Screening for abdominal aortic aneurysms and associated risk factors in a general population

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.

Epidemiology of abdominal aortic aneurysms

Abdominal aortic aneurysm (AAA) disease remains a major source of morbidity in developed countries and can progress to life-threatening rupture if left untreated, with exceedingly high mortality. The goal of AAA management is to identify and electively repair AAAs before rupture. AAA disease burden and outcomes have improved over time with declining tobacco use and advancements in care across patients' disease course. The introduction of endovascular AAA repair, in particular, has allowed for elective AAA repair in patients previously considered too high risk for open surgery and has contributed to lower rates of AAA rupture over time. However, these improved outcomes are not universally experienced, and disparities continue to exist in the detection, treatment, and outcomes of AAA by sex, race, and ethnicity. Mitigating these disparities requires enhanced, focused efforts at preventing disease, promoting health, and delivering appropriate care among an increasingly diverse patient population.

Association of simple renal cysts and chronic kidney disease with large abdominal aortic aneurysm

Background

Abdominal aortic aneurysms (AAA) primarily affect men over 65 years old who often have many other diseases, with similar risk factors and pathobiological mechanisms to AAA. The aim of this study was to assess the prevalence of simple renal cysts (SRC), chronic kidney disease (CKD), and other kidney diseases (e.g. nephrolithiasis) among patients presenting with AAA.

Methods

Two groups of patients (97 AAA and 100 controls), with and without AAA, from the Surgical Clinic Charité, Berlin, Germany, were selected for the study. The control group consisted of patients who were evaluated for a kidney donation (n = 14) and patients who were evaluated for an early detection of a melanoma recurrence (n = 86). The AAA and control groups were matched for age and sex. Medical records were analyzed and computed tomography scans were reviewed for the presence of SRC and nephrolithiasis.

Results

SRC (74% vs. 57%; p<0.016) and CKD (30% vs. 8%; p<0.001) were both more common among AAA than control group patients. On multivariate analysis, CKD, but not SRC, showed a strong association with AAA.

Conclusions

Knowledge about pathobiological mechanisms and association between CKD and AAA could provide better diagnostic and therapeutic approaches for these patients.

Evaluating the prevalence of abdominal aortic aneurysms in the United States through a national screening database

OBJECTIVE

The U.S. Preventative Services Task Force guidelines for abdominal aortic aneurysm (AAA) screening are based mainly on studies of older Caucasian males from non-U.S.

POPULATIONS

This study was designed to analyze the findings of a large, all-inclusive AAA screening program in the United States.

METHODS

Screening events were held nationally by a U.S. nonprofit organization between 2001 and 2017. AAA screening was offered regardless of risk profile. Participants filled out a demographics form with known comorbidities. Significant risk factors were determined using logistic regression with backward stepwise variable selection. Odds ratios (OR) are reported with 95% confidence intervals (CIs).

RESULTS

A total of 9457 screened participants (47% male) were analyzed. The mean age was 67 ± 9 years with 40.8% between 65 and 75 years old. Most participants were Caucasian (83.4%), followed by African American (13.1%). Screened risk factors included hypertension (58.1%), hyperlipidemia (54.9%), smoking (52.0%), cardiac disease (29.2%), diabetes mellitus (18.4%), a family history of AAA (22.4%) or brain aneurysms (8.6%), and body mass index (26.9 ± 5.28). Overall, 267 participants (2.82%) were found to have an AAA (>3 cm). Those ages 65 to 75 had a prevalence of 2.98%. In a fully adjusted, multivariate logistic regression, there was an increased risk of AAA in males (OR, 3.24; 95% CI, 2.39-4.40), current smokers (OR, 3.28; 95% CI, 2.36-4.54), previous smokers (OR, 1.86; 95% CI, 1.41-2.47), cardiac disease (OR, 1.30; 95% CI, 1.01-1.68), family history of AAA (OR, 1.60; 95% CI, 1.20-2.14), and advancing age (P < .0001). Female ever smokers 65 to 75 years old had a prevalence of 1.7%. Male smokers 45 to 54 and 55 to 64 years old had a prevalence of 3.37% and 4.43%, respectively. There was an increased risk of AAA in females with morbid obesity (OR, 5.54; 95% CI, 1.34-22.83 in never smokers and OR, 5.61; 95% CI, 1.04-30.15 in smokers), female smokers with hypertension (OR, 3.22; 95% CI, 1.21-8.58), males with cardiac disease (OR, 2.06; 95% CI, 1.08-3.90 in never smokers and OR, 1.48; 95% CI, 1.05-2.09), male smokers with a family history of AAA (OR, 1.69; 95% CI, 1.61-2.46), and current smokers (OR, 6.33; 95% CI, 2.62-15.24 for females and OR, 2.50; 95% CI, 1.70-3.65 for males).

CONCLUSIONS

This study shows that there remain high-risk groups outside the current guidelines that would likely benefit from AAA screening. Risk factors for AAA include male gender, smoking, cardiac disease, family history of AAA, and advancing age. The most significant risk factor is current smoking status.

Matrix Metalloproteinase in Abdominal Aortic Aneurysm and Aortic Dissection

Abdominal Aortic Aneurysm (AAA) affects 4–5% of men over 65, and Aortic Dissection (AD) is a life-threatening aortic pathology associated with high morbidity and mortality. Initiators of AAA and AD include smoking and arterial hypertension, whilst key pathophysiological features of AAA and AD include chronic inflammation, hypoxia, and large modifications to the extra cellular matrix (ECM). As it stands, only surgical methods are available for preventing aortic rupture in patients, which often presents difficulties for recovery. No pharmacological treatment is available, as such researchers are attempting to understand the cellular and molecular pathophysiology of AAA and AD. Upregulation of matrix metalloproteinase (MMPs), particularly MMP-2 and MMP-9, has been identified as a key event occurring during aneurysmal growth. As such, several animal models of AAA and AD have been used to investigate the therapeutic potential of suppressing MMP-2 and MMP-9 activity as well as modulating the activity of other MMPs, and TIMPs involved in the pathology. Whilst several studies have offered promising results, targeted delivery of MMP inhibition still needs to be developed in order to avoid surgery in high risk patients.

Blood pressure, hypertension and the risk of abdominal aortic aneurysms: a systematic review and meta-analysis of cohort studies

Abdominal aortic aneurysms (AAA) are fatal in 80% of the cases when ruptured. Hypertension has been considered a potential risk factor for AAA; but the findings from prospective cohort studies have not been entirely consistent, nor have they been summarised in a comprehensive meta-analysis. Our aim was to conduct a systematic review and meta-analysis of cohort studies of the association between blood pressure, hypertension and AAA to clarify the strength and shape of these associations. We searched PubMed and Embase databases for relevant cohort studies up to April 30th, 2018. Random-effects models were used to calculate summary relative risks (RRs) and 95% confidence intervals (CIs). The meta-analysis included 21 cohort studies (20 publications) with data on 28,162 cases and 5,440,588 participants. The findings indicate that the RR of AAA in hypertensive patients is 1.66 times (95% CI: 1.49–1.85, I² = 79.3%, n = 13) that of non-hypertensive patients. In addition, there was a 14% (95% CI: 6–23%, I² = 30.5%, n = 6) and a 28% (95% CI: 12–46%, I² = 80.1%, n = 6) increase in the RR of AAA for every 20 mmHg and 10 mmHg increase in systolic blood pressure (SBP) and diastolic blood pressure (DBP), respectively. The analysis of DBP showed evidence of a strong and highly significant nonlinear dose–response relationship (p < 0.001) with a steeper association from 80 mmHg and above. This meta-analysis suggests that hypertension increases the risk of developing AAA by 66%. Further studies are needed to clarify the underlying mechanism explaining the much stronger association between DBP and AAA than for SBP.

