Rationale and design of a randomized trial of early intensive blood pressure lowering on cerebral perfusion parameters in thrombolysed acute ischemic stroke patients

BACKGROUND AND RATIONALE

Uncertainty persists over the optimal management of blood pressure (BP) in the early phase of acute ischemic stroke (AIS). This study aims to determine the safety and effects of intensive BP lowering on cerebral blood flow (CBF) and functional in AIS patients treated with intravenous thrombolysis.

METHODS

In a randomized controlled trial, 54 thrombolysed AIS patients with a systolic BP of 160 to 180 mm Hg will be randomized to early intensive BP lowering (systolic target range 140-160 mm Hg) or guideline-based BP management (systolic range 160-180 mm Hg) during first 72-hours using primarily intravenous labetalol. We hypothesize that early intensive BP lowering will not reduce CBF by 20% and/or increase the volume of hypoperfused tissue by >20% on computed tomographic perfusion. Clinical outcome will be assessed using a dichotomized modified Rankin scale (scores 0-1 as excellent outcome vs scores 2-6 as dead or dependent) at 90 days. Other outcome would be symptomatic intracerebral hemorrhage. The trial is registered at ClinicalTrials.gov, NCT03443596.

CONCLUSION

This randomized study will provide important information about the physiological effects of BP reduction on cerebral perfusion after intravenous thrombolysis in AIS.

Abstract 147: Plaque Inflammation is Associated With Early Cerebral Ischemic Events in Symptomatic Carotid Stenosis

Background and aims: Currently, the severity of the symptomatic carotid stenosis determines the treatment approach. However, it explains only the regional hypoperfusion as the mechanism of cerebral ischemia. Artery-to-artery embolisation remains an important pathogenic mechanism in patients with high-risk carotid plaques. Recently, inflammation has been proposed as the initiating event for plaque rupture and cerebral embolism. Using 18F-fluorodeoxyglucose positron-emission tomography (FDG-PET)/computed tomography (CT) and high resolution magnetic resonance imaging (HR-MRI), we investigated the role of plaque imaging and stroke recurrence in our cohort of patients with recently symptomatic carotid stenosis.

Methods: This ongoing prospective study included consecutive patients within 30-days of recent stroke and ipsilateral carotid stenosis (≥50%). FDG uptake was quantified as mean standardized uptake values (SUV, g/ml). The ratio of T1 hyperintensity of carotid plaque to the ipsilateral sternocleidomastoid muscle (SCM) was recorded on T1-weighted fat suppressed HR-MRI. Patients were followed prospectively for stroke recurrence within 90-days.

Results: Of the 70 patients included in the study, 11 (16%) suffered from recurrent cerebral ischemic event in the same vascular territory within 90-days. Compared to patients without subsequent cerebral ischemic events, patients with recurrent cerebral ischemia showed higher mean T1 carotid-SCM ratio (2.24 versus 1.46; p<0.0001) and higher mean SUV value in the carotid plaque (3.26g/ml versus 1.28g/ml; p<0.0001). Higher T1 carotid-SCM ratio on HR-MRI (OR 3.374, 95%CI 1.561-6.253; p<0.0001), higher mean SUV on FDG-PET (OR 3.646, 95%CI 3.172-11.524; p=0.005) were independent predictors of recurrent cerebral ischemia.

Conclusions: FDG-PET/CT and HR-MRI of carotid stenosis helps in identification of patients at higher risk of subsequent cerebral ischemic events and may aid in better therapeutic decision-making.

Abstract TMP35: Clinical Stroke Scales in Predicting Large Vessel Occlusion: A Metaanalysis

Background: Identifying large vessel occlusion (LVO) is paramount in the era of endovascular therapy. This can be achieved easily by computed tomography angiogram(CTA) and magnetic resonance angiography(MRA). National Institute Health Stroke Scale(NIHSS) threshold can be used in primary stroke centre(PSC) without these facilities, to identify patients with LVO for transfer to a comprehensive stroke centre (CSC) for mechanical thrombectomy. Alternatively, simplified clinical stroke scales (CSS)can also be used by emergency medical services (EMS) to identify such patients to be directly transported to CSC. We aim to compare various CSS in predicting LVO in ischemic stroke.

Methods: We searched PUBMED from January 2005 to July 2016 and screened reference lists of included studies, and included all diagnostic accuracy studies that investigate CSS and prediction of LVO confirmed with CTA or MRA. Two authors independently screened titles and abstracts and perform data extraction for analysis. Pooled sensitivity, specificity and diagnostic odd ratio (DOR) of various CSS were obtained using the random effects model.

Result: 8 studies (total 8556 patients) were included for meta-analysis of 3 CSS. This includes the NIHSS≥5, ≥6, ≥10, ≥13; Cincinnati Prehospital Stroke Scale (CPSS)≥2 and Rapid Arterial oCclusion Evaluation (RACE) ≥ 5. Pooled sensivity and specificty for the respective cut off values of these CSS was metaanalysed and presented in table 1. NIHSS≥13 has the highest DOR (26.0), followed by NIHSS≥5 (16.9); whereas other NIHSS thresholds, CPSS and RACE were less predictive. NIHSS≥5 was found to have the highest sensitivity of 0.865 and NIHSS≥13 had the highest specificity of 0.934.

Conclusion: We found 2 NIHSS thresholds that were most useful for identifying LVO. Depending on resources and preferences of each stroke centre, different NIHSS threshold can be utilized for purpose of ruling in LVO using a high NIHSS threshold, or ruling out LVO using a low NIHSS threshold.

Abstract TMP119: Early Cerebral Ischemic Events in Symptomatic Carotid Stenosis are Related to Plaque Inflammation

Background and aims: Symptomatic carotid stenosis is associated with an increased risk of early stroke recurrence. Severity of the stenosis, current basis of revascularization, explains only the cerebral ischemic mechanism of regional hypoperfusion. Plaque inflammation, the initiating event for plaque rupture and thromboembolism (artery-to-artery embolism), is not evaluated routinely. Using 18F-fluorodeoxyglucose positron-emission tomography (FDG-PET)/computed tomography (CT) and high resolution magnetic resonance imaging (HR-MRI), we investigated the role of plaque imaging and stroke recurrence in our cohort of stroke patients with recently symptomatic carotid stenosis.

Methods: This ongoing prospective study included consecutive patients within 30-days of recent stroke and ipsilateral carotid stenosis (≥50%). FDG uptake was quantified as mean standardized uptake values (SUV, g/ml). The ratio of T1 hyperintensity of carotid plaque to the ipsilateral sternocleidomastoid muscle (SCM) was recorded on T1-weighted fat suppressed images. Patients were followed prospectively for stroke recurrence within 90-days. Embolic potential of carotid plaque is estimated by presence of spontaneous microembolic signals (MES) on extended transcranial Doppler monitoring of ipsilateral middle cerebral artery.

Results: Of the 33 patients included in the study, 6 (18%) suffered from recurrent cerebral ischemic event in the same vascular territory within 90-days. Compared to patients without subsequent cerebral ischemic events, patients with recurrent cerebral ischemia showed higher mean T1 carotid-SCM ratio (2.49 versus 1.53; p<0.0001) and higher mean SUV value in the carotid plaque (3.52g/ml versus 1.51g/ml; p<0.0001). Higher T1 carotid-SCM ratio on HR-MRI (OR 4.249, 95%CI 1.818-5.18; p<0.0001), higher mean SUV on FDG-PET (OR 3.050, 95%CI 5.586-28.571; p=0.005) and MES on TCD (OR 2.186, 95%CI 1.652-47.619;p=0.037) were independent predictors of recurrent cerebral ischemia.

