EFFECT OF ORTHOTOPIC TRANSPLANTATION OF LIVER ON SYSTEMIC AND SPLANCHNIC HEMODYNAMICS IN CONSCIOUS RAT

The long-term cardiovascular effects of orthotopic liver transplantati on (OLT) were studied in conscious Lewis rats with a radioactive micro sphere technique. Three months after OLT with an all-suture technique for graft revascularization (s-OLT), all hemodynamic parameters were s imilar to control. OLT with ''cuffs'' fitted to the portal vein and in frahepatic inferior vena cava (c-OLT) led to prominent hemodynamic dis turbances including 1) hyperkinetic circulation with increased cardiac index (CI; 22%; P < 0.05) and decreased mean arterial pressure (15%; P < 0.05) and total peripheral resistance (TPR; 28%; P < 0.05); 2) a s light increase in portal pressure (11.8 +/- 0.9 vs. 9.3 +/- 1.7 mmHg i n control) and marked portal-systemic shunting (51 +/- 11 vs. 0.05 +/- 0.04% in control; P < 0.05); 3) increased hepatic arterial blood flow (0.49 +/- 0.06 vs. 0.27 +/- 0.04 ml . min(-1). g liver wt(-1); P < 0. 05); 4) splanchnic vasodilation with vascular resistance significantly (P < 0.05) lower in the liver, stomach, and large intestine; and 5) i ncreased blood flow and decreased vascular resistance in the kidneys a nd heart. Ganglionic blockade with chlorisondamine (5 mg/kg body wt iv ) indicated that the increase in CI seen in the c-OLT rats was probabl y sympathetically mediated, whereas the increase in renal blood flow w as a reflection of the increase in CI. After ganglionic blocker admini stration, TPR and regional vascular resistances decreased to approxima tely the same extent in the control and c-OLT groups, indicating that vascular sympathetic tone was unchanged in the c-OLT rats. Our data su ggest that OLT per se (s-OLT) has no long-term effect on hemodynamics in the rat but that c-OLT causes hemodynamic changes similar to those found in portally hypertensive rats.