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Diagnosis and treatment of patients with stroke in a mobile stroke unit versus in hospital: a randomised controlled trial

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Summary

Background

Only 2–5% of patients who have a stroke receive thrombolytic treatment, mainly because of delay in reaching the hospital. We aimed to assess the efficacy of a new approach of diagnosis and treatment starting at the emergency site, rather than after hospital arrival, in reducing delay in stroke therapy.

Methods

We did a randomised single-centre controlled trial to compare the time from alarm (emergency call) to therapy decision between mobile stroke unit (MSU) and hospital intervention. For inclusion in our study patients needed to be aged 18–80 years and have one or more stroke symptoms that started within the previous 2·5 h. In accordance with our week-wise randomisation plan, patients received either prehospital stroke treatment in a specialised ambulance (equipped with a CT scanner, point-of-care laboratory, and telemedicine connection) or optimised conventional hospital-based stroke treatment (control group) with a 7 day follow-up. Allocation was not masked from patients and investigators. Our primary endpoint was time from alarm to therapy decision, which was analysed with the Mann-Whitney U test. Our secondary endpoints included times from alarm to end of CT and to end of laboratory analysis, number of patients receiving intravenous thrombolysis, time from alarm to intravenous thrombolysis, and neurological outcome. We also assessed safety endpoints. This study is registered with ClinicalTrials.gov, number NCT00792220.

Findings

We stopped the trial after our planned interim analysis at 100 of 200 planned patients (53 in the prehospital stroke treatment group, 47 in the control group), because we had met our prespecified criteria for study termination. Prehospital stroke treatment reduced the median time from alarm to therapy decision substantially: 35 min (IQR 31–39) versus 76 min (63–94), p<0·0001; median difference 41 min (95% CI 36–48 min). We also detected similar gains regarding times from alarm to end of CT, and alarm to end of laboratory analysis, and to intravenous thrombolysis for eligible ischaemic stroke patients, although there was no substantial difference in number of patients who received intravenous thrombolysis or in neurological outcome. Safety endpoints seemed similar across the groups.

Interpretation

For patients with suspected stroke, treatment by the MSU substantially reduced median time from alarm to therapy decision. The MSU strategy offers a potential solution to the medical problem of the arrival of most stroke patients at the hospital too late for treatment.

Funding

Ministry of Health of the Saarland, Germany, the Werner-Jackstädt Foundation, the Else-Kröner-Fresenius Foundation, and the Rettungsstiftung Saar.

Introduction

Stroke is a main cause of death worldwide and is one of the most common causes of disability in developed countries.1 About 90% of all strokes are due to cerebral ischaemia, with the remainder due to cerebral haemorrhage.2 The only approved treatment for ischaemic stroke is recanalisation of occluded arteries by thrombolysis with alteplase within the very first hours of symptom onset.3, 4, 5 However, implementation of recanalising therapy within this narrow therapeutic window is difficult to achieve in clinical practice because neurological examination, imaging, and laboratory analyses are needed so that haemorrhagic stroke and other contraindications to thrombolysis can be excluded.4, 5 An additional time-sensitive intervention for patients with acute stroke is blood-pressure management, which has been associated with improved outcome.6, 7

Less than 15–40% of patients with acute stroke arrive at the hospital early enough to receive thrombolytic treatment,8, 9, 10 and only 2–5% of patients actually receive it.11, 12 Of those patients who do receive state-of-the-art stroke treatment, outcome is closely related to the time to treatment.13, 14, 15 Management of acute stroke must be reconfigured if we are to overcome the problem of patients arriving at the hospital too late for treatment.

As a potential solution to this problem, we first designed16 and then studied in clinical practice17 the concept of bringing guideline-adherent stroke treatment directly to the emergency site, as has previously been made possible for patients with myocardial infarction.18 This strategy is based on a specialised ambulance (mobile stroke unit; MSU)16, 17, 19 equipped with a CT scanner, a point-of-care laboratory, and a telemedicine connection to the hospital. Apart from preliminary clinical observations, no systematic analysis of the benefit of this MSU approach on stroke management has been done. We postulated that in clinical practice prehospital stroke treatment would significantly reduce the detrimental delay in receipt of state-of-the-art stroke therapy. Hence we aimed to compare the times from alarm (emergency call) to therapy decision between the MSU and the optimised standard procedure.

Section snippets

Participants

In accordance with our protocol, between November, 2008, and July, 2011, we did a randomised, parallel-group, single-centre study at the University Hospital of the Saarland, Homburg, Germany. For inclusion in our study, patients needed to be aged 18–80 years, have one or more stroke symptoms according to the modified recognition of stroke in the emergency room (ROSIER) scale20 (facial paresis, paresis of arm or leg, aphasia, or dysarthria) that had started within the previous 2·5 h, and have

Results

The figure shows the trial profile. Because we postulated that prehospital diagnostic work-up and stroke treatment would reduce the delay to therapy decision, we stopped our study when our predefined interim analysis showed the prespecified superiority (p<0·0015) in the primary endpoint.

All patients we assigned to the MSU group gave informed consent but two who would have been assigned to the control group did not. We did not lose any patients from our final analysis of our primary endpoint.

Discussion

Our main findings are that the strategy of prehospital stroke diagnosis and treatment allows therapy decisions a median of 35 min after alarm in clinical reality. Median time from symptom onset to intravenous thrombolysis was 72 min, representing a new timescale in acute stroke management.

Stroke is a medical emergency for which “time is brain”;14 however, most patients still arrive at hospital too late to receive necessary treatment.8, 9, 10 We show that MSU-based stroke management

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