Background/aims: Endothelin-1 (ET-1) is a potent vasoconstrictor that may be involved in the pathogenesis of splanchnic and renal hemodynamic changes associated with portal hypertension. The aim of this study was to measure the concentration of ET-1 and of its precursor Big endothelin-1 (Big ET-1) in the systemic circulation as well as in the splanchnic and renal venous beds and to evaluate changes after the relief of portal hypertension following transjugular intrahepatic portosystemic shunt placement.
Methods: Plasma concentrations of ET-1 and of Big ET-1 were measured in the vena cava, renal vein, hepatic vein and portal vein in ten patients with cirrhosis and refractory ascites before and 1-2 months after transjugular intrahepatic portosystemic shunt. The porto-caval gradient, creatinine clearance, plasma aldosterone and renin activity, as well as daily urinary sodium excretion were measured at the same time.
Results: The plasma concentration of ET-1 and Big ET-1, respectively, in peripheral blood of normal volunteers were 0.28 +/- 03 and 3.95 +/- 0.34 pg/ml; the concentrations of both peptides were higher in patients with cirrhosis, both in vena cava (0.61 +/- 0.14 and 10.01 +/- 1.47 pg/ml), hepatic vein (0.62 +/- 0.13 and 13.93 +/- 1.77 pg/ml), portal vein (1.21 +/- 0.12 and 17.84 +/- 1.98 pg/ml) and renal vein (0.76 +/- 0.12 and 14.21 +/- 1.55 pg/ml). Moreover ET-1 and Big ET-1 concentrations were more elevated in the portal vein than in the vena cava (+98% and +70%) and slightly higher in the renal vein as compared to the vena cava (+25% and +42%). After transjugular intrahepatic portosystemic shunt, a rise in creatinine clearance and urinary sodium excretion (+49%; and +53%) was observed together with a marked reduction in plasma aldosterone and renin activity (-59% and -49%). ET-1 and Big ET-1 concentrations remained unchanged in the vena cava whereas a significant reduction of ET-1 and Big ET-1 occurred both in the portal vein (-43% and -44%) and in the renal vein (-53% and -29%). Portal vein and renal vein concentrations of both peptides became similar to vena cava levels.
Conclusions: Splanchnic and renal hemodynamic changes occurring in patients with cirrhosis and refractory ascites could be related to the production of ET-1 by splanchnic and renal vascular beds. This was abolished by transjugular intrahepatic portosystemic shunt, which could explain the exacerbation of systemic vasodilation and the improvement in renal perfusion observed after the procedure.