Ablation Modality Research Articles

LA strain analysis in patients undergoing atrial fibrillation ablation using cryoballoon or pulsed-field-ablation

Abstract Background Catheter ablation for atrial fibrillation (AF) is increasing as rhythm control therapy. Besides thermal ablation approaches, such as cryoballoon ablation (CBA), a novel non-thermal and tissue-specific ablation modality – pulsed field ablation (PFA) – has been introduced. Left atrial reservoir strain (LArS) has been suggested to predict arrhythmia recurrences after AF ablation. Up to now, data describing LArS in patients undergoing their first AF ablation using PFA or CBA are sparse. Purpose To compare LArS in patients undergoing first catheter ablation for AF using either PFA or CBA. Methods Patients with transthoracic echocardiography prior to their first catheter ablation for AF were included. Patients in AF during transthoracic echocardiography, with poor 2D image quality and those that did not have a transthoracic echocardiography after AF ablation were excluded. Clinical characteristics and echocardiography parameters were analyzed. LArS was measured before and after AF ablation and was correlated with the recurrence of atrial arrhythmias in the follow-up period. Results Of 267 patients undergoing their first AF ablation, 67 patients (69% male, 65 ± 11 years) fulfilled the inclusion criteria and were further analyzed. AF ablation was performed using PFA in 55% and CBA in 45% of patients. Baseline characteristics were similar in both groups. Before ablation LArS was similar for PFA (17.69 ± 6.92%) and CBA patients (19.38 ± 9.42%, P=0.45). After AF ablation, LArS did not change significantly compared to the values before (before ablation: 20.96 ± 15.9 vs. after ablation: 19.87 ± 9.38, P=0.18), irrespective of the ablation mode (PFA before: 17.69 ± 6.92%vs. PFA after: 18.06 ± 8.9%, P=0.53; CBA before: 19.38 ± 9.42% vs. CBA after: 21.08 ± 9.48%, P=0.36). After a median of 190 days [95% confidence interval: 89 - 454 days], 25 patients (37%) experienced an arrhythmia recurrence (PFA: 38%, CBA: 37%). Comparing patients with and without arrhythmia recurrences, LArS before catheter ablation was lower in those experiencing an arrhythmia recurrence (16.02 ± 6.8%) compared to those without arrhythmia recurrence (25.58 ± 20.32%, P=0.02). However, this was independent from the ablation mode (PFA: AF-recurrence: 16.51 ± 4.27 vs. no recurrence: 21.31 ± 15.9, P=0.19; CBA: AF-recurrence: 15.48 ± 9.03 vs. no recurrence: 27.34 ± 22.14, P=0.07). Univariable regression analysis - including sex, age and comorbidities - revealed a trend for baseline LArS being associated with arrhythmia recurrence (HR 0.92, 95% CI: 0.86 – 1.01; P=0.065). Conclusions This hypothesis generating study indicates that LArS is not affected by AF ablation irrespective of the ablation mode. Patients with lower LArS before ablation had more arrhythmia recurrences independent of the ablation mode. A larger patient population is needed to assess the association of LArS and arrhythmia recurrences after AF ablation using different ablation modalities.

Safety and effectiveness of pulsed field ablation for pulmonary vein isolation in atrial fibrillation patients: a single centre experience

Abstract Introduction Atrial Fibrillation (AF) is the most frequent arrhythmia in the world with an exponentially increasing prevalence. Pulmonary veins (PV) are the primary triggering sites for AF and pulmonary veins isolation (PVI) is currently the standard therapy alongside pharmacological treatment and should be considered as first-line treatment. Pulsed-fieldablation (PFA) is a novel ablation modality that involves the application of electrical pulses causing cellular death, with preferential tissue specificity. Aim In this study, we evaluated the safety and efficacy of single-shot PFA in AF patients. Methods Single-center registry of consecutive patients undergoing PVI using the pentaspline PFA catheter (all with CARTO3D system v.7 and high-density mapping), between June 2022 and November 2023. Data on demographics, procedural characteristics, and electrocardiographic recurrence (assessed after a 3-month blanking period) were analyzed. Results 152 consecutive patients were included (63 ± 10 years, 57% male), with a mean CHA2DS2-VASc score of 2±1 points, median LVEF of 60% (IQR 59-65%), and a median CT-scan derived left atrial volume index of 56 mL/m2(IQR 44-69 mL/m2). A total of 40% had non-paroxysmal AF and a redo procedure was performed in 17% of patients. The median procedure time was 78 min (IQR 58-111 min) and fluoroscopy time was 11.6 min (IQR 8.2-15.6 min). Additionally, posterior wall isolation (PWI) was performed in 63 patients (41%). There were no esophageal complications, phrenic nerve injuries, cerebrovascular events, or procedure-related deaths. Two patients (1.3%) experienced acute cardiac tamponade, immediately treated with pericardiocentesis. Other complications were primarily vascular, in 5% of cases (4 femoral hematomas, 3 femoral pseudoaneurysms, 1 arteriovenous fistula). Over 293 (IQR 170 - 394) days of follow-up, considering electrocardiographic recurrence, 12% of patients had AF recurrence (5 with paroxysmal AF and 10 with persistent AF). These patients were older (69 ± 7y vs. 62 ± 11y, p=0.016), were more likely to undergo a redo procedure (33 vs. 8%, p=0.004), and had a higher percentage of posterior wall isolation (21 vs. 8%, p=0.038). Conclusions PFA for PVI wall ablation is safe and effective, with 100% intraprocedural technical success, a low rate of complications, and a high percentage of patients free from AF in the short-term.

