in the clinic abdominal aortic aneurysm · 2016. 7. 19. · aortic aneurysms. lancet....

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AbdominalAortic Aneurysm

Screening and Prevention page ITC5-2

Diagnosis page ITC5-4

Treatment page ITC5-9

Practice Improvement page ITC5-14

CME Questions page ITC5-16

Physician WriterFrank A. Lederle, MD

Section Co-EditorsChristine Laine, MD, MPHDavid R. Goldmann, MDHarold C. Sox, MD

The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP),including PIER (Physicians’ Information and Education Resource) andMKSAP (Medical Knowledge and Self-Assessment Program). Annals ofInternal Medicine editors develop In the Clinic from these primarysources in collaboration with the ACP’s Medical Education and Publish-ing Division and with the assistance of science writers and physicianwriters. Editorial consultants from PIER and MKSAP provide expertreview of the content. Readers who are interested in these primaryresources for more detail can consult http://pier.acponline.org and otherresources referenced in each issue of In the Clinic.

The information contained herein should never be used as a substitute forclinical judgment.

CME objective: To review the screening and prevention, diagnosis, treatment, and practice improvement for abdominal aortic aneurysm.

© 2009 American College of Physicians

®

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What factors increase the risk forAAA?Smoking is the most importantreversible risk factor for AAA. Inthe largest screening study (3), ahistory of cigarette smokingaccounted for 75% of all AAAs 4.0cm or greater in diameter. The asso-ciation with AAA is stronger forcurrent smokers than for formersmokers, increases with number ofyears smoked, and decreases withthe elapsed time after quitting.After adjustment for other risk fac-tors, AAA is several times morecommon in men than in women.Other factors associated with AAAinclude age, white race, and familyhistory of AAA (see Box).Abdominal aortic aneurysm is less common in patients with diabetes (3).

In a cross-sectional screening study, 126 196 veterans age 50 to 79 years under-went ultrasonography to detect AAA.Aneurysms 3.0 cm or greater in diameterwere present in 4.2% of participants. Theprincipal positive associations with AAAwere age, smoking, male sex, white race,family history of AAA, and atheroscleroticdiseases. This study first described the sur-prising and still unexplained inverse associ-ation of AAA with diabetes (3).

© 2009 American College of Physicians ITC5-2 In the Clinic Annals of Internal Medicine 5 May 2009

An aneurysm is a failure of the arterial wall that results in a balloon-like dilatation of a segment of the artery. Aortic aneurysms constitutethe 14th leading cause of death in the United States and the 10th

leading cause of death in older men, who are the principal victims (1). Diag-nosis of abdominal aortic aneurysm (AAA) is important because the naturalhistory is that of continued enlargement with potentially catastrophic conse-quences. Because the condition may be entirely asymptomatic, and when symp-toms are present, they may be nonspecific, the internist is often the first to evaluate the patient. Thus, understanding the disease, optimal diagnostic meth-ods, and management are crucial for primary care practitioners.

Approximately 80% of aortic aneurysms occur between the renal arteries andthe aortic bifurcation. Abdominal aortic aneurysm is present in more than5% of older men who have smoked. Each year in the United States, AAArupture causes 4500 deaths; another 1400 deaths result from the 45 000repair procedures done to prevent rupture (2).

Screening andPrevention

1. Silverberg E, BoringCC, Squires TS. Can-cer statistics, 1990.CA Cancer J Clin.1990;40:9-26.[PMID: 2104569]

2. McPhee JT, Hill JS,Eslami MH. Theimpact of gender onpresentation, therapy,and mortality ofabdominal aorticaneurysm in theUnited States, 2001-2004. J Vasc Surg.2007;45:891-9.[PMID: 17391899]

3. Lederle FA, JohnsonGR, Wilson SE, et al.The aneurysm detec-tion and manage-ment study screeningprogram: validationcohort and finalresults. AneurysmDetection and Man-agement VeteransAffairs CooperativeStudy Investigators.Arch Intern Med.2000;160:1425-30.[PMID: 10826454]

4. The UK SmallAneurysm Trial Partic-ipants. Mortalityresults for ran-domised controlledtrial of early electivesurgery or ultrasono-graphic surveillancefor small abdominalaortic aneurysms.Lancet.1998;352:1649-55.[PMID: 9853436]

What is the natural history ofAAA?The natural history of AAA is toenlarge slowly over a period of years.Abdominal aortic aneurysms of 4.0to 5.5 cm enlarge at a mean rate of0.3 cm per year, with less than 25%enlarging 0.5 cm or more per year(4, 5). Larger AAAs enlarge faster.The rate of enlargement for 3.0- to4.0-cm AAAs is one half that of4.0-to 5.5-cm AAAs (6), and onehalf again faster for AAAs greaterthan 5.5 cm (7). The enlargementrate differs among individuals andis faster with advancing age andcontinued smoking.

Most AAAs never rupture, butwhen rupture occurs, the mortal-ity rate is 80% (8). As a AAAenlarges, the risk for ruptureincreases. The rupture rate forAAAs of 4.0 to 5.5 cm in diame-ter is 0.7% to 1.0% per year (4, 5),higher than with AAAs less than4.0 cm. The rupture rate for smallAAA is higher in women than inmen (9). Men and women haveequivalent rupture rates for AAAsgreater than 5.5 cm (10). Rupturerates of AAAs greater than 5.5cm in otherwise healthy patientsare unknown and unlikely to beknown in the future because of


5. Aneurysm Detectionand ManagementVeterans AffairsCooperative StudyGroup. Immediaterepair compared withsurveillance of smallabdominal aorticaneurysms. N Engl JMed. 2002;346:1437-44. [PMID: 12000813]

6. Santilli SM, Littooy FN,Cambria RA, et al.Expansion rates andoutcomes for the 3.0-cm to the 3.9-cminfrarenal abdominalaortic aneurysm. JVasc Surg.2002;35:666-71.[PMID: 11932660]

7. Veterans Affairs Coop-erative Study #417Investigators. Rupturerate of large abdomi-nal aortic aneurysmsin patients refusingor unfit for electiverepair. JAMA.2002;287:2968-72.[PMID: 12052126]

8. Adam DJ, Mohan IV,Stuart WP, et al. Com-munity and hospitaloutcome from rup-tured abdominal aor-tic aneurysm withinthe catchment areaof a regional vascularsurgical service. JVasc Surg.1999;30:922-8.[PMID: 10550191]

© 2009 American College of PhysiciansITC5-3In the ClinicAnnals of Internal Medicine5 May 2009

general agreement that thesepatients need treatment. How-ever, in patients with AAAgreater than 5.5 cm who are unfitfor surgery, the rupture rate ishigh (7).

A 5-year prospective longitudinal studyfollowed 198 patients with AAA 5.5 cm orgreater who were not repaired electivelybecause of high operative risk or patientrefusal. More than one half of thepatients died during the study, 30%within 1 year of enrollment. The rate ofprobable AAA rupture was 10% per yearin the entire cohort, and more than 25%at 6 months for AAA 8.0 cm or greater.Whether these rates apply to healthierpatients is unknown, but they are usefulfor decision making in high operative riskpatients (7).

Who should clinicians screen forAAA and how should screening bedone?The U.S. Preventive Services TaskForce (USPSTF) now recommendsone-time screening with ultra-sonography to detect asympto-matic AAA in 65- to 75-year-oldmen who have ever smoked (11).The USPSTF does not make arecommendation for nonsmokingmen and recommends againstscreening women.

Medicare covers abdominal ultra-sonography to screen for AAA formen who have ever smoked andanyone with a family history ofAAA. Screening should take placeat the Welcome to Medicare visit,which must occur within 6months after beginning Medicareinsurance coverage.

