Transbronchial needle aspiration : a systematic review on predictors of a successful aspirate

Background: Transbronchial needle aspiration (TBNA) is a safe and useful sampling technique for the diagnosis of mediastinal adenopathies/masses, but its accuracy seems to be influenced by selected clinical and procedural aspects. Objectives: We performed a systematic review to identify the main predictors of a successful transbronchial aspirate according to different clinical settings. Methods: We searched Medline and Embase for all studies evaluating predictors of TBNA diagnostic yield, published up to February 2012. Two authors reviewed all titles/abstracts and retrieved the full text of articles that are potentially relevant to identify studies according to predefined selection criteria. The methodological quality of studies was assessed through the revised Quality Assessment of Diagnostic Accuracy Studies tool. Evidence synthesis was graded according to overall number of studies, patients involved and methodological features. Results: Fifty-three studies, involving more than 8,000 patients and evaluating 23 potential predictive factors, were included. Major predictors in an unselected population, as well as in patients with suspected/known lung cancer, included lymph node size (short axis length ≥2 cm), presence of abnormal endoscopic findings, subcarinal and right paratracheal location, and the use of histological needle by an experienced bronchoscopist. Stage I and sampling of more than one lymph node stations were the only predictors of a successful TBNA result in patients with suspected sarcoidosis. Conclusions: The diagnostic yield of TBNA depends on selected clinical and procedural features. Knowledge of factors that predict a positive TBNA result may help optimize the diagnostic success of the procedure in different clinical settings.