Portaprival collaterals following distal splenorenal shunt. Incidence, magnitude and associated portal perfusion changes.

Collateral venous pathways develop between the high pressure portal vein and low pressure splenic vein following distal splenorenal shunt. This review of angiography in 50 patients with cirrhosis prior to and 1 year after DSRS shows that 98% developed collaterals: 72% transpancreatic, 48% transgastric, and 46% colonic. Multiple pathways developed in 64% of patients. Grading of the size of these collaterals showed that in 74% these exceeded the size of the portal and/or superior mesenteric vein. The effect of these collaterals on portal perfusion showed that 32% lost perfusion at 1 year, but significantly (P less than 0.05) more alcoholics (48%) lost perfusion than nonalcoholics (16%). The size, site and number of collaterals was not different between etiologies. Late follow-up in a subset of 32 of the patients showed no change in the site, and minimal increase in size of the collaterals at 3-11 years, with no further loss of portal perfusion. We conclude that virtually all patients develop collaterals after DSRS, these are along predictable pathways and are of significant size in the majority. However, development of collaterals per se does not equate to loss of portal venous flow, and a stable pattern is set in the first year after shunt. Characterization of these pathways will permit new approaches to minimizing their development.