麻豆传媒

Even under an optimistic scenario, as many as 114 million people in the U.S. would be unable to reach a comprehensive stroke center (CSC) using ground transportation within the critical treatment "golden hour," researchers estimated.

Using mathematical optimization modeling assuming the conversion of up to 20 optimally located primary stroke centers (PSCs) to CSCs per state, researcher , of the University of Pennsylvania, Philadelphia, and colleagues estimated that 63% of the population would live within a 1-hour drive and an additional 23% within a 1-hour flight of a stroke center.

Ground access would be lower in the southeastern U.S. "Stroke Belt" than in non-Stroke Belt states (32% versus 58.6%; P=0.02) and lower in states without emergency medical service routing policies (52.7% versus 68.3%; P=0.04), Mullen and colleagues wrote online in .

The modeling also suggested that in one-quarter of states, less than 60% of the population would have 60-minute air or ground access to a CSC.

"Because CSCs have not yet been proven to improve outcomes relative to other hospitals, the ideal level of population access is unknown," the researchers wrote. "Nonetheless, variability in access across states is important, because it suggests that there is a potential for significant geographic disparities in access to care."

Three-Tiered System for Stroke Treatment

In an effort to maximize early treatment of stroke patients, a three-tiered system based on the ability to care for increasingly complicated stroke patients has been proposed consisting of acute-stroke-ready hospitals, PSCs, and CSCs.

Certification of CSCs began in September of 2012, and as of May 2014 there were according to figures from the American Heart Association.

In their newly published study, Mullen and colleagues used mathematical modeling to estimate the optimal number and location of CSCs -- to which some PSCs could theoretically convert -- to maximize 1-hour access to care within the U.S.

"Up to 20 PSCs per state were selected for conversion to maximize the population with 60-minute access by ground and air," the researchers wrote. "Access was compared across states based on region and the presence of state-level emergency medical service policies preferentially routing patients to stroke centers."

There were 811 PSCs and no CSCs in the U.S. in 2010, according to figures from the , and two-thirds of Americans (65.8%) had 60-minute ground access to these centers, according to the researchers.

"After adding up to 20 optimally located CSCs per state, 63.1% of the U.S. population had 60-minute ground access and 86% had 60-minute ground/air access to a CSC," the researchers wrote.

Among the other findings:

• The number of candidate hospitals in each state ranged from 0 to 96.
• Across states, after adding 20 CSCs per state the median CSC access was 55.7% by ground (interquartile range 35.7%-71.5%) and 85.3% by ground/air (interquartile range 59.8%-92.1%).
• In the least rural areas of the U.S., 77.4% of people would have 1-hour access, compared with 25.7% in the most rural areas of the U.S.

"Even under optimal conditions, many people may not have rapid access to comprehensive stroke centers, and without oversight and population level planning, actual systems of care are likely to be substantially worse than these optimized models," Mullen noted in a written press statement.

More May Not Mean Better

An editorial published with the study noted that while increasing CSCs nationwide seems to be a proposition "with major benefit and little downside," important considerations remain.

"As noted by the authors, the overall approach to care offered at CSCs has not been shown to be superior to care offered at PSCs or other hospitals," the authors wrote.

They added that while endovascular stroke therapy, which is a key component to designation as a CSC, improves outcomes in certain acute stroke patients, it is largely restricted to patients with large vessel occlusions and severe strokes who can be treated within hours of symptom onset.

"Because of these limitations (large vessel occlusion, severe deficits, etc.) there are likely a limited number of patients who might benefit from acute endovascular stroke treatment," the researchers wrote, adding that distributing these patients across more hospitals would result in lower case volumes and potentially lower quality of care.

"I think the concern is not about reducing the quality of care at PSCs, but more about dividing the number of cases who do need CSC level of care across a wider number of CSCs," editorial co-author Adam Kelly, MD, of the University of Rochester Medical Center, Rochester, N.Y., told 麻豆传媒.

"We have data showing that higher volumes are associated with improved outcomes after acute endovascular therapy and in patients with subarachnoid hemorrhage, and having more CSCs will potentially result in smaller volumes at these CSCs."

He added that quality of care and patient outcomes must be monitored very closely as new CSCs are added so that better access does not result in lower quality of care.

Kelly said maximizing PSC access should remain a priority, and that CSC should be added in an "iterative, thoughtful manner, keeping regional needs in mind."

From the American Heart Association

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