Cortical Beta-amyloid Levels and Neurocognitive Performance After Cardiac Surgery

描述（由申请人提供）：每年接受心脏手术的老年患者中，手术后认知功能障碍经常发生。术后认知功能障碍（POCD）在术后早期阶段存在于36-50%的患者中，并已被证明对术后一年的生活质量产生不利影响。我们的多学科神经结局研究小组的目标是了解心脏手术后神经和神经认知功能障碍的潜在机制，并减少这些破坏性结局的发生率。尽管在技术、药理学和围手术期器官保护方面取得了实质性进展，导致与心脏手术相关的死亡率降低，但POCD的发病率在过去十年中几乎没有变化。虽然已经提出了这种神经损伤的多种病因学因素，包括脑栓塞过程和灌注不足，但脑淀粉样蛋白负荷的作用从未被研究过。由于心脏手术通常发生在老年人中，因此在手术患者中观察到的认知功能障碍可能是轻度认知障碍（MCI）的一种形式，这是一种以淀粉样蛋白β-纤维积累为特征的病症。因此，我们的研究的主要目的是使用正电子发射断层扫描（PET）和一种新的PET示踪剂，具有高亲和力的b-淀粉样蛋白纤维，以确定b-淀粉样蛋白沉积和POCD之间的关系。其次，我们将评估POCD患者淀粉样蛋白沉积的区域模式，并将这些模式与先前成像的40名MCI受试者和40名老年对照组进行比较。对患者或患者家属来说，没有什么比成功的手术更具有破坏性了，手术挽救了生命，但由于认知障碍而复杂化，导致生活质量下降和功能独立性丧失。我们的研究结果将是非常宝贵的POCD的预防，我们将使用功能成像标记物，揭示最早的神经元变化，从而产生新的机制的见解，以确定区域淀粉样蛋白负荷在POCD中的作用。

DESCRIPTION (provided by applicant): Cognitive impairment after surgery occurs frequently in the large number of increasingly elderly patients undergoing cardiac surgery every year. Postoperative cognitive deficit (POCD) is present in 36-50% of patients in the early phases after surgery and has been shown to adversely impact quality of life as much as one year after surgery. The objective of our multidisciplinary Neurological Outcome Research Group is to understand the mechanisms underlying neurologic and neurocognitive dysfunction after cardiac surgery and to reduce the incidence of these devastating outcomes. Despite substantial advancement in technology, pharmacology, and perioperative organ protection leading to reductions in mortality associated with cardiac surgery, the incidence of POCD has changed little over the last ten years. While multiple etiologic factors have been proposed for this neurological injury including cerebral embolic processes and hypoperfusion, the role of brain amyloid burden has never been examined. Because cardiac surgery generally takes place in the aged, it is possible that the cognitive dysfunction seen in surgical patients is a form of mild cognitive impairment (MCI), a condition characterized by accumulation of amyloid beta-fibrils. Thus the primary aim of our study is to determine the relationship between b-amyloid deposition and POCD using positron emission tomography (PET) and a newer PET tracer with a high affinity for b-amyloid fibrils. Secondarily, we will assess regional patterns of amyloid deposition in patients with POCD and compare these patterns with a previously imaged group of 40 MCI subjects and 40 elderly controls. Little is more devastating to a patient or the patient's family than to have a successful operation that prolongs life, but is complicated by cognitive impairment resulting in a diminished quality of life and loss of functional independence. The results of our study will be invaluable to the prevention of POCD in that we will define the role of regional amyloid burden in POCD using functional imaging markers that reveal the earliest neuronal changes and thus generate new mechanistic insights.