A single normal ultrasonographic scan at age 65 years rules out significant aneurysm disease for life in men

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.

Primary Care Screening for Abdominal Aortic Aneurysm: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Ruptured abdominal aortic aneurysms (AAAs) have mortality estimated at 81%.

OBJECTIVE

To systematically review the evidence on benefits and harms of AAA screening and small aneurysm treatment to inform the US Preventive Services Task Force.

DATA SOURCES

MEDLINE, PubMed (publisher supplied only), Database of Abstracts of Reviews of Effects, and Cochrane Central Register of Controlled Trials for relevant English-language studies published through September 2018. Surveillance continued through July 2019.

STUDY SELECTION

Trials of AAA screening benefits and harms; trials and cohort studies of small (3.0-5.4 cm) AAA treatment benefits and harms.

DATA EXTRACTION AND SYNTHESIS

Two investigators independently reviewed abstracts and full-text articles and extracted data. The Peto method was used to pool odds ratios (ORs) for AAA-related mortality, rupture, and operations; the DerSimonian and Laird random-effects model was used to pool calculated risk ratios for all-cause mortality.

MAIN OUTCOMES AND MEASURES

AAA and all-cause mortality; AAA rupture; treatment complications.

RESULTS

Fifty studies (N = 323 279) met inclusion criteria. Meta-analysis of population-based randomized clinical trials (RCTs) estimated that a screening invitation to men 65 years or older was associated with a reduction in AAA-related mortality over 12 to 15 years (OR, 0.65 [95% CI, 0.57-0.74]; 4 RCTs [n = 124 926]), AAA-related ruptures over 12 to 15 years (OR, 0.62 [95% CI, 0.55-0.70]; 4 RCTs [n = 124 929]), and emergency surgical procedures over 4 to 15 years (OR, 0.57 [95% CI, 0.48-0.68]; 5 RCTS [n = 175 085]). In contrast, no significant association with all-cause mortality benefit was seen at 12- to 15-year follow-up (relative risk, 0.99 [95% CI 0.98-1.00]; 4 RCTs [n = 124 929]). One-time screening was associated with significantly more procedures over 4 to 15 years in the invited group compared with the control group (OR, 1.44 [95% CI, 1.34-1.55]; 5 RCTs [n = 175 085]). Four trials (n = 3314) of small aneurysm surgical treatment demonstrated no significant difference in AAA-related mortality or all-cause mortality compared with surveillance over 1.7 to 12 years. These 4 early surgery trials showed a substantial increase in procedures in the early surgery group. For small aneurysm treatment, registry data (3 studies [n = 14 424]) showed that women had higher surgical complications and postoperative mortality compared with men.

CONCLUSIONS AND RELEVANCE

One-time AAA screening in men 65 years or older was associated with decreased AAA-related mortality and rupture rates but was not associated with all-cause mortality benefit. Higher rates of elective surgery but no long-term differences in quality of life resulted from screening.

Prevalence and natural history of and risk factors for subaneurysmal aorta among 65-year-old men

Background: The aims of this study were to determine the prevalence of screening-detected subaneurysmal aorta (SAA), i.e. an aortic diameter of 2.5-2.9 cm, its associated risk factors, and natural history among 65-year-old men. Methods: A total of 14,620 men had their abdominal aortas screened with ultrasound and completed a health questionnaire containing information on smoking habits and medical history. They were categorized based on the aortic diameter: normal aorta (<2.5 cm; n = 14,129), SAA (2.5-2.9 cm; n = 258), and abdominal aortic aneurysm (AAA) (≥3.0 cm; n = 233). The SAA-group was rescanned after 5 years. Associated risk factors were analyzed. Results: The SAA-prevalence was 1.9% (95% confidence interval 1.7%-2.1%), with 57.0% (50.7%-63.3%) expanding to ≥3.0 cm within 5 years. Frequency of smoking, coronary artery disease, hypertension, hyperlipidemia, and claudication were significantly higher in those with SAA and AAA compared to those with normal aortic diameter. Current smoking was the strongest risk factor for SAA (odds ratio [OR] 2.8; P < 0.001) and even stronger for AAA (OR 3.6; P < 0.001). Men with SAA expanding to AAA within 5 years presented pronounced similarities to AAA at baseline. Conclusions: Men with SAA and AAA presented marked similarities in the risk factor profile. Smoking was the strongest risk factor with an incremental association with disease severity, and disease progression. This indicates that SAA and AAA may have the same pathophysiological origin and that SAA should be considered as an early stage of aneurysm formation. Further research on the cost-effectiveness and potential benefits of surveillance as well as smoking cessation and secondary cardiovascular prevention in this subgroup is warranted.

Screening Program of Abdominal Aortic Aneurysm

In Europe, the prevalence of abdominal aortic aneurysms (AAAs) in the elderly population (≥65 year old) has declined in the past decades to <4%. Aneurysmal degeneration of the aorta is a serious and potentially life-threatening vascular disease. Abdominal aortic aneurysms typically develop subclinically and often only become symptomatic when complicated by impending rupture. Most AAAs are discovered incidentally while investigating for an unrelated pathology. Ruptured AAA is the tenth leading cause of death in Belgium (0.32% of all deaths in 2014). Health-care providers have emphasized the importance of early detection of AAA and elective repair when the rupture risk outweighs operative risk (usual diameter threshold of 55 mm). Routine AAA screening programs, consisting of a single abdominal ultrasonography at the age of 65 years, aim to reduce the number of AAA-related deaths. Does population-based ultrasound screening for AAA achieve its objective and is it cost-effective? This literature review tries to answer these challenging questions.

Lessons learned about prevalence and growth rates of abdominal aortic aneurysms from a 25-year ultrasound population screening programme

Background

This study aimed to assess how the prevalence and growth rates of small and medium abdominal aortic aneurysms (AAAs) (3·0–5·4 cm) have changed over time in men aged 65 years, and to evaluate long-term outcomes in men whose aortic diameter is 2·6–2·9 cm (subaneurysmal), and below the standard threshold for most surveillance programmes.

Methods

The Gloucestershire Aneurysm Screening Programme (GASP) started in 1990. Men aged 65 years with an aortic diameter of 2·6–5·4 cm, measured by ultrasonography using the inner to inner wall method, were included in surveillance. Aortic diameter growth rates were estimated separately for men who initially had a subaneurysmal aorta, and those who had a small or medium AAA, using mixed-effects models.

