Healthcare professional views about a prehospital redirection pathway for stroke thrombectomy: a multiphase deductive qualitative study.

BACKGROUND: Mechanical thrombectomy for stroke is highly effective but time-critical. Delays are common because many patients require transfer between local hospitals and regional centres. A two-stage prehospital redirection pathway consisting of a simple ambulance screen followed by regional centre assessment to select patients for direct admission could optimise access. However, implementation might be challenged by the limited number of thrombectomy providers, a lack of prehospital diagnostic tests for selecting patients and whether finite resources can accommodate longer ambulance journeys plus greater central admissions. We undertook a three-phase, multiregional, qualitative study to obtain health professional views on the acceptability and feasibility of a new pathway. METHODS: Online focus groups/semistructured interviews were undertaken designed to capture important contextual influences. We purposively sampled NHS staff in four regions of England. Anonymised interview transcripts underwent deductive thematic analysis guided by the NASSS (Non-adoption, Abandonment and Challenges to Scale-up, Spread and Sustainability, Implementation) Implementation Science framework. RESULTS: Twenty-eight staff participated in 4 focus groups, 2 group interviews and 18 individual interviews across 4 Ambulance Trusts, 5 Hospital Trusts and 3 Integrated Stroke Delivery Networks (ISDNs). Five deductive themes were identified: (1) (suspected) stroke as a condition, (2) the pathway change, (3) the value participants placed on the proposed pathway, (4) the possible impact on NHS organisations/adopter systems and (5) the wider healthcare context. Participants perceived suspected stroke as a complex scenario. Most viewed the proposed new thrombectomy pathway as beneficial but potentially challenging to implement. Organisational concerns included staff shortages, increased workflow and bed capacity. Participants also reported wider socioeconomic issues impacting on their services contributing to concerns around the future implementation. CONCLUSIONS: Positive views from health professionals were expressed about the concept of a proposed pathway while raising key content and implementation challenges and useful 'real-world' issues for consideration.

The impact of large core and late treatment trials: An update on the modelled annual thrombectomy eligibility of UK stroke patients.

INTRODUCTION: To support decisions about thrombectomy provision, we have previously estimated the annual UK population eligible for treatment as ∼10% of stroke admissions. Since then, eight further randomised trials that could alter the eligibility rate have reported in 2021-23. We updated our estimates of the eligible population from these trials and other recent studies. PATIENTS AND METHODS: An updated decision tree describing the EVT eligible population for UK stroke admissions was produced. Decision criteria were derived from the highest level of evidence available. For nodes where no specific RCT data existed, evidence was obtained from the latest systematic review(s) or the highest quality observational data. RESULTS: We estimate that 15,420 (approximately 15%) of admitted UK stroke patients are now eligible for thrombectomy, or 14,930 if advanced brain imaging using MRI/CT perfusion or collateral assessment were used in all patients. This is a 54% increase in our previous estimate in 2021. Over 50% of LAO strokes are now potentially eligible for thrombectomy. The increase in eligibility is principally due to a much larger cohort of later presenting and/or larger ischaemic core patients. CONCLUSION: Most previously independent LAO stroke patients presenting within 24 h, even in the presence of a large ischaemic core on initial non-contrast CT, should be considered for thrombectomy with use of advanced brain imaging in those presenting beyond 12 h to identify salvageable penumbral brain tissue. Treatment in most patients remains critically time-dependent and our estimates should be interpreted with this in mind.

Update on the INTEnsive ambulance-delivered blood pressure Reduction in hyper-ACute stroke Trial (INTERACT4): progress and baseline features in 2053 participants.

