Methods
In 2022, the SGEI board convened the SGEI EUS-BD Consensus Working Group comprising
experts in therapeutic endosonography who are involved in training. Topic-specific
tasks were assigned to the working group members, and clinical key questions were
generated for discussion in the consortium. Searches were performed on Medline and
the Cochrane Library till March 2022. The level of evidence for each statement was
graded as per the Grading of Recommendations, Assessment, Development, and Evaluations
(GRADE) system.[9] Recommendations were drafted, and the strength was ascertained based on the level
of evidence ([Supplementary Table S1], available in the online version only). The members of the expert group met in person
to discuss and vote on the recommendations. Voting was done by electronic keypads.
Statements with more than 80% total or partial agreement were accepted, while those
with major disagreements were discarded or modified after discussion. A second and
final round of voting was done to record all statements finally agreed upon. The recommendations
developed by this expert group were divided into two parts: (1) general guidance on
indications and outcomes, and (2) the technical aspects of “how to do” EUS-BD. This
manuscript represents the outcome of the Delphi process resulting in the development
of technical guidelines on how to perform EUS-BD.
General Technical Aspects of EUS-BD
EUS-BD encompasses a multitude of approaches and techniques, including transluminal,
antegrade, and rendezvous techniques. The transluminal approach involves the creation
of a permanent new bilioenteric fistula between the biliary system and the stomach,
i.e., hepaticogastrostomy (EUS-HGS), or the duodenum, i.e., choledochoduodenostomy
(EUS-CDS) and hepaticoduodenostomy (EUS-HDS). The antegrade technique (EUS-AG) entails
the placement of transpapillary stents after gaining transgastric access to the proximal
biliary system in the liver. In the rendezvous technique (EUS-RV), the biliary system
is accessed using EUS guidance via transgastric or transduodenal routes. First, a
guidewire is negotiated across the papilla and then used to perform an ERCP conventionally.
This technique is also known as the EUS-guided biliary access procedure. Depending
on the type of access approach, EUS-BD can be performed via the intrahepatic route
(EUS-HGS, EUS-AG, EUS-RV, EUS-HDS) or the extrahepatic route (EUS-CDS, EUS-RV).
Nevertheless, all the various techniques are performed using common basic tools such
as scope, needle, wire, and accessories used for tract dilation.
SGEI recommends that a therapeutic linear echoendoscope is suitable for EUS-BD procedures.
A forward-viewing echoendoscope may be used for EUS-CDS
Agreement: 92.7%. Level of evidence: III. Grade of recommendation: C.
Echoendoscopes are broadly of two major types: radial and curvilinear. Radial echoendoscopes
are used for diagnostic purposes, while oblique-viewing curvilinear echoendoscopes
are used for biopsies and therapeutic procedures. Irrespective of the manufacturer,
a therapeutic curvilinear echoendoscope with a working channel of 3.7-mm diameter
is routinely preferred for all therapeutic EUS-guided procedures, including EUS-BD.[10] A 3.7-mm working channel can allow passage of 10-Fr accessories, compared with the
thinner 2.8-mm working channel scopes that can accommodate only 7-Fr accessories,
and is hence preferred.
A relatively newer echoendoscope is the forward-viewing curvilinear array echoendoscope
(FV-CLA). Although the scanning view is limited to 90 degrees, this scope has the
advantages of offering a forward endoscopic view, lack of the “push-back” phenomenon
on the scope by the advancing needle, and better transmission of the force.[11] Of late, FV-CLA has been used for various therapeutic procedures, including EUS-BD.[12] FV-CLA has been used to perform EUS-CDS[13] and EUS-HGS successfully.[14]
[15] During EUS-CDS, the endoscopic images become indispensable for safely placing the
proximal part of the stent, as the proximal duodenum has limited space for any scope
manipulation. In this scenario, an FV-CLA has an expectedly better safety profile
due to superior endoscopic view and has reported high technical success.[13] Thus, an FV-CLA can be used as an alternative for performing EUS-CDS wherever available.
SGEI recommends that a 19-G needle is the preferred choice for biliary puncture. However,
a 22-G needle can be used in the setting of a nondilated biliary system.
Agreement: 100%. Level of evidence: III. Grade of recommendation: C.
