Sensor-Based Measurement Method to Support the Assessment of Robot-Assisted Radiofrequency Ablation.

Digital surgery technologies, such as interventional robotics and sensor systems, not only improve patient care but also aid in the development and optimization of traditional invasive treatments and methods. Atrial Fibrillation (AF) is the most common cardiac arrhythmia with critical clinical relevance today. Delayed intervention can lead to heart failure, stroke, or sudden cardiac death. Although many advances have been made in the field of radiofrequency (RF) catheter ablation (CA), it can be further developed by incorporating sensor technology to improve its efficacy and safety. Automation can be utilized to shorten the duration of RF ablation, provided that the interactions between the tissue and the RF tools are well understood and adequately modeled. Further research is needed to develop the optimal catheter design. This paper describes the systematic methodology developed to support robot-assisted RF CA characterization measurements. The article describes the custom instruments developed for the experiments, particularly the contact force limiter, the measurement procedure, and the evaluation of the results, as enablers for new results. The aim was to establish an objective, repeatable, robust measurement method and adjacent procedure.

Catheter ablation for supraventricular tachycardia and health resource utilization and expenditures: A propensity-matched cohort study.

BACKGROUND: Few data are available regarding temporal patterns of health resource utilization (HRU) and expenditures among patients undergoing catheter ablation for paroxysmal supraventricular tachycardia (PSVT). This study aimed to describe expenditures and HRU in patients with PSVT who underwent catheter ablation compared to a matched cohort of patients on medical therapy alone. METHODS: Using a large US administrative database, we identified adult patients (age 18 to 65 years) with a new PSVT diagnosis between 2008 and 2016. Propensity-score matching was used to assemble a PSVT cohort treated with ablation or medical therapy alone (N = 2556). Longitudinal trends in HRU and expenditures in the 3-years preceding and following PSVT diagnosis were compared. RESULTS: There were no significant differences in expenditures between groups except within the first year after PSVT diagnosis: $48,004 ablation vs. $17,560 medical therapy (p < 0.001). This difference was driven by procedural expenditures, where the mean cost of catheter ablation was $32,057 ± SD 26,737. In Years 2 and 3 post-ablation, HRU and expenditures decreased to the levels associated with the medical therapy group, although fewer ablation patients required any prescription for beta-blockers, calcium channel blockers, or anti-arrhythmic drugs (32% ablation vs. 42% medical therapy group, p < 0.001). CONCLUSION: Catheter ablation reduces medication burden in PSVT, yet health resource use and expenditures were similar beyond 2 years post-ablation when compared to PSVT patients on medical therapy alone. Additional studies are required to better understand drivers of these sustained health expenditures, and barriers to achieving cost-savings for a potentially curative procedure.

Cost-utility of VISITAG SURPOINT in catheter ablation of atrial fibrillation.

BACKGROUND: Clinical studies have demonstrated the safety, efficacy, and efficiency of VISITAG SURPOINT® (VS), which provides important lesion markers during catheter ablation (CA) of atrial fibrillation (AF). The present study evaluated the cost-effectiveness of CA with VS compared to CA without VS in AF from the publicly-funded German and Belgium healthcare perspectives. METHODS: We constructed a two-stage cost utility model that included a decision tree to simulate clinical events, costs, and utilities during the first year after the index procedure and a Markov model to simulate transitions between health states throughout a patient's lifetime. Model inputs included published literature, a meta-analysis of randomized controlled trials AF outcomes, and publicly available administrative data on costs. Deterministic and probabilistic sensitivity analyses were conducted to determine the robustness of the model. RESULTS: CA with VS was associated with lower per patient costs vs CA without VS (Germany: €3295 vs. €3936, Belgium: €3194 vs. €3814) and similar quality-adjusted life-years (QALYs) per patient (Germany: 5.35 vs. 5.34, Belgium: 5.68 vs. 5.67). CA with VS was the dominant ablation strategy (incremental cost-effectiveness ratios: Germany: €-52,455/QALY, Belgium: €-50,676/QALY). The model results were robust and not highly sensitive to variation to individual parameters with regard to QALYs or costs. Freedom from AF and procedure time had the greatest impact on model results, highlighting the importance of these outcomes in ablation. CONCLUSIONS: CA with VS resulted in cost savings and QALY gains compared to CA without VS, supporting the increased adoption of VS in CA in Germany and Belgium.

