Hyperacute Stroke Unit Research Articles

The impact of the UK COVID-19 pandemic on patient-reported health outcomes after stroke: a retrospective sequential comparison

Background and purposeThe COVID-19 pandemic and related social isolation measures are likely to have adverse consequences on community healthcare provision and outcome after acute illnesses treated in hospital, including stroke. We aimed to evaluate the impact of the COVID-19 pandemic on patient-reported health outcomes after hospital admission for acute stroke.MethodsThis retrospective study included adults with acute stroke admitted to the University College Hospital NHS Foundation Trust Hyperacute Stroke Unit. We included two separate cohorts of consecutively enrolled patients from the same geographical population at two time points: 16th March–16th May 2018 (pre-COVID-19 pandemic); and 16th March–16th May 2020 (during the COVID-19 pandemic). Patients in both cohorts completed the validated Patient Reported Outcomes Measurement Information System–29 (PROMIS-29 version 2.0) at 30 days after stroke.ResultsWe included 205 patients who were alive at 30 days (106 admitted before and 99 admitted during the COVID-19 pandemic), of whom 201/205 (98%) provided patient-reported health outcomes. After adjustment for confounding factors, admission with acute stroke during the COVID-19 pandemic was independently associated with increased anxiety (β = 28.0, p < 0.001), fatigue (β = 9.3, p < 0.001), depression (β = 4.5, p = 0.002), sleep disturbance (β = 2.3, p = 0.018), pain interference (β = 10.8, p < 0.001); and reduced physical function (β = 5.2, p < 0.001) and participation in social roles and activities (β = 6.9, p < 0.001).ConclusionCompared with the pre-pandemic cohort, patients admitted with acute stroke during the first wave of the COVID-19 pandemic reported poorer health outcomes at 30 day follow-up in all domains. Stroke service planning for any future pandemic should include measures to mitigate this major adverse impact on patient health.

Do methods of hospital pre-alerts influence the on-scene times for acute pre-hospital stroke patients? A retrospective observational study.

Introduction:Stroke is one of the leading causes of death and disability worldwide. The ambulance service is often the first medical service to reach an acute stroke patient, and due to the time-critical nature of stroke, a time-critical assessment and rapid transport to a hyper acute stroke unit are essential. As stroke services have been centralised, different hospitals have implemented different pre-alert admission policies that may affect the on-scene time of the attending ambulance crew. The aim of this study is to investigate if the different pre-alert admission policies affect time on scene.Method:The current study is a retrospective quantitative observational study using data routinely collected by North East Ambulance Service NHS Foundation Trust. The time on scene was divided into two variables; group one was a telephone pre-alert in which a telephone discussion with the receiving hospital is required before they accept admission of the patient. Group two was a radio-style pre-alert in which the attending clinician makes an autonomous decision on the receiving hospital and alerts them via a short radio message of the incoming patient. These times were then compared to identify if there was any difference between them.Results:Data on 927 patients over a three-month period, from October to December 2019, who had received the full stroke bundle of care, were within the thrombolysis window and recorded as a stroke by the attending clinician, were split into the variable groups and reported on. The mean time on scene for a telephone call pre-alert was 33 minutes and 19 seconds, with a standard deviation of 13 minutes and 8 seconds. The mean on-scene time for a radio pre-alert was 28 minutes and 24 seconds, with a standard deviation of 11 minutes and 51 seconds.Conclusion:A pre-alert given via radio instead of via telephone is shown to have a mean time saving of 4 minutes and 55 seconds, representing an important decrease in time which could be beneficial to patients.

Reducing potentially avoidable tasks in a hyperacute stroke unit

The workflow in a stroke unit can be very high, and this is especially noticeable during evening and night shifts, where staffing is reduced but the patient’s need for frequent...

Adverse consequences of immediate thrombolysis-related complications: a multi-centre registry-based cohort study of acute stroke

