The STRokE DOC Trial Technique: ‘Video Clip, Drip, and/or Ship’

Rationale

To describe the clinical trial methods of a site-independent telemedicine system used in stroke.

Aims

A lack of readily available stroke expertise may partly explain the low rate of rt-PA use in acute stroke. Although telemedicine systems can reliably augment expertise available to rural settings, and may increase rt-PA use, point-to-point systems do require fixed base stations. Site-independent systems may minimize delay. The STRokE DOC trial assesses whether site-independent telemedicine effectively and efficiently brings rt-PA to a remote population.

Design

STRokE DOC is a 5–year, 400–participant, noninvasive trial, comparing two consultative techniques at four remote sites. Participants are randomized to acute ‘STRokE DOC telemedicine’ or ‘telephone’ consultations. Treatment decision accuracy is adjudicated at two time points, using three levels of data availability and an independent auditor.

Study outcomes

The primary outcome measure is whether there was a ‘correct decision to treat or not to treat using rt-PA’ at each of three adjudication levels (primarily at Level #2). Secondary outcomes include the number of thrombolytic recommendations, intracerebral hemorrhage, and 90–day outcomes. Using the STRokE DOC system (or telephone evaluation), medical history, neurologic scales, CT interpretations, and recommendations have been completed on over 200 participants to date. Of the initial 11, nonrandomized, ‘run-in’ patients, six (65%) were evaluated wirelessly, and five (45%) were evaluated with a site-independent LAN or cable modem. Three (27%) received rt-PA. The adjudication methodology was able to show both agreements and disagreements in these 11 cases. It is feasible to perform site-independent stroke consultations, and adjudicate those cases, using the STRokE DOC system and trial design. Telemedicine efficacy remains to be proven.

Production and validation of Putonghua- and Cantonese-Chinese language National Institutes of Health Stroke Scale training and certification videos

BACKGROUND AND PURPOSES

The National Institutes of Health Stroke Scale (NIHSS) is an integral part of acute stroke assessment. We report our experience with new Putonghua- and Cantonese-Chinese language NIHSS (PC-NIHSS and CC-NIHSS) training and certification videos.

METHODS

A professional video production company was hired to create the training and certification videos for both PC-NIHSS and CC-NIHSS. Two training and certification workshops were held in Chengdu and Beijing, and two workshops in Hong Kong. The instruction, training and group A certification videos were presented to workshop attendees. Unweighted kappa statistics were used to measure the agreement among raters, and the inter-rater agreements for PC-NIHSS and CC-NIHSS videos were compared with those of original English language NIHSS (E-NIHSS) videos.

RESULTS

The pass rates using PC-NIHSS and CC-NIHSS videos were 79% and 82%, respectively. All possible responses on individual scale items were included. Facial palsy and limb ataxia (13%) showed poor agreement, nine (60%) to 10 (67%) items showed moderate agreement (0.4<kappa<0.75), and three (20%) to four (27%) items showed excellent agreement. When compared with E-NIHSS videos, the agreements on best gaze, visual fields, facial weakness and aphasia were less for PC-NIHSS videos, and the agreements on commands for level of consciousness and visual fields were less for CC-NIHSS videos. Nevertheless, there was no difference between PC-NIHSS or CC-NIHSS and E-NIHSS videos in the agreement on total score.

CONCLUSIONS

Compared with E-NIHSS videos, PC-NIHSS and CC-NIHSS videos show good content validity and inter-rater reliability. Availability of these videos may facilitate the proper use of NIHSS among physicians and nurses in Putonghua- or Cantonese-speaking communities.

The modified National Institutes of Health Stroke Scale: its time has come

The National Institutes of Health Stroke Scale (NIHSS) is a well known, reliable and valid stroke deficit scale. The NIHSS is simple, quick, and has shown significant reliability in diverse groups, settings, and languages. The NIHSS also contains items with poor reliability and redundancy. Recent investigations (include assessing a new training DVD, analyzing webbased or videotape certifications, and testing foreign language versions) have further detailed reliability issues. Items recurrently shown to have poor reliability include Level of Consciousness, Facial Palsy, Limb Ataxia, and Dysarthria. The modified NIHSS (mNIHSS) minimizes redundancy and eliminates poorly reliable items. The mNIHSS shows greater reliability in multiple settings and cohorts, including scores abstracted from records, when used via telemedicine, and when used in clinical trials. In a validation of the mNIHSS against the NIHSS, the number of elements with excellent agreement increased from 54% to 71%, while poor agreement decreased from 12% to 5%. Overall, 45% of NIHSS items had less than excellent reliability vs. only 29% for the mNIHSS. The mNIHSS is not the ideal stroke scale, but it is a significant improvement over the NIHSS. The mNIHSS has shown reliability at bedside, with record abstraction, with telemedicine, and in clinical trials. Since the mNIHSS is more reliable, it may allow for improved practitioner communication, improved medical care, and refinement of trial enrollments. The mNIHSS should now serve as the primary stroke clinical deficit scale for clinical and research aims. When it comes to the mNIHSS, its time has come!

Prior antiplatelet use does not affect hemorrhage growth or outcome after ICH

OBJECTIVE

To examine whether antiplatelet medication use at onset of intracerebral hemorrhage (ICH) is associated with hemorrhage growth and outcome after spontaneous ICH using a large, prospectively collected database from a recent clinical trial.

METHODS

The Cerebral Hemorrhage and NXY-059 Treatment trial was a randomized, placebo-controlled trial of NXY-059 after spontaneous ICH. We analyzed patients in the placebo arm, and correlated antiplatelet medication use at the time of ICH with initial ICH volumes, ICH growth in the first 72 hours, and modified Rankin Score at 90 days. Patients on oral anticoagulation were excluded.

RESULTS

There were 282 patients included in this analysis, including 70 (24.8%) who were taking antiplatelet medications at ICH onset. Use of antiplatelet medications at ICH onset had no association with the volume of ICH at presentation, growth of ICH at 72 hours, initial edema volume, or edema growth. In multivariable analysis, there was no association of use of antiplatelet medications with any hemorrhage expansion (relative risk [RR] 0.85 [upper limit of confidence interval (UCI) 1.03], p = 0.16), hemorrhage expansion greater than 33% (RR 0.77 [UCI 1.18], p = 0.32), or clinical outcome at 90 days (odds ratio 0.67, 95% confidence interval 0.39-1.14, p = 0.14).

CONCLUSIONS

Use of antiplatelet medications at intracerebral hemorrhage (ICH) onset is not associated with increased hemorrhage volumes, hemorrhage expansion, or clinical outcome at 90 days. These findings suggest that attempts to reverse antiplatelet medications after ICH may not be warranted.

Quantitative effects of nefiracetam on spatial learning of rats after cerebral embolism

Recent studies have shown that nefiracetam ameliorates cognitive dysfunction because of ischemia when behavioral testing occurs during treatment. We sought to determine if there was a persistent effect after treatment, by testing spatial learning of embolized rats after nefiracetam therapy.

METHODS

Male Sprague Dawley rats (250 to 300 g) were divided into 3 categories. The control group (n = 5) underwent no surgery or cerebral embolism. The vehicle group (n = 12) was anesthetized with halothane, underwent surgery, injected with intracarotid microspheres, and given orally 5 mL/kg of the vehicle (0.5% aqueous sodium carboxymethyl cellulose) for 21 days. The nefiracetam group (n = 12) was embolized and treated orally with 30 mg/kg nefiracetam (6 mg/mL in vehicle) for 21 days. Outcome was determined with visual spatial learning after the end of treatment.