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.

Screening for thoracic aortic pathology: Clinical practice in a single tertiary center

OBJECTIVE

The aim is to present current clinical practice of thoracic aorta screening in a tertiary referral center. We identified how often imaging techniques were used for screening and established the value of transthoracic echocardiography (TTE) in comparison with computed tomography (CT) to detect aortic dilation. We also investigated which additional abnormalities of the heart, aorta or smaller arteries were discovered.

DESIGN

All patients ≥15 years who visited our tertiary center in 2012-2016 for first thoracic aortic screening were retrospectively included. Diameters of the sinus of Valsalva (SoV) and maximum ascending aorta (AA) were compared between TTE and CT. The sensitivity and specificity of TTE to detect aortic dilation (≥40 mm) was assessed with CT as reference standard. Intracardiac abnormalities found with TTE and arterial abnormalities found with CT were identified.

RESULTS

In total 349 patients (155 men, age 41 ± 15 years, 10% genetic mutation) were included. Screening was performed with TTE only in 35% and with TTE and CT in 65%. Patients who underwent TTE only were younger, had less often hypertension and less often a family history of aortic pathology. Although there was a good correlation between TTE and CT, the diameters measured with TTE were typically lower (SoV -1.0, 95%CI -6.6 to 4.7 and AA -0.4, 95%CI -6.5 to 5.8). Sensitivity of TTE for detecting aortic dilation was 61% (SoV) and 57% (AA) and specificity was 96% (SoV) and 100% (AA). Valve abnormalities, ventricular dilation or reduced ventricular function was found with TTE in 26 patients (7%). In 47 patients (13%) ascending aortic dilation was diagnosed and in 10 patients (4%) relevant peripheral arterial abnormalities were identified using CT.

CONCLUSIONS

Most often patients received both TTE and CT (65%). Since TTE showed a low sensitivity to detect aortic dilation, CT imaging is advised at least once in patients referred for thoracic aortic screening.

Association between diabetes and prevalence and growth rate of abdominal aortic aneurysms: A meta-analysis

BACKGROUND

Although the prevalence of abdominal aortic aneurysm (AAA) was lower in diabetes, the relationship between diabetes and AAA prevalence remains unclear. In this meta-analysis, we sought to clarify the effect of diabetes on prevalence and growth rate (GR) of AAA.

METHODS

We searched PubMed, Web of Science, Scopus and Cochrane databases. Articles reporting the AAA prevalence in diabetic patients and diabetic effects in GR of AAA were included.

RESULTS

Forty-nine studies on AAA prevalence in diabetics and thirteen studies on effect of diabetes in GR of AAA were included for meta-analysis. A strongly negative association was found between diabetes and AAA prevalence in population based screening (odds ratio [OR]adjusted: 0.66; 95% confidence interval [CI]: 0.58-0.75) and prospective studies (ORadjusted: 0.52; 95% CI: 0.43-0.63), but not in case-control studies (ORadjusted: 0.48; 95% CI: 0.20-1.15). Similar association was found in North American (ORadjusted: 0.62; 95% CI 0.54-0.71) and European (ORadjusted: 0.45; 95% CI 0.33-0.62) studies. The strongly negative association remained consistent after stratification by time of data collection (up to -1995 [ORadjusted: 0.65; 95% CI: 0.53-0.80], 1996-2005 [ORadjusted: 0.61; 95% CI: 0.47-0.78], 2006 and beyond- [ORadjusted: 0.67; 95% CI: 0.53-0.85], and data collection time >10years [ORadjusted: OR: 0.44; 95% CI 0.34-0.58]). The annual mean diabetic effect on AAA GR was -0.60mm/y (95% CI: -0.76 - -0.43).

CONCLUSION

Diabetes was strongly and negatively associated with AAA prevalence regardless of study type, geography and time of data collection, as well as negative impact of diabetes on GR of AAA.

Association of diabetes mellitus with presence, expansion, and rupture of abdominal aortic aneurysm: "Curiouser and curiouser!" cried ALICE

Both coronary artery and peripheral artery disease are representative atherosclerotic diseases that are positively associated with presence of abdominal aortic aneurysm (AAA). Diabetes mellitus, which is one of major risk factors of coronary artery and peripheral artery diseases, however, has been curiously suggested to be negatively associated with AAA, despite the positive associations of coronary artery and peripheral artery diseases with presence of AAA. In the present article, we overviewed epidemiologic evidence (meta-analyses) regarding the associations of diabetes mellitus with presence, expansion, and rupture of AAA through a systematic literature search. Our exhaustive search identified seven meta-analyses. Main results of almost all meta-analyses (except for the two earliest ones) apparently found that diabetes mellitus is negatively associated with presence, expansion, and rupture of AAA.

Chronic obstructive pulmonary disease effect on the prevalence and postoperative outcome of abdominal aortic aneurysms: A meta-analysis

Epidemiologic evidence suggested chronic obstructive pulmonary disease (COPD) might increase risk for abdominal aortic aneurysm (AAA). However, the association between COPD and AAA remains inconclusive. We searched PubMed and Cochrane databases until June 2015. Forty-eight articles were included for meta-analysis. COPD was found to be positively associated with AAA, regardless of study design and smoking status. AAA mortality is higher among COPD patients compared with non-COPD patients (postoperative [adjusted OR 2.11; 95% CI 1.33–3.34]; long-term [adjusted OR 1.70; 95% CI 1.37–2.12]). But the association between postoperative mortality and COPD was not found to be significant in patients underwent endovascular aneurysm repair (mixed OR 2.53; 95% CI 0.70–9.18). Rupture AAA may increase the postoperative mortality in COPD patients (rupture [adjusted OR 4.75; 95% CI 2.07–10.89]; non-rupture [adjusted OR 1.97; 95% CI 1.11–3.49]). The AAA postoperative morbidity was found to be positively associated with COPD (adjusted OR 1.59; 95% CI 1.14–2.21). Increased COPD severity may increase the long-term mortality (medical versus oxygen dependent: [OR 1.26; 95% CI 1.07–1.49] versus [OR 2.79; 95% CI 2.24–3.49]). In conclusion, COPD may increase the risk of AAA, morbidity and mortality of AAA patients underwent endovascular aortic repair.

