"First pass" mesenteric flow is not necessary - portal vein arterializaton

Portal vein thrombosis (PVT) is such a profound problem that it has been considered to be an absolute contraindication for a liver transplantation (LTx) and I know centers still denying LTx for patients with PVT. In the most cases the donor portal vein is anastomosed with the superior mesenteric vein (SMA) of the recipient using a vascular graft (usually from the same donor). There are some reports about porto-renal anastomoses. The portal vein arterialization (PVA) is the option which recently attracted my interest and I took a look at what was written about this.

In 1995 the group in Essen, Germany reported three cases of PVA in situations of PVT with involvement of the SMV in orthotopic LTx but also in auxillary LTx, in which cases interfering with the native portal flow is not preferable. Three years later the same group reported series of six patients with PVA undergoing auxillary LTx. Two more orthotopic LTx and one auxillary LTx patients were published from Barcelona, Spain in 2001 and three more cases were then reported 2003 from Berlin, Germany. A recent long term observation of a single patient was reported by a group from Paris, France (unfortunately in French only, hence abstract only is available for the majority of the world population).

All those papers report favorable results of the PVA!
The hepatic hemodynamic measurements performed in the Spanish study showed no frightening numbers. To me the more interesting question was whether any metabolic effects would occur after PVA (e.g. encephalopathy) but this was not observed in the reported cases. Liver fibrosis and heart decompensation were apparently reported in veterinary publications which I don't pay any attention to and therefore don't write here about. Liver biopsies showed some sinusoidal dilatation but no major changes.

The main message I read from these publications is that mesenteric flow does not seem to require "first pass" through the liver.
Whether the PVA is completely separated from the splanchnic system (to prevent the known complications of portal hypertension) or is used for augmentation of the portal flow, it appears to be a feasible option which should be taken into consideration when recurrent portal vein thrombosis occurs and threatens the life of a patient.