Final follow‐up of the Multicentre Aneurysm Screening Study (MASS) randomized trial of abdominal aortic aneurysm screening

Background:

The long‐term effects of abdominal aortic aneurysm (AAA) screening were investigated in extended follow‐up from the UK Multicentre Aneurysm Screening Study (MASS) randomized trial.

Methods:

A population‐based sample of men aged 65–74 years were randomized individually to invitation to ultrasound screening (invited group) or to a control group not offered screening. Patients with an AAA (3·0 cm or larger) detected at screening underwent surveillance and were offered surgery after predefined criteria had been met. Cause‐specific mortality data were analysed using Cox regression.

Results:

Some 67 770 men were enrolled in the study. Over 13 years, there were 224 AAA‐related deaths in the invited group and 381 in the control group, a 42 (95 per cent confidence interval 31 to 51) per cent reduction. There was no evidence of effect on other causes of death, but there was an overall reduction in all‐cause mortality of 3 (1 to 5) per cent. The degree of benefit seen in earlier years of follow‐up was slightly diminished by the occurrence of AAA ruptures in those with an aorta originally screened normal. About half of these ruptures had a baseline aortic diameter in the range 2·5–2·9 cm. It was estimated that 216 men need to be invited to screening to save one death over the next 13 years.

Conclusion:

Screening resulted in a reduction in all‐cause mortality, and the benefit in AAA‐related mortality continued to accumulate throughout follow‐up. Registration number: ISRCTN37381646 ( http://www.controlled‐trials.com ). Copyright © 2012 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.     

Randomisierte Studien mit EBM-Level 1 beweisen es

Results have been published of randomised controlled studies on the screening of elderly men for abdominal aortic aneurysms (AAA). A systematic review and meta-analysis was therefore carried out in order to be able to assess the pooled effects. A Medline search (PubMed) for randomised controlled studies was carried out using the key words “screening” and “aortic aneurysms” in English. The medium-term (3.5-5 years) and long-term (7-15 years) effects were calculated as the odds ratio with a 95% confidence interval. Four studies were identified, the “Chichester Study” (UK/England), the “Multicentre Aneurysm Screening Study” (MASS) (UK/England), the “Western Australian Aneurysm Screening Study” (AUS) and the “Viborg Study” (Denmark). The analysis showed that the probability of an AAA rupture fell significantly by 47% as a result of screening, AAA-related mortality (after men over the age of 80 years were excluded) decreased by 49% and overall mortality was also reduced (OR 0.93; 95% CI: 0.90-0.96). The number of planned operations increased 3-fold (p<0.05) and the probability of emergency operations decreased by 45% (p<0.05). The long-term pooled results showed a significant reduction of 47% in the probability of both AAA rupture and AAA-related mortality and a significant decrease in overall mortality (OR 1.77; 95% CI: 0.92-0.97). Overall, 1.7 times more operations were carried out on the men invited for screening than on the controls (OR 1.77; 95% CI: 1.57; 1.99). AAA screening reduces the probability of rupture and AAA-related mortality by about 50% each and overall mortality by about 6-7%, although there are differences which might have an impact on local cost-benefit ratio of the screening.     

The influence of screening on the incidence of ruptured abdominal aortic aneurysms.

PURPOSE: The purpose of this study was to estimate the influence of a screening program on the incidence and mortality of ruptured abdominal aortic aneurysms (RAAAs). METHODS: The effects of screening on the incidence and death rate of RAAAs were investigated with a stepped wedge study design. RAAAs that occurred in the Huntingdon district were traced with an examination of all hospital records and community postmortem records. RESULTS: During the 5-year period from 1991 to 1996, 78 RAAAs occurred in the Huntingdon district: 62 in men and 16 in women. Eleven of the 62 men with RAAAs had been invited for screening. The incidence of RAAA in the invited group was 3.7 per 10,000 person-years (py; 95% confidence interval [CI], 1.5 - 7.3). In the noninvited group, the incidence was 7.3 per 10,000 py (95% CI, 5.3. - 9.2), a rate ratio of 0.51 (95% CI, 0.26 - 0.97). The mortality of rAAAs in the invited group was 3.0 per 10, 000 py (95% CI, 1.4 - 5.4) as compared with 5.4 per 10,000 py in the noninvited group (95% CI, 3.9 - 7.3), resulting in a rate ratio of 0. 55 (95% CI, 0.26 - 1.15). CONCLUSION: Screening for asymptomatic AAAs can reduce the incidence rate of RAAAs by 49% (95% CI, 3% - 74%).     

