Screening for abdominal aortic aneurysms: single centre randomised con
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《英国医生杂志》
1 Vascular Research Unit, Department of Vascular Surgery, Sygehus Viborg, DK-8800 Viborg, Denmark, 2 Department of Epidemiology, Institute of Public Health, University of Aarhus, DK-8000 Aarhus C, Denmark
Correspondence to: J S Lindholt jes.s.lindholt@sygehusviborg.dk
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.
Ruptured abdominal aortic aneurysm occurs in about 1-3% of men aged 65 or more, 70-95% of whom die.1-4 Mortality in people undergoing elective surgery for abdominal aortic aneurysms is only 5-7%,1 but the condition seldom causes symptoms before rupture. Consequently, screening for such aneurysms is worth considering. A suitable and acceptable method of screening populations seems available.1 5-11 The psychological costs are limited12 13 because only 5% of people need rescanning every five years.14 The evidence base for treatment by size of aneurysm is clear.15 16 Abdominal aortic aneurysms may rupture during surveillance, however, and patients still die after surgery for a lesion that would never have ruptured if left untreated. Furthermore, surveillance decreases quality of life,12 17 more than 10% of patients have contraindications to surgery, and endovascular treatment does not remove the risk of rupture after initial treatment.18
These problems seem minor, however, if screening substantially reduces specific mortality. Consequently, we carried out a randomised controlled trial to determine whether screening Danish men aged 64-73 for abdominal aortic aneurysms reduces mortality.19
Materials and methods
In 1994 we randomised all men born during 1921-9 who lived in Viborg County, Denmark. To avoid delays between randomisation and screening, we randomised participants in blocks of about 1000. In 1995-8 we randomised all those who became 65. The mean age at randomisation was 67.7 years (range 64.3 to 73.8 years).
We randomly assigned the men to either screening (6333 participants) or the control group (6306). Participants in the screening group underwent abdominal ultrasonography at their regional hospital. Non-responders were reinvited once. Scanning (B mode) was carried out by a specially trained doctor and nurse using a Phillips SDR 1550 device with linear 4 MHz transducer and calliper light pen. Participants were not required to fast.
Baseline assessment and follow-up
We considered an abdominal aortic aneurysm to be present if the infrarenal aortic diameter was 3 cm. Participants with aneurysms 5 cm were referred to a vascular surgeon. The remaining participants with aneurysms were offered annual scans to check for expansion. They were referred for surgical evaluation if the aneurysm had expanded to 5 cm. After five years, men with an initial ectatic aorta (diameter 2.5-2.9 cm) were offered rescreening.14
Outcome measures
The primary outcome measures were specific mortality due to abdominal aortic aneurysm, total mortality, number of operations and indications for operations, and number of ruptured aneurysms. Data on operations were obtained from the patients' records.
We obtained data on deaths occurring from April 1994 to December 1999 through the Danish civil register and causes of death through the national register of causes of death. We obtained the hospital records and autopsy records of patients whose death certificates stated abdominal aortic aneurysm as the primary or contributing cause of death. The information was assessed by two vascular surgeons who were blinded to the randomisation group and to each other's evaluations. Each assessed the deaths to be certainly, possibly, or not caused by abdominal aortic aneurysm. We considered deaths to be due to abdominal aortic aneurysm when both assessors evaluated the death as certainly or possibly caused by such aneurysms.
Statistical analyses
We carried out analyses on an intention to screen basis from the date of randomisation. Fisher's exact test was used to compare proportions. We used Cox proportional hazards regression to compare specific mortality due to abdominal aortic aneurysm and overall mortality. As the proportional hazards assumption was not fulfilled, we decided to carry out separate analyses for the periods before and after 1.5 years after randomisation.
We calculated the expected number of life years gained within 5, 10, and 15 years for two hypothetical cohorts representing screened participants and controls, each of 6333 men aged 67. In the cohort representing the controls, we estimated the number of remaining life years from the life table for Danish men in 1995 and 1996. In the cohort representing the screened participants, we assumed the mortality for the period 1.5 to five years after randomisation to be reduced by the difference in specific mortality due to abdominal aortic aneurysm per 1000 years in the study (0.89, 95% confidence interval 0.40 to 1.37); before 1.5 years and after five years we assumed that the mortality was unaffected by screening. We selected this interval because evidence of a preventive effect was lacking until 1.5 years after randomisation. The observed age specific mortality among controls was close to Danish men in 1995 and 1996, but because we observed the controls for less than six years we could not use their data for projections beyond that. We carried out analyses using SPSS 10.0 and Stata 8.0.
