Time Is Brain—Quantified

Flat detector CT in the evaluation of brain parenchyma, intracranial vasculature, and cerebral blood volume: a pilot study in patients with acute symptoms of cerebral ischemia

BACKGROUND AND PURPOSE

The viability of both brain parenchyma and vascular anatomy is important in estimating the risk and potential benefit of revascularization in patients with acute cerebral ischemia. We tested the hypothesis that when used in conjunction with IV contrast, FD-CT imaging would provide both anatomic and physiologic information that would correlate well with that obtained by using standard multisection CT techniques.

MATERIALS AND METHODS

Imaging of brain parenchyma (FD-CT), cerebral vasculature (FD-CTA), and cerebral blood volume (FD-CBV) was performed in 10 patients. All patients also underwent conventional multisection CT, CTA, CTP (including CBV, CTP-CBV), and conventional catheter angiography. Correlation of the corresponding images was performed by 2 experienced neuroradiologists.

RESULTS

There was good correlation of the CBV color maps and absolute values between FD-CBV and CTP-CBV (correlation coefficient, 0.72; P < .001). The Bland-Altman test showed a mean difference of CBV values between FD-CT and CTP-CBV of 0.04 ± 0.55 mL/100 mL. All vascular lesions identified with standard CTA were also visualized with FD-CTA. Visualization of brain parenchyma by using FD-CT was poor compared with that obtained by using standard CT.

CONCLUSIONS

Both imaging of the cerebral vasculature and measurements of CBV by using FD-CT are feasible. The resulting vascular images and CBV measurements compared well with ones made by using standard CT techniques. The ability to measure CBV and also visualize cerebral vasculature in the angiography suite may offer significant advantages in the management of patients. FD-CT is not yet equivalent to CT for imaging of brain parenchyma.

TAT-NEP1-40 as a novel therapeutic candidate for axonal regeneration and functional recovery after stroke

Currently available therapeutics has been less effective in promoting functional recovery from stroke or other injuries in the central nervous system (CNS). Axonal damage is a characteristic pathology seen in CNS injuries. Previously, it was reported that Nogo-A extracellular peptide residues 1-40 (NEP1-40), a competitive antagonist of Nogo-66 receptor (NgR1), has the ability to promote axonal regrowth and functional recovery after CNS injury. However, delivery of the therapeutic proteins into the brain parenchyma is limited due to its inability to cross the blood-brain barrier (BBB). We first generated a biologically active NEP1-40 fusion protein containing the protein transduction domain (PTD) of the transactivator of transcription (TAT), TAT-NEP1-40, which crosses the BBB in vivo after systemic delivery. The TAT-NEP1-40 can protect PC12 cells against oxygen and glucose deprivation (OGD) and promote neurite outgrowth when added exogenously to culture medium. The TAT-NEP1-40 protein transduced into the brain continued to sustain biological activities and protected the brain against ischemia/reperfusion injury through inhibition of neuronal apoptosis. Collectively, our data suggest that TAT-NEP1-40 may be a novel therapeutic candidate for axonal regeneration and functional recovery from CNS injuries such as cerebral hypoxia-ischemia, cerebral hemorrhage, brain trauma, and also for spinal cord injury.

Safety of tPA in stroke mimics and neuroimaging-negative cerebral ischemia

BACKGROUND

Patients with acute neurologic symptoms may have other causes simulating ischemic stroke, called stroke mimics (SM), but they may also have averted strokes that do not appear as infarcts on neuroimaging, which we call neuroimaging-negative cerebral ischemia (NNCI). We determined the safety and outcome of IV thrombolysis within 3 hours of symptom onset in patients with SM and NNCI.

METHODS

Patients treated with IV tissue plasminogen activator (tPA) within 3 hours of symptom onset were identified from our stroke registry from June 2004 to October 2008. We collected admission NIH Stroke Scale (NIHSS) score, modified Rankin score (mRS), length of stay (LOS), symptomatic intracerebral hemorrhage (sICH), and discharge diagnosis.

RESULTS

Among 512 treated patients, 21% were found not to have an infarct on follow-up imaging. In the SM group (14%), average age was 55 years, median admission NIHSS was 7, median discharge NIHSS was 0, median LOS was 3 days, and there were no instances of sICH. The most common etiologies were seizure, complicated migraine, and conversion disorder. In the NNCI group (7%), average age was 61 years, median admission NIHSS was 7, median discharge NIHSS was 0, median LOS was 3 days, and there were no instances of sICH. Nearly all SM (87%) and NNCI (91%) patients were functionally independent on discharge (mRS 0-1).

CONCLUSIONS

Our data support the safety of administering IV tissue plasminogen activator to patients with suspected acute cerebral ischemia within 3 hours of symptom onset, even when the diagnosis ultimately is found not to be stroke or imaging does not show an infarct.

Stability of large diffusion/perfusion mismatch in anterior circulation strokes for 4 or more hours

Background

The stability of hypoperfused brain tissue in stroke patients with major artery occlusions is unknown. The purpose of this study was to determine the persistence of a diffusion/perfusion mismatch in patients with ICA or proximal MCA occlusions.

