Oxidative stress and systemic inflammatory response after cardiac surgery: minimally invasive extracorporeal circulation vs. conventional extracorporeal circulation

Oxidative stress induced by various oxidants in a random and destructive manner is considered to play an important role in the pathophysiology in a number of disorders and diseases, as well as organ damage and complications after open heart surgery. Oxidative stress can be monitored by the qualitative and quantitative measurements of specific oxidative stress biomarkers. In this regard, advanced analytical chromatographic methods such as GC-MS, LC-MS/MS, HPTLC-MS, and various methods of spectrophotometry will be used. The choice of a suitable method for the determination of oxidative stress biomarkers depend on the chosen marker and the medium in which it is located. As biological matrix is complex, special sample preparation is needed and it is crucial for detecting OS biomarkers. Furthermore, the developed sample preparation procedure and analytical methods should be validated in order to ensure selectivity, repeatability, linearity, accuracy, precision, stability, and reproducibility. Validated analytical methods will be used to determine the oxidative stress biomarkers in real samples. The amount of oxidative stress and its association on the outcomes will be evaluated in open-heart surgery patients using two different extracorporeal bypass circuits. The study will compare oxidative stress in patients undergoing coronary artery bypass grafting with either minimally invasive extracorporeal circulation or conventional extracorporeal circulation. Extracorporeal circulation during cardiac surgery is unavoidably associated with increased inflammatory response syndrome, which significantly affects the postoperative morbidity and mortality in these patients. There is evidence that using minimally invasive extracorporeal circulation results in reduced perioperative oxidative stress. Evaluating different biomarkers of oxidative stress before, during and after cardiac surgery could allow us to create pharmacokinetic profiles of these markers and establish a baseline for future research. Furthermore, understanding the pharmacokinetics is fundamental in designing future antioxidant protocols in order to minimize the oxidative stress and consequently complications in these patients. The statistical analysis of obtained results will check the reproducibility of the data and possible statistical differences (variation of the results according to selected parameters), as well as mutual influences and correlations of the individual parameters.