Fibrinogen/thrombin-based collagen fleece (TachoComb(R)) promotes regeneration in pulmonary arterial injury.

OBJECTIVES To repair unexpected damage of the pulmonary artery (PA) during thoracic surgery, fibrinogen/thrombin-based collagen fleece (TachoComb(®) [TC]) can be applied as a haemostatic material. The progression of vessel restoration with TC has not been elucidated. In this study, we investigate details of the healing process with TC after PA injury using a canine model. METHODS Left thoracotomy was performed on female beagles under general anaesthesia. PA injury was induced and repaired using TC. Repair sites were histologically evaluated 2, 4 and 8 weeks after surgery (n = 3 in each group). RESULTS Haemostasis of PA injury was achieved promptly after TC application. After surgery, no bleeding was found in the thoracic cavity, and no repair sites revealed stenosis, thrombi or false aneurism formation. Two weeks after surgery, inflammatory cells had infiltrated around the vascular defect, and vascular endothelium had regenerated on the innermost surface of TC applied to the defect. At Week 4, elastic and smooth muscle fibres had begun to extend into the defect between the endothelial layer and collagen fleece. By Week 8, elastic fibres and smooth muscle had completely regenerated in the medial layer. The adventitial layer had also fully regenerated. CONCLUSIONS Haemostasis of injured PA using TC was safe and reliable. TC provided a mechanical scaffold on which vascular regeneration occurred. Three layers reconstructed in the PA defect were identical to those in normal structures.