Telestroke for acute ischaemic stroke: A systematic review of economic evaluations and a de novo cost-utility analysis for a middle income country

INTRODUCTION

Telemedicine can alleviate the problems faced in rural settings in providing access to specialist stroke care. The evidence of the cost-effectiveness of this model of care outside high-income countries is limited. This study aimed to conduct: (a) a systematic review of economic evaluations of telestroke and (b) a cost-utility analysis of telestroke, using China as a case study.

METHODS

We systematically searched Embase, Medline Complete and Cochrane databases. Inclusion criteria: full economic evaluations of telemedicine/telestroke networks examining the use of thrombolysis in patients with acute ischaemic stroke, published in English. A cost-utility analysis was undertaken using a Markov model incorporating a decision tree to simulate the delivery of telestroke for acute ischaemic stroke in rural China, compared to no telestroke from a societal and healthcare perspective. One-way deterministic sensitivity analyses and probabilistic sensitivity analyses were performed to test the robustness of results.

RESULTS

Of 559 publications found, eight met the eligibility criteria and were included in the systematic review (two cost-effectiveness analyses and six cost-utility analyses, all performed in high-income countries). Telestroke was a cost-saving/cost-effective intervention in five out of the eight studies. In our modelled analysis for rural China, telestroke was the dominant strategy, with estimated cost savings of Chinese yuan 4,328 (US$627) and additional 0.0925 quality-adjusted life years per patient. Sensitivity analyses confirmed the base case results.

DISCUSSION

Consistent with published economic evaluations of telestroke in other jurisdictions, telestroke represents a cost-effective solution to enhance stroke care in rural China.

Door-in-door-out times for patients with large vessel occlusion ischaemic stroke being transferred for endovascular thrombectomy: a Victorian state-wide study

Background

Time to reperfusion is an important predictor of outcome in ischaemic stroke from large vessel occlusion (LVO). For patients requiring endovascular thrombectomy (EVT), the transfer times from peripheral hospitals in metropolitan and regional Victoria, Australia to comprehensive stroke centres (CSCs) have not been studied.

Aims

To determine transfer and journey times for patients with LVO stroke being transferred for consideration of EVT.

Methods

All patients transferred for consideration of EVT to three Victorian CSCs from January 2017 to December 2018 were included. Travel times were obtained from records matched to Ambulance Victoria and the referring centre via Victorian Stroke Telemedicine or hospital medical records. Metrics of interest included door-in-door-out time (DIDO), inbound journey time and outbound journey time.

Results

Data for 455 transferred patients were obtained, of which 395 (86.8%) underwent EVT. The median DIDO was 107 min (IQR 84-145) for metropolitan sites and 132 min (IQR 108-167) for regional sites. At metropolitan referring hospitals, faster DIDO was associated with use of the same ambulance crew to transport between hospitals (75 (63-90) vs 124 (99-156) min, p<0.001) and the administration of thrombolysis prior to transfer (101 (79-133) vs 115 (91-155) min, p<0.001). At regional centres, DIDO was consistently longer when patients were transported by air (160 (127-195) vs 116 (100-144) min, p<0.001). The overall door-to-door time by air was shorter than by road for sites located more than 250 km away from the CSC.

Conclusion

Transfer times differ significantly for regional and metropolitan patients. A state-wide database to prospectively collect data on all interhospital transfers for EVT would be helpful for future study of optimal transport mode at regional sites and benchmarking of DIDO across the state.

Utstein recommendation for emergency stroke care

Background

Recent advances in treatment for stroke give new possibilities for optimizing outcomes. To deliver these prehospital care needs to become more efficient.

Aim

To develop a framework to support improved delivery of prehospital care. The recommendations are aimed at clinicians involved in prehospital and emergency health systems who will often not be stroke specialists but need clear guidance as to how to develop and deliver safe and effective care for acute stroke patients.

Methods

Building on the successful implementation program from the Global Resuscitation Alliance and the Resuscitation Academy, the Utstein methodology was used to define a generic chain of survival for Emergency Stroke Care by assembling international expertise in Stroke and Emergency Medical Services (EMS). Ten programs were identified for Acute Stroke Care to improve survival and outcomes, with recommendations for implementation of best practice.

Conclusions

Efficient prehospital systems for acute stroke will be improved through public awareness, optimized prehospital triage and timely diagnostics, and quick and equitable access to acute treatments. Documentation, use of metrics and transparency will help to build a culture of excellence and accountability.

