Ablation Efficiency Research Articles

Comparison of Therapeutic Effects Between Pulsed Field Ablation and Cryoballoon Ablation in the Treatment of Atrial Fibrillation: A Systematic Review and Meta-analysis

Pulsed field ablation (PFA) is a novel nonthermal ablation technique for the treatment of atrial fibrillation (AF) patients, with safety comparable to traditional catheter ablation surgery. The present study aims to evaluate and compare the procedural efficiency and safety profiles of PFA and cryoballoon ablation (CBA) in the management of AF. We performed a systematic search across PubMed, the Cochrane Library, and Embase databases, encompassing the literature up to February 2024, to inform our systematic review and meta-analysis. When assessing outcome indicators, the risk ratio and its corresponding 95% confidence interval (CI) were calculated for dichotomous variables. For continuous variables, the mean difference (MD) and the associated 95% CI were determined. In this scenario, a relative risk (RR) value of less than 1 and an MD value of less than 0 are deemed favorable for the PFA group. This could translate to a reduced likelihood of procedural complications or enhanced procedural performance within the PFA group. In this analysis, 9 observational studies encompassing 2875 patients with AF were included. Among these, 38% (n = 1105) were treated with PFA, while 62% (n = 1770) received CBA. The results indicated that PFA was associated with a significantly shorter procedural duration compared with CBA, with an MD of −10.49 minutes (95% CI, −15.50 to −5.49; P < 0.0001). Nevertheless, no statistically significant differences were observed when comparing the 2 treatment cohorts concerning fluoroscopy time (MD, 0.71; 95% CI, −0.45 to 1.86; P = 0.23) and the recurrence of atrial arrhythmias during follow-up (RR, 0.95; 95% CI, 0.78–1.14; P = 0.57). In terms of perioperative complications, the PFA group showed a significantly decreased risk of phrenic nerve palsy (RR, 0.15; 95% CI, 0.06–0.39; P < 0.0001) and an increased risk of cardiac tamponade (RR, 3.48; 95% CI, 1.26–9.66; P = 0.02) compared with the CBA group. No significant differences were noted between the PFA and CBA groups regarding the incidence of stroke/transient ischemic attack (RR, 0.99; 95% CI, 0.30–3.22; P = 0.99), vascular access complication (RR, 0.87; 95% CI, 0.36–2.10; P = 0.76), atrial esophageal fistula (RR, 0.33; 95% CI, 0.01–8.13; P = 0.50), and major or minor bleeding events (RR, 0.39; 95% CI, 0.09–1.74; P = 0.22). Our research results indicate that compared with CBA, PFA not only shortens the procedure time but also demonstrates noninferiority in terms of fluoroscopy duration and the recurrence rate of atrial arrhythmias. PFA and CBA have both demonstrated their respective advantages in perioperative complications.

Vapor Channel Oscillations in Laser Lithotripsy.

Laser-based endoscopic procedures present special challenges to deliver energy for ablation or coagulation of target tissues. When optical fiber-target quasi-contact (< 0.5 mm distance) cannot be maintained or is undesirable, the creation of intervening vapor bubbles and channels provide for the necessary transmission of laser energy to the target. This work investigates the characteristics and the dynamics of vapor channels that directly affect ablation efficiency and ablation rate and are known to effect stone movement, all of which impact procedure efficiency and safety. A simplified, experimental model for thulium fiber laser (1940 nm) lithotripsy consists of a water-filled cuvette and a vertically oriented laser fiber (200 μm core diameter) with its tip at 9 mm for "quasi-free" bubble generation and at vapor channel working distances 1-5 mm from and centered on the transparent cuvette bottom simulating a target's surface. Laser power transmission is recorded and synchronized with video frames from a high-speed camera (24,260 frames per second) to capture the induced vapor channels' and bubbles' development. Laser-induced channel transmission from 0% to 100% for 1, 2, and 3 mm fiber-target distances undergoes oscillations with average periods of 0.32, 0.64, and 1.0 ms, respectively, for 500 W laser output power. For fixed fiber-target distances of 0.5, 1, and 2 mm, the variation of these average oscillation frequencies across laser powers from 500 to 1000 W is much smaller, not exceeding 14%. For fiber-target distances in the range of 1-5 mm, the fraction of the 500 W laser's total pulse energy delivered to the target for 1, 2, and 3 ms pulses linearly decreases from 0.78 to less than 0.2. The channel and bubble dynamics begin with a spherical seed bubble expansion centered on the distal fiber tip that evolves into a pear shape whose surface exhibits periodic irregularities attributable to laser beam interruption by water droplets within the developing bubble. The study of laser-induced channel oscillations provides quantitative information relating fiber-target distance to channel oscillation frequency and energy transmission onto a target. These oscillations directly effect ablation efficiency and ablation rates that are important parameters for the optimization of a procedure's safety and duration. Insights that may lead to further reduction in retropulsion are also presented. Lasers Surg. Med. 00:00-00, 2024. © 2024 Wiley Periodicals LLC.

