Efficacy Of Radiofrequency Ablation Research Articles

03:27 PM Abstract No. 202 Safety and efficacy of radiofrequency ablation with cementoplasty in the palliative treatment of sacral metastases using a thermal protection technique

03:27 PM Abstract No. 202 Safety and efficacy of radiofrequency ablation with cementoplasty in the palliative treatment of sacral metastases using a thermal protection technique

Patient satisfaction of radiofrequency ablation for symptomatic benign solid thyroid nodules: our experience for 2-year follow up

BackgroundThe patient satisfaction of symptoms improvement and disease factors that may affect long-term treatment efficacy of radiofrequency ablation (RFA) for non-functioning solid benign thyroid nodules (TNs) over a 2-year follow up study was investigated.MethodsThis retrospective study evaluated 194 non-functioning solid benign TNs of 103 patients. The TNs were categorized as small (≤5 ml), medium (5.1 to 13 ml), intermediate (13.1 to 30 ml) and large (over 30 ml) according to the initial volume of TNs before ablation. Clinical evaluation and contrast-enhanced ultrasound (CEUS) were carried out before ablation and the follow up at 1, 3, 6 months and every 6 months after ablation. All patients were asked to assess the cosmetic score (1–4 scores) and symptom score (0–10 scores) before ablation and every follow up after ablation.ResultsAll patients underwent RFA without any major complications. The mean treatment sessions were 1.5 ± 0.6. 98 nodules required a single session (98/194, 50.5%), 87 required two sessions (87/194, 44.9%), 9 required three sessions (9/194, 4.6%). The average follow up months were 16.3 ± 5.6 (range, 6–24 months) and no nodule regrew in our study. After RFA treatment, the TNs volume significantly decreased (P < 0.001). The small group of nodules shrunk larger compared to the medium, intermediate and large groups (P < 0.001). Cosmetic signs and pressure symptoms were significantly improved, particularly in the intermediate and large groups (P < 0.05).ConclusionsRFA is effective for treating non-functioning solid benign TNs and controlling clinical symptoms with a low complication rate during 2 years follow up. The reduction rate was related to the initial volume of nodules. Patients were satisfied with cosmetic signs and pressure symptoms improvement, particularly in the intermediate and large groups. However, multiple RFA treatments should be used in larger nodules to achieve the desired clinical outcomes.

Efficacy of Radiofrequency Ablation versus Transarterial Chemoembolization for Patients with Solitary Hepatocellular Carcinoma ≤3 cm

Optimal treatment for small hepatocellular carcinoma (HCC) ≤ 3 cm remains controversial. Ablation and chemoembolization are considered for nonoperative candidates. This study compares survival among patients with solitary HCC ≤ 3 cm treated with radiofrequency ablation (RFA) and transarterial chemoembolization (TACE). Patients diagnosed with HCC ≤ 3 cm between 2005 and 2014 were included. Kaplan-Meier survival functions with log-rank tests were used to estimate recurrence-free survival and overall survival (OS) survival. Among 161 patients with solitary HCC ≤ 3 cm, 145 patients with mean age of 65.2 years (±9.2) and 95 per cent prevalence of cirrhosis had operative treatment or TACE, and/or RFA. From this cohort, 27 (19%) patients had TACE, 27 (19%) patients had RFA, and 15 (10%) patients had TACE/RFA. The patients treated with definitive TACE, RFA, or TACE/RFA had a similar 1-year recurrence-free survival (23% vs 27% vs 36%, respectively, P = 0.445) and similar 5-year OS (21% vs 24% vs 33%, respectively, P = 0.287). Thirty-five (24%) patients were bridged to transplantation with TACE and/or RFA. The 5-year OS was significantly improved in patients bridged to transplantation (P < 0.001). Survival does not differ between patients with solitary HCC ≤ 3 cm treated with TACE or RFA. Patients who were bridged to transplantation had significantly greater OS compared with patients who were not transplanted.