Directional microwave ablation in spine: experimental assessment of computational modeling.

BACKGROUND: Despite the theoretical advantages of treating metastatic bone disease with microwave ablation (MWA), there are few reports characterizing microwave absorption and bioheat transfer in bone. This report describes a computational modeling-based approach to simulate directional microwave ablation (dMWA) in spine, supported by ex vivo and pilot in vivo experiments in porcine vertebral bodies. MATERIALS AND METHODS: A 3D computational model of microwave ablation within porcine vertebral bodies was developed. Ex vivo porcine vertebra experiments using a dMWA applicator measured temperatures approximately 10.1 mm radially from the applicator in the direction of MW radiation (T1) and approximately 2.4 mm in the contra-lateral direction (T2). Histologic assessment of ablated ex vivo tissue was conducted and experimental results compared to simulations. Pilot in vivo experiments in porcine vertebral bodies assessed ablation zones histologically and with CT and MRI. RESULTS: Experimental T1 and T2 temperatures were within 3-7% and 11-33% of simulated temperature values. Visible ablation zones, as indicated by grayed tissue, were smaller than those typical in other soft tissues. Posthumous MRI images of in vivo ablations showed hyperintensity. In vivo experiments illustrated the technical feasibility of creating directional microwave ablation zones in porcine vertebral body. CONCLUSION: Computational models and experimental studies illustrate the feasibility of controlled dMWA in bone tissue.

Three-Dimensional Margin as a Predictor of Local Tumor Progression after Microwave Ablation: Intraprocedural versus 4-8-Week Postablation Assessment.

PURPOSE: To evaluate the prognostic accuracy of intraprocedural and 4-8-week (current standard) post-microwave ablation zone (AZ) and margin assessments for prediction of local tumor progression (LTP) using 3-dimensional (3D) software. MATERIALS AND METHODS: Data regarding 100 colorectal liver metastases (CLMs) in 75 patients were collected from 2 prospective fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT)-guided microwave ablation (MWA) trials. The target CLMs and theoretical 5- and 10-mm margins were segmented and registered intraprocedurally and at 4-8 weeks after MWA contrast-enhanced CT (or magnetic resonance [MR] imaging) using the same methodology and 3D software. Tumor and 5- and 10-mm minimal margin (MM) volumes not covered by the AZ were defined as volumes of insufficient coverage (VICs). The intraprocedural and 4-8-week post-MWA VICs were compared as predictors of LTP using receiver operating characteristic curve analysis. RESULTS: The median follow-up time was 19.6 months (interquartile range, 7.97-36.5 months). VICs for 5- and 10-mm MMs were predictive of LTP at both time assessments. The highest accuracy for the prediction of LTP was documented with the intra-ablation 5-mm VIC (area under the curve [AUC], 0.78; 95% confidence interval, 0.66-0.89). LTP for a VIC of 6-10-mm margin category was 11.4% compared with 4.3% for >10-mm margin category (P < .001). CONCLUSIONS: A 3D 5-mm MM is a critical endpoint of thermal ablation, whereas optimal local tumor control is noted with a 10-mm MM. Higher AUCs for prediction of LTP were achieved for intraprocedural evaluation than for the 4-8-week postablation 3D evaluation of the AZ.

Radiofrequency ablation using the ThermoCool SmartTouch Catheter guided by ablation index versus antiarrhythmic drugs in atrial fibrillation treatment in China: a cost-consequence analysis.

