Risk of ischemic stroke following amaurosis fugax versus transient ischemic attack

Amaurosis fugax is conventionally classified as a transient ischemic attack (TIA) subtype, yet the landmark trials guiding TIA management did not specifically enroll patients with amaurosis fugax. Clinicians frequently extrapolate TIA trial data to amaurosis fugax, potentially exposing patients to suboptimal diagnostic and treatment plans. We compared the risk of subsequent ischemic stroke after amaurosis fugax versus TIA.

Using the Nationwide Readmissions Database (2016-2022), we identified non-elective hospitalizations with a primary diagnosis of TIA or amaurosis fugax. Patients with amaurosis fugax were matched 1:2 to TIA patients using propensity-score matching on 25 covariates. Primary and secondary outcomes were any ischemic stroke and disabling ischemic stroke readmission, respectively, over 300 days. Additional 300-day outcomes were any non-elective readmission, major hemorrhage, intracranial hemorrhage, and death.

A total of 131,791 patients were identified, and after matching 4350 amaurosis fugax and 8,698 TIA patients remained. Patients with amaurosis fugax had significantly lower cumulative stroke probabilities (300-day: 1.5% vs 3.3%; HR 0.49 [95% CI 0.28-0.84], p = 0.01). Disabling stroke was similarly lower (HR 0.47 [95% CI 0.22-0.99], p = 0.048). Non-elective readmission was also lower (HR 0.84 [95% CI 0.73-0.98], p = 0.023), whereas major hemorrhage, intracranial hemorrhage, and death did not differ between groups.

Amaurosis fugax carries approximately half the subsequent stroke risk of TIA, without a corresponding excess of hemorrhage or death, suggesting these conditions have distinct natural histories, and patients with amaurosis fugax would likely benefit from distinct diagnostic evaluation and individualized risk-benefit assessments beyond simple application of TIA-derived diagnostic and treatment protocols.