Efficacy of transcatheter embolization/chemoembolization （TAE/TACE） for the treatment of single hepatocellular carcinoma

AIM: To investigate the efficacy of transcatheter embolization/chemoembolization (TAE/TACE) in cirrhotic patients with single hepatocellular carcinoma (HCC) not suitable for surgical resection and percutaneous ablation therapy. METHODS: A cohort of 176 consecutive cirrhotic patients with single HCC undergoing TAE/TACE was reviewed; 162 patients had at least one image examination (helical CT scan or triphasic contrast-enhanced MRI) after treatment and were included into the study. TAE was performed with Lipiodol followed by Gelfoam embolization; TACE was performed with Farmorubicin prepared in sterile drip at a dose of 50 mg/m(2), infused over 30 min using a peristaltic pump, and followed by Lipiodol and Gelfoam embolization. RESULTS: Patients characteristics were: mean age, 62 years; male/female 117/45; Child-Pugh score 6.2 +/- 1.1; MELD 8.7 +/- 2.3; mean HCC size, 3.6 (range 1.0-12.0) cm. HCC size class was 6.0 cm, n = 14. Patients received a total of 368 TAE/TACE (mean 2.4 +/- 1.7). Complete tumor necrosis was obtained in 94 patients (58%), massive (90%-99%) necrosis in 16 patients (10%), partial (50%-89%) necrosis in 18 patients (11%) and poor (< 50%) necrosis in the remaining 34 patients (21%). The rate of complete necrosis according to the HCC size class was: 69%, 69%, 52%, 68%, 50% and, 13% for lesions of 6.0 cm, respectively. Kaplan-Mayer survival at 24-mo was 88%, 68%, 59%, 59%, 45%, and 53% for lesions of 6.0 cm, respectively. CONCLUSION: Our study showed that in cirrhotic patients with single HCC smaller than 6.0 cm, TAE/TACE produces complete local control of tumor in a significant proportion of patients. TAE/TACE is an effective therapeutic option in patients with single HCC not suitable for surgical resection or percutaneous ablation therapies. Further studies should investigate if the new available embolization agents or drug eluting beads may improve the effect on tumor necrosis.     

Radiofrequency ablation improves prognosis compared with ethanol injection for hepatocellular carcinoma < or =4 cm

BACKGROUND & AIMS: The aim of this study was to compare the clinical outcome of percutaneous radiofrequency (RF) ablation, conventional percutaneous ethanol injection (PEI), and higher-dose PEI in treating hepatocellular carcinoma (HCC) 4 cm or less. METHODS: A total of 157 patients with 186 HCCs 4 cm or less were randomly assigned to 3 groups (52 patients in the conventional PEI group, 53 in the higher-dose PEI group, and 52 in the RF group). Clinical outcomes in terms of complete tumor necrosis, overall survival, local tumor progression, additional new tumors, and cancer-free survival were compared across 3 groups. RESULTS: The rate of complete tumor necrosis was 88% in the conventional PEI group, 92% in the higher-dose PEI group, and 96% in the RF group. Significantly fewer sessions were required to achieve complete tumor necrosis in the RF group than in the other 2 groups (P < .01). The local tumor progression rate was lowest in the RF group (vs the conventional PEI group, P = .012; vs the higher-dose PEI group, P = .037). The overall survival rate was highest in the RF group (vs the conventional PEI group, P = .014; vs the higher-dose PEI group, P = .023). The cancer-free survival rate was highest in the RF group (vs the conventional PEI group, P = .019; vs the higher-dose PEI group, P = .024). Multivariate analysis determined that tumor size, tumor differentiation, and the method of treatment (RF vs both methods of PEI) were significant factors in relation to local tumor progression, overall survival, and cancer-free survival. CONCLUSIONS: The results show that RF ablation yielded better clinical outcomes than conventional and higher-dose PEI in treating HCC 4 cm or less.     

