Saline-enhanced Radiofrequency Research Articles

Potential microemboli formation risk and its management during the heated saline–enhanced radiofrequency needle-tip catheter ablation

BackgroundThe potential risk of embolic events during ablation in the left ventricle (LV) with a heated saline–enhanced radiofrequency (SERF) needle-tip ablation catheter has not been characterized. ObjectiveThis study aimed to investigate the formation of microemboli or other untoward events during SERF ablation. MethodsNinety-three radiofrequency (RF) ablation procedures were performed in the LV of 14 pigs by using a SERF catheter (35 W, 70 seconds, and 60°C; normal or degassed saline [NS or DS] irrigation with a flow rate of 10 mL/min) vs a standard irrigated-tip radiofrequency (S-RF) catheter (30 or 50 W, 30 seconds, and 17 mL/min). Microbubble formation was graded on the basis of intracardiac echocardiography. Microbubbles, microembolic signals, and microparticles were monitored using our established model. ResultsThere was no significant difference in microbubble volume among SERF-NS, SERF-DS, and S-RF 30 W with “grade 1” intracardiac echocardiography microbubbles (median [quartiles] 0.201 [0.011–3.13], 0.455 [0.06–2.66], and 0.004 μL [0.00–0.16 μL], respectively). There was no significant difference in microembolic signals among SERF-NS, SERF-DS, and S-RF 30 W with grade 1 bubbles (n = 8.0 ± 5.8, n = 7.6 ± 4.2, and n = 6.1 ± 6.1, respectively). Both SERF-NS and SERF-DS created larger lesions than did both S-RF 30 W and S-RF 50 W deliveries (mean 1241.5 ± 658.6, 1497.7 ± 893.4, 75.0 ± 24.8, and 184.0 ± 93.8 mm3; P < .001). There was no significant difference in microparticle incidence among groups (P = .675). No evidence of embolic events was found in the brain and other organs at the histology assessment. ConclusionIn the setting of SERF ablation, significantly large LV lesions can be created without any increment in embolic microbubble or particle events. Grade 1 microbubble is related to the efficacy and safety.

Innovations in ventricular tachycardia ablation.

Catheter ablation of ventricular arrhythmias (VAs) has evolved significantly over the past decade and is currently a well-established therapeutic option. Technological advances and improved understanding of VA mechanisms have led to tremendous innovations in VA ablation. The purpose of this review article is to provide an overview of current innovations in VA ablation. Mapping techniques, such as ultra-high density mapping, isochronal late activation mapping, and ripple mapping, have provided improved arrhythmogenic substrate delineation and potential procedural success while limiting duration of ablation procedure and potential hemodynamic compromise. Besides, more advanced mapping and ablation techniques such as epicardial and intramyocardial ablation approaches have allowed operators to more precisely target arrhythmogenic substrate. Moreover, advances in alternate energy sources, such as electroporation, as well as stereotactic radiation therapy have been proposed to be effective and safe. New catheters, such as the lattice and the saline-enhanced radiofrequency catheters, have been designed to provide deeper and more durable tissue ablation lesions compared to conventional catheters. Contact force optimization and baseline impedance modulation are important tools to optimize VT radiofrequency ablation and improve procedural success. Furthermore, advances in cardiac imaging, specifically cardiac MRI, have great potential in identifying arrhythmogenic substrate and evaluating ablation success. Overall, VA ablation has undergone significant advances over the past years. Innovations in VA mapping techniques, alternate energy source, new catheters, and utilization of cardiac imaging have great potential to improve overall procedural safety, hemodynamic stability, and procedural success.

