Common carotid arterial stiffness and the risk of ischaemic stroke

Carotid Atherosclerosis, Ultrasound and Lipoproteins

Carotid artery plaques are considered a measure of atherosclerosis and are associated with an increased risk of atherosclerotic cardiovascular disease, particularly ischemic strokes. Monitoring of patients with an elevated risk of stroke is critical in developing better prevention strategies. Non-invasive imaging allows us to directly see atherosclerosis in vessels and many features that are related to plaque vulnerability. A large body of evidence has demonstrated a strong correlation between some lipid parameters and carotid atherosclerosis. In this article, we review the relationship between lipids and atherosclerosis with a focus on carotid ultrasound, the most common method to estimate atherosclerotic load.

Risk factors of carotid plaque and carotid common artery intima-media thickening in a high-stroke-risk population

INTRODUCTION

To analyze the risk factors of carotid plaque (CP) and carotid common artery intima-media thickening (CCAIMT) and the association between the risk factors and CP numbers and the side of the CCAIMT in a high-stroke-risk population.

METHODS

Carotid ultrasonography was conducted in 2025 participants with high stroke risk. Participants were divided into different groups according to the results of the ultrasound. The risk factors and blood biochemical indices were recorded.

RESULTS

The presence of CP and CCAIMT were 38.9% and 24.8% respectively. Multivariate logistic regression indicated that the risk factors of CP were age, high LDL-C and FBG levels, male gender, stroke, diabetes, hypertension, and tobacco use. Compared with participants without CPs, the participants who were male, and older in age, with risk factors of tobacco use, diabetes, high LDL-C levels, and a family history of hypertension were likely to have a single CP, whereas the participants with risk factors of tobacco use, diabetes, hypertension, male gender, older age, high LDL-C levels, stroke and AF or valvulopathy were prone to have multiple CPs. The risk factors of CCAIMT were male gender, stroke, hypertension, diabetes, AF or valvulopathy, tobacco use and age. Compared with the N-CCAIMT subgroup, the risk factors of left CCAIMT were tobacco use, diabetes, male gender, and age. The risk factors of right CCAIMT were male gender, high FBG levels, age, AF or valvulopathy. The risk factors of dual CCAIMT were high frequency of drinking milk, tobacco use, male gender, age, stroke, and hypertension.

CONCLUSION

These findings revealed the risk factors of CP and CCAIMT, and an association between the risk factors and the CP numbers and the side of the CCAIMT.

Long-term Effects of high-doSe pitavaStatin on Diabetogenicity in comparison with atorvastatin in patients with Metabolic syndrome (LESS-DM): study protocol for a randomized controlled trial

Background

The diabetogenic action of statins remains a concern, particularly in patients at high risk for diabetes receiving intensive statin therapy. Despite the risk of diabetes with statin use being considered a potential class effect, recent studies have suggested that pitavastatin exerts neutral or favorable effects on diabetogenicity. However, no randomized trial has compared the long-term effects of pitavastatin with those of other statins on glycemic control in populations at high risk for diabetes. Hence, we aim to assess the long-term effects of pitavastatin in comparison with atorvastatin on glucose metabolism in patients with metabolic syndrome (MetS).

Methods/design

The Long-term Effects of high-doSe pitavaStatin on Diabetogenicity in comparison with atorvastatin in patients with Metabolic syndrome (LESS-DM) trial is a prospective, randomized, open-label, active control clinical trial of patients with MetS. We plan to randomize 500 patients with MetS (1:1) to receive high-dose pitavastatin (4 mg) or atorvastatin (20 mg) daily for 24 months. The primary endpoint will be the change in hemoglobin A1c after statin treatment. Secondary endpoints will include the following: (1) changes in biochemical markers, including insulin, C-peptide, homeostasis model assessment of insulin resistance and insulin secretion, and adiponectin; (2) changes in imaging parameters, including carotid elasticity metrics and indices of cardiac function; and (3) the incidence of clinical events, including new-onset diabetes and cardiovascular disease.

Discussion

In this trial, we will explore whether pitavastatin 4 mg does not disturb glucose metabolism in patients with MetS. It will also provide mechanistic information on statin type-dependent diabetogenic effects and surrogate data regarding vascular and cardiac changes achieved by intensive statin therapy.

