Bleeding Gastric Varices Obliteration with Balloonoccluded Retrograde Transvenous Obliteration Using Sodium Tetradecyl Sulfate Foam

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1 CLINICAL STUDY Bleeding Gastric Varices Obliteration with Balloonoccluded Retrograde Transvenous Obliteration Using Sodium Tetradecyl Sulfate Foam Saher S. Sabri, MD, Warren Swee, MD, Ulku C. Turba, MD, Wael E.A. Saad, MB, BCh, Auh W. Park, MD, Abdullah M. Al-Osaimi, MD, Stephen H. Caldwell, MD, Alan H. Matsumoto, MD, and John F. Angle, MD ABSTRACT Purpose: Balloon-occluded retrograde transvenous obliteration (BRTO) of bleeding gastric varices (GV) is well described in the literature. Using Ethanolamine oleate as the sclerosing agent in BRTO, but it is not readily available in the United States in the desired concentrations. The authors aim is to describe their initial experience with BRTO using sodium tetradecyl sulfate (STS) foam as an alternative sclerosing agent. Materials and Methods: The authors performed a retrospective review of their initial series in which STS foam was used to treat bleeding GV using BRTO. All study subjects had endoscopic evidence of gastric variceal bleeding. STS foam was made using a combination of agents with a 3:2:1 ratio of gas: 3% STS: Lipiodol (Ethiodol; Savage Laboratories, Melville, New York). Mean values and ranges were calculated for each variable, and clinical and imaging outcomes were assessed. Results: The authors performed BRTO in 22 cirrhotic patients (11 men and 11 women) with a mean age of 52 years (range, years). Technical success was achieved in 20 of 22 (91%) patients. Complications occurred in three of 22 (14%) patients. The overall mean dose of STS used was 300 mg (range, mg) with mean total volume of sclerosant mixture of 34.1 ml (range, ml). Follow-up imaging was available for 18 of 20 (90%) technically successful procedures with a mean period of 89 days (range, days). Complete obliteration of GV was achieved in 16 of 18 (89%) patients. There were no cases of recurrent variceal bleeding with a mean clinical follow-up period of 130 days (range, 1 510). Conclusions: BRTO utilizing STS foam appears effective in obliterating bleeding GVs with good short-term outcomes. ABBREVIATIONS BRTO balloon-occluded retrograde transvenous obliteration, EBC endoscopic N-butyl-2-cyanoacrylate, EO ethanolamine oleate, EUS endoscopic ultrasound, GRS gastrorenal shunt, GV gastric varices, STS sodium tetradecyl sulfate, TIPS transjugular intrahepatic portosystemic shunts From The Division of Angiography, Interventional Radiology, and Special Procedures, Department of Radiology (S.S.S., W.S., U.C.T., W.E.A.S., A.W.P., A.H.M., J.F.A.) and Division of Gastroenterology, Department of Medicine (A.M.A-O., S.H.C.), Box , University of Virginia Health System, Jefferson Park Avenue, Charlottesville, VA Received June 7, 2010; final revision received October 6, 2010, accepted November 16, Address correspondence to S.S.S.; ss2bp@virginia.edu None of the authors have identified a conflict of interest. SIR, 2011 J Vasc Interv Radiol 2011; 22: DOI: /j.jvir Balloon-occluded retrograde transvenous obliteration (BRTO) is an endovascular technique that was developed in Japan (1,2) as a therapeutic adjunct or alternative to transjugular intrahepatic portosystemic shunts (TIPS) in the management of gastric varices (GV). It is also an effective therapy for sclerosis of spontaneous portosystemic shunts complicated by hepatic encephalopathy. A BRTO procedure involves occlusion of outflow veins of a spontaneous portosystemic shunt, such as a gastrorenal shunt, using an occlusion balloon followed by transvenous catheter injection of a sclerosing agent directly into the varix (1 3). Critical to the procedure is the stagnation of the sclerosant within the varix or shunt without reflux of the agent into either the portal or systemic vasculature, which might result in serious complications. To avoid these events, occlusion balloons are strategically placed to modulate the flow within the varix or shunt. Additionally, microcatheters and embolization coils are adjunctive tools used to administer the sclerosant in high concentration within the varix and to prevent flow of the sclerosant to nontarget vascular beds.