RESULTS

Embolization caused a significant impairment in visual spatial learning, which nefiracetam completely ameliorated (group main effect, F(2,444) = 6.4, P = .002). Mean latency to the escape was 35 +/- 6 seconds for the vehicle group versus 18 +/- 4 seconds for the nefiracetam group, after 4 days of testing. This effect persisted after a further interval of 10 days (retention test). A reversal test (to assess working memory for new information) yielded mean latencies of 26 +/- 6 seconds for the control group, 49 +/- 5 seconds for vehicle, and 25 +/- 4 seconds for nefiracetam (group main effect, F(2,109) = 8.0, P = .0005, Newman-Keuls, P < .05), showing that both the control and nefiracetam groups were different from the vehicle group.

CONCLUSION

Nefiracetam therapy improves the learning behavior of embolized rats. The results are not caused by an activating effect of the drug because the animals are tested after the treatment period is over and because the beneficial effect is seen using the delayed retention test. Finally, working memory is markedly preserved by nefiracetam, an effect observed several weeks after treatment.

Recent advances in stroke management

Major advances in stroke treatment and prevention have, occurred over the last several years. Recent studies have documented that appropriate modification of stroke risk factors can lead to, a substantial reduction in stroke incidence. In addition, a variety of new risk factors, such as elevated plasma homocysteine levels, antiphospholipid antibodies, and specific genetic factors, are being recognized. The most significant advance in acute stroke therapy is the use of intravenous tissue plasminogen activator, (t-PA) for treatment of patients with ischemic stroke within 3 hours of symptom onset. T-PA is currently the only stroke treatment approved by the Federal Drug Administration. There continues to be uncertainty and misunder-standing regarding the risks and benefits of this therapy. A variety of neuroprotective agents have been highly successful for reducing ischemic brain injury in animal stroke models. Recent clinical trials with these agents, however, have not produced beneficial effects in humans. Newer neuroprotective agents with more favorable safety profiles and improvements in clinical trial design may lead to therapeutic successes in the near future. It is apparent that both thrombolytic and neuroprotective treatments for acute stroke must be administered very rapidly, after stroke onset. Therefore, acute stroke teams are being developed to facilitate rapid diagnostic evaluation and treatment of stroke patients.

Real-time cerebral angiography: sensitivity of a new contrast-specific ultrasound technique

BACKGROUND AND PURPOSE

To test a new contrast-specific sonography imaging method that offers visualization of the intracranial vasculature in a manner similar to that seen on angiography.

MATERIALS AND METHODS

Thirty patients (35 sonography studies total) were included in the study after they provided written informed consent. The patients were scanned through the temporal bone window from both sides after intravenous injection of an ultrasound contrast agent (UCA; perflexane lipid microspheres [Imagent]). The goal was to visualize the intracranial arteries, including the middle (M1-M3), anterior (A1 and A2), and posterior (P1-P3) cerebral arteries, using an axial scanning plane. The studies were performed using a contrast-specific imaging mode, based on a phase inversion technique (transcranial ultrasound angiography [tUSA]). For sensitivity, the results were compared with x-ray angiography as the "gold standard." For interobserver reliability, 24 of 35 sonography studies were evaluated by 2 physicians with little training in transcranial sonography and by a seasoned sonographer.

RESULTS

The sensitivity of tUSA ranged between 0.778 (95% confidence interval [CI] of 0.577-0.914) and 0.963 (95% CI of 0.810-0.999). The sensitivities were similar among physicians with little training in transcranial sonography and the seasoned sonographer, indicating high inter-rater reliability. Overall, tUSA provided high anatomic resolution and vascular delineation even of small vessels in the millimeter range. At peak intensity, no UCA-related artifacts were observed.

CONCLUSION

tUSA provides images of the intracranial arteries similar to those obtained at angiography with high anatomic resolution, reasonable sensitivity, and interobserver reliability.

Prospective reliability of the STRokE DOC wireless/site independent telemedicine system

The authors evaluated a site-independent telemedicine system. Telemedicine may be limited by the need for fixed connectivity. Wireless and site-independent technologies eliminate this limitation. Twenty-five stroke patients underwent evaluations by remote and bedside examiners. Ten of 15 (67%) NIH Stroke Scale and 9 of 11 (82%) Modified NIH Stroke Scale items showed excellent interrater reliability. Spearman correlations were > or =0.93. This Internet system is reliable and valid. Further studies should assess its use in acute stroke.

Lack of hemispheric dominance for consciousness in acute ischaemic stroke

BACKGROUND

Previous reports have suggested left hemispheric dominance for maintaining consciousness, although there is controversy over this claim.

OBJECTIVE

To compare early impairment of level of consciousness between patients with right and left hemispheric stroke.

METHODS

Data from 564 patients with ischaemic stroke enrolled in the placebo arm of a trial of a putative neuroprotectant were analysed. All patients had major hemispheric stroke with cortical dysfunction, visual field deficit, and limb weakness, with symptom onset within 12 hours of enrolment. Patients were prospectively evaluated on a predefined scale (1-6; 1 = fully awake, higher scores representing greater impairment) to measure level of consciousness at multiple time points over the initial 24 hours after presentation. The National Institutes of Health (NIH) stroke scale score at presentation and infarct volume at 30 days were determined.

RESULTS

Some degree of impairment in level of consciousness was observed in 409 of the 564 patients (73%). Median maximum sedation score was 2 for both right and left hemispheric stroke (p = 0.91). Mean sedation score over 24 hours was 1.5 for both right and left stroke (p = 0.75). There was no difference between level of consciousness scores in right and left stroke at any individual time point during the 24 hour monitoring period. No association between side and impairment in level of consciousness was seen after adjustment for stroke severity and infarct volume.

CONCLUSIONS

In contrast to previous reports, there was no evidence for hemispheric dominance for consciousness in the setting of a major hemispheric stroke.

Admission glucose level and clinical outcomes in the NINDS rt-PA Stroke Trial

BACKGROUND

Hyperglycemia during acute ischemic stroke may augment brain injury, predispose to intracerebral hemorrhage (ICH), or both.

METHOD

To analyze the relationship between admission glucose level and clinical outcomes from acute ischemic stroke, the authors performed multivariate regression analysis with the National Institute of Neurological Disorders and Stroke recombinant tissue plasminogen activator (rt-PA) Stroke Trial data. Neurologic improvement was defined as improvement on the NIH Stroke Scale by 4 or more points from baseline to 3 months, or a final score of zero. Favorable outcome was defined as both Glasgow Outcome score of 1 and Barthel Index 95 to 100 at 3 months. Symptomatic ICH was defined as CT-documented hemorrhage temporally related to clinical deterioration within 36 hours of treatment. Potential confounding factors were controlled, including acute treatment (rt-PA or placebo), age, baseline NIH Stroke Scale score, history of diabetes mellitus, stroke subtype, and admission blood pressure.

RESULTS

There were 624 patients enrolled within 3 hours after stroke onset. As admission glucose increased, the odds for neurologic improvement decreased (odds ratio [OR] = 0.76 per 100 mg/dL increase in admission glucose, 95% CI 0.61 to 0.95, p = 0.01). The relation between admission glucose and favorable outcome depended on admission mean blood pressure (MBP): as admission MBP increased, the odds for favorable outcome related to increasing admission glucose levels progressively decreased (p = 0.02). As admission glucose increased, the odds for symptomatic ICH also increased (OR = 1.75 per 100 mg/dL increase in admission glucose, 95% CI 1.11 to 2.78, p = 0.02). Admission glucose level was not associated with altered effectiveness of rt-PA.

CONCLUSIONS

In patients with acute ischemic stroke, higher admission glucose levels are associated with significantly lower odds for desirable clinical outcomes and significantly higher odds for symptomatic ICH, regardless of rt-PA treatment. Whether this represents a cause and effect relationship remains to be determined.