Results
We randomised all 12 639 men aged 64-73 (mean age 67.7 years) living in Viborg County, Denmark (fig 1). They were followed up for a mean of 52 months (range < 0-69 months). The two groups were similar for duration of observation and age.
Fig 1 Flow of participants through trial
Overall, 4860 of 6333 participants allocated to the intervention group were screened by abdominal ultrasonography (attendance rate 76.6%, 95% confidence interval 75.6% to 77.7%). The anterior to posterior diameter of the aorta was successfully measured in 4816 of the 4860 attenders (99.3%), and an abdominal aortic aneurysm was detected in 191 (4.0%, 3.4% to 4.6%). Twenty four men (0.5%, 0.3% to 0.7%) with an aneurysm 5 cm were referred for surgery. During the five years after screening, a further 22 men were referred for elective surgery due to expansion of an aneurysm.
Operations and ruptures
The screened group underwent significantly fewer emergency procedures than the control group (75.0%, 50.9% to 91.3%; table 1).
Table 1 Relative risks associated with screening Danish men aged 64-73 for abdominal aortic aneurysms
Overall, 59 participants were operated on electively: 48 in the screened group and 11 in the control group. Of these, three (two in the screened group) died within 30 days postoperatively (5.1%). A fourth died 2.5 months postoperatively due to complications. Of those referred for surgery after screening, two died before surgery—one due to ruptured abdominal aortic aneurysm (surgery had to be postponed because of acute myocardial infarction) and the other due to ruptured iliac aneurysms. Furthermore, three participants with abdominal aortic aneurysms in the screened group who were recommended for surgery died of ruptured aneurysm; one initially had contraindications for surgery, one refused surgery, and one did not attend for follow-up.
Sixteen of the 37 patients with recognised rupture underwent surgery (43.2%), 10 of whom died (62.5%). Overall, the case fatality due to ruptured abdominal aortic aneurysm was 81.1% (64.8% to 92.0%), and the incidence of recognised ruptured aneurysms in the control group was 1.07 per 1000 observation years.
Mortality and survival
Nine participants in the screened group died from abdominal aortic aneurysm compared with 27 in the control group (hazard ratio 0.33, 0.16 to 0.71; fig 2). During the 18 months after randomisation, the two groups showed similar mortality due to abdominal aortic aneurysm (0.77, 0.29 to 2.07), but thereafter mortality was lower in the screened group (0.11, 0.03 to 0.48).
Fig 2 Kaplan-Meier estimates of mortality due to abdominal aortic aneurysm in Danish men aged 64-73 years. Difference between screened and control groups is P=0.003 (log rank test)
In the screened group, all cause mortality was insignificantly decreased (hazard ratio 0.92, 0.84 to 1.00; fig 3) and mortality from causes other than abdominal aortic aneurysm was also insignificantly decreased (0.92, 0.85 to 1.02).
Fig 3 Kaplan-Meier estimates of total mortality in Danish men aged 64-73 years screened for abdominal aortic aneurysm and controls. Difference between screened and control groups is P=0.053 (log rank test)
The number of life years gained by offering 6333 men screening was 32 (14 to 49) during the first five years (table 2). If the prediction was extended to 10 and 15 years, the number of life years gained was 107 (48 to 164) and 158 (71 to 244), respectively.
Table 2 Expected life years gained by inviting 6333 Danish men aged 64-73 to be screened for abdominal aortic aneurysm
Total mortality among non-attenders for screening was significantly higher than that among those who did attend for screening (hazard ratio 1.98, 1.73 to 2.26; fig 4).
Fig 4 Kaplan-Meier estimates of total mortality among attenders and non-attenders for screening for abdominal aortic aneurysm. Difference is P<0.001 (log rank test)
Discussion
Lindholt JS. Considerations and experiences of screening for abdominal aortic aneurysms. PhD thesis. Copenhagen, Denmark: FADL's Forlag, 1998.
Lindholt JS, Henneberg EW, Fasting H. Decreased mortality of abdominal aortic aneurysms in a peripheral county. Eur J Vasc Endovasc Surg 1995;10: 466-9.
Berridge DC, Chamberlain J, Guy AJ, Lambert D. Prospective audit of abdominal aortic aneurysm surgery in the northern region from 1988 to 1992. Northern Vascular Surgeons Group. Br J Surg 1995;82: 906-10.
