Vessel Patency Post Irreversible Electroporation

The purpose of the study was to evaluate the effect of Irreversible Electroporation (IRE) on vessel patency in close proximity to the ablation zone. Between January 2010 and November 2013, 101 patients underwent percutaneous IRE procedures using the NanoKnife for primary and metastatic tumors in different organs. Age ranged from 24 to 83 years. A total of 129 lesions were treated. [liver (100), pancreas (18), kidney (3), pelvis (1), aorto-caval lymph nodes (2), adrenal (2), lung (1), retroperitoneal (1), surgical bed of a prior Whipple procedure (1)]. Post treatment contrast-enhanced CT and MRI scans were reviewed to evaluate caliber, patency, and flow defects of vessels in close proximity to the ablation zone (defined as vessels within 0-1 cm from the treatment zone). A total of 158 vessels were examined for patency on follow-up. The mean distance of the vessel from the treatment zone was 2.3 +/- A 2.5 mm. Ten vessels within the treatment zone were encased by tumor. Mean tumor size was 2.7 + 1.5 cm. Overall mean follow-up was 10.3 months. Abnormal vascular changes were noted in 7 of 158 (4.4 %) vessels. No significant association was found between distances from the treatment zone and presence of narrowing/thrombosis at the follow-up imaging. (Mann-Whitney U, p = 0.772; logistic regression: p = 0.593; odds ratio: 0.908; CI 0.637-1.294). This study demonstrates safety of IRE for the treatment of tumors near the large blood vessels and tumors already encasing the vessels. Further studies to substantiate these findings are essential to validate this crucial advantage of IRE.