Enhancement of the efficacy of radiofrequency ablation by neoadjuvant oncolytic virus therapy via antitumor immunity and the booster effect of immune checkpoint inhibitors.

253 Background: A third generation oncolytic herpes simplex virus type 1, G47Δ, destroys tumor cells selectively and induces antitumor immune responses. Radiofrequency ablation (RFA) is a standard local therapy for hepatocellular carcinoma (HCC). Here, we examined the efficacy of G47Δ used in combination with RFA and evaluated the antitumor immune responses. Methods: In A/J mice harboring bilateral poorly immunogenic Neuro2a subcutaneous tumors, tumors on one side were treated with intratumoral injections with G47Δ (2×106 pfu) on days 0, 2 and 4 followed by RFA treatment on day 6, which results in complete regression of the treated tumors. We further treated with an immune checkpoint inhibitor (ICI) in combination. Tumor infiltrating lymphocytes in contralateral tumors were analyzed with flow cytometric analysis. To examine the contribution of CD8+ T cells, CD8+ T cells were depleted by treatment with anti-CD8 monoclonal antibody. To mimic a remote recurrence, unilateral subcutaneous tumors were treated with G47Δ and RFA, and Neuro2a cells were implanted on the same day of RFA. In a separate experiment without rechallenge, antitumor immunity was evaluated using ELISpot assay on day 20. Results: The G47Δ+RFA treatment caused smaller volumes of contralateral tumors and increased infiltration of CD8+/CD45+ T cells within the tumor, compared with RFA or G47Δ monotherapy. Without CD8+ T cells, the antitumor effect on the contralateral tumors was completely abolished. When mice were rechallenged, those cured by G47Δ+RFA rejected the Neuro2a more frequently than those cured by RFA alone. ELISpot assay revealed that the number of Neuro2a reactive splenocytes was significantly greater in the G47Δ+RFA group than the RFA group. The G47Δ+RFA+anti-PD-L1 treatment caused smaller volumes of contralateral tumors compared with G47Δ+RFA treatment, whereas anti-PD-L1 alone showed no effect. Conclusions: Intratumoral administration of G47Δ prior to RFA would enhance systemic antitumor immunity that is further enhanced by ICI.

Efficacy of radiofrequency ablation and microwave ablation in the treatment of thoracic cancer: A systematic review and meta-analysis.

BackgroundRadiofrequency ablation and microwave ablation are frequently prescribed for thoracic cancer. However, few writers have been able to draw on any systematic research into the differences between the two ablation methods.MethodsA literature search was carried out using Embase, PUBMED, Web of Science, Cochrane Library, and CNKI databases, with additional searches carried out manually using terms associated with thoracic cancer and thermal ablation. Then we used Google Scholar for a complementary search. Data were extracted from studies of patients that underwent radiofrequency ablation or microwave ablation, and the investigator carried out efficacy evaluation and follow up. The data obtained from the literature were summarized and analyzed using Cochrane Revman software Version 5.3 and SPSS 22.0.ResultsThere were seven comparative studies, but no randomized studies identified for data extraction; 246 patients received radiofrequency ablation therapy and 319 controls received microwave ablation. There was no significant difference in the six‐month, one‐year, two‐year, and three‐year survival rates, and adverse reactions were found in the two treatments. For patients’ long‐term survival rate, the two treatments can achieve a similar survival time.ConclusionIn the treatment of thoracic cancer, microwave ablation can achieve the same efficacy as radiofrequency ablation.

