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Cardiac MRI A Better Predictor of Heart Attack, Death for Women with Symptoms of Cardiovascular Disease, AGH Researchers Find

Thursday, October 21, 2010

The use of non-invasive cardiac magnetic resonance imaging (MRI) appears to be more effective than conventional diagnostic procedures, such as nuclear stress testing and coronary angiography, in the diagnosis of women with symptoms of ischemic heart disease, according to research by specialists from Allegheny General Hospital (AGH) published in the Journal of the American College of Cardiology: Cardiovascular Imaging.

These findings, which will be featured in the October issue of JACC: Cardiovascular Imaging, were released early online today.

“Traditionally, blockage of the coronary artery is widely-associated with disease in men-- there is a clear connection with heart attack,” said Mark Doyle, PhD, a cardiac MRI physicist at AGH and an investigator in the Women’s Ischemia Syndrome Evaluation (WISE) trial. “In women, the association is not as strong and screening and diagnosing heart disease in women has proven to be highly problematic using conventional diagnostic procedures.”

“In our study, MRI identified evidence of heart disease in women for whom conventional testing indicated otherwise. Given the prevalence of this disease and the specific challenges we have faced with regards to its manifestations in women, these results are extremely encouraging,” said Robert W.W. Biederman, MD, director of AGH’s Cardiac MRI Center and a leading cardiac MRI specialist.

According to the American Heart Association, cardiovascular disease is the leading cause of death for women, killing an estimated 500,000 annually and exceeding the next four causes of death combined. Women are 15% more likely than men to die of a heart attack, twice as likely to suffer a second heart attack in the six years following the first, and 50% more likely to die within one year compared to a similarly aged man with a heart attack.

The WISE study was part of a comprehensive, National Heart, Lung and Blood Institute-sponsored project that was established to improve coronary artery disease detection and treatment in women. The AGH study was conducted jointly with the University of Alabama at Birmingham.

In this phase of the WISE study, 100 women with ischemic heart disease and without obstructive coronary artery disease (as assessed by coronary angiography) underwent MRI-Myocardial Perfusion Imaging within a week of enrolling in the trial.

Cardiac MRI uses powerful magnets to provide computer generated three-dimensional images of the heart and arteries, providing high-resolution pictures of the heart’s chambers and vessels non-invasively and without the need for radioactive contrast agents. The technology has been shown to be extremely effective at imaging the heart muscle, identifying damage from heart attacks, diagnosing congenital heart abnormalities and evaluating diseases of the aorta, such as dissections and aneurysms and is currently the clinical standard for these diseases.

Rather than looking for significant localized blockages, the study takes a more global look at the heart and scans for low-level perfusion and small vessel disease.

The researchers found when using a cardiac MRI approach, that women with abnormal perfusion and symptoms of ischemia but no significant obstructive coronary artery disease experienced more adverse events than their non-symptomatic counterparts.

The women were monitored for approximately three years, undergoing interviews at six weeks after the MRI and then yearly thereafter. At follow-up, 23 patients (23%) in the study either died or had a heart attack or other serious heart condition.

In the past, with the absence of apparent anatomical disease as defined by angiography, women have been less aggressively treated, with symptoms often being dismissed, according to Dr. Biederman.

“We’re attempting to see, what catheterizations, nuclear stress tests, and echocardiography are missing,” Dr. Biederman said. “With MRI, if there is cardiovascular disease, we’re able to define it and now we believe we have a new tool to detect it. Making the correct diagnosis is the single best thing we can do to improve and reduce treatment costs and it’s a great comfort to both the physician and the patient to have a definitive diagnosis.”

Though the identification of regional vascular defects within the heart remains an important and necessary diagnostic tool, the WISE trials shows that, for women in particular, MRI can detect more subtle, global conditions not detectable by classical tests that can put them at higher risk for a serious cardiac event.

The AGH investigators plan to use data from this and subsequent studies to develop a more specific diagnostic protocol that will help physicians analyze MRI test results and better assess patient risk.

“There is no smoke without fire,” Doyle said. “We hope to use the MRI data to develop a detailed sequence of the progression of heart disease and learn how to fit the symptoms into the progression so that we can alert people to their risk for disease.”

AGH has played a key role in the development of cardiac MRI, joining a select group of leading research centers that includes Johns Hopkins University, Stanford University Medical Center, Beth Israel Hospital, Duke University and the University of Alabama. AGH’s state-of-the-art Cardiac MRI Center opened in 2000 and is one of just four cardiac MRI programs in the country accredited by the Intersocietal Commission for the Accreditation of Magnetic Resonance Laboratories.