Thoracic and abdominal aortic dimension in 70-year-old men and women – A population-based whole-body magnetic resonance imaging (MRI) study

How to improve epidemiological trustworthiness concerning abdominal aortic aneurysms

BackgroundResearch on degenerative abdominal aortic aneurysms (AAA) is hampered by complex pathophysiology, sub-optimal pre-clinical models, and lack of effective medical therapies. In addition, trustworthiness of existing epidemiological data is impaired by elements of ambiguity, inaccuracy, and inconsistency. Our aim is to foster debate concerning the trustworthiness of AAA epidemiological data and to discuss potential solutions.MethodsWe searched the literature from the last five decades for relevant epidemiological data concerning AAA development, rupture, and repair. We then discussed the main issues burdening existing AAA epidemiological figures and proposed suggestions potentially beneficial to AAA diagnosis, prognostication, and management.ResultsRecent data suggest a heterogeneous scenario concerning AAA epidemiology with rates markedly varying by country and study cohorts. Overall, AAA prevalence seems to be decreasing worldwide while mortality is apparently increasing regardless of recent improvements in aortic-repair techniques. Prevalence and mortality are decreasing in high-income countries, whereas low-income countries show an increase in both. However, several pieces of information are missing or outdated, thus systematic renewal is necessary. Current AAA definition and surgical criteria do not consider inter-individual variability of baseline aortic size, further decreasing their reliability.ConclusionsSwitching from flat aortic-size thresholds to relative aortic indices would improve epidemiological trustworthiness regarding AAAs. Aortometry standardization focusing on simplicity, univocity, and accuracy is crucial. A patient-tailored approach integrating clinical data, multi-adjusted indices, and imaging parameters is desirable. Several novel imaging modalities boast promising profiles for investigating the aortic wall. New contrast agents, computational analyses, and artificial intelligence-powered software could provide further improvements.

The effect of aneurysm diameter on perioperative outcomes following complex endovascular repair

OBJECTIVES

Endovascular aneurysm repair (EVAR) for large infrarenal abdominal aortic aneurysms (AAAs) has been associated with worse outcomes compared with EVAR for smaller AAAs. Whether these findings apply to complex AAAs (cAAA) remains uncertain.

METHODS

We identified all intact complex EVAR (cEVAR) from 2012 to 2024 in the Vascular Quality Initiative. cEVAR was defined as having a proximal extent between zones 6 and 9 and at least one side branch/fenestration/chimney/parallel grafting. Aneurysm size was defined as follows: large: >65 mm (males), >60 mm (females); medium: 55 to 65 mm (males), 50 to 60 mm (females); and small: <55 mm (males), <50 mm (females). We assessed perioperative death, any complication, and in-hospital reintervention using logistic regression and midterm mortality using adjusted Kaplan-Meier methods and Cox regression analyses. Medium-sized aneurysms were compared with large and small aneurysms.

RESULTS

Of the 3426 patients, 22.6% had large, 60.4% medium, and 17.0% had small aneurysms. As compared with medium and small aneurysms, large aneurysms demonstrated higher rates of perioperative death (4.8% vs 2.6% vs 0.5%), any complication (33.3% vs 23.6% vs 19.4%), and in-hospital reintervention (6.2% vs 4.0% vs 2.6%) (all P < .05). The median follow-up was 445 days. One-year mortality rates were higher in large aneurysms (12.3% vs 7.8% vs 3.8%; P < .001). After adjustment, when compared with medium-sized aneurysms, large aneurysms were associated with a significantly higher risk of perioperative death (adjusted odds ratio [aOR], 1.73; 95% confidence interval [CI], 1.09-2.72), any complication (aOR, 1.44; 95% CI, 1.18-1.76), and midterm mortality (adjusted hazard ratio, 1.50; 95% CI, 1.19-1.88), but not in-hospital reintervention (aOR, 1.46; 95% CI, 0.99-2.13). Although small aneurysms, as compared with medium-sized aneurysms, did not demonstrate a difference in any complication (aOR, 0.87; 95% CI, 0.68-1.10), in-hospital reintervention (aOR, 0.77; 95% CI, 0.42-1.33), and midterm mortality (adjusted hazard ratio, 0.78; 95% CI, 0.57-1.08], they did demonstrate a lower risk of perioperative death (aOR, 0.26; 95% CI, 0.06-0.71).

CONCLUSIONS

In cEVAR for cAAA, large aneurysms, compared with medium-sized aneurysms, were associated with higher rates of perioperative death, any complication, and midterm mortality, with in-hospital reinterventions trending toward a statistically significant higher risk. Although these results align with expectations, they emphasize the importance of effectively managing patients with large cAAAs and highlight the need for future research to determine whether patients might benefit more from medical therapy or open repair.

Hyperglycemia inhibits AAA expansion: examining the role of lysyl oxidase

Abdominal aortic aneurysm (AAA) is a common, progressive, and potentially fatal dilation of the most distal aortic segment. Multiple studies with longitudinal follow-up of AAA have identified markedly slower progression among patients affected with diabetes. Understanding the molecular pathway responsible for the growth inhibition could have implications for therapy in nondiabetic patients with AAA. Toward this end, we investigated the effects of hyperglycemia in a murine model of AAA and a carefully monitored cohort of patients with AAA from the Noninvasive Treatment of AAA-Clinical Trial (NTA3CT). In mice with hyperglycemia, AAA growth was inhibited to a similar degree (∼30%) as seen in patients with diabetes. AAA growth correlated inversely to levels of hyperglycemia in mice and patients with AAA. Inhibiting lysyl oxidase (LOX) activity increases aneurysm growth and matrix degradation in this model. Hyperglycemia increased LOX concentration in aortic smooth muscle cells (SMCs) but not in murine AAA tissue. Inhibiting LOX activity completely blocked the growth-inhibitory effect of hyperglycemia. Lysyl oxidase-like 2 (LOXL2), the primary arterial isoform of LOX, is expressed in the same area as type IV collagen along the outer media in murine AAA tissue. There is a significant inverse correlation between LOXL2 and AAA growth rates in patients. Taken together, these studies suggest a role for LOXL2-mediated type IV collagen crosslinking in slowing AAA growth in the setting of hyperglycemia.NEW & NOTEWORTHY AAA grows slower in patients affected by diabetes. This growth inhibition is lost when the enzyme lysyl oxidase (LOX) is blocked in diabetic mice. The predominant arterial isoform of LOX, LOX-like 2 (LOXL2), overlaps with type IV collagen in the outer media of murine aneurysm tissue. Circulating LOXL2 correlates inversely with AAA growth in patients. Type IV collagen cross-linking by LOXL2 may play a role in the AAA growth inhibition associated with diabetes.

