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PubMed1987

Experimental study on the reversibility of cerebral ischemia. Residual blood flow and duration of ischemia.

The flow threshold and time threshold for reversibility of cerebral ischemia were studied using a canine model of cerebral ischemia regulated by controlled perfusion of cerebral blood flow (CBF). CBF was continuously monitored with a laser Doppler flow meter, the brain was brought to a constant level of ischemia for a defined period of time, after which recirculation was instituted. The electroencephalogram (EEG) and somatosensory evoked potentials (SEP) were monitored and used as an index of brain function. No recovery of brain function was found following recirculation if the CBF was reduced to a level below 20% of the normal state for more than one hour. When residual blood flow was 30% of the normal level, however, recirculation after one hour of ischemia resulted in nearly complete recovery of brain function. Significant functional recovery was not seen after two or more hours of such ischemia. Nearly complete recovery was also seen following reperfusion within three hours with 40% of normal CBF. It was demonstrated that the reversibility in the ischemic brain was critically correlated to the level of blood flow and its duration. If these results can be applied to the human brain, emergency cerebral revascularization for ischemic stroke should be attempted when critical flow and time thresholds have not been crossed, namely, in less than 1 hour and 3 hours of insult when the residual blood flow is reduced to 30 and 40% of the normal state, respectively. In clinical situations, this "critical time" may be too short for acute revascularization unless cerebral protective measures are applied pre-operatively to prolong the viability period of ischemic cerebral tissue.

Animals↗
PubMed2005

Intraoperative control of extracranial-intracranial bypass patency by near-infrared indocyanine green videoangiography.

OBJECT: Recently, intraoperative fluorescence angiography in which indocyanine green (ICG) is used as a tracer has been introduced as a novel technique to confirm successful aneurysm clipping. The aim of the present study was to assess whether ICG videoangiography is also suitable for intraoperative confirmation of extracranial-intracranial bypass patency. METHODS: Forty patients undergoing cerebral revascularization for hemodynamic cerebral ischemia (11 patients), moya-moya disease (18 patients), or complex intracranial aneurysms (11 patients) were included. Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery was performed 35 times in 30 patients (five patients with moyamoya underwent bilateral procedures), STA-posterior cerebral artery bypass surgery in two patients, and saphenous vein (SV) high-flow bypass surgery in eight patients. In each patient, following the completion of the anastomosis, ICG (0.3 mg/kg body weight) was given systemically via an intravenous bolus injection. A near-infrared light emitted by laser diodes was used to illuminate the operating field and the intravascular fluorescence was recorded using an optical filter-equipped video camera. The findings of ICG videoangiography were compared with those of postoperative digital subtraction (DS) or computerized tomography (CT) angiography. In all cases excellent visualization of cerebral arteries, the bypass graft, and brain perfusion was noted. Indocyanine green videoangiography was used to identify four nonfunctioning STA-MCA bypasses, which could be revised successfully in all cases. In two cases of SV high-flow bypasses, ICG videoangiography revealed stenosis at the proximal anastomotic site, which was also revised successfully. In all cases the final findings of ICG videoangiography could be positively validated during the postoperative course by performing DS or CT angiography. CONCLUSIONS: Indocyanine green videoangiography provides a reliable and rapid intraoperative assessment of bypass patency. Thus, ICG videoangiography may help reduce the incidence of early bypass graft failure.

Adolescent↗
PubMed1997

Anastomosis of the superficial temporal artery to the middle cerebral artery with the interposed occipital artery graft in moyamoya disease: case report.

BACKGROUND: Although there have been various interposed bypass grafts used for cerebral revascularization, the occipital artery has never been used as a graft. Interposed occipital artery bypass graft in an adult case with moyamoya disease after failed indirect revascularization is presented. CASE DESCRIPTION: This 34-year-old woman with moyamoya disease, who had suffered from cerebral ischemic symptoms since the age of 6 years, was admitted to our hospital because of an intracerebral hemorrhage on the left side. She had undergone superficial temporal-to-middle cerebral artery anastomosis, encephalo-galeo-synangiosis on the right side, and encephalo-duro-arterio-synangiosis on the left side at age 29 years. Four months after the intracerebral hemorrhage, she still had cerebral ischemic symptoms in the left hemisphere where cerebral revascularization was poor. Since neither the superficial temporal nor occipital artery could be used for direct anastomosis because of spontaneous transdural anastomoses of the superficial temporal artery and the short length of the occipital artery, anastomosis between the left superficial temporal artery and left posterior parietal artery was performed using a left occipital artery graft 6 months after the hemorrhage. Postoperative external carotid angiograms showed good patency of the graft. CONCLUSION: In cases in which direct anastomosis is infeasible for cerebral revascularization, the occipital artery could successfully be used as a bypass graft.