Bengtsson H, Bergqvist D. Ruptured abdominal aortic aneurysms: a population-based study. J Vasc Surg 1993;18: 74-80.
Lindholt JS, Vammen S, Juul S, Henneberg EW, Fasting H. The validity of ultrasonographic scanning as screening method for abdominal aortic aneurysm. Eur J Vasc Endovasc Surg 1999;17: 472-5.
Lucarotti M, Shaw E, Poskitt K, Heather B. The Gloucestershire aneurysm screening programme: the first 2 years' experience. Eur J Vasc Surg 1993;7: 397-401.
Smith FC, Grimshaw GM, Paterson IS, Shearman CP, Hamer JD. Ultrasonographic screening for abdominal aortic aneurysm in an urban community. Br J Surg 1993;80: 1406-9.
Scott RA, Wilson NM, Ashton HA, Kay DN. Influence of screening on the incidence of ruptured abdominal aortic aneurysm: 5-year results of a randomized controlled study. Br J Surg 1995;82: 1066-70.
Morris GE, Hubbard CS, Quick CR. An abdominal aortic aneurysm screening programme for all males over the age of 50 years. Eur J Vasc Surg 1994;8: 156-60.
Lindholt JS, Juul S, Henneberg EW, Fasting H. Is screening for abdominal aortic aneurysm acceptable to the population? Selection and recruitment to hospital-based mass screening for abdominal aortic aneurysm. J Public Health Med 1998;20: 211-7.
Lindholt JS, Henneberg EW, Fasting H, Juul S. Mass or high-risk screening for abdominal aortic aneurysm. Br J Surg 1997;84: 40-2.
Lindholt JS, Vammen S, Fasting H, Henneberg EW. Psychological consequences of screening for abdominal aortic aneurysm and conservative treatment of small abdominal aortic aneurysms. Eur J Vasc Endovasc Surg 2000;20: 79-83.
MASS trial participants. Multicentre aneurysm screening study (MASS): cost effectiveness analysis of screening for abdominal aortic aneurysm based on four year results from randomised controlled trial. BMJ 2002;325: 1135-41.
Lindholt JS, Vammen S, Juul S, Fasting H, Henneberg EW. Optimal interval screening and surveillance of abdominal aortic aneurysms. Eur J Vasc Endovasc Surg 2000;20: 369-73.
UK Small Aneurysm Trial Participants. Mortality results for randomised controlled trial of early elective surgery or ultrasonographic surveillance for small abdominal aortic aneurysms. Lancet 1998;352: 1649-55.
Lederle FA, Wilson SE, Johnson GR, Reinke DB, Littooy FN, Acher CW, et al. Immediate repair compared with surveillance of small abdominal aortic aneurysms. N Engl J Med 2002;346: 1437-44.
UK Small Aneurysm Trial Participants. Health service costs and quality of life for early elective surgery or ultrasonographic surveillance for small abdominal aortic aneurysms. UK Small Aneurysm Trial Participants. Lancet 1998;352: 1656-60.
Harris PL, Vallabhaneni SR, Desgranges P, Becquemin JP, van Marrewijk C, Laheij RJ. Incidence and risk factors of late rupture, conversion, and death after endovascular repair of infrarenal aortic aneurysms: the EUROSTAR experience. European Collaborators on Stent/graft techniques for aortic aneurysm repair. J Vasc Surg 2000;32: 739-49.
Lindholt JS, Henneberg EW, Fasting H, Juul S. Hospital based screening of 65-73 year old men for abdominal aortic aneurysms in the county of Viborg, Denmark. J Med Screen 1996;3: 43-6.
Rembold CM. Number needed to screen: development of a statistic for disease screening. BMJ 1998;317: 307-12.
Lindholt JS, Juul S, Fasting H, Henneberg EW. Hospital costs and benefits of screening for abdominal aortic aneurysms. Results from a randomised population screening trial. Eur J Vasc Endovasc Surg 2002;23: 55-60.
Ashton HA, Buxton MJ, Day NE, Kim LG, Marteau TM, Scott RA, et al. The multicentre aneurysm screening study (MASS) into the effect of abdominal aortic aneurysm screening on mortality in men: a randomised controlled trial. Lancet 2002;360: 1531-9.