Long-term patient clinical benefits and healthcare utilization after pulsed field ablation in paroxysmal atrial fibrillation: sub-analyses from the multicenter inspIRE trial

Abstract Background/Introduction The treatment of atrial fibrillation (AF) with pulsed field ablation (PFA) aims to prevent AF recurrence while reducing complications from the ablation modality. Similar to thermal ablation, PFA has proven to be safe and effective for treatment of paroxysmal AF (PAF); however, there is scarce evidence on patient-related clinical benefits, including healthcare utilization, using this new energy modality. Purpose The objective of this study is to assess long-term clinical improvements in patient care, symptoms, and quality-of-life (QOL) after PFA ablation in PAF. Methods InspIRE was a multicentre study evaluating the safety and efficacy of variable loop PFA catheters integrated with a 3D mapping system for treatment of symptomatic PAF. Patients were followed for up to 12 months for the following QOL and healthcare utilization endpoints: Atrial Fibrillation Effect on Quality-of-Life (AFEQT) score, Class I/III AAD utilization, repeat ablation, incidence of direct current cardioversion (DCCV), and cardiovascular (CV) hospitalization. Post-hoc Kaplan-Meier estimates for clinical benefit success at 12 months were provided. Success was defined as composite freedom from occurrence of the following events post-blanking: repeat ablation, CV hospitalization, AAD utilization, and DCCV post-blanking. Predictors of clinical benefit success were explored via multivariate logistic regression analysis. Results A total of 186 enrolled patients (59±10 years; 70.0% male; CHA2DS2-VASC score 1.3±1.2) underwent PVI. Compared to baseline: 1) improvements in the AFEQT composite score were seen at 12 months (P<0.001); 2) Class I/III AAD use was reduced from 81.7% to 20.1% at 6-12 months (P<0.05); and 3) the proportion of subjects with DCCV decreased from 13.7% up to 12 months before the index procedure to 3.3% up to 12 months after the index procedure (P<0.001, Figure 1). Minimal clinically important difference in QoL (≥5 points improvement in AFEQT) was achieved in 85.2% of patients. Patients free from 12-month AF/AT/AFL recurrence (asymptomatic and symptomatic) had significantly greater improvements in AFEQT scores from baseline to 12 months versus those with recurrence (P=0.01). The clinical benefit success rate at 12 months was 87.5% (Figure 2). Patients who failed the clinical benefit endpoint were counted, including those with repeat ablation (7.5%), those on new or higher dose of AAD (6.5%), those hospitalized for CV (4.8%), and those who had DCCV post-blanking (1.6%). Multivariate logistic regression analysis showed that left ventricle ejection fraction <60% (OR: 0.22; 95% CI: 0.08-0.62; P<0.05) and incidence of diabetes (OR: 7.25; 95% CI: 2.00, 26.3; p<0.05) were associated with a higher risk of clinical benefit failure. Conclusions PFA ablation of PAF patients led to a clinical benefit success rate of 87.5%, with clinically meaningful improvement in QOL, as well as a reductions in AAD use, cardioversion, and hospitalization.Figure 1.Improvements in QoL and HealthFigure 2.Kaplan-Meier Analysis of Time

Comparison of pulsed field ablation versus cryoballon and radiofrequency ablation for pulmonary vein isolation in atrial fibrillation patients with heart failure