Carotid endarterectomy: the change in practice over 11 years in a stroke centre

BACKGROUND

Recent research evidence has impacted the practice of carotid endarterectomy (CEA). We aim to characterize changes in the practice and outcome of CEA over time in a single large-volume stroke centre.

METHODS

All patients who underwent CEA from 2004 to 2014 and carotid angioplasty and stenting (CAS) from 2003 to 2008 at an Australian metropolitan tertiary stroke centre hospital were included. Clinical data were analysed to identify time trends in choice of intervention, patient selection, preoperative imaging utilization, surgical timing and outcome.

RESULTS

There were 510 CEAs performed during 2004-2014 and 95 CASs during 2003-2008. The proportion of patients undergoing CEA compared to CAS increased from 60% to 90% from 2004 to 2008 (P < 0.001). CAS patients were more likely to have cardiac co-morbidities. From 2004 to 2014, the proportion of CEA patients aged ≥80 years increased (P = 0.001) and the proportion of asymptomatic patients decreased (P = 0.003) over time. Median time from symptom onset to surgery decreased from 52 days (Q1: 25, Q3: 74) in 2004 to 8 days (Q1: 5, Q3: 37) in 2014 (P < 0.001). Use of preoperative ultrasonography decreased whilst CT angiography and the number of imaging modalities applied to each patient increased over time (P < 0.001). Overall, 5.9% of CEAs were complicated by death, stroke or acute myocardial infarction with no significant change over time.

CONCLUSION

The trends in CEA practice at our centre align with international trends and guidelines. This study provides a representative indicator of Australian hospital practice, and illustrates how evidence from research is translated into clinical care.

Implementation of evidence-based stroke care: enablers, barriers, and the role of facilitators

A stroke care strategy was developed in 2007 to improve stroke services in Victoria, Australia. Eight stroke network facilitators (SNFs) were appointed in selected hospitals to enable the establishment of stroke units, develop thrombolysis services, and implement protocols. We aimed to explain the main issues being faced by clinicians in providing evidence-based stroke care, and to determine if the appointment of an SNF was perceived as an acceptable strategy to improve stroke care. Face-to-face semistructured interviews were used in a qualitative research design. Interview transcripts were verified by respondents prior to coding. Two researchers conducted thematic analysis of major themes and subthemes. Overall, 84 hospital staff participated in 33 interviews during 2008. The common factors found to impact on stroke care included staff and equipment availability, location of care, inconsistent use of clinical pathways, and professional beliefs. Other barriers included limited access to specialist clinicians and workload demands. The establishment of dedicated stroke units was considered essential to improve the quality of care. The SNF role was valued for identifying gaps in care and providing capacity to change clinical processes. This is the first large, qualitative multicenter study to describe issues associated with delivering high-quality stroke care and the potential benefits of SNFs to facilitate these improvements.

Abstract W P177: Direct to CT: Overcoming Barriers to Reduce Door to Needle times in Acute Stroke Patients

Background: Taking acute stroke patients direct from triage to the CT scanner can reduce thrombolysis treatment times, which can improve patient outcomes. In May 2013, Box Hill Hospital introduced a Direct to CT policy for acute stroke patients who are called through as a Code Stroke by the ambulance service within business hours (8am-4.30pm) Monday to Friday.

Method: We performed a prospective study comparing door-to-CT times (DTCT) and door-to-needle (DTN) times pre- and post-implementation of Direct to CT, and examined patient characteristics, Emergency Department (ED) presentation time, adverse effects, protocol violations and patient outcomes. Delays in treatment, enablers and barriers to treatment were also examined.

Results: There was no statistical difference in demographics or clinical factors in patients who presented pre- (January-April, n=21) or post- Direct to CT (May-July, n=29). However, a reduction in median DTCT times (27 mins vs. 16 mins, p=0.01) and DTN times (97 mins vs. 52 mins, p<0.001) was seen. There was no increase in thrombolysed mimics (4.8% vs. 3.4%, p=0.82), protocol violations (9.5% vs. 0%, p=0.17) or adverse outcomes (33% vs. 35%, p=0.93) in patients taken Direct to CT. There was no difference in patient outcomes, however the current study size is small. Numerous barriers to Direct to CT were identified within four categories: pre-hospital, ED, CT and the stroke team, and issues included: lack of paramedic intravenous cannulation, ED resources, and stroke team indecisions; some of which are ongoing and are taking considerable time and efforts to overcome.

