Ethnic differences in carotid artery diameter and stiffness: the Northern Manhattan Study

Estimated Pulse-Wave Velocity and Magnetic Resonance Imaging Markers of Cerebral Small-Vessel Disease in the NOMAS

BACKGROUND

Pulse-wave velocity is a measure of arterial stiffness and a risk factor for cardiovascular disease. Recently, an estimated pulse-wave velocity (ePWV) was introduced that was predictive of increased risk of cardiovascular disease. Our objective was to determine whether ePWV was associated with cerebral small-vessel disease on magnetic resonance imaging.

METHODS AND RESULTS

We included 1257 participants from the NOMAS (Northern Manhattan Study). The ePWV values were calculated using a nonlinear function of age and mean arterial blood pressure. The association between ePWV and white matter hyperintensity volume was assessed. Modification by race and ethnicity was evaluated. Associations between ePWV and other cerebral small-vessel disease markers, covert brain infarcts, cerebral microbleeds, and enlarged perivascular spaces, were explored as secondary outcomes. Mean±SD age of the cohort was 64±8 years; 61% were women; 18% self-identified as non-Hispanic Black, 67% as Hispanic, and 15% as non-Hispanic White individuals. Mean±SD ePWV was 11±2 m/s in the total NOMAS population and was similar across race and ethnic groups. The ePWV was significantly associated with white matter hyperintensity volume (β=0.23 [95% CI, 0.20-0.26]) after adjustment. Race and ethnicity modified the association between ePWV and white matter hyperintensity volume, with stronger associations in Hispanic and non-Hispanic Black individuals. Significant associations were found between ePWV and covert brain infarcts, cerebral microbleeds, and perivascular spaces after adjustment.

CONCLUSIONS

The ePWV function may provide a vascular mechanism for deleterious cerebrovascular outcomes in individuals with cerebral small-vessel disease and is particularly apparent in the racial and ethnic minorities represented in the NOMAS cohort.

Reference values of carotid intima-media thickness and arterial stiffness in Chinese adults based on ultrasound radio frequency signal: A nationwide, multicenter study

BACKGROUND

Carotid intima-media thickness (IMT) and diameter, stiffness, and wave reflections, are independent and important clinical biomarkers and risk predictors for cardiovascular diseases. The purpose of the present study was to establish nationwide reference values of carotid properties for healthy Chinese adults and to explore potential clinical determinants.

METHODS

A total of 3053 healthy Han Chinese adults (1922 women) aged 18-79 years were enrolled at 28 collaborating tertiary centers throughout China between April 2021 and July 2022. The real-time tracking of common carotid artery walls was achieved by the radio frequency (RF) ultrasound system. The IMT, diameter, compliance coefficient, β stiffness, local pulse wave velocity (PWV), local systolic blood pressure, augmented pressure (AP), and augmentation index (AIx) were then automatically measured and reported. Data were stratified by age groups and sex. The relationships between age and carotid property parameters were analyzed by Jonckheere-Terpstra test and simple linear regressions. The major clinical determinants of carotid properties were identified by Pearson's correlation, multiple linear regression, and analyses of covariance.

RESULTS

All the parameters of carotid properties demonstrated significantly age-related trajectories. Women showed thinner IMT, smaller carotid diameter, larger AP, and AIx than men. The β stiffness and PWV were significantly higher in men than women before forties, but the differences reversed after that. The increase rate of carotid IMT (5.5 μm/year in women and 5.8 μm/year in men) and diameter (0.03 mm/year in both men and women) were similar between men and women. For the stiffness and wave reflections, women showed significantly larger age-related variations than men as demonstrated by steeper regression slopes (all P for age by sex interaction <0.05). The blood pressures, body mass index (BMI), and triglyceride levels were identified as major clinical determinants of carotid properties with adjustment of age and sex.

CONCLUSIONS

The age- and sex-specific reference values of carotid properties measured by RF ultrasound for healthy Chinese adults were established. The blood pressures, BMI, and triglyceride levels should be considered for clinical application of corresponding reference values.

The role of sirtuins and uncoupling proteins on vascular aging: The Northern Manhattan Study experience

Aging affects all organs. Arteries, in particular, are among the most affected. Vascular aging (VA) is defined as age-associated changes in function and structure of vessels. Classical VA phenotypes are carotid intima-media thickness (IMT), carotid plaque (CP), and arterial stiffness (STIFF). Individuals have different predisposition to these VA phenotypes and their associated risk of cardiovascular events. Some develop an early vascular aging (EVA), and others are protected and identified as having supernormal vascular aging (SUPERNOVA). The mechanisms leading to these phenotypes are not well understood. In the Northern Manhattan Study (NOMAS), we found genetic variants in the 7 Sirtuins (SIRT) and 5 Uncoupling Proteins (UCP) to be differently associated with risk to developing VA phenotypes. In this article, we review the results of genetic-epidemiology studies to better understand which of the single nucleotide polymorphisms (SNPs) in SIRT and UCP are responsible for both EVA and SUPERNOVA.

Assessing the Adequacy of Superficial Temporal Artery Blood Flow in Korean Patients Undergoing STA-MCA Anastomosis

OBJECTIVE

Superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis is conducted for flow augmentation. In this study, we measured the STA cut flow of a Korean population and evaluated the relationship between STA cut flow and long-term patency of the bypass.

METHODS

A retrospective study was conducted. Intraoperative measurement of STA flow was conducted using a microvascular flow meter on patients who underwent STA-MCA. After cutting the distal end, the STA flow rate was measured with no resistance and recorded. After finishing anastomosis, STA flow was measured and recorded. The cut flow index was calculated by dividing post anastomosis flow by cut flow in intracranial atherosclerotic stenosis patients.

RESULTS

The median STA cut flow was 35.0 mL/min and the post anastomosis flow was 24.0 mL/min. The cut flow of STA decreased with aging (p=0.027) and increased with diameter (p=0.004). The cut flow showed no correlation with history of hypertension or diabetes mellitus (p=0.713 and p=0.786), but did correlate a positively with history of hyperlipidemia (p=0.004). There were no statistical differences in cut flow, STA diameter, and post anastomosis flow between the frontal and parietal branches (p=0.081, p=0.853, and p=0.990, respectively).

CONCLUSION

The median STA cut flow of a Korean population was 35 mL/min. Upon reviewing previous articles, it appears that there are differences in the STA cut flow between Western and Asian patients.

