Transvenous Radiofrequency Catheter Ablation for an Aldosterone-Producing Tumor of the Left Adrenal Gland: A First in Human Case Report.

PURPOSE: To describe a novel technique of transvenous radiofrequency catheter ablation of an aldosterone-producing adenoma (APA) of the left adrenal gland using the GOS System (Japan Lifeline, Tokyo, Japan). Using the GOS system, a flexible radiofrequency tip catheter can be inserted into the adrenal central and tributary veins, the drainers for functional tumors. MATERIALS AND METHODS: An APA at the left adrenal gland, which was diagnosed by segmental adrenal venous sampling following administration of 0.25 mg cosyntropin, was ablated using the GOS catheter inserted into adrenal tributary veins via a right femoral vein 7-Fr sheath. The effect of radiofrequency ablation on APA was assessed using the international consensus on surgical outcomes for unilateral primary aldosteronism (PA). RESULTS: No device-related complications were observed. The patient was deeply sedated under blood pressure and heart rate control with continuous administration of ß-blockers. Then, the tumor and surrounding adrenal gland were cauterized at 7000 J two times each in sequence. The output time was 7-11 min for each ablation and 80 min in total. For blood pressure and pulse rate control, esmolol hydrochloride and phentolamine mesylate were used. The contrast enhancement of APA disappeared on dynamic CT immediately after the procedure. PA was biochemically cured until 12 months after the procedure. CONCLUSION: Using the radiofrequency device with the GOS catheter and system is a method for cauterizing adrenal tumors from blood vessels. This approach resulted in a marked reduction in aldosterone concentrations and a complete biochemical cure of PA over the observation period.

Transvenous Radiofrequency Ablation of Adrenal Gland: Experimental Study.

PURPOSE: The aim was to evaluate a flexible device for transvenous adrenal gland radiofrequency ablation in vitro and in an in vivo animal model. MATERIALS AND METHODS: A flexible radiofrequency-tip catheter with an inner-cooling mechanism and a guidewire lumen was made. Then, using a polyvinyl alcohol gel model, the ablation diameter was evaluated and how much energy to deliver in vivo was determined. Finally, transvenous radiofrequency ablation of the left adrenal glands of two pigs was performed, delivering 5000 or 7000 J in a single dose to each. The ablation effects were also assessed by histological examination of hematoxylin-eosin-stained sections. RESULTS: The mean ablation diameters in the gel model were 20.2 and 21.9 mm in the short axis and 15 and 20 mm in the long axis for 5000 or 7000 J, respectively. The device was inserted into porcine left adrenal vein with no complications. The mean ablation diameters were 10 mm in the shorter axis (whole thickness of porcine left adrenal gland) in the porcine model for 7000 J. Transient increases in blood pressure and heart rate occurred during ablation. Histologically, the adrenal gland showed severe necrosis at ablated area. There was venous congestion upstream in a non-ablated area, and thermal damage to surrounding organs was not observed. CONCLUSIONS: A flexible radiofrequency-tip catheter could be inserted successfully into the left adrenal vein. The left adrenal gland was entirely ablated without any thermal damage to surrounding organs. We suggest transvenous adrenal ablation has potential as a therapeutic option for primary aldosteronism.

Radiofrequency Ablation by a 21-Gauge Internally Cooled Electrode: Ex Vivo and In Vivo Evaluation by Rat Liver.

PURPOSE: To evaluate the coagulative performance of a 21-gauge (G) internally cooled radiofrequency (RF) electrode using ex vivo and in vivo rat liver. MATERIALS AND METHODS: We developed a prototype of 21-G internally cooled monopolar RF electrode with 5.0 mm active tip length. The ablative zone size created by this electrode was evaluated in ex vivo and in vivo rat liver. Five RF powers (3 W, 5 W, 7 W, 9 W, and 11 W) were applied with and without circulation of chilled water within the electrode. The ablation zone sizes were compared. Histopathological evaluation of the ablation zone was also performed at 24 h and at 7 days after RF ablation. RESULTS: From ex vivo experiments, the ablation volume was found to increase significantly when RF energy was applied with the chilled water circulation. Results of in vivo experiments demonstrate that the ablation volume reached its maximum value when RF power of 7 W was applied (532.3 ± 110.3 mm3). Histopathological examination showed delineated coagulation necrosis at 24 h after RF ablation, which clarified the ablation zone border. Fibrotic change was also observed at 7 days after RF ablation. CONCLUSION: RF ablation using a 21-gauge electrode produced coagulation necrosis in the rat liver. The ablation volume became maximum when RF power of 7 W was applied with chilled water circulation.