•Le, Buchanan, Wilkins, Yen, Tracci

Title: Chronic Contained AAA rupture with lumbar vertebra erosion

Body:

Chronic contained rupture of an abdominal aortic aneurysm is a rare complication, especially when associated with lumbar vertebrae erosion. Reported cases have generally been associated with primary aneurysms. We are reporting a case of a 67-year-old male who presented with several months of back pain following a recent endovascular aneurysm repair for infrarenal AAA. Computed tomography angiography (CTA) revealed enlarging aneurysm sac and a retroperitoneal mass with apparent erosion of L2 and L3 vertebral bodies and involving the left psoas muscle. Ferumoxytol magnetic resonance imaging revealed an endoleak unseen on CTA. The patient underwent EVAR explant and anatomic reconstruction with Rifampin-soaked Dacron. He was discharged 12 days after repair following a smooth postoperative course. Outpatient follow-up has confirmed stable and definitive repair.

Relevant history:

67-year-old male with a history of symptomatic bradycardia on pacemaker, hypertension, and hyperlipidemia, who presented at our emergency department with a complaint of back pain and abdominal pain for six months. Seven months prior, the patient had an elective endovascular aneurysm repair (EVAR) of a distal infrarenal abdominal aortic aneurysm measuring 4.9 cm. Shortly following his EVAR, the patient developed persistent abdominal and back pain with negative esophagogastroduodenoscopy and colonoscopy. Follow-up three-month CT revealed stable sac size and no endoleak. Despite this, he continued to have worsening symptoms associated with 60 lbs of weight loss over six months and intermittent subjective fever. The patient was eventually admitted to an outside hospital six months post-EVAR when a CT demonstrated no endoleak but the interval development of a heterogeneous lesion abutting the posterior AAA sac, involving the left psoas muscle as well as the L2 and L3 vertebral bodies, causing an L3 pathologic fracture. MRI showed a multiloculated lesion with multiple fluid-fluid levels measuring 7.9x6.1x10cm

Relevant test results:

This report presents a case of CCR AAA developed months after an EVAR due to an occult rupture. The actual leak was not seen on computed tomography angiography (CTA) or contrast magnetic resonance imaging (MRI). Instead, it was confirmed using a blood pool contrast MRI with ferumoxytol.

Teaching points:

This abstract focuses on the presentation, diagnostic workup, and surgical repair of a case of post-EVAR chronic contained ruptured AAA with lumbar erosion. Our patient is unique because his CCR AAA was likely due to an occult leak following EVAR, previously unreported. In our case, ferumoxytol MRI became exceptionally useful by visualizing the occult leak not seen on CTA or Gadolinium MRI. In patients with sac enlargement following EVAR without identifiable endoleaks, MRI with blood pool contrast agents has been reported to be beneficial. While most reports have described open repair for CCR AAA, there have been several cases of EVAR with favorable results. Current literature cannot support one approach over the other. However, such decisions must likely be individualized based on patient anatomy, baseline health, and surgeon preference/proficiency. In this case, we elected to pursue open repair due to the inability to rule out aortic infection, relating to the previously mentioned diagnostic dilemma.