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Kos B, Mattison L, Ramirez D, Cindrič H, Sigg DC, Iaizzo PA, Stewart MT, Miklavčič D. Determination of lethal electric field threshold for pulsed field ablation in ex vivo perfused porcine and human hearts. Front Cardiovasc Med 2023; 10:1160231. [PMID: 37424913 PMCID: PMC10326317 DOI: 10.3389/fcvm.2023.1160231] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 05/31/2023] [Indexed: 07/11/2023] Open
Abstract
Introduction Pulsed field ablation is an emerging modality for catheter-based cardiac ablation. The main mechanism of action is irreversible electroporation (IRE), a threshold-based phenomenon in which cells die after exposure to intense pulsed electric fields. Lethal electric field threshold for IRE is a tissue property that determines treatment feasibility and enables the development of new devices and therapeutic applications, but it is greatly dependent on the number of pulses and their duration. Methods In the study, lesions were generated by applying IRE in porcine and human left ventricles using a pair of parallel needle electrodes at different voltages (500-1500 V) and two different pulse waveforms: a proprietary biphasic waveform (Medtronic) and monophasic 48 × 100 μs pulses. The lethal electric field threshold, anisotropy ratio, and conductivity increase by electroporation were determined by numerical modeling, comparing the model outputs with segmented lesion images. Results The median threshold was 535 V/cm in porcine ((N = 51 lesions in n = 6 hearts) and 416 V/cm in the human donor hearts ((N = 21 lesions in n = 3 hearts) for the biphasic waveform. The median threshold value was 368 V/cm in porcine hearts ((N = 35 lesions in n = 9 hearts) cm for 48 × 100 μs pulses. Discussion The values obtained are compared with an extensive literature review of published lethal electric field thresholds in other tissues and were found to be lower than most other tissues, except for skeletal muscle. These findings, albeit preliminary, from a limited number of hearts suggest that treatments in humans with parameters optimized in pigs should result in equal or greater lesions.
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Affiliation(s)
- Bor Kos
- Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Lars Mattison
- Cardiac Ablation Solutions, Medtronic, Inc., Minneapolis, MN, United States
| | - David Ramirez
- Department of Surgery, Visible Heart® Laboratories, University of Minnesota, Minneapolis, MN, United States
| | - Helena Cindrič
- Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Daniel C. Sigg
- Cardiac Ablation Solutions, Medtronic, Inc., Minneapolis, MN, United States
| | - Paul A. Iaizzo
- Department of Surgery, Visible Heart® Laboratories, University of Minnesota, Minneapolis, MN, United States
| | - Mark T. Stewart
- Cardiac Ablation Solutions, Medtronic, Inc., Minneapolis, MN, United States
| | - Damijan Miklavčič
- Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
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Wang M, Zarafshani A, Samant P, Merrill J, Li D, Xiang L. Feasibility of Electroacoustic Tomography: A Simulation Study. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2020; 67:889-897. [PMID: 31765310 DOI: 10.1109/tuffc.2019.2955900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The feasibility of electroacoustic tomography (EAT) was investigated for in situ monitoring the electric field distribution in soft tissue. EAT exploits the phenomenon that the amplitude of acoustic emission generated by an electric field is proportional to the electrical energy deposition in tissue. After detecting these acoustic waves with ultrasound transducers, an image of the electric field distribution can be reconstructed in real-time. In our computer simulations, the electric field distribution in soft tissue was generated by solving general partial differential equations (PDEs) using finite element analysis (FEA). The electric field distributions were converted into initial pressure distributions, and the propagation of the induced acoustic waves was simulated using K-Wave simulation. A circular array of 128 ultrasound transducers was placed around the target to detect the acoustic waves, and a time reversal reconstruction algorithm was used to reconstruct the EAT image. A different number of electrodes set at different distances with different voltage inputs on the electrodes were performed to simulate different electric field distributions during electroporation. It was found that the electrical energy deposition in reconstructed EAT imaging is decreased as the distance of the electrodes increases. We also have investigated the sensitivity of the EAT imaging with different voltage inputs. The minimal voltage we can detect with EAT is 970 V at the pulsewidth of 180 ns. The results of this study demonstrated that EAT is a feasible technique for monitoring the electric field distribution and guiding the electrotherapy in future clinical practice.
