De Novo Intracranial Aneurysms Detected on Imaging Follow-Up of Coiled Aneurysms in a Korean Population

Abstract

Objective Coiled aneurysms are known to recanalize over time, making follow-up evaluations mandatory. Although de novo intracranial aneurysms (DNIAs) are occasionally detected during routine patient monitoring, such events have not been thoroughly investigated to date. Herein, we generated estimates of DNIA development during long-term observation of coiled cerebral aneurysms, focusing on incidence and the risk factors involved. Materials and Methods In total, 773 patients undergoing coil embolization of intracranial aneurysms between 2008 and 2010 were reviewed retrospectively. Their medical records and radiologic data accrued over the extended period (mean, 52.7 ± 29.7 months) were analyzed. For the detection of DNIA, follow-up magnetic resonance angiography and/or conventional angiography were used. The incidence of DNIAs and related risk factors were analyzed using Cox proportional hazards regression and Kaplan-Meier product-limit estimator. Results In 19 (2.5%) of the 773 patients with coiled aneurysms, DNIAs (0.56% per patient-year) developed during continued long-term monitoring (3395.3 patient-years). Of these, 9 DNIAs (47.4%) were detected within 60 months, with 10 (52.6%) emerging thereafter. The most common site involved was the posterior communicating artery (n = 6), followed by the middle cerebral artery (n = 5) and the basilar top (n = 4). Multivariate analysis indicated that younger age (< 50 years) (hazard ratio [HR] = 1.045; p = 0.010) and recanalization of coiled aneurysms (HR = 2.560; p = 0.047) were significant factors in DNIA formation, whereas female sex, smoking, and hypertension fell short of statistical significance. Cumulative survival rates without DNIA were significantly higher in older subjects (> 60 years; p < 0.001) and in the absence of post-coiling aneurysm recurrence ( p = 0.006). Conclusion In most patients with coiled aneurysms, development of DNIAs during long-term monitoring is rare. However, younger patients (< 50 years) or patients with recurring aneurysms appear to be predisposed to DNIAs.

Mistakes to Avoid for Accurate and Transparent Reporting of Survival Analysis in Imaging Research

“…This approach [29,[33][34][35][36][37][38][39][40][41][42] may sound reasonable at a glance but is generally invalid. This analysis is logical only when the follow-up time is fixed and specified for the grouping of patients (e.g., patients developing events by 6 months after treatment vs. patients free of events until 6 months) and all patients have completely been followed until the specified time point (e.g., all have been followed until 6 months without dropouts unless they had events) [36][37][38]43].…”

Commentary: Formation, Growth, or Rupture of De Novo Intracranial Aneurysms: Long-Term Follow-up Study of Subarachnoid Hemorrhage Survivors

“…24 As UIA rupture risk is elevated in aSAH survivors, investigations into DNIA disease course are highly relevant in developing screening and management protocols in such patients. 21-26…”

“…[15][16][17][18][19][20] De novo aneurysm (DNIA) formation denotes novel nonrecurrent or residual lesions detected on follow-up in patients with a known history of intracranial aneurysm (IA), carrying an incidence of 1% to 5% per year. [21][22][23][24][25][26] DNIAs have been reported in a range of patients with pathology or those undergoing treatment that modulates intracranial hemodynamics, including malformation embolization/resection, endoluminal reconstruction/stenting, radiotherapy, and IA obliteration/ligation. [21][22][23][24][25][26] Clip ligation has been reported to carry a 20-yr cumulative risk of DNIA formation of 8% to 12%.…”

“…24 As UIA rupture risk is elevated in aSAH survivors, investigations into DNIA disease course are highly relevant in developing screening and management protocols in such patients. [21][22][23][24][25][26] The authors describe results from a comprehensive single-center retrospective analysis across 17 yr of DNIA incidence and rupture risk in 296 nonelderly, nonpediatric patients with a confirmed history of aSAH who underwent microsurgical clip ligation and had a documented decade of subsequent radiographic follow-up. 27 A total of 63 (21.2%) included patients with ultimate DNIA formation were compared with a control group of 233 without novel lesions detected after aSAH.…”

“…[21][22][23][24][25][26] DNIAs have been reported in a range of patients with pathology or those undergoing treatment that modulates intracranial hemodynamics, including malformation embolization/resection, endoluminal reconstruction/stenting, radiotherapy, and IA obliteration/ligation. [21][22][23][24][25][26] Clip ligation has been reported to carry a 20-yr cumulative risk of DNIA formation of 8% to 12%. 24 As UIA rupture risk is elevated in aSAH survivors, investigations into DNIA disease course are highly relevant in developing screening and management protocols in such patients.…”