A randomized comparison between two different CPB oxygenators in order to improve recovery from delirium and or cognitive decline in the elderly during cardiac surgery.

Abstract

Introduction: Previous studies reported that the type of oxygenating system used in extracorporeal circulation is directly involved in incidence of post‐operative delirium and post‐operative cognitive impairment (up to 30%‐45% of elderly patients undergoing cardiac surgery) with a significant impact on quality of life, hospitalizations and short‐ and long‐term mortality. A multicenter, single blind randomized study was performed to determine if a new oxygenator, Remowell2, compared with current gold standard technologies, can reduce delirium and cognitive dysfunction in older patients undergoing cardiac surgery. Methods: We randomized 175 elderly patients (age 65+) undergoing cardiac surgery (Coronary Artery Bypass Graft) to two different cardiopulmonary bypass (CPB) oxygenators (87 Inspire and 88 Remowell2) between september 2019 and march 2022. Primary aim of the study was to assess incidence of intra hospital delirium (CAM scale evaluation) and any difference between the two groups according to structural differences between the construction technologies of the two types of CPB oxygenators; secondary endpoints were evaluation of cognitive decline after 6 months (evaluated by neuropsychiatric tests and MoCa test). We also recorded incidence of AMI in the first 72 postoperative hours, ARDS during the entire intra hospital lenght of stay and 1 year incidence of deaths, cardio‐vascular related deaths, cerebral stroke and re‐hospitalization. Results: No statstical difference were observed in baseline characteristics between the two randomized groups. A statistical trend (p=0.093) was observed in favour of the Remowell2 (16.0%) group versus Inspire (26.0%) regarding the incidence of severe postoperative delirium (defined as 4+ positive CAM or need for delirium therapy), a predictable lower performance was observed in the delirium group in executing neuropsycological test at discharge and up to 6 months with a good recovery at one year. Marginal effect plots showed differences in enolase levels (p=0.049), white blood cells (p=0.006) and neutrophils (p=0.003) in favour of Remowell2. Plasmatic levels of pro‐inflammatory markers were higher in the severe delirium group as well as the incidence of deaths (Log‐Rank test p=0.022) and cerebrovascular events (p=0.012) at one year. No statistical difference between oxygenators was detected for AMI and ARDS events during the hospital stay. Discussion: Using of novel and better construction tecnologies in CPB oxygenators devices is probably associated with a better outcome in the elderly population undergoing cardiac surgery especially regarding neurocognitive and neurological outcomes.