Evered Lisbeth A, Silbert Brendan S, Scott David A, Maruff Paul, Laughton Katrina M, Volitakis Irene, Cowie Tiffany, Cherny Robert A, Masters Colin L, Li Qiao-Xin
Centre for Anaesthesia and Cognitive Function, Department of Anaesthesia, St. Vincent's Hospital, University of Melbourne, Melbourne, Victoria, Australia.
Ann Thorac Surg. 2009 Nov;88(5):1426-32. doi: 10.1016/j.athoracsur.2009.07.003.
Decreased cognitive function associated with coronary artery bypass graft surgery is common. These deficits may be similar to the cognitive dysfunction seen in the spectrum of mild cognitive impairment to Alzheimer's disease, which are believed to result from the accumulation of amyloid beta (Abeta) peptide in the brain. We measured cognition both before and after coronary artery bypass graft surgery and assayed Abeta levels to investigate whether the cognitive dysfunction of cardiac surgery was associated with Abeta levels.
The plasma of 332 patients, who had undergone neuropsychological testing before and 3 and 12 months after coronary artery bypass graft surgery, was analyzed for Abeta(42) and Abeta(40). Patients were classified as having preexisting cognitive impairment if cognitive function was decreased in two or more tests compared with a healthy control group, and postoperative cognitive dysfunction was defined as a decline in two or more tests compared with the group mean baseline score.
Preexisting cognitive impairment was present in 117 patients (35.2%), and postoperative cognitive dysfunction was present in 40 (12%) at 3 months and 41 (13%) at 12 months after surgery. Both plasma Abeta(42) and Abeta(40) levels assessed before the surgery were significantly lower in patients who later had postoperative cognitive dysfunction at 3 months.
Decreased preoperative plasma levels of Abeta(42) and Abeta(40) in patients who exhibit postoperative cognitive dysfunction at 3 months suggest that postoperative cognitive dysfunction at this time may share a common mechanism with mild cognitive impairment and Alzheimer's disease. This process may be exacerbated by anesthesia.
冠状动脉搭桥手术相关的认知功能下降很常见。这些缺陷可能类似于在轻度认知障碍到阿尔茨海默病范围内所见的认知功能障碍，据信这是由大脑中β淀粉样蛋白（Aβ）肽的积累所致。我们在冠状动脉搭桥手术前后测量了认知功能，并检测了Aβ水平，以研究心脏手术的认知功能障碍是否与Aβ水平相关。
对332例在冠状动脉搭桥手术前以及术后3个月和12个月接受神经心理学测试的患者的血浆进行Aβ（42）和Aβ（40）分析。如果与健康对照组相比，两项或更多测试中的认知功能下降，则将患者分类为存在术前认知障碍，术后认知功能障碍定义为与组平均基线评分相比两项或更多测试中的下降。
117例患者（35.2%）存在术前认知障碍，术后3个月有40例（12%）出现术后认知功能障碍，术后12个月有41例（13%）出现。在术后3个月出现认知功能障碍的患者中，术前评估的血浆Aβ（42）和Aβ（40）水平均显著较低。
术后3个月出现认知功能障碍的患者术前血浆Aβ（42）和Aβ（40）水平降低，表明此时的术后认知功能障碍可能与轻度认知障碍和阿尔茨海默病有共同机制。麻醉可能会加剧这一过程。
