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Heart Rhythm O2 Jan 2023High-power, short-duration (HPSD) radiofrequency ablation (RFA) may reduce ablation time. Concerns that catheter-mounted thermocouples (TCs) can underestimate tissue...
BACKGROUND
High-power, short-duration (HPSD) radiofrequency ablation (RFA) may reduce ablation time. Concerns that catheter-mounted thermocouples (TCs) can underestimate tissue temperature, resulting in elevated risk of steam pop formation, potentially limit widespread adoption of HPSD ablation.
OBJECTIVE
The purpose of this study was to compare the safety and efficacy of HPSD and low-power, long-duration (LPLD) RFA in the context of pulmonary vein isolation (PVI).
METHODS
An open-irrigated ablation catheter with a contact force sensor and a flexible-tip electrode containing a TC at its distal end (TactiFlex Ablation Catheter, Sensor Enabled, Abbott) was used to isolate the left pulmonary veins (PVs) in 12 canines with HPSD RFA (50 W for 10 seconds) and LPLD RFA (30 W for a maximum of 60 seconds). PVI was assessed at 30 minutes and 28 ± 3 days postablation. Computed tomographic scans were performed to assess PV stenosis after RFA. Lesions were evaluated with histopathology.
RESULTS
A total of 545 ablations were delivered: 252 with LPLD (0 steam pops) and 293 with HPSD RFA (2 steam pops) ( = .501). Ablation time required to achieve PVI was >3-fold shorter for HPSD than for LPLD RFA ( = .001). All 24 PVs were isolated 30 minutes after ablation, with 12/12 LPLD-ablated and 11/12 HPSD-ablated PVs still isolated at follow-up. Histopathology revealed transmural ablations for HPSD and LPLD RFA. No major adverse events occurred.
CONCLUSION
An investigational ablation catheter effectively delivered RFA lesions. Ablation time required to achieve PVI with HPSD with this catheter was >3-fold shorter than with LPLD RFA.
PubMed: 36713045
DOI: 10.1016/j.hroo.2022.10.009 -
International Journal of Hyperthermia :... 2021Microwave ablation (MWA) provides an effective treatment of lung and liver tumors but suffers from a lack of reproducibility of ablation size among currently available...
PURPOSE
Microwave ablation (MWA) provides an effective treatment of lung and liver tumors but suffers from a lack of reproducibility of ablation size among currently available technologies. evaluations are far removed from clinical practices because of uninfused tissue. This study is preclinical testing of a new MWA system on swine lungs and liver.
MATERIALS AND METHODS
All ablations were performed under CT guidance and multiple algorithms were tested with a power of 50, 75, and 100 W for durations of 3, 5, 8, 10, and 15 min. A 3 D-evaluation of the ablation zone was carried out using enhanced-CT. The sphericity index, coefficients of variation, and energy efficiency (which corresponds to the volume yield according to the power supplied) were calculated.
RESULTS
Fifty liver and 48 lung ablations were performed in 17 swine. The sphericity index varies from 0.50 to 0.80 for liver ablations and from 0.40 to 0.69 for lung ablations. The coefficient of variation was below 15% for 4/5 and 4/8 protocols for lung and liver ablations, respectively. The energy efficiency seems to decrease with the duration of the ablation from 0.60 × 10 cm/J (75 W, 3 min) to 0.26 × 10 cm/J (100 W, 15 min) in the liver and from 0.57 × 10 cm/J (50 W, 10 min) to 0.42 × 10 cm/J (100 W, 12 min) in the lungs.
CONCLUSION
A shorter treatment time provides the best energy efficiency, and the best reproducibility is obtained for a 10 min treatment duration. The system tested provides an interesting reproducibility in both lung and liver measurements. Our results may help interventional radiologists in the optimal selection of treatment parameters.
Topics: Ablation Techniques; Animals; Catheter Ablation; Humans; Liver; Lung; Microwaves; Reproducibility of Results; Swine; Tomography, X-Ray Computed
PubMed: 34353206
DOI: 10.1080/02656736.2021.1961883 -
Hepatic Oncology Dec 2022To evaluate the safety and efficacy of uncooled TATO microwave ablation (MWA) for primary and metastatic liver cancer.
AIM
To evaluate the safety and efficacy of uncooled TATO microwave ablation (MWA) for primary and metastatic liver cancer.
MATERIALS & METHODS
This was a retrospective study on percutaneous liver ablations performed with TATO MWA. Twenty-five ablations were performed; 11 (44%) were performed for hepatocellular carcinoma, 14 (56%) for colorectal carcinoma, gastric and pancreatic metastases.
