The Conventional Balloon-Occluded Retrograde Transvenous Obliteration Procedure

Chapter 29: The Conventional Balloon-Occluded Retrograde Transvenous Obliteration Procedure


Minhaj S. Khaja and Wael E.A. Saad


Introduction


Transvenous obliteration of gastric varices can be performed from the systemic-venous side (draining veins/shunts) or from the portal-venous side (portal afferent feeders). When balloon-occluded transvenous obliteration is performed from the systemic veins, it is referred to as balloon-occluded retrograde transvenous obliteration (BRTO) (images Fig. 29.1; images Fig. 29.2). However, when balloon-occluded transvenous obliteration is performed from the portal vein and its afferent feeders, it is referred to as balloon-occluded antegrade transvenous obliteration (BATO) (images Fig. 29.3).1 BRTO is the conventional obliterative procedure because it is the least invasive choice of access or approach via a transfemoral, transrenal route25 (images Fig. 29.1; images Fig. 29.2). However, BATO is considered an alternative or adjunctive approach.1,6 The objective of BRTO and BATO is complete obliteration of the gastric varices while preserving anatomical hepatopetal flow of the splenoportal circulation.


This chapter discusses the indications, contraindications, and technical considerations of the conventional BRTO procedure. The indications of concomitant portal venous modulators such as splenic embolization or the creation of a transjugular intrahepatic portosystemic shunt (TIPS) are briefly mentioned.


Indications and Contraindications


The two clinical indications for BRTO are gastric variceal bleeding (impending, prior or current or active) and, to a lesser extent, refractory debilitating hepatic encephalopathy.7


The contraindications to BRTO are only relative contraindications at best. The contraindications include (i) severe uncorrected coagulopathy (which in this clinical setting is likely caused by liver failure), (ii) splenic vein thrombosis (segmental portal hypertension), (iii) portal vein thrombosis, and (iv) uncontrolled esophageal variceal bleeding. In patients with severe, uncorrected coagulopathy, commonly associated with liver failure, BRTO is probably being performed as an emergent, heroic measure to stop life-threatening gastric variceal bleeding. This is particularly true when the alternative (TIPS) has a high mortality rate in the setting of severe hepatic failure. The most serious contraindication, although not an absolute contraindication, is chronic portal vein thrombosis in which the gastrorenal shunt (GRS) is the only splenomesenteric (splanchnic) outflow.


Uncontrolled esophageal variceal bleeding can be considered a contraindication to BRTO when performed solely. To clarify, a combined TIPS with BRTO or TIPS with trans-TIPS BATO can be performed as necessary. Hypothetically, if the gastric varices are primarily supplied by the left gastric vein (which usually supplies uncontrolled esophageal varices), they usually respond to a TIPS equally as effectively as esophageal varices.8


Performing BRTO in the presence of portal vein thrombosis may have potentially grave consequences and is a serious dilemma for the team managing the patient. Because the entire splenic and mesenteric outflow may be through the GRS, closure of the shunt could cause splenic engorgement and more thrombosis and, potentially, venous mesenteric ischemia. In this scenario, BRTO, if performed at all, is performed as part of a greater portal procedure (beyond the scope of this chapter). Similar to portal vein thrombosis, performing BRTO in a patient with isolated splenic vein thrombosis is a dilemma. In the opinion of the current authors, the primary endovascular management, especially in the presence of splenomegaly, is partial splenic (arterial) embolization with or without BRTO.9





Table 29.1 Procedural Steps of the Conventional Balloon-Occluded Retrograde Transvenous Obliteration Procedure










































 


Broad Procedural Steps


Specific Procedural Steps


1.


Access and approach (see images Fig. 29.5)


• Venous access (femoral vs. jugular)


• Approach from infrarenal IVC or suprarenal IVC


2.


Selective catheterization (see images Figs. 29.6, 29.7, 29.8, 29.9, 29.10, 29.11, 29.12, 29.13)


• Catheterization of the left renal vein


• Catheterization of the common stump of the adrenal vein and GRS


• Selective catheterization of the GRS proper


3.


“Trapping” of the gastric variceal system (see images Figs. 29.14, 29.15, 29.16, 29.17, 29.18, 29.19, 29.20, 29.21)


• Balloon occlusion of the GRS (with balloon manipulation)


• Collateral vein embolization or sclerosis


• BATO debranching


4.


