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Several modifiable factors impacted the safety and diagnostic yield of lung cryobiopsy for patients with suspected interstitial lung diseases.

Patient characteristics and modifiable procedural factors contribute to transbronchial lung cryobiopsy outcomes in adults with interstitial lung disease (ILD), according to a systematic review and meta-analysis published in European Respiratory Review.

“Transbronchial lung cryobiopsy procedural factors can be modified to maximize diagnostic yield and safety,” wrote corresponding author Julia A. Lachowicz, MBBS, FRACP, of the Royal Melbourne Hospital Department of Respiratory Medicine, Melbourne, Australia, and study coauthors. “These factors should be considered for individualized clinical decision-making and guideline development.”

Transbronchial lung cryobiopsy is a recommended alternative to surgical lung biopsy in patients with unclassifiable ILD or ILD diagnosed with low confidence. To better understand factors associated with diagnostic performance and safety, researchers conducted a review and meta-analysis that synthesized 70 studies involving 6,183 adults with unclassifiable ILD who underwent the procedure.

The meta-analysis showed a diagnostic yield of 81% with transbronchial lung cryobiopsy. The yield was better with general anesthesia, an ILD multidisciplinary meeting prior to cryobiopsy, a 2.4-mm cryoprobe, higher mean forced vital capacity, and higher mean diffusing capacity for carbon monoxide.

The rate of pneumothorax was 5%. Higher pneumothorax rates occurred with a 2.4-mm cryoprobe, routine post-procedure imaging, multiple lobe sampling, reduced mean diffusing capacity for carbon monoxide, and general anesthesia.

The study also found a 12% rate of moderate-to-severe bleeding. Bleeding rates increased with a 2.4-mm cryoprobe and bleeding score selection.

“Larger cryoprobe sizes affected all major outcomes, with higher diagnostic yield and increased complication rates of pneumothorax and bleeding identified,” the researchers noted.

The risk-to-benefit ratio with larger cryoprobe sizes may vary with a patient’s clinical status and ability to tolerate pneumothorax and bleeding.

General anesthesia was also linked with better diagnostic yield and increased pneumothorax risk. Although it is not known how general anesthesia, compared with sedation, improves diagnostic yield, the researchers suggested it could stem from better control of cough and patient movement.

“Guidelines for optimal transbronchial lung cryobiopsy practice should be updated to reflect these findings in relation to patient pre-procedure assessment, anesthetic modality, and sampling techniques,” Dr. Lachowicz and colleagues wrote. “More consistent description of cryobiopsy techniques is required in future studies to more accurately characterize patient outcomes.”