Hospital based screening of 65-73 year old men for abdominal aortic aneurysms in the county of Viborg, Denmark

Routine screening for asymptomatic abdominal aortic aneurysm in high-risk patients is not recommended in emergency departments that are frequently crowded

OBJECTIVES

The objectives were to examine the feasibility of offering abdominal aortic aneurysm (AAA) screening to consecutive, asymptomatic high-risk patients in a busy emergency department (ED) and to compare the prevalence of undetected AAA among ED patients to the prevalence among similarly aged men from the general population.

METHODS

A prospective cohort study was conducted at an academic community ED with an annual census of 58,000 patients. Dedicated study coordinators attempted to approach all consecutive male ED patients >50 years who presented in June-August 2007 during hours of high patient volume. To be eligible, older males had to have a smoking history or a family history of AAA. Patients were excluded if they presented with AAA symptoms, had a previous history of AAA screening or repair, had hemodynamic instability, or had an altered mental status. Study coordinators completed a brief interview with all enrolled subjects to obtain demographic and health information. A credentialed ED provider performed the ultrasound (US) screening exam and documented all findings. The US director reviewed representative images of the sonographic exam for correct visualization and measurement during quality assurance. The ED sonographers also completed a survey regarding their attitudes toward AAA screening in the ED. The primary study outcomes were the feasibility of AAA screening in the ED (screening rate, enrollment rate, US success rate, and providers' opinions) and the prevalence of AAA (aortic diameter of > or =3.0 cm) in the study sample.

RESULTS

During the 12-week study period, the study coordinators successfully approached 96% (700/729) of males > 50 years who were in the ED during study enrollment hours. Of those approached, 278 were eligible (40%), 25% were ineligible, 20% were not at high risk, and for 15% we could not determine risk factor status because of altered mental status. Of the 278 eligible, 196 (70%) underwent an US exam; 10% were not scanned because the providers were too busy, and 20% declined participation. Of those scanned, the ED sonographer was able to completely visualize and correctly measure the abdominal aortas of 71% of subjects. The prevalence rate of AAA in the study sample was 5.7% (95% confidence interval [CI] = 1.9% to 9.6%), similar to reported rates of 6 or 7% in other studies. More than half of the ED sonographers reported that US screening for AAA improved the quality of ED care (58%) and patient satisfaction (63%). However, 47% reported that AAA screening reduced ED efficiency, and 74% felt that the ED was not an appropriate setting for routine AAA screening.

CONCLUSIONS

Routine screening for asymptomatic AAA required substantial ED resources for a relatively low success rate of completed screens. The prevalence rate of AAA in our ED sample was not significantly different than prevalence estimates obtained from older men in the general population. ED sonographers reported benefits of screening in terms of improving the quality of emergency care and patient satisfaction, but also reported that it reduced operational efficiency. For EDs that have problems with crowding, we do not recommend implementing a routine screening program for AAA, even among high-risk patients.

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.

Screening for abdominal aortic aneurysm

BACKGROUND

Abdominal aortic aneurysm (AAA) is found in 5% to 10% of men aged 65 to 79 years. The major complication is rupture which presents as a surgical emergency. The mortality after rupture is high, 80% for patients reaching hospital and 50% for those undergoing surgery for emergency repair. Currently elective surgical repair is recommended for aneurysms discovered to be larger than 5.5 cm to prevent rupture. There is interest in population screening to detect, monitor and repair abdominal aortic aneurysms before rupture.

OBJECTIVES

To determine the effects of screening asymptomatic individuals for AAA on mortality, subsequent treatment, quality of life and cost effectiveness of screening.

SEARCH STRATEGY

The Cochrane Peripheral Vascular Diseases Group searched their Trials Register (last searched 26 January 2007) and CENTRAL (last searched Issue 1, 2007).

SELECTION CRITERIA

Randomised controlled trials of population screening for AAA.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials and extracted data.

