Abdominal aortic diameter and vascular atherosclerosis: the Multi-Ethnic Study of Atherosclerosis

Abdominal aortic calcium and geometry in patients with essential hypertension

PURPOSE

Abdominal aorta calcium (AAC) burden and dilatation are associated with an increased risk of mortality. The purpose of this study was to investigate determinants of AAC and abdominal aorta size in patients with essential hypertension.

MATERIALS AND METHODS

Patients with uncomplicated essential hypertension who had undergone non-enhanced abdominal CT to rule out secondary hypertension in addition to biological test were recruited between 2010 and 2018. A semi-automatic system was designed to estimate the aortic size (diameter, length, volume) and quantify the AAC from mesenteric artery to bifurcation using the Agatston score. Determinants of aortic size and those related to AAC were searched for using uni- and multivariables analyses.

RESULTS

Among 293 randomly selected patients with hypertension (age 52 ± 11 [SD] years) included, 23% had resistant hypertension. Mean abdominal aorta diameter was 20.1 ± 2.1 (SD) mm. Eight (3%) patients had abdominal aorta aneurysm ≥ 30 mm and 58 (20%) had dilated abdominal aorta ≥ 27 mm. Median AAC score was 38 and calcifications were detected in the infra- and supra-renal abdominal aortic portions in 59% and 26% of the patients, respectively. After adjustment for age, male sex and body surface area, abdominal aorta diameter was positively associated with diastolic blood pressure (P = 0.0019). Smoking was the single variable associated with calcified abdominal aorta (P < 0.001) after adjustment for cofactors. In patients with calcifications of abdominal aorta, the score increased with smoking history (P < 0.001), statins treatment (P < 0.01), greater number of anti-hypertensive drugs (P < 0.01), larger abdominal aorta (P < 0.05) and greater systolic blood pressure (P < 0.05). Patients with resistant hypertension had more AAC in the supra-renal abdominal aorta portion than those without resistant hypertension (P < 0.01).

CONCLUSION

In patients with essential hypertension, abdominal aorta dilation is related with diastolic blood pressure while AAC is associated with smoking history and resistant hypertension when located to the supra-renal abdominal aorta portion.

Effect of EVAR on International Ruptured AAA Mortality-Sex and Geographic Disparities

Background: We sought to investigate the differential impact of EVAR (endovascular aneurysm repair) vis-à-vis OSR (open surgical repair) on ruptured AAA (abdominal aortic aneurysm) mortality by sex and geographically. Methods: We performed a retrospective study of administrative data on EVAR from state statistical agencies, vascular registries, and academic publications, as well as ruptured AAA mortality rates from the World Health Organization for 14 14 states across Australasia, East Asia, Europe, and North America. Results: Between 2011-2016, the proportion of treatment of ruptured AAAs by EVAR increased from 26.1 to 43.8 percent among females, and from 25.7 to 41.2 percent among males, and age-adjusted ruptured AAA mortality rates fell from 12.62 to 9.50 per million among females, and from 34.14 to 26.54 per million among males. The association of EVAR with reduced mortality was more than three times larger (2.2 vis-à-vis 0.6 percent of prevalence per 10 percentage point increase in EVAR) among females than males. The association of EVAR with reduced mortality was substantially larger (1.7 vis-à-vis 1.1 percent of prevalence per 10 percentage point increase in EVAR) among East Asian states than European+ states. Conclusions: The increasing adoption of EVAR coincided with a decrease in ruptured AAA mortality. The relationship between EVAR and mortality was more pronounced among females than males, and in East Asian than European+ states. Sex and ethnic heterogeneity should be further investigated.

Evolution and outcomes of aortic dilations in giant cell arteritis

OBJECTIVES

To identify factors associated with the progression of giant cell arteritis (GCA)-related or associated aortic dilations.

METHODS

In this retrospective study, 47 GCA patients with aortic dilation were longitudinally analyzed. Each patient underwent ≥2 imaging scans of the aorta during the follow-up. Three progression statuses of aortic dilations were distinguished: fast-progressive (FP) defined by a progression of the aortic diameter ≥5 mm/year or ≥1 cm/2 years, slow progressive (SP) by a progression of the aortic diameter >1 mm during the follow-up, and not progressive (NP) when aortic diameter remained stable.

RESULTS

Among the 47 patients with aortic dilation, the thoracic section was involved in 87 % of patients. Within a total follow-up of 89 [6-272] months, we identified 13 (28 %) patients with FP dilations, and 16 (34 %) and 18 (38 %) patients with SP and NP dilations, respectively. No differences regarding baseline characteristics, cardiovascular risk factors or treatments were observed among the 3 groups. However, FP patients more frequently showed atheromatous disease (p = 0.04), with a more frequent use of statins (p = 0.04) and antiplatelet agents (p = 0.02). Among the 27 (57 %) patients with aortitis, aortic dilation developed on an inflammatory segment in 23 (85 %). Among the FP patients who underwent aortic surgery with available histology (n = 3), all presented active vasculitis.

CONCLUSION

This study suggests that aortic inflammation, as well as atheromatous disease, might participate in the fast progression of aortic dilation in GCA.

Aortic aneurysms and markers of platelet activation, hemostasis, and endothelial disruption in people living with HIV

Introduction

People living with HIV (PLWH) are at twice the risk of developing cardiovascular diseases and have more than four times higher odds of aortic aneurysm (AA) than the uninfected population. However, biomarkers of AA in PLWH are yet to be discovered. We aimed to investigate whether circulating biomarkers reflecting platelet activation, hemostasis and endothelial disruption, i.e. sCD40L, D-dimer, syndecan-1, and thrombomodulin, were associated with AA in PLWH.

Methods

Five hundred seventy one PLWH from the Copenhagen Comorbidity in HIV Infection (COCOMO) study ≥40 years of age with an available contrast-enhanced CT scan as well as available biomarker analyses were included. The biomarkers were analyzed on thawed plasma. For each biomarker, we defined high level as a concentration in the upper quartile and low level as a concentration below the upper quartile. For D-dimer, the cut-off was defined as the lower limit of detection. Using unadjusted and adjusted logistic and linear regression models, we analyzed associations between AA and sCD40L, D-dimer, syndecan-1, and thrombomodulin, respectively in PLWH.

Results

PLWH had median (IQR) age 52 years (47-60), 88% were male, median (IQR) time since HIV diagnosis was 15 years (8-23), and 565 (99%) were currently on antiretroviral treatment. High level of sCD40L was associated with lower odds of AA in both unadjusted (odds ratio, OR, 0.23 (95% CI 0.07-0.77; P=0.017)) and adjusted models (adjusted OR, aOR, 0.23 (95% CI 0.07-0.78; P=0.019)). Detectable level of D-dimer was associated with higher odds of AA in both unadjusted (OR 2.76 (95% CI 1.34-5.67; P=0.006)) and adjusted models (aOR 2.22 (95% CI 1.02-4.85; P=0.045)).

Conclusions

SCD40L was associated with lower odds of AA whereas D-dimer was independently associated with higher odds of AA in PLWH. This calls for further investigations into specific biomarkers to aid early diagnosis of AA in PLWH.

Distribution, Determinants and Normal Reference Values of Aortic Arch Width: Thoracic Aortic Geometry in the Framingham Heart Study

Study Objective

Aortic arch geometry changes with age, including an increase in aortic arch width (AAW). High AAW is a predictor of incident adverse cardiovascular disease (CVD) events, but its distribution and determinants are unknown. We hypothesized that traditional CVD risk factors, in addition to age, are associated with increased AAW in community-dwelling adults.

