Microwave ablation using 915-MHz and 2.45-GHz systems: what are the differences?

Objectives

This study was conducted to evaluate differences between 915-MHz and 2.45-GHz microwave ablation (MWA) systems in the ablation of hepatic tumours.

Methods

A retrospective analysis of patients undergoing hepatic tumour MWA utilizing two different systems over a 10-month period was carried out.

Results

Data for a total of 48 patients with a mean age of 58 ± 1.24 years were analysed. A total of 124 tumours were ablated; 72 tumours were ablated with a 915-MHz system and 52 with a 2.45-GHz system. Mean tumour diameters were 1.7 ± 0.1 cm in the 915-MHz group and 2.5 ± 0.2 cm in the 2.45-GHz group (P < 0.01). Mean ablation time per burn was 8.1 ± 0.3 min in the 915-MHz group and 4.0 ± 0.1 min in the 2.45-GHz group (P < 0.01). The mean number of burns per lesion was 2.0 ± 0.1 in the 915-MHz group and 1.7 ± 0.1 in the 2.45-GHz group (P < 0.05). The mean ablation time per lesion was 9.7 ± 0.7 min in the 915-MHz group, and 6.6 ± 0.6 min in the 2.45-GHz group (P < 0.01). The 2.45-GHz system demonstrated a better correlation between ablation time and tumour size (r² = 0.6222) than the 915-MHz system; (r² = 0.0696). Mean total energy applied per lesion, and energy applied per cm, were greater with the 915-MHz system (P < 0.05 and P < 0.01, respectively). Total energy applied per lesion was similarly correlated for the 2.45-GHz (r² = 0.6263) and 915-MHz (r² = 0.7012) systems. Mean total energy applied per cm/min was greater with the 2.45-GHz system (P < 0.05).

Conclusions

Both 915-MHz and 2.45-GHz MWA systems achieve reproducible hepatic tumour ablation. The 2.45-GHz system achieves equivalent, but more predictable and faster ablations using a single antenna system.     

Endoscopic ablation of Barrett＇s esophagus using high power setting argon plasma coagulation： A prospective study

AIM: This prospective study evaluated the effectiveness of 90 W argon plasma coagulation (APC) for the ablation of Barrett's esophagus (BE) that is considered to be the main risk factor for the development of esophageal adenocarcinoma. METHODS: The results from 25 patients, observed at the First Department of General Surgery, University of Verona, Italy, from October 2000 to October 2003, who underwent APC for histologically proven BE were prospectively analyzed, RESULTS: The ablation treatment was completed in all the patients but one (96%). The mean number of APC sessions needed to complete ablation was 1.6 (total number: 40). The eradication was obtained in the majority of cases by one session only (60%), two sessions were required in 24% of the cases and three or more in 16%. About 43% of the sessions were complicated. Retrosternal pain (22.5%) and fever (17.5%) were the most frequent symptoms. Only one major complication occurred, it was an hemorrhage due to ulcer formation on the treated esophagus that required urgent endoscopic sclerosis and admission. The follow-up was accomplished in all the patients with a mean period of 26.3 mo and 20 patients (84%) with a follow-up period longer than 24 mo. Only one patient showed a relapse of metaplastic mucosa 12 mo after the completion of ablation. The patient was hence re-treated and now is free from recurrence 33 mo later. CONCLUSION: High power setting (90 W) APC showed to be safe and effective. The effects persist at a mean follow-up period of two years with a comparable cost in term of complications with respect to standard power settings. Further studies with greater number of patients are required to confirm these results and to assess if ablation reduces the incidence of malignant progression.     

