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Feasibility and acute safety following catheter directed IRE for endoluminal ablation of the porcine esophagus
JVIR
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Scientific Session
Sunday
Scientific Session 6 Tissue Ablation I Sunday, March 23 2014 3:30 PM – 5:00 PM Room: 16A 3:30 PM
Abstract No. 55
Feasibility and acute safety following catheter directed IRE for endoluminal ablation of the porcine esophagus G. Srimathveeravalli1, T. Wimmer2, S. Monette1, J.C. Durack1, M. Maybody1, H. Gerdes3, S.B. Solomon1;
S31
1
Radiology, Memorial Sloan Kettering Cancer Center, New York, NY; 2Radiology, Medical University of Graz, Graz, Austria; 3GI Service, Memorial Sloan Kettering Cancer Center, New York, NY Purpose: Esophageal ablation with thermal modalities such as radiofrequency ablation (RFA) can be performed for premalignant conditions (Barrett’s esophagus). However, the risk of heat-induced stricture formation and perforation limit use of RFA for the focal ablation of deeper esophageal lesions or large tumors. Irreversible electroporation is a new ablation technique with minimal thermal effects. We evaluate the feasibility and safety of using a novel “wet electrode technique” for nonthermal transmural ablation of the healthy porcine esophagus. Materials and Methods: A catheter directed wet electrode device for esophageal IRE ablation was evaluated in 7 pigs. Treatment settings were derived from numerical simulations to achieve circumferential transmural ablations while avoiding thermal damage. A monopolar electrode was positioned and anchored within the esophagus using an inflatable balloon. The esophagus was filled with a mixture of omnipaque 300 contrast and normal saline to separate the electrode from the esophageal wall and provide an electrical path to surrounding mucosa. A ground-return pad was attached to the gluteal skin. 90 electrocardiogram gated direct current pulses (3000 V, 100 ms) were applied. Computed tomography and fluoroscopy were performed after treatment to assess esophageal integrity. Histological analysis of the ablation zone was performed 24 hours after treatment. Results: Treatment was successfully completed in all animals. Transient ventricular tachycardia was observed in three animals and successfully managed by intravenous administration of lidocaine. Post treatment imaging excluded acute esophageal perforations. In each animal, ablation zones could be identified on gross pathology and circumferential full thickness ablation (3.52⫾0.89mm depth) of the esophageal wall from the mucosa to the adventitia with conservation of the extra-cellular architecture was apparent histologically. No acute histologic changes were identified in nerves adjacent to the treated site. Conclusion: Catheter directed “wet electrode” IRE is feasible for performing non-thermal transmural ablations in the esophagus without acute perforation of the esophageal wall.
3:39 PM
Abstract No. 56
Ice ball size during renal tumor cryoablation: useful predictor of successful ablation? B.H. Ge1, S.W. Stavropoulos1, M.C. Soulen1, T.W. Clark1, T. Guzzo2, B. Malkowicz2, A. Wein2; 1Radiology, Univ of Pennsylvania, Philadelphia, PA; 2Urology, Univ of Pennsylvania, Philadelphia, PA Purpose: Animal models have established a minimal ice ball margin of 0.3 cm for successful percutaneous cryoablation of small renal masses (SRM). This purpose of this study was to examine the CT characteristics of the intraprocedural ice ball during renal mass cryoablation and correlate this to postcryoablation outcomes. Materials and Methods: This was a retrospective review of 63 consecutive patients undergoing percutaneous CT guided
SUNDAY: Scientific Sessions
Purpose: We investigated whether the presence of an oncogene mutation correlated with clinical outcomes among colorectal cancer patients undergoing locoregional therapy for liver metastases. Materials and Methods: In this HIPAA compliant, IRBapproved study, a hospital registry of patients diagnosed with colorectal cancer between 2009 and 2012 with oncogene mutation analysis (SNaPshot) was obtained. Chart review identified those who had received percutaneous radiofrequency ablation and/or transcatheter chemo- or radio-embolization (IR therapy), in addition to routine systemic therapy. Patient demographics, treatment history, SNaPshot data, lab values, and outcomes were recorded. Where available, pre- and postprocedure PET and CT imaging was used to assess the response of target and non-target liver metastases (Fisher’s exact test). Uni- and multi-variate logistic regression (MVR) was performed for the outcome of death, modified by age, gender, and presence of oncogene mutation. Kaplan-Meier (KM) analysis for survival was performed. Alpha level was set at 0.05. Results: Of the 511 patients, 26 had percutaneous intervention for liver metastases. 14 patients were male. Median age was 56 years (range: 32-83). 12 patients had wild-type tumors. 14 patients demonstrated oncogene mutations (7 KRAS, 6 p53). 18 and 21 IR procedures were performed on the wildtype and mutant oncogene groups, respectively. Follow-up PET showed similar rates of stable or improved status of treated lesions among wildtype tumors (6 of 8, 75%) and mutant tumors (9 of 13, 69%). 10 of 12 patients with wild-type tumors died (83%, median survival 49 months); 10 of 14 patients with mutant tumors died (71%, 34 months). In MVR, the presence of an oncogene mutation did not affect overall survival. In adjusted KM analysis, survival favored wild-type tumors in the first 50 months. Conclusion: In patients with colorectal cancer metastatic to the liver treated with IR therapy, survival favored those with wild-type tumors in the first 50 months, compared to those with mutant oncogene profiles. The role of oncogene mutations in tumorgenesis and response to IR therapies warrants further evaluation to improve the selection of patients for IR therapies.
