Prospective evaluation of hydroperoxide plasma levels and stable nitric oxide end products in patients subjected to angioplasty for coronary artery disease

Background: Oxidative stress appears to be involved in several processes that contribute to atherogenesis and restenosis following vascular intervention. Methods: The aim of our study was to evaluate prospectively the plasma concentrations of a hydroperoxide (ROOH) and nitric oxide end product (NOx) in patients subjected to coronary angioplasty (PTCA) and routine control angiography 6 months after the initial procedure. We prospectively studied 48 consecutive patients (39 men, nine women, mean age 52 years) with stable angina who underwent successful elective angioplasty. A vascular segment was considered successfully treated when the residual luminal narrowing in the dilated segment immediately after angioplasty was <50%. Angiographic follow-up was obtained in all of the patients. Plasma samples were drawn at baseline (before angioplasty) and serially after angioplasty (1, 3 and 6 months afterwards). Hydroperoxides were determined by the FOX II assay (ferrous oxidation in xylenol orange, Pierce Rockford, IL). Nitrate was converted in the presence of NO3 reductase. The Griess reagent was used for the measurement of NO2. Results: The overall angiographic restenosis rate was 35%. There were no significant differences in clinical variables between the patients with or without restenosis. The baseline levels (0.8±0.09 vs. 0.6±0.2 μmol/l) as well as the concentrations of authentic lipid hydroperoxide in plasma after 1 month (0.7±0.09 vs. 1.0±0.2 μmol/l) and 6 months (0.8±0.1 vs. 1.0±0.2 μmol/l) were similar in both groups. Three months after the angioplasty a significant increase in the ROOH level was noticed in the patients with restenosis (0.9±0.1 vs. 1.4±0.2, P=0.04). Plasma levels of NOx were similar in both groups at baseline (23.6±2.1 vs. 22.7±2.6 μmol/l) and 1 month after procedure (24.4±2.2 vs. 23.4±3.3 μmol/l). However, in patients with restenosis significant decreases in stable NO end products were observed 3 and 6 months after PTCA (18.1±1.5 vs. 13.3±1.7, P=0.04; 14.2±1.0 vs. 8.7±1.3, P=0.02, respectively). Conclusions: In patients with angiographic restenosis a significant increase in lipid peroxidation accompanied by a reduction in the stable end products of nitric oxide in plasma is observed several months after PTCA.