Lipid oxidation kinetics in hemodialysis patients with and without history of myocardial infarction

Background: In lipid oxidation kinetics studies, prevalent cardiovascular disease has been associated with shortened lag phase, the length of time preceding the onset of oxidation. Objectives: To examine, in vitro, copper-induced lipid oxidation kinetics in unfractionated serum from hemodialysis patients and to determine differences in kinetic parameters between patients with and without a history of CVD. Methods: Of the 76 patients enrolled in a study of oxidative stress in hemodialysis (44/76 with prevalent CVD, 53/76 males), 9 males with a history of myocardial infarction were selected and matched for age, diabetes and smoking status with 9 males from the non-CVD group. The kinetics of lipid oxidation was studied. Blood chemistry determinations including serum lipids, lipoproteins, hemostatic factors and serum malondialdehyde were obtained. Variables were compared using the t-test for independent samples with history of Ml entered as the categorical variable. Results: Tmax, the oxidation kinetic parameter defined as the time at which the rate of absorbing product accumulation was maximal, was significantly shorter in dialysis patients with a history of Ml than in those without (115.2 ± 38.5 vs. 162.7 ± 48.9 minutes, P = 0.04). Further, Tmax and MDA were negatively correlated to one another (r = -0.47, P = 0.04). Odds ratios indicate that each 1 minute increase in Tmax was associated with a 3% decrease in odds that a subject had a history of Ml. Conclusions: These findings indicate the presence of increased oxidative stress in hemodialysis patients with a history of Ml.