Prognostic scoring in ruptured abdominal aortic aneurysm: a prospective evaluation

BACKGROUND: Prospective validation of prognostic scoring systems for ruptured abdominal aortic aneurysm (AAA) is lacking. This study assesses the validity of three established risk scores and a new prognostic index. METHOD: Patients admitted with ruptured AAA during a 26-month period (August 2002-December 2004) were recruited prospectively. The Glasgow Aneurysm Score (GAS), Hardman Index, Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity (POSSUM) scores, and the Edinburgh Ruptured Aneurysm Score (ERAS) were recorded and related to outcome. RESULTS: During the study period, 111 patients were admitted with ruptured AAA. Of these, 84 (76%) underwent attempted operative repair and were included in the study; 37 (44%) died after operation. The GAS, Hardman Index, and the ERAS were statistically related to mortality. However, analysis by receiver-operator characteristic curve revealed the ERAS to have an area under the curve (AUC) of 0.72 (95% confidence interval [CI], 0.61-0.83). The vascular (V)-POSSUM and ruptured AAA (RAAA)-POSSUM models had an AUC of 0.70 (95% CI, 0.59-0.82). The Hardman Index and GAS had an AUC of 0.69 (95% CI, 0.57-0.80) and 0.64 (95% CI, 0.52-0.76), respectively. Although the V-POSSUM equation predicted mortality effectively (P = .086), the RAAA-POSSUM derivative demonstrated a significant lack of fit (P = .009). CONCLUSION: Prospective validation shows that the Hardman Index, GAS, and V-POSSUM and RAAA-POSSUM scores do not perform well as predictors for death after ruptured AAA. The ERAS accurately stratifies perioperative risk but requires further validation.     

Outcome in patients requiring renal replacement therapy after surgery for ruptured and non-ruptured aneurysm of the abdominal aorta.

OBJECTIVES: to study the course of postoperative acute renal failure requiring renal replacement therapy (RRT) in patients with ruptured (RAAA) and non-ruptured (EAAA) aneurysm of the abdominal aorta (AAA) and to investigate the predictive value regarding outcome of parameters collected during the illness. DESIGN: retrospective study in a university hospital. MATERIALS AND METHODS: the records of 42 patients, 21 with RAAA and 21 with EAAA, were reviewed. RESULTS: overall mortality was 69%, 71% for RAAA patients and 66% for EAAA patients. RRT was started 9 (2-28) days - median (range) - postoperatively and continued during 9 (2-50) days. Renal function recovered in nine of the 13 survivors after 18 (2-50) days. Length of ICU stay was 50 (2-132) days for survivors vs. 19 (6-56) days for non-survivors. The systemic inflammatory response syndrome (SIRS) or need for vasoactive support was associated with poor outcome and the ability to wean from vasoactive or ventilatory support with improved outcome. CONCLUSIONS: RAAA and EAAA patients requiring postoperative RRT both had a high mortality. The ICU stay of non-survivors was shorter than that of survivors, who had a 75% chance of regaining renal function. The ability to wean from ventilatory and inotropic support may be of help in the clinical management of patients requiring RRT after AAA surgery.     

