The Effect of Cardiopulmonary Bypass and Hypothermic Circulatory Arrest on Hepatic Histology in Newborn Animals: An Experimental Study

Still little is known about the effect of cardiac surgery on neonatal hepatic tissue. We examined the effect of cardiopulmonary bypass (CPB) and the effect of deep hypothermic circulatory arrest (DHCA) on neonatal hepatic tissue. Liver biopsies of neonatal piglets were taken after CPB (n=4), after DHCA (n=5), and after surgery without CPB (non-CPB; n=3). Additionally, findings were compared to those of control piglets (n=9). The liver specimens were fixed, stained with hematoxylin and eosin, and scored regarding inflammatory reaction, hepatocellular edema, and apoptosis. Inflammation score of treated groups was higher than in control; CPB 2.5+/-0.5, DHCA 1.6+/-0.4, non-CPB 1.2+/-0.6, control 0.4+/-0.3 (P<0.001 CPB and DHCA vs. control; P<0.05 non-CPB vs. control). Hepatic cell edema was more evident after DHCA (score 2.0+/-0.4 vs. 0.2+/-0.3 in control and 0.6+/-0.5 after CPB; P<0.001 and P<0.05, respectively). The highest apoptotic cell count was in the non-CPB group (22.3+/-6.3 vs. 11.4+/-3.6 in control and 8.9+/-5.4 after CPB; P<0.05). The present study showed that (i) surgical trauma induces hepatic cell apoptosis; (ii) CPB increases hepatic inflammatory reaction; and (iii) DHCA amplifies hepatic cell edema.