Hepatic Radiofrequency Ablation Research Articles

Comparison of Internally Cooled Wet Electrode and Hepatic Vascular Inflow Occlusion Method for Hepatic Radiofrequency Ablation

Background/AimsVarious strategies to expand the ablation zone have been attempted using hepatic radiofrequency ablation (RFA). The optimal strategy, however, is unknown. We compared hepatic RFA with an internally cooled wet (ICW) electrode and vascular inflow occlusion.MethodsEight dogs were assigned to one of three groups: only RFA using an internally cooled electrode (group A), RFA using an ICW electrode (group B), and RFA using an internally cooled electrode with the Pringle maneuver (group C). The ablation zone diameters were measured on the gross specimens, and the volume of the ablation zone was calculated.ResultsThe ablation zone volume was greatest in group B (1.82±1.23 cm3), followed by group C (1.22±0.47 cm3), and then group A (0.48±0.33 cm3). The volumes for group B were significantly larger than the volumes for group A (p=0.030). There was no significant difference in the volumes between groups A and C (p=0.079) and between groups B and C (p=0.827).ConclusionsBoth the usage of an ICW electrode and hepatic vascular occlusion effectively expanded the ablation zone. The use of an ICW electrode induced a larger ablation zone with easy handling compared with using hepatic vascular occlusion, although this difference was not statistically significant.

Determining a minimal safe distance to prevent thermal injury to intrahepatic bile ducts in radiofrequency ablation of the liver: A study in dogs

Purpose: To determine a minimal safe distance between the radiofrequency ablation (RFA) electrode tip and major intrahepatic bile ducts to prevent thermal injury during hepatic RFA in a canine model.Materials and methods: Forty healthy mongrel dogs were randomised equally into four groups based on the distance between the electrode and large intrahepatic bile ducts during RFA of the liver, as follows: 1.0–2.9 mm, 3.0–4.9 mm, 5.0–7.9 mm, or 8.0–10.0 mm. The RFA electrodes were opened uniformly at 2 cm. During RFA, energy was sequentially raised, starting at 5 W and increasing by 5 W increments every minute to a maximum of 95 W. Animals were monitored for a maximum of 14 days post-RFA for complications and by bilirubin testing, after which they were euthanised and their livers were surgically removed for cholangiographic and pathological examination.Results: When the electrodes were less than 5.0 mm from the bile ducts during RFA, either full or partial-thickness bile duct necrosis occurred, leading to a variety of serious complications. In contrast, when the distance was more than 5.0 mm between the RFA electrode and bile ducts, serious complications occurred rarely, with pathological examinations showing either normal bile ducts or vacuolar changes of the biliary ductal epithelium.Conclusion: A minimum safe distance of 5.0 mm between the RFA electrode and intrahepatic bile ducts was effective in preventing serious complications secondary to bile duct injury in a canine model.

Treatment of colorectal liver metastasis: Comparison of radiofrequency ablation and hepatic resection.

637 Background: Hepatic resection is the mainstay of management for colorectal liver metastases. But, the treatment for colorectal liver metastases requires a multidisciplinary therapeutic strategy. The aim of this study was to compare recurrence and survival rates for patients treated with hepatic resection or radiofrequency ablation (RFA) for colorectal liver metastases. Methods: Between July 2002 and September 2010, 52 patients underwent hepatic resection and 58 underwent RFA for synchronous or metachronous colorectal liver metastases. A retrospective analysis was performed. Patients with extrahepatic metastases were excluded. Results: The two groups had similar mean age, comorbid medical conditions, primary disease stage, and number of tumors. Preoperative median serum carcinoembryonic antigen (CEA) level was significantly higher in the resection group (13.8 ng/mL vs. 3.1 ng/mL; p = 0.001). Median diameter of main tumors was significantly greater in resection group (4.1 cm vs. 2.0 cm; p = 0.002). Recurrence rate after treatment was 46.2% (24/52) in the resection group and 70.7% (41/58) in the RFA group. Marginal recurrence after resection or RFA was observed in 7.6% (4/52) and 46.6% (27/58), respectively (p = 0.003). Median recurrence free survival (28.0 vs. 12.0 months; p = 0.007) and median overall survival (43.0 vs. 26.0 months; p = 0.023) were significantly longer in the resection group. Conclusions: Hepatic resection is the treatment of choice for colorectal liver metastases. RFA for colorectal liver metastases was associated with higher marginal recurrence rate and shorter recurrence free and overall survival.

