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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 -
Journal of Cardiovascular... Feb 2021Ganglionated plexuses (GPs) are implicated in atrial fibrillation (AF). Endocardial high-frequency stimulation (HFS) delivered within the local atrial refractory period... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Ganglionated plexuses (GPs) are implicated in atrial fibrillation (AF). Endocardial high-frequency stimulation (HFS) delivered within the local atrial refractory period can trigger ectopy and AF from specific GP sites (ET-GP). The aim of this study was to understand the role of ET-GP ablation in the treatment of AF.
METHODS
Patients with paroxysmal AF indicated for ablation were recruited. HFS mapping was performed globally around the left atrium to identify ET-GP. ET-GP was defined as atrial ectopy or atrial arrhythmia triggered by HFS. All ET-GP were ablated, and PVs were left electrically connected. Outcomes were compared with a control group receiving pulmonary vein isolation (PVI). Patients were followed-up for 12 months with multiple 48-h Holter ECGs. Primary endpoint was ≥30 s AF/atrial tachycardia in ECGs.
RESULTS
In total, 67 patients were recruited and randomized to ET-GP ablation (n = 39) or PVI (n = 28). In the ET-GP ablation group, 103 ± 28 HFS sites were tested per patient, identifying 21 ± 10 (20%) GPs. ET-GP ablation used 23.3 ± 4.1 kWs total radiofrequency (RF) energy per patient, compared with 55.7 ± 22.7 kWs in PVI (p = <.0001). Duration of procedure was 3.7 ± 1.0 and 3.3 ± 0.7 h in ET-GP ablation group and PVI, respectively (p = .07). Follow-up at 12 months showed that 61% and 49% were free from ≥30 s of AF/AT with PVI and ET-GP ablation respectively (log-rank p = .27).
CONCLUSIONS
It is feasible to perform detailed global functional mapping with HFS and ablate ET-GP to prevent AF. This provides direct evidence that ET-GPs are part of the AF mechanism. The lower RF requirement implies that ET-GP targets the AF pathway more specifically.
Topics: Atrial Fibrillation; Catheter Ablation; Electrocardiography, Ambulatory; Heart Atria; Humans; Pulmonary Veins; Recurrence; Treatment Outcome
PubMed: 33421265
DOI: 10.1111/jce.14870 -
Journal of Immunology (Baltimore, Md. :... Apr 2023CMV infection alters NK cell phenotype and function toward a more memory-like immune state. These cells, termed adaptive NK cells, typically express CD57 and NKG2C but...
CMV infection alters NK cell phenotype and function toward a more memory-like immune state. These cells, termed adaptive NK cells, typically express CD57 and NKG2C but lack expression of the FcRγ-chain (gene: FCER1G, FcRγ), PLZF, and SYK. Functionally, adaptive NK cells display enhanced Ab-dependent cellular cytotoxicity (ADCC) and cytokine production. However, the mechanism behind this enhanced function is unknown. To understand what drives enhanced ADCC and cytokine production in adaptive NK cells, we optimized a CRISPR/Cas9 system to ablate genes from primary human NK cells. We ablated genes that encode molecules in the ADCC pathway, such as FcRγ, CD3ζ, SYK, SHP-1, ZAP70, and the transcription factor PLZF, and tested subsequent ADCC and cytokine production. We found that ablating the FcRγ-chain caused a modest increase in TNF-α production. Ablation of PLZF did not enhance ADCC or cytokine production. Importantly, SYK kinase ablation significantly enhanced cytotoxicity, cytokine production, and target cell conjugation, whereas ZAP70 kinase ablation diminished function. Ablating the phosphatase SHP-1 enhanced cytotoxicity but reduced cytokine production. These results indicate that the enhanced cytotoxicity and cytokine production of CMV-induced adaptive NK cells is more likely due to the loss of SYK than the lack of FcRγ or PLZF. We found the lack of SYK expression could improve target cell conjugation through enhanced CD2 expression or limit SHP-1-mediated inhibition of CD16A signaling, leading to enhanced cytotoxicity and cytokine production.
Topics: Humans; Syk Kinase; Cytomegalovirus; CRISPR-Cas Systems; Killer Cells, Natural; Cytomegalovirus Infections; Cytokines; Antibody-Dependent Cell Cytotoxicity
PubMed: 36881874
DOI: 10.4049/jimmunol.2200488 -
Journal of Cancer Research and... Apr 2022To evaluate the safety and effectiveness of open superconducting magnetic resonance (MR)-guided microwave ablation of liver tumors and explore feasibility of real-time...