Most studies report using a 19-G fine needle aspiration (FNA) needle for EUS-BD. A
needle of 19 G allows both 0.025- and 0.035-inch guidewire, which are easier to manipulate
than a 0.018-inch guidewire. However, it might be difficult to maneuver standard 19-G
steel needles in difficult angulated positions such as the duodenum. Nitinol needles
are more flexible and less prone to bending. Moreover, the coil sheath possesses higher
lumen retention than the plastic sheath. As a result, these “flexible” nitinol needles
may be preferred in difficult scope positions during EUS-BD.[16]
Although 19 G is the preferred needle size, it can be technically difficult to use
in a nondilated ductal system. A 22-G needle with an 0.018-inch guidewire can be used
in such situations. Recent studies have shown that this strategy is equally effective
for EUS-BD.[17]
[18]
[19]
[20] In fact, a recent prospective comparative study using a 19-G needle for a duct diameter
of >1.5 mm and a 22-G needle for a duct diameter of <1.5 mm showed similar technical
success (100 vs 89%) of the two needles.[21] Thus, for a nondilated system, a 22-G needle with 0.018-inch guidewire is a viable
alternative. Tract dilation, however, is technically difficult with 0.018-inch guidewire,
and hence, novel thin mechanical dilators have been designed for the same (not available
in India).[19]
SGEI recommends that a 0.025- to 0.035-inch guidewire with a hydrophilic tip is preferred.
Short wires may be used if expertise is available.
Agreement: 92.8%. Level of evidence: III. Grade of recommendation: C.
High-performance guidewires with good torque ability, pushability, and tip flexibility
are needed for navigation across strictures. Both 0.025- and 0.035-inch guidewires
are equally effective and commonly used for EUS-BD. Thinner wires can get damaged
easily and are unsuitable for tract dilation or stent placement.
Although standard long wires (400 cm) are used, efficacy data on using shorter (280 cm)
hydrophilic guidewires exist.[22]
[23] The completely hydrophilic wire can have better efficacy in negotiating strictures
and papilla. However, saline must be pushed through the needle hub during needle exchange
to “float” the wire and maintain its position.[23] Thus, centers or endoscopists with adequate expertise may use these short wires
(280 cm).
SGEI recommends that for tract dilation, a coaxial cautery device is preferred. Mechanical
dilators may also be used. Lumen-apposing metal stents (LAMS) may be placed without
tract dilation.
Agreement 100%. Level of evidence: III. Grade of recommendation: C.
After guidewire negotiation, tract dilation is a crucial step in EUS-BD. The tract
dilatation can be done by electrocautery, mechanical, or balloon dilators. Electrocautery
dilators include coaxial diathermy catheters: (1) 6-Fr cystotome with diathermic tip
(ENDO-Flex GmbH, Voerde, Germany) and (2) Fine 025 (Medico's HIRATA Inc, Osaka, Japan)
with 3-Fr metal tip. Mechanical dilators include (1) bougie dilator, Soehendra (Cook
Medical, Bloomington, IN, United States) or (2) ultratapered (2.5 Fr) mechanical dilator
(ES dilator, Zeon Medical Co., Tokyo, Japan). Balloon dilators include (1) Hurricane
Rx Balloon – 4 mm (Boston Scientific, Natick, MA, United States) or (2) REN, 0.025
sharp tip – 4 mm (Kaneka Medix Corporation, Japan). The dilation devices available
in India are cystotome, Soehendra bougie, and balloon dilators.
While coaxial dilation devices are preferred, needle-knife sphincterotome should not
be used as it is associated with higher adverse events.[24]
[25]
Of the coaxial dilators, electrocautery and mechanical can both be used for EUS-BD.
However, there are certain caveats to using mechanical dilators, such as the following:
(1) inadequate penetration ability across a tough tract with fibrotic or hard tissues
because of nonsharp tip; (2) long length of the tract to be dilated, more for procedures
such as EUS-HGS and EUS-AG; and (3) inadequate force transmission through a nonaligned
oblique-viewing curvilinear scope, which might be in an unstable position in a large
stomach. Thus, dedicated thin mechanical dilators with sharp tips would be required
to overcome these concerns,[26] which are currently unavailable in India. Cautery dilators, on the other hand, have
been shown to shorten procedure time for draining pancreatic fluid collection[27] and EUS-BD.[26] Hence, they might be preferred over mechanical dilators as of now. In addition,
cautery devices have been reported to have early and late “burn effects,” but these
can be mostly managed conservatively. Similarly, cautery-mounted LAMS are single-step
devices designed to dilate the tract and place the stent with the same catheter. Thus,
they usually do not require additional tract dilation.