Trial registration

ClinicalTrials.gov, NCT02940366. Registered on 19 October 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2229-4) contains supplementary material, which is available to authorized users.

A non-contact approach for PWV detection: application in a clinical setting

A need for screening methods for arteriosclerosis led to the development of several approaches to measure pulse wave velocity (PWV) being indicative of arterial stiffness. Carotid-femoral PWV (cfPWV) can be measured between common carotid artery (CCA) and femoral artery (FA) displaying the physiologically important stiffness of the conduit arteries. However, this measurement approach has several disadvantages, and a local PWV-measurement of CCA-stiffness has been proposed as an alternative in the past. In the presented pilot study, laser Doppler vibrometry (LDV) is used to measure PWV locally in the CCA (PWVLDV) in 48 patients aged between 48 and 70, with known atherosclerotic arterial disease: stabilized coronary artery disease (CAD), cerebro-vascular disease (CVD) or peripheral artery disease (PAD). Additionally, cfPWV, CCA distensibility coefficient (DC), CCA intima-media thickness (IMT), blood pressure (BP) and age were evaluated. LDV is a valid method for local PWV-measurement. The method is potentially easy to use, and causes no discomfort to the patient. PWVLDV correlates with age (R  =  0.432; p  =  0.002) as reported in related studies using other techniques, and measured values lay between 2.5 and 5.8 m s(-1), which is well in line with literature measures of local PWV in the CCA. In conclusion, PWVLDV potentially is a marker for arterial health, but more research in a larger and more homogeneous patient population is mandatory. In future studies, blood velocity measurements should be incorporated, as well as a reference method such as pulse wave imaging (PWI) or magnetic resonance imaging (MRI).

Difference in carotid artery elasticity in subjects with different brachial artery kinetic of vasodilatation

Increased carotid stiffness and impaired brachial artery flow-mediated dilatation (FMD) associate with cardiovascular events. We have previously reported three FMD patterns based on the time of maximal dilatation. The aim of the present study was to verify whether different FMD patterns associate with carotid artery stiffness. In all, 133 subjects were enrolled. All participants underwent complete clinical examination, blood sampling and ultrasound study. FMD was used as a measure of endothelial function. Based on the maximal brachial artery FMD, subjects were divided into Early dilators (peak FMD at 50 s), Late dilators (peak FMD over 50 s) and No dilators. Echo-Doppler evaluation of carotid arteries was performed in order to calculate elastic indexes (strain, β-stiffness index and distensibility). In all, 64 subjects were classified as Early FMD, 36 as Late FMD and 33 as No dilators. Age, gender and cardiovascular risk factors were comparable among three groups. Early FMD had higher values of strain compared with both Late and no Dilators (P<0.001). Furthermore, Early dilators showed a significantly lower stiffness and higher distensibility compared with Late and No dilators. No significant differences between Late FMD and No Dilators were detected. Our results demonstrate that common carotid artery elasticity indexes significantly differ among Early, Late and No dilators. Subjects with delayed or absent brachial artery dilatation have stiffer common carotid arteries compared with subjects with early dilatation. In conclusion, our research suggests that the assessment of the kinetics of FMD in a clinical setting might represent a useful screening tool to improve the cardiovascular risk stratification.

A systematic literature review of the effect of carotid atherosclerosis on local vessel stiffness and elasticity

OBJECTIVE

This systematic literature review sought to determine the effects of carotid atherosclerotic plaque on local arterial stiffness.

METHODS

MedLine, EMBASE, and grey literature were searched with the following term: ("atherosclerosis" or "carotid atherosclerosis" or "carotid artery disease" or "carotid plaque") AND ("distensibility" or "elasticity" or "stiffness" or "compliance") NOT ("pulse wave velocity" or "PWV" or "carotid-ankle" or "ankle-brachial" or "augmentation index" or "cardio-ankle" or "CAVI" or "flow mediated dilation" or "FMD"). Results were restricted to English language articles reporting local arterial stiffness in human subjects with carotid atherosclerosis.

RESULTS

Of the 1466 search results, 1085 abstracts were screened and 191 full-text articles were reviewed for relevance. The results of the 50 studies that assessed some measure of carotid arterial elasticity or stiffness in patients with carotid plaque were synthesized and reviewed.

