(212) Pediatric Aortic Aneurysms: Navigating Diagnostic Challenges

Introduction: Only 31 cases of congenital abdominal aortic aneurysms (CAAA) have ever been reported. They are rare but can be fatal (mortality rate 31%). We report the case of an infant diagnosed with a 5 by 7cm CAAA with associated arterial-venous fistula (AVF).

Description: Previously healthy term 7-month-old girl appeared pale and floppy while feeding, concerning for syncope. In the ED, she was tachycardic (210 bpm), normotensive (90/40 mmHg), hypoxic (83%), tachypneic (40’s), and afebrile. She had mild abdominal tenderness and a swollen purple left leg. Labs were normal except for a lactate of 2.8. PICU fellow performed a bedside abdominal ultrasound, finding an unexpected fluid filled mass prompting a CT/CTA which revealed, an infrarenal CAAA measuring 5x4.5x7.5 cm with an intramural clot (2.5 cm) and a left common iliac vein fistula connected to the aneurysmal sac. ECHO showed no right heart strain. She urgently went to the OR for a 5 hour open abdominal repair. Adult vascular, endovascular, pediatric cardiothoracic, and general surgical teams were all involved in the repair. Intraoperatively, the CAAA was repaired with a bifurcated 8mm polytetrafluoroethylene graft in end-to-end configuration between aorta and right common iliac artery and a side to end graft to the left common iliac artery, followed by primary repair of the aorto-left common iliac vein fistula. She recovered in the PICU for 6 days and was discharged on hospital day 9 Genetic testing was negative.

Discussion: Pediatric AAAs are often associated with connective tissue disorders, vasculitis, umbilical line complication, and infections. Ilio-iliac AVFs (II-AVFs) account for only 1% of CAAAs. Patients with II-AVFs typically present with high-output heart failure, abdominal pain, abdominal bruits/thrills, pulsatile abdominal mass, and venous congestion. Rupture of aortoiliac aneurysms into the iliac vein or vena cava is uncommon but can be fatal by rapid hemorrhagic shock, exsanguination, and death. Preoperative recognition of AVF associated with CAAA informs surgical planning. Peri-operative mortality is higher when AVF is not diagnosed. Early recognition of CAAA and AVF is crucial given that surgical repair strategies are highly individualized, impacted by the size, location, age of aneurysm, and require multiple surgical teams.