Serum lipids, lipoprotein(a) and apo(a) isoforms in patients with established coronary artery disease and their relation to disease and prognosis after coronary by-pass surgery Original Research Article

Consecutive patients (n=964) undergoing coronary angiography were studied and compared with a random population sample regarding serum lipids and lipoproteins with focus on lipoprotein(a) (Lp(a)) levels and apo(a) isoforms. The patients were also followed for 5 years after the angiography, and the progostic value of serum lipoproteins were analyzed. The patients were divided in two groups: Group 1 (n=814) consisted of patients with angina pectoris and at least one coronary artery with 50% stenosis and group 2 (n=150) patients with none of the coronary arteries significantly obstructed (<50%). As controls a random population sample was selected (n=197). Blood samples were collected before coronary angiography for determination of serum lipids, Lp(a) and isoforms of apo(a). When group 1 and group 2 patients were compared, group 1 was found to have higher serum cholesterol, triglycerides, apoB and Lp(a) as well as lower HDL and apoAI. When group 1 was compared with the random sample, after correction for age and sex, similar differences were observed, except that the difference in Lp(a) was not significant. The high Lp(a) levels among patients was found to be primarily due to the female patients, where the difference compared to both group 2 and controls was highly significant (P=0.007 and P=0.001, respectively). There was a significant difference in the apo(a) isoform distribution between group 1 patients and control subjects (P=0.0003), with a higher frequency of low molecular weight isoforms among patients. This was also significant for the male subgroup (P=0.001). Lp(a), LDL, total cholesterol, triglycerides, apoB, HDL and apoAI were significantly related to the number of major coronary arteries with >50% stenosis. Mortality during follow-up was,in a univariate analysis, significantly correlated to several factors related to the degree of heart disease and to LDL (P=0.02) and apoB (P<0.01). Increased mortality was, however, related to low levels of apoB and LDL. For cardiac mortality no significant correlation to lipoprotein variables were found. In conclusion established lipoprotein risk factors were more frequent among patient with angina pectoris and verified coronary stenosis. Furthermore high Lp(a) levels and a high frequency of low molecular weight isoforms of apo(a) were found in coronary patients. Higher Lp(a) levels were observed both for female and male patients, the differences were, however, significant only for the female patients. None of the lipoprotein variables could predict coronary death during the follow-up period.