DISCUSSION

A number of different measures of carotid elasticity were found in the literature. Regardless of which metric was used, the majority of studies found increased carotid stiffness (or decreased distensibility) to be associated with carotid plaque presence, the degree of atherosclerosis, and incident stroke.

CONCLUSION

Carotid artery mechanics are influenced by the presence of atherosclerotic plaque. The clinical applicability of carotid elasticity measures may be limited by the lack of reference values and standardized techniques.

Common Carotid Artery Stiffness Is Associated with Left Ventricular Structure and Function and Predicts First Hospitalization for Acute Heart Failure

AIMS

Proximal aortic stiffness may be more important than carotid-femoral pulse wave velocity (cf-PWV) in the pathogenesis of heart failure. The present study investigated the associations of common carotid artery (CCA) stiffness, which might be a surrogate for proximal aortic stiffness, with left ventricular (LV) structure and function, and the development of acute heart failure (AHF).

METHODS AND RESULTS

Outpatients without a history of heart failure (114 subjects aged 63.5 ± 17.5 years) were enrolled for comprehensive noninvasive cardiovascular examinations. The LV mass index, the LV ejection fraction (EF), and the ratio of the early diastolic transmitral flow velocity to the early septal mitral annular diastolic velocity (E/E') were measured by echocardiography. CCA mechanical properties, including the incremental elastic modulus (Einc), β stiffness index, CCA distensibility (CD) and circumferential strain (CS), were assessed by carotid artery ultrasonography. cf-PWV was measured by arterial tonometry. CD was significantly associated with the LV mass index, and all CCA stiffness indices were significantly associated with EF and E/E' independently of age, mean blood pressure, and cf-PWV. During a mean follow-up of 265 ± 106 days, 9 patients presented with AHF. Einc (hazard ratio 6.56, 95% confidence interval 1.64-26.26, by quartile analysis), CS (6.82, 1.70-27.35), and β stiffness index (3.91, 1.05-14.57) but not cf-PWV (1.62, 0.41-6.51) significantly predicted the events.

CONCLUSIONS

In patients at risk for heart failure, CCA stiffness was significantly associated with LV structure and function independently of cf-PWV. In addition, CCA stiffness but not cf-PWV predicted first AHF.

Measurement of subclinical carotid atherosclerosis may help in predicting risk for stroke in patients with diabetes

Diabetes is one of the most important risk factor for stroke and cardiovascular disease (CVD), especially in young patients. The control of classical vascular risk factors failed in terms of prevention of stroke in patients with diabetes. In addiction, in these patients the glycemic control showed a benefit on microvascular disease but lacked an established benefit in macrovascular disease. Therefore, implementations of effective stroke prevention strategies appear necessary in patients with diabetes. Ultrasound surrogate or intermediate markers of carotid atherosclerosis include carotid intima-media thickness (cIMT), carotid plaque (CP), and carotid stiffness (STIFF) have been demonstrated to increase in patients with diabetes and to be able to predict risk for stroke. In this editorial we discuss the opportunity to prevent the onset of vascular disease in their "preclinical or subclinical" stage in patients with higher risk for stroke such as diabetic patients.

Characterization of distensibility, plaque burden, and composition of the atherosclerotic carotid artery using magnetic resonance imaging

PURPOSE

Arterial distensibility is a marker that can measure vessel wall functional and structural changes resulting from atherosclerosis with applications including estimation of mechanical properties of the wall. We sought to assess the feasibility of using magnetic resonance imaging (MRI) to include wall distensibility in the characterization of atherosclerotic carotid arteries and to analyze the relationship between distensibility and morphological and compositional plaque features.

METHODS

Five healthy volunteers were imaged with a multiple-slice CINE MR sequence twice, within 24 h, to determine the interscan reproducibility of distensibility measurements. Twenty-one subjects with >15% carotid stenosis and the five healthy volunteers were imaged using a multicontrast carotid MRI protocol to characterize arterial wall morphology and composition. Normalized wall index (wall area∕total vessel area), maximum wall thickness and, if present, percentages of wall area occupied by calcification and lipid-rich necrotic core were determined. A multiple-slice CINE MR sequence was added to the multicontrast protocol to measure the distensibility coefficient (DC) at several locations spanning the bifurcation. The intraclass correlation coefficient (ICC) and the coefficient of variation were used to assess the reproducibility of DC measurements made on the healthy subjects. The DC was compared between arterial segments and between the healthy and diseased groups. Furthermore, within the diseased group, DC was correlated to plaque morphology and composition at each location as well as that averaged over the plaque.