Conclusions: FDG-PET/CT and HR-MRI imaging of carotid stenosis helps in identification of patients at higher risk of subsequent cerebral ischemic events and may aid in better therapeutic decision-making.

Abstract TP316: Early Decompressive Hemicraniectomy for Malignant Middle Cerebral Artery Infarction in Asian Patients

Background and purpose: Decompression craniectomy in acute malignant middle cerebral artery (MCA) ischemic stroke (IS) reduces mortality. However, its role in reducing disability in this group of patients is often questioned in the stroke community since previous studies have employed variable time intervals for surgical decompression as well as criteria for defining severe disability. We evaluated our Asian cohort of acute IS patients for determining the factors associated with favorable functional outcome.

Methods: Data for all acute IS patients hospitalized to our tertiary center were entered into a prospectively maintained registry. In this retrospective analysis, data for all malignant MCA IS patients who underwent decompressive hemicraniectomy were extracted. Various demographic, clinical and neuroimaging factors were analyzed for identifying independent predictors of favorable functional outcome at 6 months, which was defined as modified Rankin Scale of 0-3.

Results: From January 2005 to December 2014, a total of 75 patients with anterior circulation IS underwent decompressive hemicraniectomy. Median age was 55 years (IQR 44-64) with male preponderance (66%) and median NIH Stroke Scale (NIHSS) score 21 points (IQR 18-24). Considerable proportion of them (60%) received intravenous thrombolysis with tissue plasminogen activator (IV-tPA). Majority (70%) of patients suffered from acute right MCA IS and median time from symptom-onset to surgery was 31 hours (range18-51). Decompressive surgery was performed within 48 hours of symptom-onset in 50 (67%) of the patients. Favorable functional outcome was achieved by 25 (33.3%) patients at 6 months. Right sided stroke (OR 5.333; 95% CI 1.359- 20.927, p=0.016 ) and early decompression surgery (performed within 48 hours from symptom-onset (OR 3.636; 95% CI 1.032- 12.809, p=0.045 ) were independent predictors of favorable functional outcome at 6 months.

Conclusion: Early decompression craniectomy, especially in right MCA ischemic stroke is associated with better favorable functional outcome at 6 months.

Abstract TP443: Early Cognitive Decline in Patients with Symptomatic Carotid Stenosis is Related to Plaque Inflammation and Concomitant Intracranial Stenosis

Background and aims: Symptomatic carotid stenosis is associated with an increased risk of early stroke recurrence. Post-stroke vascular cognitive impairment is highly prevalent with significant functional consequences. However, reliable biomarkers for early prediction of cognitive decline are not well established. We postulated that regional hypoperfusion due to carotid stenosis would impair cognitive performance. Hence, we evaluated the cognitive parameters at baseline and their natural course during 90-days of follow up.

Methods: This ongoing prospective study included consecutive patients within 30-days of recent stroke and ipsilateral carotid stenosis (≥50%). Data regarding demographics and vascular risk factors were recorded. Cognitive parameters were assessed with the 30-point mini-mental scale (MMSE) and Montreal Cognitive Assessment (MoCA). All patients underwent carotid duplex sonography and 18-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET) of carotid arteries. Embolic potential of the carotid plaque is estimated by presence of spontaneous microembolic signals (MES) on extended transcranial Doppler monitoring of the middle cerebral arteries. Patients are followed prospectively for change in cognitive parameters.

Results: Of the 33 patients included in this study, 7 (21%) demonstrated deterioration of their cognitive parameters (MMSE in 4, MOCA in 5 and both in 6) during 90-day follow up. Only high Standard Uptake Value (SUV) on PET (3.62g/ml in cognitive-deterioration group versus 1.72g/ml in the unaffected group; p=0.01) and presence of concomitant intracranial stenosis (p=0.01) were associated with cognitive deterioration. Of the 7 cases who underwent carotid revascularization, 5 (71%) demonstrated improved cognitive performance at day-90.

Conclusions: Early cognitive decline is common among patients with symptomatic stenosis of the extracranial carotid artery, especially when associated with concomitant intracranial stenosis and plaque inflammation.

Good Intracranial Collaterals Trump Poor ASPECTS (Alberta Stroke Program Early CT Score) for Intravenous Thrombolysis in Anterior Circulation Acute Ischemic Stroke

BACKGROUND AND PURPOSE

In acute ischemic stroke, large early infarct size estimated by the Alberta Stroke Program Early CT Score (ASPECTS) is associated with poorer outcomes and is a relative contraindication for recanalization therapies. The state of the intracranial collateral circulation influences the functional outcome and may be a variable to consider before thrombolysis. We evaluated the prognostic effect of the collateral circulation in patients with thrombolyzed acute ischemic stroke who have large early infarct sizes as indicated by low ASPECTS.

MATERIALS AND METHODS

Patients with anterior circulation acute ischemic stroke who received a computed tomographic angiogram and subsequent treatment with intravenous tissue-type plasminogen activator from 2010 to 2013 were studied. Two independent neuroradiologists determined their ASPECTS. We stratified patients using ASPECTS into 2 groups: large volume infarcts (ASPECTS≤7 points) and small volume infarcts (ASPECTS 8-10). In addition, we evaluated a third group with very large volume infarcts (ASPECTS≤5 points). We then analyzed the 3 subgroups using the Maas, Tan, and ASPECTS-collaterals grading systems of the computed tomographic angiogram intracranial collaterals. Good outcomes were defined by modified Rankin Scale score of 0 to 2 at 3 months.

RESULTS

A total of 300 patients were included in the final analysis. For patients with very large volume infarcts (ASPECTS≤5 points), univariable analysis showed that younger age, male sex, lower National Institute of Health Stroke Scale (NIHSS), lower systolic blood pressure, and good collaterals by Maas, Tan, or ASPECTS-collaterals grading were predictors of good outcomes. On multivariate analysis, younger age (odds ratio, 0.93; 95% confidence interval, 0.89-0.97; P=0.002) and good collaterals by ASPECTS-collaterals system (odds ratio, 1.34; 95% confidence interval, 1.15-1.57; P<0.001) were associated with good outcomes.

CONCLUSIONS

In patients with large and very large volume infarcts, good collaterals as measured by the ASPECTS-collaterals system is associated with improved outcomes and can help select patients for intravenous thrombolysis.

Intravenous Thrombolysis for Acute Ischemic Stroke due to Cervical Internal Carotid Artery Occlusion

BACKGROUND

Internal carotid artery (ICA) occlusions are poorly responsive to intravenous thrombolysis with tissue plasminogen activator (IV-tPA) in acute ischemic stroke (AIS). Most study populations have combined intracranial and extracranial ICA occlusions for analysis; few have studied purely cervical ICA occlusions. We evaluated AIS patients with acute cervical ICA occlusion treated with IV-tPA to identify predictors of outcomes.

METHODS

We studied 550 consecutive patients with AIS who received IV-tPA and identified 100 with pure acute cervical ICA occlusion. We evaluated the associations of vascular risk factors, National Institutes of Health Stroke Scale (NIHSS) score, and leptomeningeal collateral vessel status via 3 different grading systems, with functional recovery at 90 days, mortality, recanalization of the primary occlusion, and symptomatic intracranial hemorrhage (SICH). Modified Rankin Scale score 0-1 was defined as an excellent outcome.