Study Design

Framingham Offspring and Third Generation cohort participants (N=3026, 52% Men) underwent thoracic multidetector computed tomography (MDCT). A referent group (733M, 738W) free of clinical CVD, hypertension, dyslipidemia, smoking, and diabetes was used to generate sex and 10-year age-group specific upper 90th percentile (P90) cut-points for AAW. AAW was measured as the distance between the cross-sectional centroids of the ascending and descending thoracic aorta. Multivariable logistic regression models were used to identify clinical correlates of high AAW (≥referent P90) in the overall study group.

Results

Among referent participants, AAW increased with greater age-group, p for trend <0.0001 in each sex. Overall and within each age group, AAW was greater in men than women, p<0.0001 all comparisons. Across all participants, high AAW was associated with greater age (odds ratio, OR=1.34/10y; 95% confidence interval 1.20 - 1.50), body surface area (OR=1.97/SD; 1.62 - 2.40), diastolic blood pressure (OR=1.59/10mmHg; 1.40 - 1.81), pack-years smoked (OR=1.07; 1.02 - 1.13), and prevalent CVD (OR=1.64; 1.08 - 2.49).

Conclusion

AAW increases with greater age, body size, diastolic blood pressure and burden of smoking. High AAW (≥referent P90) is also associated with prevalent (clinically apparent) CVD. AAW is often seen on and easily measured from tomographic thoracic images and has prognostic value.

Normal Infrarenal Aortic Diameter in Men and Women in a Mediterranean Area

BACKGROUND

Infrarenal aortic diameter (AD) values currently considered normal are based on measurements from epidemiologic studies performed over 20 years ago. Knowledge of expected normal AD is important for understanding the relevance of abdominal aortic dilatation. The aim of this study was to define contemporary reference values for normal infrarenal AD and build a predictive model based on individual features.

METHODS

A cross-sectional study of participants in a population-based screening program for abdominal aortic aneurysm (AAA) was performed in a healthcare district with 400,000 inhabitants. Men and women aged 65 years were invited to participate. Cardiovascular (CV) risk factors, family history of AAA, personal history of other aneurysms, CV disease, and anthropometric parameters were evaluated. The largest anteroposterior inner-inner diameter of the infrarenal aorta was measured by ultrasound. Multiple linear regressions were used to determine independent predictors of AD. The best-fit model was obtained by randomly selecting 70% of the sample and validating the results in the remaining 30%.

RESULTS

A total of 4,730 people (2,089 men and 2,641 women) were invited. The participation rate was 50.4% for men and 44.0% for women. Mean AD (standard deviation, SD) was 16.51 (3.2) mm in the overall group, 17.91 (3.51) mm in men, and 15.25 (2.32) mm in women (P < 0.001). Male sex (P < 0.001), body surface area (P < 0.001), smoking habit (P = 0.012), and history of arterial aneurysms (P = 0.013) were independently associated with increased AD. Dyslipidemia was associated with decreased AD (P < 0.001). The findings were used to build a model for predicting AD based on individual characteristics.

CONCLUSIONS

ADs in our study population are smaller than those described in classic epidemiological studies. Men have a significantly larger diameter than women and the strongest predictor of increased AD is body surface area. A greater understanding of factors associated with AD will help predict expected sizes in individual members of the population.

Prevalence and Risk Factors of Abdominal Aortic Aneurysms Detected with Ultrasound in Korea and Belgium

The objective was to investigate the prevalence of abdominal aortic aneurysms (AAAs) and the diameters of the aorta and common iliac arteries (CIAs) in a Korean cohort and secondly to analyze the differences in aortic diameter by comparison with a European cohort. The Korean cohort included participants ≥ 50 years who consented to AAA screening and data were analysed retrospectively. Aortic and common iliac diameters were measured using the outer-to-outer diameter method and prevalence rates were calculated. Common risk factors such as smoking, body mass index, pulmonary disease, hypertension, diabetes, hyperlipidaemia, ischaemic heart disease, and cerebrovascular disease were reported in association with AAA occurrence and AAA development. The aortic diameters were then compared with those in a Belgian cohort of 2487 participants identified in the Liège AAA Screening Program. An aortic size index (ASI) was also calculated to account for the potential size differences in the Belgian and Korean populations. A total of 3124 Korean participants were examined using ultrasound. The prevalence of AAAs in this cohort was 0.7%. The combined prevalence of subaneurysmal dilatation and AAA was 1.5%. The prevalence in male smokers older than 65 years was 2.7% (19/715). The mean infrarenal aortic diameter was 17.3 ± 3.1 mm in men and 15.7 ± 2.7 mm in women; the corresponding values in Belgian participants were 19.4 ± 3.0 mm in men and 17.9 ± 2.4 mm in women. The median aortic size index was 0.99 (interquartile range 0.88-1.12). The mean infrarenal aortic diameter was significantly smaller in the Korean cohort than in the Belgian cohort. Considering the observed prevalence of AAAs in different age groups, the age groups which would contribute to most cases was male persons above 66 years in both cohorts.

Preliminary Understanding of Abdominal Aortic and Common Iliac Artery Diameters on Abdominal CT in Ethiopian Adults: A Facility-Based Cross-Sectional Study

BACKGROUND

Mean aortic and common iliac artery diameters are the best indicators for the diagnosis of aortic and iliac ectasia and aneurysm, as well as the appropriate selection of angiographic catheter size and grafts for endovascular procedures. Currently, there is a lack of evidence regarding the normal abdominal aortic and common iliac artery diameters in Ethiopian adults. This study aimed to assess the mean diameter and associated factors of the abdominal aorta and common iliac arteries on abdominal CT scans of Ethiopian adults visiting Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia.

METHODS

Institution-based prospective cross-sectional study was conducted. A convenience sampling method was employed. Data were collected from consecutive eligible adults who came for abdominal CT scans during the study period, using interviewer-administered structured questionnaires. The data was cleaned and analyzed using SPSS version 22. Student t-test and Pearson correlation were used to perform statistical analysis and the results were presented using tables and figures.

RESULTS

There were a total of 136 study participants of whom eighty-one(59.6%) were females and fifty-five (40.4%) were males. The mean age was 48.5 ± 13 with a range of 23 to77 years. The mean transverse diameter of the aorta at the aortic hiatus (T12)level was 2.30 ± 0.25cm in males and 2.03±0.19cm in females. The mean transverse diameter of the suprarenal aorta was 2.04 ± 0.21cm in males and 1.83 ± 0.21 cm in females while the infrarenal one was 1.77 ± 0.16cm in males and 1.54 ± 0.15cm in females. Participants who are male and older with large body Surface Area were found to have relatively larger aortic and iliac diameters.

CONCLUSION

In this study, the mean diameter of the aorta and common iliac artery was significantly associated with age, sex, and BSA.

Ultrasonographic Study of the Effects of Essential Hypertension on the Luminal Diameter and Doppler Velocimetric Indices of the Abdominal Aorta in Adults

OBJECTIVE

To investigate the effects of essential hypertension on the luminal diameter (caliber) and Doppler velocimetric indices of the abdominal aorta (AA) in adult patients with systemic hypertension.