Abstract Background Pulmonary vein isolation (PVI) is the gold standard for atrial fibrillation (AF) ablation and can be achieved by a variety of technical methodes. While thermal ablation modalities (TA), such as cryoballon (CB) and radiofrequency ablation (RF) have been established as the standard approaches, PFA has been introduced as a nvel non-thermal modality showing comparable safety and procedural efficiency. Despite the high incidence of AF in heart failure (HF) patients, data comparing outcomes of HF patients undergoing PVI by either PFA or thermal ablation (RFA/CB) are limited. Purpose This study’s aim was to compare the efficacy and safety of PFA for AF ablation versus CB/RFA in HF patients. Methods Consecutive HF patients with preserved (HFpEF), mildly reduced (HFmrEF) and reduced (HFrEF) ejection fraction undergoing PVI for AF by either PFA or CB/RFA at our institution were included. The primary end-point was time to death or recurrence of AF. Secondary end-points were periprocedural complications and clinical and echocardiographic parameters. Results We included 140 HF patients who underwent PVI either by PFA (PFA group, 76 patients) or thermal ablation approaches (TA group, 64 patients). Our patients had a mean age of 69 years and were predominantly male (62%). There was no significant difference in the baseline characteristics and in the type of AF between both groups (42% with ParAF, 45% with PersAF) and 13% LSPersAF). The distribution of heart failure types was similar between both groups: HFpEF (PFA: 71%, TA: 75%), HFmrEF (PFA: 21%, TA: 20%) and HFrEF (PFA: 8 %, TA: 5%). After the 365-days follow-up period we observed no significant difference for the primary end-point between both groups (HR: 0.79, 95% CI 0.35-1.78; p=0.575). In total 58% of the PFA patients and 59% of the TA group were still free from AF. While symptom improvement was documented in both groups, patients in the PFA group showed significant improvement of left atrial volume index (p = 0.014), NT-pro BNP levels (p = 0.046), and left ventricular ejection fraction (LVEF) (p = 0.005). Conclusion In this study, PFA and thermal ablation modalities showed comparable results in terms of safety and procedural efficiency in patients with heart failure. Since previous studies have shown that HF patients with AF benefit from PVI using thermal ablation modalities, our results suggest that PFA might also be a promising ablation method in this vulnerable population, inducing left atrial reverse remodeling and thereby contributing to improvement of left ventricular systolic function.

Combined PVI and LAAC is feasible using RFA or PFA in a canine model despite acute tissue edema in PFA versus RFA

Abstract Background Combined procedure with pulmonary vein isolation (PVI) using thermal energy followed by left atrial appendage closure (LAAC) has been used in select patient populations with positive results. Pulsed field ablation (PFA) is a novel non-thermal ablation modality that ablates cardiac tissue by irreversible electroporation. The effect of PFA on cardiac tissue and its interaction with a LAAC device in a single procedure has not been studied. Purpose To evaluate using transesophageal echo (TEE) imaging the acute tissue response following ablation by PFA compared to radiofrequency ablation (RFA) and its interaction with the WATCHMAN FLX Pro LAAC device when used in a combined procedure in a healthy canine model. Methods Nine mongrel canines underwent PVI using either circumferential PFA (FARAPULSE) energy application (n=6) or RFA energy (n=3). TEE imaging was obtained at the time of the procedure before and immediately after ablation energy application. The general appearance and echogenicity of the left lateral ridge was assessed and the os of the left atrial appendage (LAA) was measured in the four standard TEE views (0, 45, 90, and 135 degrees). Decisions about device sizing were made accordingly. PVI was evaluated by entry and exit block in all veins except the right inferior pulmonary vein (RIPV), which was not ablated. Following ablation, the LAAC device was implanted using TEE and fluoroscopic guidance in all animals and the percentage of compression measured. PASS criteria were assessed before the release of each device. All animals received dual antiplatelet therapy post implant. Results PVI was confirmed in all animals (except RIPV which was not targeted for ablation) using PFA and RFA. LAA dimensions (at device landing site) did not change substantially after RF ablation. With PFA, there was evidence of more diffuse edema and decrease in LAA diameter (Table). The LAAC device was implanted successfully after meeting PASS criteria in all animals within 30 minutes post ablation. The device size was decreased following PFA in two (2/6) animals, whereas there was no deviation from baseline measurements in device size for any of the RFA animals. Average LAAC device compression was higher for PFA versus RFA animals (Table). TEE post implant confirmed absence of any peri-device leaks in all animals. Conclusion Concomitant PVI using PFA (FARAPULSE) and LAAC (WATCHMAN FLX Pro) is feasible with 100% success and no residual acute peri-device leak. In the canine model, PFA is associated with more diffuse edema compared to RFA, which might affect device sizing. Long term consequences of this acute edema need to be evaluated in serial imaging and future larger clinical trials.Table

A Tumor-Homing Nanoframework for Synergistic Microwave Tumor Ablation and Provoking Strong Anticancer Immunity Against Metastasis.