2 310 Bleeding Gastric Varices Sabri et al JVIR The procedural details and outcomes of BRTO are well described in the literature (1 12). Ethanolamine oleate (EO) has been used as the sclerosing agent in the majority of these reports. However, EO is not readily available in the United States in the desirable concentrations described in the literature. The purpose of this study is to describe our initial experience with BRTO using sodium tetradecyl sulfate (STS) foam as an alternative sclerosing agent and evaluate its safety and efficacy in obliterating gastric varices. MATERIALS AND METHODS A retrospective review of consecutive patients with bleeding gastric varices treated with BRTO using STS foam at a single institution was performed between August 1, 2007 and March 1, 2010 using the procedural database Hi-IQ (ConexSys, Albion, Rhode Island). All study subjects had clinical and endoscopic evidence of gastric variceal bleeding and had a patent gastrorenal shunt on preprocedure contrast enhanced computed tomography (CT) or magnetic resonance (MR) imaging study. The BRTO procedure was performed within 2 months of the index gastrointestinal bleeding. All patients were hemodynamically stable at the time of the procedure. Institutional human investigation review board exemption was obtained for this retrospective review. Electronic medical records were evaluated for patient demographics, endoscopic findings, BRTO procedure information, and clinical and imaging follow-up. Procedural complications were also recorded. The procedure was performed under moderate sedation or general anesthesia, by obtaining access into the right femoral or internal jugular veins using standard angiographic technique and placement of a 6 12-F sheath. Access into the gastrorenal shunt was achieved by selective catheterization of the left renal vein using a 5-F diagnostic catheter (Cobra; Angiodynamics, Queensbury, New York). The diagnostic catheter was then exchanged for an angled tip catheter (Slip-cath; Cook Inc, Bloomington, Indiana), which was used to select the shunt. Alternatively a 5-F Simmons II catheter (Angiodynamics) was used to select the left renal vein and was pulled back into the shunt. Next, a inch stiff wire (Rosen, Angiodynamics, or TAD II; Mallinckrodt Inc., St Louis, Missouri) was then advanced into the shunt followed by an occlusion balloon catheter with diameters ranging from mm. The diameter of the balloon was chosen to occlude the draining gastrorenal shunt. The access sheath was usually positioned in the inferior vena cava or the renal vein. Several occlusion balloons were used: the Python (Applied Medical, Rancho Santa Margarita, California), the Equalizer (Boston Scientific, Natick, Massachusetts), Standard Occlusion Balloon Catheters (Boston Scientific), Flow Directed Occlusion Balloon Catheters (Cook Inc), and the Coda (Cook Inc). Retrograde balloon occlusion venography was then performed to define the type of varix/varices and the anatomy of the venous drainage. The cases were classified according to the venous drainage pattern into type A, B, or C (Fig 1) (4,5). We did not include any type D drainage patterns in this series, as the presence of a gastrorenal shunt was a prerequisite. A 3-F microcathter (Rapid transit; Codman & Shurtleff, Inc, Raynham, Massachusetts) was advanced through the occlusion balloon as deep as possible into the varix. The STS (Sotradecol, Angiodynamics) foam mixture was made using the Tessari method (13) with a three-way stopcock and a combination of the following agents in a 3:2:1 ratio of air or CO 2 : 3% STS: Lipiodol (Ethiodol; Savage Laboratories, Melville, New York) being the most common mixture used. This sclerosing mixture was then infused through the microcatheter with the goal of filling of the full extent of the varix. The embolization end point was minimal filling of the afferent portal vein branch. Cone beam CT (Dyna CT; Siemens Medical, Malvern, Pennsylvania) was used when necessary to document filling of the entire varix with sclerosant (Fig 2). In some type B and the majority of C patients, when full opacification of the varices was not achieved, the leaking collateral veins, such as the inferior phrenic or paravertebral veins, were occluded using coils (Nester or Tornado coils, Cook Inc) or gelfoam pledgets via a selectively positioned microcatheter in an effort to minimize distribution of the sclerosing mixture into the nontarget portal or systemic vasculature (Fig 3). For type C cases with prominent secondary shunts (eg, gastropericardiophrenic and gastrorenal shunts in the same patient), an additional occlusion balloon, usually placed from the jugular venous approach, was used to occlude the second shunt and control the distribution of the sclerosing mixture. The occlusion balloon(s) remained inflated in place for a minimum of 4 hours and a maximum of 24 hours. For the first five cases in this series, the balloons were left overnight and deflated under fluoroscopy the next day. For the subsequent cases, the protocol was changed to leaving the balloons inflated for 4 hours. Technical success was defined as successful placement of the occlusion balloon in the gastrorenal shunt and administration of the sclerosant mixture into the gastric varices. Follow-up evaluation of the gastric varices was obtained with endoscopic ultrasound (EUS), contrast-enhanced CT, and/or MR imaging before discharge. Patients were then evaluated clinically and with EUS and/or endoscopy at 3 6-month intervals. Obliteration of varices was defined as absence of residual enhancement within the gastric varices on follow-up CT or MR imaging or absence of flow on Doppler EUS and was classified as complete, partial, or failed obliteration. RESULTS We performed BRTO in 22 patients with the diagnosis of liver cirrhosis (11 men and 11 women) with a mean age of 52 years (range, years). Pre-procedure MR imaging or CT imaging showed a patent gastrorenal shunt (GRS) in all patients, with a mean diameter of the communicating

