European survey on follow-up strategies for unruptured intracranial aneurysms

Introduction: The increasing detection rates of unruptured intracranial aneurysms (UIA) pose a challenge for both neurovascular centers, tasked with managing a growing pool of patients requiring regular monitoring with imaging, and the healthcare system that must bear the costs of such surveillance. While there is consensus on the need for follow-up of UIA, uncertainties persist regarding the optimal cessation of surveillance, especially when considering diverse patient risk factors and, notably, in cases of treated aneurysms with stable rest perfusion. Detailed guidelines on UIA follow-up are currently lacking, exacerbating these challenges.

Research question: We sought to investigate European strategies for follow-up of untreated, microsurgically and endovascularly treated UIA.

Material and methods: An online survey consisting of 15 questions about follow-up management of UIA was sent out to the cerebrovascular section of the European Association of Neurosurgical Societies (EANS).

Results: The survey response rate was 27.3% (68/249). There was consenus upon the necessity for long-term follow-up of UIA (100% [n = 68]). The recommendation to perform follow-up was inversely correlated with patient age and more prevalent among endovascularly compared to microsurgically treated patients (92.6% [n = 63] vs. 70.6% [n = 48]). A majority recommended continued follow-up of treated aneurysms with stable rest perfusion, with lifelong surveillance in patients under 60 years and continuation for 5-10 years in patients aged 61-80, irrespective of whether they underwent microsurgical (38.3% [n = 23]; 33.3% [n = 20]) or endovascular (41.9% [n = 26]; 30.6% [n = 19]) treatment.

Discussion and conclusion: This survey confirmed a European consensus on the necessity of long-term follow-up for untreated UIA. However, significant variations in follow-up strategies, especially for treated UIA and post-treatment rest perfusion, were noted. Despite limited evidence suggesting low risk from aneurysm remnants, respondents favored long-term follow-up, highlighting uncertainty in management. This underscores the need for collaborative research on aneurysm remnants and standardized follow-up protocols for UIA in Europe.