A hepatofugal flow can be changed to a hepatopetal splenic venous flow via the splenorenal shunt and the hepatopetal portal-mesenteric venous flow is retained after this procedure. This hemodynamic change results in a marked reduction in table 1 the hepatofugal portosystemic shunt flow and a mild increase in the portal venous pressure (5, 6, 16). The distance between the junction of the inferior mesenteric vein and the first branch of the collateral veins on the splenic vein is important when considering SPDPS. A sufficient distance is required for coil embolization. This procedure is anatomically indicated in patients with splenorenal shunts who present with enough distance although the location of the inflow vein must be taken into account.
If the inflow vein (usually the posterior, short, and/or coronary vein) is at least a few centimeters distal from the superior and inferior mesenteric veins, SPDPS can be performed because the splenic vein can be obliterated without impeding the mesenteric venous blood flow. We think that for SPDPS a distance of 4 or 5 cm is necessary for the selective embolization of the splenic vein with metallic coils. Kashida et al. (1) reported three patients in whom embolization of the proximal part of the splenic vein resulted in a disconnection of the mesenteric-portal blood flow from the systemic circulation while preserving the shunt. In these patients SPDPS achieved the immediate and permanent clearing of encephalopathy and in the course of 10�C30-month follow-up there was no evidence of ascites or esophageal varices.
The pre- and postprocedure difference in the portal pressure was 18 mmHg in a patient with a closed shunt and 3 mmHg in another with a preserved shunt. In both of our patients there was enough distance to allow disconnecting the mesenteric-portal blood flow from the systemic circulation while preserving the shunt, therefore we decided to perform SPDPS. Hepatic function is another important factor for evaluating the eligibility of patients to undergo SPDPS. If the procedure is performed in patients with very small liver vascular beds, the slightly increase in the portal pressure and portal blood volume overload can lead to the retention of ascites and worsening of gastroesophageal varices. Even if the portal flow is increased in patients with poor hepatic function, hepatic encephalopathy may not improve because ammonia is not metabolized.
Therefore, this procedure is appropriate only in patients with slightly compromised hepatic function. Mezawa et al. (16) reported a patient with impaired liver function and Child-Pugh class C disease in whom Brefeldin_A SPDPS was successful and elicited no postoperative liver damage. It is currently unknown whether SPDPS is safe and effective in patients with severe liver dysfunction. Shunt occlusion with metallic coils (15) and by selective embolization of the splenic vein has been attempted (16).