Female-Specific Considerations in Aortic Health and Disease

The aorta plays a central role in the modulation of blood flow to supply end organs and to optimize the workload of the left ventricle. The constant interaction of the arterial wall with protective and deleterious circulating factors, and the cumulative exposure to ventriculoarterial pulsatile load, with its associated intimal-medial changes, are important players in the complex process of vascular aging. Vascular aging is also modulated by biomolecular processes such as oxidative stress, genomic instability, and cellular senescence. Concomitantly with well-established cardiometabolic and sex-specific risk factors and environmental stressors, arterial stiffness is associated with cardiovascular disease, which remains the leading cause of morbidity and mortality in women worldwide. Sexual dimorphisms in aortic health and disease are increasingly recognized and explain-at least in part-some of the observable sex differences in cardiovascular disease, which will be explored in this review. Specifically, we will discuss how biological sex affects arterial health and vascular aging and the implications this has for development of certain cardiovascular diseases uniquely or predominantly affecting women. We will then expand on sex differences in thoracic and abdominal aortic aneurysms, with special considerations for aortopathies in pregnancy.

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.

Gender Differences in Aortic Anatomic Severity Grade and Long-Term Survival Following Elective Abdominal Aortic Aneurysm Repair at a Single Tertiary Center

BACKGROUND

Anatomic severity grade (ASG) score is utilized to assess preoperative abdominal aortic aneurysms (AAA) and provide a quantitative data on its anatomic complexity. The aim of this study is to determine the anatomical differences and long-term survival between male and female patients undergoing elective AAA repair.

METHODS

All patients undergoing intact AAA repair from 2007 to 2014 were included. ASG scores were calculated based on preoperative anatomical characteristics including aortic neck, aneurysm, and iliac artery. Standard univariate analysis was used to evaluate patient and anatomical characteristics. Kaplan-Meier survival curves were used to evaluate long-term survival at 1 and 5 years.

RESULTS

A total of 379 patients were identified, of which, majority of them were males (80%). Females were on average 3 years older (mean [SD]: 74.32 [8.63] vs. 71.92 [8.64] years) and were more likely to undergo open repair (29.7% vs. 17.5%) (both P < 0.05). Both groups had similar comorbidities. The mean long-term follow-up (S.D.) was 6.21 (3.81) years. No significant difference was seen between males versus females in long-term survival at both 1 year (86.3% vs. 92.8, P = 0.06) and 5 year (68.5% vs. 72.7%, P = 0.38). In regard to the anatomical characteristics, females had shorter aortic neck length (mean in mm [S.D.]: 17.67 [1.41] vs. 27.20 [15.76]), increased tortuosity index [mean (S.D.): 1.11 (0.07) vs. 1.09 (0.07)]) and higher calcification [mean % (S.D.): 17.12 (21.17) vs. 10.59 (16.82)] (All P < 0.05). In contrast, males had larger aortic neck (mean in mm (S.D.): 23.81 (4.17) vs. 22.41 (4.16)] and iliac artery [mean in mm (S.D.): 7.70 (1.91) vs. 6.28 (1.67)] diameter (both P < 0.05). The mean total ASG score was significantly higher among females versus males [mean (S.D.): 17.23 (4.01) vs. 15.67 (3.96), P = 0.003]. After stratifying by ASG score ≥15, females had significantly lower survival at 1 year compared to males (82.6% vs. 92.1%, P = 0.04). However, this difference disappeared at 5 years.

CONCLUSIONS

The data demonstrate that females present at an older age with more complex AAA anatomy than males. Based on anatomical complexities, females were more likely to undergo open repair, with a corresponding increase in 1-year mortality, but not at 5 year. The data suggest that care processes for optimization of aortic surgery in females are needed to improve 1-year survival.

Reference Values of Cerebral Artery Diameters of the Anterior Circulation by Digital Subtraction Angiography: A Retrospective Study

A threshold-based classification of cerebral vasospasm needs reference values for intracranial vessel diameters on digital subtraction angiography (DSA). We aimed to generate adjusted reference values for this purpose by retrospectively analyzing angiograms and potential influencing factors on vessel diameters. Angiograms of the anterior circulation were evaluated in 278 patients aged 18−81 years. The vessel diameters of 453 angiograms (175 bilateral) were gathered from nine defined measuring sites. The effect sizes of physical characteristics (i.e., body weight and height, body mass index, gender, age, and cranial side) and anatomical variations were calculated with MANOVA. Segments bearing aneurysms were excluded for the calculation of reference values. Adjusted vessel diameters were calculated via linear regression analysis of the vessel diameter data. Vessel diameters increased with age and body height. Male and right-sided vessels were larger in diameter. Of the anatomical variations, only the hypoplastic/aplastic A1 segment had a significant influence (p < 0.05) on values of the anterior cerebral artery and the internal carotid artery with a small effect size (|ω2| > 0.01) being excluded from the reference values. We provide gender-, age-, and side-adjusted reference values and nomograms of arterial vessel diameters in the anterior circulation.

Normal diameters of abdominal aorta and common iliac artery in middle-aged and elderly Chinese Han people based on CTA

To investigate the normal diameter of the abdominal aorta and common iliac arteries of the middle-aged and elderly people in China and the relationship of the diameters with age, sex, height, weight, body mass index (BMI), and body surface area (BSA). This retrospective study enrolled 625 patients including 380 males and 245 females aged 60.00 years (interquartile range 13.00 years). All clinical data and the diameters of the abdominal aorta and common iliac arteries were analyzed. The diameter of the abdominal aorta was 21.49 ± 2.49 mm at the proximal, 16.94 (interquartile range 2.39) mm at the middle, and 15.65 (interquartile range 2.90) mm at the distal segment. The diameter of the common iliac artery was 10.76 (interquartile range 1.99) mm at the right proximal, 10.41 (interquartile range 2.05) mm at the left proximal, 10.74 (interquartile range 2.25) mm at the right distal, and 10.67 (interquartile range 2.22) mm at the left distal segment. The height, weight, BSA, BMI, diameters of the proximal, middle and distal abdominal aorta as well as the proximal and distal left and right common iliac arteries were significantly higher in males than those in females (P < .001). Height, weight, BSA, and BMI were significantly (P < .001) positively correlated with the diameter of the abdominal aorta and common iliac artery at the proximal, middle, and distal segments. The middle and distal diameters of the abdominal aorta were significantly higher in males than those in females (P < .05). The diameter of the abdominal aorta at the proximal, middle, and distal segment as well as the diameter of the left and right common iliac artery at the distal segment were significantly (P < .05) increased with age. The normal values of the diameter of the abdominal aorta and common iliac arteries are suggested for the middle-aged and elderly Chinese people for clinical reference. The diameters are gender related and significantly positively correlated with BSA, height, weight, and BMI, which is beneficial for the diagnosis and treatment planning of relevant vascular diseases.

