Screening for Abdominal Aortic Aneurysm: US Preventive Services Task Force Recommendation Statement. Selective screening for abdominal aortic aneurysms with physical examination and ultrasound. 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. [Preliminary results of screening for abdominal aortic aneurysm in the ounty of Viborg]. Screening for abdominal aortic aneurysms in men: a Canadian perspective using Monte Carlo-based estimates. A Sustained Mortality Benefit from Screening for Abdominal Aortic Aneurysm Hospital costs and benefits of screening for abdominal aortic aneurysms. Results from a randomised population screening trial. Abdominal Aortic Aneurysm (Aaa): Cost-Effectiveness of Screening, Surveillance of Intermediate-Sized Aaa, and Management of Symptomatic Aaa
Importance An abdominal aortic aneurysm ( AAA ) is typically defined as aortic enlargement with a diameter of 3.0 cm or larger . The prevalence of AAA has declined over the past 2 decades among screened men 65 years or older in various European countries . The current prevalence of AAA in the United States is unclear because of the low uptake of screening . Most AAAs are asymptomatic until they rupture . Although the risk for rupture varies greatly by aneurysm size , the associated risk for death with rupture is as high as 81 % . Objective To up date its 2014 recommendation , the USPSTF commissioned a review of the evidence on the effectiveness of 1-time and repeated screening for AAA , the associated harms of screening , and the benefits and harms of available treatments for small AAAs ( 3.0 - 5.4 cm in diameter ) identified through screening . Population This recommendation applies to asymptomatic adults 50 years or older . However , the r and omized trial evidence focuses almost entirely on men aged 65 to 75 years . Evidence Assessment Based on a review of the evidence , the USPSTF concludes with moderate certainty that screening for AAA in men aged 65 to 75 years who have ever smoked is of moderate net benefit . The USPSTF concludes with moderate certainty that screening for AAA in men aged 65 to 75 years who have never smoked is of small net benefit . The USPSTF concludes that the evidence is insufficient to determine the net benefit of screening for AAA in women aged 65 to 75 years who have ever smoked or have a family history of AAA . The USPSTF concludes with moderate certainty that the harms of screening for AAA in women aged 65 to 75 years who have never smoked and have no family history of AAA outweigh the benefits . Recommendations The USPSTF recommends 1-time screening for AAA with ultrasonography in men aged 65 to 75 years who have ever smoked . ( B recommendation ) The USPSTF recommends that clinicians selectively offer screening for AAA with ultrasonography in men aged 65 to 75 years who have never smoked rather than routinely screening all men in this group . ( C recommendation ) The USPSTF recommends against routine screening for  AAA  with ultrasonography in women who have never smoked and have no family history of AAA . ( D recommendation ) The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for AAA with ultrasonography in women aged 65 to 75 years who have ever smoked or have a family history of AAA . ( I statement ) Abdominal aortic aneurysm ( AAA ) is an important cause of preventable death in older persons . Persistently high rupture mortality rates indicate that these deaths can be prevented only by early detection and treatment of AAA . In an effort to develop an effective and efficient program of AAA detection , we selectively screened a high-risk population . Men aged 60 to 75 years with hypertension and /or coronary artery disease were r and omly selected from a general medicine clinic and screened with physical examination and ultrasound . Eighteen previously unsuspected aneurysms , 3.6 to 5.9 cm in size ( mean , 4.4 cm ) , were detected in 201 patients , for a prevalence of 9 % ( 95 % confidence interval : 4.7 % to 13.3 % ) . The specificity and positive predictive value of ultrasound were each 100 % . Abdominal palpation detected only half of these aneurysms , but missed none in patients with an abdominal girth less than 100 cm ( n = 6 ) . This degree of sensitivity did not occur with " routine " examinations and requires that the examination be directed specifically toward AAA detection . We conclude that undiagnosed AAAs are common in this large subgroup of the clinic population , that ultrasound is an excellent screening test for AAAs , and that physical examination may be adequate for screening thin patients . We recommend that every two or three years persons over the age of 50 years undergo careful abdominal palpation aim ed at detecting AAAs , as part of the periodic health examination . We further recommend that obese older men at high risk for AAA have at least