Does cardiopulmonary bypass increase Lipoprotein (a) levels more in hypercholesterolemic patients compared to normocholesterolemic patients?
Cardiopulmonary bypass induces a significant acute-phase increase in Lipoprotein (a) levels, which is more pronounced in patients with baseline hypercholesterolemia.
Increments of lipoprotein (a) (Lp (a)) concentration during cardiopulmonary bypass (CPB) have not been justified in the literature yet. We have investigated whether Lp (a) levels remain constant or increase during CPB and if high plasma levels of low density lipoprotein (LDL; containing apolipoprotein (apo) B) in hypercholesterolemic patients affect the assembly of Lp (a) (containing apoB: Apo (a)). In this study, the change in plasma lipid and lipoprotein levels of 40 patients with hypercholesterolemia and 40 patients who have normal cholesterol values were determined and compared during CPB, and in the postoperative early stage. In our study, lipid and lipoproteins, except Lp (a), showed a falling trend and paradoxically, Lp (a) statistically showed a significant rising trend, like the acute phase reactant in two groups (p=0.011 for LDL, p=0.016 for high density lipoprotein (HDL) and p<0.001 for the others, in 80 patients). Concentrations of Lp (a) in plasma increased more sharply in the hypercholesterolemic group than the normocholesterolemic group during CPB. This difference was significant at the 60th minute of cardiopulmonary bypass with a nonparametric test (p<0.05 Mann-Whitney U test). High density lipoprotein values showed more decline in the hypercholesterolemic group patients than in the normocholesterolemic group patients (p<0.05). In conclusion, lipoprotein (a) levels increased more pronounced in patients with hypercholesterolemia during CPB. On the other hand, high LDL levels in hypercholesterolemic patients accelerated Lp(a)formation in the acute phase.
Güvener et al. (Mon,) studied this question.