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In order to assess the effect of the omentum on early neovascularization of bronchial anastomoses, we performed left lung autotransplantation in dogs and wrapped the bronchial anastomosis circumferentially with a viable pedicled omental flap raised from the abdomen. Postmorten radiographic injection studies (silicone rubber) were made 1, 3, 4, and 7 days postoperatively. Bronchial artery filling distal to the anastomosis was identified 4 days postoperatively in dogs in which omentum was used. By contrast, a 15 to 30 day period was required for bronchial artery reconstitution without omentum.

The effect of low-dose immunosuppressive therapy upon the healing of the bronchial anastomosis and skin wounds following lung autotransplantation was evaluated. Autotransplantation was performed in two groups of dogs: Group 1(15 dogs) received no immunosuppression and Group 2 (13 dogs) received postoperative immunosuppression with methylprednisolone (2 mg/kg) and azathioprine (1.5 mg/kg). Two to four skin incisions 7 cm in length were made in the dorsal region of each dog. Dogs were put to death at 4, 9, 16, and 23 days postoperatively and the bronchial anastomoses and skin wounds were evaluated by breaking strength measurements. Bronchus and skin breaking strength increased with time in both groups. Bronchus breaking strength was similar in the two groups at day 4 and day 9. However, by day 23 bronchus breaking strength was significantly higher in Group I (p < 0.001). Skin breaking strength was significantly higher in Group 1 on days 9 and 16 (p < 0.005) and on day 23 (p < 0.001). Our results suggest that low-dose methylprednisolone and azathioprine significantly affect the breaking strength of both bronchial anastomoses and healing skin incisions following canine lung autotransplantation.

Bronchial complications are a major problem following lung transplantation. Ischemia of the donor bronchus is an important underlying cause of these complications. We have previously demonstrated the ability of an omental pedicle flap to revascularize the donor bronchus as early as 4 days following canine left lung reimplantation. In the present study, omental pedicle wraps markedly improved the healing of the bronchial anastomoses 23 days following canine left lung reimplantation. In dogs in which omentum was used (n = 6), the bronchial mucosal appearance was more normal and the degree of bronchostenosis was significantly less when compared with dogs without omental flaps (n = 10). These experiments suggest that the use of omental pedicle flaps may significantly reduce bronchial complications following lung transplantation.