Balloon-occluded retrograde venography


5.


Sclerosant administration (see images Figs. 29.22, 29.23)


• Preferably microcatheter catheterization of the gastric variceal system


• Preferably even distribution of the sclerosant mixture


6.


Additional intraprocedural imaging (if any) (see images Fig. 29.19c-e)


• Cone-beam dynamic computed tomography


• Hemodynamic analysis and imaging


7.


Indwelling sclerosant with indwelling temporary balloon or balloon-occlusion catheter


8.


Deflation of balloon (deflation of balloon-occlusion catheter)


BATO: balloon-occluded antegrade transvenous obliteration; GRS: gastrorenal shunt; IVC; inferior vena cava. Reproduced with permission from Saad WE, Kitanosono T, Koizumi J, Hirota S. The conventional balloon-occluded retrograde transvenous obliteration procedure: indications, contraindications and technical applications. Tech Vasc Intervent Radiol 2013;16:101–151.


Technique of the Balloon-Occluded Retrograde Transvenous Obliteration Procedure


The hemodynamic endpoint of BRTO is the complete obliteration of the gastric varices while preserving the anatomical hepatopetal flow through the splenoportal veins. The concept of BRTO (images Fig. 29.1; images Fig. 29.2) is to access and occlude the GRS with subsequent reflux of sclerosant throughout the gastric variceal system without spillage into the portal circulation.24 The basic steps of the BRTO procedure are listed and summarized in images Table 29.1. The following is a detailed description of the procedural steps of BRTO of gastric varices. For the inventory used, particularly balloon-occlusion catheters and sclerosants, see Saad et al.10


The operator should note that in the setting of active gastric variceal bleeding, transoral gastric tamponade insufflation balloons (e.g., the Blakemore tube) should be used. However, if the gastric Blakemore tube is placed and inflated, it is of utmost importance that the gastric balloon be deflated (intraprocedurally) during the catheterization stage of the BRTO procedure; if inflated, the balloon compresses and distorts the varices and creates additional difficult anatomy for the BRTO procedure (images Fig. 29.4). Additionally, the compression of the gastric varices by the Blakemore balloon will not allow for adequate filling of the varices by the sclerosant, even with appropriate balloon occlusion of the gastrorenal shunt, and complete obliteration or sclerosis of the gastric varices will be virtually impossible. As a result of incomplete obliteration, if bleeding continues after the BRTO, then a balloon-occluded antegrade transvenous obliteration, TIPS, or both is required because the draining GRS at that point will be sclerosed or thrombosed.




images

Fig. 29.4 (c,d) Digital subtraction venograms, one from the gastrorenal shunt (c, GRS) and a splenoportogram (d). In both venograms the portal feeders in the splenoportogram (d), which is the posterior gastric vein (PGV) or the gastric varices (GVs) drainer, which is the GRS, are truncated because of the significant compressive nature of the fundic balloon (asterisk). The gastric varices themselves (not visualized) are completely compressed (which is the purpose of the balloon). It is paramount that the gastric balloon be deflated (intraprocedurally) during the early part (catheterization stage) of the BRTO procedure. An inflated gastric balloon compresses the gastric varices and distorts, or even compresses, the GRS anatomy, making the BRTO procedure difficult or impossible. In addition, even in the advent of balloon occluding the GRS, inadequate filling of the GVs by the sclerosant will occur because the GVs are compressed. As a result, complete obliteration or sclerosis of the GVs is virtually impossible in the presence of an inflated balloon. IVC: inferior vena cava; PV: main portal vein; SpV: splenic vein. (e) Selective venogram of the PGV leading to the GVs, which are in the gastric fundus (asterisk). The fundic balloon has been deflated to allow visualization of the GVs. The PGV is selected from a balloon-occluded antegrade transvenous obliteration (BATO) approach via a newly established transjugular intrahepatic portosystemic shunt (trans-TIPS BATO). In addition, note the BRTO balloon (open arrow). (Reproduced with permission from Saad WE, Kitanosono T, Koizumi J, Hirota S. The conventional balloon-occluded retrograde transvenous obliteration procedure: indications, contraindications and technical applications. Tech Vasc Intervent Radiol 2013;16:101–151.)


