Endovascular therapy for asymptomatic unruptured intracranial aneurysms: JR-NET and JR-NET2 findings

Abstract

Background and purpose: National registration studies (the Japanese Registry of Neuroendovascular Therapy [JR-NET] and JR-NET2) have determined the current status and outcomes of neuroendovascular therapy (neuro-EVT). We analyzed short-term outcomes of EVT for asymptomatic unruptured intracranial aneurysms (UIAs).

Methods: We extracted periprocedural information about EVT for 4767 asymptomatic UIAs from 31,968 registered procedural records of all EVT in the JR-NET and JR-NET2 databases. We assessed the features of the aneurysms and procedures, immediate radiographic findings, procedure-related complications, and clinical outcomes at 30 days after the procedures.

Results: We located 80.0% of UIAs in the anterior circulation, and the most frequent were paraclinoid. The diameter of 2.5%, 32.9%, 51.9%, 12.0%, and 0.7% of the UIAs was <3, 3 to 4, 5 to 9, 10 to 19, and >20 mm, respectively. EVT failed in only 2.1%. Adjunctive techniques were applied in 54.8% of procedures. Pre- and postprocedural antiplatelet agents were prescribed in 85.6% and 84.0%, respectively, of the procedures. The immediate radiographic outcomes of 57.7%, 31.9%, and 10.0% of the UIAs comprised complete occlusion, residual necks, and residual aneurysms, respectively. Complications that were associated with 9.1% of procedures comprised 2.0% hemorrhagic and 4.6% ischemic, and the 30-day morbidity and mortality rates were 2.12% and 0.31%, respectively.

Conclusions: The radiographic results of EVT for asymptomatic UIAs in Japan were acceptable, with low mortality and morbidity rates.

Keywords: complications; embolization; endovascular procedures; intracranial aneurysm; treatment outcome; unruptured aneurysm.