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Semin intervent Radiol 2012; 29(02): 118-128
DOI: 10.1055/s-0032-1312573
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Balloon-Occluded Retrograde Transvenous Obliteration of Gastric Varices: Concept, Basic Techniques, and Outcomes

Wael E. A. Saad
1   Division of Vascular Interventional Radiology, Department of Radiology and Medical Imaging, University of Virginia Health System, Charlottesville, Virginia
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Publication Date:
14 June 2012 (online)

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Abstract

Patients with gastric variceal bleeding require a multidisciplinary team approach including hepatologists, endoscopists, diagnostic radiologists, and interventional radiologists. Upper gastrointestinal endoscopy is the first-line diagnostic and management tool for bleeding gastric varices, as it is in all upper gastrointestinal bleeding scenarios. In the United States when endoscopy fails to control gastric variceal bleeding, a transjugular intrahepatic portosystemic shunt (TIPS) traditionally is performed along the classic teachings of decompressing the portal circulation. However, TIPS has not shown the same effectiveness in controlling gastric variceal bleeding that it has with esophageal variceal bleeding. For the past 2 decades, the balloon-occluded retrograde transvenous obliteration (BRTO) procedure has become common practice in Asia for the management of gastric varices. BRTO is gaining popularity in the United States. It has been shown to be effective in controlling gastric variceal bleeding with low rebleed rates. BRTO has many advantages over TIPS in that it is less invasive and can be performed on patients with poor hepatic reserve and those with encephalopathy (and may even improve both). However, its by-product is occlusion of a spontaneous hepatofugal (TIPS equivalent) shunt, and thus it is contradictory to the traditional American doctrine of portal decompression. Indeed, BRTO causes an increase in portal hypertension, with potential aggravation of esophageal varices and ascites. This article discusses the concept, technique, and outcomes of BRTO within the broader management of gastric varices.

Keywords

BRTO - transvenous obliteration - gastric - varices - TIPS - portal hypertension
 

  • References

  • 1 Al-Osaimi AMS, Caldwell SH. Medical and endoscopic management of gastric varices. Semin Intervent Radiol 2011; 28: 273-282
    Article in Thieme ConnectPubMedGoogle Scholar
  • 2 Al-Osaimi AMS, Sabri SS, Caldwell SH. Balloon-occluded retrograde transvenous obliteration (BRTO): preprocedural evaluation and imaging. Semin Intervent Radiol 2011; 28: 288-295
    Article in Thieme ConnectPubMedGoogle Scholar
  • 3 Saad WEA, Darcy MD. Transjugular intrahepatic portosystemic shunt (TIPS) versus balloon-occluded retrograde transvenous obliteration (BRTO) for the management of gastric varices. Semin Intervent Radiol 2011; 28: 339-349
    Article in Thieme ConnectPubMedGoogle Scholar
  • 4 Saad WEA, Sabri SS. Balloon-occluded retrograde transvenous obliteration (BRTO): technical results and outcomes. Semin Intervent Radiol 2011; 28: 333-338
    Article in Thieme ConnectPubMedGoogle Scholar
  • 5 Saad WEA. The history and evolution of balloon-occluded retrograde transvenous obliteration (BRTO): from the United States to Japan and back. Semin Intervent Radiol 2011; 28: 283-287
    Article in Thieme ConnectPubMedGoogle Scholar
  • 6 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 (1) 51-58
