Preliminary evidence for reduced preoperative cerebral blood flow velocity as a risk factor for cognitive decline three months after cardiac surgery: an extension study

This extension study investigated the association between preoperative cerebral blood flow (CBF) velocity and postoperative cognitive decline (POCD) at a three-month follow-up in patients who underwent cardiac surgery. Continuous transcranial Doppler ultrasound on both middle cerebral arteries (MCAs) was used preoperatively in 31 right-handed cardiac surgery patients at rest. Each patient performed a neuropsychological evaluation to assess cognitive performance before surgery, at discharge and at three-month follow-up. Patients with POCD at the three-month follow-up had a marginally significantly lower preoperative CBF velocity in the left MCA than patients without POCD. Moreover, the group with POCD had a significantly lower CBF velocity in the left than in the right MCA, whereas no difference between the left and right CBF velocity was found in the group without POCD. These preliminary findings suggest that reduced preoperative CBF velocity in the left MCA may represent an independent risk factor for cognitive decline in patients three months after surgery.