Lower Prevalence than Expected when Screening 70-year-old Men for Abdominal Aortic Aneurysm

The association between diabetes and abdominal aortic aneurysms in men: results of two Danish screening studies, a systematic review, and a meta-analysis of population-based screening studies

BACKGROUND

A paradoxical protective effect of diabetes on the development and progression of abdominal aortic aneurysms (AAA) has been known for years. This study aimed to investigate whether the protective role of diabetes on AAAs has evolved over the years.

METHODS

A cross-sectional study, a systematic review and meta-analysis. This study was based on two large, population-based, randomised screening trials of men aged 65-74; VIVA (2008-2011) and DANCAVAS (2014-2018), including measurement of the abdominal aorta by ultrasound or CT, respectively. Analyses were performed using multiple logistic regressions to estimate the odds ratios (ORs) for AAAs in men with diabetes compared to those not having diabetes. Moreover, a systematic review and meta-analysis of population-based screening studies of AAAs to visualise a potential change of the association between diabetes and AAAs. Studies reporting only on women or Asian populations were excluded.

RESULTS

In VIVA, the prevalence of AAA was 3.3%, crude OR for AAA in men with diabetes 1.04 (95% confidence interval, CI, 0.80-1.34), and adjusted OR 0.64 (CI 0.48-0.84). In DANCAVAS, the prevalence of AAA was 4.2%, crude OR 1.44 (CI 1.11-1.87), and adjusted OR 0.78 (CI 0.59-1.04). Twenty-three studies were identified for the meta-analysis (N = 224 766). The overall crude OR was 0.90 (CI 0.77-1.05) before 2000 and 1.16 (CI 1.03-1.30) after 1999. The overall adjusted OR was 0.63 (CI 0.59-0.69) before 2000 and 0.69 (CI 0.57-0.84) after 1999.

CONCLUSION

Both the crude and adjusted OR showed a statistically non-significant trend towards an increased risk of AAA by the presence of diabetes. If this represents an actual trend, it could be due to a change in the diabetes population.

TRIAL REGISTRATION

DANCAVAS: Current Controlled Trials: ISRCTN12157806. VIVA: ClinicalTrials.gov NCT00662480.

Abdominal aortic aneurysm growth rates are not correlated to body surface area in screened men

BACKGROUND

Screening for abdominal aortic aneurysm (AAA) in 65-year-old males reduces aneurysm related mortality. Infrarenal aortic diameter (IAD) has been shown to correlate to body surface area (BSA) which could influence diagnostic criteria for AAA. This study investigates whether AAA growth rates are also dependent on BSA, as that might have potential effects on surveillance of small AAAs.

METHODS

We conducted a retrospective, single center cohort study of 301 men with screening detected AAA between 2010-2017 with surveillance to 2021. AAA growth rates were analyzed in relation to the subject's BSA, smoking habits, and diabetic disease using a linear mixed-effects model. All men were offered smoking cessation program, optimized medical treatment, and advice on physical activity.

RESULTS

The screening program included 28,784 men. Of the 22,819 (79%) attending the examinations, 374 men (1.6%) were found to have an AAA out of which 301 men had undergone two or more examinations during surveillance and were included with a median follow-up of 1846 days (IQR: 1 399). Mean unadjusted AAA growth rate was 1.60 mm/year (95% CI: 1.41-1.80). Diabetes mellitus had a statistically significant negative impact, smoking had a statistically significant positive impact on AAA growth rates whereas no correlation between AAA growth rate and BSA could be found.

CONCLUSIONS

Body surface area could not be found to have a statistically significant correlation to AAA growth rates. The impact of smoking and diabetes on AAA growth rates remains similar to previously reported.

