Abstract Body: Introduction: Embolic stroke of undetermined source (ESUS) comprises heterogeneous causes and is associated with a 5-7% annual recurrence rate. While Lipoprotein (a) [Lp(a)] is an established risk factor for ischemic stroke, there is limited data on its contribution to ESUS patients. The objective of this study was to ascertain the frequency of Lp(a) elevation in a diverse ESUS cohort.

Method: Consecutive ESUS patients were prospectively identified and enrolled in The Emory Clinic ESUS Registry. All patients underwent biomarker testing including Lp(a) measurement. Abnormal Lp(a) was defined as ≥ 50mg/dl. We compared levels across race and gender.

Results: Of 340 ESUS patients, 186 (54%) were female, 156 (46%) black and 151 (44%) white with median age 60 (IQR 47-71) years. Median Lp(a) was 35 (IQR 12-81). Overall, 135 (40%) had Lp(a) ≥ 50 mg/dl, 106 (31%) Lp(a) ≥ 70 mg/dl and 68 (20%) with Lp(a) level ≥ 100 mg/dl (Figure). Blacks had significantly higher Lp(a) levels than whites and other races (p<0.001); 86 (55%) had Lp(a) ≥ 50 mg/dl. There was no significant difference in Lp(a) levels by gender.

Conclusion: Elevated Lp(a) levels were seen in 40% of ESUS patients, including a majority of black American ESUS patients. Given that Lp(a) is a risk factor for ischemic stroke, independent of LDL cholesterol, ESUS patients should be assessed for Lp(a) as part of routine evaluations. Ongoing clinical trials assessing novel treatments to lower Lp(a) will clarify the optimal medical management of patients with elevated Lp(a).