Design of dinuclear osmium complex doped antifouling cellulose nanoparticles for targeting and dual photodynamic/photothermal therapy under near infrared irradiation

Transition metal-ligand has been explored in the treatment of tumors in photodynamic theray (PDT) or photothermal therapy (PTT) and Osmium complex attracts attentration due to its lower toxicity and longer absorption wavelength. However, there was no report about binuclear Os complex for combined therapy of PDT and PTT which could have a synergistic effect and improve the effectiveness. Herein, we synthesis of mono/dinuclear Os complexes (OsY1, OsY2) with dual PDT/PTT capabilities under a single near-infrared (NIR) excitation wavelength. These features arise from the large π-conjugated structure of our dinuclear Os complex coupled with efficient metal-to-ligand charge transfer, which bring in ultralow energy gaps of 0.733 eV and 0.308 eV for OsY1 and OsY2, respectively. Furthermore, we prepared the Osmium complex-doped, aptamer-conjugated cellulose NPs via the emulsion polymerization method. These NPs exhibit a notable ability to target mitochondria and posse a “protein corona-free” status, showing much higher efficiency in tumor ablation (76 %) than the commercialized indocyanine green (ICG) doped cellulose NPs (24 %) under 808 nm irradiation. Consequently, our designed mono/dinuclear Os complex, featuring a single-molecule dual PDT/PTT effect within doped antifouling NPs, holds promise for potential applications in cancer therapy.

Advanced mapping and ablation technologies to target pulmonary veins gaps and residual antral potentials during repeat paroxysmal AF ablation: acute and long-term follow-up

Abstract Background A comprehensive understanding of pulmonary vein (PV) reconnection and residual potentials (RAP) within the antral scar during repeat atrial fibrillation (AF) ablation, facilitated by advanced mapping and ablation technologies, is currently lacking. Optimizing radiofrequency (RF) deliveries after failed PV isolation (PVI) may enhance ablation efficiency. Purpose This study aims to assess both the acute and long-term outcomes focusing on PV gaps (PVGs) and RAPs, utilizing advanced mapping and ablation technologies during repeat PV ablation in patients (pts) with paroxysmal AF. Methods Repeat AF-CHARISMA study, a prospective, single-arm cohort study, included consecutive pts from 13 centers undergoing repeat ablation of paroxysmal AF. The Lumipoint (Boston Scientific) map-analysis tool was used sequentially on each PV component. All patients were followed-up for at least 12 months after the procedure. The ablation endpoint was PVI and electrical quiescence in the antral region. Long-term outcome was the recurrence of AT/AF over follow-up. Results One-hundred pts were included (69% after failed RF procedure, 31% after failed cryoablation procedure). A total of 276 PVGs (192 after RF ablation, 2.8±1.8/pt; 84 after cryoablation, 2.7±1.9/pt, p=0.665 vs RF) and 44 RAPs (43 after RF ablation, 0.6±1.1/pt; 1 after cryoablation, 0.03±0.2/pt, p=0.002 vs RF) were detected. In the majority of cases (75%), only PVGs were present whereas, in 21%, both PVGs and RAPs were detected (2 pts had only RAPs). In 2 pts no PVG nor RAP were identified. PVGs were most common at anterior sites (103, 37.3%), followed by posterior sites (75, 27.2%) and carina sites (49, 17.8%). PVG location sites did not differ between prior ablation approach. Only 1 pt after cryoablation showed a RAP (at carina site), whereas the 44 RAPs after RF were fairly distributed across different sites. Acute procedural success was 100%, with all PVs successfully isolated and RAPs completely abolished in all study pts. After the blanking period, over a follow-up of 480±211 days, 18 pts (18%) suffered an AT/AF recurrence (time to recurrence: 245±80 days). Previous ablation approach (HR=0.66, 95%CI: 0.2 to 2.0 for previous cryoablation, p=0.46), number of PVGs (1.05, 0.8 to 1.3, p=0.67) or number of RAPs (0.41, 0.1 to 1.2, p=0.12) were not associated to AT/AF recurrence. No major complications or adverse events occurred. Conclusion A structured ablation workflow for repeat catheter ablation, incorporating consistent high-density mapping and improved diagnostic tools to guide the procedure, demonstrated safety and efficacy in treating paroxysmal AF irrespectively of previous ablation approach. Residual potentials within the antral scar were more frequently detected after RF ablation compared to cryoablation.