MATERIALS AND METHODS

This was a prospective descriptive comparative study of 254 participants (127 with essential hypertension and 127 age/sex-matched controls). Their anthropometric parameters, fasting blood pressure, lipid profile, fasting blood sugar, and triplex sonography of the suprarenal and infrarenal abdominal aorta (Peak systolic velocity, PSV; End-diastolic velocity, EDV; Resistive Index, RI; and luminal diameter) were evaluated.

RESULTS

The mean age of the male subjects was 64.02 ± 10.02 years, while the mean age of the male controls was 63.14 ± 10.52 years (P > 0.05). The mean age of female subjects was 61.23 ± 10.09 years, while the mean age of the female controls was 61.76 ± 10.26 years (P > 0.05). The age group 60 - 69 years had the highest number of subjects and controls. The mean duration of hypertension in the subjects was 12.5 ± 5.2 years. The suprarenal and infrarenal abdominal aortic diameters (AAD) were higher in males than age-matched female counterparts. AAD increased with age mostly in hypertensive male subjects. PSV (in males) and RI (in both sexes) were elevated in hypertensive subjects compared to controls, while EDV (in both sexes) was significantly lower in subjects than controls. Multivariate linear regression showed that age and diastolic blood pressure were significant independent predictors for both suprarenal and infrarenal AADs.

CONCLUSION

Systemic hypertension causes structural and hemodynamic changes in the abdominal aorta which are detectable on triplex sonography.

Potential influencing factors of aortic diameter at specific segments in population with cardiovascular risk

Background

Aortic diameter is a critical parameter for the diagnosis of aortic dilated diseases. Aortic dilation has some common risk factors with cardiovascular diseases. This study aimed to investigate potential influence of traditional cardiovascular risk factors and the measures of subclinical atherosclerosis on aortic diameter of specific segments among adults.

Methods

Four hundred and eight patients with cardiovascular risk factors were prospectively recruited in the observational study. Comprehensive transthoracic M-mode, 2-dimensional Doppler echocardiographic studies were performed using commercial and clinical diagnostic ultrasonography techniques. The aortic dimensions were assessed at different levels: (1) the annulus, (2) the mid-point of the sinuses of Valsalva, (3) the sinotubular junction, (4) the ascending aorta at the level of its largest diameter, (5) the transverse arch (including proximal arch, mid arch, distal arch), (6) the descending aorta posterior to the left atrium, and (7) the abdominal aorta just distal to the origin of the renal arteries. Multivariable linear regression analysis was used for evaluating aortic diameter-related risk factors, including common cardiovascular risk factors, co-morbidities, subclinical atherosclerosis, lipid profile, and hematological parameters.

Results

Significant univariate relations were found between aortic diameter of different levels and most traditional cardiovascular risk factors. Carotid intima-media thickness was significantly correlated with diameter of descending and abdominal aorta. Multivariate linear regression showed potential effects of age, sex, body surface area and some other cardiovascular risk factors on aortic diameter enlargement. Among them, high-density lipoprotein cholesterol had a significantly positive effect on the diameter of ascending and abdominal aorta. Diastolic blood pressure was observed for the positive associations with diameters of five thoracic aortic segments, while systolic blood pressure was only independently related to mid arch diameter.

Conclusion

Aortic segmental diameters were associated with diastolic blood pressure, high-density lipoprotein cholesterol, atherosclerosis diseases and other traditional cardiovascular risk factors, and some determinants still need to be clarified for a better understanding of aortic dilation diseases.

Aortic enlargement and coronary artery calcification in a general population cohort

AIMS

The role of atherosclerosis in the pathogenesis of aortic enlargement is uncertain. We aimed to evaluate the relationship between the diameters of the ascending, descending and abdominal aorta, and coronary artery calcification.

METHODS AND RESULTS

Individuals in the Copenhagen General Population Study underwent thoracic and abdominal computed tomography. Maximal aortic diameters were measured in each aortic segment and coronary artery calcium scores (CACS) were calculated. Participants were stratified into five predefined groups according to CACSs and compared to aortic dimensions. The relation between aortic diameter and CACS was adjusted for risk factors for aortic dilatation in a multivariable model. A total of 2678 eligible individuals were included. In all segments of the aorta, aortic diameter was associated to CACSs, with mean increases in aortic diameters ranging from 0.7 to 3.5 mm in individuals with calcified coronary arteries compared to non-calcified subjects (P-value < 0.001). After correction for risk factors, individuals with CACS above 400 had larger ascending, descending and abdominal aortic diameter than the non-calcified reference group (P-value < 0.01).

CONCLUSION

Enlarged thoracic and abdominal aortic vascular segments are associated with co-existing coronary artery calcification in the general population.

Relationship between the abdominal aortic diameter and carotid atherosclerosis in middle-aged patients without established atherosclerotic cardiovascular diseases

BACKGROUND

The purpose of our research was to study the relationship between the diameter of abdominal aorta (AA) and subclinical atherosclerosis in patients without established atherosclerotic cardiovascular diseases (ASCD) in the absence of pathological enlargement of AA.

METHODS

The study included 136 patients (52.9% male, 47.1% female), median age was 51.0 (45.5; 58.0) years. The maximum diameter of AA was measured in the infrarenal region at a level between the place of origin of the lower renal artery and bifurcation in cross section. Measurement of the anteroposterior diameter of AA was carried out from the outer-to-outer edge (OTO). Also, we determined the Aortic Size Index (ASI) with respect to body surface area (BSA), using the values of BSA obtained by five different formulas validated for use in clinical practice. All patients underwent carotid duplex ultrasound scanning with assessment of degree of carotid stenosis (according to ECST criteria).

RESULTS

An increase in the anteroposterior diameter of AA was directly correlated with maximum stenosis of carotid arteries (r=0.186; P=0.030). According to the results of a logistic regression analysis an increase in the diameter of AA by 1 mm was associated with an increase in the relative risk of carotid stenosis ≥50% by 1.37 times (95% CI: 1.01-1.85; P=0.041) after adjustment. Thus, an increase in diameter of AA of more than 1.75 cm with a sensitivity of 71.4% and a specificity of 73.0% made it possible to predict the presence of stenosis of the carotid arteries ≥50%. An increase in ASI<inf>Boyd</inf> (BSA was calculated using Boyd's formula) of more than 0.84 allowed predicting the presence of stenosis of the carotid arteries ≥50% with a sensitivity of 85.7% and a specificity of 65.6%.

CONCLUSIONS

In middle-aged patients without established ASCD, the diameter of AA and ASI directly correlated with the degree of carotid stenosis (according to ECST criteria). The diameter of AA and ASI demonstrated good sensitivity and specificity for the presence of asymptomatic carotid stenosis of ≥50%.

Diameter and growth rate of the thoracic aorta-analysis based on serial computed tomography scans

Background

Although there are studies on the growth of thoracic aorta in the general population, research based on serial computed tomography scan is rare. We investigated the influence of patient age and anthropometric variables on the size and growth rate of the thoracic aorta in the general hospital population.

Methods

Data on 2,353 adults [2003–2014] who underwent ≥2 serial computed tomography examinations with at least a 6-year interval were analyzed. There were 1,444 men (61%), and the mean age was 58±12 years (range, 17–92 years). Thoracic aortic diameters were measured at 5 levels (the sinus of Valsalva, ascending aorta, aortic arch, and proximal and distal descending thoracic aorta) in the first and last computed tomography scans taken at a median interval of 7.0 years (interquartile range: 6.4–8.0).