EUS-Guided Choledochoduodenostomy: Technical Aspects
EUS-CDS is the technique of creating a fistula between the duodenum and the bile duct
and bridging it with a stent. With a technical success rate of 90 to 95% and adverse
event rate of 12 to 20%, EUS-CDS is considered technically easier compared with other
EUS-BD procedures.[28] The basic steps entail puncturing the bile duct from the duodenum, negotiating the
guidewire up the hilum, dilating the tract, and placing the stent. However, the lack
of intervening hepatic parenchyma and angled scope poses some challenges during EUS-CDS.
Therefore, the key aspects of this procedure were discussed in the consensus meeting,
and four statements were proposed.
SGEI recommends that a long or intermediate scope position in the duodenal bulb is
preferred. The needle direction should be toward the liver hilum.
Agreement: 100%. Level of evidence: IV. Grade of recommendation: D.
In EUS-CDS, the echoendoscope is positioned in the duodenum, and the common bile duct
(CBD) is interrogated in a long position to assess the severity of dilation and the
location of the obstruction. The proximity of the CBD to the duodenal bulb and the
retroperitoneal position of the CBD make CDS an attractive therapeutic option. Thus,
the scope needs to be placed in the duodenal bulb. The procedure is performed with
the scope in the long or intermediate position, enabling scope stability. Moreover,
as the guidewire needs to be directed toward the hilum, the scope tip should be positioned
toward the hilum. This echoendoscope shape should be confirmed on fluoroscopy.[29] The patient position during CDS can be either supine, prone, or left lateral, although
the ductal anatomy on cholangiogram may be better delineated under fluoroscopy in
the supine or prone position.
Akin to the scope position, the needle, too, should be directed toward the hilum.
The wire can be easily negotiated to the hilum when the FNA needle comes out nearly
parallel to the CBD axis on EUS imaging. Specialized needles, such as the steerable
access needle, can help manipulate the wire in the desired direction after the puncture.
In this needle, the access catheter is blunt-tipped and rotatable and can assume a
preset curvature (90 or 135 degrees) once the sharp stylet is removed. Ryou et al[30] evaluated this needle in 22 EUS-BD cases, including 7 EUS-CDS, and found it to be
a useful device for selective positioning and advancement of wire.
SGEI recommends that needle puncture be done preferably from the duodenal bulb, avoiding
double duodenal folds.
Agreement: 100%. Level of evidence: IV. Grade of recommendation: D.
One of the technical steps of EUS-CDS is puncturing the CBD from the duodenum. Sometimes,
a double duodenal mucosal fold can interrupt the needle path leading to perforation
or bleeding.[31] This double mucosal puncture can be avoided using the water-filling technique,[32] wherein intraluminal water instillation flattens out the duodenal folds. Additionally,
Matsumoto et al[33] have shown that one of the risk factors of double mucosal puncture was using an
oblique-viewing echoendoscope. This can be avoided by using a forward-viewing echoendoscope,
which can be opposed to the puncture site and, thus, prevent double puncture. However,
since a forward-viewing echoendoscope is not frequently used or may not be available
in all centers, using the water-filling technique and careful assessment of the duodenal
wall anatomy on EUS before puncture is essential to avoid this complication.
SGEI recommends that a fully covered self-expanding metal stent (FC-SEMS) or an LAMS
is the stent of choice in EUS-CDS.
Agreement: 100%. Level of evidence: III. Grade of recommendation: C.
The choice of the stent for EUS-CDS is a cardinal step to prevent adverse events.
While plastic and metal stents can be placed for EUS-CDS, plastic stents are a significant
predictor of peritonitis.[33] The relatively narrower diameter of the plastic stent predisposes to bile leakage
between the stent and the created fistula. Therefore, plastic stents should not be
placed for EUS-CDS.
Generally, FC-SEMS are used for EUS-CDS. They are either braided or laser-cut.[29] One of the key risks of FC-SEMS is stent migration. While laser-cut may have a lower
migration rate, it can be complicated by kinking of the stent. Cho et al[34] have evaluated a partially covered stent or hybrid stent with proximal and distal
anchoring flaps to prevent migration. Their study on 33 EUS-CDS cases did not have
any migration. Ogura et al[35] found that a double-bared stent with low axial force has less stent dysfunction
due to kinking than FC-SEMS.
