NHS Abdominal Aortic Aneurysm Screening Research Articles

O020 Comparison of indices of deprivation and screening uptake within a local AAA screening programme

Abstract Introduction The NHS Abdominal Aortic Aneurysm Screening Programme (NAAASP) was established nationally to reduce the number of deaths caused by ruptured AAA. NAAASP invites all men in their 65th year for a simple abdominal ultrasound scan. Across the country uptake to the programme varies greatly. The aim of this study is to determine the impact of deprivation on local screening programme attendance. Methods The attendance for patients invited to screening within the Leicester, Leicestershire and Rutland screening NAAASP programme between the years 2016 and 2021 was compared to indices of multiple deprivation (IMD) (derived from their Lower Layer Super Output Area (LSOA) for each patient). Multiple logistic regression was used to determine the most significant component contributing to the IMD score. Results 28,730 men in total were invited to attend. Mean IMD for those that attended screening was 15.6 versus 20.6 for non-attenders (P value <0.001). Multiple regression revealed the IMD domains most associated with non-attendance to screening to be; Health Deprivation and Disability domain (P<0.001), Outdoor living environment domain (P<0.001) and Adult skills and English language proficiency domain (P<0.001). Barriers to housing and service domain including ‘geographical barriers’ which relate to the physical proximity of local services and employment domains did not show any association with attendance. Conclusion In line with the contemporary medical literature, social deprivation affects the uptake of the local National Abdominal Aortic Aneurysm Screening Programme (NAAASP). Health deprivation and disability, Outdoor living environment and adult education domains are most contributory to non-attendance.

Developing and evaluating a prototype public health mobile app on the UK NHS Abdominal Aortic Aneurysm Screening Programme

Abdominal Aortic Aneurysms (AAA) are asymptomatic with advanced age and male sex being risk factors. Due to their significant mortality rate, the NHS AAA Screening programme was introduced in 2012. However, this is not as well-supported compared to other programmes. When it comes to AAA and its screening, health information is also available from different sources potentially leading to confusion. Based on this, our aim was to develop a prototype mobile application on AAA and its screening, centralising all key information, for the general public. Another aim was to assess the app’s usability and impact (i.e. users’ perceptions about screening attendance and knowledge of AAA). 24 participants completed a pre-app questionnaire followed by app testing and a post-app questionnaire. Ethical approval was granted from the Glasgow School of Art. 75% of participants had never heard of AAA and 92% had never heard of its screening. After app use, the participants’ AAA knowledge significantly increased (Z = −4.318, p < 0.001). App use and opinion of screening attendance were also statistically associated (X 1[1, n = 24] = 6.857, p < 0.05). The app’s usability was rated positively in the USE questionnaire. Research is needed on public health apps regarding their impact on screening uptake and public knowledge.

Quality assurance for the NHS abdominal aortic aneurysm screening programme in England.

IntroductionThe National Health Service Abdominal Aortic Aneurysm Screening Programme (NAAASP) was introduced in England in 2009 to offer ultrasound screening to men over 65 years, in order to reduce aneurysm-related deaths. This study describes the development of a quality assurance (QA) process and conducts an analysis of the first round of QA visit reports. The aim was to identify themes where local providers can target their efforts for improvement.MethodsForty-one providers were assessed over 4 years using a process of QA visits adapted from previously established screening programmes. A mixture of qualitative and quantitative methods was used to analyse the 41 QA reports, which identified a range of recommendations for providers. The data were coded for key words and assigned to themes. The number of recommendations per visit report was compared with experience of the providers and performance against national screening standards.ResultsA total of 773 recommendations were made, with an average of 19 per QA visit. Around one third of the recommendations were based on governance and leadership standards, with 43.0 per cent of those based around commissioning and accountability. A significant relationship was seen between number of infrastructure recommendations and performance against standards.ConclusionThis review of a QA cycle found that sound infrastructure is key to the success of a local provider.

