Progression pattern of restrictive allograft syndrome after lung transplantation

Background: Restrictive allograft syndrome (RAS) is a novel form of chronic lung allograft dysfunction after lung transplantation. RAS is characterized by restrictive physiology and peripheral lung fibrosis. The purpose of the study is to analyze progression patterns of RAS.

Methods: Clinical information, pulmonary function test results and radiographic findings were reviewed for 25 RAS patients who received bilateral lung or heart-lung transplantation between January 2004 and December 2009.

Results: Average time from transplantation to RAS onset was 647 ± 544 (mean ± SD) days; RAS onset to end of observation (death or re-transplantation) was 490 ± 417 days. RAS patients had 1 to 4 episodes of acute exacerbation (2.48 ± 0.82 episodes/patient) that accompanied acute respiratory deterioration or distress, a sudden drop in pulmonary function, evidence of diffuse alveolar damage (DAD) on biopsies, and patchy or diffuse ground-glass opacities (GGO) with occasional consolidation on computed tomography scan. Patients were most frequently managed by high-dose steroid in combination with empirical antibiotics, with uncertain efficacy. Acute exacerbation was followed by an interval during which resolution of GGO and progression of consolidation, interstitial reticular shadows and traction bronchiectasis were frequently observed. The interval between episodes of acute exacerbation was 238 ± 165 days. In 21 patients, the last episode of acute exacerbation led to death or urgent retransplantation.

Conclusions: RAS shows a "stair-step" pattern of progression. Acute lung injury represented by DAD and GGO is followed by an interval period during which graft fibrosis often progresses.