Irreversible Electroporation (IRE) Combined With Chemotherapy Increases Survival in Locally Advanced Pancreatic Cancer (LAPC)

Thermal side effects during pulsed field ablation: an analysis using computer modelling

AIMS

Pulsed field ablation (PFA) is described as non-thermal, but data from oncology and cardiology show thermal effects occur. The specific waveform parameters influencing thermal energy development during PFA are unclear. The aim of this study is to numerically evaluate the thermal effects of PFA on myocardial and oesophageal tissue at various peak voltage conditions.

METHODS AND RESULTS

A three-dimensional computer model of the left atrium quantified thermal effects from PFA at peak voltages of 1, 1.5, and 2 kV. Energy was applied using a bipolar configuration with far-field and symmetry boundaries set as electrically insulating. A monophasic waveform with a 100 μs pulse width and a 1 s gap between pulses was applied for a total of 50 pulses, mimicking clinical conditions. Minimal temperature rise in the oesophagus was observed with 1 kV pulses (214.5 J). At 1.5 and 2 kV (570.3 and 1.23 kJ), temperatures reached 46.3°C and >62°C, respectively, after a single pulse train. These findings suggest that repeated applications could lead to even higher temperatures, especially if good tissue contact is obtained. These results align with data from other medical fields using pulsed field treatments.

CONCLUSION

Thermal effects from PFA depend on the total energy deposited, with peak voltage being a significant factor. Current commercially available PFA systems have the potential to induce collateral thermal injury with repeated applications of pulsed field energy. This highlights the need for careful monitoring and adjustment of PFA parameters in clinical settings.

Esophageal cooling vs luminal esophageal temperature monitoring in high-power short-duration ablation of paroxysmal atrial fibrillation

BACKGROUND

Treatment of PAF with PVI is the gold standard approach. Recently, esophageal cooling has been shown to significantly reduce the risk of esophageal injury during thermal ablation. This study investigated outcomes of HPSD before and after instituting esophageal cooling.

METHODS

In this natural experiment, we enrolled 346 consecutive patients with PAF undergoing initial ablation using HPSD, 143 patients immediately prior to and 203 patients immediately after switching from luminal esophageal monitoring (LET arm) to esophageal cooling with ensoETM (ensoETM arm). The primary endpoint was time-to-atrial arrhythmia recurrence.

RESULTS

The procedure times were significantly faster with ensoETM (82.9 ± 27 vs 112 ± 49 min, p < 0.0001). At a median follow-up of 10.3 ± 3.4 months, the atrial arrhythmia recurrence rate did not significantly differ between LET and ensoETM arms (25.2% vs 30.0%, p = 0.3202). Kaplan-Meier analysis showed no significant difference in the overall atrial arrhythmia recurrence (log-rank, p = 0.3780). Statistical analysis of all notable comorbidities revealed no significant association with procedural outcomes.

CONCLUSION

In patients with PAF undergoing an initial ablation procedure with HPSD, esophageal cooling led to significantly faster procedures, with no decrease in efficacy.

Proactive esophageal cooling during radiofrequency cardiac ablation: data update including applications in very high-power short duration ablation

INTRODUCTION

Proactive esophageal cooling reduces injury during radiofrequency (RF) ablation of the left atrium (LA) for the treatment of atrial fibrillation (AF). New catheters are capable of higher wattage settings up to 90 W (very high-power short duration, vHPSD) for 4 s. Varying power and duration, however, does not eliminate the risk of thermal injury. Furthermore, alternative energy sources such as pulsed field ablation (PFA) also exhibit thermal effects, with clinical data showing esophageal temperatures up to 40.3°C. The ensoETM esophageal cooling device (Attune Medical, now a part of Haemonetics, Boston, MA, U.S.A.) is commercially available and FDA-cleared to reduce thermal injury to the esophagus during RF ablation for AF and is recommended in the 2024 expert consensus statement on catheter and surgical ablation of AF.

AREAS COVERED

This review summarizes growing evidence of esophageal cooling during high power RF ablation for AF treatment, including data relating to procedural efficacy, safety, and efficiency, and techniques to enhance operator success while providing directions for further research.