Gallbladder Needle Decompression During Radiofrequency Ablation of an Adjacent Liver Tumour

Gallbladder perforation with bile leak can result from thermal injury during radiofrequency ablation of liver tumours. Two case studies demonstrate a technique for preventing gallbladder injury to the peritoneal surface of a distended gallbladder adjacent to the anticipated hepatic ablation zone. The use of percutaneous gallbladder needle decompression can safely separate or retract the peritoneal surface of the gallbladder from a contiguous hepatic radiofrequency ablation zone.

CT-based temperature monitoring during hepatic RF ablation: Feasibility in an animal model

Purpose: The aim of this paper was to establish non-invasive CT-based temperature monitoring during hepatic radiofrequency (RF) ablation in an ex vivo porcine model followed by transfer of the technique into a feasibility in vivo experiment.Materials and methods: Bipolar RF ablations were performed in 10 specimens of porcine liver. Parallel to the needle-shaped RF applicator three optical temperature probes were inserted into the liver specimens at fixed distances of 5, 10 and 15 mm from the RF probe. During energy application (20 W) unenhanced sequential MSCT scans were acquired using the following scan protocol: 140 kV tube voltage, 300 mAs/rotation tube current time product, collimation 24 × 1.2 mm, rotation time 0.5 s. Axial image data was reconstructed using a soft tissue convolution kernel. Temperature data was recorded during every CT scan. Using a circular 0.5 cm2 region of interest local CT values were measured at the tips of the temperature probes and matched with the measured temperatures. Regression analysis was performed to analyse the relationship between local temperatures and CT values for each temperature probe position. Furthermore, the same experimental design was used in four anaesthetised female pigs in order to investigate the potential of this technique for an in vivo application.Results: A negative correlation was found for the relationship between temperature and CT value. Regression coefficients were −0.44 (5 mm), −0.35 (10 mm) and −0.37 (15 mm) for ex vivo data. Analysis of in vivo experiments showed regression coefficients between −0.025 and −0.434.Conclusion: Multislice computed tomography is able to depict temperature changes in liver tissue during RFA.

大腸癌肝転移に対する肝切除とラジオ波焼灼療法の局所制御能の比較

大腸癌肝転移に対する肝切除とラジオ波焼灼療法の局所制御能の比較

Effect of interval between transcatheter hepatic arterial embolization and radiofrequency ablation on ablated lesion size in a swine model

The aim of the study was to clarify the effect of the interval between transcatheter hepatic arterial embolization (TAE) with Lipiodol plus gelatin sponge particles and radiofrequency (RF) ablation on the extent of ablation. Eight healthy swine were divided into four groups: RF ablation (ablation only), RF ablation immediately after TAE (immediate ablation), RF ablation 3 days after TAE (3-day ablation), and RF ablation 6 days after TAE (6-day ablation). Five ablated lesions were created in each swine (10 per group). A 2-cm expandable LeVeen needle electrode was used for RF ablation. Ablated lesions are composed of an outer reddish zone and an inner whitish zone. The average longest length of the major, intermediate, and minor axes and the volume in the immediate ablation, 3-day ablation, and 6-day ablation groups were significant longer and greater (1.52 and 1.52, 1.46 and 1.50, and 1.37 and 1.35 times greater in the red zone and the whitish area, respectively) than those in the ablation-only group (P < 0.05/3). Accumulation of Lipiodol was still noted in the hepatic sinusoids in the 3-day and 6-day ablation groups. RF ablation delayed to 6 days following TAE produced larger ablation volumes than did RF ablation alone.

