A study of lipid profile before and after coronary artery bypass grafting

This study was undertaken to establish the variability in the levels of total cholesterol (TC), total triglyceride (TG), low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol before and after coronary artery bypass graft (CABG) surgery, in order to determine postoperatively when an accurate assessment can be made of the lipid status. During a prospective study over 4 months, fasting venous samples were taken pre- and postoperatively on day 5, and in the 4th, 8th and 12th weeks. Ninety-six patients admitted to the cardiothoracic and cardiac wards for CABG were recruited to the study. The mean preoperative levels were: TC 5.94 (+/- 0.1 mmol/l), LDL cholesterol 4.02 (+/- 0.05mmol/l) and HDL cholesterol 1.00 (+/- 0.03mmol/l). These were significantly different (p<0.01) from the levels on the 5th postoperative day when the mean level of TC was 4.14 (+/- 0.084mmol/l), LDD cholesterol was 2.45 (+/- 0.07mmol/l) and HDL cholesterol was 0.74 (+/- 0.03mmol/l). By the 4th postoperative week, mean TC (5.73 +/- 0.13mmol/l), LDL cholesterol (3.79 +/- 0.14mmol/l) and HDL cholesterol (1.03 +/- 0.04mmol/l) did not vary significantly from the mean preoperative values. There was no significant difference in the mean TG levels pre- and postoperatively. The mean TC, LDL cholesterol and HDL cholesterol rise to preoperative levels by the 4th week after CABG. Thus, an accurate assessment of patients' lipid status can be made from this period. An earlier postoperative assessment may be falsely reassuring.