must be traced into the hilum and divided close to the liver in order to access the hepatic artery and portal vein. The hepatic artery and portal vein must be divided close to the liver beyond their bifurcation in order to preserve length. Patients with biliary atresia will often have unusual anatomical features such as preduodenal portal vein, retroperitoneal continuation of the inferior vena cava, left sided vena cava and situs inversus abdominis. Anatomical anomalies are common and are not always diagnosed with pretransplant imaging.

Long standing portal hypertension may contribute to progressive shunting of mesenteric blood away from the liver leading to hypoplasia of the portal vein. In extreme cases the portal vein size is less than 2 mm in diameter and flow is minimal and makes the portal vein unsuitable for use as a conduit of mesenteric blood to the new liver. One must trace the portal vein to the confluence of the splenic and superior mesenteric veins where the flow of blood is acceptable. Vein grafts from the donor may be used to bridge the distance between the native vein and the donor liver.4 In pediatric transplantation, the native inferior vena cava is often left in place.5 The vena cava is mobilized completely, but the adrenal vein is preserved. Retrohepatic branches may be ligated and divided individually. Alternately, clamps can be placed above and below the liver on the IVC and the liver dissected sharply off the vein. Vein branches can then be oversewn under direct vision.

Implantation of the New Organ

Over 50% of infant transplants are done with organs that have been reduced in size from older donors.6,7 These include size reduced cadaveric organs, split livers where the right lobe is preserved for transplantation into another recipient, and living donor procured segments.

Cadaveric organs that are reduced in size for a single recipient only, are reduced in size on the back table. When the donor's weight is less than four times that of the recipient, the entire left lobe can usually be transplanted. All structures to the right lobe are divided and ligated. The parenchyma is then divided in the plane of the inferior vena cava and gall bladder. Particular attention must be paid to the area of the confluence of the hepatic veins to insure that all major veins are secured. If the donor is more than four times the weight of the recipient, the size of the liver will only permit implantation of segments 2 and 3. Parenchymal division takes place to the right of the falciform ligament.

For organs that are considered for transplantation into two recipients, the division of the liver can be done either in or ex vivo depending on the logistics of the transplant, cold ischemic time, and preference of the teams.8,9 Important technical features in splitting a liver are preservation of segment 4 arterial supply, division of the bile duct preferably beyond the confluence of the segments 2 and 3 ducts, and preservation of as much of the length of the left portal vein. Hepatic venous anomalies are uncommon. The left hepatic vein is usually sufficient to provide adequate venous drainage of segments 2 and 3 or even the entire left lobe.

When the operative field is ready for implantation, the graft is positioned in such a manner as to facilitate proper portal vein orientation. If the liver is piggybacked onto the cava, the venous orifices of all 3 hepatic veins may be used as a

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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