scholarly journals Hemodynamics and oxygen extraction in chronic large artery steno-occlusive disease: Clinical applications for predicting stroke risk

2017 ◽  
Vol 38 (9) ◽  
pp. 1584-1597 ◽  
Author(s):  
Colin P Derdeyn
Keyword(s):  
Blood Flow ◽  
Ischemic Stroke ◽  
Carotid Artery ◽  
Stroke Risk ◽  
Arterial Stenosis ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Large Artery ◽  
Extraction Fraction ◽  
Hemodynamic Assessment

Depending on the adequacy of collateral sources of blood flow, arterial stenosis or occlusion may lead to reduced perfusion pressure and ultimately reduced blood flow in the distal territory supplied by that vessel. There are two well-defined compensatory mechanisms to reduced pressure or flow – autoregulatory vasodilation and increased oxygen extraction fraction. Other changes, such as metabolic downregulation, are likely. The positive identification of autoregulatory vasodilation and increased oxygen extraction fraction in humans is an established risk factor for future ischemic stroke in some disease states such as atherosclerotic carotid stenosis and occlusion. The mechanisms by which ischemic stroke may occur are not clear, and may include an increased vulnerability to embolic events. The use of hemodynamic assessment to identify patients with occlusive vasculopathy at an increased risk for stroke is very appealing for several different patient populations, such as those with symptomatic intracranial atherosclerotic disease, moyamoya phenomenon, complete internal carotid artery occlusion, and asymptomatic cervical carotid artery stenosis. While there is very good data for stroke risk prediction in some of these groups, no intervention based on these tools has been proven effective yet. In this manuscript, we will review these topics above and identify areas for future research.

Reversal of Focal Misery Perfusion after Intracranial Angioplasty: Case Report

Neurosurgery ◽  
2001 ◽  
Vol 48 (2) ◽  
pp. 436-440 ◽  
Author(s):  
Colin P. Derdeyn ◽  
DeWitte T. Cross ◽  
Christopher J. Moran ◽  
Ralph G. Dacey
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Artery ◽  
Intracranial Stenosis ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Positron Emission ◽  
Misery Perfusion ◽  
Before And After ◽  
Hemodynamic Measurements

Abstract OBJECTIVE AND IMPORTANCE The presence of reduced blood flow and increased oxygen extraction fraction (OEF) (misery perfusion) in the hemisphere distal to an occluded carotid artery is a proven risk factor for subsequent stroke. Whether angioplasty of intracranial stenosis is sufficient to reverse this condition has not been documented. CLINICAL PRESENTATION A 67-year-old man exhibited progressive right hemispheric ischemic symptoms despite maximal antiplatelet and antithrombotic therapy. Angiography demonstrated focal 80% stenosis of the supraclinoid segment of the ipsilateral internal carotid artery. TECHNIQUE 15O positron emission tomographic measurements of cerebral blood flow and OEF were made before and after transfemoral percutaneous angioplasty. OEF values measured before angioplasty were elevated in the middle cerebral artery distal to the stenosis. Angioplasty reduced the degree of luminal stenosis to 40% (linear diameter). OEF values measured 36 hours after angioplasty were normal. CONCLUSION Angioplasty of intracranial stenosis can restore normal cerebral blood flow and oxygen extraction, despite mild residual stenosis after the procedure. Hemodynamic measurements may be useful for the identification of patients with the greatest potential to benefit from angioplasty.