Aim: To evaluate the costs and consequences of two front-line atrial fibrillation (AF) treatments from Chinese healthcare system perspective: radiofrequency catheter ablation (RFCA) using ThermoCool SmartTouch Catheter guided by Ablation Index (STAI), in comparison to antiarrhythmic drugs (AADs). Patients & methods: We simulated clinical and economic consequences for AF patients initially receiving STAI or AADs using a short-term decision tree model leading to a 10-year long-term Markov model. The model projected both clinical consequences and costs associated with, among others, AF, heart failure (HF), strokes, and deaths due to AF or AF related complications. Data informing the models included combination of a local real-world study and published clinical studies. Results: STAI was advantageous versus AADs on all 4 main clinical outcomes evaluated; AF: 25.83% lower (12.84% vs 38.67%), HF: 2.22% lower (1.33% vs 3.55%), stroke or post stroke: 1.82% lower (10.00% vs 11.82%) and deaths due to AF or AF related complications: 0.64% lower (4.11% vs 4.75%). The average total cost per patient in STAI group was ¥16,682 lower (¥123,124 vs ¥139,806). The one-way sensitivity analysis indicated that the difference in total cost was most sensitive to annual AF recurrence probability in AADs-treated patients. Probabilistic sensitivity analysis indicated a 98.5% probability that RFCA treatment would result in cost savings by the end of the 10th year. Conclusion: Radiofrequency catheter ablation using SmartTouch catheter guided by Ablation Index was superior to AADs as the first-line AF treatment in Chinese setting with better clinical outcomes and at lower costs over a 10-year time horizon.

MRI non-rigid registration with tumor contraction correction for ablative margin assessment after microwave ablation of hepatocellular carcinomas.

Objective. This study aims to develop and assess a tumor contraction model, enhancing the precision of ablative margin (AM) evaluation after microwave ablation (MWA) treatment for hepatocellular carcinomas (HCCs).Approach. We utilize a probabilistic method called the coherent point drift algorithm to align pre-and post-ablation MRI images. Subsequently, a nonlinear regression method quantifies local tumor contraction induced by MWA, utilizing data from 47 HCC with viable ablated tumors in post-ablation MRI. After automatic non-rigid registration, correction for tumor contraction involves contracting the 3D contour of the warped tumor towards its center in all orientations.Main results. We evaluate the performance of our proposed method on 30 HCC patients who underwent MWA. The Dice similarity coefficient between the post-ablation liver and the warped pre-ablation livers is found to be 0.95 ± 0.01, with a mean corresponding distance between the corresponding landmarks measured at 3.25 ± 0.62 mm. Additionally, we conduct a comparative analysis of clinical outcomes assessed through MRI over a 3 month follow-up period, noting that the AM, as evaluated by our proposed method, accurately detects residual tumor after MWA.Significance. Our proposed method showcases a high level of accuracy in MRI liver registration and AM assessment following ablation treatment. It introduces a potentially approach for predicting incomplete ablations and gauging treatment success.

A Comparison of Venaseal Versus Radiofrequency Ablation Outcomes Within a Managed Care Organization.

BACKGROUND: Chronic venous insufficiency is a common medical condition that afflicts over 30 million adults in the United States. Treatment and management have changed dramatically over the past 20 years with the introduction of various endovenous therapies, including radiofrequency ablation (RFA) and cyanoacrylate closure using the Venaseal system. In this study, we explore a direct comparison of outcomes between RFA and VenaSeal conducted by a single surgeon within a managed care organization. METHODS: Between May 2020 and December 2021, there were 87 patients undergoing 97 total procedures who were treated with either VenaSeal (n = 55) or RFA (n = 42), conducted by a single surgeon within a managed care organization. Primary outcomes included successful greater saphenous vein (GSV) closure, postoperative deep vein thrombosis (DVT), embolization, saphenofemoral junction (SFJ) thrombosis, skin reaction (allergic or thrombophlebitis), or procedure-related emergency room (ER) and urgent care (UC) visits. Retrospective chart review was conducted to describe patient demographics, indications for treatment, treatment details (number of access sites and indication for treatment), as well as follow-up adjunctive vein procedures (sclerotherapy and stab phlebectomy). RESULTS: All patients had postprocedural ultrasound (US) performed within 7 days by the operating surgeon and mean overall patient follow-up from index procedure was 12 months; 2 patients were lost to follow-up due to death. All operations utilized intraoperative US, and SFJ thrombosis was not observed in any patient postprocedure. The average age of VenaSeal and RFA groups was 59.05 and 59.51 years, respectively. The average number of access sites during the procedure for VenaSeal and RFA was 1.56 and 1.20, respectively. Of the 55 VenaSeal treatments, 9.1% of patients reported postoperative skin reactions, and 9.1% of patients underwent subsequent stab phlebectomy (22 stabs on average). Of the 42 RFA treatments, 7.1% of RFA patients reported postoperative skin reactions, and 9.5% underwent subsequent stab phlebectomy (36 stabs on average). The percentage of patients who had postoperative UC or emergency department visits related to the procedure in the VenaSeal and RFA groups was 3.6% and 0%, respectively. CONCLUSIONS: Both VenaSeal and RFA demonstrated effective vein closure of the GSV at 12-month follow-up, with VenaSeal demonstrating continued noninferiority to RFA. Based on our data, postoperative skin reactions do not appear to be significantly higher with VenaSeal treatment, as previously reported.