Editor's Choice - Systematic Review and Meta-Analysis of Normal Infrarenal Aortic Diameter in the General Worldwide Population and Changes in Recent Decades

OBJECTIVE

To analyse the characteristics of normal infrarenal aortic diameter (AD) in the general worldwide population, to examine changes over time, and to investigate geographical differences.

DATA SOURCES

PubMed, Cochrane Library, and Web of Science.

REVIEW METHODS

This was a systematic review and meta-analysis of studies published up to October 2020 describing infrarenal AD measured by ultrasound in the general adult population. The study was conducted in accordance with the PRISMA statement and placed no restrictions on geographical location or year of publication. Studies of individuals pre-selected for certain diseases or risk factors and opportunistic screening were excluded. A random effects model was used to estimate pooled mean AD, and meta-regression analysis was used to study the effects of determinants of AD.

RESULTS

Thirty-two studies were included, reporting data for 941 144 individuals (98% were men). The pooled mean AD was 19.4 mm (95% confidence interval [CI] 18.8 - 20.1), being 20.1 mm (95% CI 19.4 - 20.8) in men and 17.8 mm (95% CI 16.5 - 19.1) in women (p < .001). Outer edge to outer edge (OTO) caliper placement method (p = .015) and body surface area (BSA; p = .010) were significantly associated with larger AD. In men, the largest mean AD was observed in Oceania (p < .001) and the smallest in Asia (p < .020). As none of the studies collected data between 2002 and 2007, the studies were divided into two periods: 2001 and before, and 2008 and after. All recent studies were European, with the diameters being significantly smaller (p = .003) in the latter period (18.3 mm [95% CI 17.5 - 19.1] vs. 20.7 mm [95% CI 19.1 - 22.3]). In the meta-regression models, the reduction in AD over time remained significant after adjustment for potential effect modifiers such as sex, age, geographical area, body size, cardiovascular risk factors, and ultrasound method.

CONCLUSION

Mean infrarenal AD in older European adults has decreased significantly in recent decades. Male sex, BSA, and OTO ultrasound measurement method are associated with larger AD, and geographical differences were observed in men.

The Impact of Suprarenal Diameter on Outcomes Following Endovascular Aneurysm Repair: A Retrospective Cohort Study

OBJECTIVES

To determine the association between suprarenal aortic diameters and complications that may be attributed to a dilating phenotype following endovascular abdominal aortic aneurysm repair.

DESIGN

This study is a retrospective review.

METHODS

We measured the abdominal aortas of 147 consecutive patients with a mean age of 78.5 (range 60-93) years, who had a mean Endovascular aneurysm repair (EVAR) follow-up of 3 years (6 months to 8 years) at a public Hospital. Aortic calibres measured 5 mm above the highest renal artery were recorded, patients were categorised according to suprarenal diameter; Group A: greater than 25 mm, Group B: less than or equal to 25 mm. Stent migration, aneurysmal sac growth, presence of an endoleak and its type, occlusion events, rupture, interventions and mortality, as well as clinical history and demographic data were compared between groups.

RESULTS

There was a significantly higher occurrence of stent migration (11% v 0%; P = .01) in patients with larger suprarenal aortas (Group A). The occurrence of any endoleak did not differ between the groups, however, significantly more complications resulting in secondary intervention, excluding occlusions, were noted in Group A (34% vs 17%, P = .04).

CONCLUSIONS

The results from this study suggest that patients with above-average suprarenal diameters (categorised as dilators) may have a higher occurrence of specific complications following EVAR. A more detailed study to establish the association of suprarenal calibre with types of complications following EVAR is warranted.

AAA Revisited: A Comprehensive Review of Risk Factors, Management, and Hallmarks of Pathogenesis

Despite declining incidence and mortality rates in many countries, the abdominal aortic aneurysm (AAA) continues to represent a life-threatening cardiovascular condition with an overall prevalence of about 2-3% in the industrialized world. While the risk of AAA development is considerably higher for men of advanced age with a history of smoking, screening programs serve to detect the often asymptomatic condition and prevent aortic rupture with an associated death rate of up to 80%. This review summarizes the current knowledge on identified risk factors, the multifactorial process of pathogenesis, as well as the latest advances in medical treatment and surgical repair to provide a perspective for AAA management.

Abdominal Aortic and Visceral Artery Aneurysms

Abdominal aortic aneurysms account for nearly 9000 deaths annually, with ruptured abdominal aortic aneurysms being the thirteenth leading cause of death in the United States. Abdominal aortic aneurysms can be detected by screening, but a majority are detected incidentally. Visceral artery aneurysms are often discovered incidentally, and treatment is guided by symptoms, etiology, and size. A timely diagnosis and referral to a vascular specialist are essential for timely open or endovascular repair and to ensure successful patient outcomes.

Sex-specific criteria for repair should be utilized in patients undergoing aortic aneurysm repair

OBJECTIVE

Female patients are more likely to undergo repair of intact and ruptured abdominal aortic aneurysm (AAA) at smaller aortic diameter compared with male patients. By adjusting for inherent anatomic differences between sexes, aortic size index (ASI) and aortic height index (AHI) may provide an additional method for guiding treatment. We therefore analyzed sex-specific criteria for AAA repair using aortic diameter, ASI, and AHI.

METHODS

We identified all patients who underwent AAA repair between 2003 and 2019 in the Vascular Quality Initiative database. The Dubois and Dubois formula was used to calculate body surface area; aortic diameter was divided by body surface area to calculate ASI. Aortic diameter was divided by height to calculate AHI. Cumulative distribution curves were used to plot the proportion of patients who underwent repair of ruptured aneurysm according to aortic diameter, ASI, and AHI. Multivariable logistic regression modeling was used to identify the association of female sex with perioperative mortality and any major postoperative complication.

