Final follow-up of the Multicentre Aneurysm Screening Study (MASS) randomized trial of abdominal aortic aneurysm screening

Opportunistic Ultrasound Screening for Abdominal Aortic Aneurysm

Objective: In patients with abdominal aortic aneurysm (AAA), early detection and optimal elective treatment before rupture are desirable. In the absence of an established public screening system, opportunistic screening during ultrasound examination for another purpose might be efficacious. The aim of this study was to evaluate the efficacy of opportunistic screening for AAA. Methods: This prospective multicenter observational study enrolled patients who were scheduled to undergo ultrasound for reasons other than AAA. After the ultrasound for the original purpose, evaluation of the abdominal aorta was added. If the abdominal aorta was clear enough for measurement, its diameter and shape were recorded. Furthermore, information on comorbidities was collected for each patient. Results: A total of 10325 patients (echocardiography: 6150; abdominal ultrasound: 4162) from 16 institutions were enrolled. The abdominal aorta was well visualized in 92.9% of patients who underwent echocardiography. Among 9791 patients, AAA was diagnosed in 122 (1.3%) (107 fusiform and 15 saccular), with a diameter range of 30-63 mm. The diagnostic rate increased with age. On multivariate analysis, older age, male sex, coronary artery disease, peripheral arterial disease, and smoking habituation were the risk factors for AAA. Conclusion: Opportunistic screening for AAA was efficacious.

Computed Tomography Angiography for Aortic Diseases

Aortic pathologies encompass a heterogeneous group of disorders, including acute aortic syndrome, traumatic aortic injury , aneurysm, aortitis, and atherosclerosis. The clinical manifestations of these disorders can be varied and non-specific, ranging from acute presentations in the emergency department to chronic incidental findings in an outpatient setting. Given the non-specific nature of their clinical presentations, the reliance on non-invasive imaging for screening, definitive diagnosis, therapeutic strategy planning, and post-intervention surveillance has become paramount. Commonly used imaging modalities include ultrasound, computed tomography (CT), and MR imaging. Among these modalities, computed tomography angiography (CTA) has emerged as a first-line imaging modality owing to its excellent anatomic detail, widespread availability, established imaging protocols, evidence-proven indications, and rapid acquisition time.

One-time screening for abdominal aortic aneurysm in Ontario, Canada: a model-based cost-utility analysis

BACKGROUND

Screening programs for abdominal aortic aneurysm (AAA) are not available in Canada. We sought to determine the effectiveness and costutility of AAA screening in Ontario.

METHODS

We compared one-time ultrasonography-based AAA screening for people aged 65 years to no screening using a fully probabilistic Markov model with a lifetime horizon. We estimated life-years, quality-adjusted life-years (QALYs), AAA-related deaths, number needed to screen to prevent 1 AAA-related death and costs (in Canadian dollars) from the perspective of the Ontario Ministry of Health. We retrieved model inputs from literature, Statistics Canada, and the Ontario Case Costing Initiative.

RESULTS

Screening reduced AAA-related deaths by 84.9% among males and 81.0% among females. Compared with no screening, screening resulted in 0.04 (18.96 v. 18.92) additional life-years and 0.04 (14.95 v. 14.91) additional QALYs at an incremental cost of $80 per person among males. Among females, screening resulted in 0.02 (21.25 v. 21.23) additional life-years and 0.01 (16.20 v. 16.19) additional QALYs at an incremental cost of $11 per person. At a willingness-to-pay of $50 000 per year, screening was cost-effective in 84% (males) and 90% (females) of model iterations. Screening was increasingly cost-effective with higher AAA prevalence.

INTERPRETATION

Screening for AAA among people aged 65 years in Ontario was associated with fewer AAA-related deaths and favourable cost-effectiveness. To maximize QALY gains per dollar spent and AAA-related deaths prevented, AAA screening programs should be designed to ensure that populations with high prevalence of AAA participate.

Automated detection of incidental abdominal aortic aneurysms on computed tomography

PURPOSE

To detect and assess abdominal aortic aneurysms (AAAs) on CT in a large asymptomatic adult patient population using fully-automated deep learning software.

MATERIALS AND METHODS

The abdominal aorta was segmented using a fully-automated deep learning model trained on 66 manually-segmented abdominal CT scans from two datasets. The axial diameters of the segmented aorta were extracted to detect the presence of AAAs-maximum axial aortic diameter greater than 3 cm were labeled as AAA positive. The trained system was then externally-validated on CT colonography scans of 9172 asymptomatic outpatients (mean age, 57 years) referred for colorectal cancer screening. Using a previously-validated automated calcified atherosclerotic plaque detector, we correlated abdominal aortic Agatston and volume scores with the presence of AAA.

RESULTS

The deep learning software detected AAA on the external validation dataset with a sensitivity, specificity, and AUC of 96%, (95% CI 89%, 100%), 96% (96%, 97%), and 99% (98%, 99%) respectively. The Agatston and volume scores of reported AAA-positive cases were statistically significantly greater than those of reported AAA-negative cases (p < 0.0001). Using plaque alone as a AAA detector, at a threshold Agatston score of 2871, the sensitivity and specificity were 84% (73%, 94%) and 87% (86%, 87%), respectively.

CONCLUSION

Fully-automated detection and assessment of AAA on CT is feasible and accurate. There was a strong statistical association between the presence of AAA and the quantity of abdominal aortic calcified atherosclerotic plaque.

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

Prevalence of abdominal aortic aneurysm (AAA) in first-degree relatives: detecting AAA in adult offspring of AAA patients

BACKGROUND

First-degree relatives of patients with abdominal aortic aneurysm (AAA) may have an increased risk of developing the disease. The primary aim was to report the prevalence of AAA in adult male and female offspring of patients with AAA. The secondary aim was to explore the efficiency of a registry-based detection route, and the third aim was to report contemporary prevalence in the population.

METHODS

Adult offspring of individuals with AAA and matched controls were identified through national registries. The examination included questionnaires and ultrasound examinations of the infrarenal aorta. Aortic pathology was defined as an aortic diameter ≥25 mm, AAA ≥30 mm.

RESULTS

The participation rate among male and female adult offspring was 64% (350/543) and 69% (402/583), respectively. A lower participation rate was found in male and female controls (51% and 52%). No difference in prevalence of AAA was observed between male adult offspring and controls (0.9%, c.i. 0.2 to 2.3%) or in the female population (prevalence of 0.2% in adult offspring and controls). Aortic pathology and previously diagnosed AAA were detected in 5.3% (c.i. 3.3 to 8.0%) of male adult offspring and 2.3% (c.i. 1.1 to 4.2%) in controls. Aortic pathology was more prevalent among adult offspring of females with AAA.

CONCLUSION

The prevalence of AAA in the general population is low, but aortic pathology is notably higher among male first-degree relatives. Increased awareness should be directed towards individuals with a possible hereditary predisposition, particularly offspring of females with AAA and older smokers. Risk factor-based targeted screening of adult offspring of patients with AAA after registry-based detection should be further explored.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT4623268.

Association between the non-HDL-cholesterol to HDL- cholesterol ratio and abdominal aortic aneurysm from a Chinese screening program

BACKGROUND

Abdominal aortic aneurysms (AAAs) can result in high mortality upon rupture but are usually undiagnosed because of the absence of symptoms in the early stage. Ultrasound screening is regarded as an impactful way to prevent the AAA-related death but cannot be performed efficiently; therefore, a target population, especially in Asia, for this procedure is lacking. Additionally, although dyslipidaemia and atherosclerosis are associated with AAA. However, it remains undetermined whether the non-high-density lipoprotein-cholesterol to high-density lipoprotein-cholesterol ratio (NHHR) is associated with AAA. Therefore, this study was aimed at examining whether NHHR is associated with AAA.

METHOD

A total of 9559 participants who underwent AAA screening at Guangdong Provincial People's Hospital and through screening in two communities in Dongguan, from June 2019 to June 2021 joined in this screening program. The diagnosis of AAA was confirmed by the ultrasound examination of the abdominal aorta rather than any known or suspected AAA. Clinical and laboratory data of participants were collected. The participants were separated into a normal group and an AAA group according to the abdominal aortic status. To eliminate confounding factors, a propensity score matching (PSM) approach was utilized. The independent relationship between NHHR and AAA was assessed through the utilization of multivariable logistic regression analysis. In addition, internal consistency was evaluated through subgroup analysis, which controlled for significant risk factors.

