title: Diagnostic Yield and Safety of Cryoprobe Transbronchial Lung Biopsy in Diffuse Parenchymal Lung Diseases: Systematic Review and Meta-Analysis.
abstract: 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 I(2) 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 cryo-transbronchial 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.
authors.affiliation: Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Sahajal
authors.initials: S
authors.lastname: Dhooria
authors.affiliation: Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Inderpaul Singh
authors.initials: IS
authors.lastname: Sehgal
authors.affiliation: Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Ashutosh N
authors.initials: AN
authors.lastname: Aggarwal
authors.affiliation: Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Digambar
authors.initials: D
authors.lastname: Behera
authors.affiliation: Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India. agarwal.ritesh@outlook.in.
authors.forename: Ritesh
authors.initials: R
authors.lastname: Agarwal
mesh_terms: D001706:Biopsy / Q000009:adverse effects / Q000379:methods*; D001999:Bronchoscopy / Q000009:adverse effects / Q000379:methods*; D017679:Cryotherapy / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D008168:Lung / Q000473:pathology*; D017563:Lung Diseases, Interstitial / Q000175:diagnosis*
keywords: bronchoscopy; cryotherapy; idiopathic interstitial pneumonia; idiopathic pulmonary fibrosis; interstitial lung disease; sarcoidosis