BACKGROUND AND AIMS: Uncertainty persists over the effects of blood pressure (BP) lowering in acute stroke. The INTEnsive ambulance-delivered blood pressure Reduction in hyper-Acute stroke Trial (INTERACT4) aims to determine efficacy and safety of hyperacute intensive BP lowering in patients with suspected acute stroke. Given concerns over the safety of this treatment in the pre-hospital setting, particularly in relation to patients with intracerebral hemorrhage, we provide an update on progress of the study and profile of participants to date. METHODS: INTERACT4 is an ongoing multicentre, ambulance-delivered, randomized, open-label, blinded endpoint trial of pre-hospital BP lowering in patients with suspected acute stroke and elevated BP in China. Patients are randomized via a mobile phone digital system to intensive (target systolic BP [SBP] <140mmHg within 30 min) or guideline-recommended BP management. Primary outcome is an ordinal analysis of the full range of scores on the modified Rankin scale scores at 90 days. RESULTS: Between March 2020 and April 2023, 2053 patients (mean age 70 years, female 39%) were recruited with a mean BP 178/98 mmHg in whom 45% have a diagnosis of primary intracerebral hemorrhage upon arrival at hospital. At the time of presentation to hospital, the mean SBP was 160 and 170mmHg in the intensive and control groups (Δ10 mmHg), respectively. The independent data and safety monitoring board has not identified any safety concerns and recommended continuation of the trial. The sample size was reduced from 3116 to 2320 after meetings in August 2022 as the stroke mimic rate was persistently lower than initially estimated (6% vs 30%). The study is expected to be completed in late 2023 and the results announced in May 2024. CONCLUSIONS: INTERACT4 is on track to provide reliable evidence of the effectiveness of ambulance-delivered intensive BP lowering in patients with suspected acute stroke. TRIAL REGISTRATION: ClinicalTrials.gov NCT03790800 ; registered on 2 January 2019. Chinese Trial Registry ChCTR1900020534 , registered on 7 January 2019.

Is bureaucracy being busted in research ethics and governance for health services research in the UK? Experiences and perspectives reported by stakeholders through an online survey.

BACKGROUND: It has long been noted that the chain from identification of need (research gap) to impact in the real world is both long and tortuous. This study aimed to contribute evidence about research ethics and governance arrangements and processes in the UK with a focus on: what works well; problems; impacts on delivery; and potential improvements. METHODS: Online questionnaire widely distributed 20th May 2021, with request to forward to other interested parties. The survey closed on 18th June 2021. Questionnaire included closed and open questions related to demographics, role, study objectives. RESULTS: Responses were received from 252 respondents, 68% based in universities 25% in the NHS. Research methods used by respondents included interviews/focus groups (64%); surveys/questionnaires (63%); and experimental/quasi experimental (57%). Respondents reported that participants in the research they conducted most commonly included: patients (91%); NHS staff (64%) and public (50%). Aspects of research ethics and governance reported to work well were: online centralised systems; confidence in rigorous, respected systems; and helpful staff. Problems with workload, frustration and delays were reported, related to overly bureaucratic, unclear, repetitive, inflexible and inconsistent processes. Disproportionality of requirements for low-risk studies was raised across all areas, with systems reported to be risk averse, defensive and taking little account of the risks associated with delaying or deterring research. Some requirements were reported to have unintended effects on inclusion and diversity, particularly impacting Patient and Public Involvement (PPI) and engagement processes. Existing processes and requirements were reported to cause stress and demoralisation, particularly as many researchers are employed on fixed term contracts. High negative impacts on research delivery were reported, in terms of timescales for completing studies, discouraging research particularly for clinicians and students, quality of outputs and costs. Suggested improvements related to system level changes / overall approach and specific refinements to existing processes. CONCLUSIONS: Consultation with those involved in Health Services Research in the UK revealed a picture of overwhelming and increasing bureaucracy, delays, costs and demoralisation related to gaining the approvals necessary to conduct research in the NHS. Suggestions for improvement across all three areas focused on reducing duplication and unnecessary paperwork/form filling and reaching a better balance between risks of harm through research and harms which occur because research to inform practice is delayed or deterred.

Optimizing lipid management-impact of the COVID 19 pandemic upon cardiovascular risk in England.

BACKGROUND: We sought to understand the impact of the COVID-19 pandemic on lipid-lowering therapy prescribing as a potential cause of the excess cardiovascular mortality seen post-pandemic in England. We examined temporal changes over 3 years in the prescribing of high-intensity and non-high-intensity statin therapy and ezetimibe. SOURCES OF DATA: We utilized data available via the National Health Service (NHS) Business Services Authority (NHSBSA) Information Services Data Warehouse, extracting 3 monthly data from October 2018 to December 2021 on high- and low-intensity statin and ezetimibe prescribing, (commencement, cessation or continuation) through each time period of study and those before, and after, the period of interest. AREAS OF AGREEMENT: Optimizing lipid management is a key component of the NHS Long Term Plan ambition to reduce deaths from cardiovascular disease, stroke and dementia. AREAS OF CONTROVERSY: The COVID-19 pandemic and associated lockdown have seen a significant reduction in prescribing of lipid-lowering therapies. If cardiovascular risk is not to worsen in the forthcoming years, urgent action is needed to ensure that the impact of the pandemic upon optimization of cholesterol and the historical undertreatment of cholesterol is reversed and improved. AREAS TIMELY FOR DEVELOPING RESEARCH: Prescription data available via NHSBSA can support our understanding of the implications of policy and behaviour and highlight the impact of guidelines in practise. GROWING POINTS: Understanding the impact of the COVID-19 pandemic upon cholesterol management and the opportunities for newer lipid-lowering therapies delivered using a population health approach have the potential to enhance lipid-lowering and improve cardiovascular mortality and morbidity and reduce health inequalities.

