Radiofrequency Ablation Time Research Articles

Radiofrequency ablation of osteoid osteoma using tissue impedance as a parameter of osteonecrosis

The aim of this study is to assess the safety and the efficacy of radiofrequency ablation (RFA) of osteoid osteoma with Soloist monopolar electrode using tissue impedance, rather than temperature, as an indicator of osteonecrosis. The medical records and imaging studies of 30 patients (males 18, females 12) who underwent RFA of osteoid osteoma at our institution were reviewed. The mean age of the patients was 15.3 years (range 5-34 years) and the mean duration of follow up was 26.9 months (range 3-52 months). The lesions were located in the femur (n=6, 53%), tibia (n = 8, 27%), hand (n = 3, 10%), foot (n = 2, 6%) and humerus (n = 1, 3%). The procedure was performed with general anaesthesia under CT guidance. The nidus was accessed with 11-gauge bone biopsy needle and then the stylet was removed and replaced by monopolar 16.5G radiofrequency probe with a 9-mm active tip through the coaxial axis. Power delivery via the radiofrequency generator was started at 2 W and increased gradually until the end point of 450-500 Ω reached and 'Roll-Off' achieved indicating coagulation necrosis of the target lesion. The procedure was technically successful in all patients. The mean procedure time was 72 min and the mean RFA time was 12.7 min. The clinical success rate was 93%. In one patient, the procedure was abandoned due to immature Roll-Off despite all measures. In one patient (3%), recurrence occurred 39 months after the procedure. No major complications were encountered. Two minor skin burns occurred that were resolved with conservative measures. RFA of osteoid osteoma using Soloist monopolar electrode is a safe and effective treatment. Tissue impedance could be used as an alternative to temperature to indicate osteonecrosis of osteoid osteoma during RFA.

Ethanol infusion in the vein of Marshall facilitates mitral isthmus ablation

Treatment of perimitral flutter (PMF) requires bidirectional mitral isthmus (MI) block, which can be difficult with radiofrequency ablation (RFA). The vein of Marshall (VOM) is located within the MI. To test whether VOM ethanol infusion could help achieve MI block. Perimitral conduction was studied in patients undergoing ablation of atrial fibrillation. Group 1 included 50 patients with a previous atrial fibrillation ablation undergoing repeat ablation, 30 of whom had had MI ablation. Spontaneous (8 of 50) or inducible PMF (21 of 50) was confirmed by activation mapping. Group 2 included 21 patients undergoing de novo VOM ethanol infusion. The VOM was cannulated with a quadripolar catheter for pacing and with an angioplasty balloon to deliver up to four 1-mL infusions of 98% ethanol. Voltage maps were created before and after VOM ethanol infusion. Bidirectional MI block was verified by differential pacing. RFA times required to achieve it were assessed. In group 1, VOM ethanol infusion acutely terminated PMF in 5 of 29 patients. RFA needed to achieve bidirectional MI block was 2.2 ± 1.6 minutes. Presence of PMF or previous MI ablation did not affect RFA times. In group 2, RFA needed to achieve bidirectional MI block was 2.0 ± 1.6 minutes (P = NS). Five patients had bidirectional MI block achieved solely by VOM ethanol infusion without RFA. In both groups, ablation after VOM ethanol infusion was required in the annular aspect of the MI. There were no acute complications. VOM ethanol infusion is useful in the treatment of PMF and assists in reliably achieving bidirectional MI block.

Long-term durable oncologic outcomes after radiofrequency ablation for T1 renal cell carcinoma.

384 Background: Long-term oncologic outcomes for radiofrequency ablation (RFA) of renal cell carcinoma (RCC) are limited. The objective of this study was to assess the long-term oncological efficacy of RFA for treatment of renal cell carcinoma. Methods: Between 1998 and 2008, 311 biopsy-proven RCC were treated with RFA in 274 patients. Exclusion criteria included history of prior RCC or known metastatic RCC at time of RFA (n=92). 26 patients were lost to follow-up prior to their 6-month imaging study. We retrospectively reviewed the long-term oncologic outcomes for 193 patients. Mean follow-up was 4.6 yrs (range 1–12, SD 2.3). Results: Median age was 71 years (IQR: 63 –79 years). Median Charlson Score was 5.46 (IQR: 5–6). Median size of tumor treated was 3 cm (IQR: 2–3.9 cm, range 1–7.1cm) and 64 of these tumors (33%) were endophytic. Tumor breakdown by stage was T1a: n=153 (79%), T1b: n=37 (19%), and T2: n=3 (2%). Initial treatment success rate was 89%. There were 6 local recurrences (3%) in 4 patients with T1b disease and 2 patients with T2 disease with an average time-to-recurrence of 2.9 years (SD 0.7). 95% of patients with T1a RCC were disease free at last follow-up, in comparison to 81% of those with T1b and 33% of those with T2 disease (p=0.008). At last follow-up 178 (92%) patients were disease-free. 16 (8.2%) developed metastatic disease and 4 patients (2%) died of RCC. Mean disease-free survival was 4.3 years (SD 2.4). Conclusions: In patients who are poor surgical candidates, RFA results in durable local control and a low risk of disease recurrence in T1 RCC. Higher stage, however, correlates with a decreased disease free survival and alternate treatments should be considered when counseling these patients.

