For years, hospital emergency physicians have used nitrogylcerin as a gold standard for identifying heart disease as a cause of chest pain. If a patient presents with chest pain, and a nitroglycerin pill or spray under the tongue relieves the pain within a few minutes, the likely diagnosis is coronary artery disease (CAD).
Now a Johns Hopkins study is challenging that belief. Of 459 patients who came to the emergency department at Hopkins' Bayview Medical Center between February and June of this year complaining of chest pain, nitroglycerin relieved chest pain in about 39 percent of patients, whether or not they turned out to have heart disease. Overall, nitroglycerin was only 28 percent accurate in predicting CAD as the source of pain. These findings will be presented Nov. 12 at the American Heart Association's annual Scientific Sessions in Anaheim, Calif.
"This study has the potential to change how emergency departments triage patients with chest pain," says Nisha Chandra-Stobos, M.D., senior author of the study and director of the coronary intensive care unit at Bayview. "Our data suggest that despite the commonly held belief, pain relief with nitroglycerin does not predict coronary artery disease and should not be used to guide diagnosis."
Nitroglycerin works by relaxing the veins (reducing the amount of blood that returns to the heart and easing the heart's workload) and arteries (increasing the heart's blood supply). It's the drug most often used for the one in five patients who comes to the ED complaining of chest pain.
The patients studied had an average age of 58. Forty-six percent were male; 44 percent were smokers; 25 percent were diabetic and 38 percent had a known history of CAD. After initial treatment with nitroglycerin, 261 (57 percent) underwent further cardiac testing. In those with confirmed significant CAD, 39 percent had chest pain relief from nitroglycerin, compared with 38 percent of patients who showed no evidence of coronary artery disease. Among those diagnosed with CAD, just 34.6 percent with a known history of CAD or newly diagnosed with CAD had chest pain relief from nitroglycerin. The frequency of diabetes, traditional CAD risk factors and medication use was similar in patients with or without chest pain relief from nitroglycerin.
Charles A. Henrikson, M.D., first author of the study and a cardiology fellow at Hopkins, says, "Nitroglycerin is still fine to use for patients with chest pain, but physicians must follow them through additional testing to determine whether they truly have CAD."
Other study authors were Eric E. Howell, David E. Bush, Glenn Meininger, J. Shawn Miles and Andrew Bushnell.
Abstract #101662: "Debunking a Myth: Failure of Nitroglycerin-Relieved Chest Pain to Predict Coronary Artery Disease."
Links: Johns Hopkins Bayview Medical Center - Division of Cardiology http://www.jhbmc.jhu.edu/cardiology/cardiology.html
American Heart Association Scientific Sessions http://www.scientificsessions.org/
Media contact: Karen Blum(410)955-1534
Email: kblum@jhmi.edu
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