National PReCePT Programme: a before-and-after evaluation of the implementation of a national quality improvement programme to increase the uptake of magnesium sulfate in preterm deliveries.

OBJECTIVE: To evaluate the effectiveness and cost-effectiveness of the National PReCePT Programme (NPP) in increasing use of magnesium sulfate (MgSO4) in preterm births. DESIGN: Before-and-after study. SETTING: Maternity units (N=137) within NHS England and the Academic Health Science Network (AHSN) in 2018. PARTICIPANTS: Babies born ≤30 weeks' gestation admitted to neonatal units in England. INTERVENTIONS: The NPP was a quality improvement (QI) intervention including the PReCePT (Preventing Cerebral Palsy in Pre Term labour) QI toolkit and materials (preterm labour proforma, staff training presentations, parent leaflet, posters for the unit and learning log), regional AHSN-level support, and up to 90 hours funded backfill for a midwife 'champion' to lead implementation. MAIN OUTCOME MEASURES: MgSO4 uptake post implementation was compared with pre-NPP implementation uptake. Implementation and lifetime costs were estimated. RESULTS: Compared with pre-implementation estimates, the average MgSO4 uptake for babies born ≤30 weeks' gestation, in 137 maternity units in England, increased by 6.3 percentage points (95% CI 2.6 to 10.0 percentage points) to 83.1% post implementation, accounting for unit size, maternal, baby and maternity unit factors, time trends, and AHSN. Further adjustment for early/late initiation of NPP activities increased the estimate to 9.5 percentage points (95% CI 4.3 to 14.7 percentage points). From a societal and lifetime perspective, the health gains and cost savings associated with the NPP effectiveness generated a net monetary benefit of £866 per preterm baby and the probability of the NPP being cost-effective was greater than 95%. CONCLUSION: This national QI programme was effective and cost-effective. National programmes delivered via coordinated regional clinical networks can accelerate uptake of evidence-based therapies in perinatal care.

Artificial intelligence-based decision support software to improve the efficacy of acute stroke pathway in the NHS: an observational study.

Introduction: In a drip-and-ship model for endovascular thrombectomy (EVT), early identification of large vessel occlusion (LVO) and timely referral to a comprehensive center (CSC) are crucial when patients are admitted to an acute stroke center (ASC). Several artificial intelligence (AI) decision-aid tools are increasingly being used to facilitate the rapid identification of LVO. This retrospective cohort study aimed to evaluate the impact of deploying e-Stroke AI decision support software in the hyperacute stroke pathway on process metrics and patient outcomes at an ASC in the United Kingdom. Methods: Except for the deployment of e-Stroke on 01 March 2020, there were no significant changes made to the stroke pathway at the ASC. The data were obtained from a prospective stroke registry between 01 January 2019 and 31 March 2021. The outcomes were compared between the 14 months before and 12 months after the deployment of AI (pre-e-Stroke cohort vs. post-e-Stroke cohort) on 01 March 2020. Time window analyses were performed using Welch's t-test. Cochran-Mantel-Haenszel test was used to compare changes in disability at 3 months assessed by modified Rankin Score (mRS) ordinal shift analysis, and Fisher's exact test was used for dichotomised mRS analysis. Results: In the pre-e-Stroke cohort, 19 of 22 patients referred received EVT. In the post-e-Stroke cohort, 21 of the 25 patients referred were treated. The mean door-in-door-out (DIDO) and door-to-referral times in pre-e-Stroke vs. post-e-Stroke cohorts were 141 vs. 79 min (difference 62 min, 95% CI 96.9-26.8 min, p < 0.001) and 71 vs. 44 min (difference 27 min, 95% CI 47.4-5.4 min, p = 0.01), respectively. The adjusted odds ratio (age and NIHSS) for mRS ordinal shift analysis at 3 months was 3.14 (95% CI 0.99-10.51, p = 0.06) and the dichotomized mRS 0-2 at 3 months was 16% vs. 48% (p = 0.04) in the pre- vs. post-e-Stroke cohorts, respectively. Conclusion: In this single-center study in the United Kingdom, the DIDO time significantly decreased since the introduction of e-Stroke decision support software into an ASC hyperacute stroke pathway. The reduction in door-in to referral time indicates faster image interpretation and referral for EVT. There was an indication of an increased proportion of patients regaining independent function after EVT. However, this should be interpreted with caution given the small sample size. Larger, prospective studies and further systematic real-world evaluation are needed to demonstrate the widespread generalisability of these findings.