RESULTS

The 100 patients had mean age of 67.8 (range 32-96) and median NIHSS score of 19 (range 4-33). Excellent outcomes were observed in 27% of the patients, SICH in 8%, and mortality in 21%. Up to 54% of the patients achieved recanalization at 24 hours. On ordinal regression, good collaterals showed a significant shift in favorable outcomes by Maas, Tan, or ASPECTS collateral grading systems. On multivariate analysis, good collaterals also showed reduced mortality (OR .721, 95% CI .588-.888, P = .002) and a trend to less SICH (OR .81, 95% CI .65-1.007, P = .058). Interestingly, faster treatment was also associated with favorable functional recovery (OR 1.028 per minute, 95% CI 1.010-1.047, P = .001).

CONCLUSIONS

Improved outcomes are seen in patients with early acute cervical ICA occlusion and better collateral circulation. This could be a valuable biomarker for decision making.

How temporal evolution of intracranial collaterals in acute stroke affects clinical outcomes

OBJECTIVE

We compared intracranial collaterals on pretreatment and day 2 brain CT angiograms (CTA) to assess their evolution and relationship with functional outcomes in acute ischemic stroke (AIS) patients treated with IV tissue plasminogen activator (tPA).

METHODS

Consecutive AIS patients who underwent pretreatment and day 2 CTA and received IV tPA during 2010-2013 were included. Collaterals were evaluated by 2 independent neuroradiologists using 3 predefined criteria: the Miteff system, the Maas system, and 20-point collateral scale by the Alberta Stroke Program Early CT Score methodology. We stratified our cohort by baseline pre-tPA state of their collaterals and by recanalization status of the primary vessel for analysis. Good outcomes at 3 months were defined by a modified Rankin Scale score of 0-1.

RESULTS

This study included 209 patients. Delayed collateral recruitment by any grading system was not associated with good outcomes. All 3 scoring systems showed that collateral recruitment on the follow-up CTA from a baseline poor collateral state was significantly associated with poor outcome and increased bleeding risk. When the primary vessel remained persistently occluded, collateral recruitment was significantly associated with worse outcomes. Interestingly, collateral recruitment was significantly associated with increased mortality in 2 of the 3 grading systems.

CONCLUSIONS

Not all collateral recruitment is beneficial; delayed collateral recruitment may be different from early recruitment and can result in worse outcomes and higher mortality. Prethrombolysis collateral status and recanalization are determinants of how intracranial collateral evolution affects functional outcomes.

Abstract 151: Vascular Events Occur More Frequently In Stroke Patients With Lower Concentrations of Vitamin D: A Prospective Cohort Analysis

Introduction: Vitamin D deficiency has been implicated in vascular dysfunction and the risk of recurrent vascular events. Previous studies, limited by a small sample size and lack of comparisons with long-term events, have yielded discordant results. To assess the hypothesis that low vitamin D levels predict long-term vascular events in patients with ischemic stroke, we conducted a large hospital-based study to compare the association between baseline vitamin D levels and the subsequent risk of vascular events.

Methods: Between January 2010 and July 2011, 590 participants (mean age, 60.7 years; 69% men) diagnosed with ischemic stroke and transient ischemic attack at the National University Hospital, Singapore, were prospectively followed for vascular events (recurrent stroke, myocardial infarction and vascular death). Serum 25-hydroxyvitamin D levels were determined using the Roche Cobas e411 analyzer. Cox proportional hazards models were used to assess the associations between quartiles of serum 25-hydroxyvitamin D and the risk of vascular events, which were adjusted for demographic, stroke severity and subtype, and vascular risk factor covariates.

Results: During a mean follow-up of 3.2 years (1,190 person-year), 116 participants developed a recurrent vascular event (recurrent stroke, n=63; myocardial infarction, n=30; vascular death, n=23). Using Cox proportional hazards models, the multivariate adjusted hazard ratios (95% confidence interval) for recurrent vascular events in participants with lower levels of serum 25-hydroxyvitamin D (<14.9 mmol/l, 14.9-21.4 mmol/l and 21.5-28.9 mmol/l) were 1.43 (0.81-2.55), 1.70 (0.97-2.91) and 2.09 (1.22-3.58) compared to participants with higher concentrations (>28.9 mmol/l). Kaplan-Meier plots for unadjusted rates of vascular events show clear differences in risk by quartiles of serum 25-hydroxyvitamin D after a year of follow-up.

Conclusions: Our results support the association between vitamin D deficiency and increased risk of recurrent vascular events in patients with ischemic stroke. Clinical trials are needed to ascertain whether correcting for this deficiency could indeed reduce the burden of vascular events in these individuals.

Assessment of intracranial collaterals on CT angiography in anterior circulation acute ischemic stroke

BACKGROUND AND PURPOSE

Intracranial collaterals influence the prognosis of patients treated with intravenous tissue plasminogen activator in acute anterior circulation ischemic stroke. We compared the methods of scoring collaterals on pre-tPA brain CT angiography for predicting functional outcomes in acute anterior circulation ischemic stroke.

MATERIALS AND METHODS

Two hundred consecutive patients with acute anterior circulation ischemic stroke treated with IV-tPA during 2010-2012 were included. Two independent neuroradiologists evaluated intracranial collaterals by using the Miteff system, Maas system, the modified Tan scale, and the Alberta Stroke Program Early CT Score 20-point methodology. Good and extremely poor outcomes at 3 months were defined by modified Rankin Scale scores of 0-1 and 5-6 points, respectively.

RESULTS

Factors associated with good outcome on univariable analysis were younger age, female sex, hypertension, diabetes mellitus, atrial fibrillation, small infarct core (ASPECTS ≥8), vessel recanalization, lower pre-tPA NIHSS scores, and good collaterals according to Tan methodology, ASPECTS methodology, and Miteff methodology. On multivariable logistic regression, only lower NIHSS scores (OR, 1.186 per point; 95% CI, 1.079-1.302; P = .001), recanalization (OR, 5.599; 95% CI, 1.560-20.010; P = .008), and good collaterals by the Miteff method (OR, 3.341; 95% CI, 1.203-5.099; P = .014) were independent predictors of good outcome. Poor collaterals by the Miteff system (OR, 2.592; 95% CI, 1.113-6.038; P = .027), Maas system (OR, 2.580; 95% CI, 1.075-6.187; P = .034), and ASPECTS method ≤5 points (OR, 2.685; 95% CI, 1.156-6.237; P = .022) were independent predictors of extremely poor outcomes.

CONCLUSIONS

Only the Miteff scoring system for intracranial collaterals is reliable for predicting favorable outcome in thrombolyzed acute anterior circulation ischemic stroke. However, poor outcomes can be predicted by most of the existing methods of scoring intracranial collaterals.

External validation of the Boston Acute Stroke Imaging Scale and M1-BASIS in thrombolyzed patients

BACKGROUND AND PURPOSE

Radiological findings play an essential role in therapeutic decision making and prognostication in acute ischemic stroke (AIS). The Boston Acute Stroke Imaging Scale (BASIS) and Middle Cerebral Artery-BASIS (M1-BASIS) methodologies are rapid purely radiological instruments and easily applicable for patients with AIS. We validated these methods in patients with AIS treated with intravenous tissue-type plasminogen activator.

