Early and late predictors of postoperative neurocognitive dysfunction in cardiac surgery

Postoperative cognitive dysfunction (POCD) is a multifactorial image characterized by insufficiency in features such as the ability to perform tasks requiring high brain functions. Cognitive dysfunction such as memory loss and decreased concentration, confusion, and delirium are common conditions in some patients in the early period after major surgical interventions such as cardiac surgery. POCD causes delays in postoperative recovery, long return-to-work times, and decreased quality of life. This study aims to demonstrate POCD in early and late stages in patients undergoing cardiac surgery through the Montreal Cognitive Assessment (MoCA) and the Mini Mental Test (MMT). In addition, we aim to determine predictive factors with these neurocognitive tests.

MMT and MoCA tests were applied to the patients included in the study before cardiac surgery, on the sixth postoperative day and third month. Neuro-cognitive dysfunction detected on the sixth postoperative day was accepted as an early period, its detection in the postoperative third month was accepted as a late period.

127 patients without neurocognitive dysfunction in the preoperative period were included in the study. For early neurocognitive impairment, age, mean platelet volume (MPV), New York Heart Association (NYHA) classification, x-clamp time, cardio-pulmonary bypass (CPB) time, postoperative intensive care and hospital stay duration, and an event of acute myocardial infarction (AMI) in the preoperative period were determined as predictive factors. In addition, in late-period of neurocognitive dysfunction age, MPV, NYHA classification, x-clamp duration, CPB time, postoperative intensive care and hospital stay duration were shown as predictors of neurocognitive dysfunction.

The results of our study support the literature findings showing that delirium is associated with a decline in cognitive functions three months after cardiac surgery. As a result, the lack of agreed diagnostic tests in the definition of POCD makes it difficult to standardize and interpret the research in this area. Therefore, a consensus to be reached in the diagnosis of POCD will ensure the use and correct interpretation of neurophysiological tests. In our study, advanced age and long hospital and intensive care stays were shown as predictive factors for both early and late neurocognitive dysfunctions. Furthermore, smoking was shown as a predictive factor only for late neurocognitive dysfunction.