Complications following thrombolysis for stroke are well documented, and mostly concentrated on haemorrhage. However, the consequences of patients who experience any immediate thrombolysis-related complications (TRC) compared to patients without immediate TRC have not been examined. Prospectively collected data from the Sentinel Stroke National Audit Programme were analysed. Thrombolysis was performed in 451 patients (52.1% men; 75.3 years ± 13.2) admitted with acute ischaemic stroke (AIS) in four UK centres between 2014 and 2016. Adverse consequences following immediate TRC were assessed using logistic regression, adjusted for age, sex and co-morbidities. Twenty-nine patients (6.4%) acquired immediate TRC. Compared to patients without, individuals with immediate TRC had greater adjusted risks of: moderately-severe or severe stroke (National Institutes of Health for Stroke Scale score ≥ 16) at 24-h (5.7% vs 24.7%, OR 3.9, 95% CI 1.4–11.1); worst level of consciousness (LOC) in the first 7 days (score ≥ 1; 25.0 vs 60.7, OR 4.6, 95% CI 2.1–10.2); urinary tract infection or pneumonia within 7-days of admission (13.5% vs 39.3%, OR 3.2, 95% CI 1.3–7.7); length of stay (LOS) on hyperacute stroke unit (HASU) ≥ 2 weeks (34.7% vs 66.7%, OR 5.2, 95% CI 1.5–18.4); mortality (13.0% vs 41.4%, OR 3.7, 95% CI 1.6–8.4); moderately-severe or severe disability (modified Rankin Scale score ≥ 4) at discharge (26.8% vs 65.5%, OR 4.7, 95% CI 2.1–10.9); palliative care by discharge date (5.1% vs 24.1%, OR 5.1, 95% CI 1.7–15.7). The median LOS on the HASU was longer (7 days vs 30 days, Kruskal–Wallis test: χ2 = 8.9, p = 0.003) while stroke severity did not improve (NIHSS score at 24-h post-thrombolysis minus NIHSS score at arrival = − 4 vs 0, χ2 = 24.3, p < 0.001). In conclusion, the risk of nosocomial infections, worsening of stroke severity, longer HASU stay, disability and death is increased following immediate TRC. The management of patients following immediate TRC is more complex than previously thought and such complexity needs to be considered when planning an increased thrombolysis service.

Prevalence of acute dizziness and vertigo in cortical stroke.

In posterior circulation stroke, vertigo can be a presenting feature. However, whether isolated hemispheric strokes present with vertigo is less clear, despite a few single case reports in the literature. Here, (a) the prevalence of vertigo/dizziness in acute stroke is explored and (b) the cortical distribution of the lesions in relation to both the known vestibular cortex and the evolution of the symptoms, are considered. Structured interviews were conducted in 173 consecutive unselected patients admitted to the hyperacute stroke unit at the University College London Hospitals. The interview was used to evaluate whether the patient was suffering from dizziness and/or vertigo before the onset of the stroke and at the time of the stroke (acute dizziness/vertigo), and the nature of these symptoms. In all, 53 patients had cortical infarcts, of which 21 patients reported acute dizziness. Out of these 21, five patients reported rotational vertigo. Seventeen of the total 53 patients had lesions in known vestibular cortical areas distributed within the insular and parietal opercular cortices. The prevalence of vertigo in acute cortical strokes was 9%, with no single locus of lesion overlap. There is growing evidence supporting a lateralized vestibular cortex, with speculation that cortical strokes affecting the right hemisphere are more likely to cause vestibular symptoms than left hemispheric strokes. A trend was observed for this association, with the right hemisphere affected in four of five patients who reported spinning vertigo at the onset of the stroke.

