Background: Whether elective surgical repair of small abdominal aortic aneurysms improves survival remains controversial.Methods: We randomly assigned patients 50 to 79 years old with abdominal aortic aneurysms of 4.0 to 5.4 cm in diameter who did not have high surgical risk to undergo immediate open surgical repair of the aneurysm or to undergo surveillance by means of ultrasonography or computed tomography every six months with repair reserved for aneurysms that became symptomatic or enlarged to 5.5 cm. Follow-up ranged from 3.5 to 8.0 years (mean, 4.9).Results: A total of 569 patients were randomly assigned to immediate repair and 567 to surveillance. By the end of the study, aneurysm repair had been performed in 92.6 percent of the patients in the immediate-repair group and 61.6 percent of those in the surveillance group. The rate of death from any cause, the primary outcome, was not significantly different in the two groups (relative risk in the immediate-repair group as compared with the surveillance group, 1.21; 95 percent confidence interval, 0.95 to 1.54). Trends in survival did not favor immediate repair in any of the prespecified subgroups defined by age or diameter of aneurysm at entry. These findings were obtained despite a low total operative mortality of 2.7 percent in the immediate-repair group. There was also no reduction in the rate of death related to abdominal aortic aneurysm in the immediate-repair group (3.0 percent) as compared with the surveillance group (2.6 percent). Eleven patients in the surveillance group had rupture of abdominal aortic aneurysms (0.6 percent per year), resulting in seven deaths. The rate of hospitalization related to abdominal aortic aneurysm was 39 percent lower in the surveillance group.Conclusions: Survival is not improved by elective repair of abdominal aortic aneurysms smaller than 5.5 cm, even when operative mortality is low.

Background: Little is known about the rate at which new abdominal aortic aneurysms (AAAs) develop or whether screening older men for AAA, if undertaken, should be limited to once in a lifetime or repeated at intervals.Methods: A large population of veterans, aged 50 through 79 years, completed a questionnaire and underwent ultrasound screening for AAA. Of these, 5151 without AAA on the initial ultrasound (defined as infrarenal aortic diameter of 3.0 cm or larger) were selected randomly to be invited for a second ultrasound screening after an interval of 4 years. Local records and national databases were searched to identify deaths and AAA diagnoses made during the study interval in subjects who did not attend the rescreening.Results: Of the 5151 subjects selected for a second screening, 598 (11.6%) had died (none due to AAA), and 20 (0.4%) had an interim diagnosis of AAA. A second screening was performed on 2622 (50.9%), of whom 58 (2.2%; 95% confidence interval, 1.6%-2.8%) had new AAA. Three new AAAs were 4.0 to 4.9 cm, 10 were 3.5 to 3.9 cm, and 45 were 3.0 to 3.4 cm. Independent predictors of new AAA at the second screening included current smoker (odds ratio, 3.09; 95% confidence, 1.74-5.50), coronary artery disease (odds ratio, 1.81; 95% confidence interval, 1.07-3.07), and, in a separate model using a composite variable, any atherosclerosis (odds ratio, 1.97; 95% confidence interval, 1.16-3.35). Adding the interim and rescreening diagnosis rates suggests a 4-year incidence rate of 2.6%. Rescreening only in subjects with infrarenal aortic diameter of 2.5 cm or greater on the initial ultrasound would have missed more than two thirds of the new AAAs.Conclusions: A second screening is of little practical value after 4 years, mainly because the AAAs detected are small. However, the incidence that we observed suggests that a second screening after longer intervals (ie, more than 8 years) may provide yields similar to those seen in initial screening and therefore warrants further study.

BACKGROUND:We previously reported the prevalence and associations of abdominal aortic aneurysm (AAA) in 73451 veterans aged 50 to 79 years who underwent ultrasound screening.OBJECTIVE:To understand the prevalence of and principal positive and negative risk factors for AAA, and to assess reproducibility of our previous findings.METHODS:In the new cohort of veterans undergoing screening, 52 745 subjects aged 50 to 79 without history of AAA underwent successful ultrasound screening for AAA, after completing a questionnaire on demographics and potential risk factors.RESULTS:We detected AAA of 4.0 cm or larger in 613 participants (1.2%; compared with 1.4% in the earlier cohort). The direction and magnitude of the important associations reported in the first cohort were confirmed. Respective odds ratios for the major associations with AAA for the second and for the combined cohorts were as follows: 1.81 and 1.71 for age (per 7 years), 0.12 and 0. 18 for female sex, 0.59 and 0.53 for black race, 1.94 and 1.94 for family history of AAA, 4.45 and 5.07 for smoking, 0.50 and 0.52 for diabetes, and 1.60 and 1.66 for atherosclerotic diseases. The excess prevalence associated with smoking accounted for 75% of all AAAs of 4.0 cm or larger in the total population of 126 196. Associations for AAA of 3.0 to 3.9 cm were similar but tended to be somewhat weaker.CONCLUSIONS:Our findings confirm our previous cohort findings. Age, smoking, family history of AAA, and atherosclerotic diseases remained the principal positive associations with AAA, and female sex, diabetes, and black race remained the principal negative associations.

