Acute ischemic stroke: overview of recent therapeutic developments

Stroke, a disorder encompassing all cerebrovascular accidents, is a public health problem of immense proportions across the globe. Therapeutic efforts are directed at three aspects: prevention, acute treatment, and rehabilitation. Preventative measures, which in many instances mirror those for cardiovascular disease, can achieve the greatest public health impact. Measures that enhance the recovery of neurologic function and reduce neurologic disability after stroke can also affect a large population of handicapped stroke survivors. In the past 10 years, the greatest changes have occurred in the field of acute stroke treatment. Ultra-early-stage therapies with the potential to dramatically reverse severe neurologic deficits, or halt their progression, have caused a restructuring of the emergency care of neurologic patients. The parallels with the evolution of emergency treatment of acute coronary syndromes after 1970 are striking. This review focuses on aspects of stroke therapy that are either just entering, or soon to enter, current practice.

The Case for Modality-Specific Outcome Measures in Clinical Trials of Stroke Recovery-Promoting Agents

Clinical trials for acute stroke treatments have often used composite clinical rating scales as primary outcome measures of treatment efficacy. Recent preclinical and clinical studies highlight the opportunity to administer treatments in the subacute and chronic phase of stroke to promote neurological recovery. Because different neurological deficits recover to different extents at different rates after stroke, putative stroke recovery-promoting treatments may exert differential effects on various functional aspects of stroke recovery. For this reason, we propose that the use of modality-specific outcome measures may be best suited as primary end points in clinical trials of stroke recovery-promoting agents. The use of such end points may result in a more selective labeling of stroke recovery treatments.

Practice Standards for Transcranial Doppler Ultrasound: Part I-Test Performance

Indications for the clinical use of transcranial Doppler (TCD) continue to expand while scanning protocols and quality of reporting vary between institutions. Based on literature analysis and extensive personal experience, an international expert panel started the development of guidelines for TCD performance, interpretation, and competence. The first part describes complete diagnostic spectral TCD examination for patients with cerebrovascular diseases. Cranial temporal bone windows are used for the detection of the middle cerebral arteries (MCA), anterior cerebral arteries (ACA), posterior cerebral arteries (PCA), C1 segment of the internal carotid arteries (ICA), and collateralization of flow via the anterior (AComA) and posterior (PComA) communicating arteries; orbital windows-for the ophthalmic artery (OA) and ICA siphon; the foraminal window-for the terminal vertebral (VA) and basilar (BA) arteries. Although there is a significant individual variability of the circle of Willis with and without disease, the complete diagnostic TCD examination should include bilateral assessment of the M2 (arbitrarily located at 30-40 mm depth), M1 (40-65 mm) MCA [with M1 MCA mid-point at 50 mm (range 45-55 mm), average length 16 mm (range 5-24 mm), A1 ACA (60-75 mm), C1 ICA (60-70 mm), P1-P2 PCA (average depth 63 mm (range 55-75 mm), AComA (70-80 mm), PComA (58-65 mm), OA (40-50 mm), ICA siphons (55-65 mm), terminal VA (40-75 mm), proximal (75-80), mid (80-90 mm), and distal (90-110 mm) BA]. The distal ICA on the neck (40-60 mm) can be located via submandibular windows to calculate the VMCA/VICA index, or the Lindegaard ratio for vasospasm grading after subarachnoid hemorrhage. Performance goals of diagnostic TCD are to detect and optimize arterial segment-specific spectral waveforms, determine flow direction, measure cerebral blood flow velocities and flow pulsatility in the above-mentioned arteries. These practice standards will assist laboratory accreditation processes by providing a standard scanning protocol with transducer positioning and orientation, depth selection and vessel identification for ultrasound devices equipped with spectral Doppler and power motion Doppler.

The real estate factor: quantifying the impact of infarct location on stroke severity

BACKGROUND AND PURPOSE

The severity of the neurological deficit after ischemic stroke is moderately correlated with infarct volume. In the current study, we sought to quantify the impact of location on neurological deficit severity and to delineate this impact from that of volume.

