RESUMO
Nitrates are widely used in the treatment of patients with ischemic heart disease and in those with angina following acute myocardial infarction. Short-term studies indicate that the administration of nitrates may prevent left ventricular (LV) dilation and infarct expansion. Animal models suggest that prolonged nitroglycerin use after infarction may limit LV remodeling similar to that observed with angiotensin-converting enzyme inhibitors. However, to date there have been no trials evaluating the effects of nitrates on LV volumes in patients surviving acute myocardial infarction. We therefore performed a randomized double-blind, placebo-controlled trial designed to investigate the long-term (6 month) efficacy of intermittent transdermal nitroglycerin patches on LV remodeling in 291 survivors of acute myocardial infarction. Patients were randomized to receive either placebo or a nitroglycerin patch that delivered 0.4, 0.8, or 1.6 mg/hour. Gated radionuclide angiography was used to assess serial changes in LV ejection and cardiac volumes. The baseline characteristics of the study population were similar in all 4 treatment groups. The study protocol and the main design-related issues are described.
Assuntos
Hipertrofia Ventricular Esquerda/prevenção & controle , Infarto do Miocárdio/complicações , Nitroglicerina/uso terapêutico , Vasodilatadores/uso terapêutico , Administração Cutânea , Adulto , Idoso , Método Duplo-Cego , Teste de Esforço , Feminino , Imagem do Acúmulo Cardíaco de Comporta , Ventrículos do Coração/diagnóstico por imagem , Ventrículos do Coração/efeitos dos fármacos , Humanos , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Hipertrofia Ventricular Esquerda/etiologia , Hipertrofia Ventricular Esquerda/fisiopatologia , Masculino , Pessoa de Meia-Idade , Nitroglicerina/administração & dosagem , Estudos Prospectivos , Volume Sistólico/efeitos dos fármacos , Resultado do Tratamento , Vasodilatadores/administração & dosagemRESUMO
The efficacy and safety of extended-release isosorbide mononitrate tablets were evaluated in patients with stable effort angina. In a double-blind study, 313 patients with stable effort-induced angina were randomized to receive placebo or extended-release isosorbide mononitrate: 30, 60, 120 or 240 mg once daily in the morning. Serial exercise testing was performed using the standard Bruce treadmill protocol on days 1, 7, 14, 28 and 42 immediately before morning drug administration, and 4 and 12 hours after administration. After initial dosing, all groups that received extended-release isosorbide mononitrate had significant (p < 0.01) increases in mean total exercise time of approximately 30 to 50 seconds in relation to placebo 4 and 12 hours after administration. On day 42, mean changes from baseline in total exercise time of patients who received 120 or 240 mg of extended-release isosorbide mononitrate exceeded placebo by approximately 50 to 60 seconds 4 hours after dosing (p < 0.01), and by 30 to 35 seconds 12 hours after dosing (p < or = 0.05). No significant difference was detected between responses to extended-release isosorbide mononitrate and placebo 24 hours after administration (i.e., immediately before the next dose). Thus, there was neither significant activity nor demonstrable rebound of effort-induced angina (zero-hour effect) at the end of the dosing interval. Transient headache was the most prevalent adverse experience. Extended-release isosorbide mononitrate (120 and 240 mg administered orally once daily) significantly prolonged exercise time to development of moderate effort-induced angina 4 and 12 hours after dosing during long-term therapy, without development of nitrate tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)