The endovascular management of intracranial vascular disease including the MERCI device

The prompt and aggressive management of acute stroke has become the standard of care as public awareness and the available successful treatment options both increase. The intravenous administration of tissue plasminogen activator within an established treatment window has been determined through large well-designed studies. The endovascular strategies for acute stroke have evolved significantly over the past 5 years and have been prompted by the limits of the intravenous treatment, as well as by the desire to demonstrate improved recanalization rates and improved long-term outcomes. Among these interventional treatment options are the intra-arterial administration of tissue plasminogen activator and newer antiplatelet agents, mechanical thrombectomy with the MERCI device, and intracranial angioplasty and stenting. This article outlines the major studies that have defined the current field of acute stroke management and discusses the basic treatment paradigms that are commonly utilized today.

Middle cerebral artery stenting for acute ischemic stroke after unsuccessful Merci retrieval

OBJECTIVE

Intracranial stenting has been used in the treatment of ischemic stroke caused by acute intracranial vessel occlusion after unsuccessful recanalization with the Merci retriever. We describe our early experience with this technique.

METHODS

Patients who had intra-arterial therapy for acute ischemic stroke with concomitant use of the retriever between February 1, 2005 and May 2, 2006 were identified from our endovascular database. Cases in which recanalization was not achieved with the retriever and in which stenting was attempted as a secondary means of mechanical recanalization were retrospectively reviewed.

RESULTS

Ten patients with unsuccessful Merci retrieval underwent intracranial stenting. The average admission National Institutes of Health Stroke Scale score was 16.4. Occlusions were located in the middle cerebral artery (six extended into M2 branches). Four patients received intra-arterial reteplase (two prestent, one preretriever and poststent, and one poststent). Eptifibatide was administered immediately before stenting in every patient. Successful recanalization (thrombolysis in myocardial infarction 2 or 3) was achieved in nine out of 10 patients. Complications included an extradural perforation with arteriovenous fistula. Six patients had intracranial hematoma and/or subarachnoid hemorrhage; there were four deaths. The six surviving patients experienced at least a 6-point National Institutes of Health Stroke Scale improvement at discharge, although only one had a modified Rankin Scale score of 2 or less.

CONCLUSION

Angiographic recanalization has been associated with improvement in clinical outcome after acute cerebral ischemia. Recanalization is not always achieved using the Merci retriever. We found that stenting after unsuccessful Merci retrieval resulted in a high rate of angiographic success. Further research into refining indications and optimizing outcome is warranted.

Mechanical thrombectomy with snare in patients with acute ischemic stroke

INTRODUCTION

We evaluated the efficacy and safety of thrombus extraction using a microsnare in patients with acute ischemic stroke (AIS).

METHODS

This was a prospective, observational, cohort study in which consecutive patients with AIS (<6 hours of ischemia for anterior circulation and <24 hours for posterior circulation) who had been previously excluded from intravenous tissue plasminogen activator (tPA) thrombolysis were included and followed-up for 3 months. Mechanical embolectomy with a microsnare of 2-4 mm was undertaken as the first treatment. Low-dose intraarterial thrombolysis or angioplasty was used if needed. TIMI grade and modified Rankin stroke scale (mRSS) score were used to evaluate vessel recanalization and clinical efficacy, respectively.

RESULTS

Nine patients (mean age 55 years, range 17-69 years) were included. Their basal mean NIHSS score was 16 (range 12-24). In seven out of the nine patients (77.8%) the clot was removed, giving a TIMI grade of 3 in four patients and TIMI grade 2 in three patients. Occlusion sites were: middle cerebral artery (four), basilar artery (two) and anterior cerebral artery plus middle cerebral artery (one). The mean time for recanalization from the start of the procedure was 50 min (range 50-75 min). At 3 months, the mRSS score was 0 in two patients and 3-4 in three patients (two patients died).

CONCLUSION

According to our results, the microsnare is a safe procedure for mechanical thrombectomy with a good recanalization rate. Further studies are required to determine the role of the microsnare in the treatment of AIS.