Association of Blood Pressure Lowering Intensity With White Matter Network Integrity in Patients With Cerebral Small Vessel Disease.

BACKGROUND AND OBJECTIVES: Diffusion tensor imaging (DTI) networks integrate damage from a variety of pathologic processes in cerebral small vessel disease (SVD) and may be a sensitive marker to detect treatment effects. We determined whether brain network analysis could detect treatment effects in the PRESERVE trial data set, in which intensive vs standard blood pressure (BP) lowering was compared. The primary end point of DTI had not shown treatment differences. METHODS: Participants with lacunar stroke were randomized to standard (systolic 130-140 mm Hg) or intensive (systolic ≤ 125 mm Hg) BP lowering and followed for 2 years with MRI at baseline and at 2 years. Graph theory-based metrics were derived from DTI data to produce a measure of network integrity weighted global efficiency and compared with individual MRI markers of DTI, brain volume, and white matter hyperintensities. RESULTS: Data were available in 82 subjects: standard n = 40 (mean age 66.3 ± 1.5 years) and intensive n = 42 (mean age 69.6 ± 1.0 years). The mean (SD) systolic BP was reduced by 13(14) and 23(23) mm Hg in the standard and intensive groups, respectively (p < 0.001 between groups). Significant differences in diffusion network metrics were found, with improved network integrity (weighted global efficiency, p = 0.002) seen with intensive BP lowering. In contrast, there were no significant differences in individual MRI markers including DTI histogram metrics, brain volume, or white matter hyperintensities. DISCUSSION: Brain network analysis may be a sensitive surrogate marker in trials in SVD. This work suggests that measures of brain network efficiency may be more sensitive to the effects of BP control treatment than conventional DTI metrics. TRIAL REGISTRATION INFORMATION: The trial is registered with the ISRCTN Registry (ISRCTN37694103; doi.org/10.1186/ISRCTN37694103) and the NIHR Clinical Research Network (CRN 10962; public-odp.nihr.ac.uk/QvAJAXZfc/opendoc.htm?document=crncc_users%5Cfind%20a%20clinical%20research%20study.qvw&lang=en-US&host=QVS%40crn-prod-odp-pu&anonymous=true). CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that intensive BP lowering in patients with SVD results in improved brain network function when assessed by DTI-based brain network metrics.

Cost-Effectiveness of Antihypertensive Deprescribing in Primary Care: a Markov Modelling Study Using Data From the OPTiMISE Trial.

BACKGROUND: Deprescribing of antihypertensive medications for older patients with normal blood pressure is recommended by some clinical guidelines, where the potential harms of treatment may outweigh the benefits. This study aimed to assess the cost-effectiveness of this approach. METHODS: A Markov patient-level simulation was undertaken to model the effect of withdrawing one antihypertensive compared with usual care, over a life-time horizon. Model population characteristics were estimated using data from the OPTiMISE antihypertensive deprescribing trial, and the effects of blood pressure changes on outcomes were derived from the literature. Health-related quality of life was modeled in Quality-Adjusted Life Years (QALYs) and presented as costs per QALY gained. RESULTS: In the base-case analysis, medication reduction resulted in lower costs than usual care (mean difference £185), but also lower QALYs (mean difference 0.062) per patient over a life-time horizon. Usual care was cost-effective at £2975 per QALY gained (more costly, but more effective). Medication reduction resulted more heart failure and stroke/TIA events but fewer adverse events. Medication reduction may be the preferred strategy at a willingness-to-pay of £20 000/QALY, where the baseline absolute risk of serious drug-related adverse events was ≥7.7% a year (compared with 1.7% in the base-case). CONCLUSIONS: Although there was uncertainty around many of the assumptions underpinning this model, these findings suggest that antihypertensive medication reduction should not be attempted in many older patients with controlled systolic blood pressure. For populations at high risk of adverse effects, deprescribing may be beneficial, but a targeted approach would be required in routine practice.

