[Comparative analysis of antioxidant defense during on-pump and off-pump cardiac surgery]. / Análisis comparativo de la defensa antioxidante en cirugía cardíaca con y sin circulación extracorpórea.

INTRODUCTION AND OBJECTIVES: The transient myocardial ischemia that occurs during cardiac surgery leads to oxidative stress and the production of free radicals. The resulting damage can be reduced if cardiopulmonary bypass is avoided. We obtained indirect measures of the oxidative damage occurring during cardiac surgery by monitoring the glutathione system and we studied the influence of cardiopulmonary bypass. PATIENTS AND METHOD: The study included 19 patients undergoing cardiac surgery. Cardiopulmonary bypass was used in 9 (47.4%). Blood samples were obtained from each patient at different times during and after surgery. Total, oxidized and reduced glutathione levels were measured, as was the activity of related enzymes (i.e., glutathione peroxidase, glutathione reductase, and glutathione transferase). RESULTS: The total glutathione level decreased more in patients in whom cardiopulmonary bypass had been used. In addition, the oxidized glutathione level was reduced in these patients, which suggests that antioxidant defense was not fully effective. In contrast, the oxidized glutathione level tended to increase in patients in whom cardiopulmonary bypass had not been used. There was no significant difference in enzymatic activity between the two groups. CONCLUSIONS: In this study, patients who underwent off-pump cardiac surgery had a better antioxidant profile. The implication could be that cardiac surgery without cardiopulmonary bypass has a less damaging effect on ischemic myocardium.

Análisis comparativo de la defensa antioxidante en cirugía cardíaca con y sin circulación extracorpórea / Comparative analysis of antioxidant defense during on-pump and off-pump cardiac surgery

Introducción y objetivos. Durante la cirugía cardíaca se produce una isquemia miocárdica transitoria que implica el desarrollo de fenómenos de estrés oxidativo con liberación de radicales libres. El daño resultante puede ser menor si se obvia el bypass aortopulmonar. Se estudia el sistema antioxidante del glutatión como medida indirecta del daño oxidativo asociado con la cirugía cardíaca. Se analiza la influencia del empleo de circulación extracorpórea. Pacientes y método. Se incluye a 19 pacientes en los que se realizó cirugía cardíaca, 9 de ellos con bomba (47,4%). De cada paciente se extrajeron muestras sanguíneas en diferentes momentos (intraoperatorios y postoperatorios) y en ellas se cuantificaron el glutatión (total, oxidado y reducido) plasmático e intraeritrocitario y se determinó la actividad enzimática implicada (glutatión-peroxidasa, glutatión-reductasa y glutatión-transferasa).Resultados. El glutatión total disminuyó más en los pacientes operados con circulación extracorpórea. También se redujo el glutatión oxidado plasmático e intraeritrocitario, lo que expresa una defensa antioxidante ineficaz, mientras que en los casos sin bomba esta tendencia fue creciente. No hubo diferencias significativas en la actividad enzimática entre ambos grupos. Conclusiones. En nuestra serie, los pacientes intervenidos sin circulación extracorpórea mostraron un mejor perfil antioxidante en relación con el sistema del glutatión. Esto puede traducirse en que la cirugía cardíaca sin bomba resulta menos agresiva para el miocardio

Introduction and objectives. The transient myocardial ischemia that occurs during cardiac surgery leads to oxidative stress and the production of free radicals. The resulting damage can be reduced if cardiopulmonary bypass is avoided. We obtained indirect measures of the oxidative damage occurring during cardiac surgery by monitoring the glutathione system and we studied the influence of cardiopulmonary bypass.Patients and method. The study included 19 patients undergoing cardiac surgery. Cardiopulmonary bypass was used in 9 (47.4%). Blood samples were obtained from each patient at different times during and after surgery. Total, oxidized and reduced glutathione levels were measured, as was the activity of related enzymes (i.e., glutathione peroxidase, glutathione reductase, and glutathione transferase). Results. The total glutathione level decreased more in patients in whom cardiopulmonary bypass had been used. In addition, the oxidized glutathione level was reduced in these patients, which suggests that antioxidant defense was not fully effective. In contrast, the oxidized glutathione level tended to increase in patients in whom cardiopulmonary bypass had not been used. There was no significant difference in enzymatic activity between the two groups. Conclusions. In this study, patients who underwent off-pump cardiac surgery had a better antioxidant profile. The implication could be that cardiac surgery without cardiopulmonary bypass has a less damaging effect on ischemic myocardium