Subscribe for unlimited access to DynaMed content, CME/CE & MOC credit, and email alerts on content you follow.

Already subscribed? Sign in now

Learn more about CME

Abdominal Aortic Aneurysm (AAA)

MoreVert
AddCircleOutlineFollow
ShareShare
AddCircleOutlineFollow
Follow
ShareShare
Share

General Information

Description

  • abnormal irreversible full-thickness dilation of abdominal aorta resulting in diameter ≥ 3 cm or exceeding normal vessel diameter by > 50%1,4 )4
  • definition of aortic diameter ≥ 3 cm may not be appropriate for women who have smaller diameter arteries than men or for patients with arteriomegaly1
  • aneurysms may be classified as small or large
    • small aneurysm typically defined as aortic diameter < 5.5 cm, but may sometimes be defined as 3-4.9 cm (30-49 mm) or 3-5.5 cm (30-55 mm)1,3
    • large aneurysm typically defined as ≥ 5.5 cm (55 mm)1

Also called

  • atherosclerotic aortic aneurysm
  • aortic aneurysm

Definitions

  • normal adult abdominal aortic diameters
    • varies based on age, sex, body size, and blood pressure3
    • infrarenal aortic diameter of 2.7 cm (27 mm) represents 95th percentile for men aged 65-83 years2
    • normal aortic diameters slightly smaller in women than men, but differences in diameter not great enough to influence definition of abdominal aneurysm2
    • normal abdominal aorta diameters based on sex2
       Supraceliac Abdominal Aorta Suprarenal Abdominal Aorta Infrarenal Abdominal Aorta Infrarenal Abdominal Aorta
      Measurement methodComputed tomographyComputed tomographyComputed tomography, IV arteriographyB-mode ultrasound, computed tomography, IV arteriography
      Female mean diameter2.1-2.31 cm (21-23.1 mm)1.86-1.88 cm (18.6-18.8 mm)1.66-2.16 cm (16.6-21.6 mm)1.19-1.87 cm (11.9-18.7 mm)
      Female standard deviation0.27 cm (27 mm)0.09-0.21 cm (0.9-2.1 mm)0.22-0.32 cm (2.2-3.2 mm)0.09-0.34 cm (0.9-3.4 mm)
      Male mean diameter2.5-2.72 cm (25-27.2 mm)1.98-2.27 cm (19.8-22.7 mm)1.99-2.39 cm (19.9-23.9 mm)1.41-2.05 cm (14.1-20.5 mm)
      Male standard deviation0.24-0.35 cm (24-35 mm)0.19-0.23 cm (1.9-2.3 mm)0.3-0.39 cm (3-3.9 mm)0.04-0.37 cm (0.4-3.7 mm)
  • true aneurysm defined as dilation of artery that involves all 3 layers of artery wall (intima, media, and adventitia)1
  • false aneurysm (also called pseudoaneurysm)1
    • defined as dilation secondary to arterial injury and without dilation of all 3 layers but with outer wall lacking organized vascular structure
    • may also occur due to infiltration of blood through dissection at level of medial layer
  • ectatic aorta (also called aortic ectasia or subaneurysmal aorta) defined as abdominal aortic diameter of 2.5-2.9 cm (mnh25884861pcxh101987981pmdc25884861pAm Fam Physician 2015 Apr 15;91(8):538OpenInNewfull-textOpenInNew)

Types

  • type by location of aneurysm4
    • infrarenal (most common) occurs below the renal arteries
    • suprarenal occurs above the renal arteries and involves origin of ≥ 1 visceral arteries
    • pararenal involves origins of renal arteries
    • juxtarenal involves origin distal (but very close to) renal arteries2
  • type by morphology1
    • fusiform (most common) - dilation involves whole circumference of artery
    • saccular - dilation only parts of circumference
  • "atherosclerotic" or nonspecific aneurysm is most common type and may be related to overproduction of proteases such as matrix metalloproteinase MMP-22
  • congenital aneurysm1,2
    • abdominal aortic aneurysm (AAA) may be more frequent in individuals with genetic predisposition to connective tissue disorders
    • syndromes with genetic predisposition to AAA
  • false aneurysms may be secondary to arterial injury such as inflammatory aneurysm or infectious ("mycotic") aneurysm