[Treatment of stroke in rats with bone marrow mesenchymal stem cells]

OBJECTIVE

To investigate the effects of treatment of stroke in rats with bone marrow mesenchymal stem cells (BMSCs) and mechanism thereof.

METHODS

Bone marrow of a healthy volunteer was collected and the BMSCs were separated with density gradient centrifugation. The hBMSC were cultivated and harvested until the third passage. A number of adult male Sprague-Dawley rats received corresponding behavioral training before surgery and underwent transient middle cerebral arterial occlusion (MCAO) for 2 hours. Sixty of them showing the scores of 6 approximately 12 according to the modified neurological severity score system were randomly divided into 2 groups: treatment group (n = 48, injected into the cortex around the ischemic areas with hBMSCs 3x10(5)/15 microl) and control group (n = 12, injected with D-Hanks solution 15 microl 24 hours after the establishment of MCAO models. Morris water maze test, Rotarod test and adhesive-removal test were performed since the 4th day to the 32 day after transplantation once every 3 days. 1, 2, 3, and 4 weeks after the transplantation 12 rats from each group were killed randomly to take out their brains. Immunofluorescence was used to identify the migration, survival and differentiation of the hBMSC.

RESULTS

A large number of hBMSC could be seen within 2 weeks after transplantation. The number of hBMSC decreased since the 21st day after transplantation and few cells could be found at the end of 1 month after. No definite evidence supported the differentiation of neural cells derived from the hBMSCs during the whole process. Morris water maze test showed that the mean escape time 1 week after transplantation of the treatment group was (69 +/- 10) s, significantly shorter than that of the control group [(120 +/- 0) s, P < 0.05] The significant difference persisted until the 4(th) week (P > 0.05). Rotarod test with the speed of 10 r/min showed that the mean latency period 10 days after transplantation of the treatment group was (167 +/- 18) s, significantly longer than that of the control group [(37 +/- 19) s, P < 0.05]. The significant difference persisted until the experimental terminal. The adhesive-removal test showed that the mean latency period 13 days after transplantation of the treatment group was (33 +/- 8) s, significant shorter than that of the control group [(84 +/- 13) s, P < 0.05]. The significant difference persisted until the experimental terminal.

CONCLUSION

Injection of hBMSCs into brain cortex improves neurological functional recovery after stroke. The transplanted cells can migrate and survive for a certain period, but no hBMSC express proteins phenotype of neural cells.

[Stepwise surgical treatment in patients with multiple stenotic and occlusive lesions of the great arteries of the brain]

The study was conducted at the Academician N. N. Burdenko Institute of Neurosurgery, Moscow, in 1999 to 2006. The paper presents the results of stepwise surgical treatment in 84 patients with chronic cerebral ischemia, caused by multiple stenotic and occlusive lesions of the brachiocephalic arteries, who underwent 183 reparative operations. Six major groups of patients with various combinations of lesions of major cerebral arteries were identified. An attempt was made to create an algorithm of the optimum stepwise surgical treatment policy in the identified groups of patients on the basis of the site, degree, and nature of stenotic lesions, by taking into account the cerebral hemodynamics and collateral circulation at all stages of surgical treatment. At the same time, changes in the degree of neurological deficit as one of the major determinants of the results of surgical treatment could be evaluated. The study has demonstrated that the chosen tactics of employing series arterial reconstructions in multiple stenotic and occlusive lesions of major cerebral arteries is an effective treatment option in patients with chronic cerebral ischemia.

Selective neuronal damage and chronic hemodynamic cerebral ischemia

OBJECTIVE

In atherothrombotic internal carotid artery or middle cerebral artery (MCA) occlusive disease, chronic hemodynamic compromise may increase the risk for cerebral ischemic damage. To determine whether selective neuronal damage demonstrated as a decrease in central benzodiazepine receptor (BZR) in the normal-appearing cerebral cortex is associated with increased oxygen extraction fraction (OEF) (misery perfusion).

