Levels of serum lipids, apolipoproteins A-I and B and pseudocholinesterase activity and their discriminative values in patients with coronary by-pass operation.

Serum lipids and apoproteins A-I and B were measured in 115 male patients and serum pseudocholinesterase activity (PChE) was determined in 83 patients with 3 vessel coronary artery disease (CAD). The control subjects were matched according to sex, smoking, relative weight and age and were free from heart disease. The CAD patients had significantly higher serum VLDL cholesterol and triglyceride levels and lower HDL cholesterol and apo A-I levels and lower HDL to total cholesterol ratio than the controls. The concentrations of serum total cholesterol and LDL cholesterol were only slightly (6.4% and 8.8%, on an average) higher in CAD patients than in controls. The apo B levels of CAD patients were also slightly lower in patients than in controls. The CAD patients had slightly higher PChE activities than controls. The ratios of apo A-I to PChE and HDL cholesterol to PChE were significantly (about 30%, P less than 0.001) lower in patients than in controls. In discriminant analysis between the groups HDL cholesterol and apo A-I showed the best (74% success in reclassifying the patients to correct groups), and total cholesterol, triglycerides, LDL cholesterol and apo B remarkably weak discriminating power among the single variables of serum lipids and lipoproteins. In discriminating analysis the apo A-I/PChE and HDL cholesterol/PChE ratios showed relatively high (77.1 and 71.1% success from the patients to correct groups) and serum PChE activity weak discriminating power. These results indicate that low levels of HDL cholesterol and apo A-I and the low ratio of HDL cholesterol to total cholesterol are the most potent metabolic risk factors for 3 vessel coronary artery disease in a population with relatively high serum total cholesterol level. The determinations of apo A-I/PChE and HDL cholesterol/PChE ratios may be an additional, valuable tool in discriminating the risk for CAD.