Rationale: The diagnostic usefulness and safety of transbronchial lung cryobiopsy for the evaluation of interstitial lung disease remain unclear.
Objectives: This systematic review and metaanalysis aims to establish the diagnostic accuracy and yield of transbronchial cryobiopsy for interstitial lung diseases.
Methods: We searched MedLine, EMBASE, Cochrane Central Register of Controlled Trials, and conference proceedings to identify studies assessing the diagnostic accuracy (compared with surgical biopsy) or yield of transbronchial lung cryobiopsy for interstitial lung disease (from database inception to January 2016). The diagnostic accuracy and yield were quantified and stratified by the method of diagnosis determination (histologic interpretation in isolation vs. incorporation within a multidisciplinary discussion). The frequency of procedure-related complications was also assessed from these reports. For full-text studies, random-effects models were used to calculate pooled estimates of diagnostic accuracy, yield, and complication frequency.
Measurements and main results: Of 900 citations, 11 studies were selected for inclusion in this systematic review (7 full text, 4 abstracts). The selected studies reported on a total of 731 patients. No studies reported the diagnostic accuracy of transbronchial cryobiopsy. Diagnostic yield ranged from 74 to 98% when transbronchial cryobiopsy findings were interpreted in isolation, with a pooled estimate of 83% (95% confidence interval [CI], 73-94). Diagnostic yield ranged from 51 to 98% when transbronchial cryobiopsy was reviewed within a multidisciplinary discussion, with a pooled estimate of 79% (95% CI, 65-93). Pooled estimates for pneumothorax and moderate/severe bleeding were 12% (95% CI, 3-21) and 39% (95% CI, 3-76), respectively.
Conclusions: The diagnostic accuracy of transbronchial lung cryobiopsy cannot be determined given the absence of studies directly comparing cryobiopsy diagnoses with diagnoses derived from surgical lung biopsies interpreted within multidisciplinary discussions. The histopathological and multidisciplinary discussion-based diagnostic yield of transbronchial cryobiopsy appears high, but with variable frequencies of complications dominated by pneumothorax and moderate-to-severe hemorrhage.
Keywords: diagnosis; diffuse parenchymal lung diseases; pulmonary fibrosis.