Does Chest Pain Relief with Nitroglycerin Mean Coronary Artery Disease?

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The summary below is from the full report titled "Chest Pain Relief by Nitroglycerin Does Not Predict Active Coronary Artery Disease." It is in the 16 December 2003 issue of Annals of Internal Medicine (volume 139, pages 979-986). The authors are C.A. Henrikson, E.E. Howell, D.E. Bush, J.S. Miles, G.R. Meininger, T. Friedlander, A.C. Bushnell, and N. Chandra-Strobos.

What is the problem and what is known about it so far?

Chest pain is a common symptom that can be caused by several conditions. Cardiac causes of chest pain, such as angina and heart attack, are serious and usually require prompt medical attention and treatment. Other causes of chest pain, such as spasm of the esophagus or inflammation of the chest wall, may be less serious and require different treatment than does chest pain related to heart conditions. Therefore, an accurate diagnosis is important to guide proper treatment of patients with chest pain.

Nitroglycerin, a drug that dilates blood vessels, is commonly used to relieve chest pain caused by coronary artery disease. It also relaxes the smooth muscles of vessels and can relieve chest pain from esophageal spasm. Because of its different actions, researchers wonder whether relief of acute chest pain with nitroglycerin reliably indicates that pain was caused by coronary disease.

Why did the researchers do this particular study?

To see whether pain relief by nitroglycerin correctly identifies patients with acute chest pain who have coronary artery disease.

Who was studied?

459 adults with acute chest pain who were admitted to an urban community teaching hospital through the emergency department.

How was the study done?

A health care provider gave nitroglycerin (spray or tablet under the tongue) to patients visiting the emergency department for evaluation of chest pain. Using a standard form, patients rated the severity of their chest pain immediately before and about 5 minutes after receiving nitroglycerin. The researchers labeled pain as relieved if there was a 50% or greater reduction in the intensity of chest pain. All patients were admitted to the hospital for further observation or tests to evaluate the presence of active coronary artery disease. The researchers called patients about 4 months after hospitalization and reviewed medical records to see whether any had died or had repeated hospitalizations, heart attacks, or heart procedures.

What did the researchers find?

Nitroglycerin relieved pain in 39% of all patients. It relieved pain in 35% of the patients who had subsequent evidence of active coronary disease. It relieved pain in 41% of the patients who had no subsequent evidence of active coronary disease. At 4 months, there were no major differences in outcomes between patients who did and did not have pain relieved by nitroglycerin.

What were the limitations of the study?

The doctors who were caring for the patients were aware of the reported responses to nitroglycerin. This may have influenced their decision to further test for coronary artery disease. Also, all patients didn't get the same tests to diagnose or exclude active coronary disease.

What are the implications of the study?

In emergency department settings, relief of chest pain with nitroglycerin does not help diagnose active coronary artery disease.