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Ramos K, Guilliams KP, Fields ME. The Development of Neuroimaging Biomarkers for Cognitive Decline in Sickle Cell Disease. Hematol Oncol Clin North Am 2022; 36:1167-1186. [PMID: 36400537 PMCID: PMC9973749 DOI: 10.1016/j.hoc.2022.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Sickle cell disease (SCD) is complicated by neurologic complications including vasculopathy, hemorrhagic or ischemic overt stroke, silent cerebral infarcts and cognitive dysfunction. Patients with SCD, even in the absence of vasculopathy or stroke, have experience cognitive dysfunction that progresses with age. Transcranial Doppler ultrasound and structural brain MRI are currently used for primary and secondary stroke prevention, but laboratory or imaging biomarkers do not currently exist that are specific to the risk of cognitive dysfunction in patients with SCD. Recent investigations have used advanced MR sequences assessing cerebral hemodynamics, white matter microstructure and functional connectivity to better understand the pathophysiology of cognitive decline in SCD, with the long-term goal of developing neuroimaging biomarkers to be used in risk prediction algorithms and to assess the efficacy of treatment options for patients with SCD.
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Affiliation(s)
- Kristie Ramos
- Department of Pediatrics, Washington University in St. Louis, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Kristin P Guilliams
- Department of Pediatrics, Washington University in St. Louis, 660 South Euclid Avenue, St. Louis, MO 63110, USA; Department of Neurology, Washington University in St. Louis, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Melanie E Fields
- Department of Pediatrics, Washington University in St. Louis, 660 South Euclid Avenue, St. Louis, MO 63110, USA; Department of Neurology, Washington University in St. Louis, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
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Fields ME, Mirro AE, Binkley MM, Guilliams KP, Lewis JB, Fellah S, Chen Y, Hulbert ML, An H, Ford AL, Lee J. Cerebral oxygen metabolic stress is increased in children with sickle cell anemia compared to anemic controls. Am J Hematol 2022; 97:682-690. [PMID: 35113471 DOI: 10.1002/ajh.26485] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/22/2022] [Accepted: 01/29/2022] [Indexed: 01/28/2023]
Abstract
Patients with sickle cell anemia (SCA) experience cerebral metabolic stress with an increase in oxygen extraction fraction (OEF) to compensate for reduced oxygen carrying capacity due to anemia. It remains unclear if anemia alone drives this metabolic stress. Using MRI, we collected voxel-wise OEF measurements to test our hypothesis that OEF would be elevated in anemic controls without SCA (AC) compared to healthy controls (HC), but OEF would be even higher in SCA compared to AC. Brain MRIs (N = 159) were obtained in 120 participants (34 HC, 27 AC, 59 SCA). While hemoglobin was lower in AC versus HC (p < 0.001), hemoglobin was not different between AC and SCA cohorts (p = 0.459). Whole brain OEF was higher in AC compared to HC (p < 0.001), but lower compared to SCA (p = 0.001). Whole brain OEF remained significantly higher in SCA compared to HC (p = 0.001) while there was no longer a difference between AC versus HC (p = 0.935) in a multivariate model controlling for age and hemoglobin. OEF peaked within the border zone regions of the brain in both SCA and AC cohorts, but the volume of white matter with regionally elevated OEF in AC was smaller (1.8%) than SCA (58.0%). While infarcts colocalized within regions of elevated OEF, more SCA participants had infarcts than AC (p < 0.001). We conclude that children with SCA experience elevated OEF compared to AC and HC after controlling for the impact of anemia, suggesting that there are other pathophysiologic factors besides anemia contributing to cerebral metabolic stress in children with SCA.