3 Volume 22 Number 3 March Figure 1. Classification of venous outflow types based on retrograde balloon occluded venogram of the gastrorenal shunt. vein of 14.5 mm (range, 9 20 mm). Two patients had functioning existing TIPS. Patients were classified as either type A (n 10), type B (n 7), or type C (n 5) according to their variceal anatomy (Table 1). Technical success was achieved in 20 of 22 (91%) patients. One failure was secondary to an inability to catheterize and occlude the shunt because of to extreme tortuosity of the venous anatomy and extravasation of contrast. In the other technical failure, the occlusion balloon ruptured immediately after completion of sclerosant administration. Further attempts to administer sclerosant were unsuccessful, as extravasation of contrast developed during exchange of the balloon. Complications occurred in 14% (3 of 22) of the patients. One patient was found to have partial thrombosis of the main portal vein at the time of predischarge imaging. This partial portal vein thrombosis was asymptomatic and likely occurred as a result of flow of some of the sclerosing mixture into the portal vein, as Lipiodol was also seen in some of the small portal venules. The patient remains symptom free at 9 months of follow-up. One patient had transient methicillin-susceptible Staphylococcus aureus bacteremia that resolved with antibiotic therapy. The third patient had a symptomatic pulmonary embolism 2 weeks after the procedure. The patient was found to have upper extremity deep vein thrombosis by ultrasound scan, presumably related to central line placement. Of note, no radioopaque material was present within the pulmonary circulation to indicate embolization of the sclerosant. There were no procedural-related mortalities. The overall mean dosage of STS used was 300 mg (range, mg) with a mean volume of the STS instilled of 10 ml (1 20 ml). The mean total volume of the sclerosing mixture used was 34.1 ml (range, ml). Nine patients (41%) required adjunctive embolization (coils/gelfoam) of secondary draining veins. One patient required double balloon occlusion of the gastrorenal shunt and the gastropericardiophrenic shunt. Follow-up imaging (CT, MR imaging, or endoscopic ultrasound scan) was available for 18 of 20 (90%) of the patients who had technically successful procedures at a mean follow-up of 89 days (range, days) after the

4 312 Bleeding Gastric Varices Sabri et al JVIR Figure 2. Type A venous outflow. (a) Retrograde balloon-occluded venogram of the gastrorenal shunt with the occlusion balloon inflated (arrowheads). A type A venous outflow with opacification of the gastric varices and the afferent portal branch (arrow) is shown. (b) After administration of the sclerosant mixture, the end point of embolization shows minimal filling of the afferent portal branch (arrow). BRTO. Complete obliteration of GV was noted in 15 of 18 (83%) patients. Three of 18 (17%) patients had partial obliteration of their GV. Of these three partial obliteration patients, one had successful repeat BRTO, one was treated with endoscopic glue therapy, and one was lost to followup. Including the two cases of technical failure, a secondary procedure (endoscopic glue therapy or a repeat BRTO was required in four of 22 (18%) cases. There were no cases of recurrent variceal bleeding, with a mean clinical follow-up period of 130 days (range, 3 510). Including the one patient who underwent a repeat BRTO procedure, complete obliteration was noted in 16 of 18 (89%) patients at the time of their last follow-up (Fig 4). DISCUSSION Bleeding GV are associated with a higher mortality rate than that of esophageal variceal bleeding (14 16). Therefore, management of GV is often difficult and requires a collaborative, multidisciplinary approach to obtain the best patient outcomes. A variety of treatment options, such as pharmacotherapy, balloon tamponade, endoscopic procedures, endovascular treatment, and surgery have all been performed with varying individual success rates. TIPS has been widely used to treat bleeding esophageal and GV with good initial control of bleeding. (17 22). However, when reviewed separately, GV appear to have higher rebleeding rates compared with those of esophageal varices. Furthermore, when correlating portosystemic gradients, it has been noted that GV bleeding tends to occur at lower portosystemic gradients compared with esophageal varices. The reason GV bleed at lower portosystemic gradients is in part explained by their overall larger diameter compared with that of esophageal varices. The larger diameter results in greater wall tension for any given pressure in accordance with Laplace s law and may potentiate bleeding (19,22,23). In fact, patients with large GV tend to have lower portosystemic gradients because the majority drain through large spontaneous gastrorenal shunts, which decompresses the portal