Results

Since 1990, 81 150 men had ultrasound screening for AAA (uptake 80·7 per cent), of whom 2795 had an aortic diameter of 2·6–5·4 cm. The prevalence of screen-detected AAA of 3·0 cm or larger decreased from 5·0 per cent in 1991 to 1·3 per cent in 2015. There was no evidence of a change in AAA growth rates during this time. Of men who initially had a subaneurysmal aorta, 57·6 (95 per cent c.i. 54·4 to 60·7) per cent were estimated to develop an AAA of 3·0 cm or larger within 5 years of the initial scan, and 28·0 (24·2 to 31·8) per cent to develop a large AAA (at least 5·5 cm) within 15 years.

Conclusion

The prevalence of screen-detected small and medium AAAs has decreased over the past 25 years, but growth rates have remained similar. Men with a subaneurysmal aorta at age 65 years have a substantial risk of developing a large AAA by the age of 80 years.

Screening for Abdominal Aortic Aneurysms: The Effects of Age and Social Deprivation on Screening Uptake, Prevalence and Attendance at Follow-Up in the MASS Trial

Objectives/setting:

The effectiveness of screening programmes may be improved by knowledge of factors affecting screening uptake, disease prevalence and attendance for follow-up. Data from the Multicentre Aneurysm Screening Study (MASS) are used to examine the influences of age and social deprivation in the context of screening for abdominal aortic aneurysms (AAAs).

Methods:

In the MASS trial, a population-based sample of 34,000 men aged 65 to 74 received an invitation to screening. The associations of attendance at screening with age, social deprivation and season of the year when invited to attend were investigated using logistic regression analysis. Similar analyses were performed for AAA prevalence and attendance at recall scans.

Results:

Compared with men aged 65–69, those aged 70–74 were less likely to attend screening (79% vs 81 %), had increased prevalence of AAA (6% vs 4%) and were less likely to attend for followup (79% vs 84%). Compared with those in the least deprived quartile, those in the most deprived quartile also were less likely to attend (75% vs 85%), had increased prevalence (6% vs 4%) and were less likely to attend for follow-up (80% vs 83%). Season showed no significant association with attendance at initial screening.

Conclusions:

Higher age and social deprivation are associated with both poorer attendance at screening and follow-up, and having an AAA. This highlights the importance of promoting screening programmes, particularly to the more deprived populations.

Microarray-based Gene Expression Profiling of Abdominal Aortic Aneurysm

OBJECTIVE/BACKGROUND

Microarray-based gene expression profiling studies may detect transcriptional signatures carrying prognostic value in abdominal aortic aneurysms (AAA). A gene expression profiling study was conducted to compare individuals with AAA with screened controls.

METHODS

The peripheral blood transcriptome was compared between 12 individuals with AAA and 12 age- and sex-matched controls using microarray. Validation by Taqman real-time quantitative (qPCR) was performed in an independent group as described. Peripheral blood RNA was hybridized to Illumina microarrays, each representing 37,846 genes, allowing comparison of gene expression between cases and controls. Eleven differentially expressed genes were re-quantified by qPCR in the independent group with AAA (n = 95), controls (n = 92), pre- and postendovascular AAA repair (EVAR, n = 31); or open AAA repair (n = 13), AAA wall biopsies (n = 11), and in matched smooth muscle cultures (n = 7).

RESULTS

Microarray detected 47 significantly differentially expressed genes in AAA after correction for multiple testing (p < .05). These genes conferred roles in regulation of apoptosis, proteolysis, the electron transport chain, leukocyte migration, and the humoral immune response. Gene quantification in the independent group demonstrated three genes to be downregulated in AAA compared with controls: MSN, PSMB10, and STIM1; however, their expression remained unchanged post-AAA repair. PSMB10 was the only gene conferring a consistent direction of effect in both the discovery and validation analyses (downregulated). EIF3G, SIVA, PUF60, CYC1, FIBP, and CARD8 were downregulated post-EVAR. Expression of all 11 genes of interest was detected in aortic biopsies and matched smooth muscle cultures.

CONCLUSION

This study demonstrates differential expression of transcripts in peripheral blood of individuals with AAA, with functional roles in proteolysis, inflammation, and apoptotic processes. These were modulated by aneurysm exclusion from the circulation and expressed in matched aortic biopsies and smooth muscle cultures. These observations further support the key roles for these pathways in the pathogenesis of AAA.

Does a normal screening ultrasound of the abdominal aorta reduce the likelihood of rupture in emergency department patients?

INTRODUCTION

Abdominal aortic aneurysm (AAA) development is a multifactorial process that is more prevalent among people ≥65years of age. Major risk factors are obesity, male sex, history of smoking (at least 100 cigarettes in a person's lifetime), and history of AAA in a first-degree relative. The United States Preventative Task Force has recommended a one-time ultrasound screening for men aged 65-75years. Based on studies, negative results on a single ultrasound examination around the age of 65years appear to virtually exclude the risk for future AAA rupture or death. While ultrasonography (US) is the confirmatory study of choice, computed tomography (CT) can also be used in the diagnosis of AAA. The goal of this study is to determine if AAA rupture can reliably be excluded in individuals with abdominal pain who have had a normal caliber aorta on CT or US after the age of 65years.

MATERIALS AND METHODS

A retrospective study (approved by institutional review board) of emergency department (ED) patients in an urban academic center was performed. Subjects were included if they met the following criteria: age ≥65years; an initial CT or US as an ED patient, inpatient, or outpatient for any indication, which identified an abdominal aorta <3cm; and a second CT or US during an ED visit. The incidence of ruptured AAA on the second CT or US with a history of normal aortic caliber was identified.

RESULTS

During the study period, 606 subjects were enrolled. Demographic data are listed in Table 1. Three subjects (0.5%) exhibited an abnormal-sized aorta on ED evaluation. None of these three subjects had an AAA intervention. The average size of the abnormal aorta in these three subjects was 3.3cm (S.D. 0.17).

CONCLUSION

Based on these results, it appears that AAA and rupture may reliably be excluded in ED patients with abdominal pain who have previously had a normal caliber aorta on CT or US after the age of 65years. A prospective, multicenter study would help validate these findings.

