Vascular graft infection

Background

May be extracavitary (in the groin or lower extremities) or intracavitary (in the abdomen or thorax)

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

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 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 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

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

^ 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.