Effects of alirocumab on endothelial function and coronary atherosclerosis in myocardial infarction: A PACMAN-AMI randomized clinical trial substudy.

BACKGROUND AND AIMS: The effects of protein convertase subtilisin/kexin type 9 (PCSK9) inhibitors on endothelial function as assessed by flow-mediated dilation (FMD) in patients with acute myocardial infarction (AMI) are unknown. Therefore, we aimed to investigate the effects of the PCSK9 inhibitor alirocumab added to high-intensity statin on FMD, and its association with coronary atherosclerosis in non-infarct related arteries using intracoronary intravascular ultrasound (IVUS), near-infrared spectroscopy (NIRS), and optical coherence tomography (OCT). METHODS: This was a pre-specified substudy among patients recruited at Bern University Hospital, Switzerland, for the randomized-controlled, double-blind, PACMAN-AMI trial, which compared the effects of biweekly alirocumab 150 mg vs. placebo added to rosuvastatin. Brachial artery FMD was measured at 4 and 52 weeks, and intracoronary imaging at baseline and 52 weeks. RESULTS: 139/173 patients completed the substudy. There was no difference in FMD at 52 weeks in the alirocumab (n = 68, 5.44 ± 2.24%) versus placebo (n = 71, 5.45 ± 2.19%) group (difference = -0.21%, 95% CI -0.77 to 0.35, p = 0.47). FMD improved throughout 52 weeks in both groups similarly (p < 0.001). There was a significant association between 4 weeks FMD and baseline plaque burden (IVUS) (n = 139, slope = -1.00, p = 0.006), but not with lipid pool (NIRS) (n = 139, slope = -7.36, p = 0.32), or fibrous cap thickness (OCT) (n = 81, slope = -1.57, p = 0.62). CONCLUSIONS: Among patients with AMI, the addition of alirocumab did not result in further improvement of FMD as compared to 52 weeks secondary preventative medical therapy including high-intensity statin therapy. FMD was significantly associated with coronary plaque burden at baseline, but not with lipid pool or fibrous cap thickness.

Lesion-Level Effects of LDL-C-Lowering Therapy in Patients With Acute Myocardial Infarction: A Post Hoc Analysis of the PACMAN-AMI Trial.

Importance: Previous studies investigated atherosclerotic changes induced by lipid-lowering therapy in extensive coronary segments irrespective of baseline disease burden (a vessel-level approach). Objective: To investigate the effects of lipid-lowering therapy on coronary lesions with advanced atherosclerotic plaque features and presumably higher risk for future events. Design, Setting, and Participants: The PACMAN-AMI randomized clinical trial (enrollment: May 2017 to October 2020; final follow-up: October 2021) randomized patients with acute myocardial infarction to receive alirocumab or placebo in addition to high-intensity statin therapy. In this post hoc lesion-level analysis, nonculprit lesions were identified as segments with plaque burden 40% or greater defined by intravascular ultrasound (IVUS). IVUS, near-infrared spectroscopy, and optical coherence tomography images at baseline and the 52-week follow-up were manually matched by readers blinded to treatment allocation. Data for this study were analyzed from October 2022 to November 2023. Interventions: Alirocumab or placebo in addition to high-intensity statin therapy. Main Outcomes and Measures: Lesion-level imaging outcome measures, including high-risk plaque characteristics and phenotypes. Results: Of the 245 patients in whom lesions were found, 118 were in the alirocumab group (mean [SD] age, 58.2 [10.0] years; 101 [85.6%] male and 17 [14.4%] female) and 127 in the placebo group (mean [SD] age, 57.7 [8.8] years; 104 [81.9%] male and 23 [18.1%] female). Overall, 591 lesions were included: 287 lesions (118 patients, 214 vessels) in the alirocumab group and 304 lesions (127 patients, 239 vessels) in the placebo group. Lesion-level mean change in percent atheroma volume (PAV) was -4.86% with alirocumab vs -2.78% with placebo (difference, -2.02; 95% CI, -3.00 to -1.05; P < .001). At the minimum lumen area (MLA) site, mean change in PAV was -10.14% with alirocumab vs -6.70% with placebo (difference, -3.36; 95% CI, -4.98 to -1.75; P < .001). MLA increased by 0.15 mm2 with alirocumab and decreased by 0.07 mm2 with placebo (difference, 0.21; 95% CI, 0.01 to 0.41; P = .04). Among 122 lipid-rich lesions, 34 of 55 (61.8%) in the alirocumab arm and 27 of 67 (41.8%) in the placebo arm showed a less lipid-rich plaque phenotype at follow-up (P = .03). Among 63 lesions with thin-cap fibroatheroma at baseline, 8 of 26 (30.8%) in the alirocumab arm and 3 of 37 (8.1%) in the placebo arm showed a fibrous/fibrocalcific plaque phenotype at follow-up (P = .02). Conclusions and Relevance: At the lesion level, very intensive lipid-lowering therapy induced substantially greater PAV regression than described in previous vessel-level analyses. Compared with statin therapy alone, alirocumab treatment was associated with greater enlargement of the lesion MLA and more frequent transition of presumably high-risk plaque phenotypes into more stable, less lipid-rich plaque phenotypes. Trial Registration: ClinicalTrials.gov Identifier: NCT03067844.