References

General references used

  1. Sakalihasan N, Michel JB, Katsargyris A, Kuivaniemi H, Defraigne JO, Nchimi A, Powell JT, Yoshimura K, Hultgren R. Abdominal aortic aneurysms. Nat Rev Dis Primers. 2018 Oct 18;4(1):34OpenInNew
  2. Hirsch AT, Haskal ZJ, Hertzer NR, et al; ACC/AHA 2005 Practice Guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic): a collaborative report from the American Association for Vascular Surgery/Society for Vascular Surgery, Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients With Peripheral Arterial Disease): endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation; National Heart, Lung, and Blood Institute; Society for Vascular Nursing; TransAtlantic Inter-Society Consensus; and Vascular Disease Foundation. Circulation. 2006 Mar 21;113(11):e463-654OpenInNewPDFPictureAsPdf
  3. Erbel R, Aboyans V, Boileau C, et al. ESC Committee for Practice Guidelines. 2014 ESC Guidelines on the diagnosis and treatment of aortic diseases: Document covering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adult. The Task Force for the Diagnosis and Treatment of Aortic Diseases of the European Society of Cardiology (ESC). Eur Heart J. 2014 Nov 1;35(41):2873-926OpenInNewfull-textOpenInNew
  4. Kent KC. Clinical practice. Abdominal aortic aneurysms. N Engl J Med. 2014 Nov 27;371(22):2101-8OpenInNew
  5. Chaikof EL, Dalman RL, Eskandari MK, Jackson BM, Lee WA, Mansour MA, Mastracci TM, Mell M, Murad MH, Nguyen LL, Oderich GS, Patel MS, Schermerhorn ML, Starnes BW. The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. J Vasc Surg. 2018 Jan;67(1):2-77.e2OpenInNew

Recommendation grading systems used

  • American College of Cardiology Foundation/American Heart Association (ACCF/AHA) grading system for recommendations
    • classifications of recommendations
      • Class I - procedure or treatment should be performed or administered
      • Class IIa - reasonable to perform procedure or administer treatment, but additional studies with focused objectives needed
      • Class IIb - procedure or treatment may be considered; additional studies with broad objectives needed, additional registry data would be useful
      • Class III - procedure or treatment should not be performed or administered because it is not helpful or may be harmful
        • Class III ratings may be subclassified as Class III No Benefit or Class III Harm
    • levels of evidence
      • Level A - data derived from multiple randomized clinical trials or meta-analyses
      • Level B - data derived from single randomized trial or nonrandomized studies
      • Level C - only expert opinion, case studies, or standard of care
  • United States Preventive Services Task Force (USPSTF) grades of recommendation (prior to May 2007)
    • Grade A - USPSTF strongly recommends that clinicians provide the service to eligible patients, based on good evidence that the service improves important health outcomes and that benefits substantially outweigh harms
    • Grade B - USPSTF recommends that clinicians provide the service to eligible patients, based on at least fair evidence that the service improves important health outcomes and that benefits outweigh harms
    • Grade C - USPSTF makes no recommendation for or against routinely providing the service, based on at least fair evidence that the service can improve health outcomes but the balance of benefits and harms is too close to justify a general recommendation
    • Grade D - USPSTF recommends against routinely providing the service to asymptomatic patients, based on at least fair evidence that the service is ineffective or that harms outweigh benefits
    • Grade I - USPSTF concludes that the evidence is insufficient to recommend for or against routinely providing the service
    • Reference - USPSTF Grade DefinitionsOpenInNew
  • European Society of Cardiology (ESC) grading system for recommendations
    • classes of recommendations
      • Class I - evidence and/or general agreement that given treatment or procedure is beneficial, useful, and effective
      • Class II - conflicting evidence and/or divergence of opinion about usefulness/efficacy of given treatment or procedure
        • Class IIa - weight of evidence/opinion in favor of usefulness/efficacy
        • Class IIb - usefulness/efficacy less well established by evidence/opinion
      • Class III - evidence or general agreement that given treatment or procedure is not useful/effective, and in some cases may be harmful
    • levels of evidence
      • Level A - data derived from multiple randomized clinical trials or meta-analyses
      • Level B - data derived from single randomized trial or large nonrandomized studies
      • Level C - consensus of opinion of experts and/or small studies, retrospective studies, registries
    • Reference - ESC guideline on diagnosis and treatment of aortic diseases: document covering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adult (25173340Eur Heart J 2014 Nov 1;35(41):2873OpenInNew)
  • Society for Vascular Surgery (SVS) grading system for recommendations
    • strength of recommendation
      • GRADE 1 - strong recommendation; high confidence that benefit clearly outweighs risk
      • GRADE 2 - weak recommendation; benefit and risk closely balanced
    • levels of evidence
      • Level A - high-quality evidence; further study unlikely to change conclusions
      • Level B - moderate-quality evidence; further study likely to affect conclusions
      • Level C - low-quality evidence; further study very likely to change conclusions

