Chronic effects of pindolol on the arterioles, large arteries, and veins of the forearm in mild to moderate essential hypertension.

The effects of pindolol were studied on the large arteries, arterioles, and veins of the forearm in 13 patients with essential hypertension after 12 weeks of dosing. The methods used were pulsed Doppler velocimetry of the brachial artery and strain gauge mercury-in-silicone rubber plethysmography of the forearm. Compared with placebo baseline values, chronic pindolol significantly decreased systolic and diastolic blood pressure (P less than 0.001), pulse pressure (P less than 0.001), and pulse rate (P less than 0.05). A significant increase was observed in brachial artery diameter (P less than 0.01), brachial artery blood flow and velocity (P less than 0.001), and forearm arterial flow (P less than 0.001). Forearm vascular resistance and venous tone were decreased (P less than 0.001 and P less than 0.05, respectively), whereas forearm arterial compliance was increased (P less than 0.001). These results demonstrate a dilatory effect on large and small peripheral arteries and on veins of pindolol after chronic dosing, which leads to improvement in the conduction and buffering arterial function of the forearm.