The Vwf-ADAMTS13 Axis in Acute Ischaemic Brain Injury: a Prospective Study

Background:Acute ischaemic brain injury is associated with raised von Willebrand factor (vWF) and decreased ADAMTS13. Mouse data suggested manipulation of either factor has a direct impact on infarct volume, impacting functional outcome. Preliminary clinical data supports a role in arterial thrombosis severity and recurrence risk. We investigate the VWF: ADAMTS axis in acute stroke and impact on follow up.Methods:A prospective study in adults of vWF-ADAMTS13 in acute ischaemic brain injury, recruited from regional hyperacute stroke unit referrals and TIA (transient ischaemic attack) clinic. Exclusion included secondary precipitating causes such as known active malignancy. The control group were cases admitted with possible stroke, subsequently excluded. Blood was sampled at presentation, daily during admission, 7 -10 days post presentation and from 6 weeks post presentation. Clinical phenotype and stroke scoring parameters were documented. vWF (antigen- Ag, activity- Ac), Factor VIII, ADAMTS13- activity and thrombin generation (peak thrombin and endogenous thrombin potential-ETP) were analysed.Results:291 patients (140 males, 151 females), aged 23 -100 years. Patients were categorized into ischaemic stroke (IS, n=103), TIA (n=80) or controls (n=108). IS: At presentation, ADAMTS13 was lower in IS compared to controls (median 86.0IU/dL vs 95.7IU/dL, p<0.0001) and TIAs (median 94.0IU/dL, p<0.0001). vWFAg was higher in IS versus controls (median 196.9IU/dL vs 160.8 IU/dL, p=0.0007) and TIA (median 167.8IU/dL, p=0.0194). Comparable significant findings for vWFAc were confirmed. Longer-term follow up (> 6 weeks since admission) in 62 patients, IS demonstrated increased ADAMTS13 from presentation to final follow up (86.0 to 97.4 IU/dL, p=0.01). There was a significant increase in median ADAMTS13 across all time points (p=0.0388) with median final follow up at 215 days (72- 394). The reverse was seen with vWFAg, vWFAc and Factor VIII in IS, with significant decrease over time. The vWFAg/ ADAMTS13 ratio decreased over time (2.42 to 1.53, p=0.0007) in IS as did thrombin generation (presentation vs final follow up respectively, peak: 262.6nM to 184.1nM, p=0.041; ETP: 1691nM/min to 1345nM/min, p=0.0251). Impact of thrombolysis: In IS, 38/103 were thrombolysed. Peak thrombin and endogenous thrombin generation (ETP) were raised at baseline in the thrombolysed cases compared to non-thrombolysed (p=0.0022 and 0.0012 respectively). Baseline ADAMTS13 was comparable between the groups, but the thrombolysed group showed increase at follow up (84 to 100.8 IU/dL, p=0.0005, median follow up 196 days) with no change in the non-thrombolysed group (86 to 80 IU/dL, p=0.955, median follow up 209 days). TIA : was divided between inpatient (IP, n=26) and outpatient (OP, n=54) cases. Baseline vWFAg, activity and FVIII were higher in IP compared to OP (vWFAg 229.5 vs 161.0, p=0.0029; vWFAc 199.8 vs 136.3, p=0.0173; FVIII 177.5 vs 131.3, p=0.0007). There was no difference in baseline ADAMTS13 (inpatients 95.3IU/dL vs outpatients 92.1IU/dL, p=0.505). Between baseline and follow up, the vWFAg/ ADAMTS13 ratio decreased but this was non-significant. Blood group was reviewed regarding impact on vWF. Comparing blood group O versus non-O showed significant differences in vWFAg, Ac and FVIII in the overall cohort. However, differences in vWFAg, vWFAc and ADAMTS13 were unchanged between IS and controls with adjustment for blood group (O versus non-O).Conclusion: Our findings support decreased ADAMTS13 in acute IS compared to TIA and control, with a reciprocal increase in vWFAg and vWFAc. Comparison of TIA in-patients to out-patients showed significantly higher vWFAg, Ac and FVIII in the former, in keeping with a more severe phenotype. ADAMTS13 was not decreased in TIAs. There was resolution of VWF: ADAMTS 13 in IS at follow up, supporting increased vWF levels and consumption of ADAMTS13 in acute stroke. Thrombolysis appeared associated with recovery of ADAMTS13 activity. Contrast between IS and TIA groups suggest association with infarct volume and consequent stroke severity, and may indicate a close role between the vWF-ADAMTS13 axis and thrombogenicity in acute ischaemic brain injury. In the era of recombinant ADAMTS13, therapeutic implications of reducing raised vWF levels and normalising ADAMTS13 activity merit further investigation. DisclosuresScully:Alexion: Honoraria; Novartis: Honoraria; Shire: Honoraria, Research Funding; Ablynx: Honoraria, Research Funding.

Extent of white matter lesion is associated with early hemorrhagic transformation in acute ischemic stroke related to atrial fibrillation.

BackgroundHemorrhagic transformation (HT) after stroke, related to atrial fibrillation (AF), is a frequent complication, and it can be associated with a delay in the (re‐)initiation of oral anticoagulation therapy. We investigated the effect of the presence and severity of white matter disease (WMD) on early HT after stroke related to AF.MethodsA consecutive series of patients with recent (<4 weeks) ischemic stroke and AF, treated at the Hyper Acute Stroke Unit of the Imperial College London between 2010 and 2017, were enrolled. Patients with brain MRI performed 24–72 h from stroke onset and not yet started on anticoagulant treatment were included. WMD was graded using the Fazekas score.ResultsAmong the 441 patients eligible for the analysis, 91 (20.6%) had any HT. Patients with and without HT showed similar clinical characteristics. Patients with HT had a larger diffusion‐weighted imaging (DWI) infarct volume compared to patients without HT (p < .001) and significant difference in the distribution of the Fazekas score (p = .001). On multivariable analysis, HT was independently associated with increasing DWI infarct volume (odd ratio (OR), 1.03; 95% confidence interval (CI), 1.01–1.05; p < .001), higher Fazekas scores (OR, 1.94; 95% CI, 1.47–2.57; p < .001) and history of previous intracranial hemorrhage (OR, 4.80; 95% CI, 1.11–20.80; p = .036).ConclusionsPresence and severity of WMD is associated with increased risk of development of early HT in patients with stroke and AF. Further evidence is needed to provide reliable radiological predictors of the risk of HT in cardioembolic stroke.

Differences in Characteristics and Ambulance Pathway Adherence Between Strokes and Mimics Presenting to a Large UK Centralized Hyper Acute Stroke Unit (HASU).

