Although the interaction between Hcy, NO2- and vascular disease has been extensively studied, there are no data verifying their ratios to HDL-C in coronary artery disease (CAD). We examined whether Hcy/HDL-C and NO2-/HDL-C ratios correlated with the degree of stenosis in CAD. Also, TC/HDL-C and LDL-C/HDL-C ratios were evaluated in the same individuals. Seventy subjects were divided into three groups according to coronary angiography findings: >50% stenosis (n=35, years: 50.9+/-3.4; Group 1), 5-50% stenosis (n=20, years: 50.6+/-3.8; Group 2), <5% narrowing (n=15, years: 49.0+/-3.2; control group). Hcy/HDL-C, NO2-/HDL-C, TC/HDL-C and LDL-C/HDL-C were statistically higher in both Group 1 patients (p=0.001, for all ratios) and Group 2 patients (p=0.001, p=0.001, p=0.03, 0.041, respectively) with respect to controls. The values were correlated with the degree of stenosis in the different significance levels (r=0.496, p=0.001; r=0.384, p=0.004; r=0.334, p=0.012; r=0.321, p=0.016, respectively). In patients with >50% stenosis, NO2-/HDL-C was only shown to change significantly in relation to obstructive artery number (p=0.026) and also showed a positive correlation (r=0.379, p=0.032). In conclusion, Hcy/HDL-C and NO2-/HDL-C appear to be more indicative than TC/HDL-C and LDL-C/HDL-C in the evaluation of CAD patients regarding the degree of stenosis. However, only NO2-/HDL evaluation seems to be a reliable indicator in the patients with heavy stenosis of CAD. Further studies are needed to confirm the results of present study. (C) 2004 Elsevier Inc. All rights reserved.