OBJECTIVE
To evaluate the safety and effectiveness of open superconducting magnetic resonance (MR)-guided microwave ablation of liver tumors and explore feasibility of real-time imaging sequence-guided needle insertion technique.
MATERIALS AND METHODS
Medical records of December 2019-May 2021 of microwave ablations of liver tumors under MR guidance in XX University Cancer Center were reviewed. Real-time imaging-guided puncture technique refers to real-time insertion and adjusting the position of a microwave applicator under a fast imaging sequence. The safety and efficacy of the procedure among the enrolled patients were assessed.
RESULTS
Twenty-six patients underwent 27 procedures, with 30 lesions ablated (long diameter: 1.51 ± 0.81 cm, short diameter: 1.30 ± 0.61 cm). There were 20 cases of primary liver cancer and 10 of liver metastases. All lesions were identified by MR imaging (MRI), and all procedures were successfully performed using the finger positioning method for puncture sites. Five patients underwent real-time guided needle insertion techniques. Further, the microwave applicators reached the target position at once, and the entire insertion process was completed within 3 min. The completion rate of the real-time guided needle insertion technology was 100%, and 25 (92.6%) patients had minor complications. No severe complications were observed, and the technical success rate of 30 MRI-guided lesions was 100%. Finally, the complete ablation rate of the MRI-guided ablation after the first procedure was 93.1%.
CONCLUSION
Open MR-guided microwave ablation is safe and effective in treating liver tumors. Furthermore, real-time imaging sequence-guided puncture technique under MRI is feasible and efficient.
Topics: Carcinoma, Hepatocellular; Feasibility Studies; Humans; Liver Neoplasms; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Microwaves
PubMed: 35645104
DOI: 10.4103/jcrt.jcrt_1659_21 -
Cardiovascular and Interventional... Nov 2021To compare laser ablation (LA) zone dimensions at two predetermined energy parameters to cover a theoretical 10 mm zone + 2 mm margin in a thyroid swine model.
BACKGROUND
To compare laser ablation (LA) zone dimensions at two predetermined energy parameters to cover a theoretical 10 mm zone + 2 mm margin in a thyroid swine model.
METHODS
Approval of the Institutional Animal Care and Use Committee was obtained. After hydrodissection, an ultrasound-guided LA (Elesta Echolaser X4 with Orblaze technology, 1064 nm) was performed in the periphery of the thyroid in 10 swine. Two cohorts were established to ablate a region of 10mm diameter with 2mm margin based on manufacturer's ex vivo data (n= 5 at 3W/1400J and n= 5 at 3W/1800J). The ablation zone was measured on contrast-enhanced computed tomography (CT) and compared to the pathological specimen. Euthanasia was performed 48 hours following ablation.
RESULTS
All ablations in the 3W/1800J group achieved a diameter of 12 mm ± 1 mm in three dimensions. In the 3W/1400J group, 1 ablation reached 12 mm ± 1 mm in 2 dimensions and 4 ablations reached this size in one dimension. Maximum diameter was higher in the 3W/1800J compared to the 3W/1400J group, both on histology (1.46 cm ± 0.05 vs. 1.1 cm ± 0.0, p< 0.01) and CT (1.52 cm ± 0.04 vs. 1.18 cm ± 0.04, p< 0.01). Similar results were obtained regarding volumes, both on histology (1.12 mL ± 0.13 vs. 0.57 mL ± 0.06, p< 0.01) and CT (1.24 mL ± 0.13 vs. 0.59 mL ± 0.07, p< 0.01). Histology showed coagulation necrosis and correlated well with CT measurements.
CONCLUSION
Optimal parameters to obtain a LA zone of 10 mm with 2 mm margin utilizing a single needle are 3W/1800J.
Topics: Ablation Techniques; Animals; Catheter Ablation; Laser Therapy; Swine; Thyroid Gland; Ultrasonography; Ultrasonography, Interventional
PubMed: 34254175
DOI: 10.1007/s00270-021-02915-0 -
International Journal of Hyperthermia :... 2021To explore the feasibility of microwave ablation (MWA) of the vertebral growth plate as a minimally invasive treatment for early-onset scoliosis.
PURPOSE
To explore the feasibility of microwave ablation (MWA) of the vertebral growth plate as a minimally invasive treatment for early-onset scoliosis.
MATERIALS AND METHODS
One side of the L1-L3 vertebral growth plates were ablated using different MWA powers. Ablation safety and size were examined. Subsequently, L1-L3 vertebral growth plates were ablated on one side for 40 s at 20 W. At 2, 4, and 6 weeks after the ablation, growth changes of the spine were observed.
