Fasting Remnant Lipoprotein Particle Cholesterol And The Severity Of Coronary Atherosclerosis Among Subjects Without Statin Treatment

Objective: To investigate the correlation between the level of fasting remnant lipoprotein particle-cholesterol(RLP-C)and the severity of coronary atherosclerosis and inflammatory indicators among the population with LDL-C <1.8mmol/L and glycosylated hemoglobin <7%.Metheds: We enrolled 1988 consecutive subjects with suspected coronary atherosclerosis for elective coronary angiography in our institution(Shengjing Hospital affiliated to China Medical University)from January 2012 to December 2017.The severity of coronary atherosclerosis was quantified by Gensini System(GS)Score.RLP-C= TC-LDL-C-HDL-C.All the subjects were divided into group one(GS score= 0)and group two(GS score>0),then group two further divided into four groups according to interquartile of GS score.Continuous data were using one way analysis of variance(normal distribution data)and Kruskal Wallis H tests(skewed distribution data)as appropriate.The categorical variables were compared by chi-squared tests.The relationships between the variables and GS score were assessed by Spearman rank correlation(non-parametric data)and Pearson correlation(paremetric data).Multiple linear regression analysis was used to assess the independent contribution of the variables.The association between RLP-Cand high GS score was tested using univariate and multivariate logistic models,reporting odds ratios(OR)with 95% confidence intervals(95%CI).We examined the levels of white blood cells as potential mediators of the relationship between RLP-C and GS score using a causal mediation analysis.A P value of less than 0.05 was considered statistically significant.Results: The RLP-C levels of five groups were gradually increased,which were0.55±0.35,0.59±0.41,0.65±0.42,0.68±0.43,0.74±0.89mmol/L,P<0.001.RLP-C level was positively correlated with GS score: r=0.091,P<0.001,even after adjusted for age,gender,smoking,systolic blood pressure,HbA1 c,and inflammatory indicators(?=0.069,P=0.003).The multivariatelogistic regression analysis showed that,after adjusted for age,gender,smoking,blood pressure,HbA1 c,BMIand inflammatory indicator,RLP-C level(per 1 mmol/L increase)was significantly associated with a greater risk of high GS score(OR=1.745,95%CI1.338-2.257,P<0.001).However,increased LDL-C level did notincrease the risk of high GS score(OR=1.027,95%CI 0.913-1.155,P=0.656).Further analysis of the correlation between RLP-C level and GS score in subjects with LDL-C<1.8mmol/L,showed that RLP-C level was still positively correlated with GS score(r=0.223,P=0.001),even after adjusted for other risk factors(?=0.219,P=0.001);but there was no significant correlation between LDL-C and GS score(r=-0.058,P=0.383).Multivariate logistic regression analysis showed that after adjusted for other risk factors,RLP-C level(per 1 mmol/L increase)was significantly associated with a greater risk of high GS score(OR=1.980,95%CI1.212-3.235,P=0.006),while elevated LDL-C level did not increase the risk of high GS score(OR=1.058,95%CI 0.287-3.907,P=0.933).We also found that for the population with HbA1c<7%,RLP-C was significantly correlated with GS score(r=0.086,P=0.001),even after adjusting for other risk factors(?=0.090,P<0.001);But LDL-Clevel was not significantly correlated with GS score(r=0.018,P=0.491);Multivariate logistic regression analysis showed that after adjusted for other risk factors,RLP-C level(per 1mmol/L increase)was significantly associated with a greater risk of high GS score(OR=1.883,95% CI 1.369-2.592,P<0.001),while elevated LDL-C leveldid not increase the risk of high GS score(OR=0.956,95%CI 0.838-1.090,P=0.500).Conclusion: There was a significant positive correlation between the level of fasting RLP-C and the severity of coronary atherosclerosis.The higher level of RLP-C,the higher risk of high GS score.Inflammatory reaction was involved in the influence of RLP-C on the severity of coronary atherosclerosis.Elevated RLP-Clevels were associated with a significantly increased risk of severe coronary atherosclerotic even in those population with LDL-C<1.8mmol/L or HbA1c<7%,and it is a better risk predictor of cardiovascular diseasecompared with LDL-C.