Diaphragmatic injury after radiofrequency ablation for the liver abutting the diaphragm in a rabbit model

Objective To assess the pathological changes and outcome of diaphragmatic injury after radiofrequency ablation (RFA) for the liver abutting the diaphragm in order to provide a theoretical support of percutanous RFA for hepatocellular carcinoma abutting the diaphragm. Methods The animal models of diaphragmatic injury were made by open surgery RFA for the liver abutting the diaphragm in 10 New Zealand rabbits. Helical enhanced computed tomography (CT) was performed one week and 4 weeks after RFA. The 10 rabbits were killed immediately after the second enhanced CT, and all diaphragmatic lesions underwent gross and histologic examinations. Results Immediately after RFA, the diaphragmatic lesions were gray with an outer pale rim, and no diaphragmatic perforation occurred. The boundaries between lesions and normal area were clear. The area of diaphragmatic lesions was (0.89±0.19) cm2. No major complications, such as diaphragmatic perforation, pleural effusion and ascites, were detected on the postablation CT scan (one week or 4 weeks after the procedure). At gross inspection 4 weeks after RFA, the diaphragmatic lesions became scar-like tissue with hypertrophy of margin. Adhesion formed between the diaphragmatic lesions and the surface of hepatic RFA lesions. The area of scar was (0.73±0.17) cm2. No diaphragmatic perforation was found. On microscopic examination 4 weeks after RFA, the muscle in diaphragmatic lesions disappeared and became fibrous. Diminution, disorder and degeneration of the muscle were found in the outer rim of diaphragmatic lesions, which were replaced by fiber and lymphocyte. Conclusion It is possible to cause full-thickness diaphragmatic injury when adjacent liver is treated with RFA, but it can be repaired by scarring and there is no diaphragmatic perforation. Key words: Radiofrequency ablation; Liver; Diaphragmatic injury; Pathology

Volumetric Arterial Enhancement Fraction Predicts Tumor Recurrence After Hepatic Radiofrequency Ablation of Liver Metastases: Initial Results

The objective of our study was to investigate the diagnostic value of the volumetric arterial enhancement fraction of the liver with color mapping for the early detection of tumor relapse after hepatic radiofrequency ablation (RFA). Fifty-three patients (24 men, 29 women; mean age ± SD, 65 ± 10 years) with a total of 215 liver metastases treated by RFA and a mean postinterventional follow-up period of 20 ± 15 (SD) months were included in this retrospective study. Quantitative arterial enhancement fraction color maps of the whole liver were computed from triple-phase contrast-enhanced MDCT images. Follow-up examinations served as the standard of reference. The diagnostic performance of the arterial enhancement fraction color maps to predict subsequent tumor occurrence before tumor was visible on routine multiphase CT images was evaluated. The mean arterial enhancement fraction of segments that developed metastases (62% ± 23%) was significantly higher than the mean of segments that did not develop metastases (39% ± 20%) (p < 0.0001). Receiver operating characteristic curve analysis revealed a probability of 77% for arterial enhancement fraction values to be higher in case of subsequent metastases as compared with liver parenchyma without tumor recurrence. The arterial enhancement fraction provides incremental value in the imaging surveillance for liver metastases after RFA. Arterial enhancement fraction color maps may be suited to predict tumor recurrence earlier than routine assessment using contrast-enhanced MDCT.

Safety and reliability of hepatic radiofrequency ablation near the inferior vena cava: An experimental study

Purpose: The heat-sink effect produced by rapid blood flow through large vessels (diameter (D) ≥ 5 mm) is an important factor that influences ablation zone size after radiofrequency ablation (RFA). Currently, however, the interactions between hepatic RFA lesions and large vessels are not well understood. The purpose of this study was to examine the effects of RFA lesions occurring near large vessels (D ≥ 5 mm) in the canine liver.Materials and methods: Thirty healthy adult mongrel dogs were used, with 15 dogs randomly assigned to groups I and II. In group I, the closest distance from the tip of the RFA electrode to the large vessel (D ≥ 5 mm) was more than 20 mm; in group II, this distance to the wall of the inferior vena cava (IVC) was no more than 5 mm. RFA was performed on the liver of each dog according to standard procedures. The blood flow velocity of the IVC, the computerised tomography (CT), the pathological characteristics of the RFA lesions and procedure-related complications were examined.Results: No death or complications occurred in any dogs. Vascular walls were not affected, except for when the tips of the electrode stuck to the IVC. The coagulative necrosis region was decreased, and its shape was fusiform close to the IVC. Some normal hepatic cells were found in the necrotic region near the IVC.Conclusions: It is both safe and feasible to perform RFA near the IVC. The shape and size of the coagulation zone should be considered when electrodes are placed in this area. Near the IVC, the size of the coagulation zone was decreased, and it was incompletely formed.

