The present study explores the acute and chronic effects of isosorbide-5-mononitrate (5-ISMN) 80 mg administration on dipyridamole-induced myocardial ischemia. Continuous administration of organic nitrates leads to a decrease in their therapeutic efficacy (nitrate tolerance). Exercise stress test used to recognize development of nitrate tolerance, presents many limitations. It is not known whether dipyridamole stress echocardiography is a useful test to assess the efficacy and nitrate tolerance. In 22 patients with stable myocardial ischemia we prospectively studied the acute and chronic effects of 5-ISMN 80 mg daily on dipyridamole-induced myocardial ischemia, the ability of dipyridamole stress echocardiography to evaluate development of nitrate tolerance. After acute treatment with 5-ISMN dipyridamole stress echocardiography was negative in 19 out of 22 patients (p <0.001 vs placebo). During the sustained phase, dipyridamole stress echocardiography returned positive after placebo in all 19 patients and after active drug in 18 (NS vs placebo). Our results indicate that acute administration of 5-ISMN antagonizes dipyridamole-induced myocardial ischemia and show the loss of antischemic efficacy in 95% of patients during sustained treatment, demonstrating that dipyridamole stress echocardiography is a useful tool to assess the presence of nitrate tolerance.
|Number of pages||4|
|Publication status||Published - 1999|
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Cardiology and Cardiovascular Medicine