Oxidative stress and inflammatory response increase during coronary artery bypass grafting with extracorporeal circulation.

Introduction: Thiobarbituric acid-reactive substance is a marker of oxidative stress and has cytotoxic and genotoxic actions. C- reactive protein is used to evaluate the acute phase of inflammatory response.

Objectives: To assess the thiobarbituric acid-reactive substance and C-reactive protein levels during extracorporeal circulation in patients submitted to cardiopulmonary bypass.

Methods: Twenty-five consecutive surgical patients (16 men and nine women; mean age 61.2 ± 9.7 years) with severe coronary artery disease diagnosed by angiography scheduled for myocardial revascularization surgery with extracorporeal circulation were selected. Blood samples were collected immediately before initializing extracorporeal circulation, T0; in 10 minutes, T10; and in 30 minutes, T30.

Results: The thiobarbituric acid-reactive substance levels increased after extracorporeal circulation (P=0.001), with average values in T0=1.5 ± 0.07; in T10=5.54 ± 0.35; and in T30=3.36 ± 0.29 mmoles/mg of serum protein. The C-reactive protein levels in T0 were negative in all samples; in T10 average was 0.96 ± 0.7 mg/dl; and in T30 average was 0.99 ± 0.76 mg/dl. There were no significant differences between the dosages in T10 and T30 (P=0.83).

Conclusions: C-reactive protein and thiobarbituric acid-reactive substance plasma levels progressively increased during extracorporeal circulation, with maximum values of thiobarbituric acid-reactive substance at 10 min and of C-reactive protein at 30 min. It suggests that there are an inflammatory response and oxidative stress during extracorporeal circulation.