BAL Contribution to Lung Cryo-TBB in ILD

Diagnostic Contribution of Bronchoalveolar Lavage to Lung Cryotransbronchial Biopsy in Interstitial Lung Diseases

The goal of this observational study is to evaluate whether performing bronchoalveolar lavage (BAL) simultaneously with transbronchial lung cryobiopsy (c-TBB) can improve diagnostic yield in adult patients with suspected interstitial lung disease (ILD).

The main questions it aims to answer are:

• Does the addition of BAL to c-TBB increase the overall diagnostic accuracy in ILD patients?
• Can the combination of BAL and c-TBB reduce the need for surgical lung biopsy in the diagnostic process of ILD?

If there is a comparison group: Researchers will compare patients diagnosed by c-TBB alone to those evaluated with both c-TBB and BAL to see if BAL provides additional diagnostic value, especially in cases where histopathological findings from c-TBB are inconclusive.

Participants will:

Undergo transbronchial lung cryobiopsy (c-TBB) under general anesthesia to collect lung tissue samples.

Have bronchoalveolar lavage (BAL) performed in the same session using ATS guideline-based protocols.

Be evaluated in a multidisciplinary discussion (MDD) integrating clinical, radiologic, and pathologic findings to establish a final diagnosis.

Interstitial Lung Diseases (ILDs) are a rare group of diseases characterized by inflammation and fibrosis of the lung interstitium, with many subtypes. The incidence is reported as approximately 75 per 100,000 in the US and Europe, and 25.8 in Turkey. ILDs are classified into known causes, idiopathic interstitial pneumonias (IIPs), granulomatous diseases, and other subgroups.

While surgical lung biopsy remains the gold standard for diagnosis, it carries risk of complications. Therefore, cryobiopsy (c-TBB), a minimally invasive method, is preferred, with diagnostic yield ranging between 50-90%.

Bronchoalveolar lavage (BAL) provides cellular analysis from the alveoli, aiding differential diagnosis in ILD but is limited as a sole diagnostic tool. Combined use of c-TBB and BAL may improve diagnostic accuracy and reduce the need for surgical biopsy.

In this study, the diagnostic contribution of simultaneous BAL in patients undergoing c-TBB with a preliminary ILD diagnosis was investigated.

Inclusion Criteria:

• Male and female patients over the age of 18,
• Patients diagnosed with interstitial lung disease through imaging methods, and patients who underwent cryotransbronchial biopsy and bronchoalveolar lavage

Exclusion Criteria:

• Being under 18 years of age,
• Patients diagnosed with malignancy,
• Patients who underwent non-standardized bronchoalveolar lavage,
• Patients whose data are unavailable