MAIN RESULTS

Four studies involving 127,891 men and 9,342 women were included in this review. Only one study included women. Results for men and women were analysed separately. Three to five years after screening there was no significant difference in all-cause mortality between screened and unscreened groups for men or women (men, odds ratio (OR) 0.95; 95% Confidence interval (CI) 0.85 to 1.07; for women OR 1.06; 95% CI 0.93 to 1.21). There was a significant decrease in mortality from AAA in men (OR 0.60; 95% CI 0.47 to 0.78), but not for women (OR 1.99; 95% CI 0.36 to 10.88). In this analysis mortality includes death from rupture and from emergency or elective surgery for aneurysm repair. There was also a decreased incidence of ruptured aneurysm in men (OR 0.45; 95% CI 0.21 to 0.99) but not in women (OR 1.49; 95% CI 0.25 to 8.94). There was a significant increase in surgery for AAA in men (OR 2.03; 95% CI 1.59 to 2.59). This was not reported in women. There were no data on life expectancy, complications of surgery or subjective quality of life.

AUTHORS' CONCLUSIONS

There is evidence of a significant reduction in mortality from AAA in men aged 65 to 79 years who undergo ultrasound screening. There is insufficient evidence to demonstrate benefit in women. The cost effectiveness may be acceptable, but needs further expert analysis. These findings need careful consideration in judging whether a co-ordinated population-based screening programme should be introduced.

High-risk and low-risk screening for abdominal aortic aneurysm both reduce aneurysm-related mortality. A stratified analysis from a single-centre randomised screening trial

BACKGROUND

Cardiovascular diseases and chronic obstructive pulmonary disease (COPD) are both associated with abdominal aortic aneurysms (AAA). The aim of this study was therefore to analyse whether screening for AAA could be restricted to men with such diseases (high risk group).

METHODS

Before the date of randomisation of a population screening trial of 12,639 64-73-year-old males, all discharge diagnoses from the National Patient Registry concerning AAA-related diseases were merged with the screening results on attendance, AAA prevalence, and AAA-related mortality and overall mortality. Differences in proportions were compared by Chi square tests and differences in mortality by Cox regression analyses.

RESULTS

The attendance rate was 78.8% and 6.7% had an AAA in the high risk group compared to 75.8% attendance (P<0.001) and 2.9% (P<0.001) in the remaining population. Cumulatively, screening of only high risk men with would have required 72.9% (95% C.I.: 72.3-74.5%) fewer screening invitations, would have discovered 46.1% (95% C.I.: 38.9-53.4%) of the AAA cases diagnosed and prevented 46.7% (95% C.I.: 28.3-65.7%) of the AAA-related deaths. However, screening decreased AAA-related mortality both among men with and without known COPD or cardiovascular diseases: mortality ratio: 0.22 (95% C.I.: 0.08-0.65), P=0.006, and 0.24 (95% C.I: 0.09-0.63, P=0.004, respectively.

CONCLUSION

High-risk population screening would prevent less than half of AAA-related deaths. Therefore, restricting screening to such high-risk groups does not seem justified, but cost effectiveness analyses are needed to reach a firm conclusion.

Relatively High Pulmonary and Cardiovascular Mortality Rates in Screening-detected Aneurysmal Patients Without Previous Hospital Admissions

BACKGROUND

Men with abdominal aortic aneurysm (AAA) who are not hospitalised for pulmonary and cardiovascular diseases may have higher mortality due to such disorders.

MATERIAL AND METHODS

Previous discharge diagnoses and causes of death were collected for 4,816 men aged 64-73 years attending mass screening for AAA. Of these, 191 (4%) had an AAA. Overall, cardiovascular- and pulmonary-disease-specific mortality was compared for men with and without AAA stratified for earlier pulmonary or cardiovascular hospitalisations by Cox's proportional hazards regression while adjusting for age. Absolute risk differences after five years were calculated by life table analysis.

RESULTS

The median observation time was 63 months. 362 men died from cardiovascular causes other than AAA, and 144 died from pulmonary causes. The cardiovascular mortality was significantly higher in aneurysm patients without previous related hospitalisation (HR=4.35, 95% CI: 2.73-6.94, P<0.001) with an absolute mortality difference after 5 years of 16.3% (95% CI: 10.2-22.5%). Pulmonary-cause mortality was higher among men with AAA both with and without previous hospitalisation for pulmonary causes (HR=3.05; 95% CI: 1.19-7.83, P=0.020, and HR=3.29; 95% CI: 1.78-6.08, P<0.001, respectively).

CONCLUSIONS

Men with AAA who had not been hospitalised for cardiovascular diseases have more than four times higher cardiovascular mortality. Studies of cohorts being offered relevant prophylaxis may clarify the potential benefits of general preventive actions.