CA-531-04 CANADIAN EXPERIENCE WITH SALINE ENHANCED RADIOFREQUENCY NEEDLE TIP ABLATION FOR VENTRICULAR TACHYCARDIA (SERF VT CANADA TRIAL)

Endocardial catheter ablation for ventricular tachycardia (VT) may fail because of the inability to deliver transmural lesions. Saline-enhanced radiofrequency (SERF) ablation uses a needle tip catheter which is placed at varying depths into the myocardial tissue and heated saline is injected along with radiofrequency (RF) creating fully transmural lesions. We report the first in-human SERF ablation for VT in Canada. The purpose of this study is to describe the prospective outcomes on a seriesof patients undergoing first-in-human SERF ablation for VT in Canada under an Investigational Testing Authorization. Twenty-five patients with ischemic and non-ischemic cardiomyopathy, with recurrent monomorphic drug-refractory VT which had failed a prior catheter ablation underwent SERF ablation in 3 different centers in Canada. After a voltage map, the mapping catheter was replaced with the needle-tipped ablation catheter, which was located perpendicular to the myocardium and extended either 6 or 8 mm into the tissue. Sterile saline solution was infused with a flow rate of 10 ml/min and 60° C and 50 watts of RF was used. LVEF was 33.3% ± 8.6, mean age was 69.5 ± 6.4 years; 92% were male. From 43 clinical VT induced, 42 were attempted and 266 SERF lesions were delivered (10.6 ± 4.9 per patient). At the end of the case, 41 VT were non-inducible (98%) and 24 patients (96%) had their VT eliminated. At 6 months follow-up, VT burden was reduced by 87%. Complications included 2 strokes, 2 pericardial effusion and one patient had ischemic bowel and 1died. SERF ablation is feasible and permits control of symptomatic monomorphic VT in drug-refractory patients with a prior failed ablation.

B-PO03-034 INTRACARDIAC ECHOCARDIOGRAPHY VALIDATION OF SALINE-ENHANCED RADIOFREQUENCY NEEDLE-TIP ABLATION FOR THE CONTROLLABLE CREATION OF TRANSMURAL LESIONS

In saline-enhanced radiofrequency needle-tip (SERF) ablation, heated saline is injected into the myocardium via a needle, while the needle is used as a monopolar ablation electrode. In comparison to lesions created by conventional radiofrequency ablation, lesions created by SERF ablation are larger and more often transmural. With the implementation of SERF ablation, real-time validation of lesion formation is needed for the controllable creation of transmural lesions. The aim of the study was to analyze the ability of 2D-intracardiac echocardiography (ICE) and impedance measurements to detect transmural lesions. Fifty-six SERF energy deliveries at left ventricular sites of 11 dogs guided by 2D-ICE were analyzed (power: 15-50 W; time: 25-120 sec; irrigation saline: 60 °C with 10 mL/min flow rate). Impedance measurements were taken before, during, and after the energy delivery. One week after the ablation procedure, hearts were explanted en bloc for ex-vivo lesion validation. Continuous lesions from the endocardium to the epicardium were defined as transmural lesions. On 2D-ICE, 31 (63.3%) lesions were considered to be transmural. For 23 of these lesions, transmurality was confirmed in gross pathology, resulting in a sensitivity of 70%, a specificity of 47%, a positive predictive value of 74% and a negative predictive value of 59% for detecting transmural lesions. In confirmed transmural lesions, impedance measurements did not differ compared to non-transmural lesions on gross pathology (baseline impedance 85.5 Ω [IQR 79.5 - 95.8] vs. 84.0 Ω [IQR 82.0 - 85.0], p=0.497; impedance after SERF ablation 75.0 Ω [IQR 68.2 - 85.8] vs. 69.0 Ω [IQR 68.0 - 77.0], p=0.297; impedance drop 11.0 Ω [IQR 4.8 - 16.8] vs. 14.0 Ω [IQR 11.0 - 17.0], p=0.289 and impedance drop rate 13.5 % [IQR 5.9 - 16.6] vs. 17.1 % [IQR 13.8 - 19.4], p=0.183). 2D-ICE can potentially be used to guide and validate SERF ablation lesion formation in real-time for the controllable creation of transmural lesions.

Real-time intracardiac echocardiography validation of saline-enhanced radiofrequency needle-tip ablation: lesion characteristics and gross pathology correlation.