Passively Mode-Locked Erbium-Doped Fiber Laser and Application in Laser Thrombolysis

Fiber lasers have been widely used in surgery with the development of fiber photonics. Since the human body is prone to myocardial infarction caused by blood clots, laser thrombolysis was proposed as a safe and efficient treatment. Mode-locked fiber lasers have high peak power and narrow pulse width. In order to observe the effect of laser thrombolysis with mode-locked fiber lasers, a 1.5 µm mode-locked fiber laser based on carbon nanotubes was built, showing a pulse width of 1.46 ps, a 3 dB bandwidth of 1.65 nm, and a repetition rate of 29.5 MHz. The output pulses were amplified by an erbium-doped fiber amplifier to the hundred-milliwatt level and were applied to the surface of a self-made thrombus. The influences of lasing power and time on the damage diameter of the thrombus surface were evaluated. A low threshold damage power of 45 mW was observed, which resulted from the high peak power of the mode-locked pulses. These results demonstrate that high ablation efficiency can be achieved by using mode-locked pulses with a narrow pulse width and high peak power.

Review of high-precision femtosecond laser materials processing for fabricating microstructures: Effects of laser parameters on processing quality, ablation efficiency, and microhole shape

Femtosecond lasers are promising tools for achieving high-precision processing of thin materials without causing any thermal surface damage and bulk distortion. However, thermal damage can occur even with ultrashort laser pulses. This is because of high electron penetration depth and heat accumulation at high fluence and high repetition rate. Nanoparticle redeposition can be dramatically altered with variation in repetition rate. The symmetry of microholes and ablation efficiency vary with laser polarization. The laser wavelength affects the ablation efficiency and surface roughness. Therefore, understanding these laser–matter interactions that depend on the laser parameters is essential for high-precision laser processing. This article reviews laser–matter interactions in the 64FeNi alloy, as well as analytical models for designing the desired hole size and taper angles. This can help establish strategies for creating various high-precision microstructures using femtosecond lasers.

Multi-stage automatic and rapid ablation and needle trajectory planning method for CT-guided percutaneous liver tumor ablation.

Computer-assisted planning methods have increasingly contributed to preoperative ablation planning; however, these methods cannot automatically obtain the final optimal solution within a short time and are rarely validated in practice, greatly limiting their clinical applicability. We aimed to propose a full-automatic multi-stage ablation and needle trajectory planning method for CT-guided percutaneous liver ablation to attain the final optimal plans under multiple clinical constraints rapidly. Our proposed method integrates the ablation zone planning fulfilling complete tumor coverage and critical structure avoidance while reaching a trade-off between ablation number and healthy tissue damage, and needle trajectory planning under multiple clinical constraints. Our needle trajectory planning determines feasible skin entry regions based on hard constraints, where the multi-objective optimization (MOO) considering soft constraints is performed using the Pareto Optimality and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) methods for the final optimal solution. The performance of our proposed method was evaluated on 30 tumors of various characteristics from 23 patients and clinically validated in five clinical cases. Our proposed method achieved 99.8% treatment zone coverage and 40.5% ablation efficiency without involving critical structures, and completely satisfied multiple clinical constraints in all needle trajectory planning results. The average planning time was 23.6 s for tumors of different sizes. All the plans were considered clinically acceptable by the doctors' evaluation. Our method achieved complete tumor coverage without complications in clinical case validation. Our proposed planning method can generate a final optimal plan satisfying multiple clinical constraints within a short time, potentially facilitating preoperative planning for hepatic tumor ablation.

