Proposal for Simplified Endoscopic Standardized Grading of Central Airway Complications After Lung Transplantation According to the Long-Term Prognosis Value of the Current MDS Classification

Abstract

<h3>Purpose</h3> The MDS classification (<i>i.e.</i> Macroscopic aspect, Diameter, Suture) allows an endoscopic grading of bronchial complications after lung transplantation. We aimed to determine the long-term prognosis value of the MDS airway evaluation after lung transplant and to propose a new organization in prognostic stage of the MDS classification. <h3>Methods</h3> We performed a retrospective monocentric cohort study of the consecutive patients who underwent a single or double lung transplant between the January 2015 and December 2021. We analyzed the prospectively evaluated MDS status at day 7, 28 and 90 after transplantation and the long term follow-up. Analyzed outomes were overall survival (OS), chronic lung allograft dysfunction (CLAD) and airways complications (AC) defined by reoperation or rigid bronchoscopy requirement. <h3>Results</h3> During the study period 221 lung transplants were performed. 437 bronchial anastomoses were analyzed at day 7, 378 at day 28 and 336 at day 90. At day 7, patients with extremely severe and extensive necrosis of the bronchial mucosa (M3d) presented worse OS (p<0.01); While extensive ischemic or necrosis bronchial mucosa (M3c) was associated with AC (p<0.01). At day 28, patients with bronchial mucosa necrosis distal to the anastomosis (M3b, 3c and 3d) presented a worse OS (all p≤0.01) and AC (all p<0,01). At day 90, patients who still presented M3c presented worsened OS (p<0.01) and increased risk of AC (p<0.01). Separate analysis of patients with M3b, c and d (at day 28 and 90) showed similar relationship with OS, CLAD and AC (all p<0.01); as far as patients with M0 and M1 had the same prognosis in terms of OS (all p=NS), CLAD and AC (all p=NS), it was the same for M2 and M3a (all p=NS). Therefore, we have reorganized the MDS classification in 3 stages: G1 for M0/M1 a, b, c, d; G2 for M2 a, d, c, d/M3 a; G3 for M3b, c, d. We have compared the 3 groups of patients with G1 as reference. Stage G3 at day 7 was associated with AC (p<0.05) while at days 28 and 90 it was associated with OS, AC and CLAD (all p<0.05) <h3>Conclusion</h3> The endoscopic MDS grading system can be simplified into 3 groups providing prognostic risk stratification of OS, AC and CLAD development after lung transplantation.