Abstract 2676: Lipoprotein associated-phospholipase A2 Activity Level is Increased in Acute Cerebral Ischemic Events

Abstract

Introduction: Lipoprotein associated -phospholipase A2 (Lpa-A2) mass and activity can help identify high risk TIA patients. We evaluate the yield of Lpa-A2 mass and activity to differentiate acute cerebral ischemic events from non-ischemic events. Methods: From July 2007 to March 2009, 48 patients presenting to the Stanford Unversity Medical Center Emergency room with stroke or TIA symptoms were prospectively enrolled and blood samples were obtained at time of presentation, 24 hours, and 72 hours after presentation. Blood samples were analyzed for Lpa-A2 mass and activity using commercially available assays (diaDexus, Inc). Patients with final diagnosis of stroke or TIA were classified as ischemic and others as non-ischemic. The size of the ischemic lesion was measured among stroke patients on diffusion weighted imaging (DWI). Results: Twenty eight patients (58%) had a diagnosis of brain infarction [median NIHSS=7 (IQR=4-12)], 9 (19%) had a diagnosis of TIA [median ABCD2=4, (IQR=3-6)] and 11(23%) had a non ischemic event (1 peripheral vertigo, 2 infections, 3 seizures, 4 peripheral neuropathy/myopathy, 1 multiple sclerosis relapse). Among the 37 ischemic patients, stroke mechanisms were according to TOAST criteria: 6 (16%) large artery atherosclerosis, 21 (57%) cardioembolic, 1 (3%) small artery, 4 (11%) other determined and 5 (13%) undetermined. At admission, Lpa-A2 activity level was higher among patients experiencing an ischemic event (stroke or TIA) compared to non ischemic event (p=0.007). Among ischemic patients, Lpa-A2 activity measured at admission was lower than the activity measured at day 1 (p=0.006) and day 3 (p=0.002) and was stable among non ischemic patients. Among the 24 ischemic patients who underwent acute MRI and were found to have an ischemic lesion on DWI, there was no relation between Lpa-A2 activity level and infarct volume. Lipoprotein associated -phospholipase A2 mass level was not different between ischemic and non ischemic patients. The mass levels remained stable over time in each group and were not related to infarct volume. Conclusions: Lpa-A2 activity levels were higher among ischemic patients compared with non ischemic etiologies. Lpa-A2 activity levels rose during the first days after brain ischemia. This exploratory data suggests Lpa-A2 activity level could possibly help physicians discriminate cerebral ischemic from non ischemic events. Further research is warranted and ongoing.