METHODS

We developed atlases consisting of location-weighted values indicating the relative importance in terms of neurological deficit severity for every voxel of the brain. These atlases were applied to 80 first-ever ischemic stroke patients to produce estimates of clinical deficit severity. Each patient had an MRI and National Institutes of Health Stroke Scale (NIHSS) examination just before or soon after hospital discharge. The correlation between the location-based deficit predictions and measured neurological deficit (NIHSS) scores were compared with the correlation obtained using volume alone to predict the neurological deficit.

RESULTS

Volume-based estimates of neurological deficit severity were only moderately correlated with measured NIHSS scores (r=0.62). The combination of volume and location resulted in a significantly better correlation with clinical deficit severity (r=0.79, P=0.032).

CONCLUSIONS

The atlas methodology is a feasible way of integrating infarct size and location to predict stroke severity. It can estimate stroke severity better than volume alone.

Unusual visual symptoms in a patient with bilateral vertebral artery dissection: A case report

We present a previously unreported set of symptoms in a patient found to have bilateral vertebral dissections. Although visual symptoms are common in vertebral dissection, their pattern does not typically mimic those that commonly precede or accompany migraine headache. When they do occur, they usually take the form of diplopia or blurred vision. The patient we describe had visual symptoms that varied over three episodes of headache and included transient visual field loss and scintillations ("lightning bolts"), both common in migraine. However, our patient's new visual symptoms represented a change in pattern from those that had accompanied her previous migraines. This detailed history-taking prompted an evaluation for an etiology other than migraine and prevented a further delay in diagnosis and treatment.

Association between tPA therapy and raised early matrix metalloproteinase-9 in acute stroke

BACKGROUND

Matrix metalloproteinase-9 (MMP9) is expressed in acute ischemic stroke and up-regulated by tissue plasminogen activator (tPA) in animal models. The authors investigated plasma MMP9 and its endogenous inhibitor, tissue inhibitor of metalloproteinase (TIMP1), in tPA-treated and -untreated stroke patients.

METHODS

Nonstroke control subjects and consecutive ischemic stroke patients presenting within 8 hours of onset were enrolled. Blood was sampled within 8 hours and at 24 hours, 2 to 5 days and 4 to 6 weeks. MMP9 and TIMP1 were analyzed by ELISA and gel zymography.

RESULTS

Fifty-two cases (26 tPA treated, 26 tPA untreated) and 27 nonstroke control subjects were enrolled. Hyperacute MMP9 was elevated in tPA-treated vs tPA-untreated patients (medians 43 vs 28 ng/mL; p = 0.01). tPA therapy independently predicted hyperacute MMP9 after adjustment for stroke severity, volume, and hemorrhagic transformation (p = 0.01). There was a trend toward lower hyperacute TIMP1 levels in tPA-treated vs tPA-untreated patients (p = 0.06). Hyperacute MMP9 was correlated to poor 3-month modified Rankin Scale outcome (r = 0.58, p = 0.0005).

CONCLUSION

Tissue plasminogen activator independently predicted plasma matrix metalloproteinase-9 (MMP9) in the first 8 hours after human ischemic stroke. As MMP9 may be an important mediator of hemorrhagic transformation, alternative thrombolytic agents or therapeutic MMP9 inhibition may increase the safety profile of acute stroke thrombolysis.

Neuroanatomic correlates of stroke-related myocardial injury

BACKGROUND

Myocardial injury can occur after ischemic stroke in the absence of primary cardiac causes. The neuroanatomic basis of stroke-related myocardial injury is not well understood.

OBJECTIVE

To identify regions of brain infarction associated with myocardial injury using a method free of the bias of an a priori hypothesis as to any specific location.

METHODS

Of 738 consecutive patients with acute ischemic stroke, the authors identified 50 patients in whom serum cardiac troponin T (cTnT) elevation occurred in the absence of any apparent cause within 3 days of symptom onset. Fifty randomly selected, age- and sex-matched patients with ischemic stroke without cTnT elevation served as controls. Diffusion-weighted images with outlines of infarction were co-registered to a template, averaged, and then subtracted to find voxels that differed between the two groups. Voxel-wise p values were determined using a nonparametric permutation test to identify specific regions of infarction that were associated with cTnT elevation.