Lack of clinical significance of early ischemic changes on computed tomography in acute stroke

CONTEXT

The prevalence and clinical significance of early ischemic changes (EICs) on baseline computed tomography (CT) scan of the head obtained within 3 hours of ischemic stroke are not established.

OBJECTIVE

To determine the frequency and significance of EIC on baseline head CT scans in the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA (recombinant tissue plasminogen activator) Stroke Trial.

DESIGN AND SETTING

The original study, a randomized controlled trial, took place from January 1991 through October 1994 at 43 sites, during which CT images were obtained within 3 hours of symptom onset and prior to the initiation of rt-PA or placebo. For the current analysis, detailed reevaluation was undertaken after October 1994 of all baseline head CT scans with clinical data available pretreatment (blinded to treatment arm).

PATIENTS

Of 624 patients enrolled in the trial, baseline CT scans were retrieved and reviewed for 616 (99%).

MAIN OUTCOME MEASURES

Frequency of EICs on baseline CT scans; association of EIC with other baseline variables; effect of EICs on deterioration at 24 hours (>/=4 points increase from the baseline National Institutes of Health Stroke Scale [NIHSS] score); clinical outcome (measured by 4 clinical scales) at 3 months, CT lesion volume at 3 months, death at 90 days; and symptomatic intracranial hemorrhage (ICH) within 36 hours of treatment.

RESULTS

The prevalence of EIC on baseline CT in the combined rt-PA and placebo groups was 31% (n = 194). The EIC was significantly associated with baseline NIHSS score (rho = 0.23; P<.001) and time from stroke onset to baseline CT scan (rho = 0.11; P =.007). After adjusting for baseline variables, there was no EIC x treatment interaction detected for any clinical outcome, including deterioration at 24 hours, 4 clinical scales, lesion volume, and death at 90 days (P>/=.25), implying that EIC is unlikely to affect response to rt-PA treatment. After adjusting for NIHSS score (an independent predictor of ICH), no EIC association with symptomatic ICH at 36 hours was detected in the group treated with rt-PA (P>/=.22).

CONCLUSIONS

Our analysis suggests that EICs are prevalent within 3 hours of stroke onset and correlate with stroke severity. However, EICs are not independently associated with increased risk of adverse outcome after rt-PA treatment. Patients treated with rt-PA did better whether or not they had EICs, suggesting that EICs on CT scan are not critical to the decision to treat otherwise eligible patients with rt-PA within 3 hours of stroke onset.

Angiogenesis after stroke is correlated with increased numbers of macrophages: the clean-up hypothesis

Brain cells manufacture and secrete angiogenic peptides after focal cerebral ischemia, but the purpose of this angiogenic response is unknown. Because the maximum possible regional cerebral blood flow is determined by the quantity of microvessels in each unit volume, it is possible that angiogenic peptides are secreted to generate new collateral channels; other possibilities include neuroprotection, recovery/regeneration, and removal of necrotic debris. If the brain attempts to create new collaterals, microvessel density should increase significantly after ischemia. Conversely, if angiogenic-signaling molecules serve some other purpose, microvessel densities may increase slightly or not at all. To clarify, the authors measured microvessel densities with quantitative morphometry. Left middle cerebral arteries of adult male Sprague-Dawley rats were occluded with intraluminal nylon suture for 4 hours followed by 7, 14, 19, or 30 days of reperfusion. Controls received no surgery or suture occlusion. Changes in microvessel density and macrophage numbers were measured by light microscopic morphometry using semiautomated stereologic methods. Microvessel density increased only in the ischemic margin adjacent to areas of pannecrosis and was always associated with increased numbers of macrophages. Ischemic brain areas without macrophages displayed no vascularity changes compared with normal animals. These data suggest that ischemia-induced microvessels are formed to facilitate macrophage infiltration and removal of necrotic brain.

Use of image analysis for estimation of the numerical densities of neurons and synapses in cerebral cortex

Relating to the protocol by Mikki et al. [Brain Res. Protocols 2 (1997) 9-16], the use of an image analysis system is recommended in place of micrographs and photoprints for the counting and measuring of neuronal nuclei.

A simple stereologic method for analysis of cerebral cortical microvessels using image analysis

Previous methods for determining morphological features of vascular networks in cerebral cortex were subject to arbitrary variation and bias. Unbiased estimates of vessel number, volume, surface area and length can be obtained using stereology but these techniques tend to be tedious and time-consuming. Stereologic protocols generally require micrographs that have to be analyzed manually for intersections of vessels on grid points or lines. In this report, we provide a simpler and more precise method for measuring morphological features of cerebral cortical microvessels. Images of microvessels in 1 microm toluidine blue stained sections were captured using a popular image analysis software package. Luminal surfaces of endothelial cells were automatically traced using commonly available features; the two-dimensional data of vessels (diameter, area, perimeter and number of vessels) were automatically computed and transferred to a spreadsheet. Three-dimensional features were then determined using basic stereologic equations. The method eliminates the need for manual measurements and is particularly time- and cost-effective for quantitative studies where numerous images have to be evaluated.

A modified National Institutes of Health Stroke Scale for use in stroke clinical trials: preliminary reliability and validity

BACKGROUND AND PURPOSE

The National Institutes of Health Stroke Scale (NIHSS) is accepted widely for measuring acute stroke deficits in clinical trials, but it contains items that exhibit poor reliability or do not contribute meaningful information. To improve the scale for use in clinical research, we used formal clinimetric analyses to derive a modified version, the mNIHSS. We then sought to demonstrate the validity and reliability of the new mNIHSS.

METHODS

The mNIHSS was derived from our prior clinimetric studies of the NIHSS by deleting poorly reproducible or redundant items (level of consciousness, face weakness, ataxia, dysarthria) and collapsing the sensory item into 2 responses. Reliability of the mNIHSS was assessed with the certification data originally collected to assess the reliability of investigators in the National Institute of Neurological Disorders and Stroke (NINDS) rtPA (recombinant tissue plasminogen activator) Stroke

TRIAL

Validity of the mNIHSS was assessed with the outcome results of the NINDS rtPA Stroke Trial:

RESULTS

Reliability was improved with the mNIHSS: the number of scale items with poor kappa coefficients on either of the certification tapes decreased from 8 (20%) to 3 (14%) with the mNIHSS. With the use of factor analysis, the structure underlying the mNIHSS was found identical to the original scale. On serial use of the scale, goodness of fit coefficients were higher with the mNIHSS. With data from part I of the trial data, the proportion of patients who improved >/=4 points within 24 hours after treatment was statistically significantly increased by tPA (odds ratio, 1.3; 95% confidence limits, 1.0, 1.8; P=0.05). Likewise, the odds ratio for complete/nearly complete resolution of stroke symptoms 3 months after treatment was 1.7 (95% confidence limits, 1.2, 2.6) with the mNIHSS. Other outcomes showed the same agreement when the mNIHSS was compared with the original scale. The mNIHSS showed good responsiveness, ie, was useful in differentiating patients likely to hemorrhage or have a good outcome after stroke.

CONCLUSIONS

The mNIHSS appears to be identical clinimetrically to the original NIHSS when the same data are used for validation and reliability. Power appears to be greater with the mNIHSS with the use of 24-hour end points, suggesting the need for fewer patients in trials designed to detect treatment effects comparable to rtPA. The mNIHSS contains fewer items and might be simpler to use in clinical research trials. Prospective analysis of reliability and validity, with the use of an independently collected cohort, must be obtained before the mNIHSS is used in a research setting.