RESULTS

Of all the participants, 219 (2.29%) participants were diagnosed with AAA. A significant elevation in NHHR was identified in the AAA group when contrasted with that in the normal group (P < 0.001). As demonstrated by the results of the multivariable logistic regression analysis, AAA was independently associated with NHHR before (odds ratio [OR], 1.440, P < 0.001) and after PSM (OR, 1.515, P < 0.001). Significant extension was observed in the areas under the receiver operating characteristic curves (AUROCs) of NHHR compared to those of single lipid parameters before and after PSM. An accordant association between NHHR and AAA in different subgroups was demonstrated by subgroup analysis.

CONCLUSION

In the Chinese population, there is an independent association between NHHR and AAA. NHHR might be propitious to distinguish individuals with high risk of AAA.

Establishment of a clinical nurse specialist-led, virtual aneurysm surveillance clinic

BACKGROUND

The COVID-19 pandemic has necessitated significant changes to the manner in which healthcare is delivered. Chief among these has been the need to rapidly adopt virtual, or telephone clinics as a means of reducing unnecessary patient exposure to hospitals and clinical care settings. We were greatly aided in our adoption of virtual clinics by our experience in the establishment and maintenance of a Clinical Nurse Specialist-led, virtual clinic for both abdominal aortic (AAA) and extra-aortic aneurysm (EAA) surveillance within our department since 2016. Patients undergoing surveillance for abdominal aortic aneurysm (AAA) require frequent and lifelong clinical review. Previous studies have shown that post-operative surveillance in particular is critical in prolonging survival in AAA patients and in the early detection of late complications particularly following endovascular repair (EVAR). Poor compliance with EVAR surveillance has been shown to result in worse outcomes.

AIM

The aim of this study was to evaluate the success of a nurse-led virtual clinic programme in terms of the safe management of patients undergoing AAA surveillance in a nurse-led virtual clinic.

RESULTS

Over the course of the 4-year period from 2016 to 2019, 1352 patients were enrolled in the virtual aneurysm surveillance clinic. The majority of patients each year were male, ranging from 78.2% in 2016 to 85.2% in 2017. The majority of patients encountered the service owing to pre-operative surveillance of an AAA, with this group comprising at least 65% of the total cohort of patients each year.Over the course of the 4-year period of the virtual clinic there were 1466 patient encounters. Each ambulatory day care centre (ADCC) attendance normally costs the hospital €149. Therefore, a total saving of €218,434 resulted from this initiative alone. No patient presented as an emergency with a ruptured aneurysm during the time period studied.

CONCLUSION

Patients with AAA can be safely kept under surveillance in a nurse-led virtual clinic. Our experience with this model of care proved to be particularly advantageous during the period of the early COVID-19 pandemic.

Eleven-Year Outcomes of a Screening Project for Abdominal Aortic Aneurysm (AAA) in 65-Year-Old Men

Objective

Since 2011, the Department of Vascular Surgery at Oslo University Hospital has offered screening for abdominal aortic aneurysm (AAA) to 65-year-old men living in Oslo, Norway. The aim of this study was to evaluate the effect of the screening project on AAA-related mortality and rupture and repair rates in the screened population.

Methods

This cohort study included men that participated in AAA screening at the Department of Vascular Surgery at Oslo University Hospital in the period May 2011 to September 2019. All men with screen-detected AAA (aortic diameter ≥30 mm) and subaneurysmal aortic dilatation (aortic diameter 25-29 mm) were included. A stratified (1:1 with the subaneurysm group), randomized selection of men with normal aortic diameter (<25 mm) upon screening was also included. The follow-up data on events (ruptures, repairs, and deaths) after screening were collected retrospectively from patient electronic medical records at Oslo University Hospital, the National Population Register and the Norwegian Cause of Death Registry (CoDR).

Results

In total, 2048 men were included, with a median follow-up time of 7.1 years (IQR 3.8). Among men with screen-detected AAA, 0.6% died of AAA-related causes (0.9 AAA-related deaths per 1000 person-years). The rupture rate was 0.3% among men with screen-detected AAA or subaneurysmal aortic dilatation, giving an incidence of 0.5 ruptures per 1000 person-years. The overall repair rate in the AAA group was 20.6% (36.1 repairs per 1000 person-years) and 0.6% (0.9 repairs per 1000 person-years) in the subaneurysm group.

Conclusion

In a population screened for AAA, the incidence of rupture and the AAA-related mortality was very low. Almost one-fifth of the participants with screen-detected AAA underwent elective repair, representing a group that might have presented with rupture if untreated. These results indicate that screening is valuable in preventing AAA rupture and AAA-related mortality.

Evaluation of Point-of-Care Ultrasound Training for Family Physicians Using Teleultrasound

BACKGROUND AND OBJECTIVES

The goal of this study was to assess family physicians' change in knowledge and ability to perform abdominal aorta ultrasound after implementation of a novel teleultrasound curriculum.

METHODS

This was a prospective, observational study conducted at a single academic institution. Family physicians completed a preassessment, test, and objective structured clinical evaluation (OSCE). Physicians then individually completed a standard curriculum consisting of online content and an hour-long, hands-on training session on abdominal aorta ultrasound using teleultrasound technology. Physicians then performed a minimum of 10 independent examinations over a period of 8 weeks. After physicians completed the training curriculum and 10 independent scans, we administered a postassessment, test, and OSCE. We analyzed differences between pre- and postcurriculum responses using Fisher exact and Wilcoxon signed rank tests.

RESULTS

Thirteen family physicians completed the curriculum. Comparing pre- to postcurriculum responses, we found significant reductions in barriers to using aorta POCUS and improved confidence in using, obtaining, and interpreting aorta POCUS (P<0.01). Knowledge improved from a median score of 70% to 90% (P<0.01), and OSCE scores improved from a median of 80% to 100% (P=0.012). Overall, 211 aorta ultrasound examinations were independently acquired with a median image quality of 4 (scale 1 to 4).

CONCLUSIONS

After an 8-week teleultrasound curriculum, family physicians with minimal experience with POCUS showed improved knowledge and psychomotor skill in abdominal aorta POCUS.

Editor's Choice - Prevalence of Peripheral Arterial Disease, Abdominal Aortic Aneurysm, and Risk Factors in the Hamburg City Health Study: A Cross Sectional Analysis

OBJECTIVE

There is a paucity of current figures on the prevalence of carotid and lower extremity peripheral arterial disease (PAD) and abdominal aortic aneurysm (AAA) as well as the associated cardiovascular risk factors to support considerations on screening programmes.

METHODS

In the population based Hamburg City Health Study, participants between 45 and 74 years were randomly recruited. In the current cross sectional analysis of the first 10 000 participants enrolled between February 2016 and November 2018, the prevalence of carotid artery disease (intima-media thickness ≥ 1 mm), lower extremity PAD (ankle brachial index ≤ 0.9), and AAA (aortic diameter ≥ 30 mm) was determined. Multivariable logistic regression models were applied to determine the association between vascular diseases and risk factors. To account for missing values, multiple imputation was performed.

RESULTS

A total of 10 000 participants were analysed (51.1% females, median age 63 years, median body mass index 26.1 kg/m2). In medians, the intima media thickness was 0.74 mm (interquartile range [IQR] 0.65 - 0.84), the ankle brachial index 1.04 (IQR 0.95 - 1.13), and the aortic diameter 17.8 mm (IQR 16.1 - 19.6). Concerning risk factors, 64% self reported any smoking, 39% hypertension, 5% coronary artery disease, 3% congestive heart failure, 5% atrial fibrillation, and 3% history of stroke or myocardial infarction, respectively. In males, the prevalence of carotid artery disease, lower extremity PAD, and AAA were 35.3%, 22.7%, and 1.3%, respectively, and in females, 23.4%, 24.8%, and 0.2%, respectively. Higher age and current smoking were likewise associated with higher prevalence while the impact of variables varied widely.

CONCLUSION

In this large population based cohort study of 10 000 subjects from Hamburg, Germany, a strikingly high prevalence of PAD was revealed. Almost 45% suffered from any index disease, while AAA was only diagnosed in 1.3% of males and 0.2% of females. The high prevalence of atherosclerotic disease and associated cardiovascular risk factors underline that it is essential to increase awareness and fuel efforts for secondary prevention.

