Brain injury during cardiac surgery results primarily from cerebral embolism and/or reduced cerebral blood flow (CBF). The latter is of particular concern for the growing number of surgical patients who are aged and/or who have cerebral vascular disease. Normally, CBF is physiologically autoregulated (or kept constant) within a range of blood pressures, allowing for stable cerebral O2 supply commensurate with metabolic demands. Cerebral autoregulation is impaired in patients who are undergoing cardiac surgery and have cerebral vascular disease or many other conditions. Such impairment could lead to brain injury because current practices of targeting low mean arterial blood pressure empirically (usually 50-70 mmHg) during cardiopulmonary bypass (CPB) may expose patients with impaired cerebral autoregulation to cerebral hypoperfusion. The hypothesis of this study is that targeting mean arterial pressure during CPB to a level above an individual's lower autoregulatory threshold reduces the risk for early neurologic complications from cardiac surgery or postoperative cognitive decline. Cerebral autoregulation will be monitored in real time by using software that continuously compares the relation between arterial blood pressure and low-frequency changes in transcranial Doppler measured cerebral blood flow velocity as well as cerebral oximetry measured with near infrared spectroscopy using methods we have validated. The primary endpoint of the study will be a composite outcome of clinical stroke, and/or new ischemic brain lesions detected with diffusion-weighted magnetic resonance (MR) imaging, and/or cognitive decline from baseline at 4 to 6 weeks after surgery. We will further assess for a relationship between blood pressure below the limits of autoregulation and delirium, an end-point associated with morbidity and mortality. Brain injury from cardiac surgery is an important source of operative mortality, prolonged hospitalization, increased healthcare expenditure, and impaired quality of life. Developing strategies to reduce the burden of this complication has wide public health implications and is within the mission of the NHLBI.

Public Health Relevance

Neurological complications from cardiac surgery are an important source of operative mortality, prolonged hospitalization, healthcare expenditure, and impaired quality of life. New strategies of care are needed to avoid rising complications for the growing number of aged patients undergoing cardiac surgery. This study will evaluate novel techniques that could be widely used to reduce brain injury that results from inadequate brain blood flow during surgery.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
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Clinical and Integrative Cardiovascular Sciences Study Section (CICS)
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Charette, Marc F
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Johns Hopkins University
Schools of Medicine
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Hori, Daijiro; Ono, Masahiro; Adachi, Hideo et al. (2016) Effect of carotid revascularization on cerebral autoregulation in combined cardiac surgery†. Eur J Cardiothorac Surg 49:281-7
Brown 4th, Charles H; Max, Laura; LaFlam, Andrew et al. (2016) The Association Between Preoperative Frailty and Postoperative Delirium After Cardiac Surgery. Anesth Analg 123:430-5
Brown 4th, Charles H; Laflam, Andrew; Max, Laura et al. (2016) The Impact of Delirium After Cardiac Surgical Procedures on Postoperative Resource Use. Ann Thorac Surg 101:1663-9
Tekes, A; Poretti, A; Scheurkogel, M M et al. (2015) Apparent diffusion coefficient scalars correlate with near-infrared spectroscopy markers of cerebrovascular autoregulation in neonates cooled for perinatal hypoxic-ischemic injury. AJNR Am J Neuroradiol 36:188-93
Hori, Daijiro; Ono, Masahiro; Rappold, Thomas E et al. (2015) Hypotension After Cardiac Operations Based on Autoregulation Monitoring Leads to Brain Cellular Injury. Ann Thorac Surg 100:487-93
Brown 4th, Charles H; Morrissey, Candice; Ono, Masahiro et al. (2015) Impaired olfaction and risk of delirium or cognitive decline after cardiac surgery. J Am Geriatr Soc 63:16-23
Hori, Daijiro; Everett, Allen D; Lee, Jennifer K et al. (2015) Rewarming Rate During Cardiopulmonary Bypass Is Associated With Release of Glial Fibrillary Acidic Protein. Ann Thorac Surg 100:1353-8
Laflam, Andrew; Joshi, Brijen; Brady, Kenneth et al. (2015) Shoulder surgery in the beach chair position is associated with diminished cerebral autoregulation but no differences in postoperative cognition or brain injury biomarker levels compared with supine positioning: the anesthesia patient safety foundation be Anesth Analg 120:176-85
Hori, Daijiro; Hogue Jr, Charles W; Shah, Ashish et al. (2015) Cerebral Autoregulation Monitoring with Ultrasound-Tagged Near-Infrared Spectroscopy in Cardiac Surgery Patients. Anesth Analg 121:1187-93
Maxwell, Bryan G; Hogue Jr, Charles W; Pronovost, Peter J (2015) Does it matter who the anesthesiologist is for my heart surgery? Anesth Analg 120:499-501

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