RESULTS

We identified 55,647 patients, of whom 12,664 were female (20%). For both intact and rupture repair, female patients were older, less likely to undergo endovascular aneurysm repair, and more likely to have comorbid conditions. Female patients underwent repair at smaller median aortic diameter compared with male patients for intact (5.4 vs 5.5 cm; P < .001) and rupture repair (6.7 vs 7.7 cm; P < .001). However, ASI was higher in female patients for both intact (3.1 vs 2.7 cm/m²; P < .001) and rupture repair (3.8 vs 3.7 cm/m²; P < .001), whereas AHI was higher in female patients for intact repair (3.3 vs 3.1 cm/m; P < .001) but lower for rupture repair (4.1 vs 4.3 cm/m; P < .001). When analyzing the cumulative distribution of rupture repair in male patients, 12% of rupture repairs were performed at an aortic diameter below 5.5 cm. To achieve the same proportion of rupture repair in female patients, the repair diameter was only 4.9 cm. However, when ASI and AHI were used, female and male patients both reached 12% of rupture repair at an ASI of 2.7 cm/m² and an AHI of 3.0 cm/m.

CONCLUSION

Our study provides data to strongly support the sex-specific 5.0-cm aortic diameter threshold suggested for repair in female patients by the Society for Vascular Surgery. The high percentage of patients undergoing rupture repair below 5.5 cm in male patients and 5.0 cm in female patients highlights the need to better identify patients at risk of rupture at smaller aortic diameters.

Prevalence of Thoracic Aortic Aneurysms in Patients with Degenerative Abdominal Aortic Aneurysms: Results from the Prospective ACTA Study

OBJECTIVE

There are no recommendations for screening for thoracic aortic aneurysms (TAAs), even in patients with infrarenal abdominal aortic aneurysms (AAAs). The aims of this study were to determine the prevalence of TAAs in patients with AAAs and to analyse the risk factors for this association.

METHODS

This was a multicentre prospective study. The Aortic Concomitant Thoracic and Abdominal Aneurysm (ACTA) study included 331 patients with infrarenal AAAs > 40 mm between September 2012 and May 2016. These patients were prospectively enrolled in three French academic hospitals.

RESULTS

Patients were classified as having a normal, aneurysmal, or ectatic (non-normal, non-aneurysmal) thoracic aorta according to their maximum aortic diameter indexed by sex, age, and body surface area. Thoracic aortic ectasia (TAE) was defined as above or equal to the 90th percentile of normal aortic diameters according to gender and body surface area. Descending TAA was defined as ≥ 150% of the mean normal value, and ascending TAA as > 47 mm in men and 42 mm in women; 7.6% (n = 25) had either an ascending (seven cases; 2.2%) or descending aortic TAA (18 cases; 5.4%), and 54.6% (n = 181) had a TAE. Among the 25 patients with TAAs, five required surgery; two patients had TAAs related to penetrating aortic ulcers < 60 mm in diameter, and three had a TAA > 60 mm. In the multinomial regression analysis, atrial fibrillation (AF) (odds ratio [OR] 11.36, 95% confidence interval [CI] 2.18 - 59.13; p = .004) and mild aortic valvulopathy (OR 2.89, 1.04-8.05; p = .042) were independent factors associated with TAAs. Age (OR 1.06, CI 1.02 - 1.09; p = .003) and AF (OR 4.36, 1.21 - 15.61; p = .024) were independently associated with ectasia.

CONCLUSION

This study confirmed that TAAs coexisting with AAAs are not rare, and one fifth of these TAAs are treated surgically. Systematic screening by imaging the whole aorta in patients with AAAs is clinically relevant and should lead to an effective prevention policy.

Cost-Effectiveness of Endovascular Versus Open Repair of Abdominal Aortic Aneurysm: A Systematic Review

PURPOSE

Abdominal aortic aneurysm (AAA) is a life-threatening condition which, in the absence of increasing diameter or rupture, often remains asymptomatic, and a diameter greater than 5.5 cm requires elective surgical repair. This study aimed to evaluate the cost-effectiveness of endovascular repair (EVAR) versus open surgical repair (OSR) in patients with AAA through a systematic review of published health economics studies.

METHODS

Using a systematic review method, an electronic search was conducted for cost-effectiveness studies published on AAA (both in English and Persian) on PubMed, Embase, ISI/Web of Science (WoS), SCOPUS, Global Health databases, and the national databases of Iran from 1990 to 2020 including the keywords "cost-effectiveness", "endovascular", "open surgical", and "abdominal aortic aneurysms". The quality of the studies was assessed using the Quality of Health Economic Studies (QHES) checklist.

RESULTS

In total, 958 studies were found, of which 16 were eligible for further study. All studies were conducted in developed countries, and quality-adjusted life years (QALY) and life years (LY) were used to measure the outcomes. According to the QHES checklist, most studies were of good quality. In European countries and Canada, EVAR has not been cost-effective, while most studies in the United States regard this technique as a cost-effective intervention. For example, incremental cost-effectiveness ratio (ICER) values ranged from $14,252.12 to $34,446.37 per QALY in the USA, while ICER was €116,600.40 per QALY in Portugal.

CONCLUSION

According to the results, the EVAR technique has been more cost-effective than OSR for high-risk patients, but the need for continuous follow-up, increased costs, and re-intervention over the long term and for low-risk patients has reduced the cost-effectiveness of this method. As the health systems vary among different countries (i.e. quality of care, cost of devices, etc.), and due to the heterogeneity of studies in terms of the follow-up period, time horizon, and threshold, all of which are inherent features of economic evaluation, generalizing the results should be done with much caution, and policymaking must be based on national evidence.

Normal Diameter and Growth Rate of Infrarenal Aorta and Common Iliac Artery in Chinese Population Measured by Contrast-Enhanced Computed Tomography

BACKGROUND

In previous studies, the growth rate and diameter of infrarenal aorta was paucity of Chinese data. This study aim to evaluate the normal inside diameter and growth rate of the infrarenal aorta and common iliac artery in Chinese adult population and to explore the relationship between related factors and the arterial diameter.

METHODS

A retrospective study was performed among 1,340 hospitalized adult patients undergoing contrast-enhanced abdominopelvic computed tomography from April 2017 to March 2018 in our hospital. The inside diameter of infrarenal aorta and common iliac artery was measured. Linear regression was used to analyze the relationship between various factors and arterial diameter. Kruskal-Wallis H test was used to analyze the relationship between the arterial diameter and age. Mann-Whitney U test was used to analyze the relationship between arterial diameter and sex.