Access and Approach


For conventional BRTO (via the GRS), the approach is invariably transrenal to the GRS.25 However, the access and approach to the left renal vein can be transfemoral or transjugular24,6,1116 (images Fig. 29.1; images Fig. 29.2). The transjugular approach is advantageous in that it is less likely to introduce infection compared with the transfemoral approach and is likely better tolerated by the patient. Bacteremia suspected from the indwelling balloon has been described in 2.4% of cases.11 However, the transjugular approach requires longer reinforced sheaths to reach the GRS (at least 50- to 55-cm length), which may not be easily available to all operators. Conversely, the transfemoral approach requires shorter reinforced sheaths (40- to 45-cm length) and frees the right internal jugular vein for additional access, particularly when adjunctive transcaval phrenic vein embolization is required or for additional TIPS creation. The primary advantage of the transfemoral approach is the “pushability” of the coaxial wire and catheter system. Selection of the left renal vein and GRS from a jugular approach usually requires Cobra-shaped selective catheters and balloon-occlusion catheters. Alternatively, a Simmons-shaped catheter is usually required to select the GRS from a femoral approach, although Cobra-shaped catheters may also be used.


The distance between the common stump (of the left adrenal vein and GRS) and the inferior vena cava (IVC) can vary. Additionally, the origin of the common stump may vary in angulation as it arises from the superior aspect of the left renal vein (images Fig. 29.5; images Fig. 29.6). The GRS is easier to select from a femoral approach when it is situated closer to the IVC and has a steeper (more perpendicular) angle with relation to the renal vein. Conversely, selection of the GRS is easier from the jugular approach when it originates farther from the IVC and has a shallower (more parallel) angle with the left renal vein (images Fig. 29.6). However, this anatomical and technical divide may be moot when using the transfemoral pullback straight-sheath selection approach described later.



Catheter Selection of the Gastrorenal Shunt


The selection of the GRS is actually a three-step process, and any one of the steps can pose a significant technical challenge to the catheter selection process. The three-in-one selection includes (i) from the IVC to the left renal vein, (ii) from the left renal vein to the common stump of the left adrenal vein and the GRS, and (iii) from the common stump to the GRS proper (images Fig. 29.7). The complexity of the selection is because the GRS is commonly a gastroadrenorenal shunt (images Fig. 29.8) where the gastric variceal drainage (the shunt) merges with the left adrenal vein to form a common stump (asterisks in images Fig. 29.5 and images Fig. 29.8).



images

Fig. 29.6 Choice of approach (transjugular or transfemoral) based on the varying anatomy of the distal gastrorenal shunt (GRS) and its venous outflow. The GRS commonly does not empty directly into the left renal vein (LRV) but actually empties in the LRV via a common stump with the left adrenal vein. For labeling of anatomical structure, see images Fig. 29.5. (a) The takeoff of the common stump of the GRS is close to the junction of the LRV with the inferior vena cava (IVC) and makes a shallower angle (more parallel to the LRV) with the LRV. Catheterization in this setting is more favorable via a transfemoral approach. The primary factor for a transfemoral approach here is the short distance between the GRS (common stump) and the IVC. (b) The takeoff of the common stump of the GRS is more or less midway between the LRV–IVC junction and the left renal hilum. In addition, the GRS makes a shallower angle (more parallel to the LRV) with the LRV. This anatomical setting is between images Fig. 29.6a and Fig. 29.6c, and catheterization in this setting can be via a transfemoral or transjugular approach (depending on operator preference and availability of inventory). (c) The takeoff of the common stump of the GRS is a distance from the junction of the LRV with the IVC and makes a steep angle (more perpendicular to the LRV) with the LRV. Catheterization in this setting is more favorable via a transjugular approach. (Reproduced with permission from Saad WE, Kitanosono T, Koizumi J, Hirota S. The conventional balloon-occluded retrograde transvenous obliteration procedure: indications, contraindications and technical applications. Tech Vasc Intervent Radiol 2013;16:101–151.)





