Study Of The Effects Of Cardiopulmonary Bypass In High Altitude Areas On Injury Or Activation Of Endothelial Cells

Objective: A lot of previous studies showed that cardiopulmonary bypass could induce injury or activation, and dysfunction of endothelial cells. The recent study also suggested that hypoxia in high altitude areas could induce injury and dysfunction of endothelial cells. This study was designed to observe the changes of circulating endothelial cells (CEC), plasma endothelin-1 (ET-1), nitrogen monoxidum (NO), prostacyclin 12 (PGI2) during cardiopulmonary bypass under the condition of high altitude areas to investigate the effects of cardiopulmonary bypass on injury or activation of endothelial cells.Methods: A total of 15 patients with congenital heart diseases undergoing cardiac operations were enrolled into the study. Of them, 11 patients with CPB were subjected into Group CPB, and 4 patients received ligation of PDA through thoracotomy into the control (Group NCPB). Group CPB were made up of 5 high-altitude inhabitant patients and 6 high-altitude immigrant patients. Blood samples in Group NCPB were collected in anesthesia-induction period (= baseline), after opening thorax, before closing thorax, and at 2,4, and 24 h after operation. Blood samples in Group CPB were collected in anesthesia-induction period, at CPB 15 min and the end of CPB, and at 2, 4, and 24h after termination of CPB. CEC count was conducted, and the plasma levels of ET-1, NO, and PGI2 were measured respectively.Results: (1). There was no significant change in CEC count, plasma levels of ET-1, NO, and PGI2 in Group NCPB. (2). CEC count and plasma levels of ET-1 and PGI2 were significantly elevated during CPB in group CPB, but decreased after CPB. However, no significant change in plasma NO was found till 24 h after termination of CPB. (3). After CPB, CEC count, plasma levels of ET-1 and PGI2 decreased significantly. At 24 h after termination of CPB, CEC count in high-altitude patients was recovered, but plasma NOincreased significantly. In high-altitude immigrant patients, CEC count, plasma levels of ET-1 and PGI2 decreased slowly after CPB, but no significantly change was found in plasma levels of NO.Conclusion: Our results suggest that CPB in high altitude areas can induce activation/damage of vascular endothelial cells, increase of circulating endothelial cells, disequilibrium of plasma ET-1/NO, and increase of plasma prostacyclin 12. Moreover, injury of endothelial cells during CPB in high-altitude immigrant patients is more severe than that in high-altitude inhabitant patients. The lasting time of the injury of endothelial cells in high-altitude immigrant patients is longer than that in high-altitude inhabitant patients. Management with prostacyclin during CPB might have the protective effect on the endothelial cells.