Showing papers on "Cerebral Revascularization published in 2003"

Symptomatic Cavernous Sinus Aneurysms: Management and Outcome After Carotid Occlusion and Selective Cerebral Revascularization

Abstract: BACKGROUND AND PURPOSE: Therapeutic internal carotid artery (ICA) occlusion for symptomatic intracavernous artery aneurysms can result in ischemic infarction despite normal clinical balloon test occlusion (BTO). We evaluated outcomes in patients with symptomatic cavernous sinus aneurysms in whom clinical BTO was normal, who underwent carotid occlusion with selective bypass surgery guided by physiologic BTO using quantitative cerebral blood flow (CBF) analysis by means of stable xenon-enhanced CT. METHODS: After a normal clinical BTO, 26 consecutive patients with symptomatic cavernous sinus aneurysms underwent a baseline xenon-enhanced CT CBF analysis followed by a second CBF analysis, during which repeat BTO was performed. Patients with a decrease in cortical CBF to below 30 mL/100 g/min were considered moderate risk and those with greater than 30 mL/100 g/min were low risk for developing postocclusion ischemic infarction. Moderate-risk patients underwent cerebral revascularization followed by proximal carotid occlusion. Low-risk patients underwent carotid occlusion alone. Patients were clinically followed up for at least 3 months after carotid occlusion. All patients underwent head CT at least 1 month after carotid occlusion. RESULTS: Eight patients were moderate risk and 18 low risk. Mean follow-up was 15.3 months. Mean CT follow-up was 10.2 months. No low-risk patient developed a postocclusion ischemic deficit by examination or infarct by CT. One patient in the moderate-risk group developed right hemiparesis and a left posterior middle cerebral artery infarction by CT 2 months after carotid occlusion. CONCLUSION: In this series, BTO combined with quantitative CBF analysis was a safe and reliable technique for identification of patients at risk for ischemic infarction after carotid occlusion, despite a normal clinical BTO.

Monitoring of Cerebral Vasodilatory Capacity With Transcranial Doppler Carbon Dioxide Inhalation in Patients With Severe Carotid Artery Disease

Abstract: Background and Purpose— Cerebral vasodilatory capacity (CVC) testing with transcranial Doppler has been shown to be useful in the assessment of stroke risk in patients with symptomatic and asymptomatic internal carotid artery (ICA) stenosis and occlusion, but whether hemodynamic status improves, deteriorates, or remains the same over time is uncertain. Methods— Thirty-five patients with ≥80% carotid artery stenosis or complete occlusion underwent CVC testing at baseline and 6 months later. CVC was assessed by measuring the increase in ipsilateral middle cerebral artery mean flow velocity in response to 5% inhaled CO2. Continuous tracings of left and right middle cerebral artery flow velocity, heart rate, respiratory rate, and Pco2 were recorded and then analyzed offline. One-way analysis of variance was used to compare baseline CVC in symptomatic and asymptomatic patients with control subjects. A paired t test was used to compare CVC before and after revascularization. Also, χ2 analysis was used to compar...

Combined stent placement and thrombolysis in acute vertebrobasilar ischemic stroke.

Abstract: BACKGROUND AND PURPOSE: Acute vertebrobasilar ischemic stroke is often associated with high morbidity and mortality with limited therapeutic options. Endovascular treatment with thrombolysis has offered some hope for affected patients; however, overall outcomes have been less than satisfactory. In this report, we present the results of our approach in six consecutive cases of acute vertebrobasilar ischemic stroke by combined proximal vessel stent placement and thrombolysis. METHODS: Six consecutive cases were retrospectively reviewed for the clinical outcome of patients presenting to our institution with acute posterior circulation stroke who underwent cerebral revascularization including proximal arterial stent placement by using balloon-expandable coronary stents and intraarterial thrombolysis. All of these patients were initially evaluated by stroke team neurologists and imaged with MR, including diffusion-weighted imaging documenting acute posterior circulation stroke. MR angiography of the circle of Willis was also obtained. Short-term follow-up was conducted to assess National Institutes of Health stroke scores (NIHSS) and modified Rankin scores. RESULTS: In these six cases, a combined approach of proximal arterial stent placement (five cases of vertebral artery origin and one case of carotid and subclavian stent placement plus vertebral artery revascularization) and thrombolysis was performed at variable times after stroke onset (range, 30 hours to 5 days). Four of the six patients had good basilar artery recanalization (Thrombolysis in Myocardial Infarction [TIMI] grade 0–1 before tissue plasminogen activator thrombolysis and TIMI grade 2 after procedure). Four of six patients had excellent immediate recovery and were discharged to an acute rehabilitation unit or their homes with improved neurologic symptoms and functional status. Two patients died: one patient presented with coma at outset with an NIHSS of 38, and the other patient probably had reocclusion of the basilar artery within 24 hours despite initial postprocedural improvement. CONCLUSION: We demonstrate that, in the setting of acute stroke, stent placement in combination with revascularization and thrombolysis is practical and allows quick access to a clot and simultaneously increases perfusion through collaterals during the thrombolytic process. In particular, basilar thrombolysis may be facilitated by proximal vertebral stent placement as concomitant atheromatous vertebrobasilar stenosis is common.