Results

The mean aorta diameters were 34.9±4.7, 34.1±4.6, 28.0±3.8, 24.8±3.4, and 23.8±3.3 mm in the sinus of Valsalva, ascending aorta, arch, and proximal and distal descending thoracic aorta, respectively. The initial aorta diameter was larger in older subjects and in those with a larger body surface area (BSA). Female subjects had a significantly larger indexed diameter (diameter/BSA) than male subjects (P<0.001 at all five levels). In all thoracic aorta levels, the growth rate was the highest in subjects in their 40s, and the growth rate negatively correlated with the initial indexed diameter (P<0.001 at all five levels). In 40–50% of the subjects, thoracic aorta size remained stable during the interval.

Conclusions

The thoracic aorta dilated with aging and was larger in subjects with a larger body size. Sex differences in the gross aortic diameter might be related to differences in body size. The growth of the thoracic aorta was faster in younger subjects with a smaller indexed diameter.

Association Between Cardiovascular Risk Factors and the Diameter of the Thoracic Aorta in an Asymptomatic Population in the Central Appalachian Region

BACKGROUND

Effects of cardiovascular (CV) risk factors on the diameter of the thoracic aorta have not been fully studied. This study examined the associations between CV risk factors and diameter of thoracic aorta.

MATERIALS AND METHODS

Study population comprised of 1273 asymptomatic adults aged ≥18 years from Central Appalachia region of the United States who participated in a coronary artery screening between January 2014 and December 2016. Descriptive statistics and multiple linear regression analyses were performed to examine associations between multiple CV risk factors and diameters of the thoracic aorta.

RESULTS

Mean (±SD) age of participants was 57.9±9.7 years; that of body mass index (BMI) was 29.4±5.9. The mean aortic sinus, ascending aorta, and descending aorta diameter were 34.1±4.4 mm, 33.8±4.4 mm, and 26.0±3.6 mm, respectively. Increasing age, being male, and having a higher BMI were associated with wider aortic sinus, ascending aorta, and descending aorta diameters. Hypertension (p < 0.05) and obesity (p < 0.0001) were significantly associated with wider diameter for all measured aortic diameters. Participants with diabetes had wider descending aorta compared to those without (26.6±3.9 mm vs. 25.9±3.5 mm, P = 0.012). Participants who had ever smoked a cigarette had significantly wider descending aorta diameter compared to never smokers (26.3±3.6 mm vs. 25.9±3.5 mm, p = 0.031).

CONCLUSIONS

The study results suggest that decreasing BMI and management of CV risk factors such as hypertension and modifying behavioral risk factors such as smoking are likely to be emphasized in order to decrease the rate of aortic dilatation and subsequent aortic dissection, if aortic dilatation is detected during a CT scan.

A Comparative Study of Biomechanical and Geometrical Attributes of Abdominal Aortic Aneurysms in the Asian and Caucasian Populations

In this work, we provide a quantitative assessment of the biomechanical and geometric features that characterize abdominal aortic aneurysm (AAA) models generated from 19 Asian and 19 Caucasian diameter-matched AAA patients. 3D patient-specific finite element models were generated and used to compute peak wall stress (PWS), 99th percentile wall stress (99th WS), and spatially averaged wall stress (AWS) for each AAA. In addition, 51 global geometric indices were calculated, which quantify the wall thickness, shape, and curvature of each AAA. The indices were correlated with 99th WS (the only biomechanical metric that exhibited significant association with geometric indices) using Spearman's correlation and subsequently with multivariate linear regression using backward elimination. For the Asian AAA group, 99th WS was highly correlated (R2 = 0.77) with three geometric indices, namely tortuosity, intraluminal thrombus volume, and area-averaged Gaussian curvature. Similarly, 99th WS in the Caucasian AAA group was highly correlated (R2 = 0.87) with six geometric indices, namely maximum AAA diameter, distal neck diameter, diameter-height ratio, minimum wall thickness variance, mode of the wall thickness variance, and area-averaged Gaussian curvature. Significant differences were found between the two groups for ten geometric indices; however, no differences were found for any of their respective biomechanical attributes. Assuming maximum AAA diameter as the most predictive metric for wall stress was found to be imprecise: 24% and 28% accuracy for the Asian and Caucasian groups, respectively. This investigation reveals that geometric indices other than maximum AAA diameter can serve as predictors of wall stress, and potentially for assessment of aneurysm rupture risk, in the Asian and Caucasian AAA populations.

A Comparison of Aortoiliac Disease between Eastern and Western Countries

A variety of diseases are known to develop in the aortoiliac segment; these include abdominal aortic aneurysm (AAA) and aortoiliac occlusive disease. This review summarizes several differences of aortoiliac diseases between eastern and western populations. The prevalence of AAA was higher in western countries (4.57% to 19%) than in eastern countries (0.89% to 4.9%). Greater aortic bifurcation angles were observed in the eastern population, while longer common iliac arteries and aneurysm necks were found in the western population with AAA. However, the angle of the aneurysm was found to be more acute in patients from western countries. Several differences were found between patients from western countries and those from eastern countries regarding the diseases that occur in the aortoiliac segment and their anatomical characteristics. Therefore, different approaches to the treatment of aortoiliac diseases in these two groups should be considered.

The population prevalence of undetected abdominal aortic aneurysm in New Zealand Māori

BACKGROUND

The prevalence of abdominal aortic aneurysm (AAA) in Polynesian populations such as the New Zealand Māori has not been characterized. We measured this in a large population-based sample.

METHODS

A cross-sectional population-based prevalence study was conducted as part of an AAA screening pilot; 2467 Māori men aged 54 to 74 years and 1526 women aged 65 to 74 years registered with a primary care practice in Auckland (New Zealand) were invited to be screened by abdominal ultrasound between June 2016 and March 2018. Patients with pre-existing AAA disease and those with terminal conditions or circumstances that would make them unlikely to benefit from screening were excluded. The prevalence rate of AAA in Māori women was calculated with a cutoff definition of 27 mm as well as with the normal 30-mm definition (used in men). A log-binomial regression model estimated the prevalence rate at exactly 65 years for the purpose of comparison with screened populations in the United Kingdom.

RESULTS

The crude prevalence rate of undiagnosed AAA in Māori men aged 60 to 74 years was 3.6%. In women, it was 1.7% at the 30-mm threshold and 2.3% at 27 mm. The prevalence rate at exactly 65 years of age was calculated from the log-binomial regression model to be 2.7% (confidence interval [CI], 2.0%-3.8%) in men, 0.9% (CI, 0.4%-2.2%) in women at the 30-mm threshold, and 1.5% (CI, 0.7%-3.0%) in women at the 27-mm threshold. Among smokers, the crude prevalence rates were 7.5% (CI, 4.9%-11.5%) in men and 6.9% (CI, 4.1%-11.5%) in women (30 mm+).

CONCLUSIONS

The prevalence of undiagnosed AAA in New Zealand Māori men is considerably higher than in screened populations of equivalent age in the United Kingdom and Sweden. Prevalence rates in New Zealand Māori women are close to those of screened British men. New Zealand should consider implementing a population-based screening program for Māori men and conduct further research into the health impact of screening Māori women.