Background: In Greater Manchester (GM), prehospital clinicians use the Face Arm Speech Test (FAST) to identify suspected stroke patients alongside pathway exclusions. Within the centralized stroke service, patients with a suspected stroke are taken directly to a Hyper Acute Stroke Unit (HASU), often bypassing their local emergency department (ED). However, many of these patients are experiencing an illness that looks like a stroke but is not a stroke. The data collected in the prehospital setting is rarely used in research yet could give valuable insights into the performance of the pathway.Aim: To evaluate the presenting symptoms and final diagnoses of prehospital suspected strokes and to evaluate the adherence of prehospital stroke pathway exclusions.Methods: We analyzed data from all patients brought in by ambulance and admitted on the stroke pathway between 01/09/15 and 28/02/17. Patient demographics and all data recorded in the prehospital setting were evaluated to identify differences in stroke, TIA, and mimic patients. Pathway adherence was assessed according to whether the patient was local or out-of-area (OOA) and bypassed their local ED.Results: A total of 4,216 suspected strokes were identified: 2,213 (52.5%) had a final diagnosis of stroke, 492 (11.7%) experienced a transient ischemic attack (TIA), and 1,511 (35.8%) were stroke mimics. There were 714 (16.9%) patients that were identified as having at least one pathway exclusion or were FAST negative, of which 270 (37.8%) experienced a stroke. The proportion of strokes was significantly lower in those with a pathway exclusion (41.8 vs. 53.5%; p < 0.001) and the proportion of breaches tended to be comparable or higher in the local population.Discussion: There are high volumes of stroke mimics but identified differences indicate there is an opportunity to better utilize prehospital data. Ambulance clinicians were able to correctly overrule FAST negative results and the volume of these suggest that FAST alone may be too restrictive.

The neuropsychology needs of a hyper-acute stroke unit

Background and aimGuidelines recommend routine assessment and management of mood and cognition after stroke, but little is known about the value or feasibility of providing neuropsychology input during the hyper-acute period. We aimed to identify and describe the extent and nature of neuropsychological needs and to investigate the feasibility of providing direct neuropsychology input within a hyper-acute setting. MethodsOver a 7-month period, Multidisciplinary Team (MDT) members of a central London Hyper-Acute Stroke Unit (HASU) identified stroke patients who they believed would benefit from neuropsychology input, and categorised the nature of neuropsychology intervention required. We examined the demographic and clinical characteristics of the patients identified and the type of intervention required. Results23% of patients (101/448) were identified as requiring neuropsychology input. Patients deemed to require input were younger, more likely to be male and more functionally disabled than those not requiring input. Cognitive assessment was the main identified need (93%) followed by mood (29%) and family support (9%). 30% of patients required two types of intervention. During a pilot of neuropsychology provision, 17 patients were seen; 15 completed a full cognitive assessment. All patients assessed presented with cognitive impairment despite three being deemed cognitively intact (> standardised cut-off) using a cognitive screening tool. ConclusionWe showed that direct neuropsychology input on a HASU is necessary for complex and varied interventions involving cognition, mood and family support. Furthermore, input is feasible and useful in detecting cognitive impairment not revealed by screening instruments.

Impact of COVID-19 on Stroke Caseload in a Major Hyperacute Stroke Unit

Northwick Park Hospital in London, United Kingdom (UK) is one of the busiest stroke units in the country and is located in one of the areas most heavily affected by the COVID-19 pandemic in the first half of 2020. Admissions to the stroke unit and changes during the peak of COVID-19 were reviewed. Compared with the previous year, mean 96 patients were admitted with suspected stroke during April and May 2020 compared with mean 116 per month in non-COVID periods, ratio 0.82, P = 0.01. This reduction involved both strokes and mimics and was unlikely to have occurred by chance. Numbers of patients thrombolysed and of patients referred for thrombectomy decreased dramatically during this time. Mechanisms by which the COVID-19 pandemic and the March lockdown may have affected admissions to the unit are discussed. Reduced admissions to the stroke unit allowed it to contribute its resources to the care of patients with COVID-19 during the peak of admissions.

Developing a Hyperacute Stroke-Ready Nursing Workforce: a Service Improvement Initiative

Background Thrombolysis treatment varies considerably between in- and out-of-hours services. Aims This improvement initiative aimed to upskill acute stroke unit nurses as stroke thrombolysis response nurses, testing a new model of nursing in readiness for hyperacute stroke unit developments. Methods Three registered nurses were trained to a specialist competency framework. The role was tested over 28 weeks, and times to treatment milestones were measured. Thrombolysed patients from the test period were statistically compared with a matched group using a two-sample t-test in Excel. Qualitative feedback was sought from the stroke team, medical and emergency department colleagues. Findings Median out-of-hours door-to-needle time reduced from 85 to 61.5 minutes. Statistically significant differences were seen in the time to stroke unit admission (p=0.012) and swallow screen (p=0.038). Stroke and emergency department colleagues considered the role essential to out-of-hours thrombolysis treatment. Conclusions The stroke thrombolysis response nurse role reduced variation in treatment and improved timely acute stroke care. This work may inform the development of stroke nursing workforce models.