Trends in lumbar radiofrequency ablation utilization from 2007 to 2016

BACKGROUND CONTEXTLumbar radiofrequency ablation (RFA) is an intervention used to treat facet-mediated chronic low back pain. In some studies with methods consistent with clinical practice guidelines, RFA results in improvements in pain and functional limitations. However, in other studies, RFA demonstrates limited benefit. Despite unanswered questions regarding efficacy of RFA, its use is widespread. PURPOSETo describe trends in the utilization and cost of lumbar RFA and lumbar facet injections. STUDY DESIGN/SETTINGRetrospective cohort study. PATIENT SAMPLEThe sample was derived from the IBM/Watson MarketScan Commercial Claims and Encounters Databases from 2007 to 2016. OUTCOME MEASURESLongitudinal trends in the distribution and quantity of lumbar facet injections before lumbar RFA, corticosteroid administration during lumbar facet injections, progression to lumbar RFA after lumbar facet injections, lumbar RFA utilization, and costs of these interventions. METHODSTwo primary cohorts were identified from patients who received lumbar RFA or lumbar facet injection procedures. Utilization rates per 100,000 enrollees were determined for both cohorts. The mean, median, and interquartile ranges of the number of facets targeted and costs per procedure were calculated by year and laterality, as well as overall. Costs in 2018 dollars were estimated by summing gross payment totals from patients and insurance plans. This study was supported by funds from the NIH, and has no conflict of interest associated biases. RESULTSFrom 2007 to 2016, lumbar RFA sessions performed per 100,000 enrollees per year increased from 49 to 113, a 130.6% overall increase (9.7% annually). Lumbar facet injection use increased from 201 to 251 sessions per 100,000 enrollees, a 24.9% overall increase (2.5% annually). In the year after a lumbar facet injection, 26.7% of patients received lumbar RFA; 28.6% received another injection but not RFA; and 44.7% received neither. The number of patients receiving two lumbar facet injection procedures prior to lumbar RFA grew from 51.1% in 2010 to 58.8% in 2016. For lumbar RFA, the cost per 100,000 enrollees went from $94,570 in 2007 to $266,680 in 2016, a 12.2% annual increase. For lumbar facet injections, the cost per 100,000 enrollees went from $257,280 in 2007 to $396,580 in 2016, a 4.9% annual increase. CONCLUSIONSThis analysis showed consistent growth in both the frequency and procedure cost of lumbar RFA and facet injections among a large, national, commercially insured population from 2007 to 2016.

Comparative study of efficacy of radiofrequency ablation, electrodesiccation, and cryosurgery in the treatment of cutaneous warts

Background: Even though the older and most common treatment for the wart is a destructive method, there is no published randomized control trial comparing the efficacy of radiofrequency ablation, electrodesiccation, and cryosurgery in warts. Objective: The objective of the study is to compare the efficacy and adverse effect of radiofrequency ablation, electrodesiccation, and cryosurgery in the treatment of cutaneous warts. Methods: It was a randomized control trial. Seventy-five patients were randomly divided into three groups of radiofrequency ablation A (Group A), electrodesiccation (Group B), and cryosurgery (Group C) with a sample size of 25 per group by the computer-generated randomized table. Clinical cases of common and plane warts with age >12 years were included in the study. The assessment was based on the reduction of the total surface area of the reference lesion(s), pigmentation, scarring, reappearance of dermatoglyphics, and patient's satisfaction. Results: Complete cure in Group A was 22 (95%), in Group B was 17 (73%), and in Group C was 14 (58%) which was statistically significant (P ≤ 0.001). Majority (>90%) of the patients were very much satisfied with treatment outcome, particularly with radiofrequency which was statistically significant (P = 0.001). Conclusion: Radiofrequency was seen to have the highest cure rate.

