The backflow from the pulmonary circulation for identification of the aortic origin of the bronchial arteries in experimental left single lung transplantation

Topographic anatomy of bronchial arteries in the pig: a corrosion cast study

The anatomy of porcine bronchial circulation has not been fully described. The purpose of this study was to investigate the extrapulmonary topographic anatomy of bronchial arteries in pig. Ten pigs weighing 15-25 kg were studied. Between one and four bronchial arteries were found in each pig. The bronchoesophageal artery (BEA), tracheobronchial artery (TBA), inferior bronchial artery (IBA) and accessory bronchial artery (ABA) were present in 10/10, 8/10, 6/10 and 2/10 animals, respectively. The trunk of BEA had a diameter of about 3 mm, a length of 1-7 mm, and originated from the anterior and medial aspect of the descending thoracic aorta at the level between the 2nd and 4th thoracic vertebrae (T2-T4) in all animals. The extrapulmonary topographic anatomy of bronchial arteries in pigs exhibits similarities to that of humans. BEA is the main blood supplier of the porcine tracheobronchial tree with a relatively constant location of origin and a sufficient size for anastomosis. These characteristics render BEA the ideal vessel for bronchial revascularization in pigs.

Bronchial artery revascularization restores peribronchial tissue oxygenation after lung transplantation

With the interruption of the bronchial arteries after lung transplantation, nutritive support is dependent on collateral flow by the pulmonary arteries with desaturated venous blood. Consequently, oxygen deficiency of the peribronchial and dependent lung tissue may occur. Using a canine model for left lung transplantation, we investigated hypoxic peribronchial tissue after conventional lung transplantation and demonstrated restitution of tissue oxygenation after transplantation with bronchial artery revascularization (BAR) (BAR group: Po2 120.4 +/- 28.7 mm Hg; control group Po2 6.8 +/- 2.8; p < 0.001). BAR in lung transplantation protects peribronchial tissue of the transplanted graft from hypoxia in the early phase after reperfusion.

Bronchial artery revascularization affects graft recovery after lung transplantation

Restitution of bronchial artery circulation might alter ischemia- reperfusion injury and improve organ function after lung transplantation. Weight-matched dogs underwent a left lung allotransplantation either with bronchial artery revascularization (BAR; n = 6) or as conventional lung transplantation (LTX; n = 6), to evaluate effects of BAR on lung cell function over a period of 5 h postischemically. Lactate dehydrogenase (LDH) and marker enzymes for pneumocytes type I (carboxypeptidase M [CPM], pneumocytes type II (alkaline phosphatase [AP]), and pulmonary endothelium (angiotensin-converting-enzyme [ACE]) were determined from bronchoalveolar lavage fluid. Donor lungs were preserved with Euro-Collins solution. Total ischemic time was kept at 6 h. CPM and LDH activities were significantly higher in both groups at 2 h and 4 h of reperfusion compared with control dogs (p < 0.01). AP and ACE activities in lavage after 2 h of reperfusion were significantly elevated in animals that underwent LTX (AP: 60 +/- 28 IU/L; ACE: 1.39 +/- 1.13 IU/L) compared with animals with BAR (AP: 33 +/- 29 IU/L; ACE: 0.35 +/- 0.6 IU/L; p < 0.05) and with control animals (AP: 13.58 +/- 11.0 IU/L; ACE: 0.06 +/- 0.14 IU/L; p < 0.01). According to these results, BAR protects pulmonary endothelium and type II pneumocytes in the early phase after lung transplantation and might have consequences for lung tissue in the long term.

The porcine bronchial artery: surgical and angiographic anatomy

The pig is often used in experimental studies on the significance of bronchial artery circulation, but the anatomy of this artery is only poorly described. The purpose of this study was to improve the anatomical basis for experimental studies on the porcine bronchial artery circulation. The origin of the artery from the aorta is described in 32 pigs. Heart-lung blocks were perfused with saline and removed in 16 pigs, and the broncho-oesophageal orifice was identified and cannulated. In these 16 specimens the intrapulmonary ramification was studied by angiography, and the extrapulmonary distribution and supply area by injection of Evans Blue. The broncho-oesophageal artery originated from the aorta as a single trunk in 91%. Angiography showed that each principal bronchus was accompanied by 2 bronchial artery branches far into the lung parenchyma. The central branching pattern of the artery between the aorta and the principal bronchi was divided into 3 subtypes. Evans Blue showed communication with the whole mediastinum. The anatomical relations are described. It is concluded that the broncho-oesophageal artery divides to follow each bronchus with 2 bronchial branches. A nomenclature for these branches is suggested. The pig anatomy is suited for experimental investigations on the bronchial circulation.