Cognitive impairment following cardiopulmonary bypass: strategies for its prevention
- Division of Cardiothoracic Surgery, Clinical Research Unit, Emory University School of Medicine, Atlanta, Georgia, USA
- Correspondence to Dr Michael E Halkos, Division of Cardiothoracic Surgery, Emory University School of Medicine, Emory University Hospital Midtown, 550 Peachtree Street, NE, MOT, 6th floor, Division of CTS, Atlanta, GA 30308, USA;
Contributors This is an invited editorial that was written by the authors on the manuscript.
Adverse neurological outcomes have plagued cardiac surgical procedures since the origins of the speciality. The spectrum of adverse neurological events range from clinically overt postoperative stroke to minor cognitive impairment. Despite an abundance of clinical investigations that have sought to identify and modify risk factors for these events, practice patterns have not changed drastically with regards to extracorporeal circulation and aortic manipulation, with most centres establishing protocols within the confines of their institutions and comfort level.
In their paper published in Heart, Anastasiadis and colleagues1 report results comparing patients undergoing coronary artery bypass surgery (CABG) using a minimal extracorporeal circuit (MECC) compared with a conventional circuit (CECC). The authors are to be congratulated on a well-designed randomised prospective study that adds to the growing body of literature supporting the use of MECC during cardiac operations requiring cardiopulmonary bypass (CPB). In this study, 32 patients undergoing CABG were randomly allocated to each group. Regional cerebral oxygen saturation was monitored using near-infrared spectroscopy (NIRS), and neurocognitive function was assessed preoperatively, at discharge and at 3 months postoperatively using a battery of standardised neurocognitive tests. Patient demographics and clinical characteristics were similar between the groups, with no significant difference in mortality and no major postoperative neurological events in either group. From their NIRS data, there was a significantly higher incidence of cerebral oxygen desaturation episodes (CODE) in the CECC group compared with the MECC group (55% vs 38%, p=0.04). A regional oxygen desaturation score greater than 3000, a risk marker of greater early postoperative neurocognitive decline, was more common in the CECC group compared with the MECC group (35% vs 21%, p=0.01).2 Three-month neurocognitive results showed better neurocognitive performance on most tests for the MECC group …