Successful bronchial revascularization in experimental single lung transplantation

Abstract

It is the purpose of this paper to report our experience with bronchial artery revascularization in an experimental model of single lung transplantation in swine. Thirty-three large white pigs weighing 20-40 kg underwent left lung allotransplantation. In 24 animals, bronchial artery revascularization was attempted by anastomizing the aortic patch containing the bronchial artery orifice with the recipient descending aorta. Eight survivors were put to death on postoperative days 11-15; five animals were put to death or died on postoperative days 2-9; the other animals died intra-operatively or within a few hours. Preservation of left bronchial vascularization was achieved in all cases attempted, as documented by post-mortem injection of dye (methylene blue) or contrast medium. Five of the 8 animals surviving for 11-15 days showed diffuse graft hepatization, associated with diffuse vascular thrombosis. Whether this was caused by damage to the endothelium due to poor graft preservation or by rejection was unclear. In animals surviving for 11-15 days without gross lung pathology, the anastomosis and bronchial mucosa were completely normal; in contrast, bronchial ischaemic changes were found in nonrevascularized animals and in survivors with graft hepatization. Our experience confirms that re-anastomosis of the bronchial arteries can prevent bronchial healing problems in single lung transplantation. The pig is an ideal model for these experiments since the bronchial arteries have a constant common aortic origin, allowing easy identification and preservation of left bronchial vascularization.

The Backflow from the Pulmonary Circulation for Identification of the Aortic Origin of the Bronchial Arteries in Experimental Left Single Lung Transplantation

“…In previous studies at our laboratory, we accumulated a quite large experience with left lung bronchial revascularization in a swine model [20], The swine breed provided to our laboratory (large white) is very suitable for this purpose since the bronchial arteries have always a common aortic origin, which is very easy to identify. In those experiments we were able to prepare an aortic patch, carrying the left bronchus systemic circulation which was anastomosed to the descending aorta, after atrial, pulmonary artery and bronchial anas- [18] and direction o f blood flow in normal conditions.…”

The porcine bronchial artery. Anastomoses with oesophageal, coronary and intercostal arteries

“…This is the equivalent of the human bronchial artery(-ies). The porcine bronchial artery is easy to identify and control, which is an advantage (Nazari et al 1990). However, if physiological studies are undertaken, not only the direct supply by the bronchial artery, but also the systemic collateral blood flow must be considered (Baile et al 1992).…”

“…The bronchial arteries are systemic arteries, providing oxygenated blood for the bronchi and extracardiac mediastinal structures (including the oesophagus, lymph nodes and the sympathetic and parasympathetic nervous system) (Cauldwell et al 1948 ;Deffebach et al 1987 ;Christensen & Mousing, 1992). The bronchial arteries have received increasing attention in human lung transplantation (Couraud et al 1992 ;Daly & McGregor, 1994 ;Baudet et al 1996 ;Nørgaard et al 1997 ;Pettersson et al 1997) as well as experimentally (Nazari et al 1990 ;Aoki et al 1991 ;Laks et al 1991 ;al Dossari et al 1994), after bronchial Correspondence to Dr John Gade, Department of Cardiothoracic Surgery RT, 2152, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen Ø, Denmark. Tel.…”

“…From a theoretical point of view, often based on animal studies, systemic oxygenated blood for the bronchi should avoid or reduce complications in lung transplantation related to bronchial ischaemia, i.e. poor healing (Nazari et al 1990), infection (Charan et al 1985) and obliterative bronchiolitis (Yousem et al 1990 ;Baudet et al 1996). However, the role of BAR is controversial (Patterson, 1993) and the physiological role of the bronchial arteries in lung transplantation is difficult to establish by clinical studies alone.…”

“…The pig is a widely used animal for experimental research in lung transplantation (Nazari et al 1990 ;Aoki et al 1991 ;Laks et al 1991 ;al Dossari et al 1994). In most cases the porcine bronchial artery has a single origin from the aorta (Calka, 1975 ;Gade et al 1999).…”