Central and local arterial stiffness in White Europeans compared to age-, sex-, and BMI-matched South Asians

BACKGROUND

Ethnicity impacts cardiovascular disease (CVD) risk, and South Asians demonstrate a higher risk than White Europeans. Arterial stiffness is known to contribute to CVD, and differences in arterial stiffness between ethnicities could explain the disparity in CVD risk. We compared central and local arterial stiffness between White Europeans and South Asians and investigated which factors are associated with arterial stiffness.

METHODS

Data were collected from cohorts of White Europeans (the Netherlands) and South Asians (India). We matched cohorts on individual level using age, sex, and body mass index (BMI). Arterial stiffness was measured with ARTSENS® Plus. Central stiffness was expressed as carotid-femoral pulse wave velocity (cf-PWV, m/s), and local carotid stiffness was quantified using the carotid stiffness index (Beta) and pressure-strain elastic modulus (Epsilon, kPa). We compared arterial stiffness between cohorts and used multivariable linear regression to identify factors related to stiffness.

RESULTS

We included n = 121 participants per cohort (age 53±10 years, 55% male, BMI 24 kg/m2). Cf-PWV was lower in White Europeans compared to South Asians (6.8±1.9 vs. 8.2±1.8 m/s, p<0.001), but no differences were found for local stiffness parameters Beta (5.4±2.4 vs. 5.8±2.3, p = 0.17) and Epsilon (72±35 vs. 70±31 kPa, p = 0.56). Age (standardized β, 95% confidence interval: 0.28, 0.17-0.39), systolic blood pressure (0.32, 0.21-0.43), and South Asian ethnicity (0.46, 0.35-0.57) were associated with cf-PWV; associations were similar between cohorts (p>0.05 for interaction). Systolic blood pressure was associated with carotid stiffness in both cohorts, whereas age was associated to carotid stiffness only in South Asians and BMI only in White Europeans.

CONCLUSION

Ethnicity is associated with central but not local arterial stiffness. Conversely, ethnicity seems to modify associations between CVD risk factors and local but not central arterial stiffness. This suggests that ethnicity interacts with arterial stiffness measures and the association of these measures with CVD risk factors.

Racial and Ethnic Differences in the Association Between Classical Cardiovascular Risk Factors and Common Carotid Intima-Media Thickness: An Individual Participant Data Meta-Analysis

Background The major risk factors for atherosclerotic cardiovascular disease differ by race or ethnicity but have largely been defined using populations of European ancestry. Despite the rising prevalence of cardiovascular disease in Africa there are few related data from African populations. Therefore, we compared the association of established cardiovascular risk factors with carotid-intima media thickness (CIMT), a subclinical marker of atherosclerosis, between African, African American, Asian, European, and Hispanic populations. Methods and Results Cross-sectional analyses of 34 025 men and women drawn from 15 cohorts in Africa, Asia, Europe, and North America were undertaken. Classical cardiovascular risk factors were assessed and CIMT measured using B-mode ultrasound. Ethnic differences in the association of established cardiovascular risk factors with CIMT were determined using a 2-stage individual participant data meta-analysis with beta coefficients expressed as a percentage using the White population as the reference group. CIMT adjusted for risk factors was the greatest among African American populations followed by Asian, European, and Hispanic populations with African populations having the lowest mean CIMT. In all racial or ethnic groups, men had higher CIMT levels compared with women. Age, sex, body mass index, and systolic blood pressure had a significant positive association with CIMT in all races and ethnicities at varying magnitudes. When compared with European populations, the association of age, sex, and systolic blood pressure with CIMT was weaker in all races and ethnicities. Smoking (beta coefficient, 0.39; 95% CI, 0.09-0.70), body mass index (beta coefficient, 0.05; 95% CI, 0.01-0.08) and glucose (beta coefficient, 0.13; 95% CI, 0.06-0.19) had the strongest positive association with CIMT in the Asian population when compared with all other racial and ethnic groups. High-density lipoprotein-cholesterol had significant protective effects in African American (beta coefficient, -0.31; 95% CI, -0.42 to -0.21) and African (beta coefficient, -0.26; 95% CI, -0.31 to -0.19) populations only. Conclusions The strength of association between established cardiovascular risk factors and CIMT differed across the racial or ethnic groups and may be due to lifestyle risk factors and genetics. These differences have implications for race- ethnicity-specific primary prevention strategies and also give insights into the differential contribution of risk factors to the pathogenesis of cardiovascular disease. The greatest burden of subclinical atherosclerosis in African American individuals warrants further investigations.

Systemic Arterial Correlates of Cervical Carotid Artery Tortuosity : The Northern Manhattan Study

INTRODUCTION

The association between cervical internal carotid artery (cICA) tortuosity and atherosclerosis is a matter of debate. Additionally, some genetic syndromes characterized by connective tissue remodeling are associated with arterial tortuosity, raising the possibility that cICA tortuosity may not only be atherosclerotic. In this study, we hypothesized that cICA tortuosity is not associated with imaging biomarkers of atherosclerosis.

METHODS

The Northern Manhattan Study (NOMAS) was a prospective, multiethnic cohort of stroke-free individuals who underwent brain MRA, carotid ultrasound and transthoracic echocardiogram from 2003-2008. The cICA tortuosity was scored in each carotid as 0 = no tortuosity, 1 = tortuosity <90°, 2 = tortuosity ≥90°. A summary cICA tortuosity score (possible range 0-4) was created by adding up the tortuosity score from each carotid. Participants were assessed for atherosclerotic markers by using B‑mode carotid sonography and transthoracic echocardiography.

RESULTS

Of 558 participants 178 (31.9%) had any cervical ICA tortuosity (tortuosity score >0). The cICA tortuosity score was higher in women and was associated with diastolic and systolic blood pressures and height (all P < 0.05). In models adjusted for demographics and risk factors, only the association with diastolic blood pressure remained significant (β = 0.002, P = 0.02). Similarly, cICA tortuosity was associated with larger aortic root diameter (B = 1.03 ± 0.36, P = 0.004) but not with other markers of carotid or aortic atherosclerosis.

CONCLUSION

Cervical ICA tortuosity is associated with a higher diastolic blood pressure and larger aortic root diameter but not with other measures of atherosclerosis. Determining the risks of vascular events associated with this non-atherosclerotic phenotype may help for a better risk stratification for individuals with cICA tortuosity.