RESULTS
Adverse events were reported only in one (4%) ablation: an abscess that was observed in the ablated area and was resolved with a percutaneous drainage and antibiotic therapy. Local tumor control rate was 92% at the 3-month follow-up.
CONCLUSION
TATO MWA was safe and effective with high reproducibility in treating primary and secondary liver cancer with satisfactory technical and clinical outcomes.
PubMed: 37009421
DOI: 10.2217/hep-2022-0002 -
JACC. Clinical Electrophysiology Mar 2021The aims of this study were to establish criteria for identifying ligament of Marshall (LOM) connections that are responsible for pulmonary vein isolation (PVI) failure,...
OBJECTIVES
The aims of this study were to establish criteria for identifying ligament of Marshall (LOM) connections that are responsible for pulmonary vein isolation (PVI) failure, assess their incidence, and determine if they can be targeted by focal endocardial ablation at the anterior carina of the left superior pulmonary vein (LSPV).
BACKGROUND
Wide antral ablation of the left pulmonary veins (PVs) may not achieve PVI, sometimes requiring empirical ablation of the PV carina. The mechanism could be due to epicardial conduction along the LOM, which courses adjacent to the anterior carina.
METHODS
In patients undergoing radiofrequency ablation for atrial fibrillation, if wide ablation of the left PV did not achieve isolation, bidirectional mapping was performed. A presumptive LOM connection was diagnosed if the earliest entrance was mapped to the anterior LSPV, while the earliest exit was mapped inferior to the left inferior PV. Focal ablation at the LSPV anterior carina was performed, even if not at the site of earliest entrance activation. The primary endpoint was successful PVI immediately after ablation.
RESULTS
The study included 455 consecutive patients who underwent 570 procedures, of which 364 were first-time ablations. Presumptive LOM connections were identified in 48 procedures (8.4%) and in 41 patients (11.2%) undergoing first-time ablation and were successfully ablated at the anterior carina of the LSPV in 47 of 48 procedures (98%).
CONCLUSIONS
LOM connections may be a common cause of PVI failure and can be easily identified and reliably ablated with focal endocardial ablation at the anterior LSPV carina.
Topics: Atrial Fibrillation; Catheter Ablation; Endocardium; Humans; Ligaments; Pulmonary Veins
PubMed: 33736749
DOI: 10.1016/j.jacep.2020.08.027 -
Journal of Cardiovascular... Jul 2022Pulsed-field ablation (PFA), an ablative method that causes cell death by irreversible electroporation, has potential safety advantages over radiofrequency ablation and...
In vivo porcine characterization of atrial lesion safety and efficacy utilizing a circular pulsed-field ablation catheter including assessment of collateral damage to adjacent tissue in supratherapeutic ablation applications.
INTRODUCTION
Pulsed-field ablation (PFA), an ablative method that causes cell death by irreversible electroporation, has potential safety advantages over radiofrequency ablation and cryoablation. Pulmonary vein (PV) isolation was performed in a porcine model to characterize safety and performance of a novel, fully-integrated biphasic PFA system comprising a multi-channel generator, variable loop circular catheter, and integrated PFA mapping software module.
METHODS
Eight healthy porcine subjects were included. To evaluate safety, multiple ablations were performed, including sites not generally targeted for therapeutic ablation, such as the right inferior PV lumen, right superior PV ostium, and adjacent to the esophagus and phrenic nerve. To evaluate the efficacy, animals were recovered, followed for 30(±3) days, then re-mapped. Gross pathological and histopathological examinations assessed procedural injuries, chronic thrombosis, tissue ablation, penetration depth, healing, and inflammatory response.
RESULTS
All eight animals survived follow-up. PV narrowing was not observed acutely nor at follow-up, even when ablation was performed deep to the PV ostium. No injury was seen grossly or histologically in adjacent structures. All PVs were durably isolated, confirmed by bidirectional block at re-map procedure. Histological examination showed complete, transmural necrosis around the circumference of the ablated section of right PVs.
CONCLUSION
This preclinical evaluation of a fully-integrated PFA system demonstrated effective and durable ablation of cardiac tissue and PV isolation without collateral damage to adjacent structures, even when ablation was performed in more extreme settings than those used therapeutically. Histological staining confirmed complete transmural cell necrosis around the circumference of the PV ostium at 30 days.