Pulse Duration Dependent Formation of Laser‐Induced Periodic Surface Structures in Atomic Layer Deposited MoS2

AbstractIn this paper, the formation of laser‐induced periodic surface structures (LIPSS) on atomic‐layer deposited MoS2 layers are studied experimentally. The process parameters (laser fluence and the pulse overlap) corresponding to formation of low‐ and high‐spatial frequency LIPSS as well as ablation and modification of the layers are identified for different pulse durations in the range from 0.2 to 10 ps. The role of the temperature accumulation is evaluated by changing the repetition rate from 0.2 to 2 MHz. The negative accumulation effect, i.e., the ablation of the layers becomes more difficult at higher laser pulse overlaps, is also observed. A simple model explaining the transition between different types of the LIPSS and the decrease of the ablation efficiency with the pulse overlap is suggested.

Ablation efficiency and laser safety of a novel superpulsed thulium fiber laser: a in vitro study.

To assess the ablation efficiency of the Superpulsed Thulium Fiber Laser (SP-TFL) and investigate the thermal effects of SP-TFL. A SP-TFLwas employed to evaluate ablation efficiency. Fresh ex-vivo pig kidneys and ureters were utilized to evaluate the renal pelvis and ureter temperature changes, different irrigation rates(0, 15, 38mL/min) and a long pulse width were used. The research indicated that as laser output power increased, ablation rates significantly increased. Ablation rates(mg/min) were higher and the energy per ablated mass(J/mg) was lower at lower frequencies(10-50Hz). Under the same frequency and single pulse energy, super short and short pulse widths demonstrated higher ablation rates at higher frequencies (exceeding 100Hz). The temperature of the renal pelvis and ureter decreased with increasing irrigation rates. In the renal pelvis, without irrigation, the temperature quickly reached the critical threshold of 43℃. The irrigation rate was 15ml/min and power was no more than 18W, the renal pelvis temperature did not reach 43℃. When the irrigation rate were 38ml/min, the temperature did not risen to 43℃. In the ureter, without irrigation, the temperature also quickly reached 43℃. The temperature reached 43℃ when the power exceeded to12W with an irrigation rate of 15ml/min. With an irrigation rate of 38ml/min, the temperature reached 43℃ at a laser power of 30W. The SP-TFL demonstrated promising ablation effectiveness especially for lower frequencies and super short and short pulse widths model. Proper irrigation rates, single pulse energy, frequency and pulse width are crucial during lithotripsy.

Optical-Propulsion Metastructures.

Pulsed laser micropropulsion (PLMP) offers a promising avenue for miniature space craft, yet conventional propellants face challenges in balancing efficiency and stability. An optical-propulsion metastructure strategy using metal-organic frameworks (MOFs) is presented to generate graphene-metal metastructures (GMM), specifically GMM-(HKUST-1), which significantly enhances PLMP performance. This novel approach leverages the unique interaction between pulsed lasers and the precisely engineered GMMs-comprising optimized metal nanoparticle size, graphene layers, and inter-particle gaps-to boost both propulsion efficiency and stability. Experimental and numerical analyses reveal that GMM-(HKUST-1) achieves aspecific impulse of 1072.94 s, ablation efficiency of 51.22%, and impulse thrust per mass of 105.15 µN µg-1, surpassing traditional propellants. With an average particle size of ≈12 nm and a density of 0.958gcm-3, these metastructures exhibit 99% light absorption efficiency and maintain stability under atmospheric and humid conditions. The graphene nanolayer efficiently absorbs and converts laser energy, while the metal nanostructures enhance light-matter interactions, promoting energy transfer and material stability. These findings suggest that this GMM-based optical-propulsion strategy can revolutionize microspacecraft propulsion and energy systems, offering significant advancements across various domains.

