Reconstitution of blood supply of the denuded bronchial stump.

Background: Our aim was to study the process of microcirculatory reconstitution in the bronchial stump after pneumonectomy.
Methods: Eighteen juvenile pigs (median weight 40.6 kg) were randomly assigned to three groups. In all animals left pneumonectomy was performed and the stapled bronchial stump (median length 3.8 cm) carefully denuded. Group I animals received coverage of the stump by intercostal flap. In group II, the stump was covered with TachoComb, an impermeable hemostatic fleece; and group III served as a control without any coverage of the stump. Animals were sacrificed at day 14 after surgery. Vascular density was evaluated in serial histologic sections at multiple levels stained with CD-31 antibody. One-way analysis of variance and the Wilcoxon test were used for data analysis.
Results: At autopsy, stumps of group III animals were totally covered by adjacent mediastinal structures. In group I, intercostal flaps were viable and completely healed to the bronchial stumps. There were no signs of infection or stump insufficiency in these groups. In all group II animals, empyema developed, and stumps were found necrotic at macroscopic and histologic evaluation. Statistical analysis revealed significantly lower vascular density of mature vessels in the area of the bronchial stump in group II compared with both other groups.
Conclusions: Reconstitution of microcirculation of the denuded bronchial stump after pneumonectomy takes place in a centripetal way from adjacent viable tissue. Hence, the purpose of covering the bronchial stump is the improvement of blood supply rather than mechanical reinforcement.