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Retrograde Balloon Occlusion Variceal Ablation
When compared with esophageal variceal bleeding, bleeding from gastric varices is usually more severe and difficult to control. Gastric varices are classified into two types: gastroesophageal varices and isolated varices. Gastroesophageal varices located at the cardia are considered part of esophageal varices. Gastroesophageal varices always drain into esophageal varices, and they are usually treated endoscopically ( Fig. 79.1 ). In contrast, isolated varices are usually located at the fundus or at the cardia and fundus and develop independently as part of a large portosystemic shunt that runs through the stomach wall and drains into the left renal vein or inferior vena cava (IVC) ( Fig. 79.2 ). Because of their large size and high flow, endoscopic treatment of isolated gastric varices is difficult.
Gastroesophageal varices. Coronal multiplanar reconstructed computed tomography image shows cardiac gastric varices ( GV ) draining through esophageal varices ( white arrows ) into azygos vein ( black arrows ).
Isolated gastric varices. Coronal multiplanar reconstructed computed tomography image shows gastric varices ( GV ) draining through left inferior phrenic vein ( IPV ) (gastrorenal shunt [ black arrows ]) into left renal vein ( LRV ). Note that varices also drain through subdiaphragmatic branch of left IPV into pericardiophrenic vein ( white arrows ).
Because of recent developments in interventional techniques, most isolated gastric varices can be treated safely with a balloon-occluded retrograde transvenous obliteration (BRTO) technique. In BRTO, sclerosant is injected via a balloon catheter positioned at the outlet of the vein draining the gastric varices (gastrorenal or gastrocaval shunt), and the sclerosant fills and stagnates in the varices under balloon occlusion of the shunt ( Fig. 79.3 ). When the sclerosant sufficiently stagnates in the varices, complete thrombosis of the varices can be ensured. Reported success rates of the BRTO technique have ranged from 90% to 100%. Recurrent gastric varices or rebleeding from gastric varices after BRTO occurs rarely.
Schematic drawing of standard balloon-occluded retrograde transvenous obliteration technique. Balloon catheter is introduced into outlet of gastrorenal shunt from a femoral venous approach, then sclerosant is slowly injected via balloon catheter, with balloon occlusion of shunt. Sclerosant ( purple ) fills varices.
Indications
Isolated gastric varices at high risk for rupture or those that have already ruptured are an indication for BRTO. High-risk varices include large varices, those with red spots, and rapidly growing varices. Some authors have performed BRTO for the treatment of portosystemic encephalopathy and ectopic varices such as duodenal varices. However, the long-term efficacy of BRTO for portosystemic encephalopathy has not been confirmed.
Contraindications
Portal venous pressure will be elevated after BRTO because a large portosystemic shunt is often obliterated concurrently with obliteration of the gastric varices. Therefore, portal venous occlusion or refractory ascites is generally thought to be a contraindication to BRTO. Although a selective infusion technique with a microcatheter may selectively obliterate gastric varices while preserving the portosystemic shunt, it cannot be predicted before treatment whether the shunt will be occluded. Aggravation of esophageal varices is also frequently observed after BRTO ; therefore, performance of BRTO for high-risk esophageal varices would increase the risk for bleeding from esophageal varices. In the treatment of patients with both unruptured gastric varices and high-risk esophageal varices, the esophageal varices should be treated by endoscopic techniques before BRTO.
Ethanolamine oleate, commonly used as a sclerosing agent, may induce acute renal failure because of its hemolytic effect. Renal insufficiency (serum creatinine >1.5 mg/dL) is also a contraindication or should be carefully treated.
Equipment
Balloon Catheter
A 6F to 7F Simmons-shaped balloon catheter has generally been used for occlusion of gastrorenal shunts ( Fig. 79.4 ). The balloon catheter should have a wide lumen through which a microcatheter can be inserted and should also have a large-diameter balloon (>15 mm) to occlude a large shunt completely. A 5F or 6F C-shaped catheter with a balloon has been used for occlusion of gastrocaval shunts. For the technique of selective BRTO, a 9F/5F coaxial balloon catheter that can easily be advanced proximally to the varices ( Fig. 79.5 ) is used. A microcatheter can be inserted through the 5F coaxial balloon catheter. The 9F guiding balloon is positioned at the outlet of the gastrorenal shunt, and the 5F balloon catheter is introduced coaxially into the proximal portion of the shunt over a microcatheter advanced into the varices. The sclerosing agent is then infused via the microcatheter under balloon occlusion of the shunt at the outlet and proximal portion. Microballoon catheters are recently available and are useful for selective BRTO in cases with a small and tortuous access route ( Fig. 79.6 ). These catheters come in 3.3F to 3.5F sizes with a 6- to 10-mm balloon (see Fig. 79.5 ), and they can be introduced through a 6F guiding catheter or 4F sheath over a microguidewire of 0.014 inch.
Sclerosing Agent
For BRTO, 5% ethanolamine oleate iopamidol (EOI), which consists of a mixture of 10% ethanolamine oleate (Oldamin) and the same dose of a contrast agent (iopamidol 300), is commonly used. Because some types of contrast material cannot be mixed with ethanolamine oleate, we used iopamidol 300. Ethanolamine oleate induces hemolysis in blood vessels, and free hemoglobin is released, which may result in renal tubular disturbances and acute renal failure. To prevent renal insufficiency, intravenous administration of 4000 units of haptoglobin, which combines with free hemoglobin, is performed during the procedure. Polidocanol in the form of foam has been recently used as a sclerosing agent alternative to ethanolamine olerate. Foam sclerotherapy using polidocanol may reduce the drug amount and maximize the effect by increasing the contact surface area with the venous wall. However, one should be aware of the potential risks of air embolism. Some authors used 50% glucose solution, which is infused before injection of EOI to occluded collateral veins or to replace the blood. This technique can reduce the amount of EOI.
Sodium tetradecyl sulfate (STS) is the most commonly used sclerosant within the United States. It is used at the 3% concentration and is often mixed with Ethiodol (for opacity) and air to create a foam solution. A 3:2:1 ratio (air/STS/Ethiodol) has been used successfully by the University of Virginia group. Other ratios have also been used successfully. The added Ethiodol reduces the sclerosing effect to some degree, so there is a balance between opacity and effectiveness.
Technique
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