Bize, Pierre

de Baere, Thierry

Demartines, Nicolas

Denys, Alban

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LETTER TO THE EDITORPortal Vein Embolization: From Evidence to Expert Opinion?Alban Denys • Thierry de Baere • Nicolas Demartines •Pierre BizeReceived: 4 April 2012 / Accepted: 18 April 2012 / Published online: 15 May 2012 Springer Science+Business Media, LLC and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) 2012Dr. Madoff’s remarks address three different points. First,he addresses the difficult issue of extending the right portalvein embolization (PVE) to segment 4 branches in case ofplanned extended right hepatectomy. He states that weimproperly cited his publication [6]. We agree that rightPVE extended to segment 4 is not intended to hypertrophythe whole left liver (segments 2, 3, and 4). Dr. Madoff musthave been confused by our use of ‘‘left lobe’’ of the liver, aterm he seems to confuse with ‘‘left liver.’’ Anatomicclassification of liver segments as well as their name variesamong different areas in the world. Nevertheless, in themost widely accepted textbook of liver surgery [1] as wellas in most surgical centers, the left lobe is the part of theliver located medial to the falciform ligament—that is,segments 2 and 3 in the Couinaud nomenclature. Usingthese terms, our sentence is correct and properly reflectsDr. Madoff’s own statement. Dr. Madoff argues that hispublication does not demonstrate that segment 4 emboli-zation improves the hypertrophy rate of the left lobe.However, in the same reference [6], Dr. Madoff writes inthe discussion that ‘‘the experience reported herein high-lights…the advantage of segment 4 embolization and theadvantages of embolization with small spherical particlesused in combination with coils.’’ Despite his ownstatement, we recognize, as mentioned in his letter, that thisretrospective study more clearly reflects the potentialbenefit of small particles over nonspherical ones, ratherthan the benefit of segment 4 branches embolization. Inanother sentence, he recognizes that segment 4 branchembolization needs ‘‘extreme care to avoid reflux in seg-ments 2 and 3 branches,…and may require substantiallymore time and contrast than right PVE.’’ In another article,surprisingly, segment 4 increased in volume after right ? 4PVE (?26 % similarly to right PVE ?20 %); this findingmight reflect the difficulty in recognizing all segment 4branches and/or completely occluding all of them [5].Other centers reviewing the largest series published to datehave not found a difference in hypertrophy of the futureremnant liver between these two techniques [3]. The finalanswer to this point should be provided by randomizedtrial, but in the meantime, we recommend that segment 4branch embolization should be performed only by experi-enced interventional radiologists and when anatomy isappropriate (large segment 4 branches) using easily con-trollable embolic material.Second, Dr. Madoff comments on the choice of theembolic agent for PVE. Nearly all commercially availableembolic agents have been used for PVE and produced,more or less, left liver hypertrophy after right PVE. Fromthe patient’s perspective, the choice of the ‘‘best’’ embolicagent should be according to whether it performs better atinducing higher hypertrophy of the future remnant liver,whether it has a lower rate of complications but workssimilarly, or both. The authors state that there is only one‘‘small animal study’’ comparing NBCA (n-butyl-cyano-acrylate) to spherical particles, thus supporting the use ofNBCA versus spherical particles in terms of performance[2]. Recently, another experimental publication demon-strated the same results [8] when comparing NBCA toA. Denys (&)  P. BizeDepartment of Radiology and Interventional Radiology,Lausanne University Hospital, 1011 Lausanne, Switzerlande-mail: Alban.Denys@chuv.chT. de BaereDepartment of Interventional Radiology, Institut GustaveRoussy, 39 Rue Camille Desmoulins, 94800 Villejuif, FranceN. DemartinesDepartment of Visceral Surgery, Lausanne University Hospital,1011 Lausanne, Switzerland123Cardiovasc Intervent Radiol (2013) 36:872–873DOI 10.1007/s00270-012-0416-ysmall particles in an animal model using more recentevaluation technologies. It is interesting, as we point out inour review, that regeneration of the future remnant liverseems