LAUSR

The article in this current issue of Liver Transplantation by Elnaggar et al. is noteworthy for 2 main reasons. First, it draws attention to the benefits of the mesoportal bypass as a means of ameliorating the symptoms of portal hypertension in patients with portal vein thrombosis. Second, it includes adult patients in an area that has been almost exclusively the domain of pediatric surgery and hepatology. The report describes 64 patients over a 13-year period who had undergone 1 of 4 types of operations to manage complications of portal hypertension. These include what the authors term “portal preserving” operations and “portal diverting” operations. The term portal preserving is applied to both the mesoportal operation as well as the distal splenorenal shunt (DSRS; implying that the 2 operations are similar in their effects on the portal circulation). The mesoportal operation, or the meso-Rex bypass, was described as a means to restore portal blood flow to the liver after portal vein thrombosis after liver transplant. The technique was later applied to children with idiopathic portal vein thrombosis. It is therefore a restorative operation in which the mesenteric venous blood is redirected into a liver that has suffered from a relative deprivation of portal blood flow. The DSRS mitigates complications of portal hypertension by shunting blood from gastroesophageal varices and the enlarged spleen typical in patients with portal vein thrombosis into the left renal vein, but it does not increase or restore portal blood flow to the liver. This article also elaborates on how many children or adults make up this cohort of patients. Although there were 64 patients in the study, Table 2 includes the data from only 39 patients for the cross-sectional volume analysis comparing the patients with the standard liver volume for adults and children. Therefore, the impact of the authors’ findings is diminished by the fact that only 56% of patients had both presurgical and at least 1 postsurgical cross-sectional imaging study available for comparison. More disappointing is that in the patient population of greatest interest, those having had the mesoportal bypass, only 11 patients (7 children and 4 adults) had preoperative and postoperative crosssectional imaging allowing for volume comparison. In the 4 adults, there was no significant change in either liver or spleen volume, but in the total of 11 patients, liver volume did increase significantly. There was no change reported in the volume of the spleen. Undoubtedly, the statistical significance of the results was affected by the relatively small number of patients in this subgroup. The authors do not examine the group of distal splenorenal shunts separately from the mesoportal group. It would have been interesting to see if there was a difference between these 2 groups that make up the portal preserving category. Although one can understand why the mesoportal patients would experience an increase in the size of the liver after the restoration of mesenteric blood flow, it is not clear at all why patients in the DSRS group should change in a similar fashion. It is highly likely that the small number of patients in that group would not permit statistical analysis. In Table 4, only 14 patients of the total of 40 in the portal preserving group are included for the statistical demonstration that the liver increases in size after these 2 operations. It is possible that the failure to demonstrate a decrease in spleen size after the portal preserving operations is simply a function of the small number of patients included in the analysis. Others have demonstrated that the mesoportal operation in children does indeed surpass the DSRS in the relief of hypersplenism. The authors’ observation, despite the lack of statistical significance, that the results in children may be better than those seen in adults is consistent Abbreviation: DSRS, distal splenorenal shunt.