The USPSTF based its recommen-dation to screen for AAA on asolid body of evidence. Four ran-domized trials of AAA screeninghave reported results. These trialsrandomly assigned one half ofpatients from a population list toreceive an invitation for ultrasono-graphy screening. Of these, 60% to80% attended the screening. Of themen who were screened, 4% to 8%

had AAAs 3.0 cm in diameter orlarger, and the frequency of electiveAAA repair was several-fold greaterin the invited groups than in theuninvited control groups. In ameta-analysis of these 4 trials per-formed for the USPSTF, meninvited to undergo screening had alower rate of AAA-related mortal-ity (odds ratio, 0.57 [95% CI, 0.45to 0.74]) (12).

In the Multicentre Aneurysm ScreeningStudy (MASS) conducted in the UnitedKingdom, 67 770 men age 65 to 74 yearswere randomly assigned to ultrasonogra-phy screening for AAA or usual care.Patients with AAA 5.5 cm or larger werereferred for elective repair. After a mean 7years of follow-up, deaths related to AAAwere significantly reduced from 196 in thecontrol group to 105 in the invited group.All-cause mortality was lower in thescreened group; the difference was of bor-derline statistical significance (13).

A recent meta-analysis of longer-term out-comes from the screening trials reported asmall but statistically significant reductionin all-cause mortality in the invitedpatients (odds ratio, 0.97 [95% CI, 0.94 to0.99]) (14).

These trials, added to those ofsmaller studies, form the basis ofthe USPSTF recommendation forAAA screening (11). They were notlimited to smokers and did notreport their results by such sub-groups as smoking status becausethe authors had little informationabout the control groups. The firsttrial included 9342 women, whodid not benefit from screening.However, the number of

Risk Factors for Abdominal AorticAneurysm• Older age• Smoking• Male sex• White race• Family history of abdominal aortic

aneurysm• Occlusive atherosclerotic disease


9. Brown LC, Powell JT.Risk factors foraneurysm rupture inpatients kept underultrasound surveil-lance. UK SmallAneurysm Trial Partic-ipants. Ann Surg.1999;230:289-96; dis-cussion 296-7.[PMID: 10493476]

10. Powell JT, Brown LC,Greenhalgh RM, et al.The rupture rate oflarge abdominal aor-tic aneurysms: is thismodified by anatom-ical suitability forendovascular repair?Ann Surg.2008;247:173-9.[PMID: 18156938]

11. U.S. Preventive Ser-vices Task Force.Screening forabdominal aorticaneurysm: recom-mendation state-ment. Ann InternMed. 2005;142:198-202.[PMID: 15684208]

12. Fleming C, WhitlockEP, Beil TL, et al.Screening forabdominal aorticaneurysm: a best-evidence systematicreview for the U.S.Preventive ServicesTask Force. AnnIntern Med.2005;142:203-11.[PMID: 15684209]

13. MulticentreAneurysm ScreeningStudy Group. A sus-tained mortality ben-efit from screeningfor abdominal aorticaneurysm. AnnIntern Med.2007;146:699-706.[PMID: 17502630]

14. Lindholt JS, NormanP. Screening forabdominal aorticaneurysm reducesoverall mortality inmen. A meta-analysisof the mid- andlong-term effects ofscreening forabdominal aorticaneurysms. Eur JVasc Endovasc Surg.2008;36:167-71,response to com-ment, 621-2.[PMID: 18485756]


AAA-related events in women wastoo small (10 ruptures in thescreened group vs. 9 in the controlgroup after 10 years of follow-up)to draw firm conclusions about theeffect of screening in women (15).

Several screening programs havereported the findings of repeatscreening (16, 17). Aneurysmswere less frequent and smallerthan on the initial screening,which is not surprising becausethe initial screening would havedetected the long-standing andtherefore larger AAAs that haddeveloped over the preceding

years. Consequently, most authorsand the USPSTF have concludedthat one-time screening after age65 is sufficient.

What should clinicians tellpatients to help them decreasetheir risk for AAA?Because the association with AAAis substantially stronger for cur-rent smokers than former smok-ers, it is reasonable to assume thatsmoking cessation will reduce therisk for AAA. Clinicians can citeincreased risk for AAA as anotherreason for patients to stop smoking.

Screening and Prevention... Abdominal aortic aneurysm is the 10th most commoncause of death in older men. Smoking is its most important modifiable risk factor,and former smokers have a progressively smaller risk for AAA than current smok-ers. Randomized trials show that screening substantially reduces the risk for AAA-related mortality. The USPSTF recommends one-time abdominal ultrasonographyscreening for male smokers age 65 to 75 years.

CLINICAL BOTTOM LINE

Diagnosisdespite descriptions of its variedpresentations dating back morethan a century. Although rupturedAAA usually presents with cata-strophic vascular collapse, it canpresent with normal blood pres-sure and hematocrit, althoughleukocytosis is usually present.Many physicians are unfamiliarwith the syndromes of sympto-matic unruptured AAA, in whichabdominal, flank, or back painprecedes rupture, and containedAAA rupture, in which thehematoma is sealed off in theretroperitoneum. Either of thesesyndromes can persist for days or,rarely, weeks before uncontainedrupture leads to death (19). Theclinician must be suspicious of thepossible presence of AAA whenencountering such symptoms inthe appropriate context. Interven-tion can be lifesaving.

How does AAA present?Before rupture, AAAs are nearlyalways asymptomatic. Detectionoccurs after abdominal palpation,radiologic imaging for other pur-poses, or imaging tests done toscreen for AAA. This sectionfocuses on diagnosing rupturedAAA, because it happens infre-quently in a physician’s career andis one of the true emergencies ofmedical practice.

Ruptured AAA is a leading causeof sudden death (18). Its most fre-quent findings are pain and tender-ness in the abdomen, flank, groin,or back. Other common symptomsinclude urinary retention, constipa-tion, urge to defecate, hypotension,transient syncope, sudden collapse,and shock.

Misdiagnosis of ruptured AAAremains disturbingly common,



15. Scott RA, Bridgewa-ter SG, Ashton HA.Randomized clinicaltrial of screening forabdominal aorticaneurysm inwomen. Br J Surg.2002;89:283-5.[PMID: 11872050]

16. Lederle FA, JohnsonGR, Wilson SE, et al.Yield of repeatedscreening forabdominal aorticaneurysm after a 4-year interval.Aneurysm Detectionand ManagementVeterans AffairsCooperative StudyInvestigators. ArchIntern Med.2000;160:1117-21.[PMID: 10789604]

17. Hafez H, Druce PS,Ashton HA. Abdomi-nal aortic aneurysmdevelopment inmen following a“normal” aortic ultra-sound scan. Eur JVasc Endovasc Surg.2008;36:553-8.[PMID: 18718773]

18. Thomas AC, Knap-man PA, Krikler DM,et al. Communitystudy of the causesof “natural” suddendeath. BMJ.1988;297:1453-6.[PMID: 3147014]

19. Lederle FA, ParentiCM, Chute EP. Rup-tured abdominalaortic aneurysm: theinternist as diagnos-tician. Am J Med.1994;96:163-7.[PMID: 8109601]

20. Lederle FA, Simel DL.The rational clinicalexamination. Doesthis patient haveabdominal aorticaneurysm? JAMA.1999;281:77-82.[PMID: 9892455]

How should clinicians use thehistory and physical examinationin diagnosing AAA?Unruptured AAAAlthough unruptured AAAs arealmost always asymptomatic, a his-tory of heavy tobacco use or a fam-ily history of AAA should heightenawareness in older persons, particu-larly men. The only physical exam-ination maneuver of demonstratedvalue is abdominal palpation todetect a widened aortic pulsation or“pulsatile mass”.

