Intrarenal blood flow, circulation time, and cortical vascular volume in patients with cirrhosis

The pathogenesis of renal functional impairment in patients with cirrhosis is still poorly understood, although it is probably linked to intrarenal haemodynamic alterations, such as renal cortical vasoconstriction and opening of intrarenal shunts. To elucidate the intrarenal haemodynamic pattern in patients with cirrhosis, in eight patients with this disease mean renal blood flow (MRBF) and cortical blood flow (CBF) were determined by means of the xenon-133 washout technique; in the same subjects mean intrarenal circulation time for plasma (t) and fastest circulation time for plasma(t0) were determined by means of injection of human serum albumin tagged with technetium-99m into the renal artery. Moreover, cortical vascular volume (CVV) was obtained in all subjects by means of the following formula: CVV = CBF x t. Fourteen normal subjects constituted a control group for MRBF, 9 subjects for CBF, and 4 subjects for t, t0, and CVV. In patients with cirrhosis MRBF and CBF were significantly less than in controls; t did not show any significant alterations, whereas t0 was significantly shorter than in controls. CVV was also significantly impaired. It is concluded that renal cortical vasoconstriction is a characteristic of the renal haemodynamic pattern in patients with cirrhosis. It is suggested that the decrease in t0 is due to the opening of intrarenal shunts and that is likely to be the consequence of renal vasoconstriction.