent of downstream admittance mismatching. However, this approach obscures the ‘Windkessel function’ of the elastic arteries. Recently, a ‘reservoir-excess pressure’ model has been proposed, which interprets the arterial BP waveform as a composite of a volume-related ‘reservoir’ pressure and a wave-related ‘excess’ pressure. METHODS: In this study we applied the reservoir-excess pressure approach to the analysis of carotid arterial pressure waveforms (applanation tonometry) in 10 young healthy volunteers before and after a 5-week head down tilt bed rest which induced a significant reduction in stroke volume (SV), end-diastolic LV volume and LV longitudinal function without significant changes in central blood pressure, cardiac output, total peripheral resistance and aortic stiffness. Forward and backward pressure components were also determined by wave separation analysis. RESULTS: Compared to the baseline state, bed rest induced a significant reduction in LV ejection time (LVET), diastolic time (DT), backward pressure amplitude (bP) and pressure reservoir integral (INTPR). INTPR correlated directly with LVET, DT, time to the peak of backward wave (bT) and stroke volume, while excess pressure integral (INTXSP) correlated directly with central pressure. Furthermore, Δ.INTPR correlated directly with Δ.LVET, and Δ.DT, and in multivariate analysis INTPR was independently related to LVET and DT and INTXSP to central systolic BP. CONCLUSION: This is an hypothesis generating paper which adds support to the idea that the reservoir-wave hypothesis applied to non-invasively obtained carotid pressure waveforms is of potential clinical usefulness

Large Artery Remodeling and Dynamics following Simulated Microgravity by Prolonged Head-Down Tilt Bed Rest in Humans

The effects of simulated microgravity on the static and dynamic properties of large arteries are still mostly unknown. The present study evaluated, using an integrated vascular approach, changes in structure and function of the common carotid and femoral arteries (CCA and CFA) after prolonged head-down tilt bed rest (HDTBR). Ten healthy men were enrolled in a 5-week HDTBR study endorsed by the Italian Space Agency (ASI). Arterial geometry, flow, stiffness, and shear rate were evaluated by ultrasound. Local carotid pulse pressure and wave reflection were studied by applanation tonometry. After five weeks of HDTBR, CFA showed a decrease in lumen diameter without significant changes in wall thickness (IMT), resulting in an inward remodeling. Local carotid pulse pressure decreased and carotid-to-brachial pressure amplification increased. The ratio of systolic-to-diastolic volumetric flow in CFA decreased, whereas in CCA it tended to increase. Indices of arterial stiffness and shear rate did not change during HDTBR, either in CCA or CFA. In summary, prolonged HDTBR has a different impact on CCA and CFA structure and flow, probably depending on the characteristics of the vascular bed perfused

Circulating endothelial progenitor cells and large artery structure and function in young subjects with uncomplicated Type 1 Diabetes

<p>Abstract</p> <p>Background</p> <p>Carotid intima-media thickness (IMT), indices of large artery stiffness and measures of endothelium function may be used as markers of early atherosclerosis in type 1 diabetes mellitus (T1DM). The aim of the present study was to compare the indices of large artery structure and function as well as endothelial function and regenerating capacity between adolescents with T1DM and healthy control of similar age. In addition, the associations of different vascular measures with endothelial progenitor cells (EPCs), glyco-metabolic control and serum levels of advanced glycation endproducts (AGEs), soluble receptors for AGEs (sRAGE) and adiponectin were evaluated.</p> <p>Methods</p> <p>Sixteen uncomplicated young T1DM patients (mean age 18 ± 2 years, history of disease 11 ± 5 years, HbA1c 7.7 ± 1.1%) and 26 controls (mean age 19 ± 2 years) were studied. A radiofrequency-based ultrasound system (Esaote MyLab 70) was used to measure carotid IMT and wave speed (WS, index of local stiffness), applanation tonometry (PulsePen) was applied to obtain central pulse pressure (PP) and augmentation index (AIx), and carotid-femoral pulse wave velocity (PWV, Complior) was used as index of aortic stiffness. Peripheral endothelium-dependent vasodilation was determined as reactive hyperemia index (RHI, EndoPAT). Circulating EPCs, glycometabolic profile, AGEs (autofluorescence method), sRAGE and adiponectin were also measured.</p> <p>Results</p> <p>After adjusting for age, sex and blood pressure, T1DM adolescents had significantly higher carotid IMT (456 ± 7 vs. 395 ± 63 μm, p < 0.005), carotid WS (p < 0.005), PWV (p = 0.01), AIx (p < 0.0001) and central PP (p < 0.01) and lower EPCs (p = 0.02) as compared to controls. RHI was reduced only in diabetic patients with HbA1c ≥7.5% (p < 0.05). In the overall population, EPCs were an independent determinant of carotid IMT (together with adiponectin), while fasting plasma glucose was an independent determinant of carotid WS, AIx and central PP.</p> <p>Conclusions</p> <p>Our findings suggest that young subjects with relatively long-lasting T1DM have a generalized preclinical involvement of large artery structure and function, as well as a blunted endothelium regenerating capacity. Hyperglycemia and suboptimal chronic glycemic control seem to deteriorate the functional arterial characteristics, such as large arteries stiffness, wave reflection and peripheral endothelium-dependent vasodilation, whereas an impaired endothelium regenerating capacity and adiponectin levels seem to influence arterial structure.</p

Relationship of different cardiovascular tissue biomarkers with established risk factors and framingham risk score in middle-age subjects without cardiovascular events

This abstracts investigates the relationship of different cardiovascular tissue biomarkers with established risk factors and framingham risk score in middle-age subjects without cardiovascular event