RESUMO
A randomized within-patient double-blind acute and sustained study was performed to compare transdermal nitroglycerin (NTG) patches (5 and 10 mg) and matching placebo in 10 patients with chronic stable angina pectoris confirmed on exercise thallium scintigraphy or coronary angiography, or both. Patients performed treadmill tests 2 and 24 hours after application of patches on the first and last days of each of the 3 treatment periods. Effects caused by sequence of treatments and training with serial testing were prominent so the changes in the well-known parameters did not favor either of the active doses over placebo. Quantification of training effects and its subtraction from performance index disclosed that 10 mg of transdermal NTG caused significant increase in performance in both the acute and sustained stages of therapy in comparison to pretreatment performance. This was not observed with 5 mg and placebo treatments. To our knowledge, this is the first trial to study the efficacy of transdermal NTG with a more objective parameter that permitted elimination of training effects of serial exercise testing.