Screening for abdominal aortic aneurysm

Guidelines are systematically developed statements to assist patients and providers in choosing appropriate health care for specific clinical conditions. Consensus exists across guidelines on one-time screening of elderly men to detect and treat abdominal aortic aneurysm (AAA) ≥5.5 cm. However, the recommendations regarding other age groups, imaging intervals for small AAAs, inclusion of women, and cost-effectiveness have not been universally adopted. As many countries are considering the initiation of an AAA screening program, this is an overview on the current status of such programs.

Twenty-year review of abdominal aortic aneurysm screening in men in the county of Gloucestershire, United Kingdom

OBJECTIVE

An ultrasound screening program for abdominal aortic aneurysms (AAAs) in men began in Gloucestershire in 1990 and has been running for 20 years. This report examines the workload and results.

METHODS

We reviewed the screening database for attendance and outcome records from AAA surgery in Gloucestershire and postmortem and death certificate results looking for men who died from ruptured AAAs in the screening cohort. The setting was an AAA screening program in the county of Gloucestershire, UK. Men aged 65 were invited by year of birth to attend for an ultrasound screening for AAAs. Men with an aorta <2.6 cm were reassured and discharged; men with an aorta between 2.6 cm and 5.4 cm were offered follow-up surveillance; men with an aorta >5.4 cm were considered for intervention. We analyzed attendance rates, screening and surveillance outcomes, and intervention rates and outcomes over the 20 years of the study.

RESULTS

Some 61,982 men were invited, and 52,690 attended for screening (85% attendance). At first scan, 50,130 men (95.14%) had an aortic diameter <2.6 cm in diameter and were reassured and discharged; 148 men (0.28%) had an AAA >5.4 cm in diameter and were referred for possible treatment; 2412 (4.57%) had an aortic diameter between 2.6 and 5.4 cm and entered a program of ultrasound surveillance. The overall mean aortic diameter on initial scan fell from 2.1 cm to 1.7 cm during the study (reduction 0.015 cm/y, 95% confidence interval [CI], 0.0144-0.0156 cm/y; P < .0001). Some 631 patients with AAAs had intervention treatment with a perioperative mortality rate of 3.9%; during the same interval, 372 AAAs detected incidentally were treated, with a mortality rate of 6.7%. The number of ruptured AAAs treated annually in Gloucestershire fell during the study (χ(2) for trend = 18.31, df = 1; P < .0001).

CONCLUSIONS

Screening reduced the number of ruptured AAAs in Gloucestershire during the 20 years of the program. There has been a significant reduction of men with an abnormal aorta, as the mean aortic diameter of the 65-year-old male has reduced over 20 years.

Screening for abdominal aortic aneurysms

Ruptured AAA ranks as the 15th leading cause of death overall in the United States, and the 10th leading cause of death in men older than 55 years. Early identification of AAA can save livesand diminish cost. Screening programs havebeen implemented and studied in other countries and have shown a measurable and significant reduction in overall rate of aneurysm-related death. Currently, one-time screening of a small number of ever-smoking men when they turn 65 screening is not widely used in the United States and Medicare, at best, provides one-time screening of a small number of ever-smoking men when they turn 65 years old. Because more than 30,000 individuals in the United States die each year of ruptured AAA, a great deal of progress must be made to eradicate rupture from aneurysmal disease. A more comprehensive system of screening is required and this should be uniformly applied to the U.S. population. It is hoped that scoring systems such as the one outlined in this article, if widely adopted, can greatly enhance screening for aneurysmal disease and prevent the high mortality that stems from this serious vascular disease.

First-year results of a national abdominal aortic aneurysm screening programme in a single centre

Background

The UK Multicentre Aneurysm Screening Study (MASS) demonstrated reduced mortality from screening for abdominal aortic aneurysm (AAA). As a result, the National Health Service AAA Screening Programme was introduced in England. This study reports the results from an early-implementation screening centre.

Methods

Men aged 65 years were invited to attend an ultrasound assessment. Data were analysed for 15 months from the onset of the screening programme.

Results

A total of 6091 men aged 65 years were invited between April 2009 and June 2010, of whom 2037 (33·4 per cent) failed to attend. There were 162 self-referrals (median age 71·3 years) so that 4216 men were screened. Of those scanned, 4146 (98·3 per cent) had an aortic diameter of less than 3·0 cm, 65 (1·5 per cent) had an aneurysm measuring 3·0–5·4 cm, and five (0·1 per cent) had an aneurysm with a diameter of 5·5 cm and above. The presence of an aneurysm was more common in those who self-referred than in the invited group (P &lt; 0·001). All 70 screen-detected aneurysms were found in white men.

Conclusion

The prevalence of AAA was lower than expected. This reflects the younger age of this cohort compared with those in published large multicentre studies and the diverse ethnic background of the local population. Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.

Reproducibility of ultrasound measurement of the abdominal aorta

BACKGROUND

Abdominal aortic aneurysm (AAA) screening and surveillance programmes use ultrasound imaging to measure the anteroposterior (AP) diameter of the infrarenal aorta. The aim of this study was to examine potential observer bias and variability in ultrasound measurements.

METHODS

Studies were identified for review via a MEDLINE database search (1966-2009). References supplied in accessed papers were also checked for potential relevance. Consistent search terminology, and inclusion and exclusion criteria were used to ensure quality of data. Nine papers were available to review.

RESULTS

Variation in intraobserver repeatability and interobserver reproducibility was identified. Six studies reported intraobserver repeatability coefficients for AP aortic diameter measurements of 1·6-4·4 mm. These were below the 5-mm level regarded as acceptable by the UK and USA AAA screening programmes. Five studies had interobserver reproducibility below the level of 5 mm. Four studies, however, reported poor reproducibility (range from -2 to +5·2 to -10·5 to +10·4); these differences may have had a significant clinical impact on screening and surveillance.

CONCLUSION

The studies used different methodologies with no standardized measurement techniques. Measurements were taken by observers from different medical disciplines of varying grade and levels of training. Standard training and formal quality assurance of ultrasound measurements are important components of an effective AAA screening programme.

