Neuromonitoring and neurocognitive outcome in off-pump versus conventionalcoronary bypass operation

Background. Cardiopulmonary bypass seems to be a major cause for both intra operative microemboli and cerebral hypoperfusion. This study investigates h igh intensive transient signals (HITS) in transcranial Doppler ultrasound ( TCD) and serum levels of the neurobiochemical marker protein S-100 in patie nts who underwent coronary artery bypass operation without cardiopulmonary bypass (off-pump CABG) in comparison with the conventional procedure using cardiopulmonary bypass (CPB). The results are related to the neuropsycholog ic outcome in both surgical groups. Methods. Forty patients were randomized in 2 groups (20 conventional and 20 off-pump CABG). Neurocognitive status was assessed preoperatively and post operatively. Venous serum levels of S-100 protein were measured before and after coronary operation, HITS were measured in the middle cerebral artery during the operation. Results. The median value of HITS was 394.5 (0 to 2217) in the conventional versus 11 (0 to 50) in the off-pump group, p less than 0.0001. Postoperati ve S-100 serum levels were: 3.76 (0.13 to 11.2) mu g/L (conventional) versu s 0.13 (0.04 to 1.01) mu g/L (off-pump), p less than 0.0001. Postoperative cognitive testing showed significantly different results with a postoperati ve impairment of 90% of the patients in the conventional group versus no im pairment in the off-pump group. Conclusions. Cognitive impairment seems to be strongly associated to CPB an d the occurrence of microemboli. The off-pump technique appears to be promi sing in order to eliminate the source of these neuropyschologic impairments following CABG operation. (C) 2000 by The Society of Thoracic Surgeons.