RESULTS

Distensibility measurements were highly reproducible: ICC (95% confidence interval) was 0.998 (0.96-1.0) for the common carotid segment and 0.990 (0.92-1.0) for the internal carotid segment. In healthy volunteers, we found significantly higher distensibility in the common segment of the carotid artery compared to the internal carotid segment (mean ± SD = 4.56 ± 1.02 versus 3.56 ± 1.32 × 10(-5)∕Pa; p < 0.05). However, no segmental differences were seen in the diseased group (3.25 ± 1.84 versus 3.26 ± 1.60 × 10(-5)∕Pa; p = 0.607). Location-to-location changes in DC were not found to correlate to changes in the local plaque morphology or composition nor were average DC found to be associated with aggregate plaque features.

CONCLUSIONS

These results demonstrate the feasibility of MRI to measure distensibility in the carotid artery and to presumably detect changes in distensibility due to age and∕or disease. The results suggest that the effect of atherosclerosis on local distensibility may not strongly depend upon the specific underlying plaque features in mild to moderate stenotic carotid lesions though more diffuse or nonlocal changes in arterial distensibility could not be ruled out.

Effect of parathyroidectomy on subclinical cardiovascular disease in mild primary hyperparathyroidism

OBJECTIVE

We recently demonstrated that mild primary hyperparathyroidism (PHPT) is associated with increased carotid intima-media thickness (IMT) and stiffness, and increased aortic valve calcification. It is unclear whether parathyroidectomy (PTX) improves these abnormalities. The purpose of this study was to determine whether cardiovascular abnormalities in PHPT improve with PTX.

DESIGN

Forty-four patients with PHPT were studied using carotid ultrasound and transthoracic echocardiography before and after PTX. Carotid IMT, carotid plaque and stiffness, left ventricular mass index (LVMI), myocardial and valvular calcification, and diastolic function were measured before, 1- and 2-year post-PTX.

RESULTS

Two years after PTX, increased carotid stiffness tended to decline to the normal range (17%, P=0.056) while elevated carotid IMT did not improve. Carotid plaque number and thickness, LVMI and cardiac calcifications did not change after PTX, while some measures of diastolic function (isovolumic relaxation time (IVRT) and tissue Doppler peak early diastolic velocity) worsened within the normal range. Indices did improve in patients with cardiovascular abnormalities at baseline. Increased carotid stiffness improved by 28% (P=0.004), a decline likely to be of clinical significance. More limited improvements also occurred in elevated IMT (3%, P=0.017) and abnormal IVRT (13%, P<0.05), a measure of diastolic dysfunction.

CONCLUSIONS

In mild PHPT, PTX led to modest changes in some cardiovascular indices. Improvements were mainly evident in those with preexisting cardiovascular abnormalities, particularly elevated carotid stiffness. These findings are reassuring with regard to current international guidelines that do not include cardiovascular disease as a criterion for PTX.

Vascular and autonomic function in preschool-aged children with congenital heart disease

OBJECTIVE

To compare indices of vascular health and heart rate variability in preschool-aged children with repaired congenital heart disease (CHD) including tetralogy of Fallot (n = 6) and coarctation of the aorta (n = 6).

DESIGN

  A cross-sectional study design was used. All measures were noninvasive and collected over a single testing session under the supervision of a parent/guardian.

SETTING

  Data collection took place in a quiet, temperature-controlled room (23°± 1°C) with the participant in a supine position.

PATIENTS

  Twelve (six females, six males) preschool-aged children with repaired CHD (CHD: 4 ± 1 years) and 12 age- and gender-matched healthy controls (CON: 5 ± 1 years) participated in the study.

OUTCOME MEASURES

  Supine, resting measures of heart rate variability (time, frequency, and nonlinear domains), whole-body pulse wave velocity (ventricular depolarization to dorsalis pedis artery), brachial blood pressures, and carotid artery distensibility, lumen diameter, intima-media thickness, and wall/lumen ratio were collected in both groups.

