Neurocognitive Outcome After Coronary Artery Bypass Surgery Using Minimal Versus Conventional Extracorporeal Circulation

Despite improvements in the biocompatibility of cardiopulmonary bypass (CPB) circuits, the activation of inflammatory systemic response can result in clinically relevant organ dysfunction. Regarding the central nervous system, prolonged hypoperfusion and microembolization during conventional CPB have been related to postoperative neurologic impairment with an incidence varying from 30% to 60%. This clinical scenario covers a spectrum from a transient subtle cognitive dysfunction to a permanent stroke. Postoperative cognitive decline (POCD) is characterized as impairment in attention, cognition, recognition, orientation, memory, and learning. It may result in prolonged hospitalization, increased morbidity and mortality, while it has an adverse impact on quality of life after surgery.

Near-infrared spectroscopy (NIRS) provides a continuous and noninvasive monitoring of regional cerebral oxygen saturation (rSO2). Recent studies have shown a significant relationship between intraoperative cerebral oxygen desaturation, indicative of cerebral ischemia, and early POCD in patients undergoing elective coronary bypass grafting (CABG) with conventional extracorporeal circulation (CECC). In an attempt to reduce CPB-inherent side effects, a minimal extracorporeal circulation (MECC) system was developed and it is evaluated in clinical practice. The aim of this pilot study was to define whether there is a difference in early postoperative neurocognitive functioning between patients being operated for CABG on MECC versus CECC systems as well as whether this can be attributed to improved cerebral perfusion intraoperatively.