Vasoactive Biomarkers Associated With Long-Term Incidence of Symptomatic Peripheral Arterial Disease and Mortality

We evaluated if plasma biomarkers can predict incident peripheral arterial disease (PAD) and mortality in a longitudinal cohort study. Men (n = 3618) and women (n = 1542) were included in the Malmö Preventive Project and underwent analysis of: C-terminal endothelin-1 (CT-proET-1), N-Terminal prosomatostatin (NT-proSST), midregional proatrial natriuretic peptide (MR-proANP), procalcitonin (PCT), and copeptin. Participants were followed up for incident PAD and mortality until December 31, 2016. Median follow-up was 11.2 years (interquartile range 9.4-12.2). Cumulative incidence of PAD was 4.3% (221/5160), 4.5% in men (164/3618) and 3.7% in women (57/1542; P = .174). In an adjusted Cox proportional hazards regression model, higher CT-proET-1 (hazard ratio [HR] 1.8; 95% confidence interval [CI] 1.4-2.3), NT-proSST (HR 1.5; 95% CI 1.2-2.0), and MR-proANP (HR 1.7; 95% CI 1.3-2.3) were independently associated with incident PAD, and higher CT-proET-1 (HR 1.3; 95% CI 1.2-1.5), NT-proSST (HR 1.2; 95% CI 1.1-1.3), MR-proANP (HR 1.4; 95% CI 1.3-1.6), PCT (HR 1.1; 95% CI 1.0-1.2), and copeptin (HR 1.2; 95% CI 1.1-1.4) were independently associated with mortality. Increased levels of CT-proET-1, NT-proSST, and MR-proANP were independently associated with incident PAD, whereas all the vasoactive biomarkers were independently associated with mortality during follow-up.

Screening cardiovascular patients for aortic aneurysms (SCAN) - high prevalence of abdominal aortic aneurysms in coronary heart disease patients requiring intervention

Background: Since the prevalence of abdominal aortic aneurysms (AAA) in Europe has declined to about 2.5%, general screening programs of elderly men are being called into question. On the other hand, other vascular diseases (e.g. coronary heart disease, CHD) are associated with a higher prevalence of AAA. This might have an impact on future targeted AAA screening programs. This study aimed to reevaluate the current prevalence of AAA in male patients with CHD, in order to assess whether CHD patients should be offered a targeted AAA ultrasound screening program. Patients and methods: The SCAN (Screening Cardiovascular Patients for Aortic Aneurysms) study prospectively evaluated the AAA prevalence in 1000 consecutive male CHD patients (70.1 ± 11.2 years) requiring any coronary intervention at an university hospital. All patients received transverse and longitudinal ultrasound scans of the abdominal aorta. Aortic diameter was assessed using the outer-to-outer measurement-technique. Primary endpoint was the prevalence of AAA. Secondary outcomes included stratification in 1-, 2-, or 3-vessel CHD. Results: AAA was detected in 85 patients (median diameter 38 mm, range 30-80 mm), corresponding to an overall prevalence of 8.5%. AAA prevalence was significantly associated with CHD severity: 5.6% in 1-vessel, 7.1% in 2-vessel, and 10.8% in 3-vessel CHD (P = 0.037). The multivariable analysis showed, that age per 10 years increase (OR 1.5, 95% CI 1.2-1.9, P = 0.001) and hyperlipidemia (OR 2.2, 95% CI 1.3-3.8, P = 0.003) were significantly associated with an AAA. The likelihood to be diagnosed with an AAA was significantly lower in non-smokers (OR 0.24, 95% CI, P < 0.001). Conclusions: This study confirms that CHD requiring any type of coronary intervention is strongly associated with AAA in male patients. AAA prevalence increases with CHD severity. Since the AAA prevalence is still significantly higher than in the general population, targeted ultrasound screening should be considered for all CHD patients.