Apolipoprotein E phenotype and the efficacy of intravenous tissue plasminogen activator in acute ischemic stroke

We used stored plasma samples from 409 patients in the National Institute of Neurological Diseases and Stroke (NINDS) tissue plasminogen activator (t-PA) Stroke Trial to examine the relationship between an apolipoprotein (Apo) E2 or an Apo E4 phenotype and a favorable outcome 3 months after stroke, the risk of intracerebral hemorrhage, and the response to intravenous t-PA therapy. For the 27 patients with an Apo E2 phenotype who were treated with t-PA, the odds ratio (OR) of a favorable outcome at 3 months was 6.4 [95% confidence interval (CI) 2.7-15.3%] compared to the 161 patients without an Apo E2 phenotype who were treated with placebo. The 190 patients treated with t-PA who did not have an Apo E2 phenotype also had a greater, though less pronounced, likelihood of a favorable outcome (OR 2.0, 95% CI 1.2-3.2%) than patients without an Apo E2 phenotype treated with placebo. For the 31 patients with an Apo E2 phenotype treated with placebo, the OR of a favorable 3 month outcome was 0.8 (95% CI 0.4-1.7%) compared to the 161 patients without an Apo E2 phenotype treated with placebo. This interaction between treatment and Apo E2 status persisted after adjustment for baseline variables previously associated with 3 month outcome, for differences in the baseline variables in the two treatment groups and in the Apo E2-positive and -negative groups, and for a previously reported time-to-treatment x treatment interaction (p = 0.03). Apo E4 phenotype, present in 111 (27%) of the 409 patients, was not related to a favorable 3 month outcome, response to t-PA, 3 month mortality, or risk of intracerebral hemorrhage. We conclude that the efficacy of intravenous t-PA in patients with acute ischemic stroke may be enhanced in patients who have an Apo E2 phenotype, whereas the Apo E2 phenotype alone is not associated with a detectable benefit on stroke outcome at 3 months in patients not given t-PA. In contrast to prior studies of head injury and stroke, we could not detect a relationship between Apo E4 phenotype and clinical outcome.

Clinical deterioration following improvement in the NINDS rt-PA Stroke Trial

BACKGROUND AND PURPOSE

Little is known in regard to cerebral arterial reocclusion after successful thrombolysis. In the absence of arteriographic information, the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA Stroke Trial investigators prospectively identified clinical deterioration following improvement (DFI) as a possible surrogate marker of cerebral arterial reocclusion after rt-PA-induced recanalization. Also, we identified any significant clinical deterioration (CD) even if not preceded by improvement. This observational analysis was designed to determine the incidence of DFI and CD in each treatment group, to identify baseline or posttreatment variables predictive of DFI or CD, and to determine any relationship between DFI, CD, and clinical outcome.

METHODS

DFI was defined as any 2-point deterioration on the NIH Stroke Scale after an initial 2-point improvement after treatment. CD was defined as any 4-point worsening after treatment compared with baseline. All data were collected prospectively by investigators blinded to treatment allocation. A noncontrast brain CT was mandated when a 2-point deterioration occurred. All cases were validated by a central review committee.

RESULTS

DFI was identified in 81 of the 624 patients (13%); 44 were treated with rt-PA and 37 were treated with placebo (P:=0.48). DFI occurred more often in patients with a higher baseline NIH Stroke Scale score. CD within the first 24 hours occurred in 98 patients (16% of all patients); 43 were given rt-PA and 55 were given placebo (P:=0.19). Baseline variables associated with CD included a less frequent use of prestroke aspirin and a higher incidence of early CT changes of edema or mass effect or dense middle cerebral artery sign. Patients with CD had higher rates of increased serum glucose and fibrin degradation products, and they also had higher rates of symptomatic intracranial hemorrhage and death. Patients who experienced either DFI or CD were less likely to have a 3-month favorable outcome.

CONCLUSIONS

We found no association between DFI, CD, and rt-PA treatment, and no clinical evidence to suggest reocclusion. Deterioration was strongly associated with stroke severity and poor outcome and was less frequent in patients whose stroke occurred while they were on aspirin.

Finding the most powerful measures of the effectiveness of tissue plasminogen activator in the NINDS tPA stroke trial

BACKGROUND AND PURPOSE

We sought to identify the most powerful binary measures of the treatment effect of tissue plasminogen activator (tPA) in the National Institute of Neurological Disorders and Stroke (NINDS) rTPA Stroke Trial.

METHODS

Using the Classification and Regression Tree (CART) algorithm, we evaluated binary cut points and combination of binary cut points with the 4 clinical scales and head CT imaging measures in the NINDS tPA Stroke Trial at 4 times after treatment: 2 hours, 24 hours, 7 to 10 days, and 3 months. The first analysis focused on detecting evidence of "early activity" of tPA with the use of outcome measures derived from the 2-hour and 24-hour clinical and radiographic measures. The second analysis focused on longer-term outcome and "efficacy" and used outcome measures derived from 7- to 10-day and 3-month measures. After identifying the cut points with the ability to classify patients into the tPA and placebo groups using part I data from the trial, we then used data from part II of the trial to validate the results.

RESULTS

Of the 5 most powerful outcome measures for early activity of tPA, 4 involved the National Institutes of Health Stroke Scale (NIHSS) score at 24 hours or changes in the NIHSS score from baseline to 24 hours. The best overall single outcome measure was an NIHSS score </=2 at 24 hours, which provided an odds ratio of 5.4 (95% CI, 2.4 to 12.1) and a projected sample size of 58 per treatment group assuming an alpha of 0.05 (2-sided test) and a power of 80% using part I data. The top 2 and 3 of the top 5 outcome measures for detecting the longer-term efficacy of tPA also involved the NIHSS score. A Rankin score of 0 or 1 at 3 months was the third most powerful outcome measure. Outcome measures identified by CART from part I data were not as sensitive in detecting the effectiveness of tPA when applied to part II data.

CONCLUSIONS

Measures using the NIHSS and a Rankin score </=1 were the most sensitive discriminators of the effectiveness of tPA in the NINDS tPA Stroke Trial compared with the other clinical and radiological measures. The outcome measures identified in this exploratory analysis (eg, NIHSS score </=2 at 24 hours) would be best used as an outcome measure in future phase II trials of recanalization begun within the first 3 hours after stroke onset, with inclusion and exclusion criteria similar to those in the NINDS tPA Stroke Trial.

Synergistic combinatorial stroke therapy: A quantal bioassay of a GABA agonist and a glutamate antagonist

We sought to prolong the window for stroke treatment using synergistic combinatorial therapy. We used the intraluminal filament occlusion model in rats to cause focal cerebral ischemia and a quantal bioassay to measure efficacy. The GABA agonist muscimol and the glutamate antagonist MK-801 were used alone and in combination at various times after ischemia onset. At progressively longer treatment delay intervals (30, 60, 75, 120, 240, and 360 min), higher doses of the single drugs were required to achieve neuroprotection. In contrast, the combination 1.0 mg/kg muscimol plus 0.5 mg/kg MK-801 was effective at all delay intervals studied except the longest (P < 0.05 at each time). After 240 min from ischemia onset, the combination was more effective than either single agent (P < 0.05 for each drug dose), suggesting synergism. The neuroprotective effect could not be demonstrated using morphometry. The treatment effects were probably not due to hypothermia because brain temperatures recorded in awake, unregulated subjects remained normo- or slightly hyperthermic following all treatments. Awake subjects kept on a heating pad exhibited mild brain hyperthermia. The combination caused a drop and MK-801 caused a significant increase in mean arterial blood pressure (main effects F(5,172) = 29, P < 0.0001). The combination of a GABA agonist and glutamate antagonist appears to possess synergistic neuroprotective effects when treatment is delayed up to 240 min following the onset of cerebral ischemia. Temperature regulation causes hyperthermia in awake subjects. The quantal bioassay is one method suitable for studies of synergistic stroke therapy.

Does the National Institutes of Health Stroke Scale favor left hemisphere strokes? NINDS t-PA Stroke Study Group

BACKGROUND AND PURPOSE

The National Institutes of Health Stroke Scale (NIHSS) is a valid, reproducible scale that measures neurological deficit. Of 42 possible points, 7 points are directly related to measurement of language compared with only 2 points related to neglect.