RESULTS
No piglets died during and after ablation, and all had modified Tarlov Grade 5. The safe MWA time (time for safely ablating the vertebral growth plate) was 17.0 ± 1.5 s at 50 W, 23.0 ± 2.3 s at 40 W, 31.0 ± 3.1 s at 30 W, 47.0 ± 3.7 s at 20 W, 70.0 ± 4.2 s at 15 W, and 158.0 ± 5.0 s at 10 W. With power <15 W, the vertebral growth plate could not be effectively ablated within the safe ablation time. Within the safe ablation times, the MWA size on hematoxylin and eosin slices on a transverse diameter was between 7 and 10 mm; and that on longitudinal diameter was mainly determined by the ablation needle length. Moreover, the growth plate and annulus fibrosus on the ablated side grew poorly over time, the vertebral body showed significant wedge-shaped changes, and the spine showed significant unbalanced growth.
CONCLUSION
MWA of the vertebral growth plate can be performed safely when accompanied with appropriate thermometry, and could be a new minimally invasive strategy in regulating spine growth.
Topics: Catheter Ablation; Feasibility Studies; Growth Plate; Microwaves; Radiofrequency Ablation
PubMed: 34396870
DOI: 10.1080/02656736.2021.1964619 -
Circulation Journal : Official Journal... Feb 2019Automated ablation lesion annotation with optimal settings for parameters including contact force (CF) and catheter stability may be effective for achieving durable... (Comparative Study)
Comparative Study
BACKGROUND
Automated ablation lesion annotation with optimal settings for parameters including contact force (CF) and catheter stability may be effective for achieving durable pulmonary vein isolation. Methods and Results: We retrospectively examined 131 consecutive patients who underwent initial catheter ablation (CA) for paroxysmal atrial fibrillation (PAF) by automatic annotation system (VISITAG module)-guided radiofrequency CA (RFCA) (n=61) and 2nd-generation cryoballoon ablation (CBA) (n=70) in terms of safety and long-term efficacy. The automatic annotation criteria for the RFCA group were as follows: catheter stability range of motion ≤1.5 mm, duration ≥5 s, and CF ≥5 g. We ablated for >20 s with a force-time integral >150 gs at each site, before moving to the next site. Each interlesion distance was <6 mm. Procedural complications were more frequent in the CBA group (1.6% vs. 10.0%, P=0.034). Across a median follow-up of 2.98 years, 88.5% and 70.0% of patients in the RFCA and CBA groups, respectively, were free from recurrence (log-rank test, P=0.0039). There was also a significant difference in favor of RFCA with respect to repeat ablations (3.3% vs. 24.3%, log-rank test, P=0.0003).
CONCLUSIONS
RF ablation guided by an automated algorithm that includes CF and catheter stability parameters showed better long-term outcomes than CBA in the treatment of patients with PAF without increasing complications.
Topics: Aged; Algorithms; Atrial Fibrillation; Automation; Catheter Ablation; Cryosurgery; Female; Humans; Male; Middle Aged; Recurrence; Retrospective Studies; Treatment Outcome
PubMed: 30726801
DOI: 10.1253/circj.CJ-18-1035 -
Journal of Cancer Research and... 2019This study aimed to evaluate the safety and efficacy of thermal ablation in treating low-risk unifocal papillary thyroid microcarcinoma (PTMC).
OBJECTIVE
This study aimed to evaluate the safety and efficacy of thermal ablation in treating low-risk unifocal papillary thyroid microcarcinoma (PTMC).
MATERIALS AND METHODS
Patients with unifocal PTMC were enrolled in this study, and thermal ablations were performed. Contrast-enhanced ultrasound was used to estimate the extent of ablation immediately after thermal ablation; complications were recorded. The size and volume of the ablated area and thyroid hormones were measured, and the clinical evaluations were performed at 1, 3, 6, 12, and 18 months after thermal ablation. From July 2016 to July 2017, the prospective study was conducted involving 107 patients. Thermal ablation was well tolerated without serious complications.
RESULTS
Compared with the volume immediately after thermal ablation, the mean volume reduction ratio (VRR) of ablated lesions was 0.457 ± 0.218 (range: 0.040-0.979), 0.837 ± 0.150 (range: 0.259-1), 0.943 ± 0.090 (range: 0.491-1), 0.994-0.012 (range: 0.938-1), and 0.999 ± 0.002 (range: 0.992-1) at 1, 3, 6, 12, and 18 months after thermal ablation, respectively. Significant differences in the VRR were found between every two follow-up visits (P < 0.01). Results of patients' thyroid function test before thermal ablation and at 1 month after thermal ablation were normal, and no significant differences were observed (P > 0.05). No tumor regrowth, local recurrence, or distant metastases were detected during follow-up visits.
