Screening women aged 65 years or over for abdominal aortic aneurysm: a modelling study and health economic evaluation

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.

Health Economic Research Assessing the Value of Early Detection of Cardiovascular Disease: A Systematic Review

INTRODUCTION

Cardiovascular disease (CVD) is the most prominent cause of death worldwide and has a major impact on healthcare budgets. While early detection strategies may reduce the overall CVD burden through earlier treatment, it is unclear which strategies are (most) efficient.

AIM

This systematic review reports on the cost effectiveness of recent early detection strategies for CVD in adult populations at risk.

METHODS

PubMed and Scopus were searched to identify scientific articles published between January 2016 and May 2022. The first reviewer screened all articles, a second reviewer independently assessed a random 10% sample of the articles for validation. Discrepancies were solved through discussion, involving a third reviewer if necessary. All costs were converted to 2021 euros. Reporting quality of all studies was assessed using the CHEERS 2022 checklist.

RESULTS

In total, 49 out of 5552 articles were included for data extraction and assessment of reporting quality, reporting on 48 unique early detection strategies. Early detection of atrial fibrillation in asymptomatic patients was most frequently studied (n = 15) followed by abdominal aortic aneurysm (n = 8), hypertension (n = 7) and predicted 10-year CVD risk (n = 5). Overall, 43 strategies (87.8%) were reported as cost effective and 11 (22.5%) CVD-related strategies reported cost reductions. Reporting quality ranged between 25 and 86%.

CONCLUSIONS

Current evidence suggests that early CVD detection strategies are predominantly cost effective and may reduce CVD-related costs compared with no early detection. However, the lack of standardisation complicates the comparison of cost-effectiveness outcomes between studies. Real-world cost effectiveness of early CVD detection strategies will depend on the target country and local context.

REGISTRATION OF SYSTEMATIC REVIEW

CRD42022321585 in International Prospective Registry of Ongoing Systematic Reviews (PROSPERO) submitted at 10 May 2022.

HMGB1/TLR4 signaling pathway enhances abdominal aortic aneurysm progression in mice by upregulating necroptosis

OBJECTIVE AND DESIGN

The age-associated increases in aseptic inflammation and necroptosis are closely related to the emergence of various age-associated diseases.

METHODS

In this study, the role of HMGB1/TLR4-induced necroptosis in abdominal aortic aneurysm (AAA) formation was investigated. First, the levels of sterile inflammatory mediators (HMGB1, TLR4) and necroptosis markers were measured in the abdominal aortas of young and old C57BL/6JNifdc mice. We observed that sterile inflammatory mediators and necroptosis markers were greatly increased in the abdominal aortas of old mice. Then, angiotensin II (Ang II)-induced AAA model in APOE^-/- mice was used in this study. Mice AAA models were treated with the RIP1 inhibitor necrostatin-1 (Nec-1) or the TLR4 inhibitor TAK-242, respectively.

RESULTS

We found that HMGB1, TLR4, and necroptosis markers were elevated in old mice compared with those in young mice. Same elevation was also found in the development of AAA in APOE^-/- mice. In addition, the necroptosis inhibitor Nec-1 alleviated Ang II-induced AAA development while downregulating the expression of HMGB1/TLR4. After blocking TLR4 with TAK-242, the expression of necroptosis markers decreased significantly, and the progression of AAA was also alleviated in APOE^-/- mice.

CONCLUSIONS

Our results indicated that HMGB1/TLR4-mediated necroptosis enhances AAA development in the Ang II-induced AAA model in APOE^-/- mice and that TLR4 might be a potential therapeutic target for AAA management.

Evaluating feasibility of using national registries for identification, invitation, and ultrasound examination of persons with hereditary risk for aneurysm disease-detecting abdominal aortic aneurysms in first degree relatives (adult offspring) to AAA patients (DAAAD)

BACKGROUND

Sweden and the UK invite all 65-year-old men to a population-based ultrasound-based screening program to detect abdominal aortic aneurysms (AAA). First-degree relatives of patients with AAA are reported to have an increased risk to develop AAA, both women and men, but are not invited to screening. The "Detecting AAA in First Degree Relatives to AAA patients" (DAAAD) was designed to detect the true prevalence in adult offspring to AAA patients and to evaluate if national registries could be used for identification of index persons and their adult children with a high risk for the disease. The aim of this study is to summarize the design and methodology for this registry-based study.