No association between the abdominal aorta diameter and cervicocephalic atherosclerosis-Potential non-atherosclerotic origins of abdominal aorta aneurysms?

The atherosclerotic origin of abdominal aorta (AA) aneurysms is controversial. Using the Atahualpa Project Cohort, we aimed to assess the relationship between the AA diameter and two surrogates of cervicocephalic atherosclerosis, including the carotid intima-media thickness (cIMT) and the presence of carotid siphon calcifications (CSC). Atahualpa residents aged ≥60 years undergoing ultrasound examinations of the abdominal aorta and the carotid arteries (to calculate the AA diameter and the cIMT), and head CT (to assess CSC severity) were included. Associations between AA diameter and cIMT and CSC severity were assessed by generalized linear models, after adjusting for relevant confounders. Of 256 participants, 64 (25%) had an increased cIMT and 85 (33%) had high calcium content in the carotid siphons. In univariate analysis, being male (p < 0.001) and having total cholesterol blood levels <240 mg/dL (p = 0.022) were associated with a higher AA diameter. Also in univariate analysis, the mean AA diameter was higher in individuals with an increased cIMT (p = 0.021), but such association disappeared in adjusted models. The AA diameter was not associated with high calcium content in the carotid siphons in either univariate or multivariate analyses. This population study shows no association between the AA diameter and cervicocephalic atherosclerosis in community-dwelling older adults, suggesting a non-atherosclerotic origin of AA aneurysms.

Increased Aortic Diameters on Multidetector Computed Tomographic Scan Are Independent Predictors of Incident Adverse Cardiovascular Events: The Framingham Heart Study

BACKGROUND

Adverse aortic remodeling, such as dilation, is associated with multiple cardiovascular disease (CVD) risk factors. We sought to determine whether measures of enlarged aortic diameters improve prediction of incident adverse CVD events above standard CVD risk factors in a community-dwelling cohort.

METHODS AND RESULTS

Participants from the Framingham Offspring and Third Generation Cohorts (n=3318; aged 48.9±10.3 years), who underwent noncontrast thoracic and abdominal multidetector computed tomography during 2002 to 2005, had complete risk factor profiles, and were free of clinical CVD, were included in this study. Diameters were measured at 4 anatomically defined locations: the ascending thoracic aorta, descending thoracic aorta, the infrarenal abdominal aorta, and lower abdominal aorta. Adverse events comprised CVD death, myocardial infarction, coronary insufficiency, index admission for heart failure, and stroke. Each aortic segment was dichotomized as enlarged (diameter ≥upper 90th percentile for age, sex, and body surface area) or not enlarged; the hazard of an adverse event for an enlarged segment was determined using multivariable-adjusted Cox proportional hazards models. Over a mean 8.8±2.0 years of follow-up, there were 177 incident adverse CVD events. In models adjusted for traditional CVD risk factors, enlarged infrarenal abdominal aorta (hazard ratio=1.57; 95% confidence interval=1.06 to 2.32) and lower abdominal aorta (hazard ratio=1.53; 95% confidence interval=1.00 to 2.34) were associated with an increased hazard of CVD events. Enlarged ascending thoracic aorta and descending thoracic aorta were not significantly associated with CVD events.

CONCLUSIONS

Among community-dwelling adults initially free of clinical CVD, enlarged infrarenal abdominal aorta and lower abdominal aorta, on noncontrast multidetector computed tomography scans, are independent predictors of incident adverse CVD events above traditional risk factors alone.

Infrarenal aortic diameter, aortoiliac bifurcation level and lumbar disc degenerative changes: a cross-sectional MR study

PURPOSE

To examine a possible correlation of infrarenal aortic diameter and aortoiliac bifurcation level with lumbar disc degenerative changes.

METHODS

This was a cross-sectional, single-center retrospective study on lumbar magnetic resonance images of patients with low back pain (n = 496). Lumbar disc degenerative changes were reported on the basis of the Pfirrmann grading system and accordingly, patients were grouped as with grade I-II findings (n = 192), with grade III findings (n = 64) and with grade IV-V findings (n = 240). The groups were matched for sex, body mass index and the history of diabetes mellitus, hypertension, hyperlipidemia and smoking. Infrarenal aortic diameter and aortoiliac bifurcation level were compared between the three groups.

RESULTS

Pairwise comparisons between the three groups of patients with Pfirrmann grades of I-II, III and IV-V revealed significant differences (p < 0.05) in terms of the median infrarenal aortic diameter (17 mm [interquartile range 4], 18 mm [4] and 19 mm [4], respectively) and the median aortoiliac bifurcation level (3 [2], 4 [2] and 5 [3], respectively; the higher the value, the more the caudal displacement). These associations were independent of conventional risk factors of atherosclerosis (including age) and from each other.

CONCLUSIONS

This study showed a significant, direct correlation of the infrarenal aortic diameter and the level of aortoiliac bifurcation with lumbar intervertebral degenerative changes according to the Pfirrmann grading system. The associations were independent of well-known risk factors of atherosclerosis and from each other.

Lower Aorto-Iliac Bifurcation Position and Incident Cardiovascular Disease: A Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

With increasing age, a downward shift of the aorto-iliac bifurcation relative to the lumbar spine occurs. A lower bifurcation position is an independent marker for adverse vascular aging and is associated with increased burden of cardiovascular disease (CVD) risk factors; however, the associations between lower bifurcation position and CVD events remain unknown.

METHODS

Abdominal computed tomography scans were used to measure the aorto-iliac bifurcation distance (AIBD, distance from the aorto-iliac bifurcation to the L5/S1 disc space). Cox proportional hazard analysis was used to determine the independent hazard of a lower bifurcation position (smaller AIBD) for incident coronary heart disease (CHD, defined as myocardial infarction, resuscitated cardiac arrest, or sudden cardiac death), CVD (CHD plus stroke or stroke death), and all-cause mortality (ACM).

RESULTS

In the 1,711 study participants (51% male), the mean AIBD was 26 ± 15 mm. After a median follow-up of 10 years, 63 (3.7%) developed CHD, 100 (5.8%) developed CVD, and 129 (7.5%) were deceased. Compared to the 4^th quartile of AIBD (highest bifurcation position), participants in the 1^st quartile (lowest bifurcation position) had increased risk for CHD (hazard ratio (HR) = 1.5, 95% confidence interval (CI): 0.8-3.0, P = 0.2), CVD (HR = 1.8, 95% CI: 0.9-2.7, P = 0.1), and ACM (HR = 2.2, 95% CI: 1.3-3.6, P = 0.01). After adjustments for CVD risk factors, the HR for ACM was no longer significant.

CONCLUSION

Despite being an independent marker for adverse vascular changes in the aorta, a lower aorto-iliac bifurcation position was not independently associated with future CVD events. The opposing effects of atherosclerosis and stiffness in the aorta may, in part, explain our null findings.

Predictors Associated With Increased Prevalence of Abdominal Aortic Aneurysm in Chinese Patients with Atherosclerotic Risk Factors

OBJECTIVE/BACKGROUND

Epidemiological screening studies have demonstrated that the prevalence of abdominal aortic aneurysm (AAA) of Asian origin appears to be low and so increases uncertainty about the cost effectiveness of screening for AAAs in Chinese people. Some studies have demonstrated a higher prevalence of AAA in patients with atherosclerotic risk factors. The purpose of the study was to determine the prevalence of AAA and to explore the high risk group of AAA in Chinese patients with atherosclerotic risk factors.

