Abstract
INTRODUCTION: The 'strike early and strike strong' lipid-lowering strategy emphasises rapid reduction of low-density lipoprotein cholesterol (LDL-C) in patients with acute coronary syndrome (ACS). Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) are increasingly used alongside statins to achieve guideline-recommended LDL-C targets after ACS. However, despite substantial LDL-C reductions with early PCSK9i initiation, their effects on non-culprit coronary atherosclerotic plaques remain unclear. This study aims to assess the impact of early intensive LDL-C lowering with PCSK9i added to moderate-intensity statin therapy on optical coherence tomography (OCT)-derived plaque characteristics in non-culprit coronary lesions in patients with ACS. METHODS AND ANALYSIS: In this prospective, multicentre, open-label trial, 212 patients with ACS will be randomised 1:1 to an early intensified lipid-lowering strategy (PCSK9i added to moderate-intensity statin) or guideline-directed medical therapy for 6 months. Serial OCT imaging of non-culprit coronary arteries with 20-70% stenosis will be performed at baseline and 6 months. The primary endpoint is the absolute change in minimum fibrous cap thickness within a matched target arterial segment from baseline to 6 months. Secondary endpoints include changes in minimum lumen area, maximum lipid arc, presence of macrophage infiltration, LDL-C reduction and achievement of LDL-C targets. The primary endpoint will be analysed using analysis of covariance, adjusting for treatment group, baseline LDL-C stratification (≥1.8 vs <1.8 mmol/L), and baseline minimum FCT. Secondary continuous outcomes will be analysed similarly, while categorical outcomes will be compared using chi-square, Fisher's exact test or logistic regression, as appropriate. ETHICS AND DISSEMINATION: Ethics approval was granted by the Biomedical Research Ethics Committee of West China Hospital of Sichuan University (2024 Review No 1943). Results will be disseminated via peer-reviewed publications and presentations at academic conferences. TRIAL REGISTRATION NUMBER: NCT06791031.