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15 dec 2019 graft infection

graft infection

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15 dec 2019 graft infection

  1. 1. COMPLICATION : GRAFT INFECTION F2 Parach Sirisriro 15 Jan 2019
  2. 2. REFERENCE Textbook 1. Rutherford's Vascular Surgery and Endovascular Therapy 9th edition , Chapter 47, 589-601.e 2. Vascular and Endovascular Surgery: A Companion to Specialist Surgical Practice, 6th Edition , Chapter 7, 83-101.e
  3. 3. REFERENCE Journal - European Journal of Vascular & Endovascular Surgery RSS : Volume 56, Issue 5 , 2018-11- 1, Pages i-767 - Infectious Disease Clinics of North America : Current Issue , 2018-12-1, Volume 32, Issue 4
  4. 4. • Orton, D. F., et al. (2000). "Aortic prosthetic graft infections: radiologic manifestations and implications for management." Radiographics 20(4): 977-993. • Folmer, E. I. R., et al. (2018). "Diagnostic Imaging in Vascular Graft Infection: A Systematic Review and Meta-Analysis." European Journal of Vascular and Endovascular Surgery. • Fatima, J., et al. (2013). "Treatment strategies and outcomes in patients with infected aortic endografts." Journal of vascular surgery 58(2): 371-379. REFERENCE
  5. 5. OUTLINE Incidence Classification Pathogenesis Diagnosis Surgical treatment and Outcome
  6. 6. VASCULAR GRAFT SEPSIS Definition: Sepsis involving all or part of a vascular conduit, vascular patch or endovascular prosthesis • Prosthetic vascular grafts • Endovascular prosthesis (aortic or peripheral) • Autologous vascular grafts / patches (rare)
  7. 7. INCIDENCE • A population-based study from the Mayo Clinic estimated : incidence of infection  5% • Early (<30-day) graft infection  1% • during an emergency procedure (ruptured AAA, acute arterial ischemia) • prosthesis to the femoral artery • placed in a subcutaneous tunnel (axillofemoral or cross-femoral bypass
  8. 8. INCIDENCE RELATED IMPLANTATION SITE
  9. 9. CLASSIFICATION
  10. 10. RELATIONSHIP TO POSTOPERATIVE WOUND INFECTION (SZILAGYI’S CLASSIFICATION)
  11. 11. EXTENT OF GRAFT INVOLVEMENT (BUNT’S CLASSIFICATION) • Peripheral graft infection • • Graft-enteric erosion (GEE) • Graft-enteric fistula (GEF) • Aortic stump sepsis after excision of an infected aortic graft
  12. 12. PATHOGENESIS
  13. 13. CELLULAR AND BIOMOLECULAR EVENTS Biomaterial-associated infection  fundamental steps  Adhesion of bact to graft/stent surface  Formation of microcolonies within biofilm  Activation host defense  Inflammatory response involve perigraft tissue , anastomosis
  14. 14. CLINICAL SOURCES OF INFECTION  Perioperative contamination  Seeding of biomaterial by bacteremia  Mechanical erosion into bowel / genitourinary / skin  Involvement in contiguous infectious process  Impair host defense
  15. 15. 1.PERIOPERATIVE CONTAMINATION  Direct route during implantation ( break aseptic technique)  Through surgical wound ( healing complication: cellulitis , dermal necrosis , lymphocele / gaping) (C/S s.epidermidis 50-70% thrombosed graft , > 80% anastomosis aneurysm)  Hematogenous/lymphatic from remote site
  16. 16. 2.BACTEREMIA  Uncommon but important mechanism  IV Bact 107 within days implantation  100% infection  Parenteral antibiotic  significant decrease risk of graft colonization from bacteremia  Vulnerability graft to infection is beyond 1 yr  Prosthesis heal , incorporated into surrounding tissue  bact colonization decrease