Implications of screening for abdominal aortic aneurysms on surgical workload

BACKGROUND: The Multicentre Aneurysm Screening Study (MASS) provided strong evidence for both the clinical benefit and the cost-effectiveness of a screening programme for abdominal aortic aneurysms (AAAs) in men. If a national screening programme for AAA were adopted in the UK, it would be expected to increase the elective and decrease the emergency surgical workload. METHODS: The MASS trial randomized 67,800 men aged 65-74 years to be invited to attend for ultrasonographic screening for AAA or to a control group that received no invitation. Predictions of elective and emergency surgical workload were made for a 20-year interval after the introduction of a screening programme for 65-year-old men, based on surgical rates observed in the MASS trial and national mortality statistics. RESULTS: For a district general hospital serving a population of 400,000, there was an estimated reduction from nine emergency operations per year before introduction of the screening programme to three emergency operations annually in men aged 65 years and over by the end of the 20-year interval, and an increase from 24 to 43 AAA operations overall. The corresponding estimated annual costs for all AAA surgery increased by 47 per cent, from pound 209,000 to pound 308,000. These results were not affected by changes in the underlying assumptions. CONCLUSION: The results support the expectation of very few emergency operations, and principally elective operations, being performed following the introduction of a screening programme. For a typical district general hospital, a screening programme would be expected to lead to two additional elective AAA operations per month, and to save 11 AAA-related deaths per year.     

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.     

Ruptured abdominal aortic aneurysm in the Huntingdon district: a 10-year experience.

A study was undertaken to establish the true incidence of ruptured abdominal aortic aneurysms (RAAA) in the Huntingdon districts. RAAAs in the Huntingdon district between 1986 and 1995 were studied retrospectively. Data were collected from hospital records and hospital and community autopsies. There was a total of 139 cases of RAAA; 119 were males and 20 females, giving a M:F ratio of 6:1. The incidence of RAAAs was 17.8/100,000 person years (py) in males and 3.0/100,000 py in females. Mean age at rupture was 75.5 years in men (95% confidence intervals (CI) 74-78 years) and 80.2 in women (95% CI 78.8-83 years). There was an age-specific increase in incidence after the age of 65 years in men and after 80 years in women, although 12.6% of all RAAAs occurred in men under 65 years. In all, 100 patients were confirmed to have died of RAAA during the 10-year period. This represents 79% of all ruptures discovered. Almost three-quarters of patients did not reach the operating theatre. Of the 61 patients operated on, 29 survived (48%). The size of the aneurysm at rupture was recorded in 68 cases (49%). The mean size was 8.14 cm (SD 2.0 cm). In five cases (7.4%), rupture occurred in AAAs smaller than 6 cm. The overall mortality from RAAA in Huntingdon health district is approximately 80% and three-quarters of all deaths occurred without an operation.     

Late results concerning feasibility and compliance from a randomized trial of ultrasonographic screening for abdominal aortic aneurysm

BACKGROUND: The study was an update at 10 years of a randomized trial of the efficacy of screening for abdominal aortic aneurysm (AAA). The extent of benefit, feasibility and compliance were examined, and reasons why this intervention may fail a proportion of those screened were identified. METHODS: A total of 6058 men aged 65 years and over were randomized to a group invited to attend ultrasonographic screening or to a control group. The mortality rate from AAA in the two arms of the trial was compared using a Poisson model. Analyses were by intention to treat. RESULTS: There was a 21 per cent reduction in mortality rate from AAA over the 10-year follow-up (relative risk 0.79 (95 per cent confidence interval 0.53 to 1.40)). The observed relative mortality reduction peaked at 4 years with a 52 per cent reduction in the study group. Eighteen of 24 AAA deaths in the study group were among those who did not attend the first screen, or failed to comply with the follow-up protocol. CONCLUSION: A greater awareness of the benefits of full participation in a screening programme could provide a larger and sustained mortality reduction.     

