Association between cholesterol crystals and 6-month prognosis in patients with acute coronary syndrome: an optical coherence tomography study

Abstract Background Optical coherence tomography (OCT) guided percutaneous coronary intervention (PCI) has been demonstrated to improve short and long-term outcomes compared with standard angiography-guided PCI. However, little is known about the impact of cholesterol crystals on the prognosis of patients with acute coronary syndrome (ACS) in the setting of receiving OCT-guided PCI. Purpose This study aims to investigate the association between cholesterol crystals and 6-month outcomes in ACS patients who underwent OCT-guided PCI. Methods Patients with ACS who underwent OCT-guided PCI in a high-volume PCI center between July 2020 and June 2022 were retrospectively enrolled and were further divided into two groups according to the presence or absence of cholesterol crystals. OCT imaging characteristics including plaque morphology before the PCI procedure in target lesions were assessed. The primary outcome was a composite of all-cause death, ischemia-driven revascularization, or readmission for heart failure in a 6-month follow-up period. The association between cholesterol crystals and 6-month outcomes was evaluated using Kaplan-Meier curves. Independent predictors for cholesterol crystals and 6-month outcomes were evaluated by the logistic regression and Cox proportional hazards regression analyses, respectively. Results 403 patients were enrolled in this study. The mean age was 61 years old and 79.4% were men. Cholesterol crystals were presented in 224 (55.6%) target lesions in patients with ACS. Baseline characteristics were not statistically different between the two groups in age, sex, smoke, previous hyperlipidemia, and other clinical features, except for diabetes, multivessel disease, and ACS classification (p <0.05). In the multivariable logistic regression analysis, cholesterol crystals were associated with diabetes, plaque rupture, lipid length, calcification, macrophage infiltration, and thin-capped fibroatheroma (all p <0.05). Patients with cholesterol crystals had higher risks of poor 6-month composite outcomes when compared to those without cholesterol crystals (13.4% vs. 6.7%, HR 2.09, 95%CI 1.07-4.09, p = 0.031), even after confounders adjustment for age, sex, diabetes, multivessel disease and ACS classification using inverse probability of treatment weighting (p = 0.027). Subgroup analysis showed significant interactions between cholesterol crystals and 6-month outcomes with respect to the male (HR 2.82, 95%CI 1.22-6.51, p = 0.015), target lesions in LAD (HR 4.47, 95%CI 1.29-15.44, p = 0.018), and incomplete revascularization (HR 3.08, 95%CI 1.04-8.98, p = 0.042). The Cox regression analysis identified cholesterol crystal as an independent predictor for 6-month composite outcomes (HR 2.12, 95%CI 1.08-4.19, p = 0.030). Conclusions The presence of cholesterol crystals was associated with a poor 6-month prognosis in patients with ACS, even in the setting of receiving OCT-guided PCI.