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Hutchinson PJ, Kolias AG, Timofeev I, Corteen E, Czosnyka M, Menon DK, Pickard JD, Kirkpatrick PJ. Update on the RESCUEicp decompressive craniectomy trial. Crit Care 2011. [PMCID: PMC3066986 DOI: 10.1186/cc9732] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Timofeev I, Carpenter KLH, Nortje J, Al-Rawi PG, O'Connell MT, Czosnyka M, Smielewski P, Pickard JD, Menon DK, Kirkpatrick PJ, Gupta AK, Hutchinson PJ. Cerebral extracellular chemistry and outcome following traumatic brain injury: a microdialysis study of 223 patients. Brain 2011; 134:484-94. [PMID: 21247930 DOI: 10.1093/brain/awq353] [Citation(s) in RCA: 244] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Secondary insults can adversely influence outcome following severe traumatic brain injury. Monitoring of cerebral extracellular chemistry with microdialysis has the potential for early detection of metabolic derangements associated with such events. The objective of this study was to determine the relationship between the fundamental biochemical markers and neurological outcome in a large cohort of patients with traumatic brain injury. Prospectively collected observational neuromonitoring data from 223 patients were analysed. Monitoring modalities included digitally recorded intracranial pressure, cerebral perfusion pressure, cerebrovascular pressure reactivity index and microdialysis markers glucose, lactate, pyruvate, glutamate, glycerol and the lactate/pyruvate ratio. Outcome was assessed using the Glasgow Outcome Scale at 6 months post-injury. Patient-averaged values of parameters were used in statistical analysis, which included univariate non-parametric methods and multivariate logistic regression. Monitoring with microdialysis commenced on median (interquartile range) Day 1 (1-2) from injury and median (interquartile range) duration of monitoring was 4 (2-7) days. Averaged over the total monitoring period levels of glutamate (P = 0.048), lactate/pyruvate ratio (P = 0.044), intracranial pressure (P = 0.006) and cerebrovascular pressure reactivity index (P = 0.01) were significantly higher in patients who died. During the initial 72 h of monitoring, median glycerol levels were also higher in the mortality group (P = 0.014) and median lactate/pyruvate ratio (P = 0.026) and lactate (P = 0.033) levels were significantly lower in patients with favourable outcome. In a multivariate logistic regression model (P < 0.0001), which employed data averaged over the whole monitoring period, significant independent positive predictors of mortality were glucose (P = 0.024), lactate/pyruvate ratio (P = 0.016), intracranial pressure (P = 0.029), cerebrovascular pressure reactivity index (P = 0.036) and age (P = 0.003), while pyruvate was a significant independent negative predictor of mortality (P = 0.004). The results of this study suggest that extracellular metabolic markers are independently associated with outcome following traumatic brain injury. Whether treatment-related improvement in biochemistry translates into better outcome remains to be established.
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Patel HC, Teo M, Higgins N, Kirkpatrick PJ. High flow extra-cranial to intra-cranial bypass for complex internal carotid aneurysms. Br J Neurosurg 2010; 24:173-8. [PMID: 20128634 DOI: 10.3109/02688690903531075] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cerebral revascularisation with extracranial - intracranial (EC-IC) bypass is generally indicated in patients with complex anterior circulation aneurysms who have failed parent artery occlusion. We report on the process and outcome of our early experience of performing high flow bypass in patients with complex anterior circulation aneurysms. We have reviewed patients who have undergone an EC-IC bypass for treatment of complex anterior circulation aneurysms, and report our outcome on graft patency, surgical complications, discharge destination, and obliteration rates. Nine patients that underwent 11 bypasses are described. Seven patients had a giant saccular aneurysm of the carotid, and these were all obliterated on post-operative imaging. Two patients presenting with an intracranial carotid dissection required trapping of the diseased segment following the bypass. The overall graft patency rate was 88%. One patient developed a post operative subdural collection (managed conservatively), and one patient required early graft revision. Discharge destination was home in 8/9 patients. There was no mortality. Although EC-IC bypass is a technically challenging procedure, it provides a valuable treatment option for patients with complex anterior circulation aneurysms. Good graft patency rates can be achieved with low surgical morbidity in patients with a disease process that otherwise attracts a highly unfavourable natural history.