Why do guidelines recommend screening for abdominal aortic aneurysms, but not for asymptomatic carotid stenosis? A plea for a randomized controlled trial

BACKGROUND

Current guidelines do not recommend screening for asymptomatic carotid artery stenosis (AsxCS). The rationale behind this recommendation is that detection of AsxCS may lead to an unnecessary carotid intervention. In contrast, screening for abdominal aortic aneurysms is strongly recommended.

METHODS

A critical analysis of the literature was performed to evaluate the implications of detecting AsxCS.

RESULTS

Patients with AsxCS are at high risk for future stroke, myocardial infarction and vascular death. Population-wide screening for AsxCS should not be recommended. Additionally, screening of high-risk individuals for AsxCS with the purpose of identifying candidates for a carotid intervention is inappropriate. Instead, selective screening for AsxCS should be considered and should be viewed as an opportunity to identify individuals at high risk for atherosclerotic cardiovascular disease and future cardiovascular events for the timely initiation of intensive medical therapy and risk factor modification.

CONCLUSIONS

Although mass screening should not be recommended, there are several arguments suggesting that selective screening for AsxCS should be considered. The rationale supporting such selective screening is to optimize risk factor control and to initiate intensive medical therapy for prevention of future cardiovascular events, rather than to identify candidates for an intervention.

IL-1 in Abdominal Aortic Aneurysms

Abdominal Aortic Aneurysms (AAA) remain a clinically devastating disease with no effective medical treatment therapy. AAAs are characterized by immune cell infiltration, smooth muscle cell apoptosis, and extracellular matrix degradation. Interleukin-1 (IL-1) has been shown to play role in AAA associated inflammation through immune cell recruitment and activation, endothelial dysfunction, production of reactive oxygen species (ROS), and regulation of transcription factors of additional inflammatory mediators. In this review, we will discuss the principles of IL-1 signaling, its role in AAA specific inflammation, and regulators of IL-1 signaling. Additionally, we will discuss the influence of genetic and pharmacological inhibitors of IL-1 on experimental AAAs. Evidence suggests that IL-1 may prove to be a potential therapeutic target in the management of AAA disease.

Computed Tomography Angiography Markers and Intraluminal Thrombus Morphology as Predictors of Abdominal Aortic Aneurysm Rupture

Background: Abdominal aortic aneurysm (AAA) is a complex vascular disease characterized by progressive and irreversible local dilatation of the aortic wall. Currently, the indication for repair is linked to the transverse diameter of the abdominal aorta, using computed tomography angiography imagery, which is one of the most used markers for aneurysmal growth. This study aims to verify the predictive role of imaging markers and underlying risk factors in AAA rupture. Methods: The present study was designed as an observational, analytical, retrospective cohort study and included 220 patients over 18 years of age with a diagnosis of AAA, confirmed by computed tomography angiography (CTA), admitted to Vascular Surgery Clinic of Mures County Emergency Hospital in Targu Mures, Romania, between January 2018 and September 2022. Results: Patients with a ruptured AAA had higher incidences of AH (p = 0.006), IHD (p = 0.001), AF (p < 0.0001), and MI (p < 0.0001), and higher incidences of all risk factors (tobacco (p = 0.001), obesity (p = 0.02), and dyslipidemia (p < 0.0001)). Multivariate analysis showed that a high baseline value of all imaging ratios markers was a strong independent predictor of AAA rupture (for all p < 0.0001). Moreover, a higher baseline value of DAmax (OR:3.91; p = 0.001), SAmax (OR:7.21; p < 0.001), and SLumenmax (OR:34.61; p < 0.001), as well as lower baseline values of DArenal (OR:7.09; p < 0.001), DACT (OR:12.71; p < 0.001), DAfemoral (OR:2.56; p = 0.005), SArenal (OR:4.56; p < 0.001), SACT (OR:3.81; p < 0.001), and SThrombusmax (OR:5.27; p < 0.001) were independent predictors of AAA rupture. In addition, AH (OR:3.33; p = 0.02), MI (OR:3.06; p = 0.002), and PAD (OR:2.71; p = 0.004) were all independent predictors of AAA rupture. In contrast, higher baseline values of SAmax/Lumenmax (OR:0.13; p < 0.001) and ezetimibe (OR:0.45; p = 0.03) were protective factors against AAA rupture. Conclusions: According to our findings, a higher baseline value of all imaging markers ratios at CTA strongly predicts AAA rupture and AH, MI, and PAD highly predicted the risk of rupture in AAA patients. Furthermore, the diameter of the abdominal aorta at different levels has better accuracy and a higher predictive role of rupture than the maximal diameter of AAA.

The treatment choices of abdominal aortic aneurysm patients in China in the era of value-based healthcare

Background

Endovascular aneurysm repair (EVAR) is often seen as the first choice treatment for patients with abdominal aortic aneurysm (AAA), particularly high-risk patients, yet the long-term survival rate and improvement in quality of life are still unclear. In order to seek the value of EVAR to the entire healthcare field, we conducted a retrospective study to evaluate whether the improvement EVAR can truly bring to the quality of medical care in the era of value-based healthcare.

Methods

We included AAA patients who underwent surgical treatment in the Department of Vascular Surgery, First Hospital of China Medical University, from January 1, 2004, to December 31, 2019 and evaluated surgery procedure data, short-term and long-term mortality, complications, prognoses, and medical costs.

Results

We analyzed 507 patients with AAA who underwent open repair (n = 232) or EVAR (n = 275) over a 15-year period. The operative time, blood loss, blood transfusion rate, and postoperative length of hospital stay of the EVAR group is significantly lower than which of the open repair group. Meanwhile, neither short-term nor long-term mortality rates shows significant differences between the two groups. On the other hand, the complication rate of the EVAR group was significantly higher than that of the open repair group. Lastly, the total cost of EVAR was significantly higher than that of open repair.

Conclusion

Existing evidence suggests that EVAR improves neither short-term nor long-term survival rate compared with open surgery. In contrast, the complication rate and the reintervention rate in the EVAR group were higher than those in the open surgery group. Moreover, the cost of EVAR and that paid by medical insurance were higher than those for open surgery. For patients with a long-life expectancy, in order to ensure that patients receive appropriate and effective care, surgeons should choose a suitable method that considers both the quality of medical care as well as the expense accordingly.

NADPH Oxidases in Aortic Aneurysms

Abdominal aortic aneurysms (AAAs) are a progressive dilation of the infrarenal aorta and are characterized by inflammatory cell infiltration, smooth muscle cell migration and proliferation, and degradation of the extracellular matrix. Oxidative stress and the production of reactive oxygen species (ROS) have been shown to play roles in inflammatory cell infiltration, and smooth muscle cell migration and apoptosis in AAAs. In this review, we discuss the principles of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase/NOX) signaling and activation. We also discuss the effects of some of the major mediators of NOX signaling in AAAs. Separately, we also discuss the influence of genetic or pharmacologic inhibitors of NADPH oxidases on experimental pre-clinical AAAs. Experimental evidence suggests that NADPH oxidases may be a promising future therapeutic target for developing pharmacologic treatment strategies for halting AAA progression or rupture prevention in the management of clinical AAAs.

Endovascular Abdominal Aortic Aneurysm Repair: Overview of Current Guidance, Strategies, and New Technologies, Perspectives from the United Kingdom

Endovascular aortic aneurysm repair has changed the management of patients affected by this condition, offering a minimally invasive solution with satisfactory outcomes. Constant evolution of this technology has expanded the use of endovascular devices to more complex cases. The purpose of this review article is to describe the current strategies, guidance, and technologies in this field, with a particular focus on practices in the United Kingdom.

Editor's Choice - Risk of Rupture and All Cause Mortality of Abdominal Aortic Ectasia: A Systematic Review and Meta-Analysis

OBJECTIVE

To clarify the natural history of abdominal aortic ectasia (AAE) measuring 25 - 29 mm in maximum diameter, and to determine the optimal follow up based on the growth, risk of rupture, and overall mortality of AAE.

DATA SOURCES

MEDLINE, Web of Science Core Collection, and Google Scholar.