METHODS

The study is based on a registry-based extraction and identification of a risk group in the population with a subsequent identification of their adult offspring. The targeted risk group suffers a heredity for a potentially lethal disease, AAA (n = 750) and matched control group without heredity for AAA is also identified and invited (n = 750). The participation rate in the population-based AAA screening program for men is 75% regionally. This population is younger and have a lower prevalence. A participation rate of 65% is considered clinically adequate. For the DAAAD study, a stratified analysis of the primary outcome, prevalence, will be performed for women and men separately. Two other planned projects are based on the material: firstly, evaluation of the anxiety for disease and health-related quality of life (HRQoL) and, secondly, the cost-effectiveness of the study.

DISCUSSION

In conclusion, this feasibility study will be instrumental in supporting the development of a possible new model to invite persons with high risk to develop hereditary rare diseases. To our knowledge, this is a unique, safe, and most likely to be a cost-efficient model to invite targeted risk groups for selected screening. If the study design and the results are shown to be cost-effective at the detected participation rate and prevalence, it should be further evaluated and adopted to a national screening program. The model also invites both women and men, which is unique for this specific patient group, considering that all population-based screening programs only include men.

TRIAL REGISTRATION

This trial is registered at the website of Clinical Trials.

CLINICALTRIALS

gov identifier, NCT4623268.

Association between neighborhood deprivation and presenting with a ruptured abdominal aortic aneurysm before screening age

OBJECTIVE

Recent data indicate social determinants of health (SDOH) have a great impact on prevention and treatment outcomes across a broad variety of disease states, especially cardiovascular diseases. The area deprivation index (ADI) is a validated measure of neighborhood level disadvantage capturing key social determinate factors. Abdominal aortic aneurysm rupture (rAAA) is highly morbid, but also preventable through evidence-based screening. However, the association between rAAA and SDOH is poorly characterized. Our objective is to study the association of SDOH with rAAA and screening age.

METHODS

This retrospective study included patients who underwent operative repair of a rAAA at a multihospital healthcare system (2003-2019). Deprivation was measured by the ADI (scale 1-100), grouped into quintiles for simplicity, with higher quintiles indicating greater deprivation. Patients with the highest quintile ADI (89-100) were categorized as the most deprived. We investigated the association between neighborhood deprivation with the odds of (i) undergoing repair for rAAA before screening age 65 and (ii) undergoing endovascular aortic repair (EVAR) using logistic regression, sequentially modeling nonmodifiable then both nonmodifiable and modifiable confounding variables.

RESULTS

There were 632 patients who met the inclusion criteria (aged 74.2 ± 9.4 years; 174 women [27.6%]; 564 White [89.2%]; ADI 66.8 ± 22.3). Those from the most deprived neighborhoods (n = 118) were younger (71.7 ± 10.0 years vs 74.8 ± 9.2 years; P = .002), more likely to be female (36% vs 26%; P = .031), more likely to be Black (5.9% vs 0.4%; P = .007), and fewer underwent EVAR (28% vs 39.5%; P = .020) compared with those from other neighborhoods. On sequential modeling, residing in the most deprived neighborhoods was associated with undergoing rAAA repair before age 65 after adjusting for nonmodifiable factors (odds ratio [OR], 2.02; 95% confidence interval [CI], 1.39-2.95; P < .001), and nonmodifiable as well as modifiable factors (OR, 2.22; 95% CI, 1.56-3.16; P < .001). Those in the most deprived neighborhoods had a lower odds of undergoing EVAR compared with open repair after adjusting for nonmodifiable factors (OR, 0.64; 95% CI, 0.41-0.98; P = .042), and nonmodifiable as well as modifiable factors (OR, 0.61; 95% CI, 0.37-0.99; P = .047).