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Har Keong MRCS NC, Bulters DO, Richards H, Farrington M, Sparrow O, Hutchinson PJ, Pickard JD, Kirkpatrick PJ. The SILVER Trial. Neurosurgery 2010. [DOI: 10.1227/01.neu.0000387012.91823.8b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Zweifel C, Castellani G, Czosnyka M, Carrera E, Brady KM, Kirkpatrick PJ, Pickard JD, Smielewski P. Continuous assessment of cerebral autoregulation with near-infrared spectroscopy in adults after subarachnoid hemorrhage. Stroke 2010; 41:1963-8. [PMID: 20651272 DOI: 10.1161/strokeaha.109.577320] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE In patients with subarachnoid hemorrhage, the assessment of cerebral autoregulation aids in prognosis as well as detection of vasospasm. Mx is a validated index of cerebral autoregulation based on measures of cerebral perfusion pressure and mean flow velocity on transcranial Doppler but is impractical for longer-term monitoring. Near-infrared spectroscopy is noninvasive and suitable for continuous monitoring of cerebral tissue oxygenation using the Tissue Oxygenation Index. In this study, we compared near-infrared spectroscopy-based indices of cerebral autoregulation (TOx) with Mx in patients with subarachnoid hemorrhage. METHODS Arterial blood pressure, intracranial pressure, mean flow velocity, and Tissue Oxygenation Index were recorded. Mx and TOx were calculated as moving correlation coefficients between 10-second averaged values of cerebral perfusion pressure and mean flow velocity and between cerebral perfusion pressure and Tissue Oxygenation Index. We also calculated TOxA, the moving correlation coefficient between arterial blood pressure and Tissue Oxygenation Index. RESULTS Fifty-one recording sessions were performed in 27 patients with subarachnoid hemorrhage with a total duration of 62.5 hours. Correlations of Mx and TOx over time varied markedly among individual recordings. However, time-averaging over the entire recording interval in each of the 51 recordings, we found correlations between Mx and TOx and between Mx and TOxA were highly significant. This correlation was even stronger after correction for multiple sampling for each patient, reaching r=0.81 for Mx and TOx and r=0.72 for Mx and TOxA. CONCLUSIONS Near-infrared spectroscopy can be used to continuously assess cerebral autoregulation in adults after subarachnoid hemorrhage.
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Tseng MY, Hutchinson PJ, Kirkpatrick PJ. Interaction of neurovascular protection of erythropoietin with age, sepsis, and statin therapy following aneurysmal subarachnoid hemorrhage. J Neurosurg 2010; 112:1235-9. [DOI: 10.3171/2009.10.jns09954] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
In a previous randomized controlled trial, the authors demonstrated that acute erythropoietin (EPO) therapy reduced severe vasospasm and delayed ischemic deficits (DIDs) following aneurysmal subarachnoid hemorrhage. In this study, the authors aimed to investigate the potential interaction of neurovascular protection by EPO with age, sepsis, and concurrent statin therapy.
Methods
The clinical events of 80 adults older than 18 years and with < 72 hours of aneurysmal subarachnoid hemorrhage, who were randomized to receive 30,000 U of intravenous EPO-β or placebo every 48 hours for a total of 3 doses, were analyzed by stratification according to age (< or ≥ 60 years), sepsis, or concomitant statin therapy. End points in the trial included cerebral vasospasm and impaired autoregulation on transcranial Doppler ultrasonography, DIDs, and unfavorable outcome at discharge and at 6 months measured with the modified Rankin Scale and Glasgow Outcome Scale. Analyses were performed using the t-test and/or ANOVA for repeated measurements.