Asthma Associates With Human Abdominal Aortic Aneurysm and Rupture

OBJECTIVE

Both asthma and abdominal aortic aneurysms (AAA) involve inflammation. It remains unknown whether these diseases interact.

APPROACH AND RESULTS

Databases analyzed included Danish National Registry of Patients, a population-based nationwide case-control study included all patients with ruptured AAA and age- and sex-matched AAA controls without rupture in Denmark from 1996 to 2012; Viborg vascular trial, subgroup study of participants from the population-based randomized Viborg vascular screening trial. Patients with asthma were categorized by hospital diagnosis, bronchodilator use, and the recorded use of other anti-asthma prescription medications. Logistic regression models were fitted to determine whether asthma associated with the risk of ruptured AAA in Danish National Registry of Patients and an independent risk of having an AAA at screening in the Viborg vascular trial. From the Danish National Registry of Patients study, asthma diagnosed <1 year or 6 months before the index date increased the risk of AAA rupture before (odds ratio [OR]=1.60-2.12) and after (OR=1.51-2.06) adjusting for AAA comorbidities. Use of bronchodilators elevated the risk of AAA rupture from ever use to within 90 days from the index date, before (OR=1.10-1.37) and after (OR=1.10-1.31) adjustment. Patients prescribed anti-asthma drugs also showed an increased risk of rupture before (OR=1.12-1.79) and after (OR=1.09-1.48) the same adjustment. In Viborg vascular trial, anti-asthmatic medication use associated with increased risk of AAA before (OR=1.45) or after adjustment for smoking (OR=1.45) or other risk factors (OR=1.46).

CONCLUSIONS

Recent active asthma increased risk of AAA and ruptured AAA. These findings document and furnish novel links between airway disease and AAA, 2 common diseases that share inflammatory aspects.

Meta-Analysis of Abdominal Aortic Aneurysm in Patients With Coronary Artery Disease

The high coronary artery disease (CAD) prevalence in patients with abdominal aortic aneurysm (AAA) is well known. However, the inverse relation has been little explored. We present, based on a systematic review and meta-analysis of the published evidence, a critical appraisal of the issue of AAA prevalence and also AAA predictive risk factors in patients with CAD, comparing it with AAA prevalence in subjects without CAD. A total of 22 studies involving 13,388 patients with CAD met the inclusion criteria. Overall, AAA prevalence in patients with CAD was 8.4% (95% confidence interval [CI] 6.9 to 10.3), significantly higher than in subjects without CAD (odds ratio [OR] 2.42, 95% CI 2.08 to 2.81). Pooled analysis revealed that smoking, arterial hypertension, and concomitant carotid artery stenosis were significantly associated with AAA in patients with CAD (OR 1.72, 95% CI 1.14 to 2.61; OR 1.57, 95% CI 1.06 to 2.35; OR 2.14, 95% CI 1.20 to 3.79, respectively). In patients with CAD, AAA prevalence tended to be higher with concomitant peripheral artery disease (OR 2.66, 95% CI 0.82 to 8.61, p = 0.08). In conclusion, AAA prevalence was significantly higher in patients with CAD versus subjects without CAD.

Epidemiology, Clinical Features, and Prescribing Patterns of Aortic Aneurysm in Asian Population From 2005 to 2011

Aortic aneurysm (AA) is a leading cause of death in Asia and the world. The prevalence in Western countries is around 1.3% to 8%. However, it is still unclear about the incidence, prevalence, and mortality of AA in Asian population. The aim of this study is to investigate the epidemiology of AA for all subtypes in Taiwan, and describe the clinical features and prescribing patterns for AA population.A population-based study was conducted using information from National Health Insurance Research Database (NHIRD) in Taiwan. Patients who were diagnosed with AA and also received computed tomography (CT) were included in this study. Incidence, prevalence, and mortality were calculated in each year during 2005 to 2011. Prevalent comorbidities and prescribing patterns were both evaluated among study population.The average annual incidence of AA in Taiwan was 7.35 per 100,000 population, and the prevalence was 29.04 per 100,000 population. It showed an increased trend of incidence from 2005 to 2011, so as prevalence and mortality. The incidence was associated with age and sex difference. It was much higher in those older than 65 years, especially for male. Hypertension, coronary artery disease (CAD), and chronic obstructive pulmonary disease (COPD) were prevalent comorbidities. Eighty-eight percentages of patients were prescribed antihypertensive agents in acute phase, where 61.4% of calcium channel blocker (CCB) was the most one.Our study found that incidence of AA was lower in Taiwan than in other countries. Nevertheless, it showed an increased trend of AA disease for incidence, prevalence, and also mortality during 2005 to 2011.

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.

Prevalence and trends of the abdominal aortic aneurysms epidemic in general population--a meta-analysis

OBJECTIVE

To conduct a meta-analysis assessing the prevalence and trends of the abdominal aortic aneurysms (AAA) epidemic in general population.

METHOD

Studies that reported prevalence rates of AAA from the general population were identified through MEDLINE, EMBASE, Web of Science, and reference lists for the period between 1988 and 2013. Studies were included if they reported prevalence rates of AAA in general population from the community. In stratified analyses possible sources of bias, including areas difference, age, gender and diameter of aneurysms were examined. Publication bias was assessed with Egger's test method.

RESULTS

56 studies were identified. The overall pooled prevalence of AAA was 4.8% (4.3%, 5.3%). Stratified analyses showed the following results, areas difference: America 2.2% (2.2%, 2.2%), Europe 2.5% (2.4%, 2.5%), Australia 6.7% (6.5%, 7.0%), Asia 0.5% (0.3%, 0.7%); gender difference: male 6.0% (5.3%, 6.7%), female 1.6% (1.2%, 1.9%); age difference: 55-64years 1.3% (1.2%, 1.5%), 65-74 years 2.8% (2.7%, 2.9%), 75-84 years1.2%(1.1%, 1.3%), ≥85years0.6% (0.4%, 0.7%); aortic diameters difference: 30-39 mm, 3.3% (2.8%, 3.9%), 40-49 mm,0.7% (0.4%,1.0%), ≥50 mm, 0.4% (0.3%, 0.5%). The prevalence of AAA has decreased in Europe from 1988 to 2013. Hypertension, smoking, coronary artery disease, dyslipidemia, respiratory disease, cerebrovascular disease, claudication and renal insufficiency were risk factors for AAA in Europe.

CONCLUSION

AAA is common in general population. The prevalence of AAA is higher in Australia than America and Europe. The pooled prevalence in western countries is higher than the Asia. Future research requires a larger database on the epidemiology of AAA in general population.

Incidental abdominal aneurysms: a retrospective study of 13,115 patients who underwent a computed tomography scan

We evaluated the frequency and outcomes of abdominal aortic aneurysm (AAA) in Qatar. Data were collected retrospectively between 2004 and 2008 for all adult patients who underwent abdominal computed tomographic scanning for any reason. Patients with AAA were followed up for 3 years for aneurysmal rupture and mortality. Of the 13,115 patients screened, 61 (0.5%) patients had abdominal aneurysms. Most (82%) patients with AAA were male with mean age of 67 ± 12 years. The incidence of AAA substantially increased with age. Cardiovascular risk factors were prevalent among patients with AAA. The main location of AAA was infrarenal (67%), followed by thoracoabdominal (23%). The mean AAA diameter was 5.3 ± 2.5 cm. The rate of AAA rupture was 8% with a mortality rate of 60%; 80% of these were infrarenal, and 80% of them had a diameter of ≥5.5 cm. Overall mortality was 33%. This large study addressed the impact of screening for AAA in a population with high cardiovascular burden.