Physicians who care for olderpatients should become proficientat measuring the width of the aortabetween the 2 index fingers. Thewidth of the aortic pulsation pro-vides the key evidence of AAA, notits prominence or force, the pres-ence of bruits, or other findings.Palpating an AAA seems to besafe: No one has reported ruptureimmediately following palpation.However, abdominal palpationmisses many AAAs 5.0 cm orlarger in diameter and is even lesssensitive for smaller AAAs or inobese patients.

A systematic review pooled 15 studiesinvolving 2955 participants not previouslyknown to have AAA. Each was screenedwith both abdominal palpation and ultra-sonography, which served as the diagnos-tic reference standard. The sensitivity ofabdominal palpation ranged from 29% for AAA 3.0 to 3.9 cm, to 50% for AAA 4.0 to 4.9 cm, and 76% for AAA 5.0 cm orgreater. The positive predictive value ofpalpation for detecting AAA 3.0 cm orgreater was 43%. Abdominal obesityseemed to decrease the sensitivity of pal-pation. The authors concluded thatabdominal palpation had moderate sensi-tivity for detecting AAAs large enough tobe referred for surgery, but could not beused to exclude AAA (20).

On the basis of the estimates fromthis systematic review, a negativephysical examination reduces theodds that the patient has an AAA5.0 cm or larger by approximately25%. On the other hand, if the

examiner feels a pulsatile mass,imaging confirmation, usually ultra-sonography, is mandatory.

Ruptured AAAThe diagnosis of ruptured AAAcan be obvious or difficult. Themost important prerequisite is ahigh index of suspicion, especiallyin an older man who has smoked.Physicians must know the variouspresentations and be particularlysuspicious when the patient’s con-dition seems more serious thanwould be typical with an alternativeexplanation for flank or abdominalpain, such as pyelonephritis, diverti-culitis, or lumbar disk herniation.The Box lists signs and symptomsof ruptured AAA.

A pulsatile mass may be present butis often absent and should not berelied on to confirm rupture.Although ruptured AAAs tend tobe large, palpating one can be diffi-cult because of abdominal tender-ness, guarding, and intestinal dis-tention due to ileus. Studies ofruptured AAA that include post-mortem diagnoses of rupture havereported that a pulsatile mass ispalpable only about 50% of thetime (20), which means that anegative examination is very unre-liable. Table 1 describes the differ-ential diagnosis of pulsatile massand ruptured AAA, and Table 2lists the history and physicalexamination elements for rupturedand unruptured AAA.

Signs and Symptoms of RupturedAAA• Pain in the flank, abdomen, groin, or

back• Abdominal, flank, or back tenderness• Gastrointestinal dysfunction (constipa-

tion, distention, bleeding, urge todefecate)

• Urinary dysfunction (retention, difficulty voiding, renal colic)

• Syncope• Hypotension and shock


21. Lederle FA, WilsonSE, Johnson GR, et al.Variability in meas-urement of abdomi-nal aorticaneurysms. Abdomi-nal Aortic AneurysmDetection and Man-agement VeteransAdministrationCooperative StudyGroup. J Vasc Surg.1995;21:945-52.[PMID: 7776474]


Table 1. Differential Diagnosis of Pulsatile Mass and Ruptured Abdominal Aortic AneurysmDisease Characteristics Notes

Pulsatile massNormal aorta Examiner may be misled by prominent Clinical observation*

pulsation or subcutaneous fatPara-aortic nodes Mass adherent to normal aorta that can

transmit the aortic pulsationRuptured abdominal aortic aneurysm†

Gastrointestinal disease (such Abdominal pain, constipation, The expanding hematoma can as diverticulitis, bowel ischemia, leukocytosis cause gastrointestinal symptomspancreatitis, penetrating duodenal ulcer, by compressing the bowel.malignant conditions) Reduced blood pressure and

obstruction of aortic brancharteries can compromise bloodsupply to the gastrointestinal andurinary tracts.

Urinary tract disease (such as Flank pain, urinary retention, The expanding hematomastones, infection) leukocytosis can compress the ureters.

Reduced blood pressure andobstruction of aortic brancharteries can compromise bloodsupply to the urinary tract.

Spinal diseases (such as herniated disk, Severe back pain, nerve impingement bony metastases, lower extremity syndromesneuropathy)Incarcerated hernia Inguinal mass with pain and AAA often diagnosed at

tenderness surgery for incarcerated hernia‡

AAA = abdominal aortic aneurysm.* Nusbaum JW, Freimanis AK, Thomford NR. Echography in the diagnosis of abdominal aortic aneurysm. Arch Surg.1971;102:385-8. [PMID: 5553311]† Lederle FA, Parenti CM, Chute EP. Ruptured abdominal aortic aneurysm: the internist as diagnostician. Am J Med.1994;96:163-7. [PMID: 8109601]‡ Khaw H, Sottiurai VS, Craighead CC, Batson RC. Ruptured abdominal aortic aneurysm presenting as symptomatic inguinalmass: report of six cases. J Vasc Surg. 1986;4:384-9. [PMID: 3761483]

Table 2. History and Physical Examination Elements for Abdominal Aortic AneurysmCategory Element Sensitivity, % Specificity, % Likelihood Likelihood

Ratio Ratio Positive Negative

Unruptured abdominal aortic aneurysm

History Usually asymptomaticPhysical examination Abdominal palpation

AAA ≥3.0 cm 39 97 12.0 0.72AAA ≥4.0 cm 60 15.6 0.51AAA ≥5.0 cm 76All AAA ≤81 99.2

Ruptured abdominal aortic aneurysm

History Pain in abdomen, flank, 80–100or backConstipation 22Urinary retention 22Syncope 26

Physical examination Abdominal palpation for 40–60pulsatile abdominal massHypotension 50–70Abdominal tenderness 70–90Ecchymosis anywhere between diaphragm and knees

AAA = abdominal aortic aneurysm.


In an ultrasonography screening study(23), 4176 men age 65 to 73 years hadaortic diameter measurements by 2different examiners. The mean inter-observer difference was 0.1 mm, a highdegree of agreement.

Other tests have a very limitedrole. Plain abdominal radiographyoccasionally identifies AAA byshowing calcium deposits in theaneurysm wall, but has low sensi-tivity and does not provide anadequate measurement of AAAdiameter. Computed tomography(CT) may be useful when ultra-sonography fails to visualize theaorta clearly.

Ruptured AneurysmTable 3 lists laboratory and otherstudies for demonstration of AAA.Diagnosing a ruptured aneurysmmeans demonstrating extravascularblood in the retroperitoneum or

What imaging studies and otherlaboratory tests should cliniciansorder to evaluate patients withsuspected AAA?Unruptured AneurysmUltrasonography is the preferredtest for diagnosis and surveillanceof AAA in asymptomaticpatients. It is safe, accurate,and relatively inexpensive.When the examination is ade-quate, ultrasonography has a sen-sitivity and specificity of nearly100%. Bowel gas may cause aninadequate study, but a repeatedexamination after fasting is usu-ally successful. Lack of precision(usually <0.5 cm) may misclassifysome patients (21). Many inter-national organizations have concluded that diagnostic ultra-sonography has no verifiedadverse effects (22) and thereforeno contraindications.

22. Barnett SB, Ter HaarGR, Ziskin MC, et al.International recom-mendations andguidelines for thesafe use of diagnos-tic ultrasound inmedicine. Ultra-sound Med Biol.2000;26:355-66.[PMID: 10773365]


Table 3. Laboratory and Other Studies for Demonstration of Abdominal AorticAneurysm RuptureTest Sensitivity, % Specificity, % Notes

Abdominal 4 Using operative findings and clinical outcome ultrasonography as gold standard*.

