The Effects of Heart-Lung Bypass on Endothelial Function of Patients with Open Heart Surgery

Background: Endothelium is an essential organ for maintaining an adequate vascular tone and preventing the pathological process of atherosclerosis. Heart-lung machine is a mechanical support for maintenance of blood circulation during open heart surgery. It has been shown that flow of blood through this circuit can induce complement activation, endotoxines production, and release of many inflammatory mediators. Objectives: Cardiopulmonary Bypass (CPB) has some detrimental effects on endothelial function. Flow Mediated Dilation (FMD) is also a noninvasive method for evaluation of endothelial function. Patients and Methods: This study was conducted on 22 patients who were admitted in cardiac surgery ward for open heart operation and met the inclusion criteria of the study. Brachial artery FMD was measured the day before and 2 days after CPB. Results: The mean duration of CPB was 62.95 minutes. The mean percent of FMD changes was measured and compared before and after CPB (4.29 and 0.03 vs. 1.38 and 1.99, < 0.001). The results showed a significant relationship between CPB and bronchial endothelial function. Conclusions: This study revealed the influence of CPB on endothelial function. Yet, more studies are necessary to confirm this important issue, and decline in use of CPB is appreciated.