Endovascular repair delivers good outcomes, aneurysmal sac resolution in mycotic aortic aneurysm

A Singapore study has shown the feasibility and durability of endovascular repair (EVAR) in mending patients with mycotic aortic aneurysm (MAA) who are on lifelong antibiotics, with a 5-year overall survival of 61 percent and a low recurrence rate of 9 percent for aneurysm-related sepsis.

“Although the aortic interventions performed were successful, immunocompromised patients had difficult postoperative recoveries,” the researchers noted. “All our patients saw a reduction in aneurysmal size at 1 month, with 65 percent having complete aneurysmal sac resolution by 12 months.”

Twenty-three consecutive patients with MAA (mean age, 62 years) who underwent EVAR from January 2008 to July 2017 were included in this retrospective study. The researchers based their diagnosis of MAA on a combination of the following criteria: clinical presentation (fever, pain, sepsis), biochemical results (leukocytosis, elevated inflammatory markers like C-reactive protein), and radiological findings (large aneurysms that were ruptured/contained, periaortic gas).

Broad-spectrum IV antibiotics were given to all patients 1–90 days before surgery in consultation with the infectious diseases physician. Those with positive blood cultures were switched to organism-specific antibiotics once the results were out, while the rest continued with broad-spectrum antibiotics.

Patients had a mean aneurysmal size of 3.2 cm. Sixteen patients (70 percent) had abdominal MAA and four (17 percent) had thoracic MAA. No death was recorded within 30 days in the cohort. Endoleak (types 1, 3, 4) was found in three (13 percent). [Singapore Med J 2020;doi:10.11622/smedj.2020165]

A reduction in aneurysmal size was observed in all patients and a complete aneurysmal sac reduction in five (22 percent) at the 1-month surveillance computed tomography aortogram. Furthermore, seven patients (30 percent) had sac resolution at 6 months and eight (35 percent) at 12 months. Overall survival was 91 percent at 1 month, 80 percent at 1 year, and 61 percent at 5 years.

“Our 5-year survival rate of 61 percent was similar to that of other studies, (18,19) while our in-hospital mortality rate was also comparable to that reported in other studies, (12,13,20,21) with a mean rate of 10 percent (range, 0–25 percent). [Ann Vasc Surg 2014;28:217-226; Circulation 2014;130:2136- 2142; Cardiovasc Intervent Radiol 2008;31:509-513; Vasc Endovascular Surg 2010;44:693-696]

In addition, no in-hospital mortality was reported with EVAR compared with open surgery (0 percent vs 12–17 percent), as shown in previous studies. [Eur J Vasc Endovasc Surg 2010;40:450-456; Eur J Vasc Endovasc Surg 2004;27:585-589; J Vasc Surg 2008;47:270-276]

“Thus, EVAR as the first-line treatment in patients with MAA is a reasonable approach due to its low in-hospital mortality rate,” the researchers said. “Notably, most of the identified studies did not report the 5-year survival rates due to the lack of follow-up.”

The current study was limited by its small sample size due to the rarity of the disease, its retrospective design, and the existence of patient selection bias. The median follow-up duration of 19 months was also not long enough to identify all cases of late aneurysm-related mortality.

“Therefore, an extended, multi-institutional study that compares the outcomes of open repair and EVAR would be recommended,” the researchers said.