An Anatomic Classification Scheme for Surgical Planning of Renal Artery Aneurysms

Purpose: Renal artery aneurysm (RAA) is a rare disease. This study proposed and evaluated a new classification for RAA to assist in surgical decision-making. Materials and Methods: Single-center data of 105 patients with RAAs from the vascular department of vascular surgery were collected retrospectively. A new classification scheme was proposed. Type I aneurysms arise from the main trunk, accessory branch, or first-order branches away from any bifurcation. Type II aneurysms arise from the first bifurcation with narrow necks (defined as dome-to-neck ratio >2) or from intralobular branches. Type III aneurysms with a wide neck arise from the first bifurcation and affect 2 or more branches that cannot be sacrificed without significant infarction of the kidney. Results: There was 50 (47.62%) type I, 33 (31.43%) type II, and 22 (20.95%) type III aneurysms. The classification assigned endovascular repair as first-line treatment (for type I or II), while open techniques were conducted if anatomically suitable (for type III). A kappa level of 0.752 was achieved by the classification compared with a level of 0.579 from the classic Rundback classification. Technical primary success was achieved in 100% and 96.05%, and symptoms were completely resolved in 100% and 84.85%, while hypertension was relieved in 84.21% and 72.92% of patients receiving open surgery or endovascular repair, respectively. No significant difference was observed for perioperative or long-term complications among the 3 classification types. Conclusion: The new classification proved to be a convenient and effective method for facilitating choice of intervention for RAAs. Clinical Impact This study proposed and evaluated a new classification scheme for renal artery aneurysms, which proved to be a convenient and effective method for facilitating surgical decision-making. Coil embolization was the first-line treatment if suitable, while aneurysm resection and reconstruction with vein graft were conducted for some complex lesions. The safety and efficacy of both open and endovascular methods were validated.