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LETTERS TO THE EDITOR

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Transjugular Intrahepatic Portosystemic

Shunt Occlusion via Modified Pringle

Maneuver for Radiofrequency Ablation

of Nearby Tumor

From: Uei Pua, MBBS, MMed, FRCR, FAMSSundeep Punamiya, MD, FAMSDepartment of Diagnostic Radiology (U.P., S.P.)Tan Tock Seng Hospital11 Jalan Tan Tock SengSingapore 308433; andYong Loo-Lin School of Medicine (U.P.)National University of SingaporeSingapore

ABBREVIATIONS

HCC � hepatocellular carcinoma, RF � radiofrequency,TIPS � transjugular intrahepatic portosystemic shunt

Editor:

Tumor growing beside a transjugular intrahepatic portosystemicshunt (TIPS) is an uncommon occurrence, but poses a challengefor radiofrequency (RF) ablation as a result of the heat-sink effectof the TIPS. We describe such a case, in which we used tempo-rary balloon occlusion of the TIPS as a modified Pringle maneu-ver to achieve successful RF ablation of a nearby tumor.

A 59-year-old man who was awaiting liver transplanta-tion for nonalcoholic steatohepatitis–related liver cirrhosis un-derwent successful emergency TIPS creation and duodenalvarix embolization for recurrent gastrointestinal hemorrhagesecondary to portal hypertension. Computed tomography (CT)

Neither of the authors has identified a conflict of interest.

DOI: 10.1016/j.jvir.2011.12.505

Figure 1. (a) Coronal T2 and (b) Doppler US show the tumor (

curved arrow, b). The TIPS was patent, with vascular flow within (str

mages before TIPS creation demonstrated a small 2.0-cm hepa-ocellular carcinoma (HCC) in segment 8 of the liver. It waselieved that there was sufficient room for the TIPS to be createdell away from the HCC without significant technical difficulty.his was confirmed on CT immediately after TIPS creation,hich showed a 1-cm space between the HCC and TIPS.

However, 2 months after TIPS creation, surveillance ul-rasound (US) showed a significant increase in size of theCC to 3.2 cm in diameter, with the medial margin abutting

he TIPS without intervening liver (Fig 1), and local tumorblation was performed. The approach chosen in this case was toombine RF ablation with temporary balloon-occlusion TIPS, theatter to minimize TIPS-related heat-sink effect and allow ade-uate ablation of the portion of tumor abutting the shunt.

Via a right internal jugular vein access, the TIPS wasccessed and pressure measurements were obtained. A 5-Fogarty arterial embolectomy balloon (Edwards Life Sciences,rvine, California) was inserted through a 6-F sheath (10 cmength; Pinnacle; Terumo, Somerset, New Jersey) and posi-ioned within the intraparenchymal portion of the shunt. Aool-tip clustered RF probe (Covidien, Boulder, Colorado)ith three parallel needles (4.5-cm ablation zone) was then

nserted into the tumor under US guidance. Before commence-ent of ablation, the Fogarty balloon was inflated, occluding

he TIPS. The tumor was ablated for a total of 12 minutesccording to manufacturer recommendations for the probe sizesed, achieving a maximum tip temperature of 82°C (Fig 2).fter needle tract ablation, the Fogarty balloon was deflated,

nd the postablation pressure measurements revealed nohange in the shunt gradient of 10 mm Hg.

TIPS venography confirmed continued TIPS patency. Im-ediate contrast-enhanced CT showed that the ablation zone

xtended to the TIPS, completely encompassing the tumorFig 3). The portal vein and hepatic veins showed normalnhancement on CT, with no evidence of thrombosis that

k) to have extended, with the medial margin abutting the TIPS

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564 � Letters to the Editor Pua and Punamiya � JVIR

could have resulted from flow stagnation during temporaryTIPS occlusion or thermal injury. Surveillance Doppler US ofthe TIPS at 1 week, 1 month, and 3 months confirmed shuntpatency, and there was no local tumor recurrence or TIPSdysfunction at 12 months of follow-up (Fig 4).