The Modified Ablation Guided by Ibutilide Use in Chronic Atrial Fibrillation (MAGIC‐AF) Study: Clinical Background and Study Design

Beyond pulmonary vein isolation (PVI), adjuvant ablation at the sites of complex fractionated atrial electrograms (CFAE) has been shown to improve the long-term success of catheter ablation of persistent atrial fibrillation (AF). However, this approach often requires extensive ablation due to the widespread distribution of CFAE within the left atrium. An optimal strategy would identify areas of CFAE which, when selectively targeted with ablation, result in AF termination with an acceptable long-term freedom from AF. It is possible that the intraprocedural administration of an antiarrhythmic drug may help accomplish this. The Modified Ablation Guided by Ibutilide Use in Chronic AF (MAGIC-AF) Study is an international multicenter prospective randomized double-blinded clinical trial assessing the utility of the intraprocedural administration of 0.25 mg of intravenous ibutilide before performing CFAE ablation. The primary efficacy endpoint of this study will be the freedom from AF at 1 year after a single procedure off antiarrhythmic agents. Safety endpoints will include procedural and radiofrequency ablation time as well as overall procedural complication rate. Patients undergoing a first ever catheter ablation procedure for persistent AF will be included. Individuals with hypertrophic cardiomyopathy, complex congenital heart disease including atrial septal defects, and ejection fraction <35% will be excluded from the study. All patients will first undergo PVI. Those patients who remain in AF will then be randomized in a 1:1 fashion to receive either 0.25 mg intravenous ibutilide or saline placebo followed by a CFAE based ablation strategy. Two hundred randomized patients will be enrolled in this study-100 in each study arm. The MAGIC-AF study will assess the utility of a combined pharmaco-ablative strategy in patients with persistent AF undergoing a CFAE based ablation strategy.

Irrigated-tip vs conventional-tip catheters for primary ablation of posteroseptal and right free-wall accessory pathways: a prospective randomized study

Background The use of irrigated-tip catheters enables elimination of almost all accessory pathways (APs) resistant to standard radiofrequency ablation (RFA). However, effi cacy of irrigation catheter technology in the initial AP ablation has not been studied systematically yet.Objectives We tested whether the externally irrigated-tip catheters are more eff ective than the conventional-tip catheters for initial RFA of the posteroseptal and right free-wall APs, i.e. where application of the conventional RFA is expected to have a lower success rate.Methods Fifty consecutive patients (39 ± 12 years, 32 males), who were subjected to primary catheter-ablation of the posteroseptal or right freewall AP were randomly assigned to RFA with an externally irrigated-tip catheter (group I, n = 25; 45°C/40 W outside the coronary sinus (CS) and 45°C/30 W inside the CS) or a conventional-tip catheter (group C, n = 25; 60°C/60 W outside and 55°C/35 W inside the CS).Results No signifi cant diff erence was identifi ed between groups I and C with respect to acute success rate (88% vs 96%), number of radiofrequency applications (6.8 ± 4.7 vs 6.1 ± 4.3), RFA time (373 ± 242 sec vs 365 ± 241 sec), energy (11022 ± 7833 J vs 12870 ± 11414 J), fl uoroscopy time (669 ± 443 sec vs 789 ± 578 sec) and recurrence rate (18.2% vs 16.7%). The only complication was encountered in group I, manifested as AV-block I-II° after elimination of the right posteroseptal AP.Conclusions Irrigated-tip catheters are not more effi cient than conventional catheters in initial RFA of the posteroseptal and right free-wall APs. Therefore, the use of irrigated-tip catheters is justifi able only for ablation of the APs resistant to previously attempted conventional RFA.

Radiofrequency ablation for treatment of atrial fibrillation.

