1、Screening for Abdominal Aortic Aneurysm: U.S. Preventive ServicesTask Force Recommendation StatementMichael L. LeFevre, MD, MSPH, on behalf of the U.S. Preventive Services Task Force*Description: Update of the 2005 U.S. Preventive Services TaskForce (USPSTF) recommendation on screening for abdominal
2、 aorticaneurysm (AAA).Methods: The USPSTF commissioned a systematic review that as-sessed the evidence on the benefits and harms of screening forAAA and strategies for managing small (3.0 to 5.4 cm) screen-detected AAAs.Population: These recommendations apply to asymptomatic adultsaged 50 years or o
3、lder.Recommendation: The USPSTF recommends 1-time screening forAAA with ultrasonography in men aged 65 to 75 years who haveever smoked. (B recommendation)The USPSTF recommends that clinicians selectively offer screen-ing for AAA in men aged 65 to 75 years who have never smoked.(C recommendation)The
4、USPSTF concludes that the current evidence is insufficient toassess the balance of benefits and harms of screening for AAA inwomen aged 65 to 75 years who have ever smoked. (I statement)The USPSTF recommends against routine screening for AAA inwomen who have never smoked. (D recommendation)Ann Inter
5、n Med. doi:10.7326/M14-1204www.annals.orgFor author affiliation, see end of text.* For a list of USPSTF members, see the Appendix (available at www.annals.org).This article was published online first at www.annals.org on 24 June 2014.The U.S. Preventive Services Task Force (USPSTF) makesrecommendati
6、ons about the effectiveness of specific preven-tive care services for patients without related signs orsymptoms.It bases its recommendations on the evidence of both thebenefits and harms of the service and an assessment of thebalance. The USPSTF does not consider the costs of providinga service in t
7、his assessment.The USPSTF recognizes that clinical decisions involvemore considerations than evidence alone. Clinicians shouldunderstand the evidence but individualize decision making tothe specific patient or situation. Similarly, the USPSTF notesthat policy and coverage decisions involve considera
8、tions inaddition to the evidence of clinical benefits and harms.SUMMARY OFRECOMMENDATION ANDEVIDENCEThe USPSTF recommends 1-time screening for ab-dominal aortic aneurysm (AAA) with ultrasonography inmen aged 65 to 75 years who have ever smoked. (Brecommendation)The USPSTF recommends that clinicians
9、selectivelyoffer screening for AAA in men aged 65 to 75 years whohave never smoked rather than routinely screening all menin this group. Evidence indicates that the net benefit ofscreening all men aged 65 to 75 years who have neversmoked is small. In determining whether this service isappropriate in
10、 individual cases, patients and cliniciansshould consider the balance of benefits and harms on thebasis of evidence relevant to the patients medical history,family history, other risk factors, and personal values. (Crecommendation)See the Clinical Considerations section for additionalinformation on
11、risk assessment.The USPSTF concludes that the current evidence isinsufficient to assess the balance of benefits and harms ofscreening for AAA in women aged 65 to 75 years who haveever smoked. (I statement)See the Clinical Considerations section for suggestionsfor practice regarding the I statement.T
12、he USPSTF recommends against routine screeningforAAAinwomenwhohaveneversmoked.(Drecommendation)These recommendations apply to asymptomatic adultsaged 50 years or older.For the purposes of this recommendation, an “ever-smoker” is a person who has smoked at least 100 cigarettesin his or her lifetime.S
13、ee the Figure for a summary of the recommendationand suggestions for clinical practice.See also:Related article. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Summary for Patients. . . . . . . . . . . . . . . . . . . . . . . . . 2Web-OnlyCME quizThisonline-firstversionwillbereplacedwi
14、thafinalversionwhenitisincludedintheissue.Thefinalversionmaydifferinsmallways.Annals of Internal MedicineClinical Guidelinewww.annals.orgAnnals of Internal Medicine1Annals of Internal MedicineDownloaded From: http:/annals.org/ on 06/24/Appendix Table 1 describes the USPSTF grades, andAppendix Table
15、2 describes the USPSTF classification oflevels of certainty about net benefit (both tables are avail-able at www.annals.org).RATIONALEImportanceAbdominal aortic aneurysms are typically defined byan aortic diameter of 3.0 cm or larger. Population-basedstudies in adults older than 50 years have found
16、that theprevalence of AAA is 3.9% to 7.2% in men and 1.0% to1.3% in women (1, 2). It is important to consider poten-tial screening strategies for AAA because most AAAs areasymptomatic until they rupture. Although the risk forrupture varies greatly by aneurysm size, the associated riskfor death is as
17、 high as 75% to 90% (1, 2).DetectionEvidence is adequate that ultrasonography is a safe andaccurate screening test for AAA.Benefits of Detection and Early TreatmentMen Aged 65 to 75 Years Who Have Ever SmokedFour large, population-based, randomized, controlledtrials (RCTs) show that invitation to 1-