METHODS

For BASIS, patients were labeled as having major stroke if there was occlusion of distal internal carotid artery, proximal (both M1 and M2 segments) of middle cerebral artery or the basilar artery, or an Alberta Stroke Program Early CT Score≤7. M1-BASIS differs from BASIS by classifying AIS patients with M2 occlusion as a minor stroke. We evaluated these classification systems for predicting functional outcomes (modified Rankin Scale score 0-1) at 3 months.

RESULTS

Two hundred sixty-five consecutive AIS patients treated with intravenous tissue-type plasminogen activator were included. On multivariate analysis, younger age (odds ratio, 1.039, 95% confidence interval, 1.009-1.070; P=0.011), lower National Institutes of Health Stroke Scale score (odds ratio, 1.140; 95% confidence interval, 1.073-1.210; P<0.001), and minor stroke by M1-BASIS (odds ratio, 2.376; 95% confidence interval, 1.047-5.393; P=0.039) were independent predictors of good functional outcome. When compared with National Institutes of Health Stroke Scale, the receiver operating characteristic curves for both BASIS (area under the curve, 0.721) and M1-BASIS (area under the curve, 0.795) correlated well with clinical severity scores. M1-BASIS has an additive effect with the National Institutes of Health Stroke Scale score to predict good outcomes.

CONCLUSIONS

The purely radiological M1-BASIS correlates well with the clinical severity of stroke and can be a reliable prognostication tool in thrombolyzed AIS patients. This system might find an important place in the current era of telestroke.

Association between reversible cerebral vasoconstriction syndrome and thrombotic thrombocytopenic purpura

BACKGROUND

Reversible cerebrovascular constriction syndrome (RCVS) presents with thunderclap headache and ischemic neurological deficits due to focal vasoconstrictions in major intracranial arteries. Reversibility of focal vasoconstrictions is the hallmark of RCVS. The commonest conditions associated with RCVS are a post-partum state and administration of vasoactive agents.

METHODS

We describe a series of 3 cases of thrombotic thrombocytopenic purpura (TTP) who presented with thunderclap headache and focal neurological deficits.

RESULTS

Vascular imaging revealed focal areas of constrictions in multiple intracranial arteries. All cases were treated with plasmapheresis and serial transcranial Doppler (TCD) and magnetic resonance angiography revealed resolution of cerebral vasoconstriction, accompanied by clinical recovery.

CONCLUSION

RCVS should be considered in patients with TTP who presented with thunderclap headache. TCD is an important tool for monitoring the course of cerebral vasoconstriction in TTP.

Internal cerebral vein asymmetry on follow-up brain computed tomography after intravenous thrombolysis in acute anterior circulation ischemic stroke is associated with poor outcome

BACKGROUND

Identifying early predictors of functional outcome after acute ischemic stroke (AIS) is important for planning rehabilitation strategies. Internal cerebral veins (ICV) drain deep parts of brain, run parallel to each other, and consistently seen on computed tomography angiography (CTA). Even minor asymmetry in their filling can be identified. We hypothesized that venous drainage would be impaired in patients with acute occlusion of internal carotid artery or middle cerebral artery. Because systemic thrombolysis can alter the vascular findings, we evaluated the relationship between ICV asymmetry on follow-up CTA and functional outcome.

METHODS

Consecutive AIS patients treated with intravenous thrombolysis between 2007 and 2010 were included. ICV asymmetry was assessed by 2 independent blinded stroke neurologists/neuroradiologists. Functional outcome was assessed by the modified Rankin Scale (mRS) at 3 months, dichotomized as good (0-1) and poor (2-6). Data were analyzed for predictors of functional outcome.

RESULTS

Of 2238 patients with AIS, 226 (10.1%) anterior circulation AIS patients received intravenous thrombolysis. The median age was 65 years (range 19-92), 44% were men, and median National Institutes of Health Stroke Scale (NIHSS) score was 16 points (range 4-32). Hypertension was the commonest risk factor in 173 (76.5%) patients, whereas 78 (34.5%) had atrial fibrillation. ICV asymmetry on follow-up CTA was assessed in 103 (45.5%) patients. Admission NIHSS score (odds ratio [OR] 1.07; 95% confidence interval [CI] 1.079-1.201, P = .046), change in NIHSS score during first 24 hours (OR .737; 95% CI .672-.807, P < .0001), and ICV asymmetry on follow-up CTA (OR 20.3; 95% CI 4.67-52.07, P < .0001) independently predicted poor outcome at 3 months.

CONCLUSIONS

ICV asymmetry on follow-up CTA after intravenous thrombolysis is an early predictor of poor functional outcome.

Early and continuous neurologic improvements after intravenous thrombolysis are strong predictors of favorable long-term outcomes in acute ischemic stroke

BACKGROUND

Intravenously administered tissue plasminogen activator (IV tPA) remains the only approved therapeutic agent for arterial recanalization in acute ischemic stroke (AIS). Considerable proportion of AIS patients demonstrate changes in their neurologic status within the first 24 hours of intravenous thrombolysis with IV tPA. However, there are little available data on the course of clinical recovery in subacute 2- to 24-hour window and its impact. We evaluated whether neurologic improvement at 2 and 24 hours after IV tPA bolus can predict functional outcomes in AIS patients at 3 months.

METHODS

Data for consecutive AIS patients treated with IV tPA within 4.5 hours of symptom onset during 2007-2011 were prospectively entered in our thrombolyzed registry. National Institutes of Health Stroke Scale (NIHSS) scores were recorded before IV tPA bolus, at 2 and 24 hours. Early neurologic improvement (ENI) at 2 hours was defined as a reduction in NIHSS score by 10 or more points from baseline or an absolute score of 4 or less points at 2 hours. Continuous neurologic improvement (CNI) was defined as a reduction of NIHSS score by 8 or more points between 2 and 24 hours or an absolute score of 4 or less points at 24 hours. Favorable functional outcomes at 3 months were determined by modified Rankin Scale (mRS) score of 0-1.

RESULTS

Of 2460 AIS patients admitted during the study period, 263 (10.7%) received IV tPA within the time window; median age was 64 years (range 19-92), with 63.9% being men, a median NIHSS score of 17 points (range 5-35), and a median onset-to-treatment time of 145 minutes (range 57-270). Overall, 130 (49.4%) thrombolyzed patients achieved an mRS score of 0-1 at 3 months. The female gender, age, and baseline NIHSS score were found to be significantly associated with CNI on univariate analysis. On multivariate analysis, NIHSS score at onset and female gender (odds ratio [OR]: 2.218, 95% confidence interval [CI]: 1.140-4.285; P=.024) were found to be independent predictors of CNI. Factors associated with favorable outcomes at 3 months on univariate analysis were younger age, female gender, hypertension, NIHSS score at onset, recanalization on transcranial Doppler (TCD) monitoring or repeat computed tomography (CT) angiography, ENI at 2 hours, and CNI. On multivariate analysis, NIHSS score at onset (OR per 1-point increase: .835, 95% CI: .751-.929, P<.001), 2-hour TCD recanalization (OR: 3.048, 95% CI: 1.537-6.046; P=.001), 24-hour CT angiographic recanalization (OR: 4.329, 95% CI: 2.382-9.974; P=.001), ENI at 2 hours (OR: 2.536, 95% CI: 1.321-5.102; P=.004), and CNI (OR: 7.253, 95% CI: 3.682-15.115; P<.001) were independent predictors of favorable outcomes at 3 months.