Atrial Fibrillation (AF) is the most common cardiac arrhythmia which represents a major public health problem. The main purpose of this research is to evaluate the Radiofrequency (RF) ablation effects in the patients with chronic AF scheduled for cardiac surgery because of different heart diseases. The descriptive and prospective study was conducted on 60 patients with AF scheduled for surgery along with RF ablation. The data were collected by questionnaire and included: patients' age, sex, NYHA class, operation type, past medical history, type and cause of valvular heart disease, preoperative ECG (electrocardiogram), duration of surgery, clamping time, cardiopulmonary bypass, and RF ablation time. RF ablation was followed by the main operation. The follow up examination, ECG, and echocardiography were performed 3 and 6 months after operation. The mean age of patients was 48±10 years (18-71 years). Forty one patients had permanent AF and 19 had the persistent AF. The left ventricular ejection fraction was 48.27±9.75 percent before operation, and reached to 56.27±7.87 percent after the surgery (P<0.001). The mean NYHA class before the surgery was 2.83±0.68 which decreased to 1.34±0.46 6 months after the surgery with RF ablation (P<0.001). One patient (1.6%) died after surgery. Complete relief and freedom from AF recurrence was observed in 70% of patients in the mean follow up in 7 months after the surgery. The sinus rhythm with efficient atrial contraction was established in 100% of discharged patients. RF ablation is an effective procedure to cure atrial fibrillation in patients undergoing cardiac surgeries.

Four‐dimensional transcatheter intraarterial perfusion MRI monitoring of radiofrequency ablation of rabbit VX2 liver tumors

To investigate the hypothesis that four-dimensional (4D) transcatheter intraarterial perfusion (TRIP) magnetic resonance imaging (MRI) can quantify immediate perfusion changes after radiofrequency (RF) ablation in rabbit VX2 liver tumors. Nine New Zealand White rabbits were used to surgically implant VX2 liver tumors. During ultrasound-guided RF ablation, tumors received either a true or sham ablation. After selective catheterization of the left hepatic artery under x-ray fluoroscopy, we acquired pre- and post-RF ablation 4D TRIP MR images using 3 mL of 2.5% intraarterial gadopentetate dimeglumine. Two regions-of-interest were drawn upon each tumor to generate signal-intensity time curves. Area under the curve (AUC) was calculated to provide semiquantitative perfusion measurements that were compared using a paired t-test (α = 0.05). Ablated tissue was visually confirmed on pathology using Evans blue dye. Mean AUC perfusion of VX2 tumors for the true ablation group decreased by 92.0% (95% confidence interval [CI]: 83.3%-100%), from 1913 (95% CI: 1557, 2269) before RF ablation to 76.6 (95% CI: 18.4, 134.8) after RF ablation (a.u., P < 0.001). Sham-ablated tumors demonstrated no significant perfusion changes. 4D TRIP MRI can quantify liver tumor perfusion reductions in VX2 rabbits after RF ablation. This MRI technique can potentially be used to improve tumor response assessment at the time of RF ablation.

Recurrence rates and factors for recurrence after radiofrequency ablation combined with transarterial chemoembolization for hepatocellular carcinoma: a retrospective cohort study

There have been reports that radiofrequency ablation (RFA) combined with transarterial chemoembolization (TACE) is as equally effective as surgical resection for the treatment of hepatocellular carcinoma (HCC). This study aimed to evaluate recurrence rate and risk factor of recurrence after RFA combined with TACE for early stage HCC. We reviewed the medical records of the patients who were diagnosed with early stage HCC between March 2006 and August 2008 at Korea University Medical Center and treated with RFA combined with TACE for curative intent (n=65). Recurrence rate was 40% (26 cases) and the time to recurrence was 14.9months. Cumulative recurrence rate at 1year was 20% (13 cases) and at 2years was 33.8% (22 cases). Significant variables for recurrence were: (1) RFA repeated more than one session at initial therapy (P<0.001) and (2) size of main lesion ≥2cm (P=0.047). The recurrence rate of combination therapy was considerably high. Regardless of the therapy used, careful post-RFA follow-up is needed, especially if additional treatment is required after the first session or if the main lesion is ≥2cm at the time of RFA.

Safety and Efficacy of Radiofrequency Ablation for Hepatocellular Adenoma

To investigate the safety and efficacy of radiofrequency (RF) ablation for the treatment of hepatocellular adenoma (HCA). From 2000 to 2009, 170 patients with HCA were referred to a single tertiary hepatobiliary center. Medical records of 18 patients treated with RF ablation were retrospectively analyzed. All patients were female, and the majority had a history of hormonal contraceptive use. Ten patients (56%) had multiple HCAs, with a median number of two lesions (range, one to 12) per patient. Median size of HCA at the time of RF ablation was 3.0 cm (range, 0.8-7.3 cm). A total of 45 HCAs were ablated in 32 sessions (open, n = 4; percutaneous, n = 28). RF ablation was complete after the first session in 26 HCAs (57.8%), and the majority of patients underwent multiple RF ablation sessions to fully ablate all HCAs. Major complications developed in two patients. RF ablation can be used effectively in the treatment of HCA. However, multiple sessions are often required, and signs of residual adenoma might persist in some patients despite repetitive treatment. RF ablation might be especially beneficial in cases not amenable to surgery or in patients who would require major hepatic resection otherwise.