Computed 79 77 Using operative findings as gold standard†.tomography 77 100 Differences between studies probably result

90 93 from the small number of patients.94 95

MR, MRA, Time is of the essence in the diagnosis of angiography rupture. MR, MRA, and angiography offer no

advantage over computed tomography andtake more time. Therefore, they are rarely ifever used for this purpose; therefore, operat-ing characteristics have not been reported.

Leukocyte count 70 Using operative findings, computed >11 x 109 cells/L tomography, or autopsy as gold standard‡.Hemoglobin <11 g/dL

MRA = magnetic resonance angiography.* Shuman WP, Hastrup W Jr, Kohler TR, et al. Suspected leaking abdominal aortic aneurysm: use ofsonography in the emergency room. Radiology. 1988;168:117-9. [PMID: 3289085]† Lederle FA, Wilson SE, Johnson GR, et al. Variability in measurement of abdominal aortic aneurysms.Abdominal Aortic Aneurysm Detection and Management Veterans Administration Cooperative StudyGroup. J Vasc Surg. 1995;21:945-52. [PMID: 7776474]Adam DJ, Bradbury AW, Stuart WP, et al. The value of computed tomography in the assessment of sus-pected ruptured abdominal aortic aneurysm. J Vasc Surg. 1998;27:431-7. [PMID: 9546228]Weinbaum FI, Dubner S, Turner JW, Pardes JG. The accuracy of computed tomography in the diagnosisof retroperitoneal blood in the presence of abdominal aortic aneurysm. J Vasc Surg. 1987;6:11-6.[PMID: 3599277]Zarnke MD, Gould HR, Goldman MH. Computed tomography in the evaluation of the patient withsymptomatic abdominal aortic aneurysm. Surgery. 1988;103:638-42. [PMID: 3375990]Kvilekval KH, Best IM, Mason RA, Newton GB, Giron F. The value of computed tomography in the man-agement of symptomatic abdominal aortic aneurysms. J Vasc Surg. 1990;12:28-33. [PMID: 2374251]‡ Lederle FA, Parenti CM, Chute EP. Ruptured abdominal aortic aneurysm: the internist as diagnosti-cian. Am J Med. 1994;96:163-7. [PMID: 8109601]



abdomen, which requires theresolving power of CT or magneticresonance imaging (MRI). If treat-ing the ruptured AAA is a realisticoption, obtain one of these testsimmediately when you suspect ruptured AAA and the patient ishemodynamically stable.

Computed tomography has 80%to 90% sensitivity for rupture(24). One study (25) demon-strated the difficulty of interpret-ing images in patients with sus-pected rupture. The authors foundthat multiple readings of CTagreed only moderately well aboutthe presence of rupture (K = 0.59interobserver, 0.69 intraobserver).Ultrasonography has low sensitiv-ity for rupture (26) but couldincrease the probability of thediagnosis by detecting a previ-ously undiagnosed AAA.

How do testing strategies differ depending on the initial presentation of AAA?Unruptured AneurysmWhen asymptomatic AAA is sus-pected (usually on the basis ofabdominal palpation or plain radio-graphy findings), abdominal imagingwith ultrasonography or CT willconfirm the diagnosis. Ultrasonogra-phy is preferred because it does notexpose the patient to radiation and isless expensive.

Suspected AAA RuptureWhen the presentation strongly sug-gests a ruptured AAA and thepatient is hemodynamically stable,obtain CT or MRI immediately,and be prepared for the occasional

ruptural AAA patient who hascardiovascular collapse in theradiology suite (19). For a patientwith abdominal pain and shock,obtain surgical consultationurgently to consider taking thepatient directly to the operatingroom. Abdominal ultrasonogra-phy can then be obtained whileresuscitation procedures areunderway.

When suspicion of AAA ruptureis lower, as in an elderly malesmoker with new onset of abdom-inal or back pain and clinical indicators of another diagnosis,physicians should still stronglyconsider obtaining abdominalultrasonography. Although ultra-sonography will not reliably diag-nose rupture, finding an AAA inthese patients will alert the phys-ician to pursue further evaluationwith CT or MRI.

What other disorders shouldclinicians consider in patientswith suspected AAA?Occasionally, para-aortic lymphnodes and lymphoma are largeenough to masquerade as AAA onabdominal palpation, ultrasono-graphy, and even CT (27, 28). Avariety of acute disorders of thegastrointestinal tract, urinary tract,and spine can produce symptomssimilar to ruptured AAA, but thefirst priority should be to excluderupture rather than pursue theseless serious conditions. Misdiag-noses resulting from similaritiesbetween ruptured AAA and otherconditions have been documented(19, 29).

23. Lindholt JS, VammenS, Juul S, et al. Thevalidity of ultrasono-graphic scanning asscreening method forabdominal aorticaneurysm. Eur J VascEndovasc Surg.1999;17:472-5.[PMID: 10375481]

24. Adam DJ, BradburyAW, Stuart WP, et al.The value of com-puted tomography inthe assessment of sus-pected rupturedabdominal aorticaneurysm. J Vasc Surg.1998;27:431-7.[PMID: 9546228]

25. Gloviczki P, PairoleroPC, Mucha P Jr, FarnellMB, Hallett JW Jr,Ilstrup DM, et al. Rup-tured abdominal aor-tic aneurysms: repairshould not be denied.J Vasc Surg.1992;15:851-7; discus-sion 857-9.[PMID: 1578541]

26. Shuman WP, HastrupW Jr, Kohler TR, et al.Suspected leakingabdominal aorticaneurysm: use ofsonography in theemergency room.Radiology.1988;168:117-9.[PMID: 3289085]

27. Nusbaum JW, Freima-nis AK, Thomford NR.Echography in thediagnosis of abdomi-nal aortic aneurysm.Arch Surg.1971;102:385-8.[PMID: 5553311]

28. Carro C, Camilleri L,Garcier JM, et al.Periaortic lymphomamimicking aorticaneurysm. Eur J Car-diothorac Surg.2004;25:1126.[PMID: 15145022]

29. Valentine RJ, Barth MJ,Myers SI, et al. Nonvas-cular emergenciespresenting as rup-tured abdominal aor-tic aneurysms.Surgery. 1993;113:286-9. [PMID: 8441963]

30. UK Small AneurysmTrial Participants.Abdominal aorticaneurysm expansion:risk factors and timeintervals for surveil-lance. Circulation.2004;110:16-21.[PMID: 15210603]

31. Smoking, lung func-tion and the progno-sis of abdominal aorticaneurysm. The UKSmall Aneurysm TrialParticipants. Eur J VascEndovasc Surg.2000;19:636-42.[PMID: 10873733]

Diagnosis... Most AAAs are diagnosed as an incidental finding during a physicalexamination. The most important factor in successfully diagnosing ruptured AAA isremembering to think of it in a person with new abdominal or flank pain.Although ultrasonography is an excellent test for unruptured AAA, making a defi-nite diagnosis of ruptured AAA requires showing blood in the retroperitoneum orabdomen, which requires CT or MRI.




32. PropanololAneurysm TrialInvestigators. Propra-nolol for smallabdominal aorticaneurysms: results ofa randomized trial. JVasc Surg.2002;35:72-9.[PMID: 11802135]

33. Wilmink ABM, Hub-bard CSFF, Day NE,et al. Effect of pro-pranolol on theexpansion ofabdominal aorticaneurysms: a ran-domized study[Abstract]. Br J Surg.2000;87:499.

