Pharmacists can aid in stroke treatment

March 5, 2007

Can pharmacist involvement boost the level of inpatient stroke care?

Can pharmacist involvement boost the level of inpatient stroke care?

Absolutely, said Hong Kao, pharmacist at Canada's Trillium Health Centre in Mississauga, Ontario. Before a clinical pharmacist joined the stroke care team at the 700-bed regional stroke center in 2004, about half of stroke patients were receiving secondary prevention therapy, Kao told the International Stroke Conference (ISC) meeting in San Francisco last month. With a pharmacist on the team, 95% of patients were getting an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin-receptor blocker (ARB), and 83% were getting a statin at discharge.

Positive results were also reported for a randomized controlled trial showing the superiority of low molecular weight heparin over unfractionated heparin for the prevention of deep vein thrombosis (DVT) and pulmonary embolism (PE) following ischemic stroke. "This is a long-awaited comparison," said David Sherman, M.D., director of neurology at the University of Texas Health Science Center, San Antonio. "Low molecular weight heparin will assume the role of the preferred anticoagulant for stroke patients."

The relative risk reduction found in the Prevention of VTE after Acute Ischemic Stroke with LMWH Enoxaparin (PREVAIL) trial was associated with a comparable safety profile, Sherman said. PREVAIL data are currently undergoing pharmacoeconomic analysis, he added.

The picture is less clear in treating children with arterial ischemic stroke. Because there are no secondary stroke prevention trials in children, there are no treatment guidelines, said Heather Fullerton, M.D., assistant professor of neurology and pediatrics at the University of California, San Francisco. The International Pediatric Stroke Study (IPSS) found significant variations in antithrombotic treatment around the world. More than 25% of pediatric stroke victims have a recurrence, Fullerton said, but more than 36% of IPSS patients were given no antithrombotic treatment whatsoever. About 29% received anticoagulation, and around 30% got aspirin.

In U.S. centers, 23% of patients got anticoagulation therapy versus 44% at non-U.S. centers. "This reflects a lot of uncertainty about how children should be treated," Fullerton said.

IPSS data on the use of tPA reinforced those uncertainties. While tPA has revolutionized stroke treatment in adults, there are no data for children, said Catherine Amlie-Lefond, M.D., assistant professor of neurology at the Medical College of Wisconsin, Milwaukee. IPSS found many children being treated with tPA later than would be acceptable in adults. In adults, intravenous use of tPA is indicated within three hours of the onset of symptoms. IPSS found that 57% of pediatric patients were given IV tPA more than three hours after onset. Results were better with intra-arterial tPA, indicated for use within six hours of onset in adults. Only 33% of pediatric patients failed the adult guidelines.

Overall, treatment outcomes for children are not favorable, Amlie-Lefond noted. Only 17.6% of children had no discernible effects at discharge following tPA treatment. IPSS found neurological deficits in 64.7% of patients, 11.7% mortality, and 5.8% amputation due to arterial thrombosis following tPA. "We desperately need age-appropriate dosing guidelines for tPA," she said.

Christopher Gray, M.D., was chief investigator on the United Kingdom Glucose Insulin in Stroke Trial (GIST-UK). The six-year, multicenter randomized controlled trial concluded that intensive management of hyperglycemia after stroke has no clinical impact. "There is good evidence that reducing glucose levels following myocardial infarct or acute surgical illness reduces mortality," Gray said. "We did not know if there would be a similar effect in stroke." There is not. Reducing glucose levels after stroke lowers blood pressure by about nine points, Gray said, but there was no difference in survival between the placebo and intervention arms in the GIST-UK study.