Systemic and renal hemodynamic changes during acute unilateral renal arterial stenosis

The acute effects of unilateral renal arterial stenosis on systemic and renal hemodynamics were studied in chronically instrumented, conscious dogs. Graded stenosis of one renal artery for 90 min produced graded increases in arterial blood pressure and plasma renin activity and falls in contralateral renal blood flow and total peripheral conductance. There were no significant changes in cardiac output. The changes were transient after mild or moderate renal arterial stenosis but were sustained after severe stenosis. Pentolinium treatment did not significantly affect the hypertension or contralateral renal vasoconstriction caused by moderate or severe renal arterial stenosis. This indicates that the autonomic nervous system did not play a major role in the response to stenosis. In contrast, teprotide abolished the increases in arterial pressure, the contralateral renal vasoconstriction, and the fall in total peripheral conductance in response to stenosis. Thus the acute hypertension following unilateral renal arterial stenosis was due to a decrease in total peripheral conductance caused by decreased conductance of the stenotic kidney due to the stenosis itself (about 20%); vasoconstriction of the contralateral kidney (about 20%), and vasoconstriction of other systemic vasculature (about 60%). The results suggest that angiotensin II was responsible for the vasoconstriction of both the contralateral kidney and the other systemic vasculature.