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Affiliation(s)
- Melanie E. Fields
- Department of Pediatrics Washington University School of Medicine St. Louis Missouri USA
- Department of Neurology Washington University School of Medicine St. Louis Missouri USA
| | - Amy E. Mirro
- Department of Pediatrics Washington University School of Medicine St. Louis Missouri USA
| | - Michael M. Binkley
- Department of Neurology Washington University School of Medicine St. Louis Missouri USA
| | - Kristin P. Guilliams
- Department of Pediatrics Washington University School of Medicine St. Louis Missouri USA
- Department of Neurology Washington University School of Medicine St. Louis Missouri USA
- Mallinckrodt Institute of Radiology Washington University School of Medicine St. Louis Missouri USA
| | - Josiah B. Lewis
- Department of Neurology Washington University School of Medicine St. Louis Missouri USA
| | - Slim Fellah
- Department of Neurology Washington University School of Medicine St. Louis Missouri USA
| | - Yasheng Chen
- Department of Neurology Washington University School of Medicine St. Louis Missouri USA
| | - Monica L. Hulbert
- Department of Pediatrics Washington University School of Medicine St. Louis Missouri USA
| | - Hongyu An
- Mallinckrodt Institute of Radiology Washington University School of Medicine St. Louis Missouri USA
| | - Andria L. Ford
- Department of Neurology Washington University School of Medicine St. Louis Missouri USA
- Mallinckrodt Institute of Radiology Washington University School of Medicine St. Louis Missouri USA
| | - Jin‐Moo Lee
- Department of Neurology Washington University School of Medicine St. Louis Missouri USA
- Mallinckrodt Institute of Radiology Washington University School of Medicine St. Louis Missouri USA
- Department of Biomedical Engineering Washington University School of Medicine St. Louis Missouri USA
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Snyder BD, Simone SM, Giovannetti T, Floyd TF. Cerebral Hypoxia: Its Role in Age-Related Chronic and Acute Cognitive Dysfunction. Anesth Analg 2021; 132:1502-1513. [PMID: 33780389 PMCID: PMC8154662 DOI: 10.1213/ane.0000000000005525] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Postoperative cognitive dysfunction (POCD) has been reported with widely varying frequency but appears to be strongly associated with aging. Outside of the surgical arena, chronic and acute cerebral hypoxia may exist as a result of respiratory, cardiovascular, or anemic conditions. Hypoxia has been extensively implicated in cognitive impairment. Furthermore, disease states associated with hypoxia both accompany and progress with aging. Perioperative cerebral hypoxia is likely underdiagnosed, and its contribution to POCD is underappreciated. Herein, we discuss the various disease processes and forms in which hypoxia may contribute to POCD. Furthermore, we outline hypoxia-related mechanisms, such as hypoxia-inducible factor activation, cerebral ischemia, cerebrovascular reserve, excitotoxicity, and neuroinflammation, which may contribute to cognitive impairment and how these mechanisms interact with aging. Finally, we discuss opportunities to prevent and manage POCD related to hypoxia.
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Affiliation(s)
- Brina D. Snyder
- Department of Anesthesiology and Pain Management, UT Southwestern Medical Center, Dallas, TX
| | | | | | - Thomas F. Floyd
- Department of Anesthesiology and Pain Management, UT Southwestern Medical Center, Dallas, TX
- Department of Cardiothoracic Surgery, UT Southwestern Medical Center, Dallas, TX
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Defining a Taxonomy of Intracranial Hypertension: Is ICP More Than Just a Number? J Neurosurg Anesthesiol 2020; 32:120-131. [PMID: 31135572 DOI: 10.1097/ana.0000000000000609] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Intracranial pressure (ICP) monitoring and control is a cornerstone of neuroanesthesia and neurocritical care. However, because elevated ICP can be due to multiple pathophysiological processes, its interpretation is not straightforward. We propose a formal taxonomy of intracranial hypertension, which defines ICP elevations into 3 major pathophysiological subsets: increased cerebral blood volume, masses and edema, and hydrocephalus. (1) Increased cerebral blood volume increases ICP and arises secondary to arterial or venous hypervolemia. Arterial hypervolemia is produced by autoregulated or dysregulated vasodilation, both of which are importantly and disparately affected by systemic blood pressure. Dysregulated vasodilation tends to be worsened by arterial hypertension. In contrast, autoregulated vasodilation contributes to intracranial hypertension during decreases in cerebral perfusion pressure that occur within the normal range of cerebral autoregulation. Venous hypervolemia is produced by Starling resistor outflow obstruction, venous occlusion, and very high extracranial venous pressure. Starling resistor outflow obstruction tends to arise when cerebrospinal fluid pressure causes venous compression to thus increase tissue pressure and worsen tissue edema (and ICP elevation), producing a positive feedback ICP cycle. (2) Masses and edema are conditions that increase brain tissue volume and ICP, causing both vascular compression and decrease in cerebral perfusion pressure leading to oligemia. Brain edema is either vasogenic or cytotoxic, each with disparate causes and often linked to cerebral blood flow or blood volume abnormalities. Masses may arise from hematoma or neoplasia. (3) Hydrocephalus can also increase ICP, and is either communicating or noncommunicating. Further research is warranted to ascertain whether ICP therapy should be tailored to these physiological subsets of intracranial hypertension.
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MRI Markers of Neurodegenerative and Neurovascular Changes in Relation to Postoperative Delirium and Postoperative Cognitive Decline. Am J Geriatr Psychiatry 2017; 25:1048-1061. [PMID: 28760515 DOI: 10.1016/j.jagp.2017.06.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 06/08/2017] [Accepted: 06/20/2017] [Indexed: 12/17/2022]
Abstract
Postoperative delirium (POD) and postoperative cognitive decline (POCD) are common in elderly patients. The aim of the present review was to explore the association of neurodegenerative and neurovascular changes with the occurrence of POD and POCD. Fifteen MRI studies were identified by combining multiple search terms for POD, POCD, and brain imaging. These studies described a total of 1,422 patients and were all observational in design. Neurodegenerative changes (global and regional brain volumes) did not show a consistent association with the occurrence of POD (four studies) or POCD (two studies). In contrast, neurovascular changes (white matter hyperintensities and cerebral infarcts) were more consistently associated with the occurrence of POD (seven studies) and POCD (five studies). In conclusion, neurovascular changes appear to be consistently associated with the occurrence of POD and POCD, and may identify patients at increased risk of these conditions. Larger prospective studies are needed to study the consistency of these findings and to unravel the underlying pathophysiological mechanisms.