METHODS

We measured BZR and OEF using positron emission tomography in 105 nondisabled patients with atherothrombotic internal carotid artery or MCA occlusive disease and no cortical infarction. By using three-dimensional stereotactic surface projections and the stereotactic extraction estimation method, without correction for partial volume effects, the abnormally decreased BZR index [(the extent of the pixels with Z-score more than 2 compared with controls) x (average Z-score in those pixels)] in the cerebral cortex of the MCA distribution with arterial disease was calculated, and it was found to be correlated with the mean hemispheric value of OEF and several clinical variables.

RESULTS

All patients had pixels with abnormally decreased BZR, with the extent varying from 0.04 to 60.91%. Multivariate analysis showed that the abnormally decreased BZR index was positively correlated with the value of OEF and the history of stroke, whereas it was negatively correlated with the presence of hypercholesterolemia with statin treatment. Follow-up examinations of 17 patients without ischemic episode showed that a decrease of BZR was associated with an increase of OEF.

INTERPRETATION

In atherothrombotic internal carotid artery or MCA occlusive disease, misery perfusion may cause selective neuronal damage, and statins might have beneficial effects against neuronal damage.

[Indications for using an intraluminal temporary bypass in operations on carotid arteries]

The review is dedicated to the most commonly used method of protecting the brain in carotid endarterectomy, i. e. using an intraluminal temporary bypass (ITB), also containing the information concerning the constructions of ITBs, various points of view regarding practical application thereof, as well as the methods of monitoring the functions of the brain in order to solve the problem concerning feasibility of using an ITB.

Mechanical Thrombectomy for Acute Ischemic Stroke

Background and Purpose— Mechanical thrombectomy is a promising new modality of interventional stroke treatment. The various devices differ with regard to where they apply force on the thrombus, taking a proximal approach such as aspiration devices or a distal approach such as basket-like devices. The study compares the in vivo effectiveness and thrombus–device interaction of these 2 approaches.

Methods— Angiography and embolization with a radioopaque whole blood thrombus was performed in 10 swine. Mechanical thrombectomy was performed in 20 cranial vessels using a proximal aspiration device (Vasco35) and a distal basket-like device (Catch) with and without proximal balloon occlusion. Fifty-six retrieval attempts were made.

Results— The proximal device allowed fast repeated application with a low risk of thromboembolic events (3%) and vasospasm, but it had a significantly lower success rate (39.4%) in retrieving thrombotic material than the distal device (DD) (82.6%; odds ratio, 7.3; 95% CI, 2.0 to 26.4). The compaction of the thrombus during retrieval with DD increased the risk of vessel wall irritation significantly ( P <0.01) and complicated retrieval into the guiding catheter. The number of embolic events was significantly higher with DD (26%; odds ratio, 11.3; 95% CI, 1.35 to 101.6) unless proximal balloon occlusion was used.

Conclusions— The proximal and the distal approaches to mechanical thrombectomy proved to be effective at achieving recanalization of cranial vessels. The proximal device is faster in application and allowed repeated attempts with a low complication rate. The DD is more successful at removing thrombotic material, but its method of application and attendant thrombus compaction increase the risk of thromboembolic events and vasospasms.

Multiple bur hole surgery for the treatment of moyamoya disease in children

OBJECT

The authors' aim in this study was to review their experience in the use of indirect revascularization alone in a series of 14 children with moyamoya disease, in which numerous bur holes and arachnoid openings were made over each affected hemisphere.

METHODS

Revascularization through multiple bur holes and arachnoid openings was performed in 14 children (mean age at diagnosis 6.5 years [range 3-15 years]) who suffered from progressive moyamoya disease. The authors performed surgery in a total of 24 hemispheres during 18 procedures. Ten children underwent bilateral multiple bur hole procedures, three underwent a unilateral procedure in the more severely affected hemisphere, and one child had previously undergone an encephaloduroarteriomyosynangiosis on the contralateral side. Ten to 24 bur holes were made in the frontotemporoparietooccipital area of each hemisphere, depending on the site and extent of the disease. Early postoperative perfusion magnetic resonance imaging studies, performed in the five most recent cases, showed restoration of cortical perfusion as early as 3 months, which was confirmed on subsequent angiography studies (performed between 8 and 12 months postoperatively) that showed excellent revascularization of the ischemic brain by external carotid artery collateral vessels. None of the children sustained further ischemic attacks postoperatively. Motor improvement was noted in those who had presented with paresis. A single seizure episode occurred in two patients at 2 weeks and 5 months after surgery; both children had presented with epilepsy. There were no postoperative deaths, and only one complication (an infected lumbar shunt in the patient who required cerebrospinal fluid [CSF] drainage). Five of the 18 procedures were complicated by subcutaneous CSF collections, which resolved with tapping and compressive head dressings; a transient lumbar drain was necessary in one case.

