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.
