AGING AND COGNITION AFTER CARDIAC SURGERY

老年患者将越来越多地接受心脏手术 老年心脏病患者的人数每年都在增加。 年龄是患者手术并发症的一个递增风险因素 接受冠状动脉旁路移植(CABG)手术的患者。老年患者 似乎尤其有更高的认知和认知能力 术后神经心理功能障碍。这一机制通过它 这种情况的发生尚不清楚。我们建议检验这个假设 年龄相关的脑自我调节功能障碍导致术后 心脏手术患者的认知和神经心理功能障碍。 将测试两种类型的大脑自动调节：压力-流量 自动调节和代谢流自动调节。这是第一次 神经心理学术后发生率的前瞻性研究 老年人的功能障碍；神经心理功能障碍的发生率 将通过300例冠脉搭桥术的神经学和心理测试来确定 患者超过三年。认知功能障碍的持续时间为 由系列测试确定。这一假设将通过以下方式进行检验： 两种不同温度下的Xe(133)间隙CBF测定(即， 脑代谢状况)和两种不同的灌流压力 在体外循环期间(即压力-流量条件)。 脑脊液(CSF)磷酸肌酸脑特异性同工酶和 术后24小时将测定腺苷酸激酶 缺血性损伤的生化标记物被认为是由受损引起的 体外循环期间的自动调节和脑血流量不足。一个 全面的神经心理测试将在 手术前一天和出院时(7-10天)、6周和6个月 冠状动脉搭桥术后。体外循环(CPB)是一种理想的体外循环模式 操纵脑代谢灌流压而不能 在其他人类实验环境中复制。此外，CPB是一种 研究神经心理功能障碍的极佳模型 可以重现相对较高的事件发生率。新知识 在这次调查中产生的可能导致实施不同的 管理原则可以显著减少 这是老年人心脏手术的主要并发症。 值得注意的是，这将是人类的第一次正直的考验 对老年人脑血流的自动调节，将提供新的 以及有关衰老生理学的重要信息。

Elderly patients will increasingly undergo cardiac surgery as the general population of elderly patients with heart disease increases each year. Age is an incremental risk factor for surgical complications in patients who have coronary artery bypass graft (CABG) surgery. Elderly patients appear to be especially at increased risk of suffering cognitive and neuropsychologic dysfunction postoperatively. The mechanism by which this occurs is not known. We propose to test the hypothesis that age-related impairment in cerebral autoregulation causes postoperative cognitive and neuropsychologic dysfunction in cardiac surgical patients. Both types of cerebral autoregulation will be tested: pressure-flow autoregulation and metabolism-flow autoregulation. This is the first prospective study of the postoperative incidence of neuropsychologic dysfunction in the elderly; the incidence of neuropsychologic dysfunction will be determined by neurologic and psychometric testing in 300 CABG patients over three years. The duration of cognitive dysfunction will be determined by serial testing. The hypothesis will be tested using Xe(133) clearance CBF determinations at two different temperatures (i.e., cerebral metabolic conditions) and two different perfusion pressures (i.e., pressure-flow conditions) during cardiopulmonary bypass. Cerebrospinal fluid (CSF) creatine phosphate brain specific isoenzyme and adenylate kinase will be measured at 24 hours after surgery as biochemical markers of ischemic damage postulated to result from impaired autoregulation and inadequate CBF during cardiopulmonary bypass. A comprehensive neuropsychological test battery will be administered on the day prior to surgery and at discharge (7 - 10 days), 6 weeks and 6 months post-CABG. Cardiopulmonary bypass (CPB) is an ideal model for manipulation of cerebral metabolism perfusion pressure and cannot be duplicated in other human experimental settings. Further, CPB is an excellent model for the study of neuropsychologic dysfunction since a relatively high incidence of events can be reproduced. The new knowledge generated in this investigation could lead to implementation of different management principles that could significantly reduce the incidence of this major complication of cardiac surgery in the elderly. Significantly, this will be the first examination in man of the integrity of cerebral blood flow autoregulation of the elderly and will provide new and important information about the physiology of aging.