Intraprocedural assessment of ablation margins using computed tomography co-registration in hepatocellular carcinoma treatment with percutaneous ablation: IAMCOMPLETE study.

PURPOSE: The primary objective of this study was to determine the feasibility of ablation margin quantification using a standardized scanning protocol during thermal ablation (TA) of hepatocellular carcinoma (HCC), and a rigid registration algorithm. Secondary objectives were to determine the inter- and intra-observer variability of tumor segmentation and quantification of the minimal ablation margin (MAM). MATERIALS AND METHODS: Twenty patients who underwent thermal ablation for HCC were included. There were thirteen men and seven women with a mean age of 67.1 ± 10.8 (standard deviation [SD]) years (age range: 49.1-81.1 years). All patients underwent contrast-enhanced computed tomography examination under general anesthesia directly before and after TA, with preoxygenated breath hold. Contrast-enhanced computed tomography examinations were analyzed by radiologists using rigid registration software. Registration was deemed feasible when accurate rigid co-registration could be obtained. Inter- and intra-observer rates of tumor segmentation and MAM quantification were calculated. MAM values were correlated with local tumor progression (LTP) after one year of follow-up. RESULTS: Co-registration of pre- and post-ablation images was feasible in 16 out of 20 patients (80%) and 26 out of 31 tumors (84%). Mean Dice similarity coefficient for inter- and intra-observer variability of tumor segmentation were 0.815 and 0.830, respectively. Mean MAM was 0.63 ± 3.589 (SD) mm (range: -6.26-6.65 mm). LTP occurred in four out of 20 patients (20%). The mean MAM value for patients who developed LTP was -4.00 mm, as compared to 0.727 mm for patients who did not develop LTP. CONCLUSION: Ablation margin quantification is feasible using a standardized contrast-enhanced computed tomography protocol. Interpretation of MAM was hampered by the occurrence of tissue shrinkage during TA. Further validation in a larger cohort should lead to meaningful cut-off values for technical success of TA.

Time-Driven Activity-Based Cost Comparison of Osteoid Osteoma Ablation Techniques.

OBJECTIVE: Compare the cost of performing an osteoid osteoma ablation using cone beam CT (CBCT) with overlay fluoroscopic guidance to ablation using conventional CT (CCT) guidance and microwave ablation (MWA) to radiofrequency ablation (RFA). METHODS: An 11-year retrospective study was performed of all patients undergoing osteoid osteoma ablation. Ablation equipment included a Cool tip RFA probe (Covidien, Minneapolis, Minnesota) or a Neuwave PR MWA probe (Ethicon, Rariton, New Jersey). The room times as well as immediate recovery time were recorded for each case. Cost analysis was then performed using time-driven activity-based costing for rate-dependent variables including salaries, equipment depreciation, room time, and certain supplies. Time-independent costs included the disposable interventional radiology supplies and ablation systems. Costs were reported for each service providing care and using conventional cost accounting methods with variable and fixed expenditures. RESULTS: A total of 91 patients underwent 96 ablation procedures in either CBCT (n = 66) or CCT (n = 30) using either MWA (n = 51) or RFA (n = 45). The anesthesia induction (22.7 ± 8.7 min versus 15.9 ± 7.2 min, P < .001), procedure (64.7 ± 27.5 min versus 47.3 ± 15.3 min; P = .001), and room times (137.7 ± 33.7 min versus 103.9 ± 22.6. min; P < .001) were significantly longer for CBCT procedures. The procedure time did not differ significantly between MWA and RFA (62.1 ± 27.4 min versus 56.1 ± 23.3 min; P = .27). Multiple regression analysis demonstrated lower age (P = .046), CBCT use (P = .001), RFA use (P = .02), and nonsupine patient position (P = .01) significantly increased the total procedural cost. After controlling for these variables, the total cost of CBCT ($5,981.32 ± $523.93 versus $5,378.93 ± $453.12; P = .001) remained higher than CCT and the total cost of RFA ($5,981.32 ± $523.93 versus $5,674.43 ± $549.14; P = .05) approached a higher cost than MWA. CONCLUSION: The use of CBCT with overlay fluoroscopic guidance for osteoid osteoma ablation resulted in longer in-room times and greater cost when compared with CCT. These cost considerations should be weighed against potential radiation dose advantage of CBCT when choosing an image guidance modality. Younger age, RFA use, and nonsupine patient position additionally contributed to higher costs.