RESULTS

The inside diameter of the infrarenal aorta was 16.49 ± 2.12 mm in male patients and 14.50 ± 1.73 mm in female patients. In male patients, the right common iliac artery was 9.77 ± 1.75 mm, and the left was 9.65 ± 1.76 mm. In female patients, the right common iliac artery was 8.59 ± 1.31 mm and the left was 8.45 ± 1.28 mm. Comparing the oldest group with the youngest, the infrarenal aortic diameter increased 27.32% in male patients and 30.11% in female patients. Right common iliac artery increased 25.13% in male patients and 30.30% in female patients. Left common iliac artery increased 25.19% in male patients and 34.26% in female patients. The growth rate increased at the beginning, reached its peak at the age of 50-60 years, and then decreased. Multiple linear regression analysis results showed that sex, age, body surface area (BSA), hypertension, and cancer were significantly correlated with the diameter of infrarenal aorta. Sex, age, BSA, and hypertension were correlated with the diameter of right common iliac artery. Sex, age, BSA, and cancer were correlated with the diameter of left common iliac artery.

CONCLUSIONS

The diameter of the infrarenal abdominal aorta and common iliac artery of Chinese people is smaller than that of other countries. The abdominal aortic aneurysm (AAA) guideline might be developed based on the basic diameter to suit patients with AAA and a different basic abdominal aortic diameter. Artery diameter was increased by the age, and female patients have smaller diameter and larger arterial growth rate than male patients. Female and young patients with AAA may choose more oversize grafts for endovascular AAA repair.

Prevalence of Elective and Ruptured Abdominal Aortic Aneurysm Repairs by Age and Sex From 2003 to 2016 in Ontario, Canada

IMPORTANCE

Age and sex are important considerations in assessing and individualizing therapy for abdominal aortic aneurysm (AAA) repair.

OBJECTIVE

To determine the prevalence of open and endovascular elective AAA (EAAA) and ruptured AAA (RAAA) repair by age and sex.

DESIGN, SETTING, AND PARTICIPANTS

In this retrospective, population-based, cross-sectional, time-series analysis in Ontario, Canada, from April 1, 2003, to March 31, 2016, all patients undergoing AAA repair who were older than 39 years were included.

EXPOSURES

Elective AAA and RAAA repair with open surgical repair (OSR) or endovascular aortic repair (EVAR).

MAIN OUTCOMES AND MEASURES

Age- and sex-standardized rates of EAAA and RAAA repair with OSR and EVAR.

RESULTS

From 2003 to 2016, 19 489 EAAA repairs (12 232 [63%] OSR and 7257 [37%] EVAR) and 2732 RAAA repairs (2466 [90%] OSR and 266 [10%] EVAR) were identified. The mean (SD) age was 72.7 (8.1) years in the EAAA subgroup and 73.5 (8.9) years in the RAAA subgroup; 15 813 patients (81%) in the EAAA subgroup and 2178 (80%) in the RAAA subgroup were men. The rates of EAAA by age quintile and sex decreased over the study period except among patients older than 79 years (1.3 per 100 000 population in 2003 to 2.2 per 100 000 population in 2016; 70% increase; P < .001). The rates of elective OSR decreased across all age and sex subgroups (range, 38%-74% decrease; P ≤ .009 for all subgroups) except among patients older than 79 years (1.3 per 100 000 population at baseline to 0.56 per 100 000 population in the second quarter of 2016; 53% decrease; P = .05). The rates of elective EVAR significantly increased across all age and sex subgroups (range, 566%-1585% increase; P ≤ .04 for all subgroups). Elective EVAR became the dominant treatment approach for aneurysms in men around 2010, whereas it maintained parity among women in 2016. The RAAA repair rate decreased over the study period in all subgroups (range, 32%-91% decrease; P ≤ .001 for all subgroups), but the decrease was not significant among women (80% decrease; P = .08). Similarly, the rates of ruptured OSR decreased among all subgroups (range, 47%-91% decrease; P < .001), but the decrease was not significant among women (87% decrease; P = .54). Ruptured EVAR showed significant uptake in all subgroups.

CONCLUSIONS AND RELEVANCE

Among patients with AAA in Ontario, Canada, use of EVAR appeared to increase from 2003 to 2016, whereas OSR use appeared to decrease. These findings were most pronounced among elective procedures for men and older patients. The delayed increase in the use of EVAR among women may reflect continued anatomical constraints for women seeking elective repair.

Correcting for Body Surface Area Identifies the True Prevalence of Abdominal Aortic Aneurysm in Screened Women

OBJECTIVE

Recently, the prevalence of abdominal aortic aneurysm (AAA) using screening strategies based on elevated cardiovascular disease (CVD) risk was reported. AAA was defined as a diameter ≥30 mm, with prevalence of 6.1% and 1.8% in men and women respectively, consistent with the widely reported AAA predominant prevalence in males. Given the obvious differences in body size between sexes this study aimed to re-evaluate the expanded CVD risk based AAA screening dataset to determine the effect of body size on sex specific AAA prevalence.

METHODS

Absolute (26 and 30 mm) and relative (aortic size index [ASI] equals the maximum infrarenal aorta diameter (cm) divided by body surface area (m²), ASI ≥ 1.5) thresholds were used to assess targeted AAA screening groups (n = 4115) and compared with a self reported healthy elderly control group (n = 800).

RESULTS

Male AAA prevalence was the same using either the 30 mm or ASI ≥1.5 aneurysm definitions (5.7%). In females, AAA prevalence was significantly different between the 30 mm (2.4%) and ASI ≥ 1.5 (4.5%) or the 26 mm (4.4%) thresholds.

CONCLUSION

The results suggest the purported male predominance in AAA prevalence is primarily an artefact of body size differences. When aortic size is adjusted for body surface area there is only a modest sex difference in AAA prevalence. This observation has potential implications in the context of the ongoing discussion regarding AAA screening in women.