Blood Pressure and Stroke: A Review of Sex- and Ethnic/Racial-Specific Attributes to the Epidemiology, Pathophysiology, and Management of Raised Blood Pressure

Raised blood pressure (BP) is the leading cause of death and disability worldwide, and its particular strong association with stroke is well established. Although systolic BP increases with age in both sexes, raised BP is more prevalent in males in early adulthood, overtaken by females at middle age, consistently across all ethnicities/races. However, there are clear regional differences on when females overtake males. Higher BP among males is observed until the seventh decade of life in high-income countries, compared with almost 3 decades earlier in low- and middle-income countries. Females and males tend to have different cardiovascular disease risk profiles, and many lifestyles also influence BP and cardiovascular disease in a sex-specific manner. Although no hypertension guidelines distinguish between sexes in BP thresholds to define or treat hypertension, observational evidence suggests that in terms of stroke risk, females would benefit from lower BP thresholds to the magnitude of 10 to 20 mm Hg. More randomized evidence is needed to determine if females have greater cardiovascular benefits from lowering BP and whether optimal BP is lower in females. Since 1990, the number of people with hypertension worldwide has doubled, with most of the increase occurring in low- and-middle-income countries where the greatest population growth was also seen. Sub-Saharan Africa, Oceania, and South Asia have the lowest detection, treatment, and control rates. High BP has a more significant effect on the burden of stroke among Black and Asian individuals than Whites, possibly attributable to differences in lifestyle, socioeconomic status, and health system resources. Although pharmacological therapy is recommended differently in local guidelines, recommendations on lifestyle modification are often very similar (salt restriction, increased potassium intake, reducing weight and alcohol, smoking cessation). This overall enhanced understanding of the sex- and ethnic/racial-specific attributes to BP motivates further scientific discovery to develop more effective prevention and treatment strategies to prevent stroke in high-risk populations.

Comparison of cardiac CT angiography coronary artery dimensions and ethnicity in Trinidad: the CADET pilot study

BACKGROUND

This study aimed to determine if there were any significant differences in coronary artery (CA) dimensions at prespecified segments during cardiac CT angiography (CCTA) compared with ethnicity at an academic tertiary medical centre in Trinidad and Tobago.

METHODS

Patients (n=170) who underwent CCTA from July 2016 to June 2021 at the Eric Williams Medical Sciences Complex were selected based on predefined selection criteria. The size of the left main and proximal, mid and distal diameters of the left anterior descending, left circumflex and right coronary artery (RCA) were measured using quantitative coronary angiography, syngo.CT Coronary Analysis (Siemens Healthineers AG, Erlangen, Germany). Routine medical history, cardiovascular medications and anthropometric data were also recorded. Comparisons were performed using an independent sample t-test and analysis of variance for continuous variables.

RESULTS

One hundred and seventy participants were enrolled in this study. There were no statistically significant associations between gender and CA dimensions; however, there were significant associations between South Asian and Caribbean black ethnicities for almost all CA dimensions except for the distal RCA segment. These findings were replicated when the analysis was adjusted for body surface area with the addition of the mid-RCA segment, which was bordering near-significance (p value 0.051).

CONCLUSIONS

Significantly smaller CA dimensions were observed in South Asian patients compared with Caribbean black patients undergoing CCTA. This pilot study could be clinically significant for Trinidadian patients at risk of developing coronary artery disease.

TRIAL REGISTRATION NUMBER

NCT04774861.

Sex-specific prediction value of common carotid artery diameter for stroke risk in a hypertensive population: a cross-sectional study

BACKGROUND

The importance of sex as a risk factor for stroke has been established. This study aimed to assess sex-related disparities in carotid artery diameter and stroke in a hypertensive population.

METHODS

The cross-sectional survey was conducted in rural areas of northeast China. A multistage cluster sampling method was employed to select a representative population. The study comprised 3,245 individuals with hypertension. The common carotid artery (CCA) interadventitial diameter was measured by ultrasound. A linear model of restricted cubic spline function was used to characterize the concentration-response (C-R) relationship between CCA diameter and stroke.

RESULTS

The overall prevalence of stroke was 8.9% among hypertensive individuals, with a higher rate in men than in women (10.8% vs. 7.6%). When the women's CCA diameters were divided into quartiles, the top quartile (>8.10 mm) had a 2.49 (95% CI: 1.36-4.56) times greater risk of stroke compared to the bottom quartile (≤6.80 mm) after adjustment was made for other variables. The C-R relationship further confirmed a positive association between CCA diameter and stroke prevalence in women. Moreover, a category-free net reclassification index (0.325; 95% CI: 0.173-0.476; P<0.001) and an integrated discrimination index (0.008; 95% CI: 0.004-0.012, P<0.001) showed improvement in predicting the probability of stroke from CCA diameter. However, no significant relationship between CCA diameter and prevalence of stroke was found in men.

CONCLUSIONS

The risk of stroke increased proportionally with the enlargement of the CCA diameter in women, supporting the sex-specific value of CCA diameter in optimizing the risk stratification of stroke.

Central Blood Pressure and Subclinical Atherosclerotic Risk in Young Hispanic American Women

Background

The incidence of younger women being hospitalized from cardiovascular disease (CVD) events is on the rise. Hispanic women are generally thought to have higher CVD risk factor burden than non-Hispanic White (NHW) women yet Hispanic Americans have lower mortality from CVD. Traditional measures of CVD may not accurately capture CVD risk in Hispanic Americans. Hence, the purpose of this study was to assess the impact of ethnicity on vascular reactivity and central hemodynamic load to gain insight into subclinical CVD risk in young women.

Methods

Brachial flow-mediated dilation (FMD), low-flow mediated constriction (L-FMC), carotid-femoral pulse wave velocity (cfPWV), and pulse wave analysis (from synthesized aortic pressure waveforms) were measured in 25 Hispanic women and 31 NHW women aged between 18-35 years. FMD and L-FMC were combined to provide an index of total vessel reactivity.

Results

NHW and Hispanic women did not differ in age or traditional CVD risk factors (P>.05 for all). Compared with NHW women, Hispanic women had greater vascular reactivity (8.7±4.1 vs 11.7±4.1 %, P=.011), lower central pulse pressure (28±5 vs 24±3 mm Hg, P=.001) and lower pressure from wave reflections (12±2 vs 10±1 mm Hg, P=.001). There were no differences in cfPWV between NHW women and Hispanic women (5.4±0.7 vs 5.3±0.7 m/s, P=.73).

Conclusion

Young Hispanic women have greater vascular reactivity and lower central pulsatile hemodynamic load compared with NHW women, suggesting lower subclinical CVD risk.

