The role of asymmetry and the nature of microembolization in cognitive decline after heart valve surgery: a pilot study.

Our objective was to determine the role of asymmetry and the nature of microembolization on postoperative cognitive decline in patients who had undergone heart valve surgery. Continuous transcranial Doppler ultrasound was intraoperatively used for both middle cerebral arteries in 13 right-handed heart valve surgery patients to detect microembolization. The Trail Making Test A and B, Memory with 10/30 s interference, the Digit Span Test and Phonemic Fluency were performed preoperatively, at discharge and three months after surgery. Our data suggest that early and late postoperative psychomotor and executive functions may be sensitive to microemboli in the left, but not in the right middle cerebral artery. Moreover, solid and gaseous microemboli are both similarly associated with early postoperative cognitive decline while, surprisingly, late postoperative cognitive decline is more likely to be associated with gaseous than solid microemboli.