The Cost-Effectiveness of First-Line Cryoablation vs First-Line Antiarrhythmic Drugs in Canadian Patients With Paroxysmal Atrial Fibrillation.

BACKGROUND: The EARLY-AF (NCT02825979), STOP AF First (NCT03118518), and Cryo-FIRST (NCT01803438) randomised controlled trials (RCTs) demonstrated that cryoballoon pulmonary vein isolation reduces atrial fibrillation (AF) recurrence compared with antiarrhythmic drugs (AADs) in patients with symptomatic paroxysmal atrial fibrillation (PAF). The present study developed a cost-effectiveness model (CEM) of first-line cryoablation compared with first-line AADs for PAF, from the Canadian health care payer's perspective. METHODS: Data from the 3 RCTs were analysed to estimate key CEM parameters. The model structure used a decision tree for the first 12 months and a Markov model with a 3-month cycle length for the remaining lifetime time horizon. Costs were set at 2023 Canadian dollars, health benefits were expressed as quality-adjusted life years (QALYs), and both were discounted 3% annually. Probabilistic sensitivity analysis (PSA) considered parameter uncertainty. RESULTS: The statistical analysis estimated that first-line cryoablation generates a 47% reduction (P < 0.001) in the rate of AF recurrence, a 73% reduction in the rate of subsequent ablation (P < 0.001), and a 4.3% (P = 0.025) increase in health-related quality of life, compared with first-line AADs. The PSA indicates that an individual treated with first-line cryoablation accrues less costs (-$3,862) and more QALYs (0.19) compared with first-line AADs. Cryoablation is cost-saving in 98.4% of PSA iterations and has a 99.9% probability of being cost-effective at a cost-effectiveness threshold of $50,000 per QALY gained. Cost-effectiveness results were robust to changes in key model parameters. CONCLUSIONS: First-line cryoballoon ablation is cost-effective when compared with AADs for patients with symptomatic PAF.

Intraprocedural Versus Initial Follow-up Minimal Ablative Margin Assessment After Colorectal Liver Metastasis Thermal Ablation: Which One Better Predicts Local Outcomes?