The heat-sink effect, the Achilles heel of RF ablation, is

Figure 2. Fluoroscopic image during active ablation with clusteredRF ablation needles (black arrow) shows an inflated Fogarty balloon(white arrow) positioned within the middle of the TIPS, occluding theshunt, effectively removing the heat sink to allow effective RF abla-tion. Also note the incidental presence of multiple gallstones.

Figure 3. Coronal CT image immediately after ablation showsypodense ablation zone (asterisk) extending to the lateral mar-in of the TIPS (arrow), encompassing the entire tumor.

considered to be present when a blood vessel 3 mm or larger p

s in the vicinity of tumor (ie, � 5 mm) (1). To enhance RFblation of perivascular tumors, occlusion of blood flow by theringle maneuver (ie, temporary ligature or clamping of portalein) has been described in the surgical literature (2). Subse-uent adoption of this principle came in the form of percutaneousalloon occlusion of portal or hepatic veins (3). Based on therinciple of these earlier techniques, we performed TIPS occlu-ion to eliminate this iatrogenic heat sink for RF ablation.

As an alternative to RF ablation, microwave ablation—eemed the least heat sink–sensitive of all thermal ablativeechnologies—was considered (4). However, in view of theaucity of literature detailing the safety of thermal ablationncroaching into a TIPS, it was believed that the TIPS wouldave to be accessed and monitored on a periprocedural basisegardless to detect possible shunt dysfunction or complicationeg, thrombosis). Coupled with our familiarity with RF ablationompared with microwave ablation and the lower cost ofhe former, RF ablation with temporary shunt occlusion waslected.

A tumor near a TIPS presents a unique challenge toblative therapy. Besides the inherent high vascular flowith attendant heat-sink effect on thermal ablation thatIPS poses, the thermal ablative effects RF ablation has onIPS patency and the polytetrafluoroethylene material of

he VIATORR endoprosthesis (W.L. Gore and Associates,lagstaff, Arizona) remain unknown. This case suggests

hat the temperatures within the RF ablation range of 50°C–00°C may not have a deleterious effect on the TIPS

igure 4. Coronal subtraction T1 MR image in the arterialhase 3 months after RF ablation shows no enhancement in theblated tumor (asterisk), consistent with complete tumor abla-ion with no recurrence. Contrast enhancement of the TIPSumen alludes to shunt patency.

atency or stent-graft, that an ablation zone abutting the

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Volume 23 � Number 4 � April � 2012 565

endoprosthesis can be safely achieved, and that this modi-fied Pringle maneuver is a feasible technique in this setting.

REFERENCES

1. Hong K, Georgiades C. Radiofrequency ablation: mechanism of actionand devices. J Vasc Interv Radiol 2010; 21(suppl):S179–S186.

2. Shen P, Fleming S, Westcott C, Challa V. Laparoscopic radiofrequencyablation of the liver in proximity to major vasculature: effect of the Pringlemaneuver. J Surg Oncol 2003; 83:36–41.

3. de Baere T, Deschamps F, Briggs P, et al. Hepatic malignancies: percu-taneous radiofrequency ablation during percutaneous portal or hepaticvein occlusion. Radiology 2008; 248:1056–1066.

4. Lubner MG, Brace CL, Hinshaw JL, Lee FT Jr. Microwave tumor abla-tion: mechanism of action, clinical results, and devices. J Vasc IntervRadiol 2010; 21(suppl):S192–S203.

Transvenous Creation of a Mesocaval

Shunt: Report of Use in the

Management of Extrahepatic Portal

Vein Occlusion

From: John M. Moriarty, MRCPI, FFR(RCSI)Nima Kokabi, MDStephen T. Kee, MDDepartment of Radiological Sciences (J.M.M., S.T.K.)David Geffen School of MedicineUniversity of California, Los AngelesPeter V. Ueberroth Building, Suite 337110945 LeConte Ave.Los Angeles, CA 90095-7206; andFaculty of Medicine (N.K.)Northern Clinical School, Royal North Shore HospitalUniversity of SydneySydney, Australia

Editor:

The creation of a transjugular intrahepatic portosystemicshunt (TIPS) has become a standard procedure for thetreatment of variceal hemorrhage in the setting of portalhypertension (1). However, TIPS creation becomes pro-gressively more difficult with portal vein (PV) thrombosis,and even more so with PV occlusion (2).