images

Fig. 29.8 (g) Venogram in the same patient as (d-f) detailing the venographic anatomy of the common stump and distal GRS (h is a magnified inset). The catheter is in the distal GRS proper and has reached there by being advanced through a web narrowing (between solid arrows, h). Contrast is seen refluxing into the IPV and emptying into the common stump (asterisk) of the GRS and the adrenal vein(s). The common stump empties into the LRV and subsequently the IVC. Web narrowings are difficult to traverse with catheters and wires. However, when traversed, they make very effective “choke points” that do not necessarily require balloon sizes greater than 10 mm to occlude (f). (i) Venogram in a completely different patient from parts b and c of the common stump and distal GRS and the adrenal vein with a magnified inset (j) via a Simmons II catheter. Contrast is seen in the common outflow stump (asterisk) of the adrenal vein and the GRS proper. Occasionally, the GRS is not seen, but its effect (wash-in) is seen in the venogram of the common stump. Operators must be cognizant of this and identify it. Identifying the wash-in (i, solid black arrow) of the GRS is important because it tells the operator where to direct the selection catheter and wire to selectively catheterize the GRS proper. The GRS proper is not seen but is drawn out in (j). The GRS proper merges with the common stump at different angles and approaches (see k-n for detailed examples). (k-n) The GRS proper merges with the common stump at different angles and approaches. These are different common stump venograms with accompanying simplified schematic demonstrating the different angles and approaches for the merging of the GRS proper with the common venous outflow stump of the GRS proper and the left adrenal vein. (k) The most common relationship in which the GRS proper anastomoses at the 10 to 11 o’clock position with the common stump (asterisk). The solid black arrow denotes the inflow of the GRS proper (i,j). (l) Demonstrates another very common relationship where the GRS proper (GRS) anastomosis at the 11 to 12 o’clock position with the common stump (asterisk). The GRS is right on top of the common stump but because the adrenal vein comes from the lateral aspect of the stump the GRS is inclined medially.





For the purpose of the anatomical description below, the portosystemic shunt draining the gastric varices into the “common gastroadrenal stump/common stump” is referred to as the GRS proper. Occasionally, there is little discernible difference between the common stump and the GRS proper. However, not infrequently, a web is found across the junction of the GRS proper with the adrenal vein stump (images Fig. 29.8), which is difficult to catheterize, especially when there is very little wire and catheter “purchase” into the common stump. For further details of this anatomy, please see Chapter 28.


When no discernible difference between the adrenal vein stump and the GRS proper (and no web narrowing) is found, it is easy to make this three-stage selection using a Cobra- or Simmons-shaped balloon-occlusion catheter from a transjugular or transfemoral approach, respectively (images Fig. 29.9). However, because these balloon-occlusion catheters are not currently available in the United States, American interventionalists have to selectively catheterize the GRS proper with a selective catheter and then perform an over-wire exchange for one of the commercially available straight balloon-occlusion catheters. This exchange requires adequate stiff wire “purchase” in an area of anatomy that may not allow a lot of wire purchase. Certain techniques described later can be used to selectively catheterize the GRS proper and advance a reinforced sheath and balloon-occlusion catheter in the setting of difficult anatomy.


As discussed, Cobra-shaped catheters are typically used to select the GRS from the transjugular approach (images Fig. 29.10). However, the Cobra catheter may also be helpful in selecting the GRS proper from the common stump in the presence of a web narrowing at the GRS proper to common stump junction from a femoral approach. The Cobra shape helps catheterize the left renal vein. Next, the Cobra catheter is then flipped upward so that it “scrapes” the superior aspect of the left renal vein as it is pulled back until it selects the upward-pointing common stump. A JB-2 catheter may also be used without the need to flip the catheter upward. If the left renal vein has been successfully selected and there is room to form a reverse-shaped catheter, it can be used to select the common stump. A reverse-shaped catheter is especially helpful in selection if the common stump or the GRS proper points medially in the 9 to 11 o’clock position (images Fig. 29.8d; images Fig. 29.8e). Reverse-shaped catheters that can be formed in the left renal vein include a Simmons I or an SOS-shaped catheter. A reverse-shaped Simmons II catheter is ideal for selecting the GRS in a picturesque manner (images Fig. 29.11).


Oct 29, 2018 | Posted by in CARDIOLOGY | Comments Off on The Conventional Balloon-Occluded Retrograde Transvenous Obliteration Procedure
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