Radiofrequency ablation of hepatocellular carcinoma in cirrhotic patients

BACKGROUND/AIMS: Radiofrequency ablation is useful for local destruction of primary and secondary hepatic tumors. However there is little information about long-term outcome for patients with hepatocellular carcinoma and cirrhosis. The aims of this study included the analysis of efficacy in local control of tumors, patterns of recurrence and survival rate related to severity of cirrhosis and tumor features. METHODOLOGY: From January 1998 to January 2001 we ablated 65 hepatocellular carcinomas in 53 patients with cirrhosis. Cirrhosis was related to HCV, HBV and alcohol intake in 32, 4 and 17 patients, respectively. According to Child-Pugh classification 24 and 29 patients belong to A and B class, respectively. Patients in Child-Pugh C class were excluded from the study. The mean diameter of lesions was 4 cm (range: 1-7 cm). In all cases radiofrequency ablation was performed with the percutaneous approach under ultrasound guidance. Treatment efficacy was estimated with dual phase computed tomography and alpha-fetoprotein dosage. RESULTS: Complete necrosis rate after first treatment was 90.9, 74.4 and 36.4% in hepatocellular carcinoma smaller than 3 cm, between 3 and 5 cm and larger than 5 cm, respectively (p = 0.01). After multiple treatment complete necrosis was achieved in 100, 93 and 63.6% (p = 0.01). The mean number of treatments was 1.5 (range: 1-4) per patients. Four lesions of 58 (6.8%) developed local recurrence during a mean follow-up of 18 months. No local recurrence was observed in tumors smaller than 4 cm. New tumors were observed in 15 patients (28.3%). There were no treatment-related deaths and 11 patients (20.7%) suffered minor complications. The survival rate of patients after treatment was 87, 63 and 45% at 12, 24 and 36 months, respectively. Survival was significantly related to Child-Pugh class (p = 0.01). CONCLUSIONS: Radiofrequency ablation is a safe and effective treatment of hepatocellular carcinoma smaller than 5 cm with complete necrosis in most lesions. No local recurrences were observed in lesions smaller than 4 cm. After 3 years survival was 83% in Child-Pugh A cirrhotic patients and 31% in Child-Pugh B patients.     

Gold‐Tip Electrodes—A New “Deep Lesion” Technology for Catheter Ablation? In Vitro Comparison of a Gold Alloy Versus Platinum–Iridium Tip Electrode Ablation Catheter

Gold-tip electrodes. Radiofrequency (RF) catheter ablation is widely used to induce focal myocardial necrosis using the effect of resistive heating through high-frequency current delivery. It is current standard to limit the target tissue-electrode interface temperature to a maximum of 60-70 degrees C to avoid char formation. Gold (Au) exhibits a thermal conductivity of nearly four times greater than platinum (Pt-Ir) (3.17 W/cm Kelvin vs 0.716 W/cm Kelvin), it was therefore hypothesized that RF ablation using a gold electrode would create broader and deeper lesions as a result of a better heat conduction from the tissue-electrode interface and additional cooling of the gold electrode by "heat loss" to the intracardiac blood. Both mechanisms would allow applying more RF power to the tissue before the electrode-tissue interface temperature limit is reached. To test this hypothesis, we performed in vitro isolated liver and pig heart investigations comparing lesion depths of a new Au-alloy-tip electrode to standard Pt-Ir electrode material. Mean lesion depth in liver tissue for Pt-Ir was 4.33+/-0.45 mm (n=60) whereas Au electrode was able to achieve significantly deeper lesions (5.86+/-0.37 mm [n=60; P<0.001]). The mean power delivered using Pt-Ir was 6.95+/-2.41 W whereas Au tip electrode delivered 9.64+/-3.78 W indicating a statistically significant difference (P<0.05). In vitro pig heart tissue Au ablation (n=20) increased significantly the lesion depth (Au: 4.85+/-1.01 mm, Pt-Ir: 2.96+/-0.81 mm, n=20; P<0.001). Au tip electrode again applied significantly more power (P<0.001). Gold-tip electrode catheters were able to induce deeper lesions using RF ablation in vitro as compared to Pt-Ir tip electrode material. In liver and in pig heart tissue, the increase in lesion depth was associated with a significant increase in the average power applied with the gold electrode at the same level of electrode-tissue temperature as compared to platinum material.     

EUS-guided radiofrequency ablation in the pancreas: results in a porcine model.

BACKGROUND: Our aim in this study was to investigate the feasibility and safety of performing radiofrequency (RF) ablation in the pancreas with endoscopic ultrasound (EUS). METHODS: RF was applied to normal pancreatic tissue in 13 anesthetized Yorkshire pigs with specially modified 19-gauge needle electrodes (1.0 to 1.5 cm tip). The pancreas was localized with EUS and punctured through a transgastric approach. RF current (285 +/- 120 mA) was delivered for 6 minutes. Diagnostic imaging (EUS and CT) and serum amylase and lipase levels were obtained at baseline, immediately after ablation, and 1 to 14 days after the procedure. Pigs were killed immediately (n = 5), 1 to 2 days after ablation (n = 2), and 2 weeks after the procedure (n = 6). Pathologic examination was performed. RESULTS: Sixteen ablations were performed. During ablation, round hyperechoic foci (diameter to 1.0 cm) gradually surrounded the tip of the electrode. Immediately after the procedure CT demonstrated 1 cm hypodense foci that did not enhance with iodinated contrast. In pigs killed immediately and 1 to 2 days after ablation, pathologic examination showed discrete, well-demarcated spherical foci of coagulation necrosis measuring 8 to 12 mm in diameter surrounded by a 1 to 2 mm rim of hemorrhage. Radiologic-pathologic correlation was within 2 mm. In 4 of 6 (67%) pigs killed on day 14, retraction of the coagulated focus was observed. A 1 to 3 mm fibrotic capsule surrounded the coagulated tissue in the remaining 2 pigs. One pig had mild hyperlipasemia, a focal zone of pancreatitis (<1 cm), and later a pancreatic fluid collection. Biochemical parameters were normal in the remaining pigs. Other complications included three gastric and one intestinal burn caused by improper electrode placement. CONCLUSIONS: EUS-guided RF ablation can be used safely to produce discrete zones of coagulation necrosis in the porcine pancreas. Potential clinical uses of this technology include management of small neuroendocrine tumors and possibly palliation of unresectable pancreatic adenocarcinoma.     