Synthesized Recommendation Grading System for DynaMed

  • DynaMed systematically monitors clinical evidence to continuously provide a synthesis of the most valid relevant evidence to support clinical decision-making (see 7-Step Evidence-Based MethodologyOpenInNew).
  • Guideline recommendations summarized in the body of a DynaMed topic are provided with the recommendation grading system used in the original guideline(s), and allow DynaMed users to quickly see where guidelines agree and where guidelines differ from each other and from the current evidence.
  • In DynaMed (DM), we synthesize the current evidence, current guidelines from leading authorities, and clinical expertise to provide recommendations to support clinical decision-making in the Overview & Recommendations section.
  • We use the Grading of Recommendations Assessment, Development and Evaluation (GRADE)OpenInNew to classify synthesized recommendations as Strong or Weak.
    • Strong recommendations are used when, based on the available evidence, clinicians (without conflicts of interest) consistently have a high degree of confidence that the desirable consequences (health benefits, decreased costs and burdens) outweigh the undesirable consequences (harms, costs, burdens).
    • Weak recommendations are used when, based on the available evidence, clinicians believe that desirable and undesirable consequences are finely balanced, or appreciable uncertainty exists about the magnitude of expected consequences (benefits and harms). Weak recommendations are used when clinicians disagree in judgments of relative benefit and harm, or have limited confidence in their judgments. Weak recommendations are also used when the range of patient values and preferences suggests that informed patients are likely to make different choices.
  • DynaMed (DM) synthesized recommendations (in the Overview & Recommendations section) are determined with a systematic methodology:
    • Recommendations are initially drafted by clinical editors (including ≥ 1 with methodological expertise and ≥ 1 with content domain expertise) aware of the best current evidence for benefits and harms, and the recommendations from guidelines.
    • Recommendations are phrased to match the strength of recommendation. Strong recommendations use "should do" phrasing, or phrasing implying an expectation to perform the recommended action for most patients. Weak recommendations use "consider" or "suggested" phrasing.
    • Recommendations are explicitly labeled as Strong recommendations or Weak recommendations when a qualified group has explicitly deliberated on making such a recommendation. Group deliberation may occur during guideline development. When group deliberation occurs through DynaMed-initiated groups:
      • Clinical questions will be formulated using the PICO (Population, Intervention, Comparison, Outcome) framework for all outcomes of interest specific to the recommendation to be developed.
      • Systematic searches will be conducted for any clinical questions where systematic searches were not already completed through DynaMed content development.
      • Evidence will be summarized for recommendation panel review including for each outcome, the relative importance of the outcome, the estimated effects comparing intervention and comparison, the sample size, and the overall quality rating for the body of evidence.
      • Recommendation panel members will be selected to include at least 3 members that together have sufficient clinical expertise for the subject(s) pertinent to the recommendation, methodological expertise for the evidence being considered, and experience with guideline development.
      • All recommendation panel members must disclose any potential conflicts of interest (professional, intellectual, and financial), and will not be included for the specific panel if a significant conflict exists for the recommendation in question.
      • Panel members will make Strong recommendations if and only if there is consistent agreement in a high confidence in the likelihood that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. Panel members will make Weak recommendations if there is limited confidence (or inconsistent assessment or dissenting opinions) that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. No recommendation will be made if there is insufficient confidence to make a recommendation.
      • All steps in this process (including evidence summaries which were shared with the panel, and identification of panel members) will be transparent and accessible in support of the recommendation.
    • Recommendations are verified by ≥ 1 editor with methodological expertise, not involved in recommendation drafting or development, with explicit confirmation that Strong recommendations are adequately supported.
    • Recommendations are published only after consensus is established with agreement in phrasing and strength of recommendation by all editors.
    • If consensus cannot be reached then the recommendation can be published with a notation of "dissenting commentary" and the dissenting commentary is included in the topic details.
    • If recommendations are questioned during peer review or post publication by a qualified individual, or reevaluation is warranted based on new information detected through systematic literature surveillance, the recommendation is subject to additional internal review.