    CrossrefPubMedGoogle Scholar
  • 7 Kiyosue H, Mori H, Matsumoto S, Yamada Y, Hori Y, Okino Y. Transcatheter obliteration of gastric varices. Part 1. Anatomic classification. Radiographics 2003; 23 (4) 911-920
    CrossrefPubMedGoogle Scholar
  • 8 Kiyosue H, Mori H, Matsumoto S, Yamada Y, Hori Y, Okino Y. Transcatheter obliteration of gastric varices: Part 2. Strategy and techniques based on hemodynamic features. Radiographics 2003; 23 (4) 921-937 ; discussion 937
    CrossrefPubMedGoogle Scholar
  • 9 Yamagami T, Kato T, Hirota T, Yoshimatsu R, Matsumoto T, Nishimura T. Infusion of 50% glucose solution before injection of ethanolamine oleate during balloon-occluded retrograde transvenous obliteration. Australas Radiol 2007; 51 (4) 334-338
    CrossrefPubMedGoogle Scholar
  • 10 Kitamoto M, Imamura M, Kamada K , et al. Balloon-occluded retrograde transvenous obliteration of gastric fundal varices with hemorrhage. AJR Am J Roentgenol 2002; 178 (5) 1167-1174
    CrossrefPubMedGoogle Scholar
  • 11 Ninoi T, Nakamura K, Kaminou T , et al. TIPS versus transcatheter sclerotherapy for gastric varices. AJR Am J Roentgenol 2004; 183 (2) 369-376
    CrossrefPubMedGoogle Scholar
  • 12 Ninoi T, Nishida N, Kaminou T , et al. Balloon-occluded retrograde transvenous obliteration of gastric varices with gastrorenal shunt: long-term follow-up in 78 patients. AJR Am J Roentgenol 2005; 184 (4) 1340-1346
    CrossrefPubMedGoogle Scholar
  • 13 Akahoshi T, Hashizume M, Tomikawa M , et al. Long-term results of balloon-occluded retrograde transvenous obliteration for gastric variceal bleeding and risky gastric varices: a 10-year experience. J Gastroenterol Hepatol 2008; 23 (11) 1702-1709
    CrossrefPubMedGoogle Scholar
  • 14 Fukuda T, Hirota S, Sugimura K. Long-term results of balloon-occluded retrograde transvenous obliteration for the treatment of gastric varices and hepatic encephalopathy. J Vasc Interv Radiol 2001; 12 (3) 327-336
    CrossrefPubMedGoogle Scholar
  • 15 Sonomura T, Sato M, Kishi K , et al. Balloon-occluded retrograde transvenous obliteration for gastric varices: a feasibility study. Cardiovasc Intervent Radiol 1998; 21 (1) 27-30
    CrossrefPubMedGoogle Scholar
  • 16 Kiyosue H, Matsumoto S, Onishi R , et al. Balloon-occluded retrograde transvenous obliteration (B-RTO) for gastric varices: therapeutic results and problems [in Japanese]. Nippon Igaku Hoshasen Gakkai Zasshi 1999; 59 (1) 12-19
    PubMedGoogle Scholar
  • 17 Koito K, Namieno T, Nagakawa T, Morita K. Balloon-occluded retrograde transvenous obliteration for gastric varices with gastrorenal or gastrocaval collaterals. AJR Am J Roentgenol 1996; 167 (5) 1317-1320
    CrossrefPubMedGoogle Scholar
  • 18 Chikamori F, Kuniyoshi N, Kawashima T, Takase Y. Gastric varices with gastrorenal shunt: combined therapy using transjugular retrograde obliteration and partial splenic embolization. AJR Am J Roentgenol 2008; 191 (2) 555-559
    CrossrefPubMedGoogle Scholar
  • 19 Kumamoto M, Toyonaga A, Inoue H , et al. Long-term results of balloon-occluded retrograde transvenous obliteration for gastric fundal varices: hepatic deterioration links to portosystemic shunt syndrome. J Gastroenterol Hepatol 2010; 25 (6) 1129-1135
    CrossrefPubMedGoogle Scholar
  • 20 Chikamori F, Kuniyoshi N, Shibuya S, Takase Y. Transjugular retrograde obliteration for chronic portosystemic encephalopathy. Abdom Imaging 2000; 25 (6) 567-571
    CrossrefPubMedGoogle Scholar