The efficacy of radiofrequency ablation in the management of liver tumours (Systematic Review)

The efficacy of radiofrequency ablation in the management of liver tumours (Systematic Review)

The Efficacy of Radiofrequency Ablation in the Management of Liver Tumours (Systematic Review)

The Efficacy of Radiofrequency Ablation in the Management of Liver Tumours (Systematic Review)

Efficacy of radiofrequency ablation for recurrent hepatocellular carcinoma after hepatectomy in elderly

Background/Aim In recent aging society, ultrasonography guided radiofrequency ablation (RFA) has been performed as a low invasive treatment against hepatocellular carcinoma (HCC) in elderly patients. We investigated the efficacy of RFA against recurrent HCC after surgical resection in elderly patients, retrospectively. Material/Methods From 2000 to 2015, 86 patients with recurrent HCC, who were treated with surgical resection as an initial treatment for HCC, were enrolled. HCCs were within Milan criteria and all were treated with RFA. Elderly were defined as 75 years old or more (elderly-group: n = 25 and non-elderly group: n = 61). Clinical background and prognosis were analyzed. Results Average age of elderly-group were 78.9 ± 3.5 years old, while that of non-elderly were 63.9 ± 8.9 years old (P Conclusion RFA can be performed as an effective and low invasive therapy against recurrent HCC after surgical resection in elderly patients as well as non-elderly patients.

Assessment of Radiofrequency Ablation Efficacy for Hepatocellular Carcinoma by Histology and Pretransplant Radiology

Radiofrequency ablation (RFA) represents a potentially curative option for early-stage hepatocellular carcinoma (HCC). This study aims at evaluating the histologic response after RFA of small HCCs arising in cirrhosis. Data were reviewed from 78 patients with de novo HCCs who were treated with RFA and subsequently transplanted. The last radiological assessment before liver transplantation (LT) was used for comparison between modified Response Evaluation Criteria in Solid Tumors (mRECIST) and histological findings. A total of 125 de novo HCCs (median diameter, 20 mm) were treated with RFA only in 92 sessions. There were 98 nodules that did not show local recurrence during follow-up (78.4%), and the remaining were retreated, except 1 because of subsequent LT. On explanted livers, complete pathological response (CPR) was observed in 61.6%, being 76.9% when <2 cm, 55.0% when 2-3 cm, and 30.8% when >3 cm. Tumors near hepatic vessels had CPR in 50% of patients versus 69.3% for tumors distant from vessels (P = 0.039). Of the 125 HCCs, 114 had available radiological assessment within a median of 3 months before LT. Complete radiological response, according to mRECIST, was observed in 77.2% of nodules before LT. The Cohen κ was 0.48 (moderate agreement). The overall accuracy was 78.1%. A total of 18 complications were recorded with only 1 graded as major. In conclusion, RFA can provide high CPR for HCC, especially in smaller tumors distant from hepatic veins or portal branches. The agreement between mRECIST and histology is only moderate. Further refinements in radiological assessment are essential to accurately assess the true effectiveness of RFA.

Evaluation of liver lesions by use of shear wave elastography and computed tomography perfusion imaging after radiofrequency ablation in clinically normal dogs.

OBJECTIVE To evaluate acute changes of the liver by use of shear wave elastography (SWE) and CT perfusion after radiofrequency ablation (RFA). ANIMALS 7 healthy Beagles. PROCEDURES RFA was performed on the liver (day 0). Stiffness of the ablation lesion, transitional zone, and normal parenchyma were evaluated by use of SWE, and blood flow, blood volume, and arterial liver perfusion of those regions were evaluated by use of CT perfusion on days 0 and 4. All RFA lesions were histologically examined on day 4. RESULTS Examination of the SWE color-coded map distinctly revealed stiffness of the liver tissue, which increased from the normal parenchyma to the transitional zone and then to the ablation zone. For CT perfusion, blood flow, blood volume, and arterial liver perfusion decreased from the transitional zone to the normal parenchyma and then to the ablation zone. Tissue stiffness and CT perfusion variables did not differ significantly between days 0 and 4. Histologic examination revealed central diffuse necrosis and peripheral hyperemia with infiltration of lymphoid cells and macrophages. CONCLUSIONS AND CLINICAL RELEVANCE Coagulation necrosis induced a loss of blood perfusion and caused tissue hardening (stiffness) in the ablation zone. Hyperemic and inflammatory changes of the transitional zone resulted in increased blood perfusion. Acute changes in stiffness and perfusion of liver tissue after RFA could be determined by use of SWE and CT perfusion. These results can be used to predict the clinical efficacy of RFA and to support further studies, including those involving hepatic neoplasia.