Low prevalence of abdominal aortic aneurysm among 65-year-old Swedish men indicates a change in the epidemiology of the disease

BACKGROUND

Screening elderly men with ultrasound is an established method to reduce mortality from ruptured abdominal aortic aneurysm (AAA; Evidence Level 1a). Such programs are being implemented and generally consist of a single scan at 65 years of age. We report the results from screening 65-year-old men for AAA in middle Sweden.

METHODS AND RESULTS

All 65-year-old men (n=26,256), identified through the National Population Registry, were invited to an ultrasound examination. An AAA was defined as a maximum infrarenal aortic diameter of ≥30 mm. In total, 22 187 (85%) accepted, and 373 AAAs were detected (1.7%; 95% confidence interval, 1.5 to 1.9). With 127 previously known AAAs (repaired/under surveillance) included, the total prevalence of the disease in the population was 2.2% (95% confidence interval, 2.0 to 2.4). Self-reported smoking (odds ratio, 3.4; P<0.001), coronary artery disease (odds ratio, 2.0; P<0.001), and hypertension (odds ratio, 1.6; P=0.001) were independently associated with AAA in a multivariate logistic regression model. Thirteen percent of the entire population reported to be current smokers, one third of the frequency reported in the 1980s. The observed low prevalence of AAA was explained mainly by this change in smoking habits.

CONCLUSIONS

On the basis of the observed reduced exposure to risk factors, lower-than-expected prevalence of AAA among 65-year-old men, unchanged AAA repair rate, and significantly improved longevity of the elderly population, the current generally agreed-on AAA screening model can be questioned. Important issues to address are the threshold diameter for follow-up, the possible need for rescreening at a higher age, and selective screening among smokers.

Abdominal aortic aneurysms, or a relatively large diameter of non-aneurysmal aortas, increase total and cardiovascular mortality: the Tromsø study

BACKGROUND

In a population-based study in Tromsø, Norway, the authors assessed whether an abdominal aortic aneurysm (AAA) or the maximal infrarenal aortic diameter in a non-aneurismal aorta influence total and cardiovascular disease (CVD) mortality.

METHODS

A total of 6640 men and women, aged 25-84 years, were included in a 10-year mortality follow-up: 345 subjects with a diagnosed AAA and 6295 subjects with a non-aneurismal aorta. Non-aneurismal aortic diameter and prevalent AAAs were categorized into seven groups.

RESULTS

In subjects without an AAA, an aortic diameter > or =30 mm increased age- and sex-adjusted total mortality [mortality rate ratio (MRR) = 3.73, 95% confidence interval (CI) 1.77-7.89] and CVD mortality (MRR = 9.24, 95% CI 4.07-20.97) compared with subjects with aortic diameter of 21-23 mm. An AAA at screening was strongly associated with deaths from aortic aneurysm and was associated with total (MRR = 1.60, 95% CI 1.31-1.96) and CVD mortality (MRR = 2.41, 95% CI 1.81-3.21). This was not explained by deaths due to an AAA. Adjustments for CVD risk factors could fully explain the increased total, but not CVD mortality in subjects with an AAA.

CONCLUSIONS

An AAA increases total and CVD mortality. In the large majority of subjects with a non-aneurysmal aorta, the diameter does not influence total or CVD mortality. However, in individuals with a maximal diameter >26 mm (2% of the population), a positive relationship is found.

Risk factors for abdominal aortic aneurysms: a 7-year prospective study: the Tromsø Study, 1994-2001

BACKGROUND

Abdominal aortic aneurysm is an asymptomatic condition with a high mortality rate related to rupture.

METHODS AND RESULTS

In a cohort of 2035 men and 2310 women in Tromsø, Norway, who were 25 to 82 years old in 1994, the authors identified risk factors for incident abdominal aortic aneurysm over the next 7 years. The impact of smoking was studied in particular. Ultrasound examination was performed initially in 1994/1995 and repeated in 2001. There were 119 incident cases of abdominal aortic aneurysms (an incidence of 0.4% per year). Male sex and increasing age were strong risk factors. In addition, the following variables were significantly associated with increased abdominal aortic aneurysm incidence: Smoking (OR=13.72, 95% CI 6.12 to 30.78, comparing current smokers of > or =20 cigarettes/d with never-smokers), hypertension (OR=1.54, 95% CI 1.03 to 2.30), hypercholesterolemia (OR=2.11, 95% CI 1.23 to 3.64, comparing subjects with serum total cholesterol > or =7.55 mmol/L with those with total cholesterol <5.85 mmol/L), and low high-density lipoprotein cholesterol (OR=3.25, 95% CI 1.68 to 6.27, comparing subjects with high-density lipoprotein cholesterol <1.25 mmol/L with those with high-density lipoprotein > or =1.83 mmol/L). In addition, use of statins was associated with increased risk of abdominal aortic aneurysm (OR=3.77, 95% CI 1.45 to 9.81), but this was probably a marker of high risk of cardiovascular diseases.

CONCLUSIONS

The results demonstrate strong associations between traditional atherosclerosis risk factors and the risk of incident abdominal aortic aneurysms.

Ultrasound surveillance of ectatic abdominal aortas

INTRODUCTION

Some studies have considered abdominal aortas of 2.6-2.9 cm diameter (ectatic aortas) at age 65 years as being abnormal and have recommended surveillance, whereas others have considered these normal and surveillance unnecessary. It is, therefore, not clear how to manage patients with an initial aortic diameter between 2.6-2.9 cm detected at screening. The aim of this study was to evaluate growth rates of ectatic aortas detected on initial ultrasound screening to determine if any developed into clinically significant abdominal aortic aneurysms (AAAs; > 5.0 cm) and clarify the appropriate surveillance intervals for these patients.

PATIENTS AND METHODS

Data were obtained from a prospective AAA screening programme which commenced in 1992. The group of patients with initial aortic diameters of 2.6-2.9 cm with a minimum of 1-year follow-up were included in this study (Group 2). This was further divided into two subgroups (Groups 3a and 3b) based on a minimum follow-up interval obtained from outcome analysis. Mean growth rate was calculated as change in aortic diameter with time. The comparison of growth rates in Groups 3a and 3b was performed using the t-test. The number and proportion of AAAs that expanded to >or= 3.0 cm and >or= 5.0 cm in diameter were also calculated.

