From the Guidelines
The treatment of mycotic aneurysms should involve a combination of antimicrobial therapy and surgical intervention, with in situ reconstruction being the preferred surgical approach due to its versatility, fewer long-term complications, and higher patency rates, as recommended by the 2022 ACC/AHA guideline for the diagnosis and management of aortic disease 1.
Overview of Treatment
The management of mycotic aneurysms is complex and requires a multidisciplinary approach. Antimicrobial therapy should be based on blood culture results and typically lasts for 6-8 weeks, with common regimens including vancomycin for gram-positive coverage and ceftriaxone or cefepime for gram-negative coverage, adjusted according to culture sensitivities 1.
Surgical Intervention
Surgical management is often necessary and includes resection of the infected aneurysm with debridement of surrounding infected tissue. The choice of surgical procedure depends on the location and size of the aneurysm, as well as the patient's stability.
- In situ reconstruction is the preferred approach due to its advantages, including fewer long-term complications, higher patency rates, and a lower recurrent infection rate, as outlined in the 2022 ACC/AHA guideline 1.
- Extra-anatomic reconstruction may be considered in cases where the aneurysm is located in the infrarenal region with gross purulence, psoas or retroperitoneal abscess, vertebral osteomyelitis, or inadequate response to antibiotic therapy.
- Endovascular device repair may be used as a bridge procedure for patients who are hemodynamically unstable, have uncontrolled bleeding, or are at high surgical risk, but it carries concerns about placing prosthetic material in an infected field and requires device explantation and reconstruction.
Considerations
The timing of surgery depends on the aneurysm's location, size, and the patient's stability, but intervention should not be delayed in cases of rupture, rapid expansion, or persistent infection. Long-term follow-up with imaging is essential to monitor for recurrence or development of new aneurysms, as these infections can be persistent and challenging to eradicate completely.
- The choice of antimicrobial therapy should be based on the identification and susceptibilities of the specific microorganism, and bactericidal therapy should be administered whenever possible 1.
- Empiric therapy is often necessary due to the potential for negative blood cultures and intraoperative tissue cultures in patients who have received prior antimicrobial therapy.
- A duration of 6 weeks to 6 months of antimicrobial therapy postoperatively may be considered, and in some cases, lifelong suppressive therapy may be necessary 1.
From the Research
Treatment Options for Mycotic Aneurysms
- Endovascular aneurysm repair (EVAR) is an emerging alternative to open repair (OR) for the treatment of mycotic aneurysms, particularly in high-risk surgical patients 2, 3, 4, 5.
- EVAR has been shown to be effective and safe in some cases, with technical success achieved in all patients and shrinkage of the aneurysm sac observed on CT-scan follow-up 2.
- However, EVAR may not be suitable for all patients, and open surgical repair (OSR) is still considered the first choice for hemodynamically stable and low-risk patients 6.
- In some cases, EVAR may be used as a temporary alternative for patients with ruptured aneurysms, hemodynamic instability, or high surgical risk, followed by timely secondary OSR 6.
Role of Antibiotic Therapy
- Standard antibiotic therapy is typically administered to patients with mycotic aneurysms, regardless of the surgical approach used 6.
- Suppressive antibiotic therapy may be used in conjunction with stenting to treat mycotic aneurysms, as seen in a case report of a patient with an Edwardsiella tarda infection 5.
Outcomes and Mortality Rates
- The overall mortality rate for mycotic aneurysms is significant, with a reported rate of 39.1% in one study 6.
- Mortality rates vary depending on the treatment approach, with open surgical repair associated with lower mortality rates compared to EVAR without secondary operation 6.
- Timely secondary OSR after initial EVAR may improve outcomes and reduce mortality rates 6.