Preliminary Ten Year Results from a Randomised Single Centre Mass Screening Trial for Abdominal Aortic Aneurysm

BACKGROUND

At present, several regions and countries are considering screening for abdominal aortic aneurysm (AAA). However, The Chichester Aneurysms Screening Trial has reported poor long term benefit of screening for AAA. We therefore supplement previously published data with a preliminary analysis of the ten-year mortality from AAA, based upon population-based data until 2002 (7 years) and incomplete hospital-based information on deaths until 2005 (10 years).

METHODS AND MATERIAL

In 1994 we started a randomised screening trial of 12,639 64-73 year-old males; 6,306 were controls, and 6,333 were invited to an abdominal ultrasound scan at their district hospital. Information on all deaths until 15.3.2005 was obtained from the Office of Civil Registration. Information on AAA related deaths was obtained from the national registry of Causes of Deaths from 1.4.1994 to 31.12.2001, and supplemented with AAA deaths known to the Danish National Patient Registry until 15.3.2005. Operations were obtained from the Danish National Vascular Registry from 1.4.1994 to 15.3.2005. Death certificates and medical records were reviewed by two independent assessors. The analyses were based on "intention to treat" from the date of randomisation.

RESULTS

The attendance rate was 76.6% and 191 (4.0%) had an AAA. The median observation time was 9.58 years. In the invited group 13 subjects were acutely operated on compared to 40 in the control group (Risk ratio: 0.32 (95% C.I. 0.17-0.60, P<0.001)), and 14 died due to AAA compared to 51 in the control group (Hazard ratio: 0.27 (95% C.I.: 0.15-0.49, P<0.001).

CONCLUSION

Over ten years, screening reduced mortality from AAA by 73%, and the frequency of emergency operations by 68%.

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.

Cost-effectiveness Analysis of Screening for Abdominal Aortic Aneurysms Based on Five Year Results from a Randomised Hospital Based Mass Screening Trial☆

BACKGROUND

The aim of this study was to estimate the cost effectiveness of screening for abdominal aortic aneurysm (AAA).

MATERIAL AND METHODS

All 12,639 men born in the years 1921-1933 (aged 64-73) living in Viborg County, Denmark, were randomly allocated either to receive an invitation to abdominal ultrasound scanning for AAA or to be controls. Costs for screening and surveillance were assessed prospectively. Diagnosis Related Group (DRG) costs from 1999 were used concerning admissions with uncomplicated and complicated operations. Admissions for AAA surgery were retrospectively classified according to complications in patient records.

RESULTS

Mean follow-up time was 52 months. 76.6% of invited men attended screening, and 191 (4.0%) had an AAA. As previously reported, the cumulative 5-year AAA-specific mortality in the invited group was significantly reduced by 67% compared to the control group (P = 0.003). The costs were estimated to be Euro 11.23 per scan. The costs per life-year saved were Euro 9057 (Euro 5872-20,063) after 5 years, and were expected to decrease to Euro 2708 (Euro 1758-6031) after 10 years and to Euro 1825 (Euro 1185-4063) after 15 years.

CONCLUSION

Screening of 64-73 years old males in Denmark seems cost effective.

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

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

Screening for abdominal aortic aneurysms: single centre randomised controlled trial

OBJECTIVE

To determine whether screening Danish men aged 65 or more for abdominal aortic aneurysms reduces mortality.

DESIGN

Single centre randomised controlled trial.

SETTING

All five hospitals in Viborg County, Denmark.

PARTICIPANTS

All 12,639 men born during 1921-33 and living in Viborg County. In 1994 we included men born 1921-9 (64-73 years). We also included men who became 65 during 1995-8.

INTERVENTIONS

Men were randomised to the intervention group (screening by abdominal ultrasonography) or control group. Participants with an abdominal aortic aneurysm > 5 cm were referred for surgical evaluation, and those with smaller aneurysms were offered annual scans.

OUTCOME MEASURES

Specific mortality due to abdominal aortic aneurysm, overall mortality, and number of planned and emergency operations for abdominal aortic aneurysms.

