The Hunter-8 Scale Prehospital Triage Workflow for Identification of Large Vessel Occlusion and Brain Haemorrhage.

OBJECTIVE: The Hunter-8 prehospital stroke scale predicts large vessel occlusion in hyperacute ischemic stroke patients (LVO) at hospital admission. We wished to test its performance in the hands of paramedics as part of a prehospital triage algorithm. We aimed to determine (a) the proportion of patients identified by the Hunter-8 algorithm, receiving reperfusion therapies, (b) whether a call to stroke team improved this, and (c) performance for LVO detection using an expanded LVO definition. METHODS: A prehospital workflow combining pre-morbid functional status, time from symptom onset, and the Hunter-8 scale was implemented from July 2019. A telephone call to the stroke team was prompted for potential treatment candidates. Classic LVO was defined as a proximal middle cerebral artery (MCA-M1), terminal internal carotid artery, or tandem occlusion. Extended LVO added proximal MCA-M2 and basilar occlusions. RESULTS: From July 2019 to April 2021, there were 363 Hunter-8 activations, 320 analyzed: 181 (56.6%) had confirmed ischemic strokes, 13 (4.1%) transient ischemic attack, 91 (28.5%) stroke mimics, and 35 (10.9%) intracranial hemorrhage. Fifty-two patients (16.3%) received reperfusion therapies, 35 with Hunter-8 ≥ 8. The stroke doctor changed the final destination for 76 patients (23.7%), and five received reperfusion therapies. The AUCs for classic and extended LVO were 0.73 (95% CI 0.66-0.79) and 0.72 (95% CI 0.65-0.77), respectively. CONCLUSION: The Hunter-8 workflow resulted in 28.7% of confirmed ischemic stroke patients receiving reperfusion therapies, with no secondary transfers to the comprehensive stroke center. The role of communication with stroke team needs to be further explored.

Pulse pressure variability is associated with unfavorable outcomes in acute ischaemic stroke patients treated with intravenous thrombolysis.

BACKGROUND AND PURPOSE: Blood pressure (BP) variability has been associated with worse neurological outcomes in acute ischaemic stroke (AIS) patients receiving treatment with intravenous thrombolysis (IVT). However, no study to date has investigated whether pulse pressure (PP) variability may be a superior indicator of the total cardiovascular risk, as measured by clinical outcomes. METHODS: Pulse pressure variability was calculated from 24-h PP measurements following tissue plasminogen activator bolus in AIS patients enrolled in the Combined Lysis of Thrombus using Ultrasound and Systemic Tissue Plasminogen Activator for Emergent Revascularization (CLOTBUST-ER) trial. The outcomes of interest were the pre-specified efficacy and safety end-points of CLOTBUST-ER. All associations were adjusted for potential confounders in multivariable regression models. RESULTS: Data from 674 participants was analyzed. PP variability was identified as the BP parameter with the most parsimonious fit in multivariable models of all outcomes, and was independently associated (P < 0.001) with lower likelihood of both 24-h neurological improvement and 90-day independent functional outcome. PP variability was also independently related to increased odds of any intracranial bleeding (P = 0.011) and 90-day mortality (P < 0.001). Every 5-mmHg increase in the 24-h PP variability was independently associated with a 36% decrease in the likelihood of 90-day independent functional outcome (adjusted odds ratio 0.64, 95% confidence interval 0.52-0.80) and a 60% increase in the odds of 90-day mortality (adjusted odds ratio 1.60, 95% confidence interval 1.23-2.07). PP variability was not associated with symptomatic intracranial bleeding at either 24 or 36 h after IVT administration. CONCLUSIONS: Increased PP variability appears to be independently associated with adverse short-term and long-term functional outcomes of AIS patients treated with IVT.

Usefulness of Video Review of Possible Concussions in National Youth Rugby League.

