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Infective Native Aortic Aneurysms: Call for Consensus on Definition, Terminology, Diagnostic Criteria, and Reporting Standards

2020; Elsevier BV; Volume: 59; Issue: 3 Linguagem: Inglês

10.1016/j.ejvs.2019.11.008

1532-2165

Karl Sörelius, Anders Wanhainen, Kevin Mani,

Vascular Procedures and Complications

There is no consensus in the literature regarding the definition, terminology, classification, or diagnostic criteria for aortic aneurysms due to infection, commonly known as mycotic aortic aneurysms (MAAs).1Sörelius K. Mani K. Budtz-Lily J. Wanhainen A. Systematic review on the management of mycotic aortic aneurysms.Eur J Vasc Endovasc Surg. 2019; 58: 426-435Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar,2Wanhainen A. Verzini F. van Herzele I. Allaire E. Bown M.J. Cohnert T. et al.European Society for Vascular Surgery (ESVS) 2019 clinical practice guidelines on the management of abdominal aorto-iliac artery aneurysms.Eur J Vasc Endovasc Surg. 2019; 57: 8-93Abstract Full Text Full Text PDF PubMed Scopus (632) Google Scholar In a recently published systematic literature review it became evident that the lack of standardised definitions results in significant diversity in the literature and hampers research on this disease.1Sörelius K. Mani K. Budtz-Lily J. Wanhainen A. Systematic review on the management of mycotic aortic aneurysms.Eur J Vasc Endovasc Surg. 2019; 58: 426-435Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar The European Society for Vascular Surgery (ESVS) 2019 guidelines on abdominal aortic aneurysms state that the term mycotic is misleading, a historical misnomer indicating a fungal genesis rather than bacterial, and recommend that the diagnostic work up should consist of a combination of: (i) clinical presentation; (ii) laboratory results; and (iii) imaging, as there is no pathognomonic symptom or test for the disease.2Wanhainen A. Verzini F. van Herzele I. Allaire E. Bown M.J. Cohnert T. et al.European Society for Vascular Surgery (ESVS) 2019 clinical practice guidelines on the management of abdominal aorto-iliac artery aneurysms.Eur J Vasc Endovasc Surg. 2019; 57: 8-93Abstract Full Text Full Text PDF PubMed Scopus (632) Google Scholar This recommendation was based on recent publications on the subject. Because of the rarity and heterogeneity of the presentation of this disease, coupled with current disparate descriptions in publications, reporting standards are needed to provide uniformity of definitions and classifications for comparative purposes. A consensus document regarding these issues is highly warranted, and would tentatively be addressed by the Delphi method. Such a document should also address aortic graft infections and aorto-enteric fistulas. It might be difficult to define one infectious disease involving the aorta without the others. The recently published ESVS guidelines on vascular graft and stent graft infections is a valuable, encouraging step in the right direction.3Chakfe N. Diener H. Lejay A. Assadian O. Berard X. Caillon J. et al.European Society for Vascular Surgery (ESVS) 2020 clinical practice guidelines on the management of vascular graft and endograft infections.Eur J Vasc Endovasc Surg. 2020; 59: 339-384Abstract Full Text Full Text PDF PubMed Scopus (75) Google Scholar Awaiting such consensus, and based on the findings in the aforementioned systematic review reflecting today's knowledge of MAAs, we here propose a provisional definition, revised terminology, and classification, as well as diagnostic criteria. This editorial also proposes reporting items to enhance comparability of future research on the disease. The terminology may not only include the already existing “mycotic aortic aneurysm” and “infected aortic aneurysms”, but also a new and more correct term infective native aortic aneurysm, INAA (in analogy with infective endocarditis). All three are suggested to be used synonymously. The definition of INAA is an aortic aneurysm, which is caused by microbial infection of the aortic wall. The infection causes degradation of the vessel wall, resulting in formation of a localised aneurysm. The microbial infection is predominantly bacterial, but may also be fungal, or possibly viral in patients with advanced human immunodeficiency virus (HIV) infection. An aorta with extensive atherosclerosis, or a pre-existing aneurysm, is susceptible to such infection. The common definition of degenerative aortic aneurysm based on diameter is not applicable to these aneurysms because the morphology is predominantly saccular, multilobular, or amorphous. Hence, other infective states involving the aorta such as aortic graft infections and secondary aorto-enteric/bronchial fistulas are not part of this disease entity. Classification and subgroups of various infective native aneurysms should, preferably, be done according to this new modification of the one published by Wilson et al. in 19784Wilson S.E. Van Wagenen P. Passaro Jr., E. Arterial infection.Curr Probl Surg. 1978; 15: 1-89Crossref PubMed Scopus (97) Google Scholar: (A) INAAs may develop as a result of septic emboli lodging in the aortic wall from infective endocarditis; (B) blood borne bacteria inoculated in the aortic