Association Between the Level of Low-Density Lipoprotein Cholesterol and Coronary Atherosclerosis in Patients Who Have Undergone Coronary Computed Tomography Angiography.

BACKGROUND: Although the Japan Atherosclerosis Society Guidelines 2017 recommend lower levels of low-density lipoprotein cholesterol (LDL-C, < 70 mg/dL or ≤ 100 mg/dL) to prevent secondary cardiovascular events, we cannot conclude that a low level of LDL-C prevents primary cardiovascular events in patients with suspected coronary artery disease (CAD). METHODS: We registered 1,016 patients who were clinically suspected to have CAD and who underwent coronary computed tomography angiography (CCTA) for screening of coronary atherosclerosis. We excluded 350 patients who were receiving anti-lipidemic therapies and finally analyzed 666 patients. The patients were divided into three groups according to the LDL-C level: < 70 mg/dL (n = 25, Low LDL-C), 70 - 99 mg/dL (n = 141, Middle LDL-C), and ≥ 100 mg/dL (n = 500, High LDL-C). A ≥ 50% coronary stenosis was initially diagnosed as CAD, and the number of significantly stenosed coronary vessels (VD), Gensini score and coronary artery calcification (CAC) score were quantified. RESULTS: There were no significant differences in age, high-density lipoprotein cholesterol, rates of hypertension, hemoglobin A1c, blood sugar or systolic blood pressure among the Low, Middle and High LDL-C groups. On the other hand, there were significant differences in rates of males, smoking, dyslipidemia and diabetes, diastolic blood pressure and triglyceride among the groups. The prevalence of CAD values in the Low, Middle and High LDL-C groups were similar, at 52%, 47%, and 46%, respectively. In addition, there were no significant differences in the number of VD, Gensini score or CAC score among the Low LDL-C, Middle LDL-C and High LDL-C groups. CONCLUSIONS: We showed that the level of LDL-C was not associated with the presence or severity of CAD, which indicates that we need to screen by CCTA to prevent primary coronary events even if patients without anti-lipidemic therapies show low levels of LDL-C.

Ezetimibe Monotherapy Reduces Serum Levels of Platelet-Activating Factor Acetylhydrolase in Patients With Dyslipidemia.

BACKGROUND: The combination of ezetimibe with statin therapy reduced cardiovascular events compared to statin monotherapy in IMPROVEIT study, and ezetimibe monotherapy attenuated atherosclerosis in basic study. We previously showed ezetimibe monotherapy was especially effective for metabolic syndrome (MetS) patients. We investigated the effects of ezetimibe monotherapy for high-density lipoprotein cholesterol (HDL-chol) function and platelet-activating factor acetylhydrolase (PAF-AH) activity. METHODS: Forty-two patients who initially received ezetimibe (10 mg/day) without statin treatment for 16 weeks from January 2009 to August 2011 were enrolled. Patients were divided into MetS and non-MetS groups, and serum levels of lipids, PAF-AH, and HDL-chol efflux capacity (HDL-CEC) at baseline and after 16 weeks of treatment were investigated. Serum PAF-AH, HDL-associated PAF-AH (HDL-PAF-AH), and LDL-associated PAF-AH (LDL-PAF-AH) were measured. RESULTS: In all patients, age, the percentages of males, and body mass index were 61.0 ± 8.8 years, 59.5% and 26.3 ± 3.4 kg/m2, respectively. Total cholesterol and low-density lipoprotein cholesterol (LDL-chol) were significantly decreased by ezetimibe monotherapy. Serum PAF-AH and LDL-PAF-AH were significantly decreased by ezetimibe monotherapy, whereas HDL-PAF-AH and HDL-CEC were not. There was no difference in the results of PAF-AH and HDL-CEC between MetS and non-MetS groups. CONCLUSIONS: Ezetimibe monotherapy might prevent coronary heart disease (CHD) regardless of the presence of MetS, because PAF-AH was independent risk factor for CHD.