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van der Veen PH, Muller M, Vincken KL, Westerink J, Mali WPTM, van der Graaf Y, Geerlings MI. Hemoglobin, hematocrit, and changes in cerebral blood flow: the Second Manifestations of ARTerial disease-Magnetic Resonance study. Neurobiol Aging 2014; 36:1417-23. [PMID: 25618615 DOI: 10.1016/j.neurobiolaging.2014.12.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 12/07/2014] [Accepted: 12/15/2014] [Indexed: 11/26/2022]
Abstract
Hemoglobin and hematocrit are important determinants of blood viscosity and arterial oxygen content and may therefore influence cerebral blood flow (CBF). We examined cross-sectional and prospective associations of hemoglobin and hematocrit with CBF in 569 patients with manifest arterial disease (mean age 57 ± 10 years) with available data on magnetic resonance angiography to measure parenchymal CBF. Mean (SD) parenchymal CBF at baseline was 52.3 (9.8) mL/min/100 mL and decreased with 1.5 (11.0) mL/min/100 mL after on average 3.9 years of follow-up. Linear regression analyses showed that greater hemoglobin and hematocrit values were associated with lower baseline parenchymal CBF and more decline in parenchymal CBF over time, independent of cardiovascular risk factors, use of antiplatelet drugs, anticoagulants, or diuretics, and brain measures: adjusted mean differences (95% confidence interval [CI]) in decline in parenchymal CBF between patients in the lower and upper quartiles of hemoglobin and hematocrit were -2.48 (95% CI -3.70 to -1.25) and -3.69 (95% CI -5.45 to -1.94) mL/min/100 mL. Higher hemoglobin and hematocrit were associated with lower baseline parenchymal CBF and a greater decline in parenchymal CBF over time, possibly as a result of physiological compensating mechanisms.
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Affiliation(s)
- Pieternella H van der Veen
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands; Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Majon Muller
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands; Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - Koen L Vincken
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jan Westerink
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Willem P T M Mali
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Yolanda van der Graaf
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mirjam I Geerlings
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
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Price CC, Tanner JJ, Schmalfuss I, Garvan CW, Gearen P, Dickey D, Heilman K, McDonagh DL, Libon DJ, Leonard C, Bowers D, Monk TG. A pilot study evaluating presurgery neuroanatomical biomarkers for postoperative cognitive decline after total knee arthroplasty in older adults. Anesthesiology 2014; 120:601-13. [PMID: 24534857 DOI: 10.1097/aln.0000000000000080] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Total knee arthroplasty improves quality of life but is associated with postoperative cognitive dysfunction in older adults. This prospective longitudinal pilot study with a parallel control group tested the hypotheses that (1) nondemented adults would exhibit primary memory and executive difficulties after total knee arthroplasty, and (2) reduced preoperative hippocampus/entorhinal volume would predict postoperative memory change, whereas preoperative leukoaraiosis and lacunae volumes would predict postoperative executive dysfunction. METHODS Surgery (n = 40) and age-education-matched controls with osteoarthritis (n = 15) completed pre- and postoperative (3 weeks, 3 months, and 1 yr) memory and cognitive testing. Hypothesized brain regions of interest were measured in patients completing preoperative magnetic resonance scans (surgery, n = 31; control, n = 12). Analyses used reliable change methods to identify the frequency of cognitive change at each time point. RESULTS The incidence of postoperative memory difficulties was shown with delay test indices (i.e., story memory test: 3 weeks = 17%, 3 months = 25%, 1 yr = 9%). Postoperative executive difficulty with measures of inhibitory function (i.e., Stroop Color Word: 3 weeks = 21%, 3 months = 22%, 1 yr = 9%). Hierarchical regression analysis assessing the predictive interaction of group (surgery, control) and preoperative neuroanatomical structures on decline showed that greater preoperative volumes of leukoaraiosis/lacunae were significantly contributed to postoperative executive (inhibitory) declines. CONCLUSIONS This pilot study suggests that executive and memory declines occur in nondemented adults undergoing orthopedic surgery. Severity of preoperative cerebrovascular disease may be relevant for understanding executive decline, in particular.
