Neuropathology of mitral valve prolapse in man and cardiopulmonary bypass (CPB) surgery in adolescent Yorkshire pigs

We investigated the brains of non-demented individuals with mitral valve pr olapse (MVP) and found evidence of Alzheimer-like lesions. This neuropathol ogy consisted of premature presence of beta-amyloid-containing senile plaqu es (SP) without increased prevalence of neurofibrillary tangles. Low levels of SP occurred in 20 to 45- year-old subjects with MVP, and much greater d ensities were observed in subjects between 45 and 62 years of age. We also investigated the brains of adolescent Yorkshire pigs undergoing cardiopulmo nary bypass surgery and likewise found evidence of Alzheimer-like neuropath ology. This took the form of intraneuronal accumulation of beta-amyloid imm unoreactivity and increasing numbers of Alz-50 immunoreactive neurons with reduced recovery of cardiac efficiency after the surgery. Based on prevaili ng concepts in Alzheimer's disease, it is feasible to hypothesize that cogn itive dysfunction occurring after cardiopulmonary bypass surgery with coron ary artery grafting or valve repair/replacement is a functional sequela of AD-like neuropathology. This postulate is based on the premise that an indi vidual seeking such surgery would have pre-existing, elevated AD-like neuro pathology to start with. It is further coupled with the probability that th ese forms of cardiovascular surgery exacerbate the extent and progression o f AD-like neuropathology. (C) 2000 Elsevier Science Inc. All rights reserve d.