Análisis comparativo de la defensa antioxidante en cirugía cardíaca con y sin circulación extracorpórea

Introduccion y objetivos. Durante la cirugia cardiaca se produce una isquemia miocardica transitoria que implica el desarrollo de fenomenos de estres oxidativo con liberacion de radicales libres. El dano resultante puede ser menor si se obvia el bypass aortopulmonar. Se estudia el sistema antioxidante del glutation como medida indirecta del dano oxidativo asociado con la cirugia cardiaca. Se analiza la influencia del empleo de circulacion extracorporea. Pacientes y metodo. Se incluye a 19 pacientes en los que se realizo cirugia cardiaca, 9 de ellos con bomba (47,4%). De cada paciente se extrajeron muestras sanguineas en diferentes momentos (intraoperatorios y postoperatorios) y en ellas se cuantificaron el glutation (total, oxidado y reducido) plasmatico e intraeritrocitario y se determino la actividad enzimatica implicada (glutation-peroxidasa, glutation-reductasa y glutation-transferasa). Resultados. El glutation total disminuyo mas en los pacientes operados con circulacion extracorporea. Tambien se redujo el glutation oxidado plasmatico 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 enzimatica entre ambos grupos. Conclusiones. En nuestra serie, los pacientes intervenidos sin circulacion extracorporea mostraron un mejor perfil antioxidante en relacion con el sistema del glutation. Esto puede traducirse en que la cirugia cardiaca sin bomba resulta menos agresiva para el miocardio. Palabras clave: Defensa antioxidante. Cirugia cardiaca. Estres oxidativo. Glutation. Isquemia-reperfusion. Radical libre. Comparative Analysis of Antioxidant Defense During On-Pump and Off-Pump Cardiac Surgery 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.