correlated to the periportal inflammation created inthe embolized liver by the embolic material [2]. This hasbeen demonstrated both in animals and in humans, and thisstrongly favors the use of NBCA as compared to particles,coils, and plugs, because NBCA induces little or no peri-portal inflammation. Concerning the complication rate, theonly large series that specifically addressed this point wasperformed on patients embolized with NBCA [4]. To ourknowledge, no series including the same number ofpatients and using particles specifically addressed thispoint. Nevertheless, severe complications like left portalvein thrombosis that can preclude further liver resection areobserved despite an ipsilateral approach and the use ofparticles [7]. Dr. Madoff’s citations of abstracts adds littleto this debate because these series have not been published,making their detailed analysis impossible.Finally, Dr. Madoff comments on the benefit of anipsilateral versus contralateral approach to the portal tree.Each approach carries both risks and advantages. It is alsorelated to the choice of the embolic material and to theanatomic territory that needs to be treated. In a recentreview, van Gulik et al. [9] quoted a survey conducted inthe Netherlands during 2006–2007. During this period,only 98 portal occlusions were performed in this country,only half of them by means of percutaneous emboliza-tion—the result of a lack of experienced interventionalradiologists. This honest statement clearly establishes thatPVE is a technique performed probably less than once amonth even in large centers, and each interventional radi-ologist must thus feel confident with the method that he orshe uses. In our review, we wanted to honestly present thebenefits and drawbacks of each access route. Practitionerscan then make an informed choice.Dr. Madoff’s contributions to the field of PVE areimpressive, as is his work with Nicolas Vauthey, a liversurgeon at the MD Anderson Cancer Center, Houston,Texas. They have made a lot to promote this technique thatwas invented in Japan and modified in Europe. We thusexpect that most of the questions his remarks raise will findmore robust response than only expert opinion.Conflict of interest The authors declare that they have no conflictof interest.References1. Blumgart L, Hann L (2007) Surgical, and radiological anatomy ofthe liver, biliary tract, and pancreas. In: Blumgart L (ed) Surgeryof the liver, biliary tract, and pancreas. Elsiever, Philadelphia,pp 3–302. de Baere T, Denys A, Paradis V (2009) Comparison of fourembolic materials for portal vein embolization: experimental studyin pigs. Eur Radiol 19:1435–14423. de Baere T, Teriitehau C, Deschamps F et al (2010) Predictivefactors for hypertrophy of the future remnant liver after selectiveportal vein embolization. Ann Surg Oncol 17:2081–20894. Di Stefano DR, de Baere T, Denys A et al (2005) Preoperativepercutaneous portal vein embolization: evaluation of adverseevents in 188 patients. Radiology 234:625–6305. Kishi Y, Madoff DC, Abdalla EK et al (2008) Is embolization ofsegment 4 portal veins before extended right hepatectomyjustified? Surgery 144:744–7516. Madoff DC, Abdalla EK, Gupta S et al (2005) Transhepaticipsilateral right portal vein embolization extended to segment IV:improving hypertrophy and resection outcomes with sphericalparticles and coils. J Vasc Interv Radiol 16(2 pt 1):215–2257. Madoff DC, Hicks ME, Abdalla EK, Morris JS, Vauthey JN (2003)Portal vein embolization with polyvinyl alcohol particles and coilsin preparation for major liver resection for hepatobiliary malig-nancy: safety and effectiveness—study in 26 patients. Radiology227(1):251–2608. Tsoumakidou G, Theocharis S, Ptohis N et al (2011) Liverhypertrophy after percutaneous portal vein embolization: compar-ison of N-butyl-2-cyanocrylate versus sodium acrylate–vinylalcohol copolymer particles in a swine model. CardiovascIntervent Radiol 34:1042–10499. van Gulik TM, van den Esschert JW, de Graaf W et al (2008)Controversies in the use of portal vein embolization. Dig Surg25:436–444A. Denys et al.: Portal Vein Embolization 873123

Portal Vein Embolization: From Evidence to Expert Opinion?

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Portal Vein Embolization: From Evidence to Expert Opinion?

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