Small Intestine Transplantation

KEY FACTS

Terminology

Isolated small bowel transplant (SB Tx) is primarily for "short gut syndrome"
Multivisceral Tx (liver, ± pancreas, ± part of stomach)
- Usually for liver failure due to chronic total parenteral nutrition (TPN)
Donor bowel has copious lymphoid tissue and bacteria
- Higher prevalence of rejection and infectious complications than solid visceral Txs

Imaging

Vascular complications: Thrombosis, stricture, pseudoaneurysm (arteries or veins)
- Less common than for other Tx procedures
Mesenteritis: Present to some degree in all SB Tx recipients
Opportunistic infections: May affect any organ, including allograft
Pneumatosis: Usually not due to ischemia
Ascites: Usually loculated, nonspecific finding
- Chylous ascites: Presence of fat-fluid levels
Post-Tx lymphoproliferative disorder (PTLD)
- More common in SB (up to 30%) and multivisceral Tx than most other solid organ Tx recipients
- More common within SB allografts than in host organs
Rejection and graft-vs.-host disease
- Both common, cannot be distinguished on imaging
Dilation of SB lumen
- May result from dysmotility, adhesion, ischemia, or rejection
Imaging protocols: Multiplanar CT, ± CT angiography, displays most important anatomical and pathophysiological information pertinent to SB Tx
Upper GI series to evaluate motility and status of proximal bowel anastomosis

Clinical Issues

SB Tx: 1-year patient survival (90%); graft survival (~ 75%)
- Multivisceral Tx: 1-year patient survival (80%)
- 5-year patient survival: 60%
Worse than for solid organ Tx recipients

Graphic demonstrates some of the altered anatomy in a small bowel transplantation (SB Tx) procedure. The SB allograft is usually anastomosed proximally to the distal duodenum or proximal jejunum of the recipient, and distally to the sigmoid

, with a temporary "chimney" ileostomy in the right lower quadrant. This ostomy allows convenient access to the allograft in the perioperative period for endoscopic visualization and biopsy procedures and may be permanent. The donor superior mesenteric vein (SMV) is anastomosed to the host SMV or portal vein