OBJECTIVES: The aim of this study was to investigate the prognostic value of 3-dimensional minimal ablative margin (MAM) quantified by intraprocedural versus initial follow-up computed tomography (CT) in predicting local tumor progression (LTP) after colorectal liver metastasis (CLM) thermal ablation. MATERIALS AND METHODS: This single-institution, patient-clustered, tumor-based retrospective study included patients undergoing microwave and radiofrequency ablation between 2016 and 2021. Patients without intraprocedural and initial follow-up contrast-enhanced CT, residual tumors, or with follow-up less than 1 year without LTP were excluded. Minimal ablative margin was quantified by a biomechanical deformable image registration method with segmentations of CLMs on intraprocedural preablation CT and ablation zones on intraprocedural postablation and initial follow-up CT. Prognostic value of MAM to predict LTP was tested using area under the curve and competing-risk regression model. RESULTS: A total of 68 patients (mean age ± standard deviation, 57 ± 12 years; 43 men) with 133 CLMs were included. During a median follow-up of 30.3 months, LTP rate was 17% (22/133). The median volume of ablation zone was 27 mL and 16 mL segmented on intraprocedural and initial follow-up CT, respectively ( P < 0.001), with corresponding median MAM of 4.7 mm and 0 mm, respectively ( P < 0.001). The area under the curve was higher for MAM quantified on intraprocedural CT (0.89; 95% confidence interval [CI], 0.83-0.94) compared with initial follow-up CT (0.66; 95% CI, 0.54-0.76) in predicting 1-year LTP ( P < 0.001). An MAM of 0 mm on intraprocedural CT was an independent predictor of LTP with a subdistribution hazards ratio of 11.9 (95% CI, 4.9-28.9; P < 0.001), compared with 2.4 (95% CI, 0.9-6.0; P = 0.07) on initial follow-up CT. CONCLUSIONS: Ablative margin quantified on intraprocedural CT significantly outperformed initial follow-up CT in predicting LTP and should be used for ablation endpoint assessment.

Excess Bed Days and Hospitalization Costs Associated With 30-Day Complications Following Catheter Ablation of Atrial Fibrillation.

BACKGROUND: The incidence and type of complications following catheter ablation of atrial fibrillation have been extensively examined, but the impact associated with these complications on the length of stay and hospitalization costs is unknown. METHODS AND RESULTS: This cohort study included 20 117 adult patients (mean age 62.6±11.4 years, 30.3% women, median length of stay 1 day [interquartile range 1-2 days]) undergoing atrial fibrillation ablation in financial years 2011 to 2017 in Australia with available cost data from the National Hospital Cost Data Collection, which determines government reimbursement of health services provided. The primary outcome was the costs associated with complications occurring up to 30 days postdischarge adjusted for inflation to 2021 Australian dollars. We used generalized linear models to estimate the increase in length of stay and cost associated with complications, adjusting for patient characteristics. Within 30 days of hospital discharge, 1151 (5.72%) patients experienced a complication with bleeding (3.35%) and pericardial effusion (0.75%) being the most common. On average, the occurrence of a complication was associated with an adjusted 3.3 (95% CI, 3.1-3.6) excess bed days of hospital care (totaling 3851 days), and a $7812 (95% CI, $6754-$8870) increase in hospitalization cost (totaling $9.0 million). Most of the total excess cost was attributable to bleeding ($3.8 million, 41.9% of total excess cost) and pericardial effusion ($1.6 million, 18.2%). CONCLUSIONS: Complications following atrial fibrillation ablation were associated with significant increase in length of stay and hospitalization costs, most of which were attributable to bleeding and pericardial effusion. Strategies to improve procedural safety and reduce health care costs should focus on these complications.

Percutaneous ethanol injection in thyroid nodular pathology and metastatic cervical adenopathies: A systematic review, meta-analysis and economic evaluation.

BACKGROUND: Percutaneous ethanol injection (PEI) has been shown to be a valuable treatment for thyroid nodular pathology and metastatic cervical adenopathies. OBJECTIVE: To evaluate the effectiveness, safety, and cost-effectiveness of PEI in thyroid nodular pathology and metastatic cervical adenopathies. METHODS: A systematic review (SR) using meta-analysis was conducted on the effectiveness and safety of PEI. A SR on cost-effectiveness was also performed. The SRs were conducted according to the methodology developed by the Cochrane Collaboration with reporting in accordance with the PRISMA statement. A cost-minimization analysis was carried out using a decision tree model. Assuming equal effectiveness between two minimally invasive techniques (PEI and radiofrequency ablation (RFA)), the model compared the costs of the alternatives with a horizon of six months and from the perspective of the Spanish National Health System. RESULTS: The search identified three RCTs (n=157) that evaluated PEI versus RFA in patients diagnosed with benign thyroid nodules: ninety-six patients with predominantly cystic nodules and sixty-one patients with solid nodules. No evidence was found on other techniques or thyroid nodular pathology. No statistically significant differences were observed between PEI and RFA in volume reduction (%), symptom score, cosmetic score, therapeutic success and major complications. No economic evaluations were identified. The cost-minimization analysis estimated the cost per patient of the PEI procedure at €326 compared to €4781 for RFA, which means an incremental difference of -€4455. CONCLUSIONS: There are no differences between PEI and RFA regarding their safety and effectiveness, but the economic evaluation determined that the former option is cheaper.

