Abstract TP185: Lipoprotein(a) Levels In Patients With Embolic Stroke Of Undetermined Source And Its Association With Non-stenotic Atherosclerotic Disease

Background: Lipoprotein(a) [Lp(a)]has been linked to increased atherosclerotic cardiovascular disease risk however there is limited data on Lp(a) in ischemic stroke subtypes. Current cholesterol management and ASCVD prevention guidelines include Lp(a) >50 mg/dL as a risk enhancer. Methods: This is a retrospective cohort of consecutive embolic stroke of undetermined source (ESUS) patients seen at the Emory Stroke Clinic and underwent Lp(a) testing in the outpatient setting from January 1, 2020 to March 31, 2022. Abnormal levels were defined as ≥ 30 mg/dl. Cerebrovascular imaging was reviewed by a board-certified neuroradiologist who was blinded to Lp(a) data. Results: Of 105 ESUS patients [median age 57 years (IQR 44-68), 51% female, 44% African American (AA)], median Lp(a) was 40 mg/dl (IQR 15-74) with 67 patients (64%) having Lp(a) ≥ 30 mg/dl, 45 (43%) ≥ 50 mg/dl and 30 (29%) having Lp(a) ≥ 70 mg/dl. Lp(a) levels were higher in AAs compared to other races (median 46 mg/dl vs 26 mg/dl , p= 0.002). Lp(a) level ≥ 30 mg/dl was associated with a higher serum D-dimer level median 536 (IQR 337-947, p=0.02), non-large vessel occlusion (LVO) stroke on initial imaging (p=0.012) and absence of MRI-FLAIR sequence abnormalities (p=0.044). In the subset of ESUS patients who underwent CT angiography of the head and neck (n=46), patients with Lp(a) level ≥ 50 mg/dl were more likely to have non-stenotic atherosclerotic plaque ipsilateral to the stroke territory (OR 6.1, 95% CI 1.3-28, p= 0.02). Conclusion: Lp(a) level ≥ 50 mg/dl was present in 43% of our cohort. This may be an under-recognized risk factor in ESUS. Further investigation is needed regarding the impact of Lp(a) on ESUS however our results suggest that ESUS patients with ≥ 50 mg/dl may benefit from a careful assessment of cerebrovascular imaging for ipsilateral non-stenotic atherosclerotic plaque in the territory of the stroke.