Microvessel density at different levels of normal or injured bile duct in dogs and its surgical implications.

BACKGROUND: Ischemic recurrent stricture after surgical repair for iatrogenic bile duct injury (BDI) remains a challenge in clinical practice. The present study was designed to investigate whether ischemia is universal and of varied severity at different levels of the proximal bile duct after BDI. METHODS: A total of 30 beagle dogs were randomly divided into control, BDI, and BDI-repaired groups. The BDI animal model was established based on the classic pattern of laparoscopic cholecystectomy-related BDI. The animals were sacrificed on postoperative day 15, and bile duct tissue was harvested to assess microvessel density (MVD) at selected levels of the normal, post-BDI and BDI-repaired bile duct with the CD34 immunohistochemistry technique. RESULTS: In the control group, MVD at level H (high level) was remarkably higher than that at level L (low level). No significant difference was found between MVDs at levels H and M (middle level), as well as at levels M and L. However, the tendency was noted that the closer the level to the hilus, the greater the MVD at that level. In both the BDI and BDI-repaired groups, MVDs at level H were generally greater than those at level L, despite the unremarkable differences between MVDs at neighboring levels. In these two groups, a similar tendency of MVD distribution to that in the control group was found; the closer the level to the injury site, the lower was the MVD at that level. Moreover, compared with the MDVs at the levels M and L in the control group, MVDs at the corresponding levels in the BDI and BDI-repaired groups were all remarkably reduced (P<0.05). In addition, MVDs at all three levels in the BDI group significantly declined further after BDI repair. CONCLUSIONS: After BDI, universal ischemic damage in the injured proximal bile duct develops close to the injury site, while close to the hilus, ischemia is relatively slight. High hepaticojejunostomy, rather than low biloenterostomy or end-to-end duct anastomosis, should be recommended for BDI repair. Great care should be taken to protect the peribiliary plexus during repair.