Israel Medical Association Journal

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[1].

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 MI[2] 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 MI than in those without (115.2 ± 38.5 vs. 162.7 ± 48.9 minutes, P = 0.04). Further, Tmax and MDA[3] 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 MI.

Conclusions: These findings indicate the presence of increased oxidative stress in hemodialysis patients with a history of MI.

Background: Decreased elasticity of the aorta is associated with aging and several risk factors of atherosclerosis. The data regarding this phenomenon in patients with familial hypercholesterolemia are rather sparse.

Objectives: To evaluate non-invasively the elasticity of the proximal ascending aorta of 51 heterozygous FH[1] patients compared to 42 normal age and gender-matched controls.

Methods: Aortic elasticity was estimated by transthoracic echocardiography using the “pressure-strain” elastic modulus and aortic strain formulas.

Results: The elastic modulus score was higher in the FH group than in the controls (1.12 ± 0.91 10⁶ dynes/cm² vs. 0.65 ± 0.46 10⁶ dynes/cm² respectively, P = 0.01). This was consistent in both the pediatric (0.5 ± 0.2 10⁶ dynes/cm² vs. 0.4 ± 0.1 10⁶ dynes/cm² respectively, P = 0.009) and adult subgroups (1.3 ± 1.0 10⁶ dynes/cm² vs. 0.8 ± 0.5 10⁶ dynes/cm² respectively, P = 0.0004). Aortic strain was significantly lower in patients with FH than in controls (6 ± 4% vs. 9 ± 5% respectively, P = 0.0002). These findings reflected decreased elasticity of the proximal ascending aorta in the FH patients. In multivariate analysis, age, serum cholesterol level and serum triglycerides level were the independent predictors of the elastic modulus score, whereas age was the predictor of aortic strain.

Conclusions: The elasticity of the proximal ascending aorta is decreased in heterozygous FH patients.