1. Joint Hospital Surgical Ground Round 17-7-2010 The Management of Mycotic Aneurysm Chan Hoi Yee Princess Margaret Hospital

2. Mycotic Aneurysm First case was described in 1885 by Osler Dilatation of aorta > 50% of the luminal diameter with signs of infection (biochemical markers or imaging) infective aortic aneurysm, first used in 1975 0.7-2.6% aortic aneurysm are complicated by infection 80% due to microbial arteritis (most commonly caused by Streptococcus and Samonella)

3. Pathogenesis Septic emboli lodged in vessel lumen Inflammatory process outside vessel wall Inoculation of bacteria at time of accidental arterial trauma Self induced vascular manipulation Intimal defect seeded by concurrent bacteremia

4. Mycotic Aneurysm Infected Aortic Aneurysms: Aggressive Presentation, Complicated Early Outcome, but Durable Result. Gustavo S et al. J Vasc Surg 2001;34:900-8

5. Presentation Classic triad: FeverLeukocytosis Pulsatile mass Infected Aortic Aneurysms: Aggressive Presentation, Complicated Early Outcome, but Durable Result. Gustavo S et al. J Vasc Surg 2001;34:900-8 Variables n (N=43) % symptomatic4093 elevated ESR1886 fever3377 Abdominal or back pain2865 Leukocytosis >12.0002354 chills2251 sweats1228 Enlarging aneurysm 1228 GI symptoms (eg. Nausea/vomiting/diarrhea) 1025 rupture921 Pulsatile mass 716 Haemodynamic instablility 37

6. Investigations Infected Aortic Aneurysms: Aggressive Presentation, Complicated Early Outcome, but Durable Result. Gustavo S et al. J Vasc Surg 2001;34:900-8 Organisms Culture obtained from blood (n=32) Culture obtained from aneurysm wall (n=42) Total (N = 43) % Culture positive 25 (78) 27 (64) 33 (77) Staphylococcus710 11 (26) E coli 63 6 (14) Streptococcus43 5 (12) Salmonella44 4 (9) Listeria monocytogenes 01 1 (2) Bacteroides fragilis 01 1 (2) Candida01 Mycobacterium01 H. Influenza 11 1 (2) Clostridium11 Coccidioides immitis 11 1 (2)

7. CT imaging A Comparison of Computed Tomography, Magnetic Resonance Imaging, and Digital Subtraction Angiography Findings in the Diagnosis of Infected Aortic Aneurysm. MP Lin et al. J Comput Assist Tomogr. 2008;32:616-620

8. Imaging

9. Treatment of Mycotic aneurysm Antibiotics vs Antibiotics + surgery

10. Medical Treatment Medical treatment: - more effective antibiotics - more effective antibiotics - surgery carries high risk - surgery carries high risk - salmonella infections: - salmonella infections: iv ceftriaxone 1000-2000gm Q12H iv ceftriaxone 1000-2000gm Q12H - non-salmonella infections: - non-salmonella infections: according to the culture result and according to the culture result and sensitivity test sensitivity test

11. Medical Treatment Selective Medical Treatment of Infected Aneurysms of the Aorta in High Risk Patients. RB Hsu et al. J Vasc Surg 2009;49:66-70 In-hospital Mortality 50% Aneurysm Related Mortality 54.2%

12. Surgical Treatment Aneurysm resection + soft tissue debridement + extra-anatomical bypass (eg. Axillo-bifemoral bypass) Aneurysm resection + debridement + in-situ graft repair Endovascular stenting

13. Combined Medical and Surgical Treatment P= 0.314 Infected Aortic Aneurysm: Clinical Outcome and Risk Factor Analysis. RB. Hsu et al. J Vasc Surg 2004;40:30-5

14. Surgical Treatment Clinical outcomes of 6137 patients who underwent aortic reconstruction for aortic aneurysms at Mayo Clinic between Jan 1976 to Jan 2000 were reviewed 43 patients had mycotic aneurysms underwent aneurysm resection + debridement + extra-anatomic bypass (6) or in-situ aortic graft (35) Operative mortality rate: 21 % ( in-situ repair (20%) vs extra-anatomic bypass (16%) ) ( in-situ repair (20%) vs extra-anatomic bypass (16%) ) Infected Aortic Aneurysms: Aggressive Presentation, Complicated Early Outcome, but Durable Results. Gustavo S et al. J Vasc Surg 2001;34:900-8 Infected Aortic Aneurysms: Aggressive Presentation, Complicated Early Outcome, but Durable Results. Gustavo S et al. J Vasc Surg 2001;34:900-8

15. Surgical Treatment Infected Aortic Aneurysms: Aggressive Presentation, Complicated Early Outcome, but Durable Results. Gustavo S et al. J Vasc Surg 2001;34:900-8 No difference in late graft complication