CONCLUSIONS

The results obtained in this series suggest that in children with moyamoya disease this simple technique is both effective and safe. Furthermore, it is effective as a sole treatment without supplementary revascularization procedures.

Carotid angioplasty and stenting: caveat emptor!

Carotid endarterectomy effectively reduces stroke in patients with TIA or minor stroke and a high-grade carotid stenosis. Carotid endarterectomy is also beneficial in male asymptomatic patients younger than 75 years with high-grade stenosis. Carotid stenting has not been as thoroughly evaluated as carotid endarterectomy in randomized trials. The few trials that have been performed up to now show either inferior results or suggest equivalence. Before accepting carotid stenting as a mainstream treatment for carotid stenosis, this therapy should be as critically evaluated as carotid endarterectomy was in the 1980s and 1990s.

Symptomatic non-atherosclerotic bilateral extracranial vertebral artery occlusion treated with extracranial to intracranial bypass: case report

Posterior fossa ischemia is not a very frequent situation. It is responsible for about 25% of all ischemic strokes, and the vast majority of the cases are related to atherosclerotic stenosis of the vertebral and/or basilar arteries. Acute ischemia can also occur in the setting of vertebral artery dissection, traumatic or spontaneous. Recently, blunt trauma has been increasingly recognized as a cause for craniocervical artery injury. The management options for both traumatic and atherosclerotic lesions of the posterior fossa are still under debate. We present a case of a delayed onset of hemodynamic ischemic symptoms due to bilateral vertebral artery occlusion probably related to remote trauma to the head and neck in a 55-year-old-man treated successfully with extracranial to intracranial bypass.

Granulocyte-colony-stimulating factor mobilizes bone marrow stem cells in patients with subacute ischemic stroke: the Stem cell Trial of recovery EnhanceMent after Stroke (STEMS) pilot randomized, controlled trial (ISRCTN 16784092)

BACKGROUND AND PURPOSE

Loss of motor function is common after stroke and leads to significant chronic disability. Stem cells are capable of self-renewal and of differentiating into multiple cell types, including neurones, glia, and vascular cells. We assessed the safety of granulocyte-colony-stimulating factor (G-CSF) after stroke and its effect on circulating CD34+ stem cells.

METHODS

We performed a 2-center, dose-escalation, double-blind, randomized, placebo-controlled pilot trial (ISRCTN 16784092) of G-CSF (6 blocks of 1 to 10 microg/kg SC, 1 or 5 daily doses) in 36 patients with recent ischemic stroke. Circulating CD34+ stem cells were measured by flow cytometry; blood counts and measures of safety and functional outcome were also monitored. All measures were made blinded to treatment.

RESULTS

Thirty-six patients, whose mean+/-SD age was 76+/-8 years and of whom 50% were male, were recruited. G-CSF (5 days of 10 microg/kg) increased CD34+ count in a dose-dependent manner, from 2.5 to 37.7 at day 5 (area under curve, P=0.005). A dose-dependent rise in white cell count (P<0.001) was also seen. There was no difference between treatment groups in the number of patients with serious adverse events: G-CSF, 7/24 (29%) versus placebo 3/12 (25%), or in their dependence (modified Rankin Scale, median 4, interquartile range, 3 to 5) at 90 days.

CONCLUSIONS

G-CSF is effective at mobilizing bone marrow CD34+ stem cells in patients with recent ischemic stroke. Administration is feasible and appears to be safe and well tolerated. The fate of mobilized cells and their effect on functional outcome remain to be determined.