Early and late outcome after carotid artery bypass grafting with saphenous vein.

Abstract: Objectives This study was undertaken to determine outcome and durability of internal carotid artery bypass grafting with saphenous vein. Methods Data for 50 patients undergoing serial clinical and ultrasound surveillance were collected prospectively and analyzed retrospectively. Results Bypass grafting was performed in 50 patients between 1995 and 2002, the commonest reasons being excessive endarterectomy zone thinning or penetrating atheroma (n = 22), severe internal carotid artery coiling above the endarterectomy zone (n = 14), and patch infection (n = 5). Perioperative mortality was 2%, and death and stroke rate was 6%. Perioperative complications were associated with complex cardiovascular events, including hemorrhage after prosthetic patch infection, on-table thrombosis after endarterectomy, and synchronous carotid artery–cardiac reconstruction. One patient had a late ipsilateral stroke (10 months; normal scan). Cumulative stroke-free survival at 3 years (including operative events) was 91%. Cumulative freedom from recurrent stenosis greater than 70% or occlusion was 86% at 1 year and 83% at 3 years. Severe recurrent stenosis or occlusion developed in 7 patients, within 9 months of surgery in 6 patients and with 18 months in 1 patient. Angioplasty was performed without complication (no protection device, no stent) in 5 patients, 3 of whom required repeat angioplasty on at least one further occasion. Conclusions In common with venous conduits elsewhere, carotid artery bypass grafting with saphenous vein is associated with a high incidence of early graft stenosis. The long-term stroke risk, however, is low. Carotid artery bypass grafting is a safe and durable alternative when endarterectomy would prove hazardous or inadvisable, but regular surveillance is necessary.

Multiple intracranial arterial stenoses around the circle of Willis in association with Graves' disease: report of two cases.

Abstract: Objective and importance The association of Graves' disease with multiple intracranial arterial stenoses is rare. Clinical presentation We report on two Japanese women who experienced the concurrence of Graves' disease and cerebral ischemia attributable to multiple intracranial arterial stenoses around the circle of Willis. Clinically, these patients demonstrated hyperthyroidism, goiter, ophthalmopathy, and ensuing ischemic strokes. Cerebral angiography demonstrated multiple intracranial arterial stenoses around the circle of Willis in both cases. These cases did not meet the full diagnostic criteria for moyamoya disease, in that there were no abnormal, net-like, collateral vessels, but the other clinical and angiographic findings were consistent with this condition. Intervention After normalization of their hormonal conditions, the patients underwent cerebral revascularization procedures. Both patients achieved excellent recoveries and returned to normal daily life after treatment. Conclusion Multiple intracranial arterial stenoses and Graves' disease may occur simultaneously. Such cases may offer new insights into the pathogenesis of these two conditions. It is important to study more patients with this dual condition, to obtain more evidence of the relationship between genetic and immunogenic backgrounds.

Selective cerebral revascularization as an adjunct in the treatment of giant anterior circulation aneurysms.

