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Abstract 3452: Antiphosphatidylserine-prothrombin Antibodies Are Associated With Outcome After TIA


 Background and Purpose:
 Newly defined subclasses of antiphospholipid antibodies (aPLs) have been associated with thrombotic and atherosclerotic vascular events. We aimed to determine if they predict outcome after TIA.
 
 
 Methods:
 Detailed clinical data and blood samples were obtained prospectively from subjects with TIA hospitalized <48 hours from symptom onset. In a retrospective analysis standard aPLs, anti-cardiolipin (ACL) and β-2-glycoprotein-1 (β2GP1), and newer aPLs, anti-phosphatidylserine-prothrombin (aPS-PT), β2GP1 D4/5 subunit and β2GP1 D1 subunit, were measured by ELISA. The primary outcome was a composite endpoint of stroke or death within 90 days or identification of a high-risk stroke mechanism (defined as >50% stenosis in a vessel referable to symptoms or cardioembolism warranting anticoagulation). A secondary outcome was the presence of clinical or sub-clinical atherosclerosis.
 
 
 Results:
 Over 4.5 years, 167 patients were enrolled. Mean age was 62±14 years; 55% were female. Mean time from symptom onset to blood sampling was 26.2 ± 12.7 hours. Overall, 41 patients (25%) had the composite endpoint: 25 (15%) with a >50% stenosis, 14 (8%) with cardioembolism and 8 (5%) with clinical events (5 strokes, 3 deaths). The results of aPL testing using predefined cut-points to define positivity are summarized in the
 table
 . Using a cutoff of 30 units aPS-PT IgG antibodies were significantly associated with stroke/death (OR 17.3 95% CI 2.4-123.8 p=0.004) with a trend towards an association with the composite endpoint (OR 4.9 95% CI 0.8-30.4 p=0.09). In multivariate analysis adjusting for ABCD2 score, aPS-PT IgG remained associated with stroke/death (OR 16.6 95% CI 2.1-133.7 p=0.008). Using a data derived cut-off of 20 units (∼95% percentile within study population) aPS-PT IgG antibodies were significantly associated with stroke/death (OR 7.2 95% CI 1.2-42.5 p=0.03) and the composite endpoint (OR 4.2 95% CI 1.1-16.6 p=0.04). After adjusting for ABCD2 score, the association with stroke/death remained significant (OR 6.1 95% CI 1.0-38.5 p=0.05) and the composite endpoint approached significance (OR 3.8 95% CI 0.9-15.4 p=0.06). Elevated aPS-PT IgG levels occurred more frequently in subjects with clinical or sub-clinical atherosclerosis than those without (9% vs 0%, p=0.012). Other aPLs were not associated with atherosclerosis.
 
 
 Conclusion:
 In contrast to other aPLs, anti-phosphatidylserine-prothrombin IgG antibodies are elevated in high-risk TIA patients.
 
 
 
 
 