  17. 17. 3.MECHANICAL EROSION  GEE/GEF develop as result of pulsatile movement of aortic graft against bowel without adequate intervening retroperitoneal soft tissue  Incidence GEE/GEF after aortic grafting : 0.4-2% GEF : Graft enteric fistula GEE : Graft enteric erosion
  18. 18. 4.INVOLVEMENT BY CONTIGUOUS INFECTIOUS PROCESS  An adjacent infection  Aortofemoral limb infection associated with diverticulitis  Peripheral graft infection secondary to an infected lymphocele
  19. 19. 5. IMPAIR HOST DEFENSE PATIENT-RELATED FACTORS (ALTERED IMMUNE STATUS)
  20. 20. BACTERIOLOGY OF PROSTHETIC VASCULAR GRAFT INFECTIONS FROM COLLECTED SERIES
  21. 21. BACTERIOLOGY • S. aureus is the most common pathogen 1/4-1/2 of infection • S.epidermidis , Gram –ve increase • Graft culture negative : S.epidermidis , staph coag neg , candida
  22. 22. • Gram negative : 1. E.coli 2. Pseudo 3. Klebsiella 4. Enterobacter 5. Serratia 6. Proteus •  virulent  high anastomosis dehiscence BACTERIOLOGY
  23. 23.  Avoid prolonged pre-op hos stay  Shower , scrub with antibacterial soap night before  Control remote infection  Remove hair immediate before operation  Protect vas graft contact with skin by use of iodine-impregnated plastic drapes PREVENTION PRINCIPLE
  24. 24.  Avoid concomitant GI procedure  Prophylactic antibiotic 30-60 min before  Longer (>24hr) duration of periprocedural antibiotic  Control MRSA : disposable gowns , gloves , masks PREVENTION PRINCIPLE
  25. 25. ANTIBIOTIC PROPHYLAXIS IN ADULTS UNDERGOING VASCULAR PROCEDURES • 1st Vascular intervention (ATB for 24hrs) • Cefalexin 1-2 g iv 30 min before procedure and repeat q 8 hrs • Cefuroxime 1.5 g iv q 12 hrs • Single dose before procedure involving a prior access-site prosthesis (2nd intervention) • Cefalexin 1-2 g iv 30 min before procedure and repeat q 8 hrs • Cefuroxime 1.5 g iv q 12 hrs • Re-op involving an existing prosthesis graft/ patch • Vancomycin 1 g iv 30-60 min before incision and continued q 12 hrs for 24-48 hrs High MRSA risk : Vancomycin 1 g iv before procedure Alternative for penicillin , Cephalosporin or Vancomycin allergy 1. Daptomycin 4 mg/kg and repeat dose 24 hrs 2. Levofloxacin 500 mg iv and repeat dose 24 hrs 3. Clindamycin 900 mg iv and repeat dose 450-900 mg q 8
  26. 26. PROPHYLACTIC ANTIBIOTICS • Additional dose - prolonged procedure (>4 hr) - excessive change blood volume / fluid • Some centers : prophylaxis ATB 2-3 days high risk ( prolonged procedure , high institutional wound infection >10%) > 4 hrs repeat dose ATB
  27. 27. • FOR PREVENT GRAFT COLONIZATION AND TRANSIENT BACTEREMIA : ATB is recommended if intervention ( dental work , colonoscope , cystoscope) performed within 3 mo after implantation of prosthesis graft • Amoxy 2 g oral 1 hr before or Clindamycin 600 mg PROPHYLACTIC ANTIBIOTICS
  28. 28. OPERATIVE CONCERN  Meticulous sterile technique  Avoid bacteria contact of vas devices  Careful handling tissues  Hemostatic technique  Closure groin in multiple layers to eliminate dead space  Skin reapproximate without tension  minimize dermal ischemia / necrosis
  29. 29. DIAGNOSIS
  30. 30. CLINICAL FEATURES
  31. 31. PRE-OPERATIVE GRAFT IMAGING Confirm perigraft inflammation Dilineate the extent of graft sepsis Angiographic imaging is used to plan a strategy for revascularization in presence of distal ischemia , occlusive disease , graft thrombosis  Combination anatomic and functional imaging is fairly accurate:  Navigational tool to plan operative strategies  Imaging-guided fluid aspirate Peri-graft fluid / Peri-graft gas Anastomosis leak Partial vs. total graft involvement GEE/GEF Sensitivity 80-100% Specificity 50-90%
