Restrictive allograft syndrome (RAS): a novel form of chronic lung allograft dysfunction

J Heart Lung Transplant. 2011 Jul;30(7):735-42. doi: 10.1016/j.healun.2011.01.712. Epub 2011 Mar 17.

Abstract

Background: Bronchiolitis obliterans syndrome (BOS) with small-airway pathology and obstructive pulmonary physiology may not be the only form of chronic lung allograft dysfunction (CLAD) after lung transplantation. Characteristics of a form of CLAD consisting of restrictive functional changes involving peripheral lung pathology were investigated.

Methods: Patients who received bilateral lung transplantation from 1996 to 2009 were retrospectively analyzed. Baseline pulmonary function was taken as the time of peak forced expiratory volume in 1 second (FEV(1)). CLAD was defined as irreversible decline in FEV(1) < 80% baseline. The most accurate threshold to predict irreversible decline in total lung capacity and thus restrictive functional change was at 90% baseline. Restrictive allograft syndrome (RAS) was defined as CLAD meeting this threshold. BOS was defined as CLAD without RAS. To estimate the effect on survival, Cox proportional hazards models and Kaplan-Meier analyses were used.

Results: Among 468 patients, CLAD developed in 156; of those, 47 (30%) showed the RAS phenotype. Compared with the 109 BOS patients, RAS patients showed significant computed tomography findings of interstitial lung disease (p < 0.0001). Prevalence of RAS was approximately 25% to 35% of all CLAD over time. Patient survival of RAS was significantly worse than BOS after CLAD onset (median survival, 541 vs 1,421 days; p = 0.0003). The RAS phenotype was the most significant risk factor of death among other variables after CLAD onset (hazard ratio, 1.60; confidential interval, 1.23-2.07).

Conclusions: RAS is a novel form of CLAD that exhibits characteristics of peripheral lung fibrosis and significantly affects survival of lung transplant patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analysis of Variance
  • Bronchiolitis Obliterans / etiology
  • Bronchiolitis Obliterans / mortality
  • Bronchiolitis Obliterans / physiopathology
  • Chronic Disease
  • Female
  • Follow-Up Studies
  • Forced Expiratory Volume / physiology
  • Heart-Lung Transplantation / adverse effects
  • Heart-Lung Transplantation / mortality
  • Heart-Lung Transplantation / physiology
  • Humans
  • Lung Transplantation / adverse effects*
  • Male
  • Middle Aged
  • Phenotype
  • Primary Graft Dysfunction / etiology*
  • Primary Graft Dysfunction / mortality
  • Primary Graft Dysfunction / physiopathology*
  • Retrospective Studies
  • Risk Factors
  • Survival Rate
  • Syndrome
  • Total Lung Capacity / physiology
  • Transplantation, Homologous
  • Treatment Outcome