Validity of the Glasgow Aneurysm Score and the Hardman Index in predicting outcome after ruptured abdominal aortic aneurysm repair

BACKGROUND: The Glasgow Aneurysm Score and the Hardman Index have been recommended as predictors of outcome after repair of ruptured abdominal aortic aneurysm (AAA). This study aimed to assess their validities. METHODS: Patients admitted to a single unit with a ruptured AAA over a 2-year interval (2000-2001) were identified from a prospectively compiled database. Hospital records of all patients undergoing attempted operative repair were reviewed. The Glasgow Aneurysm Score and the Hardman Index were calculated retrospectively and related to clinical outcome. RESULTS: One hundred patients were admitted with a ruptured AAA. Of these, 82 underwent attempted operative repair and were included in the study: 68 men and 14 women, of median age 73 (range 54-87) years. Thirty (37 per cent) patients died after the operation. The Glasgow Aneurysm Score was a poor predictor of postoperative mortality. The area under the Receiver-Operator Characteristic curve was 0.606 (P = 0.112, 95 per cent c.i. 0.483-0.729). Similarly, the Hardman Index failed to predict postoperative mortality accurately (P = 0.211, chi(2) for trend). Of nine patients in this series with three or more Hardman criteria, generally held to be fatal, six survived. CONCLUSION: Contrary to previous reports, The Glasgow Aneurysm Score and the Hardman Index were poor predictors of postoperative mortality after repair of a ruptured AAA in this study.     

Abdominal aortic aneurysm surgery in a district general hospital: a 15-years experience

The incidence of patients presenting with both ruptured abdominal aortic aneurysm (RAAA) and elective abdominal aortic aneurysm (EAAA) increases with age. The aim of our study was to find out the incidence of RAAA, age and sex groups of patients at risk, and 30-day all-cause perioperative mortality associated with RAAA as well as EAAA repair in a busy district general hospital over a 15-year time period. All patients operated for AAA during 1989-2003, both elective and ruptured, were included in the study. Patients who died in the community from RAAA were also included. The data were collected from the hospital information system, theater logbooks, intensive therapy unit records, postmortem register, and patients' medical notes. We divided the data for RAAA into two groups of 7.5 years each to see if there was any improvement over time in 30-day postoperative mortality. There were 816 cases of AAA, which included 468 RAAAs (57%) and 348 EAAAs (43%). Out of 468 RAAAs, 243 patients had emergency repair, of whom 213 were males. There were 201 patients who had RAAA postmortem (43%). Median age (range) was 73 (54-94) years in males and 77 (52-99) years in females, with a male-to-female ratio of 7:1. The peak incidence of RAAA was over 60 years of age in males and 70 years in females. Incidence of RAAA was 7.3/100,000/year in males and 5/100,000/year in females. For RAAA, 30-day perioperative mortality was 43% (105/243) while overall mortality was 70% (330/468), which includes deaths in the community. There was no improvement in 30-day mortality over time after comparing data for the first 7.5 years (50/115, 43.5%) with those for the second set of 7.5 years (55/128, 43%). There were 348 patients who had EAAA repair over the same period, comprising 282 males, with a male:female ratio of 4.3:1. The 30-day mortality in the elective group was 7.75%. Incidence and mortality of RAAA remain high. A high proportion of patients with AAA remain undiagnosed and die in the community. More lives may be saved if a screening program is started for AAA.     

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.     

Comparison of risk-scoring methods in predicting the immediate outcome after elective open abdominal aortic aneurysm surgery.

BACKGROUND & OBJECTIVES: The aim of this study was to apply three simple risk - scoring systems to prospectively collected data on all elective open Abdominal Aortic Aneurysm (AAA) operations in the Cambridge Academic Vascular Unit over a 6 - year period (January 1998 to January 2004), to compare their predictive values and to evaluate their validity with respect to prediction of mortality and post-operative complications. METHODS: 204 patients underwent elective open infra-renal AAA repair. Data were prospectively collected and risk assessment scores were calculated for mortality and morbidity according to the Glasgow Aneurysm Score (GAS), VBHOM (Vascular Biochemistry and Haematology Outcome Models) and Estimation of Physiologic Ability and Surgical Stress (E-PASS). RESULTS: The mortality rate was 6.3% (13/204) and 59% (121/204) experienced a post-operative complication (30-day outcome). For GAS, VBHOM and E-PASS the receiver operating characteristics (ROC) curve analysis for prediction of in-hospital mortality showed area under the curve (AUC) of 0.84 (95% confidence interval [CI], 0.76 to 0.92; p<0.0001), 0.82 (95% CI, 0.68 to 0.95; p=0.0001) and 0.92 (95% CI, 0.87 to 0.97; p<0.0001) respectively. There were also significant correlations between post-operative complications and length of hospital stay and each of the three scores, but the correlation was substantially higher in the case of E-PASS. CONCLUSIONS: All three scoring systems accurately predicted the risk of mortality and morbidity in patients undergoing elective open AAA repair. Among these, E-PASS seemed to be the most accurate predictor in this patient population.     