Top 10 candidate aortic disease trials

Aortic pathologies such as aneurysm, dissection and trauma are relatively common and potentially fatal diseases. Over the past two decades, we have experienced unprecedented technical and medical developments in the field. Despite this, there is a great need, and great opportunities, to further explore the area. In this review, we have identified important areas that need to be further studied and selected priority aortic disease trials. There is a pressing need to update the AAA natural history and the role for endovascular AAA repair as well as to define biomarkers and genetic risk factors as well as influence of gender for development and progression of aortic disease. A key limitation of contemporary treatment strategies of AAA is the lack of therapy directed at small AAA, to prevent AAA expansion and need for surgical repair, as well as to reduce the risk for aortic rupture. Currently, the most promising potential drug candidate to slow AAA growth is metformin, and RCTs to verify or reject this hypothesis are warranted. In addition, the role of endovascular treatment for ascending pathologies and for uncomplicated type B aortic dissection needs to be clarified.

Prospective Ultrasound Screening of Men With Cerebrovascular Disease for Abdominal Aortic Aneurysms

BACKGROUND

The prevalence of abdominal aortic aneurysms is higher in population with other vascular comorbidities, especially among men. Utility of screening among patients with cerebrovascular disease is unclear.

OBJECTIVE

To determine the prevalence of abdominal aortic aneurysm in male patients with diagnosed cerebrovascular disease manifested by transient ischemic attack or stroke.

METHODS

Between May 2013 and May 2014, all consecutive male patients undergoing carotid ultrasound in single tertiary center with a catchment area of 179,000 inhabitants were evaluated for ultrasound screening of abdominal aortic aneurysm. Abdominal aortic aneurysm was defined as maximum diameter of infrarenal aorta 30 mm or more.

RESULTS

Of 105 (n = 105) consecutively evaluated male patients, only 69% (n = 72) were eligible for the study and underwent aortic screening. Reason for ineligibility was most often poor general medical condition (n = 29). Mean age of screened patients was 66 years (SD 9.8 years). Half of the screened patients suffered stroke (n = 36). The incidence of abdominal aortic aneurysm was 5.6% (n = 4). All found abdominal aortic aneurysms were small and did not require immediate surgical intervention. During a follow-up period of over 4 years, none of the aneurysms exhibited tendency for growth.

CONCLUSIONS

The male population with cerebrovascular disease is comorbid and frail. Only, moderate prevalence of abdominal aortic aneurysms can be found in this subpopulation.

Interleukin-6 Receptor Signaling and Abdominal Aortic Aneurysm Growth Rates

Supplemental Digital Content is available in the text.

Background:

The Asp358Ala variant (rs2228145; A>C) in the IL (interleukin)-6 receptor (IL6R) gene has been implicated in the development of abdominal aortic aneurysms (AAAs), but its effect on AAA growth over time is not known. We aimed to investigate the clinical association between the IL6R-Asp358Ala variant and AAA growth and to assess the effect of blocking the IL-6 signaling pathway in mouse models of aortic aneurysm rupture or dissection.

Methods:

Using data from 2863 participants with AAA from 9 prospective cohorts, age- and sex-adjusted mixed-effects linear regression models were used to estimate the association between the IL6R-Asp358Ala variant and annual change in AAA diameter (mm/y). In a series of complementary randomized trials in mice, the effect of blocking the IL-6 signaling pathways was assessed on plasma biomarkers, systolic blood pressure, aneurysm diameter, and time to aortic rupture and death.

Results:

After adjusting for age and sex, baseline aneurysm size was 0.55 mm (95% CI, 0.13–0.98 mm) smaller per copy of the minor allele [C] of the Asp358Ala variant. Change in AAA growth was −0.06 mm per year (−0.18 to 0.06) per copy of the minor allele; a result that was not statistically significant. Although all available worldwide data were used, the genetic analyses were not powered for an effect size as small as that observed. In 2 mouse models of AAA, selective blockage of the IL-6 trans-signaling pathway, but not combined blockage of both, the classical and trans-signaling pathways, was associated with improved survival (P<0.05).

Conclusions:

Our proof-of-principle data are compatible with the concept that IL-6 trans-signaling is relevant to AAA growth, encouraging larger-scale evaluation of this hypothesis.