  • 21 Chikamori F, Kuniyoshi N, Shibuya S, Takase Y. Combination treatment of transjugular retrograde obliteration and endoscopic embolization for portosystemic encephalopathy with esophageal varices. Hepatogastroenterology 2004; 51 (59) 1379-1381
    PubMedGoogle Scholar
  • 22 Chikamori F, Kuniyoshi N, Shibuya S, Takase Y. Eight years of experience with transjugular retrograde obliteration for gastric varices with gastrorenal shunts. Surgery 2001; 129 (4) 414-420
    CrossrefPubMedGoogle Scholar
  • 23 Miyamoto Y, Oho K, Kumamoto M, Toyonaga A, Sata M. Balloon-occluded retrograde transvenous obliteration improves liver function in patients with cirrhosis and portal hypertension. J Gastroenterol Hepatol 2003; 18 (8) 934-942
    CrossrefPubMedGoogle Scholar
  • 24 Hirota S, Matsumoto S, Tomita M, Sako M, Kono M. Retrograde transvenous obliteration of gastric varices. Radiology 1999; 211 (2) 349-356
    CrossrefPubMedGoogle Scholar
  • 25 Sugimori K, Morimoto M, Shirato K, Kokawa A, Tomita N, Numata K , et al. Retrograde transvenous obliteration of gastric varices associated with large collateral veins or a large gastrorenal shunt. J Vasc Intervent Radiol 2005; 16: 113-118
    CrossrefPubMedGoogle Scholar
  • 26 Fukuda T, Hirota S, Matsumoto S , et al. Application of balloon-occluded retrograde transvenous obliteration to gastric varices complicating refractory ascites. Cardiovasc Intervent Radiol 2004; 27 (1) 64-67
    PubMedGoogle Scholar
  • 27 Shimoda R, Horiuchi K, Hagiwara S , et al. Short-term complications of retrograde transvenous obliteration of gastric varices in patients with portal hypertension: effects of obliteration of major portosystemic shunts. Abdom Imaging 2005; 30 (3) 306-313
    CrossrefPubMedGoogle Scholar
  • 28 Takuma Y, Nouso K, Makino Y, Saito S, Shiratori Y. Prophylactic balloon-occluded retrograde transvenous obliteration for gastric varices in compensated cirrhosis. Clin Gastroenterol Hepatol 2005; 3 (12) 1245-1252
    CrossrefPubMedGoogle Scholar
  • 29 Arai H, Abe T, Takagi H, Mori M. Efficacy of balloon-occluded retrograde transvenous obliteration, percutaneous transhepatic obliteration and combined techniques for the management of gastric fundal varices. World J Gastroenterol 2006; 12 (24) 3866-3873
    PubMedGoogle Scholar
  • 30 Arai H, Abe T, Shimoda R, Takagi H, Yamada T, Mori M. Emergency balloon-occluded retrograde transvenous obliteration for gastric varices. J Gastroenterol 2005; 40 (10) 964-971
    CrossrefPubMedGoogle Scholar
  • 31 Park SJ, Chung JW, Kim H-C, Jae HJ, Park JH. The prevalence, risk factors, and clinical outcome of balloon rupture in balloon-occluded retrograde transvenous obliteration of gastric varices. J Vasc Interv Radiol 2010; 21 (4) 503-507
    CrossrefPubMedGoogle Scholar
  • 32 Hong CH, Kim HJ, Park JH , et al. Treatment of patients with gastric variceal hemorrhage: endoscopic N-butyl-2cyanoacrylate injection versus balloon-occluded retrograde transvenous obliteration. Hepatology 2009; 24: 372-378
    PubMedGoogle Scholar
  • 33 Park KS, Kim YH, Choi JS , et al. Therapeutic efficacy of balloon-occluded retrograde transvenous obliteration in patients with gastric variceal bleeding [in Korean]. Korean J Gastroenterol 2006; 47 (5) 370-378
    PubMedGoogle Scholar
  • 34 Kim ES, Park SY, Kwon KT , et al. The clinical usefulness of balloon occluded retrograde transvenous obliteration in gastric variceal bleeding [in Korean]. Taehan Kan Hakhoe Chi 2003; 9 (4) 315-323
    PubMedGoogle Scholar
  • 35 Cho SK, Shin SW, Lee IH , et al. Balloon-occluded retrograde transvenous obliteration of gastric varices: outcomes and complications in 49 patients. AJR Am J Roentgenol 2007; 189 (6) W365-72
