Clinical meaning of transbronchial cryobiopsy

Transbronchial lung cryobiopsy (TBLCB) carried out in patients with diffuse parenchymal lung disease is becoming the first choice when histopathologic information is deemed necessary. Standardization of the procedure is nowadays quite well defined thanks to statement/guidelines published. The physical principle by which it works is the Joule-Thomson effect, a cryogenic gas stored in a high pressure environment, when delivered in a lower pressure environment, causes a significant drop of temperature. In the majority of cases and in the large majority of centers, TBLCB is carried out in intubated patients (with orotracheal tubes or rigid tubes) under general anesthesia. C-arc fluoroscopy is the more popular guiding system used. Specimens attached to the tip of the probe are significantly larger compared to those obtained by regular transbronchial lung biopsy and with no crash artifacts. The diagnostic yield (either considering the pathologic report or the final multidisciplinary diagnosis) is around 80%. The more robust studies documented a good agreement between histopathologic data provided by TBLCB and those obtained by surgical lung biopsy in the same patients at the same time (good diagnostic accuracy). The more frequent complication is pneumothorax (5–30 per of the cases), but the more life-threatening complication is major bleeding. In order to reduce significantly the rate of major bleeding, the preventive use of bronchial blockers is strongly recommended. Acute exacerbation of the underlying disorder (mainly idiopathic pulmonary fibrosis) and death related to the procedure are rarely observed. Training and volume of activity of the Center are good predictors of high diagnostic yield and low rate of complications. The future implies introduction of new machinery in the market, rapid onsite examination of the sample without manipulating it, combination of lung cryobiopsy with more complex guiding systems (cone beam-CT computed tomography, etc.), exploiting of samples utilizing routinely immunohistochemistry, and molecular biology tests (genomic classifiers, etc.).