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Affiliation(s)
- Catherine C Price
- From the Department of Clinical and Health Psychology, University of Florida, Gainesville, Florida (C.C.P., J.J.T., D.D., and D.B.); Joint Appointment, Department of Anesthesiology, University of Florida, Gainesville, Florida (C.C.P.); Department of Radiology, University of Florida, Gainesville, Florida (I.S.); Department of Radiology, North Florida South Georgia Veteran Association, Gainesville, Florida (I.S.); Health Science Center, University of Florida, Gainesville, Florida (C.W.G.); Department of Orthopedic Surgery, University of Florida, Gainesville, Florida (P.G. and D.B.); Department of Neurology, University of Florida, Gainesville, Florida (K.H. and T.G.M.); Department of Anesthesiology, Duke University, Durham, North Carolina (D.L.M.); Department of Neurology, Drexel University, Philadelphia, Pennsylvania (D.J.L.); and Department of Neuroscience, University of Florida, Gainesville, Florida (C.L.)
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Gottesman RF, Sojkova J, Beason-Held LL, An Y, Longo DL, Ferrucci L, Resnick SM. Patterns of regional cerebral blood flow associated with low hemoglobin in the Baltimore Longitudinal Study of Aging. J Gerontol A Biol Sci Med Sci 2012; 67:963-9. [PMID: 22552368 DOI: 10.1093/gerona/gls121] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Anemia has been associated with elevated cerebral blood flow (CBF) in animal models and certain clinical conditions (eg, renal disease), but whether hemoglobin level variations across a relatively normal range are associated with local or diffuse CBF changes is unclear. We investigated whether lower hemoglobin is associated with regional increases in relative CBF in older individuals, and if these increases occur in watershed regions. METHODS Seventy-four older nondemented adults underwent serial (15)O water positron emission tomography scans. Voxel-based analysis was used to investigate regional relative CBF patterns in association with hemoglobin level and in individuals with and without anemia. Analyses of cross-sectional relations between regional CBF and anemia were performed separately at two time points, 2 years apart, to identify replicable patterns of associations. RESULTS Restricting results to associations replicated across two cross-sectional analyses, lower hemoglobin was associated with higher relative CBF within the middle/inferior frontal, occipital, precuneus, and cerebellar regions. In addition, individuals with anemia (n = 15) showed higher relative CBF in superior frontal, middle temporal, hippocampal, and gyrus rectus regions than those without anemia. In some regions (right superior temporal gyrus, left inferior frontal gyrus, midline cuneus, and right precuneus); however, lower hemoglobin was associated with lower relative CBF. CONCLUSIONS In nondemented individuals, lower hemoglobin is associated with elevated relative CBF in specific cortical areas but reduced CBF in other areas. Whether this association between anemia and CBF in the absence of chronic diseases and in a normal physiologic range is related to clinical endpoints warrants further study.
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Affiliation(s)
- Rebecca F Gottesman
- Department of Neurology, Johns Hopkins University School of Medicine, Meyer 6-113, 600 North Wolfe Street, Baltimore, MD 21287, USA.
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Schoen J, Meyerrose J, Paarmann H, Heringlake M, Hueppe M, Berger KU. Preoperative regional cerebral oxygen saturation is a predictor of postoperative delirium in on-pump cardiac surgery patients: a prospective observational trial. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2011; 15:R218. [PMID: 21929765 PMCID: PMC3334763 DOI: 10.1186/cc10454] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 07/22/2011] [Accepted: 09/19/2011] [Indexed: 12/11/2022]
Abstract
Introduction Postoperative delirium is an important problem in patients undergoing major surgery. Cerebral oximetry is a non-invasive method to detect imbalances in the cerebral oxygen supply/demand-ratio. Low preoperative cerebral oxygen saturation (ScO2) levels have been associated with postoperative delirium in non-cardiac surgery patients. The present prospective observational study determines the relationship between pre- and intra-operative ScO2 levels and postoperative delirium in patients undergoing on-pump cardiac surgery. Methods After approval of the local ethical committee and written informed consent, N = 231 patients scheduled for elective/urgent cardiac surgery were enrolled. Delirium was assessed by the confusion-assessment-method for the intensive care unit (CAM-ICU) on the first three days after surgery. ScO2 was obtained on the day before surgery, immediately before surgery and throughout the surgical procedure. Preoperative cognitive function, demographic, surgery related, and intra- and post-operative physiological data were registered. Results Patients with delirium had lower pre- and intra-operative ScO2 readings, were older, had lower mini-mental-status-examination(MMSE) scores, higher additive EuroScore and lower preoperative haemoglobin-levels. The binary logistic regression identified older age, lower MMSE, neurological or psychiatric disease and lower preoperative ScO2 as independent predictors of postoperative delirium. Conclusions The presented study shows that a low preoperative ScO2 is associated with postoperative delirium after on-pump cardiac surgery.
