Joint Hospital Surgical Ground Round 17-7-2010

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: • Fever • Leukocytosis • Pulsatile mass Infected Aortic Aneurysms: Aggressive Presentation, Complicated Early Outcome, but Durable Result. Gustavo S et al. J Vasc Surg 2001;34:900-8

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

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 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

9. Treatment of Mycotic aneurysm Antibiotics vs Antibiotics + surgery

10. Medical Treatment • Medical treatment: - more effective antibiotics - surgery carries high risk - salmonella infections: iv ceftriaxone 1000-2000gm Q12H - non-salmonella infections: according to the culture result and 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%) ) 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 - lower limb ischemia required amputation 20-29% - lower patency rates of axillary-femoral bypass (19-50%) - extra-anatomic reconstruction is difficult for thoracoabdominal aneurysms  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 Hospital mortality 5% 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

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 - aortic clamping - need for massive blood transfusion

20. Endovascular Stenting • Disadvantages: - aneurysm is not excised  facilitate re-infection, recurrent sepsis and infection of stent - no culture can be harvested from wall of aneurysms  could residual infection be overcome by antibiotics ???  would placement of foreign body in 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 25% • age > 65 • ruptured aneurysm or fever • at presentation

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