A new endoscopic standardized grading system for macroscopic central airway complications following lung transplantation: the MDS classification

After lung transplant, between 9 and 13% of bronchial anastomoses develop complications severe enough to warrant therapeutic intervention. These complications include stenosis, dehiscence, granulation tissue, bronchomalacia and fistula. Most of these have already been included in a classification or another, but none of these have been universally accepted. Moreover, no grading system has integrated all of these complications. The Groupe Transplantation (GT) (Transplant Group), from the Societe de Pneumologie de Langue Francaise (SPLF) [French Language Pulmonology Society], maintains a prospective national registry of lung transplants performed in France. The GT has mandated the Groupe d'Endoscopie de Langue Francaise (GELF), also from the SPLF, to develop an endoscopic classification, in order to describe the macroscopic aspect of the bronchial anastomoses, and downhill airways, using a standardized and exhaustive grading system. An endoscopic classification that would take into account the three major aspects of the description of bronchial anastomoses was elaborated. The first parameter is the macroscopic aspect (M), the second, the diameter (D) of the anastomosis and the third, the sutures (S) of the anastomosis. This classification was then submitted to expert bronchoscopists from nine centres, responsible for lung transplants in France, for their opinion, using a five-item questionnaire, according to the Delphi methodology. After the first round of consultation, all experts (100%) agreed on Questions 1 and 4. Answers were positive for Questions 2 (59%), 3 (56.25%) and 5 (70%). A modified classification, incorporating propositions from the first round, was then submitted. This second round allowed a consensus to be reached between all experts: the MDS classification. Each parameter (M, D and S) can be classified from 0 to 3. For M and D, it is possible to determine the extent of abnormalities downhill from the anastomosis into four subgroups (a, b, c or d). For S, the localization of abnormalities can be divided between two subgroups (e and f). The MDS classification, established by a consensus of French experts in bronchoscopy, could represent a standardized, universally acceptable system to describe central airway complications after lung transplant.