With the implementation of saline-enhanced radiofrequency (SERF) needle-tip ablation, real-time validation of lesion formation is needed for the controllable creation of transmural lesions. The aim of the study was to analyse the ability of two-dimensional intracardiac echocardiography (2D-ICE) to guide and validate SERF ablation in real-time. Fifty-six SERF energy deliveries at left ventricular sites of 11 dogs guided by 2D-ICE were analysed (power: 15-50 W; time: 25-120 s; irrigation saline: 60°C with 10 mL/min flow rate). Catheter tip/tissue orientation and lesion formation could be well detected by 2D-ICE in 49 (87.5%) energy deliveries. Gross pathology analysis confirmed excellent 2D-ICE lesion localization, the ability to detect transmural lesions (70% sensitivity, 47% specificity) and positive correlation between 2D-ICE and the corresponding gross pathology measurements of 'maximal lesion depth'; (repeated measures correlation: rrm = 0.43, P = 0.012) and 'depth at maximal lesion width' (D@MW; rrm = 0.51, P = 0.003). The median angle between SERF catheter tip and endocardium was 76° [interquartile range (IQR) 58-83°]. The more perpendicular the catheter tip/tissue orientation was the deeper D@MW (rrm = 0.32, P = 0.045). Grade 3 microbubbles on 2D-ICE during ablation, indicating inadequate catheter tip/tissue contact, was associated with smaller lesion volumes than with Grade 1 microbubbles (284.8 mm3 [IQR 151.3-343.1] vs. 2114.1 mm3 [IQR 1437.0-3026.3], P < 0.001). With excellent lesion localization and a 70% detection rate of transmural lesions, 2D-ICE is well suited to validate SERF ablation lesion formation in real-time. The catheter tip/tissue angle impacts the lesion formation and through perpendicular catheter positioning, deeper intramural areas of the myocardium can be reached.

Impact of myocardial fiber orientation on lesions created by a novel heated saline-enhanced radiofrequency needle-tip catheter: An MRI lesion validation study

Irrigated needle catheter ablation is efficacious for creation of transmural lesions in the left ventricle (LV). However, interdependence of needle orientation and myocardial fiber orientation and the resulting influence on lesion creation remain unclear. The purpose of this study was to investigate the impact of myocardial fiber orientation on reproducibility and controllability of lesion creation in LV myocardium using a heated saline-enhanced radiofrequency (SERF) needle-tip catheter system. Eleven dogs underwent catheter ablation using this novel catheter. Ablative lesions were created using different power and ablation times (15-50 W; application 25-120 seconds; 60°C irrigation saline at 10 mL/min). Hearts were explanted, and lesions were evaluated using 3-T cardiac magnetic resonance (CMR), gross pathologic, and histologic investigations. Forty-three of 57 lesions (75.4%) were transmural, and lesion depth reached approximately 90% of LV wall thickness. Lesion volume in both gross pathology and exvivo CMR showed a positive linear correlation with power × radiofrequency (RF) time index (r = 0.637, P <.001; and r = 0.786, P <.001, respectively). Maximum width (circumferential direction of LV) and maximum length (long-axis direction) of all lesions were distributed in the middle layer of LV where myocardium runs circumferentially. Paired-sample t-test showed maximum lesion width was significantly greater than maximum lesion length by both CMR and gross pathologic evaluation (26.1 ± 9.6 mm vs 17.2 ± 6.7 mm, P <.001; and 22.5 ± 7.7 mm vs 18.6 ± 5.9 mm, P <.001, respectively). This catheter showed feasibility in creating transmural LV lesions. Power × RF time index was strongly correlated with lesion volume and predicted lesion size. More importantly, SERF lesions extended along the myocardial fiber orientation.

