Modeling splanchnic hemodynamics after distal splenorenal shunt: a computer simulation and sensitivity analysis.
The distal splenorenal shunt operation was specifically designed to preserve portal flow and maintain elevated portal pressure. However, although this goal is met in the immediate postoperative period, flow decreases over time, and in as many as 75% of alcoholic patients, portal flow is lost in the first year. Various explanations have been offered for this observation, and modifications of the original operation have been proposed (splenopancreatic disconnection). Although other portacaval shunts have been successfully modeled as electrical circuits, this approach has never been described for the distal splenorenal shunt. In this study we developed a computer program that modeled the distal splenorenal shunt as an electrical circuit. We performed an analysis to determine the sensitivity of portal flow to changes in each resistance element and then performed a series of simulation experiments to critically examine the various explanations offered for the gradual changes in hepatic hemodynamics. We found that portal flow was most sensitive to resistance in the renal vein followed by resistance in the anastomosis. The simulation experiments suggested a new alternative to splenopancreatic disconnection--restricting the ability of the splenic vein, anastomosis, or renal vein to dilate. Additional clinical studies will be needed to test these predictions.
Rypins
E B
EB
Department of Surgery, University of California, Irvine Medical Center, Orange 92668.
Goldstein
L
L
Sarfeh
I J
IJ
D003097:Collateral Circulation; D003198:Computer Simulation; D006439:Hemodynamics; D006801:Humans; D008102:Liver Circulation; D008955:Models, Cardiovascular; D012680:Sensitivity and Specificity; D013152:Splanchnic Circulation; D013164:Splenorenal Shunt, Surgical; D014655:Vascular Resistance