Decrease of nitric oxide end-products during coronary circulation reflects elevated basal coronary artery tone in...

Area of Science:

• Cardiovascular Research
• Endothelial Function
• Nitric Oxide Biology

Background:

• Vasospastic angina (VSA) is characterized by reversible coronary artery spasm.
• The role of nitric oxide (NO) in VSA pathophysiology remains incompletely understood.
• Basal coronary artery tone is a key factor in VSA development.

Purpose of the Study:

• To investigate the role of nitric oxide (NO) in the coronary circulation of VSA patients.
• To examine the relationship between NO and basal coronary artery tone in VSA.
• To assess endothelial dysfunction in VSA using NO end-products.

Main Methods:

• Evaluated nitric oxide end-products (NOx) in coronary sinus and arterial blood using HPLC-Griess system.
• Compared NOx levels between nine VSA patients and nine controls.
• Measured coronary artery luminal diameter via quantitative coronary arteriography.
• Provoked coronary spasm using intracoronary ergonovine maleate.

Main Results:

• The coronary venous-arterial NOx difference was negative in VSA patients, unlike controls.
• A negative correlation was observed between NOx difference and basal coronary artery tone (r = -0.91, p < 0.01).
• A positive correlation was found between NOx difference and ergonovine dose for spasm (r = 0.77, p < 0.05).

Conclusions:

• Reduced NOx in VSA suggests coronary endothelial dysfunction.
• Endothelial dysfunction contributes to increased basal coronary artery tone in VSA.
• Impaired NO bioavailability may increase susceptibility to ergonovine-induced spasm in VSA.