Antioxidant Action of Vitamins A and E in Patients Submitted to Coronary Artery Bypass Surgery

Sixteen patients submitted to coronary artery bypass grafting were divided into two groups: Group 1 served as controls, and patients in Group 2 received 400 mg of vitamin E and 100,000 IU of vitamin A orally each day for five days before surgery. During surgery biopsy samples were obtained from the apex of the left ventricle before the ischemic period and after ten minutes of reperfusion. The samples were assayed for hydroperoxide-initiated chemiluminescence to indirectly determine free radicals activity. Preischemia biopsy specimens showed a photoemission of 40.7±1 cpm/mg of protein x 10-3, and 33.0±6.3 cpm/mg of protein x 10-3 for Groups 1 and 2 respectively (p NS). For rerperfusion samples the values were 89.5±11 cpm/mg of protein x 10 -3 and 23.9 ± 5 cpm/mg of protein x 10-3 for Groups 1 and 2 respectively (p<0.001). These results show that the ischemia/reperfusion mechanism increases oxidative stress and this unwished effect may be inhibited with the preoperative administration of vitamins A and E.