Percutaneous Cryoablation in the Liver: A Meta-Analysis and Review of Safety with a Focus on Incidence of Cryoshock and Major Complications.

Purpose
The aim of the present meta-analysis was to systematically determine the overall complication rate and incidence of cryoshock in patients undergoing cryoablation of the liver.Methods
A systematic review and meta-analysis adhering to the PRISMA guidelines and focusing on studies of cryotherapy for liver malignancies published after 2000 were conducted. PubMed, Web of Science, Embase, and Scopus were systematically searched for articles reporting incidences of adverse events associated with percutaneous cryoablation in patients with liver malignancies. Data extraction and screening were independently conducted by two reviewers, who resolved discrepancies through consensus. Statistical analysis was performed to assess heterogeneity and pooled complication rates and included a moderator analysis to explore factors influencing the occurrence of complications.Results
The initial search yielded 4,145 articles, of which 26 met our inclusion criteria. From these 26 articles, pooled data on 4,029 patients were extracted. Variance between studies reporting cryoshock was low (I2 = 13.15%), while variance among studies reporting major complications was high (I2 = 82.52%). The pooled weighted proportion of major complications was 4.71% while that of cryoshock was as low as 0.265%. Moderator analysis identified publication year as the only moderator for major complications and no moderator for the occurrence of cryoshock.Conclusion
Analysis of currently available evidence indicates that cryoablation has a relative safe profile with a pooled incidence of major complications below 5%. Cryoshock occurred in less than 0.3% of procedures and was not reported for liver lesions smaller than 3 cm.