Serum lipoprotein(a) concentrations and apolipoprotein(a) phenotypes in hemodialysis, chronic ambulatory peritoneal dialysis and post-transplant patients

Serum lipoprotein(a) [Lp(a)] concentrations and apolipoprotein(a) apo(a) phenotypes were determined in 81 hemodialysis (HD) patients, 37 chronic ambulatory peritoneal dialysis (CAPD) patients, 25 post-transplant patients and 99 healthy subjects as the reference group. The CAPD patients had significantly higher serum Lp(a) concentration than HD patients, but both had significantly increased Lp(a) levels as compared with the reference group and post-transplant patients. When all studied groups were divided into two subgroups with at least one low molecular weight (LMW) isoform and with only one high molecular weight (HMW) isoform, they presented a similar distribution. (Pearson's chi-squared = 2,78; df = 3; p = NS). The median serum Lp(a) levels were significantly increased with HMW class versus the reference group and post-transplant patients. In CAPD patients, the LMW phenotypes showed significantly increased median serum Lp(a) concentrations versus the reference group, but they were not statistically elevated in HD patients. In the post-transplant patients, LMW and HMW phenotypes did not differ as compared to the reference group. The elevated Lp(a) levels in HD and CAPD groups were explained by apo(a) type-specific, but not by differences in, isoform frequencies. We conclude that HD and CAPD patients had increased Lp(a) levels compared with the reference group, whereas elevated Lp(a) concentrations were observed mainly in patients with HMW apo(a) phenotypes. Patients after renal transplantation showed a correction of Lp(a) levels mainly in HMW phenotypes. The LMW status corresponding to high Lp(a) levels and apo(a) isoforms could be used together with Lp(a) levels with other risk factors to assess in uremic patients the predisposition to coronary artery disease.