Morphometry of the Entire Internal Carotid Artery on CT Angiography

Background and Objectives: Knowledge of the internal carotid artery’s (ICA) morphometric features is influential in outlining surgical and minimally invasive procedures in the neurovascular field. Many studies have shown divisive numbers regarding the ICA’s caliber, with the measuring point of the artery sometimes differing. This study presents ICA dimensions based on computed tomography angiography in each of its seven segments as per Bouthillier’s classification, correlating vascular dimensions with anthropometric parameters. Materials and Methods: A thorough CT angiography analysis was performed on 70 patients with internal carotid vessels unaffected by atherosclerotic disease. The extracranial part of the ICA was measured in four locations—carotid bulb, post-bulbar dilation, at its cervical midpoint, and below its entrance into the carotid foramen. Single landmarks were used for measurements in the intracranial segments. ICA length was assessed in the neck region and also in the cranial cavity. Craniometric measurements were performed on sagittal and coronal CT reconstructions. Patient height was taken into consideration. Results: The largest ICA portion is near its origin in the carotid sinus area (7.59 ± 1.00 mm), with a steep decline in caliber following its extracranial course. Distal ICA presented values somewhat similar to its proximal intracranial segment diameters (4.67 ± 0.47 mm). Dimensions of the ICA in the intracranial segments start from a value of 4.53 ± 0.47 mm and decrease by approximately 40% when reaching the origin of the middle cerebral artery (2.71 ± 0.37 mm), showing a marked decrease in caliber after the emergence of the most critical collateral artery, the ophthalmic branch. The length of the ICA varies between genders, with the male ICA being about 10 mm longer in total length than female ICA; this difference is also correlated with patient height and skull dimensions. Conclusions: Both intra- and extracranial ICA have variable dimensions and length related to gender and anthropometric parameters, with no significant differences obtained concerning side or age.

Inner diameters of the normal carotid arteries measured using three-dimensional digital subtraction catheter angiography: a retrospective analysis

Purpose

To obtain normal ranges for the inner diameters of the carotid arteries.

Methods

This retrospective analysis included consecutive patients with disease-free carotid arteries who had undergone 3D-DSA at two hospitals in Nanning, Guangxi, between March 2013 and March 2018. Demographic and clinical characteristics, including Essen Stroke Risk Score (ESRS), were extracted from the medical records. The 3D-DSA data were used to calculate the inner diameters of the carotid arteries.

Results

The analysis included 1182 patients (837 males) aged 58.81 ± 11.02 years. The inner diameters of the proximal carotid sinus (CS), CS bulge, distal CS, and common carotid artery (CCA) were larger on the right than on the left (P < 0.05). The inner diameters of the proximal CS, CS bulge, distal CS, and CCA on both sides were larger for males than females (P < 0.05). The inner diameters of the proximal CS, CS bulge, and distal CS on both sides were smaller for patients aged > 65 years than for patients aged ≤ 55 years (P < 0.05). Right CCA inner diameter did not vary with age, whereas left CCA inner diameter was larger for patients aged > 55 years than for patients aged ≤ 45 years (P < 0.05). The inner diameters of the proximal CS, CS bulge, and distal CS on both sides were smaller for patients with ESRS ≥ 3 than those with ESRS < 3 (P < 0.05).

Conclusion

This study provides reference values for the internal diameters of normal carotid arteries. Carotid artery diameters varied with side, sex, and age.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02328-z.

Association of Flow Parameters and Diameter in the Common Carotid Artery with Impaired Glucose Metabolism

AIM

Diameter, intima-media thickness (IMT), and flow parameters, including resistance index (RI) and pulsatility index (PI), in the common carotid artery (CCA) are markers of arterial remodeling, atherosclerosis, and vascular resistance, respectively. We investigated the differences among these markers in association with plasma glucose level, serum insulin level, and insulin resistance in participants without cardiovascular disease.

METHODS

CCA parameters (including the CCA interadventitial diameter and mean IMT at the time of 75-g oral glucose tolerance testing) were assessed in 4218 participants. RI and PI were assessed in 3380 of these participants. To assess plasma glucose and serum immunoreactive insulin profiles during oral glucose tolerance testing, we used the total areas under the curves (AUCglu and AUCins, respectively). We used the homeostasis model assessment of insulin resistance (HOMA-IR) and the Matsuda index to assess insulin resistance. Insulin secretion was assessed with the HOMA-β.

RESULTS

AUCglu was significantly associated with CCA interadventitial diameter (β=0.048, P＜0.001), RI (β=0.144, P＜0.001), and PI (β=0.103, P＜0.001) but not with mean IMT. AUCins (β=-0.064, P＜0.001) and HOMA-β (β=-0.054, P＜0.001) were significantly and negatively associated with CCA interadventitial diameter, but not with mean IMT. Both HOMA-IR and Matsuda index were significantly associated with RI and PI.

CONCLUSIONS

These findings indicate that all CCA parameters except IMT are associated with impaired glucose metabolism in patients without cardiovascular disease.

Collateral circulation of the femoral and genicular systems in human lower limbs is highly uncommon

The descending branch of the lateral circumflex artery is a septocutaneous vessel that is vital for free and pedicle thigh flap transfer surgeries when repairing tissue defects. It also forms an anastomosis with the superior lateral genicular artery to create a collateral pathway for circumventing occlusions in the superficial femoral artery (SFA). Many anatomical texts and atlases imply the persistence of this anastomosis. However, previous studies indicate variability in the source of the arteries that form the anastomosis, and have reported cases where an anastomosis does not exist. We hypothesized that variations from the conventional accepted pattern can be predicted by comparisons of arterial diameters, and that unconventional anastomoses may be present to facilitate collateral circulation to the limb. Fifty-one limbs were dissected and analyzed to establish the source of the descending branch of the lateral circumflex artery, classify the types of anastomoses, and compare the diameters of the descending branch of the lateral circumflex artery, the SFA and the profunda femoris artery to the common femoral artery (CFA). Vessel diameters were normalized to the diameter of the CFA to allow comparison of limbs from both sexes and to minimize the effects of cadaver size on correlating vessel size to the presence or absence of collateral circuits. We report that 62.7% of limbs (32/51) had typical branching patterns; however, only 27.4% of limbs (14/51) had any anastomosis to connect the proximal and distal regions of the thigh. Importantly, the SFA had a wider relative diameter in limbs without anastomoses than in limbs that had normal anastomoses, perhaps precluding the formation of a collateral pathway. Overall, collateral circulation of the lower limb was highly uncommon, in contrast to information inferred from anatomical texts. This study suggests the need for more thorough procedures for determining viable anastomoses prior to thigh flap surgeries to ensure flap survival.