LAMS, first reported in 2011,[36] have high appositional force and adhere the gastrointestinal lumen with the target
area. Thus, the issue of stent migration can be avoided. With the advent of the electrocautery-enhanced
LAMS delivery system (ECE-LAMS), other tract dilations and accessories exchange were
avoided, reducing adverse event rates and procedure time.[37] Jacques et al[38] evaluated the utility of ECE-LAMS using the “recommended” technique of direct fistulotomy
with pure cut current and a 6- or 8-mm stent. They found a very high technical success
rate of 97.1%. While performing EUS-CDS using ECE-LAMS, the preferred diameter of
CBD is >10 mm,[37] and a protective guidewire may be considered in case the CBD ≤ 10 mm. A recent meta-analysis
showed that ECE-LAMS have a pooled technical success rate of 95.7% and an adverse
events rate of 5.6%.[39] Comparison of LAMS with SEMS showed that both were equally effective for EUS-CDS
with similar adverse event rates.[40]
Since the distal flange of the stent is in the lumen, food/residue impaction is quite
common. In a multivariate analysis, Matsumoto et al[33] demonstrated that stent opening toward the oral side posed a greater risk for stent
dysfunction than the anal side. However, more data are needed to prove this important
hypothesis. Additionally, the presence of significant gastric outlet obstruction may
pose added risk of stent dysfunction for EUS-CDS and might warrant using other modalities
of biliary drainage.
The placement of coaxial plastic stents through the LAMS/SEMS has the theoretical
advantage of preventing stent migration and avoiding recurrent biliary obstruction
due to stent blockage. El Chafic et al[41] showed that coaxial plastic stents could significantly reduce the need for biliary
interventions. However, other studies failed to show any difference.[42]
[43] A large multicenter randomized controlled trial is underway to answer this question
better.[44] A coaxial plastic stent may be placed in EUS-CDS, depending on the endoscopist's
discretion.
SGEI recommends that intrachannel stent deployment is suggested for the distal end
of the stent.
Agreement: 100%. Level of evidence: IV. Grade of recommendation: D.
After tract dilation, the stent is deployed. While the proximal part of the stent
is deployed inside the CBD under fluoroscopic guidance, releasing the stent in the
duodenal lumen can be tricky. Duodenum, unlike the stomach, has little space; thus,
maneuvering the scope for distal stent release under endoscopic visualization is difficult.
As a result, there can be accidental migration of the stent into the abdominal cavity,
or the scope may rapidly fall back into the stomach, risking the unintentional pullout
of the whole stent along with it inside the lumen. To avoid this, intrachannel deployment
of the stent seems a good strategy.[29]
[45] The distal end of the stent is deployed inside the channel of the echoendoscope,
and then gradually, the stent is pushed out of the channel while withdrawing the scope.
Maintaining the guidewire access till the last step is key to troubleshooting in cases
of stent maldeployment. The delivery catheter may be exchanged over the guidewire
after stent deployment, keeping the guidewire in place till the stent position has
been confirmed on endoscopy/fluoroscopy. In case of maldeployment of the stent, this
guidewire access can then be used to place a second stent to bridge the tract created
and complete the procedure.
EUS-Guided Hepaticogastrostomy: Technical Aspects
EUS-HGS, first described by Burmester et al,[46] involves the creation of a fistula between the stomach and the left ductal system
and bridging it with a stent. The pooled technical success rate of EUS-HGS is 96.6%,
with an adverse events rate of 17.5%.[47] The key technical aspects of EUS-HGS determining the procedure's success include
the following: (1) puncture of the appropriate segment; (2) guidewire manipulation,
the most crucial step; (3) choice of the stent; and (4) stent deployment strategy.
The working group discussed the various aspects and developed four main technical
recommendations for EUS-HGS.
SGEI recommends that segment 3 duct is the preferred access site for EUS-HGS.
Agreement: 100%. Level of evidence: III. Grade of recommendation: C.
Access to the left ductal system from the stomach can be achieved by puncturing the
B2 or B3 segment. While no head-to-head trial exists between the two approaches, the
preferred approach used by most studies is the B3 segment. Guidewire manipulation
is easier after a B2 puncture, but the puncture can sometimes be from the esophagus.
The transesophageal approach can lead to mediastinal emphysema, mediastinitis, and
pneumothorax.[48] Even if the puncture is just below the gastroesophageal junction (GEJ), the deployed
stent might be directed toward the oral side, leading to adverse events.[49] Although a recent study has evaluated the technique of B2 puncture for HGS using
a forward-viewing scope, the authors have used a clip to landmark the GEJ on fluoroscopy
to prevent esophageal puncture.[15] To avoid this inadvertent esophageal puncture, it is recommended that the puncture
be made into the B3 segment. The scope tip can be angled only to around 170 degrees
when in the esophagus but to 90 degrees when in the stomach, and this shape can be
double-checked on fluoroscopy to ensure the puncture site.
