Geographic access to acute stroke care in the United States.

Abstract

Only 3% to 5% of patients with acute ischemic stroke receive intravenous recombinant tissue-type plasminogen activator (r-tPA) and <1% receive endovascular therapy. We describe access of the US population to all facilities that actually provide intravenous r-tPA or endovascular therapy for acute ischemic stroke. We used US demographic data and intravenous r-tPA and endovascular therapy rates in the 2011 US Medicare Provider and Analysis Review data set. International Classification of Diseases-Ninth Revision codes 433.xx, 434.xx and 436 identified acute ischemic stroke cases. International Classification of Diseases-Ninth Revision code 99.10 defined intravenous r-tPA treatment and International Classification of Diseases-Ninth Revision code 39.74 defined endovascular therapy. We estimated ambulance response times using arc-Geographic Information System's network analyst and helicopter transport times using validated models. Population access to care was determined by summing the population contained within travel sheds that could reach capable hospitals within 60 and 120 minutes. Of 370,351 acute ischemic stroke primary diagnosis discharges, 14,926 (4%) received intravenous r-tPA and 1889 (0.5%) had endovascular therapy. By ground, 81% of the US population had access to intravenous-capable hospitals within 60 minutes and 56% had access to endovascular-capable hospitals. By air, 97% had access to intravenous-capable hospitals within 60 minutes and 85% had access to endovascular hospitals. Within 120 minutes, 99% of the population had access to both intravenous and endovascular hospitals. More than half of the US population has geographic access to hospitals that actually deliver acute stroke care but treatment rates remain low. These data provide a national perspective on acute stroke care and should inform the planning and optimization of stroke systems in the United States.