Nitroglycerin: Should We Still Ask?

Clinicians have long used the response to sublingual nitroglycerin for diagnostic and prognostic purposes in a variety of settings. In stable outpatients with chest pain, pain relief by nitroglycerin has been 1 of 3 components of the most commonly used definition of typical angina (1, 2). In acutely ill patients who present to the hospital, relief of chest pain at rest with nitroglycerin has been assumed to indicate a cardiac cause of the pain. In acutely ill patients with ongoing myocardial ischemia, failure of chest pain to respond to sublingual nitroglycerin is believed to indicate a more severe problem with a higher risk for early adverse events.

The study reported by Henrikson and colleagues (3) in this issue is an important addition to the evidence on the diagnostic value of chest pain relief by nitroglycerin. The authors screened 1098 patients admitted with “chest pain” or to “rule out MI.” They identified 459 patients who developed chest pain under medical supervision and could quantitate the chest pain on a scale of 1 to 10 before and after acute nitroglycerin administration. Patients who had a 50% or greater reduction in the intensity of chest pain within 5 minutes were classified as nitroglycerin responsive. Those who did not were classified as nitroglycerin unresponsive. The authors then used various criteria to determine whether “active” coronary artery disease (CAD) was present, including elevated troponin T levels, significant CAD by coronary angiography, positive results on an exercise test with or without imaging, clinical diagnosis by the attending physician, and the presence of …