RESULTS

4860 of 6333 men were screened (attendance rate 76.6%). 191 (4.0% of those screened) had abdominal aortic aneurysms. The mean follow-up time was 52 months. The screened group underwent 75% (95% confidence interval 51% to 91%) fewer emergency operations than the control group. Deaths due to abdominal aortic aneurysms occurred in nine patients in the screened group and 27 in the control group. The number needed to screen to save one life was 352. Specific mortality was significantly reduced by 67% (29% to 84%). Mortality due to non-abdominal aortic aneurysms was non-significantly reduced by 8%. The benefits of screening may increase with time.

CONCLUSION

Mass screening for abdominal aortic aneurysms in Danish men aged 65 or more reduces mortality.

Effectiveness and cost of screening for abdominal aortic aneurysm: results of a population screening program

OBJECTIVES

We undertook this study to calculate the cost per life-year gained in the first round of a screening program for abdominal aortic aneurysm (AAA) and to estimate the costs in a subsequent round.

METHODS

This was an intervention study, with follow-up for ruptured aneurysms. Men older than 50 years were screened for asymptomatic AAA. Outcome measures included cost per life-year saved and number of men needed to be screened to save one life.

RESULTS

The incidence of ruptured AAA was 2.6 per 10,000 person- years in the screening group and 7.1 per 10,000 person-years in the control group. Screening is estimated to have prevented 10.8 ruptured AAA and 8 deaths per year, gaining 51 life-years per year for the study population, and to have reduced the incidence of ruptured AAA by 64% (95% CI, 42%-77%). Each life-year gained during the first screening round cost $1107. To save one life, 1000 men need to be screened and 5 elective operations performed. We predict that a second round of screening can be cost neutral.

CONCLUSIONS

The cost-effectiveness of screening for AAA compares favorably with screening programs for other disorders in adults.

Abdominal aortic aneurysm repair in the veteran population

BACKGROUND

The aim of this study was to audit the outcome of elective open aortic aneurysm repair in a veteran hospital to determine whether age > or =80 years influenced the morbidity or mortality.

METHODS

All elective abdominal aortic aneurysm (AAA) repaired at Greenslopes Private (Repatriation) Hospital between January 1995 and July 2000 were reviewed. Operative details, premorbid condition, postoperative outcomes as well as length of admission were recorded. Patients were grouped according to age as > or =80 years or <80 years.

RESULTS

There were 251 open elective AAA (including infrarenal and suprarenal, as well as recurrent AAA) repairs carried out during this period, 64 of which were patients of age > or =80 years. Cardiovascular risks factors did not differ between groups nor did complication rates for patients > or =80 and <80 years of age (19.1 and 19.8%, respectively). Mortality rates were not significantly different between groups (> or =80 years: 6.25%; <80 years: 4.8%; P > 0.6).

CONCLUSIONS

Age > or =80 years should not be an exclusion criteria when contemplating open elective AAA repair.

Randomized clinical trial of screening for abdominal aortic aneurysm in women

BACKGROUND

Screening for abdominal aortic aneurysm (AAA) is commonly restricted to men. Recent studies have indicated a possible increase in deaths due to ruptured AAA in women, and a higher rate of rupture in women than in men. The present report details results from a randomized controlled trial that assessed the effects of screening women for AAA.

METHODS

Some 9342 women aged 65-80 years were entered into the trial and randomized to age-matched screen and control groups. A single ultrasonographic scan was offered to women in the screening arm of the study. Women with an AAA received follow-up scans, and were considered for elective surgery if certain criteria were met.

RESULTS

The prevalence of AAA was six times lower in women (1.3 per cent) than in men (7.6 per cent). Over 5- and 10-year follow-up intervals, the incidence of rupture was the same in the screened and control groups of women.

CONCLUSION

Screening women for AAA is neither clinically indicated nor economically viable.

Hospital costs and benefits of screening for abdominal aortic aneurysms. Results from a randomised population screening trial

OBJECTIVES

to analyse the hospital costs and benefits of screening older males for abdominal aortic aneurysm (AAA).

MATERIALS AND METHODS

in 1994 a hospital-based screening trial of 12 658 65-73-year-old males was started. AAA >5 cm were referred for surgery. The remaining AAA were offered annual scans. Those with aortic ectasia were rescreened at 5 yearly intervals. AAA-operations and hospital AAA-related deaths were researched. The costs of screening, surveillance, and treatment were also registered.