wall during bacteraemia; (C) infection of a pre-existing aneurysm due to blood borne bacteria; and (D) aneurysms developing in patients with advanced HIV infection. The diagnostic criteria should consist of a combination of clinical criteria: (i) clinical presentation; (ii) laboratory results; and (iii) imaging, as suggested by the ESVS guidelines.2Wanhainen A. Verzini F. van Herzele I. Allaire E. Bown M.J. Cohnert T. et al.European Society for Vascular Surgery (ESVS) 2019 clinical practice guidelines on the management of abdominal aorto-iliac artery aneurysms.Eur J Vasc Endovasc Surg. 2019; 57: 8-93Abstract Full Text Full Text PDF PubMed Scopus (632) Google Scholar A positive culture is not a requisite, if typical clinical presentation and radiological signs are present. In case of open surgery, intra-operative findings might be sufficient to make the diagnosis alone. The proposed algorithm is shown in Box 1.Box 1Proposed algorithmClinical criteria:•definite diagnosis: 3/3 criteria and no differential diagnosis being more likely;•probable diagnosis: 2/3 criteria and no differential diagnosis being more likely;•not probable diagnosis: 1/3 clinical criteria.Pathological criteria:•intra-operative finding of pus/abscess in the aneurysm wall, or positive culture or histology from aneurysms with clinical suspicion of infective native aortic aneurysm (definite or probable INAA). Clinical criteria:•definite diagnosis: 3/3 criteria and no differential diagnosis being more likely;•probable diagnosis: 2/3 criteria and no differential diagnosis being more likely;•not probable diagnosis: 1/3 clinical criteria. Pathological criteria:•intra-operative finding of pus/abscess in the aneurysm wall, or positive culture or histology from aneurysms with clinical suspicion of infective native aortic aneurysm (definite or probable INAA). Reporting items to be included in research on INAAs to enhance comparability between studies, and make meta-analysis possible are shown in Box 2.Box 2Reporting items to be included in research on infective native aortic aneurysms to enhance comparability between studies, and make meta-analysis possible•Use of the above accounted terminology, definition, classification, and diagnostic criteria.•Criteria of exclusion (e.g., aortic graft infections, secondary aorto-enteric fistulae, inflammatory aneurysms).•Patient characteristics (medical history: e.g., cardiopulmonary disease, immunosuppressive state/medication; data on presentation: symptoms, concurrent infection).•Laboratory results (inflammatory markers: C reactive protein, leukocyte levels, cultures from blood/tissues, results of polymerase chain reaction for identification of bacteria).•Imaging findings (aneurysm morphology, e.g., saccular or fusiform, rapid expansion, peri-aortic gas, peri-aortic soft tissue mass) and imaging modality (computed tomography, magnetic resonance imaging, positron emission tomography).•Aneurysm anatomy (level of aorta engaged).•Details on treatment (open repair; in situ bypass or extra-anatomical bypass and graft material; endovascular aortic repair; type of stent graft, hybrid procedure).•Details of antibiotic treatment (pre- and postoperative duration and drug).•Follow up (duration, symptoms, laboratory results, imaging modality and results, outcome, bacteriology in case of infection related complication, re-operations). •Use of the above accounted terminology, definition, classification, and diagnostic criteria.•Criteria of exclusion (e.g., aortic graft infections, secondary aorto-enteric fistulae, inflammatory aneurysms).•Patient characteristics (medical history: e.g., cardiopulmonary disease, immunosuppressive state/medication; data on presentation: symptoms, concurrent infection).•Laboratory results (inflammatory markers: C reactive protein, leukocyte levels, cultures from blood/tissues, results of polymerase chain reaction for identification of bacteria).•Imaging findings (aneurysm morphology, e.g., saccular or fusiform, rapid expansion, peri-aortic gas, peri-aortic soft tissue mass) and imaging modality (computed tomography, magnetic resonance imaging, positron emission tomography).•Aneurysm anatomy (level of aorta engaged).•Details on treatment (open repair; in situ bypass or extra-anatomical bypass and graft material; endovascular aortic repair; type of stent graft, hybrid procedure).•Details of antibiotic treatment (pre- and postoperative duration and drug).•Follow up (duration, symptoms, laboratory results, imaging modality and results, outcome, bacteriology in case of infection related complication, re-operations). Further, it is recognised that these propositions will need future amendments in accordance with newly acquired knowledge in the field. The study of rare vascular pathologies, such as INAAs, is dependent on reports, which would preferentially involve multicentre collaborations, and which adhere to common reporting standards. Homogenous reporting standards enable amalgamation of data from different publications into systematic reviews and meta-analyses, which can create a credible source for evaluation and comparison of outcome with different treatment strategies. This document includes a suggestion for homogenised reporting standards for the treatment of INAAs.