Acute Cellular Rejection in Lung Transplant: Can the Bronchoscopist Assess Transbronchial Biopsy Sample Adequacy?

Abstract

<h3>Purpose</h3> Acute cellular rejection (ACR) is a histopathologic diagnosis made by assessment of transbronchial biopsies (TBBX). Consensus guidelines recommend a minimum of 5 alveolated samples for histologic adequacy; it is not uncommon for samples to be inadequate for diagnosis. This study was designed to determine what factors impact the recovery of adequate specimens for ACR grading, as well as explore discrepancies in "sample calling" between the pathologist & bronchoscopist. <h3>Methods</h3> Observational, single center study including retrospective chart review of 142 bronchoscopies with TBBX performed on 128 lung transplant recipients (LTRs) who underwent surveillance bronchoscopy between May 2017 & May 2018. For the purpose of our study we defined inadequate samples as < 4 fragments of alveolated tissue as determined by the pathologist. Data collected includes demographic data of the LTR, sample, & procedural characteristics, as well as procedural outcomes. Logistic regression was used to determine the association between LTR, sample, & procedural characteristics & inadequate sampling. <h3>Results</h3> Of 142 TBBX procedures, 22 (15.5%), resulted in inadequate sampling. Of note, pathologists called less sample fragments than bronchoscopists 70% of the time. Characteristics associated with inadequate sampling included both LTR & procedural characteristics (Table 1 & 2). <h3>Conclusion</h3> Bronchoscopists may overestimate the number of total fragments obtained compared with pathologists. Both demographic & procedure characteristics may aid in identifying LTRs at higher risk for inadequate sampling during TBBx.