Abdominal aortic aneurysm screening in the United States

Abdominal aortic aneurysm (AAA) ruptures account for a high mortality rate in the United States. The Screen for Abdominal Aortic Aneurysm Very Efficiently (SAAAVE) Act in 2007 was implemented to prevent AAA ruptures and to benefit older US males using the Medicare system to initiate nationwide population-based AAA screening using United States Preventative Services Task Force screening criteria. After the first year of implementation, less than 1?% of all eligible Medicare beneficiaries were screened. A grassroots effort in 2009 sought to improve and modify the SAAAVE Act to include more Medicare enrollees through legislation. The largest integrated health systems, such as the Department of Veterans Affairs and Kaiser Permanente, use an electronic medical record to implement their own population-based AAA screening programs. Despite an underutilization of AAA screening across the US, efforts are underway into improving AAA screening programs and the management of small AAAs with clinical trials and prospective studies.     

A comparison of the mortality rate after elective repair of aortic aneurysms detected either by screening or incidentally.

OBJECTIVE: to compare predicted and actual mortality rates, using POSSUM scoring, after elective repair of abdominal aortic aneurysms (AAAs) detected from the Gloucestershire Aneurysm Screening Programme and those discovered incidentally. METHODS: a sample of 276 men undergoing elective AAA repair in Gloucestershire between 1991 and 1998 was studied. AAAs were either detected from the screening programme or were discovered incidentally and referred from other sources. Mortality data relating to these patients have been recorded prospectively. POSSUM scoring was performed retrospectively from patients> notes in both groups and related to outcome (30 day and in-hospital mortality). POSSUM and P-POSSUM methodology were used to compare observed and predicted mortality rates. RESULTS: in the 276 men who had elective AAA repair, the overall mortality rate was 7%. Mortality was lower in screen-detected AAAs (3/111, 3%) than AAAs discovered incidentally (16/175, 9%) (p=0.05). Preoperative physiology scores were significantly lower in men with a screen-detected AAA (median 19, range 13-29 versus 21, 12-41, p<0.001). POSSUM operative scores were similar between the groups. Actual versus predicted death ratios in the sample group were more accurate using POSSUM (ratio 0.93) than P-POSSUM (2.38) analysis. CONCLUSIONS: men with a screen-detected AAA had a lower mortality rate after elective repair than in those detected incidentally; lower preoperative physiology scores suggested they were fitter (as well as younger). In this study POSSUM analysis more accurately predicted outcome than P-POSSUM.     

Contemporary results of open repair of ruptured abdominal aortoiliac aneurysms: effect of surgeon volume on mortality