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Affiliation(s)
- Julika Schoen
- Department of Anaesthesiology, University of Luebeck, Ratzeburger Allee 160, Luebeck, 23538, Germany
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Baufreton C, Pinaud F, Corbeau JJ, Chevailler A, Jolivot D, Ter Minassian A, Henrion D, de Brux JL. Increased cerebral blood flow velocities assessed by transcranial Doppler examination is associated with complement activation after cardiopulmonary bypass. Perfusion 2010; 26:91-8. [DOI: 10.1177/0267659110392439] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The role of complement activation on the cerebral vasculature after cardiopulmonary bypass (CPB) is unclear. The goal of the study was to assess whether heparin-coated CPB reduces complement activation, and influences cerebral blood flow velocities (CBFV). Twenty-four patients undergoing coronary surgery were randomly allocated to non-coated (NC-group) or heparin-coated (HC-group) CPB. Complement activation was assessed by measuring sC5b-9. Transcranial Doppler (TCD) was performed on middle cerebral arteries before and after CPB. Systolic (SV), diastolic (DV) and mean (MV) CBFV were measured. Significant increase of sC5b-9 (p=0.003) was observed in the NC-group and CBFV increased after CPB (SV by 27%, p=0.05; DV by 40%, p=0.06; MV by 33%, p=0.04) whereas no changes were detected in the HC-group. TCD values were higher in the NC-group than in the HC-group (SV, p=0.04; DV, p=0.03; MV, p=0.03) although cardiac index, systemic vascular resistance, haematocrit and pCO2 were similar. Postoperative SV, DV and MV were significantly correlated with sC5b-9 (r=0.583, p=0.009; r=0.581, p=0.009; r=0.598, p=0.007, respectively). Increased CBFV after CPB are correlated to the level of complement activation and may be controlled by heparin-coated circuits.
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Affiliation(s)
- C. Baufreton
- Department of Cardiac Surgery, University Hospital, Angers, France,
| | - F. Pinaud
- Department of Cardiac Surgery, University Hospital, Angers, France, Department of Anaesthesiology, University Hospital, Angers, France, Laboratory of Immunology University Hospital, Angers, France, UMR-CNRS 6214, INSERM 771, University of Angers, Angers, France
| | - JJ Corbeau
- Department of Anaesthesiology, University Hospital, Angers, France
| | - A. Chevailler
- Laboratory of Immunology University Hospital, Angers, France
| | - D. Jolivot
- Department of Cardiac Surgery, University Hospital, Angers, France
| | - A. Ter Minassian
- Department of Anaesthesiology, University Hospital, Angers, France
| | - D. Henrion
- UMR-CNRS 6214, INSERM 771, University of Angers, Angers, France
| | - JL de Brux
- Department of Cardiac Surgery, University Hospital, Angers, France
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Slight RD, Alston RP, McClelland DB, Mankad PS. What Factors Should We Consider in Deciding When to Transfuse Patients Undergoing Elective Cardiac Surgery? Transfus Med Rev 2009; 23:42-54. [DOI: 10.1016/j.tmrv.2008.09.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Wolf RL, Detre JA. Clinical neuroimaging using arterial spin-labeled perfusion magnetic resonance imaging. Neurotherapeutics 2007; 4:346-59. [PMID: 17599701 PMCID: PMC2031222 DOI: 10.1016/j.nurt.2007.04.005] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The two most common methods for measuring perfusion with MRI are based on dynamic susceptibility contrast (DSC) and arterial spin labeling (ASL). Although clinical experience to date is much more extensive with DSC perfusion MRI, ASL methods offer several advantages. The primary advantages are that completely noninvasive absolute cerebral blood flow (CBF) measurements are possible with relative insensitivity to permeability, and that multiple repeated measurements can be obtained to evaluate one or more interventions or to perform perfusion-based functional MRI. ASL perfusion and perfusion-based functional MRI methods have been applied in many clinical settings, including acute and chronic cerebrovascular disease, CNS neoplasms, epilepsy, aging and development, neurodegenerative disorders, and neuropsychiatric diseases. Recent technical advances have improved the sensitivity of ASL perfusion MRI, and increasing use is expected in the coming years. The present review focuses on ASL perfusion MRI and applications in clinical neuroimaging.
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Affiliation(s)
- Ronald L Wolf
- Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA.
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Brown GG, Clark C, Liu TT. Measurement of cerebral perfusion with arterial spin labeling: Part 2. Applications. J Int Neuropsychol Soc 2007; 13:526-38. [PMID: 17445302 PMCID: PMC2408863 DOI: 10.1017/s1355617707070634] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 11/15/2006] [Accepted: 11/16/2006] [Indexed: 11/05/2022]
Abstract
Arterial spin labeling (ASL) uses magnetic resonance imaging methods to measure cerebral blood flow (CBF) non-invasively. ASL CBF validly localizes brain function and may be especially useful for studies where the time frame of behavioral change is more than a few minutes, such as in longitudinal and treatment studies. ASL measures of cerebral perfusion are highly accurate in detecting lesion laterality in temporal lobe epilepsy, stenotic-occlusive disease, and brain tumors. Among lesioned patients, ASL CBF has excellent concurrent validity when correlated with CBF measured by Positron Emission Tomography or with dynamic susceptibility-weighted magnetic resonance. ASL CBF can predict tumor grading in vivo and can predict six-month response to the surgical treatment of brain tumors. ASL's capability to selectively and non-invasively tag flow in major vessels may refine the monitoring of treatment of cerebrovascular disease and brain tumors. Conclusions about the utility of ASL are limited by the small sample sizes of the studies currently in the literature and by the uncertainty caused by the effect of brain disease on transit times of the magnetic tag. As the method evolves, ASL techniques will likely become more widely used in clinical research and practice.
