ABC | Volume 114, Nº3, March 2020

Original Article Kurmus et al. Discordance of lipoproteins and CAD severity Arq Bras Cardiol. 2020; 114(3):469-475 Table 1 – Baseline characteristics of the study population Characteristics Clinical characteristics Male gender (%) 57.5 Age in years (mean ± standart deviation) 61.1 ± 11.4 Smoking (%) 32.1 Hypertension (%) 49.6 Diabetes (%) 30.1 BMI (kg/m 2 ) (mean ± standart deviation) 28.8 ± 4.1 Statin usage at admission (%) 33.3 Biochemical analysis (mean ± standart deviation) Total cholesterol (mg/dl) 198.5 ± 49.1 LDL-C (mg/dl) 117.4 ± 38.2 HDL-C (mg/dl) 41.8 ± 11.3 Triglyceride (mg/dl) 163.2 ± 84.2 Non-HDL-C (mg/dl) 156.7 ± 46.8 Fasting glucose (mg/dl) 114.6 ± 40.9 Creatinine (mg/dl) 0.95 ± 0.48 CAD severity Mean Gensini score 25.3 ± 39.6 Median Gensini score (interquartile range) 12 (31.1) Mean SYNTAX score 7.1±10.2 Median SYNTAX score (interquartile range) 4 (11.0) CAD: coronary artery disease; LDL-C: low-density lipoprotein cholesterol; HDL-C: high-density lipoprotein cholesterol; Non-HDL-C: non-high-density lipoprotein cholesterol; BMI: body mass index. non-HDL-C<median, group2: LDL-C<median andnon‑HDL-C ≥median, group 3: LDL-C≥median and non‑HDL-C<median, group 4: LDL-C≥median and non-HDL-C≥median. Groups 2 and 3 were discordant groups (Table 2). The variables age, BMI, smoking history, and percentage of patients with hypertension were not different between groups. The percentages of patients with diabetes mellitus and of patients receiving statin treatment were significantly different between groups (p = 0.004 and p < 0.001, respectively). Patients in Group 2 (LDL-C <median and non-HDL-C ≥median) had the highest prevalence of diabetes mellitus and the lowest percentage of current statin treatment. The percentage of patients on statin treatment was the highest in Group 1 (LDL-C < median and non-HDL-C < median). Gender was significantly different from group to group (p = 0.036). Group 1 had the lowest percentage of females (LDL-C < median and non-HDL-C < median), while Group 4 had the highest (LDL-C ≥median and non‑HDL‑C ≥ median). Total cholesterol and LDL-C were present in high proportions in the groups with LDL-C ≥median and non‑HDL-C ≥ median, but triglycerides was the highest in the group with LDL-C < median and non-HDL-C ≥ median (p < 0.001, p < 0.001 and p < 0.001, respectively). The percentage of patients with Gensini or SYNTAX score of zero did not differ between groups (p = 0.837 and p = 0.821, respectively). Mean Gensini and SYNTAX scores, percentage of patients with Gensini score ≥ 20 and SYNTAX score > 22 were also not different between groups (p = 0.635, p = 0.733, p = 0.799 and p = 0.891, respectively). There was also no statistically significant correlation between LDL-C and Gensini or SYNTAX scores in any of the 4 subgroups. Additionally, no correlation was found between non-HDL-C and Gensini or SYNTAX scores in subgroups (Table 3). Discussion In the present study, we assessed the cross-sectional association between CAD severity/complexity and discordance between LDL-C and non-HDL-C numbers. While discordance was present between LDL-C and non-HDL-C in patients submitted to coronary angiography (15% of the sample), there was no difference regarding CAD severity and complexity between discordant and concordant groups. Non-HDL-C represents the cholesterol content of all circulating atherogenic lipoproteins and it is not influenced by fasting conditions. Several studies have indicated that non‑HDL-C is a better predictor of cardiovascular risk and mortality than LDL-C. 4,5,12,13 It has been also reported that non‑HDL-C was more closely associated with cardiovascular events than LDL-C in patients receiving statin therapy. 3,14 There are some explanations for these states. Firstly, non‑HDL-C includes VLDL and LDL cholestrols, and VLDL is also atherogenic. 15,16 Secondly, non-HDL-C is an indirect measure of LDL-particles (LDL-p), and LDL-related atherosclerotic risk is better determined by the LDL-p number. 17-19 Finally, non‑HDL-C is correlated with the Apolipoprotein B (ApoB). 20 ApoB carrying lipoproteins initiate and maintain the atherosclerotic process by entering and trapping within the arterial wall, so the total number of ApoB particles is a critical determinant of cardiovascular risk. 5,21-23 To calculate non-HDL-C, no additional measurement beyond the routine lipid parameters is required, so no additional expense is made, which is an advantage for non-HDL-C over apoB. LDL-p may be cholesterol-depleted or enriched. This variation causes discordance between LDL-C and non‑HDL-C. The discordance rate in our study is similar to that of previous studies. In a study with 27,533 participants, prevalance of discordance was 11,6% and, in another study with 1,757 patients, it was 14.6 %. 7,8 Also in a study conducted with aproximately 1.3 million adults, a similar discordance rate (15%) was found, especially at lower LDL levels. 24 Discordance is high among subjects with high triglycerides level, lower HDL-C, dysglycemia and obesity. 7,25,26 Coronary risk was found to be either underestimated or overestimated by LDL-C in individuals presenting discordance. 7 Both LDL-C, non-HDL-C and discordance in relation to future cardiovascular events were evaluated in several studies. However, data about lipid parameters or discordance accurately predicting the severity or complexity of coronary atherosclerosis are limited and also contraversial. In a study by Budde et al., 27 there was no relation between LDL-C and number, severity, and lenght of coronary lesions. 27 Also, there was no relationship between LDL-C and coronary plaque volume, 3-vessel or left main coronary disease and 471