A new concussion interchange rule (CIR) was introduced in 2014 for the National Rugby League and National Youth Competition (NYC). The CIR allows a player suspected of having sustained a concussion to be removed from play and assessed without an interchange being tallied against the player's team. Participants included all NYC players who used the CIR during the 2014 season. 2 raters completed video analysis of 131 (of a total of 156 reported) uses of the CIR, describing injury characteristics, situational factors, and concussion signs. The incidence rate was 44.9 (95% CI: 38.5-52.3) uses of the CIR per 1 000 NYC player match hours, or approximately one CIR use every 1.3 games. Apparent loss of consciousness/unresponsiveness was observed in 13% of cases, clutching the head in 65%, unsteadiness of gait in 60%, and a vacant stare in 23%. Most incidences occurred from a hit-up (82%). There appeared to be some instances of video evidence of injury but the athlete was cleared to return to play in the same game. Video review appears to be a useful adjunct for identifying players suffering possible concussion. Further research is required on the usefulness of video review for identifying signs of concussive injury.

A Video Analysis of Use of the New 'Concussion Interchange Rule' in the National Rugby League.

The National Rugby League (NRL) in Australia introduced a new 'concussion interchange rule' (CIR) in 2014, whereby a player suspected of having sustained a concussion can be removed from play, and assessed, without an interchange being tallied against the player's team. We conducted a video analysis, describing player and injury characteristics, situational factors, concussion signs, and return to play for each "CIR" event for the 2014 season. There were 167 reported uses of the CIR. Apparent loss of consciousness/unresponsiveness was observed in 32% of cases, loss of muscle tone in 54%, clutching the head in 70%, unsteadiness of gait in 66%, and a vacant stare in 66%. More than half of the players who were removed under the CIR returned to play later in the same match (57%). Most incidences occurred from a hit up (62%) and occurred during a tackle where the initial contact was with the upper body (80%). The new concussion interchange rule has been used frequently during the first season of its implementation. In many cases, there appeared to be video evidence of injury but the athlete was cleared to return to play. More research is needed on the usefulness of video review for identifying signs of concussive injury.

Perfusion computed tomography thresholds defining ischemic penumbra and infarct core: studies in a rat stroke model.

BACKGROUND: Perfusion computed tomography is becoming more widely used as a clinical imaging tool to predict potentially salvageable tissue (ischemic penumbra) after ischemic stroke and guide reperfusion therapies. AIMS: The study aims to determine whether there are important changes in perfusion computed tomography thresholds defining ischemic penumbra and infarct core over time following stroke. METHODS: Permanent middle cerebral artery occlusion was performed in adult outbred Wistar rats (n = 6) and serial perfusion computed tomography scans were taken every 30 mins for 2 h. To define infarction thresholds at 1 h and 2 h post-stroke, separate groups of rats underwent 1 h (n = 6) and 2 h (n = 6) of middle cerebral artery occlusion followed by reperfusion. Infarct volumes were defined by histology at 24 h. Co-registration with perfusion computed tomography maps (cerebral blood flow, cerebral blood volume, and mean transit time) permitted pixel-based analysis of thresholds defining infarction, using receiver operating characteristic curves. RESULTS: Relative cerebral blood flow was the perfusion computed tomography parameter that most accurately predicted penumbra (area under the curve = 0.698) and also infarct core (area under the curve = 0.750). A relative cerebral blood flow threshold of < 75% of mean contralateral cerebral blood flow most accurately predicted penumbral tissue at 0.5 h (area under the curve = 0.660), 1 h (area under the curve = 0.659), 1.5 h (area under the curve = 0.636), and 2 h (area under the curve = 0.664) after stroke onset. A relative cerebral blood flow threshold of < 55% of mean contralateral most accurately predicted infarct core at 1 h (area under the curve = 0.765) and at 2 h (area under the curve = 0.689) after middle cerebral artery occlusion. CONCLUSIONS: The data provide perfusion computed tomography defined relative cerebral blood flow thresholds for infarct core and ischemic penumbra within the first two hours after experimental stroke in rats. These thresholds were shown to be stable to define the volume of infarct core and penumbra within this time window.

Short-duration hypothermia after ischemic stroke prevents delayed intracranial pressure rise.