Results
Younger patients (< 60 years old) or those without sepsis obtained benefits from EPO by a reduction in vasospasm, impaired autoregulation, and unfavorable outcome at discharge. Compared with nonseptic patients taking EPO, those with sepsis taking EPO had a lower absolute reticulocyte count (nonsepsis vs sepsis, 143.5 vs. 105.8 × 109/L on Day 6; p = 0.01), suggesting sepsis impaired both hematopoiesis and neurovascular protection by EPO. In the EPO group, none of the statin users suffered DIDs (p = 0.078), implying statins may potentiate neuroprotection by EPO.
Conclusions
Erythropoietin-related neurovascular protection appears to be attenuated by old age and sepsis and enhanced by statins, an important finding for designing Phase III trials.
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Santarius T, Qureshi HU, Sivakumaran R, Kirkpatrick PJ, Kirollos RW, Hutchinson PJ. The Role of External Drains and Peritoneal Conduits in the Treatment of Recurrent Chronic Subdural Hematoma. World Neurosurg 2010; 73:747-50. [DOI: 10.1016/j.wneu.2010.03.031] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Accepted: 03/19/2010] [Indexed: 12/15/2022]
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Young VE, Patterson AJ, Sadat U, Bowden DJ, Graves MJ, Tang TY, Priest AN, Skepper JN, Kirkpatrick PJ, Gillard JH. Diffusion-weighted magnetic resonance imaging for the detection of lipid-rich necrotic core in carotid atheroma in vivo. Neuroradiology 2010; 52:929-36. [PMID: 20358366 DOI: 10.1007/s00234-010-0680-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Accepted: 03/05/2010] [Indexed: 12/31/2022]
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59
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Patel HC, Mcnamara IR, Al-Rawi PG, Kirkpatrick PJ. Improved cerebrovascular reactivity following low flow EC/IC bypass in patients with occlusive carotid disease. Br J Neurosurg 2010; 24:179-84. [DOI: 10.3109/02688690903536603] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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60
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Santarius T, Kirkpatrick PJ, Kolias AG, Hutchinson PJ. Working toward rational and evidence-based treatment of chronic subdural hematoma. CLINICAL NEUROSURGERY 2010; 57:112-122. [PMID: 21280503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Chronic subdural hematoma (CSDH) is one of the most common neurosurgical conditions that can usually be treated with relatively simple and effective surgical procedures. It affects primarily the elderly, a rising population worldwide. Together with improved awareness among the medical profession and greater access to modern imaging facilities, the incidence of CSDH is set to rise significantly. Maximization of the efficiency of management of CSDH is therefore a priority. To this end, a review of the findings of clinical and laboratory research underpinning the basis of the modern management of CSDH has been carried out. This review focuses on the pathophysiology and briefly discusses the epidemiology, clinical presentation, and surgical treatments of CSDH, concluding that a one-for-all management strategy is not appropriate. Creating rational bases for the selection of an ideal treatment strategy for an individual patient should be the target. This can be achieved through better understanding of the nature of the condition through systematic basic science research, ascertaining the merits of different surgical techniques in well-designed and rigorously executed clinical trials, using advances in imaging techniques to classify CSDH (a subject not addressed here), and training in and ongoing refinement of clinical acumen and surgical skills of individual surgeons.