Adult↗
PubMed2005

Moyamoya syndrome associated with Down syndrome: outcome after surgical revascularization.

OBJECTIVES: This study was undertaken to describe the clinical, radiologic, and angiographic features of moyamoya syndrome in a surgical series of children and adults with Down syndrome. We wished to define the features of moyamoya syndrome associated with Down syndrome and to determine the results of surgical revascularization among these patients at early and late follow-up times. METHODS: We reviewed the clinical, radiologic, and angiographic records of all patients with moyamoya syndrome associated with Down syndrome, as a subset of a previously reported, consecutive series of patients who underwent cerebral revascularization surgery with a standardized surgical procedure, pial synangiosis, between January 1, 1985, and June 30, 2004. RESULTS: Of 181 patients with moyamoya syndrome from the initial series who were treated surgically during the study period, 16 patients had Down syndrome (10 female patients and 6 male patients). The average age at onset was 9.3 years (range: 1-29 years); the average age at the time of surgery was 9.8 years (range: 2-29 years). Although the presenting symptoms were transient ischemic attacks for 10 patients and strokes for 6 patients, computed tomographic and/or MRI scans demonstrated bilateral infarctions for 9 patients and unilateral infarctions for 6, with only 1 patient having no imaging evidence of a previous stroke. No cases presented with intracerebral hemorrhage. Preoperative angiography showed the presence of bilateral moyamoya syndrome changes for all patients, including posterior circulation involvement for 8 patients. Surgical treatment included pial synangiosis for all patients, although 1 patient underwent a superficial temporal artery-middle cerebral artery bypass in the contralateral hemisphere. Surgical complications included symptomatic subdural hematomas requiring evacuation, at 48 days and 54 days postoperatively (2 cases), seizures (2 cases), and strokes within 30 days after surgery, at 1 day and 7 days postoperatively (2 cases). Late clinical and radiologic follow-up data (average: 67.6 months; range: 6-146 months) demonstrated no worsening in neurologic status for any patient except for 1 patient who developed a seizure disorder with associated chronic hypocalcemia; she was totally dependent at the 10-year follow-up evaluation, despite no evidence of new infarction since her surgery. There was no clinical or radiologic evidence of new infarction for any patient in late follow-up evaluations. Postoperative angiography, conducted 1 year after surgery for 11 patients, revealed radiologic evidence of good to excellent cerebral revascularization in 85% of the surgically treated hemispheres. Patients were maintained on lifetime aspirin therapy. CONCLUSIONS: The clinical, radiologic, and angiographic features of moyamoya syndrome associated with Down syndrome seem comparable to those of primary moyamoya disease. Cerebral revascularization surgery with the pial synangiosis technique seems to confer long-lasting protection against additional strokes in this patient population. The presence of moyamoya syndrome should be considered in the evaluation of patients with Down syndrome who present with transient ischemic attack-like symptoms.

Adolescent↗
PubMed2001

Posterior cerebral circulation revascularization.

Posterior circulation revascularization has evolved as a method to treat selected patients with vertebrobasilar ischemia who have inaccessible atherosclerotic occlusive disease and who have failed maximal medical therapy. In addition, complex unclippable aneurysms of the posterior circulation are another indication for revascularization of the vertebrobasilar territory. Careful preoperative evaluation and meticulous attention to detail intraoperatively yield good patient outcomes with minimal morbidity and mortality. This article reviews the vascular anatomy of the posterior circulation and the indications, preoperative evaluation, operative techniques, clinical outcomes, and alternative treatments for patients requiring posterior circulation revascularization procedures.

Aged↗
PubMed1997

Middle cerebral artery revascularization. Anatomical studies and considerations on the anastomosis site.

In the surgical management of skull base lesions and vascular diseases such as giant aneurysms, involvement of the internal carotid artery may require the resection or the occlusion of the vessel. The anastomosis of the external carotid artery and the middle cerebral artery with venous graft may be indicated to re-establish the blood flow. To determine the best suture site in the middle cerebral artery, an anatomical study was carried out. Fourteen cerebral hemispheres were analysed after the injection of red latex into the internal carotid artery. The superior and inferior trunk of the main division of the middle cerebral artery have more than 2 mm of diameter. They are superficial allowing an anastomosis using a venous graft. The superior trunk has a disadvantage, it gives rise to branches for the precentral and post-central giri. The anastomosis with the inferior trunk presents lower risk of neurological deficit even though the angular artery originates from it.