EXPERT OPINION

Proactive esophageal cooling reduces injury to the esophagus during high power RF ablation, and utilizing this approach may result in increased success in first-pass isolation, procedural efficiency, and long-term efficacy.

Electroporation in Cancer Therapy: A Simplified Model Derived from the Hodgkin-Huxley Model

Cancer remains a global health challenge, necessitating effective treatments with fewer side effects. Traditional methods such as chemotherapy and surgery often have complications. Pulsed electric fields and electroporation have emerged as promising approaches to mitigate these challenges. This study presents a comprehensive overview of electroporation as an innovative tool in cancer therapy, encompassing critical elements such as pulse generators and delivery devices. Furthermore, it introduces a simplified reversible electroporation model grounded in the Hodgkin-Huxley model. This model ensures resting potential stability by regulating ionic currents. When membrane charges reach the electroporation threshold, the model swiftly increases the fraction of open pores, resulting in a rapid rise in electroporation current. Conversely, as the transmembrane potential drops below the threshold, the model gradually reduces the fraction of open pores, leading to a gradual decline in electroporation current, indicating pore resealing. This model contributes to easier modeling and implementation of reversible electroporation dynamics, providing a valuable tool for further exploration of electroporation for cancer therapy.

Mechanisms of action behind the protective effects of proactive esophageal cooling during radiofrequency catheter ablation in the left atrium

Proactive esophageal cooling for the purpose of reducing the likelihood of ablation-related esophageal injury resulting from radiofrequency (RF) cardiac ablation procedures is increasingly being used and has been Food and Drug Administration cleared as a protective strategy during left atrial RF ablation for the treatment of atrial fibrillation. In this review, we examine the evidence supporting the use of proactive esophageal cooling and the potential mechanisms of action that reduce the likelihood of atrioesophageal fistula (AEF) formation. Although the pathophysiology behind AEF formation after thermal injury from RF ablation is not well studied, a robust literature on fistula formation in other conditions (eg, Crohn disease, cancer, and trauma) exists and the relationship to AEF formation is investigated in this review. Likewise, we examine the abundant data in the surgical literature on burn and thermal injury progression as well as the acute and chronic mitigating effects of cooling. We discuss the relationship of these data and maladaptive healing mechanisms to the well-recognized postablation pathophysiological effects after RF ablation. Finally, we review additional important considerations such as patient selection, clinical workflow, and implementation strategies for proactive esophageal cooling.

Atrioesophageal Fistula Rates Before and After Adoption of Active Esophageal Cooling During Atrial Fibrillation Ablation

BACKGROUND

Active esophageal cooling reduces the incidence of endoscopically identified severe esophageal lesions during radiofrequency (RF) catheter ablation of the left atrium for the treatment of atrial fibrillation. A formal analysis of the atrioesophageal fistula (AEF) rate with active esophageal cooling has not previously been performed.

OBJECTIVES

The authors aimed to compare AEF rates before and after the adoption of active esophageal cooling.

METHODS

This institutional review board (IRB)-approved study was a prospective analysis of retrospective data, designed before collecting and analyzing the real-world data. The number of AEFs occurring in equivalent time frames before and after adoption of cooling using a dedicated esophageal cooling device (ensoETM, Attune Medical) were quantified across 25 prespecified hospital systems. AEF rates were then compared using generalized estimating equations robust to cluster correlation.

RESULTS

A total of 14,224 patients received active esophageal cooling during RF ablation across the 25 hospital systems, which included a total of 30 separate hospitals. In the time frames before adoption of active cooling, a total of 10,962 patients received primarily luminal esophageal temperature (LET) monitoring during their RF ablations. In the preadoption cohort, a total of 16 AEFs occurred, for an AEF rate of 0.146%, in line with other published estimates for procedures using LET monitoring. In the postadoption cohort, no AEFs were found in the prespecified sites, yielding an AEF rate of 0% (P < 0.0001).

CONCLUSIONS

Adoption of active esophageal cooling during RF ablation of the left atrium for the treatment of atrial fibrillation was associated with a significant reduction in AEF rate.