Methods

Fourteen patients with ICA and/or proximal MCA occlusion and a diffusion/perfusion mismatch at presentation were studied. All were enrolled in a pilot randomized study of normobaric oxygen therapy. None received thrombolytic therapy; 8 received normobaric oxygen and 6 room air. Diffusion/perfusion MRI was performed at baseline, 4 hours, 24 hours, and 1 week. Abnormal DWI, ADC, and MTT volumes were determined using standard image analysis methods.

Results

The mean time from symptom onset to baseline MRI was 7.5 ± 1 hours. Across all 4 time points there was a significant difference in DWI lesion (ANOVA, P < 0.0001) and abnormal MTT volumes (ANOVA, P < 0.01) with the 24 hour and 1 week abnormal volumes different from the earlier studies. However, comparing baseline and 4 hour scans, there was no significant interval change in the mean abnormal DWI volume (29.4 ± 8.2 ml vs. 28.1 ± 7.4 ml) or abnormal MTT volumes (137 ± 17.7 ml vs. 130.9 ± 13.8). By 24 hours, only 2 patients did not maintain a mismatch of 20% or greater.

Conclusions

Patients who present outside the time window for thrombolytic therapy, and who have a large diffusion/perfusion mismatch on MRI may have a stable mismatch for 4 or more hours.

Introduction: Stockholm stroke symposium - from genes to acute care

The acute stroke research field is dynamic and exciting with several clinical breakthroughs, which give reason for optimism. There is gradually a broader understanding of the genetic linkage with different aspects of stroke. As a majority of stroke cases are caused by thrombo-embolism with blocking of one or more of the cerebral arteries, the obvious acute treatment strategy is to remove the occluded vessel and thereby restore the aerobic metabolism provided that neuroimaging analyses reveal the presence of rescuable ischaemic tissue. On January 28-29, 2009, the Journal of Internal Medicine arranged a 2-day symposium entitled Stockholm stroke symposium - from genes to acute care. In this issue of JIM, five comprehensive reviews from this symposium are presented. These include the genetic factors in the aetiology and treatment of ischaemic stroke, the interplay between microvessels, neurons and glia (i.e., the microvascular unit) in the setting of acute stroke, a critical review of various neuroimaging techniques to visualize ischaemic tissue that is still viable (the ischaemic penumbra), recanalization strategies by means of intravenous thrombolysis as well as future recanalization techniques by, for example, intra-arterial or mechanical thrombolysis and sonothrombolysis by a transcranial approach.

Lipid oxidation and peroxidation in CNS health and disease: from molecular mechanisms to therapeutic opportunities

Reactive oxygen species (ROS) are produced at low levels in mammalian cells by various metabolic processes, such as oxidative phosphorylation by the mitochondrial respiratory chain, NAD(P)H oxidases, and arachidonic acid oxidative metabolism. To maintain physiological redox balance, cells have endogenous antioxidant defenses regulated at the transcriptional level by Nrf2/ARE. Oxidative stress results when ROS production exceeds the cell's ability to detoxify ROS. Overproduction of ROS damages cellular components, including lipids, leading to decline in physiological function and cell death. Reaction of ROS with lipids produces oxidized phospholipids, which give rise to 4-hydroxynonenal, 4-oxo-2-nonenal, and acrolein. The brain is susceptible to oxidative damage due to its high lipid content and oxygen consumption. Neurodegenerative diseases (AD, ALS, bipolar disorder, epilepsy, Friedreich's ataxia, HD, MS, NBIA, NPC, PD, peroxisomal disorders, schizophrenia, Wallerian degeneration, Zellweger syndrome) and CNS traumas (stroke, TBI, SCI) are problems of vast clinical importance. Free iron can react with H(2)O(2) via the Fenton reaction, a primary cause of lipid peroxidation, and may be of particular importance for these CNS injuries and disorders. Cholesterol is an important regulator of lipid organization and the precursor for neurosteroid biosynthesis. Atherosclerosis, the major risk factor for ischemic stroke, involves accumulation of oxidized LDL in the arteries, leading to foam cell formation and plaque development. This review will discuss the role of lipid oxidation/peroxidation in various CNS injuries/disorders.

Targeting ischemic penumbra: part I - from pathophysiology to therapeutic strategy

Penumbra is the viable tissue around the irreversibly damaged ischemic core. The purpose of acute stroke treatment is to salvage penumbral tissue and to improve brain function. However, the majority of acute stroke patients who have treatable penumbra are left untreated. Therefore, developing an effective non-recanalizational therapeutics, such as neuroprotective agents, has significant clinical applications. Part I of this serial review on "targeting penumbra" puts special emphases on penumbral pathophysiology and the development of therapeutic strategies. Bioenergetic intervention by massive metabolic suppression and direct energy delivery would be a promising future direction. An effective drug delivery system for this purpose should be able to penetrate BBB and achieve high local tissue drug levels while non-ischemic region being largely unaffected. Selective drug delivery to ischemic stroke penumbra is feasible and deserves intensive research.

Using a distal access catheter in acute stroke intervention with penumbra, merci and gateway. A technical case report

SUMMARY

This technical report describes the successful use of the newly introduced Distal Access Catheter, initially designed to work with the Merci Retrieval System with the Penumbra aspiration system as the main aspiration catheter. Both devices, one a clot retriever and the other a thrombo-aspiration device, can be used and deployed via the same catheter saving time during acute stoke intervention. Moreover, the larger inner diameter of the distal access catheter may allow more effective clot aspiration.

