Spectrum of findings on ventilation‒perfusion lung scintigraphy after lung transplantation and association with outcomes

Abstract

Air trapping (AT) is one of the hallmarks of allograft dysfunction after lung transplantation (LT). Inert gas‒based ventilation‒perfusion (VQ) lung scintigraphy has excellent sensitivity in the detection of AT. We reviewed the charts of patients who underwent single or double LT between January 2012 and December 2014 (N = 193). Patients without a VQ scintigraphy at the first annual visit (n = 16) and those who did not survive till 1 year (n = 26) were excluded (final n = 151, mean age = 55.8 [SD =14] years, male = 85, female = 66). VQ scintigraphy was independently reviewed and reconciled for the presence and severity of AT by 2 investigators blinded to the clinical data (D.F.P. and D.M.). A 3-year post-transplant survival was the primary end-point. AT was common (n = 73, 48.3%). Patients with obstructive lung diseases as the underlying diagnosis (adjusted odds ratio [OR], 4.36, 95% CI: 1.64‒11.6; p = 0.003) and those with lower body mass index (BMI) (BMI < 25 kg/m2 and 25‒30 kg/m2; p < 0.001) had an increased risk of developing AT in the allograft. The presence of AT (adjusted OR, 2.33, 95% CI: 1.01‒5.36; p = 0.04) and peak forced expiratory volume in 1 sec (FEV1) <60% predicted during the first year after LT were independently associated with 3-year mortality. The association of AT with post-transplant mortality was the strongest among patients with BMI <30 kg/m2 and peak FEV1 <60% predicted. The finding of AT on VQ scintigraphy at the first annual visit after LT is independently associated with worse post-transplant mortality. The sub-group of patients who fail to achieve a peak FEV1 of 60% predicted during the first year after LT appears to be the key driver of this association.