Anastomosis, Surgical↗
PubMed1983

[Dynamic pathophysiology of cerebral infarction and revascularization. III. Changes of regional cerebral blood flow].

Thirty-eight patients with occlusive cerebrovascular disease were followed with regional cerebral blood flow (rCBF) measurement, angiography and computerized tomography (CT) to know the time course of rCBF in cerebral infarction. The rCBF study was carried out by the 133Xe intracarotid injection method with 16 scintillation detectors. They were allocated to two groups according to the findings on angiograms; 15 patients having any change of occlusive lesion (the group of no-recanalization ) and 23 patients showing reopening of occluded vessels (the group of recanalization). A mass sign and an extent of cerebral infarction were observed on CT. In the group of no-recanalization, a mean value of rCBF (mean rCBF) in acute stage was well correlated to the severity of ischemic stroke. In minor completed strokes the average mean rCBF was 35.8 +/- 3.7 ml/100g/min, which is significantly higher than that in major strokes and progressing strokes of 24.8 +/- 3.9 ml/100 g/min (p less than 0.001). Sequential change of mean rCBF was not prominent in the group of no-recanalization. However, rCBF change was conspicuous in the group of recanalization. In acute stage of recanalization, rCBF were markedly affected by the presence of mass sign (cerebral edema) on CT. When CT showed midline shift of structure, mean rCBF was markedly reduced, and when without midline shift, focal hyperemic areas were sometimes observed in the revascularized area. Thus, the inhomogeneity of rCBF was characteristic in cases with recanalization. The focal hyperemia usually disappeared within one week in cases of minor stroke and lasted until 2 or 3 weeks in cases of major stroke. In chronic stage, mean rCBF decreased, and there was no significant difference of averaged rCBF between two groups. Those findings suggests that the main factor influenced on the sequential change of rCBF is reopening of occluded vessels. Regional CBF may depends both on the degree of cerebral edema and the extent of vasoparesis after revascularization. In chronic stage CBF value is not always dependent to the presence of occlusive lesion but might be reflected in the total brain function.

Aged↗
PubMed2002

[The role of the extra-intracranial anastomosis and interventionist endovascular therapy in the treatment of complex cerebral aneurysms].

Cerebral revascularization is an useful tool in the treatment of giant or complex cerebral aneurysms that can not be clipped directly by different causes. In turn, interventionist endovascular therapy, an emergent technique with very good results in the treatment of cerebral aneurysms during the last five years, is a new complementary tool to cerebral revascularization for the treatment of complex aneurysms. In the present manuscript we emphasize the beneficial effect of revascularization, followed in a short period of time by the endovascular technique in order to either occlude the parent vessel or to exclude the aneurysm from cerebral circulation. Advantages of this form of therapy, as well as the selection of patients and the present revascularization procedures, are commented.

Aged↗
PubMed1998

Revascularization and bypass procedures for cerebral aneurysms.

Revascularization and bypass procedures are useful in the treatment of complex aneurysms. Extracranial to intracranial bypass grafts are used to augment the distal circulation as an adjunct to proximal vessel occlusion for aneurysm treatment. Bypass grafts are used also to ensure adequate distal circulation during aneurysm trapping procedures. Recent improvements in vascular exposures at the skull base have allowed the development of vessel replacement or interposition grafts for arteries harboring aneurysms at the skull base. Intracranial interposition grafts are used to reconstruct arteries harboring aneurysms that cannot be occluded directly using clip or coil techniques. These techniques in the treatment of cerebral aneurysms are discussed.

Anastomosis, Surgical↗
PubMed2003

Conduits for cerebrovascular bypass and lessons learned from the cardiovascular experience.

Direct cerebral revascularization is an important procedure in the treatment of certain complex aneurysms and skull base tumors when acute sacrifice of the internal carotid artery is required. It likely remains an appropriate treatment in a small subgroup of patients with cerebral ischemia refractory to maximal medical management. Similar to cardiovascular surgery, the choice of a graft conduit is critical for a successful outcome. The standard conduits are interposition vein grafts (usually the greater saphenous vein), free arterial grafts (radial artery), and pedicled arterial grafts (superficial temporal artery). The goal of this review is to summarize the conduits commonly used in cerebral revascularization with emphasis on their patency rates and flow characteristics. Comparisons are made with similar data available in the cardiovascular literature.

Blood Flow Velocity↗
PubMed2000

Extracranial-intracranial bypass for ischemic cerebrovascular disease refractory to maximal medical therapy.