A Citywide Prehospital Protocol Increases Access to Stroke Thrombolysis in Toronto

Background and Purpose— Intravenous tissue plasminogen activator for ischemic stroke is approved for eligible patients who can be treated within a 3-hour window, but treatment rates remain disappointingly low, often <5%. To improve rapid access to stroke thrombolysis in Toronto, Canada, a citywide prehospital acute stroke activation protocol was implemented by the provincial government to transport acute stroke patients directly to one of 3 regional stroke centers, bypassing local hospitals. This comprised a paramedic screening tool, ambulance destination decision rule, and formal memorandum of understanding of system stakeholders. This report describes the initial impact of the activation protocol at our regional stroke center.

Methods— We compared consecutive patients with stroke arriving to our stroke center during the first 4 months of this new triage protocol (February 14 to June 14, 2005) versus the same 4-month period in 2004.

Results— The protocol resulted in an immediate doubling in the number of patients with acute stroke arriving to our regional stroke center within 2.5 hours of symptom onset. We observed a 4-fold increase in patients who were eligible for and treated with tissue plasminogen activator. The tissue plasminogen activator treatment rate for ischemic stroke patients increased from 9.5% to 23.4% ( P =0.01), and one in 2 patients with ischemic stroke arriving within 2.5 hours received thrombolysis during this period (one in 5 of patients with ischemic stroke overall). The median onset-to-needle time for tissue plasminogen activator-treated patients was significantly reduced. Many implementation challenges were identified and addressed.

Conclusions— This prehospital triage was immediately successful in improving tissue plasminogen activator access for patients with ischemic stroke, enabling our center to achieve one of the highest tissue plasminogen activator treatment rates in North America and underscoring the need for coordinated systems of acute stroke care. Sustainability of such an initiative will be dependent on interdisciplinary teamwork, ongoing paramedic training, adequate hospital staffing, bed availability, and repatriation agreements with community hospitals.

Unsuspected coagulopathy rarely prevents IV thrombolysis in acute ischemic stroke

BACKGROUND

American Heart Association/American Stroke Association guidelines recommend initiating treatment with IV tissue plasminogen activator (tPA) in acute ischemic stroke patients without suspected coagulopathy prior to availability of clotting results; however, little or no data support this practice. We sought to identify how often blood clotting abnormalities were responsible for withholding IV tPA at our institution.

METHODS

We conducted a retrospective review of our prospectively acquired Get With the Guidelines Stroke database from January 2003 to April 2008. All patients underwent clinical evaluation by a neurologist, diagnostic neuroimaging, and laboratory testing on admission. We classified patients with absolute contraindications to IV tPA as ineligible, and those with warnings/relative contraindications or potentially treatable factors as potentially eligible.

RESULTS

Of 2,335 considered for analysis, 470 (20.1%) patients presented to our emergency department (ED) within 3 hours. Among these, 147 (31.3%) received IV tPA in our ED, 102 (21.7%) had an absolute contraindication, and 221 (47%) had a reason to consider withholding tPA. Only 30/470 (6.4%) of potential thrombolysis patients were discovered to have international normalized ratio > or =1.7 or platelets < or =100,000/microL, and of these, 28 were suspected a priori due to known coagulopathy from medication or illness. Only 2/470 (0.4%) patients had an unsuspected coagulopathy that ultimately prevented thrombolysis.

CONCLUSIONS

Based on the experience of a large thrombolysis referral center, stroke patients without suspected clotting abnormality can safely begin thrombolytic therapy before clotting results are available. These data support the current practice guidelines, and may reassure clinicians that the benefits of early administration greatly outweigh the risks due to an unsuspected bleeding diathesis.

Remote supervision of IV-tPA for acute ischemic stroke by telemedicine or telephone before transfer to a regional stroke center is feasible and safe

BACKGROUND AND PURPOSE

Because of a shortage of stroke specialists, many outlying or "spoke" hospitals initiate intravenous (IV) thrombolysis using telemedicine or telephone consultation before transferring patients to a regional stroke center (RSC) hub. We analyzed complications and outcomes of patients treated with IV tissue plasminogen activator (tPA) using the "drip and ship" approach compared to those treated directly at the RSC.

METHODS

A retrospective review of our Get With the Guidelines Stroke (GWTG-Stroke) database from 01/2003 to 03/2008 identified 296 patients who received IV tPA within 3 hours of symptom onset without catheter-based reperfusion. GWTG-Stroke definitions for symptomatic intracranial (sICH), systemic hemorrhage, discharge functional status, and destination were applied. Follow-up modified Rankin Score was recorded when available.

RESULTS

Of 296 patients, 181 (61.1%) had tPA infusion started at an outside spoke hospital (OSH) and 115 (38.9%) at the RSC hub. OSH patients were younger with fewer severe strokes than RSC patients. Patients treated based on telestroke were more frequently octogenarians than patients treated based on a telephone consult. Mortality, sICH, and functional outcomes were not different between OSH versus RSC and telephone versus telestroke patients. Among survivors, mean length of stay was shorter for OSH patients but discharge status was similar and 75% of patients walked independently at discharge.

CONCLUSIONS

Outcomes in OSH "drip and ship" patients treated in a hub-and-spoke network were comparable to those treated directly at an RSC. These data suggest that "drip and ship" is a safe and effective method to shorten time to treatment with IV tPA.