18、time screening forFigure.Screening for abdominal aortic aneurysm: clinical summary of U.S. Preventive Services Task Force recommendation.SCREENING FOR ABDOMINAL AORTIC ANEURYSM CLINICAL SUMMARY OF U.S. PREVENTIVE SERVICES TASK FORCE RECOMMENDATIONPopulationRecommendationRisk AssessmentBalance of Ben
19、efits and HarmsTreatmentScreening TestsRisk factors for AAA include older age; a positive smoking history; having a first-degree relative with an AAA; and having a history of other vascular aneurysms, coronary artery disease, cerebrovascular disease, atherosclerosis, hypercholesterolemia, obesity, o
20、r hypertension. Factors associated with a reduced risk for AAA include African American race, Hispanic ethnicity, and diabetes.Abdominal duplex ultrasonography is the standard approach for AAA screening. Screening with ultrasonography is noninvasive and easy to perform and has high sensitivity (94%
21、to 100%) and specificity (98% to 100%) for detection.Patients with large AAAs (5.5 cm) are referred for open surgical repair or endovascular aneurysm repair. Patients with smaller aneurysms (3.0 to 5.4 cm) are generally managed conservatively via surveillance (e.g., repeated ultrasonography every 3
22、to 12 mo).Early open surgery for the treatment of smaller AAAs does not reduce AAA-specific or all-cause mortality. Surgical referral of smaller AAAs is typically reserved for rapid growth (1.0 cm per year) or once the threshold of 5.5 cm on repeated ultrasonography is reached.Short-term treatment w
23、ith antibiotics or -blockers does not seem to reduce AAA growth.Men aged 65 to 75 y who have ever smoked*Screen once for abdominal aortic aneurysm (AAA) by ultrasonography.Grade: BWomen who have never smokedDo not screen for AAA.Grade: DWomen aged 65 to 75 y who have ever smoked*No recommendation.Gr
24、ade: I statementMen aged 65 to 75 y who have never smokedSelectively screen for AAA.Grade: CThere is a moderate net benefit of screening for AAA with ultrasonography in men aged 65 to 75 y who have ever smoked.The harms of screening for AAA in women who have never smoked outweigh any potential benef
25、its.The evidence of screening for AAA in women aged 65 to 75 y who have ever smoked is insufficient, and the balance of benefits and harms cannot be determined.There is a small net benefit of screening for AAA with ultrasonography in men aged 65 to 75 y who have never smoked.For a summary of the evi
26、dence systematically reviewed in making this recommendation, the full recommendation statement, and supporting documents, please go to www.uspreventiveservicestaskforce.org.* “Ever smoked” is defined as having smoked at least 100 cigarettes during a lifetime.Thisonline-firstversionwillbereplacedwith
27、afinalversionwhenitisincludedintheissue.Thefinalversionmaydifferinsmallways.Clinical GuidelineScreening for Abdominal Aortic Aneurysm2Annals of Internal Medicinewww.annals.orgDownloaded From: http:/annals.org/ on 06/24/AAA is associated with reduced AAA-specific mortality inmen. This benefit begins
28、3 years after testing and persistsup to 15 years (1, 2). In addition, risk reduction for AAArupture and emergency surgery persists up to 10 to 13years (1, 2).In the 2 highest-quality trials, the relative reduction inAAA-specific mortality after 13 years was 42% to 66% (3,4). In the largest trial, wh
29、ere prevalence of AAA was ap-proximately 5% in the screened group, screening was asso-ciated with an absolute risk reduction in AAA death of 1.4per 1000 men (3).Abdominal aortic aneurysms are most prevalent inmen who have ever smoked, occurring in approximately6% to 7% of this population (5, 6). Thi
30、s prevalence in-creases the importance of screening in these men because itmaximizes the absolute benefit that could be achieved (thatis, it improves the likelihood that men in this group willbenefit from screening). Convincing evidence shows that1-time screening for AAA with ultrasonography results
31、 in amoderate benefit in men aged 65 to 75 years who have eversmoked.Men Aged 65 to 75 Years Who Have Never SmokedScreening men overall reduces AAA-specific death,rupture, and emergency surgery. However, the lower prev-alence of AAA in men who have never smoked (approxi-mately 2%) (5) substantially
32、reduces the absolute benefit(that is, it greatly lowers the probability that men in thisgroup will benefit from screening). Adequate evidenceshows that 1-time screening for AAA with ultrasonographyresults in a small benefit in men aged 65 to 75 years whohave never smoked.Women Aged 65 to 75 Years Wh
33、o Have Ever SmokedOnly 1 RCT on screening for AAA included women(7). It detected no difference in the rate of AAA rupture,AAA-specific mortality, or all-cause mortality betweenwomen invited for screening and the control group (8).However, the trial was ultimately underpowered to detectdifferences in