BACKGROUND: Intracranial pressure elevation, peaking three to seven post-stroke is well recognized following large strokes. Data following small-moderate stroke are limited. Therapeutic hypothermia improves outcome after cardiac arrest, is strongly neuroprotective in experimental stroke, and is under clinical trial in stroke. Hypothermia lowers elevated intracranial pressure; however, rebound intracranial pressure elevation and neurological deterioration may occur during rewarming. HYPOTHESES: (1) Intracranial pressure increases 24 h after moderate and small strokes. (2) Short-duration hypothermia-rewarming, instituted before intracranial pressure elevation, prevents this 24 h intracranial pressure elevation. METHODS: Long-Evans rats with two hour middle cerebral artery occlusion or outbred Wistar rats with three hour middle cerebral artery occlusion had intracranial pressure measured at baseline and 24 h. Wistars were randomized to 2·5 h hypothermia (32·5°C) or normothermia, commencing 1 h after stroke. RESULTS: In Long-Evans rats (n = 5), intracranial pressure increased from 10·9 ± 4·6 mmHg at baseline to 32·4 ± 11·4 mmHg at 24 h, infarct volume was 84·3 ± 15·9 mm(3) . In normothermic Wistars (n = 10), intracranial pressure increased from 6·7 ± 2·3 mmHg to 31·6 ± 9·3 mmHg, infarct volume was 31·3 ± 18·4 mm(3) . In hypothermia-treated Wistars (n = 10), 24 h intracranial pressure did not increase (7·0 ± 2·8 mmHg, P < 0·001 vs. normothermia), and infarct volume was smaller (15·4 ± 11·8 mm(3) , P < 0·05). CONCLUSIONS: We saw major intracranial pressure elevation 24 h after stroke in two rat strains, even after small strokes. Short-duration hypothermia prevented the intracranial pressure rise, an effect sustained for at least 18 h after rewarming. The findings have potentially important implications for design of future clinical trials.

Metropolitan-rural divide for stroke outcomes: do stroke units make a difference?

BACKGROUND: Stroke care across Australian hospitals is variable. The impact on health outcomes, in particular levels of disability for patients in rural areas, is unclear. The aim of this study was to determine whether geographic location and access to stroke units are associated with differences in health outcomes in patients with acute stroke. METHODS: Retrospective cohort study of consecutive eligible admissions from 32 hospitals (12 rural) in New South Wales between 2003 and 2007. Health status measured at discharge included level of independence (modified Rankin score: mRS) and frequency of severe complications during hospitalization. Multivariable analyses included adjustment for patient casemix and clustering. RESULTS: Among 2254 eligible patients, 55% were treated in metropolitan hospitals. Stroke unit treatment varied significantly (rural 3%; metropolitan 77%). Age, gender and stroke type did not differ by location (mean age 74, 50% female). After adjusting for age, gender, ethnicity, important risk factors and validated stroke prognostic variables, patients treated in rural hospitals had a greater odds of dying during hospitalization compared with those treated in metropolitan hospitals (adjusted odds ratio (aOR) 1.46, 95% confidence interval (CI) 1.03-2.05). There were no differences in mortality or frequency of severe complications between patients treated in rural and metropolitan hospitals when we adjusted for access to stroke units (aOR 1.00, 95% CI 0.62-1.61). Nevertheless, patients treated in rural hospitals were more dependent (mRS 3-5) at discharge (aOR 1.82, 95% CI 1.23-2.70) despite adjusting for stroke unit status. CONCLUSION: Patients with stroke treated in rural hospitals have poorer health outcomes, especially if not managed in stroke units.

Ischemic diffusion lesion reversal is uncommon and rarely alters perfusion-diffusion mismatch.

OBJECTIVE: The use of diffusion-weighted imaging (DWI) to define irreversibly damaged infarct core is challenged by data suggesting potential partial reversal of DWI abnormalities. However, previous studies have not considered infarct involution. We investigated the prevalence of DWI lesion reversal in the EPITHET Trial. METHODS: EPITHET randomized patients 3-6 hours from onset of acute ischemic stroke to tissue plasminogen activator (tPA) or placebo. Pretreatment DWI and day 90 T2-weighted images were coregistered. Apparent reversal of the acute ischemic lesion was defined as DWI lesion not incorporated into the final infarct. Voxels of CSF at follow-up were subtracted from regions of apparent DWI lesion reversal to adjust for infarct atrophy. All cases were visually cross-checked to exclude volume loss and coregistration inaccuracies. RESULTS: In 60 patients, apparent reversal involved a median 46% of the baseline DWI lesion (median volume 4.9 mL, interquartile range 2.6-9.5 mL) and was associated with less severe baseline hypoperfusion (p < 0.001). Apparent reversal was increased by reperfusion, regardless of the severity of baseline hypoperfusion (p = 0.02). However, the median volume of apparent reversal was reduced by 45% when CSF voxels were subtracted (2.7 mL, interquartile range 1.6-6.2 mL, p < 0.001). Perfusion-diffusion mismatch classification only rarely altered after adjusting the baseline DWI volume for apparent reversal. Visual comparison of acute DWI to subacute DWI or day 90 T2 identified minor regions of true DWI lesion reversal in only 6 of 93 patients. CONCLUSIONS: True DWI lesion reversal is uncommon in ischemic stroke patients. The volume of apparent lesion reversal is small and would rarely affect treatment decisions based on perfusion-diffusion mismatch.