Conclusions: Taking patients Direct to CT has significantly reduced time to treatment and further improvements may be achieved through resolution of identified barriers.

STroke imAging pRevention and Treatment (START): A Longitudinal Stroke Cohort Study: Clinical Trials Protocol

Rationale

Stroke and poststroke depression are common and have a profound and ongoing impact on an individual's quality of life. However, reliable biological correlates of poststroke depression and functional outcome have not been well established in humans.

Aims

Our aim is to identify biological factors, molecular and imaging, associated with poststroke depression and recovery that may be used to guide more targeted interventions.

Design

In a longitudinal cohort study of 200 stroke survivors, the START – STroke imAging pRevention and Treatment cohort, we will examine the relationship between gene expression, regulator proteins, depression, and functional outcome. Stroke survivors will be investigated at baseline, 24 h, three-days, three-months, and 12 months poststroke for blood-based biological associates and at days 3–7, three-months, and 12 months for depression and functional outcomes. A sub-group ( n = 100), the PrePARE: Prediction and Prevention to Achieve optimal Recovery Endpoints after stroke cohort, will also be investigated for functional and structural changes in putative depression-related brain networks and for additional cognition and activity participation outcomes. Stroke severity, diet, and lifestyle factors that may influence depression will be monitored. The impact of depression on stroke outcomes and participation in previous life activities will be quantified.

Study Outcomes

Clinical significance lies in the identification of biological factors associated with functional outcome to guide prevention and inform personalized and targeted treatments. Evidence of associations between depression, gene expression and regulator proteins, functional and structural brain changes, lifestyle and functional outcome will provide new insights for mechanism-based models of poststroke depression.

Abstract TP251: The Direct and Indirect Impact of the Acute Stroke Nurse Role on Thrombolysis Treatment Times and Rates

Background: The Acute Stroke Nurse (ASN) role at Box Hill Hospital is a business hours (weekday 8am - 4.30pm) first responder role designed to fast track acute stroke patients through thrombolysis screening in the Emergency Department. Since 2004, this role has been filled in either a full-time (FT) or part-time (PT) capacity, except for a 5-month period in 2010 where the role was vacant. We sought to explore the influence of having a full-time ASN, compared to part-time or no ASN, on thrombolysis rates and times.

Methods: Data was extracted from the hospital’s stroke thrombolysis database for the period 2004 to 2012. Comparisons were made for those patients seen by the ASN, when FT and PT and those who saw medical staff only. Statistical comparisons were made using Mann-Whitney Rank Sum test.

Results: Almost half (43% n=182) of the 428 thrombolysis cases occurred during business hours, the ASN attended 84% of cases when the role was filled FT and 15% when PT. No difference was seen in median door-to-CT times (25 minutes.) Faster median door-to-needle times were achieved during business hours when the patient was seen by the ASN compared to those who were not (66 mins vs. 83 mins, p=<0.001.) Faster times were seen when the ASN role was FT (68 min) or PT (79 min) compared to vacant (89 mins, p=0.006,) with more patients treated within 60 minutes of arrival (35% FT, 27% PT and 8% vacant, NS). While the ASN only works within business hours, faster door-to-needle times were seen after hours when the ASN role was filled FT and PT compared to vacant (87mins and 100 mins vs. 103 mins, p=0.013;) and treatment was only commenced under 60 minutes when the ASN was employed FT.

Conclusion: The Acute Stroke Nurse role seems to have a positive impact on thrombolysis treatment times and rates, with the best results being achieved during and outside business hours when the ASN is employed FT.

A multicentre, randomized, double-blinded, placebo-controlled Phase III study to investigate EXtending the time for Thrombolysis in Emergency Neurological Deficits (EXTEND)

BACKGROUND AND HYPOTHESIS

Thrombolytic therapy with tissue plasminogen activator is effective for acute ischaemic stroke within 4·5 h of onset. Patients who wake up with stroke are generally ineligible for stroke thrombolysis. We hypothesized that ischaemic stroke patients with significant penumbral mismatch on either magnetic resonance imaging or computer tomography at three- (or 4·5 depending on local guidelines) to nine-hours from stroke onset, or patients with wake-up stroke within nine-hours from midpoint of sleep duration, would have improved clinical outcomes when given tissue plasminogen activator compared to placebo.