METHODS

We examined the placebo arm of the NINDS t-PA stroke trial to test the hypothesis that the total volume of cerebral infarction in patients with right hemisphere strokes would be greater than the volume of cerebral infarction in patients with left hemisphere strokes who have similar NIHSS scores. The volume of stroke was determined by computerized image analysis of CT films and CT images stored on computer tape and optical disks. Cube-root transformation of lesion volume was performed for each CT. Transformed lesion volume was analyzed in a logistic regression model to predict volume of stroke by NIHSS score for each hemisphere. Spearman rank correlation was used to determine the relation between the NIHSS score and lesion volume.

RESULTS

The volume for right hemisphere stroke was statistically greater than the volume for left hemisphere strokes, adjusting for the baseline NIHSS (P<0. 001). For each 5-point category of the NIHSS score <20, the median volume of right hemisphere strokes was approximately double the median volume of left hemisphere strokes. For example, for patients with a left hemisphere stroke and a 24-hour NIHSS score of 16 to 20, the median volume of cerebral infarction was 48 mL (interquartile range 14 to 111 mL) as compared with 133 mL (interquartile range 81 to 208 mL) for patients with a right hemisphere stroke (P<0.001). The median volume of a right hemisphere stroke was roughly equal to the median volume of a left hemisphere stroke in the next highest 5-point category of the NIHSS. The Spearman rank correlation between the 24-hour NIHSS score and 3-month lesion volume was 0.72 for patients with left hemisphere stroke and 0.71 for patients with right hemisphere stroke.

CONCLUSIONS

For a given NIHSS score, the median volume of right hemisphere strokes is consistently larger than the median volume of left hemisphere strokes. The clinical implications of our finding need further exploration.

Thrombolysis for acute stroke

Thrombolysis for acute stroke is effective if administered according to the approved protocol. Since the initial report of success in 1995, a number of subsequent reports confirmed the safety and efficacy of this treatment. There is no particular subgroup of patients at increased likelihood of benefit or hemorrhage that can be identified at baseline. Unlike many expensive therapies, thrombolysis for acute stroke saves the health care system considerable long-term costs. The search for even safer and more effective thrombolytics continues.

Criteria for selection of older patients for thrombolytic therapy

Thrombolysis is the first effective treatment for stroke. Considerable preclinical and early clinical studies set the stage for the final, definitive demonstration of rtPA efficacy. Since the publication of the original trial, there have been a number of subsequent analyses of subgroups. In particular, the authors discuss the use of thrombolytic therapy in elderly people. There is limited evidence that rtPA is effective at all ages. Criteria for selecting patients and management guidelines are presented.

Agreement and variability in the interpretation of early CT changes in stroke patients qualifying for intravenous rtPA therapy

BACKGROUND AND PURPOSE

Ischemic changes identified on CT scans performed in the first few hours after stroke onset, which are thought to possibly represent early cytotoxic edema and development of irreversible injury, may have important implications for subsequent treatment. However, insecurity and conflicting data exist over the ability of clinicians to correctly recognize and interpret these changes. We performed a detailed review of selected baseline CT scans from the NINDS rt-PA Stroke Trial to test agreement among experienced stroke specialists and other physicians on the presence of early CT ischemic changes.

METHODS

Seventy baseline CT scans from the NINDS Stroke Trial were read and classified for the presence or absence of various early findings of ischemia by 16 individuals, including NINDS trial investigators, other neurologists, other emergency medicine physicians, and radiology or stroke fellows. CT scans included normal scans and scans from patients who later developed symptomatic intracranial hemorrhage, as well as scans on which the NINDS rt-PA Stroke Trial neuroradiologist identified clear-cut early CT changes. For each CT finding, kappa-statistics were used to assess the proportion of agreement beyond chance.

RESULTS

kappa-Values (95% confidence interval [CI]) ranged from 0.20 (-0.20, 0.61) (fair agreement) to 0.41 (0.37, 0.45) (moderate agreement) among the 16 viewers, and the kappa-value was only 0.39 (0.29, 0.49) (fair) in answer to the question "do early CT changes involve more than one third of the MCA [middle cerebral artery] territory?" There was substantial variability within each specialty group and between groups. kappa-Values were only fair to moderate even among physicians experienced in selecting and treating acute stroke patients with rtPA. Observed agreement ranged from 68% to 85%. Physicians agreed on the finding of early CT changes involving >33% of the MCA territory 77% of the time, although the kappa-value of 0.39 suggested only moderate agreement beyond chance.

CONCLUSIONS

There is considerable lack of agreement, even among experienced clinicians, in recognizing and quantifying early CT changes. Improved methods of recognizing and quantifying early ischemic brain damage are needed.

The clomethiazole acute stroke study in ischemic, hemorrhagic, and t-PA treated stroke: Design of a phase III trial in the united states and canada

Clomethiazole is a drug with sedative properties effective in laboratory studies of brain ischemia. A large European multicenter trial of clomethiazole in acute stroke patients showed no benefit overall, but subgroup analysis indicated that patients with large infarctions may have benefited from treatment. To confirm this preliminary finding, we have designed CLASS-IHT, the Clomethiazole for Acute Stroke Study in Ischemic, Hemorrhagic and TPA Treated Patients, to be conducted in North America. Patients who suffer large cerebral infarctions and present within 12 hours of symptom onset are eligible. Patients will be randomized to receive clomethiazole 68 mg/kg over 24 hours or vehicle, using a dosing scheme based on the pharmacokinetics measured in the first trial. Outcome assessments include stroke scales, the Barthel Index, and lesion volume. An additional study of health economic outcomes is planned. The primary endpoint for CLASS-I will be the Barthel Index 90 days after stroke. A total of 1,200 patients will be randomized to CLASS-I, and in safety-only trials, 200 patients with cerebral hemorrhage will be randomized into CLASS-H and another 100 to 200 patients will be randomized into CLASS-T. The details of the protocols for all three studies are presented.

Acute hypertension promotes hemorrhagic transformation in a rabbit embolic stroke model: effect of labetalol

We examined the relationship between acute hypertension following cerebral embolization and subsequent hemorrhagic transformation (HT) in a rabbit embolic stroke model. We have shown previously that the likelihood and severity of hemorrhage were significantly correlated with the magnitude of an acute hypertensive response to embolization. It was not clear, however, whether hypertension actually caused hemorrhage or was merely a marker of more severe stroke. In the current studies, we attempted to clarify the relationship between acute hypertension and HT by either pharmacologically inducing or attenuating the brief hypertensive response to embolization in rabbits. Under halothane anesthesia, two catheters were implanted in the right carotid arteries of male New Zealand white rabbits, one oriented toward the heart and one toward the brain. The animals were allowed to awaken and were embolized using blood clot emboli injected into the middle cerebral artery. Blood pressure was monitored via the second carotid catheter. In the first experiment, hypertension was induced with angiotensin II, administered at the time of embolization or 1 h later. In the second experiment, we attempted to attenuate the hypertensive response using intravenous labetalol. The animals were sacrificed 18 h after embolization and the brains evaluated for hemorrhage. In the first experiment, administration of angiotensin II immediately after embolization did not increase the hypertensive response to embolization further than that spontaneously occurring, and no angiotensin II-related HT was observed. In contrast, an additional angiotensin-II-induced hypertensive episode 1 h after embolization significantly increased the number of 5-mm serial brain sections displaying HT, from 3.0 +/- .3 (mean +/- SE) in Controls to 5.4 +/- .8 in treated animals. In the second experiment, administration of labetalol (15 mg/kg) significantly reduced the number of brain sections with visible HT, from 3.2 +/- .5 in controls to 1.6 +/- .4 in treated animals. Acute hypertension during the first hour after cerebral embolization promotes HT in this rabbit embolic stroke model. Labetalol prevents blood pressure elevation and reduces the extent of HT in the same model.

