Indications for carotid endarterectomy.
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Carotid Stenosis↗
Biomedical subjects
F B Meyer
Publications and source records attributed to F B Meyer.
Treatment with basic fibroblastic growth factor following focal cerebral ischemia does not prevent neuronal injury.
This experiment determined if postischemic administration of basic fibroblast growth factor (bFGF) would result in neovascularization to minimize neuronal injury following a focal cerebral ischemia insult. Fifty-eight Sprague-Dawley rats underwent middle cerebral artery (MCA) occlusion and were divided into three groups receiving either vehicle, serum, or 50 ng bFGF biweekly through an indwelling ventricular cannula. At variable time intervals, the animals underwent carbon black perfusion of capillary beds and histological staining for assessment of neuronal injury. Following MCA occlusion, there was a significant decrease in capillary bed density in peri-infarction cortex which normalized by two weeks. The number of alive neurons in the peri-infarction cortex was also significantly decreased compared to contralateral control cortex. The chronic administration of bFGF commencing two days after MCA occlusion did not result in either a significant increase in capillary bed density or the number of alive neurons in the peri-infarction cortex.
Animals↗
Effects of intermittent reperfusion on brain pHi, rCBF, and NADH during rabbit focal cerebral ischemia.
BACKGROUND AND PURPOSE: The use of intermittent reperfusion versus straight occlusion during neurovascular procedures is controversial. This experiment studied the effects of intermittent reperfusion and single occlusion on intracellular brain pH (pHi), regional cerebral or cortical blood flow, and nicotinamide adenine dinucleotide (NADH) fluorescence during temporary focal ischemia. METHODS: Twenty fasted rabbits under 1.0% halothane anesthesia were divided into four groups: (1) nonischemic controls, (2) 60 minutes of uninterrupted focal ischemia, (3) 2 x 30-minute periods of focal ischemia separated by a 5-minute reperfusion, and (4) 4 x 15-minute periods of focal ischemia separated by three 5-minute reperfusion periods. Focal ischemia was produced by occlusion of both the middle cerebral and ipsilateral anterior cerebral arteries. After the final occlusion, there was a 3-hour reperfusion period in all groups. Regional cerebral and cortical blood flow, brain pHi, and NADH fluorescence were measured with in vivo panoramic fluorescence imaging. RESULTS: During occlusion, regional cerebral and cortical blood flows and NADH fluorescence values were not different among the groups. Brain pHi was significantly lower in the 4 x 15-minute group compared with the 1 x 60-minute group (6.57 +/- 0.02 versus 6.73 +/- 0.06; P < .03) but not significant when compared with the 2 x 30-minute group. During the short reperfusion periods, all parameters returned to normal except for NADH fluorescence levels, which remained elevated. During the postischemic final reperfusion period, there was a mild brain alkalosis of approximately 7.1 in all groups. There were no significant differences in NADH fluorescence among groups during the final reperfusion. Regional cerebral and cortical blood flow returned to near normal values in all groups. CONCLUSIONS: This study demonstrates that intermittent reperfusion during temporary focal ischemia has different effects on the intracytoplasmic and the intramitochondrial compartments: worsening of brain cytoplasmic pHi but no significant differences in the oxidation/reduction level of mitochondrial NADH.
Animals↗
Childhood dural arteriovenous fistulae of the posterior dural sinuses: three case reports and literature review.
We report three cases of posterior dural sinus arteriovenous fistulae in pediatric patients and a literature review of 18 additional cases. These lesions carry a grave prognosis with a reported mortality of 38% and with an historical anatomic cure of only approximately 9%. With advanced neurointerventional techniques and increased knowledge of their pathophysiology, these highly complicated lesions can be more safely treated with a strategy that involves extensive preoperative embolization and surgical excision. The importance of delaying direct surgery with conservative measures or interventional radiological treatment, including preoperative transarterial and transvenous embolization, is critical in the management of these lesions.
Cerebral Angiography↗
Seasons, snow, and subarachnoid hemorrhage: lack of association in Rochester, Minnesota.
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Aneurysm, Ruptured↗
Effect of intermittent reperfusion and nitric oxide synthase inhibition on infarct volume during reversible focal cerebral ischemia.
