Endogenous endothelin maintains coronary artery tone by endothelin type A receptor stimulation in patients undergoing coronary arteriography

22 subjects undergoing diagnostic coronary arteriography (14 received intervention [7 with normal coronary arteries, 7 with coronary artery disease], 8 received control), mean age 53 years.

BQ-123 (selective ET(A) receptor antagonist; 100 nmol/min) in 0.9% saline, infused into the left coronary artery at a rate of 1 ml/min for 60 minutes.

0.9% saline alone infused into the left coronary artery.

Blood flow velocity in the left anterior descending coronary artery (measured using a Doppler flow guidewire) and diameter of proximal and distal left anterior descending coronary artery segments (measured by coronary arteriography) at the end of the 60-minute infusion.surrogate