16. Surgical Treatment Disadvantages for aneurysm resection + debridement + extra-anatomical bypass : - late disruption of aortic stump (20%) due to persistent infection --> fetal - late disruption of aortic stump (20%) due to persistent infection --> fetal - lower limb ischemia required amputation 20-29% - lower limb ischemia required amputation 20-29% - lower patency rates of axillary-femoral bypass (19-50%) - lower patency rates of axillary-femoral bypass (19-50%) - extra-anatomic reconstruction is difficult for thoracoabdominal aneurysms - extra-anatomic reconstruction is difficult for thoracoabdominal aneurysms  Wide debridement of necrotic tissue + copious saline irrigation + in-situ repair with aortic graft  Wide debridement of necrotic tissue + copious saline irrigation + in-situ repair with aortic graft Treatment of infected abdominal aortic aneurysms with extra-anatomic bypass, aneurysm excision and drainage. Taylor LM et al. Am J Surg. 98;155:655-8

17. Surgical Treament Surgical Treatment for Primary Infected Aneurysm of the Descending Thoracic Aorta, Abdominal Aorta and Iliac Arteries.RB Hsu et al. J Vasc Surg 2002;36:746-50 Case No AgeSexFeverPainShockOperation Hospital Outcome Pathogen 178M+-++DeadBacteroides 251M++-+AliveSalmonella 374M+--+AliveSalmonella 458M++++AliveSalmonella 562M+++AliveSalmonella 661F+++AliveSalmonella 754M+++AliveStaphylococcus 872F++++AliveSalmonella 976F+++AliveSalmonella 1071M+++AliveSalmonella 1161F--+AliveStreptococcus 1269F+-+AliveSalmonella 1357M+++AliveSalmonella 1484F-++AliveTuberculosis 1561M+++AliveSalmonella 1661M+++AliveSalmonella 1759M+++AliveSalmonella 1862M+++AliveSalmonella 1985F-+++AliveStreptococcus 2082F+++-Dead E coli 2180M+++-DeadSalmonella 2283M+++-DeadSalmonella 2386M+++-DeadSalmonella 2481M++--Alive Hospital mortality 5%

18. Surgical Treatment No perioperative intestinal ischemia or peri-operative limb loss Survival rate after mean follow-up period of 23.6 months: 84.2 % No patient has graft infection during follow-up period Surgical Treatment for Primary Infected Aneurysm of the Descending Thoracic Aorta, Abdominal Aorta and Iliac Arteries. RB Hsu et al. J Vasc Surg 2002;36:746-50

19. Endovascular Stenting Permanent treatment Bridge to open surgery First report of successful case by Semba et al in 1998 Can avoid: - large incisions - large incisions - aortic clamping - aortic clamping - need for massive blood transfusion - need for massive blood transfusion

20. Endovascular Stenting Disadvantages: - aneurysm is not excised  facilitate re-infection, recurrent sepsis and infection of stent - aneurysm is not excised  facilitate re-infection, recurrent sepsis and infection of stent - no culture can be harvested from wall of aneurysms - no culture can be harvested from wall of aneurysms  could residual infection be overcome by  could residual infection be overcome by antibiotics ??? antibiotics ???  would placement of foreign body in  would placement of foreign body in infective bed aggravate the infection ??? infective bed aggravate the infection ???

21. Endovascular Stenting A retrospective study included 48 patients from Jan 1998 to Jan 2007 with a mean follow-up period of 22 months 30-day mortality rate: 10.4% due to sepsis or massive bleeding Outcome After Endovascular Stent Graft Treatment for Mycotic Aortic Aneurysm: A Systemic Review. DK Chung et al. J Vasc Surg 2007;46:906-12

22. Endovascular Stenting Outcome After Endovascular Stent Graft Treatment for Mycotic Aortic Aneurysm: A Systemic Review. DK Chung et al. J Vasc Surg 2007;46:906-12 age > 65 ruptured aneurysm or fever at presentation 25%

23. Duration of Post-operative antibiotics Not well studied 6-8 weeks to lifelong No signs of infection  - fever subsided - fever subsided - low leukocytes count - low leukocytes count - low titer of CRP - low titer of CRP

24. Conclusions Rare disease Reported hospital mortality rate after combined medical and surgical treatment was 16-44% Classical surgical treatment was aneurysm resection + soft tissue debridement + extra-anatomical bypass In-situ graft repair also showed good results (survival rate 82.4% without graft infection or other complication) EVAR is the new trend of treatment However, all studies only have small case number and results may not show clinically significance Larger study with longer period of follow-up is required

25. References Infected aortic aneurysms: aggressive presentation, complicated early outcome, but durable results. Gustavo S et al. J Vasc Surg 2001;34:900-8 A comparison of computed tomography, magnetic resonance imaging, and digital subtraction angiography findings iin the diagnosis of infected aortic aneurysm. MP Lin et al. J Comput Assist Tomogr 2008;32:616-620 Selective medical treatment of infected aneurysms of the aorta in high risk patients. RB Hsu et al. J Vasc Surg 2009;49:66-70 Surgical treatment for primary infected aneurysm of the descending thoracic aorta, abdominal aorta, and iliac arteries. RB Hsu et al. J Vasc Surg 2002:36;746-50 Infected aortic aneurysm, a changing entity. Mario N. Gomes et al. Ann Surg 1992(5);435-442 Outcome after endovacsular stent graft treatment for mycotic aortic aneurysm: a systemic review. CD Kan et al. J Vasc Surg 2007;46:906-12 Infected aortic aneurysms: clinical outcome and risk factor analysis. RB Hsu et al. J Vasc Surg 2004;40:30-5

26. Thank You