Diagnostic Yield and Safety of Pleural Cryobiopsy during Medical Thoracoscopy to Diagnose Pleural Effusion. A Systematic Review and Meta-Analysis.

OBJECTIVE: Current evidence on the diagnostic yield and safety of pleural cryobiopsy (CB) is based on a series of heterogeneous studies with limited cohorts. A pooled analysis of these studies could improve the evidence and contribute to a better understanding of this new technique. METHODOLOGY: We performed a systematic review and meta-analysis of published studies that included data on the yield and diagnostic safety of pleural CB compared with procedures performed using conventional flexible forceps. The heterogeneity of the analysis was evaluated by determining the I2 index, while study quality was measured with the QUADAS-2 tool. RESULTS: Seven studies involving 356 patients were used for the final evaluation. In 55.6%, the etiology of the pleural effusion was malignant, 61.1% of which were lung cancer. The diagnostic yield of pleural CB was 95% (95% CI 92-97) vs. 91% (95% CI 87-94) with conventional flexible forceps (P =  .019). Mild bleeding was reported in 67% of CB procedures (95% CI 62-72) compared with 85% of conventional flexible forceps procedures (95% CI 79-90) (P <  .001). CB specimens were larger, and fewer artifacts were detected. A pooled analysis of the detection of molecular changes could not be performed. Heterogeneity was moderate to high, although the quality of the studies was acceptable. CONCLUSIONS: Pleural CB is a safe technique with a high yield for etiological diagnosis of pleural effusion, and larger specimens with fewer artifacts are obtained. Molecular determinations should be investigated in more depth.