Acute stroke and transient ischaemic attack management--time to act fast.

Stroke is Australia's second single greatest killer with 53 000 new events each year at a rate of 1 every 10 min. Stroke services should be organized to enable people to access proven therapies, such as stroke unit care and thrombolysis, to reduce the impact of stroke. Timely, efficient and coordinated care from ambulance services, emergency services and stroke services will maximize recovery and prevent costly complications and subsequent strokes. Efficient management of patients with transient ischaemic attack can produce significant reductions in subsequent stroke events and risk stratification using the ABCD2 tool can aid management decisions. Evidence for acute stroke care continues to evolve and it is crucial that health professionals are aware of, and implement, best practice clinical guidelines for stroke care.

Acute ischemic stroke: imaging-guided tenecteplase treatment in an extended time window.

BACKGROUND: Tenecteplase is a modified tissue plasminogen activator with a longer half-life and higher fibrin specificity than alteplase. METHODS: We conducted a prospective, nonrandomized, pilot study of 0.1 mg/kg IV tenecteplase given 3 to 6 hours after ischemic stroke onset. For a control group, we used patients contemporaneously treated with sub-3-hour 0.9 mg/kg IV alteplase following standard selection criteria. All patients underwent pretreatment and 24-hour perfusion/angiographic imaging with CT or MRI. Eligibility criteria for tenecteplase (but not alteplase) treatment included a perfusion lesion at least 20% greater than the infarct core, with an associated vessel occlusion. Primary outcomes, assessed blind to treatment group, were reperfusion (reduction in baseline-24-hour mean transit time lesion) and major vessel recanalization. RESULTS: Fifteen patients received tenecteplase, and 35 patients received alteplase. The tenecteplase group had greater reperfusion (mean 74% vs 44% in the alteplase group, p = 0.01) and major vessel recanalization (10/15 tenecteplase vs 7/29 alteplase, p = 0.01). Despite later time to treatment, more tenecteplase patients (10/15 vs 7/35 alteplase, p = 0.001) had major neurologic improvement at 24 hours (NIH Stroke Scale reduction > or = 8). Four of the alteplase patients and none of the tenecteplase patients had parenchymal hematoma at 24 hours. CONCLUSIONS: Tenecteplase 0.1 mg/kg, using advanced imaging guidance in an extended time window, may have significant biologic efficacy in acute ischemic stroke. The imaging selection differences between the tenecteplase and alteplase groups prevent a conclusive efficacy comparison. Nonetheless, these results lend support for randomized trials comparing tenecteplase with alteplase, preferably incorporating penumbral/angiographic imaging selection.

Improvements in the quality of care and health outcomes with new stroke care units following implementation of a clinician-led, health system redesign programme in New South Wales, Australia.

BACKGROUND AND OBJECTIVES: Provision of evidence-based hospital stroke care is limited worldwide. In Australia, about a fifth of public hospitals provide stroke care units (SCUs). In 2001, the New South Wales (NSW) state government funded a clinician-led, health system redesign programme that included inpatient stroke services. Our objective was to determine the effects of this initiative for improving: (i) access to SCUs and care quality and (ii) health outcomes. DESIGN, SETTING AND PARTICIPANTS: Preintervention-postintervention design (12 months prior and a minimum 6-12 months following SCU implementation). Retrospective, public hospital audit of 50 consecutive medical records per time period of stroke admissions (using International Classification of Diseases (ICD)-10 codes). Combined analyses for 15 hospitals presented. OUTCOMES: Process of care indicators and patient independence (proportional odds modelling using modified Rankin scale). RESULTS: Pre-programme cases (n = 703) (mean (SD) age 74 (14) years; female: 51%) and post-programme cases (n = 884) (mean age 74 (14) years; female: 49%) were comparable. Significant post-programme improvements for most process indicators were found, such as more brain imaging within 24 hours. Post-programme, access to SCUs increased 22-fold (95% CI 16.8 to 28.3). Improvement in inpatient independence at post-programme discharge was significant compared with pre-programme outcomes (proportional odds ratio 0.73, 95% CI 0.57 to 0.94; p = 0.013) when adjusted for patient clustering and case mix. CONCLUSIONS: This distinctive SCU initiative was shown as effective for improving clinical practice and significantly reducing disability following stroke.