RESULTS

  The groups were similar in age, height, and weight; however, CON had significantly higher body mass index values (CON: 16.9 ± 2.2, CHD: 15.1 ± 1.0, P < .05) and body mass index percentiles (CON: 69 ± 27%tile, CHD: 36 ± 24%tile, P < .01) compared to CHD. No group differences were found for resting brachial blood pressures, whole-body pulse wave velocity, heart rate variability, and carotid artery distensibility, lumen diameter, and intima-media thickness (P > .05). Carotid artery pulse pressures (CHD: 38 ± 6 mm Hg, CON: 31 ± 6 mm Hg, P < .05) and wall/lumen ratios (CHD: 0.091 ± 0.007, CON: 0.085 ± 0.006, P < .01) were significantly higher in the CHD group.

CONCLUSIONS

  These results may indicate that preschool-aged children with repaired CHD display early signs of vascular remodeling, but not autonomic or vascular dysfunction. The effects of larger wall/lumen ratios on cardiovascular disease risk require further investigation.

Short-term effect of atorvastatin on carotid artery elasticity: a pilot study

BACKGROUND AND PURPOSE

Few studies have examined the early effects of statins on carotid artery elasticity, a potential surrogate marker of cardiovascular risk. This study examined the short-term effects of atorvastatin 80 mg daily on carotid elasticity measured by high-resolution B-mode ultrasound.

METHODS

The study included 40 stroke-free and statin-naive subjects older than age 45 (mean age, 70±7 years; 55% men; 64% Caribbean-Hispanic). Outcome measures included carotid stiffness indices at 14 and 30 days after initiation of treatment. The systolic and diastolic diameters of the right common carotid artery were averaged from multiple B-mode imaging frames. Absolute and relative changes of strain [(systolic diameter-diastolic diameter)/diastolic diameter], stiffness (β) [ln (systolic/diastolic blood pressure)/strain], and distensibility (1/β adjusted for wall thickness) from baseline were compared by the repeated measures t test and were considered significant at α=0.05.

RESULTS

Baseline mean stiffness was 0.08 (95% confidence interval [CI], 0.06-0.10). It significantly decreased at day 30 to 0.05 (CI, 0.04-0.06; P<0.01). Mean baseline distensibility was 15.25 (CI, 13.18-17.32), increasing significantly at day 30 to 17.23 (CI, 14.01-20.45; P<0.05). An improvement in distensibility of ≥10% from baseline was observed in 29 (73%) subjects. Changes in stiffness and distensibility were maximal among subjects with baseline low-density lipoprotein levels<130 mg/dL.

CONCLUSIONS

Short-term treatment with high-dose atorvastatin was associated with improvement in the carotid elasticity metrics. Carotid artery elasticity measured by B-mode ultrasound is a simple noninvasive measure of arterial wall function and may be a useful surrogate end point in clinical trials targeting individuals at increased risk for atherosclerosis.

Noninvasive measures of vascular health are reliable in preschool-aged children

Measures of vascular health are known to be important predictors of cardiovascular disease in adulthood. The reliability of commonly used measures of vascular health has been demonstrated in school-aged children, adolescents, and adults; however, their reliability in preschool-aged children remains to be determined. Twenty 2- to 6-year-old children participated in 2 identical testing sessions on different days. Following 10 min of supine rest, carotid artery blood pressures and common carotid artery images were assessed simultaneously for 10 heart cycles, using applanation tonometry and B-mode ultrasound, respectively, while electrocardiogram (ECG) and infrared measures of arterial pressure waves at the dorsalis pedis were recorded continuously. Brachial artery blood pressures were determined using an automated oscillometric device. Carotid artery diameters and intima-media thickness (IMT) were analyzed using a semiautomated detection software program. Carotid compliance, distensibility, and stiffness index were calculated from carotid diameters and carotid blood pressures. Whole-body pulse-wave velocity (PWV) was determined from the time delay between the R spike of the ECG and the foot of the dorsalis pedis arterial pressure wave. Reliability of all measures was assessed using the coefficient of variation (CV) and the intraclass correlation coefficient (ICC). The most reliable measures were carotid artery IMT and PWV with CVs of 2.6% and 3.5% and ICCs of 0.86 and 0.76, respectively. The lower reliability of carotid compliance and distensibility (ICC ≤ 0.63) is likely attributable to the variability of blood pressure measurements. This study confirms that vascular measurements demonstrate substantial reliability in preschool-aged children as young as 2 years.