system. BRTO has the advantage of directly obliterating GV regardless of portosystemic gradients. Furthermore, BRTO may be performed in patients that may otherwise not tolerate TIPS because of hepatic encephalopathy and poor liver function. Endoscopic N-butyl-2-cyanoacrylate injection (EBC) is an effective method in obliterating GV. However, rebleeding rates have been reported to be as high as 40 % (23 26). A recent prospective, randomized controlled trial by Lo et al (27) compared the efficacies and complications of EBC and TIPS in the prevention of GV rebleeding. This study found that TIPS is more effective than EBC in preventing rebleeding from GV, with a similar survival rate and frequency of complications. Hong et al (28) compared outcomes of EBC with those of BRTO and showed a higher initial technical success

5 Volume 22 Number 3 March Figure 3. Type B venous outflow. (a) With the occlusion balloon inflated (arrowheads), retrograde balloon-occluded venogram of the gastrorenal shunt shows a type B venous outflow with partial opacification of the shunt as well as multiple draining veins (white arrows) including the inferior phrenic vein (black arrows). (b) Opacification of the gastric varices (black arrow) and the afferent portal branch (arrowheads) after coil embolization of collateral veins (white arrow). (c) Preprocedure contrast-enhanced MR image shows enhancement of the gastric varices (arrows). (d) Intraprocedure cone beam CT (Dyna CT) during retrograde venography shows opacification of the gastric varices (arrows). (e) Follow-up contrast-enhanced MR imaging 3 months after the procedure shows complete obliteration of the gastric varices (arrows). rate for EBC (100% vs 77%, respectively). However, the rebleeding rate was 71% for the EBC group compared with 15% for the BRTO group. BRTO was used as a salvage procedure in the rebleeding patients in this study. Based on the experience at our Institution (initial technical success rate of 91% and a complete obliteration of GV of 83% in technically successful patients at follow-up after the initial BRTO), we have adopted the algorithm of per-

6 314 Bleeding Gastric Varices Sabri et al JVIR Table 1. Gastric Varices Classification and Procedure Outcomes GV Type N Success (n) Additional Embolization/ Occlusion Balloon Needed A NA B 7 6 Coil embolization gelfoam (5) Gelfoam only (1) C 5 4 Coil embolization (3) Additional occlusion balloon (1) Note. NA not applicable. forming BRTO first for bleeding GV. If endoscopic ultrasound scan shows any residual flow in the GV, then EBC or a repeat BRTO is performed. This secondary procedure was required in four of 22 (18%) of cases. None of the patients included in this study that were available for follow-up (one patient was lost to follow-up) experienced rebleeding. Ethanolamine Oleate (EO, Oldamin; Grelan Pharmaceutical, Tokyo, Japan) is the original agent used for this procedure and is the agent of choice in Asia (1 12). Five percent EO is the most common concentration used and consists of a mixture of 10% EO and the same dose of a contrast medium (3,5,6). EO causes hemolysis in the blood vessels. As a result, free hemoglobin is released, which may cause renal tubular disturbances and acute renal failure. To prevent renal insufficiency, 4,000 U of haptoglobin (Green Cross, Osaka, Japan) is administered intravenously during the BRTO to bind with the circulating free hemoglobin to minimize its nephrotoxic effects. Other reported complications associated with the use of EO include cardiogenic shock, pulmonary edema, and disseminated intravascular coagulation (3,5,6). Therefore, some investigators recommend limiting the use of EO to a volume of 40 ml per procedure (5). One other limiting factor for using EO in the United States is the lack of experience with this agent in other vascular beds. The largest obstruction to use of this agent in the United States is its lack of availability in the desirable concentrations. Sodium tetradecyl sulphate has been used widely for sclerotherapy of superficial lower extremity varicosities in both the liquid and foam forms (29,30). It has also been utilized as a foam sclerosant in treating male varicoceles, pelvic congestion syndromes, and venous malformations (31 34). The STS foam has the potential advantage of minimizing the dose of the sclerosant, especially in large varicose veins. In this study, the mean total volume of sclerosing mixture used was 34.1 ml (range, ml) and the mean volume of 3% STS was 10 ml (1 20 ml). These volumes of the sclerosant and its mixtures compares favorably to the reported volumes of EO in some of the larger reported series (means of ml) (3,10). The use of a lower dose of sclerosant has the potential advantage of lowering the systemic effects, such as hemolysis and renal failure, without affecting the technical success or obliteration rate. In fact, the obliteration rate of 89% in the current series using STS is comparable with obliteration rates reported in the literature using EO ranging between 87% and 100%. Table 2 summarizes outcomes of large series using EO as a sclerosant compared with the current series. The STS foam also provides the potential advantage of better contact with the variceal wall when compared with liquid agents (29). In treating lower extremity varicose veins, foam sclerotherapy was found to be far more effective than liquid sclerotherapy by creating air bubbles that Figure 4. Summary of BRTO outcomes.