    PubMedGoogle Scholar
  • 36 Choi YH, Yoon CJ, Park JH, Chung JW, Kwon JW, Choi GM. Balloon-occluded retrograde transvenous obliteration for gastric variceal bleeding: its feasibility compared with transjugular intrahepatic portosystemic shunt. Korean J Radiol 2003; 4 (2) 109-116
    CrossrefPubMedGoogle Scholar
  • 37 Olson E, Yune HY, Klatte EC. Transrenal-vein reflux ethanol sclerosis of gastroesophageal varices. AJR Am J Roentgenol 1984; 143 (3) 627-628
    CrossrefPubMedGoogle Scholar
  • 38 Kravetz D, Bosch J, Arderiu M, Pilar Pizcueta M, Rodés J. Hemodynamic effects of blood volume restitution following a hemorrhage in rats with portal hypertension due to cirrhosis of the liver: influence of the extent of portal-systemic shunting. Hepatology 1989; 9 (6) 808-814
    CrossrefPubMedGoogle Scholar
  • 39 Castañeda B, Morales J, Lionetti R , et al. Effects of blood volume restitution following a portal hypertensive-related bleeding in anesthetized cirrhotic rats. Hepatology 2001; 33 (4) 821-825
    CrossrefPubMedGoogle Scholar
  • 40 Villanueva C, Ortiz J, Miñana J , et al. Somatostatin treatment and risk stratification by continuous portal pressure monitoring during acute variceal bleeding. Gastroenterology 2001; 121 (1) 110-117
    CrossrefPubMedGoogle Scholar
  • 41 de Franchis R. Evolving consensus in portal hypertension. Report of the Baveno IV consensus workshop on methodology of diagnosis and therapy in portal hypertension. J Hepatol 2005; 43 (1) 167-176
    CrossrefPubMedGoogle Scholar
  • 42 Gabriel DA, Li X, Monroe III DMIII, Roberts HR. Recombinant human factor VIIa (rFVIIa) can activate factor FIX on activated platelets. J Thromb Haemost 2004; 2 (10) 1816-1822
    CrossrefPubMedGoogle Scholar
  • 43 García-Pagán JC, Caca K, Bureau C , et al; Early TIPS (Transjugular Intrahepatic Portosystemic Shunt) Cooperative Study Group. Early use of TIPS in patients with cirrhosis and variceal bleeding. N Engl J Med 2010; 362 (25) 2370-2379
    CrossrefPubMedGoogle Scholar
  • 44 Garcia-Tsao G, Bosch J. Management of varices and variceal hemorrhage in cirrhosis. N Engl J Med 2010; 362 (9) 823-832
    CrossrefPubMedGoogle Scholar
  • 45 Araki T, Hori M, Motosugi U , et al. Can balloon-occluded retrograde transvenous obliteration be performed for gastric varices without gastrorenal shunts?. J Vasc Interv Radiol 2010; 21 (5) 663-670
    CrossrefPubMedGoogle Scholar
  • 46 Ota K, Okazaki M, Higashihara H , et al. Combination of transileocolic vein obliteration and balloon-occluded retrograde transvenous obliteration is effective for ruptured duodenal varices. J Gastroenterol 1999; 34 (6) 694-699
    CrossrefPubMedGoogle Scholar
  • 47 Ono S, Irie T, Kuramochi M, Kamoshida T, Hirai S, Oka Y. Successful treatment of mesenteric varices with balloon-occluded retrograde transvenous obliteration via an abdominal wall vein. J Vasc Interv Radiol 2007; 18 (8) 1033-1035
    CrossrefPubMedGoogle Scholar
  • 48 Ibukuro K, Sugihara T, Tanaka R , et al. Balloon-occluded retrograde transvenous obliteration (BRTO) for a direct shunt between the inferior mesenteric vein and the inferior vena cava in a patient with hepatic encephalopathy. J Vasc Interv Radiol 2007; 18 (1 Pt 1) 121-125
    CrossrefPubMedGoogle Scholar
  • 49 Kimura T, Haruta I, Isobe Y , et al. A novel therapeutic approach for rectal varices: a case report of rectal varices treated with double balloon-occluded embolotherapy. Am J Gastroenterol 1997; 92 (5) 883-886 S
