Preoperative and intraoperative haemodynamic risk factors for cognitive decline after cardiac surgery

Adverse cognitive outcomes are commonly observed after cardiac surgery, mostly in relation to cardiopulmonary bypass during cardiac surgery. The main aims of the present study were to investigate whether preoperative cerebral hypoperfusion was associated with postoperative cognitive decline (POCD), and whether lateralized hypoperfusion would differentially affect POCD in cardiac surgery patients. Moreover, the lateralized effects of intraoperative microembolization in POCD were also investigated. Transcranial Doppler sonography in the left and right middle cerebral arteries was used in order to detect preoperative hypoperfusion and intraoperative microembolization. A neuropsychological evaluation (i.e.,TrailMaking Test partAand B,Digit Span Test,Memorywith 10 and 30 s interference and Phonemic Fluency) in order to assess memory, attention and executive functions was performed preoperatively, at discharge and three months after surgery. Preoperative hypoperfusion in the left but not right middle cerebral artery was associated with cognitive decline after cardiac surgery. Moreover, intraoperative microembolization in the left but not right middle cerebral artery significantly correlated with early and late POCD. Taken together, the present results provide evidence for the haemodynamic mechanisms underlying POCD in cardiac surgery patients. Preoperative and intraoperative evaluation of cerebral blood flow velocity is recommended in order to detect patients at high risk for POCD and to support them with intraoperative brain monitoring.