Background: Radical open surgery (OR) is considered gold standard for management of mycotic abdominal aortic aneurysms (MAAAs). Endovascular repair (EVAR) is a less invasive but controversial treatment option for MAAA because the stentgraft is implanted in an infected field, whilst recent reports indicate promising outcome. No reliable comparative data exists. This nationwide study assesses outcome after OR and EVAR for MAAA in a population-based cohort.
Methods: All patients treated in Sweden for MAAAs 1994-2014 were identified in the Swedish vascular registry. Twenty-seven vascular units participated in data collection according to a predefined protocol. Survival was cross-matched with the population registry.
Results: 132 patients with 144 MAAAs were identified, (0.6% of all operated AAA in Sweden). Median age was 70 years (SD 9.2), 51 were immunosuppressed, and 50 presented with rupture. Survival at 3-months was 86% (95% CI 80-92%), 1-year 79% (72-86%), and 5- years 59% (50-68%).
The preferred operative technique shifted from OR to EVAR after 2001 (proportion EVAR 1994-2000 0%, 2001-2007 58%, 2008-2014 60%). Open repair was performed in 62 patients (47%); aortic resection and extra-anatomical bypass (n=7), in-situ reconstruction (n=50), patch plasty (n=3), and two died intraoperatively OR attempt. EVAR was performed in 70 patients (53%); standard EVAR (n=55), fenestrated/branched EVAR (n=8), and visceral deviation with stentgrafting (n=7).
Survival at 3-months was inferior for OR compared to EVAR in Kaplan-Meier analysis (74% vs 96%, p<0.001), with a similar trend present at 1-year (73% vs 84%, p=0.054). A propensity score weighted risk-adjusted analysis confirmed the early survival benefit of EVAR. During follow-up (median OR 36, EVAR 41 months) there was no difference in long- term survival (5-years 60 vs 58%, p=0.771), infection-related complications (18 vs 24%, p=0.439), or reoperation (21% vs 24%, p=0.650). In a multivariable analysis OR was a significant risk factor for death at 3-months (odds ratio 6.96, p=0.004).
Conclusion: This study demonstrates a paradigm shift in treatment of MAAA in Sweden, with EVAR being the preferred treatment modality. EVAR achieved improved short-term survival compared to OR, without increasing the risk of serious infection-related complications or reoperations.