Characterization of Warm Saline‐Enhanced Radiofrequency Ablation Lesions in the Infarcted Porcine Ventricular Myocardium

Radiofrequency (RF) ablation of scar-mediated ventricular tachycardia is limited by the size of lesions achieved with conventional catheters. We examined the gross and histopathology characteristics of warm saline-enhanced radiofrequency (SERF) ablation delivered to left ventricular (LV) infarction scars via a novel catheter employing an extendable infusion needle electrode. Yorkshire pigs (n = 14) underwent LV infarction by left anterior descending artery balloon occlusion. After 4-6 weeks, baseline hemodynamic data were obtained and endocardial electroanatomic mapping was performed in 13 surviving animals. Following single, 40 Watt SERF ablations delivered endocardially to the center of infarctions, 4 were examined the same day (day 0). The rest underwent repeat measurements and were sacrificed at 1 week (n = 6), and at 4 weeks (n = 3). Average lesion depth and diameter were: 1.85 ± 0.7 cm and 2.33 ± 0.7 cm at day 0, 0.91 ± 0.1 cm and 1.9 ± 0.4 cm after 1 week, and 1.0 ± 0.2 cm and 1.89 ± 0.76 cm after 4 weeks, respectively. Histopathology at 1 week showed that ablation lesions covered 41 ± 10.6% of the infarct area. SERF ablation lesions extended 100%, 90%, and 68% of the total wall thickness at day 0, 1 week, and 4 weeks, respectively. Hemodynamic parameters were unchanged. There were no myocardial wall perforations or aneurysms. SERF ablation within myocardial infarct tissue produced large, near-transmural lesions, without evidence of myocardial perforation, wall thinning, or aneurysm formation. Ablations did not produce any negative hemodynamic effects in this small group of experiments.

Hypertonic saline-enhanced radiofrequency versus chemoembolization sequential radiofrequency in the treatment of large hepatocellular carcinoma

Large hepatocellular carcinoma (HCC) appears to be a major obstacle for radiofrequency ablation (RFA); therefore, attempts to increase the volume of coagulation by injecting hypertonic saline before and/or during RFA have been made. Transarterial chemoembolization (TACE) combines the effect of targeted chemotherapy with ischemic necrosis and eliminates heat loss if combined with RFA. Our aim was to compare the efficacy of hypertonic saline-enhanced RFA versus TACE sequential RFA in the treatment of medium and large nodular HCC. This prospective study was carried out on 40 patients with 40 HCCs between 2008 and 2010 in the Tropical Medicine and Hepatology Department, Faculty of Medicine, Cairo University. They were divided into two groups (20 patients each): the first group received hypertonic saline-enhanced RFA (RFA+HS) and the second group underwent transarterial chemoembolization, followed by RFA (TACE+RFA). Triphasic computed tomography 1 month after the procedure showed that 17 (85%) patients in each group achieved complete ablation, whereas three (15%) in each group achieved partial ablation. In the RFA+HS group, 12/13 (92%) of medium HCC and 5/7 (71%) of large HCC were successfully ablated. In the TACE+RFA group, 8/8 (100%) medium HCC and 9/12 (75%) of large lesions were successfully ablated. The relation between success rate and lesion diameter was statistically significant only in RFA+HS group. After 6 months, 73.7% of patients in the RFA+HS group and 83.3% of patients in the TACE+RFA group showed maintained ablation (P=0.86). RFA+HS and TACE+RFA are safe and equally effective treatments for medium to large HCC.

Image-guided Tumor Ablation: Standardization of Terminology and Reporting Criteria

The field of interventional oncology with use of image-guided tumor ablation requires standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison between treatments that use different technologies, such as chemical (ethanol or acetic acid) ablation, and thermal therapies, such as radiofrequency (RF), laser, microwave, ultrasound, and cryoablation. This document provides a framework that will hopefully facilitate the clearest communication between investigators and will provide the greatest flexibility in comparison between the many new, exciting, and emerging technologies. An appropriate vehicle for reporting the various aspects of image-guided ablation therapy, including classification of therapies and procedure terms, appropriate descriptors of imaging guidance, and terminology to define imaging and pathologic findings, are outlined. Methods for standardizing the reporting of follow-up findings and complications and other important aspects that require attention when reporting clinical results are addressed. It is the group's intention that adherence to the recommendations will facilitate achievement of the group's main objective: improved precision and communication in this field that lead to more accurate comparison of technologies and results and, ultimately, to improved patient outcomes. The intent of this standardization of terminology is to provide an appropriate vehicle for reporting the various aspects of image-guided ablation therapy.