COVID-19 Stroke Apical Lung Examination Study: A Diagnostic and Prognostic Imaging Biomarker in Suspected Acute Stroke.

Diagnosis of coronavirus disease 2019 (COVID-19) relies on clinical features and reverse-transcriptase polymerase chain reaction testing, but the sensitivity is limited. Carotid CTA is a routine acute stroke investigation and includes the lung apices. We evaluated CTA as a potential COVID-19 diagnostic imaging biomarker. This was a multicenter, retrospective study (n = 225) including CTAs of patients with suspected acute stroke from 3 hyperacute stroke units (March-April 2020). We evaluated the reliability and accuracy of candidate diagnostic imaging biomarkers. Demographics, clinical features, and risk factors for COVID-19 and stroke were analyzed using univariate and multivariate statistics. Apical ground-glass opacification was present in 22.2% (50/225) of patients. Ground-glass opacification had high interrater reliability (Fleiss κ = 0.81; 95% CI, 0.68-0.95) and, compared with reverse-transcriptase polymerase chain reaction, had good diagnostic performance (sensitivity, 75% [95% CI, 56-87]; specificity, 81% [95% CI, 71-88]; OR = 11.65 [95% CI, 4.14-32.78]; P < .001) on multivariate analysis. In contrast, all other contemporaneous demographic, clinical, and imaging features available at CTA were not diagnostic for COVID-19. The presence of apical ground-glass opacification was an independent predictor of increased 30-day mortality (18.0% versus 5.7%, P = .017; hazard ratio = 3.51; 95% CI, 1.42-8.66; P = .006). We identified a simple, reliable, and accurate COVID-19 diagnostic and prognostic imaging biomarker obtained from CTA lung apices: the presence or absence of ground-glass opacification. Our findings have important implications in the management of patients presenting with suspected stroke through early identification of COVID-19 and the subsequent limitation of disease transmission.

Environmental Factors and Hyperacute Stroke Care Activity During the COVID-19 Pandemic: An Interrupted Time-Series Analysis

Background and aimsConcerns have arisen regarding patient access and delivery of acute stroke care during the COVID-19 pandemic. We investigated key population level events on activity of the three hyperacute stroke units (HASUs) within Greater Manchester and East Cheshire (GM & EC), whilst adjusting for environmental factors. MethodsWeekly stroke admission & discharge counts in the three HASUs were collected locally from Emergency Department (ED) data and Sentinel Stroke National Audit Programme core dataset prior to, and during the emergence of the COVID-19 pandemic (Jan 2020 to May 2020). Whilst adjusting for local traffic-related air pollution and ambient measurement, an interrupted time-series analysis using a segmented generalised linear model investigated key population level events on the rate of stroke team ED assessments, admissions for stroke, referrals for transient ischaemic attack (TIA), and stroke discharges. ResultsThe median total number of ED stroke assessments, admissions, TIA referrals, and discharges across the three HASU sites prior to the first UK COVID-19 death were 150, 114, 69, and 76 per week. The stable weekly trend in ED assessments and stroke admissions decreased by approximately 16% (and 21% for TIAs) between first UK hospital COVID-19 death (5th March) and the implementation of the Act-FAST campaign (6th April) where a modest 4% and 5% increase per week was observed. TIA referrals increased post Government intervention (23rd March), without fully returning to the numbers observed in January and February. Trends in discharges from stroke units appeared unaffected within the study period reported here. ConclusionDespite adjustment for environmental factors stroke activity was temporarily modified by the COVID-19 pandemic. Underlying motivations within the population are still not clear. This raises concerns that patients may have avoided urgent health care risking poorer short and long-term health outcomes.

Temporal variations in quality of acute stroke care and outcomes in London hyperacute stroke units: a mixed-methods study