34. Vammen S, LindholtJS, Ostergaard L, etal. Randomized dou-ble-blind controlledtrial of roxithromycinfor prevention ofabdominal aorticaneurysm expan-sion. Br J Surg.2001;88:1066-72.[PMID: 11488791]

35. Mosorin M, JuvonenJ, Biancari F, et al.Use of doxycyclineto decrease thegrowth rate ofabdominal aorticaneurysms: a ran-domized, double-blind, placebo-con-trolled pilot study. JVasc Surg.2001;34:606-10.[PMID: 11668312]

36. ACES Investigators.Azithromycin for thesecondary preven-tion of coronaryevents. N Engl JMed. 2005;352:1637-45. [PMID: 15843666]

37. Pravastatin or Ator-vastatin Evaluationand Infection Ther-apy Thrombolysis inMyocardial Infarc-tion 22 Investigators.Antiobiotic treat-ment of Chlamydiapneumoniae afteracute coronary syn-drome. N Engl JMed. 2005;352:1646-54. [PMID: 15843667]

38. Velicer CM, HeckbertSR, Lampe JW, et al.Antibiotic use inrelation to the risk ofbreast cancer. JAMA.2004;291:827-35.[PMID: 14970061]

39. Powell JT, Brown LC,Forbes JF, et al. Final12-year follow-up ofsurgery versus sur-veillance in the UKSmall AneurysmTrial. Br J Surg.2007;94:702-8.[PMID: 17514693]

TreatmentWhat lifestyle modificationsshould clinicians recommend topatients with AAA?Smokers with AAA should receiveassistance with smoking cessation,which could help prevent diseaseprogression. Data from the UKSmall Aneurysm Trial groupdemonstrate that, compared withformer smokers, AAA enlargedmore rapidly in current smokers(30) and was more likely to rupture(9, 31).

What is the role of drug therapyin the management of patientswith asymptomatic AAA?Medical treatment to reduce the rate of enlargement of small AAAsis an area of active research, but notreatments have been proven effec-tive. Targets of therapy include sev-eral purported pathophysiologicmechanisms, including hemodynam-ics, inflammation, and proteaseactivity. Doxycycline, statins, andangiotensin-converting enzymeinhibitors have shown promisingresults, but all remain unproven andare not recommended outside ofrandomized trials.

Antihypertensive AgentsIn the only large trials (32, 33), theβ-blocker propranolol did not slowthe rate of AAA enlargement. How-ever, increased mean blood pressureis associated with increased risk forAAA rupture (9), so AAA is yetanother reason to treat hypertension,which should be managed with theusual therapy.

AntibioticsInterest in antibiotic therapy isbased on evidence of chronicinflammation in AAA, inhibitionof proteases and of inflammationby some antibiotics, and possibleinvolvement of Chlamydia pneumo-niae in the pathogenesis of AAA.Two small randomized trials havereported reduced rates of AAAenlargement in the months

following a course of antibiotics,but substantial losses to follow-upin one (34) and baseline differ-ences in the other (35) render thefindings inconclusive and prelimi-nary. Antibiotics have manyadverse effects, and the benefits inpatients with AAA remain uncer-tain. In large trials, antibioticsintended to prevent hypothesizedeffects of chlamydia infection onprogression of atherosclerosis didnot reduce cardiovascular events(36, 37). In addition, long-termuse of antibiotics has been associ-ated with an increased risk forbreast cancer (38). With uncertainbenefits and some known harms,the role of antibiotics in the long-term management of AAA is asyet undetermined.

When should clinicians recommendsurgery in patients withasymptomatic AAA?Elective AAA repair is indicatedwhen the risk for rupture is highenough to balance the risks of sur-gery. The strongest known predic-tor of AAA rupture is its maximalexternal diameter, which is theprincipal objective criterion foroffering elective repair. The rate ofenlargement seems as if it shouldpredict rupture, but current evi-dence provides no support forusing this measure. Therefore,the widely used rule is to considerAAA patients for repair only when the AAA exceeds 5.5 cm in diameter.

The United Kingdom Small Aneurysm Trial(UKSAT) (4, 39) and the Aneurysm Detec-tion and Management (ADAM) trial (5)randomly assigned 1090 and 1136 pati-ents, respectively, with AAA 4.0 to 5.4 cm in diameter to immediate elective open repairor periodic imaging surveillance leading torepair when an AAA enlarged beyond 5.5 cm or became symptomatic. The pri-mary outcome, all-cause mortality, wasthe same in the 2 intervention groups inboth trials, as was quality of life, suggesting


that elective repair of AAA smaller than5.5 cm did not change health outcomes.Because of these influential trials, electiverepair is usually reserved for AAA largerthan 5.5 cm.

Do the outcomes of endovascularand open AAA repair differ?Open surgery is the traditionalmethod of AAA repair. The aortais exposed and cross-clamped, theaneurysm is opened, lumbar andother tributary arteries are tied off to control back bleeding, asynthetic graft is sewn into placeunder direct vision, and the aorta is then closed around thegraft. Elective open repair is asso-ciated with an operative mortalityrate of 2% to 5%, considerablemorbidity, and a long conva-lescence (Table 4).

In the National Inpatient Sample, 220 403hospital discharges in the United Statesfrom 2001 to 2004 were for AAA. A total of45 000 repairs of intact AAA were per-formed per year, with an in-hospital mor-tality rate of 4.5% for open repair and1.0% for endovascular repair. Of the 10000 patients hospitalized for rupturedAAA each year, 68% had surgery, with amortality rate of 37.3%. Women had asubstantially higher mortality rate thanmen (2).

Endovascular repair involves intro-ducing an expandable graft systemthrough the femoral or iliac arteriesinto the aneurysmal region of theaorta and iliac arteries. When the

graft is in place, the AAA, whichremains intact, is not exposed toarterial pressure, which should pre-vent it from growing and rupturing.Endovascular repair requires a seg-ment of normal aorta below therenal arteries and also requires iliacarteries that are free of excessiveplaque or tortuosity. These require-ments exclude about one third ofpatients.

The advantages of endovascularrepair compared with open repairare reduced operative morbidity andshorter initial hospital stay andoverall recovery time. However,many studies have found thatendovascular repair is more expen-sive than open repair, due primarilyto the high price of the grafts. Inrandomized trials, endovascularrepair of AAA has lower periopera-tive mortality than open repair, butmortality rates after 2 years aresimilar (40, 41).

What criteria identify patientswho are candidates forendovascular versus openaneurysm repair?The long-term results of endovas-cular repair are unknown, althoughthe randomized trials are continu-ing to monitor outcomes. Becauseof the uncertainty about long-termresults, many physicians recom-mend open repair in youngerpatients.


40. EVAR trial partici-pants. Endovascularaneurysm repair ver-sus open repair inpatients withabdominal aorticaneurysm (EVAR trial1): randomised con-trolled trial. Lancet.2005;365:2179-86.[PMID: 15978925]

41. Dutch RandomizedEndovascularAneurysm Manage-ment (DREAM) TrialGroup. Two-yearoutcomes after con-ventional orendovascular repairof abdominal aorticaneurysms. N Engl JMed. 2005;352:2398-405.[PMID: 15944424]

42. EVAR trial partici-pants. Endovascularaneurysm repair andoutcome in patientsunfit for open repairof abdominal aorticaneurysm (EVAR trial2): randomised con-trolled trial. Lancet.2005;365:2187-92.[PMID: 15978926]

Table 4. Elective Endovascular Versus Open AAA RepairVariable Open Repair Endovascular Repair

Cost High HigherProportion of patients that 10%–20% 33%

can’t undergo procedurePerioperative mortality rate 2%–5% 0%–2%Postoperative complications Relatively low (8%) High (35%)Perioperative morbidity High LowOutcomes Initially worse but equivalent Initially better but equivalent

after 2 years after 2 yearsCertainty of very long-term Well documented Not known

outcomes4-year reintervention rates* 6% 20%

AAA = abdominal aortic aneurysm.* Ratzan RM, Donaldson MC, Foster JH, Walzak MP. The blue scrotum sign of Bryant: a diagnostic clueto ruptured abdominal aortic aneurysm. J Emerg Med. 1987;5:323-9. [PMID: 3624839]


The United Kingdom EndovascularAneurysm Repair trial 1 (EVAR-1) ran-domly assigned 1082 patients with AAA5.5 cm or greater to either open or endo-vascular repair. Postoperative mortalityrate (30-day or inpatient) was signifi-cantly lower in the endovascular group,but after a median 2.9 years follow-up,all-cause mortality was the same. Post-operative complications occurred 4times more frequently after endovascu-lar repair (40).

