A Nationwide Study on Treatment of Mycotic Abdominal Aortic Aneurysms 1994–2014

Abstract

Introduction: Mycotic (primary infected) aortic aneurysms are rare, life threatening and complex. Current knowledge on treatment is scarce and based on small single-centre case series with heterogenic case-mixes. This nationwide multicentre study aims to assess surgical treatment for mycotic aneurysms of the abdominal aorta (MAAAs). Methods: All patients treated for MAAAs between 1994 and 2014 were identified in the Swedish vascular registry, Swedvasc. All 27 vascular units in Sweden participated in retrieving data and retrospective chart review according to a predefined protocol. Results: 132 patients with 144 MAAAs were identified, constituting 0.6% of all treated abdominal aortic aneurysms (1994–2000 0.2%, 2001–2007 0.6%, and 2008–2014 0.9%). Median age was 70 years (Standard deviation SD 9.2), 91 (69%) were men, 94 (71%) had cardiovascular comorbidity, 51 (39%) were immunosuppressed, and 50 (38%) presented with rupture. The aneurysms were located in the paravisceral aorta in 17 patients (13%), infrarenal 104 (79%), iliac 3 (2%) and multiple aortic segments in 8 (6%). Positive blood culture was obtained in 87 (66%). The three most prevalent infectious agents were Streptococcus sp (n = 28, 21% of all MAAA patients), Staphylococcus aureus (n = 21, 16%), and Salmonella sp (n = 12, 9%). Open repair (OR) was performed in 62 patients (47%); aortic resection and extra-anatomical bypass (n = 7), in-situ reconstruction (n = 50), patch plasty (n = 3); 2 died perioperatively. Endovascular aneurysm repair (EVAR) was performed in 70 (53%), including fenestrated/branched EVAR (n = 8), and hybrid visceral deviation and stentgrafting in (n = 7). EVAR was first introduced in 2001 and has since constituted 60% of all surgery for MAAA. EVAR was performed in 46% of patients presenting with rupture and 57% of those with intact MAAA. 3-months survival improved over time (71% 1994–2000 and 88% 2001–2014), and was better for non-ruptured- compared with ruptured MAAA (93% vs 76%, p = 0.003), and for EVAR compared with OR (96% vs 74%, p < 0.001). Total survival was at 3-months 86% (95% CI 80–92%), 1-year 78% (71–86%), 5-years 59% (50–68%), and 10-years 39% (27–51%). Mean follow-up among survivors (>90-days) was 64 months (range 3–324). Antibiotics were administered for a mean of 29 weeks, range 0–360 weeks. Infection-related death occurred in 22 patients (17%; 23% after OR and 11% after EVAR); 68% occurred within the first year. Reoperation was performed in 30 patients (23%; 22% after OR and 24% after EVAR). Conclusion: In this nationwide analysis of MAAA-treatment over two decades, endovascular approach was increasingly used. This enabled surgical treatment in elderly, comorbid patients, with improved survival at three months without increasing the risk of serious infectious complications or reintervention. Disclosure of Interest: None Declared.