Outcomes in Men From the NHS Abdominal Aortic Aneurysm Screening Programme With a Large Aneurysm Referred for Intervention

The NHS Abdominal Aortic Aneurysm Screening Programme (NAAASP) has been implemented since 2013. Men with a large aneurysm >54 mm, either at first screen or during surveillance, are referred for intervention. The aim of the present study was to explore outcomes in these men and to see whether there was any regional variation in treatment rates and type of repair. The study cohort included all men referred to a vascular network with a large abdominal aortic aneurysm (AAA). Basic demographic information, nurse assessment details, as well as outcome data were extracted from the national NAAASP IT system, AAA SMaRT, for analysis. Some 3 026 men were referred for possible intervention (48% first screen, 52% surveillance). Some 448 men (13.3%) either declined (63, 2.1%), or were turned down for early intervention for various reasons (385, 12.7%). Some 8% were declined for medical reasons (true turn down rate). Men referred from surveillance were older, and more likely not to have had elective surgery within three months (16.0 vs. 11.2%; HR 1.37, 95% CI 1.07–1.75, p = .011). Turn down rates did not vary among local programmes, when surveillance men were taken into account. Some 2 624 (87%) men had planned AAA repair, with a peri-operative mortality of 1.3%. Thirty day surgical mortality was lower after EVAR: 0.4% compared with 2.1% after open repair. The method of repair remained consistent year on year, with roughly equal numbers undergoing endovascular (50%) and open surgical repair (48%); 2% unknown. There was regional variation in the proportion treated by endovascular repair: from 20% to 97%. The turn down rate after referral for treatment with a screen detected AAA was low, but there remains considerable regional variation in the proportion undergoing endovascular repair. Procedures were undertaken with low peri-operative mortality.

Outcomes in Men From the NHS Abdominal Aortic Aneurysm Screening Programme With a Large Aneurysm Referred for Intervention

The NHS Abdominal Aortic Aneurysm Screening Programme (NAAASP) has been implemented since 2013. Men with a large aneurysm >54mm, either at first screen or during surveillance, are referred for intervention. The aim of the present study was to explore outcomes in these men and to see whether there was any regional variation in treatment rates and type of repair. The study cohort included all men referred to a vascular network with a large abdominal aortic aneurysm (AAA). Basic demographic information, nurse assessment details, as well as outcome data were extracted from the national NAAASP IT system, AAA SMaRT, for analysis. Some 3 026 men were referred for possible intervention (48% first screen, 52% surveillance). Some 448 men (13.3%) either declined (63, 2.1%), or were turned down for early intervention for various reasons (385, 12.7%). Some 8% were declined for medical reasons (true turn down rate). Men referred from surveillance were older, and more likely not to have had elective surgery within three months (16.0 vs. 11.2%; HR 1.37, 95% CI 1.07-1.75, p=.011). Turn down rates did not vary among local programmes, when surveillance men were taken into account. Some 2 624 (87%) men had planned AAA repair, with a peri-operative mortality of 1.3%. Thirty day surgical mortality was lower after EVAR: 0.4% compared with 2.1% after open repair. The method of repair remained consistent year on year, with roughly equal numbers undergoing endovascular (50%) and open surgical repair (48%); 2% unknown. There was regional variation in the proportion treated by endovascular repair: from 20% to 97%. The turn down rate after referral for treatment with a screen detected AAA was low, but there remains considerable regional variation in the proportion undergoing endovascular repair. Procedures were undertaken with low peri-operative mortality.

The Subaneursymal Aorta – A Ten Year Perspective from a Single Centre

Introduction - In the NHS Abdominal Aortic Aneurysm Screening Programme (NAAASP) only patients whose aortas measure >30mm are offered follow up. Within the USA and most of Sweden the threshold is >25mm.1