Large HCC ablation by a new saline-enhanced expandable radiofrequency device

Large HCC ablation by a new saline-enhanced expandable radiofrequency device

Diaphragmatic Hernia After Radiofrequency Ablation Therapy for Hepatocellular Carcinoma

3Department of Radiology, Kitasato University School of Medicine, Sagamihara, Kanagawa 228-8555, Japan. ercutaneous radiofrequency ablation is a novel thermal ablation technique for achieving coagulative necrosis of liver tumors with fewer treatment sessions than percutaneous ethanol injection therapy requires [1, 2]. Several recent developments in radiofrequency ablation technology, such as a high-power (150–200 W) radiofrequency generator, a method for conducting radiofrequency ablation during occlusion of hepatic blood flow, and saline-enhanced radiofrequency ablation techniques, have made it possible to necrotize a larger volume of tissue—3 cm or more in diameter—during a single ablation procedure [3]. Most of the complications after radiofrequency ablation have been minor, but some severe and fatal complications have been reported [4, 5]. In a multicenter study in 2,320 patients with 3,554 lesions [4], six patients (0.3%) died after radiofrequency ablation, including two caused by multiorgan failure following intestinal perforation; one case each of septic shock, tumor rupture, liver failure after bile duct stenosis; and sudden death of unknown cause. Fifty cases (2.2%) of additional major complications were also reported, including 12 (0.5%) of peritoneal bleeding, 12 of tumor seeding, six of hepatic abscess, five of gastrointestinal wall perforation, three of hemothorax, two of rapid hepatic decompensation, and one case each of diaphragmatic paresis, common bile duct stenosis, cardiac arrest, pulmonary embolism, pneumothorax, large biloma, multisegmental hepatic infarction, acute cholestasis, and septicemia. Thermal damage has been documented as a specific complication of radiofrequency ablation. We recently encountered a patient with a diaphragmatic hernia due to thermal damage of the diaphragm. A defect of the diaphragm occurred after radiofrequency ablation for hepatocellular carcinoma (HCC) and remained quiescent for 18 months until bowel herniated through it. To our knowledge, this is the first case in the literature to report diaphragmatic hernia as a complication of radiofrequency ablation. The clinical presentation was acute abdominal pain, whereas MDCT clearly indicated a diaphragmatic defect.

2121: The experiment in vitro of saline-enhanced radiofrequency ablation using a new perfused-cooled dual probe bipolar mode

2121: The experiment in vitro of saline-enhanced radiofrequency ablation using a new perfused-cooled dual probe bipolar mode

Electrosurgical burns in pediatric patients undergoing liver resection with saline-enhanced radiofrequency technology

Use of saline-enhanced radiofrequency (RF) technology reduces blood loss in infants undergoing liver resection. Radiofrequency systems continuously deliver much higher currents for longer periods of time than conventional coagulation instruments and thus increase the risk of complications. Thress infants undergoing liver resection with the newer RF technology at one facility experienced electrosurgical unit (ESU) dispersive pad burns. As a result, an experiment was performed on animal subjects to determine best ESU dispersive pad placement on infants and to gather data on device impedance. Recommendations to prevent burns include central placement of the ESU dispersive pad and activating warming devices only after resection is complete.