Carotid vascular abnormalities in primary hyperparathyroidism

CONTEXT

Data on the presence, extent, and reversibility of cardiovascular disease in primary hyperparathyroidism (PHPT) are conflicting.

OBJECTIVE

This study evaluated carotid structure and function in PHPT patients compared with population-based controls.

DESIGN

This is a case-control study.

SETTING

The study was conducted in a university hospital metabolic bone disease unit.

PARTICIPANTS

Forty-nine men and women with PHPT and 991 controls without PHPT were studied.

OUTCOME MEASURES

We measured carotid intima-media thickness (IMT), carotid plaque presence and thickness, and carotid stiffness, strain, and distensibility.

RESULTS

IMT, carotid plaque thickness, carotid stiffness, and distensibility were abnormal in PHPT patients, and IMT was higher in patients than controls (0.959 vs. 0.907 mm, P < 0.0001). In PHPT, PTH levels, but not calcium concentration, predicted carotid stiffness (P = 0.04), strain (P = 0.06), and distensibility (P = 0.07). Patients with increased carotid stiffness had significantly higher PTH levels than did those with normal stiffness (141 +/- 48 vs. 94.9 +/- 44 pg/ml, P = 0.002), and odds of abnormal stiffness increased 1.91 (confidence interval = 1.09-3.35; P = 0.024) for every 10 pg/ml increase in PTH, adjusted for age, creatinine, and albumin-corrected calcium.

CONCLUSIONS

Mild PHPT is associated with subclinical carotid vascular manifestations. IMT, a predictor of cardiovascular outcomes, is increased. Measures of carotid stiffness are associated with extent of PTH elevation, suggesting that those with more severe PHPT may have impaired vascular compliance and that PTH, rather than calcium, is the mediator.

Increased arterial stiffness in nonobese women with polycystic ovary syndrome (PCOS) without comorbidities: one more characteristic inherent to the syndrome?

BACKGROUND

Polycystic ovary syndrome (PCOS) is associated with adverse metabolic effects. Some cardiovascular disease (CVD) risk markers are increased in women with PCOS. However, early markers of atherosclerosis are also associated with obesity and insulin resistance, which are related to PCOS. These markers may result either directly from PCOS or indirectly as a consequence of the comorbidities associated with the syndrome.

CONTEXT

To assess the presence of early CVD markers in young, nonobese women with PCOS.

PATIENTS

Forty women with PCOS and 50 healthy women with regular menstrual cycles, matched for age and body mass index (BMI).

MEASUREMENTS

The following CVD markers were assessed by ultrasonography: common carotid artery (CCA) stiffness index (beta), distensibility and intima-media thickness (IMT), and brachial artery flow-mediated dilatation (FMD). Inflammatory markers, including interleukin (IL)-6, tumour necrosis factor (TNF)-alpha, homocysteine, C-reactive protein (CRP), glycaemia, lipid profile and insulin, were also assessed.

RESULTS

CCA beta was higher in PCOS than in control women (3.72 +/- 0.96 vs. 3.36 +/- 0.96, P = 0.04) and CCA distensibility was lower (0.31 +/- 0.08 vs. 0.35 +/- 0.09 mmHg(-1), P = 0.02). Waist circumference, total testosterone and the Free Androgen Index (FAI) were higher in PCOS patients than in controls (78.2 +/- 10.0 vs. 71.5 +/- 7.2 cm, P = 0.001; 88.1 +/- 32.4 vs. 57.1 +/- 21.2 ng/dl, P < 0.01; 12.7 +/- 15.7%vs. 4.7 +/- 2.3%, P < 0.01, respectively), while SHBG was reduced (37.9 +/- 19.1 vs. 47.8 +/- 18.3 nmol/l, P = 0.01). The remaining variables did not differ between the groups.

CONCLUSIONS

Young women with PCOS exhibit changes in vascular elasticity even in the absence of classical risk factors for CVD, such as hypertension and obesity.

