Plaque characteristics in patients with very low low-density lipoprotein cholesterol levels not treated with statins: an intracoronary optical coherence tomography study

Abstract Background Statin therapy decreases serum low-density lipoprotein cholesterol (LDL-C), reduces coronary plaque volume, and stabilizes vulnerable plaques. LDL-C levels are recommended according to the patient's risk factors based on guidelines 1). In patients achieving low LDL-C levels such as LDL-C 70 mg/dL, the need for statins is uncertain, and the plaque characteristics of patients not treated with statins are unclear. Despite taking statins, patients with a high LDL-C level such as LDL-C ≥ 100 mg/dL have a high prevalence of familial hypercholesterolemia (FH) 2). Patients with FH are at a higher risk of coronary artery disease than those without FH regardless of LDL-C level 3); however, the plaque characteristics of patients with FH are not clear. Objective We evaluate the impact of statins for plaque characteristics on optical coherence tomography (OCT) in patients with very low LDL-C and high LDL-C levels. Methods A total of 200 patients with 213 lesions undergoing OCT before percutaneous coronary intervention were evaluated. We divided the LDL-C levels into three groups: 70 mg/dL (n = 53), 70 mg/dL ≤ LDL-C 100 mg/dL (n = 79), and ≥ 100mg/dL (n = 81). In each category, differences in plaque characteristics with and without statins were investigated. Results Among patients with LDL-C 70 mg/dL, patients not treated with statins showed a significantly higher C-reactive protein level (0.27 ± 0.22 mg/dL vs. 0.15 ± 0.19 mg/dL, p = 0.049), and thin-cap fibroatheromas (TCFAs; 47% 8/17 vs. 11% 4/36, p = 0.006) than those treated with statins. Among patients with LDL-C level ≥ 100 mg/dL, patients treated with statins showed a significantly higher prevalence of familial hypercholesterolemia (35% 7/20 vs. 5% 3/57, p = 0.001), lower incidence of lipid-rich plaques (30% 6/20 vs. 66% 40/61, p = 0.005), TCFAs (5% 1/20 vs. 39% 24/61, p = 0.004), healed plaques (25% 5/20 vs. 54% 33/61, p = 0.024), and higher incidence of fibrous plaques (60% 12/20 vs. 34% 21/61, p = 0.043) than patients not treated with statins. Among patients with an LDL-C level 70 mg/dL, the multivariable analysis showed that the absence of statins was one of the independent predictors of TCFAs (odds ratio 16.77, 95% CI 1.73 to 162.57, P = 0.015). Among patients with an LDL-C level ≥ 100 mg/dL, the multivariable analysis showed that the absence of statins was one of the independent predictors of TCFAs (odds ratio 8.65, 95% CI 1.04 to 72.20, P = 0.046). Conclusions While patients achieved a low LDL-C, patients not treated with statins had high plaque vulnerability and a high incidence of TCFAs, systemic inflammation, and CRP levels. While patients treated with statins in high LDL-C levels had a high prevalence of familial hypercholesterolemia, the patients had stable plaque characteristics, a low incidence of lipid-rich plaques, TCFAs, and healed plaques, and a high incidence of fibrous plaques.