A successful treatment for hepatocellular carcinoma with Osler–Rendu–Weber disease using radiofrequency ablation under laparoscopy

Hepatocellular carcinoma (HCC) can be difficult to diagnose and treat in patients with Osler–Rendu–Weber disease due to vascular malformation and regenerative nodular hyperplasia. In addition, percutaneous liver puncture should be avoided for the diagnosis and treatment as the procedure carries a high risk of bleeding. We herein report the successful treatment of HCC in a patient with Osler–Rendu–Weber disease using radiofrequency ablation (RFA) under laparoscopy. A 71-year-old man with Osler–Rendu–Weber disease was admitted to our hospital for the treatment of HCC. He also had chronic hepatitis C virus infection. The arterioportal shunts in the liver were detected by computed tomography (CT) and angiography. A tumor 20 mm in size was detected as a defected-lesion in the hepatic segment IV during the portal phase by CT. RFA under laparoscopy was performed for the curative treatment for HCC, with sufficient ablation obtained. Although the blood gushed out from the needle tract at the end of the procedure, complete hemostasis was achieved promptly using coagulation forceps. The post-operative course was favorable. Thus, laparoscopic RFA is a useful treatment modality for HCC in patients with Osler–Rendu–Weber disease, as a hemostasis device can be used with direct visualization.     

Localization of fossa ovalis and Brockenbrough needle prior to left atrial ablation using three-dimensional mapping with EnSite Fusion™

Background  

Transseptal catheterization of the interatrial septum has traditionally been performed under the guidance of fluoroscopy, echocardiography, and hemodynamic pressure monitoring. We hypothesized that the fossa ovalis could be identified on pre-ablation chest computerized tomography (CT) scan utilizing EnSite Verismo™ and Fusion™ software thereby permitting its real-time visualization during transseptal puncture.     

The therapeutic effects of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation for rheumatic valve disease combined with permanent atrial fibrillation

Objective The present study was designed to evaluates the short term effect of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation (BPRF) on the combination of rheumatic valve disease and long-standing permanent atrial fibrillation(AF). Methods Thirteen cases of rheumatic valve dis-ease with permanent AF received BPRF modified Cox-Maze Ⅲ procedure using the Medtronic Cardioblate BP system from May 2007 to May 2008. The therapeutic effect was evaluated. Results The average age of the pa-tients were 56.5 (range 44-65) years,average duration of AF were 5 (2-11) years and the average left atrial diameter was (55.1±5.9) mm. No mortalities or severe complications were seen in all the 13 patients during the study period. The average time for cross clamping of the aorta was 10 min. The AF was disappeared in all 13 patients immediately after the procedure. Successful restoration of sinus rhythm has been achieved in 12 pa-tients (92.3%) during the follow-up of 6-17 (9.2±3.2) months,while one patient had recurrence of AF. Conclusion The Cox-Maze Ⅲ procedure with BPRF using the Medtronic Cardioblate BP system is a safe and effective treatment for patients suffering from rheumatic valve disease combined with permanent AF. ±3.2     

The therapeutic effects of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation for rheumatic valve disease combined with permanent atrial fibrillation

Objective The present study was designed to evaluates the short term effect of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation (BPRF) on the combination of rheumatic valve disease and long-standing permanent atrial fibrillation(AF). Methods Thirteen cases of rheumatic valve dis-ease with permanent AF received BPRF modified Cox-Maze Ⅲ procedure using the Medtronic Cardioblate BP system from May 2007 to May 2008. The therapeutic effect was evaluated. Results The average age of the pa-tients were 56.5 (range 44-65) years,average duration of AF were 5 (2-11) years and the average left atrial diameter was (55.1±5.9) mm. No mortalities or severe complications were seen in all the 13 patients during the study period. The average time for cross clamping of the aorta was 10 min. The AF was disappeared in all 13 patients immediately after the procedure. Successful restoration of sinus rhythm has been achieved in 12 pa-tients (92.3%) during the follow-up of 6-17 (9.2±3.2) months,while one patient had recurrence of AF. Conclusion The Cox-Maze Ⅲ procedure with BPRF using the Medtronic Cardioblate BP system is a safe and effective treatment for patients suffering from rheumatic valve disease combined with permanent AF. ±3.2     

