Cumulative radiation dose during hospitalization for aneurysmal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Radiation exposure from neurointerventional procedures and diagnostic neuroimaging can be substantial, with many recommendations offered to guide the interventionalist in the conscientious use of ionizing radiation. Patients presenting with an aneurysmal subarachnoid hemorrhage can undergo multiple imaging procedures during a prolonged hospital course. Therefore, we reviewed a cohort of such patients to identify the sources and quantify the cumulative radiation exposure seen during their hospitalization. MATERIALS AND METHODS: We retrospectively reviewed a single-center experience with these patients to define the potential for short-term skin injury and long-term oncologic risk due to absorbed radiation dose and sources of ionizing radiation and their contribution to the cumulative absorbed dose to the cranial tissues. RESULTS: We demonstrated that substantial cumulative doses can be seen, with 87% of the cumulative absorbed dose occurring during neurointerventional procedures and 7% from CT. Mathematic modeling was performed identifying potential techniques to further reduce the cumulative radiation absorbed dose to these patients. CONCLUSIONS: We conclude that repetitive irradiation during the care of patients with aneurysmal subarachnoid hemorrhage can result in significant cumulative doses and a variety of techniques can be applied to reduce this absorbed dose. Use of radiation for diagnostic and therapeutic purposes during prolonged procedures of patients with subarachnoid hemorrhage demands diligence throughout the hospitalization.

Performance and training standards for endovascular ischemic stroke treatment.

Stroke is the third leading cause of death in the USA, Canada, Europe, and Japan. According to the American Heart Association and the American Stroke Association, there are now 750,000 new strokes that occur each year, resulting in 200,000 deaths, or 1 of every 16 deaths, per year in the USA alone. Endovascular therapy for patients with acute ischemic stroke is an area of intense investigation. The American Stroke Association has given a qualified endorsement of intra-arterial thrombolysis in selected patients. Intra-arterial thrombolysis has been studied in two randomized trials and numerous case series. Although two devices have been granted FDA approval with an indication for mechanical stroke thrombectomy, none of these thrombectomy devices has demonstrated efficacy for the improvement of patient outcomes. The purpose of the present document is to define what constitutes adequate training to perform neuroendovascular procedures in patients with acute ischemic stroke and what performance standards should be adopted to assess outcomes. These guidelines have been written and approved by multiple neuroscience societies which historically have been directly involved in the medical, surgical and endovascular care of patients with acute stroke. The participating member organizations of the Neurovascular Coalition involved in the writing and endorsement of this document are the Society of NeuroInterventional Surgery, the American Academy of Neurology, the American Association of Neurological Surgeons/Congress of Neurological Surgeons Cerebrovascular Section, and the Society of Vascular & Interventional Neurology.

Neuroform stent assisted aneurysm treatment: evolving treatment strategies, complications and results of long term follow-up.

INTRODUCTION: This report details experience with the Neuroform stent, with an emphasis on evolving treatment strategies, complication rates and treatment durability. METHODS: All patients undergoing Neuroform stent assisted aneurysm treatment were registered in prospectively maintained endovascular databases at two institutions. RESULTS: 284 patients with 302 aneurysms underwent aneurysm treatment with Neuroform during a 42-month study period. Imaging follow-up was available for 166 of 286 saccular aneurysms which were treated with stents and coils (average interval 12.9 months). 80 demonstrated progressive thrombosis (48.2%), 40 were unchanged (24.1%) and 46 (27.7%) demonstrated re-canalization, 25 (15.1%) of which were major recanalizations requiring retreatment. The vast majority of recanalizations and retreatments were observed in large or giant aneurysms. A cumulative total of 25 ischemic strokes (8.8%) and eight neurovascular deaths (2.8%) were recorded in these patients. Ten of these strokes were associated with transient deficits which went on to complete resolution by the time of discharge or at the initial clinical follow-up, yielding a significant stroke rate of 5.3%. Delayed (>48 h) complications, including four deaths-related to stroke (n=2, 6 days and 8 weeks post-procedure) and spontaneous parenchymal hemorrhages (n=2)-represent events which are a direct consequence of stenting and likely would not have been encountered in the context of standard non-stent supported embolization techniques. CONCLUSION: Neuroform facilitates the endovascular treatment of complex and wide necked cerebral aneurysms. However, complete occlusion at angiographic follow-up remains uncommon and is observed in only one-third of patients. Delayed complications (>48 h) represent an important component of the overall complications associated with Neuroform assisted aneurysm embolization.