Topics: Animals; Atrial Fibrillation; Catheter Ablation; Catheters; Heart Atria; Humans; Necrosis; Pulmonary Veins; Swine; Treatment Outcome
PubMed: 35510408
DOI: 10.1111/jce.15522 -
Environmental Research Jan 2021Human Papillomavirus (HPV) is associated with development of oropharyngeal cancer. Aim of this review was to assess airborne transmission risk of infectious particles... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Human Papillomavirus (HPV) is associated with development of oropharyngeal cancer. Aim of this review was to assess airborne transmission risk of infectious particles from HPV lesions to airway mucosa of medical staff during established ablation procedures.
METHODS
A systematic review of human and animal studies, published before 09/2020, relevant to airborne HPV transmission. Controlled studies reporting prevalence of HPV-associated upper airway (nasal/oral/pharyngeal) disease in staff performing ablation procedures (laser, loop electrosurgical excision [LEEP], cryosurgery) on HPV lesions were included in meta-analysis. Additionally, we aimed for a comprehensive systematic overview of studies regarding occupational risk of airborne HPV transmission and safety measures during ablation procedures.
RESULTS
A total of n = 30 original studies report outcomes related to HPV transmission risk in medical staff conducting ablation procedures. HPV DNA detection in ablation smoke (n = 7), matching HPV genotypes on ablated HPV lesions and face/airways of medical staff after ablation (n = 2), and evidence for infectivity of papillomavirus in ablation smoke (n = 3, animal models only) were reported. Three case reports describe occupational HPV disease of upper airway mucosa. Three controlled studies assessed warts (in CO laser-users only); when pooling all controls (general population, non-laser users), nasal/oral/pharyngeal lesion sites were more common amongst laser-users (OR = 5.75; 95%CI[1.55, 21.38]; p < .001).
DISCUSSION
Airborne HPV dispersal with matching "high-risk" HPV-genotypes in airways of medical staff after ablations (LEEP and CO-laser) and cases of HPV-associated upper airways neoplasms based on exposure to laser and LEEP smoke are documented. Upper airway mucosa is a more common anatomical site for warts in CO laser users compared to controls. Simple safety measures greatly reduce HPV contamination and transmission risk.
Topics: Alphapapillomavirus; Animals; Humans; Papillomaviridae; Papillomavirus Infections; Prevalence
PubMed: 33181134
DOI: 10.1016/j.envres.2020.110437 -
Integrative Organismal Biology (Oxford,... 2022The mechanoreceptive lateral line system in fish is composed of neuromasts containing hair cells, which can be temporarily ablated by aminoglycoside antibiotics and...
The mechanoreceptive lateral line system in fish is composed of neuromasts containing hair cells, which can be temporarily ablated by aminoglycoside antibiotics and heavy metal ions. These chemicals have been used for some time in studies exploring the functional role of the lateral line system in many fish species. However, little information on the relative effectiveness and rate of action of these chemicals for ablation is available. In particular, aminoglycoside antibiotics are thought to affect canal neuromasts, which sit in bony or trunk canals, differently from superficial neuromasts, which sit directly on the skin. This assumed ablation pattern has not been fully quantified for commonly used lateral line ablation agents. This study provides a detailed characterization of the effects of two aminoglycoside antibiotics, streptomycin sulfate and neomycin sulfate, and a heavy metal salt, cobalt (II) chloride hexahydrate (CoCl), on the ablation of hair cells in canal and superficial neuromasts in the giant danio () lateral line system, as a model for adult teleost fishes. We also quantified the regeneration of hair cells after ablation using CoCl and gentamycin sulfate to verify the time course to full recovery, and whether the ablation method affects the recovery time. Using a fluorescence stain, 4-Di-2-ASP, we verified the effectiveness of each chemical by counting the number of fluorescing canal and superficial neuromasts present throughout the time course of ablation and regeneration of hair cells. We found that streptomycin and neomycin were comparably effective at ablating all neuromasts in less than 12 h using a 250 μM dosage and in less than 8 h using a 500 μM dosage. The 500 μM dosage of either streptomycin or neomycin can ablate hair cells in superficial neuromasts within 2-4 h, while leaving those in canal neuromasts mostly intact. CoCl (0.1 mM) worked the fastest, ablating all of the hair cells in less than 6 h. Complete regeneration of the neuromasts in the lateral line system took 7 days regardless of chemicals used to ablate the hair cells. This study adds to the growing knowledge in hearing research about how effective specific chemicals are at ablating hair cells in the acoustic system of vertebrates.