Hepatectomy for recurrent colorectal liver metastases after radiofrequency ablation

The results of surgery for recurrent colorectal liver metastases (CLM) after radiofrequency ablation (RFA) have not been evaluated. From 1993 to 2009, data on patients who underwent resection or RFA for recurrent CLM were collected prospectively. Inclusion criteria for this study were RFA as initial treatment for CLM and resection of recurrent CLM after RFA. Postoperative results and oncological outcomes were analysed. Twenty-eight patients (median number of tumours 1 (1-3), median size 2·8 (2·0-4·0) cm) met the inclusion criteria. Of these, 22 had recurrence at the site of RFA only, two developed new lesions, whereas four had both recurrent and de novo metastases. At the time of resection, patients had a median of 1 (1-13) CLM with a median maximum tumour diameter of 5·0 (1·8-11·0) cm, significantly larger than at the time of RFA (P = 0·021). Ninety-day postoperative morbidity and mortality rates were 46 per cent (13 of 28) and 7 per cent (2 of 28) respectively. After a median follow-up of 35 (0-70) months, 3-year overall and disease-free survival rates calculated by Kaplan-Meier analysis were 60 and 29 per cent respectively. Plasma carcinoembryonic antigen level over 5 ng/ml at the time of resection and a rectal primary tumour were associated with worse survival (P = 0·041 and P = 0·021 respectively). Resection for recurrence after RFA is associated with significant morbidity and modest long-term benefit.

Percutaneous Radiofrequency Ablation for Pulmonary Metastases from Hepatocellular Carcinoma: Results of a Multicenter Study in Japan

Purpose To retrospectively evaluate technical success, effectiveness, complications, patient survival, and prognostic factors with percutaneous radiofrequency (RF) ablation for pulmonary metastases resulting from hepatocellular carcinoma (HCC). Materials and Methods Thirty-two patients from six institutions were included, with a total of 83 pulmonary metastases treated in 65 sessions. RF ablation was always performed percutaneously with computed tomography (CT) guidance. Primary endpoints were technical success and technique effectiveness. Technique effectiveness was evaluated based on sequential follow-up CT images. Secondary study endpoints were complications, patient survival, and determination of prognostic factors. Complications were classified as major or minor. Prognostic factors were determined by analyzing multiple variables with the log-rank test. Results Technical success rate was 100%. Primary technique effectiveness rates were 92% each at 1, 2, and 3 years. Major and minor complications occurred after 16 (25%) and 23 (35%) of the 65 sessions, respectively. The median follow-up period was 20.5 months. Overall survival rates were 87% at 1 year and 57% each at 2 and 3 years (median and mean survival times, 37.7 mo and 43.2 mo, respectively). Significantly better survival rates were obtained in cases of (i) no viable intrahepatic recurrence ( P < .001), (ii) Child-Pugh class A disease ( P < .001), (iii) absence of liver cirrhosis ( P < .001), (iv) absence of hepatitis C virus infection ( P = .006), and (v) α-fetoprotein level of 10 ng/mL or lower ( P = .007) at the time of RF ablation. Conclusions RF ablation appears effective, with an acceptable safety profile, in selected patients with pulmonary metastases resulting from HCC.

A Cross-Sectional Analysis of the Prevalence of Barrett's Esophagus in Otolaryngology Patients With Laryngeal Symptoms

