ABSTRACT NUMBER: ESOC2026A1784 LONG-TERM OUTCOME OF PATIENTS WITH IATROGENIC CEREBRAL AMYLOID ANGIOPATHY

Abstract Background and aims Iatrogenic cerebral amyloid angiopathy (iCAA) has emerged as a rare but distinct CAA subtype, with increasing recognition worldwide. However, information on long-term prognosis remains limited. Methods After a systematic literature search for case series of iCAA (n≥5), we included patients from tertiary centres from four European countries (Austria, Italy, The Netherlands, United Kingdom). Patients meeting modified Queen Square criteria for iCAA were analysed. Outcomes included symptomatic intracerebral haemorrhage (ICH), convexity subarachnoid haemorrhage (cSAH), cognitive status at last follow-up, and mortality. Results We included 82 patients (59.8% male, median age at presentation 50 years, median latency to exposure 39 years). Most patients initially presented with intracranial haemorrhage (ICH: 50%, cSAH 32.9%). Over a median follow-up time of 3.8 years (IQR 1.8-5.9; total follow-up 385 patient-years), 74 symptomatic ICH occurred, corresponding to a rate of 19.2 per 100 patient-years after iCAA diagnosis. Patients who presented with ICH (compared to cSAH or other syndromes) had an increased rate of recurrent ICH (hazard ratio 3.14, 95% CI 1.55-6.33, p=0.001), while patients with spinal surgery as an exposure (n=24, compared to brain surgery or embolization) had a lower rate of ICH (hazard ratio 0.34, 95% CI 0.13-0.87, p=0.02). Six patients (7.3%) died during the follow-up period. Cognitive impairment at last evaluation was present in 36 patients (48.8%). Conclusions Following a long latency from presumed exposure, patients diagnosed with iCAA have a very high burden of symptomatic ICH, which appears to be influenced by both the type of clinical presentation and exposure event. Conflict of interest All authors: Nothing to disclose.