Identification of the penumbra and infarct core on hyperacute noncontrast and perfusion CT.

OBJECTIVES: To correlate the two types of early ischemic change on noncontrast CT (NCCT) (parenchymal hypoattenuation [PH] and isolated focal swelling [IFS]) with concurrent assessment of cerebral perfusion and to compare their rates of progression to infarction. METHODS: We assessed cortical regions on NCCT for early ischemic change. Quantitative perfusion values were calculated for cortical regions from acute CT perfusion (CTP) maps of cerebral blood volume (CBV), blood flow (CBF), and mean transit time (MTT). Reperfusion and presence of infarction were determined from follow-up MRI. RESULTS: We studied 40 patients with sub-6 hour anterior circulation ischemic stroke; 19 received IV recombinant tissue plasminogen activator. Of the 202 regions acutely hypoperfused on CTP, 123 were normal on NCCT, 58 had PH, and 21 had IFS. Acute CBV was low in PH regions, and elevated in IFS regions. Acute CBF was reduced in IFS regions, but more so in PH regions. Progression to infarction occurred in virtually all PH regions, but IFS regions had much lower rates of infarction with major reperfusion. Acute CBV in hypoperfused normal NCCT regions ranged from reduced to elevated, with substantially differing risk of infarction. CONCLUSIONS: Isolated focal swelling identifies penumbral tissue and parenchymal hypoattenuation identifies infarct core. Although this has prognostic implications when assessing patient suitability for thrombolytic therapy, the majority of acutely hypoperfused regions appear normal on noncontrast CT. Perfusion CT can stratify the level of risk of subsequent infarction for normal-appearing regions on noncontrast CT.

Timing of clinically significant microembolism after carotid endarterectomy.

PURPOSE: Post-operatively detected transcranial Doppler (TCD) embolic signals (ES) are associated with an increased risk of carotid endarterectomy (CEA) stroke/TIA. The aims here were to quantify this risk and determine the most efficient monitoring protocol. METHODS: Sequential patients undergoing CEA (enrolled in a randomised, blinded, placebo-controlled trial of peri-operative dextran therapy) had 30-min TCD monitoring in the first post-operative hour. 30-min monitoring was also performed 2-3, 4-6 and 24-36 h post-operatively. First post-operative hour ES counts were correlated with peri-operative ipsilateral carotid stroke/TIA to determine the size of a clinically significant ES load and the magnitude of the associated risk. The exact Cochran-Armitage test for trend in proportions was used to determine when a clinically significant ES load was first detected. RESULTS: 141 patients (mean age 69.3 years, 72% male) were monitored during the first post-operative hour. An ES count >10 per recording was identified as the best overall predictor of ipsilateral stroke/TIA (sensitivity 72%, specificity 89%). 3/119 (2.5%) patients with 0-10 ES had ipsilateral carotid events compared to 8/22 (36.4%) patients with 11-115 ES (OR = 22.1, 95% CI 4.5, 138.4, p < 0.0001). 13/18 (72%) of subjects with >10 ES were identified in the first post-operative hour with no significant increase in the number of new cases over the subsequent 24-36 post-operative h (p = 0.354). CONCLUSION: Patients with clinically significant post-operative microembolism had an approximately 15 times higher risk of ipsilateral stroke/TIA and most were identified during a 30-min study in the first post-operative hour.

Access to stroke care units in Australian public hospitals: facts and temporal progress.