Current prevalence of abdominal aortic aneurysm in 70-year-old women

BACKGROUND

Screening elderly men for abdominal aortic aneurysm (AAA) to reduce mortality from rupture is evidence-based. For women epidemiological data on AAA are scarce, and the evidence for screening is insufficient. The aim of this population-based study was to determine the current prevalence of AAA and risk factors among 70-year-old women.

METHODS

All 70-year-old women identified through the National Population Registry in the two neighbouring counties of Uppsala and Dalarna were invited to a free ultrasound examination of the abdominal aorta. An AAA was defined as a maximum infrarenal aortic diameter of at least 30 mm.

RESULTS

Of 6925 women invited, 5140 (74·2 per cent) accepted the invitation to be screened. Among these, 19 AAAs were detected (0·4 (95 per cent confidence interval (c.i.) 0·2 to 0·5) per cent). In the invited cohort 12 women (0·2 (0·1 to 0·3) per cent) had undergone previous AAA repair (11) or had a known AAA under surveillance (1). Thus, the total prevalence was estimated at 0·5 (0·4 to 0·7) per cent. Smoking was strongly associated with AAA; 18 (95 per cent) of 19 women with a screen-detected AAA had a history of smoking compared with 44·2 per cent of those with a normal aorta (odds ratio 20·29, 95 per cent c.i. 2·70 to 152·65). The prevalence of AAA was 0·03 (0 to 0·1) per cent among never smokers, 0·4 (0·2 to 0·8) per cent among former smokers and 2·1 (1·0 to 3·7) per cent among current smokers.

CONCLUSION

Screening 70-year-old women who do not smoke is likely to be futile, thus ruling out population screening of women for AAA.

Use of a Web-based clinical decision support system to improve abdominal aortic aneurysm screening in a primary care practice

RATIONALE, AIMS AND OBJECTIVES

The United States Preventive Services Task Force recommends a one-time screening for abdominal aortic aneurysm (AAA) with ultrasonography for men aged 65 to 75 years who have ever smoked. However, despite a mortality rate of up to 80% for ruptured AAAs, providers order the screening for a minority of patients. We sought to determine the effect of a Web-based point-of-care clinical decision support system on AAA screening rates in a primary care practice.

METHODS

We conducted a retrospective review of medical records of male patients aged 65 to 75 years who were seen at any of our practice sites in 2007 and 2008, before and after implementation of the clinical decision support system.

RESULTS

Overall screening rates were 31.36% in 2007 and 44.09% in 2008 (P-value: <0.001). Of patients who had not had AAA screening prior to the visit, 3.22% completed the screening after the visit in 2007, compared with 18.24% in 2008 when the clinical support system was implemented, 5.36 times improvement (P-value: <0.001).

CONCLUSIONS

A Web-based clinical decision support for primary care physicians significantly improved delivery of AAA screening of eligible patients. Carefully developed clinical decision support systems can optimize care delivery, ensuring that important preventive services are delivered to eligible patients.

Transient exposure of neonatal female mice to testosterone abrogates the sexual dimorphism of abdominal aortic aneurysms

RATIONALE

Abdominal aortic aneurysms (AAAs) exhibit marked sexual dimorphism with higher prevalence in men. Similarly, AAAs induced by angiotensin II (AngII) infusion into mice exhibit a higher prevalence in males. Testosterone promotes AAA pathology in adult male mice through regulation of angiotensin type 1A receptors (AT1aR) in abdominal aortas. However, mechanisms for sexual dimorphism of regional aortic angiotensin receptor expression and AAA formation are unknown.

OBJECTIVE

To define the role of developmental testosterone exposures in sexual dimorphism of AAAs, we determined if exposure of neonatal female mice to testosterone confers adult susceptibility to AngII-induced AAAs.

METHODS AND RESULTS

One-day-old female hypercholesterolemic mice were administered a single dose of either vehicle or testosterone. Neonatal testosterone administration increased abdominal aortic AT1aR mRNA abundance and promoted a striking increase in AngII-induced AAAs in adult females exhibiting low serum testosterone concentrations. AngII-induced atherosclerosis and ascending aortic aneurysms were also increased by testosterone administration to neonatal females. In contrast, neonatal testosterone administration in males had no effect on AngII-induced vascular pathologies. Deficiency of AT1aR in smooth muscle cells reduced effects of neonatal testosterone to promote AAAs in adult females but did not alter atherosclerosis or ascending aortic aneurysms. Testosterone increased AT1aR mRNA abundance and hydrogen peroxide generation in cultured abdominal aortic SMCs. Increased AT1aR mRNA abundance was maintained during progressive passaging of female smooth muscle cells.

CONCLUSIONS

These data reveal an unrecognized role of transient sex hormone exposures during neonatal development as long-lasting mediators of regional aortic AT1aR expression and sexual dimorphism of AAAs.

Statin therapy reduces growth of abdominal aortic aneurysms

BACKGROUND

The aim of this study was to evaluate the influence of statins on the growth of small abdominal aortic aneurysms (AAAs).

METHODS

We retrospectively examined AAA diameter in 211 patients who had undergone serial imaging surveillance.

RESULTS

Patients treated with and without statins were similar regarding age, initial aneurysm size, diagnosis of diabetes and hypertension, and smoking history. Patients receiving statins had a decreased aneurysm growth rate compared with those patients not receiving statins (0.9 mm/y [interquartile range, -1.0 to +1.0] vs 3.2 mm/y [interquartile range, 2.0-4.9], P < 0.0001). This difference in the rate of growth was maintained after adjusting for potential confounding factors.

CONCLUSIONS

To date, this is the one of the largest retrospective studies demonstrating an association between statin use and decreased growth rate of AAA.

Patients with Abdominal Aortic Aneurysm and Chronic Obstructive Pulmonary Disease Have Improved Outcomes with Endovascular Aneurysm Repair Compared with Open Repair

The purpose of our study was to evaluate outcomes in abdominal aortic aneurysm (AAA) patients with chronic obstructive pulmonary disease (COPD) undergoing open or endovascular abdominal aortic aneurysm repair (EVAR). We retrospectively examined the records of consecutive patients with AAA and COPD who underwent either open repair or EVAR between 2001 and 2008. In-hospital and follow-up outcomes were compared between open repair and EVAR using SPSS (SPSS Inc, Chicago, IL). Sixty-nine patients were included for analysis (mean age 71 ± 1.0 years; 93% [ n = 64] male). Open surgery was performed in 63% ( n = 43). In-hospital mortality was 4%. All-cause mortality did not differ significantly between the open repair and EVAR groups during 3 years of follow-up ( p = .491). In-hospital death and major complications occurred in 30% ( n = 13) after open repair compared with 12% ( n = 3) after EVAR ( p = .075). Pneumonia occurred in 19% ( n = 8) after open repair and in 0% after EVAR ( p = .019); pneumonia was associated with increased mortality during the first year after AAA repair (log-rank test p = .003). Hospital length of stay was increased in the open repair group compared with the EVAR group (16 vs 5 days, p < .001), as was intensive care unit length of stay (11 vs 2 days, p < .001) and need for ventilation (61% vs 12%, p < .001). Patients with COPD and anatomically suitable AAAs should be preferentially offered EVAR.

