The effect of EC-IC bypass surgery on resting cerebral blood flow and cerebrovascular reserve capacity studied with stable Xe-CT and acetazolamide test

Yamashita, Tetsuo; Kashiwagi, Shiro; Nakano, Shigeki; Takasago, Teiichi; Abiko, Seisho; Shiroyama, Yujiro; Hayashi, Masato; Ito, Hiroki

doi:10.1007/bf00588221

Cited by 74 publications

(34 citation statements)

References 12 publications

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“…After ECIC bypass, several studies have shown that there can be full or partial reversal of impaired CVR (Fig 6). 21,101,102 One study using 133 Xe SPECT in 28 patients who underwent ECIC bypass showed significant improvement of CVR after surgery while the resting CBF was essentially unchanged. 103 Schaller 104 concluded that the hemodynamic parameters observed in patients who experience improved neurologic function or diminished stroke risk profile after ECIC-bypass surgery contain both significantly elevated OEF and CBF/CBV.…”

Section: Pre-and Postoperative Evaluation Of Extracranialintracranialmentioning

confidence: 99%

The Acetazolamide Challenge: Techniques and Applications in the Evaluation of Chronic Cerebral Ischemia

Vagal¹,

Leach²,

Fernández-Ulloa³

et al. 2009

AJNR Am J Neuroradiol

167

116

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SUMMARY:The acetazolamide (ACZ) challenge test is a useful clinical tool and a reliable predictor of critically reduced perfusion. In patients with chronic steno-occlusive disease, the ability to maintain normal cerebral blood flow by reducing vascular resistance secondary to autoregulatory vasodilation is compromised. Identification of the presence and degree of autoregulatory vasodilation (reflecting the cerebrovascular reserve) is a significant prognostic factor in patients with chronic cerebrovascular disease. The pharmacologic challenge of a vasodilatory stimulus such as ACZ can also be used to optimize the treatment strategies for these patients. The pathophysiology, methods, and clinical applications of the ACZ challenge test are discussed in this article. Viability of the cerebral parenchyma is dependent on the ability of the brain vasculature to provide adequate levels of cerebral blood flow (CBF). In patients with chronic stenoocclusive disease, the ability to maintain normal CBF by reducing vascular resistance is compromised. Identification of the degree of autoregulatory vasodilation reflects cerebrovascular reserve (CVR), which is a significant prognostic factor in chronic cerebrovascular disease.1-5 Flow reserve can be assessed with the use of paired blood flow measurements, with the initial measurement obtained at baseline and the second, after a vasodilatory stimulus, such as acetazolamide (ACZ). 6 Pathophysiology of Chronic Cerebrovascular DiseaseChronic cerebral hypoperfusion is usually the result of occlusion or stenosis of large arteries in the neck or the circle of Willis. Clinical symptoms and manifestations of brain ischemia in patients with chronic cerebrovascular disease (CVD) develop as a consequence of 2 main mechanisms: embolic events from atherosclerotic plaques resulting in local compromise of blood flow and systemic hemodynamic alterations that further reduce an already compromised cerebral perfusion state. 7The hemodynamic changes due to a decline in cerebral perfusion pressure have been studied by many investigators. 6,[8][9][10][11] Chronic CBF restriction causes a progressive decrease in cerebral perfusion pressure (CPP). Initially, decreases of CPP cause varying degrees of autoregulatory vasodilation of small distal arterioles.12 Powers 10 and Powers et al 11 proposed a 2-stage classification of hemodynamic impairment in patients with CVD. In stage I (autoregulatory vasodilation), autoregulation reduces cerebral vascular resistance. CBF and oxygen extraction fraction (OEF) are not significantly changed. Increases of cerebral blood volume (CBV) and mean transit time (MTT) are 2 parameters that reflect this initial phase of compensatory autoregulatory vasodilation. Further decreases of CPP beyond cerebral autoregulatory vasodilation capacity eventually result in stage II (autoregulatory failure), characterized by decreases of CBF and increases of OEF. When the CBF decreases, neurons increase the fraction of oxygen extracted from the blood to maintain normal neurologic function. ...

