Carotid Artery Elasticity Research Articles

Carotid artery intima-media thickness and elasticity in relation to glucose tolerance

The association between diabetes and subclinical atherosclerosis is well established. The effect of non-diabetic glucose intolerance on early atherosclerosis is not as straightforward, and the data regarding sex-related differences in this matter are limited. Therefore, our aim was to investigate these associations in men and women separately. We studied 1,304 Finnish men and women over 45 years of age who participated in the Finnish Health 2000 Survey. Ultrasonically determined carotid artery intima-media thickness and elasticity were used as markers of early atherosclerosis. Glucose tolerance was categorized according to the American Diabetes Association criteria for diabetes mellitus. Age-adjusted means for carotid artery intima-media thickness and elasticity indices were significantly (P < 0.05) associated with glucose tolerance status in both sexes. There was a trend of increasing early atherosclerosis with the worsening of glucose tolerance in men and women. These associations were weakened in both sexes after further adjustments for other cardiovascular risk factors. In women, but not in men, significant (P < 0.05) associations between glucose tolerance status and carotid artery elasticity were seen even after these further adjustments. Diabetes and non-diabetic glucose intolerance are associated with increased early carotid atherosclerosis compared with normal glucose tolerance in both sexes. Our results suggest that women with glucose intolerance may be in greater risk than men.

Evaluation of intima-media thickness and vascular elasticity of the common carotid artery in patients with isolated systolic hypertension using ultrasound radiofrequency-data technology

Radiofrequency (RF) data technology is a newly developed method to evaluate vascular disease, especially subclinical atherosclerotic change. Data regarding predictors of intima-media thickness (IMT) and vascular elasticity of the common carotid artery (CCA) in subjects with isolated systolic hypertension (ISH) using ultrasound RF-data technology are scarce. We evaluated the change in IMT and vascular elasticity of the CCA in patients with ISH at an early phase using US RF-data technology. Thirty-nine patients with ISH and 41 age-matched control subjects were the study population. The common carotid arterial systolic diameter (Ds), diastolic diameter (Dd), IMT, carotid distensibility (CD), local pulse wave velocity (PWVβ) and stiffness (β) were compared between the two groups, as were correlations between pulse pressure (PP) and parameters of vascular stiffness. Common carotid arterial Ds, Dd, IMT, PWVβ and β increased whereas CD decreased more significantly in the ISH group than in age-matched controls. The level of PP in the ISH group had significant positive correlations with PWVβ (r = 0·298, P<0·05) and β (r = 0·291, P<0·05), whereas significant correlations with CD were not observed. US RF-data technology could be used to accurately and quantitatively evaluate increased IMT and decreased arterial elasticity of the CCA in patients with ISH compared with normal subjects.

Polymorphism in the C-reactive protein (CRP) gene affects CRP levels in plasma and one early marker of atherosclerosis in men: The Health 2000 Survey

Background. C-reactive protein (CRP) is an inflammatory protein that may play a role in the pathogenesis of cardiovascular disease (CVD). However, its status as a causal risk factor is still controversial. CRP gene single nucleotide polymorphisms (SNPs) have been shown to associate with CRP concentration, but not convincingly with early atherosclerotic changes. Objective. We assessed whether CRP genotypes or their haplotypes associate with plasma CRP levels or carotid artery intima-media thickness (IMT) or carotid artery elasticity (CAE) in a Finnish middle-aged study population. Methods. We genotyped CRP gene polymorphisms −717A>G (rs2794521), −286C>T>A (rs3091244), +1059G>C (rs1800947), +1444C>T (rs1130864) and +1846G>A (rs1205) and measured CRP concentration in a sub-population (N=1332, mean age 58.2 ± 8.0, women n=727 and men n=605) of a large Finnish cross-sectional health examination survey, The Health 2000 Study, carried out in 2000–2001. Results. Significant association (both sexes p<0.0001, women p=0.015 and men p=0.029) was found between CRP rs1800947 genotype and CRP concentration. Multivariate analysis showed an independent effect of the genotype on CRP concentration after adjustment for risk factors (women p=0.036 and men p=0.009). Similar associations were seen at the haplotype level in haplotype ACCCA where +1059 C-carriers had lower median CRP values than non-carriers (p=0.008). One CRP genotype (rs1130864) was associated with one CAE parameter in men but no association was observed between CRP genotypes and carotid artery IMT. Conclusions. CRP gene allelic variation is associated with CRP levels in both sexes and with one CAE parameter (SI) in men in a population-based Finnish cohort of middle-aged subjects.