The authors examined the effects of both intermittent reperfusion and nitric oxide synthase (NOS) inhibition, caused by NG-nitro-L-arginine methyl ester (L-NAME) during episodes of focal cerebral ischemia induced to simulate the neurosurgical setting. Seventy-eight Wistar rats underwent single (60 minutes of ischemia) or repetitive (four 15-minute periods of ischemia separated by 5 minutes of reperfusion) episodes of middle cerebral artery occlusion while under anesthesia (1.0% halothane). Twenty-four hours after the procedure, the animals were given neurological examinations and then sacrificed for histological preparation and examination. The intermittent reperfusion groups tended to have smaller mean cortical infarctions. There was also a trend showing a decrease in infarction size in groups given L-NAME. The combination of intermittent reperfusion and preischemic administration of L-NAME (10 mg/kg) resulted in a 65% reduction in infarction size (p < 0.05) when compared to that caused by 60 minutes of single occlusion without L-NAME. The use of NOS inhibition combined with intermittent reperfusion may be a technique to provide intraoperative cerebral protection during neurovascular procedures that require temporary vascular occlusion.
Analysis of Variance↗
Medical and surgical management of intracranial aneurysms.
OBJECTIVE: To examine the medical and surgical aspects of intracranial aneurysms, including the pathogenesis, clinical manifestations, management of subarachnoid hemorrhage (SAH), and indications for surgical intervention. DESIGN: This review presents the classification of intracranial aneurysms, defines specific aneurysms, and analyzes the Mayo Clinic experience with surgical treatment of cerebral aneurysms. MATERIAL AND METHODS: Intracranial aneurysms are classified by cause, size, site, and shape. The clinical grading systems for SAH, the most common manifestation, are as follows: modified Botterell, Hunt and Hess, and World Federation of Neurological Surgeons. Surgical options are direct clipping, interventional neuroradiologic treatment, proximal ligation or trapping of aneurysms, and wrapping or coating of aneurysms. Although the timing of surgical intervention after SAH is controversial, it should be based on the clinical grade, site of the aneurysm, and patient's medical condition. RESULTS: The frequency of intracranial aneurysms is estimated to be 1 to 8% in the general population, and 90% of patients have SAH. After SAH, 8 to 60% of patients die before they get to a hospital. After hospitalization, the mortality rate is 37%, severe disability is 17%, and outcome is favorable in 47%. The current trend for surgical treatment is early after SAH. The Mayo Clinic experience with 1,947 patients who underwent surgical treatment because of aneurysmal SAH or for aneurysmal repair between 1969 and 1990 is as follows: 1,445 had an excellent outcome, 231 had a good outcome, 171 had a poor outcome, and 100 died. CONCLUSION: Aggressive management can be beneficial for many patients with severe neurologic injury after SAH by preventing rerupture of the aneurysm, attenuating the severity and sequelae of vasospasm, and decreasing the surgical complications.
Aged↗
Cortical petechial hemorrhage, leukoencephalopathy, and subacute dementia associated with seizures due to cerebral amyloid angiopathy.
Although cerebral amyloid angiopathy is a well-known cause of cerebral lobar hemorrhage, subacute dementia, seizures, and acute encephalopathy without lobar hemorrhage are infrequently recognized as manifestations of this disease. In this report, we describe a case of cerebral amyloid angiopathy in a 74-year-old woman who had subacute progressive dementia and a superimposed rapid acute neurologic deterioration associated with seizures and the presence of cerebral edema on computed tomographic scans and leukoencephalopathy and cortical petechial hemorrhages on magnetic resonance imaging. A diagnosis of cerebral amyloid angiopathy in conjunction with small cortical infarcts and petechial hemorrhages was confirmed by antemortem biopsy. This clinical and radiologic picture is being increasingly recognized as characteristic of cerebral amyloid angiopathy.
Aged↗
Nimodipine as an add-on therapy for intractable epilepsy.
OBJECTIVE: To analyze the effect of nimodipine in patients with intractable epilepsy. DESIGN: We conducted a double-blind placebo-controlled crossover study in 95 patients. MATERIAL AND METHODS: The dihydropyridine calcium antagonist nimodipine was used as add-on therapy (60 mg four times a day) in a 1-year placebo-controlled crossover study in 71 patients with localization-related epilepsy and 24 with generalized seizure disorders. Of the 95 patients, 81 were receiving two or more antiepileptic drugs. Patients diaries were used to record the number of seizures and any side effects. RESULTS: Nimodipine seemed to be well tolerated during the study; only two patients were unable to complete the study because of probable adverse effects. The trial demonstrated no significant crossover effect and no significant effect of nimodipine on either the mean or the median number of seizures or seizure days. The peak median serum nimodipine level was less than 5 ng/mL in the 78 patients who completed the study. CONCLUSION: This clinical trial found no beneficial effect with use of nimodipine as add-on therapy for intractable epilepsy. Potential reasons for the absence of efficacy of nimodipine may be the inclusion of patients with very refractory seizure disorders or the relatively low serum nimodipine concentrations related to the pharmacokinetic effect of concurrent antiepileptic medication.
