Cerebral outcome after extracorporeal circulation. Comparison between prospective and retrospective evaluations.

The cerebral outcome of 100 consecutive patients who had cardiac valvular replacement was evaluated by comparing the results of prospective neurological examination with retrospective data. The latter showed that the overall prevalence of cerebral abnormalities was 6% (4% among survivors) up to ten days postoperatively and 9% thereafter. This contrasts with the 35% (37% among survivors) obtained by careful neurological investigations that showed five patients with residual signs one year after operation. Electroencephalographic and neuropsychological studies disclosed additional patients who had subclinical involvement. The results question the reportedly ever-falling cerebral complication values claimed particularly in retrospective studies and reflect what is missed when using rough clinical criteria. There is no justification in overlooking slight clinical or even subclinical dysfunction, since the elimination of them is the only acceptable criterion of cerebral safety in cardiac operations.