Vascular graft infection: Difference between revisions
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* Radiolabelled WBC scan can be very helpful in distinguishing sterile inflammation from infection and likely has very high sensitivity and specificity |
* Radiolabelled WBC scan can be very helpful in distinguishing sterile inflammation from infection and likely has very high sensitivity and specificity |
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=== Aortic Graft Infection === |
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* There is a [[Aortic graft infection#MAGIC Case Definition|MAGIC Case Definition for AGI]], based on consensus[[CiteRef::lyons2016di]] |
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!Major Criteria |
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!Minor Criteria |
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|Clinical |
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* Pus (confirmed by microscopy) around graft or in aneurysm sac at surgery |
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* Open wound with exposed graft or communicating sinus |
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* Fistula development e.g. aorto-enteric or aorto-bronchial |
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* Graft insertion in an infected site, e.g. fistula, mycotic aneurysm, or infected pseudoaneurysm |
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* Localized clinical features of AGI, e.g. erythema, warmth, swelling, purulent discharge, or pain |
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* Fever ≥38ºC with AGI as most likely cause |
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|Radiologic |
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* Peri-graft fluid on CT scan ≥3 months after insertion |
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* Peri-graft gas on CT scan ≥7 weeks after insertion |
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* Increase in peri-graft gas volume, demonstrated on serial imaging |
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* Other radiographic finding, e.g. suspicious peri-graft gas, fluid, or soft tissue inflammation, aneurysm expansion, pseudoaneurysm formation, focal bowel wall thickening, discitis/osteomyelitis, suspicious metabolic activity on FDG PET/CT, radiolabeled leukocyte uptake |
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|Laboratory |
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* Organisms recovered from an explanted graft |
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* Organisms recovered from an intra-operative specimen |
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* Organisms recovered from a percutaneous, radiologically-guided aspirate or peri-graft fluid |
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* Blood cultures positive and no apparent source except AGI |
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* Abnormally elevated inflammatory markers with AGI as most likely cause, e.g. ESR, CRP, white cell count |
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* Interpretation: |
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** '''Diagnosed AGI:''' one major plus a major or minor criterion from another category |
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** '''Suspected AGI:''' one major, or two minor criteria from different categories |
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==Management== |
==Management== |
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Latest revision as of 17:31, 8 July 2022
Background
- May be extracavitary (in the groin or lower extremities) or intracavitary (in the abdomen or thorax)
Microbiology
- Staphylococcus aureus (30-60%)
- Coagulase-negative staphylococci (10-30%)
- Gram-negative bacilli (10-30%), including Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae
- Viridans group streptococci and enterococci (5%)
- Others: Candida, polymicrobial infections
- Culture-negative (5-30%)
Etiologies
- Intraoperative contamination (most common)
- Contiguous spread from superficial infection or intraabdominal infection
- Direct inoculation during subsequent procedure
- Hematogenous spread, less common after the early postoperative period (first 2 months) due to endothelialization
Clinical Manfestations
- Varies by site of graft and infection
- Can be early-onset (first 2 months) or late-onset (after 2 months)
- Late-onset infections tend to be indolent without sepsis
Samson Classification
- Classification of peripheral arterial prosthetic graft infections 1
- Minor infections
- Group I: infection no deeper than the dermis
- Group II: infection of subcutaneous tissue without visible involvement of graft
- Group III: infections involving graft but not anastomosis
- Group IV: infections involving exposed anastomosis without bacteremia or anastomotic bleeding
- Group V: infections involving graft-to-artery anastomosis with bacteremia or anastomotic bleeding
Diagnosis
- Diagnosis is made clinically
- Ultrasound is usually the initial imaging procedure, followed by CTA or MRI if US is equivocal
- CT- or US-guided aspiration can be helpful for a microbiologic diagnosis
Imaging
- Imaging is a mainstay of diagnosis, and is reviewed in 2
- Ultrasound is typically the first-line choice, and can evaluate perigraft collections as well as guide aspiration
- CT-CTA is the first-line choice for intracavitary infections
- CTA has sensitivity 67% and specificity 63%, but is more sensitive and specific for more complex infections
- Can be hard to distinguish from post-operative changes
- MRI is less well studied, but may be better able to distinguish perigraft fluid from inflammation and fibrosis than CT
- Radiolabelled WBC scan can be very helpful in distinguishing sterile inflammation from infection and likely has very high sensitivity and specificity
Aortic Graft Infection
- There is a MAGIC Case Definition for AGI, based on consensus3
Management
- Local infection without graft involvement: antibiotics with or without incision and drainage (groups I & II)
- Duration 2 to 4 weeks
- Infection involving graft but without bacteremia or anastomotic bleeding (groups III & IV)
- Incision and drainage
- Preservation of graft, or reconstruction with allograft, autograft, or prosthetic material
- 4 to 6 weeks of IV followed by 3 to 6 months of oral
- Infection with bacteremia or anastomotic bleeding (group V)
- Extra-anatomic revascularization followed by graft excision
- 4 to 6 weeks IV followed by 6 months oral
Further Reading
- Vascular Graft Infections, Mycotic Aneurysms, and Endovascular Infections: A Scientific Statement From the American Heart Association. Circulation. 2016;134:e412-e460. doi: 10.1161/CIR.0000000000000457
References
- ^ Russell H. Samson, Frank J. Veith, Gary S. Janko, Sushil K. Gupta, Larry A. Scher. A modified classification and approach to the management of infections involving peripheral arterial prosthetic grafts. Journal of Vascular Surgery. 1988;8(2):147-153. doi:10.1016/0741-5214(88)90402-8.
- ^ Chiara Lauri, Roberto Iezzi, Michele Rossi, Giovanni Tinelli, Simona Sica, Alberto Signore, Alessandro Posa, Alessandro Tanzilli, Chiara Panzera, Maurizio Taurino, Paola Anna Erba, Yamume Tshomba. Imaging Modalities for the Diagnosis of Vascular Graft Infections: A Consensus Paper amongst Different Specialists. Journal of Clinical Medicine. 2020;9(5):1510. doi:10.3390/jcm9051510.
- ^ O.T.A. Lyons, M. Baguneid, T.D. Barwick, R.E. Bell, N. Foster, S. Homer-Vanniasinkam, S. Hopkins, A. Hussain, K. Katsanos, B. Modarai, J.A.T. Sandoe, S. Thomas, N.M. Price. Diagnosis of Aortic Graft Infection: A Case Definition by the Management of Aortic Graft Infection Collaboration (MAGIC). European Journal of Vascular and Endovascular Surgery. 2016;52(6):758-763. doi:10.1016/j.ejvs.2016.09.007.
