New method of predicting stroke in heart patients

June 12, 2001

St. Louis, June 13, 2001 -- Researchers at Washington University School of Medicine in St. Louis have developed a formula to predict the risk of stroke in patients with an irregular heart rhythm called atrial fibrillation.

"Our hope is that this new classification scheme will help physicians select the appropriate course of treatment for patients with atrial fibrillation," says Brian F. Gage, M.D., who led the study. Gage is assistant professor of medicine at the School of Medicine and medical director of Barnes-Jewish Hospital's blood thinner clinic. The results are published in the June 13 issue of the Journal of the American Medical Association.

Patients with atrial fibrillation, an irregular, uncoordinated contraction of heart muscles, are estimated to have a fivefold increased risk of stroke. A blood thinner called warfarin sodium (sold as Coumadin® and others) often is used to reduce this risk, but the drug itself can cause hemorrhage and other side effects. It also is more expensive and more difficult to administer and monitor than the alternative treatment, aspirin.

To help predict when the benefits of warfarin outweigh the risks, two earlier studies completed by two other research groups determined independent factors that significantly increase the risk of stroke. However, the studies reached somewhat different conclusions: The Atrial Fibrillation Investigators (AFI) found that stroke risk correlated with prior stroke, advanced age, hypertension and diabetes; the Stroke Prevention and Atrial Fibrillation (SPAF) team found that prior stroke, blood pressure, recent heart failure and the combination of being over 75 years old and female increased the risk of stroke.

"The two predictor models were helpful, but discrepancies between them sometimes led to confusion," says Gage. "We needed a simple, uniform system to help select warfarin for patients at moderate or high risk of stroke, while avoiding this potentially dangerous blood thinner in low-risk patients."

So Gage and colleagues combined the factors from both models and developed a points system called CHADS2, an acronym for the five factors: Congestive heart failure, Hypertension, Age, Diabetes and Stroke. Since both the AFI and SPAF found that a history of stroke is the best predictive factor, it was given a value of two points, delineated by the "2" at the end of the mnemonic. The other factors each are allocated one point. Patients therefore are assigned a score ranging from 0 to 6. In general, the researchers suggest prescribing warfarin to patients with a CHADS2 rating of one or greater, depending on the patient's preferences and risk of hemorrhage.

In collaboration with Peer Review Organizations representing seven states, the team obtained data from 1,733 Medicare beneficiaries aged 65 to 95 years. They followed each patient for an average of 1.2 years and assembled a National Registry of Atrial Fibrillation (NRAF). They then compared the predictive value of each of the three models -- CHADS2, AFI and SPAF.

The AFI and SPAF schemes both predicted stroke better than chance, but CHADS2 yielded significantly more accurate results than either of these models. In addition, the risk of stroke as estimated using CHADS2 ranges from less than two percent to roughly 18 percent. Both AFI and SPAF include only three categories -- low, moderate and high risk -- with stroke risk ranging from roughly one percent to ten percent.

"Having a wider range of scores provides a more quantitative approach to predicting stroke, which is very helpful," explains Gage. "For example, even for high-risk patients, it's important to know how high their score is so that you can take extra precautions if necessary during future surgeries and other medical treatments."
-end-
Gage BF, Waterman AD, Shannon W, Boechler M, Rich MW, Radford MJ. Validation of clinical classification schemes for predicting stroke. Journal of the American Medical Association, 285(22), 2864-2870, June 13, 2001.

Funding from the Agency for Healthcare Research and Quality supported this research.

The full-time and volunteer faculty of Washington University School of Medicine are the physicians and surgeons of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient-care institutions in the nation. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC Healthcare.

Washington University School of Medicine

Related Stroke Articles from Brightsurf:

Stroke alarm clock may streamline and accelerate time-sensitive acute stroke care
An interactive, digital alarm clock may speed emergency stroke care, starting at hospital arrival and through each step of the time-sensitive treatment process.

Stroke patients with COVID-19 have increased inflammation, stroke severity and death
Stroke patients who also have COVID-19 showed increased systemic inflammation, a more serious stroke severity and a much higher rate of death, compared to stroke patients who did not have COVID-19, according a retrospective, observational, cross-sectional study of 60 ischemic stroke patients admitted to UAB Hospital between late March and early May 2020.

'Time is vision' after a stroke
University of Rochester researchers studied stroke patients who experienced vision loss and found that the patients retained some visual abilities immediately after the stroke but these abilities diminished gradually and eventually disappeared permanently after approximately six months.

More stroke awareness, better eating habits may help reduce stroke risk for young adult African-Americans
Young African-Americans are experiencing higher rates of stroke because of health conditions such as high blood pressure, diabetes and obesity, yet their perception of their stroke risk is low.

How to help patients recover after a stroke
The existing approach to brain stimulation for rehabilitation after a stroke does not take into account the diversity of lesions and the individual characteristics of patients' brains.

Kids with headache after stroke might be at risk for another stroke
A new study has found a high incidence of headaches in pediatric stroke survivors and identified a possible association between post-stroke headache and stroke recurrence.

High stroke impact in low- and middle-income countries examined at 11th World Stroke Congress
Less wealthy countries struggle to meet greater need with far fewer resources.

Marijuana use might lead to higher risk of stroke, World Stroke Congress to be told
A five-year study of hospital statistics from the United States shows that the incidence of stroke has risen steadily among marijuana users even though the overall rate of stroke remained constant over the same period.

We need to talk about sexuality after stroke
Stroke survivors and their partners are not adequately supported to deal with changes to their relationships, self-identity, gender roles and intimacy following stroke, according to new research from the University of Sydney.

Standardized stroke protocol can ensure ELVO stroke patients are treated within 60 minutes
A new study shows that developing a standardized stroke protocol of having neurointerventional teams meet suspected emergent large vessel occlusion (ELVO) stroke patients upon their arrival at the hospital achieves a median door-to-recanalization time of less than 60 minutes.

Read More: Stroke News and Stroke Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.