Vascular fate of adipose tissue-derived adult stromal cells in the ischemic murine brain: A combined imaging-histological study

Increasing evidence indicates that fat tissue can provide a novel source of progenitor cells with therapeutic potential. Here, the fate of adipose tissue-derived stromal cells (ADSCs) transplanted into the mouse ischemic cortex was monitored in the long term using in vivo imaging, and subsequently characterized. The left middle cerebral artery (MCA) was occluded in C57BL/6J mice equipped with a closed cranial window chronically implanted over the left parietal cortex (n = 20). ADSCs expressing the green fluorescent protein (GFP) (approximately 18 x 10(3) cells in 0.5 microl) were transplanted into the ipsilateral cortex, 24 h after MCA occlusion. GFP+-ADSCs were monitored through the window using confocal fluorescence microscopy to assess their single fate in vivo. Co-localization of GFP with vascular, neuronal, glial or proliferation markers was investigated immunohistochemically. Repeated in vivo imaging revealed that GFP+-ADSCs migrated over 1 week toward the lesion, survived for at least 4 weeks, and exhibited a particular tropism for vessels. About 5% of the transplanted GFP+-ADSCs were scattered in the peri-ischemic area on histological sections. Immunohistochemistry evidenced that perivascular GFP+-ADSCs enfolded CD31-labeled endothelial cells, always outside their basal lamina, and occasionally expressed smooth muscle alpha-actin. Less than 1% GFP and BrdU co-labeling indicated a low proliferation rate of ADSCs. These results demonstrate that cerebral ischemia induces ADSCs survival, migration toward the lesion, especially toward microvessels, and occasional differentiation into smooth muscle cells.

p53 potentiates hippocampal neuronal death caused by global ischemia

Although p53 controls cell death after various stresses, its role in neuronal death after brain ischemia is poorly understood. To address this issue, we subjected p53-deficient (p53-/- and p53+/-) mice (backcrossed for 12 generations with C57BL/6 mice) and wild-type mice (p53+/+) to transient global ischemia by the three-vessel occlusion method. Despite similar severity of ischemia, as shown by anoxic depolarization and cortical blood flow, neuronal death in the hippocampal cornus ammonis (CA)1 region was much more extensive in p53+/+ than in p53-/- mice (surviving neuronal count, 9.3%+/-3.0% versus 61.3%+/-34.0% of nonischemic p53+/+ controls, respectively, P<0.0037). In p53+/- mice, a similar trend was also observed, though not statistically significant (43.5% of nonischemic p53+/+ controls). In p53+/+ mice, p53-like immunoreactivity in hippocampal CA1 neurons was enhanced at 12 h after ischemia, and messenger ribonucleic acid for Bax, a direct downstream target of p53, was also increased. These results indicate that p53 potentiates ischemic neuronal death in vivo and suggest that this molecule could be a therapeutic target in neuronal death after cerebral ischemia.

Hemichorea due to hemodynamic ischemia associated with extracranial carotid artery stenosis. Report of two cases

In this paper the authors describe two patients with recurrent hemiparesis and limb shaking that gradually progressed to hemichorea. Cerebral angiography confirmed severe unilateral internal carotid artery stenosis (95%) contralateral to the hemichorea. The cerebral blood flow, assessed using N-isopropyl-p-(iodine-123) iodoamphetamine single-photon emission computed tomography (SPECT), disclosed markedly decreased vascular reserves in both patients. After carotid endarterectomy was performed, the hemichorea gradually subsided and SPECT confirmed increased cerebral perfusion. The results in these cases indicate that surgical revascularization is effective for hemichorea due to cerebral ischemia with reduced vascular reserve.