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Al-Rawi PG, Tseng MY, Richards HK, Nortje J, Timofeev I, Matta BF, Hutchinson PJ, Kirkpatrick PJ. Hypertonic saline in patients with poor-grade subarachnoid hemorrhage improves cerebral blood flow, brain tissue oxygen, and pH. Stroke 2009; 41:122-8. [PMID: 19910550 DOI: 10.1161/strokeaha.109.560698] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND PURPOSE Delayed cerebral ischemia and infarction due to reduced CBF remains the leading cause of poor outcome after aneurysmal subarachnoid hemorrhage. Hypertonic saline (HS) is associated with an increase in CBF. This study explores whether CBF enhancement with HS in patients with poor-grade subarachnoid hemorrhage is associated with improved cerebral tissue oxygenation. METHODS Continuous monitoring of arterial blood pressure, intracranial pressure, cerebral perfusion pressure, brain tissue oxygen, carbon dioxide, pH, and middle cerebral artery flow velocity was performed in 44 patients. Patients were given an infusion (2 mL/kg) of 23.5% HS. In 16 patients, xenon CT scanning was also performed. CBF in a region surrounding the tissue oxygen sensor was calculated. Data are mean+/-SD. RESULTS Thirty minutes postinfusion, a significant increase in arterial blood pressure, cerebral perfusion pressure, flow velocity, brain tissue pH, and brain tissue oxygen was seen together with a decrease in intracranial pressure (P<0.05). Intracranial pressure remained reduced for >300 minutes and flow velocity elevated for >240 minutes. A significant increase in brain tissue oxygen persisted for 240 minutes. Average baseline regional CBF was 33.9+/-13.5 mL/100 g/min, rising by 20.3%+/-37.4% (P<0.05) after HS. Patients with favorable outcome responded better to HS in terms of increased CBF, brain tissue oxygen, and pH and reduced intracranial pressure compared with those with an unfavorable outcome. A sustained increase in brain tissue oxygen (beyond 210 minutes) was associated with favorable outcome (P<0.023). CONCLUSIONS HS augments CBF in patients with poor-grade subarachnoid hemorrhage and significantly improves cerebral oxygenation for 4 hours postinfusion. Favorable outcome is associated with an improvement in brain tissue oxygen beyond 210 minutes.
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Santarius T, Kirkpatrick PJ, Ganesan D, Chia HL, Jalloh I, Smielewski P, Richards HK, Marcus H, Parker RA, Price SJ, Kirollos RW, Pickard JD, Hutchinson PJ. Use of drains versus no drains after burr-hole evacuation of chronic subdural haematoma: a randomised controlled trial. Lancet 2009; 374:1067-73. [PMID: 19782872 DOI: 10.1016/s0140-6736(09)61115-6] [Citation(s) in RCA: 434] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Chronic subdural haematoma causes serious morbidity and mortality. It recurs after surgical evacuation in 5-30% of patients. Drains might reduce recurrence but are not used routinely. Our aim was to investigate the effect of drains on recurrence rates and clinical outcomes. METHODS We did a randomised controlled trial at one UK centre between November, 2004, and November, 2007. 269 patients aged 18 years and older with a chronic subdural haematoma for burr-hole drainage were assessed for eligibility. 108 were randomly assigned by block randomisation to receive a drain inserted into the subdural space and 107 to no drain after evacuation. The primary endpoint was recurrence needing redrainage. The trial was stopped early because of a significant benefit in reduction of recurrence. Analyses were done on an intention-to-treat basis. This study is registered with the International Standard Randomised Controlled Trial Register (ISRCTN 97314294). FINDINGS Recurrence occurred in ten of 108 (9.3%) people with a drain, and 26 of 107 (24%) without (p=0.003; 95% CI 0.14-0.70). At 6 months mortality was nine of 105 (8.6%) and 19 of 105 (18.1%), respectively (p=0.042; 95% CI 0.1-0.99). Medical and surgical complications were much the same between the study groups. INTERPRETATION Use of a drain after burr-hole drainage of chronic subdural haematoma is safe and associated with reduced recurrence and mortality at 6 months. FUNDING Academy of Medical Sciences, Health Foundation, and NIHR Biomedical Research Centre (Neurosciences Theme).
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Trivedi RA, Weerakkody RA, Turner C, Kirkpatrick PJ. Carotid artery stenosis—an evidence-based review of surgical and non-surgical treatments. Br J Neurosurg 2009; 23:387-92. [DOI: 10.1080/02688690902814741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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64
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Marcus HJ, Patel HC, Kirkpatrick PJ. Graft aneurysm complicating an extracranial-intracranial bypass. Br J Neurosurg 2009; 23:548-50. [PMID: 19718553 DOI: 10.1080/02688690902919151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
We report a patient that developed an aneurysm on a grafted saphenous vein following an extracranial-intracranial (EC-IC) bypass. Although saphenous vein graft aneurysms (SVGAs) have been described as a rare complication following coronary surgery, we are unaware of any previously reported cases of SVGAs following EC-IC bypass.
