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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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Wu C, Ansari SA, Honarmand AR, Vakil P, Hurley MC, Bendok BR, Carr J, Carroll TJ, Markl M. Evaluation of 4D vascular flow and tissue perfusion in cerebral arteriovenous malformations: influence of Spetzler-Martin grade, clinical presentation, and AVM risk factors. AJNR Am J Neuroradiol 2015; 36:1142-9. [PMID: 25721076 DOI: 10.3174/ajnr.a4259] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 12/11/2014] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The role of intracranial hemodynamics in the pathophysiology and risk stratification of brain AVMs remains poorly understood. The purpose of this study was to assess the influence of Spetzler-Martin grade, clinical history, and risk factors on vascular flow and tissue perfusion in cerebral AVMs. MATERIALS AND METHODS 4D flow and perfusion MR imaging was performed in 17 patients with AVMs. Peak velocity and blood flow were quantified in AVM feeding and contralateral arteries, draining veins, and the straight sinus. Regional perfusion ratios (CBF, CBV, and MTT) were calculated between affected and nonaffected hemispheres. RESULTS Regarding flow parameters, high-grade AVMs (Spetzler-Martin grade of >2) demonstrated significantly increased peak velocity and blood flow in the major feeding arteries (P < .001 and P = .004) and straight sinus (P = .003 and P = .012) and increased venous draining flow (P = .001). The Spetzler-Martin grade significantly correlated with cumulative feeding artery flow (r = 0.85, P < .001) and draining vein flow (r = 0.80, P < .001). Regarding perfusion parameters, perinidal CBF and CBV ratios were significantly lower (P < .001) compared with the remote ratios and correlated negatively with cumulative feeding artery flow (r = -0.60, P = .014 and r = -0.55, P = .026) and draining vein flow (r = -0.60, P = .013 and r = -0.56, P = .025). Multiple regression analysis revealed no significant association of AVM flow or perfusion parameters with clinical presentation (rupture and seizure history) and AVM risk factors. CONCLUSIONS Macrovascular flow was significantly associated with increasing Spetzler-Martin grade and correlated with perinidal microvascular perfusion in cerebral AVMs. Future longitudinal studies are needed to evaluate the potential of comprehensive cerebral flow and perfusion MR imaging for AVM risk stratification.
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Affiliation(s)
- C Wu
- From the Department of Biomedical Engineering (C.W., T.J.C., M.M.), McCormick School of Engineering, Northwestern University, Evanston, Illinois Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.)
| | - S A Ansari
- Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.) Neurological Surgery (S.A.A., M.C.H., B.R.B.) Neurology (S.A.A.)
| | - A R Honarmand
- Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.)
| | - P Vakil
- Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.)
| | - M C Hurley
- Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.) Neurological Surgery (S.A.A., M.C.H., B.R.B.)
| | - B R Bendok
- Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.) Neurological Surgery (S.A.A., M.C.H., B.R.B.) Otolaryngology (B.R.B.), Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - J Carr
- Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.)
| | - T J Carroll
- From the Department of Biomedical Engineering (C.W., T.J.C., M.M.), McCormick School of Engineering, Northwestern University, Evanston, Illinois Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.)
| | - M Markl
- From the Department of Biomedical Engineering (C.W., T.J.C., M.M.), McCormick School of Engineering, Northwestern University, Evanston, Illinois Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.)