CONCLUSIONS

Women are twice as likely to have CNI from the 2- to 24-hour period after IV tPA. ENI and CNI within the first 24 hours are strong predictors of favorable functional outcomes in thrombolyzed AIS patients.

Cerebral Hyperperfusion Syndrome After Superficial Temporal Artery-middle Cerebral Artery Bypass for Severe Intracranial Steno-occlusive Disease: A Case Control Study

BACKGROUND:

Intracranial stenoses carry increased risk for cerebral ischemia. We perform external carotid-internal carotid (EC-IC) artery bypass in our patients with severe stenosis of the intracranial internal carotid (ICA) or middle cerebral artery (MCA) with impaired cerebral vasodilatory reserve (CVR).

OBJECTIVE:

To evaluate cerebral hemodynamics and cerebral hyperperfusion syndrome (HPS) in patients who develop focal neurological deficits after EC-IC bypass surgery.

METHODS:

Patients with severe intracranial ICA or MCA stenosis and impaired CVR on transcranial Doppler (TCD) derived breath-holding index (BHI) were evaluated with acetazolamide-challenged technetium-99m hexamethylpropyleneamineoxime–single-photon emission computed tomography (SPECT). EC-IC bypass surgery was offered to patients with impaired CVR on SPECT. Close monitoring was performed in patients developing focal neurological deficits within 7 days of surgery.

RESULTS:

Of 112 patients with severe intracranial ICA/MCA stenosis, 77 (69%) showed impaired CVR and 46 (41%) underwent EC-IC bypass. Transient neurological deficits within 7 days of surgery developed in 8 (17%). HPS was confirmed by CT perfusion and/or SPECT in 7 cases. A strong correlation was observed between HPS and preoperative TCD-BHI values (0%, 6.3%, and 41% in patients with BHI 0.3-0.69, 0-0.3 and &lt;0, respectively; P = .012). HPS patients showed more than a 50% increase in MCA flow velocity on TCD (compared with preoperative values) on the operated side (63.3% vs 3.3% on control side, P &lt; .001). Meticulous control of blood pressure and hydration led to rapid and complete resolution of neurological deficits in all cases.

CONCLUSION:

Symptomatic cerebral HPS is common in the early postoperative period after EC-IC bypass surgery. Early diagnosis and appropriate management might prevent the complications of this syndrome.

Abstract WMP48: Usefulness of High-Resolution MRI in the Investigation of Intracranial Stenosis

Objective: High-resolution dark-blood MRI (HR-MRI) is recently applied for investigation of intracranial stenosis. We aim to study the usefulness of HR-MRI in a group of stroke patients with intracranial stenosis detected on TOF-MRA.

Methods: Consecutive patients with ischemic stroke or TIA presented to a teaching hospital in Singapore were recruited into a long-term follow-up study and underwent MRI of the brain including TOF-MRA with a 3T scanner at the convalescent stage. Symptomatic intracranial stenoses >/=50% were further investigated with T2 and T1 3-dimentional HR-MRI, and post-contrast T1 HR-MRI were also performed in subjects with normal renal function. Additional scan times required for HR-MRI were 6’22” for each of the non-contrast sequences and 4’33” for the post-contrast sequence.

Findings: 35 stroke patients underwent study MRI at a mean of 123 days after stroke onset, and 12 were found to have symptomatic stenoses on TOF-MRA. 2 of them did not reveal any obvious disease on HR-MRI, while intracranial stenoses were confirmed in 10 patients (mean age: 57 years, 8 were male). Distributions include 7 with M1 stenosis/occlusion, 1 with tandem petrous ICA and M1 stenoses, 1 with cavernous ICA stenosis and 1 with petrous ICA stenosis. HR-MRI were not evaluable in one patient with M1 stenosis due to movement artifacts, and for the distal petrous ICA stenosis in the patient with tandem stenoses due to susceptibility artifact from the paranasal sinus. For the remaining 9 symptomatic stenoses, HR-MRI provided additional information with better definition of the distribution and extent of plaques in all cases, reclassification of total occlusion to severe stenosis in 3 cases, demonstration of significant plaque enhancement in 5 of 6 cases when gadolinium was given, and detection of plaque in the asymptomatic contralateral artery in 4 cases.

Conclusion: HR-MRI is a promising technique that can reveal potentially useful information in the majority of patients with stroke due to intracranial stenosis. However, further technological advance to overcome the current limitations of long acquisition time and restricted brain coverage is required before adoption of this technique into routine clinical practice.

Persistence of hyperdense middle cerebral artery sign on follow-up CT scan after intravenous thrombolysis is associated with poor outcome

BACKGROUND

The rates and extent of recovery in acute ischemic stroke (AIS) patients treated with intravenous tissue plasminogen activator (IV-tPA) remain highly variable. Hyperdense middle cerebral artery sign (HMCAS) on pretreatment unenhanced computerized tomography (CT) of the brain represents the presence of thrombus, often associated with severe neurological deficits and poor clinical outcome at 3 months. However, HMCAS is reliable only in AIS patients managed conservatively. In patients treated with systemic thrombolysis, HMCAS may disappear (representing clot dissolution) or persist (persisting clot) on the follow-up CT scan of the brain. We aimed at evaluating whether disappearance or the persistence of HMCAS on follow-up CT scan of the brain can predict the final outcome at 3 months.

METHODS

Data from consecutive AIS patients treated with IV-tPA, in a standardized protocol, from January 2007 to March 2010 were included in the prospective thrombolysis registry at our tertiary care center. For this evaluation, posterior circulation stroke was excluded. HMCAS was assessed on admission as well as follow-up CT by 2 independent stroke neurologists, blinded to the patient data or outcomes. Functional outcomes assessed by the modified Rankin Scale (mRS) at 3 months were dichotomized as good (mRS score 0-1) and poor (mRS score 2-6). The data were analyzed for the early predictors of poor functional outcome with SPSS version 19 for Windows.

RESULTS

Of the total of 2,238 patients admitted during the study period, 226 (11%) with anterior circulation AIS treated with intravenous thrombolysis were included. Median age of the patients was 65 years (range 19-92), 63% were males and they had a median National Institutes of Health Stroke Scale (NIHSS) score of 16 points (range 4-32). HMCAS was observed on admission CT scan in 109 (48.2%) patients and persisted on follow-up CT in 52 (47.7%) of them. Overall, 108 (47.8%) patients achieved poor functional outcome at 3 months. Admission NIHSS score (OR per 1-point increase = 1.241; 95% CI = 1.151-1.337, p < 0.0005), lesser change in NIHSS score at 24 h (OR per 1-point reduction = 0.730; 95% CI = 0.666-0.800, p < 0.0005) and persistence of HMCAS on follow-up CT scan (OR = 3.352; 95% CI = 1.991-11.333, p = 0.039) were associated with poor outcome at 3 months.

CONCLUSION

Persistence of HMCAS on the follow-up CT scan of the brain in acute ischemic stroke patients treated with IV-tPA can be used as an early predictor of poor functional outcome.

Usefulness of CT angiography for therapeutic decision making in thrombolyzing intubated patients with suspected basilar artery thrombosis

BACKGROUND AND AIMS

Acute ischemic stroke (AIS) due to basilar artery thrombosis (BAT) causes high mortality and severe disability. Early neurological assessment and timely thrombolysis might improve outcome. BAT is difficult to diagnose due to wide spectrum of presentation and decreased conscious level. Emergency physicians often intubate BAT patients with airway compromise before arrival of stroke neurologist. We evaluated role of computerized tomography (CT) angiography (CTA) of brain and cervical arteries in early diagnosis of acute BAT in intubated patients and facilitating decision for thrombolysis.