Durability of radiofrequency ablation for treatment of esophageal squamous cell neoplasia: 5-year follow-up of a treated cohort in China

Radiofrequency ablation (RFA) is an accepted treatment for flat Barrett's neoplasia. Less is known about RFA for esophageal squamous cell neoplasia (ESCN). Our group has reported several prospective studies of RFA for ESCN in China with promising results through 12 months of follow-up. In this cohort study we aimed to evaluate longer term outcomes after RFA for ESCN. Patients with flat unstained lesions (USLs) on Lugol's endoscopy containing moderate-/high-grade intraepithelial neoplasia (MGIN/HGIN) or mucosal cancer were treated with RFA every 3 months until complete remission (CR; no MGIN or a worse histologic grade). Patients with CR at 12 months (CR12) were included for follow-up and underwent annual Lugol's endoscopy with biopsy sampling and re-RFA for flat USLs. The clinical course of patients with persistent ESCN at 12 months (treatment failures) is also reported. Among the 78 patients in CR12, 67 (86%) had sustained CR during a median of 48 months (interquartile range, 48-48) of follow-up and 5 endoscopies (interquartile range, 4-6). Recurrence occurred in 7 of 78 patients (9%; MGIN, n= 6; HGIN, n= 1); all lesions were managed with RFA. Four other patients (5%) had progression (to HGIN, n= 1; submucosal esophageal squamous cell carcinoma, n= 3). During follow-up protocol violations occurred in 46 of 78 patients (59%). Of the 12 treatment failures, progression occurred in 6. Overall, 2 patients developed subepithelial disease that was not visible after Lugol's endoscopy. Based on post-hoc analysis, the pink-color sign at baseline (a pink color change after Lugol's endoscopy) significantly predicted failure after RFA. RFA is relatively easy to apply and can efficiently treat large areas with ESCN. Despite protocol violations that may have interfered with the efficacy of RFA in 59% of patients, most patients with CR12 had sustained CR during follow-up. However, some patients progressed to advanced disease and 2 developed subepithelial disease, not visible after Lugol's endoscopy. Based on currently available data, we advise the restriction of the use of RFA for flat MGIN and HGIN without the pink-color sign on Lugol's chromoendoscopy. (Clinical trial registration number: NCT02047305.).

Efficacy of radiofrequency ablation in treatment of complicated pyogenic liver abscess

Objective To evaluate the efficacy of radiofrequency ablation (RFA) in treatment of complicated pyogenic liver abscess (PLA). Methods A retrospective analysis was conducted on 20 patients with complicated PLA treated from August 2010 to January 2018 in the West Campus of Beijing Chao-yang Hospital which is Affiliated to the Capital Medical University and Rizhao Central Hospital of Shandong Province. These patients were treated with RFA based treatment modalities using CT-guided or laparoscopy combined with Ultrasound-guided RFA. The successful rate, efficacious rate and safety of RFA were respectively analyzed. Routine follow-up was carried out after treatment. Results The successful rate of RFA was 100%. The median operation time was 45 minutes. All the 20 patients were cured by one session of RFA. The multilocular lesion in one patient was converted to a unilocular lesion after one session of RFA. The patient was then cured by percutaneous hepatic abscess drainage. No serious complications were observed. Conclusions RFA was safe and efficacious. It should be considered as an alternative treatment for patients with complicated PLA who were not responsive to, or not applicable to antibiotics treatment and radiological intervention. Key words: Pyogenic liver abscess (PLA); Radiofrequency ablation (RFA); Therapy

Serum miR-130b level, an ideal marker for monitoring the recurrence and prognosis of primary hepatocellular carcinoma after radiofrequency ablation treatment