one-time screening with abdominal ultrasound , regardless of findings on physical examination 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 r and omisation 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 The incidence of abdominal aortic aneurysms ( AAA ) and ruptured AAA is increasing . One to three percent of deaths among 65 - 80 year-old males are caused by AAA . Sixty-six to ninety-five percent of ruptured AAA are lethal , while elective resection has a 3 - 6 % operative mortality . Most AAA 's are asymptomatic before rupture . Ultrasonographic scanning of the aorta takes below ten minutes with close to 100 % sensitivity and specificity . The County of Viborg has started a r and omized screening trial including 13,500 65 - 73 year-old males . Half of these are invited to the nearest hospital over a period of three years . In 1994 - 1995 4938 were invited and 3748 were scanned , result ing in an  acceptance rate  of 76 % . The aorta was visible in 99.7 % , and the total time consumption was 9.7 minutes per scan . The costs were 83.75 DKK per scan . One hundred and fifty-three ( 4.1 % ) had an AAA defined as an aortic diameter above 29 mm . Twenty were above 49 mm and were offered operation , i.e. 5.3 per thous and scans or 13 % of the diagnosed AAA OBJECTIVE Recently generated r and omized screening trial data have provided good evidence in favour of routine screening for abdominal aortic aneurysm ( AAA ) to reduce AAA-related deaths in men aged 65 years and older . We developed an economic model that assessed the incremental cost-utility of AAA screening to help decision makers judge the relevance of a national screening program in Canada . METHODS We constructed a 14 health state Markov model comparing 2 cohorts of 65-year-old men , where the first cohort was invited to attend screening for AAA using ultrasonography ( US )  and the second cohort followed the current practice of opportunistic detection . Lifetime outcomes included the life-years gained , AAA rupture avoided , AAA-related mortality , quality -adjusted life years ( QALYs ) and costs . Transition probabilities were derived from a systematic review of the literature , and a probabilistic sensitivity analysis was carried out to examine the effect of joint uncertainty in the variables of our analysis . The perspective adopted was that of the health care provider . RESULTS Invitations to attend screening produced an undiscounted gain in life expectancy of 0.049 years and a gain in discounted QALY of 0.019 for an estimated incremental lifetime cost of CAN$118 . The estimated incremental cost-utility ratio was CAN$6194 per QALY gained ( 95 % confidence interval [ CI ] 1892 - 10 837 ) . The numbers needed to invite to attend screening , and the numbers needed to screen to prevent 1 AAA-related death were 187 ( 95 % CI 130 - 292 ) and 137 ( 95 % CI 85 - 213 ) , respectively . The acceptability curve showed a greater than 95 % probability of the program 's being cost-effective , and the model was robust to changes in the values of key parameters within plausible ranges . CONCLUSION Our results support the economic viability of a national screening program for men reaching 65 years of age in Canada . More clinical studies are needed to define the role of screening in subgroups at high risk , especially in the female population Context Is it cost-effective to screen older adults for abdominal aortic aneurysm ( AAA ) ? Contribution This 7-year follow-up report of a large r and omized trial in the United Kingdom found that men age 65 to 74 years who were invited to have ultrasonography and surveillance for AAA  had lower mortality rates than did those who were not invited ( hazard ratio , 0.53 [ CI , 0.42 to 0.68 ] ) . Cost-effectiveness for AAA-related deaths , based on costs applied to the events experienced by the men , was estimated at $ 19500 ( CI , $ 12400 to $ 39800 ) per life-year gained . Caution s Only men were studied .  Actual costs of screening and surveillance  may vary substantially in different setting s. The Editors A fast-growing body of literature is providing evidence in favor of screening men for abdominal aortic aneurysm ( AAA ) . Several large , r and omized trials published in the past few years ( 14 ) have consistently shown that screening reduces AAA-related mortality . A few observational studies of programs under way in localized areas have established the feasibility of systematic screening and have explored its practical implementation ( 57 ) . In addition to the mortality benefit , evidence indicating that screening is highly cost-effective is increasing ( 811 ) . In light of this evidence , national screening programs are now being considered in many countries ( 1214 ) . However , there is little evidence regarding long-term outcomes after AAA screening ; almost all of the evidence from r and omized trials is limited to the first 4 years after screening ( 14 ) . Moreover , long-term cost-effectiveness has been estimated only through health economic modeling ( 10 ) . We describe cost-effectiveness based on 7-year follow-up from the largest of the 4 trials of AAA screeningthe Multicentre Aneurysm Screening Study ( MASS ) ( 2 ) . The trial r and omly assigned approximately 67800 men age 65 to 74 years to receive an invitation to screening or to not receive an invitation .  