Efficacy of selective transarterial chemoembolization in inducing tumor necrosis in small (<5 cm) hepatocellular carcinomas

Transarterial chemoembolization (TACE) is commonly used as a bridge therapy for patients awaiting liver transplantation (LT) and for downstaging patients initially not meeting the Milan criteria. The primary aim of this study was to analyze whether a difference exists between selective/superselective and lobar TACE in determining tumor necrosis by a pathological analysis of the whole lesion at the time of LT. The secondary aim was to investigate the relationship between the tumor size and the capacity of TACE to induce necrosis. Data were extracted from a prospective database of 67 consecutive patients who underwent LT for hepatocellular carcinoma and cirrhosis from 2003 to 2009 and were treated exclusively with TACE as a bridging (n = 53) or downstaging therapy (n = 14). We identified 122 nodules; 53.3% were treated with selective/superselective TACE. The mean histological necrosis level was 64.7%; complete tumor necrosis was obtained in 42.6% of the nodules. In comparison with lobar TACE, selective/superselective TACE led to significantly higher mean levels of necrosis (75.1% versus 52.8%, P = 0.002) and a higher rate of complete necrosis (53.8% versus 29.8%, P = 0.013). A significant direct relationship was observed between the tumor diameter and the mean tumor necrosis level (59.6% for lesions < 2 cm, 68.4% for lesions of 2.1-3 cm, and 76.2% for lesions > 3 cm). Histological necrosis was maximal for tumors > 3 cm: 91.8% after selective/superselective TACE and 66.5% after lobar procedures. Independent predictors of complete tumor necrosis were selective/superselective TACE (P = 0.049) and the treatment of single nodules (P = 0.008). Repeat sessions were more frequently needed for nodules treated with lobar TACE (31.6% versus 59.3%, P = 0.049). CONCLUSION: Selective/superselective TACE was more successful than lobar procedures in achieving complete histological necrosis, and TACE was more effective in 3- to 5-cm tumors than in smaller ones.     

Radiofrequency ablation of liver tumors: experience with open and percutaneous approach.

BACKGROUND: Radiofrequency ablation (RFA), a thermal coagulation technique, has been used for ablation of primary and secondary liver tumors. METHODS: Over a 24-month period, 41 patients, including 20 with hepatocellular cancer (HCC), 14 with liver metastases from colorectal tumors and 7 with metastases from other tumors, underwent RFA in our institution. Ablation was done using intra-operative (n=27) or percutaneous ultrasonographic (n=14) guidance. A zone of ablation larger than the size of the lesion on CT scan indicated successful RFA. RESULTS: The mean size of lesions was 4.9 cm for HCC and 3.1 cm for metastases. Among 20 patients with HCC, 16 had complete tumor ablation and one had failure of localization. All patients with liver metastases had successful tumor ablation. There was no procedure-related death. Two patients had hemoperitoneum and one experienced skin burn. During a median follow up of 16 months, five patients with HCC and two with colorectal metastases died. One patient had tumor recurrence at the ablation site and two developed fresh solitary metastatic lesions; all three are disease-free after repeat ablation treatment. CONCLUSIONS: RFA is a safe and promising technique for the treatment of non-resectable HCC and liver metastases, in the short term.     

Radiofrequency ablation for treatment of hepatocellular carcinoma with cirrhosis

BACKGROUND/AIMS: The majority of hepatocellular carcinoma patients with cirrhosis are not candidates for surgical resection, and local thermal therapy producing destruction of cancer cells was one of the ideal options for treatment. Heat from radiofrequency ablation is generated through agitation caused by an alternating electrical current. The heat of radiofrequency energy results in local cell coagulation and causes cellular ablation necrosis of tumor tissue. METHODOLOGY: Eighteen cases of hepatocellular carcinoma were treated with radiofrequency ablation in our institute. We used a RFA 2000 generator (Boston Scientific Co, USA) with LeVeen needle with the maximum diameter of 3.5 cm when the array electrodes were fanned out. The indications for this method included; i) normal prothrombin profile, ii) no ascites, iii) tumor can be detected and approached by ultrasound, iv) tumor cannot be resected or patient is not willing to take the operation. RESULTS: No specific complication was noted during or after the procedure. Only two cases needed more analgesics after the procedure. One case was found with burning of the stomach serosa proved by laparoscopic examination, in which radiofrequency ablation was performed to the tumor located in the left lobe of the segment 3. Impedance could not raise up completely in two cases with larger size tumor more than 5 cm. The decreased levels of alpha-fetoprotein were significant (P = 0.005) after radiofrequency ablation treatment. Residual tumor was found in four cases (20%) in the follow-up abdominal computed tomography scan. CONCLUSIONS: Radiofrequency ablation resulted in a higher rate of complete necrosis of tumor tissue and the complication rate was low as well. Therefore, we believed that radiofrequency ablation is an ideal treatment modality for most liver tumors, which cannot tolerate the conventional surgical procedures.     