Assessment scales for the evaluation of stroke patients

The approval of tissue plasminogen activator to treat acute ischemic stroke and the continuing need to evaluate new neuroprotective drugs and thrombolytic agents in clinical trials have focused interest on the quantitative evaluation of stroke patients. Emphasizing outcomes management in clinical practice has also heightened the importance of quantitative evaluation using assessment scales. Investigators who evaluate, revise, and use assessment scales for the measurement of stroke impairment, disabilites, and handicaps face many challenges. These problems include the heterogeneity of stroke and the need to determine appropriate outcome measures, to use neurological deficit scales that can accurately predict disability, to ensure adequate follow-up, and to use scales that can be used outside of clinical trials by all health care professionals. Such scales should be easily and quickly administered, responsive, valid, and reliable. The most important categories of stroke scales are neurological deficit scales (e.g., Canadian Neurological Scale, European Stroke Scale, and National Institutes of Health [NIH] Stroke Scale), functional outcome scales (e.g., Barthel Index), and global outcome scales (e.g., Modified Rankin Scale). Although stroke-specific, health-related quality-of-life (HRQL) scales have yet to be developed and validated, general HRQL scales such as the Nottingham Health Profile, the Medical Outcomes Study Short Form-36, the Sickness Impact Profile, and the Health Utilities Index may be used to assess stroke patients. Lacking the ideal single stroke outcome scale, we continue to recomend a combination of scales: the NIH Stroke Scale (or similar deficit scale), the Barthel Index, and the Rankin Scale.

Medical and neurological complications of ischemic stroke: experience from the RANTTAS trial. RANTTAS Investigators

BACKGROUND AND PURPOSE

Medical and neurological complications after acute ischemic stroke may adversely impact outcome and in some cases may be preventable. Limited data exist regarding the frequency of such complications occurring in the first days after the ictus and the relationship of these complications to outcome. Our objective was to identify the types, severity, and frequency of medical and neurological complications following acute ischemic stroke and to determine their role in mortality and functional outcome.

METHODS

Rates of serious (life-threatening) and nonserious medical and neurological complications and mortality were derived from the placebo limb of the Randomized Trial of Tirilazad Mesylate in Acute Stroke (RANTTAS) database (n=279). Complications were correlated with clinical outcome using logistic regression techniques.

RESULTS

Of all patients, 95% had at least one complication. The most common serious medical complication was pneumonia (5%), and the most common serious neurological complication was new cerebral infarction or extension of the admission infarction (5%). The 3-month mortality was 14%; 51% of these deaths were attributed primarily to medical complications. Outcome was significantly worse in patients with serious medical complications, after adjustment for baseline imbalances, as measured by the Barthel Index (odds ratio [OR], 6.1; 95% confidence interval [CI], 2.5 to 15.1) and by the Glasgow Outcome Scale (OR, 11.6; 95% CI, 4.3 to 30.9). After death was discounted, serious medical complications were associated with severe disability at 3 months as determined by the Glasgow Outcome Scale (OR, 4.4; 95% CI, 1.3 to 14.8).

CONCLUSIONS

Medical complications that follow ischemic stroke not only influence mortality but may influence functional outcome.

Total quality improvement method for reduction of delays between emergency department admission and treatment of acute ischemic stroke. The National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group

OBJECTIVE

To develop an approach for reducing time between emergency department (ED) admission and treatment in patients with acute ischemic stroke to meet the challenge of providing tissue plasminogen activator treatment within 180 minutes.

DESIGN

An observational study.

SETTING

Forty trial-affiliated hospitals, including 30 community hospitals.

PARTICIPANTS

A total of 17,324 consecutive patients admitted to trial-affiliated hospital EDs within 24 hours of possible stroke, from January 1991 through October 1994.

INTERVENTION

Appraisal of the process of triage, evaluation, diagnosis, and treatment by means of total quality improvement techniques in each hospital. Staff participating in the process identified sources of variation and modifications by flow charting the process.

MAIN OUTCOME MEASURE

Time between ED admission and treatment with study medication.

RESULTS

Total quality improvement methods identified hospital-specific process improvements. Many improvements were administrative, requiring no additional resources. More than 50% of screened patients arrived too late to be treated. Only 1268 patients were admitted between 0 and 125 minutes from stroke onset with no other trial exclusion criteria; 48% were treated. Of 243 patients admitted between 126 and 170 minutes from stroke onset with no exclusion criteria, 4% were treated. Mean time from ED admission to treatment was similar in teaching and community hospitals.

CONCLUSIONS

Total quality improvement methods identified ED-specific sources of process variability and reduced time between ED admission and treatment. Therefore, these methods should be considered in developing and monitoring emergent stroke treatment protocols.

High dose baclofen is neuroprotective but also causes intracerebral hemorrhage: a quantal bioassay study using the intraluminal suture occlusion method

Agonists of the GABA-A receptor are neuroprotective after experimental stroke, but studies of GABA-B agonists have contradicted each other. To further investigate whether GABA-B agonists may be neuroprotective, we devised a quantal bioassay using the intraluminal occlusion method of inducing reversible cerebral ischemia. Subjects underwent middle cerebral artery occlusion for varying amounts of time, ranging from 5 to 90 min. Behavioral outcome was measured 48 h later with a quantal observational scale: score of abnormal given for any one of asymmetric forepaw flexion on tail lift, asymmetric grip, circling, reduced exploration, seizures, or death. To the grouped response data the logistic equation was used to find the ED50, the duration of occlusion that caused one-half of the subjects to be abnormal. To find the potency ratio for each drug, we divided the ED50 for treatment by that for vehicle. We administered baclofen, a GABA-B agonist, intraperitoneally 5 min after the onset ofischemia. Baclofen (20 mg/kg) was neuroprotective (potency ratio of 3.0, P < 0.05), but a lower dose (10 mg/kg) was not. However, both doses of baclofen caused significantly more intracerebral hemorrhages than control. In awake animals, both baclofen doses caused significant increases in mean arterial pressure, but no changes in other cardiorespiratory variables. The glutamate antagonist MK-801, the GABA-A agonist muscimol, and hypothermia were all protective using the bioassay (potency ratios ranging from 1.5 to 3.0). We conclude that although baclofen (20 mg/kg) may be neuroprotective, its utility is complicated by postischemic hypertension and cerebral hemorrhages.

Effect of ischemic cerebral volume changes on behavior

Ischemia causes long-term effects on brain volume and neurologic function but the relationship between the two is poorly characterized. We studied the relationships between brain volume and three measures of rodent behavior after cerebral ischemia was induced by injecting several thousand microspheres into the internal carotid arteries of rats. Forty eight hours later, each subject was rated using a global neurologic rating scale. Several weeks later, the subjects were tested for open field activity and visual spatial learning. Post-mortem we measured the volume of the cerebral hemispheres and estimated the volume densities of cortex, white matter, hippocampus, basal ganglia, thalamus, ventricle, and visible infarction. Ischemia caused significant impairment, as measured by the global rating scale; the probability of an abnormal rating was correlated with the number of microspheres trapped in the brains. Visual spatial learning was significantly impaired by ischemia, but this deficit was independent of the count of microspheres, whether the subject was abnormal at 48 h, and whether the left or right hemisphere was embolized. Cerebral hemisphere volume was reduced from 430 mm3 to 376 mm3 (P < 0.05). The cortex was reduced from 22 to 19% of cerebrum (P < 0.05) and the white matter compartment was reduced to similar degree. The lesion volume was 6% of cerebrum, comparable to that seen with other ischemia methods. The global outcome rating was significantly related to total cerebral volume, but not to volume changes in any single compartment. On the other hand, visual spatial learning was significantly influenced by volume changes in the cortex and white matter, but not by the topography of the visible infarctions. Open field activity was not altered by infarction. Our data suggests that the total volume of brain tissue lost to infarction may partially determine global neurological rating independently of the topography of the volume loss. Integrative functions such as learning may depend more on the integrity of specific compartments and less on the total volume of intact brain. The volume of visible cystic infarction was not related to long term behavioral outcome. These results should be confirmed using another method of inducing ischemia.