Diabetes and the abdominal aortic aneurysm

OBJECTIVE

The aim of this review is to delineate the association between abdominal aortic aneurysms (AAAs) and diabetes mellitus. Mechanisms for the underlying association are then discussed.

METHODS

A systematic review of the English-language literature using PubMed, EMBASE and Cochrane databases was undertaken up to September 2009. Studies reporting appropriate prevalence data were identified and a meta-analysis performed.

RESULTS

Eleven studies were identified. The prevalence of diabetes mellitus in studied patients with AAA ranged from 6% to 14%. The prevalence of diabetes in control patients without AAA ranged from 17% to 36%. Pooled analysis suggested a reduced rate of diabetes amongst people with AAA compared to those without (OR 0.65, 0.60-0.70, p<0.001).

CONCLUSIONS

Studies so far suggest a protective role for diabetes on the development of AAA. Further research is required to demarcate the underlying mechanisms for this possible association.

Apoptotic cell death and rupture of abdominal aortic aneurysm

The abdominal aortic aneurysm (AAA) development and expansion is characterized by an extracellular matrix degradation and widespread inflammation. In contrast, the processes that characterize the AAA rupture are not completely understood. The results obtained in animal and clinical studies have shown the importance of inflammation, proteolysis, and antioxidant mechanisms in the aortic degeneration and formation of AAA. We hypothesize that the rupture of the AAA could have a similar pathway like an atherosclerotic plaque rupture, and in both the cases the apoptotic cell death of smooth muscle cells could play a significant role. If the apoptotic cell death significantly contributes to the expansion and rupture of aneurysm, the hypothesis is that aggressive medical antiapoptotic treatment with high doses of appropriate drugs could decrease the apoptotic index of smooth muscle cells, reduce the aneurysm expansion and prevent rupture.

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.

Prevalence of risk factors, coronary and systemic atherosclerosis in abdominal aortic aneurysm: comparison with high cardiovascular risk population

Background:

Abdominal aortic aneurysm (AAA) is considered a manifestation of atherosclerosis, however there are epidemiologic, biochemical, and structural differences between occlusive atherosclerosis and AAA. The pathogenesis of AAA involves several factors, first of all destruction of collagen and elastin in the aortic wall. Classical risk factors may influence the evolution and development of AAA, though no consistent association has been found. Aims of the study were to evaluate associations between risk factors and to establish the prevalence of carotid, peripheral vascular and coronary atherosclerosis in patients with AAA.

Methods:

We studied 98 patients with AAA (Group 1) awaiting surgery compared with high cardiovascular risk population having two or more risk factors (n = 82 Group 2). We evaluated traditional risk factors and we studied by eco-doppler and echocardiography the presence of carotid peripheral and coronaric atherosclerosis in two groups.

Results:

We found a higher incidence of AAA in males (p < 0.01). The prevalence of infrarenal AAA was significantly higher than suprarenal AAA (81 vs 17 p < 0.001). No differences in total cholesterol (199 ± 20 vs. 197 ± 25 mg/dl), low-density lipoprotein (142 ± 16 vs. 140 ± 18 mg/dl), triglycerides (138 ± 45 vs. 144 ± 56 mg/dl), glycemia (119 ± 15 vs. 122 ± 20 mg/dl), and fibrinogen (388 ± 154 vs. 362 ± 92 mg/dl) were found between groups. We demonstrated significant differences for cigarette smoking (p < 0.002), systolic and diastolic blood pressure (150 ± 15 vs. 143 ± 14 mmHg and 88 ± 6 vs. 85 ± 7 mmHg, p < 0.0001 and p < 0.05, respectively) and high sensititivity C reactive protein (2.8 ± 1.3 vs. 1.3 ± 0.7 mg/dl, p < 0.001). High-density lipoprotein (HDL) cholesterol levels were significant greater in Group 1 than Group 2 (p < 0.003). Subgroups of patients with AAA and luminal thrombus showed higher fibrinogen levels (564 ± 235 vs. 341 ± 83 mg/dl, p < 0.001) and lower HDL than in controls (46.6 ± 6.5 vs. 52.1 ± 7.8 mg/dl, p < 0.01). We did not find any difference in body mass index, or prevalence of coronary and peripheral atherosclerosis between groups. Conversely, we found higher prevalence of carotid atherosclerosis in Group 2 (9% vs. 25%, p < 0.004).

Conclusion:

Our AAA patients had fewer and different risk factors respect to patients with atherosclerosis. Only elevated blood pressure, C reactive protein, and smoking showed a significant association with AAA. Atherosclerosis in other arterial districts did not differ respect to subjects with high cardiovascular risk. Our results confirm the hypothesis that AAA and atherosclerosis are two different pathological entities with different risk profiles.

Are Statins an Option in the Management of Abdominal Aortic Aneurysms?

Medline was searched for studies investigating the perioperative and long-term results that derive from statin use in patients with abdominal aortic aneurysm and the clinical and experimental evidence dealing with aneurysm expansion. Data suggest that statins improve the perioperative and long-term outcomes of aneurysm operations and may also reduce expansion rates. International guidelines recommend the use of statins in these patients because abdominal aortic aneurysms are considered as a coronary heart disease equivalent. These guidelines do not appear to have been widely implemented. Preliminary results suggest that statins might play a role in the management of abdominal aortic aneurysms. Verification of these results in large-scale trials may hold implications for a more comprehensive approach of patients with abdominal aortic aneurysms as well as population-wide aneurysm screening programs. Irrespective of the role of statins on aneurysm expansion rates, it is important to ensure that all abdominal aortic aneurysm patients receive statin therapy to improve perioperative and long-term morbidity and mortality.