CSF neutrophils are implicated in the development of vasospasm in subarachnoid hemorrhage.

BACKGROUND: Cerebral vasospasm is a significant cause of morbidity in patients after aneurysmal subarachnoid hemorrhage (aSAH). There are few effective treatments. The search for new treatments has focused predominantly on dilating cerebral blood vessels. Growing evidence supports a role for inflammation in its pathogenesis but no potential target for intervention has emerged. METHODS: CSF and clinical information from patients with aSAH were collected. Additionally, tyrosine modifications by stable isotope dilution HPLC with online tandem mass spectrometry were quantified in CSF samples. RESULTS: We report an association between neutrophil accumulation in the cerebrospinal fluid of patients with aSAH and the development of vasospasm. In particular, CSF neutrophil content of >62% on the third day after aSAH is an independent predictor of the later development of vasospasm (OR 6.8, 95% CI 2.0-23.3, P = 0.002). Further, activity of myeloperoxidase and NADPH oxidase is elevated in aSAH suggesting a role for modification of CSF proteins by reactive oxidant species. CONCLUSIONS: Neutrophil percentage is an independent predictor of vasospasm in aSAH patients, days prior to its onset suggesting a role of neutrophils in vasospasm. The activity of neutrophil enzymes is also increased suggesting a mechanism for blood vessel damage. Inflammation mediated by neutrophils is a potential target for therapies in vasospasm. More study is necessary to determine the mechanism by which neutrophils damage cerebral blood vessels.

Performance and training standards for endovascular ischemic stroke treatment.

Stroke is the third leading cause of death in the USA, Canada, Europe, and Japan. According to the American Heart Association and the American Stroke Association, there are now 750,000 new strokes that occur each year, resulting in 200,000 deaths, or 1 of every 16 deaths, per year in the USA alone. Endovascular therapy for patients with acute ischemic stroke is an area of intense investigation. The American Stroke Association has given a qualified endorsement of intra-arterial thrombolysis in selected patients. Intra-arterial thrombolysis has been studied in two randomized trials and numerous case series. Although two devices have been granted FDA approval with an indication for mechanical stroke thrombectomy, none of these thrombectomy devices has demonstrated efficacy for the improvement of patient outcomes. The purpose of the present document is to define what constitutes adequate training to perform neuroendovascular procedures in patients with acute ischemic stroke and what performance standards should be adopted to assess outcomes. These guidelines have been written and approved by multiple neuroscience societies which historically have been directly involved in the medical, surgical and endovascular care of patients with acute stroke. The participating member organizations of the Neurovascular Coalition involved in the writing and endorsement of this document are the Society of NeuroInterventional Surgery, the American Academy of Neurology, the American Association of Neurological Surgeons/Congress of Neurological Surgeons Cerebrovascular Section, and the Society of Vascular & Interventional Neurology.

Influence of patient age and stenosis location on wingspan in-stent restenosis.

BACKGROUND AND PURPOSE: Wingspan is a self-expanding, microcatheter-delivered microstent specifically designed for the treatment of symptomatic intracranial atherosclerotic disease. Our aim was to discuss the effect of patient age and lesion location on in-stent restenosis (ISR) rates after percutaneous transluminal angioplasty and stenting (PTAS) with the Wingspan system. MATERIALS AND METHODS: Clinical and angiographic follow-up results were recorded for all patients from 5 participating institutions. ISR was defined as >50% stenosis within or immediately adjacent (within 5 mm) to the implanted stent and >20% absolute luminal loss. For the present analysis, patients were stratified into younger (55 years) age groups. RESULTS: ISR occurred at a rate of 45.2% (14/31) in the younger group and 24.2% (15/62) in the older group (odds ratio, 2.6; 95% confidence interval, 1.03-6.5). In the younger group, ISR occurred after treatment of 13/26 (50%) anterior circulation lesions versus only 1/5 (20%) posterior circulation lesions. In the older group, ISR occurred in 9/29 (31.0%) anterior circulation lesions and 6/33 (18.2%) posterior circulation lesions. In young patients, internal carotid artery lesions (10/17 treated, 58.8%), especially those involving the supraclinoid segment (8/9, 88.9%), were very prone to ISR. When patients of all ages were considered, supraclinoid segment lesions had much higher rates of both ISR (66.6% versus 24.4%) and symptomatic ISR (40% versus 3.9%) in comparison with all other locations. CONCLUSION: Post-Wingspan ISR is more common in younger patients. This increased risk can be accounted for by a high prevalence of anterior circulation lesions in this population, specifically those affecting the supraclinoid segment, which are much more prone to ISR and symptomatic ISR than all other lesions.

