Incidence, Clinical Significance, and Outcome of Vascular Alterations in Intestinal Biopsies After Isolated Small Bowel Transplantation: A Single-Center Experience

Background: Mild and moderate vascular alterations in intestinal biopsies after isolated small bowel transplantation (SBT) have uncertain clinical significance. Methods: We retrospectively investigated the incidence, association with acute cellular rejection (ACR), treatment, and outcome of mild and moderate vascular changes in 15 adult SBTs performed between December 2000 and October 2003. The semiquantitative Ruiz score for vascular changes in intestinal mucosa was used. Results: A total of 332 biopsies were analyzed. All patients had at least one sample showing mild or moderate vascular injury, which was globally found in 117 biopsies (35% of the total; 29% mild and 6% moderate). No cases of severe vascular injury were observed. First appearance of vascular alterations occurred 2 to 36 days after SBT (median: 6). Patients with vascular injury had a higher incidence of associated ACR than patients without this feature (16% vs 5%, P = .001). Patients with moderate vascular injury were also more likely to have moderate-to-severe ACR than patients showing no or mild vascular changes (14% vs 2%; P = .015). Treatment of rejection was more frequently administered with simultaneous diagnosis of ACR than in cases of isolated vascular alterations (84% vs 26%; P <.0001). Only one graft (7%) was lost due to severe ACR. Discussion: Mild and moderate vascular changes are common findings in early post-SBT biopsies. They are frequently associated with ACR and parallel its severity. The clinical impact of mild or moderate vascular injury appears to be of little relevance.