General anesthesia with thoracic epidural anesthesia in the cardiopulmonary bypass surgery reduces apoptosis by upregulating antiapoptotic protein Bcl-2

Abstract

Aim. The aim of the paper was to investigate whether thoracic epidural anesthesia (TEA) together with general anaesthesia (GA) play a role on apoptosis in humans before cardiopulmonary bypass (CPB) before aortic cross clamp (ACC) and at 15 min after ACC release (after ischemia and reperfusion). Methods. Eighty patients scheduled for elective CABG were randomized to receive either GA group (n: 40) or TEA+GA group (n: 40). The right atrial biopsy samples were taken before CPB before ACC and at 15 min after ACC release from all patients. Human heart tissues were obtained from patients of TEA+GA group and GA group. The number of Bcl-2 positive cardiomyocytes was counted in multiple tissue sections of biopsies of 80 patients using fight microscopy (magnification X 40) with an ocular micrometer system (Olympus). Results. In the TEA+GA group the Bcl-2 positive cardiomyocytes were distinctly statistically increased compared to the GA group (P<0.001). in addition the intensity of the immunostaining was also increased in the TEA+GA compared with the GA group. The number of immunoreactive cardiomyocytes is as follows: before CPB TEA+GA group 396 61 GA group 92 41 before ACC TEA+GA group 333 47 GA group 94 18 at 15 min after ACC release TEA+GA group 346 +/- 68.8 GA group 85 +/- 9.5. There were statistically significant differences between groups (P<0.001). Between groups at 4 h and at 24 h after the end of CPB in the TEA+GA group the Cl was significantly higher than GA group respectively

(3.4 +/- 0.8 L/min/m(2) vs 2.5 +/- 0.8 L/min/m(2)

p<0.001) (3.8 +/- 1.1 L/min/m(2) vs 3.1 +/- 1.1 L/min/m(2)

P<0.008). Within groups at 4 and 24 h after the end of CPB in the TEA+GA group the Cl was significantly higher than baseline values respectively (3.4 +/- 0.8 L/min/m(2) vs 2.4 +/- 0.7 L/min/m(2)

P<0.001) (3.8 +/- 1.1 L/min/m(2) vs 2.4 +/- 0.7 L/min/m(2)

P<0.001). Whereas no difference was found in the GA group respectively (2.6 +/- 0.8 L/min/m(2) vs 2.5 +/- 0.8 L/min/m(2)

P>0.05) (2.6 +/- 0.8 L/min/m(2) vs 3.1 +/- 1.1 L/Min/m(2)

P>0.05). The number of patients showing ventricular fibrillation (VF) atrial fibrillation or heart block after release of the ACC was 11 of 40 (27.5%) in the TEA+GA group versus 25 of 40 (62.5%) in the GA group. The number of patients showing VF after release of ACC was 9 out of 20 patients (22.5%) in the TEA+GA group which was significantly lower than in the GA group (21 of 40 patients 52.5%)

(P<0.006). Sinus rhythm after release of ACC in the TEA+GA group was observed in 29 of 40 patients (72.5%) and was significantly higher than in the GA group (15 of 40 patients 37-5%)

(P<0.002). Conclusion The result of the present study indicate that TEA plus GA in coronary surgery had preserved cardiac function during intraoperative and postoperative period by means of reduced apoptosis improved hemodynamic function and reduced arrhythmias after release of the ACC.