STUDY DESIGN

EXtending the time for Thrombolysis in Emergency Neurological Deficits is an investigator-driven, Phase III, randomized, multicentre, double-blind, placebo-controlled study. Ischaemic stroke patients presenting after the three- or 4·5-h treatment window for tissue plasminogen activator and within nine-hours of stroke onset or with wake-up stroke within nine-hours from the midpoint of sleep duration, who fulfil clinical (National Institutes of Health Stroke Score ≥4-26 and prestroke modified Rankin Scale <2) will undergo magnetic resonance imaging or computer tomography. Patients who also meet imaging criteria (infarct core volume <70 ml, perfusion lesion : infarct core mismatch ratio >1·2, and absolute mismatch >10 ml) will be randomized to either tissue plasminogen activator or placebo.

STUDY OUTCOME

The primary outcome measure will be modified Rankin Scale 0-1 at day 90. Clinical secondary outcomes include categorical shift in modified Rankin Scale at 90 days, reduction in the National Institutes of Health Stroke Score by 8 or more points or reaching 0-1 at day 90, recurrent stroke, or death. Imaging secondary outcomes will include symptomatic intracranial haemorrhage, reperfusion and or recanalization at 24 h and infarct growth at day 90.

Stroke public awareness campaigns have increased ambulance dispatches for stroke in Melbourne, Australia

BACKGROUND AND PURPOSE

Launch of the National Stroke Foundation stroke awareness campaigns has occurred annually during Stroke Week (September) since 2004. From 2006, the campaign used FAST (Face, Arm, Speech, Time) with calling an ambulance added in 2007. The aim of this study was to explore the impact of these campaigns on ambulance dispatches for stroke (Medical Priority Dispatch Card 28) in Melbourne, Australia.

METHODS

A cross-sectional study examining the monthly proportions of ambulance dispatches for stroke between August 1999 and 2010 was conducted. The proportions of dispatches for stroke were used due to increases in the population and in ambulance dispatches over the study period. These proportions were statistically compared for the month before Stroke Week (August) and the month after Stroke Week (October) for each year and seasonal variation was examined.

RESULTS

Between 1999 and 2009, the annual proportion of dispatches for stroke increased from 2.1% (n=4327) to 2.95% (n=9918). When stroke dispatches in August were compared with those in October, a significant increase in October was only detected since the call an ambulance message was added to FAST: 2007 (2.62% to 3.00%, P=0.006), 2008 (2.62% to 3.05%, P=0.003), and 2009 (2.70% to 3.09%, P=0.007). From 2005, the peak season for stroke dispatches shifted from winter to spring.

CONCLUSIONS

Ambulance dispatches for stroke significantly increased after the National Stroke Foundation campaigns began, particularly in years receiving greater funding and featuring the FAST symptoms and the message to call an ambulance. Monitoring ambulance use appears to be an effective measure of campaign penetration.

Is FAST Stroke Smart? Do the Content and Language used in Awareness Campaigns Describe the Experience of Stroke Symptoms?

Background

Public education campaigns for stroke are used worldwide. However, there are few published evaluations of such campaigns.

Aim

This cross-sectional study examined patient and bystander awareness of two Australian campaigns, ‘FAST’ (face, arm, speech, time) and ‘Signs of Stroke’, and evaluated the campaigns ability to identify stroke and to describe the symptom experience.

Methods

Interviews were conducted with either stroke patients or a key bystander for consecutive eligible cases admitted to two metropolitan hospitals between August 2006 and April 2008. Participants were asked to describe awareness of the FAST campaign, the symptoms experienced and to evaluate the symptom descriptions of Signs of Stroke against their own experience.

Results

A total of 100 patients and 70 bystanders were interviewed for 170 cases (71% of eligible cases). Only 12% of those interviewed were aware of the FAST campaign, and of these few (19%) were able to recall all FAST symptoms, with only one bystander using the FAST assessments to identify stroke. At least one FAST symptom was reported by 84% and one Signs of Stroke symptom by 100%. Less than half of those experiencing ‘weakness or paralysis’ thought this description exactly described their experience. Common descriptors of symptoms were: face or mouth droop or drop; trouble using, coordinating or moving arm, hand or leg; trouble walking or standing; numbness; and slurring or loss of speech.