REVIEW METHODS

This was a systematic review and meta-analysis of AAE in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. MEDLINE, Web of Science Core Collection, and Google Scholar were searched, with the help of a health sciences librarian, up to 11 August 2021. Studies with longitudinal outcomes of AAE (prevalence, annual growth rate, aneurysmal enlargement, rupture, aneurysm related death, and all cause mortality) were included. Meta-analyses were conducted with a random effects model RESULTS: Twelve studies describing a total of 8 369 patients were eligible. The prevalence at population based settings was 3.2% (95% confidence interval [CI] 2.4 - 4.0); annual growth rate was 0.82 mm/year (95% CI 0.20 - 1.45). The estimated risks of aortic diameters exceeding 30 mm and 55 mm in five years were 45.0% (95% CI 28.5 - 61.5) and 0.3% (95% CI 0 - 0.6) respectively, while those beyond five years were 70.2% (95% CI 46.9 - 93.6) and 5.2% (95% CI 2.2 - 8.2). The rates of rupture and aneurysm related death were minimal until five years (0.1% and 0.1%, respectively) and beyond (0.4% and 0.2%, respectively). Overall mortality was 7.5% (95% CI 3.9 - 11.0) and 17.3% (95% CI 9.5 - 25.1) up to and beyond five years. Overall mortality from three studies showed no statistical difference between AAE and aneurysms (hazard ratio 0.62, 95% CI 0.32 - 1.21; p = .16). Cancer (35.0%) and cardiovascular diseases (31.9%) were major causes of death.

CONCLUSION

AAE carries minimal risk of aneurysm related lethal events during the first five years, but a similar overall mortality risk as abdominal aortic aneurysm. Cancer and cardiovascular diseases are leading causes of death in patients with AAE.

Molecular Imaging of Aortic Aneurysm and Its Translational Power for Clinical Risk Assessment

Aortic aneurysms (AAs) are dilations of the aorta, that are often fatal upon rupture. Diagnostic radiological techniques such as ultrasound (US), magnetic resonance imaging (MRI), and computed tomography (CT) are currently used in clinical practice for early diagnosis as well as clinical follow-up for preemptive surgery of AA and prevention of rupture. However, the contemporary imaging-based risk prediction of aneurysm enlargement or life-threatening aneurysm-rupture remains limited as these are restricted to visual parameters which fail to provide a personalized risk assessment. Therefore, new insights into early diagnostic approaches to detect AA and therefore to prevent aneurysm-rupture are crucial. Multiple new techniques are developed to obtain a more accurate understanding of the biological processes and pathological alterations at a (micro)structural and molecular level of aortic degeneration. Advanced anatomical imaging combined with molecular imaging, such as molecular MRI, or positron emission tomography (PET)/CT provides novel diagnostic approaches for in vivo visualization of targeted biomarkers. This will aid in the understanding of aortic aneurysm disease pathogenesis and insight into the pathways involved, and will thus facilitate early diagnostic analysis of aneurysmal disease. In this study, we reviewed these molecular imaging modalities and their association with aneurysm growth and/or rupture risk and their limitations. Furthermore, we outline recent pre-clinical and clinical developments in molecular imaging of AA and provide future perspectives based on the advancements made within the field. Within the vastness of pre-clinical markers that have been studied in mice, molecular imaging targets such as elastin/collagen, albumin, matrix metalloproteinases and immune cells demonstrate promising results regarding rupture risk assessment within the pre-clinical setting. Subsequently, these markers hold potential as a future diagnosticum of clinical AA assessment. However currently, clinical translation of molecular imaging is still at the onset. Future human trials are required to assess the effectivity of potentially viable molecular markers with various imaging modalities for clinical rupture risk assessment.

Overview of screening eligibility in patients undergoing ruptured AAA repair from 2003 to 2019 in the Vascular Quality Initiative

OBJECTIVE

Although efforts such as the Screening Abdominal Aortic Aneurysms Very Efficiently (SAAAVE) Act have improved access to abdominal aortic aneurysm (AAA) screening, certain high-risk populations are currently excluded from the guidelines yet may benefit from screening. We therefore examined all patients who underwent repair of ruptured AAA (rAAA) to characterize those who are ineligible for screening under current guidelines and evaluate the potential impact of these restrictions on their disease.

METHODS

We identified patients undergoing rAAA repair in the Vascular Quality Initiative (VQI) database between 2003 and 2019. These patients were stratified by AAA screening eligibility according to the Centers for Medicare and Medicaid reimbursement guidelines. We then described baseline characteristics to identify high-risk features of these cohorts. Groups with disproportionate representation in the screening-ineligible cohort were identified as potential targets of screening expansion. Trends over time in screening eligibility and the proportion of AAA repairs performed for rAAA were also analyzed.

RESULTS

A total of 5340 patients underwent rAAA repair. The majority (66%) were screening-ineligible. When characterizing the screening-ineligible group by sex and risk factors (smoking history or family history of AAA), the largest contributors to screening ineligibility were males less than 65 years of age with a smoking history or family history of AAA (25%), males greater than 75 years of age with a smoking history (25%), and females older than 65 years of age with a smoking history (19%). In comparison with rAAAs prior to implementation of the SAAAVE act, the proportion of AAA repair performed for rupture among males undergoing AAA repair in the VQI decreased from 12% to 8% (P < .001), whereas in females, there was no change (P = .990). There was no statically significant difference in screening eligibility for either males (P = .762) or females (P = .335).

CONCLUSIONS

Most patients who underwent rAAA repair were ineligible for initial AAA screening or aged out of the screening window. Furthermore, rAAA rates and screening ineligibility have not improved as much as expected since the passage of the SAAAVE Act. Our data suggest that three high-risk populations may benefit from expansion of AAA screening guidelines: males with a smoking history or family history of AAA between ages 55 and 64 years, female smokers older than 65 years, and male smokers older than 75 years who are otherwise in good health. Increased efforts to screen these high-risk populations may increase elective AAA repair and minimize the morbidity and mortality associated with rAAAs.

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.

The U.S. Preventive Services Task Force Abdominal Aortic Aneurysm Screening Guidelines Negligibly Impacted Repair Rates in Male Never-Smokers and Female Smokers

OBJECTIVE

In 2014, in addition to male smokers aged 65-75, the U.S. Preventive Services Task Force (USPSTF) recommended abdominal aortic aneurysm (AAA) screening for male never-smokers aged 65-75 with cardiovascular risk factors (Grade C). The USPSTF evolved from a negative to neutral position on screening for female smokers aged 65-75 (Grade I). We sought to determine whether 2014 guidelines resulted in more AAA repairs in these populations.

METHODS

We queried the Vascular Quality Initiative national database (2013-2018) for elective endovascular aortic repairs and open aortic repairs. We implemented difference-in-differences (DID) analysis, a causal inference technique that adjusts for secular time trends, to isolate changes in repair numbers due to the 2014 USPSTF guidelines. Our DID models compared changes in repair numbers in patient groups targeted by the USPSTF updates (intervention group) to those in unaffected, older patient groups (control), before and after 2014. The first model compared changes in repair numbers between male never-smokers aged 65-75 (intervention group) and 76-85 (control). The second model compared repair numbers between female smokers aged 65-75 (intervention group) and 76-85 (control).

RESULTS

There was no significant change in male never-smokers (n=1,295) aged 65-75 (42%) vs. 76-85 (58%) undergoing AAA repairs after guideline updates, averaged over 4.5 years (+2.4 percentage points; 95% Confidence Interval [CI] -.56-5.26). However, when their primary insurer was Medicare, male never-smokers aged 65-75 compared with 76-85 underwent significantly more repairs over 4.5 years (+3.69 percentage points; 95% CI.16-7.22; representing a 10.4% relative increase from baseline in the proportion of male never-smokers on Medicare undergoing AAA repair). Comparing female smokers (n=2,312) aged 65-75 (54%) vs. 76-85 (46%), there was no significant change in repairs over 4.5 years (-.66 percentage points; 95% CI -4.57-3.26).

CONCLUSIONS

The USPSTF 2014 AAA guidelines were associated with modestly increased repairs in male never-smokers aged 65-75 only on Medicare. There was no impact among female smokers. Higher-grade recommendations and improved guideline adherence may be requisites for change.

Psychosocial consequences of screening-detected abdominal aortic aneurisms: a cross-sectional study

OBJECTIVE

In Sweden, an abdominal aortic aneurysm (AAA) screening programme was gradually implemented from 2009 to reduce the incidence of rupture and thereby mortality. AAA screening introduces a variety of unintended, but generally unavoidable, harms, e.g. stress and worry. Such psychosocial consequences have previously only been investigated with generic measures. Therefore, the aim of this study was to describe and compare the psychosocial consequences in men with a screening detected AAA to men with a normal screening result after they participated in the Swedish national AAA-screening programme using a validated psychometric instrument.