CONCLUSIONS

Among patients who underwent rAAA, residing in the most deprived neighborhoods was associated with greater adjusted odds of presenting under age 65 and undergoing an open repair. These neighborhoods represent tangible geographic targets that may benefit from a younger screening age, enhanced education, and access to care. These findings stress the importance of developing strategies for early prevention and diagnosis of cardiovascular diseases among patients with disadvantageous SDOH.

Guidelines on the management of abdominal aortic aneurysms: updates from the Italian Society of Vascular and Endovascular Surgery (SICVE)

The objective of these Guidelines was to revise and update the previous 2016 Italian Guidelines on Abdominal Aortic Aneurysm Disease, in accordance with the National Guidelines System (SNLG), to guide every practitioner toward the most correct management pathway for this pathology. The methodology applied in this update was the GRADE-SIGN version methodology, following the instructions of the AGREE quality of reporting checklist as well. The first methodological step was the formulation of clinical questions structured according to the PICO (Population, Intervention, Comparison, Outcome) model according to which the Recommendations were issued. Then, systematic reviews of the Literature were carried out for each PICO question or for homogeneous groups of questions, followed by the selection of the articles and the assessment of the methodological quality for each of them using qualitative checklists. Finally, a Considered Judgment form was filled in for each clinical question, in which the features of the evidence as a whole are assessed to establish the transition from the level of evidence to the direction and strength of the recommendations. These guidelines outline the correct management of patients with abdominal aortic aneurysm in terms of screening and surveillance. Medical management and indication for surgery are discussed, as well as preoperative assessment regarding patients' background and surgical risk evaluation. Once the indication for surgery has been established, the options for traditional open and endovascular surgery are described and compared, focusing specifically on patients with ruptured abdominal aortic aneurysms as well. Finally, indications for early and late postoperative follow-up are explained. The most recent evidence in the Literature has been able to confirm and possibly modify the previous recommendations updating them, likewise to propose new recommendations on prospectively relevant topics.

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.

Endovascular Abdominal Aortic Aneurysm Repair with Ovation Alto stent graft: Protocol of the ALTAIR study (ALTo endogrAft Italian Registry). (Preprint)

Background

Since 2010, the Ovation Abdominal Stent Graft System has offered an innovative sealing option for abdominal aortic aneurysm (AAA) by including a sealing ring filled with polymer 13 mm from the renal arteries. In August 2020, the redesigned Ovation Alto, with a sealing ring 6 mm closer to the top of the fabric, received CE Mark approval.

Objective

This registry study aims to evaluate intraoperative, perioperative, and postoperative results in patients treated by the Alto stent graft (Endologix Inc.) for elective AAA repair in a multicentric consecutive experience.

Methods

All consecutive eligible patients submitted to endovascular aneurysm repair (EVAR) by Alto Endovascular AAA implantation will be included in this analysis. Patients will be submitted to EVAR procedures based on their own preferences, anatomical features, and operators experience. An estimated number of 300 patients submitted to EVAR with Alto stent graft should be enrolled. It is estimated that the inclusion period will be 24 months. The follow-up period is set to be 5 years. Full data sets and cross-sectional images of contrast-enhanced computed tomography scan performed before EVAR, at the first postoperative month, at 24 or 36 months, and at 5-year follow-up interval will be reported in the central database for a centralized core laboratory review of morphological changes. The primary endpoint of the study is to evaluate the technical and clinical success of EVAR with the Alto stent graft in short- (90-day), mid- (1-year), and long-term (5-year) follow-up periods. The following secondary endpoints will be also addressed: operative time; intraoperative radiation exposure; contrast medium usage; AAA sac shrinkage at 12-month and 5-year follow-up; any potential role of patients’ baseline characteristics, valuated on preoperative computed tomography angiographic study, and of device configuration (number of component) in the primary endpoint.