BACKGROUND: Radiofrequency ablation (RFA) is an endoscopic ablation modality that typically requires multiple treatment sessions to fully eliminate dysplastic tissue. It is unclear if increasing experience reduces complications or the necessary number of ablation sessions, and how many ablations are necessary to achieve competence. AIM: To assess the learning curve for physicians performing RFA. METHODS: This was a retrospective study of patients treated with RFA for BE at a tertiary care referral center between June 2006 and November 2010. Pertinent information was extracted from medical records, including: demographics, pre-ablation histology, indicators of GERD activity (symptoms, erosive esophagitis), upper endoscopy findings (Prague criteria, hiatus hernia), ablation outcomes (elimination of metaplasia and dysplasia), and complications (stricture, bleeding). Endoscopist experience was measured by the number of treatment sessions performed prior to initiation of therapy for each patient. Patients with incomplete treatment and those who initiated treatment in the last 6 months were excluded. Patient characteristics and treatment outcomes were examined among 4 quartiles of endoscopist experience by non-parametric tests (Fisher's exact test for categorical variables and Kruskal-Wallis one-way ANOVA for continuous variables). Linear regression and Pearson's correlation were performed to assess the strength of the association between endoscopist experience and number of sessions necessary for complete ablation. RESULTS: Among 305 RFA treatments by 3 physicians in 113 patients, 245 treatments were in 77 patients who completed therapy more than 6 months prior and were included in the analysis. Over time, there was a significant reduction in the number of RFA sessions and time required to complete therapy, from an average of 4.4 sessions and 226 days in the earliest quartile to 2.3 sessions and 111 days in the most recent quartile (p<0.05 for both). Operator experience and number of RFA sessions to complete treatment were significantly correlated(r=0.38, p<0.001). Linear regression identified operator experience (p<0.001) and Prague M length (p<0.001) as independent predictors of number of treatment sessions to complete eradication of BE. By this model, an endoscopist needs to perform 81 ablations to average 3.0 treatments per patient. Complication rates did not differ significantly dependent on operator experience (p=0.26). CONCLUSIONS: There was a clinically and statistically significant learning curve associated with endoscopic ablation of BE, with initial subjects requiring approximately 2.1 additional treatment sessions for complete ablation. After 81 ablations an endoscopist is projected to average 3.0 treatments per patient. For optimal delivery, this procedure should be performed in high volume centers.

Yield of TransNasal Endoscopy in an Unselected General Medical Population

BACKGROUND: Radiofrequency ablation (RFA) is an endoscopic ablation modality that typically requires multiple treatment sessions to fully eliminate dysplastic tissue. It is unclear if increasing experience reduces complications or the necessary number of ablation sessions, and how many ablations are necessary to achieve competence. AIM: To assess the learning curve for physicians performing RFA. METHODS: This was a retrospective study of patients treated with RFA for BE at a tertiary care referral center between June 2006 and November 2010. Pertinent information was extracted from medical records, including: demographics, pre-ablation histology, indicators of GERD activity (symptoms, erosive esophagitis), upper endoscopy findings (Prague criteria, hiatus hernia), ablation outcomes (elimination of metaplasia and dysplasia), and complications (stricture, bleeding). Endoscopist experience was measured by the number of treatment sessions performed prior to initiation of therapy for each patient. Patients with incomplete treatment and those who initiated treatment in the last 6 months were excluded. Patient characteristics and treatment outcomes were examined among 4 quartiles of endoscopist experience by non-parametric tests (Fisher's exact test for categorical variables and Kruskal-Wallis one-way ANOVA for continuous variables). Linear regression and Pearson's correlation were performed to assess the strength of the association between endoscopist experience and number of sessions necessary for complete ablation. RESULTS: Among 305 RFA treatments by 3 physicians in 113 patients, 245 treatments were in 77 patients who completed therapy more than 6 months prior and were included in the analysis. Over time, there was a significant reduction in the number of RFA sessions and time required to complete therapy, from an average of 4.4 sessions and 226 days in the earliest quartile to 2.3 sessions and 111 days in the most recent quartile (p<0.05 for both). Operator experience and number of RFA sessions to complete treatment were significantly correlated(r=0.38, p<0.001). Linear regression identified operator experience (p<0.001) and Prague M length (p<0.001) as independent predictors of number of treatment sessions to complete eradication of BE. By this model, an endoscopist needs to perform 81 ablations to average 3.0 treatments per patient. Complication rates did not differ significantly dependent on operator experience (p=0.26). CONCLUSIONS: There was a clinically and statistically significant learning curve associated with endoscopic ablation of BE, with initial subjects requiring approximately 2.1 additional treatment sessions for complete ablation. After 81 ablations an endoscopist is projected to average 3.0 treatments per patient. For optimal delivery, this procedure should be performed in high volume centers.