Guidewire manipulation toward the hilum is the most critical step in HGS, and the
angle of the puncture becomes an important determinant. Ogura et al[50] have shown that an angle of >135 degrees (obtuse angle) between the FNA needle and
the echoendoscope on fluoroscopy was an independent predictor of successful guidewire
negotiation. Various techniques have been described to facilitate guidewire manipulation,
such as the “liver impaction” technique to prevent wire shearing,[51] the “moving endoscope” technique to change the needle-scope angle,[52] the “jumping technique” of guidewire manipulation,[53] and the physician-controlled guidewire manipulation.[54] A few other factors, such as the minimum ductal diameter and optimum hepatic parenchyma
length, have been systematically evaluated during the ductal puncture. A study of
174 HGS cases noted that a ductal diameter of ≤5 mm was associated with low technical
success.[55] While Oh et al[55] suggested that hepatic parenchyma length of 1 to 3 cm was optimum, Yamamoto et al[56] recently showed that hepatic portion length of ≤2.5 cm was an independent risk factor
for biliary peritonitis. Thus, more data are needed to opine the optimum hepatic parenchyma
length. One study by Ishiwatari et al[57] has shown that aspiration of the bile (>10 mL) during HGS reduces the risk of adverse
events, primarily postprocedure cholangitis and bile leak.
SGEI recommends that a tubular, partially covered metal stent is used for HGS.
Agreement: 100%. Level of evidence: III. Grade of recommendation: C.
The choice of the stent is crucial for the procedure's success and for avoiding complications.
FC-SEMS and partially-covered self-expanding metallic stents (PC-SEMS) have been used.
FC-SEMS can lead to segmental cholangitis by blocking the peripheral branches. PC-SEMS
essentially has two features: (1) uncovered part to prevent obstructive cholangitis
and (2) covered portion placed across the liver parenchyma and the tract into the
stomach. The uncovered part of the stent additionally acts as an anchor inside the
biliary system.[29] Hence, the use of a tubular PC-SEMS is advocated. The risk, however, is the accidental
deployment of the uncovered portion outside the liver parenchyma, leading to a bile
leak.
The various kinds of stents evaluated for EUS-HGS have been briefed in [Table 1]. Dedicated stents and accessories for EUS-HGS are limited; thus, newer devices are
being evaluated to get the best answer. Park et al[58] evaluated, in a randomized controlled trial, a one-step EUS-BD device with a 3-Fr
catheter and a 4-Fr tapered metal tip for placement of stent without the need for
additional dilation. This stent system showed significantly lower procedure time and
the need for further fistula dilation. The stent also had four flaps at the distal
end to prevent migration. Cho et al evaluated another hybrid stent (Standard Sci Tech
Inc, Seoul, South Korea) with antimigratory anchoring flaps at the two ends of the
covered portion.[34] They found that none of the stents had migration. However, these stents, as mentioned
earlier, are not currently available in India.
Table 1
Characteristics of specific stents used for EUS-guided biliary drainage
|
Stent
|
Manufacturer
|
Diameter
|
Length
|
Special features
|
|
EUS-HGS
|
|
Giobor Stent
|
Taewoong Medical, South Korea
|
8, 10 mm
|
8, 10 cm
|
Covered:uncovered, 50:50 and 70:30
Flared end at gastric side
Delivery system: 8.5 Fr
|
|
SPAXUS-MG
|
Taewoong Medical, South Korea
|
8, 10 mm
|
6, 8, 10 cm
|
Uncovered segment with marker 15 mm
Marker for gastric segment 20 mm
Delivery system: 8.5 Fr
Proximal anchoring flange: 20 mm
|
|
Hybrid Stent[a]
|
Standard Sci Tech, South Korea
|
8, 10 mm
|
5–10 cm
|
Distal silicone covered: 3.5 cm
Antimigration flaps: 4
Proximal uncovered: 1.5–5 cm
|
|
Hanarostent BPD
|
MI Tech, Seoul, South Korea
|
10 mm
|
8, 10 cm
|
Uncovered part: 30 mm
Delivery system: 8.5 Fr
Flared gastric flap (20 mm) with lasso
|
|
DEUS delivery system[a]
|
Standard Sci Tech, South Korea
|
6 mm
|
5–10 cm
|
Covered:uncovered: 85:35
3-Fr/4-Fr tapered pentagonal metal tip
Delivery catheter: 7 Fr
Single one-step stenting device
Proximal anchoring flaps; funnel-shaped uncovered wire mesh
|
|
Spring Stopper[a]
|
Taewoong Medical, South Korea
|
|
|
1.5–2 cm uncovered part
Stopper on stomach side
|
|
BileRush Advance[a]
|
Piolax Medical, Kanagawa, Japan
|
8 mm
|
9, 10, 12 cm
|
2 cm uncovered part
Delivery system: 7 Fr with tapered tip (no need for tract dilation)