Dual-Energy Computed Tomography to Assess Tumor Response to Hepatic Radiofrequency Ablation

to determine the value of dual-energy (DE) scanning with virtual noncontrast (VNC) images and iodine maps in the evaluation of therapeutic response to radiofrequency ablation (RFA) for hepatic tumors. a total of 75 patients with hepatic tumors and who underwent DE computed tomography (CT) after RFA, were enrolled in this study. Our DE CT protocol included precontrast, arterial, and portal phase scans. VNC images and iodine maps were created from 80 to 140 kVp images during the arterial and portal phases. VNC images were then compared with true, noncontrast (TNC) images, and iodine maps were compared with linearly blended images, both qualitatively and quantitatively. For the former comparison, image quality and acceptability of the VNC images as a replacement for TNC images were both rated. The CT numbers of the hepatic parenchyma, ablation zone, and image noise were measured. For the latter comparison, lesion conspicuity of the ablation zone and the additional benefit of integrating the iodine map into the routine protocol, were assessed. Contrast-to-noise ratios (CNR) of the ablation zone-to-liver and aorta-to-liver as well as the CT number differences between the center and the periphery of the ablation zone were calculated. The image quality of the VNC images was rated as good (mean grading score, 1.88) and the level of acceptance was 90% (68/75). The mean CT numbers of the hepatic parenchyma and ablation zone did not differ significantly between the TNC and the VNC images (P > 0.05). The lesion conspicuity of the ablation zone was rated as excellent or good in 97% of the iodine map (73/75), and the additional benefits of the iodine maps were positively rated as better to the same (mean 1.5). The CNR of the aorta-to-liver parenchyma was significantly higher on the iodine map (P = 0.002), and the CT number differences between the center and the periphery of the ablation zone were significantly lower on the iodine map (P < 0.001). with DE CT scanning, VNC images can be an alternative to TNC images for evaluating the ablation zone after RFA in patients who had no a previous transcatheter arterial chemoembolization history. The iodine map improves the conspicuity of the ablation zone more than linearly blended images because of its excellent internal homogeneity and sharp ablative margin. Higher lesion-to-liver CNR on an iodine map than on standard images can be helpful for detecting residual tumors.

Radiofrequency ablation of liver tumors: Actual limitations and potential solutions in the future

Over the past decade, radiofrequency ablation (RFA) has evolved into an important therapeutical tool for the treatment of non resectable primary and secondary liver tumors. The clinical benefit of RFA is represented in several clinical studies. They underline the safety and feasibility of this new and modern concept in treating liver tumors. RFA has proven its clinical impact not only in hepatocellular carcinoma (HCC) but also in metastatic disease such as colorectal cancer (CRC). Due to the increasing number of HCC and CRC, RFA might play an even more important role in the future. Therefore, the refinement of RFA technology is as important as the evaluation of data of prospective randomized trials that will help define guidelines for good clinical practice in RFA application in the future. The combination of hepatic resection and RFA extends the feasibility of open surgical procedures in patients with extensive tumors. Adverse effects of RFA such as biliary tract damage, liver failure and local recurrence remain an important task today but overall the long term results of RFA application in treating liver tumors are promising. Incomplete ablation of liver tumors due to insufficient technology of ablation needles, tissue cooling by the neighbouring blood vessels, large tumor masses and ablation of tumors in close vicinity to heat sensitive organs remain difficult tasks for RFA. Future solutions to overcome these limitations of RFA will include refinement of ultrasonographic guidance (accuracy of probe placement), improvements in needle technology (e.g. needles preventing charring) and intraductal cooling techniques.

