Surgical Outcomes of Infective Native Aortoiliac Aneurysms in a Chilean Academic Center

Infective native aortic aneurysms (INAAs), formerly called mycotic aneurysms, remain an uncommon disease with significant heterogeneity among cases; hence, there is lack of solid evidence to opt for the best treatment strategy. The present study aims to describe a 20-year experience at a single institution treating this uncommon condition.

Retrospective study of all patients treated for INAA at a single academic hospital in Santiago, Chile, between 2002 and 2022. Clinical characteristics are described, as well as operative outcomes per type of treatment. Nonparametric Mann-Whitney U-test or Kruskal-Wallis tests were performed when appropriate, and results were reported as median and ranges. Survival at given timeframes was determined by a Kaplan-Meier curve, with analysis performed through a Cox regression model.

During the study period, 1,798 patients underwent aortic procedures at our center, of which 35 (1.9%) were treated for INAA. Of them, 25 (71.4%) were male. One patient had 2 INAAs. Median age was 69.5 years (range: 34-89 years). Of the 36 INAAs, the most frequent location was the abdominal and thoracic aorta in 20 (55.5%) and 11 (30.5%) cases, respectively, followed by the iliac arteries in 4 (11.1%) cases. One (2.7%) patient presented a thoracoabdominal INAA. Overall, endovascular treatment associated with long-term antibiotics was used in 20 (57.1%) patients: 4 of them underwent hybrid treatment. Fifteen (42.8%) patients underwent direct aortic debridement followed by in situ or extra anatomic revascularization. There was a significant difference in age between both treatment strategies (a median of 76.5 years for endovascular versus a median of 57 years for open, P = 0.011). The median hospital stay was 15 days (range: 2-70 days). The early complications rate (<30 postoperative days) was 20% (n = 7). Early mortality rate (inhospital or before postoperative 30 days) was 14.2% (n = 5). Median follow-up was 33 months (range: 6-216 months). The overall survival rates at 1, 3, and 5 years were 69.9% (standard error [SE] 8.0), 61.7% (SE 9.8), and 50.9% (SE 11.8), respectively. Five-year survival rate of patients undergoing endovascular treatment compared with open approach was 45.9% (SE 15.1) versus 80.0% (SE 17.8), respectively (P = 0.431). There were no significant differences in survival between open and endovascular treatment, hazard ratio 3.58 (confidence interval 95%: 0.185-1.968, SE ± 0.45 P = 0.454).

Patients treated by endovascular approach were older than patients treated by open approach. Even though, the open group had a higher 5-year survival rate than the endovascular group, not statically significance differences were found between treatments.