At 4-year follow-up , the trial reported a substantial relative reduction of 42 % ( 95 % CI , 22 % to 58 % ) in AAA-related mortality and an incremental cost-effectiveness ratio of $ 44900 ( CI , $ 24000 to $ 231000 ) per life-year gained ( 9 ) , which is at the borderline of the commonly accepted threshold for interventions . All values are reported in U.S. dollars ( U.K. 1 = U.S. $ 1.58 ) ( 15 ) . The costs of AAA screening are primarily incurred at the start of the program , but benefits continue to accrue in terms of life-years gained in patients in whom AAA rupture is avoided through elective surgery . It is therefore expected that cost-effectiveness of screening will improve over time . The mid-term results of MASS provide reliable , trial-based information regarding clinical outcomes and cost-effectiveness over a longer period . Methods The details of the MASS protocol were described previously ( 2 ) , but a brief summary is provided ( Figure 1 ) . Between 1997 and 1999 , a population -based sample of 70495 men age 65 to 74 years from 4 centers in the United Kingdom was identified by obtaining records for every man in this age range who was registered with a family physician ( registered persons account for approximately 98 % of the population ) . Persons who were ineligible for the trial ( incorrect details , known AAA , previous AAA surgery , or terminal illness ) were excluded before r and omization . The remaining 67770 men were r and omly assigned to receive an invitation to ultrasonography for AAA or to not receive an invitation to ultrasonography . At screening , men with an aortic diameter of 3.0 cm or greater were defined as having an AAA and were subsequently invited for recall scans to monitor growth of the aneurysm . Men with an aortic diameter of 3.0 to 4.4 cm were rescreened every year , and those with an aortic diameter of 4.5 to 5.4 cm were rescreened every 3 months . Participants were considered for elective surgery when the aortic diameter reached 5.5 cm , aortic expansion was 1.0 cm or more in 1 year , or they experienced symptoms attributable to the aneurysm . Men with an aortic diameter less than 3.0 cm on the initial scan were not rescreened . Blood pressure was also measured ; although family physicians were informed of these measurements , no further intervention was provided through the screening program . We obtained approval from local ethics committees at each center , and all patients who had screening provided signed informed consent . Figure 1 . Study flow diagram . Additional data on follow-up scans and AAA surgeries were collected from hospital records . Deaths up to 31 March 2005 were confirmed by the U.K. Office of National Statistics after matching of the unique National Health Service number for each person . Follow-up ranged from 5.9 to 8.2 years ( mean , 7.1 years ) . The primary outcome of interest , AAA-related mortality , is defined as all deaths within 30 days of any AAA surgery ( elective or emergency ) plus all deaths with International Classification of Diseases , Ninth Revision , codes 441.3 ( ruptured abdominal aortic aneurysm ) , 441.4 ( abdominal aortic aneurysm without mention of rupture ) , 441.5 ( ruptured aortic aneurysm at unspecified site ) , or 441.6 ( aortic aneurysm at unspecified site without mention of rupture ) . The use of codes 441.5 and 441.6 may result in inclusion of some thoracic aortic aneurysm deaths . Investigation of the accuracy of cause-of-death coding on the death certificates was done by an independent mortality working party that was blinded to group allocation . The results of this analysis showed that inaccuracies in coding did not have an important impact on study outcomes ( 2 ) . Statistical Analysis All analyses were done by using Stata , version 9 ( Stata Corp. , College Station , Texas ) . Deaths related to AAA ( primary analysis ) and all-cause mortality ( secondary analysis ) were compared between the 2 r and omized groups by using unadjusted Cox regression by intention-to-treat analysis . Adjustment for age at baseline did not influence the results . The proportional hazards assumption was tested by using Schoenfeld residuals . An unbiased r and omization-based estimate of the benefit of  screening  was also obtained ( 16 ) . This estimate is calculated by subtracting from the control group a subgroup