Impaired carotid artery elastic function in patients with tetralogy of Fallot

Complex congenital heart diseases with abnormal formation of the aorticopulmonary septum are also associated with defective large artery elastogenesis. In the current study, we tested the hypothesis that carotid artery elastic function was impaired in patients with tetralogy of Fallot (ToF). The study included 45 Fallot-patients (male:female 27:18; age 21.0±11.8years) and 45 age- and gender-matched healthy control individuals. Carotid artery diameter, pulsatile distension, and intima-media thickness (IMT) were measured by echotracking device, and carotid blood pressure was determined using applanation tonometry. Carotid artery elasticity was characterized by compliance and distensibility coefficients, stiffness index β, and incremental elastic modulus. All carotid artery elastic parameters showed significant differences between groups. The compliance coefficient was 36%, and the distensibility coefficient was 33% smaller, whereas stiffness index β was 46% and incremental elastic modulus was 40% larger in Fallot-patients. Fallot-patients also had larger carotid artery IMT as compared to that of healthy individuals. Carotid artery is markedly stiffer in Fallot-patients suggesting that impaired elastogenesis is a component of the congenital abnormality. Increased large artery stiffness might contribute directly and indirectly (through impairment of baroreflex function) to the higher mortality found in ToF patients.

Value of the circumferential strain of the blood vessel in estimating the carotid arterial elasticity of the patients with hypertension

Objective To investigate the clinical value of circumferential strain and strain rate in estimating the carotid elasticity. Methods Thirty-five consecutive patients of hypertension were enrolled in this study as the patient group and 36 healthy volunteers whose ages were matched with the patient group were included as controls. The intima-media thickness(IMT) of common carotid arteries of both the patients and controls were measured using RF-Data technique of ultrasound vascular measurement and the following traditional parameters reflecting common carotid elasticity were obtained: pulse wave velocity (PWV),arterial compliance (AC). While the new parameters reflecting vascular strain including endovascular longitudinal strain(EN-LS), endovascular circumferential strain(EN-CS), endovascular longitudinal strain rate(EN-LSR) ,endovascular circumferential strain rate(EN-CSR), adventitial longitudinal strain(EP-LS),adventitial circumferential strain ( EP-CS ), adventitial longitudinal strain rate ( EP-LSR ), adventitial circumferential strain rate(EP-CSR) were collected using the technique of X-strain. All the corresponding parameters were compared between hypertensive group and controls. The correlations between elasticity and hemodynamic parameters were analyzed. Results In the hypertension patients,PWV was higher while AC,EN-CS,EN-CSR,EP-CS and EP-CSR were lower than that of the control group( P ＜0.05). No significant differences were detected in the longitudinal strain and strain rate. In the hypertension group,AC correlated positively with PWV, while EN-CS, EN-CSR, EP-CS and EP-CSR correlated negatively with PWV and positively with AC. Conclusions Circumferential strain and strain rate conform well to the mechanical principle and the characteristic anatomic and histological structure of the vessels and may be used to reflect the early changes of the vascular elasticity. Key words: Ultrasonography; Carotid arteries; Elasticity; Circumferential strain

Adiponectin is related with carotid artery intima-media thickness and brachial flow-mediated dilatation in young adults—The Cardiovascular Risk in Young Finns Study

Aims. Adiponectin may be involved in the pathogenesis of atherosclerosis. We investigated the relation of adiponectin on early functional and structural markers of subclinical atherosclerosis in a large population-based cohort of young men and women.Methods and results. We measured serum adiponectin using radioimmunoassay in 2,147 young adults (ages 24–39 years) participating in the Cardiovascular Risk in Young Finns Study. The subjects had ultrasound data on carotid intima-media thickness (IMT), carotid artery elasticity (n = 2,139) and brachial flow-mediated dilatation (FMD) (n = 1,996). In univariate analysis, adiponectin was inversely associated with IMT (r = −0.16, P < 0.0001) and directly with FMD (r = 0.12, P < 0.0001) and carotid elasticity (r = 0.20, P < 0.0001). The associations for IMT and FMD remained significant in multivariable models adjusted for age, sex, obesity indices, serum lipids, blood pressure, leptin, glucose, and C-reactive protein: IMT (β = −0.018 ± 0.005, P = 0.0002) and FMD (β = 0.72 ± 0.25, P = 0.004). The relation between adiponectin and carotid elasticity attenuated to non-significant after adjusting for waist circumference and systolic blood pressure.Conclusion. In young healthy adults, low serum adiponectin concentration is independently related with increased carotid IMT and attenuated brachial FMD, supporting the role of adiponectin in the pathogenesis of early atherosclerosis.