The Effect of Operator Experience on Treatment of Dysplastic Barrett's Esophagus With Radiofrequency Ablation

BACKGROUND: Radiofrequency ablation (RFA) is an endoscopic ablation modality that typically requires multiple treatment sessions to fully eliminate dysplastic tissue. It is unclear if increasing experience reduces complications or the necessary number of ablation sessions, and how many ablations are necessary to achieve competence. AIM: To assess the learning curve for physicians performing RFA. METHODS: This was a retrospective study of patients treated with RFA for BE at a tertiary care referral center between June 2006 and November 2010. Pertinent information was extracted from medical records, including: demographics, pre-ablation histology, indicators of GERD activity (symptoms, erosive esophagitis), upper endoscopy findings (Prague criteria, hiatus hernia), ablation outcomes (elimination of metaplasia and dysplasia), and complications (stricture, bleeding). Endoscopist experience was measured by the number of treatment sessions performed prior to initiation of therapy for each patient. Patients with incomplete treatment and those who initiated treatment in the last 6 months were excluded. Patient characteristics and treatment outcomes were examined among 4 quartiles of endoscopist experience by non-parametric tests (Fisher's exact test for categorical variables and Kruskal-Wallis one-way ANOVA for continuous variables). Linear regression and Pearson's correlation were performed to assess the strength of the association between endoscopist experience and number of sessions necessary for complete ablation. RESULTS: Among 305 RFA treatments by 3 physicians in 113 patients, 245 treatments were in 77 patients who completed therapy more than 6 months prior and were included in the analysis. Over time, there was a significant reduction in the number of RFA sessions and time required to complete therapy, from an average of 4.4 sessions and 226 days in the earliest quartile to 2.3 sessions and 111 days in the most recent quartile (p<0.05 for both). Operator experience and number of RFA sessions to complete treatment were significantly correlated(r=0.38, p<0.001). Linear regression identified operator experience (p<0.001) and Prague M length (p<0.001) as independent predictors of number of treatment sessions to complete eradication of BE. By this model, an endoscopist needs to perform 81 ablations to average 3.0 treatments per patient. Complication rates did not differ significantly dependent on operator experience (p=0.26). CONCLUSIONS: There was a clinically and statistically significant learning curve associated with endoscopic ablation of BE, with initial subjects requiring approximately 2.1 additional treatment sessions for complete ablation. After 81 ablations an endoscopist is projected to average 3.0 treatments per patient. For optimal delivery, this procedure should be performed in high volume centers.

Radiofrequency ablation as an adjunct to systemic chemotherapy for colorectal pulmonary metastases

We read with interest the article by Chua et al and would like to share the belief that the combination of chemotherapy and radiofrequency ablation (RFA) offers the potential for disease control in patients with colorectal pulmonary metastases. In fact, in our institution, 74 (94.9%) of 78 consecutive patients with colorectal cancer who received RFA for the treatment of pulmonary metastases received systemic chemotherapy after RFA. The 1year and 3-year overall survival rates were 83.9% (95% confidence interval [95% CI], 92.7%-75.2%) and 56.1% (95% CI, 70.5%-41.7%), respectively, and the median survival time was 38.0 months in all patients. In the article by Chua et al, the survival curve was plotted only between patients treated with and without adjunctive systemic chemotherapy (the median survival times were 59 months and 21 months, respectively, as shown in Figure 5 in their article), although the presence of extrapulmonary metastases at the time of RFA treatment, identified as a negative predictive factor for patient survival in both studies, was found to be significantly dominant (P 1⁄4 .019 using the chi-square test) in our study cohort compared with that of Chua et al (24 of 78 patients and 16 of 100 patients, respectively). This finding might also support the benefit of systemic chemotherapy as an adjunct to RFA in patients with pulmonary metastases from colorectal cancer in multimodality therapy. With regard to a prospective randomized trial to compare metastasectomy and RFA, which Chua et al mentioned as a valid trial in the last part of their discussion, we launched a multicenter randomized controlled trial of surgical metastasectomy versus RFA in patients with resectable colorectal lung metastases in October 2008 in Japan. However, the recruitment of candidates was troublesome because most of the patients preferred RFA to surgical treatment and refused to join in this phase 3 trial. Therefore, we changed it to a 1-arm phase 2 clinical trial for RFA in patients with resectable colorectal lung metastases in October 2009 (NCT00776399). We are expecting a favorable survival outcome in this ongoing trial compared with previous studies of multimodality therapy including pulmonary resection because patients with extrapulmonary metastases at the time of RFA or lymph node swelling are excluded from enrollment.