Histopathology of intraoperatively induced linear radiofrequency ablation lesions in patients with chronic atrial fibrillation.

AIMS: Radiofrequency (RF) energy has been extensively used in ablation of arrhythmia but so far no analysis of morphological effects in human left atria has been conducted. METHODS AND RESULTS: We studied 59 ablation lesions from seven patients who died 2 to 22 days after open heart surgery plus intraoperative cooled-tip RF ablation to treat permanent atrial fibrillation (AF) (mean 4, 1-11 years). The ablation area was studied by macroscopy and histological analysis. RF ablation produced clearly delineated coagulation necrosis (up to a depth of 5.5 mm) bordered by an irregular zone of incomplete necrosis and fresh bleeding even 22 days post-operatively. No superficial charring, thrombotic deposition, or perforation was documented. Endocardium and subendocardium displayed oedematic loosening and microfragmentation of connective tissue fibres. Early after ablation (2-6 days), interfibrillar disseminated bleeding and necrosis without tissue removal response were found. Later after ablation (21, 22 days), mild inflammatory reaction and granulation tissue appeared. Twenty-five per cent of all studied lesions, especially in the thick region in between left pulmonary veins and mitral annulus (left atrial isthmus) (86%), were non-transmural. Nerve fibres with different degrees of thermal injury were detected in the pulmonary vein ostial region. CONCLUSION: Intraoperative cooled-tip ablation in AF resulted in coagulation necrosis of endocardium, subendocardium, and the atrial myocardial layer to a depth of 5.5 mm bordered by an irregular zone of incomplete thermal damage. Transmurality of the lesions could only be found in 75% of intraoperatively applied lesions.     

Case Report: Severe Skin Burn at the Site of the Indifferent Electrode After Radiofrequency Catheter Ablation of Typical Atrial Flutter

Although radiofrequency (RF) catheter ablation has been shown to be an effective treatment strategy in patients with supraventricular tachycardia, RF ablation may lead to potentially serious complications. We describe a case of a 65-year old man who was transferred for catheter ablation of typical atrial flutter. 21 RF applications (mean energy: 81±9 watts) were applied in the temperature-controlled mode (70[emsp4 ]°C) between a 8-mm tip electrode and an indifferent electrode using a high-power RF generator (100 watts) until bi-directional atrial isthmus block was achieved. After the procedure, a third-degree skin burn (10×2[emsp4 ]cm) was observed at the lateral edge of the adhesive indifferent electrode whereas the medial edge of the electrode was not fully attached to the skin surface. This case is one out of 1128 ablation procedures (0.09%) at our institution using a high-power RF generator. The present study demonstrates a severe skin burn induced by mal-attachment of an indifferent electrode during RF ablation. Long RF energy application times, high-power settings, and heavy sedation may have contributed to the observed severity of skin damage.     

Percutaneous radiofrequency ablation of hepatocellular adenoma: Initial experience in 10 patients

Background and Aim:  The purpose of this study was to assess the therapeutic efficacy and safety of percutaneous radiofrequency (RF) ablation for hepatocellular adenoma.
Methods:  We performed percutaneous RF ablation in 10 patients with pathologically proven hepatocellular adenomas. Eight patients were asymptomatic and two patients had a recurrent tumor after surgical resection. The size of the tumors was 2.25 ± 0.76 cm (range: 1.5–4.5 cm) in the largest diameter. All ablation procedures were percutaneously performed with an internally cooled RF electrode system under ultrasound (US) guidance. We evaluated the therapeutic efficacy and safety of the procedure by clinical follow-up data with regular follow-up computed tomography (CT) for 2–35 months (mean, 17.5 months).
Results:  All patients well tolerated percutaneous RF ablation procedure without any incident. Contrast-enhanced CT ( n  = 7) or contrast-enhanced US ( n  = 3) obtained immediately (<24 h) after the procedure revealed complete ablation of the tumor in all cases. There was no case of local tumor progression or new recurrence during the follow-up period. We found neither procedure-related mortality nor major complication requiring specific treatment.
Conclusion:  Percutaneous RF ablation of hepatocellular adenoma without overt complication can be a new potential alternative to close imaging follow-up or elective surgery.     

Transmembraneous Irrigation of Multipolar Radiofrequency Ablation Catheters: Induction of Linear Lesions Encircling the Pulmonary Vein Ostium Without the Risk of Coagulum Formation?