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

Abdominal aortic aneurysm (AAA) screening programmes have been established for men in the UK to reduce deaths from AAA rupture. Whether or not screening should be extended to women is uncertain. To evaluate the cost-effectiveness of population screening for AAAs in women and compare a range of screening options. A discrete event simulation (DES) model was developed to provide a clinically realistic model of screening, surveillance, and elective and emergency AAA repair operations. Input parameters specifically for women were employed. The model was run for 10 million women, with parameter uncertainty addressed by probabilistic and deterministic sensitivity analyses. Population screening in the UK. Women aged ≥ 65 years, followed up to the age of 95 years. Invitation to ultrasound screening, followed by surveillance for small AAAs and elective surgical repair for large AAAs. Number of operations undertaken, AAA-related mortality, quality-adjusted life-years (QALYs), NHS costs and cost-effectiveness with annual discounting. AAA surveillance data, National Vascular Registry, Hospital Episode Statistics, trials of elective and emergency AAA surgery, and the NHS Abdominal Aortic Aneurysm Screening Programme (NAAASP). Systematic reviews of AAA prevalence and, for elective operations, suitability for endovascular aneurysm repair, non-intervention rates, operative mortality and literature reviews for other parameters. The prevalence of AAAs (aortic diameter of ≥ 3.0 cm) was estimated as 0.43% in women aged 65 years and 1.15% at age 75 years. The corresponding attendance rates following invitation to screening were estimated as 73% and 62%, respectively. The base-case model adopted the same age at screening (65 years), definition of an AAA (diameter of ≥ 3.0 cm), surveillance intervals (1 year for AAAs with diameter of 3.0-4.4 cm, 3 months for AAAs with diameter of 4.5-5.4 cm) and AAA diameter for consideration of surgery (5.5 cm) as in NAAASP for men. Per woman invited to screening, the estimated gain in QALYs was 0.00110, and the incremental cost was £33.99. This gave an incremental cost-effectiveness ratio (ICER) of £31,000 per QALY gained. The corresponding incremental net monetary benefit at a threshold of £20,000 per QALY gained was -£12.03 (95% uncertainty interval -£27.88 to £22.12). Almost no sensitivity analyses brought the ICER below £20,000 per QALY gained; an exception was doubling the AAA prevalence to 0.86%, which resulted in an ICER of £13,000. Alternative screening options (increasing the screening age to 70 years, lowering the threshold for considering surgery to diameters of 5.0 cm or 4.5 cm, lowering the diameter defining an AAA in women to 2.5 cm and lengthening the surveillance intervals for the smallest AAAs) did not bring the ICER below £20,000 per QALY gained when considered either singly or in combination. The model for women was not directly validated against empirical data. Some parameters were poorly estimated, potentially lacking relevance or unavailable for women. The accepted criteria for a population-based AAA screening programme in women are not currently met. A large-scale study is needed of the exact aortic size distribution for women screened at relevant ages. The DES model can be adapted to evaluate screening options in men. This study is registered as PROSPERO CRD42015020444 and CRD42016043227. The National Institute for Health Research Health Technology Assessment programme.

Self-referral to the NHS Abdominal Aortic Aneurysm Screening Programme

The NHS Abdominal Aortic Screening Programme (NAAASP) invites men in their 65th year for screening, men over 65 may self-refer into the programme. Most studies have concentrated on those invited for screening, little is known about the self-referral group. Our aim was to provide a descriptive analysis of the men who self refer to NAAASP for screening. Information concerning basic demographic details and ultrasound results were recorded on the AAA SMaRT database. During nurse assessment data collected included smoking status, blood pressure, height, weight, and aspirin and statin therapy. Statistical analysis was performed using SPSS®20. A total of 58,999 men have self-referred to the NAAASP since its inception. The mean age at self-referral was 73 (47–100). The mean aortic diameter was 1.9 cm (0.8–12.1). Increased self-referral rates were observed following organised publicity. The incidence of AAA was 4.1% (n = 2438) compared with 1.4% in the invited cohort (age 65 years), of these 7.6% (n = 186) were >5.5 cm. Of the 186, 152 (81.7%) underwent surgery, of which 55.3% (n = 84) underwent EVAR. The 30-day mortality in the men treated electively was 0%. The mean time from referral to surgery was 69 (2–361) days, with 57.9% (n = 88) being treated within 8 weeks of detection. Self-referral has yielded higher detection rates than the invited cohort, more than justifying its cost. Now that NAAASP is fully operational it is important to continue media campaigns and publicity to target the “at-risk” men over 65 who would otherwise miss the benefits of AAA screening. Some key areas still need to be addressed.

Commentary on ‘Self Referral to the NHS Abdominal Aortic Aneurysm Screening Programme’

Commentary on ‘Self Referral to the NHS Abdominal Aortic Aneurysm Screening Programme’

IF01. First Million Men Screened in the NHS Abdominal Aortic Aneurysm Screening Programme in England

IF01. First Million Men Screened in the NHS Abdominal Aortic Aneurysm Screening Programme in England

Editor's Choice – Self-referral to the NHS Abdominal Aortic Aneurysm Screening Programme