Quantitative evaluation ofcommon carotid arterial intima-media thickness and elasticity in healthy adults byultrasound radio-frequency data technology

：Objective To evaluatecommon carotid arterial intima-media thickness (IMT) and elasticity using ultrasoundradio-frequency data (RF-data) technology, the normal values of the related parameterswere determined in healthy adults for their potential clinical applications.Methods Onehundred and sixty healthy adults were included and divided into 4 age groups with 20 malesand 20 females in each group.The quantitative parameters of common carotid arterial IMT,common carotid arterial distensibility (CD),local pulse wave velocity(PWVβ) andstiffness(β) were calculated automatically.The correlations that the IMT, PWVβ and β were correlated positivelywith aging and CD was correlated negatively with between IMT and PWVβ or β, while no correlationbetween IMT and CD.The positive correlation was found correlation between IMT and age ( P＜0.05);In 30～39 and 40～49 years old groups,PWVβ increased and CD decreased with aging;In 50～59years old group,PWVβ and β increased with aging;But in 60～69 years these parameterschanged with aging in subjects＜60 years old.Conclusions RF-data technology couldquantitativly evaluate common carotid arterial IMT and elasticity, the normal values ofthe related parameters were determined with aging,it may be a promising modality to assessthe arterial condition. Key words: Ultrasonography ; Carotid artery, common ; Elasticity; Intima-media thickness D0I:10.3760/cma.j.issn.1004-4477.2010.06.017

Early Signs of Atherosclerosis in Diabetic Children on Intensive Insulin Treatment

OBJECTIVETo evaluate early stages of atherosclerosis and predisposing factors in type 1 diabetic children and adolescents compared with age- and sex-matched healthy control subjects.RESEARCH DESIGN AND METHODSAll children and adolescents with type 1 diabetes, aged 8–18 years in Health Region South-East in Norway were invited to participate in the study (n = 800). A total of 40% (n = 314) agreed to participate and were compared with 118 age-matched healthy control subjects. Carotid artery intima-media thickness (cIMT) and elasticity were measured using standardized methods.RESULTSMean age of the diabetic patients was 13.7 years, mean diabetes duration was 5.5 years, and mean A1C was 8.4%; 97% were using intensive insulin treatment, and 60% were using insulin pumps. Diabetic patients had more frequently elevated cIMT than healthy control subjects: 19.5% were above the 90th centile of healthy control subjects, and 13.1% were above the 95th centile (P < 0.001). Mean cIMT was higher in diabetic boys than in healthy control subjects (0.46 ± 0.06 vs. 0.44 ± 0.05 mm, P = 0.04) but not significantly so in girls. There was no significant difference between the groups regarding carotid distensibility, compliance, or wall stress. None of the subjects had atherosclerotic plaque formation. Although within the normal range, the mean values of systolic blood pressure, total cholesterol, LDL cholesterol, and apolipoprotein B were significantly higher in the diabetic patients than in the healthy control subjects.CONCLUSIONSDespite short disease duration, intensive insulin treatment, fair glycemic control, and no signs of microvascular complications, children and adolescents with type 1 diabetes had slightly increased cIMT compared with healthy control subjects, and the differences were more prominent in boys.