BACKGROUND: There is level I evidence that management of stroke patients in stroke units (SU) improves outcomes (death and institutionalization) by approximately 20%. In Australia, there is uncertainty as to the proportion of incident cases that have access to SU. Recent national and State-based policy initiatives to increase access to SU have been taken. However, objective evidence related to SU implementation progress is lacking. The aims of the study were (i) to determine the number of SU in Australian acute public hospitals in 2004, (ii) to describe hospitals according to national SU policy criteria and (iii) to compare results to the 1999 survey to track progress. METHODS: The method used in the study was a cross-sectional, postal survey technique. The participants were clinical representatives considered appropriate to describe stroke care within survey hospitals. RESULTS: The outcome of the study was presence of a SU according to an accepted definition. Response rate was 261/301 (87%). Sixty-one sites (23%) had either a SU and/or a dedicated stroke team. Fifty sites claimed to have a SU (19%). New South Wales with 23 had the most number of SU. Based on policy criteria, up to 64 sites could have a SU. In 1999, there were 35 public hospitals with a SU. CONCLUSION: Access to SU in Australian public hospitals remains low compared with other countries (Sweden, 70%). Implementation strategies supported by appropriate health policy to improve access are needed.

Lacunar stroke: transoesophageal echocardiographic factors influencing long-term prognosis.

OBJECTIVE: Since little is known concerning factors which may influence long-term prognosis of patients presenting with lacunar stroke, we conducted a longitudinal study of this stroke subtype. Variables likely to affect outcome were assessed at baseline, including those from transoesophageal echocardiographic studies. METHODS: Consecutive patients presenting with first-ever lacunar stroke underwent diagnostic workup that included brain CT or MRI, carotid duplex, and transthoracic and transoesophageal echocardiography. An assessment of patients was planned at entry (baseline), and thereafter every 12 months (clinic visit or telephone call), drop-out, or endpoint. The primary endpoint was nonfatal or fatal stroke. Secondary endpoint was death due to any cause. RESULTS: Among 60 consecutive lacunar patients with the mean follow-up period of 3.9 years, 12 patients (20%) had stroke recurrence. The mean annual rate for stroke was 5.2%, and for death 2.8%. For multivariate Cox proportional hazards analysis, the following three variables with the values of p < 0.1 after univariate testing were chosen: age (p = 0.095); aortic atheroma (p = 0.066); and any source of embolism from heart (p = 0.007). Any source of embolism from heart was the only factor which significantly enhanced the risk of stroke recurrence (p = 0.015). Using Kaplan-Meier life table analysis, the curves of percent free of recurrent stroke were significantly different (log rank test p = 0.002). CONCLUSIONS: Until the mechanism of lacunar stroke is better understood, it is reasonable to suggest that its investigation and prevention should be directed at all potential causes of future strokes including cardioembolism.

Dextran reduces embolic signals after carotid endarterectomy.

One hundred fifty patients undergoing carotid endarterectomy were randomly assigned to receive intravenous 10% dextran 40 or placebo. Transcranial Doppler monitoring of the ipsilateral middle cerebral artery 0 to 1 hour postoperatively detected embolic signals in 57% of placebo and 42% of dextran patients, with overall embolic signal counts 46% less for dextran (p = 0.052). Two to 3 hours postoperatively, embolic signals were present in 45% of placebo and 27% of dextran patients, with embolic signal counts 64% less for dextran (p = 0.040). We conclude that dextran reduces embolic signals within 3 hours of CEA.

Risk factors for lacunar stroke: a case-control transesophageal echocardiographic study.

To reassess the independent risk factors for lacunar stroke and to clarify the role of potential embolic sources, we conducted a case-control study using transesophageal echocardiography and duplex ultrasonography. Among 62 consecutive patients with their first lacunar stroke and 202 normal controls, we found that hypertension (p < 0.001), smoking (p = 0.001), and aortic arch atheroma (p = 0.006) were independently associated with an increased risk of lacunar stroke. Whether proximal aortic arch atheroma is mechanistically associated with lacunar stroke or merely coexistent is uncertain.

White matter medullary infarcts: acute subcortical infarction in the centrum ovale.

