The diagnostic contribution of bronchoalveolar lavage to lung cryo-transbronchial biopsy in interstitial lung diseases

In interstitial lung diseases (ILDs), achieving a definitive diagnosis based on clinical and radiological findings alone can be challenging, often necessitating lung biopsy. Considering the high risk of complications associated with surgical biopsy, transbronchial cryobiopsy (c-TBB) has emerged as a less invasive alternative. However, due to its more limited histopathological yield compared to surgical biopsy, additional diagnostic methods may be required. In this study, we aimed to evaluate the diagnostic contribution of bronchoalveolar lavage (BAL) performed simultaneously with c-TBB. This retrospective, cross-sectional study was conducted at a tertiary training and research hospital between November 2023 and June 2024. A total of 127 patients with a preliminary diagnosis of ILD who underwent simultaneous diagnostic BAL and c-TBB were included. Patients’ clinical and radiological features, BAL and c-TBB findings, and any complications were recorded. Final diagnoses for all cases were established through multidisciplinary discussion (MDD). Of the included patients, 51.2% (n = 65) were male, with a mean age of 60 years (range: 19–79). Histopathological diagnosis was achieved with c-TBB in 76.4% of cases (n = 97), with the most common diagnoses being fibrotic NSIP (31.5%, n = 40) and non-fibrotic NSIP (12.6%, n = 16). Among 30 patients without a definitive diagnosis by c-TBB, 22 received a diagnosis through MDD. The contribution rate of BAL in patients with a histopathological diagnosis was 30.9% (n = 30), and 46.6% (n = 14) in those without a histopathological diagnosis. Overall, BAL contributed to the multidisciplinary diagnosis in 34.6% of all patients (n = 44), with a statistically significant difference between groups (p = 0.04); the highest contribution was observed in the non-fibrotic HP group (p = 0.01). In cases without a histopathological diagnosis, BAL provided the highest contribution in the fibrotic HP group. No adverse events related to BAL were observed, while complications occurred in 42.5% of patients undergoing c-TBB. The most common complications were hemorrhage (mostly mild to moderate), pneumothorax (17.3%, with tube thoracostomy performed in 11.8% of all cases), and mild respiratory failure (6.3%), with no life-threatening complications recorded. Our study demonstrates that the combined use of BAL and c-TBB provides significant added value to the multidisciplinary diagnostic process in ILDs. Performing simultaneous BAL in patients undergoing c-TBB can be considered a safe and effective approach that enhances diagnostic yield in the multidisciplinary evaluation of ILDs.