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Zweifel C, Czosnyka M, Lavinio A, Castellani G, Kim DJ, Carrera E, Pickard JD, Kirkpatrick PJ, Smielewski P. A comparison study of cerebral autoregulation assessed with transcranial Doppler and cortical laser Doppler flowmetry. Neurol Res 2009; 32:425-8. [PMID: 19703359 DOI: 10.1179/174313209x459165] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES We compared autoregulation monitored with cortical laser Doppler flowmetry (LDF) and autoregulation monitored with transcranial Doppler (TCD) in the middle cerebral artery (MCA) to verify the hypothesis that, following brain trauma, cortical vessel autoregulation to intracranial hypertension is different than assessed in the MCA. METHODS Data collected from 29 head injured patients were analysed retrospectively. Arterial blood pressure (ABP), intracranial pressure (ICP), flow velocity (FV) of the MCA and cortical flux (LDF) were monitored. Indices of cortical autoregulation (Lx) and autoregulation of cerebral blood flow in the MCA (Mx) were calculated as a moving correlation coefficient between slow waves of LDF and cerebral perfusion pressure (CPP) (Lx) or FV and CPP (Mx), respectively. Intact autoregulation was indicated by negative values for Lx and Mx; disturbed autoregulation was reflected by positive values. RESULTS FV and LDF showed a high coherence in the slow wave spectrum of 1-4 cycles/min (mean: 0.79 +/- 0.12), indicating that similar information regarding autoregulation is carried by both signals. Mx and Lx correlated in all patients (R=0.43, p=0.02). On average, Lx was significantly higher than Mx; the mean difference was 0.13 +/- 0.38 (p=0.032), potentially due to severe intracranial hypertension above 40 mmHg, driving CPP values below 60 mmHg. CONCLUSION After traumatic brain injury, cortical autoregulation appears to be worse than autoregulation assessed in the MCA during rising ICP and falling CPP. When CPP is above 60 mmHg, cortical assessed autoregulation is similar to autoregulation assessed in the MCA.
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Gallagher CN, Carpenter KLH, Grice P, Howe DJ, Mason A, Timofeev I, Menon DK, Kirkpatrick PJ, Pickard JD, Sutherland GR, Hutchinson PJ. The human brain utilizes lactate via the tricarboxylic acid cycle: a 13C-labelled microdialysis and high-resolution nuclear magnetic resonance study. ACTA ACUST UNITED AC 2009; 132:2839-49. [PMID: 19700417 DOI: 10.1093/brain/awp202] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Energy metabolism in the human brain is not fully understood. Classically, glucose is regarded as the major energy substrate. However, lactate (conventionally a product of anaerobic metabolism) has been proposed to act as an energy source, yet whether this occurs in man is not known. Here we show that the human brain can indeed utilize lactate as an energy source via the tricarboxylic acid cycle. We used a novel combination of (13)C-labelled cerebral microdialysis both to deliver (13)C substrates into the brain and recover (13)C metabolites from the brain, and high-resolution (13)C nuclear magnetic resonance. Microdialysis catheters were placed in the vicinity of focal lesions and in relatively less injured regions of brain, in patients with traumatic brain injury. Infusion with 2-(13)C-acetate or 3-(13)C-lactate produced (13)C signals for glutamine C4, C3 and C2, indicating tricarboxylic acid cycle operation followed by conversion of glutamate to glutamine. This is the first direct demonstration of brain utilization of lactate as an energy source in humans.