Microwave thermotherapy (MT) is a clinical local tumor ablation modality, but its applications are limited by its therapeutic efficacy and safety. Therefore, developing sensitizers to optimize the outcomes of MT is in demand in clinical practice. Herein, we engineered a special nanoframework (i.e., FdMI) based on a fucoidan-decorated zirconium metal-organic framework incorporating manganese ions and liquid physisorption for microwave tumor ablation. The monodisperse nanoframework exhibited both microwave thermal effects and microwave dynamic effects, which could effectively kill cancer cells by efficient intracellular drug delivery. Through fucoidan-mediated targeting of P-selectin in the tumor microenvironment (TME), the FdMI effectively accumulated in tumor regions, leading to significant eradication of orthotropic triple-negative breast cancer (TNBC) and aggressive Hepa1-6 liver tumors by the synergistic effects of microwave thermotherapy/dynamic therapy (MT/MDT). The eradication of primary tumors could activate systemic immune responses, which effectively inhibited distant TNBC tumors and lung metastasis of Hepa1-6 liver tumors, respectively. This work not only engineered nanoparticle sensitizers for tumor-targeted synergistic MT/MDT but also demonstrated that nanocarrier-based microwave tumor ablation could stimulate antitumor immunity to effectively inhibit distant and metastatic tumors, demonstrating the high potential for effectively managing advanced malignant tumors.

A comprehensive numerical procedure for high-intensity focused ultrasound ablation of breast tumour on an anatomically realistic breast phantom.

High-Intensity Focused Ultrasound (HIFU) as a promising and impactful modality for breast tumor ablation, entails the precise focalization of high-intensity ultrasonic waves onto the tumor site, culminating in the generation of extreme heat, thus ablation of malignant tissues. In this paper, a comprehensive three-dimensional (3D) Finite Element Method (FEM)-based numerical procedure is introduced, which provides exceptional capacity for simulating the intricate multiphysics phenomena associated with HIFU. Furthermore, the application of numerical procedures to an anatomically realistic breast phantom (ARBP) has not been explored before. The integrity of the present numerical procedure has been established through rigorous validation, incorporating comparative assessments with previous two-dimensional (2D) simulations and empirical data. For ARBP ablation, the administration of a 0.1 MPa pressure input pulse at a frequency of 1.5 MHz, sustained at the focal point for 10 seconds, manifests an ensuing temperature elevation to 80°C. It is noteworthy that, in contrast, the prior 2D simulation using a 2D phantom geometry reached just 72°C temperature under the identical treatment regimen, underscoring the insufficiency of 2D models, ascribed to their inherent limitations in spatially representing acoustic energy, which compromises their overall effectiveness. To underscore the versatility of this numerical platform, a simulation of a more clinically relevant HIFU therapy procedure has been conducted. This scenario involves the repositioning of the ultrasound focal point to three separate lesions, each spaced at 3 mm intervals, with ultrasound exposure durations of 6 seconds each and a 5-second interval for movement between focal points. This approach resulted in a more uniform high-temperature distribution at different areas of the tumour, leading to the ablation of almost all parts of the tumour, including its verges. In the end, the effects of different abnormal tissue shapes are investigated briefly as well. For solid mass tumors, 67.67% was successfully ablated with one lesion, while rim-enhancing tumors showed only 34.48% ablation and non-mass enhancement tumors exhibited 20.32% ablation, underscoring the need for multiple lesions and tailored treatment plans for more complex cases.

Microwave ablation: a technical and clinical comparison to other thermal ablation modalities to treat benign and malignant thyroid nodules

Microwave ablation: a technical and clinical comparison to other thermal ablation modalities to treat benign and malignant thyroid nodules

The Role of Whole-Gland and Focal Cryotherapy in Recurrent Prostate Cancer.