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Affiliation(s)
- Gregory G Brown
- Psychology Service, VA San Diego Healthcare System, San Diego, California 92161, USA.
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Floyd TF, Ratcliffe SJ, Detre JA, Woo YJ, Acker MA, Bavaria JE, Resh BF, Pochettino AA, Eckenhoff RA. Integrity of the Cerebral Blood-Flow Response to Hyperoxia After Cardiopulmonary Bypass. J Cardiothorac Vasc Anesth 2007; 21:212-7. [PMID: 17418734 DOI: 10.1053/j.jvca.2006.02.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Indexed: 12/17/2022]
Abstract
OBJECTIVE In this study, the hypothesis that cardiopulmonary bypass (CPB) alters the cerebral blood flow (CBF) vasoconstrictive response to hyperoxia was tested. DESIGN A prospective, observational study was conducted. SETTING The study was conducted at a single university hospital. PARTICIPANTS Subjects were patients who presented for cardiac surgery with CPB. INTERVENTIONS CBF was measured before and after CPB in 12 subjects while breathing 21% O(2) and 100% O(2). CBF was measured by using continuous arterial spin labeling (CASL) perfusion magnetic resonance imaging. Arterial pO(2) (mmHg), pCO(2) (mmHg), hemoglobin (Hgb), and oxygen content (CaO(2)) were also measured. MEASUREMENTS AND MAIN RESULTS Mean age of the 12 subjects was 63 +/- 16 years. Hgb decreased from 12.0 (+/-2.4) g/dL to 9.2 (+/-2.9) g/dL postoperatively (p = 0.008). CBF increased by 39%, from 37.2 (+/-10.8) mL/100 g/min to 49.2 (+/-14.3)mL/100 g/min postoperatively (p = 0.01). In response to the hyperoxic challenge CBF decreased by 8.0 (+/-7.1) mL/100 g/min (21%) preoperatively and by 9.4 (+/-6.4) mL/100 g/min (19%) postoperatively (p = 0.58). By using multiple regression, the contribution of CPB to the hyperoxic CBF response (DeltaCBF) was evaluated, while controlling for other potentially important covariates known to influence CBF, including age, baseline CBF on 21% O(2), and changes in arterial pO(2), pCO(2), and CaO(2). CPB state was not found to be a significant covariate in controlling the CBF response to hyperoxia. CONCLUSIONS CPB does not impair the CBF response to hyperoxia.
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Affiliation(s)
- Thomas F Floyd
- Department of Anesthesiology, Penn-Presbyterian Hospital, University of Pennsylvania, Philadelphia, PA 19104-4283, USA.
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Hoffman GM. Pro: near-infrared spectroscopy should be used for all cardiopulmonary bypass. J Cardiothorac Vasc Anesth 2007; 20:606-12. [PMID: 16884998 DOI: 10.1053/j.jvca.2006.05.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Indexed: 11/11/2022]
Affiliation(s)
- George M Hoffman
- Department of Anesthesiology and Pediatrics, Medical College of Wisconsin, Pediatric Anesthesiology and Critical Care Medicine, Children's Hospital of Wisconsin, Milwaukee, WI 53226, USA.
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Petersen ET, Zimine I, Ho YCL, Golay X. Non-invasive measurement of perfusion: a critical review of arterial spin labelling techniques. Br J Radiol 2006; 79:688-701. [PMID: 16861326 DOI: 10.1259/bjr/67705974] [Citation(s) in RCA: 244] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The non-invasive nature of arterial spin labelling (ASL) has opened a unique window into human brain function and perfusion physiology. High spatial and temporal resolution makes the technique very appealing not only for the diagnosis of vascular diseases, but also in basic neuroscience where the aim is to develop a more comprehensive picture of the physiological events accompanying neuronal activation. However, low signal-to-noise ratio and the complexity of flow quantification make ASL one of the more demanding disciplines within MRI. In this review, the theoretical background and main implementations of ASL are revisited. In particular, the perfusion quantification methods, including the problems and pitfalls involved, are thoroughly discussed in this article. Finally, a brief summary of applications is provided.
