BACKGROUND: Studies of the in vivo vascular reactivity of the peripheral circulation to pressor agents in cirrhosis have produced conflicting results, possibly because of changes in mean arterial pressure that make it difficult to clearly separate peripheral and central effects. The aim of the present study was to assess the reactivity of the forearm circulation to pressor agents in vivo without activating central control systems. METHODS: Forearm blood flow was measured by venous occlusion strain gauge plethysmography in the basal state and during the infusion of subpressor doses of norepinephrine and angiotensin II into the brachial artery in 10 male patients with well-compensated alcoholic cirrhosis and 10 male age-matched controls. Plasma renin activity and aldosterone and angiotensin II concentrations were assayed. Forearm and systemic sympathetic nervous system activity was estimated using a norepinephrine spillover technique. RESULTS: Basal forearm blood flow, renin angiotensin aldosterone system activity, and forearm sympathetic nervous system activity were similar in both the control and cirrhotic groups. The cirrhotic patients showed an impaired response to both norepinephrine and angiotensin II. CONCLUSIONS: There is impaired reactivity of the peripheral vasculature to pressor agents in cirrhosis, indicating that the control of vascular tone is disturbed even in well-compensated cirrhosis.
BACKGROUND: Studies of the in vivo vascular reactivity of the peripheral circulation to pressor agents in cirrhosis have produced conflicting results, possibly because of changes in mean arterial pressure that make it difficult to clearly separate peripheral and central effects. The aim of the present study was to assess the reactivity of the forearm circulation to pressor agents in vivo without activating central control systems. METHODS: Forearm blood flow was measured by venous occlusion strain gauge plethysmography in the basal state and during the infusion of subpressor doses of norepinephrine and angiotensin II into the brachial artery in 10 male patients with well-compensated alcoholic cirrhosis and 10 male age-matched controls. Plasma renin activity and aldosterone and angiotensin II concentrations were assayed. Forearm and systemic sympathetic nervous system activity was estimated using a norepinephrine spillover technique. RESULTS: Basal forearm blood flow, renin angiotensin aldosterone system activity, and forearm sympathetic nervous system activity were similar in both the control and cirrhotic groups. The cirrhotic patients showed an impaired response to both norepinephrine and angiotensin II. CONCLUSIONS: There is impaired reactivity of the peripheral vasculature to pressor agents in cirrhosis, indicating that the control of vascular tone is disturbed even in well-compensated cirrhosis.
Authors: Young-Mi Go; Chan Woo Kim; Douglas I Walker; Dong Won Kang; Sandeep Kumar; Michael Orr; Karan Uppal; Arshed A Quyyumi; Hanjoong Jo; Dean P Jones Journal: Am J Physiol Regul Integr Comp Physiol Date: 2014-11-05 Impact factor: 3.619