Stroke: acute stroke receiving facilities and management

PURPOSE OF REVIEW

Management of ischemic stroke is challenging. No prehospital treatment option exists, and the only approved pharmacologic therapy, that is, systemic thrombolysis, requires brain imaging and initiation of therapy within a narrow therapeutic window. This review provides an overview of recent efforts to optimize management of suspected stroke patients by reducing the interval from symptom onset to reperfusion therapy.

RECENT FINDINGS

There is clear evidence that stroke patients have a favorable outcome when treated with thrombolysis in specialized stroke centers. Data from the European Cooperative Acute Stroke Study-III trial, coupled with improved patient selection by advanced imaging technologies will expand future therapeutic options. However, major obstacles remain in consistently translating scientific advances into clinical practice with only a small percentage of potentially eligible patients receiving thrombolysis. Integrated systems of prehospital management and clinical pathways are necessary to reduce this treatment gap.

SUMMARY

The dogma 'time is brain' is as relevant now as it was at the inauguration of recombinant tissue plasminogen activator for acute stroke treatment in 1996. Knowledge of stroke symptoms and treatment options by the public and first responders, along with integrated stroke systems of care are crucial to ensure rapid access to stroke expertise and treatment.

[Therapy of acute ischemic stroke]

New diagnostic and therapeutic developments have led to an innovative approach to stroke therapy. The slogan "time is brain" emphasizes that stroke is a medical emergency comparable to myocardial infarction. The stroke unit conception is an evidence based therapy for all stroke patients and improves outcome significantly. The monitoring of vital signs and the management of stroke specific complications are highly effective. Early secondary prophylaxis reduces the risk of recurrence. The effect of CT based thrombolysis within the time window of 4,5 h has been substantiated by current data. Stroke MRI holds the promise for an improved therapy by patient stratification and by opening the time window. Interventional recanalisation, vascular interventions and hemicraniectomy complement the therapeutic options in the acute phase of stroke.

Point-of-care international normalized ratio testing accelerates thrombolysis in patients with acute ischemic stroke using oral anticoagulants

BACKGROUND AND PURPOSE

Thrombolysis in patients using oral anticoagulants (OAC) and in patients for whom information on OAC status is not available is frequently delayed because the standard coagulation analysis procedure in central laboratories (CL) is time-consuming. By using point-of-care (POC) coagumeters, international normalized ratio (INR) values can be measured immediately at the bedside. The accuracy and effectiveness of POC devices for emergency management in acute ischemic stroke has not been tested.

METHODS

In phase 1, the reliability of emergency INR POC measurements in comparison to CL was determined. In phase 2, patients with ischemic stroke admitted within the time frame for systemic thrombolysis and who were either using OAC or for whom information on OAC status was not available were enrolled. Patients received thrombolysis if POC INR was <or=1.5. Precision and time gain was recorded for INR as measured by POC vs CL.

RESULTS

In phase 1 (n=113), Bland-Altman analysis showed close agreement between POC and CL, and Pearson correlation was highly significant (r=0.98; P<0.01). In phase 2, 48 patients were included, of whom 70.8% were using OAC; 23 patients received thrombolysis. After subtracting the time needed for the diagnostic work-up, the net time gain was 28+/-12 minutes (mean+/-SD).

CONCLUSIONS

Measuring INR by POC in an emergency setting is sufficiently precise in OAC acute stroke patients and substantially reduces the time interval until INR values are available and therefore may hasten the initiation of thrombolysis.

Delayed recognition of initial stroke in children: need for increased awareness

OBJECTIVE

The goal was to identify the delays involved in diagnosing pediatric arterial ischemic stroke (AIS), a major cause of morbidity and death in children.

METHODS

Neonates (<or=28 days of age) and children with a first presentation of radiologically confirmed AIS between June 1993 and January 2006 were identified retrospectively. The time to diagnosis of AIS (ie, time from clinical onset to radiologic confirmation) was calculated, and factors influencing stroke diagnosis were reviewed.

RESULTS

A total of 107 patients (19 neonates and 88 children) with a diagnosis of AIS were identified. The median time to AIS diagnosis was 87.9 hours for neonates, significantly longer than 24.8 hours for children (P = .0002). Sixty-nine percent of the children with AIS demonstrated a likely cardioembolic cause, and 51 (58%) of the 88 children were inpatients at the time of stroke. The inpatients were seen by a physician more quickly (P < .01) and received a diagnosis of AIS sooner (P < .01). Seventy-six (86%) of the 88 children had a focal neurologic deficit when first seen by a physician. Physicians documented a diagnosis/differential diagnosis for 44 (50%) of 88 children, and they documented a suspicion of AIS for only 23 (26%) of 88 children. The presence of seizures or focal signs was not associated with a quicker time to stroke confirmation.

CONCLUSIONS

The considerable delays in the diagnosis of pediatric AIS are most likely related to the lack of awareness of stroke among medical staff members, despite risk factors and focal signs at presentation.

National Institutes of Health Stroke Scale score is poorly predictive of proximal occlusion in acute cerebral ischemia

BACKGROUND AND PURPOSE

Multimodal imaging is gaining an important role in acute stroke. The benefit of obtaining additional clinically relevant information must be weighed against the detriment of increased cost, delaying time to treatment, and adverse events such as contrast-induced nephropathy. Use of National Institutes of Health Stroke Scale (NIHSS) score to predict a proximal arterial occlusion (PO) is suggested by several case series as a viable method of selecting cases appropriate for multimodal imaging.