National implementation of reperfusion for acute ischaemic stroke in England: How should services be configured? A modelling study.

Objectives: To guide policy when planning thrombolysis (IVT) and thrombectomy (MT) services for acute stroke in England, focussing on the choice between 'mothership' (direct conveyance to an MT centre) and 'drip-and-ship' (secondary transfer) provision and the impact of bypassing local acute stroke centres. Design: Outcome-based modelling study. Setting: 107 acute stroke centres in England, 24 of which provide IVT and MT (IVT/MT centres) and 83 provide only IVT (IVT-only units). Participants: 242,874 emergency admissions with acute stroke over 3 years (2015-2017). Intervention: Reperfusion delivered by drip-and-ship, mothership or 'hybrid' models; impact of additional travel time to directly access an IVT/MT centre by bypassing a more local IVT-only unit; effect of pre-hospital selection for large artery occlusion (LAO). Main outcome measures: Population benefit from reperfusion, time to IVT and MT, admission numbers to IVT-only units and IVT/MT centres. Results: Without pre-hospital selection for LAO, 94% of the population of England live in areas where the greatest clinical benefit, assuming unknown patient status, accrues from direct conveyance to an IVT/MT centre. However, this policy produces unsustainable admission numbers at these centres, with 78 out of 83 IVT-only units receiving fewer than 300 admissions per year (compared to 3 with drip-and-ship). Implementing a maximum permitted additional travel time to bypass an IVT-only unit, using a pre-hospital test for LAO, and selecting patients based on stroke onset time, all help to mitigate the destabilising effect but there is still some significant disruption to admission numbers, and improved selection of patients suitable for MT selectively reduces the number of patients who would receive IVT at IVT-only centres, challenging the sustainability of IVT expertise in IVT-only centres. Conclusions: Implementation of reperfusion for acute stroke based solely on achieving the maximum population benefit potentially leads to destabilisation of the emergency stroke care system. Careful planning is required to create a sustainable system, and modelling may be used to help planners maximise benefit from reperfusion while creating a sustainable emergency stroke care system.

Cost-effectiveness of an enhanced Paramedic Acute Stroke Treatment Assessment (PASTA) during emergency stroke care: Economic results from a pragmatic cluster randomized trial.

BACKGROUND: The Paramedic Acute Stroke Treatment Assessment (PASTA) trial evaluated an enhanced emergency care pathway which aimed to facilitate thrombolysis in hospital. A pre-planned health economic evaluation was included. The main results showed no statistical evidence of a difference in either thrombolysis volume (primary outcome) or 90-day dependency. However, counter-intuitive findings were observed with the intervention group showing fewer thrombolysis treatments but less dependency. AIMS: Cost-effectiveness of the PASTA intervention was examined relative to standard care. METHODS: A within trial cost-utility analysis estimated mean costs and quality-adjusted life years over 90 days' time horizon. Costs were derived from resource utilization data for individual trial participants. Quality-adjusted life years were calculated by mapping modified Rankin scale scores to EQ-5D-3L utility tariffs. A post-hoc subgroup analysis examined cost-effectiveness when trial hospitals were divided into compliant and non-compliant with recommendations for a stroke specialist thrombolysis rota. RESULTS: The trial enrolled 1214 patients: 500 PASTA and 714 standard care. There was no evidence of a quality-adjusted life year difference between groups [0·007 (95% CI: -0·003 to 0·018)] but costs were lower in the PASTA group [-£1473 (95% CI: -£2736 to -£219)]. There was over 97.5% chance that the PASTA pathway would be considered cost-effective. There was no evidence of a difference in costs at seven thrombolysis rota compliant hospitals but costs at eight non-complaint hospitals costs were lower in PASTA with more dominant cost-effectiveness. CONCLUSIONS: Analyses indicate that the PASTA pathway may be considered cost-effective, particularly if deployed in areas where stroke specialist availability is limited.Trial Registration: ISRCTN12418919 www.isrctn.com/ISRCTN12418919.