RESULTS

The study groups were well balanced with respect to stroke risk factors, history of coronary artery disease, infarction volume, and frequency of right and left middle cerebral artery territory involvement. Brain regions that were a priori associated with cTnT elevation included the right posterior, superior, and medial insula and the right inferior parietal lobule. Among patients with right middle cerebral artery infarction, the insular cluster was involved in 88% of patients with and 33% without cTnT elevation (odds ratio: 15.00; 95% CI: 2.65 to 84.79).

CONCLUSIONS

Infarctions in specific brain regions including the right insula are associated with elevated serum cardiac troponin T level indicative of myocardial injury.

Continuous antibiotic prophylaxis and cerebral spinal fluid infection in patients with intracranial pressure monitors

INTRODUCTION

Inconsistencies in the recommendation of prophylactic antibiotics for patients with intracranial pressure monitors compelled us to assess the effect of our standard regimen of continuous antibiotic prophylaxis on cerebrospinal fluid infection. We examined the rate, possible risk factors, causative organisms, and characteristics of infection.

METHODS

Three hundred eleven patients admitted between September 1998 and February 2001 with an intracranial pressure monitoring device in place were included. Two hundred eleven patients received a ventriculostomy, 95 an intraparenchymal fiber optic intracranial pressure monitor (ICPM), and 5 both an ICPM and a ventriculostomy.

RESULTS

The overall infection rate was 5.5% (17/311). No patient with an ICPM developed CSF infection. The infection rate among ventriculostomy patients was 8.1% (17/211). The majority of infections (82%) were caused by Gram-positive species. Younger age (OR=1.04 for each year, 95% CI=1.01-1.08, p=0.03) and increasing duration of ventriculostomy insertion (OR=1.2 for each day of catheter insertion, 95% CI=1.1-1.3, p<0.001) were risk factors for CSF infection in multivariate analysis. Infected patients experienced longer lengths of stay in the NICU (p<0.001) and hospital (p<0.001); however, infection did not impact clinical outcome, as measured by mortality and discharge GCS.

CONCLUSION

ICP monitors have a low overall infection rate. When infection occurs, gram positive organisms predominate. For patients with ventriculostomy, duration of catheter insertion strongly predicts infection, but did not alter in-hospital mortality.

Quetiapine in the Treatment of Behavioral Disturbances in Patients With Huntington’s Disease

The effect of quetiapine (an atypical antipsychotic with minimal extrapyramidal side effects) on motor as well as behavioral symptoms was studied in five consecutive patients with Huntington's disease in a long-term facility. Improvement of behavioral symptoms (i.e., psychotic symptoms, agitation, irritability, and insomnia) without worsening of motor functioning were noted.

Conversion of Ischemic Brain Tissue Into Infarction Increases With Age

Background and Purpose— Brain regions normal on diffusion-weighted imaging (DWI) but abnormal on mean transit time (MTT) maps represent tissue at risk of infarction, yet the fate of these regions is quite variable. The imperfect correlation between tissue outcome and initial imaging parameters suggests that each patient’s brain may have different susceptibility to ischemic stress. We hypothesize that age is a marker for tissue susceptibility to ischemia and thus plays a role in determining tissue outcome in human stroke.

Methods— Sixty patients with acute ischemic stroke and a region of DWI/MTT mismatch that was >20% of the DWI volume were included. All patients were scanned twice, within 12 hours of symptom onset and on day 5 or later. The percentage mismatch lost (PML) was calculated as percentage of initial DWI/MTT mismatch volume that was infarcted on the follow-up MRI. The statistical analysis explored relationships among the covariates age, Trial of Org 10172 in Acute Stroke Treatment (TOAST) subtypes, time-to-MRI, and initial DWI, MTT volume, mean arterial blood pressure and blood glucose level at admission, and previous history of hypertension and diabetes mellitus.