INTRODUCTION: Pulmonary vein (PV) isolation for the curative treatment of atrial fibrillation using conventional radiofrequency ablation (RF) catheters with the point by point technique is time consuming and carries a remaining risk for thrombembolic complications. AIMS OF THE STUDY: Aim of the present in vivo study was to evaluate feasibility and safety of a novel multipolar irrigated ablation catheter designed to create contiguous lesions encircling the PV ostium in a single ablation position. METHODS: The entire ablation section (tripolar, length of each electrode 22 mm, interelectrode distance 2 mm, helix radius: 9 and 10 mm) of the 7F RF catheter (Encirclr, Medtronic, MN, USA) was covered by a porous membrane (pore size 30 micron) providing continuous irrigation. The helical formed catheter was used in two different experimental settings. Initially, a thigh muscle preparation has been performed in 7 anesthetized sheep in order to evaluate the development of lesions at different power level (40-80 W) and RF duration (30-90 sec). The ablation catheter was placed at the surface of the thigh muscle in a perpendicular position (0.1 N contact pressure) and perfused with heparinized blood (250 ml/min, 37C degrees ). Irrigation was provided with a flow rate of 10 ml/min. The resulted lesion morphology was evaluated with regard to coagulum or crater formation and lesion depth and diameter. Subsequently in 9 anesthetized sheep intracardiac ablation has been achieved with 50 W and an irrigation flow of 10 ml/min. Transseptal puncture and RF ablations were guided using fluoroscopy and intracardiac echocardiography (ICE, Acuson, USA). Endpoint of the intracardiac RF applications was the reduction of local electrogram amplitude >50%. RF applications were achieved at both atrial appendages and in the orifices of the coronary sinus (CS), the vena cava inferior (VCI) and PV. Following RF ablation all animals were sacrificed and following in vivo staining (2% TTC) macroscopically and histologically investigations of the lesions were performed. RESULTS: At the thigh muscle preparation 57 RF applications have been performed. The lesion depth was homogeneous without gaps between the ablation electrodes. There was a significant increase comparing 30 with 90 sec of RF duration for 40, 50 and 60 W applications respectively: 40 W: 1.1 +/- 0.4 vs. 3.6 +/- 0.5; 50 W: 1.2 +/- 0.3 vs. 4.6 +/- 0.4 mm and 60 W: 2.6 +/- 0.6 vs. 4.8 +/- 0.5 mm. All applications with 80 W (n = 3) had to be terminated due to immediate increase of impedance >150 omega. Late impedance rises (>60 sec) without occurrence of coagulum formation have been observed in 1 out of 4 RF applications with 60 W.A total of 85 RF applications could be achieved intracardiacally in the right atrium (right atrial appendage n = 18, ostium of the coronary sinus n = 12, ostium of the inferior caval vein: n = 12) and in the left atrium (left atrial appendage: n = 15, ostium of the PV: n = 28). ICE guided positioning of the catheter and showed during all applications no coagulum formation at the electrode or impedance rise (>150 Omega). Reduction of local electrograms (>50%) were observed following 48 out 85 (56%) RF applications. The lesions showed a homogeneous depth of 4 +/- 2 mm and a width 5 +/- 2 mm at the surface. No charring or crater formation could be observed in any of the lesions. CONCLUSIONS: In the present in vivo studies it could be demonstrated that long irrigated ablation electrodes induce continuous lesions without the risk of thrombus formation at the electrode. Increase of RF duration from 30 to 90 seconds with power setting of 40-60 W, respectively, created deeper lesions without the risk of thrombus formation. Thus, the helical formed irrigated ablation catheter appears to be appropriate for simplified PV isolation.     

Radiofrequency Ablation of Atrial Insertion of Left-Sided Accessory Pathways Guided by the "W Sign"

AP Ablation and the "W Sign." introduction: The aim of this study was to evaluate the efficacy of radiofrequency (RF) ablation of the atrial insertion of left-sided aceessory pathways with guidance by a specific morphologic characteristic of the local electrogram, which we call the "W sign." This represents the shortest local atrioventricular (AV) interval during sinus rhythm in patients with manifest preexcitation or the shortest local VA interval during AV reciprocating tachycardia and/or ventricular pacing in patients with concealed accessory pathways.
Methods and Results: The transseptal technique was used in 31 patients (18 men, 13 women; aged 32 ± 13 years), and RF ablation of 33 accessory pathways (26 manifest and 7 concealed) was attempted. Patients presented with palpitations (n = 16), presyncope (n = 10), or syncope (n = 5). The clinical arrhythmia was AV reciprocating tachycardia (n = 24) or atrial fibrillation (n = 7). In 21 patients (68%) electrophysiologic study and RF ablation were performed at a single session. Accessory pathways were left posteroseptal (n = 5) or left free wall (n = 28). The "W sign," formed from merging of the local atrial and ventricular electrograms, was identified at all successful sites prior to ablation. Ablation was successful in all patients. A median of 7 RF lesions were delivered per patient. The fluoroscopy time was 76 ± 48 minutes; total procedure time was 5.4 ± 1.9 hours. No significant complications occurred. Early recurrence (≤ 24 hours) occurred in I patient; during 6 ± 4 months, accessory pathway conduction recurred in another patient.
Conclusion: We conclude that RF ablation of the atrial insertion of left accessory pathways can be very successful when guided by the "W sign."     