MATERIAL AND METHODS

This study was a cross-sectional survey. Data were originally collected to validate the COS-AAA and has previously been published in details. The Consequences of Screening in Abdominal Aortic Aneurysm (COS-AAA) questionnaire was sent to 250 men with a screening detected AAA and 500 with a normal screening result who were randomly selected from a Swedish population-based screening register.

RESULTS

In total, 158 (63%) men with a screening detected AAA and 275 (55%) men with a normal screening result completed the COS-AAA. We found that men with a screening detected AAA reported negative psychosocial consequences to a greater extent in 10 of 13 COS-AAA Part 1 scales, all statistically significant except three (behaviour, sleep and negative experiences from examination). For COS-AAA Part 2, there was a statistically significant difference between groups in four of five scales.

CONCLUSIONS

Men diagnosed with a screening detected AAA, reported more negative psychosocial consequences compared to men with a normal result. Screening for abdominal aorta aneurism (AAA) introduces intended benefits and unintended harms. Adequate measures are necessary to determine the balance between them.Key points:This study applied a condition-specific questionnaire with high content validity and adequate psychometric properties to measure psychosocial consequences in men participating in AAA screening.We found that men with a screening detected AAA reported more negative psychosocial consequences than men with a normal aorta size.The risk of negative psychosocial consequences is important to include in the decision making on whether to participate in screening or not.

The Femoral Venoarterial Perfusion During Open Abdominal Aortic Aneurysm Repair in Patient With Renal Transplant

We report of a patient with abdominal aortic aneurysm and renal transplant who underwent aneurysm repair. These patients can be treated by eather open or endovascular approach, depending on several factors, including aneurysm morphologic suitability for endovascular tretament, age of patient, and comorbidities.The main challange with open repair approach is to maintain renal transplant perfusion during the aortic cross clamping. Several methods of renal transplant perfusion during aneurysm repair have been described. In this case, we opted for open aneurysm repair beacuse of the age of the patient. The femoral venoarterial perfusion technique using extracorporal circulation machine was employed. We found this technique safe and easy in treating such patients.

Prospect of positron emission tomography for abdominal aortic aneurysm risk stratification

Abdominal aortic aneurysm (AAA) disease is characterized by an asymptomatic, permanent, focal dilatation of the abdominal aorta progressing towards rupture, which confers significant mortality. Patient management and surgical decisions rely on aortic diameter measurements via abdominal ultrasound surveillance. However, AAA rupture can occur at small diameters or may never occur at large diameters, implying that anatomical size is not necessarily a sufficient indicator. Molecular imaging may help identify high-risk patients through AAA evaluation independent of aneurysm size, and there is the question of the potential role of positron emission tomography (PET) and emerging role of novel radiotracers for AAA. Therefore, this review summarizes PET studies conducted in the last 10 years and discusses the usefulness of PET radiotracers for AAA risk stratification. The most frequently reported radiotracer was [18F]fluorodeoxyglucose, indicating inflammatory activity and reflecting the biomechanical properties of AAA. Emerging radiotracers include [18F]-labeled sodium fluoride, a calcification marker, [64Cu]DOTA-ECL1i, an indicator of chemokine receptor type 2 expression, and [18F]fluorothymidine, a marker of cell proliferation. For novel radiotracers, preliminary trials in patients are warranted before their widespread clinical implementation. AAA rupture risk is challenging to evaluate; therefore, clinicians may benefit from PET-based risk assessment to guide patient management and surgical decisions.

Suppression of Vascular Macrophage Activation by Nitro-Oleic Acid and its Implication for Abdominal Aortic Aneurysm Therapy

PURPOSE

Abdominal aortic aneurysm (AAA) is one of the leading causes of death in the developed world and is currently undertreated due to the complicated nature of the disease. Herein, we aimed to address the therapeutic potential of a novel class of pleiotropic mediators, specifically a new drug candidate, nitro-oleic acid (NO2-OA), on AAA, in a well-characterized murine AAA model.

METHODS

We generated AAA using a mouse model combining AAV.PCSK9-D377Y induced hypercholesterolemia with angiotensin II given by chronic infusion. Vehicle control (PEG-400), oleic acid (OA), or NO2-OA were subcutaneously delivered to mice using an osmotic minipump. We characterized the effects of NO2-OA on pathophysiological responses and dissected the underlying molecular mechanisms through various in vitro and ex vivo strategies.

RESULTS

Subcutaneous administration of NO2-OA significantly decreased the AAA incidence (8/28 mice) and supra-renal aorta diameters compared to mice infused with either PEG-400 (13/19, p = 0.0117) or OA (16/23, p = 0.0078). In parallel, the infusion of NO2-OA in the AAA model drastically decreased extracellular matrix degradation, inflammatory cytokine levels, and leucocyte/macrophage infiltration in the vasculature. Administration of NO2-OA reduced inflammation, cytokine secretion, and cell migration triggered by various biological stimuli in primary and macrophage cell lines partially through activation of the peroxisome proliferator-activated receptor-gamma (PPARγ). Moreover, the protective effect of NO2-OA relies on the inhibition of macrophage prostaglandin E2 (PGE2)-induced PGE2 receptor 4 (EP4) cAMP signaling, known to participate in the development of AAA.

CONCLUSION

Administration of NO2-OA protects against AAA formation and multifactorial macrophage activation. With NO2-OA currently undergoing FDA approved phase II clinical trials, these findings may expedite the use of this nitro-fatty acid for AAA therapy.

Screening for Abdominal Aortic Aneurysms and Risk Factors in 65-Year-Old Men in Oslo, Norway

Purpose

To investigate the prevalence of and risk factors for abdominal aortic aneurysm (AAA) in 65-year-old men in Oslo, Norway.

Materials and Methods

From May 2011, until September 2019, the annual population of 65-year-old men living in Oslo were invited to an ultrasonographic screening of the abdominal aorta. Candidates received a one-time invitation by mail, including a questionnaire on possible risk factors and comorbidities. Abdominal aortic outer-to-outer diameter and ankle-brachial index were measured by the screening team. Participants were allocated into three groups: non-, sub- and aneurysmal aorta. Written information on recommended follow-up regime was given to participants with an aortic diameter ≥25 mm. Univariate and multivariate analyses of potential risk factors were performed, in addition to descriptive analyses and significance testing.

Results

In total, 19,328 were invited, 13,215 men were screened, of which 12,822 accepted inclusion in the study. Aortic diameter was registered for 12,810 participants and 330 men had aortic diameter ≥30 mm, giving a prevalence of AAA of 2.6% (95% confidence interval (CI) 2.31-2.86). We identified 4 independent risk factors for AAA: smoking (OR = 3.64, 95% CI 2.90-4.58), hypertension (OR = 1.87, 95% CI 1.49-2.35), BMI >30 (OR = 1.02, 95% CI 1.00-1.03), and diabetes mellitus (OR = 0.52, 95% CI 0.35-0.79), the latter showing an inverse association with AAA growth. A subgroup of 862 men with aortic diameters 25-29 mm had a significantly higher prevalence of BMI >25, smoking and family history of AAA, compared to participants with aortic diameter <25 mm.

Conclusion

Among the participants in this study, the prevalence of abdominal aortic aneurysms was 2.6%. Participants with AAA more frequently reported cardiovascular risk factors, and less frequently diabetes mellitus.

Screening for abdominal aortic aneurysms in Canada: 2020 review and position statement of the Canadian Society for Vascular Surgery

Abdominal aortic aneurysms (AAAs) remain a major risk to patients, despite level 1 evidence for screening to prevent rupture events and decrease mortality. In 2007, the Canadian Society for Vascular Surgery (CSVS) published a review and position statement for AAA screening in Canada. Since that publication, there have been a number of updates in the published literature affecting screening recommendations. In this paper, we present a review of some of the controversies in the AAA screening literature to help elucidate differences in the various published screening guidelines. This article represents a review of the data and updated recommendations for AAA screening in the Canadian population on behalf of the CSVS.