Stepwise revascularization for prevention of postoperative hyperperfusion

Abrupt normalization of cerebral blood flow (CBF) after surgical procedures to improve excessive cerebral hypoperfusion can cause irreversible brain parenchymal damage. Such hyperperfusion, which is caused by inflow at normal blood pressure into maximally dilated fine vessels, is an important complication following carotid endarterectomy (CEA). Strict control of blood pressure in the perioperative period can prevent this complication except in a few patients, who have severe cerebral hypoperfusion and poor cerebrovascular reserve due to extremely severe stenosis of the ipsilateral or the bilateral carotid arteries, for which CEA is indicated. The requirement for improved CBF and the risk of postoperative hyperperfusion conflict in the pathogenesis of these patients. We tried to prevent abrupt improvement in perfusion by attempting gradual restoration of CBF. Superficial temporal artery-middle cerebral artery anastomosis was first performed to improve the poor cerebrovascular reserve by allowing insufficient blood flow. A few weeks later, CEA was performed to completely restore CBF. This surgical approach obtained good results without postoperative problems in four patients. The indications of this surgical management and efficacy of stepwise restoration of CBF to prevent postoperative hyperperfusion depend on careful preoperative evaluation of perfusion studies.

Early Carotid Endarterectomy after Ischemic Stroke: The Results of a Prospective Multicenter Italian Study

OBJECTIVES

To evaluate safety of early carotid endarterectomy (CEA) in patients with acute brain ischemia presenting to the emergency department stroke units (EDSU).

METHODS

The neurologists, neuroradiologists and vascular surgeons on duty in emergency departments enrolled 96 patients who underwent very early CEA according to a predefined protocol within two years. The protocol included evaluation of neurological status by National Institute of Health Stroke Scale (NIHSS), neuroimaging assessment, ultrasound of the carotid arteries and Transcranial Doppler. Patients with NIHSS>22 or whose neuroimaging showed brain infarct >2/3 of the middle cerebral artery territory were excluded. All eligible patients underwent CEA as soon as possible. Primary end points of the study were mortality, neurological morbidity by NIHSS and postoperative hemorrhagic conversion on neuroimaging. Statistical analysis was performed by univariate analysis.

RESULTS

The mean time elapsing between the onset of stroke and endarterectomy was 1.5 days (+/-2 days). The overall 30-day morbidity mortality rate was 7.3% (7/96). No neurological mortality occurred. On hospital discharge, three patients (3%) experienced worsening of the neurological deficit (NIHSS score 1 to 2, 1 to 3 and 9 to 10 respectively). Postoperative CT demonstrated there were no new cerebral infarcts nor hemorrhagic transformation. At hospital discharge 9/96 patients (9%) had no improvement in NHISS scores, 37 were asymptomatic and 45 showed a median decrease of 4.5 NIHSS points (range 1-18). By univariate analysis none of the considered variables influenced the clinical outcome.

CONCLUSION

Our protocol selected patients who can safely undergo very early (<1.5 days) surgery after acute brain ischemia. Large randomized multicenter prospective trials are warranted to compare very early CEA versus best medical therapy.

Administration of Ex Vivo-expanded Bone Marrow-derived Endothelial Progenitor Cells Attenuates Focal Cerebral Ischemia-reperfusion Injury in Rats

OBJECTIVE

This study aimed to examine early effects of ex vivo-expanded bone marrow-derived endothelial progenitor cells (EPCs) on focal cerebral ischemia-reperfusion injury.

METHODS

EPCs were obtained from mononuclear cells of autologous bone marrow of a rat. After culture on fibronectin-coated dishes for 10 to 14 days, 2.5 x 10 cells of EPCs were administered transarterially after 90 minute occlusion of the middle cerebral artery.

RESULTS

Administration of EPCs significantly reduced both the infarct volume and the scores of neurological deficits at 24 and 48 hours. EPCs administered 2 hours after insult did not reduce infarct volume, but attenuated neurological deficits at 24 hours. Administration of EPCs significantly reduced the number of myeloperoxidase-immunoreactive cells in the ischemic lesion at 24 hours and increased regional cortical blood flow at 48 hours. EPCs were observed in the ischemic hemisphere and around the endothelial layer of the pial arteries. Most of them expressed endothelial nitric oxide synthase.

CONCLUSION

Administration of ex vivo-expanded bone marrow-derived EPCs reduced infarct volume and neurological deficits in acute focal brain ischemia-reperfusion injury caused, at least in part, by attenuation of endothelial dysfunction.