Acute infarction confined to the territory of the white matter medullary arteries is a poorly characterised acute stroke subtype. 22 patients with infarction confined to this vascular territory on CT and/or MRI were identified from a series of 1,800 consecutive admissions to our stroke unit (1.2%) between August 1993 and March 1997. 19 patients had small infarcts (< 1.5 cm maximum diameter) and 3 large infarcts (> 1.5 cm). Small infarcts were associated with a history of smoking (69%), hypertension (58%), and hyperlipidaemia (37%), and less frequently with atrial fibrillation (21%). Significant (>50%) ipsilateral carotid stenosis (16%) was a less frequent finding in this group. Patients most commonly presented with weakness and/or sensory disturbance affecting mainly the upper limbs, but dysarthria, dysphasia, and ataxia were also seen. Large infarcts were infrequent in our series, but did not differ significantly from small infarcts with respect to clinical presentation or risk factor profiles (p > 0.05 for all comparisons). The majority of symptomatic patients with white matter medullary infarcts are associated with small (< 1.5 cm diameter) lesions and a risk factor profile consistent with small vessel disease. More data are required to elucidate the mechanism of larger (> 1.5 cm) infarcts. Because of the potential overlap between white matter medullary infarcts and internal watershed infarcts, suggested criteria for each are presented.

Extensive hemispheric cerebral infarction.

BACKGROUND AND PURPOSE: Patients with extensive hemispheric cerebral infarction have a high incidence of mortality and serious morbidity. Because of their poor prognosis, they warrant attention; however, in acute stroke therapy trials they do not appear to benefit from treatment. We sought to determine the clinical features, pathophysiological mechanisms, and outcome in a series of cases with radiologically defined extensive hemispheric infarction. METHODS: Cases of extensive hemispheric infarction were ascretained retrospectively from stroke admissions during a 5-year period. Extensive hemispheric infarction was defined radiologically as infarction involving greater than 75% of the middle cerebral artery territory, with or without involvement of the adjacent anterior or posterior cerebral artery territories. Clinical, risk factor, and stroke mechanism data were compared with that of a control group of ischemic stroke patients admitted during the same period. RESULTS: Extensive hemispheric infarction occurred in 53 of 1,440 cases of ischemic stroke (3.7%). Infarction involved the middle cerebral artery territory alone in 79% of cases, and the adjacent anterior or posterior cerebral artery territories as well as 21% of cases. A cardioembolic mechanism was likely in 58% of cases; 42% had atrial fibrillation. When compared with the control group, a cardioembolic mechanism was the only feature more frequently associated with extensive hemispheric infarction. The overall in-hospital mortality rate was 52%; 84% of those discharged from hospital required nursing home care because of severe disability. CONCLUSION: Although uncommon, extensive hemispheric infarction is an important stroke subtype with dramatic and easily recognizable presenting clinical features, frequent cardio-embolic mechanism, an extremely poor outcome, and failure to benefit from most experimental acute stroke therapies.

Transcranial Doppler microembolus detection in the identification of patients at high risk of perioperative stroke.

OBJECTIVES: Perioperative ischaemic stroke is the leading cause of morbidity and mortality associated with carotid endarterectomy (CEA). The aim was to test the hypotheses that the detection of microembolic ultrasonic signals (MES) with transcranial Doppler ultrasound (TCD) during and after the operation may be of value in identifying patients at increased perioperative stroke risk. DESIGN: Open prospective case series. PATIENTS AND METHODS: Eighty-one consecutive patients undergoing CEA with TCD monitoring. Preoperative, intraoperative and interval postoperative TCD monitoring of the middle cerebral artery (MCA) ipsilateral to the operated carotid artery. On-line pre- and intraoperative MES counting and blinded off-line analysis of postoperative MES counts. End-points were any focal neurological deficit and death at 30 days postoperatively. RESULTS: MES were detected in 94% of patients intraoperatively and 71% of cases during the first postoperative hour. MES counts ranged from 0 to 25 per operative phase (range of median counts 0-8) and from 0 to 212 per hour postoperatively (range of median counts 0-4). Eight cases (10%) developed postoperative MES counts greater than 50/h. Five of these eight cases evolved ischaemic neurological deficits in the territory of the insonated MCA, indicating a strong association between frequent postoperative microembolism and the development of early cerebral ischaemia (chi 2 = 34.2, p < 0.0001). Intraoperative MES were not associated with clinical outcome measures. CONCLUSIONS: MES counts of greater than 50/h in the early postoperative phase of carotid endarterectomy are predictive of the development of ipsilateral focal cerebral ischaemia.