Prostate cancer is the most common non-cutaneous malignancy in men, with the majority of newly diagnosed patients eligible for active surveillance. Despite definitive treatment, a considerable percentage of men will experience biochemical recurrence and even regional and distant metastatic recurrence after radiation therapy or radical prostatectomy. Salvage prostatectomy, while oncologically effective, poses significant morbidity with poor functional outcomes. Salvage cryotherapy has emerged as a promising alternative for localized recurrence, demonstrating safety and efficacy. This review examines the oncologic and functional outcomes of whole-gland and focal salvage cryotherapy, including disease-free survival, cancer-specific survival, and overall survival. The crucial role of multiparametric prostate MRI and evolving role of next-generation PSMA-targeted PET imaging are also examined. The comparison of outcomes of cryotherapy to other salvage ablation modalities, such as high-intensity focused ultrasound (HIFU), is also explored.

Oncologic Outcomes after Percutaneous Ablation for Colorectal Liver Metastases: An Updated Comprehensive Review.

Colorectal cancer is a major cause of cancer-related mortality, with liver metastases occurring in over a third of patients, and is correlated with poor prognosis. Despite surgical resection being the primary treatment option, only about 20% of patients qualify for surgery. Current guidelines recommend thermal ablation either alone or combined with surgery to treat limited hepatic metastases, provided that all visible disease can be effectively eradicated. Several ablation modalities, including radiofrequency ablation, microwave ablation, cryoablation, irreversible electroporation and histotripsy, are part of the percutaneous ablation armamentarium. Thermal ablation, including radiofrequency, microwave ablation and cryoablation, can offer local tumor control rates comparable to limited resection for selected tumors that can be ablated with margins. This review aims to encapsulate the current clinical evidence regarding the efficacy and oncologic outcomes after percutaneous ablation for the treatment of colorectal liver metastatic disease.

Tissue Oedema Following Pulsed Field Ablation Recognized during a Concomitant Left Atrial Appendage Closure Procedure. A Case Report

Abstract Background In patients with non-valvular atrial fibrillation (AF), at high stroke risk and who are ineligible for long-term oral anticoagulation the left atrial appendage closure (LAAC) could be an alternative to anticoagulation. Pulsed field ablation (PFA) is a new nonthermal method for cardiac ablation modality based on high-voltage electrical energy for irreversible electroporation. We first report a case of a concomitant PFA pulmonary vein isolation and LAAC. Case Summary A 74-year-old female patient was referred to our department for pulmonary vein isolation (PVI) for persistent AF (CHA2DS2-VASc Score 5). A concomitant percutaneous LAAC was proposed because of a history of previous cerebellar transient ischemic attack despite continuous oral anticoagulation therapy. PVI was achieved with a pentaspline PFA catheter, LAAC performed with a WATCHMAN FLXTM device (Boston Scientific, Plymouth, MN, USA). After PVI, a swelling of the left atrial ridge was observed, yet a 27 mm LAAC device was successfully implanted. The follow-up transesophageal echo (TEE) after 6 weeks showed complete resolution of the oedema, no device related thrombus but a slight proximal tilting of the LAAC device without leakage could be observed. The 6-month follow-up demonstrated a stable sinus rhythm, no stroke or bleeding events were recorded. Discussion In this case of synchronous PFA-PVI procedure in AF and Watchman FLXTM device implantation, the electroporation created an acute oedema at the ridge level which at the TEE follow-up after 6 weeks was resolved. This resulted in a slightly tilted Watchman device position which was nevertheless stable and showed no leakage.

Investigation of High Frequency Irreversible Electroporation for Canine Spontaneous Primary Lung Tumor Ablation.

In this study, the feasibility of treating canine primary lung tumors with high-frequency irreversible electroporation (H-FIRE) was investigated as a novel lung cancer treatment option. H-FIRE is a minimally invasive tissue ablation modality that delivers bipolar pulsed electric fields to targeted cells, generating nanopores in cell membranes and rendering targeted cells nonviable. In the current study, canine patients (n = 5) with primary lung tumors underwent H-FIRE treatment with an applied voltage of 2250 V using a 2-5-2 µs H-FIRE waveform to achieve partial tumor ablation prior to the surgical resection of the primary tumor. Surgically resected tumor samples were evaluated histologically for tumor ablation, and with immunohistochemical (IHC) staining to identify cell death (activated caspase-3) and macrophages (IBA-1, CD206, and iNOS). Changes in immunity and inflammatory gene signatures were also evaluated in tumor samples. H-FIRE ablation was evident by the microscopic observation of discrete foci of acute hemorrhage and necrosis, and in a subset of tumors (n = 2), we observed a greater intensity of cleaved caspase-3 staining in tumor cells within treated tumor regions compared to adjacent untreated tumor tissue. At the study evaluation timepoint of 2 h post H-FIRE, we observed differential gene expression changes in the genes IDO1, IL6, TNF, CD209, and FOXP3 in treated tumor regions relative to paired untreated tumor regions. Additionally, we preliminarily evaluated the technical feasibility of delivering H-FIRE percutaneously under CT guidance to canine lung tumor patients (n = 2). Overall, H-FIRE treatment was well tolerated with no adverse clinical events, and our results suggest H-FIRE potentially altered the tumor immune microenvironment.

