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Achieving sustained improvement in myocardial perfusion: role of isosorbide mononitrate
1Division of Nuclear Medicine and Cardiology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California 90048-1865, USA.
Insights
Antianginal agents, particularly nitrates, improve chronic stable angina by enhancing myocardial perfusion. Noninvasive imaging techniques like SPECT and PET offer sensitive assessments of these drug effects on ischemic heart regions.
Area of Science:
- Cardiology
- Nuclear Medicine
Background:
- Chronic stable angina treatment traditionally relies on exercise treadmill tests (ETT), which are insensitive to myocardial ischemia.
- Nitrates may improve angina by redirecting blood flow to ischemic myocardium, but invasive studies are limited.
- Noninvasive imaging, including SPECT and PET, can assess myocardial perfusion defects.
Purpose of the Study:
- To review studies on nitrate effects on coronary blood flow and perfusion defects in chronic stable angina.
- To discuss preliminary data on long-term nitrate treatment's impact on myocardial perfusion.
Main Methods:
- Review of angiographic studies on nitrates.
- Assessment of quantitative SPECT and PET in evaluating myocardial perfusion defects.
- Discussion of preliminary data from a long-term nitrate treatment study.
Main Results:
- Nitrates may preferentially direct blood flow to ischemic areas.
- Noninvasive imaging techniques show potential for assessing drug-induced perfusion changes.
- Preliminary data suggests long-term nitrate treatment impacts myocardial perfusion.
Conclusions:
- Noninvasive imaging offers a sensitive method to evaluate antianginal drug efficacy.
- Nitrates demonstrate potential in improving myocardial perfusion in chronic stable angina.
- Further research is needed on long-term nitrate effects using advanced imaging.
Abstract:
The efficacy of antianginal agents in the treatment of patients with chronic stable angina has traditionally been evaluated by performance measures, such as the exercise treadmill test (ETT). Although reliable and reproducible, ETT is not a sensitive measure of changes in myocardial ischemia. The effects of antianginal agents on coronary blood flow and myocardial perfusion have been less frequently studied. Angiographic studies have demonstrated that nitrates may operate by preferentially directing blood flow to ischemic regions of the myocardium. These investigations have been limited, however, by the invasive nature of the evaluation. Measurements of regional myocardial perfusion may also be made with noninvasive tests. Both quantitative single-photon emission computed tomography (SPECT) and positron emission tomography (PET) have been employed, but few studies have used these techniques to assess the effects of antianginal drugs (in general) and nitrates (in particular) on changes in reversible myocardial perfusion defects. Studies that have evaluated the direct effects of nitrate treatment on coronary blood flow and myocardial perfusion defects in patients with chronic stable angina are reviewed, and preliminary data from a study of the effects of long-term nitrate treatment on myocardial perfusion are discussed.