Neuroprotection by PlGF gene-modified human mesenchymal stem cells after cerebral ischaemia

Intravenous delivery of mesenchymal stem cells (MSCs) prepared from adult bone marrow reduces infarction size and ameliorates functional deficits in rat cerebral ischaemia models. Placental growth factor (PlGF) is angiogenic to impaired non-neural tissue. To test the hypothesis that PlGF contributes to the therapeutic benefits of MSC delivery in cerebral ischaemia, we compared the efficacy of systemic delivery of human MSCs (hMSCs) and hMSCs transfected with a fibre-mutant F/RGD adenovirus vector with a PlGF gene (PlGF-hMSCs). A permanent middle cerebral artery occlusion (MCAO) was induced by intraluminal vascular occlusion with a microfilament. hMSCs and PlGF-hMSCs were intravenously injected into the rats 3 h after MCAO. Lesion size was assessed at 3 and 6 h, and 1, 3, 4 and 7 days using MR imaging and histology. Functional outcome was assessed using the limb placement test and the treadmill stress test. Both hMSCs and PlGF-hMSCs reduced lesion volume, induced angiogenesis and elicited functional improvement compared with the control sham group, but the effect was greater in the PlGF-hMSC group. Enzyme-linked immunosorbent assay of the infarcted hemisphere revealed an increase in PlGF in both hMSC groups, but a greater increase in the PlGF-hMSC group. These data support the hypothesis that PlGF contributes to neuroprotection and angiogenesis in cerebral ischaemia, and cellular delivery of PlGF to the brain can be achieved by intravenous delivery of hMSCs.

Magnetic resonance angiography and clinical evaluation of third nerve palsies and posterior communicating artery aneurysms

Object

The authors conducted a study to determine the utility of the clinical profile and magnetic resonance (MR) angiography in evaluating patients with isolated third cranial nerve palsies or posterior communicating artery (PCoA) aneurysms.

Methods

Three-dimensional time-of-flight MR angiography was performed in a consecutive series of patients with isolated acute third cranial nerve palsy not due to a ruptured aneurysm and in patients with unruptured PCoA aneurysms. A neuroradiologist, masked to the identities of the patients, interpreted reformatted maximum intensity projection (MIP) and source images of the PCoAs and aneurysms. The investigators assessed clinical features of oculomotor nerve dysfunction and focal head pain. Cases involving cranial third nerve palsy without aneurysms were classified as Group 1 (no case entailed catheter-based angiography), and cases involving PCoA aneurysms seen on MR angiography (42 cases confirmed by catheter-based angiography) were classified as Group 2.

The mean age of the 73 patients in Group 1 was 60.1 years and that of the 45 patients in Group 2 was 59.1 years (p = 0.37). The pattern and severity of oculomotor (p = 0.61) and lid (p = 0.83) dysfunction and pain frequency (p = 0.2) were similar for the 73 patients with vasculopathy in Group 1 and the 15 symptomatic patients in Group 2. Abnormal pupils were observed in 38% of the patients in Group 1 and 80% of those in Group 2 (p = 0.016). In cases of complete external third nerve palsy, nine of 22 in Group 1 and none of four in Group 2 had normal pupil function. For all patients, source imaging showed 206 PCoAs (85%) and MIP imaging demonstrated 120 PCoAs (49%). Of 48 aneurysms (three bilateral), MIP imaging showed 44 (92%) and source imaging showed 47 (98%). Only a 2-mm aneurysm seen on catheter-based angiography was missed by MR angiography. Symptomatic aneurysms were equal or greater than 4 mm in size.

Conclusions

Only the presence of complete external third nerve palsy and normal pupil function allowed ischemia to be clinically distinguished from a PCoA aneurysm in a patient with isolated third nerve palsy and no subarachnoid hemorrhage. When source image MR angiography demonstrates normal findings, catheter-based angiography need not be performed in these patients, even if pupil function is abnormal.