Combining Liver-Directed and Immunotherapy in Advanced Hepatocellular Carcinoma: A Review and Future Directions

Hepatocellular carcinoma (HCC) is a highly morbid tumor with diverse genomic heterogeneity that poses a major therapeutic barrier. Systemic immunotherapy is often considered in the treatment of advanced HCC, but immunotherapy has been limited by high rates of resistance and immune evasion. Newer studies have explored the combination of locoregional treatments (LRTs), a common approach to intermediate-stage HCC or as a bridge to transplant, with immunotherapy. This review explores the current evidence regarding combination systemic immunotherapy with locoregional transarterial, ablation, and histotripsy modalities, as well as leading theories on the mechanism of their synergistic effects. Combinations of transarterial or ablative therapy with multikinase (MKIs) or immune checkpoint inhibitors (ICIs) have been linked to prolonged survival and delayed tumor progression/recurrence, though treatment-induced adverse effects remain an important consideration. Ablation and histotripsy may augment the efficacy of immunotherapy through the abscopal effect, in which subsequent immune response to local tumor destruction may enhance immunogenic cell death, even in satellite, untreated lesions. Newer management strategies may utilize circulating tumor DNA (ctDNA) for improved surveillance and early detection of recurrence.

Application repetition and electrode-tissue contact result in deeper lesions using a pulsed-field ablation circular variable loop catheter.

Pulsed-field ablation (PFA) is a novel, myocardial-selective, non-thermal ablation modality used to target cardiac arrhythmias. Although prompt electrogram (EGM) signal disappearance is observed immediately after PFA application in the pulmonary veins, whether this finding results in adequate transmural lesions is unknown. The aim of this study is to check whether application repetition and catheter-tissue contact impact lesion formation during PFA. A circular loop PFA catheter was used to deliver repeated energy applications with various levels of contact force. A benchtop vegetal potato model and a beating heart ventricular myocardial model were utilized to evaluate the impact of application repetition, contact force, and catheter repositioning on contiguity and lesion depth. Lesion development occurred over 18 h in the vegetal model and over 6 h in the porcine model. Lesion formation was found to be dependent on application repetition and contact. In porcine ventricles, single and multiple stacked applications led to a lesion depth of 3.5 ± 0.7 and 4.4 ± 1.3 mm, respectively (P = 0.002). Furthermore, the greater the catheter-tissue contact, the more contiguous and deeper the lesions in the vegetal model (1.0 ± 0.9 mm with no contact vs. 5.4 ± 1.4 mm with 30 g of force; P = 0.0001). Pulsed-field ablation delivered via a circular catheter showed that both repetition and catheter contact led independently to deeper lesion formation. These findings indicate that endpoints for effective PFA are related more to PFA biophysics than to mere EGM attenuation.

Tissue Radiologic and Pathologic Response to Biphasic Pulsed Electric Field Technology in a Porcine Model

PurposeTo evaluate the radiologic, pathologic, and safety characteristics of a commercially available pulsed electric field (PEF) ablation system in a porcine model. Materials and MethodsMonopolar biphasic PEF ablation was delivered to the liver, kidney, and longissimus dorsi muscle through a single needle via a percutaneous or open approach with the Aliya System (Galvanize Therapeutics, Redwood City, California). Six animals were ablated and evaluated in 2 cohorts (Day 3 and Day 28). Muscle, kidney, and liver were ablated in each animal. Intraprocedural cone-beam computed tomography (CT), follow-up weekly CT, blood serology, gross pathology, and histopathology were performed to characterize the radiographic evolution and tissue response. ResultsThere were no adverse events and no findings of electrocardiographic abnormalities, and serologic values returned to baseline by Day 28. Ablation zones were visible on noncontrast CT images during follow-up. Most identified zones became radiographically smaller over time, with some fully resolved by Day 28. The relative decrease in gross ablation zone volume in the liver and skeletal muscle was 20% and 26%, respectively, whereas kidney sites grew by 22%. Ablation sites were focal and contained within the intended target tissue without extension to nontarget tissues or collateral structures. ConclusionsThe biphasic PEF system evaluated here resulted in a safe and predictable ablation response, with preservation of structural tissues in an animal model, offering an alternative to thermal ablative modalities, particularly near critical structures.