METHODS

Six hundred ninety-nine patients enrolled in a prospective cohort study involving CT angiographic imaging in acute stroke were dichotomized according to the presence of a PO, including a subgroup of 177 subjects with middle cerebral artery M1 occlusion.

RESULTS

The median NIHSS score of patients found to have a PO was higher than the overall median (9 versus 5, P<0.0001). The median NIHSS score of patients with middle cerebral artery M1 occlusion was 14. NIHSS score > or =10 had 81% positive predictive value for PO but only 48% sensitivity with the majority of subjects with PO presenting with lower NIHSS scores. All patients with NIHSS score > or =2 would need to undergo angiographic imaging to detect 90% of PO.

CONCLUSIONS

High NIHSS score correlates with the presence of a proximal arterial occlusion in patients presenting with acute cerebral ischemia. No NIHSS score threshold can be applied to select a subgroup of patients for angiographic imaging without failing to capture the majority of cases with clinically important occlusive lesions. The finding of minimal clinical deficits should not deter urgent angiographic imaging in otherwise appropriate patients suspected of acute stroke.

Impact of a telemedicine system on acute stroke care in a community hospital

In January 2007, a telestroke system was established between a community hospital lacking a neurologist on call and a stroke centre 70 km away. The telestroke system allowed urgent remote evaluation of the patient by a specialized neurologist, supervised thrombolytic treatment or a decision for urgent transfer to the stroke centre. During the first year of operation of the telestroke system, we studied all acute ischaemic stroke patients admitted to the community hospital and compared the results with the previous year. Approximately the same number of acute stroke patients were admitted to the community hospital in each year (201 cases in 2006 and 198 in 2007). The telestroke system was activated 75 times in 2007, the number of stroke patients evaluated by a specialized neurologist increased (17% vs. 38%, P > 0.001) and interhospital transfers were reduced (17% vs. 6%, P = 0.001). The number of thrombolytic treatments was doubled: 4.5% ( n = 9) in 2006 vs. 9.6% ( n = 19, 12 of them in the community hospital) in 2007 ( P = 0.073). The telestroke system also reduced the time to tPA treatment from symptom onset (210 vs. 162 min, P = 0.05) and increased the number of patients treated in the 0–3 hours window (40% vs. 63%, P = 0.09). Telemedicine improved the quality of care administered to acute stroke patients admitted to a community hospital and reduced the number of inter-hospital transfers.

Aggregation of marginal gains in the care of acute stroke

The chain of events between a patient first suffering symptoms of acute ischaemic stroke and receiving treatment in an acute stroke unit contains the potential for many delays. Identifying and minimizing these delays can make the difference between life and death, serious debilitation and complete recovery.

Number needed to treat to benefit and to harm for intravenous tissue plasminogen activator therapy in the 3- to 4.5-hour window: joint outcome table analysis of the ECASS 3 trial

BACKGROUND AND PURPOSE

Measures of a therapy's effect size are important guides to clinicians, patients, and policy-makers on treatment decisions in clinical practice. The ECASS 3 trial demonstrated a statistically significant benefit of intravenous tissue plasminogen activator for acute cerebral ischemia in the 3- to 4.5-hour window, but an effect size estimate incorporating benefit and harm across all levels of poststroke disability has not previously been derived.

METHODS

Joint outcome table specification was used to derive number needed to treat to benefit (NNTB) and number needed to treat to harm (NNTH) values summarizing treatment impact over the entire outcome range on the modified Rankin scale of global disability, including both expert-dependent and expert-independent (algorithmic and repeated random sampling) array generation.

RESULTS

For the full 7-category modified Rankin scale, algorithmic analysis demonstrated that the NNTB for 1 additional patient to have a better outcome by >or=1 grades than with placebo must lie between 4.0 and 13.0. In bootstrap simulations, the mean NNTB was 7.1. Expert joint outcome table analyses indicated that the NNTB for improved final outcome was 6.1 (95% CI, 5.6-6.7) and the NNTH 37.5 (95% CI, 34.6-40.5). Benefit per 100 patients treated was 16.3 and harm per 100 was 2.7. The likelihood of help to harm ratio was 6.0.

CONCLUSIONS

Treatment with tissue plasminogen activator in the 3- to 4.5-hour window confers benefit on approximately half as many patients as treatment <3 hours, with no increase in the conferral of harm. Approximately 1 in 6 patients has a better and 1 in 35 has a worse outcome as a result of therapy.

C-arm CT measurement of cerebral blood volume: an experimental study in canines

BACKGROUND AND PURPOSE

Cerebral blood volume (CBV) is an important parameter in estimating the viability of brain tissue following an ischemic event. We tested the hypothesis that C-arm CT measurements of CBV would correlate well with those made with perfusion CT (PCT).

MATERIALS AND METHODS

CBV was measured in 12 canines by using PCT and C-arm CT. Two measurements with each technique were made on each animal; a different injection protocol was used for each of these techniques. PCT was performed by using a 64-section V-scanner. C-arm CT was performed by using a biplane Artis dBA system. PCT images were transferred to a commercially available workstation for postprocessing and analysis; C-arm CT images were transferred to a commercially available workstation for postprocessing and analysis by using prototype software. From each animal, 2 sections from each technique were selected for analysis.