  32. 32. • Anatomical imaging modality CT scan Ultrasound MRI •Functional imaging modality Functional WBC scanning Endoscopy Arteriography PRE-OPERATIVE GRAFT IMAGING
  33. 33. ACCURACY OF IMAGING MODALITY IN VASCULAR GRAFT INFECTION
  34. 34. CT SCAN/ CTA CT  preferred initial imaging  best separates luminal graft, arterial, venous structures and perigraft tissues
  35. 35. DIAGNOSTIC CRITERIA CT scan / CTA • loss of normal tissue planes (fat density) of retroperitoneal or subcutaneous perigraft structures (indicative of inflammation) • collections of fluid or gas (>3 mo after implantation) around the graft • false aneurysm formation • hydronephrosis, and adjacent vertebral or bony osteomyelitis Orton, D. F., et al. (2000). "Aortic prosthetic graft infections: radiologic manifestations and implications for management." Radiographics 20(4):
  36. 36. Figure A , CT scan showing perigraft fluid with air(arrow) Figure B : CT scan showing thickened perigraft tissue (large arrow) and air within the graft and perigraft tissue (small arrow)
  37. 37. Figure C : CT scan showing left limb of aortobifemoral bypass (vertical arrow) surrounded by a large false aneurysm with a small blush of contrast (small arrow). The false aneurysm communicates with a large abscess (*) extending from the retroperitoneum into the left lateral abdominal wall. Note air within the abscess (large arrow). Figure D, CT scan of the right leg showing complex abscess containing air at the infrageniculate level (long arrow).
  38. 38. 2.ULTRASONOGRAPHY • Initial imaging study for extracavitary (P1, P2, P3) graft infections • Color duplex scanning : differentiate a perigraft fluid from • Anastomotic pseudoaneurysm • Hematoma • soft tissue masses
  39. 39. 3.MRI • Better able to distinguish between perigraft fluid and fibrosis
  40. 40. 4. FUNCTIONAL WBC SCANNING • To demonstrate abnormal accumulation of leukocytes in perigraft tissue • The accuracy of indium 111–labeled WBC scans  80-90% in detecting graft infection • Not useful during early postoperative course (3 - 6 mos) because of uptake in the healing, inflamed perigraft tissue
  41. 41. 5.ENDOSCOPY • Upper endoscopy : important diagnostic modality for suspected GEE/GEF
  42. 42. 6. ARTERIOGRAPHY • To define inflow and outflow targets for new bypass in the presence of occlusive disease or graft thrombosis
  43. 43. CT-GUIDED ASPIRATION VS OPERATIVE • CT guided : to differentiate uninfected seroma from abscess formation ( false negative ) • The definitive diagnostic test for suspected graft infection is operative exploration, especially with equivocal anatomic imaging and suspected GEE/GEF • Broth culture of graft material : only reliable method  identifying bacteria and selecting appropriate antibiotic therapy
  44. 44. CULTURE TECHNIQUES • Standard swab cultures directly from the graft surfaces and perigraft fluid are usually sufficient • Surface swabs may not recover less virulent pathogens that do not invade perigraft tissues
  45. 45. SURGICAL TREATMENT AND OUTCOMES
  46. 46. SURGICAL TREATMENT AND OUTCOMES Goals of treatment 1.Eradicate septic process 2.Maintenance of normal arterial perfusion Selection criteria for specific treatment modalities are based primarily on 1. clinical findings 2. extent of graft involvement
  47. 47. TREATMENT ALGORITHMS NEED TO BE PATIENT-SPECIFIC BASED ON CLINICAL FEATURES, EXTENT OF GRAFT INVOLVEMENT AND BACTERIOLOGY 3 Graft preservation technique 2 Graft excision Only 1 -Total Graft excision & Extra- anatomical/ Remote bypass grafting -Graft excision (Total/Partial) & In-situ graft replacement