RESULTS

Out of 999 patients with AAA >or= 2.6 cm with minimum 1-year follow-up, 358 (36%) were classified as ectatic aortas (2.6-2.9 cm) at initial ultrasound screening with the mean growth rate of 1.69 mm/year (95% CI, 1.56-1.82 mm/year) with a mean follow-up of 5.4 years. Of these 358 ectatic aortas, 314 (88%) expanded into >or= 3.0 cm, 45 (13%) expanded to >or= 5.0 cm and only 8 (2%) expanded to >or= 5.5 cm over a mean follow-up of 5.4 years (range, 1-14 years). No ectatic aortas expanded to >or= 5.0 cm within the first 4 years of surveillance. Therefore, the minimum follow-up interval was set at 4 years and this threshold was then used for further analysis. The mean growth rate in Group 3a (< 5.0 cm at last scan) was 1.33 mm/year (95% CI, 1.23-1.44 mm/year) with a mean follow-up of 7 years compared to Group 3b (>or= 5.0 cm at last scan) with the mean growth rate of 3.33 mm/year (95% CI 3.05-3.61 mm/year) and a mean follow-up of 8 years. The comparison of mean growth rates between Groups 3a and 3b is statistically significant (t-test; T = 13.00; P < 0.001).

CONCLUSIONS

One-third of patients undergoing AAA screening will have ectatic aortas (2.6-2.9 cm) and at least 13% of these will expand to a size of >or= 5.0 cm over a follow-up of 4-14 years. A threshold diameter of 2.6 cm for defining AAAs in a screening programme is recommended and ectatic aortas detected at age 65 years can be re-screened at 4 years after the initial scan. A statistically significant difference was found in the growth rates of ectatic aortas with minimum 4 years follow-up, expanding to >or= 5.0 cm compared to those less than 5.0 cm at last surveillance scan. Further studies are required to test the hypothesis of whether growth rate over the first 4 years of surveillance will identify those who are most likely to expand to a clinically significant size (> 5.0 cm).

Abdominal Aortic Aneurysms, Increasing Infrarenal Aortic Diameter, and Risk of Total Mortality and Incident Cardiovascular Disease Events

Background— Long-term data describing small abdominal aortic aneurysms (AAAs) and increasing infrarenal aortic diameters and their relationship to future surgical repair, total mortality, and incident cardiovascular disease (CVD) events, particularly among women, are sparse.

Methods and Results— In 1992 to 1993, 4734 Cardiovascular Health Study participants ≥65 years old had an abdominal aortic ultrasound evaluation. Of those screened, 416 had an AAA (infrarenal aortic diameter ≥3.0 cm or an infrarenal/suprarenal ratio ≥1.2). By 2002, there were 56 surgical AAA repairs and 10 AAA-related deaths. A single ultrasound screening demonstrated that aneurysm dilation ≥3 cm identified 68% of all AAA repairs over the next 10 years and 6 of the 10 AAA-related deaths in 4% of the total population and that a ≥2.5-cm dilation identified 91% of all AAA repairs and 9 of the 10 deaths in 10% of the total population. With adjusted Cox proportional hazard models, AAAs were associated with a higher risk of total mortality (hazard ratio 1.44, 95% confidence interval 1.25 to 1.66) and incident CVD events (hazard ratio 1.52, 95% confidence interval 1.25 to 1.85). Compared with diameters <2.0 cm, infrarenal aortic diameters 2.0 to <3.0 cm were associated with increased risk of incident CVD events in women and total mortality in men.

Conclusions— This study suggests that a 1-time screening of the abdominal aorta can acceptably identify individuals with a clinically significant AAA. Infrarenal aortic diameters >2.0 cm are associated with a significantly increased risk of future CVD events and total mortality.

The interleukin-10-1082 'A' allele and abdominal aortic aneurysms

BACKGROUND

Abdominal aortic aneurysms (AAA) are caused by inflammatory processes in the wall of the aorta resulting in degradation of structural proteins. This inflammatory process is mediated, in part, by cytokines, and interleukin-10 (IL-10) is a predominantly anti-inflammatory cytokine. A single nucleotide polymorphism in the promoter region of the IL-10 gene that affects transcription has been associated with AAA in a small study. The aim of this study was to determine whether this polymorphism is associated with AAA and also examine its effect on the growth of small AAA.

METHODS AND RESULTS

A case control study was performed. A total of 389 patients with AAA and 404 healthy controls were recruited. IL-10-1082 polymorphisms were determined by polymerase chain reaction-based methods. In the case of patients with small AAA (<5.5 cm), serial size measurements were recorded to determine mean growth rate. There was a statistically significant difference both in allele and genotype frequencies between the case and control groups with the IL-10-1082 'A' allele being more common in the AAA group (P = .006). In the AAA group, genotype frequencies were as follows: GG 84, GA 201, and AA 104. In the control group, the genotype frequencies were GG 118, GA 205, and AA 81. The odds ratio for the 'A' allele as a risk factor for AAA was 1.50 (95% confidence interval 1.09 to 2.07). Regression modeling revealed that the IL-10-1082 genotype was, however, not independently associated with AAA if age, tobacco use, hypertension, and history of coronary or peripheral artery disease was taken into account. There was a trend towards lower plasma IL-10 level in IL-10 AA carriers, but the IL-10 'A' allele did not have any discernible effect on the growth of small AAA.

CONCLUSIONS

This study demonstrates that the IL-10-1082 'A' allele is associated with AAA, although this association is likely to be secondary to an association between IL-10-1082 genotype and other markers of cardiovascular disease rather than AAA per se.

Pathology, natural history and treatment of abdominal aortic aneurysms

With increasing age of the population and improvement of diagnostic tools, the incidence of abdominal aortic aneurysms (AAA) has been rising steadily. Despite an improvement in operative and interventional treatment options, AAA is the cause of death in 1-3% of men over 65 years of age in industrial countries, mostly due to rupture [1]. Therefore, routine screening for AAA by ultrasonography has been postulated in the past: a 60 year old man with an abdominal aortic diameter of less than 3 cm has a life-time risk of developing AAA close to zero. However, routine screening has not been found to be cost effective. Despite of the results of two well-designed studies, the limits of AAA qualifying the patient for surgery or intervention in contrast to conservative treatment is still a matter of debate. The present review article summarizes the current knowledge of the pathology, incidence, risks, natural course as well as symptoms and current treatment strategies of AAA on the basis of the recent literature.

