Where you live may determine if you survive a stroke

Americans' odds of receiving a drug that can halt strokes in progress may vary widely depending on their ZIP codes, a new study finds.

Experts said the findings, reported in the July issue of the journal Stroke, help verify what everyone has suspected: There are disparities in emergency stroke care across the United States, specifically in the use of a clot-busting drug called tissue plasminogen activator, or tPA.

And the magnitude of the disparities was "striking," said senior researcher Dr. James Burke, of the University of Michigan in Ann Arbor.

In 20 percent of hospital markets, not a single stroke patient received tPA over four years, Burke's team found. In others, up to 14 percent of stroke patients received the drug.

The big question is: Why? "We really don't know what's driving this," Burke said.

The hospital markets that most often gave tPA were scattered across the country, in urban and rural areas, the investigators found. And they included both regions with relatively high and relatively low rates of stroke.

Whatever the reasons, Burke said, there is clearly a need to close the regional gaps in tPA use.

"We have a treatment that works," he said. "We need to figure out how to best get it to the patients who can benefit."

Most strokes are caused by a blood clot in the arteries supplying the brain. If tPA is given in time, it can break up the clot and limit brain damage from the stroke. But that's not as simple as it sounds.

First, tPA has to be given within three hours of the initial stroke symptoms. So people have to quickly recognize those symptoms, then get to the emergency room.

From there, doctors have to be sure the stroke is caused by a blood clot, which requires a CT scan. (Some strokes are caused by bleeding in the brain, and giving tPA could worsen the situation.)

Most U.S. hospitals have the technical capability to give tPA, Burke said. What varies, he added, is their experience and comfort with using the drug.

Neurologist Dr. Koto Ishida directs the NYU Langone Comprehensive Stroke Care Center in New York City. She agreed that experience and comfort level are key.

"This drug does have risks, and it's definitely not right for all stroke patients," said Ishida, who was not involved with the study.

Those risks include bleeding in the brain, which happens about 6 percent of the time, according to the American Academy of Neurology. Plus, certain people -- such as those with uncontrolled high blood pressure -- should not receive tPA.

Ishida also pointed to the relative complexity of emergency stroke care: It's a "team effort," she said, involving paramedics, ER doctors, nurses, a neurologist, radiologist and a pharmacist to mix the tPA.

At a smaller hospital, those specialists might not be readily available all the time, Burke suggested.

And in general, Ishida said, hospitals that see more stroke patients -- particularly those certified as a "primary stroke center" -- will have a more efficient process in place for getting patients the right treatment.

Still, in this study, living near a primary stroke center made only a minor difference in the likelihood of receiving tPA, Burke said.

Other research has shown that delayed hospital arrival is a major reason that stroke sufferers cannot receive tPA.

That's why people need to know the signs of stroke, both Burke and Ishida said. Symptoms include sudden weakness or numbness in the face, an arm or a leg; slurred speech; blurry vision; dizziness or trouble with balance and coordination.

"It's not like a heart attack, where pain will often drive people to call 911," Ishida said. "With stroke, people often wait to see if the symptoms go away. But you can't predict whether you'll get better. Don't wait to call 911."

The current findings are based on more than 840,000 Medicare patients who suffered a stroke between 2007 and 2010. Each lived within one of 3,436 U.S. hospital markets.

In 20 percent of those hospital markets, no stroke patients received tPA. In the top-20 percent, tPA was given to 9 percent of patients, on average. Some markets -- in states spanning from California to Iowa, Minnesota, Pennsylvania and North Carolina -- were in the range of 10 to 14 percent.

According to Burke, it will be important to understand why some hospital regions have high rates of tPA use and, if possible, repeat their success elsewhere.

If all hospital markets could reach the 14-percent mark, that would mean an additional 93,000 patients getting tPA, the researchers estimated. And that, they suggested, could allow more than 8,000 people to survive their stroke disability-free.

According to Burke, a treatment rate of 10 percent to 15 percent is a "credible goal."

"I think that until we reach 10 percent nationwide, we've still got a lot of work to do," he said.