Radiofrequency ablation of coronary sinus-dependent atrial flutter guided by fractionated mid-diastolic coronary sinus potentials

BackgroundThe efficacy of radiofrequency (RF) ablation of an uncommon coronary sinus (CS)-dependent atrial flutter (AFL) was evaluated using conventional electrophysiological criteria in a highly selected subset of patients with typical and atypical AFL.MethodsFourteen patients with atrial flutter (11 males, mean age 69 ± 9 years) without previous right or left atrial RF ablation were included. Heart disease was present in eight patients. Baseline ECG suggested typical AFL in 12 patients and atypical AFL in two. Mean AFL cycle length was 324 ± 64 ms at the time of RF ablation in the CS. Lateral right atrium activation was counterclockwise (CCW) in 13 patients and clockwise in one. CS activation was CCW in all. Criteria for CS ablation included the presence of CS mid-diastolic fractionated atrial potentials (APs) associated with concealed entrainment with a postpacing interval within 20 ms. Success was defined as termination of AFL and subsequent noninducibility.ResultsThe initial target for ablation was the cavotricuspid isthmus (CTI) in 11 patients and the CS with further CTI ablation in three. AP duration at the CS target site was 122 ± 33 ms, spanning 40 ± 12% of the AFL cycle length. CS ablation site was located 1–4 cm from the CS ostium. Ablation was successful in all patients. Mean time to AFL termination during CS ablation was 39 ± 52 s (<20 s in eight patients). No recurrence of ablated arrhythmia occurred during a follow-up of 18 ± 8 months.ConclusionsThe CS musculature is a critical part of some AFL circuits in patients with typical and atypical AFL. AFL can be terminated in patients with CS or CTI/CS AFL reentrant circuits by targeting CS mid-diastolic fragmented APs.

235 HEPATOCELLULAR CARCINOMA AND UNDERLYING LIVER CIRRHOSIS; INFLUENCE ON TREATMENT OR A PROGNOSTIC VALUE?

Background: Despite its benign nature, hepatocellular adenomas (HA) have a potential for malignant degeneration or spontaneous rupture and bleeding. Therefore, surgical resection is the treatment of choice in selected patients. However, radio frequency ablation (RFA) could offer a viable alternative, and might prevent these patients from undergoing major hepatic surgery with associated morbidity and costs. Aim: To investigate the safety and efficacy of RFA for the treatment of HA. Methods: From 2000 to 2009, 168 patients diagnosed with HA in a tertiary hepato-biliary centre were included in a database. For patients undergoing RFA, clinicopathologic data with regard to diagnosis, treatment and outcome were collected. RFA was considered successful if no residual HA tissue was visualized on contrast enhanced CT or MRI 4–6 weeks post-RFA. Results: Of 61 patients undergoing treatment for HA, 17 patients (28%) underwent RFA. Mean age was 29 years. All patients were female with a history of hormonal contraceptive use. Nine patients (53%) had multiple HA, with a median number of 2 lesions (range 1–10) per patient. Median size of the largest HA at the time of RFA was 3.9 cm (range 1.5–6.7). 39 lesions were ablated in 25 sessions (open n=5, percutaneous n =20). Complete remission was acquired in eight patients after one (n =4) or two (n =4) RFAsessions. Another five patients (29%) had radiological evidence of residual HA tissue (≤15mm) bordering the thermal lesion, but due to low clinical importance no further treatment was administered. All of these lesions have remained stable or regressed during followup. Four patients are currently awaiting further therapy or followup. Post-operatively, one patient developed a liver abscess requiring re-intervention and one patient suffered from amajor but reversible complication related to concomitant hemi-hepatectomy. Median hospital stay was 7 days in the open group and 2 days in the percutaneous group. Conclusion: HA can be safely treated using both open and percutaneous RFA. However, often multiple sessions are required and signs of residual adenoma persist in some patients despite repetitive treatment. RFA might be especially beneficial for patients not amenable for surgery or those that would require major hepatic resection otherwise.

Ablative therapies for renal tumors

Owing to an increased use of diagnostic imaging for evaluating patients with other abdominal conditions, incidentally discovered kidney masses now account for a majority of renal tumors. Renal ablative therapy is assuming a more important role in patients with borderline renal impairment. Renal ablation uses heat or cold to bring about cell death. Radiofrequency ablation and cryoablation are two such procedures, and 5-year results are now emerging from both modalities. Renal biopsy at the time of ablation is extremely important in order to establish tissue diagnosis. Real-time temperature monitoring at the time of radiofrequency ablation is very useful to ensure adequacy of ablation.