The therapeutic effects of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation for rheumatic valve disease combined with permanent atrial fibrillation

Objective The present study was designed to evaluates the short term effect of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation (BPRF) on the combination of rheumatic valve disease and long-standing permanent atrial fibrillation(AF). Methods Thirteen cases of rheumatic valve dis-ease with permanent AF received BPRF modified Cox-Maze Ⅲ procedure using the Medtronic Cardioblate BP system from May 2007 to May 2008. The therapeutic effect was evaluated. Results The average age of the pa-tients were 56.5 (range 44-65) years,average duration of AF were 5 (2-11) years and the average left atrial diameter was (55.1±5.9) mm. No mortalities or severe complications were seen in all the 13 patients during the study period. The average time for cross clamping of the aorta was 10 min. The AF was disappeared in all 13 patients immediately after the procedure. Successful restoration of sinus rhythm has been achieved in 12 pa-tients (92.3%) during the follow-up of 6-17 (9.2±3.2) months,while one patient had recurrence of AF. Conclusion The Cox-Maze Ⅲ procedure with BPRF using the Medtronic Cardioblate BP system is a safe and effective treatment for patients suffering from rheumatic valve disease combined with permanent AF. ±3.2     

The therapeutic effects of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation for rheumatic valve disease combined with permanent atrial fibrillation

Objective The present study was designed to evaluates the short term effect of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation (BPRF) on the combination of rheumatic valve disease and long-standing permanent atrial fibrillation(AF). Methods Thirteen cases of rheumatic valve dis-ease with permanent AF received BPRF modified Cox-Maze Ⅲ procedure using the Medtronic Cardioblate BP system from May 2007 to May 2008. The therapeutic effect was evaluated. Results The average age of the pa-tients were 56.5 (range 44-65) years,average duration of AF were 5 (2-11) years and the average left atrial diameter was (55.1±5.9) mm. No mortalities or severe complications were seen in all the 13 patients during the study period. The average time for cross clamping of the aorta was 10 min. The AF was disappeared in all 13 patients immediately after the procedure. Successful restoration of sinus rhythm has been achieved in 12 pa-tients (92.3%) during the follow-up of 6-17 (9.2±3.2) months,while one patient had recurrence of AF. Conclusion The Cox-Maze Ⅲ procedure with BPRF using the Medtronic Cardioblate BP system is a safe and effective treatment for patients suffering from rheumatic valve disease combined with permanent AF. ±3.2     

The therapeutic effects of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation for rheumatic valve disease combined with permanent atrial fibrillation

Objective The present study was designed to evaluates the short term effect of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation (BPRF) on the combination of rheumatic valve disease and long-standing permanent atrial fibrillation(AF). Methods Thirteen cases of rheumatic valve dis-ease with permanent AF received BPRF modified Cox-Maze Ⅲ procedure using the Medtronic Cardioblate BP system from May 2007 to May 2008. The therapeutic effect was evaluated. Results The average age of the pa-tients were 56.5 (range 44-65) years,average duration of AF were 5 (2-11) years and the average left atrial diameter was (55.1±5.9) mm. No mortalities or severe complications were seen in all the 13 patients during the study period. The average time for cross clamping of the aorta was 10 min. The AF was disappeared in all 13 patients immediately after the procedure. Successful restoration of sinus rhythm has been achieved in 12 pa-tients (92.3%) during the follow-up of 6-17 (9.2±3.2) months,while one patient had recurrence of AF. Conclusion The Cox-Maze Ⅲ procedure with BPRF using the Medtronic Cardioblate BP system is a safe and effective treatment for patients suffering from rheumatic valve disease combined with permanent AF. ±3.2     

The therapeutic effects of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation for rheumatic valve disease combined with permanent atrial fibrillation

