graft infection

1. COMPLICATION :
GRAFT INFECTION
F2 Parach Sirisriro
15 Jan 2019

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. 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. • 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. OUTLINE
Incidence
Classification
Pathogenesis
Diagnosis
Surgical treatment and Outcome

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. 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. INCIDENCE RELATED IMPLANTATION SITE

9. CLASSIFICATION

10. RELATIONSHIP TO POSTOPERATIVE WOUND INFECTION
(SZILAGYI’S CLASSIFICATION)

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. PATHOGENESIS

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

15. 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

16. 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

17. 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

18. 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

19. 4.INVOLVEMENT BY CONTIGUOUS
INFECTIOUS PROCESS
 An adjacent infection
 Aortofemoral limb infection associated with diverticulitis
 Peripheral graft infection secondary to an infected lymphocele

20. 5. IMPAIR HOST DEFENSE
PATIENT-RELATED FACTORS (ALTERED IMMUNE STATUS)

21. BACTERIOLOGY OF PROSTHETIC VASCULAR GRAFT
INFECTIONS FROM COLLECTED SERIES

22. 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

23. • Gram negative :
1. E.coli
2. Pseudo
3. Klebsiella
4. Enterobacter
5. Serratia
6. Proteus
•  virulent  high anastomosis dehiscence
BACTERIOLOGY

24.  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

25.  Avoid concomitant GI procedure
 Prophylactic antibiotic 30-60 min before
 Longer (>24hr) duration of periprocedural antibiotic
 Control MRSA : disposable gowns , gloves , masks
PREVENTION PRINCIPLE

26. 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

27. 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

28. • 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

29. 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

30. DIAGNOSIS

31. CLINICAL FEATURES

33. 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%

34. • Anatomical imaging
modality
CT scan
Ultrasound
MRI
•Functional imaging
modality
Functional WBC
scanning
Endoscopy
Arteriography
PRE-OPERATIVE GRAFT IMAGING

35. ACCURACY OF IMAGING MODALITY IN VASCULAR
GRAFT INFECTION

36. CT SCAN/ CTA
CT  preferred initial imaging
 best separates luminal
graft, arterial, venous
structures and perigraft tissues

37. 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):

38. 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)

39. 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).

40. 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

41. 3.MRI
• Better able to distinguish between perigraft
fluid and fibrosis

42. 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

43. 5.ENDOSCOPY
• Upper endoscopy : important diagnostic modality for
suspected GEE/GEF

44. 6. ARTERIOGRAPHY
• To define inflow and outflow targets for new bypass in
the presence of occlusive disease or graft thrombosis

45. 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

46. 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

47. SURGICAL
TREATMENT AND
OUTCOMES

48. 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

50. 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

51. 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

52. 1.GRAFT PRESERVATION
• Treatment
1.Serial wound debridement in OR
2.Cytotoxic irrigation + antibiotic-loaded
polymethyl methacrylate (PMMA) beads
3.Definitive skin closure

53. 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

54. 2. GRAFT EXCISION
ONLY
• Occluded septic prosthetic
graft
• No need for
revascularization
• Any organism
• Culture-directed antibiotics
for 7 – 10 day

55. 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

56. 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

57. 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

58. 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

59. 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%.

60. 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

62. OTHER VASCULAR
PROSTHETIC
INFECTIONS

63. 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

64. • Definitive treatment of stent and stent-graft infections,
including aortoenteric erosions explantation of
device and ex situ bypass or in situ
ENDOVASCULAR DEVICE INFECTION

65. 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%

66. CONCLUSION
• Graft infection : Prophylaxis is better than
treatment
• Principle of treatment
1.Accurate diagnosis
2.Antibiotic
3.Intervension : Graft preservation , In
situ , Ex situ

67. THANK YOU