The relationship between the carotid artery elasticity function and the vascular stenosis after coronary artery bypass grafting

Objective To evaluate the carotid artery elasticity function and the vascular stenosis after coronary artery bypass grafting (CABG). Methods Ninety-seven patients underwent CABG. The severity of coronary artery stenosis was evaluated by Gensini score after CABG. The β, Ep and AC of the carotid artery elasticity function were measured by B-ultrasound. Results The β (12. 48 ±2. 16) and Ep (140. 41 ± 32. 46) were significantly higher in patients with bypass stenosis coronary artery disease than β (9. 27 ±2. 19) and Ep ( 109. 72 ±31.27) in the normal subjects. The AC (0. 65 ±0. 09) was significantly lower in patients with bypass stenosis coronary artery disease than that (0. 79 ± 0. 11 ) in the normal subjects. Multiple regression analysis indicated the β, Ep and AC of the carotid artery were closely related to the vascular stenosis after CABG. Conclusion The β, Ep and AC of the carotid artery are better predictors for evaluating the vascular stenosis after CABG. Key words: Coronary artery bypass grafting; Artery intima; Carotid artery

The relationship between cerebral artery stenosis and carotid artery elasticity in the ischemia stroke patients by echo-tracking technique

Objective To study the relationship between the cerebral artery stenosis and the carotid artery elasticity in the ischemia stroke patients by echo-tracking technique.Methods Ninety-two ischemia stroke patients were divided into both the mild cerebral arteries stenosis and moderate-severe cerebral arteries stenosis groups.CT angiography was performed to evaluate the stenosis of cerebral artery.The changes of the carotid diameter during cardiac cycles were obtained by echo-tracking technique and the quantitative parameters of pressure-strain elastic modulus (Ep),stiffness (β) and arterial compliance (AC) were calculated automatically. Results ①There were significant differences (P＜0.05) between the ischemia stroke patient group and the normal adults group in β，Ep and AC.② There were significant differences (P＜0.05) between the mild cerebral arteries stenosis groups and the moderate-severe cerebral arteries stenosis groups in β and Ep.AC was lower in patients with the mild cerebral arteries stenosis groups than that in the moderate-severe cerebral arteries stenosis groups.Conclusions The carotid artery elasticity in ischemia stroke patients were significantly different from normal adults.In the ischemia stroke patients,the stiffer the carotid artery was,the higher the likelihood of moderate-severe cerebral stenosis was. Key words: Ultrasonography; Brain infarction; Carotid arteries; Elasticity

Sphygmomanometric and ambulatory blood pressures as forerunners of carotid and femoral intima–media thickness

Studies directly comparing the associations of intima-media thickness with blood pressure (BP) on manual sphygmomanometric blood pressure measurement (SBPM) and 24-h ambulatory blood pressure measurement (ABPM) are scarce and have a cross-sectional design. At baseline, we measured systolic and diastolic blood pressures, pulse pressure, and mean arterial pressure in 532 randomly recruited patients (women, 48.3%; mean age, 38.9 years) by SBPM and ABPM. SBPM was the average of five consecutive readings obtained by trained observers at the patients' homes. We measured carotid intima-media thickness (CIMT) and femoral intima-media thickness (FIMT) by a wall-tracking ultrasound system, 26 months (median) after BP measurement (interquartile range, 21-29 months). We adjusted all analyses for observer, sex, age, BMI, smoking, and total/high-density lipoprotein-cholesterol ratio. The multivariable-adjusted associations of CIMT and FIMT with all BP components on SBPM were not significant (P >or= 0.12). In multivariable-adjusted models, CIMT increased with 24-h systolic blood pressure (effect size per SD increase, +0.131 mm; P = 0.003) and 24-h pulse pressure (+0.139 mm; P = 0.001), whereas FIMT increased with 24-h diastolic blood pressure (+0.091 mm; P = 0.03) and 24-h mean arterial pressure (+0.090 mm; P = 0.04). Models including the ambulatory blood pressure components additionally adjusted for SBPM and more covariables than those listed above were confirmatory. In a general population, BP on ABPM predicts CIMT and FIMT over and beyond highly standardized SBPM. At the elastic carotid artery, CIMT increased predominantly with the pulsatile component of BP, whereas at the muscular femoral artery, FIMT increased with the steady component of BP.

