Lipids and lipoproteins in patients undergoing coronary-artery surgery

Fasting blood samples were obtained from 290 patients who were undergoing elective coronary-artery graft procedures, and cholesterol, triglyceride and high-density lipoprotein cholesterol levels were measured. The 1983 National Heart Foundation of Australia's Risk Factor Prevalence Study was used as a source of age- and sex-matched "control" data. Of these patients, 80% had cholesterol levels of greater than 5.5 mmol/L; in 55% of patients, the level exceeded 6.5 mmol/L. Only 4% of patients who received a graft showed hypertriglyceridaemia alone (triglyceride level, greater than 2 mmol/L). Combined hyperlipidaemia (cholesterol level, greater than 5.5 mmol/L and triglyceride level, greater than 2.0 mmol/L) was present in 52% of subjects. Low-density lipoprotein cholesterol levels exceeded 3.5 mmol/L in 69% of men and in 71% of women. In terms of five 10-year age intervals, mean plasma triglyceride and cholesterol levels were elevated significantly in patients who had undergone a coronary-artery grafting procedure compared with those of subjects in the National Heart Foundation study. The mean high-density lipoprotein cholesterol levels were markedly-lower compared with those of the subjects in the National Heart Foundation study. Of those patients whose plasma cholesterol levels were less than 5.5 mmol/L, 97% of patients had high-density lipoprotein cholesterol levels that were less than the mean level for subjects in the National Heart Foundation study. Thus, a very-high proportion of patients who underwent coronary-artery bypass surgery had lipid abnormalities which required intervention postoperatively.