Effect of nitroglycerin on peripheral large arteries in hypertension.

1 Blood pressure, systemic arterial compliance, and diameter, blood flow velocity, volumic flow and impedance of the brachial artery were measured before and after intravenous administration of nitroglycerin (15 micrograms/min during 15 min) in 11 patients with sustained essential hypertension. 2 For the evaluation of the diameter of the brachial artery, a bidimensional pulsed Doppler was used, enabling the angle of the ultrasound beam relative to the flowing stream of blood to be measured with an error of less than 2%. 3 After nitroglycerin, systolic pressure significantly decreased (P less than 0.01) without significant change in diastolic and mean arterial pressures, cardiac index, stroke index and total peripheral resistance. 4 Systemic arterial compliance and brachial artery diameter significantly increased (P less than 0.001; P less than 0.01) while velocity and blood flow of the brachial artery were unchanged. 5 The pattern of the input impedance of the brachial artery was consistent with a predominant effect of nitroglycerin on the viscoelastic properties of peripheral large arteries. 6 The study provided evidence that, in hypertensive patients, nitroglycerin has a direct effect on peripheral large arteries, causing an increase in arterial diameter and compliance, thus leading to a predominant decrease in systolic pressure.