Beta-blockade and brachial artery hemodynamics in hypertension.
The effect of systemic adrenergic blockade on hypertensive brachial arteries was studied in humans with pulsed Doppler flowmetry. Blockade of beta-receptors by the nonselective beta-blocking agent propranolol did not modify the brachial artery diameter, whereas pindolol increased this parameter for the same degree of blood pressure reduction. The beta1-selective blocking agents atenolol and bisoprolol caused similar decreases in blood pressure and a reduction in the diameters of the brachial artery and abdominal aorta, respectively. The combination of alpha- and beta-blockade produced a rapid drop in blood pressure but did not change the brachial arterial diameter. Thus, following beta-blockade, the arterial diameter increased, did not change, or even decreased despite an adequate blood pressure reduction. It is suggested that beta-blockade in some instances resets the pressure-diameter curve and therefore has a direct action on the arterial wall independent of the mechanical effect of blood pressure reduction.
Safar
M E
ME
Department of Internal Medicine and INSERM (U337), Broussais Hospital, Paris, France.
Laurent
S A
SA
London
G M
GM
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D001262:Atenolol / Q000494:pharmacology / Q000627:therapeutic use; D017298:Bisoprolol / Q000494:pharmacology / Q000627:therapeutic use; D001916:Brachial Artery / Q000187:drug effects* / Q000502:physiology; D005542:Forearm / Q000098:blood supply; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D018342:Receptors, Adrenergic, beta-1 / Q000502:physiology*
D000319:Adrenergic beta-Antagonists; D018342:Receptors, Adrenergic, beta-1; D001262:Atenolol; D017298:Bisoprolol