Carotid arterial elasticity is a sensitive atherosclerosis value reflecting visceral fat accumulation in obese subjects

BackgroundWe previously reported the arterial elasticity value we measured to reflect the characteristic features of vessel walls, and to possibly be useful for detecting early stage atherosclerosis in type 2 diabetes. Obesity, especially visceral adiposity, is well known to play a crucial role in the development of metabolic disorders and atherosclerosis. To assess whether arterial elasticity value reflects the effect of obesity on atherosclerosis, we examined the associations of obesity characteristics with atherosclerosis values including arterial elasticity, carotid intima–media thickness (IMT) and pulse wave velocity (PWV). MethodsThree atherosclerosis values were measured in 78 obese subjects (body mass index ≥30). We investigated the associations of atherosclerosis values with obesity-related parameters including abdominal fat accumulation determined by computed tomography. ResultsArterial elasticity values were positively related to established atherosclerosis values, carotid IMT and PWV, in obese subjects. Age, systolic blood pressure and hypertension also correlated with these atherosclerosis values. Single regression analysis showed all three atherosclerosis values to correlate significantly with visceral fat area. Intriguingly, visceral fat area is an independent variable affecting arterial elasticity, but not IMT or PWV. Furthermore, multiple regression analysis revealed that arterial elasticity correlates strongly with visceral fat area. ConclusionsArterial elasticity value we measure is a new parameter for evaluating atherosclerosis in subjects with visceral adiposity and more sensitive than the currently established atherosclerosis values, carotid IMT and PWV. Measuring arterial elasticity has the potential to reveal minute vascular changes, and may have broad clinical applications for evaluating early stage atherosclerosis.

Impact of Lifestyle-Related Diseases on Carotid Arterial Wall Elasticity as Evaluated by an Ultrasonic Phased-Tracking Method in Japanese Subjects

We investigated the relationship between coronary risk factors and the intima-media thickness (IMT) and wall elasticity of carotid arteries. A new real-time ultrasonic measurement system that allows measurement of the elasticity of the carotid arterial intima-media complex was applied to 350 subjects, who were also checked for the presence/absence of hypertension, dyslipidemia, diabetes mellitus and regular smoking. Simultaneous measurement of the elastic modulus and IMT was conducted at four sites in the bilateral carotid arteries. In the group with maximum IMT (max IMT) <1.1 mm, the IMT, as well as the mean elastic modulus in the circumferential direction (Etheta), showed positive correlations with age and coronary risk factors. Multiple regression analysis showed that age, systolic blood pressure and pulse rate remained independent determinants of Etheta. The number of criteria fulfilling the diagnosis of metabolic syndrome showed a good positive correlation with the value of Etheta in the group with max IMT values <1.1 mm. Measurement of carotid arterial wall elasticity together with IMT is useful to detect dis-tortions in intramural elasticity distribution occurring in the early stages of atherosclerosis.

Evaluation of Plaque Stabilization by Fluvastatin with Carotid Intima- Medial Elasticity Measured by a Transcutaneous Ultrasonic-Based Tissue Characterization System

As an approach to tissue characterization, we attempted to classify in vivo carotid plaque tissues in terms of arterial wall elasticity instead of echogenicity on B-mode scanning and investigated whether the effect of fluvastatin on carotid elasticity can be detected in hypercholesterolemic patients. In 170 subjects, simultaneous measurements of intima-media thickness (IMT) and elastic modulus in the circumferential direction (E(theta)) were performed using a new transcutaneous high-resolution Doppler technique. From the observation of various tissues, an elasticity library was obtained as follows: lipid core, 22+/-15 kPa; calcification, 674+/-384 kPa; lipid core- and calcification-free plaques, 173+/-69 kPa; smooth muscle, 104+/-32 kPa; blood clot, 85+/-68 kPa; fibrosis, 273+/-173 kPa.The effect of fluvastatin (30 mg/day, n=62) was assessed over 12 months using the elasticity distribution and serum markers. The statin reduced low-density lipoprotein cholesterol, high-sensitivity CRP, mean IMT and mean E(theta), and increased nitrite/nitrate. In the max IMT > or =1.1 mm group, both E(theta) and IMT decreased significantly. On the other hand, in the max IMT <1.1 mm group, E(theta) but not IMT decreased significantly. The histogram of the subgroups showing increased E(theta) with max IMT> or =1.1 mm revealed a decrease in areas corresponding to E(theta) of 20200 kPa (lipid/smooth muscle-rich tissue) and an increase in relatively hardened areas of <250 kPa (collagen fibers). Non-invasive echographic carotid arterial elasticity measurement is useful for the classification of atherosclerotic plaques and evaluation of chronological and histopathological changes.

