Modeling outcomes following redirection of emergency stroke admissions from ten local stroke units to two neuroscience centres

Introduction: Pre-hospital redirection of patients to regional stroke centres has been proposed as a strategy to maximize the opportunity for intravenous thrombolysis. We developed a model to quantify the benefit of redirection away from local services that were already providing thrombolysis.

Method: A micro-simulation on hospital and ambulance data from 1,884 consecutive emergency admissions to 10 local acute stroke units estimated the annualised effect of redirection to the nearest of two regional neuroscience centres. This reflected geographical information system calculation of new journey time, accuracy of pre-hospital stroke identification by Face Arm Speech Test and relative changes in thrombolysis eligibility, efficiency of patient selection and door-needle time between each local site and the nearest hub. A decision analytical model estimated the outcome for individual patients. All other aspects of care were considered equivalent.

Results: Based upon actual site performance, 103 additional patients would have been treated annually following redirection of 1772 FAST true positive cases and 511 stroke mimics. 392 FAST false negative cases would have been transported to a local site. If treatment decisions at neuroscience centres were modelled on maximum, median and minimum clinical benefit there would have been a change in independent (modified Rankin Score 0–2) patients of +3.0% (26 people), +1.8% (16 people) and −0.003% (0.35 people) respectively.

Conclusion: Except under the most pessimistic clinical assumptions, redirection could have improved outcomes. This reflected regional geography, higher treatment rates and/or shorter door to needle times at the neuroscience centres compared to local units.