RESUMO
BACKGROUND AND PURPOSE: PTA effectively treats vasospasm and arterial disease in peripheral, coronary, and large proximal cerebral vessels but rarely reaches small vessels like the distal MCA beyond the bifurcation. Our purpose was to evaluate the safety and efficacy of PTA for distal MCA occlusions in acute ischemic stroke. MATERIALS AND METHODS: Seven patients had strokes in branches of their MCAs. Following diagnostic angiography, all received microballoon angioplasty and various combinations of IA alteplase (rtPA), abciximab, and/or nitroglycerin. Two also underwent stent placement. Comprehensive retrospective review of the patients' records was performed. Patients' NIHSS scores were reassessed before discharge. Recanalization was evaluated by angiography after treatment and at follow-up. RESULTS: PTA was successfully performed in 7 patients without treatment-associated intracerebral hemorrhage. Two patients received distal MCA angioplasty as a secondary intervention: 1 following failed treatment with a Merci retriever and the other after successful removal of proximal clot with a Merci retriever. One patient did not recover from the initial ischemic event despite an excellent angiographic result. Complete recanalization (modified TIMI grade 4) was achieved in 4 patients and near-complete recanalization with mild flow deficit (modified TIMI grade 3), in 3 patients. CONCLUSIONS: PTA of the distal MCA with a microballoon is safe and effective for acute ischemic stroke. This case series demonstrates that endovascular treatment beyond the MCA bifurcation can dramatically reverse neurologic deficits.
Assuntos
Angioplastia com Balão/métodos , Isquemia Encefálica/terapia , Revascularização Cerebral/métodos , Infarto da Artéria Cerebral Média/terapia , Doença Aguda , Adulto , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/diagnóstico por imagem , Angiografia Cerebral , Feminino , Seguimentos , Humanos , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , StentsRESUMO
We compared the rates of recanalization cerebral infarct and hemorrhage between intra-arterial (i.a.) reteplase and intravenous (i.v.) alteplase thrombolysis in a canine model of basilar artery thrombosis. Thrombosis was induced by injecting a clot in the basilar artery of 13 anesthetized dogs via superselective catheterization. The animals were randomized in a blinded fashion, 2 h after clot injection and verification of arterial occlusion, to receive i.v. alteplase 0.9 mg/kg over 60 min and i.a. placebo, or i.a. reteplase 0.09 units/kg over 20 min, equivalent to one-half the alteplase dose, and i.v. placebo. Recanalization was studied for 6 h after treatment with serial angiography; the images were later graded in a blinded fashion. Blinded interpretation of postmortem MRI was performed to assess the presence of brain infarcts and/or hemorrhage. At 3 h after initiation of treatment, partial or complete recanalization was observed in one of six dogs in the i.v. alteplase group and in five of seven in the i.a. reteplase group (P = 0.08). At 6 h, no significant difference in partial or complete recanalization was observed between the groups (two of six vs. five of seven; P = 0.20). Postmortem MRI revealed infarcts in four of six animals treated with i.v. alteplase and three of seven treated with i.a. reteplase (P = 0.4). Intracerebral hemorrhage was more common in the i.v. alteplase group (four of six vs. none of seven; P = 0.02). This study thus suggests that i.a. thrombolysis affords a recanalization rate similar to that of i.v. thrombolysis, but with a lower rate of intracerebral hemorrhage.
Assuntos
Artéria Basilar , Fibrinolíticos/administração & dosagem , Trombose Intracraniana/tratamento farmacológico , Terapia Trombolítica/métodos , Ativador de Plasminogênio Tecidual/administração & dosagem , Animais , Hemorragia Cerebral/etiologia , Hemorragia Cerebral/prevenção & controle , Infarto Cerebral/etiologia , Infarto Cerebral/prevenção & controle , Modelos Animais de Doenças , Cães , Feminino , Infusões Intra-Arteriais , Infusões Intravenosas , Trombose Intracraniana/complicações , Masculino , Distribuição Aleatória , Proteínas Recombinantes/administração & dosagem , Resultado do TratamentoRESUMO
Five cases of degenerative subaxial spondylolisthesis of osteoarthritic etiology associated with significant cervical spondylotic myelopathy are described with treatment recommendations. Diagnostic studies included cervical plain films with flexion/extension, magnetic resonance imaging, and computed tomography/myelography. All patients had at least 2 mm of spondylolisthesis at one or more levels, and two patients had movement evident on flexion/extension films. Posterior laminectomy with AME (American Medical Electronics, Richardson, TX, U.S.A.) lateral mass plate and bone fusion was successfully performed in all five patients, three of whom improved one grade on the Nurick classification, whereas the rest improved within the same grade.
Assuntos
Vértebras Cervicais/cirurgia , Espondilolistese/diagnóstico , Espondilolistese/cirurgia , Idoso , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/patologia , Feminino , Seguimentos , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Osteoartrite/complicações , Fusão Vertebral , Osteofitose Vertebral/complicações , Osteofitose Vertebral/diagnóstico , Osteofitose Vertebral/cirurgia , Espondilolistese/complicações , Espondilolistese/etiologia , Tomografia Computadorizada por Raios XRESUMO
It has been postulated that phosphorylation of the carboxy terminus sidearms of neurofilaments (NFs) increases axon diameter through repulsive electrostatic forces that increase sidearm extension and interfilament spacing. To evaluate this hypothesis, the relationships among NF phosphorylation, NF spacing, and axon diameter were examined in uninjured and spinal cord-transected larval sea lampreys (Petromyzon marinus). In untransected animals, axon diameters in the spinal cord varied from 0.5 to 50 microns. Antibodies specific for highly phosphorylated NFs labeled only large axons (> 10 microns), whereas antibodies for lightly phosphorylated NFs labeled medium-sized and small axons more darkly than large axons. For most axons in untransected animals, diameter was inversely related to NF packing density, but the interfilament distances of the largest axons were only 1.5 times those of the smallest axons. In addition, the lightly phosphorylated NFs of the small axons in the dorsal columns were widely spaced, suggesting that phosphorylation of NFs does not rigidly determine their spacing and that NF spacing does not rigidly determine axon diameter. Regenerating neurites of giant reticulospinal axons (GRAs) have diameters only 5-10% of those of their parent axons. If axon caliber is controlled by NF phosphorylation via mutual electrostatic repulsion, then NFs in the slender regenerating neurites should be lightly phosphorylated and densely packed (similar to NFs in uninjured small caliber axons), whereas NFs in the parent GRAs should be highly phosphorylated and loosely packed. However, although linear density of NFs (the number of NFs per micrometer) in these slender regenerating neurites was twice that in their parent axons, they were highly phosphorylated. Following sectioning of these same axons close to the cell body, axon-like neurites regenerated ectopically from dendritic tips. These ectopically regenerating neurites had NF linear densities 2.5 times those of uncut GRAs but were also highly phosphorylated. Thus, in the lamprey, NF phosphorylation may not control axon diameter directly through electrorepulsive charges that increase NF sidearm extension and NF spacing. It is possible that phosphorylation of NFs normally influences axon diameter through indirect mechanisms, such as the slowing of NF transport and the formation of a stationary cytoskeletal lattice, as has been proposed by others. Such a mechanism could be overridden during regeneration, when a more compact, phosphorylated NF backbone might add mechanical stiffness that promotes the advance of the neurite tip within a restricted central nervous system environment.