7 Volume 22 Number 3 March Table 2. Outcomes of Studies Utilizing BRTO to Treat Gastric Varices Technical Rebleeding Complete Study Patients (n) Success (%) Rate (%) Obliteration Rate (%) Cho et al (7) Hiraga et al (3) Kitamoto et al (10) Arai et al (8) Ninoi et al (9) Kanagawa et al (1) Sonomura et al (11) Current series not only displace the blood volume but also provide a larger surface area of the sclerosant to contact the venous endothelium (30). In-vivo studies have found the pathologic damage of the foam to be rapid with complete damage of the endothelium within the first 2 minutes of contact with the foam, followed by intimal edema, progressive intimal separation from the tunica media, and formation of microthrombi in the successive 30 minutes (35). Sotradecol is available in two different concentrations (1% and 3%). In this study, 3% Sotradecol was used to provide the highest dose possible in the markedly dilated varices, even though one study suggested that there is no added benefit from utilizing 3% polidocanol foam compared with 1% polidocanol foam (30). In our series, 3% Sotradecol was mixed with gas (air or CO 2 ) to provide foam consistency. Lipiodol was added to aid in visualization of the sclerosant mixture. The STS was mixed with lipiodol and gas (air or CO 2 )ina ratio of 2 ml STS to 1 ml Lipiodol to 3 ml air/co 2. Although most cases were done using room air, there remains the concern that room air can potentially embolize either to the lungs or the systemic arterial circulation via a patent foramen ovale as it comes out of solution (36,37). The duration of balloon inflation was modified after the first five cases from 24 hours to 4 hours, because leaving the balloon in place for such a long time carries the potential risks of increased access site bleeding, higher infection rates, and patient inconvenience. In addition, there are logistical and cost concerns from having the patients stay overnight in a monitored bed. In summary, BRTO utilizing STS foam appears effective in obliterating bleeding GV with good short-term outcomes. Further larger studies are required to confirm its use and evaluate the long-term outcomes of BRTO of GV utilizing this sclerosant. REFERENCES 1. Kanagawa H, Mima S, Kouyama H, Gotoh K, Uchida T, Okuda K. Treatment of gastric fundal varices by balloon-occluded retrograde transvenous obliteration. J Gastroenterol Hepatol 1996; 11: Chikamori F, Shibuya S, Takase Y, Ozaki A, Fukao K. Transjugular retrograde obliteration for gastric varices. Abdom Imaging 1996; 21: Hiraga N, Aikata H, Takaki S, et al. 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8 316 Bleeding Gastric Varices Sabri et al JVIR 20. Zhuang ZW, Teng GJ, Jeffery RF, et al. Long-term results and quality of life in patients treated with transjugular intrahepatic portosystemic shunts. Am J Roentgenol 2002; 179: Boyer TD, Haskal ZJ, American Association for the Study of Liver Diseases. The role of transjugular intrahepatic portosystemic shunt in the management of portal hypertension. Hepatology 2005; 41: Jalan R, Hayes PC. UK guidelines on the management of variceal haemorrhage in cirrhotic patients. British Society of Gastroenterology. Gut 2000;46: Abi-Jaoudeh N, Matsumoto AH, Angle JF, et al. TIPS rebleeding rates for different subtypes of varices in the era of covered stents. J Vasc Intervent Radiol 2008; 19 (Suppl 1):S77 S Soehendra N, Nam VC, Grimm H, Kemperneers I. Endoscopic obliteration of large esophageal gastric varices with bucrylate. Endoscopy 1986; 18: Hwang YH, Yeh HZ, Chen GH, et al. Endoscopic hemostasis of bleeding gastric varices by N-butyl-2-cyanoacrylate (Histoacryl) injection: longterm efficacy and safety. Gastrointest Endosc 2000; 52: Oho K, Iwao T, Sumino M, et al. Ethanolamine