DynaMed Editorial Process

Special acknowledgements

  • The American College of Physicians (Marjorie Lazoff, MD, FACP; ACP Deputy Editor, Clinical Decision Resource) provided review in a collaborative effort to ensure DynaMed provides the most valid and clinically relevant information in internal medicine.
Choosing Wisely Canada acknowledges dissemination of their recommendations through DynaMed Plus to reach the point of clinical decision-making.
  • DynaMed topics are written and edited through the collaborative efforts of the above individuals. Deputy Editors, Section Editors, and Topic Editors are active in clinical or academic medical practice. Recommendations Editors are actively involved in development and/or evaluation of guidelines.
  • Editorial Team role definitions
    Topic Editors define the scope and focus of each topic by formulating a set of clinical questions and suggesting important guidelines, clinical trials, and other data to be addressed within each topic. Topic Editors also serve as consultants for the internal DynaMed Editorial Team during the writing and editing process, and review the final topic drafts prior to publication.
    Section Editors have similar responsibilities to Topic Editors but have a broader role that includes the review of multiple topics, oversight of Topic Editors, and systematic surveillance of the medical literature.
    Recommendations Editors provide explicit review of DynaMed Overview and Recommendations sections to ensure that all recommendations are sound, supported, and evidence-based. This process is described in "Synthesized Recommendation Grading."
    Deputy Editors are employees of DynaMed and oversee DynaMed internal publishing groups. Each is responsible for all content published within that group, including supervising topic development at all stages of the writing and editing process, final review of all topics prior to publication, and direction of an internal team.

How to cite

National Library of Medicine, or "Vancouver style" (International Committee of Medical Journal Editors):

  • DynaMed [Internet]. Ipswich (MA): EBSCO Information Services. 1995 - . Record No. T114361, Abdominal Aortic Aneurysm (AAA); [updated 2018 Nov 30, cited place cited date here]. Available from https://www.dynamed.com/topics/dmp~AN~T114361. Registration and login required.
  • KeyboardArrowRight

    Overview and Recommendations

    • Background

    • Evaluation

    • KeyboardArrowRight

      Management

      • Medical management with serial monitoring

      • Open surgical or endovascular repair

      • Additional measures

  • Related Summaries

  • KeyboardArrowRight

    General Information

    • Description

    • Also called

    • Definitions

    • Types

  • KeyboardArrowRight

    Epidemiology

    • Who is most affected

    • Incidence/Prevalence

    • Risk factors

    • Factors associated with decreased risk

    • Associated conditions

  • KeyboardArrowRight

    Etiology and Pathogenesis

    • Causes

    • Pathogenesis

  • KeyboardArrowRight

    History and Physical

    • Clinical presentation

    • KeyboardArrowRight

      History

      • History of present illness (HPI)

      • Past medical history (PMH)

      • Family history (FH)

      • Social history (SH)

    • KeyboardArrowRight

      Physical

      • General physical

      • Abdomen

  • KeyboardArrowRight

    Diagnosis

    • Making the diagnosis

    • Differential diagnosis

    • Testing overview

    • Blood tests

    • KeyboardArrowRight

      Imaging studies

      • Approach to imaging aorta and selecting imaging modality

      • Abdominal ultrasound

      • Computed tomography (CT)

      • Magnetic resonance imaging (MRI)

