PERIPHERAL VASCULAR TONE IN PATIENTS WITH CIRRHOSIS - ROLE OF THE RENIN-ANGIOTENSIN AND SYMPATHETIC NERVOUS SYSTEMS

Objective: The aims of the study were to establish the roles of angiot ensin II and of the cardiopulmonary baroreceptor reflex in the regulat ion of peripheral vascular tone in patients with cirrhosis. Methods: F orearm blood flow responses to subsystemic, locally active intrabrachi al infusions were measured in patients with Child's Grade C cirrhosis and matched controls using bilateral venous occlusion plethysmography. Responses were determined to the angiotensin II type I receptor antag onist, losartan, noradrenaline, angiotensin II and the nitric oxide sy nthase inhibitor, L-N-G-monomethyl arginine. Results: Losartan at 30 a nd 90 mu g/min caused no significant change in blood flow in controls, but caused 23 +/- 6% and 27 +/- 5% increases in patients respectively (p < 0.001). Lower body negative pressure caused a mean bilateral red uction in forearm blood flow of 20 +/- 4% in controls (p < 0.001) but only tended to reduce flow (9 +/- 5%; p = 0.06) in patients (p < 0.001 ; controls vs, patients). Noradrenaline, angiotensin II and L-N-G-mono methyl arginine caused significant vasoconstriction (p < 0.001) in bot h patients and controls although angiotensin II caused significantly l ess vasoconstriction in patients (p = 0.01), Conclusions: We conclude that angiotensin II makes an important contribution to basal periphera l vascular tone in patients with cirrhosis in the face of reduced vasc ular responses to its local administration. In addition, the vasoconst rictor response to cardiopulmonary baroreceptor unloading is attenuate d despite normal vascular responses to noradrenaline. These responses are consistent with chronic activation of the renin-angiotensin and sy mpathetic nervous systems in patients with advanced cirrhosis, (C) 199 8 Elsevier Science B.V.