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Affiliation(s)
- E T Petersen
- Department of Neuroradiology, National Neuroscience Institute, Singapore
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Floyd TF, Harris F, McGarvey M, Detre JA. Recurrence of stroke after cardiac surgery: insight into pathogenesis via diffusion-weighted and continuous arterial spin labeling perfusion magnetic resonance imaging. J Cardiothorac Vasc Anesth 2006; 21:106-9. [PMID: 17289493 DOI: 10.1053/j.jvca.2005.12.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Indexed: 11/11/2022]
Affiliation(s)
- Thomas F Floyd
- Department of Anesthesiology and Critical Care, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA.
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Li M, Ratcliffe SJ, Knoll F, Wu J, Ances B, Mardini W, Floyd TF. Aging: Impact Upon Local Cerebral Oxygenation and Blood Flow With Acute Isovolemic Hemodilution. J Neurosurg Anesthesiol 2006; 18:125-31. [PMID: 16628066 DOI: 10.1097/00008506-200604000-00006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Data from the neurosurgical critical care arena demonstrate a correlation between cerebral oxygenation, survival, and cognitive function. Transfusion may increase and hemodilution decrease cerebral oxygenation. Both acute and chronic anemia have been associated with cognitive dysfunction. Aggressive blood conservation protocols have been instituted across all age groups without conclusive evidence for their impact upon outcome. Aged subjects are at the greatest risk of cognitive sequelae after major surgery associated with significant blood loss. We hypothesize that cerebral physiologic changes associated with "normal" aging may compromise cerebral oxygenation in the presence of severe anemia.Fischer 344 rats, the NIH National Institute of Aging normal aging rat model, underwent a stepwise isovolemic hemodilution protocol. Age groups (Age Grp) studied were as follows: Age Grp-A (3 months), n=14; Age Grp-B (9 to 12 months), n=14; and Age Grp-C (24 months), n=14. Brain oxygen tension (PBrO2), laser Doppler flow, and mean arterial pressure were measured. Final hemoglobin averaged 6.1+/-0.9 g/dL. PBrO2 levels decreased from a baseline of 18.1+/-4.1 to 17.5+/-6.8 mm Hg (P=0.49), and laser Doppler flow increased by 18+/-20% (P<0.0001) after hemodilution. Employing repeated measures multiple regression, Age Grp (P=0.30) was not a significant controlling covariate of PBrO2 in response to isovolemic hemodilution. PBrO2 levels were actually higher in Age Grp-C animals at all time points of the hemodilution protocol, although this was not statistically significant. Aged animals were also fully capable of mounting a robust local cerebral hyperemic response to the anemic challenge that was not separable from the response of younger animals.
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Affiliation(s)
- Min Li
- Department of Anesthesiology and Critical Care, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA
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Brondén B, Dencker M, Allers M, Plaza I, Jönsson H. Differential Distribution of Lipid Microemboli After Cardiac Surgery. Ann Thorac Surg 2006; 81:643-8. [PMID: 16427867 DOI: 10.1016/j.athoracsur.2005.08.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Revised: 07/30/2005] [Accepted: 08/15/2005] [Indexed: 01/09/2023]
Abstract
BACKGROUND Lipid microemboli found in shed blood during cardiac surgery have been shown to block capillaries of the brain postoperatively. In this study, the distribution of lipid microemboli in different regions of the brain and other organs was examined. A novel porcine model using radioactive lipid particles was used. METHODS Ten animals (2 controls and 8 cases) were anesthetized and put on cardiopulmonary bypass. A shed-blood phantom was produced from arterial blood, saline, and tritium-labeled triolein. The phantom was infused into the cardiopulmonary bypass circuit. Tissue samples were taken postmortem from examined organs and prepared for scintillation counting. Levels of radioactivity were used as a measure of the uptake of lipid microemboli. RESULTS High levels of radioactivity were found in kidney and spleen (5 to 10 times higher than in the other organs investigated). In the brain, radioactivity was found in all regions examined. The gray matter of cerebrum showed the highest level of the regions examined. CONCLUSIONS This study shows that embolization of lipids is not a phenomenon restricted to the brain, but affected all the organs examined. The high levels found in the kidneys, and the relatively high levels in the gray matter of the cerebrum further legitimize the debate on the impact lipid microemboli has on postoperative kidney and cognitive dysfunction.