Increased natural killer cell activity in patients with an abdominal aortic aneurysm

BACKGROUND

Natural killer (NK) cells have an emerging role in the development of chronic disease and in the direction and maintenance of inflammatory responses. Abdominal aortic aneurysms (AAA) is a chronic inflammatory disorder of unknown aetiology. The aim was to investigate whether NK cells showed altered function in patients with an AAA.

METHODS

The presence, phenotype and function of peripheral blood and tissue NK cells from patients with an AAA, peripheral vascular disease (PVD) and healthy age-sex-matched controls were assessed before and after surgery.

RESULTS

Patients with an AAA had significantly higher (P < 0.010) percentages of peripheral blood NK cells (mean (95 per cent c.i.) 23.8 (2.6) per cent) than patients with PVD (17.4 (2.9) per cent) and control subjects (16.2 (2.8) per cent). The NK cells from patients with an AAA had increased cytotoxicity on a per cell basis towards both an NK-sensitive target cell line and human aortic smooth muscle cells. Increased NK cell proportions (22.7 (3.5) per cent) and cytotoxic activity, together with higher C-reactive protein values, persisted after successful AAA repair.

CONCLUSION

These data support the hypothesis that increased NK cytotoxicity could be a contributing factor in the generation or potentiation of inflammation in patients with an AAA.

Abdominal aortic aneurysm (AAA): cost-effectiveness of screening, surveillance of intermediate-sized AAA, and management of symptomatic AAA

Physicians must make decisions about screening patients for abdominal aortic aneurysms (AAAs), monitoring or referring for surgery patients with AAAs of various sizes, and assessing patients with symptoms that may be related to AAAs. This review article analyzes the evidence for each scenario. The effectiveness and cost-effectiveness of screening for AAA is based on results from four randomized controlled trials. A cost-effectiveness analysis using a Markov model showed that ultrasound screening of white men beginning at age 65 is both effective and cost-effective in preventing AAA-related death. Such screening would have a small but real impact over a 20-year period in these men. For patients with a known AAA-which is often detected incidentally-the evidence clearly suggests periodic ultrasound surveillance for those with small AAAs (3.0-3.9 cm in diameter) and elective surgical repair for those with large AAAs (>or=5.5 cm). Two recent randomized controlled trials have shown that early surgical repair confers no survival benefit compared with periodic surveillance for patients with intermediate-sized AAAs (4.0-5.5 cm in diameter), so those patients can also be monitored. Some centers choose to increase the frequency of monitoring to every 3 to 6 months when the AAA reaches 5.0 cm. Factors to consider in assessing symptomatic patients include the high risk of life-threatening conditions, the potential increased risk of death or poor outcome with delay in diagnosis, the limitations of ultrasound in identifying whether symptoms are due to known or suspected AAA, and the timely availability of computed tomography or other imaging tests. If available, computed tomography is preferred in patients with recent or severe symptoms, since it is better at detecting retroperitoneal hemorrhage and other complications and in providing preoperative definition of the anatomy.

Abdominal aortic aneurysm screening: recommendations and controversies

Extensive level one evidence supports routine abdominal aortic aneurysm (AAA) screening in men aged 65 to 75 years, because AAAs are highly prevalent in this population. Physical examination is an insensitive means of detection. Ruptured AAAs are costly with respect to quality adjusted life years (QALY) lost and medical expenses. Large scale, randomized trials have demonstrated that AAA screening reduces all AAA-related mortality in the screened population and is cost-effective in mid-term follow-up. AAA screening by ultrasound has many advantages over other accepted medical screening programs in its simplicity in structure and the availability of an inexpensive, portable, and reliable means of screening. Additionally, AAA screening almost entirely avoids the negative consequences associated with other screening programs, including the adverse psychological effects and medical costs associated with false-positive examination results. There are subgroups of at-risk women who might benefit from AAA screening, and this issue should be further studied.

Decision-analytical model with lifetime estimation of costs and health outcomes for one-time screening for abdominal aortic aneurysm in 65-year-old men

Background

Abdominal aortic aneurysm (AAA) causes about 2 per cent of all deaths in men over the age of 65 years. A major improvement in operative mortality would have little impact on total mortality, so screening for AAA has been recommended as a solution. The cost-effectiveness of a programme that invited 65-year-old men for ultrasonographic screening was compared with current clinical practice in a decision-analytical model.

Methods

In a probabilistic Markov model, costs and health outcomes of a screening programme and current clinical practice were simulated over a lifetime perspective. To populate the model with the best available evidence, data from published papers, vascular databases and primary research were used.

Results

The results of the base-case analysis showed that the incremental cost per gained life-year for a screening programme compared with current practice was €7760, and that for a quality-adjusted life-year was €9700. The probability of screening being cost-effective was high.

Conclusion

A financially and practically feasible screening programme for AAA, in which men are invited for ultrasonography in the year in which they turn 65, appears to yield positive health outcomes at a reasonable cost.

Functional characterization of T cells in abdominal aortic aneurysms

Abdominal aortic aneurysms (AAA) exhibit features of a chronic inflammatory disorder. The functional attributes of the T cells in AAA tissue are unclear, with little quantitative or functional data. Using a novel, non-enzymatic method to isolate viable cells from AAA tissue, functional properties of AAA T cells were investigated for the first time. Composition and phenotype of AAA T cells was determined by flow cytometry and verified by immunohistochemistry. Tissue mononuclear cells (MNCs) were cultured in the presence of T-cell mitogens, and cell cycle analysis and cytokine production assessed. Typical cell yield was 4.5 x 10(6) cells per gram of AAA tissue. The majority (58.1+/-5.3%) of haematopoietic (CD45+) cells recovered were CD3+ T cells, B cells comprised 41.1+/-5.7%, natural killer cells 7.3+/-2.5%, and macrophages 2%. Freshly isolated T cells were in resting (G1) state, with 25% expressing the activation-associated cell surface antigens major histocompatibility complex II and CD25. When stimulated in vitro, a significant proportion entered S and G2 phase of the cell cycle, up-regulated CD25, and secreted tumour necrosis factor-alpha, interferon-gamma, interleukin (IL)-5 and IL-6. Despite patient differences, the composition of the AAA inflammatory infiltrate was remarkably consistent, and when re-stimulated ex-vivo T cells produced a stereotypical cytokine response, consistent with the hypothesis that AAA T cells can promote tissue inflammation by secretion of proinflammatory cytokines, and in addition provide signals for B-cell help.

