A patient undergoing a stress test.
Many people who experience chest pain are needlessly undergoing stress tests or imaging of their arteries, a University of British Columbia cardiologist has found, leading him and his U.S. collaborators to create an easy-to-use online risk assessment tool.
The new online tool, available at www.promiserisktools.com, could be used to spare thousands of patients in North America from the complications of testing, including radiation exposure, allergic reactions or anxiety.
“In addition, it could reduce the strain on the health system, freeing up resources for other procedures,” said Christopher Fordyce, a Clinical Assistant Professor in the UBC Division of Cardiology.
Current guidelines say that a person who has experienced chest pain should undergo one of two tests: a stress test, in which the patient walks on a treadmill or rides a stationary bike while heart rhythm, blood pressure and breathing are measured, or computed tomography (CT) imaging of their coronary arteries, the main vessels nourishing the heart, to look for blockages or narrowing.
But a re-examination of data from a large North American study of over 10,000 people experiencing chest pain found that 27 per cent of people who underwent those tests had normal results and no other heart-related problems for two years afterwards.
Based on that information, Dr. Fordyce, the Associate Director of the Cardiac Intensive Care Unit at Vancouver General Hospital, worked with colleagues at Tufts Medical Center in Boston and Duke University School of Medicine in North Carolina to analyze the characteristics of the people in the study, to see if certain criteria could be weighted to predict which ones would have a normal result. He and his collaborators described their research in an article published last week in JAMA Cardiology.
The 10 criteria include information easily and typically obtained during exams: age, gender, racial or ethnic status, a history of hypertension, diabetes, high cholesterol, a family history of coronary artery disease, whether the person smoked, exhibited symptoms unrelated to physical exertion or stress; and their “good” cholesterol levels.
Using those criteria, Dr. Fordyce and his collaborators divided the patient pool into 10 groups, from highest risk to lowest risk, and calculated what weighting of criteria could predict who would be in the lowest-risk decile.
They incorporated that weighting into the online tool that doctors can use to guide their recommendations to patients who are experiencing chest pain. It is the first tool that aims to reduce testing of people with chest pain.
“Around 10 per cent of those patients would be categorized as having minimal risk, with a very low likelihood of having an adverse clinical event or severely abnormal test,” Dr. Fordyce said. “For those patients, the doctor can explain that little benefit would be gained from doing further tests, and recommend deferring further testing to see how the patient fares over the subsequent weeks and months.”
In the U.S., 4 million stress tests are done each year, so this tool could theoretically reduce that by 400,000 – and that doesn’t include CT imaging of the coronary arteries, the other option recommended under current guidelines.
Doctors can begin using the tool immediately, but it won’t likely be incorporated into official guidelines until it’s validated through a randomized controlled trial, Dr. Fordyce says. Until then, he and his colleagues suggest that physicians use it in “shared decision-making” with patients.