CONCLUSION
Thermal ablation is a short-term safe and effective method in treating low-risk small PTMCs, which can be considered a potential alternative therapy for patients with PTMC.
Topics: Ablation Techniques; Adult; Carcinoma, Papillary; Feasibility Studies; Female; Humans; Hyperthermia, Induced; Male; Microwaves; Middle Aged; Pilot Projects; Postoperative Complications; Radiofrequency Ablation; Surgery, Computer-Assisted; Thyroid Neoplasms; Treatment Outcome; Tumor Burden; Ultrasonography; Young Adult
PubMed: 31939432
DOI: 10.4103/jcrt.JCRT_214_19 -
Diagnostic and Interventional Imaging May 2019The purpose of this study was to investigate the development and evolution of the microwave ablation (MWA) lesion in the normal lung by using a swine model at various... (Comparative Study)
Comparative Study
PURPOSE
The purpose of this study was to investigate the development and evolution of the microwave ablation (MWA) lesion in the normal lung by using a swine model at various time points and to compare post-procedural computed tomography (CT) and gross pathologic findings during the first month post-ablation.
MATERIALS AND METHODS
Twenty-seven percutaneous MWA procedures were performed on swine lungs at 100W for either 2min (low dose, 18 ablations) or 10min (high dose, 9 ablations). Animals were sacrificed at either 2 days (n=5) or 28 days (n=5) after ablation. All animals underwent CT imaging immediate post-treatment and prior to sacrifice, with additional imaging at 7 and 14 days for the 28-day cohort. After euthanasia, lungs and trachea were removed en bloc and underwent gross pathology analysis.
RESULTS
In both dose treatment groups, CT measurements of the ablation zone were maximum at Day 7 (low dose: 7.50±3.08 cm; high dose: 24.87±11.34 cm) and significantly larger compared to the immediate post-ablation measurements (low dose: 2.54±1.81 cm; P=0.00011; high dose: 9.14±3.42 cm; P=0.00374). No significant differences in dimensions were observed between CT and gross pathologic images for both high and low dose ablations in both cohorts.
CONCLUSION
The treatment zone following MWA in the lung can vary in the sub-acute setting, achieving largest size at 7 days post-treatment. Furthermore, measurements from CT closely matched with gross pathologic ablation size.
Topics: Ablation Techniques; Animals; Contrast Media; Disease Models, Animal; Follow-Up Studies; Lung; Lung Neoplasms; Microwaves; Pneumothorax; Postoperative Complications; Swine; Tomography, X-Ray Computed
PubMed: 30581098
DOI: 10.1016/j.diii.2018.10.008 -
HPB : the Official Journal of the... Jul 2022Radiofrequency ablation (RFA) is subject to "heat-sink" effects, particularly for treatment of tumors adjacent to major vessels.
BACKGROUND
Radiofrequency ablation (RFA) is subject to "heat-sink" effects, particularly for treatment of tumors adjacent to major vessels.
METHODS
In this retrospective study, 104 patients with 137 tumors (40 HCC, 10 ICC and 54 metastatic liver tumors) close to (≤1 cm from) the hepatic venous confluence underwent stereotactic RFA (SRFA) between June 2003 and June 2018. Median tumor size was 3.7 cm (1.4-8.5) for HCC, 6.4 cm (0.5-11) for ICC and 3.8 cm (0.5-13) for metastases. Endpoints comprised safety, local tumor control, overall and disease-free survival.
RESULTS
The overall major complication rate was 16.0% (20/125 ablations), where 8 (40%) were successfully treated by the interventional radiologist in the same anesthetic session and did not prolong hospital stay. 134/137 (97.8%) tumors were successfully ablated at initial SRFA. Local recurrence (LR) developed in 19/137 tumors (13.9%). The median and overall survival (OS) rates at 1-, 3-, and 5- years from the date of the first SRFA were 51.5 months, 73.5%, 67.0%, and 49.7% for HCC, 14.6 months, 60.0%, 32.0% and 32.0% for ICC and 38.1 months, 91.4%, 56.5% and 27.9% for metastatic disease, respectively.
CONCLUSION
SRFA represents a viable alternative to hepatic resection for challenging tumors at the hepatic venous confluence.
Topics: Carcinoma, Hepatocellular; Catheter Ablation; Humans; Liver Neoplasms; Neoplasm Recurrence, Local; Radiofrequency Ablation; Retrospective Studies; Treatment Outcome
PubMed: 34887174
DOI: 10.1016/j.hpb.2021.11.010