Conclusion

Awareness of the FAST and Signs of Stroke campaigns was low, with poor recall and little use of the FAST assessments. Some symptom descriptions used in the campaign were not reflective of the symptom experience. The content and language of these campaigns could be improved to portray stroke symptoms more realistically.

Paramedic diagnosis of stroke: examining long-term use of the Melbourne Ambulance Stroke Screen (MASS) in the field

BACKGROUND AND PURPOSE

Recent evidence suggests the Cincinnati Prehospital Stroke Scale is ineffectively used and lacks sensitivity and specificity. Melbourne (Australia) paramedics have been using the Melbourne Ambulance Stroke Screen (MASS) since 2005. The aim of this study was to review the real-world use of MASS 3 years after city wide implementation.

METHODS

Two groups of consecutively admitted patients to an Australian hospital between January and May 2008 were used: (1) patients for whom paramedics performed MASS; and (2) patients with a discharge diagnosis of stroke or transient ischemic attack. Use of MASS was examined for all transports and for patients diagnosed with stroke or transient ischemic attack. The sensitivity and specificity of paramedic diagnosis, MASS, and Cincinnati Prehospital Stroke Scale were calculated. Paramedic diagnosis of stroke among patients with stroke was statistically compared with those obtained immediately post-MASS implementation in 2002.

RESULTS

For the study period, MASS was performed for 850 (16%) of 5286 emergency transports, including 199 of 207 (96%) patients with confirmed stroke and transient ischemic attack. In patients in whom MASS was performed (n=850), the sensitivity of paramedic diagnosis of stroke (93%, 95% CI: 88% to 96%) was higher than the MASS (83%, 95% CI: 77% to 88%, P=0.003) and equivalent to Cincinnati Prehospital Stroke Scale (88%, 95% CI: 83% to 92%, P=0.120), whereas the specificity of the paramedic diagnosis of stroke (87%, 95% CI: 84% to 89%) was equivalent to MASS (86%, 95% CI: 83% to 88%, P=0.687) and higher than Cincinnati Prehospital Stroke Scale (79%, 95% CI: 75% to 82%, P<0.001). The initial improvement in stroke paramedic diagnosis seen in 2002 (94%, 95% CI: 86% to 98%) was sustained in 2008 (89%, 95% CI: 84% to 94%, P=0.19).

CONCLUSIONS

In our experience, paramedics have successfully incorporated MASS into the assessment of neurologically compromised patients. The initial improvement to the paramedics' diagnosis of stroke with MASS was sustained 3 years after city wide implementation.

Time to treatment with intravenous alteplase and outcome in stroke: an updated pooled analysis of ECASS, ATLANTIS, NINDS, and EPITHET trials

BACKGROUND

Early administration of intravenous recombinant tissue plasminogen activator (rt-PA) after ischaemic stroke improves outcome. Previous analysis of combined data from individual patients suggested potential benefit beyond 3 h from stroke onset. We re-examined the effect of time to treatment with intravenous rt-PA (alteplase) on therapeutic benefit and clinical risk by adding recent trial data to the analysis.

METHODS

We added data from ECASS III (821 patients) and EPITHET (100 patients) to a pool of common data elements from six other trials of alteplase for acute stroke (2775 patients). We used multivariate logistic regression to assess the relation of stroke onset to start of treatment (OTT) with treatment on favourable 3-month outcome (defined as modified Rankin score 0-1), mortality, and occurrence and outcome of clinically relevant parenchymal haemorrhage. The presence of an arterial occlusion was inferred from the patient's symptoms and absence of haemorrhage or other causes of ischaemic stroke. Vascular imaging was not a requirement in the trials. All patients with confirmed OTT within 360 min were included in the analysis.

FINDINGS

Treatment was started within 360 min of stroke onset in 3670 patients randomly allocated to alteplase (n=1850) or to placebo (n=1820). Odds of a favourable 3-month outcome increased as OTT decreased (p=0.0269) and no benefit of alteplase treatment was seen after around 270 min. Adjusted odds of a favourable 3-month outcome were 2.55 (95% CI 1.44-4.52) for 0-90 min, 1.64 (1.12-2.40) for 91-180 min, 1.34 (1.06-1.68) for 181-270 min, and 1.22 (0.92-1.61) for 271-360 min in favour of the alteplase group. Large parenchymal haemorrhage was seen in 96 (5.2%) of 1850 patients assigned to alteplase and 18 (1.0%) of 1820 controls, with no clear relation to OTT (p=0.4140). Adjusted odds of mortality increased with OTT (p=0.0444) and were 0.78 (0.41-1.48) for 0-90 min, 1.13 (0.70-1.82) for 91-180 min, 1.22 (0.87-1.71) for 181-270 min, and 1.49 (1.00-2.21) for 271-360 min.

