Management and outcomes in patients with cryptogenic stroke and weakly positive antiphospholipid antibodies.

BACKGROUND: The risk of recurrent stroke and optimal antithrombotic strategy for cryptogenic stroke in patients with weakly positive antiphospholipid antibodies (aPLs) are uncertain. OBJECTIVES: The aim of this study was to describe antithrombotic practice patterns and clinical outcomes, comparing patients with weakly positive aPLs with those with strongly positive aPLs. METHODS: This retrospective cohort study included patients who received care in the University of Pennsylvania Health System between March 1, 2017, and December 31, 2023, with index cryptogenic stroke or transient ischemic attack, positive aPLs persisting for ≥12 weeks, and not on antithrombotic therapy prior to the index event. We evaluated antithrombotic therapy recommendations using univariate hypothesis testing and clinical outcomes including stroke recurrence rate and major bleeding events using survival analyses, comparing patients with weakly positive aPLs and those with strongly positive aPLs. RESULTS: We identified 47 patients who met eligibility criteria, 30 weakly positive and 17 strongly positive. Warfarin was recommended less often (P = .007) and antiplatelet agents more often (P = .03) to patients with weakly positive aPLs, compared with those with strongly positive aPLs. With a median follow-up of 32 months (IQR, 24-48 months), the incidence of recurrent ischemic stroke was 0.169 events/person-year in the strongly positive group and 0.045 events/person-year in the weakly positive group (hazard ratio, 3.93; 95% confidence intervals, 1.14-13.55; P = .03). Bleeding events were rare. CONCLUSION: Most patients with cryptogenic stroke and weakly positive aPLs received antiplatelet agents. Patients with weakly positive aPLs had a lower incidence of recurrent stroke compared with patients with strongly positive aPLs, despite less intensive antithrombotic therapy.