Flared end on stomach side
|
|
Laser-cut stent with anchoring hook[a]
|
Zeon Medical, Tokyo, Japan
|
8 mm
|
10 cm
|
1 cm uncovered part
Delivery system: 7.2 Fr with tapered tip
3 hooks on the stomach side
|
|
EUS-CDS
|
|
Hot-AXIOS
|
Boston Scientific, USA
|
6, 8 mm
|
8 mm
|
LAMS designed for EUS-CDS
CBD diameter should be ≥ 1.5 cm
|
|
Double bare covered stent, EGIS
|
S&G Biotech, South Korea
|
10 mm
|
6 cm
|
8-Fr delivery catheterLower axial force
|
|
Covered BileRush[a]
|
Piolax Medical, Kanagawa, Japan
|
6 mm
|
6 cm
|
7.5-Fr delivery catheter
Laser-cut nitinol wire
5 mm at the proximal end uncovered
10 m flare at both ends
|
Abbreviations: CBD, common bile duct; EUS-CDS, endoscopic ultrasound-guided choledochoduodenostomy;
EUS-HGS, endoscopic ultrasound-guided hepaticogastrostomy; LAMS, lumen-apposing metal
stents.
a These stents are not available in India.
Plastic stents are usually not advocated for use in EUS-HGS. This procedure entails
tract dilation between two mobile organs (stomach and liver) and bridging it with
a stent. Thus, currently available plastic stents are not designed to serve this purpose
and bear a high risk for bile leakage, peritonitis, stent migration, etc. Furthermore,
plastic stents have been found to be a significant predictor of adverse events after
EUS-HGS.[25] A dedicated EUS-HGS plastic stent (15-cm effective length; single pigtail; four
flanges with apertures; tapered tip) is available in Japan[59] and is technically feasible, although more data are needed.
SGEI recommends an intragastric stent length of 3 to 5 cm is recommended to prevent
proximal stent migration.
Agreement: 100%. Level of evidence: III. Grade of recommendation: C.
One of the dreaded complications of EUS-HGS is stent migration. Extraluminal migration
can lead to an open bile leakage and biliary peritonitis requiring surgery. Thus,
measures to prevent stent migration are key. While various antimigratory flaps and
flares are present in different designs of stents, the length of the stent, both intragastric
and overall, is an important parameter. Nakai et al found that a total stent length
≥ 10 cm has no migration risk.[60] While long intragastric stent length can help prevent stent migration, too long
an intraluminal segment can make reintervention difficult. Thus, an optimum intraluminal
length of the stent is required. An intragastric stent length of ≥3 cm has been shown
to have lower stent migration[61] and longer stent patency.[62] Thus, a minimum length of 3 cm is desired in the stomach. Additionally, too long
a stent segment can make reintervention difficult as the distal stent end would drop
into the stomach. Hence, the consensus proposed that an intragastric length of 3 to
5 cm would be optimum for preventing migration and gaining access for reintervention.
SGEI recommends that for EUS-HGS, intrachannel stent deployment is suggested.
Agreement :100%. Level of evidence: III. Grade of recommendation: C.
Stent deployment is a final cardinal step, and inappropriate placement can lead to
stent migration and other complications. There are two techniques for the distal deployment
of EUS-HGS stents: (1) within the channel (intrachannel) deployment or (2) deployment
under endoscopic vision. The intrachannel deployment showed higher technical success
with lower adverse events.[63] Additionally, objective assessment has shown that the hepatic parenchyma–stomach
distance is shorter during intrachannel deployment compared with extrachannel deployment.[45] This translates to a lower incidence of “candy” signs and other adverse events.
Thus, it is recommended that the stent be deployed within the channel and then pushed
out using endoscopic and fluoroscopic guidance. As discussed earlier, maintaining
the guidewire access till the last step is key to troubleshooting in cases of stent
maldeployment. In case of maldeployment of the stent, this guidewire access can then
be used to place a second stent to bridge the tract created and complete the procedure.
Once the distal flange has been deployed inside the biliary system, one should maintain
controlled traction on the delivery catheter during the deployment of the rest of
the stent. This is a key step to avoid the separation of the liver and stomach, leading
to a “candy sign.”
EUS-Guided Antegrade Intervention: Technical Aspects
EUS-AG is useful for establishing physiological bile flow across an inaccessible papilla.[64] Additionally, this technique can be used for benign diseases with altered anatomy.