Objective The present study was designed to evaluates the short term effect of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation (BPRF) on the combination of rheumatic valve disease and long-standing permanent atrial fibrillation(AF). Methods Thirteen cases of rheumatic valve dis-ease with permanent AF received BPRF modified Cox-Maze Ⅲ procedure using the Medtronic Cardioblate BP system from May 2007 to May 2008. The therapeutic effect was evaluated. Results The average age of the pa-tients were 56.5 (range 44-65) years,average duration of AF were 5 (2-11) years and the average left atrial diameter was (55.1±5.9) mm. No mortalities or severe complications were seen in all the 13 patients during the study period. The average time for cross clamping of the aorta was 10 min. The AF was disappeared in all 13 patients immediately after the procedure. Successful restoration of sinus rhythm has been achieved in 12 pa-tients (92.3%) during the follow-up of 6-17 (9.2±3.2) months,while one patient had recurrence of AF. Conclusion The Cox-Maze Ⅲ procedure with BPRF using the Medtronic Cardioblate BP system is a safe and effective treatment for patients suffering from rheumatic valve disease combined with permanent AF. ±3.2     

The therapeutic effects of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation for rheumatic valve disease combined with permanent atrial fibrillation

Objective The present study was designed to evaluates the short term effect of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation (BPRF) on the combination of rheumatic valve disease and long-standing permanent atrial fibrillation(AF). Methods Thirteen cases of rheumatic valve dis-ease with permanent AF received BPRF modified Cox-Maze Ⅲ procedure using the Medtronic Cardioblate BP system from May 2007 to May 2008. The therapeutic effect was evaluated. Results The average age of the pa-tients were 56.5 (range 44-65) years,average duration of AF were 5 (2-11) years and the average left atrial diameter was (55.1±5.9) mm. No mortalities or severe complications were seen in all the 13 patients during the study period. The average time for cross clamping of the aorta was 10 min. The AF was disappeared in all 13 patients immediately after the procedure. Successful restoration of sinus rhythm has been achieved in 12 pa-tients (92.3%) during the follow-up of 6-17 (9.2±3.2) months,while one patient had recurrence of AF. Conclusion The Cox-Maze Ⅲ procedure with BPRF using the Medtronic Cardioblate BP system is a safe and effective treatment for patients suffering from rheumatic valve disease combined with permanent AF. ±3.2     

The therapeutic effects of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation for rheumatic valve disease combined with permanent atrial fibrillation

Objective The present study was designed to evaluates the short term effect of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation (BPRF) on the combination of rheumatic valve disease and long-standing permanent atrial fibrillation(AF). Methods Thirteen cases of rheumatic valve dis-ease with permanent AF received BPRF modified Cox-Maze Ⅲ procedure using the Medtronic Cardioblate BP system from May 2007 to May 2008. The therapeutic effect was evaluated. Results The average age of the pa-tients were 56.5 (range 44-65) years,average duration of AF were 5 (2-11) years and the average left atrial diameter was (55.1±5.9) mm. No mortalities or severe complications were seen in all the 13 patients during the study period. The average time for cross clamping of the aorta was 10 min. The AF was disappeared in all 13 patients immediately after the procedure. Successful restoration of sinus rhythm has been achieved in 12 pa-tients (92.3%) during the follow-up of 6-17 (9.2±3.2) months,while one patient had recurrence of AF. Conclusion The Cox-Maze Ⅲ procedure with BPRF using the Medtronic Cardioblate BP system is a safe and effective treatment for patients suffering from rheumatic valve disease combined with permanent AF. ±3.2     

The therapeutic effects of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation for rheumatic valve disease combined with permanent atrial fibrillation

