Biochemical and Hematologic Alterations Following Percutaneous Cryoablation of Liver Tumors : Experience in 48 Procedures

To retrospectively determine the frequency and severity of various abnormal laboratory test values following percutaneous cryoablation of liver tumors and to estimate the correlation between laboratory test values and tumor and ablation volumes. This HIPAA-compliant study had institutional review board approval. Informed consent was waived. Biochemical and hematologic laboratory values from 48 procedures in 39 patients (18 men and 21 women; age range, 29-86 years) who underwent magnetic resonance (MR) imaging-guided percutaneous cryoablation of 65 liver tumors (62 metastases, three hepatocellular carcinomas) were retrospectively reviewed. Changes in laboratory values at baseline and 0-6 hours and 1-2 weeks after the procedure were analyzed with respect to tumor and ablative margin volumes by using generalized estimating equations. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were correlated with percent maximal decrease in platelet count. Mean ablation zone volume was 67.3 cm(3) +/- 41.2 (standard deviation) (range, 7.3-191.4 cm(3)). AST and ALT values increased after all procedures and peaked at 6 hours (median change in AST value, +835 U/L; median change in ALT value, +614.5 U/L). Platelet count decreased after 47 procedures (mean maximal decrease, 92.3 x 10(9)/L [38%]), reaching a nadir at 12-24 hours after 24 procedures (50%) and returning to normal in 31 (84%) of 37 procedures at 1-2 weeks. One procedure was complicated by disseminated intravascular coagulation that necessitated transfusion and arterial embolization. Myoglobin values increased after 21 (44%) of 48 procedures and peaked at 6 hours (trimmed-mean value, 183.4 mug/L). Ablative margin volumes were predictive of changes at 0-6 hours in AST (P = .02), ALT (P = .003), and myoglobin (P < .001) values. Percent maximal decrease in platelet count correlated with peak change in AST (r = 0.72) (P < .001). Following percutaneous cryoablation of liver tumors, alterations in liver enzymes, myoglobin, and platelet count are common, are usually self-limited, and correlate with ablative margin volume--except for changes in platelet count, which correlate with changes in AST and ALT.