Comparison of material removal efficiency in laser ablation of polycrystalline diamond for different pulse durations

The study experimentally investigates the effect of three different pulse durations on the laser ablation of polycrystalline diamond (PCD), focusing on ablation depth and the morphology of the ablated craters. The results indicate that as the number of incident pulses (N.P) increases, the ablation depth per pulse reaches a constant value. A considerable difference in ablation depth, by nearly a factor of two, was observed for the 16 ns pulses compared to 12 ps and 250 fs pulses. In addition to the single-point experiment, three volume ablation tests with these pulse durations were performed. The results show that the material removal rates for the ns, fs, and ps lasers are the highest, respectively. Additionally, the ablation efficiency in volume ablation process was compared with single-point process, indicating considerable inconsistency in removal depth for ns and ps lasers.

Study of burst mode for enhancing the ps-laser cutting performance of lithium-ion battery electrodes

The demand for lithium-ion batteries (LIBs) has increased significantly, leading to an increased focus on high quality production methods. In response to this growing demand, laser technology has been increasingly used for electrode notching and cutting. In addition, the advent of high-power ultrashort lasers equipped with burst mode capabilities represents a promising option for electrode cutting of LIBs. On the other hand, these types of lasers for this purpose are relatively unexplored in the literature. This study investigates the effect of various parameters, including the number of pulses per burst (ranging from 1 to 8), the pulse repetition rate (200.0, 550.3, and 901.0 kHz), and the burst shape (equal pulse peak and increasing pulse peak), on the laser cutting process of aluminum foil, cathode, copper foil, and anode. The results indicate that increasing the number of pulses per burst and the pulse repetition rate improves productivity and quality for all materials, with a more significant effect observed for metal foil than for cathode and anode materials due to the different laser-material interactions for metal foil and active material. The burst shape with equal pulse peaks was found to be a more suitable temporal distribution for cutting all materials compared to an increasing pulse peak distribution. The ablation efficiency was evaluated as a function of the peak fluence of a single pulse within the burst. The results emphasize that higher productivity at higher average power can be achieved by increasing the pulse repetition rate toward the MHz range with moderate pulse energies.

High efficiency femtosecond laser ablation of alumina ceramics under the filament induced plasma shock wave

Femtosecond laser filament enables energy transfer over long distances, which is of great value for studying long-range ablation. However, the energy coupling of filament with the plasma generated by the ablation process leads to a very complex behavior which limits the ablation efficiency. This study systematically investigated the ablation mechanism of laser-induced filament in alumina ceramic. The plasma shock wave was initially investigated using spectral detection techniques combined with Sedov-Taylor theory. The results indicated that the maximum plasma shock wave reached 30 MPa under the irradiated by a 1 mJ fs laser. The theoretical analysis confirmed the effectiveness of the filament-induced plasma shock wave in enhancing the ablation rate of alumina ceramic. In this context, the experimental studies were conducted with varying filament positions and pulse energies, and the corresponding ablation rates for each parameter were investigated. The filament in the ablation process was found to has a secondary sputtering effect, which is an effective contributor to enhance the ablation rate. The corresponding ablation depth reach to 550 μm while achieving an ablation rate of 3.1 μm3/μJ. Finally, the coupling mechanism between the femtosecond laser filament and the plasma shock wave was systematically revealed. This research will facilitate future laser remote ablation applications with high efficiency.

Clinical Efficiency and Safety of Radiofrequency Ablation for Treating Incompetent Great Saphenous Veins in Aged Patients.

Few studies have focused on the safety and efficacy of radiofrequency ablation (RFA) in treating incompetent great saphenous vein (GSV) in aged population. This study was designed to investigate the clinical efficacy of RFA in treating incompetent GSV in the aged patients. In this retrospective study, we included 138 consecutive patients (involving 194 limbs) with a mean age of 63.0 years who underwent RFA and microphlebectomy or sclerotherapy due to symptomatic incompetent GSV with saphenofemoral junction reflux. Based on their ages, patients were classified into young group and aged group. Then we compared the preoperative and postoperative Clinical, Etiology, Anatomic, Pathophysiology (CEAP) classification, venous clinical severity score (VCSS) and chronic venous insufficiency questionnaire 14 (CIVIQ-14) score between the 2 groups. In both the young and aged groups, patients underwent RFA showed significant decrease in the CEAP and VCSS at month 1, 3 and 6 compared with immediately after RFA (month 0) (all P < .001). In addition, in both groups, significant increase was seen in the CIVIQ-14 score at month 1, 3 and 6 compared with month 0 (all P < .001). Compared with the young group, the post-RFA CEAP, VCSS and CIVIQ-14 scores showed no statistical differences in the aged group at the designated time points, respectively (all P > .05). RFA of GSV was effective for treating GSV in the aged population, which improved the CEAP, VCSS and CIVIQ-14.

