Enhanced lipid peroxidation in patients during coronary artery bypass grafting.

Lipid peroxidation products were measured at various time intervals in 20 patients with coronary artery disease, who underwent coronary artery bypass graft (CABG) surgery. Post-operative blood lipid peroxides were found to be significantly higher (p < 0.001) than the preoperative value. Lipid peroxides raised to a peak value of 46.42 +/- 12.86 n mol/g Alb at 5 min of reperfusion when compared to the basal value and afterwards the level declined to 41.02 +/- 7.09 at 2 hrs and remained in that level even at 24 hrs of reperfusion. This increase implies an enhancement in free radical mediated oxidation of membrane lipids during bypass surgery and thus provides evidence for free radical generation during myocardial reperfusion.

Distribution of cholesterol in HDL and its subfractions in patients with coronary atherosclerotic heart disease.

The distribution of HDL-C and its subclasses HDL3-C and HDL2-C and other serum lipids was studied in patients with coronary atherosclerotic heart disease grouped as young males (group 1) and older males (group 2) along with age matched controls. All the patients had significantly higher levels of serum cholesterol, triglycerides, LDL-C and VLDL-C and lower levels of HDL-C. The analysis of HDL - subclasses clearly demonstrated that the low levels of HDL-C was due to the significant decrease of cholesterol in both HDL3 (group 1: 32%; group 2: 30%) and HDL2 subclasses (group 1: 55%; group 2: 48%) compared to the respective control values. Further it has also been observed that this low level of HDL-C is a characteristic feature of patients irrespective of whether the levels of serum cholesterol and triglycerides are high or normal. Although both the HDL subclasses were decreased, the percentage of reduction of cholesterol was greater in the HDL2 than in HDL3 subclass. In addition, the levels of cholesterol either in HDL or any of its subclasses, HDL3 and HDL2 did not show any change in relation to the extent of coronary disease which was assessed by coronary angiography. This study confirms the inverse relation of HDL-C with coronary atherosclerosis and also indicates that, of all the lipid parameters examined, only HDL-C, particularly its subclass HDL2-C, shows independent inverse relation to the incidence of coronary atherosclerotic artery disease in men.