Abstract Body: Introduction:
Cerebral amyloid angiopathy (CAA) can present with transient focal neurological episodes and is itself associated with a heightened risk of intracerebral hemorrhage (ICH). Therefore, in patients with suspected transient ischemic attack (TIA), CAA can impact diagnostic evaluation and antithrombotic management. However, among patients presenting with possible TIA, there are few data on the prevalence of CAA and its associated risk of future cerebrovascular events and mortality.

Methods:
We retrospectively analyzed consecutive patients presenting to Bern University Hospital, Switzerland between 2015 and 2019 with reversible neurological deficits lasting <24 hours and no evidence of acute ischemia on brain MRI. Two neurologists reviewed these patients’ MRI scans to evaluate for CAA according to the Boston Criteria, v2.0. Long-term outcomes included mortality, which was determined through the Swiss Population Registry, and subsequent cerebrovascular events (ICH, ischemic stroke, and TIA), which were assessed via electronic health record review. Cox regression models were used to evaluate the association between possible or probable CAA and outcomes after adjustment for age, sex, ABCD2 score, and antithrombotic use at discharge.

Results:
Of 1,117 subjects presenting during the study period with transient neurological symptoms and no acute ischemia on MRI, 21 (2%) met radiographic criteria for possible CAA and 30 (3%) met criteria for probable CAA. During a median follow up of 4.8 (interquartile range, 3.3-6.3) years, 7 patients (1%) had an ICH, 62 patients (5%) had an ischemic stroke , 72 patients (6%) had a TIA, and 181 patients (16%) died. In multivariable Cox regression analysis, there was no association between possible or probable CAA and the risk of future cerebrovascular events (adjusted hazard ratio [aHR], 0.94; 95% CI, 0.37-2.35) or mortality (aHR, 1.30; 95% CI, 0.83-2.01).

Conclusions:
In a cohort of patients presenting with possible TIA, the prevalence of radiographic criteria for possible or probable CAA was 5%. We did not find an association between possible or probable CAA and the risk of future ICH, ischemic stroke, TIA, or mortality. Further studies are needed to inform optimal diagnostic evaluation and management of patients meeting CAA diagnostic criteria presenting with transient neurological deficits.