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Wu P, Liang C, Wang Y, Guo Z, Li B, Qiu B, Li X, Wen Z, Pan Q. Microneurosurgery in combination with endovascular embolisation in the treatment of solid haemangioblastoma in the dorsal medulla oblongata. Clin Neurol Neurosurg 2012; 115:651-7. [PMID: 22906819 DOI: 10.1016/j.clineuro.2012.07.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 07/08/2012] [Accepted: 07/15/2012] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate the treatment of solid haemangioblastomas in the dorsal medulla oblongata using microneurosurgery in combination with endovascular embolisation. METHODS Clinical data from 11 patients with solid haemangioblastomas in the dorsal medulla oblongata who were treated with endovascular embolisation followed by microneurosurgery were analysed retrospectively. Clinical results were evaluated using the modified Rankin scale. The patients were preoperatively evaluated by neuroimaging methods such as magnetic resonance imaging (MRI), contrast MRI and digital subtraction angiography (DSA). General anaesthesia was induced, the patients were tracheally intubated, and the abnormal vessels were embolised. Surgery to resect the haemangioblastoma was conducted after the blood-clotting index returned to normal levels (generally one month after the interventional treatment). RESULTS Embolisation was accomplished in all 11 patients. DSA analysis revealed that most of the tumour vessels and tumour stains disappeared without any complications. The haemangioblastomas were completely resected. None of the patients received blood transfusion or died during surgery. The neurological deficit was reduced or eliminated in 10 patients, but 1 patient died after experiencing an acute myocardial infarction on the tenth postoperative day. No recurrence occurred during follow-up in patients who underwent total tumour resection. Postoperative grades using the modified Rankin scale were improved in all 10 patients. However, several complications occurred, including communicating hydrocephalus, incision infection, pneumonia and cerebrospinal fluid leakage from the incision. Notably, normal perfusion pressure breakthrough (NPPB) did not develop during or after endovascular embolisation or surgery. CONCLUSION Preoperative endovascular embolisation is a safe and effective adjunct treatment. Employing this treatment, solid haemangioblastomas in the dorsal medulla oblongata can be safely and completely resected.
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Affiliation(s)
- Pengfei Wu
- Department of Neurosurgery, the First Affiliated Hospital, China Medical University, 155 Nan Jing Street, He Ping District, Shenyang, Liaoning 110001, China
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Lee KW, Lin YC, Lo CP, Liu CC. Intracerebral hemorrhage following endovascular embolization of brain arteriovenous malformation with a combination of Onyx and n-butyl cyanoacrylate: a case report. Clin Imaging 2012; 36:375-8. [PMID: 22726978 DOI: 10.1016/j.clinimag.2011.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Accepted: 09/14/2011] [Indexed: 10/28/2022]
Abstract
We report a 29-year-old female patient who developed intracerebral hemorrhage 16 h after endovascular embolization of a brain arteriovenous malformation with a combination of liquid embolic agents of Onyx and n-butyl cyanoacrylate. After emergent craniectomy with evacuation of the hematoma, the patient recovered consciousness with mild expressive aphasia. The possible etiology of postembolization brain hemorrhage was discussed, and the literature was reviewed.
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Affiliation(s)
- Kwo-Whei Lee
- Department of Radiology, Changhua Christian Hospital, Changhua, Taiwan
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Miller C, Mirski M. Anesthesia considerations and intraoperative monitoring during surgery for arteriovenous malformations and dural arteriovenous fistulas. Neurosurg Clin N Am 2012; 23:153-64. [PMID: 22107866 DOI: 10.1016/j.nec.2011.09.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The anesthetic considerations for surgical resection of arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs) incorporate many principles that are common to craniotomies for other indications. However, a high-flow, low-resistance shunt results in chronic hypoperfusion of adjacent brain tissue that is vulnerable to ischemia and at high risk for hyperemia and hemorrhage as resection of the lesion redirects blood flow. A comprehensive understanding of AVM pathophysiology and rapidly titratable anesthetic and vasoactive agents allow the anesthesiologist to alter blood pressure targets as resection evolves for optimal patient outcome. Intensive management is continued post-operatively as the brain acclimatizes to new parameters.
