Abstract WP068: Severe ADAMTS-13 Deficiency Without Hemolysis as an Underrecognized Cause of Recurrent Cryptogenic Stroke: A Single-Center Case Series

Introduction: Cerebral Infarction due to Severe ADAMTS-13 Deficiency (CISAD) remains an underrecognized cause of cryptogenic stroke. It can be a diagnostic challenge given the absence of microangiopathic hemolytic anemia, but requires prompt identification and treatment to improve mortality and prevent recurrent ischemic events. Methods: We conducted a retrospective cohort study at an urban hospital to identify all patients with ischemic stroke with severe ADAMTS-13 deficiency between January 2017 and June 2025. Of 235 initially screened patients, 9 met final inclusion criteria for CISAD: confirmed ischemic stroke, severe ADAMTS-13 deficiency at the index event, and absence of microangiopathic hemolytic anemia (MAHA). The final cohort was analyzed descriptively for clinical and hematologic characteristics. Results: Among the 9 patients, 7 were female and 2 were male, with a mean age of 51.3 years. Platelet counts were within normal limits in 6 of 9 cases. Of 9 patients with cryptogenic stroke and severe ADAMTS-13 deficiency without MAHA, 3 patients had never been diagnosed with TTP. One experienced three prior cryptogenic strokes before severe ADAMTS-13 deficiency was identified. The remaining 6 patients had a remote history of TTP and presented with stroke and severe ADAMTS-13 deficiency; 2 of the 6 patients each had multiple strokes with severe ADAMTS-13 deficiency. 8 of 9 patients met the criteria for Embolic Stroke of Undetermined Source (ESUS) before ADAMTS-13 levels resulted. All 9 patients were treated with a combination of steroids, therapeutic plasma exchange (TPE), and/or Rituximab. 4 patients suffered a subsequent episode of TTP with MAHA. 1 patient suffered a recurrent stroke. Conclusion: This case series highlights the fact that CISAD should be considered in patients with cryptogenic stroke even in the absence of hematologic abnormalities. Early recognition and ADAMTS-13 activity and inhibitor testing in select patients may allow timely diagnosis, treatment, and prevention of recurrence.