OBJECTIVE: The purpose of this study is to evaluate contemporary results of ruptured aortoiliac aneurysms (RAAA) and identify the role of surgeons' annual aortic volume and other prognostic indicators for early outcome. METHODS: A retrospective review identified 213 consecutive patients who presented with an atherosclerotic RAAA without thoracic extension over 6.5 years ending in June 2007. Excluded were 31 ruptures treated by endovascular repair (EVAR) or following previous EVAR, also excluded were two chronic asymptomatic hemodynamically stable ruptures. Ten patients were not treated due to either patient's refusal or prohibitive surgical risk. Demographic, preoperative, intraoperative, and postoperative variables were collected. Log rank test and Cox proportional hazard model analyses were utilized to identify factors contributing to mortality and morbidity in these patients. Survival rates were estimated by Kaplan-Meier method. RESULTS: One hundred thirty-one males and 39 females with a mean age of 74.5 +/- 8.1 years underwent consecutive RAAA repairs. The operative mortality rate was 38.2% (65/170), including 29 intraoperative deaths. Using multivariate analysis, surgeon's average annual AAA volume (<20/y), advanced age, and postoperative intestinal ischemia were independent predictors of perioperative deaths. Shock on presentation, preoperative cardiopulmonary resuscitation or free rupture were not. High-volume surgeons (>20 average annual AAA cases/y) had a higher 30-day survival rates (78.4% vs 57.9%, P = .024). Octogenarians had a lower 30-day survival rate of 49.0% vs 70.5% (P = .012). Patients who developed postoperative intestinal ischemia had a lower 30-day survival rate compared with patients without (48.1% vs 15.3%, P = .002). Increased intraoperative fluid and blood product usage was associated with bowel ischemia (P < .05). CONCLUSIONS: RAAA remains a highly lethal problem. The improved early outcomes of surgeons with high-volume AAA have strong implications for training, emergency staffing needs and alternative treatment strategies.     

Elective open operation for abdominal aortic aneurysm in octogenarians--survival analysis of 105 patients.

OBJECTIVES: To study early mortality and long-term survival of patients more than 80 years of age having elective open repair for abdominal aortic aneurysm (AAA). DESIGN: Retrospective multicenter cohort study. MATERIAL: One hundred and five patients, 23 women and 82 men, with a median age of 82 years, operated at three Norwegian hospitals during the period 1983-2002. METHOD: Survival analyses were based on data from medical records and the Norwegian Registrar's Office of Births and Deaths. Expected survival was based on mortality rates of the general population, matched by age, sex, and calendar period. Relative survival was calculated as the ratio between the observed and the expected survival. RESULTS: During the study period there has been a 10 fold increase in octogenarians treated with open operation for AAA. Early mortality (30-day) for the whole group of patients was 10.5% (95% confidence interval (95% CI) 5.3-18.0), and similar for both genders. The 5-year survival rate was 47% (95% CI 35.9-57.4), and not significantly different from that of a matched group in the general population. Patients aged 84 years or more had a median survival time of 35 months (95% CI 18.5-51.6). CONCLUSION: The number of AAA operations in octogenarians has increased considerably during 20 years. Octogenarians operated electively for AAA has higher 30-day mortality as compared to younger patients. Their long-term survival appears similar to a matched control group. The benefit of surgery must be carefully considered against the perioperative risk, especially for the oldest octogenarians.     

Fifteen-year follow-up of a randomized clinical trial of ultrasonographic screening for abdominal aortic aneurysms

BACKGROUND: Long-term benefits of screening for abdominal aortic aneurysm (AAA) are uncertain. These are the final results of a randomized controlled screening trial for AAA in men, updating those reported previously. Benefit and compliance over a median 15-year interval were examined. METHODS: One group of men were invited for ultrasonographic AAA screening, and another group, who received standard care, acted as controls. A total of 6040 men aged 65-80 years were randomized to one of the two groups. Outcome was monitored in terms of AAA-related events (surgery or death). RESULTS: In the group invited for screening, AAA-related mortality was reduced by 11 per cent (from 1.8 to 1.6 per cent, hazard ratio 0.89) over the follow-up interval. Screening detected an AAA in 170 patients; 17 of these died from an AAA-related cause, seven of which might have been preventable. The incidence of AAA rupture after an initially normal scan increased after 10 years of follow-up, but was still low overall (0.56 per 1000 person-years). CONCLUSION: Screening with a single ultrasonography scan still conferred a benefit at 15 years, although the results were not significant for this population size. Fewer than half of the AAA-related deaths in those screened positive could be prevented. Registration number: ISRCTN 00079388 (http://www.controlled-trials.com).     

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.     

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.