Changes in Brain Volume 2 Years after Extracranial-Intracranial Bypass Surgery: A Preliminary Subanalysis of the Japanese EC-IC Trial

BACKGROUND AND METHODS

We studied changes in brain volume on magnetic resonance imaging in 10 patients with and without extracranial-intracranial (EC-IC) bypass surgery who met the inclusion criteria for the Japanese EC-IC Bypass Trial, a multicenter, randomized, prospective study of patients with hemodynamic brain ischemia due to cerebral artery occlusive disease. We also examined the association of cerebral hemodynamics on single-photon emission computed tomography with the changes in brain volume.

RESULTS

The affected/unaffected ratio of the percent brain volume declined in patients without EC-IC bypass surgery (p < 0.02, n = 4), and the affected/unaffected percent regional cerebral blood flow ratio increased in patients with the surgery (p < 0.03, n = 6). Acetazolamide reactivity increased in the affected hemisphere of patients with surgery (p < 0.01). Two-year increase (decrease) in acetazolamide reactivity of the affected hemisphere showed a significant positive correlation with 2-year changes in the affected/unaffected percent brain volume ratio (R2 = 0.737, p = 0.0007).

CONCLUSIONS

Change in acetazolamide reactivity might be a good predictor for brain atrophy in cerebral artery occlusive disease.

Cerebral hyperperfusion after carotid endarterectomy is associated with preoperative hemodynamic impairment and intraoperative cerebral ischemia

The aim of this study was to investigate whether postoperative hyperperfusion is associated with preoperative cerebral hemodynamic impairment due to chronic ischemia and with acute cerebral ischemia during clamping of the internal carotid artery (ICA) during carotid endarterectomy (CEA). Transcranial cerebral oxygen saturation (SO2) was monitored intraoperatively using near-infrared spectroscopy in 89 patients undergoing CEA for ipsilateral ICA stenosis (>70%). Cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to acetazolamide were also measured using single photon emission computed tomography (SPECT) before CEA. In addition, CBF was measured immediately after CEA and on the third postoperative day. Hyperperfusion (CBF increase>100% compared with preoperative values) was observed immediately after CEA in 10 of 18 patients (56%) with reduced preoperative CVR. Also, post-CEA hyperperfusion was observed in nine of 16 patients (56%) whose SO2 during clamping of the ICA decreased to less than 90% of the preclamping value. Logistic regression analysis showed that reduced preoperative CVR and reduced SO2 during ICA clamping were significant independent predictors of the development of hyperperfusion immediately after CEA. In fact, all patients with reduced preoperative CVR and reduced SO2 during ICA clamping developed post-CEA hyperperfusion, and two of these patients developed cerebral hyperperfusion syndrome. These data suggest that development of cerebral hyperperfusion after CEA is associated with preoperative hemodynamic impairment and intraoperative cerebral ischemia.

[Surgical treatment of the brain ischemic disease]

There were examined 825 patients, in whom affection of extracranial arteries was revealed, including 340 (41.2%) men and 485 (58.8%) women, 27 to 73 years old. Atherosclerotic stenosis and occlusion of extracranial arteries was diagnosed in 305 (40.0%), pathologic kinking of vessels on atherosclerosis and hypertonic disease background--in 196 (23.8%), pathological kinking, caused by aortoarteriitis and fibrose--muscular displasia--in 197 (23.9%), hypoplasia of arteries--in 54 (6.5%), aortoarteriitis--in 73 (8.8%) patients. Stages I-IV ischemia together with proven affection of extracranial arteries served as indication for surgical treatment of chronic cerebro-vascular insufficiency. Depending on character of the arteries affection 11 kinds of operative interventions were conducted, using complex intraoperative program of the brain defense. Total number of reconstructive operations performed was 967. In 752 (91.2%) patients immediate good and satisfactory results were noted. In the late period 450 patients were examined: good results were achieved in 64.9%, satisfactory--in 22%, in 30 (6.7%) improvement did not occur and 28 (6.2%) died. Introduction of the proposed complex examination and surgical treatment program have permitted to improve the results of treatment of the patients, suffering chronic brain ischemia.