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Aycock KN, Davalos RV. Irreversible Electroporation: Background, Theory, and Review of Recent Developments in Clinical Oncology. Bioelectricity 2019; 1:214-234. [PMID: 34471825 PMCID: PMC8370296 DOI: 10.1089/bioe.2019.0029] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Irreversible electroporation (IRE) has established a clinical niche as an alternative to thermal ablation for the eradication of unresectable tumors, particularly those near critical vascular structures. IRE has been used in over 50 independent clinical trials and has shown clinical success when used as a standalone treatment and as a single component within combinatorial treatment paradigms. Recently, many studies evaluating IRE in larger patient cohorts and alongside other novel therapies have been reported. Here, we present the basic principles of reversible electroporation and IRE followed by a review of preclinical and clinical data with a focus on tumors in three organ systems in which IRE has shown great promise: the prostate, pancreas, and liver. Finally, we discuss alternative and future developments, which will likely further advance the use of IRE in the clinic.
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Affiliation(s)
- Kenneth N Aycock
- Department of Biomedical Engineering and Mechanics, Virginia Tech-Wake Forest University, Blacksburg, Virginia
| | - Rafael V Davalos
- Department of Biomedical Engineering and Mechanics, Virginia Tech-Wake Forest University, Blacksburg, Virginia
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Wasson EM, Ivey JW, Verbridge SS, Davalos RV. The Feasibility of Enhancing Susceptibility of Glioblastoma Cells to IRE Using a Calcium Adjuvant. Ann Biomed Eng 2017; 45:2535-2547. [PMID: 28849278 DOI: 10.1007/s10439-017-1905-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 08/16/2017] [Indexed: 12/17/2022]
Abstract
Irreversible electroporation (IRE) is a cellular ablation method used to treat a variety of cancers. IRE works by exposing tissues to pulsed electric fields which cause cell membrane disruption. Cells exposed to lower energies become temporarily permeable while greater energy exposure results in cell death. For IRE to be used safely in the brain, methods are needed to extend the area of ablation without increasing applied voltage, and thus, thermal damage. We present evidence that IRE used with adjuvant calcium (5 mM CaCl2) results in a nearly twofold increase in ablation area in vitro compared to IRE alone. Adjuvant 5 mM CaCl2 induces death in cells reversibly electroporated by IRE, thereby lowering the electric field thresholds required for cell death to nearly half that of IRE alone. The calcium-induced death response of reversibly electroporated cells is confirmed by electrochemotherapy pulses which also induced cell death with calcium but not without. These findings, combined with our numerical modeling, suggest the ability to ablate up to 3.2× larger volumes of tissue in vivo when combining IRE and calcium. The ability to ablate a larger volume with lowered energies would improve the efficacy and safety of IRE therapy.
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Affiliation(s)
- Elisa M Wasson
- Department of Mechanical Engineering, Virginia Tech, Goodwin Hall, 635 Prices Fork Road - MC 0238, Blacksburg, VA, 24061, USA. .,Bioelectromechanical Systems Laboratory, Department of Biomedical Engineering and Mechanics, Virginia Tech - Wake Forest University, School of Biomedical Engineering & Sciences, 325 Stanger St., Blacksburg, VA, 24061, USA.