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Santarius T, Kirkpatrick PJ, Ganesan D, Chia HL, Jalloh I, Marcus H, Smielewski P, Price SJ, Kirollos RW, Hutchinson PJ. Randomized Controlled Trial of the Use of Drains Versus No Drains after Burr Hole Evacuation of Chronic Subdural Hematoma. Neurosurgery 2009. [DOI: 10.1227/01.neu.0000358671.05488.a2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Helmy A, Carpenter KLH, Skepper JN, Kirkpatrick PJ, Pickard JD, Hutchinson PJ. Microdialysis of cytokines: methodological considerations, scanning electron microscopy, and determination of relative recovery. J Neurotrauma 2009; 26:549-61. [PMID: 19196175 DOI: 10.1089/neu.2008.0719] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cerebral microdialysis is a monitoring technique with expanding clinical and research utility following traumatic brain injury. This study's aim was to determine the relative recovery for 12 cytokines using both crystalloid (CNS perfusion fluid) and colloid (CNS perfusion fluid supplemented with 3.5% human serum albumin) perfusate. Six CMA71 microdialysis catheters (nominal molecular weight cut-off 100 kDa) were perfused in vitro with either crystalloid or colloid and the relative recovery (%) determined for the cytokines as follows (crystalloid/colloid perfusate): IL-1alpha (50.6/48), IL-1beta (34.6/38.4), IL-1ra (21.9/38.4), IL-2 (17.1/52.8), IL-4 (26/56.7), IL-6 (9.8/25.5), IL-8 (47.7/73.4), IL-10 (2.9/8.7), IL-17 (14.4/43.7), TNF-alpha (4.4/31.2), MIP-1alpha (31.8/55.6), and MIP-1beta (31.9/50.1). The colloid perfusate significantly improved relative recovery for nine of these cytokines ( p < 0.05), but not for IL-1alpha, IL-1beta, and IL-8. Relative recovery was related to apparent molecular weight of cytokine and to isoelectric point (pI), a surrogate marker of hydrophilicity. The mean fluid recovery for crystalloid and colloid perfusate was 92% and 145%, respectively. Scanning electron microscopy was utilized to investigate the ultrastructure of microdialysis membranes: (1) 20-kDa membrane, (2) 100-kDa membrane, and (3) ex vivo 100-kDa membrane. The 100-kDa membranes possessed multiple large cavities and the catheter examined after use in human brain clearly demonstrated cellular debris within the pores of the membrane. While colloid perfusate improves relative recovery, it causes a net influx of fluid into the microdialysis catheter, potentially dehydrating the extracellular space. This study is the first to systematically determine relative recovery in vitro for a wide range of cytokines. The two forms of perfusion fluid require direct comparison in vivo.
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Carpenter KLH, Kirkpatrick PJ, Weissberg PL, Challis IR, Dennis IF, Freeman MA, Mitchinson MJ. Oral a-tocopherol Supplementation Inhibits Lipid Oxidation in Established Human Atherosclerotic Lesions. Free Radic Res 2009; 37:1235-44. [PMID: 14703736 DOI: 10.1080/10715760310001604143] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Much experimental evidence suggests that lipid oxidation is important in atherogenesis and in epidemiological studies dietary antioxidants appear protective against cardiovascular events. However, most large clinical trials failed to demonstrate benefit of oral antioxidant vitamin supplementation in high-risk subjects. This paradox questions whether ingestion of antioxidant vitamins significantly affects lipid oxidation within established atherosclerotic lesions. METHODS AND RESULTS This placebo-controlled, double blind study of 104 carotid endarterectomy patients determined the effects of short-term alpha-tocopherol supplementation (500 IU/day) on lipid oxidation in plasma and advanced atherosclerotic lesions. In the 53 patients who received alpha-tocopherol there was a significant increase in plasma alpha-tocopherol concentrations (from 32.66 +/- 13.11 at baseline to 38.31 +/- 13.87 (mean +/- SD) micromol/l, p < 0.01), a 40% increase (compared with placebo patients) in circulating LDL-associated alpha-tocopherol (p < 0.0001), and their LDL was less susceptible to ex vivo oxidation than that of the placebo group (lag phase 115.3 +/- 28.2 and 104.4 +/- 15.7 min respectively, p < 0.02). Although the mean cholesterol-standardised alpha-tocopherol concentration within lesions did not increase, alpha-tocopherol concentrations in lesions correlated significantly with those in plasma, suggesting that plasma alpha-tocopherol levels can influence lesion levels. There was a significant inverse correlation in lesions between cholesterol-standardised levels of alpha-tocopherol and 7beta-hydroxycholesterol, a free radical oxidation product of cholesterol. CONCLUSIONS These results suggest that within plasma and lesions alpha-tocopherol can act as an antioxidant. They may also explain why studies using < 500 IU alpha-tocopherol/day failed to demonstrate benefit of antioxidant therapy. Better understanding of the pharmacodynamics of oral antioxidants is required to guide future clinical trials.
