Lipoprotein(a) plama levels during myocardial infarction

Abstract Background Elevated levels of lipoprotein(a) (Lp(a)) substantially affect the risk of cardiovascular events. New drugs targeting Lp(a) are likely to be considered for secondary prevention first. However, plasma concentrations of biomarkers and lipoproteins may change substantially in the aftermath of myocardial infarction and may fluctuate with inflammation and lipid-lowering treatment. Purpose Our aim was to assess the stability of plasma Lp(a) concentrations throughout the course of an ST-elevation myocardial infarction (STEMI) and to determine how Lp(a) levels changed with inflammation, anti-inflammatory treatment, and the initiation of lipid-lowering therapy. Methods We assessed plasma levels of Lp(a) in 199 treatment-naïve patients with STEMI who were randomized 1:1 to treatment with the interleukin-6 (IL6) receptor inhibitor tocilizumab or placebo within 6 hours of symptom onset. We measured Lp(a) at baseline, after 24 hours, after 3-7 days, after 3 months, and after 6 months. We measured the myocardial salvage index, infarct size, and microvascular obstruction by magnetic resonance imaging 3-7 days after the STEMI. We used mixed models to evaluated the change in Lp(a) across time and treatment allocation. Results The median plasma level of Lp(a) at baseline was 17 (IQR 6 – 86) nmol/L. Plasma levels rose slightly over the first days after STEMI to a peak value of 25 (IQR 9 – 118) nmol/L 3-7 days after STEMI. (Table 1). Despite large differences in CRP between the treatment arms, tocilizumab did not affect Lp(a) levels (Figue 1).. Six months after STEMI, the median Lp(a) concentration was 22 (IQR 8 – 110) nmol/L. Lp(a) was not associated with myocardial salvage, final infarct size, or the extent of microvascular obstruction. Conclusion After myocardial infarction, there was a statistically significant, but not clinically meaningful change in Lp(a) levels that was not affected by anti-inflammatory treatment. Levels measured in the aftermath of a myocardial infarction can be used to identify patients eligible for targeted therapy.Table 1 Lp(a) values after MI Lipoprotein(a) after MI