Abstract: Cerebral revascularization, an indispensable component of neurovascular surgery, has been performed in the treatment of cranial base tumors, complex cerebral aneurysms, and occlusive cerebrovascular disease. The goal of a revascularization procedure is to augment blood flow distally. It can therefore be used as an adjunctive measure in the treatment of complex neurosurgical disease processes that require parent artery sacrifice for definitive treatment. In the treatment of giant anterior circulation aneurysms, for instance, a cerebral revascularization procedure may be considered in patients in whom the collateral circulation is marginal and in whom lesions may be treated either using a Hunterian-based strategy or clip-assisted reconstruction requiring a prolonged period of temporary occlusion. To date, there is no entirely effective method known to produce long-term tolerance to carotid artery (CA) sacrifice and, largely for that reason, some neurovascular surgeons advocate universal revascularization. The authors of this report, however, prefer to perform revascularization only in the limited subset of patients in whom preoperative assessment has revealed risk factors for cerebral ischemia due to hypoperfusion. In this paper, the authors introduce their protocol for assessing cerebrovascular reserve capacity, indications for cerebral revascularization in the treatment of complex anterior circulation aneurysms, and discuss their rationale for choosing to practice selective, rather than universal, revascularization.

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

Abstract: 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.

Evaluation of extracranial—intracranial arterial bypass function by using near-infrared spectroscopy

Abstract: Object. It has been reported that extracranial—intracranial (EC—IC) arterial bypass surgery can be useful in preventing stroke in patients with hemodynamic compromise. Little is yet known, however, regarding the extent to which the bypass contributes to maintaining adequate cerebral blood oxygenation (CBO) and its temporal changes following surgery. The authors evaluated bypass function repeatedly by using near-infrared spectroscopy (NIRS) after surgery. Methods. The authors investigated 30 patients who had undergone EC—IC bypass surgery. Single-photon emission computerized tomography revealed a decrease in regional cerebral blood flow (rCBF) and a lowered rCBF response to acetazolamide. Changes in CBO were evaluated in the sensorimotor cortex during compression of the anastomosed superficial temporal artery (STA). When decreases in oxyhemoglobin (HbO2) and total hemoglobin (Hb) concentrations were observed, the bypass was considered to have maintained CBO in the sensorimotor cortex given that decreases i...

Interpositional carotid artery bypass strategies in the surgical management of aneurysms and tumors of the skull base

Abstract: Cerebral revascularization is an important component in the surgical management of complex skull base tumors and aneurysms. Patients who harbor complex aneurysms that cannot be clipped directly and in whom parent vessel occlusion cannot be tolerated may require cerebrovascular bypass surgery. In cases in which skull base tumors encase the carotid artery (CA) and a resection is desired, a cerebrovascular bypass may be necessary in planned CA occlusion or sacrifice. In this review the authors discuss options for performing high-flow anterograde interposition CA bypass for lesions of the skull base. The authors review three important bypass techniques involving saphenous vein grafts: the cervical-to-petrous internal carotid artery (ICA), petrous-to-supraclinoid ICA, and cervical-to-supraclinoid ICA bypass. These revascularization techniques are important tools in the surgical treatment of complex aneurysms and tumors of the skull base and cavernous sinus.

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

Abstract: 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.

Ultrasonographically predicting the extent of collateral flow through superficial temporal artery-to-middle cerebral artery anastomosis

Abstract: BACKGROUND AND PURPOSE: This study was performed to elucidate whether the extent of bypass flow through superficial temporal artery-to-middle cerebral artery (STA-MCA) anastomosis could be indirectly estimated by measuring the blood flow velocity in the superficial temporal artery (STA) by using duplex ultrasonography. METHODS: We analyzed 29 patients (31 sides) who underwent STA-MCA bypass surgery for occlusive cerebrovascular disease (28 sides) or unclippable cerebral aneurysm that required therapeutic occlusion of the internal carotid artery (three sides). The flow velocities of the STA were measured by using ultrasonography. For patients who underwent the surgery unilaterally, the flow velocity ratios of the operated side to the contralateral side for the individual arteries were calculated. The correlation between these flow velocity parameters and the extent of bypass flow, which was graded based on the findings of cerebral angiography, was investigated. RESULTS: Both the affected STA flow velocity and the STA flow velocity ratio, particularly those in the end diastole, increased in patients with more extensive bypass flow. In patients with extensive, moderate, and poor bypass flow, the end diastolic flow velocities of the operated STA were 27.4 ± 8.8, 23.0 ± 7.8, and 13.5 ± 7.5 cm/s, respectively and the end diastolic flow velocity ratios of the STA were 3.4 ± 0.8, 2.1 ± 0.5 and 1.3 ± 0.4, respectively. The pulsatility index and resistance index of the affected STA were significantly lower in the patients with more extensive bypass flow. The optimal threshold value of the end diastolic flow velocity ratio of STA for the group with extensive bypass flow was 2.75, whereas that for the group with poor bypass flow was 1.60. With the obtained values, the sensitivity and specificity were 87.5% and 93.9% for the group with extensive bypass flow and 95.2% and 95.0% for the group with poor bypass flow, respectively. CONCLUSION: The blood flow velocity in the operated STA seems to be a highly sensitive parameter for predicting the extent of bypass flow in patients undergoing STA-MCA anastomosis.