The NHS Abdominal Aortic Screening Programme (NAAASP) invites men in their 65th year for screening, men over 65 may self-refer into the programme. Most studies have concentrated on those invited for screening, little is known about the self-referral group. Our aim was to provide a descriptive analysis of the men who self refer to NAAASP for screening. Information concerning basic demographic details and ultrasound results were recorded on the AAA SMaRT database. During nurse assessment data collected included smoking status, blood pressure, height, weight, and aspirin and statin therapy. Statistical analysis was performed using SPSS(®)20. A total of 58,999 men have self-referred to the NAAASP since its inception. The mean age at self-referral was 73 (47-100). The mean aortic diameter was 1.9cm (0.8-12.1). Increased self-referral rates were observed following organised publicity. The incidence of AAA was 4.1% (n=2438) compared with 1.4% in the invited cohort (age 65 years), of these 7.6% (n=186) were >5.5cm. Of the 186, 152 (81.7%) underwent surgery, of which 55.3% (n=84) underwent EVAR. The 30-day mortality in the men treated electively was 0%. The mean time from referral to surgery was 69 (2-361) days, with 57.9% (n=88) being treated within 8 weeks of detection. Self-referral has yielded higher detection rates than the invited cohort, more than justifying its cost. Now that NAAASP is fully operational it is important to continue media campaigns and publicity to target the "at-risk" men over 65 who would otherwise miss the benefits of AAA screening. Some key areas still need to be addressed.

Abdominal Aortic Aneurysm Diameters: A Study on the Discrepancy between Inner to Inner and Outer to Outer Measurements

The NHS Abdominal Aortic Aneurysm Screening Programme (NAAASP) uses the maximal anterior to posterior (AP) inner-to-inner (ITI) wall diameter in sizing aortic dimensions when screening with ultrasound. It is recognised that ITI measurements are smaller than outer-to-outer (OTO) measurements, and the primary aim was to calculate the absolute difference in AP ITI and OTO measurements across varying aortic diameters. The secondary aim was to estimate the potential number of patients lost from the screening programme. Since April 2012, patients outside the screening programme that undergo ultrasound of abdominal aortas have their ITI and OTO measurements recorded. These measurements were compared retrospectively and analysed for variability at threshold sizes of AAAs. From May 2012 to October 2013, 452 abdominal aortic ultransound scans recorded both ITI and OTO measurements. The majority (81%) were performed on men with the mean age of 78 years. The mean difference between ITI and OTO measurements was 4.21 mm (p < .001). There was no difference between the genders. Thresholds were created for analysis between different ITI and OTO aortic diameters; these were <3 cm, 3.1-4 cm, 4.1-5 cm, and >5 cm. There was no significant difference between the means at each threshold size for ITI diameter (p = .758). In the first 2 years from April 2012, 15,447 men underwent screening.Of these, 177 (1.14%) had sub-threshold ITI aortic diameters between 2.6 cm and 2.9 cm. This would upscale to 5,316 men nationally. We have demonstrated a consistent and significant 4mm difference between ITI and OTO diameters in live scanning. Lowering the threshold for entry into a surveillance AAAs to an ITI diameter of 26mm rather than the current 30 mm is advocated. An alternative cost-effective way is to rescreen this small sub-group at 5 or 7 years.

Ultrasound Measurement for Abdominal Aortic Aneurysm Screening: A Direct Comparison of the Three Leading Methods

Ultrasound (US) is non-invasive and cost-effective for screening abdominal aortic aneurysms (AAAs) but there is no universally accepted method to measure the aortic diameter. This study evaluates the accuracy, reproducibility, and repeatability of three methods: inner-to-inner (ITI), leading-to-leading edge (LTL), and outer-to-outer (OTO). The secondary objective of this study was to determine whether aneurysm size or grade of operator had any effect on either intra- or inter-observer variability. Fifty static US images were measured by six assessors (2 vascular radiologists, 2 interventional radiology trainees, and 2 sonographers) on two separate occasions 6 weeks apart. Repeatability and reproducibility were calculated and compared with computed tomography (CT) as the gold standard. All three methods have high repeatability and reproducibility when static images are used. The inter-observer reproducibility coefficients between assessors were 0.48cm, 0.35cm, and 0.34cm for ITI, LTL and OTO, respectively. The intra-observer repeatability coefficients between assessors were 0.30cm, 0.20cm, and 0.19cm for ITI, LTL and OTO, respectively. The mean difference between CT and OTO, LTL, and ITI was 1mm, 3mm, and 5mm, respectively (all underestimations) (p<.0001). US consistently underestimates aortic size when compared with CT, with ITI demonstrating the greatest underestimation (on average 5mm). In the UK, this underestimation by the NHS Abdominal Aortic Aneurysm screening programme reduces the sensitivity of the screening test and may impact on the way in which vascular specialists interpret the findings of the screening programme.