Genetics of C-reactive protein and complement factor H have an epistatic effect on carotid artery compliance: The Cardiovascular Risk in Young Finns Study

Atherosclerosis is characterized by a prominent inflammatory component and C-reactive protein (CRP) has been implicated to modulate the complement activity in atherosclerotic arteries via complement factor H (CFH) binding. In this study, we examined whether the gene-gene interactions between CRP haplotypes and CFH Tyr402His functional polymorphism exerted an effect on early atherosclerosis. Single nucleotide polymorphisms (SNPs) in CFH (Tyr402His) and CRP (-717A>G, -286C >T>A, +1059G>C, +1444C>T and +1846G>A) were genotyped in the participants of the Cardiovascular Risk in Young Finns Study (n=1698, aged 24-39 years). The CRP SNPs were further constructed into haplotypes and their interactive effects with the CFH Tyr402His polymorphism on the early atherogenic vascular changes [i.e. carotid artery compliance (CAC) and intima-media thickness (IMT)] were examined. After risk factor adjustment, a significant gene-gene interaction (P=0.007) on CAC was observed between CRP haplotype ATGTG and CFH Tyr402His polymorphism in males. Furthermore, logistic regression analysis verified the risk-modifying interactive effect on CAC between these loci (OR 3.70, 95% CI 1.37-10.02, P=0.010). No effects on CAC were observed in females and no effects on IMT were detected in either sex. We conclude that the combined presence of CRP haplotype ATGTG and CFH 402His allele may be disadvantageous to carotid artery elasticity in males.

Dyslipidemia in Youth with Diabetes: To Treat or Not to Treat?

There are an estimated 1.5 million people with type 1 diabetes (T1D) and 20 million with type 2 diabetes (T2D) in the U.S. today including at least 150 000 younger than 20 years(1). Of concern, both T1D and T2D are increasing in youth and presenting at younger ages(2-4), implying a longer burden of disease and earlier onset of vascular complications(5). Cardiovascular disease (CVD) is the leading cause of death in people with both T1D(6) and T2D(7) and the antecedents of adult CVD are present in children(8-10). Several studies demonstrate tracking of childhood CVD risk factors into adulthood(9-15). Furthermore, CVD risk factors in childhood correlate with abnormalities in surrogate markers of atherosclerosis (such as carotid intima thickness and arterial elasticity)(14;15) and atherosclerotic lesions in pathology evaluations(9;13). Although data indicate that progress has been made reducing microvascular complications in T1D(16;17) and that intensive management with lower HbA1c can reduce CVD events(18), evidence from the Pittsburgh Epidemiology of Diabetes Complications Study suggests a lack of similar progress in reduction of macrovascular as compared with microvascular complications(16). Furthermore, people with both T1D and T2D suffer macrovascular complications and death at earlier ages than non-diabetics(7;19). Importantly, dyslipidemia is a significant CVD risk factor in persons with diabetes(7;20-22) and target low-density lipoprotein cholesterol (LDL) levels continue to be lowered in adults with diabetes (DM)(7). Observational data have emerged recently on prevalence of dyslipidemia in youth with DM(23-26). Yet, despite recent American Diabetes Association (ADA) and American Heart Association (AHA) clinical recommendations on treatment of dyslipidemia in youth with DM(27-30), no treatment data exist in dyslipidemic youth with DM on which to base clinical care. Instead current pediatric recommendations are generated by consensus expert opinion or are extrapolated either from adult data or treatment data on youth with familial hypercholesterolemia(27-31). Given that dyslipidemia is an important and potentially modifiable CVD risk factor, data to inform clinical decision making regarding screening criteria and treatment of dyslipidemia in this high-risk population are of significant public health importance(32). Data from clinical trials in youth with DM are needed to determine the appropriate management strategy. In this article, recent data and current recommendations on dyslipidemia in youth with DM will be reviewed. Evidence supporting the treatment of dyslipidemia in youth with DM will be discussed as well as current treatment options and recommended monitoring. Finally, the question of whether lipid abnormalities in youth with DM should be treated will be addressed.

A mathematical modeling of pulsatile flow in carotid artery bifurcation

Real carotid arteries are elastic and perfused with a non-Newtonian fluid. The blood flow is pulsatile characterized by the reverse flow regions at the non-divider wall of internal carotid artery and external carotid artery. A coupling effect between fluid flow and elastic deformation is introduced. In addition we have calculated volumetric flow rate, pressure gradient and Impedance due to pulsatile flow in elastic carotid artery. We analyzed the flow at various locations in common carotid artery and internal carotid artery for different frequencies 60, 90, 120 pulse/min and Reynolds number 500 using a compliance mismatch model of carotid artery. Reverse flow of blood increases the impedance and should not be discarded. The problem has been analyzed mathematically and the agreement between present results and the available literature was found to be quite satisfactory.

