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Changes in systolic and diastolic blood pressure, heart rate, arterial blood flow and vascular resistance in the arm and in the leg were investigated in 9 healthy volunteers (22-40 years) after oral dosing with bisoprolol 10 mg, propranolol 40 mg, and placebo in a randomized double-blind cross-over study. Arterial blood flow and vascular resistance were determined in brachial and femoral arteries with unimpeded circulation, after exclusion of the hand or foot by placing a tourniquet on the wrist or ankle, and during post-ischaemic hyperaemia. Distal arterial occlusion allows one to isolate a predominantly muscular circulation in the forearm or, to a lesser extent, in the leg. Both active drugs induced a significant fall in heart rate and systolic blood pressure versus placebo with no significant difference between the drugs. Brachial and femoral flow rates were reduced by both drugs probably due to a fall in cardiac output, but the two beta blockers produced different effects on vascular resistance: propranolol significantly increased brachial vascular resistance compared with placebo and bisoprolol, both during unimpeded circulation and during occlusion of the hand by a wrist tourniquet. Bisoprolol had no influence on brachial vascular resistance. Both drugs induced small increases in femoral vascular resistance. The different action on local vascular resistance in the brachial artery territory could be interpreted as the expression of the high beta 1 selectivity of bisoprolol leaving the vascular beta 2 receptors unopposed, whereas non-selective propranolol acts on both beta-adrenoceptor subtypes.

Vascular reactivity to heat and cold was studied in 11 normal subjects without vascular disease and in 23 patients with Raynaud's phenomenon (etiologies: Raynaud's disease, scleroderma, thoracic outlet syndrome). The study of hand and digital temperatures and brachial artery blood flow was performed in ambiant conditions (room temperature 23.5 +/- 1 degree C) and after thermal (cold or warm exposure: 10, 33 and 40 degrees C), mechanical and metabolic modifications (with a wrist tourniquet). In these conditions, blood flow was studied at each temperature, before, during and after 3 minutes ischemia of the hand. Analysis of results showed that vasomotricity possibilities were preserved but that responses were not identical. Patients with primary Raynaud's phenomenon, and even more those with scleroderma as well, had reduced brachial artery blood flow after cooling (10 degrees C). After ischemia, maximal blood flow was also reduced. The microcirculatory disease existing in Raynaud's phenomenon limits the vasodilator capacity of hand vessels, but probably more in tissues with vascular lesions. Vasodilation seems to be limited during exposure to low well as high temperatures, but vasoconstriction capacity is not disturbed.