METHODS

Consecutive AIS patients presenting between 2007 and 2009 within 6 hours of symptom onset, with sudden deterioration in conscious level and intubation before assessment by neurologist, were included. All patients underwent brain CT and CTA. Outcomes were assessed at 3 months.

RESULTS

Thrombolytic therapy, mainly intravenous tissue plasminogen activator (IV-TPA), was administered to 161 (8.4%) of 1,917 AIS patients during the study period. Acute BAT contributed 10.9% of our cohort. CTA was performed in 152 (94.4%) patients and the rest were excluded due to their impaired renal functions. Five patients (3 males, mean age 72 years) presenting with acute obtundation and airway compromise were intubated, sedated, and paralyzed before assessment by neurologist. CTA showed BAT in all. IV-TPA was initiated at 213 ± 59 minutes in 4 patients while 1 received intraarterial thrombolysis at 13 hours. There was no intracranial hemorrhage. Mean length of hospital stay was 11.8 days. Despite severe stroke at presentation, good functional recovery at 3 months (modified Rankin scale [mRS] 1) occurred in 2 patients; mRS 4 in 1, and 2 died.

CONCLUSION

In patients with BAT, intubated before assessment by neurologist, CTA might help in confirming the diagnosis and facilitating therapeutic decision making for initiating thrombolysis.

Abstract 3290: Timing Of Recanalization After Intravenous Thrombolysis Determines The Functional Outcomes In Acute Ischemic Stroke

Background and Purpose: Intravenously administered tissue plasminogen activator (IV-TPA) is the only approved therapeutic agent for arterial recanalization in acute ischemic stroke (AIS). Wide variations in rates and timing of neurological recovery are observed in thrombolyzed patients. Although, recanalization of acutely occluded intracranial artery remains the major aim IV-TPA, timing and impact of this phenomenon on functional outcomes has not been evaluated properly. We evaluated the relationship between the arterial patency and timing of recanalization with functional outcomes at 3-months in AIS.

Methods: Data for consecutive AIS patients treated with IV-TPA within 4.5 hours of symptom-onset during 2007-2010 were prospectively entered in the thrombolysis registry maintained at our tertiary care center. Data were collected for demographic characteristics, vascular risk factors, stroke subtypes and blood pressure before IV-TPA bolus. National Institute of Health Stroke Scale (NIHSS) scores were obtained before IV-TPA, at 2-hours and at 24-hours. Patients were continuously monitored with 2-MHz pulsed wave diagnostic transcranial Doppler (TCD) for 2-hours after IV-TPA bolus for early recanalization (ER). ER was assessed using the Thrombolysis in Brain Ischemia grading TCD system. Arterial patency was assessed on day 2 in patients who underwent CT angiography or magnetic resonance angiography, labeled as delayed recanalization (DR). Absence of recanalization on early TCD or imaging on day 2 was called persistent arterial occlusion (PAO). Favorable functional outcomes at 3 months were determined by modified Rankin scale (mRS) of 0-1.

Results: Of the 2238 AIS patients admitted during the study period, 240 (11%) received IV-TPA within 4.5-hours of symptom-onset. Median age was 65yrs (range 19-92), 63% males, median NIHSS 17points (range 3-35) and median onset-to-treatment time 149 minutes. Overall, 122 (50.8%) patients achieved favorable functional outcome at 3-months. Information about ER, DR and PAO was available for 160 patients- ER in 55(34.4%), DR in 44(27.5%) and PAO in 61(38.1%) patients. Timing of recanalization was associated with favorable outcome (ER 72.7%, DR 63.6% and PAO 31.1%; p<0.005). Factors associated with favorable outcome at 3-months on univariable analysis were younger age, female gender, atrial fibrillation, baseline NIHSS, onset-to-treatment time and timing of recanalization. However, on multivariable analysis, NIHSS at onset (OR per 1-point increase 0.907, 95%CI 0.848-0.969), ER (OR 3.32, 95%CI 1.295-9.474) and DR (OR 3.021 95%CI 1.197-7.634) were found as independent predictors of favorable outcome at 3-months.

Conclusions: Timing of arterial recanalization induced by IV-TPA in acute ischemic stroke is a strong predictor of favorable outcome at 3-months.

Abstract 3286: Persistently Reduced Venous Drainage After Intravenous Thrombolysis is Associated With Poor outcome in Acute Anterior Circulation Ischemic Stroke

Background- Significant numbers of acute ischemic stroke (AIS) patients recover with timely-administered intravenous tissue plasminogen activator (IV-TPA). However, rates and extent of recovery remain variable. Considering scarce and costly resources, early identification of reliable predictors for functional outcomes is important for planning rehabilitation strategies. We hypothesized that venous drainage would be impaired on the side of cerebral hypoperfusion due to acute occlusion of internal carotid or middle cerebral artery. The 2 internal cerebral veins (ICV) drain the deep parts of hemispheres and run backward to form great cerebral vein. Since ICVs are consistently seen on CT angiography (CTA), parallel and run very close to each other, even minor asymmetry in their filling can be easily diagnosed. ICV asymmetry in pre-TPA CTA can change in patients achieving arterial recanalization, rendering it less useful for predicting the long-term outcomes. Thus, we aimed at evaluating whether the presence of ICV asymmetry on follow-up CTA can predict the final outcome.

Methods- Data from consecutive AIS patients treated with IV-TPA, in a standardized protocol, from Jan2007 to March2010 were included in a prospective registry at our tertiary center. In this study, we excluded posterior circulation strokes. Significant proportion AIS patients undergo CTA on day 2 after IV-TPA to assess the status of arterial patency. ICV asymmetry was assessed by 2 independent stroke neurologists/ neuroradiologists, blinded to patient data or outcomes. Functional outcomes were assessed by modified Rankin Scale (mRS) at 3-months, dichotomized as good outcome (mRS 0-1) and poor outcome (mRS 2-6). Data were analyzed for the early predictors of function outcome.

Results- Of the total of 2238 patients admitted during the study period, 226 (10.1%) with anterior circulation AIS treated with intravenous thrombolysis were included. Median age was 65yrs (range 19-92), 63% males and median National Institute of Health Stroke Scale (NIHSS) 16points (range 4-32). Hypertension was the commonest vascular risk factor in 144 (76%) while 63 (33%) patients suffered from atrial fibrillation (AF). Overall, 108 (47.8%) patients achieved poor functional outcome at 3-months. ICV asymmetry could be assessed only in 103 (45.5%) patients on their follow up CTA films. Admission NIHSS score (OR1.08;95%CI 1.001-1.157,p=0.048) and ICV asymmetry on follow-up CT scan (OR 23.9;95%CI 5.15-63.99,p <0.0001) were associated with poor outcome at 3-months.

Conclusion- Presence of the asymmetry of internal cerebral veins on the follow up CT angiography in acute ischemic stroke patients treated with IV-TPA can be used as an early predictor of poor functional outcome.