Examination: Electrosurgical burns in pediatric patients undergoing liver resection with saline-enhanced radiofrequency technology

AORN JournalVolume 83, Issue 3 p. 665-668 Clinical Examination: Electrosurgical burns in pediatric patients undergoing liver resection with saline-enhanced radiofrequency technology First published: 07 July 2006 https://doi.org/10.1016/S0001-2092(06)60194-4 AORN is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's Commission on Accreditation. AORN is provider-approved by the California Board of Registered Nursing, Provider Number CEP 13019. Check with your state board of nursing for acceptance of this activity for relicensure. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume83, Issue3March 2006Pages 665-668 RelatedInformation

Excessive Hyperthermic Necrosis of a Pulmonary Lobe after Hypertonic Saline-Enhanced Monopolar Radiofrequency Ablation

Although there has been a feasibility study of saline-enhanced radiofrequency ablation of the lung in rabbits, there has been no report on hypertonic saline-enhanced radiofrequency ablation of human pulmonary tumors or its complication. We report a case in which a large necrotic cavity was produced in the lung after hypertonic saline-enhanced radiofrequency ablation of recurrent metastatic tumor from hepatocellular carcinoma. Although hypertonic saline-enhanced radiofrequency ablation is powerful and efficient in local ablation, it is difficult to predict the exact extent of ablation, especially in the lungs. This can be dangerous, as there is a high chance of producing an ablation area much larger than expected and, hence, major complications. Special attention is required not to overablate while using this technique.

Image-guided Tumor Ablation: Standardization of Terminology and Reporting Criteria

The field of interventional oncology with use of image-guided tumor ablation requires standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison between treatments that use different technologies, such as chemical (ethanol or acetic acid) ablation, and thermal therapies, such as radiofrequency (RF), laser, microwave, ultrasound, and cryoablation. This document provides a framework that will hopefully facilitate the clearest communication between investigators and will provide the greatest flexibility in comparison between the many new, exciting, and emerging technologies. An appropriate vehicle for reporting the various aspects of image-guided ablation therapy, including classification of therapies and procedure terms, appropriate descriptors of imaging guidance, and terminology to define imaging and pathologic findings, are outlined. Methods for standardizing the reporting of follow-up findings and complications and other important aspects that require attention when reporting clinical results are addressed. It is the group's intention that adherence to the recommendations will facilitate achievement of the group's main objective: improved precision and communication in this field that lead to more accurate comparison of technologies and results and, ultimately, to improved patient outcomes. The intent of this standardization of terminology is to provide an appropriate vehicle for reporting the various aspects of image-guided ablation therapy.

Assessment of proarrhythmic effects of linear ablation using a novel, injected saline-enhanced radiofrequency energy delivery system

Assessment of proarrhythmic effects of linear ablation using a novel, injected saline-enhanced radiofrequency energy delivery system

Complications After Percutaneous Saline-Enhanced Radiofrequency Ablation of Liver Tumors: 3-Year Experience with 336 Patients at a Single Center

Our objective was to report the complications that occurred in a large series of patients with primary or metastatic liver tumors treated with percutaneous saline-enhanced radiofrequency ablation under sonographic guidance at a single center during 3 years of experience. Between September 2000 and October 2003, 336 consecutive patients (221 men and 115 women; age range, 44-78 years; mean, 67 years) with 407 malignant liver tumors were treated at our institution using radiofrequency ablation. Of these patients, 287 had hepatocellular carcinoma from cirrhosis, 47 had liver metastases (38 from colon, six from breast, two from lung, and one from cutaneous melanoma), and two had primary cholangiocarcinoma. Adverse events related to radiofrequency ablation were prospectively recorded. The number of sessions performed was 375 (39 patients had two sessions). The number of patients with major complications, including death, was three (0.9%). The overall mortality rate was 0.3% (1/336). One patient died because of worsening liver decompensation. Two other major complications occurred. In one patient (0.3%), liver abscess and sepsis developed and were successfully treated with percutaneous sonography-guided needle (18-gauge) aspiration and IV antibiotics. Mild posttreatment ascites occurred in one patient (0.3%). One patient showed self-limiting subcutaneous cellulitis along the electrode-needle path that healed in 2 weeks. Fever lasting 1-3 days and pain lasting 12-24 hr were observed in 141 patients (42%) and 211 patients (63%), respectively. So far, no cutaneous or abdominal wall seeding has been observed clinically or sonographically. Radiofrequency ablation of liver tumors can be considered safe. Life-threatening acute liver failure can be considered a rare possible complication.