| | - Jill W Ivey
- Department of Biomedical Engineering and Mechanics, Virginia Tech, 325 Stanger Street, Blacksburg, VA, 24061, USA.,Virginia Tech - Wake Forest University, School of Biomedical Engineering & Sciences, Virginia Tech, 325 Stanger St., Blacksburg, VA, 24061, USA
| | - Scott S Verbridge
- Department of Biomedical Engineering and Mechanics, Virginia Tech, 325 Stanger Street, Blacksburg, VA, 24061, USA.,Virginia Tech - Wake Forest University, School of Biomedical Engineering & Sciences, Virginia Tech, 325 Stanger St., Blacksburg, VA, 24061, USA
| | - Rafael V Davalos
- Department of Mechanical Engineering, Virginia Tech, Goodwin Hall, 635 Prices Fork Road - MC 0238, Blacksburg, VA, 24061, USA.,Department of Biomedical Engineering and Mechanics, Virginia Tech, 325 Stanger Street, Blacksburg, VA, 24061, USA.,Virginia Tech - Wake Forest University, School of Biomedical Engineering & Sciences, Virginia Tech, 325 Stanger St., Blacksburg, VA, 24061, USA.,Bioelectromechanical Systems Laboratory, Department of Biomedical Engineering and Mechanics, Virginia Tech - Wake Forest University, School of Biomedical Engineering & Sciences, 325 Stanger St., Blacksburg, VA, 24061, USA
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Sharabi S, Kos B, Last D, Guez D, Daniels D, Harnof S, Mardor Y, Miklavcic D. A statistical model describing combined irreversible electroporation and electroporation-induced blood-brain barrier disruption. Radiol Oncol 2016; 50:28-38. [PMID: 27069447 PMCID: PMC4825337 DOI: 10.1515/raon-2016-0009] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/03/2016] [Indexed: 12/11/2022] Open
Abstract
Background Electroporation-based therapies such as electrochemotherapy (ECT) and irreversible electroporation (IRE) are emerging as promising tools for treatment of tumors. When applied to the brain, electroporation can also induce transient blood-brain-barrier (BBB) disruption in volumes extending beyond IRE, thus enabling efficient drug penetration. The main objective of this study was to develop a statistical model predicting cell death and BBB disruption induced by electroporation. This model can be used for individual treatment planning. Material and methods Cell death and BBB disruption models were developed based on the Peleg-Fermi model in combination with numerical models of the electric field. The model calculates the electric field thresholds for cell kill and BBB disruption and describes the dependence on the number of treatment pulses. The model was validated using in vivo experimental data consisting of rats brains MRIs post electroporation treatments. Results Linear regression analysis confirmed that the model described the IRE and BBB disruption volumes as a function of treatment pulses number (r2 = 0.79; p < 0.008, r2 = 0.91; p < 0.001). The results presented a strong plateau effect as the pulse number increased. The ratio between complete cell death and no cell death thresholds was relatively narrow (between 0.88-0.91) even for small numbers of pulses and depended weakly on the number of pulses. For BBB disruption, the ratio increased with the number of pulses. BBB disruption radii were on average 67% ± 11% larger than IRE volumes. Conclusions The statistical model can be used to describe the dependence of treatment-effects on the number of pulses independent of the experimental setup.
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Affiliation(s)
| | - Bor Kos
- University of Ljubljana, Faculty of Electrical Engineering, Ljubljana, Slovenia
| | - David Last
- The Advanced Technology Center, Sheba Medical Center, Ramat-Gan, Israel
| | - David Guez
- The Advanced Technology Center, Sheba Medical Center, Ramat-Gan, Israel
| | | | | | | | - Damijan Miklavcic
- University of Ljubljana, Faculty of Electrical Engineering, Ljubljana, Slovenia
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Garcia PA, Rossmeisl JH, Neal RE, Ellis TL, Davalos RV. A parametric study delineating irreversible electroporation from thermal damage based on a minimally invasive intracranial procedure. Biomed Eng Online 2011; 10:34. [PMID: 21529373 PMCID: PMC3108916 DOI: 10.1186/1475-925x-10-34] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 04/30/2011] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Irreversible electroporation (IRE) is a new minimally invasive technique to kill undesirable tissue in a non-thermal manner. In order to maximize the benefits from an IRE procedure, the pulse parameters and electrode configuration must be optimized to achieve complete coverage of the targeted tissue while preventing thermal damage due to excessive Joule heating. METHODS We developed numerical simulations of typical protocols based on a previously published computed tomographic (CT) guided in vivo procedure. These models were adapted to assess the effects of temperature, electroporation, pulse duration, and repetition rate on the volumes of tissue undergoing IRE alone or in superposition with thermal damage. RESULTS Nine different combinations of voltage and pulse frequency were investigated, five of which resulted in IRE alone while four produced IRE in superposition with thermal damage. CONCLUSIONS The parametric study evaluated the influence of pulse frequency and applied voltage on treatment volumes, and refined a proposed method to delineate IRE from thermal damage. We confirm that determining an IRE treatment protocol requires incorporating all the physical effects of electroporation, and that these effects may have significant implications in treatment planning and outcome assessment. The goal of the manuscript is to provide the reader with the numerical methods to assess multiple-pulse electroporation treatment protocols in order to isolate IRE from thermal damage and capitalize on the benefits of a non-thermal mode of tissue ablation.