    PubMedGoogle Scholar
  • 50 Akazawa Y, Murata I, Yamao T , et al. Successful management of bleeding duodenal varices by endoscopic variceal ligation and balloon-occluded retrograde transvenous obliteration. Gastrointest Endosc 2003; 58 (5) 794-797
    CrossrefPubMedGoogle Scholar
  • 51 Tominaga K, Montani A, Kuga T , et al. Combined balloon-occluded embolization for treatment of concurrent duodenal, gastric, and esophageal varices: a case report. Gastrointest Endosc 2001; 53 (6) 665-668
    CrossrefPubMedGoogle Scholar
  • 52 Onozato Y, Kakizaki S, Iizuka H , et al. Ectopic varices rupture in the gastroduodenal anastomosis successfully treated with N-butyl-2-cyanoacrylate injection. Acta Med Okayama 2007; 61 (6) 361-365
    PubMedGoogle Scholar
  • 53 Zamora CA, Sugimoto K, Tsurusaki M , et al. Endovascular obliteration of bleeding duodenal varices in patients with liver cirrhosis. Eur Radiol 2006; 16 (1) 73-79
    CrossrefPubMedGoogle Scholar
  • 54 Haruta I, Isobe Y, Ueno E , et al. Balloon-occluded retrograde transvenous obliteration (BRTO), a promising nonsurgical therapy for ectopic varices: a case report of successful treatment of duodenal varices by BRTO. Am J Gastroenterol 1996; 91 (12) 2594-2597
    PubMedGoogle Scholar
  • 55 Ohta M, Yasumori K, Saku M, Saitsu H, Muranaka T, Yoshida K. Successful treatment of bleeding duodenal varices by balloon-occluded retrograde transvenous obliteration: a transjugular venous approach. Surgery 1999; 126 (3) 581-583
    CrossrefPubMedGoogle Scholar
  • 56 Sonomura T, Horihata K, Yamahara K , et al. Ruptured duodenal varices successfully treated with balloon-occluded retrograde transvenous obliteration: usefulness of microcatheters. AJR Am J Roentgenol 2003; 181 (3) 725-727
    CrossrefPubMedGoogle Scholar
  • 57 Tsurusaki M, Sugimoto K, Matsumoto S , et al. Bleeding duodenal varices successfully treated with balloon-occluded retrograde transvenous obliteration (B-RTO) assisted by CT during arterial portography. Cardiovasc Intervent Radiol 2006; 29 (6) 1148-1151
    CrossrefPubMedGoogle Scholar
  • 58 Hiraga N, Aikata H, Takaki S , et al. The long-term outcome of patients with bleeding gastric varices after balloon-occluded retrograde transvenous obliteration. J Gastroenterol 2007; 42 (8) 663-672
    CrossrefPubMedGoogle Scholar
  • 59 Funaro AH, Ring EJ, Freiman DB, Oleaga JA, Gordon RL. Transhepatic obliteration of esophageal varices using the stainless steel coil. AJR Am J Roentgenol 1979; 133 (6) 1123-1125
    CrossrefPubMedGoogle Scholar
  • 60 Scott J, Dick R, Long RG, Sherlock S. Percutaneous transhepatic obliteration of gastro-osephageal varices. Lancet 1976; 10: 53-55
    PubMedGoogle Scholar
  • 61 Lunderquist A, Simert G, Tylén U, Vang J. Follow-up of patients with portal hypertension and esophageal varices treated with percutaneous obliteration of gastric coronary vein. Radiology 1977; 122 (1) 59-63
    PubMedGoogle Scholar
  • 62 Lunderquist A, Vang J. Transhepatic catheterization and obliteration of the coronary vein in patients with portal hypertension and esophageal varices. N Engl J Med 1974; 291 (13) 646-649
    CrossrefPubMedGoogle Scholar
  • 63 Lunderquist A, Vang J. Sclerosing injection of esophageal varices through transhepatic selective catheterization of the gastric coronary vein. A preliminary report. Acta Radiol Diagn (Stockh) 1974; 15 (5) 546-550
    PubMedGoogle Scholar
  • 64 Fukuda T, Hirota S, Sugimoto K, Matsumoto S, Zamora CA, Sugimura K. “Downgrading” of gastric varices with multiple collateral veins in balloon-occluded retrograde transvenous obliteration. J Vasc Interv Radiol 2005; 16 (10) 1379-1383
