Recipient Portal Vein Research Articles

Venous jump grafts for liver transplantation in patients with portal vein thrombosis.

When the recipient portal vein (PV) has thrombosed at or above the confluence of the splenic vein (SV) and superior mesenteric (SMV) vein in a liver transplant recipient, grafts of iliac vein or vena cava can be used in the hilum to bridge the gap to the homograft PV (1, 2). A thrombosis that extends down into the SV and SMV can not be dealt with by this hilar approach, and in most centers the more extensive thrombotic occlusion is a contraindication to candidacy. For a number of years, we have used jump vein grafts in such cases and have evolved a technique that, in its final form, is a simple and highly satisfactory resolution to the problem. Since the need for this kind of vein graft is sometimes not evident until the actual transplantation, the donor team should always bring back long segments of donor iliac vein (1, 3). These vein grafts are kept in a standard tissue culture medium in the refrigerator, and can be used for at least a week. The value of this precaution was dramatically demonstrated by Sheil et al. (4) who used a mesoportal vein graft when they encountered an unexpected portal vein thrombosis in the first patient treated with liver transplantation in Australia. When a decision for a jump graft is made, a segment of the SMV to the right of the superior mesenteric artery is skeletonized below the transverse mesocolon at the root of the small bowel mesentery (Fig. 1). The dissection should be as distal as is necessary to find a soft and compressible vessel. Depending on the anatomic circumstances, a partially or completely occluding clamp is placed on the SMV segment, and the angled distal end of the iliac vein graft is anastomosed to the presenting surface of the SMV. The proximal end of the graft is led superiorly through a hole in the transverse mesocolon either to the right or left of the middle colic vessels, the exact location being guided by transillumination. The graft is brought anterior to the pancreas behind the gastric pylorus and into the subhepatic area (Fig. 1). The rest of the transplantation is carried out in the normal way. The vein graft is anastomosed to the portal vein of the liver graft (Fig. 1). FIGURE 1 Position of completed venous jump Graft. The patients who need these procedure are generally high-risk, and usually have intractable ascites. In spite of this, the procedure itself is technically easy and can be carried out with little blood loss. Ultrasound studies postoperatively allow determination of jump graft patency. Thrombosis of a jump graft has not been seen.

Progress in experimental porcine small-bowel transplantation.

Studies in large animals are needed to overcome technical complications, allograft rejection, and graft-vs-host disease, which are major problems that prevent clinical application of small-bowel transplantation. The small bowel was allografted heterotopically or orthotopically into 30 pigs with the use of cyclosporine, prednisone, and azathioprine. When cyclosporine was given orally to heterotopically transplantation recipients, rejection was frequent, and graft-vs-host disease caused one death. After 30 days of intravenous cyclosporine followed by oral administration, no rejection occurred. Graft-vs-host disease was mild or absent, and there were some long-term survivors. Technical failures were relatively infrequent, but death from sepsis, eg, intra-abdominal abscess, occurred in 17% (5/30). Anastomoses of donor superior mesenteric vein to recipient portal vein offered no advantages over systemic venous drainage. Although the high cyclosporine levels used would be intolerable in humans, these results indicate that successful small-bowel transplantation can be achieved with adequate immunosuppression in a large animal.