Cost-effectiveness of different screening strategies for abdominal aortic aneurysm

OBJECTIVE

The primary objective of this study was to develop a simulation model to assess the cost-effectiveness of different screening strategies for abdominal aortic aneurysms (AAAs) in men.

METHODS

A systematic review of the literature was conducted for different screening strategies in terms of age (60, 65, or 70 years) and risk profiles (all men or specific high-risk groups) of the screened population, and rescreening after 5 or 10 years. These data were analyzed in a Markov simulation cohort model.

RESULTS

The cost per life year gained for different screening strategies ranged from US 8,309 dollars to US 14,084 dollars and was estimated at US 10,474 dollars when 65-year-old men were screened once. Screening 60-year-old men was equally cost-effective, with the advantage of more life years gained. We demonstrated a trade-off between high prevalence of AAA and lower life expectancy, eliminating the expected benefits of screening high-risk groups such as smokers (US 10,695 dollars) or cardiovascular patients (US 10,392 dollars). Assuming general population utility resulted in a cost per quality-adjusted life year (QALY) gained of US 13,900 dollars, whereas a hypothetical 5% reduction in utility among men with a screening-detected AAA raised the cost per QALY gained to US 75,100 dollars.

CONCLUSION

This Markov model, which was based on a systematic review of the literature, supplied information on the estimated cost-effectiveness of different screening strategies. Screening men for AAA may be cost-effective in the long-term. Different screening strategies and quality-of-life effects related to screening for AAA need to be evaluated in future clinical studies.

[Long-term results after elective and emergency surgery of abdominal aortic aneurysm]

INTRODUCTION

Abdominal aortic aneurysm can be repaired by elective procedure while asymptomatic, or immediately when it is complicated--mostly due to rupture. Treating abdominal aneurysm electively, before it becomes urgent, has medical and economical reason. Today, the first month mortality after elective operations of the abdominal aorta aneurysm is less than 3%; on the other hand, significant mortality (25%-70%) has been recorded in patients operated immediately because of rupture of the abdominal aneurysm. In addition, the costs of elective surgical treatment are significantly lower.

OBJECTIVE

The objective of this study is to compare long-term survival of patients that underwent elective or immediate repair of abdominal aortic aneurysm (due to rupture), and to find out the factors influencing the long-term survival of these patients.

MATERIAL AND METHODS

Through retrospective review of prospectively collected data of the Institute for Cardiovascular Diseases of Clinical Center of Serbia, Belgrade, 56 patients that had elective surgery and 35 patients that underwent urgent operation due to rupture of abdominal aneurysm were followed up. Only the patients that survived 30 postoperative days were included in this review, and-were followed up (ranging from 2 to 126 months). Electively operated patients were followed during 58.82 months on the average (range 7 to 122), and urgently operated were followed over 52.26 months (range 2 to 126). There was no significant difference of the length of postoperative follow-up between these two groups.

RESULTS

During this period, out of electively operated and immediately operated patients, 27 and 22 cases died, respectively. There was no significant difference (p>0.05a) of long-term survival between these two groups. Obesity and early postoperative complications significantly decreased long-term survival of both electively and immediately operated patients. Graft infection, ventral hernia, aneurysm of peripheral arteries and other vascular reconstructive procedures were the factors that significantly reduced long-term survival of patients operated immediately due to rupture.

DISCUSSION

This comprehensive study has searched for more factors than others had done before. The applied discriminative analysis numerically evaluated the influence of any risk factor of mortality. These factors were divided in three groups as follows: preoperative, operative and postoperative ones. Preoperative factors were sex, age, diabetes mellitus, arterial hypertension, obesity, COPD, and naturally, the indication for operative treatment of ruptured or non-ruptured abdominal aneurysm. Among all these factors, only obesity significantly reduced long-term survival of electively operated patients. It may be said that immediately operated patients who survived the first 30 postoperative days had quite good long-term survival. Operative factors such as type of operative procedure and vascular graft had no influence on long-term survival of patients in both groups. Postoperative risk factors were early postoperative complications, graft infection, symptomatic cerebrovascular disease, carotid endarterectomy, myocardial revascularization, ventral hernias, "other" non vascular operations, malignancy, mental disorders, peripheral aneurysms and occlusive vascular disease, and other vascular operations either due to aneurysm or peripheral occlusive disease. Early postoperative complications (even graft infection) had no significant effect on long-term survival. Ventral hernias and peripheral aneurysms were factors that significantly decreased long-term survival of patients operated for rupture of the abdominal aneurysm.

CONCLUSION

It is interesting that endarterectomy, myocardial revascularization or malignancy after repair of the abdominal aneurysm (ruptured or non-ruptured) had no effect on long-term survival.

Implications of screening for abdominal aortic aneurysms on surgical workload

Background

The Multicentre Aneurysm Screening Study (MASS) provided strong evidence for both the clinical benefit and the cost-effectiveness of a screening programme for abdominal aortic aneurysms (AAAs) in men. If a national screening programme for AAA were adopted in the UK, it would be expected to increase the elective and decrease the emergency surgical workload.

Methods

The MASS trial randomized 67 800 men aged 65–74 years to be invited to attend for ultrasonographic screening for AAA or to a control group that received no invitation. Predictions of elective and emergency surgical workload were made for a 20-year interval after the introduction of a screening programme for 65-year-old men, based on surgical rates observed in the MASS trial and national mortality statistics.

Results

For a district general hospital serving a population of 400 000, there was an estimated reduction from nine emergency operations per year before introduction of the screening programme to three emergency operations annually in men aged 65 years and over by the end of the 20-year interval, and an increase from 24 to 43 AAA operations overall. The corresponding estimated annual costs for all AAA surgery increased by 47 per cent, from £209 000 to £308 000. These results were not affected by changes in the underlying assumptions.

Conclusion

The results support the expectation of very few emergency operations, and principally elective operations, being performed following the introduction of a screening programme. For a typical district general hospital, a screening programme would be expected to lead to two additional elective AAA operations per month, and to save 11 AAA-related deaths per year.