Les anévrismes de l’aorte abdominale (AAA) continuent de poser un risque majeur pour les patients, malgré des données probantes de niveau 1 à l’appui du dépistage pour prévenir les ruptures et réduire la mortalité. En 2007, la Société canadienne de chirurgie vasculaire (SCCV) a publié une revue et un énoncé de position sur le dépistage de l’AAA au Canada. Depuis lors, plusieurs mises à jour ont paru dans la littérature et elles ont un impact sur les recommandations relatives au dépistage. Dans le présent article, nous présentons une synthèse de quelques controverses soulevées dans la littérature sur le dépistage de l’AAA afin d’expliquer les différences entre les diverses lignes directrices publiées à ce sujet. Cet article propose au nom de la SCCV une revue des données probantes et des recommandations à jour sur le dépistage de l’AAA dans la population canadienne.

Association of Ankle Brachial Index with Clinical Outcomes Following Percutaneous Coronary Intervention in Patients with Aortic Aneurysm

Objective Since patients with thoracic aortic aneurysm (TAA)/abdominal aortic aneurysm (AAA) are often complicated with coronary artery disease, it is common for those patients to undergo percutaneous coronary intervention (PCI). The ankle brachial index (ABI) is usually measured in patients with TAA/AAA to screen the presence of peripheral arterial disease. The present study investigated the association between the ABI and clinical outcomes following PCI in patients with TAA/AAA. Methods We divided 200 TAA/AAA patients who underwent PCI into a normal ABI group (n=137) and an abnormal ABI group (n=63) according to the ABI cut-off level of 1.00. The primary endpoint was one-year major adverse cardiovascular events (MACE), defined as the composite of cardiovascular death, non-fetal myocardial infarction, stroke, target vessel revascularization, and hospitalization for heart failure. Results Mean ABIs in the normal and abnormal ABI groups were 1.12±0.09 and 0.86±0.11, respectively (p<0.01). Kaplan-Meier curves showed MACE were more frequent in the abnormal ABI group than in the normal ABI group (p=0.01). A multivariate Cox hazard analysis revealed that an abnormal ABI was significantly associated with 1-year MACE (vs. ABI ≥1.0: HR 3.02, 95% confidence interval 1.00-9.08, p=0.049). Conclusion Among patients with TAA/AAA who underwent PCI, abnormal ABI was significantly associated with 1-year MACE, suggesting the utility of the ABI measurement in this high-risk population.

Symptomatic and asymptomatic peripheral artery disease and the risk of abdominal aortic aneurysm: The Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND AIMS

Symptomatic peripheral artery disease (PAD) is a risk factor for abdominal aortic aneurysm (AAA). However, data on the association of asymptomatic PAD with AAA are limited. We explored the association of symptomatic and asymptomatic PAD with AAA.

METHODS

We primarily assessed a prospective association of symptomatic (based on clinical history) and asymptomatic (ankle-brachial index ≤0.9) PAD at baseline (1987-89 [ages 45-64 years]) with incident AAA in a biracial community-based cohort, the Atherosclerosis Risk in Communities Study. We secondarily investigated a cross-sectional association of PAD with ultrasound-based AAA (diameter≥3.0 cm) (2011-13 [ages 67-91 years]).

RESULTS

Of 14,148 participants (55.1% female, 25.5% black, 0.9% with symptomatic PAD) in our prospective analysis (median follow-up 22.5 years), 530 (3.7%) developed incident AAA. Symptomatic PAD had a higher hazard ratio (HR) of incident AAA [4.91 (95%CI 2.88-8.37)], as did asymptomatic PAD with ABI≤0.9 [2.33 (1.55-3.51)], compared to the reference ABI>1.1-1.2 in demographically-adjusted models. Crude 15-year cumulative incidence of AAA in these three groups were 12.3%, 3.9%, and 1.5%, respectively. The associations remained significant after accounting for other potential confounders [corresponding HR 2.96 (95%CI 1.73-5.07) and 1.52 (95%CI 1.00-2.30), respectively]. The cross-sectional analysis demonstrated similar patterns with ultrasound-based AAA [odds ratio 2.46 (95%CI 1.26-4.81) for symptomatic PAD and 3.98 (1.96-8.08) for asymptomatic PAD in a demographically-adjusted model].

CONCLUSIONS

Our prospective and cross-sectional data show elevated risk of AAA in both symptomatic and asymptomatic PAD. Our data support the current recommendation of AAA screening in symptomatic PAD patients and suggest the potential extension to asymptomatic PAD patients as well.

Maresin 1 activates LGR6 signaling to inhibit smooth muscle cell activation and attenuate murine abdominal aortic aneurysm formation

The specialized pro-resolving lipid mediator maresin 1 (MaR1) is involved in the resolution phase of tissue inflammation. It was hypothesized that exogenous administration of MaR1 would attenuate abdominal aortic aneurysm (AAA) growth in a cytokine-dependent manner via LGR6 receptor signaling and macrophage-dependent efferocytosis of smooth muscle cells (SMCs). AAAs were induced in C57BL/6 wild-type (WT) mice and smooth muscle cell specific TGF-β2 receptor knockout (SMC-TGFβr2^-/- ) mice using a topical elastase AAA model. MaR1 treatment significantly attenuated AAA growth as well as increased aortic SMC α-actin and TGF-β2 expressions in WT mice, but not SMC-TGFβr2^-/- mice, compared to vehicle-treated mice. In vivo inhibition of LGR6 receptors obliterated MaR1-dependent protection in AAA formation and SMC α-actin expression. Furthermore, MaR1 upregulated macrophage-dependent efferocytosis of apoptotic SMCs in murine aortic tissue during AAA formation. In vitro studies demonstrate that MaR1-LGR6 interaction upregulates TGF-β2 expression and decreases MMP2 activity during crosstalk of macrophage-apoptotic SMCs. In summary, these results demonstrate that MaR1 activates LGR6 receptors to upregulate macrophage-dependent efferocytosis, increases TGF-β expression, preserves aortic wall remodeling and attenuate AAA formation. Therefore, this study demonstrates the potential of MaR1-LGR6-mediated mitigation of vascular remodeling through increased efferocytosis of apoptotic SMCs via TGF-β2 to attenuate AAA formation.

Long Term Outcome of Screen Detected Sub-Aneurysmal Aortas in 65 Year Old Men: a Single Scan After Five Years Identifies Those at Risk of Needing AAA Repair

OBJECTIVE

The epidemiology of sub-aneurysmal aortic dilatation (SAA) 25 - 29 mm is not fully understood, and the management of SAA is debated. Lack of evidence is particularly problematic in the screening setting. This study aimed to evaluate the long term outcome of men with screen detected SAAs, focusing on progression to an abdominal aortic aneurysm (AAA), and on the AAAs reaching the threshold diameter for surgical repair.

METHODS

Between 2006 and 2015, all 65 year old men with a screen detected SAA in middle Sweden were re-examined with ultrasound after five and 10 years. The primary outcomes were expansion to AAA ≥ 30 mm and progression to AAA ≥ 55 mm. Secondary outcomes were risk factors for progression, repair rate, and mortality.

RESULTS

A total of 1 020 65 year old men with a SAA were identified, of whom 940 (92.2%; 95% confidence interval 91.0 - 93.8) had follow up. The Kaplan-Meier estimated incidence of AAA ≥ 30 mm development after the five year follow up (which was de facto carried out after a mean of 4.9 years) was 65.8% (61.6 - 69.4), all < 55 mm. The corresponding KM-estimated incidence after the 10 year follow up (carried out after a mean of 11.9 years) was 95.1% (90.1 - 97.4), and 29.7% (18.0 - 39.7) reached ≥ 55 mm. All 41 SAAs eventually expanding to ≥ 55 mm were ≥ 30 mm at the five year follow up. Of these, 32 had surgical repair with 100% survival, six have scheduled repairs, and three (7.3%) were unfit for repair. The KM estimated all cause mortality rates at five and 10 years were 7.0% and 17.9%, respectively, with no proven AAA related deaths.

CONCLUSION

A majority of SAAs eventually progress to an AAA, of which 30% are estimated to eventually reach the threshold for repair within 10 years. A follow up policy with an ultrasound examination after five years can safely and effectively identify those SAAs at risk of developing into clinically significant AAAs needing repair and may be considered for anyone with reasonably good life expectancy.

Modelling the impact of changes to abdominal aortic aneurysm screening and treatment services in England during the COVID-19 pandemic

Background

The National Health Service (NHS) abdominal aortic aneurysm (AAA) screening programme (NAAASP) in England screens 65-year-old men. The programme monitors those with an aneurysm, and early intervention for large aneurysms reduces ruptures and AAA-related mortality. AAA screening services have been disrupted following COVID-19 but it is not known how this may impact AAA-related mortality, or where efforts should be focussed as services resume.