  48. 48. 1.GRAFT PRESERVATION • Limited circumstances (15-20%candidate  success 70% ) 1.shorter length (segmental) 2.Sparing anastomosis (graft body only) 3.PTFE use 4.Early implantation(<4mo) 5.single gram + 6.extracavity
  49. 49. 1.GRAFT PRESERVATION • Treatment 1.Serial wound debridement in OR 2.Cytotoxic irrigation + antibiotic-loaded polymethyl methacrylate (PMMA) beads 3.Definitive skin closure
  50. 50. Better results with early infection vs. late infection Better results with PTFE vs. Dacron grafts Segmental non-anastomotic graft involvement Any organism (caution with pseudomonas / MRSA) 1.GRAFT PRESERVATION ** Graft sepsis antibiotic protocol: 6 weeks
  51. 51. 2. GRAFT EXCISION ONLY • Occluded septic prosthetic graft • No need for revascularization • Any organism • Culture-directed antibiotics for 7 – 10 day
  52. 52. 3.GRAFT EXCISION AND EXTRA- ANATOMICAL BYPASS • Graft excision alone : arterial collaterals adequate not to develop CLI • Intra-op decision : temporary bypass occlusion 1.Persistence pulsatile pedal pulse AND 2.Ankle pressure >40 mmHg  Delayed revascularization is OK
  53. 53. TIME OF LIMB REVASCULARIZATION - Simultaneous • Unstable patient • Haemorrhage • Severe graft sepsis • GEE / GEF & a widely patent, functioning graft - Staged : axillofemoral PTFE bypass 1-2 days then excision graft • Stable patients • No haemorrhage • Reasonably collateralized, will tolerate interval ischaemia
  54. 54. OUTCOME • Limb loss in infected aortofemoral > aortoiliac reconstruction • Unilateral axillofemoral to profunda or SFA patency 94% at 6 mo • Axillopopliteal bypass patency 42% at 6 mo
  55. 55. 3.IN SITU GRAFT REPLACEMENT • Aortic and / or peripheral grafts • No GEE / GEF • Staph epidermidis or culture negative organisms • No perigraft pus • Biofilm infection • Segmental or total graft involvement
  56. 56. ANTIBIOTIC-TREATED PROSTHETIC GRAFTS • In situ prosthetic with PTFE or polyester  recurrent infection 10-20% • > 50% of late extracavitary graft infections met these criteria + treated in situ PTFE  reinfection rate < 5%.
  57. 57. SELECTION CRITERIA FOR IN SITU WITH PROSTHETIC GRAFT Clinical 1. Months to years after implantation 2. No systemic signs Anatomical 1. Limited local inflammation 2. Perigraft cavity with absence of graft incorporation 3. Weakening of anastomosis Microbiology 1. Perigraft fluid : Gram stain negative 2. Perigraft fluid : Culture no growth 3. Graft biofilm culture : coag - staph
  58. 58. OTHER VASCULAR PROSTHETIC INFECTIONS
  59. 59. ENDOVASCULAR DEVICE INFECTION • The incidence infection endoluminal devices is lower than prosthetic grafts during open surgical procedures • Both arterial stents and stent-grafts show decreasing susceptibility by 1-4 wks to bacteremic as a result of protective pseudointimal healing
  60. 60. • Definitive treatment of stent and stent-graft infections, including aortoenteric erosions explantation of device and ex situ bypass or in situ ENDOVASCULAR DEVICE INFECTION
  61. 61. THORACIC AORTIC AND SUPRA-AORTIC BRANCH PROSTHETIC INFECTIONS • Graft excision and extra-anatomic bypass are not possible for most cases of ascending, transverse arch, or descending thoracic aortic graft infection • Mortality : 10-20% in major tertiary centers, recurrent/residual infection 20%
  62. 62. CONCLUSION • Graft infection : Prophylaxis is better than treatment • Principle of treatment 1.Accurate diagnosis 2.Antibiotic 3.Intervension : Graft preservation , In situ , Ex situ
  63. 63. THANK YOU

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