Ultrasound screening for abdominal aortic aneurysm in medicare beneficiaries

Ultrasound screening for abdominal aortic aneurysm (AAA) has been shown to be beneficial and cost-effective for men aged 65-74. However, most screening studies have been conducted in Europe and Australia, where attendance for screening was higher than the single large U.S. study involving only veterans. The prevalence of AAA in the U.S. general population is not well defined, nor is the best method of recruitment for screening. Letters of invitation for a free screening ultrasound for AAA were sent to 30,000 randomly selected Medicare beneficiaries from the hospital referral region of three university-affiliated hospitals without restriction by age, gender, or comorbidity. Attendance for screening was calculated by age, gender, and travel distance to the screening center. Telephone calls to a random sample of nonresponders were made to determine the reason for failure to attend. Prevalence of AAA by ultrasound and known risk factors for AAA (e.g., age, gender, smoking status) were determined. The attendance rate was 7% (2,005). Attendance was greater with male gender (p < 0.01), younger age (p < 0.05), and decreased travel distance to the screening center (p < 0.05). The primary reasons for failure to attend included incorrect address or vital status, poor health, and lack of interest. Prevalence of previously undetected AAA was 2.8% in men and 0.2% in women. AAA was predicted by smoking status and male gender (p < 0.01 for each). Unselected invitation of Medicare beneficiaries for ultrasound screening for AAA results in a low attendance and low yield of AAA. The prevalence estimates from this study may not reflect the entire Medicare population given the low attendance and may reflect the healthy habits of those most interested in screening. Patients should be selected for screening based on their suitability for repair if an AAA is found as well as their risk factors for AAA. The best method of recruitment for screening of those most at risk for AAA in the United States remains to be determined.

Abdominal aortic aneurysm in women: Prevalence, risk factors, and implications for screening

OBJECTIVE

Accurate data regarding the prevalence and associated risk factors for aneurysmal disease is essential when determining the appropriateness of screening for abdominal aortic aneurysms (AAA). Although women are poorly represented in most large studies of AAA prevalence, the US Preventative Services Task Force recently recommended against primary screening for AAA in women. The purpose of this analysis was to define the prevalence and risk factors associated with the development of AAA in women.

METHODS

A free duplex ultrasound screening was offered to men and women with cardiovascular risk factors or a family history of AAA. Patients were recruited through advertising at local screening centers and screenings were performed between 2004 and 2006. Demographic information and cardiovascular and aneurysmal disease risk factors were obtained for each patient through a questionnaire. A total of 17,540 subjects were screened for AAA, including 10,012 women (mean age 69.6 years) and 7528 men (mean age 70.0 years). Univariate and multivariable logistic regression analysis was performed on the subset of women that were screened to determine risk factors for and prevalence of AAA.

RESULTS

Seventy-four aneurysms were detected in women (including four aneurysms >5 cm diameter and 70 aneurysms 3 to 5 cm diameter) while 291 were detected in men, resulting in prevalence rates of 0.7% and 3.9%, respectively. Increasing age (odds ratio [OR]= 4.57, 95% confidence interval [CI] 1.98 to 10.54, P < .0001), history of tobacco use (OR = 3.29, 95% CI 1.86 to 5.80, P < .0001), and cardiovascular disease (OR= 3.57, 95% CI 2.19 to 5.84, P < .0001) were independently associated with AAA in women on univariate and multivariable analysis. Women with multiple atherosclerotic risk factors were more commonly found to have AAAs and had a prevalence rate of AAA as high as 6.4%.

CONCLUSION

Although the medical literature suggests a low prevalence rate of AAA in women in the general population, specific risk factors are associated with the development of AAA, and subgroups of women can be identified that are at a substantially increased risk of aneurysmal disease. In particular, elevated rates of AAA were found among women of advanced age (> or =65 years) with a history of smoking or heart disease. These data support the notion that women with such risk factors should be considered for AAA screening.

Traditional and novel risk factors for clinically diagnosed abdominal aortic aneurysm: the Kaiser multiphasic health checkup cohort study

BACKGROUND

Identification of risk factors for and early diagnosis of clinically significant abdominal aortic aneurysm (AAA) before rupture is vital to optimize outcomes in these patients. Our aim was to examine traditional and three novel potential risk factors (abdominal obesity, white blood cell count, and kidney function) for abdominal aortic aneurysm (AAA, comprising discharge diagnosis or surgical repair) in a large multiethnic population.

METHODS

Cohort study (N =104,813) conducted at an integrated health care delivery system in northern California.

RESULTS

After a median of 13 years, 605 AAA events (490 in men and 115 in women; 91 [15%] fatal) were observed. In multivariable analysis, factors significantly associated with risk of clinically detected AAA included male gender, older age, black race (inversely), low educational attainment, cigarette smoking (with dose-response relation), height, treated and untreated hypertension, high total serum cholesterol, elevated white blood cell count, known coronary artery disease, history of intermittent claudication, and reduced kidney function. A significant Asian race by gender interaction was found such that Asian race had a (borderline significant) protective association with AAA in men but not in women.

CONCLUSIONS

Our findings confirm that major atherosclerotic risk factors, except for diabetes and obesity, are also prospectively related to AAA and suggest that elevated white blood cell count and reduced kidney function may improve risk stratification for clinically relevant AAA.

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.

Informing the efficient use of health care and health care research resources - the case of screening for abdominal aortic aneurysm in Sweden

BACKGROUND

An analytical framework using Bayesian decision theory and value-of-information analysis has recently been advocated for the economic evaluation of health technologies. The purpose of this study was to apply this framework to screening for abdominal aortic aneurysm (AAA) in Sweden and to compare the conclusions from this study with the conclusions presented in an assessment performed by the Swedish Council of Technology Assessment (SBU).

METHODS

A probabilistic decision-analytical model was developed to establish the cost-effectiveness of a screening programme for AAA relative to current clinical practice and to calculate the value-of-information.

RESULTS

The cost per quality-adjusted life-year for screening was 9700 euro. The expected value of perfect information for the assessment of overall cost-effectiveness was low, suggesting little benefit in conducting further research. Expected value of perfect partial information indicated that rupture probabilities were associated with the highest uncertainty. By contrast, the SBU report concluded there was limited evidence of cost-effectiveness and proposed further research.

CONCLUSION

The investigated screening programme for AAA is likely to be cost-effective and conducting another clinical trial is unlikely to add much valuable information to this decision problem. These recommendations contrast with the vaguer recommendations from SBU that more evidence is required of costs-effectiveness.

Abdominal aortic aneurysm: pathogenesis and implications for management

Abdominal aortic aneurysm (AAA) affects approximately 5% of elderly men and is responsible for a significant number of deaths in Western Countries. At present surgery by open or endovascular means is the only widely used therapy for this condition. In this review we examine the risk factors, serum, and genetic associations of AAA. Epidemiology studies suggest that smoking cessation and control of cholesterol and blood pressure should reduce the number of patients developing AAA. Natural history studies suggest that smoking cessation should reduce the rate of progression of AAA. Clear level 1 evidence for drug treatments of AAA are presently lacking; however, animal and human in vitro studies suggest that medication targeted at reducing inflammation and proteolysis are most likely to be beneficial, with limited data to support the use of statins, Angiotensin II inhibitors, and macrolides. Work has commenced in understanding which patients, identified by clinical, serum, and genotype, are more at risk of AAA progression and thus should be selected out for aggressive treatment. Well designed large multicenter randomized controlled trials are required to examine the medical treatment of AAA.