INTEnsive ambulance-delivered blood pressure Reduction in hyper-ACute stroke Trial (INTERACT4): study protocol for a randomized controlled trial.

BACKGROUND: Early pre-hospital initiation of blood pressure (BP) lowering could improve outcomes for patients with acute stroke, by reducing hematoma expansion in intracerebral hemorrhage (ICH), and time to reperfusion treatment and risk of intracranial hemorrhage in ischemic stroke (IS). We present the design of the fourth INTEnsive ambulance-delivered blood pressure Reduction in hyper-ACute stroke Trial (INTERACT4). METHODS: A multi-center, ambulance-delivered, prospective, randomized, open-label, blinded endpoint (PROBE) assessed trial of pre-hospital BP lowering in 3116 hypertensive patients with suspected acute stroke at 50+ sites in China. Patients are randomized through a mobile phone digital system to intensive BP lowering to a target systolic BP of < 140 mmHg within 30 min, or guideline-recommended BP management according to local protocols. After the collection of in-hospital clinical and management data and 7-day outcomes, trained blinded assessors conduct telephone or face-to-face assessments of physical function and health-related quality of life in participants at 90 days. The primary outcome is the physical function on the modified Rankin scale at 90 days, analyzed as an ordinal outcome with 7 categories. The sample size was estimated to provide 90% power (α = 0.05) to detect a 22% reduction in the odds of a worse functional outcome using ordinal logistic regression. DISCUSSION: INTERACT4 is a pragmatic clinical trial to provide reliable evidence on the effectiveness and safety of ambulance-delivered hyperacute BP lowering in patients with suspected acute stroke. TRIAL REGISTRATION: ClinicalTrials.gov NCT03790800. Registered on 2 January 2019; Chinese Trial Registry ChiCTR1900020534. Registered on 7 January 2019. All items can be found in this protocol paper.

Blood Pressure Changes Following Antihypertensive Medication Reduction, by Drug Class and Dose Chosen for Withdrawal: Exploratory Analysis of Data From the OPTiMISE Trial.

Aims: Deprescribing of antihypertensive drugs is recommended for some older patients with polypharmacy, but there is little evidence to inform which drug (or dose) should be withdrawn. This study used data from the OPTiMISE trial to examine whether short-term outcomes of deprescribing vary by drug class and dose of medication withdrawn. Methods: The OPTiMISE trial included patients aged ≥80 years with controlled systolic blood pressure (SBP; <150 mmHg), receiving ≥2 antihypertensive medications. This study compared SBP control, mean change in SBP and frequency of adverse events after 12 weeks in participants stopping one medication vs. usual care, by drug class and equivalent dose of medication withdrawn. Equivalent dose was determined according to the defined daily dose (DDD) of each medication type. Drugs prescribed below the DDD were classed as low dose and those prescribed at ≥DDD were described as higher dose. Outcomes were examined by generalized linear mixed effects models. Results: A total of 569 participants were randomized, aged 85 ± 3 years with controlled blood pressure (mean 130/69 mmHg). Within patients prescribed calcium channel blockers, higher dose medications were more commonly selected for withdrawal (90 vs. 10%). In those prescribed beta-blockers, low dose medications were more commonly chosen (87 vs. 13%). Withdrawal of calcium channel blockers was associated with an increase in SBP (5 mmHg, 95%CI 0-10 mmHg) and reduced SBP control (adjusted RR 0.89, 95%CI 0.80-0.998) compared to usual care. In contrast, withdrawal of beta-blockers was associated with no change in SBP (-4 mmHg, 95%CI -10 to 2 mmHg) and no difference in SBP control (adjusted RR 1.15, 95%CI 0.96-1.37). Similarly, withdrawal of higher dose medications was associated with an increase in SBP but no change in BP control. Withdrawal of lower dose medications was not associated with a difference in SBP or SBP control. There was no association between withdrawal of specific drug classes and adverse events. Conclusion: These exploratory data suggest withdrawal of higher dose calcium channel blockers should be avoided if the goal is to maintain BP control. However, low dose beta-blockers may be removed with little impact on blood pressure over 12-weeks of follow-up. Larger studies are needed to confirm these associations.

PRESERVE: Randomized Trial of Intensive Versus Standard Blood Pressure Control in Small Vessel Disease.

[Figure: see text].