Ethnicity and Arterial Stiffness

Early vascular aging reflects increased arterial stiffness of central blood vessels at young chronological ages and powerfully predicts cardiovascular events and mortality, independent of routine brachial blood pressure and other risk factors. Since ethnic disparities exist in routine blood pressure, in hypertension and cardiovascular outcomes, this review evaluates major studies comparing arterial stiffness through the life course between different ethnic groups or races (which have no biological definition)-in children, adolescents, young, and middle-aged adults and the very elderly. Most report that compared with white European-origin samples, populations of black African descent have increased central arterial stiffness throughout different life stages, as well as a more rapid increase in arterial stiffness at young ages. Exceptions may include African Caribbean origin people in Europe. Differences in vascular structure and function are clearest, where obesity, socioeconomic, and psychosocial factors are most marked. Few studies evaluate a wider spectrum of ethnic groups or factors contributing to these ethnic disparities. Genetic effects are not obvious; maternal risk and intergenerational studies are scarce. Nevertheless, across all ethnic groups, for given levels of blood pressure and age, some people have stiffer central arteries than others. These individuals are most at risk of vascular events and mortality and, therefore, may benefit from early, as yet untested, preventive action and treatment.

Cardiovascular Disease Risk Factor Burden During the Menopause Transition and Late Midlife Subclinical Vascular Disease: Does Race/Ethnicity Matter?

Background The extent to which cardiovascular disease (CVD) risk factors across the menopause explain racial/ethnic differences in subclinical vascular disease in late midlife women is not well documented and was explored in a multi-ethnic cohort. Methods and Results Participants (n=1357; mean age 60 years) free of clinical CVD from the Study of Women's Health Across the Nation had common carotid artery intima-media thickness, interadventitial diameter, and carotid plaque presence assessed by ultrasonography on average 13.7 years after baseline visit. Early to late midlife time-averaged cumulative burden of traditional CVD risk factors calculated using serial measures from baseline to the ultrasound visit were generally less favorable in black and Hispanic women compared with white and Chinese women, including education and smoking status and time-averaged cumulative blood pressure, high-density lipoprotein cholesterol, and fasting insulin. Independent of these risk factors, BMI, and medications, common carotid artery intima-media thickness was thicker in black women, interadventitial diameter was wider in Chinese women, yet plaque presence was lower in black and Hispanic women compared with white women. CVD risk factor associations with subclinical vascular measures did not vary by race/ethnicity except for high-density lipoprotein cholesterol on common carotid artery intima-media thickness; an inverse association between high-density lipoprotein cholesterol and common carotid artery intima-media thickness was observed in Chinese and Hispanic but not in white or black women. Conclusions Race/ethnicity did not particularly moderate the association between traditional CVD risk factors measured across the menopause transition and late midlife subclinical vascular disease. Unmeasured socioeconomic, cultural, and nontraditional biological risk factors likely play a role in racial/ethnic differences in vascular health and merit further exploration.

Race and sex-based disparities associated with carotid endarterectomy in the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND AIMS

The indications for carotid endarterectomy (CEA) are well established. The aim of the current study was to investigate sex and race-based disparities in the incidence of CEA after adjusting for carotid artery stenosis risk factors.

METHODS

We conducted a prospective cohort analysis of 14,492 black and white participants in the Atherosclerosis Risk in Communities (ARIC) study without prevalent stroke at baseline (1987-1989). We used Kaplan-Meier curves and Cox proportional hazards models adjusting for sociodemographic, cardiovascular, and disease severity risk factors to quantify the associations of sex and race with incident CEA.

RESULTS

CEA was performed in 330 of 14,492 ARIC participants during a median of 27 years of follow-up [incidence rate 1.00 (95% CI 0.90-1.12) per 1000 persons-years]. The crude incidence of CEA varied significantly by sex [female vs. male: HR 0.60 (95% CI 0.48-0.74)] and race [black vs. white: HR 0.65 (95% CI 0.49-0.86)]. Adjustment for sociodemographic and cardiovascular risk factors, carotid intima-media thickness, and symptomatic status attenuated the association of sex with CEA [females vs. males HR 0.96 (0.76-1.22)], but black participants had a lower risk of incident CEA after adjustment [HR 0.68 (95% CI 0.49-0.95)].

CONCLUSIONS

We found significant variation in the incidence of CEA procedures based on race that was independent of traditional risk factors and carotid IMT. Whether this disparity is a reflection of differences in disease presentation or access to care deserves investigation.

Reference intervals and percentiles for carotid-femoral pulse wave velocity in a healthy population aged between 9 and 87 years

There is little information regarding age-related reference intervals (RIs) of carotid-femoral pulse wave velocity (cfPWV) for large healthy populations in South America. The aims of this study were to determine cfPWV RIs and percentiles in a cohort of healthy children, adolescents, and adults and to generate year-to-year percentile curves and body-height percentile curves for children and adolescents. cfPWV was measured in 1722 healthy participants with no cardiovascular risk factors (9-87 years, 60% men). First, RIs were evaluated for males and females through correlation and covariate analysis. Then, mean and standard deviation age-related equations were obtained for cfPWV using parametric regression methods based on fractional polynomials and age-specific (year-to-year) percentile curves that were defined using the standard normal distribution. Age-specific first, 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, 97.5th, and 99th percentile curves were calculated. Finally, height-related cfPWV percentile curves for children and adolescents (<21 years) were established. After adjusting for age and blood pressure differences with respect to females, males showed higher cfPWV levels (6.60 vs 6.45 m/s; P < .01). Thus, specific RIs for males and females were reported. The study provides the largest database to date concerning cfPWV in healthy people from Argentina. Specific RIs and percentiles of cfPWV are now available according to age and sex. Specific percentiles of cfPWV according to body height were reported for people younger than 21 years.

Carotid Intima-Media Thickness Is Associated With White Matter Hyperintensities: The Northern Manhattan Study

BACKGROUND AND PURPOSE

Brain white matter hyperintensities (WMH) have been associated with increased risk of stroke, cognitive decline, and dementia. WMH can be a manifestation of small vessel disease, although the total microvascular contribution to multifactorial WMH pathophysiology remains unknown. We hypothesized a possible relationship between carotid intima-media thickness (cIMT), an ultrasound imaging marker of subclinical vascular disease, and brain WMH in a multiethnic, elderly stroke-free community-based cohort.

METHODS

We evaluated the relationship between cIMT and WMH in the population-based Northern Manhattan Study, among individuals free of stroke. We used linear regression to examine the association of continuous measures of cIMT with quantitatively derived WMH volume, as a proportion of cranial volume, measured from fluid-attenuaded inversion recovery magnetic resonance imaging while adjusting for sociodemographics, lifestyle, and vascular risk factors.