Results— Univariate comparisons showed that age ( P =0.003), hypertension ( P =0.009), and diabetes mellitus ( P =0.0002) were significantly associated with PML. Regression analyses showed age to be a significant covariate ( P =0.02). The regression model predicted a change in PML of ≈0.65% per year. The adjusted proportion of variance ( R 2 ) in PML that could be explained by age alone was 14%.

Conclusion— Age-dependent increase in conversion of ischemic tissue into infarction suggests that age is a biological marker for the variability in tissue outcome in acute human stroke.

Poor outcomes in patients who do not receive intravenous tissue plasminogen activator because of mild or improving ischemic stroke

BACKGROUND AND PURPOSE

Some patients with mild or improving ischemic stroke symptoms do not receive intravenous tissue plasminogen activator (tPA) because they look "too good to treat" (TGT); however, some have poor outcomes.

METHODS

We retrospectively analyzed data from a prospective single-center study between 2002 and 2004. TGT patients were those arriving within 3 hours of symptom onset and not treated with intravenous tPA solely because of mild or improving symptoms.

RESULTS

Of 128 patients presenting within 3 hours, 41 (34%) were not given tPA because of mild or improving stroke. Of the TGT patients, 11 of 41 (27%) died or were not discharged home because of neurological worsening (n=6) or persistent "mild" neurological deficit (n=5). No single variable at presentation was associated with death or lack of home discharge. There were 10 of 41 TGT patients (24%) who had > or =4-point improvement in National Institutes of Health Stroke Scale score before tPA decision; these patients were more likely to have subsequent neurological worsening (relative risk, 4.1, 95% CI, 1.1 to 15.4; P=0.05).

CONCLUSIONS

A substantial minority of patients deemed too good for intravenous tPA were unable to be discharged home. A re-evaluation of the stroke severity criteria for tPA eligibility may be indicated.

Neuroimaging of ischemia and infarction

Since the introduction of thrombolytic therapy as the foundation of acute stroke treatment, neuroimaging has rapidly advanced to empower therapeutic decision making. Diffusion-weighted imaging is the most sensitive and accurate method for stroke detection, and, allied with perfusion-weighted imaging, provides information on the functional status of the ischemic brain. It can also help to identify a response to thrombolytic and neuroprotective therapies. Additionally, multimodal magnetic resonance imaging, including magnetic resonance angiography, offers information on stroke mechanism and pathophysiology that can guide long-term medical management. Multimodal computed tomography is a comprehensive, cost-effective, and safe stroke imaging modality that can be easily implemented in the emergency ward and that offers fast and reliable information with respect to the arterial and functional status of the ischemic brain. Accessibility, contraindications, cost, speed, and individual patient-determined features influence which is the best imaging modality to guide acute stroke management.

Hypoattenuation on CT angiographic source images predicts risk of intracerebral hemorrhage and outcome after intra-arterial reperfusion therapy

BACKGROUND AND PURPOSE

Symptomatic hemorrhagic transformation (HT) is a significant complication of intravenous and catheter-based reperfusion. We hypothesized that the degree of vascular insufficiency, reflected as hypoattenuation on initial CT angiography (CTA) axial source images, is predictive of HT risk in stroke patients receiving intra-arterial reperfusion therapy.

METHODS

We examined initial CTA source images and follow-up CT scans in 32 consecutive patients. Regions of interest were semiautomatically segmented and reviewed. Mean intensity was determined in the region of maximal hypoattenuation and in normal contralateral tissue, and the arithmetic difference (deltaHU) calculated. Receiver operator characteristic (ROC) curves and cross-validation were used to identify threshold deltaHU values.