Importance of right and left atrial dilation and linear ablation for perpetuation of sustained atrial fibrillation

INTRODUCTION: Atrial dilation associated with increasing atrial pressure plays an apparent role in the development of atrial fibrillation (AF). We characterized a new model of separate and biatrial dilation in the Langendorff-perfused rabbit heart. The aim of this study was to examine if sustained AF in this model (1) would be inducible by separate right atrial (RA) and left atrial (LA) dilation; (2) would be reproducibly inducible at the same pressure level; and (3) could be suppressed by RA, LA, or biatrial ablation. METHODS AND RESULTS: Intra-atrial pressure was increased stepwise in the RA (n = 13), LA (n = 12), or both atria (n = 25) until sustained AF could be induced or a pressure of 20 cm H2O was reached. The stimulation protocol was repeated once in RA and LA dilation (n = 9) and three times in biatrial dilation (n = 7). Then, RA orifices (superior and inferior caval veins, tricuspid valve annulus, and foramen ovale) or LA orifices (pulmonary veins, mitral valve annulus, and foramen ovale) were connected by radiofrequency (RF) lesions. Sustained AF was rendered inducible in 100% of hearts with biatrial dilation, but in only 92% of hearts with RA dilation and 67% with LA dilation. Inducibility of sustained AF was reproducible. Under biatrial dilation, not RA ablation (0/10 hearts; P = NS) but LA ablation (4/11 hearts; P < 0.05) and biatrial ablation (16/21; P < 0.01) reduced the inducibility of sustained AF. CONCLUSION: The inducibility of sustained AF due to increased intra-atrial pressure differs between the RA and LA. LA and biatrial lesions, not RA RF lesions, reduce the ability to perpetuate sustained AF.     

Percutaneous ethanol injection, radiofrequency and their combination in treatment of hepatocellular carcinoma

AIM: To evaluate the therapeutic effect and the indication of percutaneous ethanol injection (PEI), radiofrequency ablation (RFA) and their combination in treatment of hepatocellular carcinoma (HCC). METHODS: Two hundred and fifty-five patients with HCC received treatment of PEI, RFA or their combination. Groupl (< 3 cm in diameter, n=85) was treated with PEI, group2(< 3 cm in diameter, n=153) with RFA. Group3 (>3 cm in diameter, n=86) was divided into two groups. Group 3a (n=34) was treated with RFA, while group 3b (n=52) was treated with RFA for 2 wk after transcatheter arterial chemoembolization or PEI. Contrast-enhanced sonography was performed for 61 patients before and after RFA. Liver function and serum alpha-fetoprotein (AFP) were measured for all patients. Changes of the lesions on ultrasound and contrast-enhanced CT/MRI were evaluated for assessing the therapeutic responses. The 1-, 2-, 3- and 5-year survival rates were recorded after treatment. RESULTS: In group 1, the complete necrosis rate of lesions after 1 mo was 77.6% (66/85). The level of AFP declined conspicuously after 1 mo. The 1-, 2-, 3- and 5-year survival rate after treatment was 80.0% (52/65), 60.4% (32/53), 52.5% (21/40) and 33.3% (7/21), respectively. In group 2, the complete necrosis rate of lesions after 1 moh was 92.2% (141/153). The level of AFP decreased conspicuously after 1 mo. The 1-, 2-, 3- and 5-year survival rate after treatment was 94.6% (88/93), 73.2% (52/71), 63.5% (33/52) and 46.4% (13/28), respectively. In group 3a, the complete necrosis rate of lesions after 1 mo was 23.5% (8/34). AFP dropped down to the normal level in only one patient after 1 mo. The 1-, 2- and 3-year survival rate after treatment was 47.6% (10/21), 42.9% (6/14) and 27.3% (3/11), respectively. Only one patient was still alive after 5 years. In group 3b, the complete necrosis rate of lesions after 1 mo was 57.7% (30/52). The level of AFP decreased after 1 mo. The 1-, 2-, 3- and 5-year survival rate after treatment was 68.6% (24/35), 46.2% (12/26), 36.8% (7/19) and 27.3% (3/11), respectively. CONCLUSION: The therapeutic effect of RFA on small HCC is better than that of PEL Small HCC is the optimal indication of RFA. For recurrent HCC (diameter>3 cm), the combined treatment of RFA and PEI/ACE should be used.     