RESULTS

In a cohort of 1229 participants (mean age, 71±9 years; 60% women, 15% White; 18% Black; 65% Hispanics), the mean cIMT was 0.71±0.08 mm and the median log-transformed WMH volume was 0.36 (interquartile range, 0.21-0.76). In a multivariable model, larger cIMT was significantly associated with greater WMH volume (β=0.046 per SD cIMT; P=0.04). Age and race/ethnicity were significant modifiers (P for age, 0.02; and P for race/ethnicity, 0.04). cIMT was associated with WMH volume in participants 70 years or older (β=0.088 per SD cIMT; P=0.01) and among Hispanics (β=0.084 per SD cIMT; P=0.003).

CONCLUSIONS

Larger cIMT was associated with greater burden of cerebral WM lesions independently of demographics and traditional vascular risk factors, particularly among elderly and Hispanic participants, who are at high risk for stroke and cognitive decline.

The effects of age on pulse wave velocity in untreated hypertension

Increased arterial stiffness is an important determinant of cardiovascular risk, able to predict morbidity and mortality, and closely associated with ageing and blood pressure. The aims of this study were: (1) To determine the age-dependent reference pulse wave velocity (PWV), and compare it with values from hypertensive patients, and (2) to evaluate the impact of isolated and untreated hypertension on arterial stiffness. A total of 1079 patients were enrolled and divided into a control group (NT) of asymptomatic normotensive patients and a group of asymptomatic hypertensive patients (HT). Blood pressure, carotid-femoral PWV, and body mass index were measured in each subject, whose blood was drawn for laboratory tests. Aortic mean PWV in the NT group was 6.85 ± 1.66 m/s, which increased linearly (R²  = 0.62; P < .05) with age. In patients over 50 years of age, PWV was significantly higher than in younger patients (8.35 vs 5.92 m/s, respectively, P < .001). This significant difference persisted when observing male and female patients separately. In the hypertensive group, mean PWV value was 8.04 ± 1.8 m/s (range 4.5-15.8 m/s) and increased (R²  = 0.243; P < .05) with age. The PWV increase in HT was significantly higher (0.93 m/s per decade, P < .001) than in NT (0.44 m/s per decade). Our study provides normal values of PVW per decade, and shows that these values increase with age, especially after 50 years of age, particularly in HT patients. This stiffness growth rate may be responsible for increased cardiovascular risk in both groups.

Relationship between carotid arterial properties and cerebral white matter hyperintensities

OBJECTIVE

Since arterial stiffness is a functional measure of arterial compliance and may be an important marker of cerebrovascular disease, we examined the association of carotid artery stiffness with white matter hyperintensity volume (WMHV) in a cross-sectional study of 1,166 stroke-free participants.

METHODS

Carotid beta stiffness index (STIFF) was assessed by M-mode ultrasound of the common carotid artery and calculated as the ratio of natural log of the difference between systolic and diastolic blood pressure over STRAIN, a ratio of the difference between carotid systolic and diastolic diameter (DD) divided by DD. WMHV was measured by fluid-attenuated inversion recovery MRI. The associations of STIFF, DD, and STRAIN with WMHV were examined using linear regression after adjusting for sociodemographic, lifestyle, and vascular risk factors.

RESULTS

In a fully adjusted model, larger carotid DD was significantly associated with greater log-WMHV (β = 0.09, p = 0.001). STIFF and STRAIN were not significantly associated with WMHV. In adjusted analyses stratified by race-ethnicity, STRAIN (β = -1.78, p = 0.002) and DD (β = 0.11, p = 0.001) were both associated with greater log-WMHV among Hispanic participants, but not among black or white participants.

CONCLUSIONS

Large carotid artery diameters are associated with greater burden of white matter hyperintensity (WMH) in this multiethnic population. The association between increased diameters, decreased STRAIN, and greater WMH burden is more pronounced among Hispanics. These associations suggest a potential important pathophysiologic role of extracranial large artery remodeling in the burden of WMH.

Association Between Long-Term Blood Pressure Variability and 10-Year Progression in Arterial Stiffness: The Multiethnic Study of Atherosclerosis

Experimental studies conducted on animal and human endothelium suggested that higher systolic blood pressure (SBP) variability reduces bioavailability of nitric oxide and increases vascular smooth muscle cell proliferation. These vascular wall changes could stiffen the arterial wall. Using data from the Multiethnic Study of Atherosclerosis, we investigated the association between long-term SBP variability and 10-year percent change in arterial stiffness among 1122 individuals (mean age 57 years, 46% males at baseline) who were not taking antihypertensive medications. Within-individual standard deviation, variability independent of the mean, and coefficient of variation of SBP across 5 visits were used to capture long-term SBP variability. Carotid arterial stiffness was measured using distensibility coefficient and Young's elastic modulus at baseline and after a mean of 9.5 years of follow-up (visit 5). In a multivariate linear regression model, individuals in the fifth quintile as compared with those in the first quintile of standard deviation, variability independent of the mean, and coefficient of variation of SBP had a 9.8% (95% confidence interval [CI] -17.0%, -2.7%), 6.4% (95% CI -13.2%, 0.4%), and 8.7% (95% CI -15.4%, -1.9%) higher decline in distensibility coefficient and a 27.5% (95% CI 15.8%, 39.3%), 25.8% (95% CI 14.7%, 36.9%), and 27.9% (95% CI 16.8%, 39.1%) higher progression in Young's elastic modulus, respectively, after 10 years of follow-up. Linear trends in the decline of distensibility coefficient and progression of Young's elastic modulus were observed across the quintiles of SBP variability indices. These findings suggest that higher long-term SBP variability may be a risk factor for arterial stiffness progression independent of mean BP.

Monocyte Chemoattractant Protein-1 and Large Artery Structure and Function in Young Individuals: The African-PREDICT Study

To better understand hypertension development, the authors determined whether monocyte chemoattractant protein-1 (MCP-1) is associated with arterial stiffness (pulse wave velocity [PWV]) and carotid intima-media wall thickness (cIMT) in a young apparently healthy black and white population (N=403, aged 20-30 years). Carotid-femoral PWV, central systolic blood pressure, and cIMT were measured, and MCP-1, reactive oxygen species, inflammatory markers (interleukin 6, tumor necrosis factor α), and endothelial activation (intercellular adhesion molecule, vascular cell adhesion molecule) were determined from blood samples. Although carotid-femoral PWV and cIMT were similar between blacks and whites, black men and women showed higher central systolic blood pressure, MCP-1, and reactive oxygen species than whites (all P<.05). In addition, black women had higher brachial blood pressure and interleukin 6 (all P<.001). A consistent positive association only in black women between cIMT and MCP-1 in multiple regression analyses was found (R²=0.151, β=0.248; P=.021). In this model, cIMT was also independently associated with vascular cell adhesion molecule (β=0.251; P=.022). The authors found elevated central systolic blood pressure and MCP-1 in young blacks, where cIMT was independently associated with MCP-1 in black women.