Intravenous thrombolysis for acute ischemic stroke in Asia

Data regarding thrombolysis for acute ischemic stroke in Asia are scarce and only a small percentage of patients are thrombolysed. Clinical trials that led to the recommended dose of intravenously administered tissue plasminogen activator (IV-tPA) included predominantly Caucasian patients. However, the single-arm case-controlled observational studies in Japanese patients suggested the clinical efficacy and safety of low-dose IV-tPA (0.6 mg/kg bodyweight; maximum 60 mg) comparable with standard dose (0.9 mg/kg bodyweight; maximum 90 mg). There has been no randomized clinical trial for determining the dose, efficacy or safety of IV-tPA in Asia. Accordingly, the dose of IV-tPA in Asia remains controversial. Reduced treatment cost, lower symptomatic intracerebral hemorrhage risk and comparable efficacy encouraged many Asian centers to adopt low-dose or even variable-dose IV-tPA regimens. We present the current status of thrombolysis for acute ischemic stroke in Asia.

Abstract 3267: Persistence of Hyperdense Middle Cerebral Artery Sign on Follow-up CT Scan is Associated with Poor Outcome in Ischemic Stroke Patients Treated with Intravenous Thrombolysis

Background- Early identification of reliable predictors of functional outcomes is important for planning rehabilitation strategies in patients with acute ischemic stroke (AIS). Hyperdense middle cerebral artery sign (HMCAS) on unenhanced computerized tomography (CT) of the brain represents presence of thrombus, often associated with poor outcome at 3-months. In thrombolyzed cases, HMCAS may disappear or persist on the follow-up CT scan. We evaluated whether persistence of HMCAS on follow-up CT predicts functional outcome at 3-months.

Methods- Consecutive AIS patients treated with intravenous thrombolysis between 2007 and 2010 were included. HMCAS was assessed on admission as well as follow-up CT by 2 independent readers, blinded to patient data and outcomes. Data were analyzed for early predictors of poor functional outcome at 3months (modified Rankin scale 2-6points).

Results- Of the total of 2238 patients admitted during the study period, 226 (10.1%) with anterior circulation AIS treated with intravenous thrombolysis were included. Median age of the IV-TPA treated patients was 65yrs (range 19-92), 63% males and median National Institute of Health Stroke Scale (NIHSS) 16points (range 4-32). HMCAS was observed on admission CT scan in 109 (48.2%) patients and persisted on follow-up CT in 52 (47.7%) of them. Overall, 108 (47.8%) patients achieved poor functional outcome at 3-months. Older age (OR 1.024;95%CI0.999-1.048), admission NIHSS score (OR1.08;95%CI 1.03-1.14,p=0.002) and HMCAS on follow-up CT scan (OR 10.25;95%CI 4.05-25.99,p <0.0001) were associated with poor outcome at 3-months.

Conclusion- Persistence of HMCAS on the follow up CT scan in AIS patients receiving intravenous thrombolysis is an early predictor of poor functional outcome at 3-months.

Abstract 3275: Early Neurological Improvement After Intravenous Thrombolysis in Acute Stroke Predicts Long-Term Functional Outcome

Background: Intravenously administered tissue plasminogen activator (IV-TPA) remains the only approved therapeutic agent for arterial recanalization in acute ischemic stroke (AIS). Wide variations in the rates and timing of neurological recovery are observed in thrombolyzed patients. While all IV-TPA treated patients are routinely evaluated for neurological recovery at 24-hours, considerable improvement occurs in some cases within 2-hours of treatment initiation. We evaluated whether early neurological improvement at 2-hours after IV-TPA bolus (ENI-2) can predict functional outcomes in thrombolyzed AIS patients at 3-months.

Methods: Data for consecutive stroke patients treated with IV-TPA within 4.5 hours of symptom-onset during 2007-2010 were prospectively entered in the thrombolyzed registry maintained at our tertiary care center. Data were collected for demographic characteristics, vascular risk factors, stroke subtypes and blood pressure levels before IV-TPA bolus. National Institute of Health Stroke Scale (NIHSS) scores were obtained before IV-TPA bolus and at 2-hours. ENI-2 was defined as a reduction in NIHSS score by more than 10-points from baseline score or an absolute score of 4-points or less at 2-hours after IV-TPA bolus. Functional outcomes at 3-months were determined by modified Rankin scale (mRS). Data were analyzed by SPSS 19.0.

Results: Of the 2238 AIS patients admitted during the study period, 240 (11%) received IV-TPA within 4.5-hours of symptom-onset. Median age was 65yrs (range 19-92), 63% males, median NIHSS 17points (range 3-35) and median onset-to-treatment time 149 minutes. Overall, 122 (50.8%) patients achieved favorable functional outcome (mRS 0-1) at 3-months. Factors associated with favorable outcome at 3-months on univariable analysis were younger age, female gender, presence of atrial fibrillation, baseline NIHSS, onset-to-treatment time (OTT) and ENI-2. However, multivariable analysis demonstrated NIHSS at onset (OR per 1-point increase 0.907, 95%CI 0.848-0.969) and ENI-2 (OR 4.926 95%CI 1.66-15.15) as independent predictors of favorable outcome at 3-months.

Conclusion: Early Neurological improvement at 2-hours after IV-TPA bolus is a strong predictor of the functional outcome at 3-months in acute ischemic stroke patients.

Current Status of Intravenous Thrombolysis for Acute Ischemic Stroke in Asia

Background

Data regarding thrombolysis for acute ischemic stroke in Asia are scarce and only a small percentage of patients are thrombolysed. The dose of intravenous tissue plasminogen activator (IV-tPA) in Asia remains controversial. Case-controlled observation studies in Asia included only Japanese patients and suggested the clinical efficacy and safety of low-dose IV-tPA (0·6 mg/kg body weight; max 60 mg) comparable to standard dose (0·9 mg/kg body weight; max. 90 mg). Reduced treatment cost, lower symptomatic intracerebral hemorrhage risk and comparable efficacy encouraged many Asian centers to adopt low-dose or even variable-dose IV-tPA regimens. We evaluated various Asian thrombolysis studies and compared with SITS-MOST registry and NINDS trial.

Methods

We included the published studies on acute ischemic stroke thrombolysis in Asia. Unadjusted relative risks and 95% Confidence intervals were calculated for each study. Pooled estimates from random effects models were used because the tests for heterogeneity were significant.

Results

We found only 18 publications regarding acute ischemic stroke thrombolysis in Asia that included total of 9300 patients. Owing to ethnic differences, stroke severity, small number of cases in individual reports, outcome measures and tPA dose regimes, it is difficult to compare these studies. Functional outcomes were almost similar (to Japanese studies) when lower-dose IV-tPA was used in non-Japanese populations across Asia. Interestingly, with standard dose IV-tPA, considerably better functional outcomes were observed, without increasing symptomatic intracerebral hemorrhage rates.

Conclusions

Variable dose regimens of IV-tPA are used across Asia without any reliable or established evidence. Establishing a uniform IV-tPA regimen is essential since the rapid improvements in health-care facilities and public awareness are expected to increase the rates of thrombolysis in Asia.