OBJECTIVE: To examine the potential role of cerebral revascularization in the treatment of patients with symptomatic occlusive cerebrovascular disease refractory to medical therapy. METHODS: Twenty patients with symptomatic occlusive cerebrovascular disease underwent 22 extracranial-intracranial bypass procedures after failing maximal medical therapy. The average follow-up time was 3.5 years, and no patient was lost to follow-up. RESULTS: All patients presented with repeated transient ischemic attacks refractory to medical therapy. Angiographic findings included internal carotid artery occlusion in 8 patients, middle cerebral artery stenosis or occlusion in 4, moyamoya disease in 4, internal carotid artery dissection in 2, and supraclinoid internal carotid artery stenosis in 2. Outcome was excellent in 17 patients and good in 3. The only surgical complication occurred in one patient, who experienced postoperative seizures and required anticonvulsant therapy. There were no deaths in this series. CONCLUSION: Although the Cooperative Study on Extracranial-Intracranial Bypass failed to show a benefit from the bypass procedure, we have continued to perform the operation in selected cases. Carefully selected individuals with occlusive cerebrovascular disease and persistent ischemic symptoms, despite maximal medical therapy, seem to obtain demonstrable and durable benefit from cerebral revascularization.

Adolescent↗
PubMed2001

[Single-staged operation for the patients with concomitant diseases of coronary and carotid arteries].

The authors describe four cases with concomitant coronary and carotid severe stenosis operated by combined procedure. As the cerebral revascularization, carotid endarterectomy (CEA) was performed for three patients, while carotid artery bypass grafting was performed for the other one. In one patient with bilateral carotid stenosis, percutaneous transluminal stenting of the right internal carotid artery was performed one day before combined left CEA and coronary artery bypass grafting (CABG). Both perioperative myocardial infarction and neurological complication could be avoided in each case. When a CABG candidate also has significant extracranial carotid stenosis with clinical symptoms, combined cerebral revascularization and CABG is desirable.

Aged↗
PubMed1986

Aneurysms of the posterior cerebral artery: report of ten cases.

Ten cases of posterior cerebral artery (PCA) aneurysm are presented. There were 13 aneurysms in the 10 patients: 6 saccular, 5 fusiform, 1 broad-based, and 1 giant fusiform serpentine aneurysm. Eight patients underwent operation: clipping for 2 saccular aneurysms, trapping for 1 saccular and 3 fusiform aneurysms, and coating for 2 fusiform or broad-based aneurysms. Microsurgical cerebral revascularization techniques were attempted in 2 cases: after a fusiform aneurysm had been excised, end-to-end anastomosis of the residual two ends of the PCA was performed and, after a giant serpentine aneurysm had been trapped, the superficial temporal artery was anastomosed transcortically to the distal PCA. Two patients died before operation because of rebleeding and vasospasm. Postoperative neurological deficits include contralateral hemiparesis, homonymous hemianopsia, hemihypesthesia, and ipsilateral 3rd nerve palsy. Our results suggest that, despite the good collateral circulation of the PCA, some ischemic events may occur after trapping procedures and that cerebral revascularization techniques may have some benefit in the treatment of unclippable aneurysms in this region.

Adolescent↗
PubMed2003

Extracranial-intracranial bypass for symptomatic occlusive cerebrovascular disease not amenable to carotid endarterectomy.

OBJECT: The role of cerebral revascularization remains unclear in symptomatic occlusive cerebrovascular disease refractory to medical therapy. Despite the disappointing findings of the Cooperative Study on Extracranial-Intracranial Bypass, a subpopulation of patients with ischemic cerebrovascular disease and poor hemodynamic reserve may benefit from extracranial-intracranial (EC-IC) bypass. The authors reviewed the records of 65 patients who underwent 71 EC-IC bypass procedures at their institution over the past 6 years. METHODS: All patients except one presented with repeated transient ischemic attacks (TIAs) that were referable to the involved vascular region. Eight patients underwent EC-IC bypass urgently for "crescendo" TIAs refractory to antiplatelet and anticoagulation therapy. Indications for surgery included cervical internal carotid artery (ICA) occlusion in 28, supraclinoid ICA stenosis in two, middle cerebral artery stenosis or occlusion in 14, moyamoya disease in 18, and ICA dissection in three. Cerebral angiography demonstrated poor collateral flow to the involved region in each case. There were no postoperative strokes or deaths in this series. Following EC-IC bypass, the vast majority (95.4%) of patients experienced cessation of their ischemic events and stabilization of preexisting neurological dysfunction. Of the eight patients who underwent EC-IC bypass urgently for crescendo TIAs, two awoke with increased neurological deficits that improved rapidly within 24 hours of surgery. CONCLUSIONS: Although the Cooperative Study failed to show benefit from this treatment modality, the authors have continued to perform EC-IC bypass in certain cases. Carefully selected individuals with occlusive cerebrovascular disease and persistent ischemic symptoms refractory to maximal medical therapy appear to benefit from cerebral revascularization.