RESULTS

Thirteen patients had HT on follow-up CT (seven with parenchymal hematoma, six with hemorrhagic infarction). Patients with and those without HT did not differ in age, blood glucose level, lesion volume, or time to treatment or recanalization, though the former had a greater mean deltaHU (9.0 vs 6.3, P = .006). The ROC threshold at deltaHU > or = 8.1 was 69% sensitive and 90% specific for patients who developed HT (odds ratio = 19.1; 95% confidence interval: 2.9, 125; P = .002) and was predictive of poor clinical outcome (modified Rankin scale score > 2, P = .03). Neither HT in general nor parenchymal hematoma subtype was associated with poor outcome.

CONCLUSION

The degree of hypoattenuation on initial CTA source images is a risk factor for HT and poor clinical outcome after intra-arterial reperfusion therapy. Prospective validation of this relationship in large populations may permit feasible real-time risk stratification.

Transcranial Low-Frequency Ultrasound-Mediated Thrombolysis in Brain Ischemia

Background— Clinical studies using ultrasound at diagnostic frequencies in transcranial Doppler devices provided encouraging results in enhancing thrombolysis with tissue plasminogen activator (tPA) in acute stroke. Low-frequency ultrasound does not require complex positioning procedures, penetrates through the skull better, and has been demonstrated to accelerate thrombolysis with tPA in animal experiments in wide cerebrovascular territories without hemorrhagic side effects. We therefore conducted the first multicenter clinical trial to investigate safety of tPA plus low-frequency ultrasound (300 kHz).

Methods— Acute stroke patients within a 6-hour time window were included (National Institutes of Health Stroke Scale scores >4). Magnetic resonance imaging (MRI) was used to document vascular occlusion and to rule out cerebral hemorrhage. Patients were allocated to combination therapy alternately; the first patient received tPA only, the second patient received tPA plus ultrasound, etc. Follow-up included serial MRI directly thereafter and 24 hours later to confirm recanalization and tissue imaging. Clinical recovery was measured after treatment and 3 months later.

Results— 26 patients (70.4±9.7 years) entered the trial (12 tPA, 14 tPA plus ultrasound). The study was prematurely stopped because 5 of 12 patients from the tPA only group but 13 of 14 patients treated with the tPA plus ultrasound showed signs of bleeding in MRI ( P <0.01). Within 3 days of treatment, 5 symptomatic hemorrhages occurred within the tPA plus ultrasound group. At 3 months, neither morbidity nor treatment-related mortality or recanalization rates differed between both groups.

Conclusions— This study demonstrated bioeffects from low-frequency ultrasound that caused an increased rate of cerebral hemorrhages in patients concomitantly treated with intravenous tPA.

Magnetic resonance imaging: implication in acute ischemic stroke management

Multimodality magnetic resonance imaging (MRI) techniques, including diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI), fluid-attenuated inversion recovery (FLAIR), T2 susceptibility imaging, and magnetic resonance angiography (MRA), quickly provide accurate information about ischemic penumbra (DWI/PWI mismatch), tissue perfusion, and vascular localization in acute stroke setting. These techniques help physicians to select the proper candidates for thrombolysis and/or neuroprotective treatment to salvage tissue at risk (mismatch) and monitor acute stroke patients after treatment. Recent and ongoing trials demonstrate the benefit of treating acute stroke patients depending on tissue at risk of infarction rather than timing of onset. These techniques will extend timing to salvage ischemic brain tissue beyond the 3-hour window. MRI is a powerful tool for managing acute stroke patients and helps elucidate the pathophysiology of cerebral ischemia in a given patient.

A Pilot Study of Normobaric Oxygen Therapy in Acute Ischemic Stroke

Background and Purpose— Therapies that transiently prevent ischemic neuronal death can potentially extend therapeutic time windows for stroke thrombolysis. We conducted a pilot study to investigate the effects of high-flow oxygen in acute ischemic stroke.

Methods— We randomized patients with acute stroke (<12 hours) and perfusion-diffusion “mismatch” on magnetic resonance imaging (MRI) to high-flow oxygen therapy via facemask for 8 hours (n=9) or room air (controls, n=7). Stroke scale scores and MRI scans were obtained at baseline, 4 hours, 24 hours, 1 week, and 3 months. Clinical deficits and MR abnormalities were compared between groups.