Respiratory infection recurrence and passive smoking in early atherosclerosis in children and adolescents with type 1 diabetes

Optimal glucose control in juvenile type 1 diabetes mellitus is necessary but not sufficient to reduce the burden of cardiovascular events in later life. This emphasizes the importance of searching for other possible risk factors associated with diabetes. We investigated whether recurrent episodes of acute respiratory infections and exposure to tobacco smoke could influence vascular phenotypes for early atherosclerosis in children and adolescents with type 1 diabetes. Common carotid artery elasticity and intima-media thickness along with circulating markers of lipid, inflammatory and glycaemic profiles were investigated in up to 98 children and adolescents with type 1 diabetes. The number of clinically manifest acute respiratory tract infections (RTI) during the past year, and the degree of exposure to environmental tobacco smoke (ETS), were assessed by separate questionnaires. Carotid artery compliance (CAC) was decreased in patients with high (>or= 4/year; n = 22) recurrence of RTI compared to the remaining patients (n = 40; P < 0.05). In a multivariate analysis, the number of RTI during the past year and HbA(1C) were independently associated with decreased CAC (P < 0.05 for both). The inverse relationship between RTI recurrence and CAC was strengthened by frequent exposure to ETS. High recurrence of respiratory infections in young type 1 diabetics is associated with increased stiffening of the carotid artery particularly in those often exposed to tobacco smoke.

Preterm birth and carotid diameter and stiffness in childhood

Low birthweight, either as a result of poor foetal growth or preterm birth, is a risk factor for stroke in adult life. Carotid stiffening, an early marker of atheromatous disease, has been found in low-birthweight children born at term. We hypothesized that carotid artery growth and dynamic properties are permanently affected by preterm birth. Carotid artery stiffness and dimensions in 56 school children, 39 born very preterm (mean gestational age [GA] 29 weeks) and 17 controls born at term, were studied by ultrasonic measurements of the pulsatile movements of the vessel wall. The carotid artery diameter was 6.4 mm both in children born preterm and at term (p=0.99). No difference in carotid stiffness was found. Within the preterm group, no differences could be seen between those born small for gestational age (SGA) or appropriate for gestational age (AGA). Carotid artery elasticity and structure are not altered after preterm birth. The mechanisms behind the increased stroke risk in adults born preterm remain unresolved.

Toll-like receptor 4 gene (Asp299Gly) polymorphism associates with carotid artery elasticity: The cardiovascular risk in young Finns study

Objective Early subclinical markers of atherosclerosis, such as carotid artery intima media thickness (IMT) and elasticity predict future coronary events. The G allele of the Toll-like receptor 4 (TLR-4) gene Asp299Gly polymorphism has been previously associated with decreased development of atherosclerosis and with lower risk of myocardial infractions. We wanted to examine the association of this polymorphism with carotid IMT and compliance in a population of young Finnish Caucasian adults. Methods Carotid artery IMT and elasticity indices of 2201 study subjects who participated in a randomized multicenter study (cardiovascular risk in young Finns study) were measured with ultrasound. The genotyping was performed using the TaqMan 5′-nuclease assay. Results According to multivariate linear regression analysis adjusted with potential confounders, the G allele carriers had significantly higher carotid arterial compliance, measured in increase of luminal diameter percentage in response to blood pressure rise of 10 mmHg, than did the AA homozygotes ( β = 0.099 with 95% CI 0.029–0.169 and p = 0.006). The difference between AA homozygotes and GG homozygotes was even more pronounced ( β = 0.382 with 95% CI 0.119–0.644 and p = 0.004). Variation in the TLR-4 genotype was not related with IMT. The results of the two independent study cohorts of Eastern and Western Finland were in accordance with the results of the whole combined study population. Conclusion The G allele of the TLR-4 gene Asp299Gly polymorphism is associated with increased carotid artery compliance in young adults. This beneficial effect of the G allele may reduce the risk of future cardiovascular events.