Norman PE, Jamrozik K, Lawrence-Brown MM, Le MTQ, Spencer CA, Tuohy RJ, et al. Population based randomised controlled trial on impact of screening on mortality from abdominal aortic aneurysm. BMJ 2004;329: 1259-62.(Jes S Lindholt, senior lecturer1, Svend )
Correspondence to: J S Lindholt jes.s.lindholt@sygehusviborg.dk
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.
Ruptured abdominal aortic aneurysm occurs in about 1-3% of men aged 65 or more, 70-95% of whom die.1-4 Mortality in people undergoing elective surgery for abdominal aortic aneurysms is only 5-7%,1 but the condition seldom causes symptoms before rupture. Consequently, screening for such aneurysms is worth considering. A suitable and acceptable method of screening populations seems available.1 5-11 The psychological costs are limited12 13 because only 5% of people need rescanning every five years.14 The evidence base for treatment by size of aneurysm is clear.15 16 Abdominal aortic aneurysms may rupture during surveillance, however, and patients still die after surgery for a lesion that would never have ruptured if left untreated. Furthermore, surveillance decreases quality of life,12 17 more than 10% of patients have contraindications to surgery, and endovascular treatment does not remove the risk of rupture after initial treatment.18
These problems seem minor, however, if screening substantially reduces specific mortality. Consequently, we carried out a randomised controlled trial to determine whether screening Danish men aged 64-73 for abdominal aortic aneurysms reduces mortality.19
Materials and methods
In 1994 we randomised all men born during 1921-9 who lived in Viborg County, Denmark. To avoid delays between randomisation and screening, we randomised participants in blocks of about 1000. In 1995-8 we randomised all those who became 65. The mean age at randomisation was 67.7 years (range 64.3 to 73.8 years).
We randomly assigned the men to either screening (6333 participants) or the control group (6306). Participants in the screening group underwent abdominal ultrasonography at their regional hospital. Non-responders were reinvited once. Scanning (B mode) was carried out by a specially trained doctor and nurse using a Phillips SDR 1550 device with linear 4 MHz transducer and calliper light pen. Participants were not required to fast.
Baseline assessment and follow-up
We considered an abdominal aortic aneurysm to be present if the infrarenal aortic diameter was 3 cm. Participants with aneurysms 5 cm were referred to a vascular surgeon. The remaining participants with aneurysms were offered annual scans to check for expansion. They were referred for surgical evaluation if the aneurysm had expanded to 5 cm. After five years, men with an initial ectatic aorta (diameter 2.5-2.9 cm) were offered rescreening.14
Outcome measures
The primary outcome measures were specific mortality due to abdominal aortic aneurysm, total mortality, number of operations and indications for operations, and number of ruptured aneurysms. Data on operations were obtained from the patients' records.
We obtained data on deaths occurring from April 1994 to December 1999 through the Danish civil register and causes of death through the national register of causes of death. We obtained the hospital records and autopsy records of patients whose death certificates stated abdominal aortic aneurysm as the primary or contributing cause of death. The information was assessed by two vascular surgeons who were blinded to the randomisation group and to each other's evaluations. Each assessed the deaths to be certainly, possibly, or not caused by abdominal aortic aneurysm. We considered deaths to be due to abdominal aortic aneurysm when both assessors evaluated the death as certainly or possibly caused by such aneurysms.
Statistical analyses
We carried out analyses on an intention to screen basis from the date of randomisation. Fisher's exact test was used to compare proportions. We used Cox proportional hazards regression to compare specific mortality due to abdominal aortic aneurysm and overall mortality. As the proportional hazards assumption was not fulfilled, we decided to carry out separate analyses for the periods before and after 1.5 years after randomisation.
We calculated the expected number of life years gained within 5, 10, and 15 years for two hypothetical cohorts representing screened participants and controls, each of 6333 men aged 67. In the cohort representing the controls, we estimated the number of remaining life years from the life table for Danish men in 1995 and 1996. In the cohort representing the screened participants, we assumed the mortality for the period 1.5 to five years after randomisation to be reduced by the difference in specific mortality due to abdominal aortic aneurysm per 1000 years in the study (0.89, 95% confidence interval 0.40 to 1.37); before 1.5 years and after five years we assumed that the mortality was unaffected by screening. We selected this interval because evidence of a preventive effect was lacking until 1.5 years after randomisation. The observed age specific mortality among controls was close to Danish men in 1995 and 1996, but because we observed the controls for less than six years we could not use their data for projections beyond that. We carried out analyses using SPSS 10.0 and Stata 8.0.
