Background and aims: Dyslipidemia with elevated triglycerides (TGL) and low high-density lipoprotein cholesterol (HDL-C) predicts residual cardiovascular risk, despite goal LDL-C levels and optimal statin therapy. Coronary plaque characterization by CCTA can provide mechanistic understanding of coronary artery disease and associated prognosis. The role of HDL-C in the pathogenesis of atherosclerosis is not well understood in statin-treated patients with elevated TGL. We sought to examine the association of HDL-C levels with baseline coronary plaque volumes, namely total plaque (TP) and total non-calcified plaque (TNCP) volumes by CCTA in participants enrolled in the EVAPORATE trial.
Methods: We analyzed 80 participants who were enrolled in the trial. Linear regression analysis as a univariate and multivariate model adjusted for significant cardiovascular risk factors was performed to evaluate independent association of HDL-C and baseline coronary plaque volumes. In an exploratory analysis, stratified by sex, we compared the association of serum HDL-C levels with baseline coronary plaque volumes in males and females.
Results: Mean (SD) age of participants (n = 80) was 57.1 (8.6) years and 43% were male. Median (Inter Quartile Range/IQR) log-TNCP volume was 83.0 (0.1-7.3) mm3 and median (IQR) log-TP volume was 144.8 (0.1-7.1) mm3. After adjustment for relevant clinical covariates including age, gender, BMI, hypertension, diabetes, past smoking and baseline TGL levels, increasing levels of HDL-C remain independently associated with lower baseline log-TNCP volumes (β: 0.043 ± 0.021, p = 0.042) and baseline log-TP volumes (β: 0.046 ± 0.022, p = 0.035) on CCTA. On stratifying by sex in a multivariable regression analysis, HDL-C levels were inversely associated with baseline log-TNCP volumes (β: 0.066 ± 0.026, p = 0.018) and log-TP volumes (β: 0.077 ± 0.025, p = 0.004) in females, but not in males (log-TNCP volumes β: 0.038 ± 0.034, p = 0.282) and log-TP volumes (β: -0.033 ± 0.036, p = 0.364).
Conclusions: In a cohort of statin treated patients with known atherosclerosis and residually elevated TGL, there was a significant inverse relationship between HDL-C levels and baseline coronary plaque, TP and TNCP volumes on CCTA. Our findings provide more detailed mechanistic evidence regarding the protective role of HDL-C in coronary atherosclerosis in a high-risk cohort. Further investigation to evaluate the interaction of HDL-C levels and coronary plaque volumes on differential CVD risk in statin-treated patients with elevated TGL levels is warranted.
Keywords: Atherosclerosis; CT angiography; Dyslipidemia; HDL-C levels; Sex differences.
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