821 SMALL RENAL MASS NEEDLE CORE BIOPSY: OUTCOMES OF NON-DIAGNOSTIC PERCUTANEOUS BIOPSY AND ROLE OF REPEAT BIOPSY

You have accessJournal of UrologyKidney Cancer: Localized I1 Apr 2010821 SMALL RENAL MASS NEEDLE CORE BIOPSY: OUTCOMES OF NON-DIAGNOSTIC PERCUTANEOUS BIOPSY AND ROLE OF REPEAT BIOPSY Michael Leveridge, Daniel Shiff, Hannah Chung, Laura Legere, Kimberly Fernandes, Andrew Evans, John Kachura, Antonio Finelli, and Michael Jewett Michael LeveridgeMichael Leveridge More articles by this author , Daniel ShiffDaniel Shiff More articles by this author , Hannah ChungHannah Chung More articles by this author , Laura LegereLaura Legere More articles by this author , Kimberly FernandesKimberly Fernandes More articles by this author , Andrew EvansAndrew Evans More articles by this author , John KachuraJohn Kachura More articles by this author , Antonio FinelliAntonio Finelli More articles by this author , and Michael JewettMichael Jewett More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.1522AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Percutaneous needle core biopsy is becoming established in the management of small renal masses ≤4 cm (SRMs). Numerous recent series have reported success rates of ≥80% with excellent predictive accuracy. Indeterminate or non-diagnostic results continue to be a problem. We present the results of a large biopsy series with outcomes of the non-diagnostic biopsies. METHODS A prospectively maintained database of patients undergoing renal mass biopsy was analyzed to determine the pathology and outcomes of SRM biopsies. Reports of “indeterminate” results included insufficient material, normal kidney or non-renal tissue. Repeat biopsy has recently been recommended and the correlation with the first biopsy as well as outcome were analyzed. RESULTS Three hundred sixteen (316) biopsies were performed (SRM mean diameter 2.5 cm) between January 2000 and October 2009. Biopsy was diagnostic in 266 cases (84.2%) and non-diagnostic in 50 cases (15.8%). Among diagnostic biopsies, 203 (76.3%) were malignant, 95.1% of which were renal cell carcinoma (RCC). Histologic subtyping and grading of RCC was possible in 87.6% and 62.7% of cases, respectively. Seven (7/50 or 14%) of the non-diagnostic biopsies were taken at the time of radiofrequency ablation. Four patients underwent surgical resection of the mass, and 23 were managed by active surveillance. Repeat biopsy was performed in 11 of the 50 non-diagnostic cases, and a diagnosis was possible in 10 (91%). Eight lesions were malignant, and 2 were oncocytic neoplasms. Larger tumor size and a solid nature were found to predict a successful biopsy. Minor complications were experienced in 10.3% of cases, with no major bleeding noted, and no seeding of the biopsy tract. CONCLUSIONS Percutaneous biopsy can be performed safely and accurately in the investigation of renal masses 4cm or less in size. In those cases in which the biopsy is indeterminate, repeat biopsy can be performed with similar accuracy, thus providing a diagnosis in the majority of patients. Toronto, Canada© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e321 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Michael Leveridge More articles by this author Daniel Shiff More articles by this author Hannah Chung More articles by this author Laura Legere More articles by this author Kimberly Fernandes More articles by this author Andrew Evans More articles by this author John Kachura More articles by this author Antonio Finelli More articles by this author Michael Jewett More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Efficacy of multi-electrode duty-cycled radiofrequency ablation for pulmonary vein disconnection in patients with paroxysmal and persistent atrial fibrillation

A novel multi-electrode pulmonary vein ablation catheter (PVAC) combining circular mapping and duty-cycled multi-electrode radiofrequency (RF) energy delivery has been developed to map and isolate the pulmonary veins (PVs). The aim of this study was to assess the efficacy of multi-electrode RF ablation using the PVAC device. A total of 102 consecutive patients, age 57.9 +/- 9.6 years, with paroxysmal or persistent drug refractory atrial fibrillation (AF) were referred for ablation. All patients had documented AF episodes with an AF duration of 9.3 +/- 7.5 years (range 1.5-25). The mean total procedure time was 139.30 +/- 37.72 (median 135, range 115-172). The mean fluoroscopy time required for PVAC ablation was 17 +/- 12 min (median 16, range 12-33) and the total fluoroscopy time was 32.1 +/- 11.3 min (median 29, range 25-39). The mean multi-electrode RF ablation time required to achieve complete PV isolation was 31 +/- 6.7 min (range 16-51). In eight patients with persistent AF, additional ablations were performed to defragment septal and posterior part of the left atrium. In five patients additional RF ablations using conventional catheters were necessary. After multi-electrode duty-cycled RF ablation, 62 of 102 (60.8%) patients were in sustained sinus rhythm without anti-arrhythmic drugs. The mean follow-up duration was 12.2 +/- 3.9 months (range 6-15). This novel multi-electrode ablation technique can be used for PV isolation and left atrium ablation with a relatively low medium-term success rate after the first ablation of approximately 61%. Larger studies with longer follow-up are required to evaluate the efficacy and whether multi-electrode RF ablation is associated with a different complication rate compared with standard PV isolation.