Abstract W P115: Utilization of Blood Sampling Global Oxygen Extraction Fraction and SPECT to Anticipate Cerebral Hyperperfusion Syndrome Following Elective Carotid Artery Stenting

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Takahisa Mori ◽  
Tomonori Iwata ◽  
Yuhei Tanno ◽  
Shigen Kasakura ◽  
Yoshinori Aoyagi ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Carotid Artery Stenting ◽  
Blood Sampling ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Cerebral Hyperperfusion Syndrome ◽  
Hyperperfusion Syndrome ◽  
Cerebral Hyperperfusion ◽  
Arterial Blood ◽  
Extraction Fraction

Background: It is required to anticipate cerebral hyperperfusion syndrome (CHS) following carotid artery stenting (CAS). Purpose: The purpose of our retrospective study was to investigate whether or not blood sampling oxygen extraction fraction (OEF) and post-CAS CBF increase in SPECT had relation to CHS following CAS. Methods: Included in our analysis were patients (1) who underwent elective CAS in our institution between October 2010 and May 2014, and (2) who underwent blood sampling for OEF calculation before and immediately after CAS, and (3) who underwent SPECT before and just after CAS. OEF was calculated from cerebral arteriovenous oxygen difference. Arterial blood was sampled from the common carotid artery and venous blood from the dominant-sided superior jugular bulb. CHS was defined as pulsatile headaches, restlessness, convulsion, and/or new neurological symptoms not due to cerebral ischemia within seven days following CAS. CBF was measured before and just after CAS. CBF increase in the CAS side was defined as follows; (post-CAS CBF ratio - pre-CAS CBF ratio) of more than 10%, where CBF ratio was defined as CAS-sided fronto-parietal CBF divided by ipsilateral cerebellar CBF (%). Evaluated were baseline features in patients, pre-CAS OEF, post-CAS OEF, CBF ratio, CBF increase and CHS. Results: During the study period, 134 patients matched our criteria for analysis. Pre-CAS OEF was 0.41+-0.06, post-CAS OEF was 0.42+-0.08, pre-CAS CBF ratio: 88.7+-15.4%, CBF increase: 1.86+-12.3%. Nine patients presented CHS. Among them, pre-CAS OEF, CBF ratio and CBF increase were significant. ROC curves showed that pre-CAS OEF of 0.46 (p<0.001, OR: 9.3), CBF ratio of 92%(p<0.05, OR: 6.5), CBF increase of 8.8% (p<0.005, OR: 6.6) were cut-off values. Among 10 patients with pre-CAS OEF of more than 0.46 and CBF increase of more than 8.8%, 4 patients presented CHS (p<0.0001, OR;15.9). Conclusion: Elevation of pre-CAS OEF and increase of post-CAS CBF were strongly related to CHS.

Global Oxygen Extraction Fraction by Blood Sampling to Anticipate Cerebral Hyperperfusion Phenomenon After Carotid Artery Stenting

Neurosurgery ◽  
2014 ◽  
Vol 75 (5) ◽  
pp. 546-551 ◽  
Author(s):  
Tomonori Iwata ◽  
Takahisa Mori ◽  
Yuichi Miyazaki ◽  
Yuhei Tanno ◽  
Shigen Kasakura ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Artery ◽  
Carotid Artery Stenting ◽  
Blood Sampling ◽  
Oxygen Extraction Fraction ◽  
Cerebral Hyperperfusion Syndrome ◽  
Hyperperfusion Syndrome ◽  
Cerebral Hyperperfusion ◽  
Extraction Fraction