The relationship between carotid intima-media thickness and carotid plaque in the Northern Manhattan Study

OBJECTIVE

Carotid intima-media thickness (cIMT) and carotid plaque (CP) are proposed biomarkers of subclinical atherosclerosis associated with stroke risk. Whether cIMT and CP are distinct phenotypes or single traits at different stages of atherosclerotic development is unclear. We explored the relationship between these markers in the population-based Northern Manhattan Study.

METHODS

We used high-resolution ultrasound and validated imaging protocols to study the cross-sectional (N = 1788 stroke-free participants) and prospective relationship (N = 768 with follow-up scan; mean years between examinations = 3.5) between CP and cIMT measured in plaque-free areas.

RESULTS

The mean age was 66 ± 9 (40% male, 19% black, 17% white, 61% Hispanic). The mean baseline cIMT was 0.92 ± 0.09 mm, 0.94 ± 0.09 mm among the 58% with prevalent plaque, 0.90 ± 0.08 mm among the 42% without prevalent plaque (p < 0.0001). Each 0.1 mm increase in baseline cIMT was associated with a 1.72-fold increased odds of plaque presence (95%CI = 1.50-1.97), increased plaque thickness (effect on the median = 0.46 mm, p < 0.0001), and increased plaque area (effect on the median = 3.45 mm(2), p < 0.0001), adjusting for demographics and vascular risk factors. Elevated baseline cIMT was associated with an increased risk of new plaque in any location at follow-up, but after adjusting for demographics and vascular risk factors this association was no longer present. No association was observed in carotid segment-specific analyses.

CONCLUSION

Increased cIMT was associated with baseline prevalent plaque but did not predict incident plaque independent of other vascular risk factors. This finding suggests that increased cIMT is not an independent predictor of plaque development although these atherosclerotic phenotypes often coexist and share some common vascular determinants.

Compensatory intracranial arterial dilatation in extracranial carotid atherosclerosis: the Northern Manhattan study

BACKGROUND

There is a scarcity of data supporting the association between atherosclerosis and dolichoectasia in unbiased samples.

AIMS

To test the hypothesis that the association between dolichoectasia and extracranial carotid atherosclerosis depends on the degree of collateral circulation.

METHODS

The Northern Manhattan Study magnetic resonance imaging substudy consists of 1290 participants who remained stroke-free at the time of magnetic resonance imaging. Arterial diameters were collected in all participants with available magnetic resonance angiography. Dolichoectasia was defined as a head-size adjusted diameter >2 standard deviation for each artery. Carotid Doppler was used to evaluate for carotid atherosclerosis (carotid plaque, maximum plaque thickness and carotid intima media thickness).

RESULTS

We included 994 participants with available Doppler and magnetic resonance angiography data (mean age 63 years, 60% female). Any dolichoectasia was reported in 16% of participants, 54% had at least one carotid plaque and the mean carotid intima media thickness was 0·92 ± 0·09 mm. After adjusting for demographic and clinical characteristics, there was no association between markers of carotid atherosclerosis and dolichoectasia. However, stratifying by collaterals, it was observed that dolichoectasia was more likely in the anterior and posterior circulations when collaterals were available among participants with carotid atherosclerosis. These associations were confirmed by noting an increment in arterial diameters in the corresponding arteries ipsilateral and contralateral to each carotid as well as in the posterior circulation.

CONCLUSIONS

We did not find an association of extracranial carotid atherosclerosis with dolichoectasia. However, we found that dolichoectasia is more frequent when intracranial collaterals are available suggesting a compensatory process that needs further investigation.

Sex differences in predictors of longitudinal changes in carotid artery stiffness: the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

To identify sex differences in predictors of longitudinal changes in carotid arterial stiffness in a multiethnic cohort.

APPROACH AND RESULTS

Carotid artery distensibility coefficient (DC) and Young's elastic modulus (YEM) were measured in 2650 Multi-Ethnic Study of Atherosclerosis participants (45-84 years old and free of cardiovascular disease) at baseline and after a mean of 9.4 years. Predictors of changes in DC and YEM for each sex were evaluated using multivariable linear regression models. The 1236 men (46.6%) were 60.0 (SD, 9.3) years: 40% were white, 22% black, 16% Chinese, and 22% Hispanic. The 1414 (53.4%) women were 59.8 (9.4) years old with a similar race distribution. Despite similar rates of change in DC and YEM, predictors of changes in distensibility markers differed by sex. In men, Chinese (P=0.002) and black (P=0.003) race/ethnicity, systolic blood pressure (P=0.012), and diabetes mellitus (P=0.05) were associated with more rapidly decreasing DC (accelerated stiffening). Starting antihypertensive medication was associated with improved DC (P=0.03); stopping antihypertensives was associated with more rapid stiffening (increased YEM, P=0.05). In women, higher education was associated with slower stiffening (DC, P=0.041; YEM, P<0.001) as was use of lipid-lowering medication (P=0.03), whereas baseline use of antihypertensive medications (YEM, P=0.01) and systolic blood pressure (DC, P=0.02; P=0.04) predicted increasing stiffening in women.

CONCLUSIONS

Longitudinal changes in carotid artery stiffness are associated with systolic blood pressure and antihypertensive therapy in both sexes; however, race/ethnicity (in men) and level of education (in women) may have different contributions between the sexes.

Peripheral artery disease and non-coronary atherosclerosis in Hispanics: another paradox?

Hispanic Americans (HA) are a significant and increasing segment of the population who must be considered in future health planning. HA, compared to European Americans (EA), have a lower prevalence of coronary artery disease, but higher burden of cardiovascular disease risk factors. It remains unclear if this observation termed the 'Hispanic Paradox' also exists for vascular beds outside the heart. We present a review of the literature which suggests that this paradox may also exist for arteries in the extremities and neck.

Reference values of pulse wave velocity in healthy people from an urban and rural argentinean population

In medical practice the reference values of arterial stiffness came from multicenter registries obtained in Asia, USA, Australia and Europe. Pulse wave velocity (PWV) is the gold standard method for arterial stiffness quantification; however, in South America, there are few population-based studies. In this research PWV was measured in healthy asymptomatic and normotensive subjects without history of hypertension in first-degree relatives. Normal PWV and the 95% confidence intervals values were obtained in 780 subjects (39.8 ± 18.5 years) divided into 7 age groups (10–98 years). The mean PWV found was 6.84 m/s ± 1.65. PWV increases linearly with aging with a high degree of correlation (r² = 0.61; P < 0.05) with low dispersion in younger subjects. PWV progressively increases 6–8% with each decade of life; this tendency is more pronounced after 50 years. A significant increase of PWV over 50 years was demonstrated. This is the first population-based study from urban and rural people of Argentina that provides normal values of the PWV in healthy, normotensive subjects without family history of hypertension. Moreover, the age dependence of PWV values was confirmed.