INTERPRETATION

Patients with ischaemic stroke selected by clinical symptoms and CT benefit from intravenous alteplase when treated up to 4.5 h. To increase benefit to a maximum, every effort should be taken to shorten delay in initiation of treatment. Beyond 4.5 h, risk might outweigh benefit.

FUNDING

None.

Baseline diabetic status and admission blood glucose were poor prognostic factors in the EPITHET trial

BACKGROUND

Previous data have suggested that diabetes and hyperglycemia predict poor outcome following stroke. We studied the prognostic impact of diabetes and admission blood glucose in the Echoplanar Imaging Thrombolytic Evaluation Trial (EPITHET).

METHODS

EPITHET was a prospective randomized placebo-controlled trial of intravenous tissue plasminogen activator (tPA) in the 3- to 6-hour time window. A preexisting diagnosis of diabetes was noted and baseline serum glucose was measured.

RESULTS

Intravenous tPA attenuated infarct growth in non-diabetics, but not in diabetics (p = 0.029). In the tPA treatment group, admission blood glucose was higher among patients with poor functional outcome (p = 0.002).

CONCLUSIONS

Diabetes and hyperglycemia attenuate the effects of tPA on infarct evolution. Future thrombolytic trials should consider randomizing patients by subgroups based on diabetic status and serum glucose levels.

Effects of the end point adjudication process on the results of the Perindopril Protection Against Recurrent Stroke Study (PROGRESS)

BACKGROUND AND PURPOSE

End point adjudication committees (EPAC) are widely used in large-scale clinical trials to ensure the robustness of diagnosis for end points.

METHODS

The Perindopril Protection Against Recurrent Stroke Study (PROGRESS) was a double-blind randomized trial of blood pressure lowering in 6105 participants with pre-existing cerebrovascular disease. Separate estimates of the effects of randomized treatment were determined using Cox regression models that were based on the unadjudicated events initially reported by the investigator and on the final events assigned by the EPAC.

RESULTS

There were 992 strokes initially reported by the investigators and 894 (90%) retained these diagnoses after adjudication by the EPAC. The hazard ratios (95% CIs) for the effect of randomized treatment on stroke were 0.74 (0.64 to 0.85) based on the investigator diagnoses and 0.72 (0.62 to 0.83) based on the EPAC diagnoses (P homogeneity=0.7). For each stroke subtype reported, the corresponding numbers of diagnoses (investigators/EPAC) were ischemic (593/565), hemorrhagic (124/111), and unknown (124/93) with no impact of the EPAC review on the estimates of treatment effects (all P homogeneity >0.3). There was likewise no detectable effect of reclassification of diagnoses for the effect estimates calculated for myocardial infarction or the main causes of death (all P homogeneity >0.5).

CONCLUSIONS

The EPAC process had no discernible impact on the trial conclusions. Very large trials powered to detect effects on stroke subtypes might obtain real scientific gain from an EPAC, but in the case of PROGRESS, the value of the EPAC was in the reassurance it provided.

Thrombolytic therapy for acute ischaemic stroke: successful implementation in an Australian tertiary hospital

The use of tissue-type plasminogen activator (t-PA) in ischaemic stroke outside of experienced stroke centres remains controversial. The aim of this study was to present the initial experience with t-PA in patients with ischaemic stroke at an institution with no prior experience in i.v. stroke thrombolysis and to compare results to published reports. Prospective audit of 888 patients with consecutive stroke and transient ischaemic attack admitted to a 426-bed tertiary referral hospital from March 2003 to October 2005. Main outcome measures were treatment rate, exclusion criteria, protocol violations, intracerebral haemorrhage, disability (modified Rankin scale) and mortality at 3 months. Over the study period, 72 patients received t-PA (11% of ischaemic strokes). The main reason for exclusion was presentation beyond 3 h of onset (44%); if all eligible patients had arrived within 3 h, treatment rate was estimated at 32.5%. Protocol violations occurred in 15 (21%) patients. There were seven (10%) asymptomatic intracerebral haemorrhage and one (1%) non-fatal symptomatic intracerebral haemorrhage. At 3 months, 37% had achieved excellent recovery (modified Rankin scale 0-1) and seven (10%) had died. The delivery and outcomes associated with the use of t-PA were comparable to the results of the National Institute of Neurological Disorders and Stroke trial and meta-analysis of open-labelled studies. With appropriate infrastructure and protocols, previously inexperienced tertiary referral centres can replicate the experience and outcome measures reported by clinical trials of t-PA in patients with stroke.

