Impact of alirocumab on neoatherosclerosis formation and vessel healing after drug-eluting stent implantation in patients with acute myocardial infarction: a substudy of the PACMAN-AMI trial

Higher on-treatment levels of low-density lipoprotein cholesterol in statin-treated patients were reportedly associated with the occurrence of neoatherosclerosis after drug-eluting stent (DES) implantation. We aimed to investigate the impact of alirocumab added to high-intensity statin therapy on neoatherosclerosis formation among patients with acute myocardial infarction (AMI) treated with DES. This was a pre-specified substudy of the PACMAN-AMI trial, a randomized, double-blind trial comparing alirocumab versus placebo added to high-intensity statin therapy in AMI patients. The present study included patients undergoing optical coherence tomography assessment of DES in the culprit lesion at one year. The frequency of neoatherosclerosis, neointimal thickness, and strut malapposition were compared between treatment groups. Among 191 patients (95 with alirocumab and 96 with placebo), neoatherosclerosis was observed in 13 patients (6.8%) at one year. There was no significant difference in the frequency of neoatherosclerosis between treatment groups (alirocumab 4.2% vs. placebo 9.4%, P = 0.25). Among 11 patients with lipid-laden neointima, minimal fibrous cap thickness was greater in the alirocumab group than in the placebo group (217.5 ± 122.5 vs. 87.8 ± 49.1 μm, P = 0.02). Neointimal thickness (136.2 ± 71.1 vs. 151.4 ± 101.4 μm, P = 0.45) and the frequency of malapposed struts (0.94 vs. 0.53%, P = 0.27) were comparable between treatment groups. Among AMI patients treated with DES, there was no significant impact of alirocumab on the frequency of neoatherosclerosis and vessel healing at one year. The observed numerical difference and the finding of more stable neoatheroma in the alirocumab group need further investigation in larger studies with extended follow-up.