Heat Shock Protein 70 Expression Following Hepatic Radiofrequency Ablation is Affected by Adjacent Vasculature

Heat shock proteins are a highly conserved family of stress response proteins. Members of the heat shock protein 70 (Hsp70) family prevent protein misfolding and aggregation. Following radiofrequency ablation of unresectable liver tumors an interface appears between the irreversibly damaged and normal liver. The fate of this transition zone is critical and is believed to be responsible for local recurrences. Hsp70 is expressed in response to thermal stress and may influence the fate of cells in this transitional zone. It is also recognized that the presence of large vessels or a perivascular location of tumors also influences the recurrence rate. The aim of this study is to examine the transition zone and observe the effect of local blood flow on ablation morphology and Hsp70 expression. Radiofrequency ablation was performed in 25 rats at various distances from the liver hilum. Tissue was retrieved and analysed at time points 0, 4, 24, 48 h, and 2 wk following treatment. Tissue was analyzed histologically with hematoxylin and eosin staining (H and E,) and immunohistochemically for Hsp70 expression. All rats survived the procedure. H and E staining revealed previously unreported foci of apoptosis at the ablation edge and deep in the normal hepatic parenchyma. Hsp70 was expressed in the transition zone at 4 h and peaked at 24 h. The degree of Hsp70 expression was significantly influenced by the distance from surrounding vasculature. This study reports several previously unreported findings. There is increased apoptosis distal to the ablated zone suggests leakage of radiofrequency (RF) current down blood vessels originating in the ablation zone. The degree of Hsp70 expression in the transition zone correlates with time after treatment and the size and location of any adjacent vasculature. These findings suggest that heat shock proteins may play a role in the ability of damaged cells to recover and survive at the periphery of an ablation zone.

Optimal applicator placement in hepatic radiofrequency ablation on the basis of rare data

In this paper, a numerical procedure to determine an optimal applicator placement for hepatic radiofrequency ablation incorporating uncertain material parameters is presented. The main focus is set on the treatment of subjective and rare data-based information. For this purpose, we employ the theory of fuzzy sets and model uncertain parameters as fuzzy quantities. While fuzzy modelling has been established in structural engineering in the recent past, it is novel in biomedical engineering. Incorporating fuzzy quantities within an optimisation task is basically innovative. In our context, fuzzy modelling allows us to determine an optimal applicator placement that maximises the therapy success under the given uncertainty conditions. The applicability of our method is demonstrated by means of an example case.

Quality Initiatives: Strategies for Anticipating and Reducing Complications and Treatment Failures in Hepatic Radiofrequency Ablation

Radiofrequency (RF) ablation is one of several local treatment strategies that can be used for the destruction of a variety of primary and secondary liver tumors. As experience with RF ablation grows, it becomes increasingly evident that successful ablation requires meticulous technique. In addition, knowledge of potential complications is critical for both the interventionalist and the radiologist, whose postablation interpretation can facilitate identification of complications and treatment failures. Hepatic RF ablation offers significant advantages in that it is less invasive than surgery and carries a low risk of major complications. Successful prevention of complications and treatment failures begins at initial consultation and continues with preablation evaluation of specific patient factors such as coagulation profiles, use of medications, and risk factors for infection. Other predisposing factors include background liver cirrhosis, prior hepatectomy, and portal hypertension. During ablation, careful attention must be given to tumor size, number, and location. For large or multiple ablations, separate ablation sessions can help reduce the prevalence of postablation syndrome, and clustered electrodes and multiple overlapping treatment zones may be used to reduce the risk of treatment failure. It is critical to reevaluate tumors during ablation to determine the best approach and to compensate for changes in size and relative location due to patient positioning. With use of these strategies, hepatic RF ablation can be performed with greater safety, better patient tolerance, and a reduced risk of complications and treatment failures.

