Radiofrequency ablation of normal lungs after pulmonary artery embolization with use of degradable starch microspheres: Results in a porcine model

PURPOSE: The present study was performed to evaluate the effect of pulmonary artery embolization on radiofrequency (RF) ablation of normal porcine lungs. MATERIALS AND METHODS: RF ablation zones (n = 34) were created in the normal lungs of five domestic pigs (five zones in each of the first two pigs and eight zones in each of the remaining three pigs) with an expandable multitined electrode with use of bilateral thoracotomy. RF ablation was performed without pulmonary artery embolization (group 1, n = 8), immediately after embolization (group 2, n = 11),15 minutes after embolization (group 3, n = 7), and 30 minutes after embolization (group 4, n = 8) with degradable starch microspheres. Among them, 12 ablation zones were excluded from this study because they were considerably limited by the presence of the pleura or large bronchi. The remaining 22 zones were included (n = 7, n = 5, n = 4, and n = 6 in groups 1, 2, 3, and 4, respectively). Coagulation necrosis volumes in the ablation zones were measured and compared among the groups. RESULTS: Coagulation necrosis volumes were 0.9 +/- 0.5 cm(3), 2.1 +/- 0.4 cm(3), 2.1 +/- 1.0 cm(3), and 1.9 +/- 0.6 cm(3) in groups 1, 2, 3, and 4, respectively. Groups 2-4 showed significantly larger coagulation volumes than group 1 (P = .012, P = .023, and P = .010 in groups 2, 3, and 4, respectively). CONCLUSION: Pulmonary artery embolization contributed to larger volumes of coagulation necrosis after RF ablation of normal lungs.