RESULTS

There was good agreement of both the color maps and absolute numbers between the 2 techniques. The maximum and mean deviations of values between the 2 techniques for the first 5 animals were 30.20% and 7.82%; for the second 7 animals, these values were 26.79% and 7.40%. The maximum and mean deviations between the 2 C-arm CT studies performed on the first 5 animals were 33.15% and 12.24%; for the second 7 animals, these values were 41.15% and 10.89%.

CONCLUSIONS

In these healthy animals, measurement of CBV with C-arm CT compared well with measurements made with PCT.

A prospective study of the time to evacuate acute subdural and extradural haematomas

We performed a prospective, single-centre study of times to treatment of patients with life-threatening, traumatic, extra- and subdural haematomas requiring surgical evacuation between May 2006 and May 2007. The mean time to surgical decompression was 5.0 h and 32% were performed within 4 h. Patients who initially presented to a district hospital and required transfer for neurosurgery were decompressed in 5.4 h vs 3.7 h for those admitted directly. The current standard of surgical evacuation of all haematomas within 4 h is not being met. Delays were identified in every stage in the management of these patients and no single step was identified as the major cause. Initial treatment in district hospitals led to delays greater than the added driving time. There may be time savings from carrying out treatment steps in parallel instead of in series.

Is the drip-and-ship approach to delivering thrombolysis for acute ischemic stroke safe?

BACKGROUND

The drip-and-ship method of treating stroke patients may increase the use of tissue plasminogen activator (t-PA) in community hospitals.

OBJECTIVE

The safety and early outcomes of patients treated with t-PA for acute ischemic stroke (AIS) by the drip-and-ship method were compared to patients directly treated at a stroke center.

METHODS

The charts of all patients who were treated with intravenous (i.v.) t-PA at outside hospitals under the remote guidance of our stroke team and were then transferred to our facility were reviewed. Baseline NIHSS (National Institutes of Health Stroke Scale) scores, onset-to-treatment (OTT), and arrival-to-treatment (ATT) times were abstracted. The rates of in-hospital mortality, symptomatic hemorrhage (sICH), early excellent outcome (modified Rankin Scale [mRS] ≤ 1), and early good outcome (discharge home or to inpatient rehabilitation) were determined.

RESULTS

One hundred sixteen patients met inclusion criteria. Eighty-four (72.4%) were treated within 3 h of symptom onset. The median estimated NIHSS score was 9.5 (range 3-27). The median OTT time was 150 min, and the median ATT was 85 min. These patients had an in-hospital mortality rate of 10.7% and sICH rate of 6%. Thirty percent of patients had an early excellent outcome and 75% were discharged to home or inpatient rehabilitation. When these outcome rates were compared with those observed in patients treated directly at our stroke center, there were no statistical differences.

CONCLUSIONS

In this small retrospective study, drip-and-ship management of delivering i.v. t-PA for AIS patients did not seem to compromise safety. However, a large prospective study comparing drip-and-ship management to routine care is needed to validate the safety of this approach to treatment.

Neuroimaging of ischemic stroke with CT and MRI: advancing towards physiology-based diagnosis and therapy

Acute ischemic stroke is the third leading cause of death and the major cause of significant disability in adults in the USA and Europe. The number of patients who are actually treated for acute ischemic stroke is disappointingly low, despite availability of effective treatments. A major obstacle is the short window of time following stroke in which therapies are effective. Modern imaging is able to identify the ischemic penumbra, a key concept in stroke physiology. Evidence is accumulating that identification of a penumbra enhances patient management, resulting in significantly improved outcomes. Moreover, unexpectedly large proportions of patients have a substantial ischemic penumbra beyond the traditional time window and are suitable for therapy. The widespread availability of modern MRI and computed tomography systems presents new opportunities to use physiology to guide ischemic stroke therapy in individual patients. This article suggests an evidence-based alternative to contemporary acute ischemic stroke therapy.

Novel thrombolytic drugs: will they make a difference in the treatment of ischaemic stroke?

Treatment of acute ischaemic stroke aims to recanalize the occluded artery, salvage the at-risk brain tissue and thus minimize neurological sequelae. Efforts a decade ago have led to the only currently approved medical treatment for acute ischaemic stroke, i.e. intravenous alteplase given within 3 hours of stroke onset. Recanalization occurs in only one-half of the patients receiving alteplase, and only approximately 5% of all ischaemic stroke patients in industrialized countries receive this treatment. Studies are currently being carried out to determine whether intravenous alteplase would be safe and effective for up to 4.5 hours after ischaemic stroke onset, and whether it should be followed by an intra-arterial approach. Two novel thrombolytic drugs being studied for acute ischaemic stroke are desmoteplase and tenecteplase. Although the first trials were promising, the most recent evidence suggests that desmoteplase is not superior to placebo, even in carefully selected patients, in the 3- to 9-hour time window after stroke onset. Tenecteplase has only been studied for acute ischaemic stroke in a single noncontrolled, dose-finding trial in the 3-hour time window after stroke onset, which suggested a similar efficacy to that demonstrated in the historical data from the alteplase trials. A trial to compare the safety and efficacy of tenecteplase versus alteplase is ongoing. Safer and more effective thrombolytic drugs for the treatment of ischaemic stroke are thus being sought. Such agents will be welcome, but they are not here yet. While waiting we are likely to see the emergence of additive therapies, including ultrasound insonation, neuroprotective/regenerative agents and invasive intra-arterial techniques. Novel thrombolytic drugs, or other novel therapies, possess great potential to make a difference in the future, but the most urgent priority now is in the organization of stroke treatment in such a way that more patients receive the currently available optimal treatments.