METHODS

From November 2014 to July 2015, a prospective observational study was conducted in Guangdong General Hospital. In total, 1582 consecutive patients with atherosclerotic risk factors and undergoing coronary angiography for suspected or known coronary artery disease were enrolled to be screened for AAA by abdominal aortic ultrasound. Because of inadequate ultrasound image quality, the analysis was based on the 1541 (97.4%) patients whose abdominal aortic ultrasound images were adequate.

RESULTS

The prevalence of AAA was 1.6% in the whole study population and 2.9% in male patients aged over 65 years. In multivariate analysis, age ≥ 65 years (p = .029), smoking (p = .037), hypertension (p = .026), and aortic root diameter > 30 mm (p = .003) were independent predictors of AAA. The prevalence of AAA was 0% (0/153) in patients without any independent predictor, 0.6% (3/502) in patients with one predictor, 1.0% (6/597) in patients with two predictors, 4.8% (12/249) in patients with three predictors, and up to 10% (4/40) in patients with four predictors (p<.001; p value for trend < .001).

CONCLUSION

Age ≥ 65 years, smoking, hypertension, and aortic root diameter > 30 mm emerged as independent predictors of AAA in Chinese patients. Stepwise increases in the prevalence of AAA were found to depend on the number of independent predictors. Ultrasound screening for AAA could be considered in these high risk patients, especially those with three or four predictors.

Greater Volume but not Higher Density of Abdominal Aortic Calcium Is Associated With Increased Cardiovascular Disease Risk: MESA (Multi-Ethnic Study of Atherosclerosis)

BACKGROUND

Abdominal aortic calcium (AAC) and coronary artery calcium (CAC) independently and similarly predict cardiovascular disease (CVD) events. The standard AAC and CAC score, the Agatston method, upweights for greater calcium density, thereby modeling higher calcium density as a CVD hazard.

METHODS AND RESULTS

Computed tomography scans were used to measure AAC and CAC volume and density in a multiethnic cohort of community-dwelling individuals, and Cox proportional hazard was used to determine their independent association with incident coronary heart disease (CHD, defined as myocardial infarction, resuscitated cardiac arrest, or CHD death), cardiovascular disease (CVD, defined as CHD plus stroke and stroke death), and all-cause mortality. In 997 participants with Agatston AAC and CAC scores >0, the mean age was 66±9 years, and 58% were men. During an average follow-up of 9 years, there were 77 CHD, 118 CVD, and 169 all-cause mortality events. In mutually adjusted models, additionally adjusted for CVD risk factors, an increase in ln(AAC volume) per standard deviation was significantly associated with increased all-cause mortality (hazard ratio=1.20; 95% confidence interval, 1.08-1.33; P<0.01) and an increased ln(CAC volume) per standard deviation was significantly associated with CHD (hazard ratio=1.17; 95% confidence interval, 1.04-1.59; P=0.02) and CVD (hazard ratio=1.20; 95% confidence interval, 1.05-1.36; P<0.01). In contrast, both AAC and CAC density were not significantly associated with CVD events.

CONCLUSIONS

The Agatston method of upweighting calcium scores for greater density may be inappropriate for CVD risk prediction in both the abdominal aorta and coronary arteries.

Peripheral Artery Disease and Aortic Disease

We reviewed published MESA (Multi-Ethnic Study of Atherosclerosis) study articles concerning peripheral arterial disease, subclavian stenosis (SS), abdominal aortic calcium (AAC), and thoracic artery calcium (TAC). Important findings include, compared to non-Hispanic whites, lower ankle-brachial index (ABI) and more SS in African Americans, and higher ABI and less SS in Hispanic and Chinese Americans. Abnormal ABI and brachial pressure differences were associated with other subclinical cardiovascular disease (CVD) measures. Both very high and low ABI independently predicted increased CVD events. Looking at aortic measures, TAC and AAC were significantly associated with other subclinical CVD measures. Comparisons of AAC with coronary artery calcium (CAC) showed that both were less common in ethnic minority groups. However, although CAC was much more common in men than in women in multivariable analysis, this was not true of AAC. Also, when AAC and CAC were adjusted for each other in multivariable analysis, there was a stronger association for AAC than for CAC with CVD and total mortality.

Endothelial and Metabolic Function Interactions in Overweight/Obese Children

AIM

Although the underlined mechanisms are still unknown, metabolic/coagulation alterations related to childhood obesity can induce vascular impairments. The aim of this study was to investigate the relationship between metabolic/coagulation parameters and endothelial function/vascular morphology in overweight/obese children.

METHODS

Thirty-five obese/overweight children (22 pre-pubertal, mean age: 9.52±3.35 years) were enrolled. Body mass index (BMI), homeostasis model assessment index (HOMAIR), metabolic and coagulation parameters, [adiponectin, fibrinogen, high molecular weight adiponectin (HMW), endothelin-1, and vonWillebrand factor antigen] ultrasound early markers of atherosclerosis [flow-mediated dilatation (FMD), common carotid intima-media thickness (C-IMT), and anteroposterior diameter of infra-renal abdominal aorta (APAO)] were assessed.

RESULTS

APAO was related to anthropometric (age: r=0.520, p=0.001; height: r=0.679, p＜0.001; weight: r=0.548, p=0.001; BMI: r=0.607, p＜0.001; SBP: r=0.377, p=0.026) and metabolic (HOMAIR: r=0.357, p=0.035; HMW: r=－0.355, p=0.036) parameters. Age, height, and systolic blood pressure were positively related to increased C-IMT (r=0.352, p=0.038; r=0.356, p=0.036; r=0.346, p=0.042, respectively). FMD was not related to any clinical and biochemical characteristics of the pediatric population. Age, HOMAIR, fasting glucose levels, and HMW were independent predictors for APAO increase. Each unit decrease in HMW concentrations (1 μg/ml) induced a 0.065 mm increase in APAO.

CONCLUSION

High molecular weight adiponectin is related to cardiovascular risk in overweight/obese children.

Hyperhomocysteinaemia is an independent risk factor of abdominal aortic aneurysm in a Chinese Han population

The associations between hyperhomocysteinaemia (HHcy), methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism, and abdominal aortic aneurysm (AAA) remain controversial, with only few studies focused on these associations within the Chinese population. We performed subgroup and interaction analyses in a Chinese Han population to investigate these associations. In all, 155 AAA patients and 310 control subjects were evaluated for serum total homocysteine levels and MTHFR C677T polymorphisms. Multiple logistic regression models were used to evaluate the aforementioned associations. Interaction and stratified analyses were conducted according to age, sex, smoking status, drinking status, and chronic disease histories. The multiple logistic analyses showed a significant association between HHcy and AAA but no significant association between MTHFR C677T polymorphism and AAA. The interaction analysis showed that age and peripheral arterial disease played an interactive role in the association between HHcy and AAA, while drinking status played an interactive role in the association between MTHFR C677T polymorphism and AAA. In conclusion, HHcy is an independent risk factor of AAA in a Chinese Han population, especially in the elderly and peripheral arterial disease subgroups. Longitudinal studies and clinical trials aimed to reduce homocysteine levels are warranted to assess the causal nature of these relationships

Association of Resting Heart Rate with Infrarenal Aortic Diameter: A Cross Sectional Study in Chinese Hypertensive Adults

OBJECTIVE

Elevated resting heart rate (RHR) has been shown to be a risk marker for cardiovascular disease. Results from studies on the effects of RHR in large arteries are limited to the functional changes of those arteries, while the association between RHR and aortic diameter remains largely understudied.