S1908 Expression of Kitenin (Kai1 COOH-Terminal Interacting Tetraspanin) in Human Hepatocellular Carcinoma and Its Relation to Tumor Cell Behaviors and Progression

Background and aims: The patient with hepatocellular carcinoma (HCC) diagnosed for the first time was gradually older year by year in spite of the etiology in Japan. Recently the HCC naive patients diagnosed at the age over 80 years old were not rarely found. In that case, the indication of the treatment of patient with HCC was supposed to be difficult due to the liver function and their complication. The aim of this study was to assess the liver function and the prognosis of its treatment of the naive patient with HCC over 80years old. Methods: During 8years(2001~2008), 538patients (203woman and 335man) had been diagnosed for the first time as HCC by ultrasonograpy, computed tomography and magnetic resonance imaging and admitted to our hospital for the treatment. These patients were examined blood test and were performed thepatic resection, percutanous radiofrequency ablation (RFA), transcatheter chemoemblization (TACE) or conservative treatment. We classified the patients in two groups, group A: =80 years old, according to the age diagnosed for the first time, and assessed the clinical data between two groups. Results: Forty subjects (22woman and 18man, HBV:HCV:NBNC=3:28:9) out of 538HCC naive patients (7.4%, HBV:HCV:NBNC=82:383:73) were over 80years old. Women and NBNC cases were more found in the group B (p<0.05). The average age of HCC diagnosis was as follows according to the etiology, 2001; HBV:56.6y.o., HCV:66.9y.o., 2004; HBV:57.6y.o., HCV:68.4y.o., 2008; HBV:61.4y.o., HCV:70.0y.o.. Tumor size was, group A;3.1+/-2.4cm, groupB;3.6+/-2.9cm(n.s.), ICGR15 was, groupA;28.1+/-16.9%, groupB;25.0+/-10.4%(n.s.) and serum ALT levels was group A;56.2+/-39.8cm, groupB;53.9+/-26.6IU/L(n.s.). Statistical significant differentiation was not found between two groups in the Child-Pugh score, Liver staging and over all survival. In 40 subjects over 80years old, the treatment was as follows; Hepatic resection;10, RFA; 2, TACE;22, conservative treatment; 6 and the better over all survival rate was found in the case of hepatic resection or RFA than other treatment (p<0.05). Conclusions: This study showed that, even in the HCC naive patient over 80 years old, the hepatic resection or RFA could be the best indication as the prognosis appears to be good, and that we should provide more intensive care to patients over 80 years old with high serum ALT levels.

S1905 Efficacy of Radiofrequency Ablation for Early Stage Hepatocellular Carcinoma

Background and aims: The patient with hepatocellular carcinoma (HCC) diagnosed for the first time was gradually older year by year in spite of the etiology in Japan. Recently the HCC naive patients diagnosed at the age over 80 years old were not rarely found. In that case, the indication of the treatment of patient with HCC was supposed to be difficult due to the liver function and their complication. The aim of this study was to assess the liver function and the prognosis of its treatment of the naive patient with HCC over 80years old. Methods: During 8years(2001~2008), 538patients (203woman and 335man) had been diagnosed for the first time as HCC by ultrasonograpy, computed tomography and magnetic resonance imaging and admitted to our hospital for the treatment. These patients were examined blood test and were performed thepatic resection, percutanous radiofrequency ablation (RFA), transcatheter chemoemblization (TACE) or conservative treatment. We classified the patients in two groups, group A: =80 years old, according to the age diagnosed for the first time, and assessed the clinical data between two groups. Results: Forty subjects (22woman and 18man, HBV:HCV:NBNC=3:28:9) out of 538HCC naive patients (7.4%, HBV:HCV:NBNC=82:383:73) were over 80years old. Women and NBNC cases were more found in the group B (p<0.05). The average age of HCC diagnosis was as follows according to the etiology, 2001; HBV:56.6y.o., HCV:66.9y.o., 2004; HBV:57.6y.o., HCV:68.4y.o., 2008; HBV:61.4y.o., HCV:70.0y.o.. Tumor size was, group A;3.1+/-2.4cm, groupB;3.6+/-2.9cm(n.s.), ICGR15 was, groupA;28.1+/-16.9%, groupB;25.0+/-10.4%(n.s.) and serum ALT levels was group A;56.2+/-39.8cm, groupB;53.9+/-26.6IU/L(n.s.). Statistical significant differentiation was not found between two groups in the Child-Pugh score, Liver staging and over all survival. In 40 subjects over 80years old, the treatment was as follows; Hepatic resection;10, RFA; 2, TACE;22, conservative treatment; 6 and the better over all survival rate was found in the case of hepatic resection or RFA than other treatment (p<0.05). Conclusions: This study showed that, even in the HCC naive patient over 80 years old, the hepatic resection or RFA could be the best indication as the prognosis appears to be good, and that we should provide more intensive care to patients over 80 years old with high serum ALT levels.

