New Analysis Suggests That Giving tPA to Patients with Mild Strokes Could Prevent 2,000 Cases of Disability Annually
ARTICLE IN BRIEF
In an analysis of outcomes for stroke patients in a population-based study, researchers estimated that administering tissue plasminogen activator to patients who have mild strokes could prevent more than 2,000 cases of disability and save more than $200 million in health care costs annually.
LOS ANGELES — Giving thrombolytic drugs to eligible patients with mild ischemic strokes could prevent more than 2,000 cases of disability and save more than $200 million in health care costs annually, researchers reported here.
Patients with mild strokes are typically denied tissue plasminogen activator (tPA) because the pivotal studies that established its efficacy excluded mild cases, said Pooja Khatri, MD, lead researcher of the study and associate professor of neurology and director of acute stroke at the University of Cincinnati Academic Health Center in Ohio.
It's been assumed that patients with mild strokes “generally [do] well and the risk of tPA treatment, which includes a slight but significant risk of life–threatening bleeding in the brain, would not be worth the benefit,” she said here at the American Stroke Association International Stroke Conference in February.
In fact, one in three patients who suffer a mild stroke experiences some disability three months later, Dr. Khatri said.
To determine the impact of treating mild strokes, Dr. Khatri and colleagues analyzed hospital records from all 437 patients diagnosed with mild ischemic stroke at 16 sites in the Greater Cincinnati/Northern Kentucky (GCNK) region in 2005. The patients arrived at the hospital within 3.5 hours of onset — well within the 4.5-hour window for treatment with tPA.
Of the total, 251 were considered to have mild strokes, with a score of 5 or less on the 42-point National Institutes of Health Stroke Scale (NIHSS). Only four (1.0 percent) were given tPA. However, 150 (62 percent) of the remaining patients would have been candidates for the drug if the mildness of their stroke was disregarded as a reason to deny them tPA treatment.
Extrapolating these population–representative figures to the entire nation, 43,180 people with mild strokes would be eligible for tPA each year, Dr. Khatri said.
After excluding those with baseline disability (estimated at 37 percent, based on GCNK data) and assuming an effect size of 13 percent as suggested by the pivotal NINDS trial for patients with more severe strokes, use of tPA could prevent 3,761 additional cases of disability among mild stroke patients each year, she said.
“Research suggests, however, that tPA would be less effective in patients with mild stroke. If we assume an 8 percent effect size — the minimum clinically meaningful effect — there would be 2,176 fewer cases of disability annually,” Dr. Khatri said.
“If the disability prevented is assumed to be moderate, with a conservatively estimated lifetime cost of $100,000 — as proposed by J. Samsa et al, in a 1999 paper in the Journal of Clinical Epidemiology — then over $200 million in expenditures on stroke disability would be saved annually,” she concluded.
The researchers identified a few limitations of the study: it relied on retrospective chart review and assumed that the rate of baseline disability in the GCNK area applied to the US population.
Steven M. Greenberg, MD, PhD, vice chair of the ISC meeting committee and professor of neurology at Harvard Medical School, said the results are “most likely generalizable.”
The findings underscore the “huge impact” of mild strokes on patients' lives and the US health care system, he said.
“It would be hard to find patients who consider a mild stroke unimportant. You can almost argue there is no such thing as a mild stroke, that every stroke is significant,” Dr. Greenberg, who was not involved with the study, said.
tPA isn't without risks, chiefly brain bleeding. But studies suggest people with mild stroke are less likely to have a hemorrhage than those with the more severe strokes in which it is routinely used, Dr. Greenberg said.
Still, further study of tPA in mild stroke is needed, Dr. Khatri said. NIH funding is being sought for a large-scale two-part study of IV tPA called Potential of rtPA for Ischemic Strokes with Mild Symptoms, or PRISMS. Participants will include patients with mild strokes, as reflected by an NIHSS score of 5 or less and symptoms that are not clearly disabling.