[Neuropathological findings after cardiac surgery-retrospective study over 6 years]

Neuropathological studies may contribute to the discovery of central nervous system complications after heart surgery and thus help to reduce the incidence of postoperative neurological or cognitive disturbances. We examined the brains of 262 such patients operated for coronary bypass, valve replacement, or heart transplantation. Circulatory disturbances (macro- and microhemorrhages, infarcts, subarachnoid hemorrhages, and hypoxemic brain damage) were present in 128 cases (49%), as the cause of death in 33 cases (12.6%). The infarcts were caused by local arteriosclerosis of brain arteries, arterial emboli originating from the operative sites or myocardial infarctions, or by fat emboli, foreign body emboli or megakaryocytic capillary emboli in rare cases. Inflammatory disturbances were present in 17 cases and consisted of fungal or bacterial septicopyemic changes (12) or of glial nodules (5) as the substrate of a viral or autoimmunencephalitis (Bickerstaff). An incidental finding was Alzheimer's disease in 37 cases (14% of the material) of elderly patients, often associated with cerebral amyloid angiopathy but not as cause of death or cause of macroscopic brain hemorrhage. Since we have conducted an autopsy study, there is a limitation to transfer the documented changes to the total group of post-cardiac surgery patients with neurologic and cognitive deficits. Contrary to some previous reports, histologically overt microembolic phenomena do not seem to play a major role in our material. On the other hand, careful scrutiny revealed non-fatal white matter microhemorrhages of varying frequency in the different groups, especially after valve operations. These as well as the occasional glial nodules, after resorption and microscarring, could well be the cause of slight neurologic and cognitive impairments.