Because endovascular repair is lessinvasive, vascular disease special-ists thought that high-riskpatients would have better out-comes with it. However, 2 ran-domized trials from the UnitedKingdom suggest otherwise. Inone study (42), endovascularrepair conferred no all-cause mor-tality advantage over open repairin the least fit randomized sub-group at 4 years. In the other(43), endovascular repair was notbeneficial in patients consideredunfit for open repair.

The United Kingdom EndovascularAneurysm Repair trial 2 (EVAR-2) ran-domly assigned 338 patients unfit foropen repair with AAA 5.5 cm or greater tohave endovascular repair or observation.All-cause mortality (the primary out-come) and AAA-related mortality werethe same in the 2 groups. Ruptures beforedelayed repair, high operative mortality,and high cross-over rates led to questionsabout the validity of the findings, but it isthe only randomized trial in this patientpopulation (42).

When should clinicians hospitalizepatients with AAA?Clinicians should hospitalizepatients for elective aneurysmrepair when the diameter of theAAA reaches 5.5 cm. Electiveopen or endovascular AAA surgery at a high-volume hospital(at least 30 cases per year) is asso-ciated with lower operative mortality (44, 45).

Hospitalize patients with sus-pected AAA rupture immediately

for emergency diagnostic testingand possible AAA repair, alsopreferably in a high-volume hospital (44).

How should clinicians managepatients with suspected rupturedAAA?If the patient has abdominal painand shock, surgical consultationshould be obtained urgently todecide whether to take the patientdirectly to the operating room and perform ultrasonographywhile resuscitation procedures are underway. If an imaging testshows AAA rupture, surgical consultation should be obtainedimmediately to decide whether to take the patient directly to theoperating room. Emergency repair is the patient’s only chancefor survival, according to caseseries that show that unrepairedAAA rupture is almost alwaysfatal. Case series have shown apossible survival advantage forendovascular compared with open repair for ruptured AAA,but observational studies of treatments are often unreliablebecause of confounding by indication and other selectionbiases. Researchers in the UnitedKingdom are beginning a ran-domized trial comparing openwith endovascular repair for ruptured AAA.

The syndrome of symptomaticunruptured AAA requires physicians to make a very diffi-cult decision. They should consider this syndrome when the patient has an AAA andabdominal, flank, or back pain but imaging does notdemonstrate rupture. The problem is whether to proceedwith immediate surgery. Symp-toms, the diameter of the AAA,other imaging findings, and thegeneral health of the patient arethe main factors to take intoaccount.


43. Brown LC, Green-halgh RM, Howell S,et al. Patient fitnessand survival afterabdominal aorticaneurysm repair inpatients from the UKEVAR trials. Br J Surg.2007;94:709-16.[PMID: 17514695]

44. Killeen SD, AndrewsEJ, Redmond HP, etal. Provider volumeand outcomes forabdominal aorticaneurysm repair,carotid endarterec-tomy, and lowerextremity revascular-ization procedures. JVasc Surg.2007;45:615-26.[PMID: 17321352]

45. Dimick JB, UpchurchGR Jr. Endovasculartechnology, hospitalvolume, and mortal-ity with abdominalaortic aneurysm sur-gery. J Vasc Surg.2008;47:1150-4.[PMID: 18440178]


When should clinicians consultspecialists in managing patientswith AAA?Obtain vascular surgery consulta-tion for asymptomatic AAA 5.5 cmor greater in outside diameter forpatients who are possible candi-dates for repair and for patientswith AAA who develop symptomsconsistent with rupture.

Cardiology consultation may behelpful before elective AAA repairfor advice on whether to do noninvasive testing or coronaryangiography in patients with coronary artery disease, diabetes,renal insufficiency, or poor func-tional status. Algorithms estab-lished by the American College of Cardiology/American HeartAssociation for evaluation before AAA repair identifypatients at increased risk for cardiac death following aortic surgery (46, 47). However, in arandomized trial, coronary revascularization before surgerydid not improve the perioperative

46. American College ofCardiology.ACC/AHA guidelineupdate for perioper-ative cardiovascularevaluation for non-cardiac surgery—-executive summary:a report of theAmerican College ofCardiology/Ameri-can Heart Associa-tion Task Force onPractice Guidelines(Committee toUpdate the 1996Guidelines on Peri-operative Cardiovas-cular Evaluation forNoncardiac Surgery).J Am Coll Cardiol.2002;39:542-53.[PMID: 11823097]

47. Samain E, Farah E,Lesèche G, et al.Guidelines for peri-operative cardiacevaluation from theAmerican College ofCardiology/Ameri-can Heart Associa-tion task force areeffective for stratify-ing cardiac riskbefore aortic sur-gery. J Vasc Surg.2000;31:971-9.[PMID: 10805888]

48. McFalls EO, Ward HB,Moritz TE, et al. Coro-nary-artery revascu-larization beforeelective major vas-cular surgery. N EnglJ Med.2004;351:2795-804.[PMID: 15625331]


myocardial infarction rate or long-term mortality (48).

The Coronary Artery RevascularizationProphylaxis (CARP) trial randomized 510patients who were having elective openabdominal surgery for AAA or arterialocclusive disease and who had a coro-nary stenosis of at least 70% to preoper-ative coronary revascularization or norevascularization (48). Patients wereexcluded if they had unstable angina,more than 50% left main disease, ejec-tion fraction less than 20%, or severeaortic stenosis. Revascularization didnot improve 30-day operative mortality,myocardial infarction, or long-termmortality rates (mean follow-up, 2.7years). The findings suggest that cardiacintervention is unnecessary for mostpatients having elective AAA repair.

How should clinicians monitor patients with anasymptomatic AAA that does not meet the criteria for intervention?Table 5 lists elements of follow-up for AAA. In patients whoseAAA is below the threshold forelective repair, ultrasonography

Table 5. Elements of Follow-up for Abdominal Aortic AneurysmCategory Issue Method of Follow-up Frequency Notes

History Development of Ask about As soon symptoms abdominal, flank, as they occur

or back pain and at each visitPhysical Enlargement of Abdominal Each visit Optional, does

examination AAA examination not replaceultrasonography

Laboratory testing Enlargement of AAA diameter by Every 6 to 12 unrepaired AAA ultrasonography months, depending

on AAA diameterLaboratory testing Status of Computed Annually after first

endovascular graft tomography yearNondrug therapy Need for surgery Determine if size Each visit

of AAA is >5.5 cm; ask about symptoms

Drug therapy Treatment of Antihypertensives Ongoing Treatment of concurrent medical hypertension of problems, such as undetermined hypertension value for pre-

venting rupturePatient education Symptom Ask patients to Each visit

recognition in report abdominal, patients with flank, or AAA under back painobservation

AAA = abdominal aortic aneurysm.