PURPOSE:To assess the effects of age, gender, race, and body size on infrarenal aortic diameter (IAD) and to determine expected values for IAD on the basis of these factors. METHODS:Veterans aged 50 to 79 years at 15 Department of Veterans Affairs medical centers were invited to undergo ultrasound measurement of IAD and complete a pre-screening questionnaire. We report here on 69,905 subjects who had no previous history of abdominal aortic aneurysm (AAA) and no ultrasound evidence of AAA (defined as IAD > or = 3.0 cm). RESULTS:Although age, gender, black race, height, weight, body mass index, and body surface area were associated with IAD by multivariate linear regression (all p < 0.001), the effects were small. Female sex was associated with a 0.14 cm reduction in IAD and black race with a 0.01 cm increase in IAD. A 0.1 cm change in IAD was associated with large changes in the independent variables: 29 years in age, 19 cm or 40 cm in height, 35 kg in weight, 11 kg/m2 in body mass index, and 0.35 m2 in body surface area. Nearly all height-weight groups were within 0.1 cm of the gender means, and the unadjusted gender means differed by only 0.23 cm. The variation among medical centers had more influence on IAD than did the combination of age, gender, race, and body size. CONCLUSIONS:Age, gender, race, and body size have statistically significant but small effects on IAD. Use of these parameters to define AAA may not offer sufficient advantage over simpler definitions (such as an IAD > or = 3.0 cm) to be warranted.

BACKGROUND:Independent risk factors for abdominal aortic aneurysm (AAA) have not been clearly defined in multivariable analyses of large patient populations.OBJECTIVE:To identify factors that are independently associated with AAA and to determine the prevalence of previously unrecognized AAA in defined demographic and risk groups.DESIGN:Cross-sectional screening study.SETTING:15 Department of Veterans Affairs medical centers.PARTICIPANTS:73451 veterans who were 50 to 79 years of age and had no history of AAA.MEASUREMENTS:The results of ultrasonographic screening for AAA and a prescreening questionnaire were analyzed using multiple logistic regression.RESULTS:An AAA of 4.0 cm or larger was detected in 1031 participants (1.4%). Smoking was the risk factor most strongly associated with AAA; the odds ratio (OR) for AAAs of 4.0 cm or larger compared with normal aortas (infrarenal aortic diameter < 3.0 cm) was 5.57 (95% CI, 4.24 to 7.31). The association between smoking and AAA increased significantly with the number of years of smoking and decreased significantly with the number of years after quitting smoking. The excess prevalence associated with smoking accounted for 78% of all AAAs that were 4.0 cm or larger in the study sample. Female sex (OR, 0.22 [CI, 0.07 to 0.68]), black race (OR, 0.49 [CI, 0.35 to 0.69]), and presence of diabetes (OR, 0.54 [CI, 0.44 to 0.65]) were negatively associated with AAA. A family history of AAA was positively associated with AAA (OR, 1.95 [CI, 1.56 to 2.43]) but was reported by only 5.1% of participants. Other independently associated factors included age, height, coronary artery disease, any atherosclerosis, high cholesterol levels, and hypertension.CONCLUSIONS:Abdominal aortic aneurysm is associated with multiple factors. Smoking was the risk factor most strongly associated with AAA and may be responsible for most clinically important cases of previously undiagnosed AAA.

Purpose: To assess the effects of age, gender, race, and body size on infrarenal aortic diameter (IAD) and to determine expected values for IAD on the basis of these factors.Methods: Veterans aged 50 to 79 years at 15 Department of Veterans Affairs medical centers were invited to undergo ultrasound measurement of IAD and complete a prescreening questionnaire. We report here on 69,905 subjects who had no previous history of abdominal aortic aneurysm (AAA) and no ultrasound evidence of AAA (defined as IAD greater than or equal to 3.0 cm).Results: Although age, gender, black race, height, weight, body mass index, and body surface area were associated with IAD by multivariate linear regression (all p < 0.001), the effects were small. Female sex was associated with a 0.14 cm reduction in IAD and black race with a 0.01 cm increase in IAD. A 0.1 cm change in IAD was associated with large changes in the independent variables: 29 years in age, 19 cm or 40 cm in height, 35 kg in weight, 11 kg/m(2) in body mass index, and 0.35 m(2) in body surface area. Nearly all height-weight groups were within 0.1 cm of the gender means, and the unadjusted gender means differed by only 0.23 cm. The variation among medical centers had more influence on IAD than did the combination of age, gender, race, and body size.Conclusions: Age, gender, race, and body size have statistically significant but small effects on IAD. Use of these parameters to define AAA may not offer sufficient advantage over simpler definitions (such as an IAD greater than or equal to 3.0 cm) to be warranted.

PURPOSE: TO define the clinical features and assess the frequency and causes of missed diagnoses of ruptured abdominal aortic aneurysm (AAA) in patients initially presenting to internists.PATIENTS: All identified patients with ruptured AAA presenting to internists during a 7 1/2-year period at a large academic medical center.METHOD: Chart review.RESULTS: We identified 23 patients with a ruptured AAA presenting to internists. Most had abdominal pain and tenderness, back or flank pain, and leukocytosis, whereas anemia and profound hypotension (systolic blood pressure below 90 mm Hg) were uncommon at presentation. In 14 cases (61%), the diagnosis of ruptured AAA was initially missed. Nine patients had an interval of 24 hours or more between presentation to the internist and surgery or death. The diagnosis was not made until after shock developed in nine patients who were hemodynamically stable at presentation. Of 17 patients who underwent surgery, 7 of 8 with preoperative shock died, compared with 2 deaths in 9 patients (p <.02) without shock. All six patients who did not have surgery died, yielding an overall mortality of 65% for the series. Ruptured AAAs were most frequently misdiagnosed as urinary tract obstruction or infection, spinal disease, and diverticulitis. Chart review revealed a general lack of physician awareness of the syndromes of contained rupture of AAA and symptomatic unruptured AAA. CONCLUSIONS: In patients with ruptured AAA who present to internists, the diagnosis is often delayed or missed and this appears to adversely effect survival. Internists should familiarize themselves with the presentation and management of ruptured AAA.