34、 health outcomes by sex; as such, the resultsdo not rule out the possibility of a small benefit of screen-ing in this population.Women aged 70 years who have ever smoked have arelatively low prevalence of AAA (approximately 0.8%overall and approximately 2.0% for current smokers) (9).Evidence is inad
35、equate to conclude whether 1-time screen-ing for AAA with ultrasonography is beneficial in womenaged 65 to 75 years who have ever smoked.Women Who Have Never SmokedThe prevalence of AAA in women who have neversmoked is low (0.03% to 0.60% in women aged 50 to 79years) (5, 9). The evidence also shows
36、no apparent benefitof screening for AAA in women (8). The USPSTF there-fore concludes that adequate evidence shows that the ab-solute benefit of 1-time screening for AAA with ultra-sonography in women who have never smoked caneffectively be bounded at none or almost none.Harms of Detection and Early
37、 TreatmentIn the available trials, groups invited to screening wereapproximately twice as likely as control groups to have anyAAA surgery within 3 to 5 years, predominantly driven byan increase in elective surgeries. More than 90% of AAAsidentified by screening were below the 5.5-cm thresholdfor imm
38、ediate repair. Detecting smaller AAAs generallyleads to long-term (potentially lifelong) surveillance (1, 2).A persons risk for death related to elective surgery forAAA is lower than that for death related to emergencysurgery for AAA rupture. However, the increase in theoverall rates of detection an
39、d surgery in the screeninggroups still potentially represents a harm. A proportion ofAAAs will never rupture because they do not advance orbecause a person dies of a competing cause.The exact extent of overdiagnosis and overtreatment isdifficult to estimate. One study from Massachusetts Gen-eral Hos
40、pital reviewed 24 000 consecutive autopsies be-tween 1952 and 1975 and found that 75% of the 473patients who died with an undetected or unoperated AAAhad a cause of death not related to the AAA (41% of AAAswere ?5.1 cm in diameter) (10). Given that even electivetreatment of AAA is associated with so
41、me risk for periop-erative mortality, overtreatment is an important issueto consider when deciding whether to screen for thiscondition.One study reported that women had a higher risk fordeath related to AAA surgery than men; death rates ofwomen and men were approximately 7% versus 5% foropen repair
42、and 2% versus 1% for endovascular repair,respectively (11). Evidence is limited and conflicting aboutthe effect of screening for AAA on quality of life or psy-chological status (for example, anxiety) (1, 2). Convincingevidence shows that the harms associated with 1-timescreening for AAA with ultraso
43、nography are at least smallin all populations and potentially higher in women becauseof their higher risk for operative mortality.USPSTF AssessmentThe USPSTF concludes with high certainty thatscreening for AAA with ultrasonography in men aged 65 to75 years who have ever smoked has a moderate net ben
44、efit.The USPSTF concludes with moderate certainty thatscreening for AAA with ultrasonography in men aged 65 to75 years who have never smoked has a small net benefit.The USPSTF concludes that the evidence is insuffi-cient to determine the balance of benefits and harms ofscreening for AAA in women age
45、d 65 to 75 years who haveever smoked.The USPSTF concludes with moderate certainty thatthe harms of screening for AAA outweigh any potentialbenefits in women who have never smoked.Thisonline-firstversionwillbereplacedwithafinalversionwhenitisincludedintheissue.Thefinalversionmaydifferinsmallways.Clin
46、ical GuidelineScreening for Abdominal Aortic Aneurysmwww.annals.orgAnnals of Internal Medicine3Downloaded From: http:/annals.org/ on 06/24/CLINICALCONSIDERATIONSPatient Population Under ConsiderationThis recommendation applies to asymptomatic adultsaged 50 years or older.Assessment of RiskSmoking St
47、atusConsuming 100 or more cigarettes is commonly usedin epidemiologic literature to define an “ever-smoker.”However, the randomized trials of screening for AAA didnot gather specific data about participants smoking histo-ries. Occasional tobacco use for a short time in the past (forexample, occasion
48、al “social” smoking as an adolescent oryoung adult) is unlikely to have a pronounced biologicaleffect, and the odds ratio (OR) of developing a large (?5.0cm) AAA is actually less than 1.0 for prior smokers whohave quit for at least 10 years (12). However, observationalstudies have found that even a
49、relatively modest smokinghistory (for example, smoking a half-pack or less per dayfor fewer than 10 years) does increase the likelihood ofdeveloping a large AAA (12).Screening in Men Aged 65 to 75 Years Who HaveNever SmokedDespite the demonstrated benefits of screening forAAA in men overall, the low
50、er prevalence of AAA in malenever-smokers versus male ever-smokers suggests that cli-nicians should consider a patients risk factors and the po-tential for harm before screening for AAA rather thanroutinely offering screening to all male never-smokers. Im-portant risk factors for AAA include older a
