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Effect of intracoronary glyceryl trinitrate on perfusion distribution in the collateralised human myocardium
Insights
Intracoronary glyceryl trinitrate reduced blood flow through collateral vessels in the heart. This medication increased perfusion in the native coronary arteries without affecting blood pressure or heart rate.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Interventional Cardiology
Background:
- Coronary artery disease often involves collateral circulation, which can supply blood to ischemic areas.
- Understanding how vasoactive agents affect collateral flow is crucial for managing myocardial ischemia.
Purpose of the Study:
- To investigate the effect of intracoronary glyceryl trinitrate on myocardial perfusion distribution in patients with coronary collaterals.
- To assess the impact of a specific, low-dose glyceryl trinitrate on collateral-mediated versus native coronary artery perfusion.
Main Methods:
- Studied eight patients with angiographically confirmed left-to-right coronary collaterals.
- Utilized double isotope imaging with technetium-99m and iodine-131 labeled albumin macroaggregates.
- Employed a within-patient control design, validated by 12 control subjects.
Main Results:
- Intracoronary glyceryl trinitrate (60 micrograms) significantly reduced fractional perfusion mediated by collaterals.
- The same dose of glyceryl trinitrate led to a significant increase in perfusion within the native coronary artery bed.
- These effects occurred without significant alterations in systemic blood pressure or heart rate.
Conclusions:
- Intracoronary glyceryl trinitrate selectively alters myocardial perfusion distribution in the presence of coronary collaterals.
- The drug diminishes collateral flow while enhancing native coronary artery perfusion, suggesting a potential therapeutic role in specific ischemic conditions.
Abstract:
The effect on myocardial perfusion distribution of intracoronary glyceryl trinitrate in a dose (60 micrograms) insufficient to cause alterations in systemic blood pressure or heart rate was studied in eight patients with angiographically demonstrated collaterals from the left coronary system to the distal right coronary artery. Double isotope imaging using technetium-99m and iodine-131 labelled albumin macroaggregates allowed each patient to serve as his own control. The reproducibility of the imaging and data handling techniques was shown in 12 control patients. Glyceryl trinitrate caused a significant diminution in the collateral-mediated fractional perfusion while increasing that of the native coronary bed.