Elective Versus Ruptured Abdominal Aortic Aneurysm Repair: A 1-Year Cost-Effectiveness Analysis

Abdominal aortic aneurysm (AAA) is a life-threatening condition with an overall mortality of 80%. It predominantly affects men 65-74 years of age and is caused by focal distension of the main blood vessel in the abdomen. Most patients go undetected until their aneurysm ruptures. Controversy surrounds the most appropriate form of screening for AAA. Currently, screening is only carried out selectively in patients with peripheral vascular disease. Some patients have their AAA detected incidentally, whilst ultrasound examination of the abdomen is carried out for other indications. These patients have the opportunity to undergo surveillance or elective surgery. The mortality rate of emergency surgical intervention following rupture (50%) is far worse in comparison to that of patients undergoing planned intervention under specialist vascular surgeons (5%). Despite improvements in outcomes from elective intervention for AAA as a result of specialisation, the overall mortality from this condition remains very high (80%) as the commonest presentation of an AAA is rupture. Screening all men aged 65-74 years is considered too costly in the current economic climate. However the cost difference between elective repair and emergency repair of AAA must be considered given that the outcome from elective AAA repair is far superior to that following ruptured AAA repair. Our objective was to retrospectively collect costs and outcomes of elective and emergency AAA repair in order to carry out a cost-effectiveness analysis. Four multiprofessional teams in accident and emergency, operation theatres, intensive care, and surgical wards at the Kent and Canterbury Hospital were selected from health-care professionals including doctors, managers, nurses, and clerical staff with the purpose of obtaining costs. Detailed cost data collection sheets were prepared to calculate costs, which included staff costs, consumables including drugs, intravenous fluids, equipment, investigations, laundry, catering, and stationery. An inventory of costs per item was obtained, and the total cost was calculated from the number of items used. Outcomes were measured in terms of survival. The total costs of emergency AAA repair were pounds sterling 96,700.69, with a cost per life saved of pounds sterling 24,175.17. The total cost of elective AAA repair was pounds sterling 76,583.22, with a cost per life saved of pounds sterling 5,470.23. Emergency intervention for AAA was found to cost five times more than a planned intervention per life saved per year.

Review of prevalence and outcome of vascular disease in patients with diabetes mellitus

OBJECTIVES

Review the literature to determine the prevalence and outcome in patients with diabetes that undergo surgery to correct carotid artery stenosis, lower extremity arterial disease, and abdominal aortic aneurysm (AAA).

DESIGN AND MATERIALS

Studies were obtained from searches over the past 15 years on the National Library of Medicine's online search engine.

RESULTS

The review demonstrated an equivalent prevalence of carotid artery stenosis requiring surgery in patients with diabetes, it favored no increase risk of post-CEA stroke, and it was split on perioperative morbidity and mortality risk. There was an increase prevalence of lower extremity arterial disease requiring surgery in patients with diabetes, it favored equivalent patency and limb salvage rates, and it was split on the morbidity and mortality risk. The review demonstrated a decrease in AAA prevalence among patients with diabetes, it found an increase in the morbidity risk, and equivalent mortality risk.

CONCLUSIONS

Stroke, graft patency, and limb salvage rates in patients with diabetes after surgery are similar to patients without diabetes; however, their risk of complications is increased after surgery and the mortality risk may be higher after CEA.

Risk factors associated with abdominal aortic aneurysm: a population-based study with historical and current data

OBJECTIVES

To define risk factors associated with the development of abdominal aortic aneurysm (AAA) in a population-based case-control study.

MATERIAL AND METHODS

Thirty-five patients found to have AAA at screening were compared with 140 age- and sex-matched controls. Three distinct comparisons were made. Current risk factors in both cohorts were compared. Because data were also available for both cohorts from a study conducted 12 years previously, a historical comparison was made between risk factors identified at the time of this initial evaluation. A longitudinal comparison was made between historical and current risk factors.

RESULTS

Elevated low-density-lipoprotein cholesterol, total cholesterol, and triglyceride levels 12 years before AAA screening were associated with current AAA with an odds ratio (OR) of 2.3 (95% confidence interval [CI], 1.2 to 4.4); OR, 1.9 (95% CI, 1.3 to 2.8); and OR, 1.9 (95% CI,1.2 to 3.1)/mmol/L, respectively. Current variables assessed at AAA screening that were associated with AAA were: A history of atherosclerotic disease, OR, 3.8 (95% CI, 1.7 to 8.5); having a first-degree relative with AAA, OR, 4.4 (95% CI, 1.5 to 13.0); current smoking, OR, 5.2 (95% CI, 1.6 to 16.8); high-density-lipoprotein cholesterol level, OR, 0.1 (95% CI, 0.02 to 0.7)/mmol/L; and high-sensitivity C-reactive protein (hsCRP) level, OR, 1.1 (95% CI, 1.01 to 1.2)/mg/L. Hypertension and diabetes were not associated with AAA. A significant increase of hsCRP over time (12 years) was observed in AAA patients ( P = .039) but not among controls. The variables of a history of atherosclerosis, smoking, and family history of AAA appear to interact synergistically to increase the prevalence of AAA ( P < .001).

CONCLUSION

Among traditional risk factors for atherosclerosis, some were associated with AAA and others were not, indicating complex and partly different causes. Inflammation and heredity appear to be important factors in the development of AAA.

Increased Growth Rate of Abdominal Aortic Aneurysms in Women. The Tromsø Study

OBJECTIVES

The present study was undertaken in order to assess the effect of gender on the growth rate of abdominal aortic aneurysms (AAAs).

METHODS

One hundred and eighty-five men and 49 women with AAAs were studied, mean follow-up 62 months, giving 14,544 patient-months of follow-up. A mean of 16 ultrasound examinations was performed on each patient.

RESULTS

The mean growth rate was 1.82; 1.65 and 2.43 mm per year in men and women, respectively. In a weighted linear regression analysis, high initial diameter and female gender were independent and significant (p < 0.001 and p = 0.003, respectively) predictors for increased growth rate of AAAs. None of the other considered risk factors predicted the growth rate.

CONCLUSIONS

This is the first study to report a significantly different growth rate of AAAs in females compared to males. It, thus, adds evidence to the view that AAA is a more malignant condition in females than in males and could have implications for the frequency of follow-up in women.

High prevalence of unsuspected abdominal aortic aneurysms in patients hospitalised for surgical coronary revascularisation

OBJECTIVES

Prevalence of abdominal aortic aneurysms (AAA) is not exactly known among patients with coronary artery disease (CAD) who are considered for surgical revascularisation. We evaluated the value of screening AAA among coronary patients admitted in our cardiovascular surgery unit.

METHODS

Over a 24-month period, an abdominal echography was proposed to male patients aged 60 or more while hospitalised for surgical coronary revascularisation. Patients with previous investigation of the aorta were excluded. The aorta was considered aneurysmal when the anterior-posterior diameter was of 30 mm or more.