Objective The present study was designed to evaluates the short term effect of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation (BPRF) on the combination of rheumatic valve disease and long-standing permanent atrial fibrillation(AF). Methods Thirteen cases of rheumatic valve dis-ease with permanent AF received BPRF modified Cox-Maze Ⅲ procedure using the Medtronic Cardioblate BP system from May 2007 to May 2008. The therapeutic effect was evaluated. Results The average age of the pa-tients were 56.5 (range 44-65) years,average duration of AF were 5 (2-11) years and the average left atrial diameter was (55.1±5.9) mm. No mortalities or severe complications were seen in all the 13 patients during the study period. The average time for cross clamping of the aorta was 10 min. The AF was disappeared in all 13 patients immediately after the procedure. Successful restoration of sinus rhythm has been achieved in 12 pa-tients (92.3%) during the follow-up of 6-17 (9.2±3.2) months,while one patient had recurrence of AF. Conclusion The Cox-Maze Ⅲ procedure with BPRF using the Medtronic Cardioblate BP system is a safe and effective treatment for patients suffering from rheumatic valve disease combined with permanent AF. ±3.2     

The therapeutic effects of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation for rheumatic valve disease combined with permanent atrial fibrillation

Objective The present study was designed to evaluates the short term effect of modified Cox-Maze Ⅲ procedure using bipolar radiofrequency ablation (BPRF) on the combination of rheumatic valve disease and long-standing permanent atrial fibrillation(AF). Methods Thirteen cases of rheumatic valve dis-ease with permanent AF received BPRF modified Cox-Maze Ⅲ procedure using the Medtronic Cardioblate BP system from May 2007 to May 2008. The therapeutic effect was evaluated. Results The average age of the pa-tients were 56.5 (range 44-65) years,average duration of AF were 5 (2-11) years and the average left atrial diameter was (55.1±5.9) mm. No mortalities or severe complications were seen in all the 13 patients during the study period. The average time for cross clamping of the aorta was 10 min. The AF was disappeared in all 13 patients immediately after the procedure. Successful restoration of sinus rhythm has been achieved in 12 pa-tients (92.3%) during the follow-up of 6-17 (9.2±3.2) months,while one patient had recurrence of AF. Conclusion The Cox-Maze Ⅲ procedure with BPRF using the Medtronic Cardioblate BP system is a safe and effective treatment for patients suffering from rheumatic valve disease combined with permanent AF. ±3.2     

Can segmental pulmonary vein ablation reduce the recurrence of atrial fibrillation when using a higher RF power, larger tip electrode catheter, and additional RF deliveries?: the limitations of point-by-point RF ablation

The aim of this study was to investigate whether segmental ostial catheter ablation (SOCA) designed to prevent the electrical connections (ECs) between the left atrium and pulmonary veins (PVs) might help increase the efficacy of SOCA in paroxysmal atrial fibrillation (PAF). PV mapping and successful SOCA were performed with a basket catheter in 108 consecutive patients with PAF. Radiofrequency energy was delivered using a maximum output of 30 W with a 4 mm tip catheter (group I; 47) or 40 W with an 8 mm tip catheter (group II; 61). Only in the group II patients were additional radiofrequency deliveries to the specific sites where the ECs tended to recover performed after successful SOCA. After the first procedure, PAF recurred in 47% of the group I patients and 32% of the group II patients. In all 27 patients who underwent repeat procedures, EC recoveries were observed more frequently in group I than in group II (69% versus 49%; P < 0.05). After multiple procedures, there was more freedom from PAF in group II (84%) than in group I (66%) (P < 0.05). SOCA with a higher RF power, larger tip catheter, and additional RF deliveries could achieve a more effective SOCA.     

Endoscopic ablation of Barrett’s esophagus

Barrett’s esophagus is a premalignant lesion of the esophagus that arises as an abnormal tissue response to epithelial injury from gastroesophageal reflux. Barrett’s esophagus has previously been considered an irreversible lesion that required life-long surveillance to prevent malignant transformation. Recently, combination therapy with pharmacologic or surgical control of acid reflux combined with endoscopic delivery of a mucosal injury appears to have the capability of reversing superficial Barrett’s tissue, and perhaps deeper tissue as well. Whether Barrett’s esophagus is cured and cancer/dysplasia prevented by these techniques will require long-term follow-up of these patients.