Diagnostic properties of transbronchial biopsy in lung transplant recipients who require mechanical ventilation

Introduction: Bronchoscopy with transbronchial biopsy (TBBx) and bronchbalveolar lavage is useful and safe for diagnosing acute rejection and infection in lung transplant recipients. However, its role is less well defined, in determining the etiology of allograft dysfunction in the setting of respiratory failure necessitating mechanical ventilation. Methods: We retrospectively identified 41 mechanically ventilated patients with respiratory failure in whom 42 TBBx were followed within a 10 day period by surgical lung biopsy (SLBx) to determine the sensitivity, specificity, and positive and negative predictive values of TBBx compared with SLBx. Results: The sensitivity, specificity, and positive and negative predictive values of TBBx for all episodes of acute rejection and for significant episodes of acute cellular rejection were 53.3% and 36.0%; 91.7% and 94.1%; 94.1% and 90.0%; 44.0% and 50.0%, respectively. A significantly higher histologic grade was noted on SLBx compared with TBBx specimens obtained within a 10-day period (2.39 +/- 1.02 vs 0.97 +/- 0.11, p less than or equal to 0.0001). Performing SLBx in this setting increased histopathologic diagnoses by 33% and resulted in treatment changes in 15 of 41 (37%) patients. Conclusions: Transbronchial biopsy has low sensitivity, high specificity, and high positive predictive value for diagnosing acute rejection. We found a significant tendency for TBBx to underestimate the presence and severity of clinically significant grades of rejection while simultaneously overestimating the presence of clinically insignificant rejection. Adding SLBx is valuable in lung transplant recipients with respiratory failure who require mechanical ventilation.