Pathophysiological predictors of the short-and long-term neurobehavioral outcome of cardiac surgery with extracorporeal circulation

Abstract

Neurobehavioral sequelae of cardiac surgery under cardiopulmonary bypass conditions have gained increasing importance during the last few decades. There are several lines of arguments which demonstrate the significance of neurobehavioral alterations after heart surgery; four of them will be outlined in the following:

• ▸ Although cardiac surgery has become much safer when judged by the incidence rates of adverse neurological outcome, the figures for subtle neurobehavioral alterations remain high. Depending on the respective neuropsychological test procedures, the time of assessment, and the patient groups involved, incidence data of postoperative neuropsychological deficits range up to 80% (10) with a peak incidence of about 30%.

• ▸ Neurobehavioral disorders after cardiac surgery cause additional costs for inpatient treatment and rehabilitation. Roach and coworkers (12) estimated an additional $6,150 in-hospital boarding costs for patients with postoperative neurobehavioral disorders. This figure, however, does not include the increased spending caused by rehabilitation or early retirement due to persisting neuropsychological deficits.

• ▸ Obviously, neurobehavioral disorders have a major impact on the postoperative quality of life of patients undergoing cardiac surgery under cardiopulmonary bypass conditions. Research on variables influencing the short- and long-term neurobehavioral outcome may, therefore, help to improve the overall benefit of cardiac surgery.

• ▸ In contrast to patient groups which are usually subject of neuropsychological research, the prevailing number of patients undergoing cardiac surgery with extracorporeal circulation show no substantial preoperative brain disorders. Heart surgery under cardiopulmonary bypass conditions, therefore, represents a unique paradigm of “experimental brain research in humans” (also named as “virtual laboratory of delirium research” by Heller and Kornfeld (4)) which may provide valuable insight into the pathophysiology of neuropsychological disorders.