Results
We randomised all 12 639 men aged 64-73 (mean age 67.7 years) living in Viborg County, Denmark (fig 1). They were followed up for a mean of 52 months (range < 0-69 months). The two groups were similar for duration of observation and age.
Fig 1 Flow of participants through trial
Overall, 4860 of 6333 participants allocated to the intervention group were screened by abdominal ultrasonography (attendance rate 76.6%, 95% confidence interval 75.6% to 77.7%). The anterior to posterior diameter of the aorta was successfully measured in 4816 of the 4860 attenders (99.3%), and an abdominal aortic aneurysm was detected in 191 (4.0%, 3.4% to 4.6%). Twenty four men (0.5%, 0.3% to 0.7%) with an aneurysm 5 cm were referred for surgery. During the five years after screening, a further 22 men were referred for elective surgery due to expansion of an aneurysm.
Operations and ruptures
The screened group underwent significantly fewer emergency procedures than the control group (75.0%, 50.9% to 91.3%; table 1).
Table 1 Relative risks associated with screening Danish men aged 64-73 for abdominal aortic aneurysms
Overall, 59 participants were operated on electively: 48 in the screened group and 11 in the control group. Of these, three (two in the screened group) died within 30 days postoperatively (5.1%). A fourth died 2.5 months postoperatively due to complications. Of those referred for surgery after screening, two died before surgery—one due to ruptured abdominal aortic aneurysm (surgery had to be postponed because of acute myocardial infarction) and the other due to ruptured iliac aneurysms. Furthermore, three participants with abdominal aortic aneurysms in the screened group who were recommended for surgery died of ruptured aneurysm; one initially had contraindications for surgery, one refused surgery, and one did not attend for follow-up.
Sixteen of the 37 patients with recognised rupture underwent surgery (43.2%), 10 of whom died (62.5%). Overall, the case fatality due to ruptured abdominal aortic aneurysm was 81.1% (64.8% to 92.0%), and the incidence of recognised ruptured aneurysms in the control group was 1.07 per 1000 observation years.
Mortality and survival
Nine participants in the screened group died from abdominal aortic aneurysm compared with 27 in the control group (hazard ratio 0.33, 0.16 to 0.71; fig 2). During the 18 months after randomisation, the two groups showed similar mortality due to abdominal aortic aneurysm (0.77, 0.29 to 2.07), but thereafter mortality was lower in the screened group (0.11, 0.03 to 0.48).
Fig 2 Kaplan-Meier estimates of mortality due to abdominal aortic aneurysm in Danish men aged 64-73 years. Difference between screened and control groups is P=0.003 (log rank test)
In the screened group, all cause mortality was insignificantly decreased (hazard ratio 0.92, 0.84 to 1.00; fig 3) and mortality from causes other than abdominal aortic aneurysm was also insignificantly decreased (0.92, 0.85 to 1.02).
Fig 3 Kaplan-Meier estimates of total mortality in Danish men aged 64-73 years screened for abdominal aortic aneurysm and controls. Difference between screened and control groups is P=0.053 (log rank test)
The number of life years gained by offering 6333 men screening was 32 (14 to 49) during the first five years (table 2). If the prediction was extended to 10 and 15 years, the number of life years gained was 107 (48 to 164) and 158 (71 to 244), respectively.
Table 2 Expected life years gained by inviting 6333 Danish men aged 64-73 to be screened for abdominal aortic aneurysm
Total mortality among non-attenders for screening was significantly higher than that among those who did attend for screening (hazard ratio 1.98, 1.73 to 2.26; fig 4).
Fig 4 Kaplan-Meier estimates of total mortality among attenders and non-attenders for screening for abdominal aortic aneurysm. Difference is P<0.001 (log rank test)
Discussion
Lindholt JS. Considerations and experiences of screening for abdominal aortic aneurysms. PhD thesis. Copenhagen, Denmark: FADL's Forlag, 1998.
Lindholt JS, Henneberg EW, Fasting H. Decreased mortality of abdominal aortic aneurysms in a peripheral county. Eur J Vasc Endovasc Surg 1995;10: 466-9.
Berridge DC, Chamberlain J, Guy AJ, Lambert D. Prospective audit of abdominal aortic aneurysm surgery in the northern region from 1988 to 1992. Northern Vascular Surgeons Group. Br J Surg 1995;82: 906-10.
Bengtsson H, Bergqvist D. Ruptured abdominal aortic aneurysms: a population-based study. J Vasc Surg 1993;18: 74-80.
