Meso-Rex Bypass—A Procedure to Cure Prehepatic Portal Hypertension: The Insight and the Inside (original) (raw)

2014, Journal of the American College of Surgeons

Prehepatic portal hypertension (PHPH), related to thrombosis and the cavernomatous transformation of the portal vein (PVC), is the single most common cause of portal hypertension in children. Although it can be secondary to the direct damage that relates to neonatal catheterization of the umbilical vein, the latter condition represents <25% of cases, 1-7 and no cause is found in most cases (idiopathic PHPH). Even less commonly, it relates to regional trauma (or surgery, eg, after liver transplantation), tumors, or infection (eg, peritonitis, abscess). Although in the adult age group there is a clear correlation between pre-existing thrombophilia and PVC, coagulation abnormalities are not found to be primarily related to PVC in children, in fact, only minor disorder types have been reported in a small proportion of patients, and most coagulation profile abnormalities observed are acquired and secondary. Anatomically speaking, the initial thrombotic process seems to mainly involve the portal vein trunk, to which it is eventually limited in the typical disease condition; a variable extension, either downstream into the intrahepatic radicals, or upstream into the splanchnic system, or both, can be observed. Remarkably, in children who have had catheterization of the umbilical vein, the processes more than likely start in an inverse manner, with the thrombus initiating within the liver as a consequence of the direct (chemical, physical, or infection) damage of the intrahepatic veins and, more precisely, the left portal system. 2,7,12 A diffuse splanchnic venous thrombosis is exceptional in children (although it is relatively common in adults with thrombophilia). Although part of the portal system is not reachable for decompressive surgery (as the portal trunk and sometimes other veins are thrombosed), various types of portosystemic shunt have been performed with success; the type of shunt depends on the venous anatomy of each patient and the team's preferences (mesocaval and various splenorenal types of shunt). 14-20