Observational study: Temporal dynamics of lipoprotein(a) after out-of-hospital cardiac arrest: The Biobank Working Group.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) is a major cause of death in the USA and Europe, with survival rates around 10%. Lipoprotein(a) [Lp(a)] is an established cardiovascular risk factor, but its temporal profile following OHCA is unknown. METHODS: In this retrospective study at a tertiary cardiac arrest center, 50 adult patients with OHCA of presumed cardiac origin were included and stratified by 6-month neurological outcome (CPC 1-2 vs. CPC 3-5). Longitudinal Lp(a) concentrations were analyzed using a linear mixed-effects model with fixed effects for time point, neurological outcome, and their interaction. Exploratory logistic regression assessed associations between Lp(a) at ROSC and neurological outcome. RESULTS: 26 patients had a favorable outcome, and 22 had an unfavorable outcome (two patients were excluded after analysis due to problems with the sample). Baseline characteristics were similar, except for longer low-flow duration (p = 0.005), higher cummulative epinephrine dosage (p = 0.025) and lower pH (p = 0.013) in the unfavorable group. Absolute Lp(a) concentrations at ROSC did not differ between groups (p = 0.646) and were not associated with outcome. In the mixed-effects model, both timepoint (p < 0.0001) and the timepoint × outcome interaction (p = 0.020) were significantly associated with Lp(a) concentrations. Lp(a) remained relatively stable in patients with a favorable outcome, whereas it declined significantly over 48 h in those with an unfavorable outcome. CONCLUSION: Lp(a) exhibits a time-dependent trajectory after OHCA that differs by neurological outcome. While baseline levels are not predictive, patients with unfavorable outcomes show a significant decline over time, suggesting a dynamic response possibly linked to disease severity.