J Thorac Cardiovasc Surg 1995;109:815-817
© 1995 Mosby, Inc.
Airway complications after lung transplantation: Is there a left-sided predilection?
Motoshi Takao, MDa,
Syoji Namikawa, MDa,
Hiroshi Yuasa, MDa,
Isao Yada, MDa,
Minoru Kusagawa, MDa,
Tim Higenbottam, FRCPb,
John Wallwork, FRCSc
Department of Thoracic and Cardiovascular Surgery
Mie University School of Medicine
Tsu, Japana
Department of Respiratory Physiologya
Transplant Unitb
Papworth Hospital
Cambridge, United Kingdom
To the Editor:
We read with interest the article by Griffith and associates 
1 that was published in this Journal. They have clearly shown that most complications of airway anastomoses after lung transplantation can be avoided by the refinement of surgical techniques(Table I, J THORAC CARDIOVASC SURG 1994;107:746). Although the etiology of impaired bronchial healing after lung transplantation is multifactorial, bronchial ischemia seems to be the primary cause. 2 In this series all seven patients with severe bronchial stenoses after bilateral lung transplantation had stenotic lesions of the left bronchus (three had bilateral stenoses). These patients were treated with endobronchial stents. Two patients had bronchial stenosis necessitating stenting after single left lung transplantations; by contrast, no bronchial stenoses occurred after single right lung transplantation (Table II, J THORAC CARDIOVASC SURG 1994;107:746). Colt and associates 3 also have reported that all ten patients in whom stenosis developed after double lung transplantation demonstrated abnormalities at the level of the left main bronchial anastomosis (three had bilateral stenoses).
How can the prevalence of complications in the left main bronchus be explained? It may be related to the longer preservation time of the left lung, which is transplanted after the right lung in cases of bilateral lung transplantation The blood supply to the donor bronchi, which is a retrograde pulmonary arterial circulation via an intrapulmonary connection between the bronchial arteries and pulmonary arteries, is critical after lung transplantation. 4,5 Another hypothesis is that such a stenosis may be related to the length of the recipient main bronchus, its anatomic structure, and differences in vascularization between the left and right main bronchi. 6,7
We measured bronchial mucosal blood flow using laser Doppler flowmetry (ALF 2100, Advance Co Ltd., Tokyo, Japan) in 23 patients not undergoing transplantation, 19 patients having heart-lung transplantation, and two patients having sequential double lung transplantation. The time after transplantation ranged from 1 to 55 months. No ischemic airway complications were observed during this period.
The average values of the bronchial mucosal blood flow (mean ± standard deviation) were 40.2 ± 14.6 (main carina), 35.2 ± 17.4 (left main bronchial carina), and 33.3 ± 17.4 ml/min per 100 gm tissue (right main bronchial carina) in patients not undergoing transplantation and 37.6 ± 16.5 (main carina), 29.0 ± 17.8 (left main bronchial carina), and 37.4 ± 17.0 ml/min per 100 gm tissue (right main bronchial carina) in transplant recipients. The bronchial mucosal blood flow was lower in the left bronchus than in the right bronchus by 0.66 ± 7.7 ml/min per 100 gm tissue in patients not undergoing transplantation (Fig. 1) and by 9.5 ± 14.7 ml/min per 100 gm tissue in transplant recipients (Fig. 2). The differences were greatest in transplant recipients who experienced complications such as pneumonia or obliterative bronchiolitis. In three of seven transplant recipients with pneumonia and in four of eleven transplant recipients with obliterative bronchiolitis, the bronchial mucosal blood flow was lower in the left bronchus than in the right bronchus by 15.4 ml/min per 100 gm tissue and more (a 2 standard deviation difference existed in the bronchial mucosal blood flows between the right and left main bronchi in patients not undergoing transplantation) (Fig. 2).
View larger version (30K):
[in this window]
[in a new window]
|
Fig. 1. Bronchial mucosal blood flow at the level of the right (horizontal axis) and left (vertical axis) main bronchi in patients not undergoing transplantation. They are highly correlated; left = 5.4488+0.81631 right, R = 0.806.
|
|
Although the tracheal anastomoses that were performed in patients who underwent heart-lung transplantations may have been supplied via collaterals from the coronary arteries, it is interesting that the bronchial mucosal blood flow of the left main bronchus tended to be lower than that of the right main bronchus in transplant recipients with pneumonia and obliterative bronchiolitis. This lower bronchial mucosal blood flow at the left main bronchus might have been related to the prevalence of abnormal bronchial healing associated with the left bronchus in postoperative lung transplant recipients with pneumonia or obliterative bronchiolitis, whose airway anastomoses were performed without collateral flow from the coronary arteries.
References
-
Griffith BP, Magee MJ, Gonzales IF, et al. Anastomotic pitfalls in lung transplantation. J THORAC CARDIOVASC SURG 1994;107:743-54.[Abstract/Free Full Text]
-
Mills NL, Boyd AD, Gheranpong C. The significance of bronchial circulation in lung transplantation. J THORAC CARDIOVASC SURG 1970;60:866-78.[Medline]
-
Colt HC, Janssen JP, Dumon JF, Noirclerc MJ. Endoscopic management of bronchial stenosis after double lung transplantation. Chest 1992;102:10-6.[Abstract/Free Full Text]
-
Siegelmann SS, Hagstrom JWC, Koerner SK, Veith FJ. Restoration of bronchial artery circulation after canine lung allotransplantation. J THORAC CARDIOVASC SURG 1977;73:792-5.[Abstract]
-
Balie EM, Minshall D, Dodek PM, Pare PD. Blood flow to the trachea and bronchi: the pulmonary contribution. J Appl Physiol 1994;76:2063-9.[Abstract/Free Full Text]
-
Pinsker KL, Koerner SK, Kamholz SL, Hargstrom JWC, Veith FJ. Effect of donor bronchial length on healing: a canine model to evaluate bronchial anastomotic problems in lung transplantation. J THORAC CARDIOVASC SURG 1979;77:669-73.[Abstract]
-
Schreinemarkers HH, Weder W, Miyoshi S, et al. Direct revascularization of bronchial arteries for lung transplantation: an anatomic study. Ann Thorac Surg 1990;49:44-54.[Abstract]
), blood flow of both sides is highly correlated; left = 0.18797+0.92965 right, R = 0.879, whereas blood flow is significantly reduced in patients during acute rejection. In most patients with pneumonia or obliterative bronchiolitis (
), blood flow is lower in the left bronchi than in the right bronchi, and there is no correlation between the sides; left = -1.1308+0.73173 right, R = 0.306.