’
’
Scientific Session
Sunday
Scientific Session 6 Tissue Ablation I Sunday, March 23 2014 3:30 PM – 5:00 PM Room: 16A 3:30 PM
Abstract No. 55
Feasibility and acute safety following catheter directed IRE for endoluminal ablation of the porcine esophagus G. Srimathveeravalli1, T. Wimmer2, S. Monette1, J.C. Durack1, M. Maybody1, H. Gerdes3, S.B. Solomon1;
S31
1
Radiology, Memorial Sloan Kettering Cancer Center, New York, NY; 2Radiology, Medical University of Graz, Graz, Austria; 3GI Service, Memorial Sloan Kettering Cancer Center, New York, NY Purpose: Esophageal ablation with thermal modalities such as radiofrequency ablation (RFA) can be performed for premalignant conditions (Barrett’s esophagus). However, the risk of heat-induced stricture formation and perforation limit use of RFA for the focal ablation of deeper esophageal lesions or large tumors. Irreversible electroporation is a new ablation technique with minimal thermal effects. We evaluate the feasibility and safety of using a novel “wet electrode technique” for nonthermal transmural ablation of the healthy porcine esophagus. Materials and Methods: A catheter directed wet electrode device for esophageal IRE ablation was evaluated in 7 pigs. Treatment settings were derived from numerical simulations to achieve circumferential transmural ablations while avoiding thermal damage. A monopolar electrode was positioned and anchored within the esophagus using an inflatable balloon. The esophagus was filled with a mixture of omnipaque 300 contrast and normal saline to separate the electrode from the esophageal wall and provide an electrical path to surrounding mucosa. A ground-return pad was attached to the gluteal skin. 90 electrocardiogram gated direct current pulses (3000 V, 100 ms) were applied. Computed tomography and fluoroscopy were performed after treatment to assess esophageal integrity. Histological analysis of the ablation zone was performed 24 hours after treatment. Results: Treatment was successfully completed in all animals. Transient ventricular tachycardia was observed in three animals and successfully managed by intravenous administration of lidocaine. Post treatment imaging excluded acute esophageal perforations. In each animal, ablation zones could be identified on gross pathology and circumferential full thickness ablation (3.52⫾0.89mm depth) of the esophageal wall from the mucosa to the adventitia with conservation of the extra-cellular architecture was apparent histologically. No acute histologic changes were identified in nerves adjacent to the treated site. Conclusion: Catheter directed “wet electrode” IRE is feasible for performing non-thermal transmural ablations in the esophagus without acute perforation of the esophageal wall.
3:39 PM
Abstract No. 56
Ice ball size during renal tumor cryoablation: useful predictor of successful ablation? B.H. Ge1, S.W. Stavropoulos1, M.C. Soulen1, T.W. Clark1, T. Guzzo2, B. Malkowicz2, A. Wein2; 1Radiology, Univ of Pennsylvania, Philadelphia, PA; 2Urology, Univ of Pennsylvania, Philadelphia, PA Purpose: Animal models have established a minimal ice ball margin of 0.3 cm for successful percutaneous cryoablation of small renal masses (SRM). This purpose of this study was to examine the CT characteristics of the intraprocedural ice ball during renal mass cryoablation and correlate this to postcryoablation outcomes. Materials and Methods: This was a retrospective review of 63 consecutive patients undergoing percutaneous CT guided
SUNDAY: Scientific Sessions
Purpose: We investigated whether the presence of an oncogene mutation correlated with clinical outcomes among colorectal cancer patients undergoing locoregional therapy for liver metastases. Materials and Methods: In this HIPAA compliant, IRBapproved study, a hospital registry of patients diagnosed with colorectal cancer between 2009 and 2012 with oncogene mutation analysis (SNaPshot) was obtained. Chart review identified those who had received percutaneous radiofrequency ablation and/or transcatheter chemo- or radio-embolization (IR therapy), in addition to routine systemic therapy. Patient demographics, treatment history, SNaPshot data, lab values, and outcomes were recorded. Where available, pre- and postprocedure PET and CT imaging was used to assess the response of target and non-target liver metastases (Fisher’s exact test). Uni- and multi-variate logistic regression (MVR) was performed for the outcome of death, modified by age, gender, and presence of oncogene mutation. Kaplan-Meier (KM) analysis for survival was performed. Alpha level was set at 0.05. Results: Of the 511 patients, 26 had percutaneous intervention for liver metastases. 14 patients were male. Median age was 56 years (range: 32-83). 12 patients had wild-type tumors. 14 patients demonstrated oncogene mutations (7 KRAS, 6 p53). 18 and 21 IR procedures were performed on the wildtype and mutant oncogene groups, respectively. Follow-up PET showed similar rates of stable or improved status of treated lesions among wildtype tumors (6 of 8, 75%) and mutant tumors (9 of 13, 69%). 10 of 12 patients with wild-type tumors died (83%, median survival 49 months); 10 of 14 patients with mutant tumors died (71%, 34 months). In MVR, the presence of an oncogene mutation did not affect overall survival. In adjusted KM analysis, survival favored wild-type tumors in the first 50 months. Conclusion: In patients with colorectal cancer metastatic to the liver treated with IR therapy, survival favored those with wild-type tumors in the first 50 months, compared to those with mutant oncogene profiles. The role of oncogene mutations in tumorgenesis and response to IR therapies warrants further evaluation to improve the selection of patients for IR therapies.
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