Does study enrollment delay treatment with intravenous thrombolytics for acute ischemic stroke?

BACKGROUND AND PURPOSE

Enrollment in acute stroke trials at a stroke center with multiple study protocols may delay the initiation of intravenous thrombolytics in patients who present within 3 hours of symptom onset.

METHODS

We studied all patients presenting with acute ischemic stroke over the past 3.5 years who qualified for thrombolysis within 3 hours of symptom onset. We collected demographics, baseline National Institutes of Health Stroke Scale scores, CT findings, and arrival-to-treatment times and compared patients treated with intravenous thrombolytics in a clinical trial with patients who received standard of care intravenous tissue plasminogen activator.

RESULTS

Of 290 treated patients, 19 were enrolled in prelytic studies, 46 were enrolled in postlytic studies, and 225 were treated with standard intravenous tissue plasminogen activator. There was no significant difference in age, gender, National Institutes of Health Stroke Scale score, admission glucose, or changes on CT. There was no difference in onset-to-arrival time or arrival-to-treatment time between patients enrolled in clinical studies and those who received standard treatment. However, among study patients, prelytic randomization led to a significantly longer arrival-to-treatment time by 13 minutes (P=0.028).

CONCLUSIONS

We found that trials requiring prethrombolytic randomization can lead to a delay in the initiation of treatment. Future studies are needed to determine if such a delay is clinically significant and can be shortened by improved enrollment strategies.

Efficacy of site-independent telemedicine in the STRokE DOC trial: a randomised, blinded, prospective study

BACKGROUND

To increase the effective use of thrombolytics for acute stroke, the expertise of vascular neurologists must be disseminated more widely. We prospectively assessed whether telemedicine (real-time, two-way audio and video, and digital imaging and communications in medicine [DICOM] interpretation) or telephone was superior for decision making in acute telemedicine consultations.

METHODS

From January, 2004, to August, 2007, patients older than 18 years who presented with acute stroke symptoms at one of four remote spoke sites were randomly assigned, through a web-based, permuted blocks system, to telemedicine or telephone consultation to assess their suitability for treatment with thrombolytics, on the basis of standard criteria. The primary outcome measure was whether the decision to give thrombolytic treatment was correct, as determined by central adjudication. Secondary outcomes were the rate of thrombolytic use, 90-day functional outcomes (Barthel index [BI] and modified Rankin scale [mRS]), the incidence of intracerebral haemorrhages, and technical observations. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00283868.

FINDINGS

234 patients were assessed prospectively. 111 patients were randomised to telemedicine, and 111 patients were randomised to telephone consultation; 207 completed the study. Mean National Institutes of Health stroke scale score at presentation was 9.5 (SD 8.1) points (11.4 [8.7] points in the telemedicine group versus 7.7 [7.0] points in the telephone group; p=0.002). One telemedicine consultation was aborted for technical reasons, although it was included in the analyses. Correct treatment decisions were made more often in the telemedicine group than in the telephone group (108 [98%] vs 91 [82%], odds ratio [OR] 10.9, 95% CI 2.7-44.6; p=0.0009). Intravenous thrombolytics were used at an overall rate of 25% (31 [28%] telemedicine vs 25 [23%] telephone, 1.3, 0.7-2.5; p=0.43). 90-day functional outcomes were not different for BI (95-100) (0.6, 0.4-1.1; p=0.13) or for mRS score (0.6, 0.3-1.1; p=0.09). There was no difference in mortality (1.6, 0.8-3.4; p=0.27) or rates of intracerebral haemorrhage after treatment with thrombolytics (2 [7%] telemedicine vs 2 [8%] telephone, 0.8, 0.1-6.3; p=1.0). However, there were more incomplete data in the telephone group than in the telemedicine group (12%vs 3%, 0.2, 0.1-0.3; p=0.0001).

INTERPRETATION

The authors of this trial report that stroke telemedicine consultations result in more accurate decision making compared with telephone consultations and can serve as a model for the effectiveness of telemedicine in other medical specialties. The more appropriate decisions, high rates of thrombolysis use, improved data collection, low rate of intracerebral haemorrhage, low technical complications, and favourable time requirements all support the efficacy of telemedicine for making treatment decisions, and might enable more practitioners to use this medium in daily stroke care.

