Cardiovasc Intervent Radiol (2013) 36:245–248 DOI 10.1007/s00270-012-0451-8
TECHNICAL NOTE
Novel Percutaneous Radiofrequency Ablation of Portal Vein Tumor Thrombus: Safety and Feasibility Malkhaz Mizandari • Guokun Ao • Yaojun Zhang • Xi Feng • Qiang Shen • Minshan Chen • WanYee Lau Joanna Nicholls • Long Jiao • Nagy Habib
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Received: 19 April 2012 / Accepted: 6 July 2012 / Published online: 2 August 2012 Ó Springer Science+Business Media, LLC and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) 2012
Abstract Purpose We report our experience of the safety of partial recanalization of the portal vein using a novel endovascular radiofrequency (RF) catheter for portal vein tumor thrombosis. Methods Six patients with liver cancer and tumor thrombus in the portal vein underwent percutaneous intravascular radiofrequency ablation (RFA) using an endovascular bipolar RF device. A 0.035-inch guidewire was introduced into a tributary of the portal vein and through which a 5G guide catheter was introduced into the main portal vein. After manipulation of the guide catheter over the thrombus under digital subtraction angiography, the endovascular RF device was inserted and activated around the thrombus.
Electronic supplementary material The online version of this article (doi:10.1007/s00270-012-0451-8) contains supplementary material, which is available to authorized users. M. Mizandari High Technology Medical Center, Tbilisi State Medical University, 9 Tsinandali Street, 0144 Tbilisi, Georgia G. Ao Department on Oncology, The 309 Hospital of People’s Liberation Army, 17 HeiShanHu Road, HaiDian District, Beijing, China Y. Zhang X. Feng J. Nicholls L. Jiao N. Habib (&) Department of Surgery and Cancer, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK e-mail:
[email protected]
Results There were no observed technique specific complications, such as hemorrhage, vessel perforation, or infection. Post-RFA portography showed partial recanalization of portal vein. Conclusions RFA of portal vein tumor thrombus in patients with hepatocellular carcinoma is technically feasible and warrants further investigation to assess efficacy compared with current recanalization techniques. Keywords Endovascular radiofrequency ablation Catheter Portal vein thrombus
Introduction Portal vein thrombus (PVT) is a relatively common, but difficult, condition to manage in patients with liver cancer [1, 2]. It often indicates an advanced stage of disease with M. Chen Department of Hepatobiliary Surgery, Cancer Centre of Sun Yat-Sen University, 651 Dongfeng Road East, Guangzhou 510060, China W. Lau Department of Surgery, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China J. Nicholls N. Habib Department of Surgery, EMcision Limited, Hammersmith Hospital, Du Cane Road, London W12 0HS, UK
Q. Shen The First Minimally Invasive Department of Eastern Hepatobiliary Surgery Hospital, 800, Xiangyin Road, Shanghai, China
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Fig. 1 HabibTM VesOpen endovascular radiofrequency catheter. A 65-year-old male patient with HCC and right portal vein thrombosis
poor prognosis and is contraindicated for surgical thrombectomy [1, 2]. Liver parenchyma normally receives 70 % of its blood from the portal vein [3, 4]. As a result of PVT, a decrease in partial blood supply to the affected segments could occur, which may lead to further deterioration of liver function. Currently, there is no effective modality available to treat this condition. An endovascular bipolar radiofrequency (RF) catheter has been developed for percutaneous ablation of tumor thrombus (HabibTM VesOpen, EMcision Limited, London, UK; Fig. 1). Initial animal studies showed that the device could be used safely for vascular remodeling with increase in the luminal diameter and flow [5]. We report clinical application of this device in six patients with PVT.
Material and Methods Six patients with liver cancer and tumor thrombus in the portal vein underwent this new percutaneous procedure. Five patients had viral hepatitis and hepatocellular carcinoma (HCC), and the sixth had liver sarcoma. All patients were not considered candidates for surgery. Portal thrombosis was located in the right branch (3 patients), left branch (1 patient), and main portal vein (2 patients). The indications for interventions were deterioration in liver function. The device has been described elsewhere [5]. In brief, the HabibTM VesOpen is a CE marked, endovascular RF catheter, 110 cm in length, available in 5 Fr or 3 Fr. The catheter has two stainless steel electrodes at the tip and can be used with 2–50 W of power generated by an appropriate RF generator. It can be used in monopolar or bipolar mode. In monopolar mode, high-frequency current passes between the electrodes and grounding pad (patient electrode) applied to the patient. In bipolar mode, the high-frequency current passes between the two electrodes (Fig. 1). Under sedation and local anesthesia of 20 ml of 0.5 % Marcain (bupivacaine hydrochloride), the portal vein was approached via the anterior branch of the right portal vein through the intercostal space. An 18-G puncture needle
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accommodating a 0.035-inch guidewire was inserted into the right portal vein under the guidance of real-time ultrasound using a ‘‘Free Hand’’ needle guide technique. Following percutaneous puncture of the liver, 10 ml of Omnipaque (Iohexol) contrast media was injected under digital subtraction angiography (DSA) for visualization of the portal system to confirm the position of the needle and to guide the subsequent procedures. Once the puncture needle was in the correct position, it was removed after placement of a 0.035-inch guidewire into the right portal vein. Using this guidewire, a 5-G guide catheter was introduced into the right portal vein and through the thrombus. The position was confirmed by portography below and above the thrombus in the right portal vein. Finally, the VesOpen device was inserted over the guidewire for RF application. The VesOpen device was connected to a RF generator (RITA Medical Angiodynamics, USA) and 10 W of RF energy was applied for 2 min. Immediately after RF application, balloon angioplasty was performed with a 5F balloon catheter (Delivery device diameter 5F, Cook Medical, USA). The balloon was 30-mm (L) 9 10-mm diameter, with a burst pressure of 10 atmospheres. The balloon was inflated for 2 min. The whole process was repeated twice (Fig. 2A–C). At the end of the portography, the catheter was removed and the puncture site was covered with a Mepore dressing. After stable observation overnight, the patients were discharged home from the hospital. No portal pressure measurements were made in this cohort of patients. A video of the procedure is available as a Supplementary Video.