Purines for Rapid Identification of Stroke Mimics (PRISM): study protocol for a diagnostic accuracy study.

BACKGROUND: Rapid treatment of stroke improves outcomes, but accurate early recognition can be challenging. Between 20 and 40% of patients suspected to have stroke by ambulance and emergency department staff later receive a non-stroke 'mimic' diagnosis after stroke specialist investigation. This early diagnostic uncertainty results in displacement of mimic patients from more appropriate services, inappropriate demands on stroke specialist resources and delayed access to specialist therapies for stroke patients. Blood purine concentrations rise rapidly during hypoxic tissue injury, which is a key mechanism of damage during acute stroke but is not typical in mimic conditions. A portable point of care fingerprick test has been developed to measure blood purine concentration which could be used to triage patients experiencing suspected stroke symptoms into those likely to have a non-stroke mimic condition and those likely to have true stroke. This study is evaluating test performance for identification of stroke mimic conditions. METHODS: Design: prospective observational cohort study Setting: regional UK ambulance and acute stroke services Participants: a convenience series of two populations will be tested: adults with a label of suspected stroke assigned (and tested) by attending ambulance personnel and adults with a label of suspected stroke assigned at hospital (who have not been tested by ambulance staff). INDEX TEST: SMARTChip Purine assay Reference standard tests: expert clinician opinion informed by brain imaging and/or other investigations will assign the following diagnoses which constitute the suspected stroke population: ischaemic stroke, haemorrhagic stroke, TIA and stroke mimic conditions. SAMPLE SIZE: ambulance population (powered for mimic sensitivity) 935 participants; hospital population (powered for mimic specificity) 377 participants. ANALYSES: area under the receiver operating curve (ROC) and optimal sensitivity, specificity, and negative and positive predictive values for identification of mimic conditions. Optimal threshold for the ambulance population will maximise sensitivity, minimum 80%, and aim to keep specificity above 70%. Optimal threshold for the hospital population will maximise specificity, minimum 80%, and aim to keep sensitivity above 70%. DISCUSSION: The results from this study will determine how accurately the SMARTChip purine assay test can identify stroke mimic conditions within the suspected stroke population. If acceptable performance is confirmed, deployment of the test in ambulances or emergency departments could enable more appropriate direction of patients to stroke or non-stroke services. TRIAL REGISTRATION: Registered with ISRCTN (identifier: ISRCTN22323981) on 13/02/2019 http://www.isrctn.com/ISRCTN22323981.

Updating estimates of the number of UK stroke patients eligible for endovascular thrombectomy: incorporating recent evidence to facilitate service planning.

Introduction: Endovascular thrombectomy (EVT) is a highly effective treatment for acute ischaemic stroke due to large arterial occlusion (LAO). To support decisions about service provision, we previously estimated the annual UK population eligible for EVT as ∼10% of stroke admissions. Since then, several trials have produced evidence that could alter these figures. We update our estimates considering information from studies and trials reporting 2018-2021 on incidence, presentation time and stroke severity and consider the possible impact of predicted demographic changes in the next 10-20 years. Patients and Methods: We produce an updated decision tree describing the EVT eligible population for UK stroke admissions. One-way sensitivity analyses (using upper and lower confidence intervals for estimates at each branch of our decision tree) were used to identify where further research evidence is necessary to increase certainty around estimates for numbers of EVT eligible patients. Results: The updated estimate for the number of UK stroke patients eligible for EVT annually was between 10,020 (no advanced imaging in early presenting patients) and 9,580 (advanced imaging in all early presenting patients), which compared with our estimates in 2017 is a minimal reduction. One-way sensitivity analyses established that enhanced evidence about eligibility for milder strokes, ASPECTS scores and pre-stroke disability are offset by evidence regarding a lower incidence of LAO. Importantly, predicted increases in life expectancy by 2040 may increase thrombectomy need by 40%. Discussion: Information from additional randomised trials published during 2018-2020 with updated estimates of LAO prevalence had a minimal impact on overall estimates of stroke patients eligible for EVT in the UK. Ongoing research into the benefits of EVT for patients with mild stroke or European Stroke Journal For Peer Review lower ASPECTS scores has the potential to increase the estimates of the eligible population; future need for EVT will increase with the ageing population. Conclusion: Our updated analyses show overall numbers eligible little changed, but evidence from ongoing trials and demographic changes have the potential to increase the need for EVT significantly.