Methods

We repurposed a previously validated discrete event simulation model to investigate the impact of COVID-19-related service disruption on key outcomes. This model was used to explore the impact of delayed invitation and reduced attendance in men invited to screening. Additionally, we investigated the impact of temporarily suspending scans, increasing the threshold for elective surgery to 7cm and increasing drop-out in the AAA cohort under surveillance, using data from NAAASP to inform the population.

Findings

Delaying invitation to primary screening up to two years had little impact on key outcomes whereas a 10% reduction in attendance could lead to a 2% lifetime increase in AAA-related deaths. In surveillance patients, a 1-year suspension of surveillance or increase in the elective threshold resulted in a 0.4% increase in excess AAA-related deaths (8% in those 5–5.4cm at the start). Longer suspensions or a doubling of drop-out from surveillance would have a pronounced impact on outcomes.

Interpretation

Efforts should be directed towards encouraging men to attend AAA screening service appointments post-COVID-19. Those with AAAs on surveillance should be prioritised as the screening programme resumes, as changes to these services beyond one year are likely to have a larger impact on surgical burden and AAA-related mortality.

Editor's Choice - Infra-Renal Aortic Diameter and Cardiovascular Risk: Making Better Use of Abdominal Aortic Aneurysm Screening Outcomes

OBJECTIVE

Aortic diameter (AD), used traditionally for abdominal aortic aneurysm (AAA) screening may have a role in assessing cardiovascular risk. Unfortunately, AD estimates for those without AAA are underutilised, whilst cardiovascular risk is sub-optimally managed in those with AAA. Our objective was to examine the association between AD measurements and future cardiovascular risk.

METHODS

Retrospective analysis of three databases of male participants screened for aortic aneurysm disease. Imaging and clinical data were obtained from three independent sources: 1) the Multi-centre Aneurysm Screening Study (MASS) trial (n = 26 882 men); 2) the 2013/14 cohort of the English NHS AAA Screening Programme (NAAASP) (n = 237 441 men) linked with NHS hospital admission and death registry data; and 3) the Framingham Heart Study (FHS) offspring cohort (n = 649). Associations between maximal aortic diameter, as measured on ultrasound or computed tomography, and cardiovascular outcomes were examined.

RESULTS

Cardiovascular mortality in the MASS trial, was higher in men with AAA at 13 years of follow up, compared to those without (Hazard Ratio [HR] 2.22, 95% CI 1.97-2.50, p < .001). Contemporary risk of major adverse cardiovascular events in the NAAASP was highest in those with an AAA (HR 2.91, 95% CI 2.00-4.25), whilst, extremes of aortic diameter were associated with increased risk for cardiovascular events. Aortic diameter was an independent risk factor for cardiovascular events in the FHS dataset.

CONCLUSION

Irrespective of the diagnosis of AAA, men attending for AAA screening who are found to have an abnormal aortic diameter are at high risk of future cardiovascular events. This currently unutilised data from AAA screening programmes has the potential to improve preventative management of cardiovascular risk.

Three-dimensional ultrasound improves identification of patients with abdominal aortic aneurysms reaching the threshold for repair

OBJECTIVE

Conventional two-dimensional ultrasound (2D-US) has been the recommended and preferred modality for the diagnosis and surveillance of abdominal aortic aneurysms (AAAs). Measurement of the aneurysm diameter using three-dimensional ultrasound (3D-US) has shown promising results in a research setting, improving agreement and reproducibility. However, studies evaluating 3D-US in a clinical context are lacking, which could hinder the optimal usage of this new modality. In the present study, we investigated the clinical value of 3D-US for AAA surveillance compared with the current standard 2D-US examination.

METHODS

Data from 126 patients with infrarenal AAAs <50 mm and 55 mm (female and male, respectively) were available for analysis. Eligibility was determined using the standard 2D-US anteroposterior (AP) diameter with a dual-plane technique. All the patients had subsequently undergone additional 3D-US and computed tomography angiography (CTA). Using CTA as the reference standard, the maximal standard 2D-US AP diameter was compared with that from 3D-US.

RESULTS

All 126 AAAs were, per the inclusion criteria, small, with no intervention indicated. With the addition of 3D-US imaging to the 2D-US-based surveillance program, the AAA diameter threshold (50 and 55 mm) was exceeded for 31 of the 126 patients (25%). These 31 patients were withdrawn from the present study and referred for treatment planning. Compared with the CTA AP diameter (mean, 49 ± 7.2 mm), the mean 3D-US AP diameter (mean, 49 ± 6.7 mm) was significantly more accurate than the standard mean 2D-US AP diameter (45 ± 6.2 mm; kappa value, 0.86 ± 0.05; 95% confidence interval, 0.76-0.96; kappa value, 0.01 ± 0.04; 95% confidence interval, -0.05 to 0.09, respectively).

CONCLUSIONS

For clinical use, the AAA diameter assessment using 3D-US was significantly more accurate than that with 2D-US and can substantially change the clinical management, from surveillance to operative treatment, for approximately one fourth of patients with an AAA. Further studies evaluating the clinical consequences of the 2D to 3D paradigm shift in AAA diagnostics are warranted, including sensitivity, specificity, agreement, and reproducibility estimation.

Machine learning approaches to surrogate multifidelity Growth and Remodeling models for efficient abdominal aortic aneurysmal applications

Computational Growth and Remodeling (G&R) models have been widely used to capture the pathological development of arterial diseases and have shown promise for aiding clinical diagnosis, prognosis prediction, and staging classification. However, due to the high complexity of the arterial adaptation mechanism, high-fidelity arterial G&R simulation usually takes hours or even days, which hinders its application in clinical practice. To remedy this problem, we develop a computationally efficient arterial G&R simulation framework that comprehensively combines the physics-based G&R simulations and data-driven machine learning approaches. The proposed framework greatly enhances the computational efficiency of arterial G&R simulations, thereby enabling more time-consuming arterial applications, including personalized parameter estimation and arterial disease progression prediction. In particular, we achieve significant computational cost reduction mainly through two methods: (1) constructing a Multifidelity Surrogate (MFS) to approximate multifidelity G&R simulations by using a cokriging approach and (2) developing a novel iterative optimization algorithm for personalized parameter estimation. The proposed framework is demonstrated by estimating G&R model parameters and predicting individual aneurysm growth using follow-up CT images of Abdominal Aortic Aneurysms (AAAs) from 21 patients. Results show that the personalized parameters are satisfactorily estimated and the growth of AAAs is predicted within the clinically relevant time frame, i.e., less than 2 h, without a loss of accuracy.

Evaluating the Cost-Effectiveness of Changes to the Surveillance Intervals in the UK Abdominal Aortic Aneurysm Screening Programme

OBJECTIVES

To investigate the safety and cost-effectiveness of lengthening the time between surveillance ultrasound scans in the UK Abdominal Aortic Aneurysm (AAA) Screening Programme.

METHODS

A discrete event simulation model was used to evaluate the cost-effectiveness of AAA screening for men aged 65, comparing current surveillance intervals to 6 alternative surveillance interval strategies that lengthened the time between surveillance scans for 1 or more AAA size categories. The model considered clinical events and costs incurred over a 30-year time horizon and the cost per quality-adjusted life year (QALY). The model adopted the National Health Service perspective and discounted future costs and benefits at 3.5%.

RESULTS

Compared with current practice, alternative surveillance strategies resulted in up to a 4% reduction in the number of elective AAA repairs but with an increase of up to 1.6% in the number of AAA ruptures and AAA-related deaths. Alternative strategies resulted in a small reduction in QALYs compared to current practice but with reduced costs. Two strategies that lengthened surveillance intervals in only very small AAAs (3.0-3.9 cm) provided, at a cost-effectiveness threshold of £20 000 per QALY, the highest positive incremental net benefit. There was negligible chance that current practice is the most cost-effective strategy at any threshold below £40 000 per QALY.

CONCLUSIONS

Lengthening surveillance intervals in the UK Abdominal Aortic Aneurysm Screening Programme, especially for small AAA, can marginally reduce the incremental cost per QALY of the program. Nevertheless, whether the cost savings from refining surveillance strategies justifies a change in clinical practice is unclear.

