Subsequent Thrombotic Outcomes in Patients with Ischemic Stroke with Antiphospholipid Antibody Positivity

International consensus criteria for antiphospholipid syndrome (APS) require persistently positive antiphospholipid antibodies (aPL) and medium or high titers in association with clinical manifestations. However, the clinical relevance of persistence and titers of aPL in patients with stroke has not been identified. We aimed to investigate the risk of subsequent thrombotic events in patients with ischemic stroke with aPL positivity in terms of aPL status.

We reviewed the medical records of 99 patients with ischemic stroke with at least one or more aPL-positivity (i.e., positivity for aCL, anti-β2-glycoprotein-1, and/or lupus anticoagulants). The patients were divided into two groups: "definite APS" who fulfilled the laboratory criteria and "indefinite APS" who fell short of the criteria. We compared the risk of subsequent thrombotic events between the two groups. Cox proportional hazards model and Kaplan-Meier survival curves were used for the analyses.

Of the 99 patients, 46 (46%) were classified as having definite APS and 53 (54%) as having indefinite APS. The mean follow-up was 51.6 months. Overall event numbers were 14 (30.4%) in definite APS and 16 (30.2%) in indefinite APS. Increased subsequent thrombotic events (hazard ratio 1.039; 95% confidence interval 0.449-2.404; p=0.930) and decreased time to thrombotic events (log-rank p=0.321) were not associated with aPL status.

There was no increased risk of subsequent thrombotic events in ischemic stroke patients with definite APS, compared with those with indefinite APS.