Adult↗
PubMedDate not supplied

Cerebral arterial revascularization: the value of repeated angiography in selection of patients for operation.

Three patients with occlusive cerebrovascular disease were evaluated for possible extracranial-intracranial arterial anastomosis. Cerebral angiography repeated at a later date revealed disappearance of the initial vascular stenosis or occlusion and development of extensive collateral circulation. It was concluded in these cases that surgical revascularization would not improve upon natural revascularization. Repeated angiography provides information of value to the physician who must make a decision about such surgical treatment.

Carotid Artery Diseases↗
PubMed1987

[Exploratory hierarchy and surgical indications for carotid surgery in patients with coronary disease].

The major cause of death from carotid artery surgery (1.2% in 1984 in this series) is still coronary disease and myocardial infarct. A series of 50 patients were randomly selected for detailed study of post-operative cardiologic complications and the following sequelae were noted: mortality = 1 myocardial infarct; morbidity = 1 myocardial infarct, 3 documented anginal pains, 8 repolarization disorders, 4 benign ventricular arrhythmias. Analysis of these complications and a literature review demonstrated: the high frequency of combined carotid artery and coronary artery stenosis even in asymptomatic patients (25 to 40% of cases); the elevated percentage of complications in patients with symptomatic coronary disease (mortality risk multiplied by ten), hypertension or arterial disease; the low effect of age taken alone as risk factor. Pre-operative explorations to detect angina, particularly when latent and asymptomatic, should include a questionnaire, strict patient clinical examination and detailed reading of electrocardiogram tracings. An effort test should be performed as a function of results and patients' medical history and when positive should lead to coronarography in patients under 70 in good general condition, and when doubt persists after the effort tests. The indication for surgical treatment is dependent on results of these explorations: Carotid artery surgery (stenosis with high cerebral risk) should be performed under pre- and post-operative myocardial protection in patients with coronary artery disease who are too old or inoperable for cardiac reasons. Simultaneous myocardial and cerebral revascularization in the presence of severe lesions and at equivalent risk of progression. First intention carotid artery surgery for bilateral stable lesions with subsequent simultaneous myocardial and cerebral revascularization. First intention carotid artery surgery in case of cerebral ischemia with coronary artery shunt surgery at a later stage. Improved exploration of patients and close cooperation between cardiologists, anaesthetists and surgeons should allow patients at high risk to be operated upon under improved conditions of safety.

Aged↗
PubMed2005

Vertebral artery-to-middle cerebral artery bypass with coil embolization of giant internal carotid artery aneurysm: technical case report.

OBJECTIVE AND IMPORTANCE: Cerebral revascularization with extracranial-to-intracranial bypass is often required during the surgical treatment of complex intracranial aneurysms. This report is the first in which a vertebral artery (VA)-to-middle cerebral artery (MCA) bypass in conjunction with endovascular coil embolization is used in the successful treatment of a giant intracranial aneurysm. CLINICAL PRESENTATION: A 68-year-old man previously diagnosed with a 6-cm internal carotid artery (ICA) aneurysm presented complaining of progressing left hemiparesis and mental status changes. His aneurysm had been treated previously by common carotid artery occlusion 20 years earlier. Arteriography defined the partially thrombosed, right supraclinoid ICA aneurysm arising at the junction of the posterior communicating artery and the supraclinoid ICA. INTERVENTION: Because of the patient's worsening symptomatology, endovascular coiling with placement of a superficial temporal artery-to-MCA bypass was performed. The patient tolerated this procedure well, and his symptoms resolved. However, they recurred several months later, and imaging suggested poor right hemispheric perfusion despite a patent bypass. A VA-MCA bypass using a saphenous vein graft was then performed using the distal right VA at the level of cervical vertebra 1 (C1) as the donor vessel with a distal anastomotic site on the right MCA. Coil embolization of the aneurysm was repeated, and the feeding posterior communicating artery was sacrificed. The patient is currently asymptomatic more than 1 year after the second bypass and coil embolization. CONCLUSION: This report describes a safe and definitive treatment option for a giant intracranial ICA aneurysm using a posterior-to-anterior circulation (VA-MCA) bypass, followed by endovascular coil embolization in a patient with previous ligation of the common carotid artery. VA-MCA high-flow saphenous vein bypass followed by coil embolization is a useful technique that is especially valuable in the subset of giant aneurysm patients who have previously been treated by carotid ligation.

Aged↗