METHODS

This was a cross sectional study of hypertensive Chinese adults from rural areas. The maximum infrarenal aortic diameter (maxIAD) from renal arteries to the iliac bifurcation was obtained by ultrasound. MaxIADs in different RHR groups were compared in males and females separately because of the significant differences between sexes. Multiple regression analysis was used to determinate the correlation between RHR and maxIAD. Further interactions between three factors (BMI, smoking, and anti-hypertensive regimens) and RHR for maxIAD were examined using subgroup analysis.

RESULTS

19,200 subjects were enrolled in the study, with an average age of 64.8±7.4 years and 61.6% females. Only 22 cases (0.11%) were detected with AAA, with males (n = 17) presenting a higher AAA incidence than females (n = 5). In subjects ≥65 years, there were 18 (0.19%) AAA, and 15 (83.3%) had a history of smoking. In the total subjects, the mean maxIAD ranged from 15.7±2.1 mm to 15.2±2.2 mm as RHR changed from the lowest quartile to the highest (≥84 bpm) in males, with a similar tendency observed in females. The correlation coefficient of RHR on maxIAD was -0.17 in males and -0.12 in females. Further subgroup analysis revealed that smoking exaggerated the correlation between RHR and maxIAD, but only in females.

CONCLUSIONS

A low AAA incidence was observed in this hypertensive Chinese population. There was a negative association between RHR and maxIAD, potentially exaggerated by smoking, especially in females.

Effectiveness of screening for abdominal aortic aneurysm during echocardiography

Screening patients with abdominal aortic aneurysm (AAA) is associated with reduced AAA-related mortality, but population screening is poorly implemented. Opportunistic screening during imaging for other indications might be efficient. Single-center series reported AAA rates of 0.8% to 6.5% in patients undergoing transthoracic echocardiography (TTE), with disparities due to selection bias. In this first multicenter study, we aimed to assess the feasibility and criteria for screening AAA during TTE in real-life practice. During a week of May 2011, 79 centers participated in a nationwide survey. All patients aged ≥65 years requiring TTE for any indication were eligible, except for those with operated abdominal aorta. We defined AAA by an anteroposterior diameter of the infrarenal aorta≥30 mm. Of 1,382 consecutive patients, abdominal aorta imaging was feasible in 96.7%, with a median delay of 1.7 minutes (>3 minutes in 3.6% of cases). We found AAA in 50 patients (3.7%). Unknown AAA (2.7%) was more frequent in men than women (3.7% vs 1.3%, respectively, p=0.007) and increased by age at 2.2%, 2.5%, and 5.8% in age bands of 65 to 74, 75 to 84, and 85+ years, respectively. None of the female participants aged <75 years had AAA. Smoking status and family history of AAA were significantly more frequent among patients with AAA. The ascending aorta was larger in those with AAA (36.2±4.7 vs 34.0±5.2 mm, p=0.006), and bicuspid aortic valve and/or major aortic regurgitation were also more frequent (8% vs 2.6%, p=0.017). In conclusion, rapid AAA screening during TTE is feasible and should be limited to men ≥65 years and women≥75 years.

Impact of obstructive sleep apnea on abdominal aortic diameters

Although obesity has been reported to be a potential risk factor for abdominal aortic dilatation, the impact of obstructive sleep apnea (OSA) on the abdominal aortic diameter remains unknown. We retrospectively reviewed 427 patients aged >45 years who underwent polysomnography and abdominal computed tomography from November 2008 to February 2012. Aortic diameters were measured at 3 locations: upper, infrarenal, and lower abdominal aorta. OSA was defined as non-OSA (apnea-hypopnea index [AHI] <10, n = 58), mild to moderate (AHI 10 to 30, n = 167), and severe (AHI ≥30, n = 202). Adjusted diameter was not significantly different among OSA severity categories at the upper (21.0, 21.3, and 21.4 mm, respectively) and infrarenal aorta (19.5, 20.2, and 19.9 mm, respectively) but was significantly different at the lower abdominal aorta (17.3, 18.2, and 18.2 mm, respectively, p = 0.006) with larger diameters in patients with OSA. Multivariate linear regression analyses revealed that risk profiles for aortic dilatation varied according to the location and gender and that OSA (AHI ≥10) was an independent risk factor for infrarenal and lower abdominal aortic dilatation only in men (β = 0.10 and 0.18, p = 0.049 and 0.001, respectively). In conclusion, OSA may enhance dilatation of the distal abdominal aorta in men.

Cardiovascular risk in patients with small and medium abdominal aortic aneurysms, and no history of cardiovascular disease

Background

Cardiovascular disease (CVD) is the main cause of death in people with abdominal aortic aneurysm (AAA). There is little evidence that screening for AAA reduces all-cause or cardiovascular mortality. The aim of the study was to assess whether subjects with a small or medium AAA (3·0–5·4 cm), without previous history of clinical CVD, had raised levels of CVD biomarkers or increased total mortality.

Methods

This prospective study included subjects with a small or medium AAA and controls, all without a history of clinical CVD. CVD biomarkers (high-sensitivity C-reactive protein, hs-CRP; heart-type fatty acid-binding protein, H-FABP) were measured, and survival was recorded.

Results

Of a total of 815 people, 476 with an AAA and 339 controls, a cohort of 86 with small or medium AAA (3–5·4 cm) and 158 controls, all with no clinical history of CVD, were identified. The groups were matched for age and sex. The AAA group had higher median (i.q.r.) levels of hs-CRP (2·8 (1·2–6·0) versus 1·3 (0·5–3·5) mg/l; P &lt; 0·001) and H-FABP (4·6 (3·5–6·0) versus 4·0 (3·3–5·1) µg/l; P = 0·011) than controls. Smoking was more common in the AAA group; however, hs-CRP and H-FABP levels were not related to smoking. Mean survival was lower in the AAA group: 6·3 (95 per cent confidence interval (c·i.) 5·6 to 6·9) years versus 8·0 (7·6 to 8·1) years in controls (P &lt; 0·001). Adjusted mortality was higher in the AAA group (hazard ratio 3·41, 95 per cent c·i. 2·11 to 9·19; P &lt; 0·001).

Conclusion

People with small or medium AAA and no clinical symptoms of CVD have higher levels of hs-CRP and H-FABP, and higher mortality compared with controls. They should continue to receive secondary prevention against CVD.

Interaction between widening of diameter of abdominal aorta and cardiovascular risk factors and atherosclerosis burden

The aim of this study was to investigate influence of traditional cardiovascular risk factors (CVRF) and subclinical atherosclerosis (ATS) burden on early stages of abdominal aortic diameter (AAD) widening among adults. 2,052 consecutive patients (P) (39 % women), mean age 52 ± 13 years, were prospectively screened for CVRF, ATS, and AAD. B-mode ultrasound was used to evaluate the largest AAD and to detect carotid and femoral atherosclerotic plaques. Mean AAD was 15.2 ± 2.8 mm. Atherosclerotic plaques were detected in 71 % of patients. Significant univariate correlation between AAD, traditional CVRF, and ABS was found. However, multiple regression analysis showed that only seven of them were significantly and weakly correlated with AAD (R² = 0.27, p < 0.001). On the other hand, a multivariate logistic analysis was used to evaluate CVRF impact on enlarged AAD ≥25 mm (EAAD) as compared to those with AAD <25 mm. These factors did not account for more than 30 % of interaction (R² = 0.30, p = 0.001). Furthermore, despite a large proportion of patients with high number of CVRF, and subclinical ATS, rate of patients with AAD ≥25 mm was low (1 %) and scattered regardless their CHD risk score or ATS burden. In conclusion, these results suggest that although some traditional CVRF and presence of ATS are associated with early stages of EAAD, other determinants still need to be identified for a better understanding of abdominal aortic aneurysm pathogenesis.