Definitive management of extrahepatic PV occlusion ismost commonly performed with surgical creation of a me-sosystemic or portosystemic shunt, such as a splenorenalshunt; however, this is not feasible in every patient. Trans-venous minimally invasive methods of extraanatomic shuntformation have been a source of investigation recently (3),and the technique has been described in animals (4,5).

Here, we present a 57-year-old Hispanic man with a5-year history of metastatic colorectal carcinoma and mul-tiple previous surgical metastasectomies and courses ofchemotherapy and radiation therapy, who presented to theemergency department at our institution after a collapse

None of the authors have identified a conflict of interest.

RDOI: 10.1016/j.jvir.2011.09.023

ith hematemesis and melena. The patient underwentmergent endoscopy in which extensive gastric varicealessels and diffuse background submucosal changes weredentified that were consistent with portal gastropathy andeemed unsuitable for definitive endoscopic therapy. Theatient was subsequently referred to the interventional radiol-gy unit for evaluation and potential TIPS creation. Review ofecent imaging demonstrated a widely patent intrahepatic por-al venous system within the hepatic remnant; however, aong-segment occlusion of the extrahepatic PV with cavernousransformation was noted. A transjugular intrahepatic portalecanalization attempt was unsuccessful despite successfulatheterization of a normal-caliber intrahepatic PV. The pa-ient was considered for surgical shunt formation, but waseemed unsuitable because of the multiple previous intraab-ominal procedures and possible carcinomatosis identified onross-sectional imaging.

Extrahepatic, percutaneous, mesocaval shunt formationith the use of a covered stent-graft between the inferiorena cava (IVC) and superior mesenteric vein (SMV) underomputed tomographic (CT) and fluoroscopic guidance wasescribed by Nyman et al (6). In the present case, cross-ectional imaging had shown that the dilated proximalMV was 1.9 cm anterior to the IVC, with no majorascular structures between the two vessels. Although theigh risk of uncontrollable intraabdominal hemorrhage wascknowledged in preprocedural planning and before obtain-ng consent from the patient, no other suitable treatmentptions were apparent at that time.

Following the guidelines set out by Nyman et al (6), aesocaval shunt was formed between the IVC and a branch

f the SMV with the following steps: the patient wasrought to the angiography suite, and, under fluoroscopicuidance, a trilobed snare was passed from the right internalugular vein to the IVC, directly posterior to the SMV. Thenare was secured in situ and the patient was transferred tohe CT unit, where general anesthesia was induced. UnderT guidance and with the use of strict aseptic techniqueith antibiotic prophylaxis, a 22-gauge Chiba needle was

dvanced via transgastric approach to the SMV. The needleas then advanced into the IVC and snare. A 300-cm �.014-inch Hi-Torque Balance Middle Weight (BMW)uide wire (Guidant, Temecula, California) was passedhrough the Chiba needle and captured by the snare (Fig-re, a). The patient was then transferred back to the an-iography suite, where, under fluoroscopic guidance,he BMW wire was delivered through a 10-F sheath inhe internal jugular vein. Although a femoral approach wasonsidered, a jugular approach was chosen to aid in direct-ng the eventual stent cephalad within the IVC. A 4-Fnd-hole catheter was then advanced from the jugular ac-ess over the BMW wire into the IVC and subsequentlycross to the SMV. Position was confirmed with venogra-hy, and a second 0.014-inch BMW wire was passed to aistal branch of the SMV as a safety wire. The transab-ominally placed wire was then removed, and a 0.035-inch

osen wire (Cook, Bloomington, Indiana) was passed to