Lindholt JS, Vammen S, Juul S, Henneberg EW, Fasting H. The validity of ultrasonographic scanning as screening method for abdominal aortic aneurysm. Eur J Vasc Endovasc Surg 1999;17: 472-5.
Lucarotti M, Shaw E, Poskitt K, Heather B. The Gloucestershire aneurysm screening programme: the first 2 years' experience. Eur J Vasc Surg 1993;7: 397-401.
Smith FC, Grimshaw GM, Paterson IS, Shearman CP, Hamer JD. Ultrasonographic screening for abdominal aortic aneurysm in an urban community. Br J Surg 1993;80: 1406-9.
Scott RA, Wilson NM, Ashton HA, Kay DN. Influence of screening on the incidence of ruptured abdominal aortic aneurysm: 5-year results of a randomized controlled study. Br J Surg 1995;82: 1066-70.
Morris GE, Hubbard CS, Quick CR. An abdominal aortic aneurysm screening programme for all males over the age of 50 years. Eur J Vasc Surg 1994;8: 156-60.
Lindholt JS, Juul S, Henneberg EW, Fasting H. Is screening for abdominal aortic aneurysm acceptable to the population? Selection and recruitment to hospital-based mass screening for abdominal aortic aneurysm. J Public Health Med 1998;20: 211-7.
Lindholt JS, Henneberg EW, Fasting H, Juul S. Mass or high-risk screening for abdominal aortic aneurysm. Br J Surg 1997;84: 40-2.
Lindholt JS, Vammen S, Fasting H, Henneberg EW. Psychological consequences of screening for abdominal aortic aneurysm and conservative treatment of small abdominal aortic aneurysms. Eur J Vasc Endovasc Surg 2000;20: 79-83.
MASS trial participants. Multicentre aneurysm screening study (MASS): cost effectiveness analysis of screening for abdominal aortic aneurysm based on four year results from randomised controlled trial. BMJ 2002;325: 1135-41.
Lindholt JS, Vammen S, Juul S, Fasting H, Henneberg EW. Optimal interval screening and surveillance of abdominal aortic aneurysms. Eur J Vasc Endovasc Surg 2000;20: 369-73.
UK Small Aneurysm Trial Participants. Mortality results for randomised controlled trial of early elective surgery or ultrasonographic surveillance for small abdominal aortic aneurysms. Lancet 1998;352: 1649-55.
Lederle FA, Wilson SE, Johnson GR, Reinke DB, Littooy FN, Acher CW, et al. Immediate repair compared with surveillance of small abdominal aortic aneurysms. N Engl J Med 2002;346: 1437-44.
UK Small Aneurysm Trial Participants. Health service costs and quality of life for early elective surgery or ultrasonographic surveillance for small abdominal aortic aneurysms. UK Small Aneurysm Trial Participants. Lancet 1998;352: 1656-60.
Harris PL, Vallabhaneni SR, Desgranges P, Becquemin JP, van Marrewijk C, Laheij RJ. Incidence and risk factors of late rupture, conversion, and death after endovascular repair of infrarenal aortic aneurysms: the EUROSTAR experience. European Collaborators on Stent/graft techniques for aortic aneurysm repair. J Vasc Surg 2000;32: 739-49.
Lindholt JS, Henneberg EW, Fasting H, Juul S. Hospital based screening of 65-73 year old men for abdominal aortic aneurysms in the county of Viborg, Denmark. J Med Screen 1996;3: 43-6.
Rembold CM. Number needed to screen: development of a statistic for disease screening. BMJ 1998;317: 307-12.
Lindholt JS, Juul S, Fasting H, Henneberg EW. Hospital costs and benefits of screening for abdominal aortic aneurysms. Results from a randomised population screening trial. Eur J Vasc Endovasc Surg 2002;23: 55-60.
Ashton HA, Buxton MJ, Day NE, Kim LG, Marteau TM, Scott RA, et al. The multicentre aneurysm screening study (MASS) into the effect of abdominal aortic aneurysm screening on mortality in men: a randomised controlled trial. Lancet 2002;360: 1531-9.
Norman PE, Jamrozik K, Lawrence-Brown MM, Le MTQ, Spencer CA, Tuohy RJ, et al. Population based randomised controlled trial on impact of screening on mortality from abdominal aortic aneurysm. BMJ 2004;329: 1259-62.(Jes S Lindholt, senior lecturer1, Svend )