Diagnostic Yield and Safety of Cryoprobe Transbronchial Lung Biopsy in Diffuse Parenchymal Lung Diseases: Systematic Review and Meta-Analysis

BACKGROUND: Transbronchial lung biopsy with flexible forceps is the most commonly used technique in diagnosis of diseases diffusely involving the lung parenchyma. Recently, transbronchial lung biopsy using the flexible cryoprobe (cryo-transbronchial lung biopsy) has also been reported. Herein, we perform a systematic review and meta-analysis describing the efficacy and safety of cryo-transbronchial lung biopsy. METHODS: The PubMed and EMBASE databases were searched for studies reporting the outcomes of cryo-transbronchial lung biopsy in subjects with diffuse parenchymal lung involvement. The quality of individual studies was assessed using the QualSyst tool. The pooled diagnostic yield of cryo-transbronchial lung biopsy was calculated using proportion meta-analysis (random effects model). Heterogeneity was evaluated using the 12 test and Cochran Q test. Publication bias was determined using both statistical and graphical methods. RESULTS: Our search yielded 14 studies (1,183 subjects). The pooled diagnostic yield of cryotransbronchial lung biopsy was 76.9% (95% CI 67.2-85.3) if only definitive diagnoses were considered and 85.9% (95% CI 78.2-92.2) if both definitive and probable diagnoses were considered. Four studies (321 subjects) the performance of flexible forceps biopsy and cryo-transbronchial lung biopsy. The diagnostic yield of cryo-transbronchial lung biopsy (86.3, 95% CI 80.2-90.8) was significantly higher than that of flexible forceps biopsy (56.5%, 95% CI 27.5-83.2) with an odds ratio of 6.7 (95% CI 3.6-12.4) and a number needed to treat of 4. Lung tissue was obtained in 98% of all samples with cryo-transbronchial lung biopsy and was free of compression artifacts. The size of samples obtained with cryo-transbronchial lung biopsy was significantly bigger compared with flexible forceps biopsy (20.4 vs 4.3 mm(2), P = .005). The complications of cryo-transbronchial lung biopsy included pneumothorax (6.8%), severe bleeding (0.3 %), and death (0.1%). Clinical and statistical heterogeneity was present, and there was evidence of publication bias. CONCLUSIONS: Cryo-transbronchial lung biopsy is a relatively safe procedure with good diagnostic yield in diseases diffusely involving the lung parenchyma.