Results

The study is currently in the recruitment phase and the final patient is expected to be treated by the end of 2023 and then followed up for 5 years. A total of 300 patients will be recruited. Analyses will focus on primary and secondary endpoints. Updated results will be shared at 1- and 3-5-year follow-ups.

Conclusions

The results from this registry study could validate the safety and effectiveness of the new design of the Ovation Alto Stent Graft. The technical modifications to the endograft could allow for accommodation of a more comprehensive range of anatomies on-label.

Trial Registration

ClinicalTrials.gov NCT05234892; https://clinicaltrials.gov/ct2/show/NCT05234892

International Registered Report Identifier (IRRID)

PRR1-10.2196/36995

Ultrasound screening for abdominal aortic aneurysm in high-risk women

Background

Population-wide ultrasound screening programmes for abdominal aortic aneurysm (AAA) for men have already been established in some countries. Women account for one third of aneurysm-related mortality and are four times more likely to experience an AAA rupture than men. Whole-population screening for AAA in women is unlikely to be clinically or economically effective. The aim of this study was to determine the outcomes of a targeted AAA screening programme for women at high risk of AAA.

Method

Women aged 65–74 years deemed at high risk of having an AAA (current smokers, ex-smokers, or with a history of coronary artery disease) were invited to attend ultrasound screening (July 2016 to March 2019) for AAA in the Female Aneurysm screening STudy (FAST). Primary outcomes were attendance for screening and prevalence of AAA. Biometric data, medical history, quality of life (QoL) and aortic diameter on ultrasound imaging were recorded prospectively.

Results

Some 6037 women were invited and 5200 attended screening (86.7 per cent). Fifteen AAAs larger than 29 mm were detected (prevalence 0.29 (95 per cent c.i. 0.18 to 0.48) per cent). Current smokers had the highest prevalence (0.83 (95 per cent c.i. 0.34 to 1.89) per cent) but lowest attendance (75.2 per cent). Three AAAs greater than 5.5 cm were identified and referred for consideration of surgical repair; one woman underwent repair. There was a significant reduction in patient-reported QoL scores following screening.

Conclusion

A low prevalence of AAA was detected in high-risk women, with lowest screening uptake in those at highest risk. Screening for AAA in high-risk women may not be beneficial.

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.

The Polymer-Based Technology in the Endovascular Treatment of Abdominal Aortic Aneurysms

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta that progressively grows until it ruptures. Treatment is typically recommended when the diameter is more than 5 cm. The EVAR (Endovascular aneurysm repair) is a minimally invasive procedure that involves the placement of an expandable stent graft within the aorta to treat aortic disease without operating directly on the aorta. For years, stent grafts' essential design was based on metallic stent frames to support the fabric. More recently, a polymer-based technology has been proposed as an alternative method to seal AAA. This review underlines the two platforms that are based on a polymer technology: (1) the polymer-filled endobags, also known as Endovascular Aneurysm Sealing (EVAS) with Nellix stent graft; and (2) the O-ring EVAR polymer-based proximal neck sealing device, also known as an Ovation stent graft. Polymer characteristics for this particular aim, clinical applications, and durability results are hereby summarized and commented critically. The technique of inflating endobags filled with polymer to exclude the aneurysmal sac was not successful due to the lack of an adequate proximal fixation. The platform that used polymer to create a circumferential sealing of the aneurysmal neck has proven safe and effective.

Configuration of vascular services: a multiple methods research programme

Background

Vascular services is changing rapidly, having emerged as a new specialty with its own training and specialised techniques. This has resulted in the need for reconfiguration of services to provide adequate specialist provision and accessible and equitable services.

Objectives

To identify the effects of service configuration on practice, resource use and outcomes. To model potential changes in configuration. To identify and/or develop electronic data collection tools for collecting patient-reported outcome measures and other clinical information. To evaluate patient preferences for aspects of services other than health-related quality of life.

Design

This was a multiple methods study comprising multiple systematic literature reviews; the development of a new outcome measure for users of vascular services (the electronic Personal Assessment Questionnaire – Vascular) based on the reviews, qualitative studies and psychometric evaluation; a trade-off exercise to measure process utilities; Hospital Episode Statistics analysis; and the development of individual disease models and a metamodel of service configuration.