Characteristics of aorto-iliofemoral arterial tree according to aortic valve morphology in chinese patients considered for TAVR

To characterize the anatomy of aorto-iliofemoral arterial tree according to aortic valve phenotype by CT in patients referred for transcatheter aortic valve replacement (TAVR). We retrospectively enrolled 215 patients screened for TAVR who underwent CT. Dimensions, calcification, vascular tortuosity index score and other putative risk features of 13 different regions were evaluated for bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) morphology. The study consisted of 44% BAVs with younger age than TAVs. The dimensions of the annulus, sinus of Valsalva, ascending aorta and aortic arch were consistently larger in BAVs. The prevalence of calcification of aortic arch was significantly higher in TAVs even after adjustment for atherosclerotic risk factors. BAVs was associated with two-fold higher odds of having over I degree AA calcification (odds ratio 2.02; 95% CI 1.60-5.31; p < 0.001). The prevalence of severe iliac tortuosity was higher among BAVs (11.7 vs. 2.5%, p = 0.015). BAVs had a trend to more atheroma than TAVs in the abdominal aortic artery and iliofemoral artery. BAV anatomy is common in Chinese AS patients screened for TAVR. Aorto-iliofemoral pathology varies according to aortic valve phenotype, which may contribute to technical challenges in BAV vs. TAV anatomy and support the need for the integrated risk assessment for each valve phenotype.

The UK EndoVascular Aneurysm Repair (EVAR) randomised controlled trials: long-term follow-up and cost-effectiveness analysis

BACKGROUND

Short-term survival benefits of endovascular aneurysm repair (EVAR) compared with open repair (OR) of intact abdominal aortic aneurysms have been shown in randomised trials, but this early survival benefit is soon lost. Survival benefit of EVAR was unclear at follow-up to 10 years.

OBJECTIVE

To assess the long-term efficacy of EVAR against OR in patients deemed fit and suitable for both procedures (EVAR trial 1; EVAR-1); and against no intervention in patients unfit for OR (EVAR trial 2; EVAR-2). To appraise the long-term significance of type II endoleak and define criteria for intervention.

DESIGN

Two national, multicentre randomised controlled trials: EVAR-1 and EVAR-2.

SETTING

Patients were recruited from 37 hospitals in the UK between 1 September 1999 and 31 August 2004.

PARTICIPANTS

Men and women aged ≥ 60 years with an aneurysm of ≥ 5.5 cm (as identified by computed tomography scanning), anatomically suitable and fit for OR were randomly assigned 1 : 1 to either EVAR (n = 626) or OR (n = 626) in EVAR-1 using computer-generated sequences at the trial hub. Patients considered unfit were randomly assigned to EVAR (n = 197) or no intervention (n = 207) in EVAR-2. There was no blinding.

INTERVENTIONS

EVAR, OR or no intervention.

MAIN OUTCOME MEASURES

The primary end points were total and aneurysm-related mortality until mid-2015 for both trials. Secondary outcomes for EVAR-1 were reinterventions, costs and cost-effectiveness.

RESULTS

In EVAR-1, over a mean of 12.7 years (standard deviation 1.5 years; maximum 15.8 years), we recorded 9.3 deaths per 100 person-years in the EVAR group and 8.9 deaths per 100 person-years in the OR group [adjusted hazard ratio (HR) 1.11, 95% confidence interval (CI) 0.97 to 1.27; p = 0.14]. At 0-6 months after randomisation, patients in the EVAR group had a lower mortality (adjusted HR 0.61, 95% CI 0.37 to 1.02 for total mortality; HR 0.47, 95% CI 0.23 to 0.93 for aneurysm-related mortality; p = 0.031), but beyond 8 years of follow-up patients in the OR group had a significantly lower mortality (adjusted HR 1.25, 95% CI 1.00 to 1.56, p = 0.048 for total mortality; HR 5.82, 95% CI 1.64 to 20.65, p = 0.0064 for aneurysm-related mortality). The increased aneurysm-related mortality in the EVAR group after 8 years was mainly attributable to secondary aneurysm sac rupture, with increased cancer mortality also observed in the EVAR group. Overall, aneurysm reintervention rates were higher in the EVAR group than in the OR group, 4.1 and 1.7 per 100 person-years, respectively (p < 0.001), with reinterventions occurring throughout follow-up. The mean difference in costs over 14 years was £3798 (95% CI £2338 to £5258). Economic modelling based on the outcomes of the EVAR-1 trial showed that the cost per quality-adjusted life-year gained over the patient's lifetime exceeds conventional thresholds used in the UK. In EVAR-2, patients died at the same rate in both groups, but there was suggestion of lower aneurysm mortality in those who actually underwent EVAR. Type II endoleak itself is not associated with a higher rate of mortality.

LIMITATIONS

Devices used were implanted between 1999 and 2004. Newer devices might have better results. Later follow-up imaging declined, particularly for OR patients. Methodology to capture reinterventions changed mainly to record linkage through the Hospital Episode Statistics administrative data set from 2009.

CONCLUSIONS

EVAR has an early survival benefit but an inferior late survival benefit compared with OR, which needs to be addressed by lifelong surveillance of EVAR and reintervention if necessary. EVAR does not prolong life in patients unfit for OR. Type II endoleak alone is relatively benign.

FUTURE WORK

To find easier ways to monitor sac expansion to trigger timely reintervention.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN55703451.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and the results will be published in full in Health Technology Assessment; Vol. 22, No. 5. See the NIHR Journals Library website for further project information.

Abdominal aortic aneurysm: Sex differences

OBJECTIVE

Abdominal aortic aneurysm (AAA) predominantly affects an elderly male population. Even so, AAA appears more detrimental in women, who experience a higher risk of aneurysm rupture and a worse outcome after surgery than men. Why women are privileged from yet are worse off once affected has been attributed to an effect of sex hormones. This review summarizes the knowledge of sex differences in AAA and addresses the changes in the aneurysm wall from a gender perspective.

METHOD

Standard reporting guidelines set by the PRISMA Group were followed to identify studies examining AAA from a gender perspective. Relevant reports were identified using two electronic databases: PubMed and Web of Science. The systematic search was performed in two stages: firstly, using the terms AAA and gender/sex/women; and secondly, adding the terms "elastin", "collagen" and "vascular smooth muscle cells", in order to filter the search for studies relevant to our focus on the aneurysm wall.

CONCLUSION

Current studies support the theory that sex has an effect on aneurysm formation, yet are inconclusive about whether or not aneurysm formation is dependent on female/male sex hormones or a lack thereof. The studies in women are scarce and out of those most reports primarily address other end-points, which limit their ability to illuminate an effect of sex on aneurysm formation. The complexity of the human menstrual cycle and menopausal transition are difficult to mimic in animal models, which limit their applicability to AAA formation in humans.

