How close Americans live to hospitals that can perform angioplasty

Mar 9 2006

University of Michigan and Yale analysis shows that within 60 minutes, 80 percent of Americans could reach a hospital that can do emergency angioplasty.

In a heart attack, every minute counts. But should patients spend a few more of those minutes getting to a hospital that can provide the most advanced treatment, rather than just the closest hospital?

That question is at the heart of a current debate among heart specialists: whether to make heart attack care more like trauma care, with ambulance crews taking certain patients to specialized hospitals that can perform emergency heart procedures, rather than stopping at the closest hospital.

A new study looks at a crucial issue in that debate: how close Americans live to hospitals that can perform angioplasty, which is considered the best treatment for the form of heart attack called STEMI, if it's done quickly. Only a fraction of American hospitals perform angioplasties, which re-open blocked blood vessels in the heart and can be done electively to prevent a heart attack or urgently to treat one.

The new research shows that nearly 80 percent of Americans live within an hour's ambulance trip of an angioplasty-performing hospital. The University of Michigan and Yale University research team made the finding by combining and analyzing census data, hospital locations, driving distances and estimated driving times,

The researchers also found that the closest hospital to about 58 percent of Americans doesn't do angioplasty. But the extra drive time to an angioplasty hospital would be less than 30 minutes for most of them, though many patients in rural areas would have farther to go.

The research will be published March 8 in the journal Circulation, and will also be presented March 13 at the annual meeting of the American College of Cardiology.

"There are many more issues involved in regionalizing heart attack care, with proximity to specialized hospitals being necessary, but not sufficient, for making such a system feasible," says lead author Brahmajee Nallamothu, M.D., MPH. an assistant professor of internal medicine at the U-M Medical School, researcher at the VA Ann Arbor Healthcare System and member of the U-M Cardiovascular Center.

"This study puts in perspective what it would mean for patients to be diverted from the closest hospital to one that performs angioplasty." Says Harlan Krumholz, M.D., senior author and professor at the Yale School of Medicine. "For some patients the difference in time is trivial, for others it may add a potentially dangerous delay to their treatment. It suggests that a national policy needs to take into account local geography."

Adds co-author Eric Bates, M.D., a U-M professor of cardiovascular medicine who has studied emergency heart attack care for years, "This analysis is a first step. It shows that the majority of patients don't have geographic limitations that would obstruct the concept of regionalization, but it doesn't address implementation and economic issues."

One of the major issues in the regionalization debate is the ability of ambulance crews to distinguish STEMI heart attacks from other problems using portable electrocardiogram equipment, since only STEMI patients have been shown to derive more benefit from emergency angioplasty than from fibrinolytic (clot-busting) drugs that can be given at most hospitals.

Research by the new paper's authors and others also continues to show that emergency angioplasty holds the most benefit for patients when it's performed by experienced doctors at hospitals where it is the "default" STEMI treatment and when it can be performed in a timely way.

For these reasons and more, Nallamothu notes that the regionalization of heart attack care will probably have to happen on a local and state basis, rather than nationally. Already, he says, several cities such as Boston and states such as Maryland have started to implement new protocols for ambulances and hospitals that allow quick diagnosis of STEMI and immediate transport of STEMI patients to hospitals that can perform emergency angioplasty.

The new study is based on data from the 2000 U.S. Census broken down by individual tracts, the American Hospital Association's database of hospitals' locations and the services they provide, Medicare data on angioplasty billing by hospitals, and driving times, distances and road routes derived from commercial geographical mapping software. The researchers added in time for the dispatching of an ambulance and the assessment and loading of a patient at the scene by the emergency medical personnel.

In all, 1,176 hospitals provided angioplasty, about 25 percent of all acute-care hospitals at the time. The number and percentage have almost certainly grown since 2001, as more states allow hospitals to perform angioplasty even if they don't have open-heart surgery capability in case of a complication.

The median driving time to an angioplasty hospital was calculated to be 11.3 minutes, or a distance of 7.9 miles. Driving times and distances were calculated using road routes, not "as the crow flies."

The researchers also calculated the "bypass delay" - the additional minutes an ambulance would have to drive to get to an angioplasty hospital if it wasn't the closest hospital. The median was 10.6 minutes, and 9.7 miles. A total of 73.8 percent of adults whose ambulances would have to bypass another hospital to get to an angioplasty hospital would be able to get there within 30 minutes, and 90 percent would get there within 60 minutes of additional driving time.

While 79 percent of American adults lived within a 60 minute ambulance trip of an angioplasty hospital, there was tremendous variation across the nation. In the mid-Atlantic states, New England, and West Coast states, more than 82 percent of adults were within an hour of such a hospital, while in the plains states and desert Southwest, the percentage was in the 60s. No matter what state they lived in, only 47 percent of rural adults were within an hour's drive of an angioplasty hospital. And rural adults also faced longer "bypass delays" than adults in suburban and urban areas.