RESULTS

Three hundred and ninety-five consecutive patients all accepted a proposed abdominal echographic screening for AAA. Forty unsuspected AAA were detected (10.1%). The mean diameter was 38.9 +/- 1.3 mm. Four AAA were larger than 50 mm and considered for surgery after the CABG procedure. Surveillance was proposed to the other 36, especially the 10 patients with an AAA larger than 40 mm. Patients with AAA were significantly older than those without AAA (71.3 +/- 0.8 vs. 69.4 +/- 0.3 years, P<0.05). Smoking history (P<0.05) and hypertension (P<0.05) were also associated more frequently with AAA. More than 16% of the patients being smokers and suffering hypertension presented with unsuspected AAA.

CONCLUSIONS

In-hospital screening of AAA is very efficient among patients with coronary artery disease. Therefore, patients with CAD may be considered for routine AAA screening.

LDL Cholesterol is Associated with Small Abdominal Aortic Aneurysms

OBJECTIVE

To examine the relationship between serum lipids and abdominal aortic aneurysms (AAA).

METHODS

Two hundred and six males (>50 years) with AAA (> or =30 mm) detected in a population based screening programme were compared with 252 age-matched male controls in a nested case-control study. Smoking status, previous medical and family histories, height, weight, blood pressure, ankle brachial pressure index (ABPI) and non-fasting lipid profile were recorded.

RESULTS

Cases were found to have significantly higher LDL cholesterol than controls. LDL cholesterol was an independent predictor of the risk for aneurysms in a logistic regression model adjusting for smoking status, family history of AAA, history of ischaemic heart disease, presence of peripheral vascular disease, use of lipid lowering medication and treatment for hypertension. There was a linear effect with increased levels of LDL cholesterol increasing the risk of having a small aneurysm (test for trend p=0.03).

CONCLUSION

The highly significant association between LDL cholesterol and small aneurysms suggests that LDL, possibly acting via inflammatory mediated matrix degeneration, could be an initiating factor in the development of AAA. The ability of statin therapy to prevent AAA formation requires further investigation.

Systemic levels of cotinine and elastase, but not pulmonary function, are associated with the progression of small abdominal aortic aneurysms

OBJECTIVE

to study whether smoking and impaired pulmonary function are associated with the expansion of abdominal aortic aneurysms (AAA).

METHODS AND MATERIAL

seventy-nine men with small (3-5 cm), screen-detected AAA underwent a simple 5-step smoking history, measurement of the forced first second expiratory volume (FEV1), venepuncture and annual ultrasound scan for mean follow-up period of 3.5 years.

RESULTS

all but one patient had a significantly reduced FEV1 (p<0.05, Mann-Whitney). The FEV1/expected FEV1 ratio (rFEV1) was not related to AAA expansion but was negatively correlated with P-elastase-alpha1-antitrypsin-complexes (P-Elastase). P-Elastase was positively correlated with smoking and S-cotinine. Smoking, S-cotinine, and P-elastase were positively correlated with the mean annual AAA expansion rate but not rFEV1.

CONCLUSION

in general, patients with AAA have impaired pulmonary function. A simple five step smoking classification is as predictive of AAA-expansion as S-cotinine. Smoking may cause elastase secretion leading to pulmonary and aortic elastin degradation but the lack of association between AAA-expansion and rFEV1 suggest that other mechanisms are important.

Mass screening on abdominal aortic aneurysm in men aged 60 to 65 years in The Netherlands. Impact on life expectancy and cost-effectiveness using a Markov model

OBJECTIVES

To predict the costs and effects on life expectancy of an AAA screening programme.

METHODS

A Markov model was designed to compare the effects of a single screening for a cohort of men 60-65 years with the current no screening strategy. The following health states were distinguished: no AAA, unknown small AAA, follow-up small AAA, unknown large AAA, repaired AAA, rejected large AAA and death. Transition rates between the health states were simulated using cycle times of one year. Transition probabilities were derived from literature and a previous feasibility study. Incremental costs per life year saved were calculated. Sensitivity analyses and discounting for future effects were performed.

RESULTS

The expected individual AAA costs for non-screening and AAA screening were euro; 196 and euro; 530 respectively. A difference of 3.5 months life expectancy was found in favour of screening leading to euro; 1176/life-year gained. Costs increased as compliance fell. With a discount rate of 4% the costs are euro; 2021/life-year gained.

CONCLUSIONS

One-time ultrasonographic screening for AAA in men aged 60-65 years appears to be cost-effective.

Mortality, morbidity, and costs of ruptured and elective abdominal aortic aneurysm repairs in Nova Scotia, Canada

Ruptured abdominal aortic aneurysms (RAAA) have a 78-94% mortality rate. If cost-effectiveness of screening programs for abdominal aortic aneurysms (AAA) are to be assessed, direct costs for RAAA repairs and elective AAA (EAAA) repairs are required. This study reports mortality, morbidity, and direct costs for RAAA and EAAA repairs in Nova Scotia in 1997-1998 and also compares Nova Scotia and U.S. costs. We performed a retrospective study of 41 consecutive RAAA and 48 randomly selected EAAA patients. Average total costs for RAAA repair were significantly greater than those for EAAA repair (direct costs: $15,854 vs. $9673; direct plus overhead costs: $18,899 vs. $12,324 [pricing in 1998 Canadian dollars]). Intensive care unit length of stay and blood product usage were the most substantial direct cost differentials ($3593 and $2106). Direct cost for preoperative testing and surveillance was greater in the EAAA group ($839 vs. $33). Estimates of U.S. in-hospital RAAA and EAAA repair costs are more than 1.5 times Nova Scotia costs. Direct in-hospital RAAA repair costs are $6181 more than EAAA repair costs. These in-hospital cost data are key cost elements required to assess the cost-effectiveness of various screening strategies for earlier detection and monitoring of AAA within high-risk populations in Canada. Further studies are required to estimate cost per quality-adjusted-life-year gained for various AAA screening and monitoring strategies in Canada.

Alcohol consumption and risk for increased aortic pulse wave velocity in middle-aged Japanese men

A 9-year longitudinal study was performed to prospectively examine the association of alcohol consumption with development of increased aortic pulse wave velocity (PWV) in 1,358 Japanese men aged 35 to 59 years with a PWV less than 8.0 m/sec and without antihypertensive medication. Three hundred fifty-nine men developed increased aortic PWV of 8.0 m/sec or more during 10,598 person-years follow-up. After controlling for potential predictors of aortic PWV, the relative risk for increased aortic PWV compared with that in nondrinkers was 1.05 (95% confidence interval [CI], 0.70 to 1.58) for those who drank 0.1 to 22.9 g/day of ethanol, 1.58 (95% CI, 0.89 to 1.91) for those who drank 23.0 to 45.9 g/day of ethanol, 1.77 (95% CI, 1.24 to 2.53) for those who drank 46.0 to 68.9 g/day of ethanol, and 1.81 (95% CI, 1.23 to 2.66) for those who drank 69.0 or more g/day of ethanol (p for trend <0.001). The relative risk for increased aortic PWV in current drinkers vs nondrinkers was stronger among men with a body mass index (BMI) less than 24.2 kg/m2 and nonsmokers than among men with a BMI 24.2 kg/m2 or more and current smokers, respectively. These results suggest that alcohol consumption is closely associated with risk for increased aortic PWV in middle-aged Japanese men.