Initial Clinical Experience With a Novel Robotically Assisted Platform for Combined Mini-Percutaneous Nephrolithotomy and Flexible Ureteroscopic Lithotripsy.

We sought to evaluate the technical feasibility of performing a combined robotically assisted mini-percutaneous nephrolithotomy (PCNL) and flexible ureteroscopy (URS) procedure by a single urologist using the MONARCH Platform, Urology (Johnson & Johnson MedTech, Redwood City, California). In this prospective, first-in-human clinical trial, 13 patients underwent robotically-assisted PCNL for renal calculi at the University of California-Irvine, Department of Urology. Successful completion of the procedure was assessed as the primary endpoint. Postoperative adverse events were monitored for 30 days following the completion of the procedure. Stone ablation efficiency was evaluated on postoperative day 30 with low-dose 2-3 mm slice CT scans. Patients were classified according to the maximum length of their residual stone fragments as either absolute stone-free (Grade A), < 2 mm remnants (Grade B), or 2.1-4.0 mm remnants (Grade C). The combined robotic mini-PCNL and URS procedure was successfully completed in 12 of 13 procedures. No robotic device-related adverse events occurred. Preoperative stone burden was quantified by both maximum linear measurement (median 32.8 mm) as well as by CT-based volume (median 1645.9 mm3). Using the unique robotically assisted targeting system, percutaneous access was gained directly through the center of the renal papilla in a single pass in all cases. Median operative time was 187 minutes (range: 83-383 minutes). On postoperative day 30, a 98.7% (range: 72.9%-100.0%) volume reduction was achieved, with 5 Grade A (38.5%), 1 Grade B (7.7%), and 2 Grade C (15.4%). Three patients experienced complications (2 grade 1 and one grade 2 Clavien-Dindo). Our preliminary investigation demonstrates the safety, efficacy, and feasibility of a unique robotic-assisted combined mini-PCNL and URS platform.

Microstructuring of fused silica by laser-induced microplasma using a pyrographite target for phase optical elements fabrication

In this paper, we purpose to use laser-induced microplasma occurred from a pyrographite target by laser ablation for microstruturing of fused silica plate to fabricate phase optical elements. Laser parameters for erosive plasma torch formation and subsequent etching of fused silica were determined based on preliminary experimental studies and estimated energy calculations. The influence of the overlap coefficients in the focal spot on the reproducibility of etching depths results and the deviation accuracy of etching depths with the found laser parameters was experimentally studied. The best results in terms of accuracy (no more than 0.1 μm) in deviations of etching depths are achieved with the overlap coefficient of 0.5. Moreover, the paper presents estimated calculations of the speed and efficiency of ablation, as well as the coefficient of energy conversion from laser radiation to the ablation energy of fused silica, which was ∼ 0.25. Based on achieved results an attempt was made to fabricate the 6-sector SPP for the wavelength of 355 nm.

Clinical efficiency and safety of high-power short-duration radiofrequency ablation in treatment of patients with atrial fibrillation

Clinical efficiency and safety of high-power short-duration radiofrequency ablation in treatment of patients with atrial fibrillation

Computer simulation of low-power and long-duration bipolar radiofrequency ablation under various baseline impedances

Compared to traditional unipolar radiofrequency ablation (RFA), bipolar RFA offers advantages such as more precise heat transfer and higher ablation efficiency. Clinically, myocardial baseline impedance (BI) is one of the important factors affecting the effectiveness of ablation. We aim at finding suitable ablation protocols and coping strategies by analyzing the ablation effects and myocardial impedance changes of bipolar RFA under different BIs. In this research, a three-dimensional local myocardial computer model was constructed for bipolar RFA simulation, and in vitro experimental data were used to validate accuracy. Four fixed low-power levels (20 W, 25 W, 30 W, and 35 W) and six myocardial BIs (91.02 Ω, 99.83 Ω, 111.03 Ω, 119.77 Ω, 130.03 Ω, and 135.45 Ω) were set as initial conditions, with an ablation duration of 120-s. In the context of low-power and long-duration (LPLD) ablation, the maximum TID (TIDM) decreased by 21–32 Ω, depending on the BI. In cases where steam pop did not occur, TIDM increased with the increase in power. For the same power, there was no significant difference in TIDM for the range of BIs. In cases where steam pop occurred, for every 1 Ω increase in BI, TIDM increased by 0.34–0.41 Ω. The simulation results also showed that using a higher power resulted in a smaller decrease in TIDM. This study provided appropriate ablation times and impedance decrease ranges for bipolar LPLD RFA. The combination of 25 W for 120-s offered optimal performance when considering effectiveness and safety simultaneously.