Brachial artery pulsatility index change 1 minute after 5-minute forearm compression: comparison with flow-mediated dilatation

OBJECTIVE

Endothelial impairment evaluation by sonographic measurement of flow-mediated dilatation (FMD) has become broadly used. However, this method has 2 main caveats: the dilatation depends on the baseline arterial diameter, and a high precision level is required. Vasodilatation leads to an amplified fall in impedance. We hypothesized that assessment of the pulsatility index change (PI-C) 1 minute after 5-minute forearm compression might evaluate that fall in impedance. The aim of this study was to compare the PI-C with FMD.

METHODS

Flow-mediated dilatation and the PI-C were assessed in 51 healthy women aged between 35.1 and 67.1 years. We correlated both FMD and the PI-C with age, body mass index, waist circumference, cholesterol level, high-density lipoprotein level, glucose level, systolic and diastolic blood pressure, pulse pressure, brachial artery diameter, simplified Framingham score, intima-media thickness, and carotid stiffness index. Intraclass correlation coefficients between 2 FMD and PI-C measurements were also examined.

RESULTS

Only FMD correlated with baseline brachial diameter (r = -0.53). The PI-C had a high correlation with age, body mass index, waist circumference, cholesterol level, systolic blood pressure, pulse pressure, simplified Framingham score, and intima-media thickness. The correlation between FMD and the PI-C was high (r = -0.66). The PI-C had a higher intraclass correlation coefficient (0.991) than FMD (0.836) but not brachial artery diameter (0.989).

CONCLUSIONS

The PI-C had a large correlation with various markers of cardiovascular risk. Additionally, PI-C measurement does not require offline analysis, extra software, or electrocardiography. We think that the PI-C could be considered a marker of endothelial function. However, more studies are required before further conclusions.

Profile and associations of central pulse wave velocity and central pulse pressure among ischemic stroke patients

Arterial stiffness, a known risk factor for atherosclerosis, can be measured directly with carotid-femoral pulse wave velocity (CPWV) and indirectly with central pulse pressure (CPP). We aimed to compare central and brachial pulse pressures, and to profile CPWV and CPP among ischemic stroke patients. We studied 198 consecutive prospective ethnic Chinese and South Asian ischemic stroke patients, measuring brachial pressures, central pressures and CPWV under standardized conditions using established methods. The mean CPWV was 11.6 +/- 3.2 m/s and CPP was 64 +/- 28 mmHg. CPP was significantly lower than brachial pulse pressure. CPWV and CPP were both independently associated with older age and hypertension. Among ischemic stroke patients, brachial pulse pressure cannot be used as a surrogate for CPP. Older age and hypertension are associated with arterial stiffening.

Carotid artery distensibility: a reliability study

OBJECTIVE

Carotid distensibility (CD) is a measure of carotid artery elasticity that has been introduced as a risk factor for cardiovascular disease. Information regarding reproducibility of sonographic CD measures is limited. The objective of this study was to evaluate the inter-reader reliability of sonographic measurements of common carotid artery (CCA) diameters and derived metrics of CD.

METHODS

Two independent readers (R1 and R2) measured the systolic diameter (SD) and diastolic diameter (DD) for the right CCA from the B/M-mode sonographic registrations among 118 subjects. The derived CD metrics (strain, elastic modulus [E], stiffness [beta], and CD) were calculated. The inter-reader type 3 intraclass correlation coefficients (ICC3,1) for carotid diameters were calculated.

RESULTS

The mean SDs +/- standard deviation were 7.15 +/- 1.43 mm for R1 and 7.24 +/- 1.43 mm for R2. The mean DDs were 6.71 +/- 1.36 mm for R1 and 6.68 +/- 1.41 mm for R2. The mean differences of SD and DD between R1 and R2 were 0.08 +/- 0.40 mm (paired t test, P = .04) and 0.03 +/- 0.43 mm (paired t test, P = .46), respectively. Inter-reader type 3 intraclass correlation coefficients were 0.96 for SD and 0.95 for DD. We observed a significant association of demographics with carotid diameters but not with derived CD metrics or risk factors.

CONCLUSIONS

Our results suggest good reproducibility of CCA diameters measured with B/M-mode sonography. However, very small changes in linear measurements of carotid diameters can have big effects on estimates of arterial mechanical properties such as strain and Young's modulus. The standard boundary identification methods may not be precise and reproducible enough for use in a clinical setting.