Optimised cantilever biosensor with piezoresistive read-out.

We present a cantilever-based biochemical sensor with piezoresistive read-out which has been optimised for measuring surface stress. The resistors and the electrical wiring on the chip are encapsulated in low-pressure chemical vapor deposition (LPCVD) silicon nitride, so that the chip is well suited for operation in liquids. The wiring is titanium silicide which-in contrast to conventional metal wiring-is compatible with the high-temperature LPCVD coating process.

Stent-assisted angioplasty of intracranial vertebrobasilar atherosclerosis: an initial experience.

OBJECT: Patients with intracranial vertebrobasilar artery (VBA) atherosclerotic occlusive disease have few therapeutic options. Unfortunately, VBA transient ischemic attacks (TIAs) herald a lethal or devastating event within 5 years in 25 to 30% of patients. The authors report their initial experience with eight patients in whom medically refractory TIAs secondary to intracranial posterior circulation atherosclerotic occlusive lesions were treated with stent-assisted angioplasty. METHODS: Eight patients (six men), ranging in age from 43 to 77 years, experienced signs and symptoms of VBA insufficiency despite combination therapy with warfarin and antiplatelet agents. Angiographic studies revealed severe distal vertebral (four patients), proximal basilar (one patient), or proximal and midbasilar stenoses (three patients). Aspirin and clopidogrel were administered for 3 days before primary angioplasty and stent placement, and this regimen was maintained by the patients on discharge. Patients underwent heparinization during the procedure and were given a bolus and 12-hour infusion of abciximab. A neurologist specializing in stroke evaluated all patients before and after the procedure. The VBAs in all patients were successfully revascularized with 7 to 28% residual stenosis. Six patients experienced no neurological complications. One patient died the evening of the procedure due to a massive subarachnoid hemorrhage. Two patients had groin hematomas, one developed congestive heart failure, and one had transient encephalopathy. All surviving patients are asymptomatic up to 8 months postoperatively. CONCLUSIONS: Although primary intracranial VBA angioplasty with stent insertion is technically feasible, complications associated with the procedure can be life threatening. As experience is gained with this procedure, it may be offered routinely as an alternative therapy to patients with medically refractory posterior circulation occlusive disease that may develop into catastrophic VBA insufficiency.

Propofol inhibits epileptiform activity in rat hippocampal slices.

Propofol (2,6 di-isopropylphenol) is an intravenous general anesthetic used widely in neuroanesthesia, as a sedative in intensive care units, and has successfully aborted refractory status epilepticus. We investigated the effects of propofol on epileptiform activity in rat hippocampal slices. Interictal epileptiform activity was produced by bath applying one of the following: picrotoxin (PTX; 10 and 50 microM), bicucculine methiodide (BMI; 10 and 50 microM), 4-aminopyridine (4-AP; 50 microM), 8.5 mM [K+]o or 0 [Mg2+]o artificial cerebrospinal fluid. Propofol was then added in increasing concentrations and the effect on the rate of extracellular field epileptiform discharges was measured. Ictal-like discharges (> 2 Hz for > 2 s) were produced by 7.5 mM [K+]o and pilocarpine (10 microM). Propofol (30 micrograms/ml, 168 microM) completely abolished discharges induced by 8.5 mM [K+]o and at 60 micrograms/ml (337 mM) completely suppressed discharges induced by 4-AP and 0 [Mg2+]o. Propofol was less effective in reducing discharges produced by GABAA/Cl- receptor complex antagonists. Propofol at a concentration of 300 micrograms/ml (1.7 mM) was needed to reduce BMI-induced (50 microM) discharges by 77% and only reduced PTX-induced (50 microM) discharges by 20%. Ictal-like discharges produced by pilocarpine were disrupted by low concentrations of propofol (3-10 micrograms/ml, 16.9-56.2 microM) and the duration of the ictal-like discharge period was significantly reduced. We found that propofol has significant in vitro antiepileptic effects. Additionally, propofol was less effective against GABAA antagonists suggesting that the GABAA receptor complex is the site of its action.

Reduced transverse spinal area secondary to burst fractures: is there a relationship to neurologic injury?

