Usefulness of Preoperative Renal Scintigraphy for Treatment Planning before Endovascular Repair of an Abdominal Aortic Aneurysm with a Horseshoe Kidney: A Case Report.

INTRODUCTION: The optimal treatment strategy for abdominal aortic aneurysms associated with a horseshoe kidney remains controversial because of the complex renal vascular anatomy and the potential risk of renal function deterioration following accessory renal artery (ARA) occlusion. We report an exploratory case in which preoperative renal scintigraphy was used as an adjunctive functional assessment to assist treatment planning before endovascular aortic repair (EVAR). CASE PRESENTATION: A 47-year-old man was incidentally diagnosed with a 65-mm left common iliac artery aneurysm associated with a horseshoe kidney supplied by 8 ARAs. Preoperative dynamic renal scintigraphy demonstrated that the renal isthmus accounted for 24.5% of the total renal function. Because EVAR required the occlusion of 5 ARAs supplying the right kidney and renal isthmus, preoperative functional assessment suggested that sufficient renal function would likely be preserved despite partial ischemia of the isthmus, supporting the decision to perform EVAR. Postoperative renal scintigraphy demonstrated reduced perfusion of the isthmus but preserved overall renal function. Although the postoperative functional findings differed from the preoperative estimation, renal function remained clinically acceptable, and contrast-enhanced CT showed no evidence of an endoleak. CONCLUSIONS: This case suggests that preoperative renal scintigraphy may provide additional functional information beyond anatomical imaging and may assist treatment planning for selected patients with abdominal aortic aneurysms and horseshoe kidneys undergoing EVAR. However, the discrepancy between the preoperative functional estimation and the postoperative findings highlights the exploratory nature of this report, and further studies are required to clarify the clinical utility of this approach.