Associations of cardiovascular disease risk factors and calcified atherosclerosis with aortoiliac bifurcation position: the MultiEthnic Study of Atherosclerosis

We investigated associations of cardiovascular disease (CVD) risk factors and calcified atherosclerosis with aortoiliac bifurcation position. The bifurcation position was determined by measuring the distance from the aortoiliac bifurcation to the L5-S1 disk space (or aortoiliac bifurcation distance [AIBD]), using computed tomography scans. The 1711 study participants (51% male) had a mean age of 62 ± 10 years and a mean AIBD of 26 ± 15 mm. In multivariable linear regression, older age, male gender, smoking, hypertension, larger aortic diameter, and smaller lumbar height were each independently associated with a smaller AIBD (more caudal bifurcation position). In contrast, diabetes, elevated triglycerides, and increased pulse pressure were independently associated with a larger AIBD (more cephalad bifurcation position). These findings suggest that age-related bifurcation descent is associated with CVD markers for aortic disease. Future studies should assess whether the bifurcation position is an independent prognosticator for CVD.

Association of polymorphisms on chromosome 9p21.3 region with increased susceptibility of abdominal aortic aneurysm in a Chinese Han population

OBJECTIVE

Several studies have reported that polymorphisms on chromosome 9p21.3, near the CDKN2A/2B gene, are strongly associated with increased susceptibility to abdominal aortic aneurysm (AAA). However, no convincing data has been reported on a relationship between AAA and these variants in the Chinese Han population. The aim of this study was to evaluate the role of rs10757278 and rs1333049 in determining genetic susceptibility to AAA.

METHODS

A total of 155 AAA patients and 310 controls, comparable in age and gender, were enrolled in this study. DNA samples were genotyped for rs10757278 and rs1333049 using the MassArray system. The association between these two single nucleotide polymorphisms and AAAs was tested using multivariate logistic regression. Stratified analysis was also performed by clinical and laboratory features.

RESULTS

Single nucleotide polymorphisms rs10757278 and rs1333049 were significantly associated with increased risk of AAA. The frequencies of rs10757278-G and rs1333049-C in AAA patients were significantly higher than in control subjects (odds ratio [OR], 1.53; 95% confidence interval [CI], 1.11-2.11; P = .01, and OR, 1.48; 95% CI, 1.07-2.05; P = .02). Multiple logistic regression analysis indicated that, after adjusting for smoking habits, drinking habits, and histories of other chronic diseases, homozygosity of the risk allele for rs10758278-G and rs1333049-C also increased the likelihood of AAA (OR, 2.31; 95% CI, 1.22-4.36, and OR, 2.14; 95% CI, 1.13-4.05). The frequency of the GC haplotype was significantly higher in AAA patients than in control subjects (OR, 1.44; P = .038). Stratification analysis of clinical and laboratory features revealed no association between polymorphisms and aortic diameters in AAA patients. There was a significantly high frequency of the rs10757278 GG genotype in AAA patients with high serum total homocysteine compared with those control subjects with high serum total homocysteine (OR, 2.71; 95% CI, 1.12-6.58; P = .03) indicating that the genotype GG of rs10757278 might interact with the homocysteine biological pathway to stimulate the presence of AAA.

CONCLUSIONS

Present data demonstrate that rs10757278 and rs1333049 on chromosome 9p21.3 are significantly associated with increased risk of AAA in the Chinese population and emphasize the need to further study the role of these markers in AAA.

Reference diameters of the abdominal aorta and iliac arteries in the Korean population

PURPOSE

It is important to know the normal diameter of artery throughout the body so that clinicians are able to determine when an artery becomes aneurysmal. However, there are no previous studies on the normal diameter of arteries in the general Korean population. The purpose of this article is to determine the normal reference diameters of the abdominal aorta and iliac arteries in the Korean population.

MATERIALS AND METHODS

We recruited the study population from three cities in Korea for the abdominal aortic aneurysm (AAA) screening. We measured the diameter of the aorta and iliac arteries. We analyzed the reference diameter of the population without AAA. The results were analyzed by Student's t-test and ANOVA on SPSS version 19. A p value <0.05 was considered to be statistically significant.

RESULTS

One thousand two hundred and twenty-nine people were enrolled. 478 men and 751 women, with a mean age of 63.9 ± 10.1 years (range 50 to 91) were examined. Eleven out of 1229 (0.89%) were diagnosed with AAA. In the population of 1218 people without AAA, the mean diameters (cm) of male/female were 2.20/2.11 (p<0.001) at suprarenal, 2.04/1.90 (p<0.001) at renal, 1.90/1.79 (p<0.001) at infrarenal, 1.22/1.17 (p<0.001) at right iliac and 1.47/1.15 (p=0.097) at the left iliac, respectively. There was a significantly larger diameter in the male population. The diameter of each level increased with age.

CONCLUSION

The normal reference diameter of the infrarenal abdominal aorta in the Korean population is 1.9 cm in males and 1.79 cm in females. The diameter of the abdominal aorta increases with age.

The downward shift of the aortic bifurcation, a possible marker for vascular aging

PURPOSE

Radiographers in both clinical and research settings utilize lumbar vertebral landmarks (i.e. L5/S1) on scout films to guide imaging of the abdominal aorta. The aortic bifurcation is variably located along the anterior lower spine from L3 toL5. We sought to determine the mean distance from the aortic bifurcation to the L5-S1 disc space. We also investigated associations between cardiovascular disease (CVD) risk factors and calcified atherosclerosis to this distance.

METHODS

This study was a retrospective analysis of 748 participants who underwent abdominal computed tomography (CT) scans for assessment of subclinical cardiovascular disease. The CT scans were used to calculate calcium scores in six arterial beds, as well as the distance from the aortic bifurcation to the L5-S1 disc space.

RESULTS

Among 748 participants, the mean age was 58 ± 11 years, and 57% were male. The mean (SD) distance from the aortic bifurcation to the L5-S1 disc space was 52mm (16). There were no significant differences between males (53mm) and females (52mm). Older age was strongly associated with smaller distances, such that individuals < 50 years had bifurcations that were approximately 19mm further from the L5-S1 disc compared to those ≥ 70 years (P< 0.01). In multivariable analysis, older age, along with lower BMI and smoking were each independently associated with a smaller distance, (P <0.01). Arterial calcification was not significantly associated with this distance.

CONCLUSIONS

The distance from the aortic bifurcation to the L5-S1 disc is smaller in persons with advanced age, lower BMI, and a history of smoking. These associations may reflect a downward shift, which warrants consideration in studies planning to image the abdominal aorta. This downward shift may be a useful marker for vascular aging. Also, further investigations are needed to understand the mechanisms and implications of this descent.