Background Seven-day working in hospitals is a current priority of international health research and policy. Previous research has shown variability in delivering evidence-based clinical interventions across different times of the day and week. We aimed to identify factors influencing such variations in London hyperacute stroke units. Objectives To investigate variations in quality of acute stroke care and outcomes by day and time of admission in London hyperacute stroke units, and to identify factors influencing such variations. Design This was a prospective cohort study using anonymised patient-level data from the Sentinel Stroke National Audit Programme. Factors influencing variations in care and outcomes were studied through interview and observation data. Setting The setting was acute stroke services in London hyperacute stroke units. Participants A total of 7094 patients with a primary diagnosis of stroke took part. We interviewed hyperacute stroke unit staff (n = 76), including doctors, nurses, therapists and administrators, and 31 patients and carers. We also conducted non-participant observations of delivery of care at different times of the day and week (n = 45, ≈102 hours). Intervention Hub-and-spoke model for care of suspected acute stroke patients in London with performance standards was designed to deliver uniform access to high-quality hyperacute stroke unit care across the week. Main outcome measures Indicators of quality of acute stroke care, mortality at 3 days after admission, disability at the end of the inpatient spell and length of stay. Data sources Sentinel Stroke National Audit Programme data for all patients in London hyperacute stroke units with a primary diagnosis of stroke between 1 January and 31 December 2014, and nurse staffing data for all eight London hyperacute stroke units for the same period. Results We found no variation in quality of care by day and time of admission across the week in terms of stroke nursing assessment, brain scanning and thrombolysis in London hyperacute stroke units, nor in 3-day mortality nor disability at hospital discharge. Other quality-of-care measures significantly varied by day and time of admission. Quality of care was better if the nurse in charge was at a higher band and/or there were more nurses on duty. Staff deliver ‘front-door’ interventions consistently by taking on additional responsibilities out of hours, creating continuities between day and night, building trusting relationships and prioritising ‘front-door’ interventions. Limitations We were unable to measure long-term outcomes as our request to the Sentinel Stroke National Audit Programme, the Healthcare Quality Improvement Partnership and NHS Digital for Sentinel Stroke National Audit Programme data linked with patient mortality status was not fulfilled. Conclusions Organisational factors influence 24 hours a day, 7 days a week (24/7), provision of stroke care, creating temporal patterns of provision reflected in patient outcomes, including mortality, length of stay and functional independence. Future work Further research would help to explore 24/7 stroke systems in other contexts. We need a clearer understanding of variations by looking at absolute time intervals, rather than achievement of targets. Research is needed with longer-term mortality and modified Rankin Scale data, and a more meaningful range of outcomes. Funding This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 8, No. 34. See the NIHR Journals Library website for further project information.

Asymmetrical Bioimpedance in the Anterior Circulation for Urgent Stratification of suspected Stroke (ABACUS Stroke): study protocol for a diagnostic accuracy study

BackgroundEarly identification and treatment of stroke improve outcome. Ischaemic stroke due to large vessel occlusion (LVO) benefits from time-critical thrombectomy but this is only available in highly specialised healthcare services. Cerebral Bioimpedance Asymmetry (CBA) measurement obtained with the portable and rapid Cerebrotech Visor™ System device may be able to identify certain types of stroke including LVO. This test could be deployed pre-hospital and used to immediately direct patients to the most appropriate healthcare service for treatment. This study is evaluating the diagnostic accuracy of CBA measurements obtained from a real-world population of suspected stroke.MethodsStudy design: Prospective observational cohort study.Setting: A hyperacute stroke unit and neuroscience centre in North East England.Participants: Adults with a paramedic assigned diagnosis of suspected stroke arriving at hospital within 6 hours of symptom onset.Index Test: Cerebral Bioimpedance Asymmetry measurement performed using the Cerebrotech Visor™ System. Measurement values produce continuous data (range 0 –100); pre-defined threshold for positive state ≥ 10.Reference Standard Tests: Standard CT brain +/- CT/MR angiography, and expert clinician opinion will establish the following clinical outcomes which constitute the suspected stroke population: ischaemic stroke +/- large vessel occlusion; symptomatic severe anterior vessel stenosis; large (≥60ml) and small (<60mls) vessel intracerebral haemorrhage; transient ischaemic attack; stroke mimic conditions; prior territorial stroke.Analyses: Sensitivity, specificity, negative and positive predictive values, area under the Receiver Operating Characteristic curve for identification of i) “complex stroke” (ischaemic stroke with large vessel occlusion or symptomatic severe anterior vessel stenosis or intracerebral haemorrhage ≥60ml or prior territorial stroke) and ii) ischaemic stroke with large vessel occlusion in isolation.Sample size: 124 participantsDiscussionThe results from this study will determine how accurately CBA measurement using the Cerebrotech Visor™ System can identify key stroke types within the suspected stroke population. Acceptable diagnostic performance would be an important step forwards for access to time-critical treatments.Trial registrationRegistered with ISRCTN (identifier: ISRCTN79169844) on 06/08/2018.