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Howarth S, Li ZY, Trivedi RA, U-King-Im JM, Graves MJ, Kirkpatrick PJ, Gillard JH. Correlation of macrophage location and plaque stress distribution using USPIO-enhanced MRI in a patient with symptomatic severe carotid stenosis: a new insight into risk stratification. Br J Neurosurg 2009; 21:396-8. [PMID: 17676461 DOI: 10.1080/02688690701400775] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
High resolution, USPIO-enhanced MR imaging can be used to identify inflamed atherosclerotic plaque. We report a case of a 79-year-old man with a symptomatic carotid stenosis of 82%. The plaque was retrieved for histology and finite element analysis (FEA) based on the preoperative MR imaging was used to predict maximal Von Mises stress on the plaque. Macrophage location correlated with maximal predicted stresses on the plaque. This supports the hypothesis that macrophages thin the fibrous cap at points of highest stress, leading to an increased risk of plaque rupture and subsequent stroke.
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Tseng MY, Hutchinson PJ, Richards HK, Czosnyka M, Pickard JD, Erber WN, Brown S, Kirkpatrick PJ. Acute systemic erythropoietin therapy to reduce delayed ischemic deficits following aneurysmal subarachnoid hemorrhage: a Phase II randomized, double-blind, placebo-controlled trial. J Neurosurg 2009; 111:171-80. [DOI: 10.3171/2009.3.jns081332] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Delayed ischemic deficits (DIDs), a major source of disability following aneurysmal subarachnoid hemorrhage (aSAH), are usually associated with severe cerebral vasospasm and impaired autoregulation. Systemic erythropoietin (EPO) therapy has been demonstrated to have neuroprotective properties acting via EPO receptors on cerebrovascular endothelia and ischemic neurons. In this trial, the authors explored the potential neuroprotective effects of acute EPO therapy following aSAH.
Methods
Within 72 hours of aSAH, 80 patients (age range 24–82 years) were randomized to receive intravenous EPO (30,000 U) or placebo every 48 hours for a total of 90,000 U. Primary end points were the incidence, duration, and severity of vasospasm and impaired autoregulation on transcranial Doppler ultrasonography. Secondary end points were incidence of DIDs and outcome at discharge and at 6 months.
Results
Randomization characteristics were balanced except for age, with the EPO group being older (mean age 59.6 vs 53.3 years, p = 0.034). No differences were demonstrated in the incidence of vasospasm and adverse events; however, patients receiving EPO had a decreased incidence of severe vasospasm from 27.5 to 7.5% (p = 0.037), reduced DIDs with new cerebral infarcts from 40.0 to 7.5% (p = 0.001), a shortened duration of impaired autoregulation (ipsilateral side, p < 0.001), and more favorable outcome at discharge (favorable Glasgow Outcome Scale score, p = 0.039). Among the 71 survivors, the EPO group had fewer deficits measured with National Institutes of Health Stroke Scale (median Score 2 vs 6, p = 0.008).
Conclusions
This preliminary study showed that EPO seemed to reduce delayed cerebral ischemia following aSAH via decreasing severity of vasospasm and shortening impaired autoregulation.