oleate versus butyl cyanoacrylate for bleeding gastric varices: a nonrandomized study. Endoscopy 1995; 27: Lo GH, Liang HL, Chen WC, et al. A prospective randomized controlled trial of transjugular intrahepatic portosystemic shunt versus cyanoacrylate injection in the prevention of gastric variceal rebleeding. Endoscopy 2007; 39: Hong CH, Kim HJ, Park JH, et al. Treatment of patients with gastric variceal hemorrhage: Endoscopic N-butyl-2-cyanoacrylate injection versus balloon-occluded retrograde transvenous obliteration. J Gastroenterol Hepatol 2009; 24: Demagny A. Comparative study into the efficacy of a sclerosant product in the form of liquid or foam in echo-guided of arches of the long and short saphenous veins. Phlebologie 2002; 55: Smith C. Sclerotherapy and foam sclerotherapy for varicose veins. Phlebology 2009; 24: Gandini R, Chiocchi M, Konda D, et al. Transcatheter foam sclerotherapy of symptomatic female varicocele with sodium-tetradecyl-sulfate foam. Cardiovasc Intervent Radiol 2008; 31: Gandini R, Konda D, Reale CA, et al. Male varicocele: transcatheter foam sclerotherapy with sodium tetradecyl sulfate outcome in 244 patients. Radiology 2008; 246: Tan KT, Kirby J, Rajan DK, Hayeems E, Beecroft JR. Percutaneous sodium tetradecyl sulfate sclerotherapy for peripheral venous vascular malformations: a single-center experience. J Vasc Interv Radiol 2007; 18: Yamaki T, Nozaki M, Sakurai H, Takeuchi M, Soejima K, Kono T. Prospective randomized efficacy of ultrasound-guided foam sclerotherapy compared with ultrasound-guided liquid sclerotherapy in the treatment of symptomatic venous malformations. J Vasc Surg 2008; 47: Orsini C, Brotto M. Immediate pathologic effects on the vein wall of foam sclerotherapy. Dermatol Surg 2007; 33: Ceulen RP, Sommer A, Vernooy K. Microembolism during foam sclerotherapy of varicose veins. N Engl J Med 2008; 358: Forlee MV, Grouden M, Moore DJ, Shanik G. Stroke after varicose vein foam injection sclerotherapy. J Vasc Surg 2006; 43: CME TEST QUESTIONS Examination available at The CME questions in this issue are derived from the article Bleeding Gastric Varices Obliteration with Balloonoccluded Retrograde Transvenous Obliteration Using Sodium Tetradecyl Sulfate Foam by Sabri et al. 1. Regarding venous drainage patterns of gastric varices in this study: a) Type A were the most common type encountered and were all successfully treated. b) Type B all had shunts that required additional embolization before sclerosant administration. c) Type C all required placement of multiple occlusion balloons. d) Type D were the least common encountered and were the most difficult to treat. 2. In place of a sclerosing solution of ethanolamine oleate and contrast medium, the authors created a sclerosing foam mixture: a) Using the same contrast medium for visualization of the mixture. b) In a 3:2:1 ratio of gas:sclerosant:contrast. c) With 5% sodium tetradecyl sulfate solution. d) Which was infused directly through the occlusion balloon. 3. In this study, the occlusion balloon was: a) Left inflated for 20 minutes in most subjects. b) Removed 30 minutes after aspirating the sclerosing mixture. c) Left inflated for 4 hours in most subjects. d) Kept in place at least 24 hours to optimize effect. 4. The authors note all of the following EXCEPT: a) A technical challenge was the inability to catheterize a shunt due to extreme vessel tortuosity. b) Procedure-related complications encountered included symptomatic portal vein thrombosis. c) Reduced volume of sodium tetradecyl sulfate, compared to the volume of ethanolamine oleate previously reported, may help reduce sclerosantrelated systemic effects. d) One reason for reduction of balloon inflation time was concern for infectious complications.