Reliability of aortic aneurysm screening measurements.

The aim of this feasibility study was to assess the impact that image processing of abdominal aortic ultrasound (US) images had on the intra-observer reliability of the diameter measurement. The study compared variability between inner-to-inner (ITI), outer-to-outer (OTO) and outer-to-inner (OTI) wall diameter measurements and their resilience to image processing. Three US images of transverse abdominal aortas were manipulated in 13 different ways using functions from Image J software (National Institutes of Health, Bethesda, MD, USA). Blinded measurements were performed of the aortic diameters from each image; this was repeated for ITI, OTO and OTI. Profiles of each image were produced and sets of rules developed to provide detailed instructions as to where, on the profile, the callipers should be placed to correspond with the actual image. The reliability of the diameter measurements compared to the original diameter measurement was least affected by adjusting the brightness and contrast of the US images (better than ± 1.5 mm). Using the functions 'Sharpen' and 'Find Edges' created the largest difference (up to -5 mm). The ITI measurements had the widest spread of variability, whereas the OTI measurements proved to be the most repeatable and resilient to image processing. This study suggests the precision of the measurements can be kept within satisfactory levels even after image manipulation. It also showed the most reliable measuring guideline was OTI, in contrast to the guideline currently used by the NHS Abdominal Aortic Aneurysm Screening Programme. Further research is needed to transfer the findings into the clinical setting of the National Screening Programme to increase its reliability.

The Impact of Decreasing Abdominal Aortic Aneurysm Prevalence on a Local Aneurysm Screening Programme

ObjectivesThe NHS Abdominal Aortic Aneurysm Screening Programme (NAAASP), based on the Multicentre Aneurysm Screening Study (MASS) trial (2002), is being introduced across the UK. Recent studies have demonstrated a decline in prevalence of abdominal aortic aneurysm (AAA). The aim of this study was to examine the effect of this on screening workload. MethodsA model was developed to predict screening and surgical workload for a screening centre (Bristol – population 1,123,203). Workload was compared using data from MASS with data from the “Early Implementers” (EI) of NAAASP. ResultsModelling for 2011/2012 using EI data predicted significantly fewer men diagnosed with an AAA compared to MASS data [84 (EI) versus 198 (MASS) p < 0.0001] and fewer referrals to a vascular surgeon for AAA repair [10 (EI) versus 30 (MASS) p = 0.0002). This difference became more marked with time (2015/16: 90 (EI) versus 212 (MASS) men diagnosed with an AAA (p < 0.0001) and 29 (EI) versus 71 (MASS) referred to a vascular surgeon (p < 0.0001)). From 2015/16 there was also a significant reduction in the predicted number of ultrasound scans. ConclusionsModelling screening activity based on contemporary epidemiological data demonstrates a significant reduction in workload compared to MASS data. This has implications for workforce planning, the introduction of new screening centres and the future of NAAASP.