Risk Factors for Abdominal Aortic Aneurysm in Population-Based Studies: A Systematic Review and Meta-Analysis

Abdominal aortic aneurysm (AAA) represents an important public health problem with a prevalence between 1.3% and 12.5%. Several population-based randomized trials have evaluated ultrasound screening for AAA providing evidence of a reduction in aneurysm-related mortality in the screened population. The aim of our study was to perform a systematic review and meta-analysis of the risk factors for AAA. We conducted a systematic review of observational studies and we performed a meta-analysis that evaluated the following risk factors: gender, smoking habits, hypertension, coronary artery disease and family history of AAA. Respect to a previous a meta-analysis we added the funnel plot to examine the effect sizes estimated from individual studies as measure of their precision; sensitivity analysis to check the stability of study findings and estimate how the overall effect size would be modified by removal of one study; cumulative analysis to evaluate the trend between studies in relation to publication year. Abdominal aortic aneurysm prevalence is higher in smokers and in males. On the other hand, while diabetes is a risk factor for many cardiovascular diseases, it is not a risk factor for AAA. In addition, it is important to underline that all countries, where AAA screening was set up, had high income level and the majority belong to Western Europe (United Kingdom, Sweden, Italy, Poland, Spain and Belgium). Abdominal aortic aneurysm screening is fundamental for public health. It could avoid deaths, ruptures, and emergency surgical interventions if abdominal aortic aneurysm was diagnosed early in the population target for screening.

Ultrasound Screening of Men with Coronary Artery Disease for Abdominal Aortic Aneurysms: A Prospective Dual Center Study

Background and Aims:

According to the heterogeneous results of previous studies, the prevalence of abdominal aortic aneurysm seems high among men with coronary artery disease. The associating risk factors for abdominal aortic aneurysm in this population require clarification. Our objective was to assess the prevalence of non-diagnosed abdominal aortic aneurysms in men with angiographically verified coronary artery disease and to document the associated co-morbidities and risk factors.

Material and Methods:

Altogether, 407 men with coronary artery disease were screened after invasive coronary angiography in two series at independent centers. Risk factor data were recorded and analyzed.

Results and Conclusion:

The mean age of the study cohort was 70.0 years (standard deviation: 11.0). The prevalence of previously undiagnosed abdominal aortic aneurysms in the whole screened population of 407 men was 6.1% (n = 25/407). In a multivariate analysis of the whole study population, the only significant risk factors for abdominal aortic aneurysm were age (odds ratio: 1.04, 95% confidence interval: 1.00–1.09) and history of smoking (odds ratio: 3.13, 95% confidence interval: 1.26–7.80). Non-smokers with abdominal aortic aneurysm were significantly older than smokers (mean age: 80.7 (standard deviation: 8.0) vs 68.0 (standard deviation: 11.1), p = 0.003), and age was a significant risk factor only among non-smokers (p = 0.011; p = 0.018 for interaction). Among smokers, the prevalence of abdominal aortic aneurysm was 8.8%, and 72% (n = 18/25) of all diagnosed abdominal aortic aneurysm patients were smokers. Prevalence of undiagnosed abdominal aortic aneurysms among patients with coronary artery disease is high, and history of smoking is the most significant risk factor for abdominal aortic aneurysm. Effectiveness of selective screening of abdominal aortic aneurysm in male patients with coronary artery disease warrants further studies.

The prevalence of abdominal aortic aneurysm is consistently high among patients with coronary artery disease

OBJECTIVE

Emerging evidence suggests high prevalence of abdominal aortic aneurysm (AAA) among patients with coronary disease. Accurate characterization of the association between coronary disease and AAA and of the actual prevalence of AAA among patients with angiography-verified coronary artery disease (CAD) is needed to evaluate the possible benefits of systematic screening for AAA.

