[Cerebral comlications of surgery using cardiopulmonary bypass]

The number of open heart surgery procedures using cardiopulmonary bypass increases each year. The objective of this review is to describe the frequency of cerebral complications to such open heart surgery in 18 retrospective and prospective studies published after 1980. In prospective studies the overall frequency of central nervous system complications was 5-61% and the frequency of stroke and transitory ischaemic attack (TIA) was 2-24%. A total of 1-12% suffered from prolonged encephalopathy. In retrospective studies the frequency of central nervous complications was 1-2%. At neuropsychological tests 30-79% showed significant deterioration at the seventh to ninth postoperative day. After six months 80% achieved the same test results as prior to surgery. It is difficult to compare the studies because of major differences in study design. Stroke and TIA seemed to occur more frequent in older studies, in prospective studies and in studies based on valve surgery. Most studies were uncontrolled. We conclude that the risk of central nervous system complications to open heart surgery needs to be re-evaluated in prospective studies of well-defined patients, including matched control groups and a long follow-up period.