Impact of Pulsed Electric Field Ablation on His Bundle Conduction: A Preclinical Canine Study.

BACKGROUND Pulsed field ablation (PFA), as a non-thermal ablation modality, has received increasing attention. The aim of this study was to evaluate the effect of PFA upon His bundle via its implementation with different voltages on the maximum His bundle potential in canines, providing scientific basis for clinical application. MATERIAL AND METHODS Pulsed electrical field energy was delivered from a ablation catheter to the maximum His potential of 7 dogs, followed by a series of electrogram and histology assessments. RESULTS The baseline AH and HV intervals were 55.3±3.7 ms (range, 53.0-59.0 ms), and 34.9±1.3 ms (range, 34.0-36.0 ms), respectively, which were elevated to 65.0±5.4 ms (range, 59.0-70.0 ms) and 35.7±2.7 ms (range, 34.0-37.0 ms) after PFA. Before ablation and immediately after the recovery of third-degree AVB, the AH interval was prolonged (P<0.05) while the HV interval remained unchanged (P>0.05). After ablation, all 7 canines experienced transient third-degree AVB, with a voltage-dependent duration. Masson staining results revealed no apparent damage in His bundle cells. CONCLUSIONS Within a certain voltage range of pulse electric field, ablation of the maximum His potential in canines can result in transient third-degree AVB, providing a new route for guiding safe ablation of para-Hisian arrhythmia.

Desmoid fibromatosis: IR (sometimes) to the rescue for an atypical disease.

Desmoid fibromatosis is a rare locally aggressive soft tissue tumor that is characterized as benign as it cannot metastasize. It was managed until recently like sarcomas, i.e with radical surgical resection combined or not with radiotherapy. However, this approach was associated with a high rate of recurrence and significant morbidity. The management of this disease has progressively changed to a more conservative approach given the fact that desmoid fibromatosis may spontaneously stop to grow or even shrink in more than half of the cases. Should treatment be required, recent guidelines recommend choosing between systemic therapies, which include principally chemotherapy and tyrosine kinase inhibitors, and local treatments. And this is where the interventional radiologist may have an important role to treat the disease. Various ablation modalities have been reported in the literature to treat desmoid fibromatosis, notably high-intensity focused ultrasound and cryoablation. Results are promising and cryoablation is now mentioned in recent guidelines. The interventional radiologist should nevertheless apprehend the disease in its globality to understand the place of percutaneous treatments among the other therapeutic options. The goal of this review is therefore to present and discuss the role of interventional radiology (IR) in the management of DF.

Pulmonary vein isolation using pulsed field ablation vs. high-power short-duration radiofrequency ablation in paroxysmal atrial fibrillation: efficacy, safety, and long-term follow-up (PRIORI study).

Pulsed field ablation (PFA) is a novel, non-thermal, cardiac tissue-selective ablation modality. To date, radiofrequency (RF)-guided high-power short-duration (HPSD) ablation represents the gold standard besides cryo-ablation for pulmonary vein isolation (PVI). This single-centre, retrospective study investigated the efficacy of PFA-PVI vs. HPSD-RF PVI in terms of single-procedure arrhythmia-free outcome and safety in a real-world setting. Consecutive, paroxysmal atrial fibrillation (AF) patients who underwent PVI using PFA or HPSD-RF were enrolled. In group PFA, PVI was performed using a pentaspline PFA catheter. The ablation procedure in group HPSD-RF was performed with RF energy (45 W, ablation index). A total of 410 patients (group PFA, 201; group HPSD-RF, 209) were included. There was no difference between both groups regarding age, gender, and CHA2DS2-VASc score. The procedure time was significantly shorter in group PFA [61 (44-103) vs. 125 (105-143) min; P < 0.001]; fluoroscopy time and dose area product were significantly higher in group PFA [16 (13-20) vs. 4 (2-5) min; P < 0.01 and 412 (270-739) vs. 129 (58-265) μGym2; P < 0.01]. The overall complication rates were 2.9% in group PFA and 6.2% in group HPSD (P = 0.158). There was one fatal stroke in the PFA group. The 1-year Kaplan-Meier estimated freedom from any atrial tachyarrhythmia was 85% with PFA and 79% with HPSD-RF (log-rank P = 0.160). In 56 repeat ablation procedures, the PV reconnection rate was 30% after PFA and 38% after HPSD-RF (P = 0.372). Both PFA and HPSD-RF were highly efficient and effective in achieving PVI in paroxysmal AF patients. The arrhythmia-free survival is comparable. The PV reconnection rate was not different.