Glycoprotein IIb/IIIa antagonists in acute ischaemic stroke: current status and future directions

Glycoprotein (GP) IIb/IIIa receptors on the surface of platelets play a critical role in thrombosis. Intravenous GP IIb/IIIa antagonists abciximab, tirofiban and eptifibatide have demonstrated efficacy in acute coronary syndromes when combined with heparin, aspirin, clopidogrel and percutanous coronary interventions. Results have been less consistent in acute ischaemic stroke. Preclinical data support the potential benefit of these agents both in the microcirculation and in aiding clot lysis. While phase I and II trials of abciximab as the sole agent employing dosages comparable with those used in coronary syndromes were promising, the pivotal phase III trial was abandoned because of an unfavourable benefit-to-risk ratio. New preliminary platelet inhibition measurements from our group suggest that cardiac dosages were likely to be too high for stroke patients. Exploration of lower dosages of abciximab and potentiation with time-limited weight-based heparin along with platelet aggregation inhibition measurement is continuing on a smaller scale. At present, the most common usage of GP IIb/IIIa antagonists in stroke are as adjunctive agents to thrombolysis by intravenous and intra-arterial routes. Substantial progress is likely to require a better understanding of the mechanism of actions and unique pharmacology of GP IIb/IIIa antagonists in ischaemic stroke.

Aggressive blood pressure-lowering treatment before intravenous tissue plasminogen activator therapy in acute ischemic stroke

BACKGROUND

Patients with acute ischemic stroke (AIS) commonly have elevated blood pressure (BP). Guidelines have recommended against treatment with intravenous tissue plasminogen activator (tPA) when aggressive measures such as continuous infusion with nicardipine hydrochloride are required to maintain BP lower than 185/110 mm Hg. We evaluated the effect of elevated BP and its management on clinical outcomes after tPA therapy in AIS.

OBJECTIVES

To evaluate safety and outcome in patients with AIS who require treatment to lower BP before tPA therapy and to compare safety and outcome in patients who received aggressive treatment with nicardipine with those who received labetalol hydrochloride before tPA.

DESIGN

Retrospective review of medical records for all patients who received intravenous tPA within 3 hours of AIS onset.

SETTING

Emergency department. Patients One hundred seventy-eight patients with AIS treated with tPA.

MAIN OUTCOME MEASURES

Occurrence of symptomatic intracerebral hemorrhage and neurologic deterioration.

RESULTS

Fifty patients required BP lowering before tPA therapy. Twenty-four of these patients (48%) received nicardipine either after labetalol or as first-line therapy. Patients requiring antihypertensive agents had higher baseline blood glucose concentrations, incidence of hypertension, and National Institutes of Health Stroke Scale scores. The rate of adverse events and of modified Rankin score at discharge were not significantly different in patients without BP-lowering treatment compared with patients given either labetalol or nicardipine before intravenous tPA therapy.

CONCLUSIONS

Blood pressure lowering before intravenous tPA therapy, even using aggressive measures, may not be associated with a higher rate of hemorrhage or poor outcome. Data suggest that patients with AIS requiring aggressive treatment to lower BP should not be excluded from receiving tPA therapy. A prospective study is needed to support these conclusions.

Renal safety of CT angiography and perfusion imaging in the emergency evaluation of acute stroke

BACKGROUND AND PURPOSE

Multimodal CT imaging with contrast-enhanced CT angiography (CTA) and CT perfusion (CTP) is increasingly being used to guide emergency management of acute stroke. However, little has been reported about the safety of intravenous contrast administration associated with these studies in the acute stroke population, including cases in which baseline creatinine values are unknown. We investigated the incidence of contrast-induced nephropathy (CIN), defined as a 25% or more increase in baseline creatinine levels within 72 hours of contrast administration and chronic kidney disease in patients receiving CTA+/-CTP at our regional stroke center.

MATERIALS AND METHODS

We analyzed 198 patients who underwent contrast CT studies for evaluation of acute ischemic or hemorrhagic stroke at our center (2003-2007). Through retrospective chart abstraction, we analyzed serial creatinine levels (baseline to day 3) and later values (>/=day 4) where available. The incidences of CIN and/or chronic kidney disease were documented. After power analysis, CIN and non-CIN groups were compared by using the unpaired t test, Wilcoxon rank sum test, or Fisher exact test.

RESULTS

None of the 198 patients developed chronic kidney disease or required dialysis. Of 175 patients with serial creatinine measurements between baseline and day 3, 5 (2.9%) developed CIN. The incidence of CIN was 2% in patients who were scanned before a baseline creatinine level was available.

CONCLUSION

The incidence of renal sequelae is relatively low in acute stroke patients undergoing emergent multimodal CT scanning. Prompt CTA/CTP imaging of acute stroke, if indicated, need not be delayed in those with no history of renal impairment.

“Current Pathology Techniques” Symposium Review: Advances and Issues in Neuropathology

Our understanding of the mechanisms that incite neurological diseases has progressed rapidly in recent years, mainly owing to the advent of new research instruments and our increasingly facile ability to assemble large, complex data sets acquired across several disciplines into an integrated representation of neural function at the molecular, cellular, and systemic levels. This mini-review has been designed to communicate the principal technical advances and current issues of importance in neuropathology research today in the context of our traditional neuropathology practices. Specific topics briefly addressed in this paper include correlative biology of the many facets of the nervous system; conventional and novel methods for investigating neural structure and function; theoretical and technical issues associated with investigating neuropathology end points in emerging areas of concern (developmental neurotoxicity, neurodegenerative conditions); and challenges and opportunities that will face pathologists in this field in the foreseeable future. We have organized this information in a manner that we hope will be of interest not only to professionals with a career focus in neuropathology, but also to general pathologists who occasionally face neuropathology questions.