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Affiliation(s)
- Björn Brondén
- Department of Cardiothoracic Anesthesiology, Center for Heart and Lung Disease, Lund University Hospital, Lund, Sweden
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Bokeriia LA, Golukhova EZ, Polunina AG, Davydov DM, Begachev AV. Neural correlates of cognitive dysfunction after cardiac surgery. ACTA ACUST UNITED AC 2005; 50:266-74. [PMID: 16198423 DOI: 10.1016/j.brainresrev.2005.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2005] [Revised: 07/29/2005] [Accepted: 08/01/2005] [Indexed: 10/25/2022]
Abstract
Patients who underwent cardiac surgery and their relatives often complain on postoperative memory impairment. Most prospective neuropsychological studies also found postoperative cognitive decline early after surgery. Nevertheless, recently several reports questioned the existence of long-term brain alterations in these patient cohorts. The present review was aimed to clear up the true cardiac surgery effects on brain and cognitive functions. The reviewed data evidence that cardiac surgery interventions induce persistent localized brain ischemic lesions along with rapidly reversing global brain swelling and decreased metabolism. A range of studies showed that left temporal region was especially prone to perioperative ischemic injury, and these findings might explain persistent verbal short-term memory decline in a considerable proportion of cardiac surgery patient cohorts. Speed/time of cognitive performance is commonly decreased early after on-pump surgery either. Nevertheless, no association between psychomotor speed slowing and intraoperative embolic load was found. The rapid recovery of the latter cognitive domain might be better explained by surgery related acute global brain metabolism changes rather than ischemic injury effects. Hence, analyses of performance on separate cognitive tests rather than summarized cognitive indexes are strongly recommended for future neuropsychological studies of cardiac surgery outcomes.
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Affiliation(s)
- Leo A Bokeriia
- A. N. Bakulev Scientific Center of Cardiovascular Surgery, Russian Academy of Medical Sciences, Moscow, Russia
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Sakurai M, Takahara Y, Takeuchi S, Mogi K. Cognitive dysfunction following cardiovascular surgery. ACTA ACUST UNITED AC 2005; 53:251-4. [PMID: 15952316 DOI: 10.1007/s11748-005-0034-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The aim of this study was the evaluation of perioperative cognitive dysfunction in patients undergoing cardiovascular surgery with or without cardiopulmonary bypass (CPB) and identification of the risk factors. SUBJECTS AND METHODS Between July 2001 and October 2003, we performed cognitive examinations in 192 patients (mean age 65.5 +/- 7.6 years) who underwent elective cardiovascular surgery with or without CPB. The cognitive examinations (Hasegawa dementia scale) were done both pre- and postoperatively. Forty-six patients who had developed cognitive dysfunction postoperatively were included in Group A. The remaining 146 patients were placed in the control group (Group B). RESULTS The patients in Group A were noted to be significantly older than those in Group B (69.8 +/- 7.4 vs. 64.1 +/- 7.2, p < 0.05). The number of patients who at risk for cerebrovascular disease was significantly higher in Group A than in Group B (p < 0.05). Among intraoperative variables, there were no significant differences between the two groups concerning the presence or absence of CPB, CPB duration, and operation duration. The length of postoperative hospitalization of the Group A patients was greater. Age was identified as the only predictor of postoperative cognitive dysfunction in multivariate analysis. CONCLUSION In the present study, it is possible that CPB did not play a significant role in the genesis of cognitive dysfunction after cardiovascular surgery. Age appears to be the only significant predictor of postoperative cognitive dysfunction.
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Affiliation(s)
- Manabu Sakurai
- Division of Cardiovascular Surgery, Funabashi Municipal Medical Center, Funabashi, Chiba, Japan
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Abstract
PURPOSE OF REVIEW This review is a survey of the recent literature investigating the etiology and the relative incidence of postoperative neurological and cognitive dysfunction after cardiac surgery. RECENT FINDINGS Several studies reviewed here have employed transcranial Doppler for detection of cerebral emboli and compared results between patients undergoing beating-heart versus conventional cardiopulmonary bypass. A transcranial Doppler device ostensibly discriminating between particulate and gaseous emboli has additionally been employed, yet despite a consistently lower incidence of cerebral emboli associated with avoidance of cardiopulmonary bypass, several groups have reported similar incidences of cognitive dysfunction across these procedures, suggesting other, potentially more important, factors. Two recent studies have focused on the hazards associated with perioperative anemia in both infants and older patients, and which can result in developmental delay or profound changes in cerebral blood flow. A further study has identified an adverse interaction with postoperative hypoxia. The use of intraortic filtration for capture and removal of particulate macroemboli has been associated with a reduction in the incidence of clinically apparent central-nervous-system injury and should be further investigated. Several other studies identify pre-existing levels of central-nervous-system impairment prior to surgery, underscoring the confounding issues introduced by the failure to include a non-surgical comparator group. SUMMARY While further evidence of cerebral embolization continues to accrue, several studies suggest that other factors may be of equal or greater importance in cognitive dysfunction. Further investigations into the role of perioperative anemia, co-incident hypoxemia and other aspects of perioperative care, e.g. hyperglycemia and postoperative hyperthermia, are warranted.
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Affiliation(s)
- John M Murkin
- University of Western Ontario, London, Ontario, Canada.
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Ishikawa J, Kario K. American Heart Association Scientific Sessions 2004: Brain and Heart. Expert Rev Cardiovasc Ther 2005; 3:11-4. [PMID: 15723571 DOI: 10.1586/14779072.3.1.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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