Biochemical and Hematologic Changes After Percutaneous Radiofrequency Ablation of Liver Tumors: Experience in 83 Procedures

Purpose: To determine the frequency and severity of various abnormal laboratory tests after percutaneous radiofrequency (RF) ablation of liver tumors and to estimate the correlation between laboratory test values and volumes of tumor and ablated tissue.

Materials And Methods: Biochemical and hematologic laboratory values of 83 computed tomography-guided RF ablations of liver tumors were reviewed retrospectively at baseline, 0-6, 6-12, 12-24 hours, and 1-2 weeks, assessed for significant changes, and correlated with tumor, total ablation, and ablative margin (consisting of ablated nontumoral liver parenchyma and calculated by subtracting tumor volume from ablation volume).

Results: Mean total ablation volume was 26.6 mL (range, 3.14-1020.5 mL). Aspartate aminotransferase (AST) values exceeded normal range after 78 (93.9%) procedures and peaked at 12-24 hours (mean, 321 U/L). Alanine aminotransferase (ALT) values exceeded normal range after 58 (69.9%) procedures and peaked at 12-24 hrs (mean, 220 U/L). Bilirubin levels increased after 34 (41%) procedures (mean maximal increase, 1.1 mg/dL) and peaked at 12-24 hours in 13 (36%). Peak AST (r = 0.3), peak ALT (r = 0.3), and peak bilirubin (r = 0.3) levels correlated only with ablation margin volume. Three patients with severely elevated bilirubin and alkaline phosphatase levels had biliary complications. Platelets decreased below 100,000/μL (n = 5) only when the preprocedural level was < 120,000/μL. Severe myoglobinemia occurred once and was treated successfully with serum alkalinization.

Conclusions: Changes in laboratory values after percutaneous RF ablation of liver tumors are common and usually mild and self-limited. Peak aminotranferase levels and bilirubin values correlate with ablative margin volume and, along with elevated alkaline phosphatase, when severe, may be a harbinger of biliary complications.