Results— Stroke scale scores were similar at baseline, tended to improve at 4 hours (during therapy) and 1 week, and significantly improved at 24 hours in hyperoxia-treated patients. There was no significant difference at 3 months. Mean (±SD) relative diffusion MRI lesion volumes were significantly reduced in hyperoxia-treated patients at 4 hours (87.8±22% versus 149.1±41%; P =0.004) but not subsequent time points. The percentage of MRI voxels improving from baseline “ischemic” to 4-hour “non-ischemic” values tended to be higher in hyperoxia-treated patients. Cerebral blood volume and blood flow within ischemic regions improved with hyperoxia. These “during-therapy” benefits occurred without arterial recanalization. By 24 hours, MRI showed reperfusion and asymptomatic petechial hemorrhages in 50% of hyperoxia-treated patients versus 17% of controls ( P =0.6).

Conclusions— High-flow oxygen therapy is associated with a transient improvement of clinical deficits and MRI abnormalities in select patients with acute ischemic stroke. Further studies are warranted to investigate the safety and efficacy of hyperoxia as a stroke therapy.

SSRI and statin use increases the risk for vasospasm after subarachnoid hemorrhage

BACKGROUND

Use of medications with vasoconstrictive or vasodilatory effects can potentially affect the risk for vasospasm after aneurysmal subarachnoid hemorrhage (SAH).

METHODS

Using International Classification of Diseases-9 diagnostic codes followed by medical record review, the authors identified 514 patients with SAH admitted between 1995 and 2003 who were evaluated for vasospasm between days 4 and 14. The authors determined risks for vasospasm, symptomatic vasospasm, and poor clinical outcomes in patients with documented pre-hemorrhagic use of calcium channel blockers, beta-receptor blockers, ACE inhibitors, aspirin, selective serotonin reuptake inhibitors (SSRIs), non-SSRI vasoactive antidepressants, or statins.

RESULTS

Vasospasm developed in 62%, and symptomatic vasospasm in 29% of the cohort. On univariate analysis, the risk for all vasospasm tended to increase in patients taking SSRIs (p = 0.09) and statins (p = 0.05); SSRI use increased the risk for symptomatic vasospasm (p = 0.028). The Cochran-Armitage trend test showed that the proportion of patients taking SSRIs and statins increased significantly across three worsening categories (none, asymptomatic, symptomatic) of vasospasm. Logistic regression analysis showed that SSRI use tended to predict all vasospasm (O.R. 2.01 [0.91 to 4.45]), and predicted symptomatic vasospasm (O.R. 1.42 [1.06 to 4.33]). Statin exposure increased the risk for vasospasm (O.R. 2.75 [1.16 to 6.50]), perhaps from abrupt statin withdrawal (O.R. 2.54 [0.78 to 8.28]). Age < 50 years, Hunt-Hess grade 4 or 5, and Fisher Group 3 independently predicted all vasospasm, symptomatic vasospasm, poor discharge clinical status, and death.

CONCLUSION

Selective serotonin reuptake inhibitor and statin users have a higher risk for subarachnoid hemorrhage-related vasospasm. Whether the underlying disease indication, direct actions, or rebound effects from abrupt drug withdrawal account for the associated risk warrants further investigation.

Applying instance-based techniques to prediction of final outcome in acute stroke

OBJECTIVE

Acute cerebral stroke is a frequent cause of death and the major cause of adult neurological disability in the western world. Thrombolysis is the only established treatment of ischemic stroke; however, its use carries a substantial risk of symptomatic intracerebral hemorrhage. A clinical tool to guide the use of thrombolysis would be very valuable. One of the major goals of such a tool would be the identification of potentially salvageable tissue. This requires an accurate prediction of the extent of infarction if untreated. In this study, we investigate the applicability of highly flexible instance-based (IB) methods for such predictions.

METHODS AND MATERIALS

Based on information obtained from magnetic resonance imaging of 14 patients with acute stroke, we explored three different implementations of the IB method: k-NN, Gaussian weighted, and constant radius search classification. Receiver operating characteristics analysis, in particular area under the curve (AUC), was used as performance measure.