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Tang TY, Howarth SPS, Miller SR, Graves MJ, Patterson AJ, U-King-Im JM, Li ZY, Walsh SR, Brown AP, Kirkpatrick PJ, Warburton EA, Hayes PD, Varty K, Boyle JR, Gaunt ME, Zalewski A, Gillard JH. The ATHEROMA (Atorvastatin Therapy: Effects on Reduction of Macrophage Activity) Study. Evaluation using ultrasmall superparamagnetic iron oxide-enhanced magnetic resonance imaging in carotid disease. J Am Coll Cardiol 2009; 53:2039-50. [PMID: 19477353 DOI: 10.1016/j.jacc.2009.03.018] [Citation(s) in RCA: 275] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Revised: 01/22/2009] [Accepted: 03/02/2009] [Indexed: 12/19/2022]
Abstract
OBJECTIVES The aim of this study was to evaluate the effects of low-dose (10 mg) and high-dose (80 mg) atorvastatin on carotid plaque inflammation as determined by ultrasmall superparamagnetic iron oxide (USPIO)-enhanced carotid magnetic resonance imaging (MRI). The hypothesis was that treatment with 80 mg atorvastatin would demonstrate quantifiable changes in USPIO-enhanced MRI-defined inflammation within the first 3 months of therapy. BACKGROUND Preliminary studies indicate that USPIO-enhanced MRI can identify macrophage infiltration in human carotid atheroma in vivo and hence may be a surrogate marker of plaque inflammation. METHODS Forty-seven patients with carotid stenosis >40% on duplex ultrasonography and who demonstrated intraplaque accumulation of USPIO on MRI at baseline were randomly assigned in a balanced, double-blind manner to either 10 or 80 mg atorvastatin daily for 12 weeks. Baseline statin therapy was equivalent to 10 mg of atorvastatin or less. The primary end point was change from baseline in signal intensity (DeltaSI) on USPIO-enhanced MRI in carotid plaque at 6 and 12 weeks. RESULTS Twenty patients completed 12 weeks of treatment in each group. A significant reduction from baseline in USPIO-defined inflammation was observed in the 80-mg group at both 6 weeks (DeltaSI 0.13; p = 0.0003) and at 12 weeks (DeltaSI 0.20; p < 0.0001). No difference was observed with the low-dose regimen. The 80-mg atorvastatin dose significantly reduced total cholesterol by 15% (p = 0.0003) and low-density lipoprotein cholesterol by 29% (p = 0.0001) at 12 weeks. CONCLUSIONS Aggressive lipid-lowering therapy over a 3-month period is associated with significant reduction in USPIO-defined inflammation. USPIO-enhanced MRI methodology may be a useful imaging biomarker for the screening and assessment of therapeutic response to "anti-inflammatory" interventions in patients with atherosclerotic lesions. (Effects of Atorvastatin on Macrophage Activity and Plaque Inflammation Using Magnetic Resonance Imaging [ATHEROMA]; NCT00368589).
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Patel HC, Kirkpatrick PJ. High flow extracranial to intracranial vascular bypass procedure for giant aneurysms: indications, surgical technique, complications and outcome. Adv Tech Stand Neurosurg 2009; 34:61-83. [PMID: 19368081 DOI: 10.1007/978-3-211-78741-0_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
High flow extracranial-intracranial (hfEC-IC) vascular bypass remains an important surgical technique in selected patients. For example, in those with giant aneurysms where the natural history of the condition is poor, and direct surgical approaches are recognised as excessively hazardous. hfEC-IC also allows for major carotid vessel occlusion in the treatment of skull base tumours which would otherwise be untreatable. We describe the indications, techniques, complications, and outcomes of this procedure in an era where few neurosurgeons are exposed to high volume vascular neurosurgery, and fewer still are trained to perform hfEC-IC. We emphasise the need for a stereo-typed and meticulous technique, highlighting key points at each stage of the operation, to ensure graft survival and minimal chances of morbidity.
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Langham J, Reeves BC, Lindsay KW, van der Meulen JH, Kirkpatrick PJ, Gholkar AR, Molyneux AJ, Shaw DM, Copley L, Browne JP. Variation in Outcome After Subarachnoid Hemorrhage. Stroke 2009; 40:111-8. [DOI: 10.1161/strokeaha.108.517805] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Tseng MY, Hutchinson PJ, Turner CL, Czosnyka M, Richards HK, Pickard JD, Kirkpatrick PJ. Statin Use Was not Associated with Less Vasospasm or Improved Outcome after Subarachnoid Hemorrhage. Neurosurgery 2008; 63:E1209; author reply E1209. [DOI: 10.1227/01.neu.0000325676.40399.63] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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