Laser fenestration and shape memory polymer embolization of type II endoleaks

Abstract

Introduction: Treatment is recommended for type II endoleaks (T2ELs) with abdominal aortic aneurysm (AAA) sac expansion, but durable endovascular treatment remains challenging. Shape memory polymer (SMP) embolization plugs are a self-expanding, bioabsorbable polyurethane polymer designed to fill space rapidly within a vessel and provide a scaffold for rapid thrombosis. This case series describes a single institution's experience with transendograft laser fenestration and SMP embolization to treat difficult T2ELs. Methods: This is retrospective review of seven patients who underwent transendograft laser fenestration and SMP embolization. Laser fenestration was performed to target the endoleak. SMP plugs were then deployed into the aortic sac, and the endograft was realigned. The primary outcome was persistent aneurysmal sac growth at 1- and 6-month follow-up. Results: This study included five patients with prior infrarenal aneurysm repairs, one with a juxtarenal aneurysm repair, and one with a thoracoabdominal aneurysm repair. Five patients had previously undergone iliolumbar artery coiling, with a median of 1.0 prior interventions (interquartile range [IQR], 0.5-2.0) across the cohort. The median AAA diameter at the time of SMP embolization was 75.0 mm (IQR, 68.5-78.0 mm), with a median growth of 20.0 mm (IQR, 6.5-23.0 mm) from the index endovascular aortic repair. After embolization, three patients experienced continued AAA growth leading to additional reinterventions, including one patient who underwent endograft explant. Two patients showed growth at 6 months requiring reintervention. This resulted in an overall 6-month freedom from AAA growth of 42.9% in the entire cohort. Conclusions: The present series yielded a 6-month freedom from AAA growth in approximately 43% of patients. Refractory T2ELs represent a complex subset of patients with aneurysmal disease and, with future procedural refinements, SMP embolization holds promise as a minimally invasive therapy for this disease process.