Small infrarenal aortic diameter associated with lower-extremity peripheral artery disease in Chinese hypertensive adults

Several studies suggest that infrarenal aortic diameter is associated with lower-extremity peripheral artery disease (LE-PAD). However, data regarding the associations between infrarenal aortic diameter and LE-PAD are limited, especially in large sample populations and Asian or Chinese populations. Our analysis included 17279 Chinese hypertensive adults comprising 6590 men and 10689 women with a mean age of 64.74 ± 7.41 years. Participants were selected from 22693 candidates from two large population-based cohort-studies. The primary noninvasive test for diagnosis of LE-PAD is the ankle–brachial index (ABI) at rest and typically an ABI ≤ 0.90 is used to define LE-PAD. The prevalence of LE-PAD was found to significantly decrease as the aortic diameter increased according to the tertile of the aortic diameter. LE-PAD was significantly more prevalent in the lowest tertile (OR = 1.58, 95% CI = 1.29–1.94, p < 0.001) and similarly prevalent in the highest tertile (OR = 0.92, 95% CI = 0.73–1.16, p = 0.49) when compared with the median tertile. No significant interactions between the aortic diameter and any of the stratified variables were found (all p > 0.05). In conclusion, Small aortic diameter (as opposed to large aortic diameter) is significantly associated with LE-PAD in Chinese hypertensive adults.

Screening of siblings to patients with abdominal aortic aneurysms in Sweden

OBJECTIVE

The prevalence of Abdominal Aortic Aneurysm (AAA) is higher for First Degree Relatives to AAA-patients compared to the general population, regardless of sex. The prevalence of AAA is also higher in the North of Sweden compared to the Mid and South. A regional strong hereditary trait has been suggested as an explanation to this. The aim of this study was to investigate if siblings to AAA-patients in the North have a higher prevalence of AAA compared to siblings in the Mid-region.

DESIGN

Cohort study.

MATERIALS AND METHODS

All patients treated for AAA in a northern region (Norrbotten county, North) were screened for siblings. Consenting siblings, age 40-80, were examined (n = 379) with ultrasound. The results were compared to the previously published results of 150 ultrasound-screened siblings in the Mid-region (Stockholm county).

RESULTS

The male/female ratio in the sibling cohort was 48% vs 52%. The prevalence of AAA in siblings in the North was 37/379 (brothers 14%, sisters 6%). This was not different from the prevalence among the Mid-region siblings 16/150 (brothers 17%, sisters 6% (p = 0.75). The distribution of risk factors was similar in the two regions.

CONCLUSION

The results reinforce the importance of a more systematic approach towards selective screening of all siblings to AAA patients. Ultrasound should be performed in all eligible siblings, since the distribution of AAA is similar over regions. A correlation between the familial distribution and the reported high prevalence of AAA in general population in the North could not be shown.

Patients with abdominal aortic aneurysm have a high prevalence of popliteal artery aneurysms

Patients with abdominal aortic aneurysms (AAA) are more prone to develop popliteal artery aneurysms (PAA), but the prevalence is not well known. Our aim was to investigate the prevalence of PAA in patients with AAA, and to determine whether a certain risk factor profile is more commonly found in patients with concurrent aneurysms. All AAA patients (ICD code I71.3, I71.4) attending the outpatient clinic at the Karolinska University Hospital between 2011 and 2013 were included in the study cohort ( n=465); 48% (225) had been subjected to an ultrasound or computed tomography scan of their popliteal arteries. In these patients, three definitions of PAA were considered (⩾ 10.5, ⩾ 12, ⩾ 15 mm), although the overall analysis is based on PAA ⩾ 12 mm. The mean age was 70.7 years (SD 7.5), 89% were men, and the mean AAA diameter was 47 mm (SD 14). The prevalence of PAA was 19% ( n=43) by definition ⩾ 12 mm, and 11% ( n=25) with 15 mm. Claudication was more frequently found in AAA patients with PAA than patients without PAA. Sensitivity between clinical examination and radiology was 26%, and the specificity for clinical examination was 90%. In conclusion, owing to the high prevalence of PAA in AAA patients, described by us and others, the low cost and risks associated with ultrasound and the poor sensitivity at clinical examination, all women and men with AAA should undergo one radiological examination of their popliteal arteries.

Neutrophil Gelatinase Associated Lipocalin (NGAL) as a Biomarker. Does It Apply in Abdominal Aortic Aneurysms? A Review of Literature

Neutrophil gelatinase associated lipocalin (NGAL) as a protein derived from neutrophils has recently been the field of investigation in a wide range of diseases (renal disease, coronary artery disease, etc). The MEDLINE/PubMed database was searched for publications with the medical subject heading "NGAL" and keywords "Abdominal aortic aneurysm (AAA)," "biomarker," and "growth". We restricted our search to date. In this review, we included 38 articles and abstracts that were accessible and available in English. An effort to further explain the role of NGAL within AAA has been made. NGAL seems to be a hopeful marker for the pathogenesis and the progression of abdominal aortic aneurysms (AAAs), which has significant morbidity and mortality rates.

Thoracic and abdominal aortic diameters in a general population: MRI-based reference values and association with age and cardiovascular risk factors

OBJECTIVES

To generate reference values for thoracic and abdominal aortic diameters determined by magnetic resonance imaging (MRI) and analyse their association with cardiovascular risk factors in the general population.

METHODS

Data from participants (n = 1759) of the Study of Health in Pomerania were used for analysis in this study. MRI measurement of thoracic and abdominal aortic diameters was performed. Parameters for calculation of reference values according to age and sex analysis were provided. Multivariable linear regression models were used for determination of aortic diameter-related risk factors, including smoking, blood pressure (BP), high-density lipoprotein cholesterol (HDL-C).

RESULTS

For the ascending aorta (β = -0.049, p < 0.001), the aortic arch (β = -0.061, p < 0.001) and the subphrenic aorta (β = -0.018, p = 0.004), the body surface area (BSA)-adjusted diameters were lower in men. Multivariable-adjusted models revealed significant increases in BSA-adjusted diameters with age for all six aortic segments (p < 0.001). Consistent results for all segments were observed for the positive associations of diastolic BP (β = 0.001; 0.004) and HDL (β = 0.035; 0.087) with BSA-adjusted aortic diameters and for an inverse association of systolic BP (β = -0.001).