Adult↗
Clear cell meningioma. A clinicopathologic study of a potentially aggressive variant of meningioma.
Since clear cell meningioma has only recently been recognized as a morphologic entity, its pathobiology has not been studied. Fourteen examples occurring in seven females and six males, ages 9 to 82 years (mean 29 years), were examined; one was associated with type 2 neurofibromatosis. Of these cases, seven (50%) were spinal-intradural (six lumbar, one thoracic), three (21%) arose in the posterior fossa (cerebellopontine angle), three (21%) were supratentorial, and one (7%) was centered upon the foramen magnum. In one case (8%), two tumors were considered to be independent primaries. One tumor (8%) appeared to show no dural attachment. Thirteen tumors were subject to complete study. All were composed of sheets of clear, glycogen-rich, polygonal cells forming only a few vague whorls. Hyalinization, both stromal and perivascular, was often extensive. Mitoses were rare in primary tumors. Immunohistochemistry showed vimentin and epithelial membrane antigen staining to be reactive in 100%. Stains for S-100 protein and CAM 5.2 were negative. Progesterone and estrogen receptor staining was observed in 77% and 0%, respectively. Ultrastructural study showed abundant cytoplasmic glycogen, a few cytoplasmic lumina, intermediate filaments, interdigitation of cell membranes, and desmosomal junctions. The means, medians, and ranges of proliferating cell nuclear antigen (PCNA) and MIB-1 antigen labeling indices for nonrecurring and recurring tumors were 10.4%, 8.8%, 0.8-23.4% and 11%, 1.4%, 0.1-50.3%, as compared with 7.4%, 6.7%, 2.9-17.2% and 13.3%, 13.4%, 3.3-25.7%, respectively. Twelve successful DNA ploidy studies showed that 11 tumors (85%) were diploid and one was tetraploid; percentage S-phase determinations varied from 4 to 9% (mean 6.0%). Recurrence was noted in eight patients (61%) (five of whom had multiple recurrences); there was local discontinuous spread in two cases (15%) and widespread cranial to spinal metastasis in one case (8%). Three patients (23%) are dead of disease. In summary, clear cell meningiomas are morphologically unique, show no sex predilection, affect primarily the lumbar region and cerebellopontine angle, and despite their benign appearance, may be inordinately aggressive, particularly intracranial examples. No close association was noted between recurrence or clinical outcome and such factors as mitotic activity, PCNA proliferation indices, percent S-phase determination, or DNA ploidy status. In contrast, MIB-1 proliferation indices were appreciably higher among recurring tumors.
Adolescent↗
Basic fibroblast growth factor increases cortical blood flow in vivo.
Basic FGF has recently been shown to produce systemic and cerebral vasodilation. To test the hypothesis that bFGF increases regional cortical blood flow (rCBF), rCBF and brain pHi were measured while bFGF or vehicle was superperfused onto the cortex of rabbits. The results of this study demonstrate that topical application of bFGF causes an increase in rCBF.
Animals↗
Familial paragangliomas of the head and neck.
OBJECTIVE: It has been known for some time that paragangliomas of the head and neck may be familial. Recent evidence suggests genomic imprinting is an important factor in the clinical development of these tumors. In genomic imprinting the imprintable gene is transmitted in a mendelian manner, but expression of the gene is determined by the sex of the transmitting parent. In the case of paragangliomas, the gene does not result in the development of tumors when maternally inherited. The purpose of this study was to determine if this hypothesis correctly predicted the inheritance pattern of familial paraganglioma in a large series of patients. SETTING: A retrospective review of case records of the Mayo Clinic, Rochester, Minn, a tertiary referral center, was performed for the years 1950 to 1992 to identify patients with familial paragangliomas of the head and neck. PATIENTS: A total of 38 patients with familial paragangliomas of the head and neck were identified in nine kindreds. RESULTS: Carotid body tumors were the most common paragangliomas of the head and neck (34 cases). Glomus jugulare or glomus vagale occurred in eight cases. In 16 (42%) of the patients there were multiple tumors. Surgical complications, primarily cranial nerve palsies, were more frequent for tumors larger than 5 cm in diameter. CONCLUSIONS: An autosomal dominant inheritance pattern could be shown for paragangliomas of the head and neck that was consistent with genomic imprinting. It is recommended that all individuals in kindreds with paragangliomas be screened after the age of 16 years to detect early asymptomatic tumors.
Adolescent↗
Endovascular treatment of intracranial aneurysms.