NIR-II light-powered core-shell prodrug nanomotors enhance cancer therapy through synergistic oxidative stress-photothermo modulation

Near-infrared-II (NIR-II) photothermal therapy is emerging as a cutting-edge modality for tumor ablation due to its good biosafety, high penetration ability and spatiotemporal controllability. Despite efforts, establishing a link between cellular metabolic regulation and photothermal performance is still promising in synergistic cancer therapy. Herein, we developed a core-shell semiconducting polymer@metal-phenolic network (SP@GFP) nanomotor by assembling diphenol-terminated cisplatin prodrug ligand (cPt-DA) and iron (III) (Fe3+) through metal coordination on SP particles in the presence of GOx and DSPE-PEG-cRGD, for NIR-II-propelled self-propulsion and synergistic cancer therapy. Remotely driving the SP@GFP nanomotor with an NIR-II laser through a thermophoresis mechanism would allow for in-depth penetration and accumulation. The synergistic photothermal effect and continuous Fe2+-mediated ROS generation of SP@GFP nanomotor could activate photothermal, chemotherapeutic effects and ferroptosis pathway for cancer cells through reshaping cellular metabolic pathways (HSP and GPX4). By combining the concepts of chemotherapeutic prodrugs, catalytic ROS generation, photothermal response and cellular metabolic regulation, the NIR-II laser-controlled core-shell SP@GFP nanomotor displayed improved outcomes for enhanced cancer therapy through synergistic oxidative stress-photothermo modulation. Statement of significance•A NIR-II-powered core-shell SP@GFP prodrug nanomotor was constructed through metal coordination assembly for enhanced cancer therapy;•NIR-II laser propelled the propulsion of SP@GFP nanomotor through thermophoresis mechanism for in depth penetration and accumulation.•Therapeutic outcomes were improved through synergistic modulating oxidative stress and photothermal performance.

Efficacy and safety of a novel hexaspline pulsed field ablation system in patients with paroxysmal atrial fibrillation: the PLEASE-AF study.

Pulsed field ablation (PFA) is an emerging non-thermal ablative modality demonstrating considerable promise for catheter ablation of atrial fibrillation (AF). However, these PFA trials have almost universally included only Caucasian populations, with little data on its effect on other races/ethnicities. The PLEASE-AF trial sought to study the 12-month efficacy and the safety of a multi-electrode hexaspline PFA catheter in treating a predominantly Asian/Chinese population of patients with drug-refractory paroxysmal AF. Patients underwent pulmonary vein (PV) isolation (PVI) by delivering different pulse intensities at the PV ostium (1800 V) and atrium (2000 V). Acute success was defined as no PV potentials and entrance/exit conduction block of all PVs after a 20-min waiting period. Follow-up at 3, 6, and 12 months included 12-lead electrocardiogram and 24-h Holter examinations. The primary efficacy endpoint was 12-month freedom from any atrial arrhythmias lasting at least 30 s. The cohort included 143 patients from 12 hospitals treated by 28 operators: age 60.2 ± 10.0 years, 65.7% male, Asian/Chinese 100%, and left atrial diameter 36.6 ± 4.9 mm. All PVs (565/565, 100%) were successfully isolated. The total procedure, catheter dwell, total PFA application, and total fluoroscopy times were 123.5 ± 38.8 min, 63.0 ± 30.7 min, 169.7 ± 34.6 s, and 27.3 ± 10.1 min, respectively. The primary endpoint was observed in 124 of 143 patients (86.7%). One patient (0.7%) developed a small pericardial effusion 1-month post-procedure, not requiring intervention. The novel hexaspline PFA catheter demonstrated universal acute PVI with an excellent safety profile and promising 12-month freedom from recurrent atrial arrhythmias in an Asian/Chinese population with paroxysmal AF. ClinicalTrials.gov Identifier: NCT05114954.