However, this is a technically challenging procedure with a lower success rate of
77% and adverse events rate of 5%.[65] The rate-limiting step is the guidewire negotiation across the papilla. While most
steps are similar to EUS-HGS, additional technical aspects include delineation of
the lower-end biliary stricture, position of papilla, and stent placement. The consensus
has recommended three main technical recommendations for EUS-AG.
SGEI recommends that needle puncture through segment 3 is preferred for EUS-AG as
it allows conversion to EUS-HGS in case of failure of antegrade guidewire manipulation.
Agreement: 100%. Level of evidence: IV. Grade of recommendation: D.
As discussed, the B2 segment puncture can help get a relatively straighter course
to the papilla. Additionally, the force transmission to the devices is better, enabling
tight stricture/neoplastic lesion negotiation[66] with B2 puncture. However, the inability to pass the wire across the papilla might
require converting the intended EUS-AG procedure to EUS-HGS. However, as discussed
earlier, EUS-HGS would be risky from the B2 segment. Therefore, the consensus committee
has recommended a B3 puncture so that EUS-HGS can be completed lest the wire does
not cross the papilla.
SGEI recommends that an ERCP cannula or a 6-Fr cystotome allows better control during
guidewire manipulation with the possibility of performing a cholangiogram to delineate
the stricture.
Agreement: 100%. Level of evidence: IV. Grade of recommendation: D.
While systematic data do not exist for guidewire manipulation techniques of EUS-AG,
it is imperative that guiding the wire all the way down across the papilla from the
intrahepatic puncture site is not feasible with the FNA needle. Thus, an ERCP cannula
or a 6-Fr cystotome is recommended as an effective approach for guidewire manipulation.[66] This enables better pushability and torquing for the guidewire. Additionally, the
catheter can be used for obtaining a cholangiogram, delineating the anatomy of the
stricture and marking the papilla's exact location on fluoroscopy.
SGEI recommends that uncovered SEMS may be preferred in EUS-AG for malignant biliary
obstruction.
Agreement: 100%. Level of evidence: II. Grade of recommendation: C.
In patients with distal malignant bowel obstruction (MBO) undergoing EUS-AG, the stent
placed across the papilla cannot be removed through the fistula created. Any need
for reintervention would entail fresh puncture and access to the biliary system such
as the index procedure. The choice of the stent type (covered or uncovered) depends
on multiple factors. The two main concerns of EUS-AG are bile leak from the puncture
site and pancreatitis due to the stent placed across the papilla. Surprisingly, pooled
data do not show bile leak as the major adverse effect. The commonest adverse effect
is pancreatitis.[67] Pancreatitis can be avoided by placing the stent proximal to the papilla. However,
that might not be feasible in EUS-AG for MBO as the obstruction might not be far from
the papilla. Moreover, the stent not being placed across the papilla might not decrease
the intrabiliary pressure adequately and can lead to an increased risk of bile leak
from the puncture site. Thus, a stent has to be placed across the papilla.
Looking at ERCP data of covered versus uncovered SEMS across the papilla, one can
observe no difference in the pooled incidence of pancreatitis.[68] However, the scenario is slightly different for EUS-AG as sphincterotomy is not
feasible in EUS-AG. A prospective study showed that the rate of pancreatitis in EUS-AG
with uncovered SEMS was 15%, mild in intensity.[69] Another multicenter study showed that hyperamylasemia was noted in 8.1% of cases
without clinical pancreatitis[70] with uncovered SEMS. In contrast, a recent study on EUS-AG with covered SEMS showed
that 24% of patients developed mild pancreatitis.[71] Although there is no head-to-head trial, this hints that covered SEMS might have
a slightly higher risk of postprocedure pancreatitis in EUS-AG.
While covered SEMS have low tissue ingrowth, they have higher tissue overgrowth and
higher stent migration rates than uncovered ones[68] with similar stent patency rates. Covered SEMS have a theoretical risk of acute
cholecystitis from cystic duct block, although there are insufficient data to say
that. Moreover, the delivery system of uncovered SEMS is thinner, allowing easy passage
across the fistula tract without the need for greater dilation. Thus, considering
multiple factors, the working group suggested using uncovered SEMS for MBO in EUS-AG.
However, additional stent properties may be preferred, such as those with lower foreshortening
postdeployment.