RESULTS

We found no significant difference (P = 0.48) in performance for the optimal k-NN (k = 164, AUC = 0.814 +/- 0.001) and Gaussian weight (sigma = 0.17, AUC = 0.813 +/- 0.001) implementations, while they were both significantly better (P < 1 x 10(-6) for both) than the constant radius implementation (R = 0.28, AUC = 0.809 +/- 0.001). Qualitative analyses of the distribution of instances in the feature space indicated that non-infarcted instances tends to cluster together while infarcted instances are more dispersed, and that there may not exist a stringent boundary separating infarcted from non-infarcted instances.

CONCLUSIONS

This study shows that IB methods can be used, and may be advantageous, for predicting final infarct in patients with acute stroke, but further work must be done to make them clinically applicable.

Arterial occlusion revealed by CT angiography predicts NIH stroke score and acute outcomes after IV tPA treatment

BACKGROUND AND PURPOSE

The relationship between location of occlusion and clinical outcome is poorly understood in patients receiving intravenous tissue-type plasminogen activator (IV tPA). We postulated that acute stroke patients receiving IV tPA with patent vasculature or occult arterial occlusion by CT angiography (CTA) would have better outcomes and decreased hemorrhagic risk.

METHODS

We identified 47 patients from our prospective stroke database who underwent CTA before treatment with IV tPA. Site of occlusion was categorized as M1 segment of the middle cerebral artery, M2 segment, multiple (either carotid, basilar, or both middle and anterior cerebral arteries), or absent (no occlusion proximal to M3). The effect of site of occlusion on National Institutes of Health Stroke Scale (NIHSS), early improvement (> or = 4-point improvement in NIHSS at 24 hours after treatment), intracranial hemorrhages, and modified Rankin scale (mRS) at 7 days was tested in a multivariate analysis.

RESULTS

The location of occlusion correlated with initial NIHSS for multiple, M1, M2 and absent occlusions (median NIHSS scores were 18, 18, 15, 10, respectively) (P < .02, rank sum). Following adjustment for initial NIHSS, age, and time to treatment, the absence of occlusion remained associated with early improvement (OR 5.0, 95% CI 1.1-23.3; P = .04) and independence at day 7 (mRS < or = 2) (OR 6.8, 95% CI 1.3-34.6; P = .02). Overall prevalence of symptomatic hemorrhages was 6.4%. Patients without occlusion had no hemorrhages (0% versus 23.3%; P < .04).

CONCLUSION

Among patients treated with tPA, those with patent vasculature or occult distal occlusion on CTA before treatment have lower NIHSS, better chances of early improvement and early independence with fewer hemorrhages.

Cooling for Acute Ischemic Brain Damage (COOL AID): a feasibility trial of endovascular cooling

OBJECTIVE

To report results of a randomized pilot clinical feasibility trial of endovascular cooling in patients with ischemic stroke.

METHODS

Forty patients with ischemic stroke presenting within 12 hours of symptom onset were enrolled in the study. An endovascular cooling device was inserted into the inferior vena cava of those randomized to hypothermia. A core body temperature of 33 degrees C was targeted for 24 hours. All patients underwent clinical assessment and MRI initially, at days 3 to 5 and days 30 to 37.

RESULTS

Eighteen patients were randomized to hypothermia and 22 to receive standard medical management. Thirteen patients reached target temperature in a mean of 77 +/- 44 minutes. Most tolerated hypothermia well. Clinical outcomes were similar in both groups. Mean diffusion-weighted imaging (DWI) lesion growth in the hypothermia group (n = 12) was 90.0 +/- 83.5% compared with 108.4 +/- 142.4% in the control group (n = 11) (NS). Mean DWI lesion growth in patients who cooled well (n = 8) was 72.9 +/- 95.2% (NS).

CONCLUSIONS

Induced moderate hypothermia is feasible using an endovascular cooling device in most patients with acute ischemic stroke. Further studies are needed to determine if hypothermia improves outcome.