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Section: Pre-and Postoperative Evaluation Of Extracranialintracranialmentioning

confidence: 99%

The Acetazolamide Challenge: Techniques and Applications in the Evaluation of Chronic Cerebral Ischemia

Vagal¹,

Leach²,

Fernández-Ulloa³

et al. 2009

AJNR Am J Neuroradiol

167

116

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“…The details of these specific procedures have been described elsewhere, 8,18,26 and their use for evaluating cerebral perfusion dynamics in moyamoya disease is well established. For Xe-CT, SPECT, and TCD studies, the summary findings for each report were utilized; in this way, numerical values for CBF and velocity were not recorded, but general findings such as, "normal," "impaired," and "exhausted" were.…”

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confidence: 99%

Long-term outcome of superficial temporal artery–middle cerebral artery bypass for patients with moyamoya disease in the US

Mesiwala

Sviri

Fatemi

et al. 2008

FOC

129

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Object The authors report the long-term results of a series of direct superficial temporal artery–middle cerebral artery (STA–MCA) bypass procedures in patients with moyamoya disease from the western US. Methods All patients with moyamoya disease treated at the University of Washington from 1990 through 2004 (39 patients) were included in this study. Patients underwent pre- and postoperative evaluation of cerebral perfusion dynamics. Surgical revascularization procedures were performed in all patients with impaired cerebral blood flow (CBF) findings. Results The mean age of patients at diagnosis was 34 years (range 10–55 years). All 39 patients had impaired CBF and/or vasomotor reserve and underwent revascularization procedures: 26 patients underwent bilateral operations, 13 unilateral (65 total procedures). An STA–MCA bypass was technically possible in 56 procedures (86.2%); saphenous vein interposition grafts were required in 3 procedures (4.6%); encephaloduroarteriosynangiosis was performed in 6 procedures (9.2%). Three patients died due to postoperative complications, yielding a procedure-related mortality rate of 4.61%, and 8 experienced non–life threatening complications (for a procedure-related rate of 12.3%). Long-term follow-up appeared to indicate a reduction in further ischemic events in surviving patients compared with the natural history. Cerebral perfusion dynamics improved postoperatively in all 36 surviving patients. Conclusions Moyamoya disease may differ in the US and Asia, and STA–MCA bypass procedures may prevent future ischemic events in patients with this condition.

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“…A MEDLINE (1985-2007) database search was conducted using the following keywords, singly and in combination: EC-IC bypass, hemodynamic failure, and misery 47 The authors of 15 of these studies used improved resting CBF and/or improved reactivity as an outcome. Of the 10 studies in which postsurgical resting CBF was reported, there was an increase in 5 studies 17,26,28,30,39 and an unchanged or decreased resting CBF in the other 5, 7,31,41,45 for a combined rate of 30% (34/113) of patients showing increased resting CBF.…”

Section: Literature Reviewmentioning

confidence: 99%

The Extracranial–Intracranial Bypass Trial: implications for future investigations

Garrett

Komotar

Merkow

et al. 2008

FOC

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✓The 1985 International Extracranial–Intracranial (EC-IC) Bypass Trial failed to show a surgical benefit of EC-IC bypass in patients with varying degrees of angiographic stenosis. This study was limited by the technology available at the time it was conducted. In the 20 years since, there has been considerable progress in imaging techniques that now enable the identification of a subset of stroke patients with hemodynamic ischemia. In the present study, the authors review the relevant literature and propose a reevaluation of the benefits of the EC-IC bypass procedure using these new imaging techniques. The authors reviewed the admission criteria for the EC-IC Bypass Trial in the light of more recently discovered neurovascular physiology and showed that the imaging criteria used in that trial are not physiologically adequate. A MED-LINE (1985–2007) database search for EC-IC case studies was conducted, and additional studies were identified manually by scrutinizing references from identified manuscripts, major neurosurgical journals and texts, and personal files.

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The effect of EC-IC bypass surgery on resting cerebral blood flow and cerebrovascular reserve capacity studied with stable Xe-CT and acetazolamide test

Cited by 74 publications

References 12 publications

The Acetazolamide Challenge: Techniques and Applications in the Evaluation of Chronic Cerebral Ischemia

The Acetazolamide Challenge: Techniques and Applications in the Evaluation of Chronic Cerebral Ischemia

Long-term outcome of superficial temporal artery–middle cerebral artery bypass for patients with moyamoya disease in the US

The Extracranial–Intracranial Bypass Trial: implications for future investigations

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