Endovascular Therapy of 500 Small Asymptomatic Unruptured Intracranial Aneurysms

Abstract

BACKGROUND AND PURPOSE:Although the natural course of UIAs remains unclear, the risk of aneurysmal SAH due to small (Ͻ10 mm) asymptomatic UIAs is low. Endovascular therapy for UIAs has increased because of device development and the need for less invasive treatment. We report the results, safety, and efficacy of endovascular therapy of small asymptomatic UIAs.

Current Trends and Results of Endovascular Treatment of Unruptured Intracranial Aneurysms at a Single Institution in the Flow-Diverter Era

“…Of these, 2690 aneurysms (57.7%) were completely occluded and 1490 (31.9%) had small residual necks. The rate of incomplete occlusion following coiling ranged from 1.2% to 20.8% in larger studies, [17][18][19][20][21][22][23] similar to our finding of 8% in the coiling group. The rate of complete occlusion in the FD group with at least 6 months of follow-up of 64.4% is lower than that in other flow-diverter studies; however, the low rate of retreatment (6%) is in line with those previously reported.…”

Endovascular Therapy for Asymptomatic Unruptured Intracranial Aneurysms

“…Although Im et al 9 and Oishi et al 10 have recently reported comparatively large-volume series, most …”

“…However, the patients were a mean of 10 years, and most aneurysms (87.3%) were <10 mm. Although the Japanese guidelines recommend treating UIAs ≥5 mm in maximal diameter, 15 UIAs <5 mm account for 35.4% of the total; Oishi et al 10 reported that 223 (44.6%) of 500 small (<10 mm in diameter) treated UIAs were <5 mm. As part of the annual health checks characteristic of the unique Japanese healthcare system, complete physical examinations and whole brain screenings are widespread, and more small UIAs have been discovered through these routine procedures than elsewhere.…”

“…We defined morbidity and mortality as any deterioration >0 on the mRS and any death related to treatment, respectively, which were similar to Oishi's definitions. 10 We determined 2.1% and 0.3% morbidity and mortality rates from JR-NET and JR-NET2 data, respectively, which we think are justified. We could not evaluate cognitive status as in the ISUIA study, and because neurologists did not always perform independent neurological examinations, we might have underestimated morbidity.…”

“…Table 1 shows the 16 locations of cerebral aneurysms listed in the registration studies. The aneurysms were classified according to maximal diameters of 3,5,10, and 20 mm. Aneurysms <10 mm were also classified as having favorable (neck, ≤4 mm; dome-to-neck ratio, ≥1.5) or wide (neck, >4 mm or dome-to-neck ratio, <1.5) necks.…”