METHODS

We searched for studies that reported the association between AAA and CAD or coronary heart disease (CHD; wider phenotype definition) in the general population (randomized controlled trials, prospective population cohorts) and those that reported the prevalence of AAA among patients with angiography-verified CAD through PubMed, Embase, and reference lists for the period between 1980 and 2014. Random-effects models were applied because of the high heterogeneity between included studies.

RESULTS

Among the general population, 23 studies reported the association between CHD and the occurrence of subclinical AAA (positive ultrasound screening; meta-analyzed odds ratio of 2.38 with 95% confidence interval [CI] of 1.78-3.19; P = 4.1 × 10(-9)). According to four prospective studies, CHD is a strong predictor of future AAA events (fatal and nonfatal; meta-analyzed hazard ratio of 3.49 with 95% CI of 2.56-4.76; P = 2.4 × 10(-15)). Altogether, 10 studies reported the prevalence of AAA among patients with angiography-verified CAD or undergoing coronary artery bypass grafting. Among men, meta-analyzed prevalence was 9.5% (95% CI, 7.6%-11.7%). Among men undergoing coronary artery bypass grafting or with three-vessel disease, the prevalence was 11.4% (95% CI, 9.1%-13.9%). Among women, the prevalence was low (0.35%).

CONCLUSIONS

The risk of subclinical AAA and future AAA events is high among patients with coronary disease. Screening for AAA among CAD patients by cardiologists would be easy and inexpensive, with possible benefits to survival and risk evaluation.

Population-Based Study of Incidence of Acute Abdominal Aortic Aneurysms With Projected Impact of Screening Strategy

BACKGROUND

Current abdominal aortic aneurysm (AAA) screening in men age 65 might have limited impact on overall AAA death rates if incidence is moving to older ages. Up-to-date population-based studies of age-specific incidence, risk factors, and outcome of acute AAA are needed to inform screening policy.

METHODS AND RESULTS

In a prospective, population-based study (Oxfordshire, UK, 2002-2014), the incidence and outcome of acute AAA events were determined. Based on population projections and current incidence trends, the impact of screening strategies in the UK was estimated. Over the 12-year period, 103 incident acute AAA events occurred in the study population of 92 728. Incidence/100 000/year was 55 in men ages 65 to 74 years, but increased to 112 at 75 to 85 and 298 at ≥85, with 66.0% of all events occurring at age ≥75 years. Incidence at ages 65 to 74 was highest in male smokers (274), with 96.4% of events in men <75 years occurring in ever-smokers. Extrapolating rates to the UK population, using trial evidence of screening efficacy, the current UK screening program would prevent 5.6% of aneurysm-related deaths (315 200 scans/year: 1426/death prevented, 121/year-of-life saved). Screening only male smokers age 65 and then all men at age 75 would prevent 21.1% of deaths (247 900 scans/year; 297/death prevented, 34/year-of-life saved). By 2030, 91.0% of deaths will occur at age ≥75, 61.6% at ≥85, and 28.6% in women.

CONCLUSIONS

Given that two thirds of acute AAA occurred at ≥75 years of age, screening older age groups should be considered. Screening nonsmokers at age 65 is likely to have very little impact on AAA event rates.

Age-specific incidence, risk factors and outcome of acute abdominal aortic aneurysms in a defined population

BACKGROUND

Contemporary population-based data on age-specific incidence and outcome from acute abdominal aortic aneurysm (AAA) events are needed to understand the impact of risk factor modification and demographic change, and to inform AAA screening policy.

METHODS

In a prospective population-based study (Oxfordshire, UK, 2002-2014), event rates, incidence, early case fatality and long-term outcome from all acute AAA events were determined, both overall and in relation to the four main risk factors: smoking, hypertension, male sex and age.