Abstract BACKGROUND: Cerebral hyperperfusion syndrome sometimes occurs after carotid revascularization in patients with severe hemodynamic failure. To prevent cerebral hyperperfusion syndrome, cerebral hyperperfusion phenomenon (CHP) must be detected early. Single-photon emission computed tomography (SPECT) is useful for detecting CHP, but it is impractical on a daily basis. A tool with high availability to find CHP is desired. OBJECTIVE: To investigate whether global oxygen extraction fraction (OEF) by a blood sampling method is useful for indicating CHP after carotid artery stenting (CAS). METHODS: When patients underwent elective CAS from September 2010 to August 2012, we performed blood sampling for OEF calculation and SPECT before and immediately after elective CAS. Data were collected prospectively. OEF was calculated from the cerebral arteriovenous oxygen difference. Cerebral blood flow was measured in the affected middle cerebral artery (MCA) territory and in the ipsilateral cerebellum by SPECT. The ratio of MCA to cerebellar activity was defined as cerebral blood flow in the affected MCA territory divided by cerebral blood flow in the ipsilateral cerebellar hemisphere. Probable CHP was defined as ≥10% increase in the ratio of MCA to cerebellar activity after CAS. The relationship between peri-CAS OEF and probable CHP was evaluated. RESULTS: Of the 96 patients enrolled, 92 patients were analyzed. Probable CHP occurred in 17 patients. Post-CAS OEF was related to probable CHP (P &lt; .01), but pre-CAS OEF was not. The receiver-operating characteristic curve showed that the cutoff value was 45% for probable CHP (P &lt; .001). CONCLUSION: An increase in blood sampling OEF immediately after CAS was related to probable CHP; then the oxygen demand should be reduced.

scholarly journals Effect of ephedrine and phenylephrine on brain oxygenation and microcirculation in anaesthetised patients with cerebral tumours: study protocol for a randomised controlled trial

BMJ Open ◽  
2017 ◽  
Vol 7 (11) ◽  
pp. e018560 ◽  
Author(s):  
Klaus Ulrik Koch ◽  
Anna Tietze ◽  
Joel Aanerud ◽  
Gorm von Öettingen ◽  
Niels Juul ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Metabolic Rate ◽  
Transit Time ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Brain Oxygenation ◽  
Cerebral Metabolic Rate ◽  
Arterial Blood ◽  
Extraction Fraction

IntroductionDuring brain tumour surgery, vasopressor drugs are commonly administered to increase mean arterial blood pressure with the aim of maintaining sufficient cerebral perfusion pressure. Studies of the commonly used vasopressors show that brain oxygen saturation is reduced after phenylephrine administration, but unaltered by ephedrine administration. These findings may be explained by different effects of phenylephrine and ephedrine on the cerebral microcirculation, in particular the capillary transit-time heterogeneity, which determines oxygen extraction efficacy. We hypothesised that phenylephrine is associated with an increase in capillary transit-time heterogeneity and a reduction in cerebral metabolic rate of oxygen compared with ephedrine. Using MRI and positron emission tomography (PET) as measurements in anaesthetised patients with brain tumours, this study will examine whether phenylephrine administration elevates capillary transit-time heterogeneity more than ephedrine, thereby reducing brain oxygenation.Methods and analysisThis is a double-blind, randomised clinical trial including 48 patients scheduled for surgical brain tumour removal. Prior to imaging and surgery, anaesthetised patients will be randomised to receive either phenylephrine or ephedrine infusion until mean arterial blood pressure increases to above 60 mm Hg or 20% above baseline. Twenty-four patients were allocated to MRI and another 24 patients to PET examination. MRI measurements include cerebral blood flow, capillary transit-time heterogeneity, cerebral blood volume, blood mean transit time, and calculated oxygen extraction fraction and cerebral metabolic rate of oxygen for negligible tissue oxygen extraction. PET measurements include cerebral metabolic rate of oxygen, cerebral blood flow and oxygen extraction fraction. Surgery is initiated after MRI/PET measurements and subdural intracranial pressure is measured.Ethics and disseminationThis study was approved by the Central Denmark Region Committee on Health Research Ethics (12 June 2015; 1-10-72-116-15). Results will be disseminated via peer-reviewed publication and presentation at international conferences.Trial registration numberNCT02713087; Pre-results. 2015-001359-60; Pre-results.

13.22 Effect of dobutamine on myocardial blood flow and oxygen extraction fraction

2001 ◽  
Vol 8 (1) ◽  
pp. S83-S83
Author(s):  
E TADAMURA ◽  
M MAMEDE ◽  
K MATSUMOTO ◽  
S KUBO ◽  
H IIDA ◽  
...  
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Extraction Fraction
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