RESULTS

the attendance rate was 76%; of whom 191 (4.0%) had AAA. Mean observation time was 5.13 years. Sixty in the screened and 41 in the control group were operated (p=0.06), of which 7 and 27 respectively were operated as an emergency (p<0.001), and 6 and 19 respectively died due to AAA (p=0.009). The costs per scan were 83.50 DKK, 81 400 DKK per emergency operation (71 485 DKK after screening), and 117 000 DKK per emergency operation. The cost per prevented hospital death was 67 855 DKK, equivalent to approximately life year saved approx. 7540 DKK (GBP1=12 DKK).

CONCLUSION

screening appears to reduce hospital AAA mortality and to be cost-effective.

Apolipoprotein E genotype is associated with differential expansion rates of small abdominal aortic aneurysms

BACKGROUND

The common polymorphism of the apolipoprotein E (APOE) gene is associated with differential risk of atherosclerosis; the gene could be a candidate gene in abdominal aortic aneurysms (AAA).

METHODS

APOE genotypes were determined in 57 men aged 65-73 years with a small AAA (30-50 mm). The patients were included in a population ultrasonographic screening programme and were followed with at least two examinations during an interval of 2-4.5 years. The AAA expansion rates in patients with four different APOE genotypes were studied, with adjustment for initial AAA size and smoking.

RESULTS

APOE genotype was a significant determinant of AAA expansion rate (P = 0.001). The adjusted mean (95 per cent confidence interval) rate was 2.1 (1.7-2.6) mm/year in 31 men with genotype E3E3, 1.3 (0.7-1.9) mm/year in 17 men with E3E4, 3.1 (2.0-4. 1) mm/year in six men with E2E3 and 4.2 (2.7-5.6) mm/year in three men with E2E4. The mean expansion rate was 2.2 (1.5-2.8) mm/year in non-smokers and 3.0 (2.5-3.6) mm/year in smokers (P = 0.014).

CONCLUSION

APOE genotype seems to influence AAA expansion rate, but the effects of the individual genotypes, in particular E3E3 and E3E4, are contradictory when compared with the effects of the genotypes on risk of atherosclerosis.

Quantifying the risks of hypertension, age, sex and smoking in patients with abdominal aortic aneurysm

BACKGROUND

The prevalence of abdominal aortic aneurysm (AAA) in a community-based sample of men and women aged 65-79 years was correlated with known risk factors. In addition, the effect of high blood pressure and the use of antihypertensive medication on growth of AAAs were studied.

METHODS

Aortic diameter was assessed by ultrasonography and data on risk factors were collected by self-administered questionnaire for 5356 men and women as part of a randomized controlled trial.

RESULTS

Current hypertension increased the risk of having an aortic aneurysm by 30-40 per cent while use of antihypertensive medication increased the risk by 70-80 per cent, adjusting for current blood pressure. There was no clear relationship between hypertension and growth rates of existing aneurysms in this study, although these results were largely from data on small aneurysms. Men were nearly six times more likely to develop an AAA than women; the risk increased by 40 per cent every 5 years after the age of 65 years. Smoking was an independent risk factor for AAA, with level of exposure being more significant than duration.

CONCLUSION

Male sex, smoking and hypertension are strong risk factors for the development of AAA. In this study hypertension did not significantly increase the growth rate of existing aneurysms. Smoking remains the most important avoidable risk factor for AAA. The analyses presented here suggest that selection for screening, other than by age and sex, is not worthwhile.

Epidemiology and potential for prevention of abdominal aortic aneurysm

BACKGROUND

Ruptured abdominal aortic aneurysm (AAA) is a common cause of death which is preventable by elective repair of an asymptomatic AAA.

METHODS

The literature was reviewed with emphasis on epidemiological studies and population-based screening surveys.

RESULTS AND CONCLUSION

The prevalence of small AAA ranges between 3 and 8 per cent. The incidence of asymptomatic AAA seems to be increasing, although exact incidence estimates vary. The most important risk factors for AAA are male sex, age, family history and smoking. Hypertension is associated with a mildly increased risk, but diabetes is not associated with any increase. Primary prevention of AAA is not a realistic option. There is no evidence of an effective medical treatment to prevent growth of small AAAs, although trials with propranolol are under way. The only intervention to prevent death from aneurysm is elective repair of the asymptomatic lesion. Screening for asymptomatic AAA can reduce the incidence of rupture. However, further studies are needed to determine the cost effectiveness of screening compared with that of other health programmes.