49. American Associa-tion for VascularSurgery. ACC/AHA2005 guidelines forthe management ofpatients withperipheral arterialdisease (lowerextremity, renal,mesenteric, andabdominal aortic):executive summarya collaborativereport from theAmerican Associa-tion for VascularSurgery/Society forVascular Surgery,Society for Cardio-vascular Angiogra-phy and Interven-tions, Society forVascular Medicineand Biology, Societyof InterventionalRadiology, and theACC/AHA Task Forceon Practice Guide-lines (Writing Com-mittee to DevelopGuidelines for theManagement ofPatients With Periph-eral Arterial Disease)endorsed by theAmerican Associa-tion of Cardiovascu-lar and PulmonaryRehabilitation;National Heart, Lung,and Blood Institute;Society for VascularNursing; TransAt-lantic Inter-SocietyConsensus; and Vas-cular Disease Foun-dation. J Am CollCardiol.2006;47:1239-312.[PMID: 16545667]

50. Grimshaw GM,Thompson JM,Hamer JD. A statisti-cal analysis of thegrowth of smallabdominal aorticaneurysms. Eur JVasc Surg.1994;8:741-6.[PMID: 7828753]

51. McCarthy RJ, ShawE, Whyman MR, et al.Recommendationsfor screening inter-vals for small aorticaneurysms. Br J Surg.2003;90:821-6.[PMID: 12854107]

52. Hallett JW Jr, Mar-shall DM, PettersonTM, et al. Graft-related complica-tions after abdomi-nal aortic aneurysmrepair: reassurancefrom a 36-year pop-ulation-based expe-rience. J Vasc Surg.1997;25:277-84; dis-cussion 285-6.[PMID: 9052562]


imaging surveillance to assessaneurysm diameter is recom-mended every 6 to 12 months if the AAA diameter is 4.0 to 5.4 cm and every 2 to 3 years if it is less than 4.0 cm (49).

As noted previously, a large ran-domized trial (5) showed thatimaging at intervals of 6 monthswas equivalent to a strategy ofimmediate repair of AAAs meas-uring 4.0 to 5.4 cm. Observa-tional studies that monitoredenlargement rates suggest thatsurveillance intervals of up to 3years are safe for smaller AAAs(6, 50, 51). In deciding when torecommend repair, physiciansshould remember that errors ofup to 0.5 cm in measuring thediameter of an AAA are commonwith abdominal ultrasonographyor CT (21).

How should clinicians monitorpatients after aortic aneurysmrepair?The monitoring strategy dependson the method of AAA repair.After open repair, the graft failure

rate is very low (about 0.3% peryear), and no specific follow-up is recommended (5, 52, 53).Endovascular repair is associatedwith more late graft problems (for example, endoleaks, graftmigration or kinking, continuedAAA enlargement) and resultingreinterventions. In the EVAR-1trial (40), 20% of patients ran-domly assigned to endovascularrepair required reinterventionwithin 4 years compared with 6%of those randomly assigned toopen repair. Current practice,which is derived from the deviceapproval trials but not based oncomparative trials, is to performCT at 1, 6, and 12 months afterendovascular repair and thenannually for the rest of thepatient’s life. This strategy is aconsiderable burden for bothpatients and vascular surgeons; isexpensive; and results in substan-tial radiation exposure, especiallywith the commonly used triphasicCT protocol. Alternative follow-up methods are under activeinvestigation.

Treatment... Elective repair of AAA is indicated when the external diameterreaches 5.5 cm. Below that size, randomized trials show that repair does notimprove outcomes. Smoking cessation treatment and control of high bloodpressure are indicated. Surveillance abdominal ultrasonography is indicated foraneurysms smaller than 5.5 cm, with more frequent surveillance as the diame-ter approaches 5.5 cm. The choice between open elective repair and endovascu-lar repair is difficult. Endovascular repair has less mortality and morbidity inthe perioperative period but all-cause mortality and other outcomes are equiv-alent by 2 years, and the very long-term outcomes of endovascular repair areunknown. The treatment for ruptured AAA is immediate repair, either open orendovascular.




inthe

clinicTool Kit

in the clinic

Abdominal Aortic Aneurysm

PIER Moduleswww.pier.acponline.orgAccess the following PIER module: Abdominal aortic aneurysm. PIER modules provide evidence-based, updated information on current diagnosis, treatment, and management, in anelectronic format designed for rapid access at the point of care.Patient Education Resourceswww.annals.org/intheclinic/AAA.htmlAccess the Patient Information material on the following page for duplication and distributionto patients.www.medicinenet.com/abdominal_aortic_aneurysmAbdominal Aortic Aneurysm index from Medicinenet.comClinical Guidelineswww.annals.org/cgi/reprint/142/3/198.pdfU.S. Preventive Services Task Force on screening for AAAQuality Measures for AAAqualityindicators.ahrq.gov/downloads/iqi/iqi_guide_v31.pdfGuide to Inpatient Quality Indicators, from the Agency for Healthcare Research and Quality(AAA is discussed on pp. 25, 26, 39, and 40)www.qualitymeasures.ahrq.gov/summary/summary.aspx?doc_id=12739Abdominal aortic aneurysm repair, from the National Quality Measures Clearinghouse

ultrasonography screening in menage 65 to 75 years old who have eversmoked or have a first-degree rela-tive with AAA; advice to stop smok-ing; open or endovascular repair ofAAA 5.5 cm or larger in diameter;imaging surveillance of AAA 4.0 to5.4 cm at 6- to 12-month intervalsand 2- to 3-year intervals for AAAless than 4.0 cm; and immediateevaluation and repair of rupturedAAA. However, the guideline con-tains several recommendations thatconflict with randomized trial find-ings, including long-term b-blockade to slow the rate of AAAenlargement. The guideline alsostates that “Repair can be beneficialin patients with infrarenal or juxta-renal AAAs 5.0 to 5.4 cm in diame-ter,” an opinion that prompted a let-ter of dissent from the directors ofthe 2 randomized trials (55).

How should clinicians educatepatients with AAA?Patients with AAA should knowabout the course, management, andprognosis of AAA and importantself-management issues, includingthe importance of smoking cessa-tion, the need to report symptomsimmediately, the scheduling of regu-lar follow-up visits for surveillancebefore repair and after endovascularrepair, and the available surgicaloptions. Physicians have a responsi-bility to provide them with thisinformation.

What do professionalorganizations recommend aboutthe care of patients with AAA?The U.S. Preventive Services TaskForce (USPSTF) recommends one-time screening for AAA with ultra-sonography in men age 65 to 75years who have ever smoked (11). Itdoes not recommend for or againstscreening in 65- to 75-year-old menwho have never smoked. The USPSTF recommends against rou-tine screening in women.

The Joint Council (54) recom-mended 5.5-cm diameter as theappropriate threshold for electiverepair in most patients, on the basisof the finding of 2 randomized trials(4, 5, 39) that patients did not bene-fit from repairing AAA less than 5.5cm in diameter. However, the Coun-cil also recommended repair ofsmaller AAA in various patientgroups, including women, youngerpatients, and patients of surgeonswhose operative mortality rate is low.The last recommendation is basedon weak evidence (observationalstudies) and personal opinion andconflicts with randomized trial evi-dence that repair of small aneurysmsconfers no benefit.

The American College of Cardiol-ogy and the American Heart Asso-ciation’s peripheral arterial diseaseguideline (49) contains a number ofwell-supported recommendationsabout AAA, including one-time

PracticeImprovement

53. Johnston KW. Non-ruptured abdominalaortic aneurysm: six-year follow-upresults from the mul-ticenter prospectiveCanadian aneurysmstudy. CanadianSociety for VascularSurgery AneurysmStudy Group. J VascSurg. 1994;20:163-70. [PMID: 8040938]

54. Joint Council of theAmerican Associa-tion for VascularSurgery and Societyfor Vascular Surgery.Guidelines for thetreatment ofabdominal aorticaneurysms. Reportof a subcommitteeof the Joint Councilof the AmericanAssociation for Vas-cular Surgery andSociety for VascularSurgery. J Vasc Surg.2003;37:1106-17.[PMID: 12756363]

55. Lederle FA, PowellJT, Greenhalgh RM.Repair of smallabdominal aorticaneurysms [Letter].N Engl J Med.2006;354:1537-8.[PMID: 16598058]


WHAT YOU SHOULD KNOWABOUT ABDOMINAL AORTICANEURYSM

In the ClinicAnnals of Internal Medicine

annals.org

What is an abdominal aortic aneurysm?Blood moves from the heart to other

parts of the body through arteries.The abdominal aorta is the mainartery in the belly, which is alsocalled the abdomen. An abdominalaortic aneurysm (AAA) occurs whenthe wall of the aorta gets too big.This is caused by a weakening of thewall of the aorta. If the enlargedaorta breaks, blood can then leakinto the body.