General Anesthesia Improves Efficiency of High-Power Short-Duration Catheter Ablation for Atrial Fibrillation: Comparison with Mild Conscious Sedation.

Atrial fibrillation (AF) is the most common cardiac arrhythmia globally. High-power, short-duration radiofrequency (RF) catheter ablation (CA) for AF has recently emerged, reducing ablation times and enhancing patient tolerability with comparable efficacy and safety. While the benefits of general anesthesia (GA) for standard-power, standard-duration CA are well-established, data comparing GA to mild conscious sedation (MCS) for high-power, short-duration CA are limited. We included patients undergoing high-power, short-duration CA for AF under GA (group 1) or MCS (group 2). Procedural characteristics, success rates, and mid-term outcomes were compared. In total, 131 patients, 47 in the GA group and 84 in the MCS group, were included. CA was performed for paroxysmal AF in 34 patients in group 1 (72.3%) and 68 patients in group 2 (80.9%). We found lower a mean total procedure time (100 [90-120] vs. 160 [130-180] min, p < 0.0001), lower radiation exposure (932.5 [625-1716] vs. 2445 [1228-4791] μGy, p < 0.0001 and 4.5 [3-7.1] 7.3 [4.2-13.5] min, p = 0.0003) and fewer RF applications (71 [54.8-83.8] vs. 103 [88.5-120.5], p < 0.0001) in the GA group. No major complications occurred. The 6-month AF recurrence rate was comparable between the groups (21.2% vs. 33.3%, p = 0.15). In patients undergoing high-power, short-duration RFCA for AF, the use of GA is associated with better procedural efficiency while simultaneously associated with an early recurrence rate comparable to MCS.

Treatment of Urolithiasis with Thulium Fiber Laser in Fragmentation Mode Using Optimized Pulse Sequences.

Objectives: The super-pulsed thulium fiber laser (SP TFL) is a new alternative to high-power holmium laser for intracorporeal lithotripsy. The SP TFL has shown advantages in dusting regimes, but benefits in fragmentation regimes are less understood. The second-generation SP TFL introduces an advanced fragmentation pulse (AFP) sequence to maximize SP TFL's efficiency in fragmentation. This study evaluates safety and efficacy of the SP TFL fragmentation mode in ureteroscopy (URS) and mini percutaneous nephrolithotomy (mini-PCNL). Materials and Methods: The study was conducted in two phases. Safety of a new AFP was compared ex vivo to standard SP TFL fragmentation settings by measuring the dimensions of wounds created in porcine kidney after laser exposure for 0.5, 1.0, and 2.0 s. The resulting wounds were evaluated histologically using nitro blue tetrazolium chloride (NBTC) stain. In the clinical phase, the second-generation SP TFL was used to fragment and extract ureteral and renal stones in 40 patients using ureteroscopic and percutaneous approaches. The stone size, volume, density, laser-on-time, and total energy were recorded for each patient. In addition, the chemical composition, ablation rate, and ablation efficiency were assessed for each stone treatment. Results: The ex vivo mucosa damage profiles caused by AFP were similar to those caused by regular pulses. In clinical phase, the median volume and density for ureteral stones were 0.4 cm3 and 1029 Hounsfield units (HU), for renal stones 1.3 cm3 and 1113 HU, respectively. Different stone types were crushed into fragments suitable for extraction. The mean AFP energy was 3 J and the average power for ureteral stones was 10.5 W, whereas for renal stones it was 28.5 J and 31 W, respectively. The overall complication rate was low in both groups. Conclusion: ST PFL with AFP capability facilitates effective fragmentation of ureteral and renal stones of any composition during URS and mini-PCNL with minimal complication rates.