Atrial Fibrillation Stroke 'Tragedy'
Too Many Strokes in Heart-Rhythm Patients Due to Coumadin Undertreatment
Aug. 28, 2008 -- Far too many people with atrial fibrillation, an abnormal heart rhythm, suffer preventable strokes, a University of Toronto study suggests.
The "tragedy" is that Coumadin, an inexpensive blood thinner, could prevent about half of these strokes, yet few high-risk patients get proper treatment, says neurologist David J. Gladstone, MD, PhD.
"On one hand, we have an extremely effective and cheap medication for stroke prevention -- Coumadin -- yet on the other hand it remains under-used in people who would benefit most from it," Gladstone says in a news release.
Gladstone's team at the University of Toronto's Sunnybrook Health Sciences Center looked at 597 patients with atrial fibrillation who suffered a first stroke. Stroke in atrial fibrillation patients is particularly severe, so it's no surprise that 20% of the patients died and 60% suffered disabling strokes.
These patients, because of their age, diabetes, or other factors, were at particularly high risk of stroke. All of them should have been taking Coumadin with blood levels of the drug above 2.0 on a blood-thinness scale called the INR.
But only 10% of these stroke patients had an INR this high. Only 40% of these high-risk patients were getting Coumadin, and nearly 30% weren't getting any blood thinner at all.
The finding galls John Worthington, MBBS, of the University of New South Wales in Sydney, Australia.
"As a stroke specialist at two hospitals and a university, it is frustrating to see people disabled or even dying from avoidable stroke," Worthington tells WebMD. "If we were [giving Coumadin to] all the people that should be on this anticoagulant, we would reduce the amount of fatal and disabling stroke by at least 20% and often more. We have a gap between 20 years of compelling evidence about what we should do and what we actually do in treating the high stroke risk in atrial fibrillation."
This happens in the U.S., too, says Leonardo Tamariz, MD, MPH, assistant professor of medicine at the University of Miami Miller School of Medicine. In a soon-to-be-published study, Tamariz and colleagues found that only half of atrial fibrillation patients were taking Coumadin.
That's not too big a surprise, because not all patients are at high risk of stroke. But Tamariz found that high-risk patients were much less likely to be treated with Coumadin than low-risk patients.
"That is not concordant with the American College of Cardiology recommendations," Tamariz tells WebMD. "The ACC recommends that for low-risk patients you could actually use aspirin, because their lifetime stroke risk is about twice the normal risk. But high-risk patients should be on Coumadin because their stroke risk is 8% to 9%, and Coumadin could reduce it to 4%."
Coumadin: Lifesaver and Nuisance
What's the problem? Why aren't patients who should be on Coumadin getting the drug? And why are so many patients on Coumadin getting too little protection?