Transition from BOS to RAS impairs prognosis after lung transplantation-CLAD subtype analysis by CT volumetry.

BACKGROUND: Chronic lung allograft dysfunction (CLAD), subclassified into bronchiolitis obliterans syndrome (BOS) or restrictive allograft syndrome (RAS), limits survival after lung transplantation. Information concerning transition from BOS to RAS is limited. We aimed to characterize the lung volume change after BOS diagnosis by computed tomography (CT) volumetry and to determine the incidence, risk factors and clinical significance of BOS to RAS transition. METHODS: CT volumetry measurements were performed from 63 patients with CLAD initially classified as BOS by CT volumetry. BOS patients with lung volume remaining >85% of baseline were classified as persistent BOS, whereas BOS patients whose lung volume permanently decreased to ≤85% of baseline were classified as BOS to RAS transition. RESULTS: During follow-up (median 9.8 years) eight patients (12.7%) were classified as BOS to RAS transition, which decreased recipient (p = 0.004) and graft survival (p = 0.020) in comparison to patients with persistent BOS. Opacities on chest imaging preceded BOS to RAS transition in 88% of patients. Opacities on chest imaging at BOS diagnosis and early CLAD diagnosis after transplantation were risk factors for transition. CONCLUSION: Based on lung volume decrease measured by CT volumetry, a small proportion of BOS patients transitioned to RAS which had an adverse effect on recipient and graft survival.

Chronic lung allograft dysfunction subtype analysis by computed tomography volumetry.

BACKGROUND: Chronic lung allograft dysfunction (CLAD) limits long-term survival after lung transplantation. Of the two subtypes, restrictive allograft syndrome (RAS) is characterized by a larger lung volume decrease and worse prognosis than bronchiolitis obliterans syndrome (BOS). We used computed tomography (CT) volumetry to classify CLAD subtypes and determined their clinical impact. METHODS: Adult primary lung transplants performed 2003-2015 (n = 167) were retrospectively evaluated for CLAD and subclassified with CT volumetry. Lung volume decrease of < 15% from baseline resulted in BOSCT-vol and ≥15% resulted in RASCT-vol diagnosis. Clinical impact of CLAD subtypes was defined, and the prognostic value of different lung function, radiological, and lung volume parameters present at the time of CLAD diagnosis were compared. RESULTS: CLAD affected 43% of patients and was classified with CT volumetry as BOSCT-vol in 89% and RASCT-vol in 11%. Median graft survival estimate in RASCT-vol was significantly decreased compared to BOSCT-vol (1.6 vs. 9.7 years, P = .038). At CLAD onset, RASCT-vol diagnosis (P = .05), increased lung density (P = .007), and more severe FEV1 (P = .004) decline from baseline, increased graft loss risk in multivariate analysis. CONCLUSIONS: CT volumetry serves to identify lung transplant patients with a poor clinical outcome but should be validated in prospective trials.

Incidence and impact of chronic lung allograft dysfunction after lung transplantation - single-center 14-year experience.

Objectives. Lung transplantation remains the only available treatment option for many end-stage lung diseases. We evaluated our long-term lung transplantation results and the impact of chronic lung allograft dysfunction (CLAD). Design. Adult de novo lung transplants (2003-2015, n=175) in a nationwide single transplant center were retrospectively analyzed. Kaplan-Meier survival and Cox regression analysis were used to evaluate the effect of CLAD. Results. Recipient and graft 1-, 5- and 10-year survival estimates were 94%, 79% and 64%, and 93%, 75% and 59%, respectively. CLAD affected 43% of patients at a median of 2.3 years after transplantation, and impaired recipient (p = .03) and graft survival (p = .001) with the most advanced CLAD stage, and restrictive CLAD phenotype, resulting in worst graft survival. CLAD was the primary cause of death in 54% of all patients, and in 80% of patients with an established CLAD diagnosis. CLAD, high-risk cytomegalovirus serostatus, and recipient preoperative sensitization increased graft loss hazard ratio. CLAD was the only significant investigated risk factor for graft loss in multivariate regression analysis. Conclusions. Although very favourable lung transplant patient long-term survival was achieved, CLAD significantly impaired recipient and graft survival. Identification of risk factors and therapeutic options for CLAD may further improve lung transplantation results.