Avoiding microbubbles formation during radiofrequency left atrial ablation versus continuous microbubbles formation and standard radiofrequency ablation protocols: comparison of energy profiles and chronic lesion characteristics

BACKGROUND: Radiofrequency (RF) energy parameters and chronic lesion characteristics associated with the microbubbles formation have not been yet fully elucidated. OBJECTIVES: The objective of this study was to compare the energy profiles and chronic lesion characteristics associated with RF ablation of the pulmonary vein antrum using three different ablation protocols: (1) avoiding microbubbles; (2) continuous microbubble formation; (3) temperature-guided ablation. METHODS: A 4-mm tip ablation catheter was used for creating RF ablation lesions in 15 adult mongrel dogs. All ablation lesions were created at the posterior aspect of the PV antrum in each animal. Avoiding microbubbles (group 1, n = 5 dogs, 23 lesions), continuous microbubble formation (group 2, n = 5 dogs, 22 lesions), and temperature-guided (group 3, n = 5 dogs, 19 lesions, target temperature 60 degrees C/power limit 50 W) ablation lesions were analyzed. RESULTS: Group 1 showed significantly lower power (19 +/- 8.6 W), lower temperature (50 +/- 4.8 degrees C), higher efficiency-of-heating index (2.9 +/- 0.8 degrees C/W), and lower impedance (109 +/- 24.4 Omega) than groups 2 (38 +/- 8.4 W; 63 +/- 10 degrees C; 1.8 +/- 0.8 degrees C/W; 148 +/- 34.4 Omega) and 3 (44 +/- 12 W; 57 +/- 2.4 degrees C; 1.4 +/- 0.5 degrees C/W; 139 +/- 23.1 Omega) (P < 0.001 vs groups 2 and 3). During ablation, no significant events were detected in group 1, but 11 cases of audible pop, 11 cases of catheter tip charring, and 1 case of fatal myocardial perforation were observed in groups 2 and 3. Transmural lesions were more frequently created in group 1. CONCLUSION: RF energy delivery applying "avoiding microbubbles" protocol seems to be associated with higher degree of safety and efficacy when compared to temperature-guided and continuous microbubble-formation ablation protocols.     

Changes in local wall thickness correlate with pathologic lesion size following radiofrequency catheter ablation: an intracardiac echocardiographic imaging study

INTRODUCTION: High-resolution intracardiac echocardiographic (ICE) imaging can accurately assess wall thickness during radiofrequency (RF) catheter ablation procedures. This study investigated the correlation of changes in wall thickness at the ablation site with pathologic lesion size. METHODS AND RESULTS: ICE image-guided 31 RF applications (30-50 W, up to 120 sec) were performed in five anesthetized closed chest swine (n = 5, body weight 35-60 kg). Twenty-four lesions were delivered in the right and left atria with standard RF; seven lesions were delivered in the left ventricle (LV) with irrigated (30-40 ml/min) RF. Wall thickness and tissue echo density measured by ICE imaging (pre- and 1-minute post-RF delivery) with increased focal echo density following RF deployment in the atria (4.5 +/- 1.5 vs 2.3 +/- 1.0 mm pre-RF) and the LV (9.8 +/- 2.3 vs 6.8 +/- 2.2 mm pre-RF; P < 0.01). The observed changes in wall thickness (DeltaWT) following ablation in the LV were greater than in the atria (3.0 +/- 1.4 vs 2.2 +/- 1.2 mm; P < 0.05). A significant correlation between DeltaWT and lesion depth (ventricular: r = 0.85, P < 0.05; atrial: r = 0.82, P < 0.01) was demonstrated at all ablation sites. Local wall thickness measured post-RF also significantly correlated with lesion depth (r = 0.89, P < 0.01), especially with that of transmural lesions (r = 0.95, n = 23, P < 0.001) at atrial and LV sites. CONCLUSION: Therapeutic RF ablation results in mural swelling and increased echo density. These changes can be detected by ICE imaging and correlate with pathologic lesion size. ICE imaging may be useful in online quantification of lesion size, especially for transmural lesions during clinical catheter ablation procedures.     

Doxorubicin-eluting bead-enhanced radiofrequency ablation of hepatocellular carcinoma: a pilot clinical study

BACKGROUND/AIMS: Experimental studies have shown synergy between radiofrequency (RF) ablation and adjuvant chemotherapy in animal tumour models. We aimed to assess safety and efficacy of doxorubicin-eluting bead (DEB)-enhanced RF ablation in the treatment of human hepatocellular carcinoma (HCC). METHODS: Twenty patients with single HCC ranging 3.3-7.0cm (mean, 5.0cm+/-1.4) showing evidence of residual viable tumour after standard RF ablation underwent intraarterial DEB administration (50-125mg doxorubicin; mean, 60.2mg+/-21.8). Follow-up period ranged 6-20 months (mean, 12 months+/-5). RESULTS: No major complication occurred. No deterioration of liver function was observed. The volume of treatment-induced necrosis - as measured on imaging - increased from 48.1cm(3)+/-35.7 after RF ablation to 75.5cm(3)+/-52.4 after DEB administration, with an increase of 60.9%+/-39.0. The enhanced effect resulted in confirmed complete response (CR) of the target lesion in 12 (60%) of 20 patients. Incomplete response with persistence of <10% of initial tumour volume was observed in 6 (30%) of 20 patients, and local tumour progression in 2 (10%) of 20. CONCLUSIONS: Intraarterial DEB administration substantially enhances the effect of RF ablation. DEB-enhanced RF ablation is safe and results in a high rate of CR in patients refractory to standard RF treatment.     