Setting

Specialist vascular inpatient services in England.

Data sources

Modelling and Hospital Episode Statistics analysis for all vascular inpatients in England from 2006 to 2018. Qualitative studies and electronic Personal Assessment Questionnaire – Vascular evaluation with vascular patients from the Sheffield area. The trade-off studies were based on a societal sample from across England.

Interventions

The data analysis, preference studies and modelling explored the effect of different potential arrangements for service provision on the resource use, workload and outcomes for all interventions in the three main areas of inpatient vascular treatment: peripheral arterial disease, abdominal aortic aneurysm and carotid artery disease. The electronic Personal Assessment Questionnaire – Vascular was evaluated as a potential tool for clinical data collection and outcome monitoring.

Main outcome measures

Systematic reviews assessed quality and psychometric properties of published outcome measures for vascular disease and the relationship between volume and outcome in vascular services. The electronic Personal Assessment Questionnaire – Vascular development considered face and construct validity, test–retest reliability and responsiveness. Models were validated using case studies from previous reconfigurations and comparisons with Hospital Episode Statistics data. Preference studies resulted in estimates of process utilities for aneurysm treatment and for travelling distances to access services.

Results

Systematic reviews provided evidence of an association between increasing volume of activity and improved outcomes for peripheral arterial disease, abdominal aortic aneurysm and carotid artery disease. Reviews of existing patient-reported outcome measures did not identify suitable condition-specific tools for incorporation in the electronic Personal Assessment Questionnaire – Vascular. Reviews of qualitative evidence, primary qualitative studies and a Delphi exercise identified the issues to be incorporated into the electronic Personal Assessment Questionnaire – Vascular, resulting in a questionnaire with one generic and three disease-specific domains. After initial item reduction, the final version has 55 items in eight scales and has acceptable psychometric properties. The preference studies showed strong preference for endovascular abdominal aortic aneurysm treatment (willingness to trade up to 0.135 quality-adjusted life-years) and for local services (up to 0.631 quality-adjusted life-years). A simulation model with a web-based interface was developed, incorporating disease-specific models for abdominal aortic aneurysm, peripheral arterial disease and carotid artery disease. This predicts the effects of specified reconfigurations on workload, resource use, outcomes and cost-effectiveness. Initial exploration suggested that further reconfiguration of services in England to accomplish high-volume centres would result in improved outcomes, within the bounds of cost-effectiveness usually considered acceptable in the NHS.

Limitations

The major source of evidence to populate the models was Hospital Episode Statistics data, which have limitations owing to the complexity of the data, deficiencies in the coding systems and variations in coding practice. The studies were not able to address all of the potential barriers to change where vascular services are not compliant with current NHS recommendations.

Conclusions

There is evidence of potential for improvement in the clinical effectiveness and cost-effectiveness of vascular services through further centralisation of sites where major vascular procedures are undertaken. Preferences for local services are strong, and this may be addressed through more integrated services, with a range of services being provided more locally. The use of a web-based tool for the collection of clinical data and patient-reported outcome measures is feasible and can provide outcome data for clinical use and service evaluation.

Future work

Further evaluation of the economic models in real-world situations where local vascular service reconfiguration is under consideration and of the barriers to change where vascular services do not meet NHS recommendations for service configuration is needed. Further work on the electronic Personal Assessment Questionnaire – Vascular is required to assess its acceptability and usefulness in clinical practice and to develop appropriate report formats for clinical use and service evaluation. Further studies to assess the implications of including non-health-related preferences for care processes, and location of services, in calculations of cost-effectiveness are required.

Study registration

This study is registered as PROSPERO CRD42016042570, CRD42016042573, CRD42016042574, CRD42016042576, CRD42016042575, CRD42014014850, CRD42015023877 and CRD42015024820.

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 9, No. 5. See the NIHR Journals Library website for further project information.

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.

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.