Automated Continuous Electrocardiogram Monitoring Accelerates the Detection of Atrial Fibrillation after Ischemic Stroke or Transient Ischemic Attack on a Hyper Acute Stroke Unit

Background and Aim: Rapid and sensitive detection of atrial fibrillation (AF) is of paramount importance for initiation of adequate preventive therapy after stroke. Stroke Unit care includes continuous electrocardiogram monitoring (CEM) but the optimal exploitation of the recorded ECG traces is controversial. In this retrospective single-center study, we investigated whether an automated analysis of continuous electrocardiogram monitoring (ACEM), based on a software algorithm, accelerates the detection of AF in patients admitted to our Stroke Unit compared to the routine CEM. Methods: Patients with acute ischemic stroke or transient ischemic attack were consecutively enrolled. After a 12-channel ECG on admission, all patients received CEM. Additionally, in the second phase of the study the CEM traces of the patients underwent ACEM analysis using a software algorithm for AF detection. Patients with history of AF or with AF on the admission ECG were excluded. Results: The CEM (n = 208) and ACEM cohorts (n= 114) did not differ significantly regarding risk factors, duration of monitoring and length of admission. We found a higher rate of newly-detected AF in the ACEM cohort compared to the CEM cohort (15.8% versus 10.1%, P < .001). Median time to first detection of AF was shorter in the ACEM compared to the CEM cohort [10 hours (IQR 0–23) versus 46.50 hours (IQR 0–108.25), P < .001]. Conclusions: ACEM accelerates the detection of AF in patients with stroke compared with the routine CEM. Further evidences are required to confirm the increased rate of AF detected using ACEM.

Abstract TP386: National Institute of Health Stroke Scale Completion Improved in Hyperacute Stroke Unit; Quality Improvement Strategy for Implementation of the Australian Stroke Foundation 2017 Clinical Guidelines for Stroke Management

Background and Purpose: In September 2017, a new Hyperacute Stroke Unit (HASU) was opened in a metropolitan hospital with over 400 acute stroke admissions per year, offering endovascular clot retrieval (ECR) and IV thrombolysis; 185 ECR procedures completed in 2018. The HASU opening coincided with publication of the 2017 Australian Clinical Guidelines for Stroke Management. The Guidelines state stroke severity be assessed using a validated tool, such as the National Institute of Health Stroke Scale (NIHSS). A Quality Improvement workshop, March 2018, identified attendance of correct and reliable assessment for stroke severity as a service gap. Goal = Improve NIHSS completion on all stroke patients on presentation to hospital and 24hours post endovascular clot retrieval. This was to be achieved within 90 days of project implementation with the focus on nursing education; a new skill addition to the ward environment. Methods: Education workshops (August-September 18) were implemented with the goal of building knowledge, skills and confidence along with gaining NIHSS certification. All clinical and registered nurses were provided designated time to attend workshops. Workshops were also provided to Medical officers (January 2019) allocated to the Stroke team. Cognitive aids to assist with reducing variability in application of the NIHSS were created. These included NIHSS navigation aids to the electronic medical record, NIHSS app upload to mobile phones, paper based NIHSS assessment to assist the bedside nurses and ward round note templates with auto text for NIHSS completion. Data from three months pre and post implementation was collected and compared using the Australian Stroke Clinical Registry (AuSCR). All patients admitted with stroke were included in this analysis (Jan 18-April 19). Results: NIHSS completion on patient presentation increased by 12% (n=325). NIHSS completion at 24hrs for patients post ECR increased by 22% (n=163). 31 registered nurses trained; 8 medical officers trained. Conclusions: Targeted, multimodal strategies improved completion of NIHSS on presentation and particularly, 24hrs post ECR. Further implementation in the emergency department is required to gain improvements in NIHSS completion on presentation.

Quantifying the Impact of Chronic Ischemic Injury on Clinical Outcomes in Acute Stroke With Machine Learning.

Acute stroke is often superimposed on chronic damage from previous cerebrovascular events. This background will inevitably modulate the impact of acute injury on clinical outcomes to an extent that will depend on the precise anatomical pattern of damage. Previous attempts to quantify such modulation have employed only reductive models that ignore anatomical detail. The combination of automated image processing, large-scale data, and machine learning now enables us to quantify the impact of this with high-dimensional multivariate models sensitive to individual variations in the detailed anatomical pattern. We introduce and validate a new automated chronic lesion segmentation routine for use with non-contrast CT brain scans, combining non-parametric outlier-detection score, Zeta, with an unsupervised 3-dimensional maximum-flow, minimum-cut algorithm. The routine was then applied to a dataset of 1,704 stroke patient scans, obtained at their presentation to a hyper-acute stroke unit (St George's Hospital, London, UK), and used to train a support vector machine (SVM) model to predict between low (0–2) and high (3–6) pre-admission and discharge modified Rankin Scale (mRS) scores, quantifying performance by the area under the receiver operating curve (AUROC). In this single center retrospective observational study, our SVM models were able to differentiate between low (0–2) and high (3–6) pre-admission and discharge mRS scores with an AUROC of 0.77 (95% confidence interval of 0.74–0.79), and 0.76 (0.74–0.78), respectively. The chronic lesion segmentation routine achieved a mean (standard deviation) sensitivity, specificity and Dice similarity coefficient of 0.746 (0.069), 0.999 (0.001), and 0.717 (0.091), respectively. We have demonstrated that machine learning models capable of capturing the high-dimensional features of chronic injuries are able to stratify patients—at the time of presentation—by pre-admission and discharge mRS scores. Our fully automated chronic stroke lesion segmentation routine simplifies this process, and utilizes routinely collected CT head scans, thereby facilitating future large-scale studies to develop supportive clinical decision tools.