ObjectiveThis study was aimed to explore the potential roles of miR-130b for the efficacy of radiofrequency ablation (RFA) in patients with primary hepatocellular carcinoma (PHC). MethodsThe serum sample of 110 PHC patients, which underwent RFA treatment, was collected on 1d pre-operation (Pre 1), 7d (POD 7) and 14d post-operation (POD 14). qRT-PCR was used to detect miR-130b expression. The relationship between miR-130b expression and clinicopathological features, postoperative recurrence and survival rate were analyzed. ResultsThe liver function of PHC patients was improved after RFA treatment. The level of alpha fetoprotein (AFP) was gradually reduced on POD 7 and POD 14 (all P < 0.05). Before RFA, the expression of miR-130b in PHC patients was upregulated, while the expression of miR-130b decreased significantly with time after RFA treatment. And high expression of miR-130b was closely related to cirrhosis (P = 0.027) and tumor differentiation degree (P < 0.01). Serum miR-130b levels were significantly higher in patients with recurrence than in patients without recurrence (P < 0.05). Patients were divided into two groups according to miR-130b expression level (median ΔCt), compared with low ΔCt group, the incidence of recurrence in high ΔCt group was significantly higher after RFA (P = 0.020). Kaplan-Meier survival analysis showed that the survival rate of high ΔCt group was significantly shorter than that of low ΔCt group (P < 0.001). ConclusionOur study provided evidence that serum miR-130b level may be used as an ideal marker for monitoring the recurrence and prognosis of PHC after RFA treatment.

Efficacy of radiofrequency ablation of hepatocellular carcinoma prior to liver transplantation and the need for competing-risk analysis

Radiofrequency ablation (RFA) currently represents a potentially curative treatment for hepatocellular carcinoma (HCC) in its early stages (1,2). Providing higher rates of complete necrosis of target tumor than other loco-regional therapies (LRTs), RFA plays an important role as bridge therapy to liver transplantation (LT) (3). In the study from Lee and colleagues of the UCLA medical center, published in issue of June 2017 of Hepatology, Authors analyzed the outcome of 121 patients with 156 de-novo HCC treated with RFA as initial stand-alone therapy (4). The study is a fair attempt to analyze the efficacy of RFA as bridge therapy to LT, considering all potential outcome measures. Nevertheless, some results passed unnoticed, while instead deserve further discussion.

Expert consensus on image-guided radiofrequency ablation of pulmonary tumors: 2018 edition.

Lung cancer ranks first in incidence and mortality in China. Surgery is the primary method to cure cancer, but only 20–30% of patients are eligible for curative resection. In recent years, in addition to surgery, other local therapies have been developed for patients with numerous localized primary and metastatic pulmonary tumors, including stereotactic body radiation therapy and thermal ablative therapies through percutaneously inserted applicators. Percutaneous thermal ablation of pulmonary tumors is minimally invasive, conformal, repeatable, feasible, cheap, has a shorter recovery time, and offers reduced morbidity and mortality. Radiofrequency ablation (RFA), the most commonly used thermal ablation technique, has a reported 80–90% rate of complete ablation, with the best results obtained in tumors < 3 cm in diameter. Because the clinical efficacy of RFA of pulmonary tumors has not yet been determined, this clinical guideline describes the techniques used in the treatment of localized primary and metastatic pulmonary tumors in nonsurgical candidates, including mechanism of action, devices, indications, techniques, potential complications, clinical outcomes, post‐ablation surveillance, and use in combination with other therapies. In the future, the role of RFA in the treatment of localized pulmonary tumors should ultimately be determined by evidence from prospective randomized controlled trials comparing sublobar resection or stereotactic body radiation therapy.

Radiofrequency ablation combined with esophageal stent in the treatment of malignant esophageal stenosis: A single-center prospective study.