EUS-Guided Rendezvous: Technical Aspects
Of all the EUS-guided biliary access techniques, EUS-RV is an EUS-assisted technique
that facilitates subsequent ERCP in a previously failed case by passing a guidewire
across the papilla. Thus, it is theoretically one of the safest EUS-BD techniques
with a relatively lower pooled technical success rate of 86.1% and adverse events
rate of 14%.[72] The two key technical steps for EUS-RV are the site of puncture and the strategy
for cannulation attempt after scope exchange. The working group has recommended three
main technical aspects to be considered while performing EUS-RV.
SGEI recommends that performing the EUS-extrahepatic approach may be preferred over
the intrahepatic approach when both are technically feasible.
Agreement: 100%. Level of evidence: III. Grade of recommendation: C.
The biliary system can be accessed in EUS-RV by the intrahepatic approach from the
stomach or the extrahepatic approach from the duodenum. The scope position in the
transgastric intrahepatic approach is stable, with the needle pointing toward the
hilum. Still, the distance from the papilla is long and may have difficult wire manipulation.
On the other hand, the extrahepatic transduodenal approach has two scope positions:
(1) shortened echoendoscope placed in the duodenum D2—relatively unstable scope position
with the needle pointing toward the papilla and the shortest distance from the papilla;
ii) semi-long scope stably positioned in D1 junction with the needle often pointing
away the papilla, sometimes pointing toward hilum. As highlighted, each of these positions
has its specific pros and cons.
Dhir et al[73] have systematically evaluated the intrahepatic and extrahepatic approaches and found
the intrahepatic approach to be associated with higher postprocedure abdominal pain,
longer procedure time, and longer hospital stay. Other studies have also voiced that
the extrahepatic route has better technical success and lower adverse events than
the intrahepatic route.[74]
[75]
[76] Overall, the technical success of the extrahepatic approach is 87% compared with
65% of the intrahepatic approach. The adverse events rate was also higher in the intrahepatic
route (17 vs 8%). The logistic regression analysis has shown that the choice of the
access route is an important predictor of adverse events.[77] Therefore, the consensus group has opined that the extrahepatic approach should
be the preferred route for EUS-RV.
SGEI recommends that for the transhepatic approach, a segment 3 puncture is appropriate.
For the transduodenal approach, the puncture should be from the D1–D2 area, with the
needle directed toward the papilla.
Agreement: 100%. Level of evidence: IV. Grade of recommendation: D.
As highlighted earlier, puncturing the B2 segment for the intrahepatic approach makes
guidewire negotiation straightforward. However, in the unusual circumstance of failure
to negotiate across the papilla, a salvage HGS cannot be performed from a B2 segment
puncture. Hence, the working group agreed that the first approach should be a B3 segment
access.
Among the two stations of transduodenal extrahepatic access, the D2 station with shortened
scope has been shown to have better technical success than the semi-long D1 position.[76]
[78] Iwashita et al have proposed an algorithm for performing EUS-RV wherein the first
strategy is the extrahepatic short-scope D2 station approach, followed by D1 and then
intrahepatic.[78] This algorithmic approach had a success rate of 80%. Thus, the puncture should be
from D2 with the needle directed toward the papilla to optimize the technical success.
SGEI recommends that once the ERCP scope is at the papilla, cannulation should be
first attempted by the side of the guidewire exiting the papilla.
Agreement: 100%. Level of evidence: IV. Grade of recommendation: D.
There are various techniques for cannulating the papilla once a guidewire has been
passed through it. The traditional “over the wire” rendezvous technique entailed grasping
the guidewire with a snare or foreign body and pulling inside the biopsy channel of
the duodenoscope. The wire is then gradually pulled out of the channel while simultaneously
pushing the guidewire at the mouth to minimize resistance. Once the guidewire is pulled
out of the channel, a cannula or sphincterotome is guided, and the papilla is cannulated
over the exiting wire. However, this is cumbersome and time-consuming. An easier alternative
is to cannulate the papilla by the side of the exiting wire (“along the wire”). As
the wire passes out of the papilla, it straightens the intramural segment of the papilla,
and thus, passing a cannula parallel to this wire becomes easy. Sometimes fluoroscopy
can be used to align the axis of the cannula/sphincterotome to the exiting guidewire.[79] There are no comparative data between the two techniques. Most studies have described
the “over the wire” technique, while some have described the “along the wire” technique.[80]
[81] The working group opine that for cannulation in EUS-RV, the “along the wire” technique
should be attempted first as it is easy and succeeds most of the time.
A novel “hitch and ride” technique for cannulation was also described, wherein a handmade
catheter with a slit at the tip was designed. The slit helped in the anchorage of
the catheter over the wire (“hitch”) and then glid the catheter (“ride”) over the
exiting wire.[82]
