Transdermal nitroglycerin patch therapy reduces the extent of exercise-induced myocardial ischemia: Results of a double-blind, placebo-controlled trial using quantitative thallium-201 tomography

Objectives. This study prospectively evaluated whether transdermal nitroglycerin patches could limit the extent of exercise-induced left ventricular ischemia as assessed by quantitative thallium-201 tomography. Background. Although antianginal medications are effective at reducing chest pain symptoms in patients with coronary artery disease, there is limited evidence that these agents can also reduce myocardial ischemia. Methods. This was a randomized, double-blind, parallel, placebo-controlled trial evaluating nitroglycerin patch therapy in patients in stable condition with angiographic coronary artery disease and no previous myocardial infarction. All patients were weaned from antianginal agents and had a baseline symptom-limited treadmill test followed by thallium-201 tomography. Forty patients with perfusion defects involving ≥5% of the left ventricle were randomized to receive either intermittent (12 h on/off) active nitroglycerin patch therapy (0.4 mg/h) or placebo. Exercise tomography was repeated a mean (±SD) of 6.1 ± 1.8 days after randomization. Results. Patients randomized to receive active patch therapy had a significant reduction in their total perfusion defect size (−8.9 ± 11.1%) compared with placebo-treated patients (−1.8 ± 6.1%, p = 0.04), which was most apparent in those with the largest (≥20%) baseline perfusion defects (−11.4 ± 13.4% vs. 1.0 ± 3.6%, respectively, p < 0.02). Furthermore, 7 (33%) of 21 patients receiving active therapy had a ≥10% decrease in their perfusion defects compared with only 1 (5%) of 19 patients randomiztd to receive placebo (p = 0.002). Nitrate therapy did not significantly reduce heart rate, blood pressure or double product, indicating benefit through enhancement of coronary blood flow. Conclusions. Short-term, intermittent nitroglycerin patch therapy significantly reduces myocardial ischemia, particularly in patients with large ischemic perfusion defects. Thallium-201 tomography can be used to assess sequential changes in the extent of exercise-induced left ventricular ischemia.