Prestroke Disability Predicts Adverse Poststroke Outcome: A Registry-Based Prospective Cohort Study of Acute Stroke.

Background and Purpose- Information on what effect disability before stroke can have on stroke outcome is lacking. We assessed prestroke disability in relation to poststroke hospital outcome. Methods- Analysis of prospectively collected data from the Sentinel Stroke National Audit Programme. A total of 1656 men (mean age ±SD =73.1±13.2 years) and 1653 women (79.3±13.0 years) were admitted to hyperacute stroke units with acute stroke in 4 major UK between 2014 and 2016. Prestroke disability, assessed by modified Rankin Scale (mRS), was tested against poststroke adverse outcomes, adjusted for age, sex, and coexisting morbidities. Results- Compared with patients with prestroke mRS score =0, individuals with prestroke mRS scores =3, 4, or 5 had greater adjusted risks of moderately severe or severe stroke on arrival (4.4% versus 16.7%; odds ratio [OR], 3.2 [95% CI, 2.3-4.6] P<0.001); urinary tract infection or pneumonia within 7 days of admission (9.6% versus 35.9%; OR, 3.7 [95% CI, 2.8-4.8] P<0.001); mortality (7.2% versus 37.1%; OR, 4.9 [95% CI, 3.7-6.5] P<0.001); requiring help with activities of daily living on discharge (12.3% versus 26.7%; OR, 3.1 [95% CI, 2.3-4.1] P<0.001); and transferred to new care home (2.4% versus 9.4%; OR, 2.1 [95% CI, 1.3-3.3] P=0.002). Patients with mRS scores =1 or 2 had intermediate risk of adverse outcomes. Overall, those with a mRS score =1 or 2 had length of stay on hyperacute stroke units extended by 5.3 days (95% CI, 2.8-7.7; P<0.001) and mRS score =3, 4 or 5 by 7.2 days (95% CI, 4.0-10.5; P<0.001). Conclusions- Individuals with evidence of prestroke disability, assessed by mRS, had significantly increased risk of poststroke adverse outcomes and longer length of stay on hyperacute stroke units and higher level of care on discharge.

What Proportion of Patients Admitted with Stroke or Transient Ischemic Attack May Be Suitable for Newer Cholesterol-Lowering Treatment?

BackgroundProtein convertase subtilisin–kexin type 9 (PCSK9) inhibitors effectively clear low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C). We evaluated stroke admissions potentially eligible for more intensive cholesterol treatment. MethodsRetrospective analysis of consecutive admissions to a hyperacute stroke unit over 5 months in 2017. Records were individually searched. Data were collected on diagnosis, risk factors, and stroke work-up. European Society of Cardiology and European Atherosclerosis Society guidelines for the management of dyslipidaemias were used for screening patients eligible for PCSK9 inhibitors. ResultsOf 650 patient admissions: 351 (54%) had acute ischemic stroke or transient ischemic attack (TIA), 80 (12%) hemorrhage, and 219 (34%) mimic syndromes. Patients with hemorrhage (n = 80), mimic syndromes (n = 219), and absent LDL-C, or non-HDL-C testing (n = 27) were subsequently excluded. 324 patients with acute ischemic stroke and TIA were further screened for PCSK9-inhibitor treatment eligibility. Forty-one (13%) patients with LDL-C greater than or equal to 1.8mmol/L (≥70 mg/dL) on maximal tolerated statin dose and with concomitant “very high vascular risk” were identified. “Very high vascular risk” was defined as a documented history of cardiovascular disease and/or peripheral arterial disease. Of 41 patients eligible for PCSK9 inhibitors, median age was 82 years (range 53-96); median vascular risk factors were 2 (range 1-5); 7 (17%) had TIA; 13 (31%) had history of preceding cerebrovascular events, 13 (31%) diabetes mellitus, 17 (42%) cardioembolic events, 9 (22%) lacunar syndrome, 11 (22%) symptomatic internal carotid artery stenosis (n = 9 were >70%), and 4 (10%) undetermined aetiology. Eighty-three percent patients eligible for PCSK9 inhibitors also had non-HDL-C values greater than or equal to 2.6 mmol/L. ConclusionsUp to 13% of unselected acute ischemic stroke or TIA patients admitted to a hyper-acute stroke unit were potentially suitable for more intensive cholesterol treatment. Our data may act as a useful guide for sample size selection in future stroke trials testing PCSK9 inhibitors.