Refining the perfusion-diffusion mismatch hypothesis

BACKGROUND AND PURPOSE

The Echoplanar Imaging Thrombolysis Evaluation Trial (EPITHET) tests the hypothesis that perfusion-weighted imaging (PWI)-diffusion-weighted imaging (DWI) mismatch predicts the response to thrombolysis. There is no accepted standardized definition of PWI-DWI mismatch. We compared common mismatch definitions in the initial 40 EPITHET patients.

METHODS

Raw perfusion images were used to generate maps of time to peak (TTP), mean transit time (MTT), time to peak of the impulse response (Tmax) and first moment transit time (FMT). DWI, apparent diffusion coefficient (ADC), and PWI volumes were measured with planimetric and thresholding techniques. Correlations between mismatch volume (PWIvol-DWIvol) and DWI expansion (T2(Day 90-vol)-DWI(Acute-vol)) were also assessed.

RESULTS

Mean age was 68+/-11, time to MRI 4.5+/-0.7 hours, and median National Institutes of Health Stroke Scale (NIHSS) score 11 (range 4 to 23). Tmax and MTT hypoperfusion volumes were significantly lower than those calculated with TTP and FMT maps (P<0.001). Mismatch > or =20% was observed in 89% (Tmax) to 92% (TTP/FMT/MTT) of patients. Application of a +4s (relative to the contralateral hemisphere) PWI threshold reduced the frequency of positive mismatch volumes (TTP 73%/FMT 68%/Tmax 54%/MTT 43%). Mismatch was not significantly different when assessed with ADC maps. Mismatch volume, calculated with all parameters and thresholds, was not significantly correlated with DWI expansion. In contrast, reperfusion was correlated inversely with infarct growth (R=-0.51; P=0.009).

CONCLUSIONS

Deconvolution and application of PWI thresholds provide more conservative estimates of tissue at risk and decrease the frequency of mismatch accordingly. The precise definition may not be critical; however, because reperfusion alters tissue fate irrespective of mismatch.

Intercenter agreement in reading Doppler embolic signals. A multicenter international study

BACKGROUND AND PURPOSE

Different frequencies of asymptomatic Doppler embolic signals have been reported in studies. There has been concern that different criteria for identification may account for some of this variation. A previous reproducibility study between two centers found good agreement, but no studies among large numbers of centers have been performed. We performed an international reproducibility study among nine centers, each of which had published recent studies of embolic signal detection in peer-reviewed journals.

METHODS

Each center performed blinded analysis of a taped audio Doppler signal composed of transcranial Doppler middle cerebral artery recordings from 6 patients with symptomatic carotid artery stenosis. The exact time of any embolic signal was recorded. Six centers also measured the intensity increase of any embolic signals detected. Interobserver agreement was determined by a method based on the proportion of specific agreement.

RESULTS

Seven centers reported between 39 and 55 signals, but one center reported 142 embolic signals. The probability of agreement between observers was .678, which rose to .791 when the data from the highest reporting center were excluded. Introducing a decibel threshold resulted in a significant increase in the probability of agreement; a decibel threshold of > 7 dB resulted in a probability of agreement of .902. Intensity measurements made by different centers were usually highly correlated, but this was not always the case, and 3 of the 15 correlations were not significant. The absolute values of the intensities measured varied between centers by as much as 40%.

CONCLUSIONS

Although most centers report similar numbers of embolic signals, some use less specific criteria and report more events. The use of a decibel threshold improves reproducibility. However, intensity thresholds developed by one center cannot be directly transferred without validation to another center; differing methods of measurement are being used, and this results in different intensity values for the same embolic signals, even when the same equipment is used.

Fractures of the lateral process of the talus: a clinical review. "Snowboarder's ankle"

OBJECTIVE

This is a review article discussing the incidence, aetiology, investigation, and management of fractures of the lateral process of the talus, an uncommon but increasingly recognised complication of snowboarding.

