Eung Koo Yeon1, Young Dae Cho2, Dong Hyun Yoo3, Su Hwan Lee4, Hyun-Seung Kang5, Won-Sang Cho5, Jeong Eun Kim5, Moon Hee Han6. 1. Department of Radiology, KyungHee University Medical Center, KyungHee University College of Medicine, Seoul, Korea (Republic of). 2. Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, 101 Daehak-ro, 110-744, Jongno-gu, Seoul, Korea (Republic of). aronnn@naver.com. 3. Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, 101 Daehak-ro, 110-744, Jongno-gu, Seoul, Korea (Republic of). 4. Department of Neurosurgery, Dongguk University Ilsan Hospital, Dongguk University College of Medicine, Goyang, Korea (Republic of). 5. Department of Neurosurgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea (Republic of). 6. Department of Radiology and Neurosurgery, Veterans Health Service Medical Center, Seoul, Korea (Republic of).
Abstract
PURPOSE: The aim was to monitor aneurysms that show imaging evidence of minor recanalization 36 months after coil embolization and to determine the rate and related risk factors of major recanalization during more prolonged observation. METHODS: A total of 54 patients with 55 aneurysms showing minor recanalization at 36-month follow-up imaging between 2011 and 2013 were retrospectively reviewed. Medical records and radiological data accumulating in the course of extended monitoring (mean 83.9 ± 21.5 months) were assessed. Incidence and average annual risk of progression to major recanalization were then calculated. Univariate and multivariate regression analyses were applied to determine possible risk factors for progression to major recanalization. RESULTS: In the 55 aneurysms studied 26 showed sustained minor recanalization since month 6 of follow-up, whereas minor recanalization of 29 completely occluded coiled lesions appeared in follow-up images after 6-24 months. Only 8 coiled aneurysms (14.5%) with minor recanalization at 36 months progressed to major recanalization during 219.3 aneurysm-years of observation (3.6% per aneurysm-year), 2 surfacing within 72 months and 6 developing thereafter. Additional embolization was performed in six of these patients. By multivariate analysis, no clinical or anatomic factors were statistically linked to such progression, but younger age showed marginal significance (hazard ratio, HR = 1.076; p = 0.099). CONCLUSION: Most coiled aneurysms (85.5%) showing minor recanalization at 36 months postembolization proved to be stable in extended observation. Given the low probability but seriousness of delayed major recanalization, careful monitoring is still warranted in this setting but at less frequent intervals (every 2-3 years) beyond 36 months.
PURPOSE: The aim was to monitor aneurysms that show imaging evidence of minor recanalization 36 months after coil embolization and to determine the rate and related risk factors of major recanalization during more prolonged observation. METHODS: A total of 54 patients with 55 aneurysms showing minor recanalization at 36-month follow-up imaging between 2011 and 2013 were retrospectively reviewed. Medical records and radiological data accumulating in the course of extended monitoring (mean 83.9 ± 21.5 months) were assessed. Incidence and average annual risk of progression to major recanalization were then calculated. Univariate and multivariate regression analyses were applied to determine possible risk factors for progression to major recanalization. RESULTS: In the 55 aneurysms studied 26 showed sustained minor recanalization since month 6 of follow-up, whereas minor recanalization of 29 completely occluded coiled lesions appeared in follow-up images after 6-24 months. Only 8 coiled aneurysms (14.5%) with minor recanalization at 36 months progressed to major recanalization during 219.3 aneurysm-years of observation (3.6% per aneurysm-year), 2 surfacing within 72 months and 6 developing thereafter. Additional embolization was performed in six of these patients. By multivariate analysis, no clinical or anatomic factors were statistically linked to such progression, but younger age showed marginal significance (hazard ratio, HR = 1.076; p = 0.099). CONCLUSION: Most coiled aneurysms (85.5%) showing minor recanalization at 36 months postembolization proved to be stable in extended observation. Given the low probability but seriousness of delayed major recanalization, careful monitoring is still warranted in this setting but at less frequent intervals (every 2-3 years) beyond 36 months.