that is equivalent in terms of survival to the nonadherent subgroup in the invited group . Thus , the remaining controls are comparable to the group of invited patients who attended screening . Life-years gained are estimated as the area between the KaplanMeier curves for both groups ( 17 ) . The cost-effectiveness of screening  is estimated from a health service perspective for follow-up truncated at 7 years , with adjustment for censoring ( 18 ) . Details of the costing exercise in the trial at 20002001 prices were reported previously ( 9 ) . The unit costs obtained ( U.K. 1 = U.S. $ 1.58 for the year 2000 [ 15 ] ) are inflated to the 20042005 financial-year level by using annual hospital and community health services pay and price inflation indices ( 19 ) . Costs are applied to the following events on the basis of individual re source use : invitation to screening ( $ 2.46 ) , reinvitation after nonresponse ( $ 2.42 ) , initial scan ( $ 35.95 ) , recall scan ( $ 86.74 ; done in the hospital rather than in the community and including costs for periodic routine meetings with a consultant ) , consultation for elective surgery ( $ 583.79 ) , elective AAA surgery ( $ 13015.74 ) , and emergency AAA surgery ( $ 21054.32 ) . Costs relating to scans of incidentally detected AAAs in the control group are not included ( data not available ) , but costs relating from result ant AAA repair surgery are included . Sensitivity analyses were done by using 1 ) costs retained at the 20002001 financial-year level for comparison with previous publications , 2 ) quality -adjusted life-years based on age-related reductions , 3 ) U.S.-based unit cost estimates for scans and surgeries , 4 ) an increase of 50 % in the cost of a consultation  ( a U.S.-based estimate was not available , but this analysis reflects possible additional assessment s ) , 5 ) 3 and 4 combined . Quality -of-life adjustments are made only on the basis of age , with an adjustment of 0.78 for life-years gained between the ages 65 and 74 years and an adjustment of 0.75 for life-years gained at ages older than 75 years ( 20 ) . The U.S.-specific estimates for scans ( initial and recall ) are based on Medicare reimbursement for AAA screening at $ 90.95 ( Current Procedural Terminology code G0389 ) ( 21 ) , and U.S.-specific costs for surgeries are based on previously published estimates ( 22 , 23 ) that were inflated to 2004 prices ( 24 ) : $ 18160 for elective procedures and $ 31106 for emergency procedures . Discounting is applied at the current recommended values of 3 % per annum for costs and effects ( 25 ) . Estimates of AAA-related costs and effects take into account the rate of nonAAA-related deaths across both groups over time . The Fieller method is used to calculate bounds for the CI for cost-effectiveness ( 26 , 27 ) . Role of the Funding Source This study was funded by the Medical Research Council . The funding source had no role in the design , implementation , or analysis of the study . Results Figure 1 shows the flow of participants through the trial . Numbers differ slightly from earlier publications because of identification of a few duplicate records in the data base . Of 67770 r and omly assigned men , 33883 were invited to be screened : 27204 ( 80 % ) attended and 1334 ( 4.9 % ) AAAs were identified . The mean age at r and omization was 69.2 years in both groups . Loss to follow-up because of death was 2.1 % overall ( 2.2 % in the control group and 2.1 % in the invited group ) . Loss to clinical follow-up ( nonattendance at recall scans ) was 19 % at 4 years and 24 % at 7 years . The Appendix Table shows surgeries and deaths within 30 days in each of the r and omly assigned groups . A few endovascular operations are included in these figures6 in the control group and 14 in the invited group . As expected , the total number of elective procedures is greater in the invited group than in the control group OBJECTIVES to analyse the hospital costs and benefits of screening  older males for abdominal aortic aneurysm ( AAA ) . MATERIAL S 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 research ed . 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 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 r and omized 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 ( = 5.5 cm ) . Two recent r and omized 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
Electronic reminders are a simple EMR addition that can provide evidence -based education while improving adherence rates with preventive health screening measures
Abstract : The 2014 United States Preventive Services Task Force systematic review found abdominal aortic aneurysm ( AAA ) screening decreased related mortality by close to half .
Despite the simplicity of screening , research suggests poor adherence to the recommended AAA screening guidelines .