Results This approach was safely performed in all six patients of this series. Post-RFA portography revealed an immediate improvement of blood flow into hepatic parenchyma through the portal vein. There were no observed techniquespecific complications, such as hemorrhage, vessel perforation, or infection. The images obtained following the procedure still showed an in situ tumor thrombus, but it was much smaller, which allowed portal liver reperfusion.
Discussion Although transarterial chemoemobolization (TACE) and systemic chemotherapy are standard methods for management of advanced stage HCC [1–4], few effective treatment options are available for dealing with intravascular tumor spread. An endovascular RF catheter is described, which
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Fig. 2 A CT scan of 65-year-old male patient with HCC with tumor thrombus in the main branch of the right portal vein. B Pre-RFA portography showed the 5-Fr diameter guide catheter introduced over the guidewire into the portal vein through the thrombus, a filling
defect and reduced portal flow to the right lobe of liver. C Post-RFA portography showed partial recanalization of the right portal vein with restored blood flow to the right lobe of liver
was used safely to partially recanalize the thrombosed portal vein in conjunction with balloon dilatation after RF to the thrombus. Following endoportal RFA, tumor thrombus was still seen but smaller in size with concomitant increase in portal flow as demonstrated by portal venography and duplex Doppler scan. During RF, the energy passes between the electrodes and biological tissues to cause coagulation of a selected area. The pathophysiology of this phenomenon is that the high-frequency alternating electric current applied through the electrodes results in rapid movement of intracellular ions in opposite directions. Ionic motion creates frictional forces that generate heat around the electrodes and eventually, around the tissue surrounding the catheter. After heating the vessel wall, the RF catheter is removed immediately and followed by balloon angioplasty. The combination of thermal energy and balloon pressure has been proven to effectively remodel intraluminal atherosclerotic plaque and increase lumen diameter [5]. In vivo animal studies also showed that RFA thermal angioplasty could be performed safely and resulted in a greater increase in cross-sectional area in peripheral arteries than nonheated arteries after conventional balloon angioplasty [6, 7]. This approach has been successful in clearing blocked metal vascular stents, such as TIPS (data not shown). The theoretical benefit of this approach could be potentially threefold. First, it may destroy the tumor thrombus and prevent or delay widespread dissemination. Second, it may improve liver function and hence patients could be subsequent candidates for TACE, RF ablation, surgery, or chemotherapy. Third, it may lead to reduction of portal hypertension and therefore the likelihood of bleeding oesophageal varices. All of the above have not yet been proven by our pilot group and will be the subject of further study. Recanalization of the portal vein will be more
beneficial if it is followed by a therapeutic approach, such as TACE, otherwise, as we suggest, rethrombosis inevitably will occur. At this stage, it is not clear whether a vascular stent should be placed following RF ablation and how often the endoportal RFA procedure should be repeated. Intravascular RFA of tumor thrombus is a novel concept. The diminution of the tumor thrombus is probably due to desiccation of the lesion analogous to RFA of HCC tumors. Because the tumor was not removed from the portal vein for histological verification, it is difficult at this stage to ascertain the level of tumor destruction, whether the tumor was completely or partially destroyed. In the absence of biopsy, it is difficult to be certain that the occlusion was due to tumor thrombus and not venous thrombosis. However, it was highly suggestive as in all cases the tumor was in continuity with the portal venous thrombus. In this pilot study, apart from immediate improvement of intrahepatic portal flow, we did not observe any clear additional clinical benefit. This could have been because clearance of the portal thrombus was not followed up by more aggressive therapeutic modalities. It may be that recanalization of the portal vein will be more beneficial if it is followed by a therapeutic approach, such as TACE or RFA. Other studies have shown benefit with percutaneous direct intratumoral RF of tumor thrombosis in the portal circulation. Thanos et al. [8] reported direct RF ablation of portal vein tumor thrombus in continuity with hepatocellular carcinoma and observed patency of the portal vein 16 months after RF ablation. Likewise, Giorgio et al. [9] discussed the merit of percutaneous RF ablation of both the HCC nodule and the portal vein tumor thrombus and concluded that this approach has high efficacy and safety and a low rate of complications. They also observed a highly statistical difference improved survival following the procedure.
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Conclusions We report a novel location for a recanalization procedure using percutaneous RFA technology. Six patients safely underwent partial recanalization of portal vein with this new RF endovascular device. Longer follow-up is needed to assess any potential clinical usefulness of intravascular RFA. Conflict of interest Joanna Nicholls and Nagy Habib are shareholders and directors of EMcision Limited, the company that developed the HabibTM VesOpen device. None of the other authors have a conflict of interest or a financial disclosure to declare.
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