Quantitative assessment of transient autonomic modulation after single-shot pulmonary vein isolation with pulsed-field ablation.

INTRODUCTION: Pulmonary vein isolation (PVI) with thermal energy is characterized by concomitant ablation of the surrounding ganglionated plexi (GP). Pulsed-field ablation (PFA) selectively targets the myocardium and seems associated with only negligible effects on the autonomic nervous system (ANS). However, little is known about the dynamic effects of PFA on the GP immediately after PVI. This study sought to investigate the degree and acute vagal modulation induced by the FarapulseTM PFA system during PVI compared with single-shot thermal ablation. METHODS: A total of 76 patients underwent first-time PVI with either FarapulseTM PFA (PFA group, n = 40) or cryoballoon ablation (thermal ablation group, n = 36) for paroxysmal atrial fibrillation (AF). The effect on the ANS in the two groups was assessed before and after PVI with extracardiac vagal stimulation (ECVS). To capture any transient effects of PFA on the ANS, in a subgroup of PFA patients ECVS was repeated at three predefined timepoints: (1) before PVI (T0); (2) immediately after PVI (T1); and (3) 10 min after the last energy application (T2). RESULTS: Despite similar baseline values, the vagal response induced by ECVS after PVI almost disappeared in the thermal ablation group but persisted in the PFA group (thermal group: 840 [706-1090] ms, p < .001 compared to baseline; PFA group: 11 466 [8720-12 293] ms, p = .70 compared to baseline). Intraprocedural vagal reactions (defined as RR increase >50%, transitory asystole, or atrioventricular block) occurred more frequently with PFA than thermal ablation (70% vs. 28%, p = .001). Moreover, heart rate 24 h post-PVI increased more with thermal ablation than with PFA (16.5 ± 9.0 vs. 2.6 ± 6.1 beats/min, p < .001). In the subgroup of PFA patients undergoing repeated ANS modulation assessment (n = 11), ECVS demonstrated that PFA determined a significant acute suppression of the vagal response immediately after PVI (p < .001 compared to baseline), which recovered almost completely within 10 min. CONCLUSION: PVI with the FarapulseTM PFA system is associated with only transitory and short-lasting vagal effects on the ANS which recover almost completely within a few minutes after ablation. The impact of this phenomenon on AF outcome needs to be further investigated.

Percutaneous microwave ablation of hepatic tumors: is there an impact of cirrhotic liver parenchyma upon the volume and short-term assessment of the ablation zone?

OBJECTIVE: To retrospectively compare and evaluate ablation zone volume and its reduction from baseline to 1 month follow-up post-percutaneous microwave ablation (MWA) between healthy and cirrhotic liver parenchyma. METHODS: Institutional database research identified 84 patients (118 hepatic tumors) who underwent percutaneous MWA with the same system. Caudal-right lobe ratio was applied to distinguish cirrhotic (n = 51) and healthy (n = 67) group; ITK-SNAP software was used to quantify ablation zone volume. Long (LAD) and short 1 (SAD-1) and 2 (SAD-2) axis, tumor size diameter (mm) and volume (cm³) of the ablation zones were evaluated for each treated lesion in both groups at baseline (immediately post-ablation) and at 1 month follow-up. RESULTS: There was no significant difference comparing ablation zone volumes at baseline (healthy group: mean ablation volume 14.84 cm³ vs cirrhotic group: mean ablation volume 17.85 cm³, p = 0.31) and 1 month post-ablation (healthy group: mean ablation volume 9.15 cm³ vs cirrhotic group: mean ablation volume 11.58 cm³, p = 0.24). When both "healthy" and "cirrhotic" liver group were evaluated independently, there was a significant difference of ablation volumes reduction (p-value < 0.001) from baseline to 1 month follow-up. When both groups were compared based on reduction (35.12-38.34%) there was no significant difference in ablation zone volumes (p-value = 0.77). CONCLUSION: Percutaneous MWA results in ablation zones of a comparable volume in both healthy and cirrhotic liver parenchyma. Both cirrhotic and healthy liver parenchyma experience a similar significant reduction of ablation zone volume at 1 month post-therapy. ADVANCES IN KNOWLEDGE STATEMENT: This study evaluates and compares the volume of the ablation zone after MWA between healthy and cirrhotic liver parenchyma from baseline to 1 month follow-up and attempts to identify potential differences. It is the first study to demonstrate significant shrinkage of ablation volumes in healthy livers as compared to cirrhotic livers after 4 weeks of follow-up. The results of this study can help us understand the effect of MWA when applied in different backgrounds of liver parenchyma, which could lead to different treatment planning.