PubMed: 35359665
DOI: 10.1093/iob/obac012 -
Analytical Cellular Pathology... 2019Hepatocellular carcinoma (HCC) is the most common primary cancer of the liver. Hepatectomy and liver transplantation (LT) are regarded as the radical treatment, but... (Review)
Review
Hepatocellular carcinoma (HCC) is the most common primary cancer of the liver. Hepatectomy and liver transplantation (LT) are regarded as the radical treatment, but great majority of patients are already in advanced stage on the first diagnosis and lose the surgery opportunity. Multifarious image-guided interventional therapies, termed as locoregional ablations, are recommended by various HCC guidelines for the clinical practice. Transarterial chemoembolization (TACE) is firstly recommended for intermediate-stage (Barcelona Clinic Liver Cancer (BCLC) B class) HCC but has lower necrosis rates. Radiofrequency ablation (RFA) is effective in treating HCCs smaller than 3 cm in size. Microwave ablation (MWA) can ablate larger tumor within a shorter time. Combination of TACE with RFA or MWA is effective and promising in treating larger HCC lesions but needs more clinical data to confirm its long-term outcome. The combination of TACE and RFA or MWA against hepatocellular carcinoma needs more clinical data for a better strategy. The characters and advantages of TACE, RFA, MWA, and TACE combined with RFA or MWA are reviewed to provide physician a better background on decision.
Topics: Carcinoma, Hepatocellular; Chemoembolization, Therapeutic; Humans; Liver Neoplasms; Microwaves; Radiofrequency Ablation
PubMed: 31534899
DOI: 10.1155/2019/8619096 -
Cardiovascular and Interventional... Jun 2021To investigate the performance of two microwave ablation (MWA) systems regarding ablation volume, ablation shape and variability.
PURPOSE
To investigate the performance of two microwave ablation (MWA) systems regarding ablation volume, ablation shape and variability.
MATERIALS AND METHODS
In this ex vivo study, the Emprint and Amica MWA systems were used to ablate porcine livers at 4 different settings of time and power (3 and 5 minutes at 60 and 80 Watt). In total, 48 ablations were analysed for ablation size and shape using Vitrea Advanced Visualization software after acquisition of a 7T MRI scan.
RESULTS
Emprint ablations were smaller (11,1 vs. 21,1 mL p < 0.001), more spherical (sphericity index of 0.89 vs. 0.59 p < 0.001) and showed less variability than Amica ablations. In both systems, longer ablation time and higher power resulted in significantly larger ablation volumes.
CONCLUSION
Emprint ablations were more spherical, and the results showed a lower variability than those of Amica ablations. This comes at the price of smaller ablation volumes.
Topics: Ablation Techniques; Animals; Catheter Ablation; Liver; Microwaves; Models, Animal; Reproducibility of Results; Swine
PubMed: 33462682
DOI: 10.1007/s00270-020-02742-9 -
Frontiers in Medical Technology 2022This proof-of-concept study aimed to investigate atrial and ventricular lesion formation by a 20-mm linear laser ablation catheter, regarding lesion depth and tissue...
AIM
This proof-of-concept study aimed to investigate atrial and ventricular lesion formation by a 20-mm linear laser ablation catheter, regarding lesion depth and tissue damage.
METHODS
In total, 6 female swines underwent standard femoral vein access to introduce a novel 20-mm linear laser ablation catheter in the right atrium to perform endocardial cavotricuspid isthmus (CTI) ablations. The navigation took place under fluoroscopy with additional visualization by intracardiac echocardiograph. a sternotomy, epicardial ablations were performed on the surface of the left ventricle (LV), right ventricle (RV), and right atrial appendage (RAA). Procedural safety was assessed by registration of intraprocedural adverse events and by macroscopic examination of the excised hearts for the presence of charring or tissue disruption at the lesion site.
RESULTS
Altogether 39 lesions were created, including 8 endocardial CTI (mean lesion length 20.6 ± 1.65 mm), 26 epicardial ventricle (mean lesion length LV: 25.3 ± 1.35 mm, RV: 24.9 ± 2.40 mm), and 5 epicardial appendage ablations (mean lesion length RAA: 26.0 ± 3.16 mm). Transmurality was achieved in all CTI and atrial appendage ablations, in 62% of the RV ablations and in none of the LV ablations. No perforation or steam pop occurred, and no animal died during the procedure.
CONCLUSION
In this porcine study, the 20-mm linear laser ablation catheter has shown excellent results for endocardial cavotricuspid isthmus ablation, and it resulted in acceptable lesion depth during atrial and ventricular epicardial ablation. The absence of tissue charring, steam pops, or microbubbles under the experimental conditions suggests a high degree of procedural safety.
PubMed: 35387364
DOI: 10.3389/fmedt.2022.834856