Prospective Analysis of the Pattern and Risk for Severe Vital Sign Changes During Percutaneous Radiofrequency Ablation of the Liver Under Opioid Analgesia

The aims of this study were to evaluate the pattern of vital sign changes and to elucidate significant risk factors for severe cardiovascular inhibition caused by percutaneous hepatic radiofrequency ablation (RFA). A total of 102 patients (male-to-female ratio, 73:29; age range, 35-85 years; mean age, 58.1 years) with 119 malignant hepatic tumors were enrolled and analyzed prospectively. The patients underwent percutaneous RFA with IV infusion of opioid analgesics. Changes in blood pressure (BP) and heart rate (HR) and the occurrence of significant cardiovascular inhibition (BP or HR < 70% of baseline) were monitored during the procedure. Respiratory rate and skin body temperature were recorded before and after the procedure. Whereas the mean BP was elevated (36%, 43/119) or depressed (36%, 43/119) with a similar frequency, the HR was predominantly depressed (56%, 66/119) during the procedure. The BP and HR were stable in only 18% cases (21/119), respectively. The respiratory rate showed no significant change (p = 0.521) after RFA; however, body temperature decreased (p < 0.001) after RFA. Although significant cardiovascular inhibition occurred in 41 cases (35%), all of the cases could be managed successfully and the technical success rate was 100% (119/119). Among the risk factors analyzed, old age (B = -0.003, p = 0.019) was significant for systolic BP depression, and contact of the RFA zone with the central portal vein (B = -0.096, p = 0.014) and female sex (B = -0.078, p = 0.033) were significant risk factors for HR depression as determined by multivariate analysis. Changes in BP and HR, especially bradycardia, are common during percutaneous RFA of hepatic lesions. Significant risk factors for severe cardiovascular inhibition include contact of the RFA zone with the branches of the central portal vein, old age, and female sex.

American Society of Clinical Oncology 2009 Clinical Evidence Review on Radiofrequency Ablation of Hepatic Metastases From Colorectal Cancer

To review the evidence about the efficacy and utility of radiofrequency ablation (RFA) for hepatic metastases from colorectal cancer (CRHM). The American Society of Clinical Oncology (ASCO) convened a panel to conduct and analyze a comprehensive systematic review of the RFA literature from Medline and the Cochrane Collaboration Library. Because data were considered insufficient to form the basis of a practice guideline, ASCO has instead published a clinical evidence review. The evidence is from single-arm, retrospective, and prospective trials. No randomized controlled trials have been included. The following three clinical issues were considered by the panel: the efficacy of surgical hepatic resection versus RFA for resectable tumors; the utility of RFA for unresectable tumors; and RFA approaches (open, laparoscopic, or percutaneous). Evidence suggests that hepatic resection improves overall survival (OS), particularly for patients with resectable tumors without extrahepatic disease. Careful patient and tumor selection is discussed at length in the literature. RFA investigators report a wide variability in the 5-year survival rate (14% to 55%) and local tumor recurrence rate (3.6% to 60%). The reported mortality rate was low (0% to 2%), and the major complications rate was commonly reported to be between 6% and 9%. RFA is currently performed with all three approaches. There is a compelling need for more research to determine the efficacy and utility of RFA to increase local recurrence-free, progression-free, and disease-free survival as well as OS for patients with CRHM. Clinical trials have established that hepatic resection can improve OS for patients with resectable CRHM.

Stress (Tako-Tsubo) Cardiomyopathy Following Radiofrequency Ablation of a Liver Tumor: A Case Report

Stress cardiomyopathy is characterized by transient left ventricular dysfunction occurring in the absence of obstructive coronary disease. It is precipitated by acute emotional or physical stress. We present a case of stress cardiomyopathy which developed during hepatic radiofrequency ablation of hepatocellular carcinoma.