Carotid arterial stiffness is marginally higher in the metabolic syndrome and markedly higher in type 2 diabetes mellitus in patients with manifestations of arterial disease

INTRODUCTION

Insulin resistance is generally considered to be of major importance in the pathophysiology of the metabolic syndrome and type 2 diabetes mellitus, both high-risk conditions for cardiovascular complications. Carotid artery stiffness is increasingly recognized as an important predictor of cardiovascular morbidity and mortality. Therefore, in the present study we determined whether the metabolic syndrome (MetSyn) and type 2 diabetes mellitus (DM2) are associated with carotid artery stiffness in patients with already clinical manifestations of arterial disease.

METHODS AND RESULTS

A cross-sectional study in 2105 patients with manifest arterial disease (cerebral, coronary or peripheral artery disease, renal artery stenosis or an aneurysm of the abdominal aorta) was performed. The difference in carotid stiffness between patients with and without MetSyn and with and without DM2 was studied with linear regression analysis. Compared to patients without DM2 (N=1112), patients with DM2 (N=301) had significantly higher arterial stiffness (distension -18.5 (-35.1;-1.9) 95% CI/distensibility -1.8 (-2.2;-1.4) 95% CI). Generally, there was a trend of higher carotid stiffness in patients with MetSyn (N=922) compared to patients without (N=1112) MetSyn (distension -9.6 (-21.5;2.3) 95% CI/distensibility -2.0 (-2.6;-1.4) 95% CI). Excluding the patients with also DM2 (N=230) from the MetSyn-group diminished this relation (distension -5.7 (-18.8;7.4) 95% CI/distensibility -1.1 (-1.6;-0.6) 95% CI). Furthermore, in the population as a whole, carotid artery stiffness increased with increasing number of components of the metabolic syndrome (p=0.08 for distension/p< or =0.001 for distensibility). In addition, this association was not as clear after exclusion of the patients with DM2 from the MetSyn-group (p=0.24 for distension/p<0.001 for distensibility). From all the components of the MetSyn only high blood pressure and high fasting glucose influenced the carotid artery stiffness.

CONCLUSIONS

We concluded that (increasing number of components of) the metabolic syndrome were associated with marginally higher carotid artery stiffness, while type 2 diabetes was associated with a marked increase in carotid artery stiffness, in patients with already clinical manifestations of arterial disease.

Migraine Is Associated with Enhanced Arterial Stiffness

Migraine is a common subtype of headache. Epidemiological studies have revealed that migraine could be an independent risk factor for ischemic stroke even in elderly subjects. Arterial stiffness is one of the major pathophysiological bases of stroke. In the present study, we cross-sectionally investigated the possible relationship between migraine and arterial stiffness in community-dwelling subjects. The study subjects were independently recruited from two sources (Group A, n=134, 68+/-5 years; Group B, n=138, 68+/-7 years). Augmentation index (AI), the ratio of augmented pressure by the reflection pressure wave to the pulse pressure, was obtained from the radial arterial waveform as an index of arterial stiffness. Brachial blood pressure was also measured simultaneously. Migraine was diagnosed using a previously validated questionnaire. The prevalence of migraine was 5.2% (Group A) and 16.7% (Group B). Subjects with migraine had higher radial AI in both Group A (migraine, 101+/-15%; other headache, 88+/-12%; no headache, 86+/-12%, p=0.003) and Group B (95+/-11%, 90+/-11%, 91+/-14%, p=0.058). Multiple linear regression analysis revealed that migraine was an independent determinant of AI (beta=0.154, p=0.002) after adjustment for other confounding factors: age (beta=-0.024, p=0.654); sex (beta=0.141, p=0.069); body height (beta=-0.215, p=0.005); systolic blood pressure (beta=0.174, p=0.001); medication for hypertension, hyperlipidemia, and diabetes mellitus (beta=-0.014, p=0.787); and heart rate (beta=-0.539, p<0.001). In a separate analysis by sex, migraine was also a significant determinant for AI (male, beta=0.246, p=0.019; female, beta=0.159, p=0.008). Migraine in the elderly could be a clinical manifestation of enhanced arterial stiffness.