The normal internal carotid artery: a computed tomography angiographic study

INTRODUCTION

Systematic computed tomography angiographic (CTA) studies investigating variation in internal carotid artery (ICA) luminal diameters (LDs) are scarce. Knowledge of the normal intra-individual LD variability would provide a cut-off value for detection of more subtle collapses. In addition, low intra-individual variability would allow using contralateral LD as a reference for estimation of stenosis degree in cases where ipsilateral measurement is hampered. Therefore, our aim was to investigate intra-individual LD variation of normal ICA.

METHODS

We retrospectively collected multidetector high-speed CTAs of 104 patients younger than 40 years who were considered not to have carotid pathology. We carried out independent measurements of the common carotid artery (CCA) and ICA LDs bilaterally from axial source images by two observers, analysing side-to-side LD differences from averaged double measurements with a paired t test.

RESULTS

We discovered no significant side-to-side LD differences. In the female group, the mean differences (mm) with 95% confidence intervals were 0.08 (0.00, 0.17) for CCA and 0.03 (-0.04, 0.11) for ICA, with ICA LD standard deviation of 0.4 mm. In the male group, these were: 0.06 (-0.04, 0.17), 0.02 (-0.07, 0.11) and 0.4 mm, respectively. We detected no ICA agenesis.

CONCLUSION

The intrinsic intra-individual variation of the LD of normal ICA is minimal. This uniformity may serve as the basis for detection of subtle grades of side-to-side variation caused by pathology.

Evaluation of the algorithm for automatic identification of the common carotid artery in ARTSENS

Arterial compliance (AC) is an indicator of the risk of cardiovascular diseases (CVDs) and it is generally estimated by B-mode ultrasound investigation. The number of sonologists in low- and middle-income countries is very disproportionate to the extent of CVD. To bridge this gap we are developing an image-free CVD risk screening tool-arterial stiffness evaluation for non-invasive screening (ARTSENS™) which can be operated with minimal training. ARTSENS uses a single element ultrasound transducer to investigate the wall dynamics of the common carotid artery (CCA) and subsequently measure the AC. Identification of the proximal and distal walls of the CCA, in the ultrasound frames, is an important step in the process of the measurement of AC. The image-free nature of ARTSENS creates some unique issues which necessitate the development of a new algorithm that can automatically identify the CCA from a sequence of A-mode radio-frequency (RF) frames. We have earlier presented the concept and preliminary results for an algorithm that employed clues from the relative positions and temporal motion of CCA walls, for identifying the CCA and finding the approximate wall positions. In this paper, we present the detailed algorithm and its extensive evaluation based on simulation and clinical studies. The algorithm identified the wall position correctly in more than 90% of all simulated datasets where the signal-to-noise ratio was greater than 3 dB. The algorithm was then tested extensively on RF data obtained from the CCA of 30 human volunteers, where it successfully located the arterial walls in more than 70% of all measurements. The algorithm could successfully reject frames where the CCA was not present thus assisting the operator to place the probe correctly in the image-free system, ARTSENS. It was demonstrated that the algorithm can be used in real-time with few trade-offs which do not affect the accuracy of CCA identification. A new method for depth range selection that leads to significant performance improvements has also been demonstrated.

Childhood family living arrangements and blood pressure in black men: the Howard University Family Study

Black men have higher blood pressure (BP) levels and consequently higher prevalence of hypertension compared with men from other ethnic groups in the United States. Socio-familial factors in childhood have been found to play an important role in hypertension, but few studies have examined this relationship among black men. We investigated whether childhood family living arrangements are independently associated with mean BP and hypertension in a cross-sectional sample of 515 unrelated black male participants aged ≥20 years enrolled in the Howard University Family Study between 2001 and 2008. Black men who lived with both parents compared with the reference group of men who never lived with both parents during their lifetime had lower systolic BP (-4.4 mm Hg [95% confidence interval {CI}, -7.84 to -0.96]), pulse pressure (-3.9 mm Hg [95% CI, -6.28 to -1.51]), and mean arterial BP (-2.0 mm Hg [95% CI, -4.44 to 0.51]). This protective effect was more pronounced among men who lived with both parents for 1 to 12 years of their lives; they had decreased systolic BP (-6.5 mm Hg [95% CI, -10.99 to -1.95]), pulse pressure (-5.4 mm Hg [95% CI, -8.48 to -2.28]), mean arterial pressure (-3.3 mm Hg [95% CI, -6.56 to 0.00]), and a 46% decreased odds of developing hypertension (odds ratio=0.54; 95% CI, 0.30 to 0.99). No statistically significant associations were found for diastolic BP. These results provide preliminary evidence that childhood family structure exerts a long-term influence on BP among black men.

An improved method for detection of carotid walls in ARTSENS

We have been developing a fully automated ultrasound based imageless system to facilitate mass screening of patients for future risk of cardiovascular diseases. The device shall enable a general medical practitioner to non-invasively measure the local arterial stiffness of common carotid artery (CCA) and has been acronymed ARTerial Stiffness Evaluation for Non-invasive Screening (ARTSENS™). Complete automation of the system requires providing assistance in placement of probe over the CCA location and automatic identification of approximate location of proximal wall (PW) and distal wall (DW) of the CCA. In this paper we propose a method based on temporal motion of PW and DW over successive A-Mode frames to locate the CCA. We evaluated the performance of the algorithm with data obtained from CCA of 30 subjects. It could correctly identify the CCA in more than 70 % of trials. We also propose a method for preprocessing the frames by using the transmitted pulse wavelet. This improved the detection rate significantly. False positives were always less than 6% of total detections.

Automatic measurement of lumen diameter of carotid artery in A-Mode ultrasound

Accurate measurement of lumen diameter is essential for correct estimation of arterial compliance. We have been developing a new non-invasive arterial compliance measurement tool using a single element ultrasound transceiver. In this paper we propose a new method for measurement of lumen diameter from single line of Radio-Frequency Signal (RF) obtained from the common carotid artery (CCA). The method is free from fixed thresholds and uses shape fitting to get objective measurement. The accuracy of the algorithm was found to be better than 5 % for software simulated and phantom arteries and better than 10 % in case of data obtained from CCA of human volunteers.