The purpose of this study was to investigate the efficacy of radiofrequency ablation (RFA) combined with esophageal stent in treating malignant esophageal stenosis. Seventy patients with malignant esophageal obstruction treated in Department of Gastroenterology from April 2013 to April 2015 in China-Japan Union Hospital of Jilin University were enrolled. They were randomly assigned into the treatment group (radiofrequency ablation combined with esophageal stent) and control group (esophageal stent). To observe the degree of dysphagia, esophageal stenosis diameter, readmission time, adverse events and complications. There was no significant differences in dysphagia and esophageal diameter between the treatment group and the control group within 1–3 months after operation (P>0.05), and the degree of dysphagia and esophageal diameter in the treatment group at postoperative 6 months were better than those in the control group (P=0.018 and 0.038, respectively). The readmission time of the treatment group was also better than that of the control group (P=0.021). The adverse events and complications included hemorrhage, perforation and esophageal stent displacement. No significant differences in adverse events and complications between the treatment group and the control group were observed. All patients were successfully treated during hospitalization. Effect of radiofrequency ablation combined with esophageal stent implantation was better than esophageal stent implantation in the treatment of malignant esophageal stenosis, but it had no effect on the survival time.

A comparison of microwave thermosphere versus radiofrequency thermal ablation in the treatment of colorectal liver metastases

BackgroundMicrowave thermosphere ablation (MTA) is a new generation technology. The aim of this study was to compare the efficacy of MTA and radiofrequency ablation (RFA) in achieving local tumor control in patients with colorectal liver metastasis (CRLM). MethodsThis was a retrospective study of a prospective ablation database. Fifty-four patients with 155 CRLM lesions underwent RFA and 51 patients with 121 lesions underwent MTA. Patients were managed by a multidisciplinary team. Clinical and oncologic data were analyzed. Kaplan–Meier and Cox Proportional Hazards model were used for statistical analysis. ResultsDemographics were similar between the two groups. Total ablation and operative times were significantly shorter in MTA group (19 vs. 37 mins, p < 0.001, 154 vs. 202 mins, p = 0.009). With a similar hospital stay (median 1), 90-day morbidity was similar (8 vs. 10%, p = 0.848), without mortality. Local recurrence (LR) rate per lesion was 20% in RFA and 10% in MTA group (p = 0.020). On Cox Proportion Hazards model, ablation modality and tumor size were independent predictors of LR. ConclusionsThis is the first study comparing the efficacy of RFA and MTA on CRLM. The results suggest that compared to RFA, MTA improves local tumor control, while significantly shortening operative time.

Longer Duration Versus Increasing Power During Radiofrequency Ablation Yields Different Ablation Lesion Characteristics.

The goal of this study was to characterize differences in ablation lesions with varying radiofrequency ablation (RFA) power and time. Increasing power delivery or prolonging duration can improve the efficacy of RFA. However, the extent to which ablation lesion characteristics change, based on varying degrees of power and duration, is unknown. An exvivo model consisting of viable bovine myocardium in a circulating warmed saline bath was used. An open irrigated RFA catheter was positioned with 10 g of force in the perpendicular position, and RFA was delivered at powers of 20, 30, 40, and 50 W and for various time intervals, up to a total of 90 s, at each power. An invivo porcine thigh preparation model was used to perform RFA at 50 W for 5 s and 20 W for 30 s. Lesion volumes were analyzed. Greater power delivery and longer radiofrequency time increased ablation lesion size. However, compared with a proportional change in radiofrequency duration, the same proportional increase in power produced a significantly larger lesion volume (p< 0.01). For invivo models, 50 W/5 s ablation lesions yielded similar volumes but significantly less depth than 20 W/30 s ablation lesions. Peak temperatures were not significantly different at 2 and 4 mm with 50 W/5 s versus 20 W/30 s. Varying power and duration will confer different ablation lesion characteristics that can be tailoredaccording to the substrate/anatomy that is being ablated. This phenomenon has important implications during catheter ablation.