OBJECTIVE: To examine the techniques, reported experiences, and advantages and disadvantages associated with the endovascular treatment of intracranial aneurysms. DESIGN: We review the endovascular techniques used for the treatment of intracranial aneurysms and the sequelae of subarachnoid hemorrhage, which have evolved during the past 10 years. MATERIAL AND METHODS: Two broad categories of endovascular therapy for intracranial aneurysms are described: occlusion of the parent artery and preservation of the parent artery by selective occlusion of the aneurysm with balloons or metallic coils. The Mayo protocol for testing tolerance of patients before permanent balloon occlusion of the parent artery is described, as are the types of aneurysms most amenable to this treatment. In addition, use of balloon angioplasty for cerebral vasospasm after subarachnoid hemorrhage is reviewed. RESULTS: Recent improvements in microcatheter technology have facilitated the safe navigation of percutaneously introduced catheters in the intracranial circulation and selective catheterization of intracranial aneurysms. Surgically difficult aneurysms are now being treated with endovascular techniques more frequently than in the past. Early results from animal experiments and human trials have shown that selective occlusion of aneurysms with metallic coils may have a role in the treatment of intracranial aneurysms. Balloon angioplasty of symptomatic cerebral vasospasm has demonstrated improvement in neurologic function in approximately 70% of patients. CONCLUSION: As technology continues to improve and as greater experience is obtained, interventional neuroradiologists will continue to have an increasingly important role in the treatment of intracranial aneurysms.
Angiography, Digital Subtraction↗
Vascular malformations and intractable epilepsy: outcome after surgical treatment.
OBJECTIVE: To review our recent experience with surgical treatment of patients with vascular malformations and intractable partial epilepsy. DESIGN: We retrospectively studied 20 consecutive Mayo patients who had undergone surgical treatment of medically refractory partial epilepsy and had cerebral vascular malformations. MATERIAL AND METHODS: Seizures were the initial symptom in all 13 female and 7 male patients, none of whom had a history of a symptomatic intracerebral hemorrhage. Magnetic resonance imaging (MRI) or pathologic examination, or both, indicated the presence of remote hemorrhage associated with the vascular lesion in 18 patients. MRI disclosed 36 vascular malformations (32 cavernous and 4 arteriovenous malformations) in the 20 patients. MRI was more sensitive and specific than computed tomography for their detection and characterization. The operative strategy in all patients included complete resection of the vascular malformation. A modified Engel classification (based on four classes) was used to determine the outcome of seizures. RESULTS: Postoperatively, 15 patients were free of seizures, and 3 patients had at least a 90% decrease in number of seizures. Only two patients had an unfavorable outcome. Neither the age at onset of seizures nor the duration of seizures seemed to affect the outcome. The site of the vascular malformation was less important than precise correlation between the site of onset of seizure activity and the corresponding vascular malformation. The presence of coexistent ipsilateral atrophy of the hippocampal formation should be sought, and the operative strategy should be appropriately modified. CONCLUSION: In the absence of dual pathologic conditions, lesionectomy can yield a seizure-free outcome in patients with intractable partial epilepsy and cerebral vascular malformations.
Adult↗
Moyamoya disease: the disorder and surgical treatment.
OBJECTIVE: To discuss the clinical features of moyamoya disease, the studies that aid in diagnosing this disorder, and the reported outcomes of surgical treatment. DESIGN: We review the manifestations of moyamoya disease in children and adults and the recent reports of the various surgical procedures. MATERIAL AND METHODS: Moyamoya disease is a chronic cerebrovascular disorder in which stenosis of the major arteries of the circle of Willis at the base of the skull progresses to occlusion. The diagnosis is based on the angiographic findings of the "puff of smoke" appearance of the abnormal capillary vessels at the base of the skull. Three surgical procedures are used to manage this disease: anastomosis of the superficial temporal artery to the middle cerebral artery, encephalomyosynangiosis, and encephaloduro-arteriosynangiosis. RESULTS: In children with this disease, cerebral ischemic events, including strokes, occur. In adults, the fragile abnormal vessels can rupture and cause intracerebral hemorrhage. The mortality rate for adults is higher than that for children. Most published reports support the efficacy of surgical treatment in children but not in adults. CONCLUSIONS: The natural history of moyamoya disease is poor; neurologic deterioration due to strokes and hemorrhage is progressive. Seizures and intellectual deterioration can occur.
Adolescent↗
Carotid artery occlusion: positive predictive value of duplex sonography compared with arteriography.
