The study, authored by Lewis Morgenstern, M.D, professor of neurology, emergency medicine and neurosurgery at the U-M Medical School and a member of the U-M Cardiovascular Centre and led by U-M stroke neurologist Jennifer Majersik, M.D., examined 2,347 patients with ischemic (clot-based) strokes who reported to hospitals, the average age being 71 years. Over half were women.
In the study, the researchers reviewed medical records in detail, looking for information on what time each patient was last known to be without symptoms, and what time they reached the hospital. In some cases, when an exact time for the start of the symptoms was not known, the researchers used an estimate.
They broke the patients up into groups by the time to presentation (arrival) at the hospital: less than three hours, three to six hours, six to 12 hours, and more than 12 hours.
The researchers also assessed how severe the patients- strokes were, and looked for differences in the time to hospital presentation for each severity group.
The patients with the most severe strokes made it to the hospital in the fastest time, with nearly half of them making it in less than three hours.
In contrast, only 28 percent of patients with the mildest level of stroke made it in that time.
The summarised analysis found that only 44 percent of patients who experienced full-blown clot-based strokes got to the hospital even within six hours of the start of their symptoms and 36 percent didn't get there until more than 12 hours had passed.
The damage caused by stroke can be reduced by giving tPA treatment, the only approved treatment for stroke caused by blood clots in the brain, to the patient.
If given intravenously within the first three hours of the start of a stroke, or injected directly into the brain within six hours, tPA can break up clots and stop or slow the damage caused by strokes.
The analysis showed that delay kept many patients away from receiving tPA.
"Efforts to speed up patients' arrival at the hospital are absolutely crucial. We have very effective treatments; we just need to get patients to the hospital as fast as possible," Morgenstern said.
Morgenstern said that a person experiencing a stroke really needed to get to a hospital within two hours of the start of a stroke to have the best chance of receiving tPA.
Another study conducted by the same researchers described the positive effects of an education effort aimed at middle-schoolers.
In this study, kids were tested on three things: their knowledge of what a stroke was, their ability to identify stroke symptoms and their knowledge of what to do if someone around them appeared to be having a stroke.
One group was tested in both sixth and eighth grades but did not receive any specific in-school training about stroke.
The other group was tested in sixth grade before receiving four hours of stroke education each year for three years as part of their school curriculum.
They were tested again at the end of the three years. Parents of both groups were also approached for testing.
The students who had had the in-school training tested better in eighth grade than those who had not, with the most dramatic increase in correct answers seen in the part of the test that assessed whether students knew that calling emergency was the best option for responding to a stroke.
The studies are published in the journal Stroke.