The effect of selective visceral caval shunt on plasma lipids and cholesterol dynamics

This investigation was done to measure the effects of selective visceral caval shunting on plasma lipids and cholesterol dynamics. Study groups consisted of 9 dogs with a mesocaval shunt, 10 with a splenic pancreatoduodenal shunt, 5 animals in each of the above groups with completed portacaval shunt, and 5 controls. Cholesterol specific activity curves were plotted after intravenous ¹⁴C cholesterol and from these radioisotope disappearance curves the half lives of the rapidly and slowly miscible cholesterol pools were measured, and the rapidly and slowly miscible cholesterol pool sizes and the cholesterol production rates were calculated. Sequential plasma cholesterol levels (x ± 1 SD) for the mesocaval shunt group were 146 mg% ± 20 at baseline, 150 mg% ± 20 after selective shunt, and 80 mg% ± 20 after completion of the portacaval shunt. Comparable values for the splenic pancreatoduodenal shunt group were 150 mg% ± 13, 148 mg% ± 12, and 90 mg% ± 20. The mesocaval group mean plasma triglyceride levels (mg%) ± 1 SD were 49 ± 11 at baseline, 33 ± 8 after this selective shunt, and 31 ± 7 after completion of the portacaval shunt. For the splenic pancreatoduodenal group, these values were 52 ± 12, 41 ± 13, and 35 ± 12 (mg% ± 1 SD). Thus plasma cholesterol did not change after either selective shunt; however, after portacaval shunt was completed a significant decrease (p < 0.01) of 40 to 45% occurred. In contrast, there was a significant (p < 0.05) reduction in the plasma triglyceride after either selective shunt (22 to 33%). This triglyceride reduction was maintained, in both groups, after completion of the portacaval shunt. None of the cholesterol dynamics parameters showed any statistical difference among operative groups or between each operatve group and the control group. The authors believe that the single most important finding in this study is the demonstration in the dog that the concurrent diversion of blood from the jejunum, ileum, and proximal colon, as well as from the beds of the duodenum, pancreas, stomach, and spleen, is necessary for the induction of a plasma cholesterol lowering by portal venous systemic diversion.