CONCLUSIONS

Some BSA-adjusted median aortic diameters are smaller in men than in women. All diameters increase with age, diastolic blood pressure and HDL-C and decrease as systolic BP increases.

KEY POINTS

• Median aortic diameter increases with age and diastolic blood pressure. • Median aortic diameter is larger in men than in women. • Some BSA-adjusted median aortic diameters are smaller in men than in women.

Techniques of imaging of the aorta and its first order branches by endoscopic ultrasound (with videos)

Endoscopic ultrasonography (EUS) is a useful modality for imaging of the blood vessels of the mediastinum and abdomen. The aorta acts as an important home base during EUS imaging. The aorta and its branches are accessible by standard angiographic methods, but endosonography also provides a unique opportunity to evaluate the aorta and its branches. This article describes the techniques of imaging of different part of the aorta by EUS.

Determinants and normal values of ascending aortic diameter by age, gender, and race/ethnicity in the Multi-Ethnic Study of Atherosclerosis (MESA)

PURPOSE

To determine the normal size and wall thickness of the ascending thoracic aorta (AA) and its relationship with cardiovascular risk factors in a large population-based study.

MATERIALS AND METHODS

The mean AA luminal diameter was measured in 3573 Multi-Ethnic Study of Atherosclerosis (MESA) participants (age: 45-84 years), using gradient echo phase contrast cine MRI. Multiple linear regression models were used to evaluate the associations between risk factors and AA diameter. The median and upper normal limit (95th percentile) was defined in a "healthy" subgroup as well as AA wall thickness.

RESULTS

The upper limits of body surface area indexed AA luminal diameter for age categories of 45-54, 55-64, 65-74, and 75-84 years are 21, 22, 22, and 28 mm/m(2) in women and 20, 21, 22, 23 mm/m(2) in men, respectively. The mean AA wall thickness was 2.8 mm. Age, gender, and body surface area were major determinants of AA luminal diameter (∼+1 mm/10 years; ∼+1.9 mm in men than women; ∼+1 mm/ 0.23 m(2) ; P < 0.001). The AA diameter in hypertensive subjects was +0.9 mm larger than in normotensives (P < 0.001).

CONCLUSION

AA diameter increases gradually with aging for both genders among all race/ethnicities. The normal value of AA diameter is provided.

Anatomical characteristics of the thoracic aortic arch in an Asian population

Background: Endovascular repair of the aortic arch is often unsatisfactory due to poor stent-vessel conformity and inadequate landing zones.

Objective: To study the anatomical characteristics of the aortic arch and provide basic information for the development of arch-specific endovascular devices.

Materials and methods: Three-dimensional models were reconstructed in Mimics (image segmentation software) from computed tomography aortograms of 120 elderly Asian patients, by manual segmentation. The centerline of each Three-dimensional aortic model was calculated using a repulsive force field method. Measurements of the aorta and supra-aortic branches were analyzed using Patran (finite-element software). A three-dimensional statistical aortic arch model was built using principal component analysis.

Results: The mean diameters of the ascending and descending aorta, and the origins of the innominate, left common carotid, and left subclavian artery were 39.4 ± 6.7, 34.5 ± 7.9, 18.0 ± 3.8, 12.6 ± 2.7, and 14.1 ± 2.5 mm, respectively. The length of the ascending aorta, innominate to left common carotid artery, and left common carotid to left subclavian artery were 62.6 ± 11.4, 12.0 ± 5.6, and 18.7 ± 5.6 mm along the centerline. The mean angle of curvature was 103.8 ± 25 degrees. Principal component analysis of the three-dimensional centerlines derived 3 main modes of variation, which account for 61% of the overall shape range.

Conclusion: Aortic arch anatomical information from an elderly Asian population can be useful for the development of future endovascular devices.

Thoracic and abdominal aortic diameter measurement by MRI using plain axial volumetric interpolated breath-hold examination in epidemiologic research: a validation study

RATIONALE AND OBJECTIVES

This study evaluates the validity and reliability of measuring the diameters of the thoracic and abdominal aorta from plain volumetric interpolated breath-hold examination (VIBE) images.

MATERIALS AND METHODS

The study included 50 male subjects from the population-based Study of Health in Pomerania. They underwent imaging of the thoracic and abdominal aorta at 1.5 Tesla using a contrast-enhanced magnetic resonance angiography (CE-MRA) and plain VIBE sequence. Diameters were measured at five predefined anatomic sites from reformatted orthogonal CE-MRA images and axial plain VIBE images. The measurements were validated using Pearson correlation and Bland-Altman analysis. The Bland-Altman method was also used to assess reliability.

RESULTS

Comparison of the diameters measured from CE-MRA and VIBE images revealed strong correlation for the ascending, descending, suprarenal, and infrarenal aorta with r = 0.95 (P < .0001), r = 0.88 (P < .0001), 0.92 (P < .0001), and 0.87 (P < .0001), respectively. Measurement for the aortic arch was moderately correlated with r = 0.78 (P < .0001). Mean bias did not exceed 0.1 cm (6%). The 95% limits of agreement (LOA) were less than 0.5 cm (15%). Intra- and interobserver agreement showed a mean bias of less than 2%; the 95% LOA were less than 11%.

CONCLUSIONS

Axial measurement of the diameters of the thoracic and abdominal aorta using a plain axial VIBE sequence is highly valid and reliable, making it suitable for use in epidemiologic research.

ACR Appropriateness Criteria® pulsatile abdominal mass, suspected abdominal aortic aneurysm

Clinical palpation of a pulsating abdominal mass alerts the clinician to the presence of a possible abdominal aortic aneurysm (AAA). Generally an arterial aneurysm is defined as a localized arterial dilatation ≥50% greater than the normal diameter. Imaging studies are important in diagnosing the cause of a pulsatile abdominal mass and, if an AAA is found, in determining its size and involvement of abdominal branches. Ultrasound (US) is the initial imaging modality of choice when a pulsatile abdominal mass is present. Noncontrast computed tomography (CT) may be substituted in patients for whom US is not suitable. When aneurysms have reached the size threshold for intervention or are clinically symptomatic, contrast-enhanced multidetector CT angiography (CTA) is the best diagnostic and preintervention planning study, accurately delineating the location, size, and extent of aneurysm and the involvement of branch vessels. Magnetic resonance angiography (MRA) may be substituted if CT cannot be performed. Catheter arteriography has some utility in patients with significant contraindications to both CTA and MRA. The American College of Radiology Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.