Screening, Diagnosis and Advances in Aortic Aneurysm Surgery

BACKGROUND

Aortic aneurysms are common in the elderly and a frequent cause of sudden death. As elective aneurysm repair has a mortality drastically lower than that associated with rupture, the emphasis must be on early detection and repair free from complications. Recent advances include ultrasound screening for asymptomatic abdominal aortic aneurysm (AAA) and clinical trials on the size of AAA that require repair. Pre-operative assessment, management of cardiac risk, autologous blood transfusion strategies, and endovascular stent graft technology to avoid major open surgery are all issues to be addressed.

METHODS

Following a computerized Medline search for publications on the detection and treatment of abdominal and thoracic aortic aneurysm, the publications identified were then read and the references within those publications examined for further publications on this topic. We have reviewed these publications without attempting a meta-analysis.

RESULTS

Randomized population studies have addressed ultrasound screening for AAA. Attendance for screening was good and AAA detection inexpensive. Screening men from 65 years reduces the mortality from rupture and is cost-effective. Open thoracic and abdominal aneurysm repair has a mortality of around 8%, with myocardial infarction being a frequent cause of death. Pre-operative reduction of cardiac risk by cardiac investigations and beta-blockade may reduce this mortality. Autologous transfusion techniques such as acute normovolaemic haemodilution and interoperative cell salvage reduce the need for allogeneic blood and the complications associated with open surgery. Minimally invasive endovascular repair is now possible for 40% of the AAA and an increasing proportion of thoracic aneurysms.

CONCLUSIONS

The combination of screening, reduced pre-operative risk, and new minimally invasive techniques extends aortic aneurysm treatment into an increasingly elderly population. The combination of these techniques will reduce mortality from ruptured aortic aneurysm in the elderly and also reduce the stress associated with aneurysm surgery.

Late Survival after Elective Repair of Aortic Aneurysms Detected by Screening

BACKGROUND

The aim of this study was to examine whether there was any survival advantage in men following elective repair of an abdominal aortic aneurysm (AAA) detected by ultrasound screening compared to those with an AAA detected incidentally.

METHODS

A total of 424 men underwent elective AAA repair between 1990 and 1998; 181 were detected in an aneurysm screening programme and 243 were diagnosed incidentally. Follow-up survival data were collected until 2003 (minimum 5 years) and survival curves were compared using regression analysis.

RESULTS

The postoperative 30-day mortality rate was significantly lower in men whose aneurysms were detected by screening (4.4%), compared with those detected incidentally (9.0%). Similarly, 5-year survival (78% vs. 65%) and 10-year survival rates (63% vs. 40%) were better after repair of a screen-detected AAA (p<0.0003 at all time intervals, by log rank testing). Multivariate analysis showed that this was largely due to the older age of men who had repair of an incidental AAA (71.2 vs. 67.1 years).

CONCLUSION

Men who had elective repair of an AAA detected by screening had a better late survival rate than men whose aneurysm was discovered incidentally because they were younger at the time of surgery.

Indications for operative management of abdominal aortic aneurysms

The increasing incidence of abdominal aortic aneurysms, along with the more frequent use of screening techniques, has resulted in greater numbers of patients with small abdominal aortic aneurysms. The questions of frequency of surveillance and timing of intervention are the two most controversial issues faced by surgeons dealing with this condition. Most management decisions are based on the size of the aneurysm but other factors must also be considered. This review makes recommendations on the management of small abdominal aortic aneurysms according to the current available evidence.

Screening for abdominal aortic aneurysms in men

Gloucestershire's screening project shows the potential benefits of a national programme and how it could be run

Detection, Management, and Prospects for the Medical Treatment of Small Abdominal Aortic Aneurysms

Small abdominal aortic aneurysms, up to 5.5 cm in diameter, are very common. Ultrasonography is the most cost-effective method of detecting these aneurysms and keeping them under surveillance, because the natural history is 1 of continued expansion. The expansion rate is in the range 0.25 to 0.35 cm/y and is fastest in current smokers. From a study of expansion rates, it has been possible to formulate guidelines for the intervals at which surveillance should occur. Although the evidence from randomized trials indicates that early, open, elective surgery for small aneurysms does not save lives, when aneurysms exceed 5.5 cm in diameter, either open or endovascular surgery is recommended. To prevent small aneurysms reaching the 5.5-cm threshold, new treatments to reduce the expansion rate by >50% need to be designed, based on the underlying pathologic processes: proteolysis and inflammation. Any proposed treatments, including statins, will need to be tested in clinical trials.

Recommendations for screening intervals for small aortic aneurysms

BACKGROUND

The aim was to determine the optimum rescreening interval for small abdominal aortic aneurysms (AAAs).

METHODS

Data from 12 years of population screening of 65-year-old men were analysed and 1121 small AAAs (less than 4.0 cm in initial diameter) were divided into groups: group 1 (2.6-2.9 cm; n = 625), group 2 (3.0-3.4 cm; n = 330) and group 3 (3.5-3.9 cm; n = 166). Expansion rate and the cumulative proportions to expand to over 5.5 cm, or require surgery, or rupture were calculated.

RESULTS

Expansion rate was related to initial aortic diameter: 0.09 cm per year in group 1, 0.16 cm per year in group 2 and 0.32 cm per year in group 3 (P < 0.001). Aneurysms in 2.4 per cent of patients in group 1 exceeded a diameter of 5.5 cm or required surgery within 5 years; there were no ruptures. In group 2, no aorta exceeded 5.5 cm but at 3 years 2.1 per cent had reached 5.5 cm and 2.9 per cent had required surgery. The rupture rate at 3 years was zero. In group 3, the aneurysm diameter exceeded 5.5 cm in 1.2 per cent of patients, but no patient required surgery or experienced rupture within 1 year; at 2 years 10.5 per cent of aneurysms had exceeded 5.5 cm in diameter or required surgery and 1.4 per cent had ruptured.

CONCLUSION

The appropriate rescreening interval can be determined by initial aortic diameter in screened 65-year-old men. AAAs of initial diameter 2.6-2.9 cm should be rescanned at 5 years, those of 3.0-3.4 cm at 3 years and those of 3.5-3.9 cm at 1 year.

Screening for abdominal aortic aneurysm

The case in favour of screening is made