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Affiliation(s)
- Christina Miller
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA
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Changes of brain perfusion after endovascular embolization of intracranial arteriovenous malformations visualized by 99mTc-ECD SPECT. Nucl Med Commun 2009; 29:1073-80. [PMID: 18987528 DOI: 10.1097/mnm.0b013e32831392eb] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Published data describing scintigraphic evaluation of perfusion changes in patients with cerebral arteriovenous malformations (AVMs) after embolization are very scarce. The aim of our study was to evaluate these changes by using Tc-ethyl cysteinate dimer single photon emission computed tomography. MATERIALS AND METHODS The examinations were performed in 20 patients before and after the treatment. Voxel-based analysis was used for semiquantitative assessment of single photon emission computed tomography. Hypoperfusion in basal single photon emission computed tomography was diagnosed when asymmetry index was higher than 10% in a cluster volume (CV) greater than 10.0 ml. The change of perfusion between basal and control studies was considered significant when relative difference (RD) was higher than 10% in a CV greater than 10 ml. RESULTS Obliteration of AVMs was total or nearly total in 12 patients and partial in 8 patients, No serious complications were observed after the procedure. Before embolization hypoperfusion in the region of an AVM was seen in 17 cases, perfusion defects in areas distant from an AVM were found in 12 patients. After embolization, perfusion around an AVM deteriorated in 11 patients (CV=10.7-68.7 ml, mean 28.6+/-18.4, RD=14-26%, mean 17.8+/-4.5). Improvement was seen in three cases (CV=13.7-17.7 ml, mean 16+/-2, RD=16.5-20.1%, mean 18.2+/-1.8). Perfusion deterioration in areas distant from AVMs was found in nine cases, improvement in three cases. CONCLUSION The changes of perfusion caused by endovascular embolization of AVM can rely on both deterioration and improvement, and occur in the parenchyma surrounding the AVM and in the distant regions of the brain. Although deterioration of perfusion indicated that more frequent follow-up was necessary, it was not related with serious complications in our group of patients.
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Iwama T, Hayashida K, Takahashi JC, Nagata I, Hashimoto N. Cerebral hemodynamics and metabolism in patients with cerebral arteriovenous malformations: an evaluation using positron emission tomography scanning. J Neurosurg 2002; 97:1314-21. [PMID: 12507129 DOI: 10.3171/jns.2002.97.6.1314] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The purpose of this study was to evaluate cerebral hemodynamic and metabolic features in patients with arteriovenous malformations (AVMs) by using positron emission tomography (PET) scanning. METHODS Twenty-four patients with supratentorial cerebral AVMs participated in PET studies in which 15O inhalation steady-state methods were used. The authors recorded the values of regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV), the regional oxygen extraction fraction (rOEF), and the regional cerebral metabolic rate of O2 (rCMRO2) at three designated regions of interest (ROIs) in each patient. These ROIs included perilesional (ROI-p), ipsilateral remote (ROI-i), and contralateral symmetrical (ROI-c) brain regions. To identify the factors that exert a direct effect on the hemodynamics of brains affected by AVM, we also separated the lesions according to their size and flow type shown on angiograms, and grouped the patients according to the presence or absence of progressive neurological deficits. We then compared the PET parameters at different ROIs in individual patients and evaluated the mean values obtained for all 24 patients according to AVM flow type and size, and the presence or absence of progressive neurological deficits. CONCLUSIONS Overall, mean rCBV and rOEF values were significantly higher in ROI-p than in ROI-c (p = 0.00046 and p = 0.015, respectively). No significant differences were seen between the ROI-i and ROI-c with respect to rCBF, rCBV, and rOEF. Mean rCMRO2 values were similar in the three ROIs; however, the mean rCBF was significantly lower in the ROI-p than in the ROI-c in patients with high-flow AVMs (p = 0.019), large AVMs (p = 0.017), and progressive neurological deficits (p = 0.021). Furthermore, the mean rOEF values were significantly higher in the ROI-p than in the ROI-c in patients with high-flow AVMs (p = 0.005), large AVMs (p = 0.019), and progressive neurological deficits (p = 0.017). The PET studies revealed hemodynamic impairment characterized by decreased rCBF and increased rOEF and rCBV values in the ROI-p of patients with large, high-flow AVMs regardless of whether they exhibited progressive neurological deficits.
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Affiliation(s)
- Toru Iwama
- Department of Neurosurgery, National Cardiovascular Center, Suita, Osaka, Japan.
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