Abstract Body: Background and Purpose: Antiphospholipid antibody syndrome (APS) is a rare cause of cerebral infarction, but the effect of antiphospholipid antibodies (aPL) on the acute phase of ischemic stroke in each stroke subtypes is still unclear, especially in the elderly patients. To clarify this, we compared antiphospholipid antibody levels in patients with acute cerebral infarction with or without recurrence, expansion, or hemorrhagic transformation of infarct in each stroke subtype.
Methods: Consecutive ischemic stroke patients in a comprehensive stroke center were screened between April 2013 and April 2024. Inclusion criteria were: 1) admitted 24 hours from the onset, 2) more than 60 years-old on the admission, 3) who had follow-up MRI/CT around one week from the onset, and 4) whose aPL (anti-cardiolipin-beta2-glycoprotein I complex antibody [β2-GPI], anti-cardiolipin antibody [aCL] and lupus anticoagulant [LAC]) measured during the admission for suspected APS. Then, we dichotomized the patients with and without recurrence (R), expansion (E), or hemorrhagic transformation (HT) of infarct upon follow-up MRI/CT findings. We compared clinical features including aPL between the groups by each stroke subtypes based on TOAST classification. Sensitivity and specificity were calculated from receiver operating characteristic (ROC) curve of aPL for predicting R, E, and HT.
Results: We screened 2,528 consecutive ischemic stroke patients and 271 patients met the inclusion criteria (60 [22%] cardioembolism (CE), 43 [16%] large-artery atherosclerosis, 29 [11%] small-vessel occlusion and 139 [51%] others). In enrolled patients, 30 (11%) patients showed R, 43 (16%) patients for E and 65 (24%) patients for HT. In CE, CL aCL and LAC were higher in patients with R compared without R (aCL 9.5 vs. 8.0 U/mL, p=0.047; LAC 1.15 vs. 1.01, p=0.006) while aPL were not significantly different in other stroke subtypes. Also, aPL were not significantly different between the patients with and without E or HT. In CE, R increased as LAC became higher (1st tertile vs. 2nd tertile vs. 3rd tertile of LAC: 0 (0%) vs. 1 (6%) vs. 6 (33%), p=0.004). In ROC analysis, the optimal cutoff of LAC for predicting R in CE was 1.12 (area under curve 0.83 [95% confidence interval 0.71-0.94], p=0.006; sensitivity 0.86, specificity 0.82).
Conclusions: In CE, LAC was associated with acute recurrence of infarct. LAC should be measured in cardioembolic stroke with recurrence in acute phase.