Visualization of extracranial-intracranial bypass using multidetector-row helical computed tomography angiography.

Abstract: Purpose The advent of multidetector-row computed tomography (MDCT) has enabled images with good spatial resolution to be obtained over a wide range in a short scanning time. Our purpose was to determine whether CT angiography using the MDCT system could effectively depict extracranial-intracranial (EC-IC) bypass routes. Method Helical CT angiography was performed using an MDCT scanner in 12 patients who had undergone EC-IC bypass surgery: 10 patients had undergone superficial temporal artery-middle cerebral artery (MCA) anastomosis, 1 patient had undergone an encephaloduroarteriosynangiosis procedure for the treatment of moyamoya disease, and 1 patient had undergone an external carotid artery-MCA anastomosis using a graft. The resulting CT angiograms were visually evaluated for their depiction of the EC-IC bypass route. Conventional angiograms were available for comparison in all 12 patients. Results The EC-IC bypass was visualized to be patent at the site of anastomosis in all 12 patients. Branches of the MCA secondary or more to those connected to a donor artery were demonstrated in 9 patients, whereas MCA branches immediately distal to the anastomosis were demonstrated in 3 patients. The CT angiography findings corresponded well with the conventional angiography findings in all patients. Conclusion Helical CT angiography using the MDCT technique is an effective method for visualizing EC-IC bypass routes.

Nonpulsatile cerebral perfusion in Takayasu's arteritis.

Abstract: A nonpulsatile cerebral perfusion may be encountered in an artificial cardiopulmonary bypass used in cardiac surgery, which is exceptional in physiological conditions. The authors report on a 37-year-old woman with Takayasu's arteritis (TA) who had been suffering from progressive visual loss and recurrent seizures. Ocular findings of chronic ischemia and multiple, subcortical, high-signal lesions in magnetic resonance (MR) imaging were indicative of significant hemodynamic impairment. MR angiography showed the complete occlusion of the innominate artery, the left common carotid artery (CCA), and the subclavian artery from the orifice of the aortic arch. The patient's transcranial Doppler (TCD) waveform was flat throughout all segments of the intracranial arteries. Intravenous acetazolamide injection confirmed the severe impairment of vasoreactivity. After a bypass graft from the aorta to the left CCA, flow velocity and pulsatility were dramatically increased without postoperative complications. A nonpulsatile cerebral perfusion indicates severe hemodynamic impairment and is partially reversible by a surgical bypass graft. TCD seems to be useful to detect "high-risk" patients and to follow up in TA.

Thyrocervical trunk-external carotid artery bypass for positional cerebral ischemia due to common carotid artery occlusion. Report of three cases.

Abstract: Medically refractory positional cerebral ischemia and concomitant orthostatic hypotension associated with chronic common carotid artery (CCA) occlusion are rare. The authors detail their experience with three cases treated exclusively by an extracranial bypass in which the thyrocervical trunk was used as the donor vessel. Postoperatively grafts were patent and symptoms resolved in all three patients, although orthostatic hypotension remained. Postural cerebral ischemia due to CCA occlusion can be treated by extracranial bypass surgery. The thyrocervical trunk is a suitable donor for reconstruction of the external carotid artery in these cases.

Extracranial-intracranial bypass in cerebral ischemia.

Abstract: While the utility of extracranial-intracranial (EC-IC) bypass versus medical therapy for typical stroke indications was cast in doubt in the mid-1980s, EC-IC bypass has continued to be useful for maintaining cerebral circulation in specific cases. A case report demonstrates the utility of EC-IC bypass using PET and SPECT scanning technologies to assess cerebral hemodynamics. While further studies will better define the patient population, there is a subset of stroke patients that benefit from cerebral revascularization.

Axilloaxillary bypass for the treatment of subclavian artery stenosis complicated by bilateral common carotid artery occlusion: technical case report.