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Affiliation(s)
- Paulo A Garcia
- Bioelectromechanical Systems Laboratory, School of Biomedical Engineering and Sciences, Virginia Tech - Wake Forest University, Blacksburg, VA, USA
| | - John H Rossmeisl
- Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA USA
| | - Robert E Neal
- Bioelectromechanical Systems Laboratory, School of Biomedical Engineering and Sciences, Virginia Tech - Wake Forest University, Blacksburg, VA, USA
| | - Thomas L Ellis
- Department of Neurosurgery, Wake Forest University School of Medicine, Winston-Salem, NC USA
| | - Rafael V Davalos
- Bioelectromechanical Systems Laboratory, School of Biomedical Engineering and Sciences, Virginia Tech - Wake Forest University, Blacksburg, VA, USA
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Garcia PA, Pancotto T, Rossmeisl JH, Henao-Guerrero N, Gustafson NR, Daniel GB, Robertson JL, Ellis TL, Davalos RV. Non-thermal irreversible electroporation (N-TIRE) and adjuvant fractionated radiotherapeutic multimodal therapy for intracranial malignant glioma in a canine patient. Technol Cancer Res Treat 2011; 10:73-83. [PMID: 21214290 PMCID: PMC4527477 DOI: 10.7785/tcrt.2012.500181] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 08/06/2010] [Accepted: 08/24/2010] [Indexed: 11/22/2022] Open
Abstract
Non-thermal irreversible electroporation (N-TIRE) has shown promise as an ablative therapy for a variety of soft-tissue neoplasms. Here we describe the therapeutic planning aspects and first clinical application of N-TIRE for the treatment of an inoperable, spontaneous malignant intracranial glioma in a canine patient. The N-TIRE ablation was performed safely, effectively reduced the tumor volume and associated intracranial hypertension, and provided sufficient improvement in neurological function of the patient to safely undergo adjunctive fractionated radiotherapy (RT) according to current standards of care. Complete remission was achieved based on serial magnetic resonance imaging examinations of the brain, although progressive radiation encephalopathy resulted in the death of the dog 149 days after N-TIRE therapy. The length of survival of this patient was comparable to dogs with intracranial tumors treated via standard excisional surgery and adjunctive fractionated external beam RT. Our results illustrate the potential benefits of N-TIRE for in vivo ablation of undesirable brain tissue, especially when traditional methods of cytoreductive surgery are not possible or ideal, and highlight the potential radiosensitizing effects of N-TIRE on the brain.
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Affiliation(s)
- P. A. Garcia
- Bioelectromechanical Systems Laboratory, School of Biomedical Engineering and Sciences, Virginia Tech-Wake Forest University Blacksburg, VA 24061
- These authors contributed equally to this work
| | - T. Pancotto
- Departments of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061
- These authors contributed equally to this work
| | - J. H. Rossmeisl
- Departments of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061
| | - N. Henao-Guerrero
- Departments of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061
| | - N. R. Gustafson
- Department of Radiation Oncology The Regional Veterinary Referral Center, 6651 Backlick Road, Springfield, VA 22150
| | - G. B. Daniel
- Departments of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061
| | - J. L. Robertson
- Biomedical Sciences and Pathobiology Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061
| | - T. L. Ellis
- Department of Neurosurgery Wake Forest University School of Medicine, Winston-Salem, NC 27157
| | - R. V. Davalos
- Bioelectromechanical Systems Laboratory, School of Biomedical Engineering and Sciences, Virginia Tech-Wake Forest University Blacksburg, VA 24061
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