DATA SOURCES

The data regarding aetiology, investigation, and management of these fractures were obtained through a comprehensive literature review utilising the Medline, Sport discus, Medline Orthopaedic, and Cinahl databases. Injury data were obtained through published prospective epidemiological studies of snowboarding injuries.

STUDY SELECTION

All studies of talar fractures, particularly of the lateral process, were included in the review. All prospective and retrospective studies of snowboarding injuries were reviewed.

DATA SYNTHESIS

The mechanism of this injury appears to be a combination of dorsiflexion and inversion of the ankle. The combination of soft-shell snowboarding boots and aerial maneuvers increase the likelihood of injury. Clinically these injuries resemble severe ligamentous ankle sprains and are commonly misdiagnosed. The fractures can be classified into three subtypes based on the severity of the bony injury. The management of each injury subtype differs and although no prospective treatment trials have been performed the published risk of long term degenerative subtalar joint damage warrant aggressive early management of this injury.

CONCLUSIONS

With the increasing popularity of snowboarding, the possibility of this injury should be considered in all ankle injuries related to this sport. Once diagnosed, management guidelines should be followed in order to minimise long term problems.

Snowboarding injuries. An overview

Over the last 10 years, snowboarding has become established as a popular and legitimate alpine sport. However, at present, there are few epidemiological studies examining the spectrum of injuries associated with this new sport. Snowboarders are typically male (male: female ratio of 3:1) and in their early twenties. They have an injury rate of 4 to 6 per 1000 visits, which is comparable to that which occurs with skiing. However, in contrast to skiing, in which only 34% of those injured are beginners, the majority (60%) of snowboarders injured are beginners. This is a reflection of the participant profile of this developing sport. 57% of injuries occur in the lower limbs, and 30% in the upper limbs. The most common injuries are simple sprains (31 to 53%), particularly of the ankles (23 to 26%) and knees (12 to 23%), followed by fractures (24 to 27%) and contusions (12%). Compared with skiing injuries, snowboarders have 2.4 times as many fractures, particularly of the upper limbs (constituting 21 vs 35% of upper limb injuries), fewer knee injuries (23 vs 44% of lower limb injuries), but more ankle injuries (23 vs 6% of lower limb injuries). Snowboarding knee injuries are less severe than those associated with skiing. Fracture of the lateral process of the talus is an unusual and uncommon snowboarding injury that can be misdiagnosed as a severe ankle sprain. Ankle injuries are more common with soft shell boots, whereas knee injuries and distal tibia fractures are more common with hard shell boots.(ABSTRACT TRUNCATED AT 250 WORDS)

Australian snowboard injury data base study. A four-year prospective study

Information on the rate and spectrum of snowboarding injuries is limited. This 4-year prospective study at 3 major Australian ski resorts assesses incidence and patterns of snowboarding injuries, particularly in relation to skill level and footwear. Ski injury data were collected for the same period. In a predominantly male study population (men:women, 3:1), 276 snowboarding injuries were reported; 58% occurred in novices. Fifty-seven percent of injuries were in the lower limbs, 30% in the upper limbs. The most common injuries were sprains (53%), fractures (24%), and contusions (12%). Comparing skiers' versus snowboarders' injuries, snowboarders had 2.4 times as many fractures, particularly to the upper limbs (21% versus 35% of upper limb injuries), fewer knee injuries (23% versus 44% of lower limb injuries), but more ankle injuries (23% versus 6% of lower limb injuries). Ankle injuries were more common with soft-shell boots, worn most by intermediate and advanced riders. Knee injuries and distal tibial fractures were more common with hard-shell boots, worn most by novices. Overall, novices had more upper limb fractures and knee injuries; intermediate and advanced riders had more ankle injuries. Falls were the principal mode of injury. To prevent injury, beginners should use "hybrid" or soft-shell boots and take lessons.

Repair of veno-occlusive disease of the lower limb using internal iliac vein graft and distal A-V anastomosis

A patient with longstanding chronic venous obstruction due to occlusion of the femoral vein, was subjected to vein graft repair with adjuvant A-V fistula. The repair failed but the fistula stimulated collateral development to alleviate symptoms.

Acquisition of skills required for use of Doppler ultrasound and the assessment of varicose veins

Doppler ultrasound is a useful adjunct to clinical examination for varicose veins. A simple study demonstrated that someone inexperienced in the use of a Doppler ultrasound can rapidly acquire sufficient expertise to use the instrument effectively.