Abstract: OBJECTIVE AND IMPORTANCE: We successfully treated a patient with stenosis of the left subclavian artery, complicated by bilateral common carotid artery occlusion, via axilloaxillary bypass surgery. CLINICAL PRESENTATION: A 67-year-old patient with a history of hypertension and cerebral infarction underwent neck irradiation for treatment of a vocal cord tumor. Three months later, he began to experience transient tetraparesis several times per day. The blood pressure measurements for his right and left arms were different. Supratentorial blood flow was markedly low. The common carotid arteries were bilaterally occluded, and the right vertebral artery was hypoplastic. Therefore, only the left vertebral artery contributed to the patient's cerebral circulation; his left subclavian artery was severely stenotic. INTERVENTION: The patient underwent axilloaxillary bypass surgery because the procedure avoids thoracotomy or sternotomy, manipulation of the carotid artery, and interruption of the vertebral artery blood flow. The patient has been free of symptoms for more than 5 years. CONCLUSION: Neurosurgeons should be aware that extra-anatomic bypass surgery is an effective treatment option for selected patients with cerebral ischemia.

End-to-side anastomoses in small arteries with partial lateral clipping. An experimental study.

Abstract: The problem of total therapeutic occlusion of the cranial arteries remains a relatively important area of concern for neurosurgery, neurology, neuroradiology and neuroanesthesia as well as for the patients Cerebral revascularization procedures require total occlusion of the cranial arteries for a while End-to-side anastomoses with partial lateral clipping were done in 20 cadaver arteries and then, in one rat common carotid artery The results of the study were compared with the current cerebrovascular bypass procedures on a theoretical basis and possible clinical implications of the method were suggested All the anastomoses were found to be open As conclusions; 1) End-to-side anastomosis with partial lateral clipping and along with this technique the maintenance of blood flow in the target vessel during the anastomosis procedure are experimentally possible 2) Although the available aneurysm clips may be used in the bigger vessels (> 25 mm), currently, the exclusive clips for the technique are not available commercially 3) Further clinical implications of the technique may be investigated

Metabolic changes after revascularization in a patient with innominate artery occlusion by localized in vivo proton magnetic resonance spectroscopy.

Abstract: Localized in vivo proton magnetic resonance spectroscopy ((1)H-MRS) has been used to measure the metabolic status of the human brain in a non-invasive manner; thus, it is often called "a non-invasive biochemical assay". MRS is more sensitive than magnetic resonance imaging (MRI) in detecting ischemic damage by measuring the metabolic changes that occur prior to the anatomic changes. We report a patient who presented with innominate artery occlusion and symptoms of posterior circulation insufficiency and showed favorable metabolic changes by (1)H-MRS after revascularization. He showed no visible lesion in brain MRI, but in (1)H-MRS, decreased N-acetylaspartate (NAA) signal was noted in a resting state. After revascularization, both symptomatic improvement and recovery of NAA signal were observed. (1)H-MRS may provide valuable clinical information in diagnosis and management of cerebral hypoperfusion at a much earlier stage prior to the anatomic changes.

Cerebral Hemodynamics and Stroke Risk in Patients with Complete Carotid Artery Occlusion: Is There a Role for Cerebral Revascularization?

Abstract: Patients with complete carotid artery occlusion comprise approximately 15% of those with carotid territory transient ischemic attacks or infarction [1, 2, 3]. Prevention of subsequent stroke in patients with carotid artery occlusion remains a difficult challenge. The overall risk of subsequent stroke is 7% per year and the risk of stroke ipsilateral to the occluded carotid artery is 5.9% per year [4]. These risks persist in the face of platelet inhibitory drugs and anticoagulants [5]. The importance of hemodynamic factors in the prognosis of carotid occlusion and the role of surgical re-vascularization in the treatment of these patients has been a subject of controversy for many years. The technique of extracranial-intracranial (EC/IC) arterial bypass surgery was developed in the late 1960’s and applied to patients with carotid occlusion in an attempt to prevent subsequent stroke by improving the hemodynamic status of the cerebral circulation distal to the occluded vessel. The results of an international multicenter randomized trial to determine the efficacy of EC/IC arterial bypass for the prevention of subsequent stroke was reported in 1985. Among 808 patients with symptomatic carotid occlusion who were randomized, no benefit of superficial temporal artery — middle cerebral artery (STA-MCA) bypass surgery could be demonstrated [6]. Based on the results of this trial, EC/IC bypass was generally abandoned as a treatment for symptomatic carotid artery occlusion.