Medical therapy for intracerebral hematoma with the gamma-aminobutyric acid-A agonist muscimol

BACKGROUND AND PURPOSE

No therapy has been rigorously proven effective for intracerebral hematoma, although surgery is frequently used for some types of lobar hemorrhages. Since intracerebral mass causes significant ischemia in surrounding brain, we reasoned that anti-ischemia therapy might improve outcome after experimental hematoma.

METHODS

We stereotaxically injected varying doses of bacterial collagenase into the caudate nucleus of rats. Four hours later we administered intravenously 2 mg/kg muscimol, a potent agonist of the gamma-aminobutyric acid-A receptor (n = 20); 1 mg/kg MK-801, an antagonist of the N-methyl-D-aspartate receptor (n = 17); or saline (n = 28). Forty-eight hours after collagenase injection we rated each animal using a standard rodent neurological examination. The ratings were compared with the amounts of injected collagenase by the quantal bioassay procedure. Brains were then prepared for histomorphometry and brain volumes estimated.

RESULTS

We found that the ED50 for collagenase (amount of enzyme that renders 50% of the subjects abnormal) was 0.77 +/- 0.09 U in saline-treated subjects. Treatment with muscimol significantly increased the ED50 to 1.2 +/- 0.21 U, for a potency ratio of 1.55 +/- 0.34 (t = 1.7, P < .05). MK-801 did not affect outcome. Volume of hematoma was significantly correlated with amount of injected collagenase (n = 33, r = .64, P < .001). Volumes of basal ganglia and white matter were significantly reduced by hemorrhage, and muscimol partially ameliorated this.

CONCLUSIONS

We conclude that muscimol significantly improves neurological outcome after intracerebral hematoma.

Visualization of the cerebral circulation using three-dimensional transcranial power Doppler ultrasound imaging

The purpose of this study was to evaluate the anatomy of the cerebral circulation, particularly the circle of Willis, using three-dimensional ultrasound (3DUS) imaging. Image data were obtained through the right transtemporal window from 8 young, healthy volunteers by acquiring gray-scale and color Doppler spectral (CDI) and energy (CDE) images using two-dimensional ultrasound equipment with a 2-MHz probe. Images and transducer position coordinates were fed into a graphics workstation, reprojected, analyzed to extract the blood flow signal, volume rendered, and displayed interactively. The architecture of the cerebral circulation was evaluated from multiple orientations using stereo viewing glasses and rotation to enhance the understanding of vessel position. The primary vessels of the cerebral circulation including the circle of Willis and bilateral views of the branching arteries (middle, anterior, and posterior cerebral arteries and internal carotid artery) could be imaged readily with 3DUS through one transtemporal window. Acquisition time was typically less than 30 seconds. Volume-rendering methods greatly assisted in showing the overall spatial relationships and continuity of cranial vessels. Secondary branches of the cerebral arteries were seen in 2 patients. Color data from two-dimensional ultrasound imaging that otherwise might be identified as artifact was found to represent continuous small vessels on three-dimensional viewing. 3DUS facilitates imaging of cranial vascular anatomy by clarifying overall spatial relationships and enhancing comprehension, compared to two-dimensional ultrasound methods. The method is rapid and the circle of Willis can be visualized from one side of the head.

Spontaneous early improvement following ischemic stroke

BACKGROUND AND PURPOSE

Recognizing that early spontaneous neurological improvement not uncommonly follows acute ischemic stroke, we conducted this study to determine the incidence of such improvement and its potential relation to stroke etiology.

METHODS

We prospectively evaluated 68 patients who presented within 12 hours after ischemic stroke, exhibited moderate or severe new functional neurological deficit acutely, and received either no stroke-specific therapy or only antiplatelet therapy over the ensuring week. We reexamined all patients 1 week after stroke onset.

RESULTS

Sixteen (24%) of the 68 patients improved to the point of having no or mild functional neurological deficit at 1 week. Patients with lacunar stroke were more likely to enjoy early spontaneous improvement (8/22 = 36% versus 8/46 = 17%), but this difference did not reach statistical significance (P = .15).

CONCLUSIONS

Early spontaneous improvement after ischemic stroke may occur in a substantial proportion of patients and more commonly after lacunar stroke. Even so, the majority of patients with acutely disabling stroke will remain significantly impaired 1 week after stroke onset.

Impact of race and ethnicity on ischemic stroke. The University of California at San Diego Stroke Data Bank

BACKGROUND AND PURPOSE

As the US minority population continues to grow, increasing numbers of nonwhite citizens are at risk for stroke. A better understanding of how ischemic stroke differs in the minority populations may lead to more effective clinical management.

METHODS

We prospectively evaluated 542 consecutive patients (416 whites, 71 Mexican Americans, 55 blacks) presenting to the University of California at San Diego Medical Center or the San Diego Veterans Affairs Hospital with presumed acute ischemic stroke or transient ischemic attack.

RESULTS

Whites had a higher proportion of transient ischemic attacks (32% versus 18% and 17% for blacks and Mexican Americans, respectively) and had the lowest prevalence of diabetes mellitus (17% versus 29% and 40% for blacks and Mexican Americans, respectively). Mexican Americans had higher initial serum glucose levels (178 versus 133 and 131 mg/dL for whites and blacks, respectively). Blacks were youngest (average age, 56 years). There were no differences among the groups in the prevalence of prior stroke, hypertension, myocardial infarction, or smoking; initial systolic blood pressure, serum cholesterol levels, and functional deficit also were similar. Although it did not reach statistical significance, there was a trend toward relatively late presentation in the black stroke subpopulation: only 53% of blacks (compared with 73% of both Mexican Americans and whites) reached medical attention within 24 hours of stroke onset. All groups had similar diagnostic evaluations and functional outcome at 1 week. With the exception of a higher frequency of stroke of unknown cause in Hispanics, the distributions of stroke etiologies did not differ significantly among the groups.

CONCLUSIONS

These data suggest that there are significant clinical differences in populations with ischemic stroke and transient ischemic attack that are related to race and ethnic origin, but in our population these differences did not include the extent of diagnostic evaluation undertaken or stroke severity.

Gait parameters following stroke: a practical assessment

Mechanical methods of quantifying gait are more sensitive to change than is direct clinical inspection. To assess gait parameters and patterns of patients with stroke, and the temporal changes of these parameters, a foot-switch gait analyzer was used to test 49 ambulatory patients with stroke and 24 controls. Patients walked significantly slower than controls, with decreased cadence, increased gait cycle, and increased time in double limb support. Patients' hemiplegic limbs spent more time in swing and stance when compared to controls; their unaffected limbs spent significantly more time in stance and single limb support compared to controls. Patients' hemiplegic side, when compared with the unaffected side, spent less time in stance and more time in swing. A flatfoot pattern was typically noted on the affected side. General gait parameters improved over time, with the largest changes occurring in the first 12 months. However, the percentage of time spent in double and single limb support, stance and swing, parameters which describe the asymmetrical pattern of gait, did not change over time. Abnormal gait was due to difficulty in moving the body over an unstable limb. Gait analysis can be of importance in documenting abnormalities and determining the effects of therapeutic modalities.