RESULTS

Over the 12-year interval, 103 incident acute AAA events occurred in the study population of 92,728 (men 72·8 per cent; 59·2 per cent 30-day case fatality rate). The incidence per 100,000 population per year was 55 in men aged 65-74 years, but increased to 112 at age 75-84 years and to 298 at age 85 years or above. Some 66·0 per cent of all events occurred in those aged 75 years or more. The incidence at 65-74 years was highest in male smokers (274 per 100,000 population per year); 27 (96 per cent) of 28 events in men aged less than 75 years occurred in ever-smokers. Mean(s.d.) age at event was lowest in current smokers (72·2(7·2) years), compared with that in ex-smokers (81·2(7·0) years) and never-smokers (83·3(7·9) years) (P < 0·001). Hypertension was the predominant risk factor in women (diagnosed in 93 per cent), with 20 (71 per cent) of all 28 events in women occurring in those aged 75 years or above with hypertension. The 30-day case fatality rate increased from 40 per cent at age below 75 years to 69 per cent at age 75 years or more (P = 0·008).

CONCLUSION

Two-thirds of acute AAA events occurred at age 75 years or above, and more than 25 per cent of events were in women. Taken with the strong associations with smoking and hypertension, these findings could have implications for AAA screening.

Baseline prevalence of abdominal aortic aneurysm, peripheral arterial disease and hypertension in men aged 65–74 years from a population screening study (VIVA trial)

Background

Abdominal aortic aneurysm (AAA) screening has been introduced into some health systems and could easily be supplemented with broader vascular screening. The aim of this study was to evaluate the screening set-up and investigate combined screening for AAA, peripheral arterial disease (PAD) and possible hypertension (HT), and detection rates.

Methods

This observational study was based on the intervention arm of a screening trial in 25 083 Danish men aged 65–74 years. A combined screening programme for AAA, PAD and HT was offered at local hospitals. Participants with positive test results were offered secondary prophylaxis and/or referred to their general practitioner. The programme set-up included decentralized screening by three mobile teams at 14 venues. Diagnostic criteria were: aortic diameter at least 30 mm for AAA, ankle : brachial pressure index below 0·9 or above 1·4 for PAD, and BP exceeding 160/100 mmHg for HT.

Results

Overall, 18 749 men (uptake 74·7 per cent) attended the screening. An AAA was diagnosed in 3·3 (95 per cent c.i. 3·0 to 3·6) per cent, PAD in 10·9 (10·5 to 11·4) per cent and HT in 10·5 (10·0 to 10·9) per cent. Lipid-lowering and/or antiplatelet treatment was initiated in 34·8 per cent of the participants.

Conclusion

Preventive actions were started in one-third of the attenders. The long-term effect of this on morbidity and mortality is an important part of future analysis. The trial confirms that the prevalence of AAA in Denmark has decreased only slightly in the past decade, from 4·0 to 3·3 per cent, in contrast to other nations.

Ruptured abdominal aortic aneurysms: decreasing incidence may reduce the impact of a Scottish screening programme

Objectives

The aim of this study was to determine whether there has been a change in annual ruptured abdominal aortic aneurysm admissions and elective abdominal aortic aneurysm repairs in a tertiary vascular surgery department.

Methods

All patients admitted with ruptured abdominal aortic aneurysm from 1987 to 2009 and all undergoing elective abdominal aortic aneurysm repair from 1995 to 2009 were identified from the local surgical audit database. Annual ruptured abdominal aortic aneurysm admissions were calculated and compared in the first and second halves of the study period.

Results

During a 23-year period, 888 patients (male 728, female 158, gender was not documented for two patients) were identified with a ruptured abdominal aortic aneurysm. The annual number of admissions remained relatively constant from 1987 to 1997, with a mean of 44 (95% CI 39.91–48.09). There was a significant decrease to a mean of 33.67 per annum (95% CI 28.53–38.8) in the period 1998–2009, p = 0.006. The mean mortality was 39.8% and showed no significant decrease. There was no increase in the number of elective abdominal aortic aneurysm repairs during the study period.

Conclusions

This study suggests that the incidence of ruptured abdominal aortic aneurysms is decreasing, mirroring the trend seen in other cardiovascular disease. As such, further analysis as to the cost-effectiveness of a Scottish screening programme is merited.