Brain attack: needing resuscitation

The brain is extremely susceptible to focal ischaemia. Following vascular occlusion, a core of severely damaged brain tissue develops, surrounded by an ischaemic penumbra. This potentially-salvageable penumbra may be estimated by advanced neuroimaging techniques, particularly by diffusion-perfusion mismatch. Clinical trials have demonstrated the efficacy of intravenous thrombolysis within three hours of onset of ischaemic stroke in reducing short-term disability. Recanalisation is enhanced by intra-arterial thrombolysis, sonothrombolysis and clot-retrieval devices. Occasionally, reperfusion injury may lead to clinical deterioration. The search continues for effective neuroprotectants. Brain perfusion needs to be maintained through blood and intracranial pressure management. Hemicraniectomy for 'malignant' cerebral oedema reduces death and disability. Elevated glucose should be controlled and hypoxia alleviated. Public education of symptoms and the need for immediate presentation to a medical facility is needed. Stroke unit care reduces death and disability with little increase in cost. Current evidence supports urgent efforts to resuscitate the brain after stroke.

Chronic brainstem ischemia in subclavian steal syndrome

Subclavian steal syndrome is usually an incidental finding and rarely causes vertebrobasilar ischemia. We present a 58-year-old man who, over six months, experienced progressive slowing in both talking and walking. Cervical duplex sonography revealed severe stenosis of the right subclavian artery; fixed retrograde flow was noted in the right vertebral artery on transcranial Doppler. The hyperemia-ischemia cuff test resulted in considerable reduction in flow velocities in both posterior cerebral arteries. We attributed his slowness to chronic vertebrobasilar ischemia and surgical revascularization was performed. His symptoms subsided immediately after surgery. The improved perfusion in the posterior circulation was demonstrated on technetium-99 hexamethylpropyleneamine oxime single photon-emission CT. Early diagnosis and prompt treatment resulted in an improved quality of life.

Reversed flow in the basilar artery in acute vertebrobasilar ischemia

Acute vertebrobasilar ischemia is a potentially sinister pathology with high mortality and poor functional outcome in survivors. We report the findings of multi-modal assessment (MRI and cerebrovascular ultrasonography) of cerebral hemodynamics in a patient who suffered from acute brainstem infarction with National Institute of Health Stroke Scale (NIHSS) score of 16 points. Our patient demonstrated reversal of blood flow in the basilar artery on the second day of his stroke and this was associated with significant and rapid clinical recovery over the following 2 days (NIHSS score dropped to 4 points). He had recovered completely when seen in the outpatient clinic 3 months later.

Alternatives to transtemporal approach of transcranial Doppler for the detection of right-to-left cardiac shunt

BACKGROUND

Transcranial Doppler (TCD) is reliable and reproducible for the diagnosis of right-to-left cardiac shunts (RLS).

METHODS

Various factors limiting the performance and diagnostic methods of RLS by TCD are discussed.

RESULTS

In patients with insufficient temporal acoustic windows, TCD may still be reliably used to monitor the microembolic signals at various alternative sites. Diagnostic yield of TCD may be further improved and better quantitative assessment of the 'functional potential' of the RLS by optimizing the preparation of the 'air-saline-blood' contrast-mixture, injecting the mixture in controlled body positions and using power M-mode TCD.

CONCLUSIONS

TCD may be used reliably for the detection as well as the quantification of RLS even in patients with insufficient temporal acoustic windows.

Isolated cortical vein thrombosis - the cord sign

Isolated cortical vein thrombosis is an uncommon condition and often difficult to diagnose, both clinically and radiologically. We report a case of a 38 years old man who presented with headache of new onset and clinical examination was unremarkable. The unenhanced brain CT did not reveal any abnormality. In view of unrelenting headache and partial seizures, we performed magnetic resonance imaging (with axial T1, T2 and gradient echo sequences, coronal FLAIR, diffusion weighted imaging as well as Gadolinium contrast-enhanced images) and magnetic resonance venography of the brain that revealed an isolated parietal cortical vein thrombosis with the rarely reported 'cord sign'. We report the clinical and radiological findings in our patient with isolated parietal cortical vein thrombosis.

Role of Multimodal Evaluation of Cerebral Hemodynamics in Selecting Patients with Symptomatic Carotid or Middle Cerebral Artery Steno-occlusive Disease for Revascularization

BACKGROUND

The circle of Willis provides collateral pathways to perfuse the affected vascular territories in patients with severe stenoocclusive disease of major arteries. The collateral perfusion may become insufficient in certain physiological circumstances due to failed vasodilatory reserve and intracranial steal phenomenon, so-called 'Reversed-Robinhood syndrome'. We evaluated cerebral hemodynamics and vasodilatory reserve in patients with symptomatic distal internal carotid (ICA) or middle cerebral artery (MCA) severe steno-occlusive disease.

METHODS

Diagnostic transcranial Doppler (TCD) and TCD-monitoring with voluntary breath-holding according to a standard scanning protocol were performed in patients with severe ICA or MCA steno-occlusive disease. The steal phenomenon was detected as transient, spontaneous, or vasodilatory stimuli-induced velocity reductions in affected arteries at the time of velocity increase in normal vessels. Patients with exhausted vasomotor reactivity and intracranial steal phenomenon during breath-holding were further evaluated by (99)technetium(m)-hexamethyl propylene amine oxime single photon emission computed tomography (HMPAO-SPECT) with acetazolamide challenge.

RESULTS

Sixteen patients (age 27-74 years, 11 men) fulfilled our TCD criteria for exhausted vasomotor reactivity and intracranial steal phenomenon during the standard vasomotor testing by breath holding. Acetazolamide-challenged HMPAO-SPECT demonstrated significant hypoperfusion in 12 patients in affected arterial territories, suggestive of failed vasodilatory reserve. A breath-holding index of ≤0.3 on TCD was associated with an abnormal HMPAO-SPECT with acetazolamide challenge. TCD findings of a breath holding index of ≤0.3 and intracranial steal during the procedure were determinants of a significant abnormality on HMPAO-SPECT with acetazolamide challenge.

CONCLUSION

Multimodal evaluation of cerebral hemodynamics in symptomatic patients with severe steno-occlusive disease of the ICA or MCA is helpful in the identification and quantification of failed vasodilatory reserve. This approach may be useful in selecting patients for possible revascularization procedures.

Skin wrinkling for diagnosing small fibre neuropathy: comparison with epidermal nerve density and sympathetic skin response

OBJECTIVE

To compare simple tests of small nerve fibre function with intraepidermal nerve fibre density (IENFD) in the evaluation of small fibre neuropathy (SFN).

METHODS

Patients with idiopathic SFN of the hands were prospectively studied. Evaluation involved clinical examination, nerve conduction studies, sympathetic skin response (SSR) and skin wrinkling stimulated by water and EMLA (eutectic mixture of local anaesthetics).

RESULTS

Of 21 patients, 16 (76%) had low IENFD, 15 (71%) impaired water-induced wrinkling, 14 (67%) impaired EMLA-induced wrinkling, and nine (43%) abnormal SSR.

CONCLUSIONS

Stimulated skin wrinkling was nearly as sensitive as IENFD in diagnosing SFN, whereas SSR was of less use. Stimulated skin wrinkling is a useful supportive test when IENFD or other tests of small nerve fibre function are not available.

Prevalence of patent foramen ovale in patients with migraine

Cerebral embolization through a PFO is considered to be a possible cause of migraine attack, therefore the size of the PFO and its 'functional potential' should play an important etiological role in migraine. However, this relationship remains complex due to various methodological issues. We have highlighted some of the important issues related to the diagnostic methodology for PFO and the interpretation of the results. Mere detection of the presence of PFO in patients with migraine may not delineate their true relationship for a better understanding and planning a definitive treatment. There is an urgent need for standardizing the diagnostic methods as well as the criteria for the grading the 'functional status' of PFO.