Validation of natural language processing to determine the presence and size of abdominal aortic aneurysms in a large integrated health system

OBJECTIVE

Previous studies of the natural history of abdominal aortic aneurysms (AAAs) have been limited by small cohort sizes or heterogeneous analyses of pooled data. By quickly and efficiently extracting imaging data from the health records, natural language processing (NLP) has the potential to substantially improve how we study and care for patients with AAAs. The aim of the present study was to test the ability of an NLP tool to accurately identify the presence or absence of AAAs and detect the maximal abdominal aortic diameter in a large dataset of imaging study reports.

METHODS

Relevant imaging study reports (n = 230,660) from 2003 to 2017 were obtained for 32,778 patients followed up in a prospective aneurysm surveillance registry within a large, diverse, integrated healthcare system. A commercially available NLP algorithm was used to assess the presence of AAAs, confirm the absence of AAAs, and extract the maximal diameter of the abdominal aorta, if stated. A blinded expert manual review of 18,000 randomly selected imaging reports was used as the reference standard. The positive predictive value (PPV or precision), sensitivity (recall), and the kappa statistics were calculated.

RESULTS

Of the randomly selected 18,000 studies that underwent expert manual review, 48.7% were positive for AAAs. In confirming the presence of an AAA, the interrater reliability of the NLP compared with the expert review showed a kappa value of 0.84 (95% confidence interval [CI], 0.83-0.85), with a PPV of 95% and sensitivity of 88.5%. The NLP algorithm showed similar results for confirming the absence of an AAA, with a kappa of 0.79 (95% CI, 0.799-0.80), PPV of 77.7%, and sensitivity of 91.9%. The kappa, PPV, and sensitivity of the NLP for correctly identifying the maximal aortic diameter was 0.88 (95% CI, 0.87-0.89), 88.8%, and 88.2% respectively.

CONCLUSIONS

The use of NLP software can accurately analyze large volumes of radiology report data to detect AAA disease and assemble a contemporary aortic diameter-based cohort of patients for longitudinal analysis to guide surveillance, medical management, and operative decision making. It can also potentially be used to identify from the electronic medical records pre- and postoperative AAA patients "lost to follow-up," leverage human resources engaged in the ongoing surveillance of patients with AAAs, and facilitate the construction and implementation of AAA screening programs.

Feasibility and Efficiency Study of a Population-Based Abdominal Aortic Aneurysm Screening Program in Men and Women in Spain

BACKGROUND

Based on current evidence, one-time screening for abdominal aortic aneurysm (AAA) in men using ultrasound evaluation reduces mortality related to AAA rupture and is considered cost-effective, although all-cause mortality reduction still remains in question. In Spain, there is no population screening program for AAA, so the aim of our study was to perform a pilot population screening program in our area to assess feasibility and efficiency of an AAA screening program for men and women.

METHODS

A population AAA screening pilot program was performed in a Barcelona area, including 400,000 inhabitants. According to inclusion criteria, 4,730 individuals aged 65 years at the moment of the trial were invited for screening (2,089 men and 2,641 women). Primary care doctors, trained in duplex ultrasound abdominal evaluations, performed an abdominal aortic measurement. Individuals with a previous diagnosis of AAA, limited life expectancy, or wrong contact data were excluded. Participation data, aortic diameters, AAA prevalence, and related cardiovascular risk factors were analyzed. The results were used in a cost-utility model to assess the efficiency of the screening program.

RESULTS

Participation was 50.3% in men and 44% in women. Eleven patients were excluded because of previously diagnosed AAA. Five new asymptomatic AAA were detected in 65-year-old men (0.5% prevalence), all being active smokers. When considering patients excluded for previous AAA diagnosis, the prevalence in 65-year-old men reached 1.4%. Global AAA prevalence in smoking men reached 2.67%. No AAA was detected in women. Subaneurysmal aorta prevalence in men was 2.9% (n = 29), and in women, it was 0.08% (n = 2). A cost-utility analysis model on screening versus no screening retrieved 13,664€ per quality-adjusted life years at a 10-year horizon and 39,455€ per quality-adjusted life years at a 30-year horizon.

CONCLUSIONS

AAA population-based screening by ultrasound evaluation in primary care is logistically feasible in our area. Despite that, AAA prevalence is lower than expected in men, and null in women. Cost-utility model results indicate that a local AAA screening program is only efficient in a 30 years' time horizon. Such inefficient results for a population screening make it necessary to consider other strategies such as opportunistic or subgroup screening in our area.

Screening for abdominal aortic aneurysm in patients with clinically manifest vascular disease

AIMS

Declining prevalence of abdominal aortic aneurysm (AAA) might force a more targeted screening approach (high-risk populations only) in order to maintain (cost-)effectiveness. We aimed to determine temporal changes in the prevalence of screening-detected AAA, to assess AAA-related surgery, and evaluate all-cause mortality in patients with manifest vascular disease.

METHODS AND RESULTS

We included patients with manifest vascular disease but without a history of AAA enrolled in the ongoing single-centre prospective UCC-SMART cohort study. Patients were screened at baseline for AAA by abdominal ultrasonography. We calculated sex- and age-specific prevalence of AAA, probability of survival in relation to the presence of AAA, and the proportion of patients undergoing AAA-related surgery. Prevalence of screening-detected AAA in 5440 screened men was 2.5% [95% confidence interval (CI) 2.1-2.9%] and in 1983 screened women 0.7% (95% CI 0.4-1.1%). Prevalence declined from 1997 until 2017 in men aged 70-79 years from 8.1% to 3.2% and in men aged 60-69 years from 5.7% to 1.0%. 36% of patients with screening-detected AAA received elective AAA-related surgery during follow-up (median time until surgery = 5.3 years, interquartile range 2.5-9.1). Patients with screening-detected AAA had a lower probability of survival (sex and age adjusted) compared to patients without screening-detected AAA (51%, 95% CI 41-64% vs. 69%, 95% CI 68-71%) after 15 years of follow-up.

CONCLUSION

The prevalence of screening-detected AAA has declined over the period 1997-2017 in men with vascular disease but exceeds prevalence in already established screening programs targeting 65-year-old men. Screening for AAA in patients with vascular disease may be cost-effective, but this remains to be determined.

Abdominal aortic aneurysms part one: Epidemiology, presentation and preoperative considerations

An abdominal aortic aneurysm is an irreversible dilatation of the abdominal aorta. The majority of abdominal aortic aneurysms are asymptomatic and identified incidentally while investigating a separate pathology. Others are detected by national screening programmes and some present due to a growth or rupture. Symptomatic or ruptured aneurysms require urgent or emergency repair in patients fit for surgery. Perioperative practitioners should therefore be aware of how patients with abdominal aortic aneurysms present and are investigated, so that they can implement timely management. Guidelines have been recently updated to reflect this. This literature review discusses these recommendations and explores the evidence upon which they are based. The aim of this article is to highlight the important preoperative principles that need to be considered in cases of abdominal aortic aneurysm.

Misdiagnosis of ruptured abdominal aortic aneurysms is common and is associated with increased mortality

OBJECTIVE

To investigate the rate of misdiagnosis in the emergency department in patients with ruptured abdominal aortic aneurysms (rAAAs), and to investigate how misdiagnosis affects rAAA mortality.

METHODS

Data were extracted from the Swedish Cause of Death Registry and the Swedish National Registry for Vascular Surgery from 2010 to 2015. All rAAA patients registered in the health care system in the west of Sweden were identified. Medical charts for rAAA patients were reviewed, and patients who were correctly diagnosed at the first assessment in the emergency department were compared with patients who were misdiagnosed.

RESULTS

Altogether, 455 patients with rAAA were identified, including both patients who underwent surgery and those who did not. One hundred seventy-seven (38.9%) were initially misdiagnosed. The mortality rate was 74.6% in patients who were misdiagnosed, as compared with 62.9% in correctly diagnosed patients (P = .01). The adjusted odds ratio for mortality in misdiagnosed patients relative to correctly diagnosed patients was 1.83 (95% confidence interval, 1.13-2.96) (P = .01). When excluding patients offered palliative care (n = 134) after detection of the rAAA, the mortality in initially misdiagnosed patients was 65.1% as compared with 46.4% in correctly diagnosed patients (P = .001). In patients reaching surgical intervention, 37 (45.1%) of the primarily misdiagnosed patients died (30-day or in-hospital mortality) as compared with 63 (38.0%) of the correctly diagnosed (P = .34).

CONCLUSIONS

Misdiagnosis is common in patients with rAAA, and it is associated with a substantially higher risk of dying from the ruptured aneurysm.