Study Protocol STEREOLAB: Stereotactic Liver Ablation Assisted with Intra-Arterial CT Hepatic Arteriography and Ablation Confirmation Software Assessment.

PURPOSE: This study aims to evaluate the technical efficacy and local tumor progression-free survival (LTPFS) of a standardized workflow for thermal ablation of colorectal liver metastases (CRLM) consisting of CT during hepatic arteriography (CTHA)-based imaging analysis, stereotactic thermal ablation, and computer-based software assessment of ablation margins. MATERIALS AND METHODS: This investigator initiated, single-center, single-arm prospective trial will enroll up to 50 patients (≤ 5 CRLM, Measuring ≤ 5 cm). Procedures will be performed in an angio-CT suite under general anesthesia. The primary objective is to estimate LTPFS with a follow-up of up to 2 years and secondary objectives are analysis of the impact of minimal ablative margins on LTPFS, adverse events, contrast media utilization and radiation exposure, overall oncological outcomes, and anesthesia/procedural time. Adverse events (AE) will be recorded by CTCAE (Common Toxicity Criteria for Adverse Events), and Bayesian optimal phase-2 design will be applied for major intraprocedural AE stop boundaries. The institutional CRLM ablation registry will be used as benchmark for comparative analysis with the historical cohort. DISCUSSION: The STEREOLAB trial will introduce a high-precision and standardized thermal ablation workflow for CRLM consisting of CT during hepatic arteriography imaging, stereotactic guidance, and ablation confirmation. Trial Registration ClinicalTrials.gov identifier: (NCT05361551).

Clinical outcomes and cost of open, laparoscopic, and percutaneous ablation for hepatocellular carcinoma.

BACKGROUND: Open (OA), laparoscopic (LA), and percutaneous (PA) ablation are all ablation approaches for hepatocellular carcinoma (HCC) utilized in the United States today. However, it remains unclear today which approach is (A) most effective, (B) cost-efficient, and (C) nationally practiced. METHODS: In-hospital mortality and cost were collected from the National Inpatient Sample (NIS) database for patients undergoing liver ablation from 2011 to 2018. Secondary outcomes included length of stay, disposition, and perioperative composite complications. We used inverse probability of treatment weighting (IPTW) to adjust for differences in patient and hospital baseline characteristics. RESULTS: One thousand and one hundred and twenty-five LA, 1221 OA, and 1068 PA liver ablations were analyzed. After IPTW, in-hospital mortality risk was significantly lower in PA versus OA cohorts (0.57% vs. 2.90%, p < 0.001) and reduced among PA patients, yet not significantly different from the LA cohort (0.57% vs. 1.64%, p = 0.056). The median length of hospital stay was significantly lower in the PA and LA group compared to OA (2 days vs. 6 days, p < 0.001). The median hospitalization costs were significantly lower for PA ($44,884 vs. $90,187, p < 0.001) and LA ($61,445 vs. $90,187, p < 0.001) compared to OA. Moreover, we found significant regional differences regarding the use of each ablation approach, with the Midwest having the lowest rates of PA and LA. CONCLUSIONS: Among patients hospitalized after ablation for HCC, PA leads to the lowest hospital cost. Both PA and LA result in lower peri-operative morbidity and mortality relative to OA. Despite these reported advantages, there are significant regional differences with respect to ablation availability suggesting the need to promote the standardization of best practices.