Thank you and Farewell

This is my last editorial as I hand over the reins of Ultrasound to Hazel Edwards, Consultant Sonographer at the Norwich Radiology Academy. Fortunately, Hazel shares my unnatural passion for journal editing. With her unfailing enthusiasm, wit and dedication to the journal I am confident that Ultrasound will go from strength to strength. I hope readers will agree that the journal has improved in appearance, quality and relevance over the last two years. I particularly enjoyed running the competition for best postgraduate journal article; many thanks to all the early-stage researchers who submitted their research. In continuing the journal Hazel will be aided by two new Deputy Editors, Jacinta Browne (Lecturer in Physics at Dublin Institute of Technology) and Diane DeFriend (Consultant Radiologist at Derriford Hospital in Plymouth). This line-up completes our sonographer–scientist–clinician triad and retains the interdisciplinary spirit of the British Medical Ultrasound Society (BMUS). I am delighted to welcome Jacinta and Diane and to thank Tom Fitzgerald for his support as the previous Assistant Editor. While working on the journal I have incurred many debts. I am particularly indebted to Professor David Evans for being supportive of my involvement in BMUS and to my friends and colleagues in Leicester for their patience and understanding in the face of inevitable late nights and tight deadlines. The journal editorial team, contributors and reviewers have all been a joy to work with. As Editor, I benefited from the unstinting support and good humour of staff in the BMUS office as well as the wisdom of BMUS Council and the Ultrasound Editorial Board. I feel privileged to have been able to contribute to the Society and hope to continue to be involved in the next few years. Special thanks go to Paul Sidhu and Carmel Moran from the BMUS Publications Committee for graciously assisting with reviews and being unfailingly supportive, and to Kevin Martin for offering to tackle some of our most indecipherable papers. Finally, sincere gratitude to our excellent production and marketing team at the Royal Society of Medicine Press. This month sees the launch of our third special issue, which has an obstetric theme. We are grateful to Dr Trish Chudleigh from Addenbrookes for providing a detailed guest editorial illustrating our latest collection of freely available articles online. Trish introduces each paper and highlights how practice and guidelines evolve year on year. For access, please go to http://ult.rsmjournals.com/ cgi/content/full/18/3/DC1 or visit the BMUS website to browse the previous special collections dedicated to Vascular and Paediatric topics. This issue of the journal has been compiled by Hazel, and features an enticing array of articles. Details for the delivery of the NHS Abdominal Aortic Aneurysm Screening Programme are provided in a special feature by Earnshaw. The successful implementation of this essential and important screening programme is heavily reliant on recruiting, training and retaining high quality assistant practitioners. It is, therefore, reassuring to read that CPD for these staff is recognized and is high on the agenda. MacDonald provides a useful illustrated review of current and anticipated future applications of ultrasound in the management of gynaecological cancers. It is surprising to learn that few centres perform paracentesis under ultrasound guidance despite evidence indicating that those that do have reduced morbidity and hospital stays. A study by a team from Leeds and Bradford adds to mounting evidence advocating the use of steroid injection for the treatment of subacromial impingement. This study also suggests that efficacy of this technique is not improved by ultrasound guidance. This may be of interest to hard pressed departments having difficulty meeting the demand for shoulder requests. Perhaps more clinicians should be undertaking the procedure blind on some groups of patients rather than relying on radiologists. Still on a musculoskeletal theme, Clague and Bradley propose a simple and modified technique for aspiration of ganglion cysts. Main et al. describe an example of how point-of-care ultrasound expedited the diagnosis and management of a woman with pulmonary embolus. They employ this case to support the argument that the successful use of this tool is reliant on robust training and clinical governance frameworks. Case reports have a distinctly vascular theme this month. Rajayogeswaran et al. describe a mycotic aortic aneurysm as causing a tardus parvus waveform in the hepatic artery of a transplanted liver. This condition has not been identified previously in the literature. An inflammatory abdominal aortic aneurysm is the subject of a report by Smith et al., who also consider potential training implications for screening technicians. A team from Germany describes a rare case of multiple hepatic artery aneurysms demonstrated beautifully by correlates from a range of imaging techniques. A rare disease which seems to be enjoying a revival is highlighted by a team from Edinburgh. Lemierre’s

Use of inner versus outer wall for assessing abdominal aortic aneurysm size

We read the article by Thapar et al. with interest and have a number of concerns regarding the methodology used in their study. From the article, it is not clear whether the clinical vascular scientists who took part were formally trained in the two methods of aorta/aneurysm diameter measurements. If the vascular scientists had a preference for one method of measurement in their routine practice, then this would bias the outcome of their measurements. Sonographers in the NHS Abdominal Aortic Aneurysm Screening Programme (AAASP) undergo formal training and the issue of placement of measurement calipers (particularly in identifying thrombus where confusion can arise) is carefully addressed. Therefore, it would be more valid if the sonographers in this study had been compared with those fully accredited by the NHSAAASP. We also have concern about the capture of the image used in Figure 2, given by the authors as an example of ultrasound diameter measurement. This image would fail the quality assurance requirements of the NHSAAASP with particular respect to the excessively high gain used at the posterior wall of the aneurysm. This makes it almost impossible to identify either the outer or inner wall. There is currently much debate on which method of AAA measurement is more reliable. We feel that effort should be made to ensure that correct methodology is used before discrediting one or the other method.