State-of-the-Art and Upcoming Innovations in Pancreatic Cancer Care: A Step Forward to Precision Medicine

Pancreatic cancer remains a social and medical burden despite the tremendous advances that medicine has made in the last two decades. The incidence of pancreatic cancer is increasing, and it continues to be associated with high mortality and morbidity rates. The difficulty of early diagnosis (the lack of specific symptoms and biomarkers at early stages), the aggressiveness of the disease, and its resistance to systemic therapies are the main factors for the poor prognosis of pancreatic cancer. The only curative treatment for pancreatic cancer is surgery, but the vast majority of patients with pancreatic cancer have advanced disease at the time of diagnosis. Pancreatic surgery is among the most challenging surgical procedures, but recent improvements in surgical techniques, careful patient selection, and the availability of minimally invasive techniques (e.g., robotic surgery) have dramatically reduced the morbidity and mortality associated with pancreatic surgery. Patients who are not candidates for surgery may benefit from locoregional and systemic therapy. In some cases (e.g., patients for whom marginal resection is feasible), systemic therapy may be considered a bridge to surgery to allow downstaging of the cancer; in other cases (e.g., metastatic disease), systemic therapy is considered the standard approach with the goal of prolonging patient survival. The complexity of patients with pancreatic cancer requires a personalized and multidisciplinary approach to choose the best treatment for each clinical situation. The aim of this article is to provide a literature review of the available treatments for the different stages of pancreatic cancer.

Pancreatic Cancer: Challenges and Opportunities in Locoregional Therapies

Simple Summary

Pancreatic cancer is a serious ongoing global health burden, with an overall 5-year survival rate of less than 5%. One major hurdle in the treatment of this disease is the predominantly elderly patient population, leading to their ineligibility for curative surgery and a low rate of successful outcomes. Systemic administration introduces chemo-agents throughout the body via the blood, attacking not only tumours but also healthy organs. When localised interventions are employed, chemo-agents are retained specifically at tumour site, minimizing unwanted toxicity. As a result, there is a growing interest in finding novel localised interventions as alternatives to systemic therapy. Here, we present a detailed review of current locoregional therapies used in pancreatic cancer therapy. This work aims to present a thorough guide for researchers and clinicians intended to employ established and novel localised interventions in the treatment of pancreatic cancer. Furthermore, we present our insights and opinions on the potential ideals to improve these tools.

Abstract

Pancreatic cancer (PC) remains the seventh leading cause of cancer-related deaths worldwide and the third in the United States, making it one of the most lethal solid malignancies. Unfortunately, the symptoms of this disease are not very apparent despite an increasing incidence rate. Therefore, at the time of diagnosis, 45% of patients have already developed metastatic tumours. Due to the aggressive nature of the pancreatic tumours, local interventions are required in addition to first-line treatments. Locoregional interventions affect a specific area of the pancreas to minimize local tumour recurrence and reduce the side effects on surrounding healthy tissues. However, compared to the number of new studies on systemic therapy, very little research has been conducted on localised interventions for PC. To address this unbalanced focus and to shed light on the tremendous potentials of locoregional therapies, this work will provide a detailed discussion of various localised treatment strategies. Most importantly, to the best of our knowledge, the aspect of localised drug delivery systems used in PC was unprecedentedly discussed in this work. This review is meant for researchers and clinicians considering utilizing local therapy for the effective treatment of PC, providing a thorough guide on recent advancements in research and clinical trials toward locoregional interventions, together with the authors’ insight into their potential improvements.

The Synergistic Role of Irreversible Electroporation and Chemotherapy for Locally Advanced Pancreatic Cancer

Irreversible electroporation (IRE) is a local ablative technique used in conjunction with chemotherapy to treat locally advanced pancreatic cancer (LAPC). The combination of IRE and chemotherapy has showed increased overall survival when compared to chemotherapy alone, pointing towards a possible facilitating effect of IRE on chemotherapeutic drug action and delivery. This review aims to present current chemotherapeutic regimens for LAPC and their co-implementation with IRE, with an emphasis on possible molecular augmentative mechanisms of drug delivery and action. Moreover, the potentiating mechanism of IRE on immunotherapy, M1 oncolytic virus and dendritic cell (DC)-based treatments is briefly explored. Investigating the synergistic effect of IRE on currently established treatment regimens as well as newer ones, may present exciting new possibilities for future studies seeking to improve current LAPC treatment algorithms.