    CrossrefPubMedGoogle Scholar
  • 65 Saad WEA, Sze D. Variations of balloon-occluded retrograde transvenous obliteration (BRTO): balloon-occluded antegrade transvenous obliteration (BATO) and alternative/adjunctive routes for BRTO. Semin Intervent Radiol 2011; 28: 314-324
    Article in Thieme ConnectPubMedGoogle Scholar
  • 66 Sabri SS, Saad WEA. Balloon-occluded retrograde transvenous obliteration (BRTO): technique and intraprocedural imaging. Semin Intervent Radiol 2011; 28: 303-313
    Article in Thieme ConnectPubMedGoogle Scholar
  • 67 Sabri S, Swee W, Turba UC, Saad WE, Park AW, Al-Osaimi AM , et al. Bleeding gastric varices obliteration with balloon-occluded retrograde transvenous obliteration (BRTO) utilizing sodium tetradecyl sulfate foam. J Vasc Interv Radiol 2011; 22: 309-316
    CrossrefPubMedGoogle Scholar
  • 68 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: 133-137
    PubMedGoogle Scholar
  • 69 Coleridge Smith P. Sclerotherapy and foam sclerotherapy for varicose veins. Phlebology 2009; 24 (6) 260-269
    CrossrefPubMedGoogle Scholar
  • 70 Gandini R, Chiocchi M, Konda D, Pampana E, Fabiano S, Simonetti G. Transcatheter foam sclerotherapy of symptomatic female varicocele with sodium-tetradecyl-sulfate foam. Cardiovasc Intervent Radiol 2008; 31 (4) 778-784
    CrossrefPubMedGoogle Scholar
  • 71 Gandini R, Konda D, Reale CA , et al. Male varicocele: transcatheter foam sclerotherapy with sodium tetradecyl sulfate–outcome in 244 patients. Radiology 2008; 246: 612-618
    CrossrefPubMedGoogle Scholar
  • 72 Tan KT, Kirby J, Rajan DK, Hayeems E, Beecroft JR, Simons ME. Percutaneous sodium tetradecyl sulfate sclerotherapy for peripheral venous vascular malformations: a single-center experience. J Vasc Interv Radiol 2007; 18 (3) 343-351
    CrossrefPubMedGoogle Scholar
  • 73 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 (3) 578-584
    CrossrefPubMedGoogle Scholar
  • 74 Matsumoto A, Hamamoto N, Nomura T , et al. Balloon-occluded retrograde transvenous obliteration of high risk gastric fundal varices. Am J Gastroenterol 1999; 94 (3) 643-649
    CrossrefPubMedGoogle Scholar
  • 75 Hayashi S, Saeki S, Hosoi H , et al. A clinical and portal hemodynamic analysis for obliteration of gastric-renal shunt communicated with gastric fundic varice. s [in Japanese]. Nippon Shokakibyo Gakkai Zasshi 1998; 95 (7) 755-763
    PubMedGoogle Scholar
  • 76 Tanihata H, Minamiguchi H, Sato M , et al. Changes in portal systemic pressure gradient after balloon-occluded retrograde transvenous obliteration of gastric varices and aggravation of esophageal varices. Cardiovasc Intervent Radiol 2009; 32 (6) 1209-1216
    CrossrefPubMedGoogle Scholar
  • 77 Choi YS, Lee JH, Sinn DH , et al. Effect of balloon-occluded retrograde transvenous obliteration on the natural history of coexisting esophageal varices. J Clin Gastroenterol 2008; 42 (9) 974-979
    CrossrefPubMedGoogle Scholar
  • 78 Nakamura S, Torii N, Yatsuji S , et al. Long-term follow up of esophageal varices after balloon-occluded retrograde transvenous obliteration for gastric varices. Hepatol Res 2008; 38 (4) 340-347
    CrossrefPubMedGoogle Scholar
  • 79 Yamagami T, Kato T, Hirota T, Yoshimatsu R, Matsumoto T, Nishimura T. Infusion of 50% glucose solution before injection of ethanolamine oleate during balloon-occluded retrograde transvenous obliteration. Australas Radiol 2007; 51 (4) 334-338
    CrossrefPubMedGoogle Scholar