A rapid, reliable, and valid method for measuring infarct and brain compartment volumes from computed tomographic scans

BACKGROUND AND PURPOSE

Clinical stroke trials require objective and reproducible end point variables. Morphometry of cerebral structures, including infarct volume, provides numerical measures that represent the amount of tissue damaged and potentially salvaged by therapy. However, morphometry may be time-consuming and labor-intensive, and it requires standardization across multiple centers, which may be difficult to achieve in large multicenter trials. We developed a brain morphometry method that is unbiased, rapid, reliable, and based on well-accepted stereological techniques. We now extend this method to analysis of routine computed tomographic (CT) scans such as might be obtained during a clinical stroke trial.

METHODS

We studied CT scans from 18 stroke patients and 14 asymptomatic control patients obtained over 5 years at the San Diego Veterans Administration Medical Center. Three observers independently measured the volume of the cranial vault, cerebrum, cortex, white matter, deep gray structures, ventricle, sulcal cerebrospinal fluid space, visible infarction, and cerebellum/brain stem.

RESULTS

The two patient groups were well matched demographically. The intracranial volume of 1400 +/- 40 mL in control subjects was not different from the 1311 +/- 41 mL in patients. Cerebral volume was 1250 +/- 36 mL compared with 1070 +/- 36 mL (control subjects versus patients, P < .001), and infarction volume was 55 +/- 16 mL in patients. For all structures, intraclass correlation coefficients among the observers ranged from 0.87 to 0.03; the best agreement was found for lesion, ventricle, and intracranial volume. White matter and cortex volume predicted the National Institutes of Health Stroke Scale score but not the late outcome scores on the Barthel Index or Rankin Scale. Each scan required 70 to 90 minutes for analysis.

CONCLUSIONS

We developed a stereological method for cerebral morphometry from CT scans that is reliable, rapid, and simple. The measurements are unbiased, can be made on slices of any known thickness, and are independent of machine variables. Our results are remarkably similar to values obtained with more labor-intensive methods. This method should be of use in large-scale, multicenter trials of stroke therapy.

Combination therapy protects ischemic brain in rats. A glutamate antagonist plus a gamma-aminobutyric acid agonist

BACKGROUND AND PURPOSE

The excitotoxic effects of glutamate can be blocked almost completely with gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter, in cell culture, tissue slices, and in some animal models. After stroke in rats, we showed previously that an agonist of GABA, muscimol, was as neuroprotective as MK-801, an antagonist of glutamate. To obtain further neuroprotection and to avoid the side effects associated with high doses of MK-801, we wanted to assess the efficacy of the two agents in combination.

METHODS

Treatment was administered 5 minutes after embolic cerebral ischemia in Sprague-Dawley rats. The subjects were rated using a neurological evaluation 48 hours later. Visual-spatial learning was measured 8 to 10 weeks after stroke, after which we measured the volume of each cerebral hemisphere and several large cerebral compartments. Treatment groups included saline (n = 27), MK-801 1.0 mg/kg (n = 23), muscimol 1.0 mg/kg (n = 17), and both agents together using a dose of 0.5 mg/kg each (n = 25).

RESULTS

A probit analysis of the neurological ratings revealed a protective effect of muscimol used alone (MK-801 potency ratio, 2.0; P = NS; muscimol potency ratio, 4.0; P < .05) and a protective effect of the combination (potency ratio, 5.0; P < .05). Focal ischemia caused a moderate to severe delay in the acquisition of visual-spatial information, which was completely eliminated by the combination treatment but only partially ameliorated with MK-801 or muscimol alone. Ischemia reduced the cerebral hemisphere volume from 0.42 mm3 to 0.34 mm3 (P < .0001), the volume density of cortex from 22% to 17% of total cerebral volume (P < .01), and that of hippocampus from 4.3% to 3.0% (P < .05). Only the combination was neuroprotective, as measured by the ratio of the lesioned to the contralateral hemisphere volume (P = .013). The combination treatment and MK-801 protected the hemisphere volume, the cortex, and the hippocampus and reduced the size of visible infarction.

CONCLUSIONS

Combination therapy, using a glutamate antagonist and a GABA-A agonist, appeared to protect the brain and ameliorate a defect in learning behavior after stroke. The combination may have been more effective than either agent used alone, although further study of higher doses is needed.

An analysis of ischemic stroke in an urban southern California population. The University of California, San Diego, Stroke Data Bank

BACKGROUND

Stroke databanks may provide important information regarding regional and temporal variations in the causes of stroke.

METHODS

Five hundred consecutive patients presenting to the University of California, San Diego, stroke services with acute ischemic stroke were evaluated prospectively. A specific cause of stroke was assigned in each case according to predetermined diagnostic criteria.

RESULTS

Relative incidences of ischemic stroke causes were as follows: lacunar, 27%; unknown cause, 23%; cardioembolic, 22%; large-vessel atherothrombotic/embolic, 18%; and miscellaneous, 10%.

CONCLUSIONS

These relatively high rates of lacunar stroke and stroke of unknown cause are similar to those from other recent surveys and may reflect an important shift in the pathophysiologic mechanisms that underlie ischemic stroke.

Protective effect of synaptic inhibition during cerebral ischemia in rats and rabbits

BACKGROUND

Excitatory neurotransmitters appear to cause cell death during ischemia by inducing depolarization, influx of ions, and metabolic failure in the postsynaptic neuron. If this hypothesis is correct, then postsynaptic membrane hyperpolarization and inhibition of metabolism may be protective. Antagonists of the excitotoxic amino acid glutamate protect neurons in culture and in animal models of stroke but appear to cause unacceptable side effects in humans. We propose an alternative strategy of protection using agonists of the inhibitory neurotransmitter gamma-aminobutyric acid.

METHODS

We caused multifocal cerebral ischemia in rats and rabbits by injecting microspheres into the carotid circulation. We administered saline, muscimol, or MK-801 within 5 minutes of stroke onset. We used a bioassay to measure outcome. In rats, we also used learning to assess cortical function, and we performed detailed quantitative brain morphometry 3 months after infarction.

RESULTS

Using the bioassay, we found that muscimol exerted a protective effect in rats (p less than 0.01). There was a dose-response effect seen in muscimol-treated rabbits. Rats treated with muscimol or MK-801 exhibited significantly better visual-spatial learning compared with saline-treated subjects (p less than 0.001). Hemisphere volume after ischemia was comparable in all groups.

CONCLUSIONS

Agonists of gamma-aminobutyric acid and antagonists of glutamate appear to protect brain during ischemia. Since agonists of gamma-aminobutyric acid are known to have fewer side effects in humans, they may prove more useful in the clinical setting as neuroprotective agents.

Quantitative effects of cerebral infarction on spatial learning in rats

Outcome following stroke is difficult to measure because the behavioral response to infarction is variable. We hypothesized that cognitive function, such as spatial learning, may be a reproducible and sensitive outcome variable. We developed an animal model of multifocal cerebral ischemia in order to study the effects of infarction on learning. To cause ischemia, several hundred microspheres were injected into the internal carotid arteries of rats. After ischemia, behavior was measured using a global rating and a Morris water maze. Postmortem serial brain sections were stained and the size of the infarctions was measured. We found that intracerebral microspheres caused cortical infarction and an impairment of spatial learning. This impairment was not due to occlusion of the internal carotid artery and was not found in animals who received a sham injection of saline. The degree of learning impairment was not correlated with the volume density of the infarctions or with the volume density of the remaining cerebral hemisphere. The learning impairment clearly differentiated normal from lesioned animals, and the impairment was probably due to a delay in acquisition of spatial information rather than a defect in retention or retrieval. Measurement of learning deficit after cerebral ischemia is an efficient and sensitive method for evaluating new stroke treatments and possibly for exploring structure function relationships.