Geographic Access to Acute Stroke Care in the United States

Study Questions:

What is the access of the US population to all facilities that actually provide intravenous recombinant tissue-type plasminogen activator (r-tPA) or endovascular therapy for acute ischemic stroke?

Methods:

The investigators 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. They 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.

Results:

Of 370,351 acute ischemic stroke primary diagnosis discharges, 14,926 (4%) received intravenous r-tPA and 1,889 (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.

Conclusions:

The authors concluded that more than half of the US population has geographic access to hospitals that actually deliver acute stroke care, but treatment rates remain low.

Perspective:

This study reports that most of the US population has geographic access to hospitals capable of delivering intravenous r-tPA by ground or air, whereas about half of the country has 60-minute ground access and 85% has 60-minute air access to endovascular therapy. Within 120 minutes, close to 100% of the US population has access to both intravenous and endovascular therapy by ground or air. Despite this, treatment rates were extremely low, with intravenous r-tPA administered to 4% and endovascular therapy to 0.5% of all discharged patients with acute ischemic stroke. These data provide a national perspective on acute stroke care, and should help inform the planning and optimization of stroke systems in the United States.

Keywords: Thrombolytic Therapy, Stroke, International Classification of Diseases, Demography, Geographic Information Systems, Tissue Plasminogen Activator, Medicare, Reaction Time


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