Is AAA a big problem?Yes. It is the 14th most common cause of death in the

United States. In older men, it is the 10th mostcommon cause of death.

What are the symptoms of AAA?There are no symptoms of AAA until it breaks. If blood

does leak out, there may be pain in the back orbelly, weakness, or fainting.

How is AAA found?The doctor may feel the AAA when pressing on the

belly. The best way to find AAA is by doing a testcalled an ultrasonography of the abdomen.

Who should have a screening test forAAA?A screening test is done to look for a disease when

there are no symptoms. Experts recommend thatolder men who smoke should have a screening testfor AAA. Experts do not recommend a screeningtest for other people.

Who is most likely to have an AAA?Cigarette smoking makes the chances of having an

AAA greater than anything else. Being older, ofwhite race, male, and a smoker all add to the riskfor having an AAA.

If screening finds AAA, what shouldbe done?The greatest chance that the AAA could break is if it is

larger than 2 in (5.5 cm). If it is smaller than 2 in,the doctor will do an ultrasonography test, tell thepatient to stop smoking, and treat the patient’shigh blood pressure. If the AAA is 2 in or more, doc-tors usually do surgery to fix it.

Patie

nt In

form

atio

nFor More Information

Web Sites With Information onAbdominal Aortic Aneurysm:

www.medem.com/medlib/article/ZZZVTBUUBZEJAMA Patient Page: Aortic Aneurysms

www.medicinenet.com/abdominal_aortic_aneurysmAbdominal Aortic Aneurysm index from

Medicinenet.com


© 2009 American College of Physicians In the Clinic Annals of Internal Medicine

CME Questions

A 75-year-old asymptomatic man under-goes his annual examination. He is obeseand has a long history of smoking, hyper-tension, and chronic kidney disease (crea-tinine level, 2.7 mg/dL [238.73 µmol/L]).His medications are furosemide, ramipril,atorvastatin, and aspirin.

On physical examination, the bloodpressure is 170/78 mm Hg bilaterally,and pulse rate is 70/min and regular.There is a 2/6 holosystolic murmur heardat the apex with radiation to the axilla.There is a soft systolic abdominal bruitand a mildly tender midline pulsatilemass. There are bilateral femoral bruitswith absent distal pulses. Laboratorystudies show a total cholesterol level of200 mg/dL (5.17 mmol/L), HDL choles-terol level of 32 mg/dL (0.83 mmol/L),and LDL cholesterol level of 132 mg/dL(3.41 mmol/L). The patient is encouragedto stop smoking.

In addition to increasing the antihyper-tensive medications, what is the mostappropriate next step in this patient’smanagement?

A. Abdominal radiographB. Abdominal computed tomography

scan with contrastC. Abdominal ultrasoundD. Contrast aortography

A 74-year-old woman undergoes a rou-tine evaluation. She is a smoker and hashypertension, hypercholesterolemia, andtype 2 diabetes mellitus. Last year, shehad an asymptomatic 4.4-cm infrarenalabdominal aortic aneurysm diagnosedduring an ultrasonography for suspectedgallstones, at which time she wasencouraged to stop smoking. She ispetite, active, asymptomatic, and com-pliant with her medications, whichinclude atenolol, glyburide, metformin,lisinopril, and aspirin.

On physical examination, the bloodpressure is 125/78 mm Hg, and thepulse rate is 70/min and regular. Thelungs are clear; cardiac examinationshows an S4, and abdominal examina-tion shows a nontender abdomen with a

pulsatile mass. A follow-up ultrasonog-raphy shows a 5.1-cm aneurysm withthrombus. The patient is again encour-aged to stop smoking.

What is the most appropriate next stepin this patient’s management?

A. Repeat ultrasonography in 6months

B. Increase atenolol, repeatultrasonography in 6 months

C. Elective aneurysm repairD. Start warfarin (international

normalized ration, 2–3), repeatultrasonography in 6 months

A 67-year-old woman comes to youroffice because of intermittent lower backpain of 4 days’ duration. The pain is dull,nonradiating, and nonpositional, and isunrelated to meals or exertion. She hasno dyspnea, chest pain, or dysuria, and nohistory of trauma. She has a history ofhypercholesterolemia and underwent acholecystectomy at age 45 years. She alsohas a history of recurrent urinary tractinfections. She stopped smoking 10 yearsago. Her only medication is simvastatin,20 mg every night orally.

On physical examination, blood pressureis 145/85 mm Hg and heart rate is 86beats/min and regular. The patient isafebrile. Jugular venous pressure is nor-mal. Carotid pulses are 2+ bilaterally,without bruits. Cardiac examinationshows S4; the findings are otherwisenormal. The lungs are clear to ausculta-tion. Abdominal examination shows amidline pulsatile mass. No spinal or cos-tovertebral angle tenderness is noted.Distal pulses are normal.

Laboratory findings include hematocritof 36%, leukocyte count of 9.5 × 109

cells/L, platelet count of 290 × 109

cells/L, and serum creatinine level of 1.5mg/dL (114.38 µmol/L). Results of uri-nalysis are normal. The LDL cholesterollevel is 115 mg/dL (2.98 mmol/L).Abdominal ultrasound shows a 4.8-cmabdominal aortic aneurysm that origi-nates from the celiac trunk and extendsbelow the renal arteries.

Which of the following is the mostappropriate next step?

A. Initiate treatment withmetoprolol, 25 mg twice a dayorally, and schedule a follow-upvisit with ultrasonography in 6months.

B. Increase the dose of simvastatinto 40 mg/d and schedule afollow-up visit withultrasonography in 3 months.

C. Hospitalize the patient, order ahigh-resolution computedtomography scan, and obtain avascular surgery consultation.

D. Hospitalize the patient; initiatetreatment with metoprolol, 25 mgtwice a day; and refer the patientto a vascular surgeon.

E. Initiate treatment withmetoprolol, 25 mg twice a dayorally, and order magneticresonance imaging of the spine.

A 72-year-old man is evaluated duringa routine examination. He has a 45-pack-year history of smoking but quitsmoking 10 years ago. He is fit andexercises aggressively. He has noknown coronary artery disease and nomedical problems.

On physical examination, BMI is 26.4kg/m2. Pulse rate is 62/min, and bloodpressure is 118/64 mm Hg. Serum totalcholesterol level is 175 mg/dL (4.53mmol/L), serum high-density lipoproteincholesterol level is 52 mg/dL (1.34mmol/L), serum low-density lipoproteincholesterol level is 102 mg/dL (2.64mmol/L), serum triglyceride level is 105mg/dL (1.19 mmol/L).

Which of the following is most appro-priate next step in the management ofthis patient?

A. Electron-beam computedtomography for calcium score

B. Carotid artery ultrasonographyC. Ultrasound to evaluate for

abdominal aortic aneurysmD. Statin therapy

Questions are largely from the ACP’s Medical Knowledge Self-Assessment Program (MKSAP). Go to www.annals.org/intheclinic/ to obtain up to 1.5 CME credits, to view explanations for correct answers, or to purchase the complete MKSAP program.

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5 May 2009ITC5-16

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in the clinic abdominal aortic aneurysm · 2016. 7. 19. · aortic aneurysms. lancet....

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