Bipolar saline-enhanced electrode for radiofrequency ablation: results of experimental study of in vivo porcine liver.

To evaluate whether a bipolar saline-enhanced radiofrequency (RF) ablation system embedded in one needle is able to consistently produce homogeneous and predictable areas of coagulation necrosis with or without the Pringle maneuver of vascular inflow occlusion. RF ablation (480 kHz) of the liver was performed in 24 healthy pigs by means of laparotomy: group A (n = 5), 4-cm distance between electrodes 1 and 2; group B (n = 7), 4-cm distance and the Pringle maneuver; group C (n = 5), 2-cm distance; and group D (n = 7), 2-cm distance with the Pringle maneuver. Twenty percent NaCl solution was infused continuously at a rate of 100 mL/h via each electrode during the procedure. The pigs were followed up, and they were euthanized on the 7th day. Livers were removed for histologic assessment. Time, impedance, current, power output, specific voltage of the contacts, energy output, temperatures in the liver, volume of the lesion, and energy delivered per lesion volume were determined and compared among groups. Predictability of lesion volume was evaluated with the coefficient of variability. Mean values of the variables were compared among the groups by means of one-way analysis of variance or Kruskall-Wallis test. Impedance at the end of the RF ablation procedure was almost twofold lower than the corresponding initial value in all groups. In Pringle groups B and D, regular ellipsoids of coagulation necrosis were created (mean lesion volume, 149.50 cm3 +/- 34.26 and 69.43 cm3 +/- 15.48, respectively). In non-Pringle groups A and C, the shape of coagulation necrosis was influenced by the vessels encountered, and mean lesion size was lower than that in the Pringle groups (P <.01). The coefficient of variability of lesion size was lower in the Pringle groups (23% and 22%, respectively) than that in the non-Pringle groups (75% and 30%, respectively). The bipolar saline-enhanced RF ablation method produces homogeneous and predictable areas of coagulation necrosis between two electrodes, regardless of the distance between them, preferably with vascular inflow occlusion.

Percutaneous sonographically guided saline-enhanced radiofrequency ablation of hepatocellular carcinoma.

The purpose of our study was to analyze the efficacy, side effects, and short-term complications of saline-enhanced percutaneous radiofrequency ablation performed under sonographic guidance in a series of cirrhotic patients with hepatocellular carcinoma. SUBJECTS AND METHODS. Between September 2000 and June 2002, 84 patients (55 men and 29 women) with cirrhosis who ranged in age from 48 to 74 years (mean age, 64 years) and who had 95 hepatocellular carcinomas (seven patients had two tumors and two patients had three tumors) were treated with high frequency-induced thermotherapy. The diameters of the tumors ranged from 1.5 to 8.5 cm (mean, 3.6 cm). The efficacy of radiofrequency ablation was evaluated with triphasic contrast-enhanced CT performed 4 weeks after the procedure. Posttreatment CT showed complete necrosis in 73 (77%) of 95 hepatocellular carcinomas in 62 patients. Complete necrosis based on tumor size was seen in 40 (95%) of 42 tumors with diameters equal to or smaller than 3 cm, 32 (71%) of 45 tumors with diameters between 3.1 and 5.0 cm, and one (12%) of eight tumors with diameters larger than 5.0 cm. Twenty-two hepatocellular carcinomas showed incomplete necrosis. None of the patients experienced major complications. Four patients were lost to follow-up. The length of the follow-up period ranged from 4 to 22 months (mean, 10 months). One patient died 8 months after the radiofrequency ablation treatment. All the remaining patients are still alive. During the follow-up period, eight (10%) of 80 patients showed a local recurrence on sonography and CT. Our experience suggests that percutaneous radiofrequency ablation of hepatocellular carcinoma with high frequency-induced thermotherapy is safe and effective in the treatment of hepatocellular carcinomas equal to or smaller than 3 cm, fairly effective for hepatocellular carcinomas between 3 and 5 cm, and ineffective for tumors larger than 5 cm.