Variability of lipoprotein(a) levels in patients with acute myocardial infarction between admission, discharge, and follow-up

Aims Lipoprotein(a) [Lp(a)] is an established risk factor for atherosclerotic cardiovascular disease. Using Lp(a) concentrations measured during stable follow-up as the reference, we aimed to assess the temporal variability of Lp(a) after acute myocardial infarction (AMI) and to explore a pragmatic strategy for Lp(a) measurement. Methods and results The FRENCHIE-Lp(a) cohort enrolled consecutive adults hospitalized for AMI in 21 centres. Lp(a) mass concentration, measured at admission, hospital discharge, and 3–12 months follow-up, was analysed both as a continuous and predefined categorical variable (≤20, >20–≤50, >50–≤70, >70 mg/dL). Assuming follow-up Lp(a) as the reference, we aimed to identify the threshold values that would allow us to accurately identify patients with Lp(a) > 70mg/dL, the threshold mostly used for patient selection in phase III trials of targeted Lp(a) therapies. A cumulative threshold analysis was performed to identify the Lp(a) value below which the misclassification rate (i.e. % of patients with follow-up Lp(a) > 70 mg/dL) remained <1%. Among 1561 patients (aged 61 ± 12 years; 21.3% women), median Lp(a) was 13 mg/dL at admission and remained stable over time (median difference overtime = 0 mg/dL). However, only 68.5% of patients remained in the same Lp(a) category overtime. In patients with discharge-Lp(a) ≤37 mg/dL (72.5% of the population), only 0.97% had Lp(a) >70 mg/dL at follow-up compared to 39.9% of those with discharge-Lp(a) >37 mg/dL. Conclusion Although the median Lp(a) level remained stable between admission and follow-up, one-third of AMI patients shifted within Lp(a) categories over time. Pending external validation, an exploratory two-step strategy based on Lp(a) measurement at discharge, followed by repeat testing in patients with Lp(a) >37 mg/dL, showed a misclassification rate below 1% for identifying patients potentially needing intervention. Registration Clinical trial Number: NCT04050956