      • X-ray

      • Reviews of imaging

  • KeyboardArrowRight

    Management

    • Management overview

    • KeyboardArrowRight

      Medications

      • Medication treatment in general

      • Beta blockers

      • ACE inhibitors

      • Antibiotics

      • Statins

      • NSAIDs

      • Other medications

    • KeyboardArrowRight

      Surgery and procedures

      • Emergency AAA repair

      • KeyboardArrowRight

        Elective AAA repair

        • Indications and method selection

        • Surgical repair vs. ultrasound monitoring

        • Endovascular vs. open repair

        • Endovascular repair vs. no intervention

        • Endovascular aneurysm sealing (EVAS)

      • KeyboardArrowRight

        Perioperative management

        • Perioperative cardiac management

        • Antimicrobial prophylaxis

        • IV fluids

        • Nasogastric decompression

        • Aortic clamping

        • Analgesia

        • Corticosteroids

        • Transfusion

        • Metformin

        • Beta-blockers

        • Medications to reduce risk for renal dysfunction

        • Hemodynamic monitoring

        • Other preoperative considerations

        • Other postoperative considerations

      • KeyboardArrowRight

        Variations in surgical approaches

        • Open surgical repair approaches

        • Endovascular approaches

      • Surgical complications considerations

    • Other management

    • KeyboardArrowRight

      Follow-up

      • General considerations for imaging aorta and selecting imaging modality for repetitive imaging

      • Aneurysm monitoring

      • Medication during surveillance after AAA repair

      • Monitoring after endovascular AAA repair

  • KeyboardArrowRight

    Complications and Prognosis

    • Complications

    • KeyboardArrowRight

      Prognosis

      • AAA expansion rate

      • Risk for rupture

      • Aneurysmal sac shrinkage after endovascular repair

      • Predicting postoperative hospital readmission or reintervention

      • Predicting postoperative mortality

      • Predicting long-term mortality

  • KeyboardArrowRight

    Prevention and Screening

    • Screening

  • KeyboardArrowRight

    Quality Improvement

    • Physician Quality Reporting System Quality Measures

    • Choosing Wisely Canada

  • KeyboardArrowRight

    Guidelines and Resources

    • KeyboardArrowRight

      Guidelines

      • International guidelines

      • United States guidelines

      • United Kingdom guidelines

      • Canadian guidelines

      • European guidelines

      • Asian guidelines

      • Central and South American guidelines

    • Review articles

    • MEDLINE search

  • Patient Information

  • KeyboardArrowRight

    ICD Codes

    • ICD-10 codes

  • KeyboardArrowRight

    References

    • General references used

    • Recommendation grading systems used

    • Synthesized Recommendation Grading System for DynaMed

    • DynaMed Editorial Process

    • Special acknowledgements

    • How to cite

Topic Editor
Jinnette Dawn Abbott MD, FACC, FSCAI
KeyboardArrowDown
Affiliations

Professor of Medicine, Brown University; Rhode Island, United States; Director of Interventional Cardiology, Rhode Island Hospital, Miriam Hospital; Rhode Island, United States

Conflicts of Interest

Dr. Abbott declares no relevant financial conflicts of interest.

Topic Editor
Maria Sciammarella MD
KeyboardArrowDown
Affiliations

Associate Clinical Professor, University of California, San Francisco; California, United States

Conflicts of Interest

Dr. Sciammarella declares no relevant financial conflicts of interest.

Recommendations Editor
Esther Jolanda van Zuuren MD
KeyboardArrowDown
Affiliations

Head of Allergy, Dermatology, and Venereology, Leiden University Medical Centre; Netherlands

Conflicts of Interest

Dr. van Zuuren declares no relevant financial conflicts of interest.

Deputy Editor
Peter Oettgen MD
KeyboardArrowDown
Affiliations

Editor in Chief, DynaMed; Cardiologist, Beth Israel Deaconess Medical Center; Massachusetts, United States; Associate Professor of Medicine, Harvard Medical School; Massachusetts, United States

Conflicts of Interest

Dr. Oettgen declares no relevant financial conflicts of interest.

Produced in collaboration with American College of Physicians

Images in topic (1)

View all
Abdominal aortic aneurysm

Abdominal aortic aneurysm

CheckCircle
Subscribe for unlimited access to DynaMed content.
Already subscribed? Sign in

top