A retrospective case-control study was undertaken to determine the best technique to measure neural canal encroachment at each lumbar level following burst fracture and its relationship to the presence of neurologic deficit. Only patients with postinjury CT scans demonstrating a disrupted posterior body with a retropulsed bone fragment were included. Patients were divided into groups based on the level of bony injury (T12-L5) and neurologic status. Neurologic injury was classified as follows: normal (N), root (R), or cauda equina/conus/paraplegic/paraparetic (C/P). The mean transverse spinal area (TSA, cm2), spinal canal percentage patency (PP), and midsagittal diameter (MSD) were determined for each neurologic group and lumbar level. A "calculated" TSA, based on midsagittal and anterior-posterior diameters, was also derived for each patient. The data were compared level by level and correlated with the patient's neurologic status. At L1, the critical TSA was 1.0 cm2. All patients with TSAs less than this were paraplegic. At both T12 and L1, TSAs in the range of 1.0-1.25 cm2 were observed in both normal and neurologically impaired patients. A critically significant TSA was not established for levels T12, L2, L3, L4, or L5; however, the data indicated that a smaller TSA can be tolerated at successively caudal levels without neurologic deficit. No meaningful correlation between root injury and TSA was observed. The data also indicated that measurement of TSA is a more accurate method for evaluating neural canal encroachment than PP or MSD. The "calculated" TSA is a simple, objective method for obtaining this information without the aid of a computer. This study suggests that absolute TSA should be utilized in future studies evaluating decompressive treatment of thoracolumbar pathology.

Determination of 58Co-vitamin B12 absorption in pernicious anemia by use of whole-body counting: Reproducibility and control of gut transit time.

In 15 patients with pernicious anemia, the fractional retention of 58Co-cyanocobalamin (FRB12) without administration of intrinsic factor (IF) averaged 4.9% (range 0-12.7). With administration of IF, FRB12 averaged 32.7% (range 26.6--42.3) in the patients and 65.6% (range 38.8--84.6) in 16 control subjects. The gut transit time for vitamin B12 was evaluated from the excretion of radiopaque pellets given concomitantly with the 58Co-vitamin B12. The retention of the pellets was positively correlated to that of the non-absorbed 58Co-B12. Control of the gut transit time is recommended at each examination of FRB12 in order to avoid falsely high values due to the retention of non-absorbed 58Co-B12. We found a good reproducibility of FRB12 when determined in fasting subjects, and it is therefore unnecessary to give the patients a B12-free meal prior to the examination. As the FRB12 in all probability is only a little lower than the fractional absorption, the present method is applicalble for the determination of B12 absorption.

Improvement of recalcitrant psoriasis vulgaris after tonsillectomy.

To study the effect of tonsillectomy as a possible part of the treatment of infection-released, relapsing and recalcitrant (to topical therapy and courses of penicillin) psoriasis vulgaris in children and adolescents and to test a possible correlation between tonsillitis and exacerbations of psoriasis vulgaris, a retrospective study (charts and questionnaires) of the course of psoriasis after tonsillectomy was undertaken in 74 patients with such psoriasis. Each patient served as his own control. At tonsillectomy the average age of patients and the duration of psoriasis were 14-2 years and 4-5 years, respectively, while the average follow-up period was 4-5 years. The clearing of psoriasis vulgaris was stastically significant, p less than 0-01, as 1/3 of the patients obtained clearing of psoriasis throughout the entire follow-up period, while an additional 1/3 noticed considerable improvement of their psoriasis. After having tried both topical therapy of various sorts and courses of penicillin, tonsillectomy might be taken into consideration in relapsing, recalcitrant psoriasis vulgaris in children and adolescents.

Improvement of refractory psoriasis vulgaris after tonsillectomy.

In order to ascertain what effect tonsillectomy may have in the treatment of children and adolescents with recurring psoriasis vulgaris, refractory to topical therapy and courses of penicillin, and triggered by infection, and also to test a possible correlation between tonsillitis and exacerbations of psoriasis, a retrospective study of the course of psoriasis after tonsillectomy, using charts and questionnaires, was undertaken in 74 psoriatic patients. Each patient served as his won control. The average age of the patients at tonsillectomy and the duration of psoriasis were 14.2 years and 4.5 years, respectively, while the average follow-up period was 4.5 years. The clearing of the psoriasis was statistically significant (p less than 0.01) as it occurred throughout the entire follow-up period in one-third of the patients, while an additional third noticed considerable improvement of their psoriasis. After trying tropical therapies of various sorts as well as courses of penicillin, tonsillectomy might be considered for recurring, refractory psoriasis vulgaris in children and adolescents.