PURPOSE: Duplex ultrasonography is an accurate, noninvasive method for diagnosing, characterizing, and classifying atherosclerotic stenoses of the extracranial carotid artery system. To date, however, no large series has studied the predictive value of duplex sonography in the diagnosis of carotid artery occlusion, an important consideration, given the marked difference in clinical treatment between patients with high-grade stenosis (surgical therapy) and those with occlusive disease (nonsurgical therapy). METHODS: We retrospectively reviewed 158 patients with 174 occluded carotid artery segments (examined over a 6 1/2-year period) to determine the predicative value of duplex sonography in differentiating carotid artery occlusion from high-grade stenosis. RESULTS: All patients had arteriographic correlation. Duplex ultrasonography had a positive predictive value of 92.5% (7.5% false-positive rate; 95% confidence interval, 3.6% to 11.4%) in establishing a diagnosis of carotid artery occlusion. Further analysis revealed no significant improvement in the false-positive rate with the addition of color Doppler flow imaging to high-resolution B-mode scanning and pulsed Doppler spectral analysis. Predictive value increased to 96.7% (95% confidence interval, 90.7% to 99.3%) over the last 2 years of the study, a statistically significant improvement. CONCLUSIONS: We believe that duplex ultrasonography is an acceptably accurate method for diagnosing carotid arterial occlusion in most patients. Arteriography should be reserved for patients with symptoms who are surgical candidates to identify those who may still have a surgically correctable high-grade stenosis.
Aged↗
The significance of atypia and histologic malignancy in pilocytic astrocytoma of the cerebellum: a clinicopathologic and flow cytometric study.
Biologically malignant pilocytic astrocytomas are rare. Precise morphologic criteria permitting their identification and clinically meaningful distinction from more ordinary pilocytic astrocytomas have not been developed. The histologic grading schemes applied to fibrillary astrocytomas--ones based on nuclear atypia, increased cellularity, mitotic activity, endothelial proliferation, and necrosis--are thought not to correlate with prognosis in pilocytic astrocytomas. Nonetheless, these features were systematically sought in 107 cerebellar pilocytic astrocytomas, four of which were histologically malignant. The clinical, morphologic, and flow cytometric features of these cases were studied. The incidence of histologic malignancy occurring spontaneously in otherwise typical pilocytic astrocytomas was 0.9%; that occurring after radiation was 1.8%. The four histologically malignant tumors occurred in two males and two females, ages 6 to 18 years. All showed increased mitotic activity (three to five mitoses per high-power microscopic field [250x]). Endothelial proliferation and necrosis were present in three and two cases each. DNA ploidy analysis showed the spontaneously occurring malignant-appearing tumors to be aneuploid, whereas both previously radiated tumors were tetraploid; 5% to 11% of cells were in S phase. The appearance of histologic malignancy in pilocytic astrocytoma is rare and less reliably correlated with prognosis than in patients with fibrillary astrocytomas. Essential features of such tumors include a high mitotic index and perhaps a high percentage of cells in S phase.
Adolescent↗
Surgical treatment of recurrent carotid artery stenosis.
Ninety-two surgical procedures were performed in 82 patients for recurrent carotid artery stenosis. The etiology was recurrent atherosclerosis in 45 cases, myointimal hyperplasia in 20, organized thrombus without a significant underlying plaque in 20, and scarring along the proximal arteriotomy site in seven. The operations included a repeat endarterectomy in 66 cases and reconstruction with an interposition graft in 22. All five major neurological complications occurred in symptomatic patients, and included three instances of intraoperative embolization during exposure of the carotid artery. The majority of neurological complications occurred in symptomatic patients who had intraluminal thrombus confirmed at surgery. There were four perioperative deaths, due to cerebral hemorrhage in two patients and myocardial infarction in two. In the patients whose original surgery was performed at the Mayo Clinic, the risk of recurrent carotid artery stenosis was 3.1% with a primary closure compared to 1.6% when a patch graft was used. These results indicate that surgery for recurrent carotid artery stenosis is technically more difficult and carries a significantly higher risk than surgery for primary disease. The difficulty is due to the friable recurrent plaque associated with intraluminal thrombus, which increases the risk of embolization during carotid artery exposure. In the majority of patients with recurrent atherosclerosis, a repeat endarterectomy can be achieved. However, in some patients, there is scarring without a definite plane of cleavage between the recurrent disease and the underlying media, making an endarterectomy difficult. In these cases, excision of the diseased segment and reconstruction with an interposition graft is the best treatment. The findings presented here also suggest that closure of the original arteriotomy with a patch graft decreases the risk of recurrent carotid artery stenosis.
Carotid Stenosis↗