Adjuvant percutaneous radiofrequency ablation of feeding artery of hepatocellular carcinoma before treatment

AIM： To evaluate the feasibility and efficacy of percutaneous radiofrequency ablation （RFA） of the feeding artery of hepatocellular carcinoma （HCC） in reducing the blood-flow-induced heat-sink effect of RFA.
METHODS： A total of 154 HCC patients with 177 pathologically confirmed hypervascular lesions participated in the study and were randomly assigned into two groups. Seventy-one patients with 75 HCCs （average tumor size, 4.3 ± 1.1 cm） were included in group A, in which the feeding artery of HCC was identified by color Doppler flow imaging, and were ablated with multiple small overlapping RFA foci [percutaneous ablation of feeding artery （PAA）] before routine RFA treatment of the tumor. Eighty-three patients with 102 HCC （average tumor size, 4.1 ± 1.0 cm） were included in group B, in which the tumors were treated routinely with RFA. Contrast-enhanced computed tomography was used as post-RFA imaging, when patients were followed-up for 1, 3 and 6 mo.
RESULTS： In group A, feeding arteries were blocked in 66 （88%） HCC lesions, and the size of arteries decreased in nine （12%）. The average number of punctures per HCC was 2.76 ± 1.12 in group A, and 3.36 ± 1.60 in group B （P = 0.01）. The tumor necrosis rate at 1 mo post-RFA was 90.67% （68/75 lesions） in group A and 90.20% （92/102 lesions） in group B. HCC recurrence rate at 6 mo post-RFA was 17.33% （13/75） in group A and 31.37% （32/102） in group B （P = 0.04）.
CONCLUSION： PAA blocked effectively the feeding artery of HCC. Combination of PAA and RFA significantly decreased post-RFA recurrence and provided an alternative treatment for hypervascular HCC.     

Percutaneous ethanol injection, radiofrequency and their combination in treatment of hepatocellular carcinoma

AIM: To evaluate the therapeutic effect and the indication of percutaneous ethanol injection (PEI),radiofrequency ablation (RFA) and their combination in treatment of hepatocellular carcinoma (HCC).METHODS: Two hundred and fifty-five patients with HCC received treatment of PEI, RFA or their combination.Group1 (＜ 3 cm in diameter, n=85) was treated with PEI,group2 (＜ 3 cm in diameter, n=153) with RFA. Group3(＞3 cm in diameter, n=86) was divided into two groups.Group 3a (n=34) was treated with RFA, while group 3b(n=52) was treated with RFA for 2 wk after transcatheter arterial chemoembolization or PEI. Contrast-enhanced sonography was performed for 61 patients before and after RFA. Liver function and serum alpha-fetoprotein (AFP) were measured for all patients. Changes of the lesions on ultrasound and contrast-enhanced CT/MRI were evaluated for assessing the therapeutic responses.The 1-, 2-, 3- and 5-year survival rates were recorded after treatment.RESULTS: In group 1, the complete necrosis rate of lesions after 1 mo was 77.6% (66/85). The level of AFP declined conspicuously after 1 mo. The 1-, 2-, 3- and 5-year survival rate after treatment was 80.0% (52/65),60.4% (32/53), 52.5% (21/40) and 33.3% (7/21),respectively. In group 2, the complete necrosis rate of lesions after 1 moh was 92.2% (141/153). The level of AFP decreased conspicuously after 1 mo. The 1-, 2-,3- and 5-year survival rate after treatment was 94.6%(88/93), 73.2% (52/71), 63.5% (33/52) and 46.4%(13/28), respectively. In group 3a, the complete necrosis rate of lesions after 1 mo was 23.5% (8/34). AFP dropped down to the normal level in only one patient after 1 mo. The 1-, 2- and 3-year survival rate after treatment was 47.6% (10/21), 42.9% (6/14) and 27.3%(3/11), respectively. Only one patient was still alive after 5 years. In group 3b, the complete necrosis rate of lesions after 1 mo was 57.7% (30/52). The level of AFP decreased after 1 mo. The 1-, 2-, 3- and 5-year survival rate after treatment was 68.6% (24/35), 46.2% (12/26),36.8% (7/19) and 27.3% (3/11), respectively.CONCLUSION: The therapeutic effect of RFA on small HCC is better than that of PEI. Small HCC is the optimal indication of RFA. For recurrent HCC (diameter＞3 cm),the combined treatment of RFA and PEI/ACE should be used.