1. Introduction

Gastric varices (GV) are a serious complication of portal hypertension, present in about 20% of cirrhotic patients compared to up to 85% with esophageal varices (EV).^1,2 Though less common, GV are associated with more severe bleeding, higher mortality, and increased rebleeding rates.^1,3 IGV1 (isolated fundal varices) and GOV2 (gastroesophageal varices extending into the fundus) carry the highest bleeding risk, with 2-year incidence rates of up to 78% and 55%, respectively.¹ (Figure 1)

Sarin’s classification is the standard system for categorizing GV into four types: GOV1 (extension of EV into the lesser curvature), GOV2 (into the fundus), IGV1 (isolated fundal), and IGV2 (elsewhere in the stomach).^1,2 GOV1 is most common (75%), followed by GOV2 (21%), IGV2 (4%), and IGV1 (<2%).¹ GV bleeding is more severe, harder to control, and more likely to recur, warranting early recognition and targeted treatment.

Unlike EV, which drain into the azygos system, GV form complex portosystemic collaterals via the gastrorenal or left inferior phrenic veins.^1,4 They may rupture at portal pressures below 12 mmHg due to differences in wall tension and shunt dynamics.^1,4 Their fundal location, thin walls, and high flow through large shunts increase bleeding risk, often without warning.

Management is challenging due to anatomical variability and limited trial data. Endoscopic cyanoacrylate injection (ECI) is the preferred treatment for cardiofundal varices (GOV2, IGV1), achieving high hemostasis rates.^1,2 EBL and sclerotherapy are less effective, with <50% hemostasis and rebleeding rates up to 63% over two years. ECI, while effective, carries embolization risks—particularly with gastrorenal shunts—and requires expertise. Access to glue is also limited. Radiologic options like TIPS and BRTO are used for refractory cases but have drawbacks such as hepatic encephalopathy or worsening of EV.^1,2 EUS-guided coiling has emerged as a promising alternative, allowing Doppler-guided coil placement with or without glue. It offers precise targeting and reduced embolic risk compared to direct glue injection.^3,7 While early data show high success rates, widespread use is limited by procedural variability and lack of randomized trials. This review explores the rationale, technique, and evidence supporting EUS-guided coiling in GV management.

2. Current Standards of Care

Initial management of bleeding gastric varices (GV) includes hemodynamic stabilization, vasoactive agents (e.g., octreotide or terlipressin), prophylactic antibiotics, and restrictive transfusion. Endoscopy within 12 hours is recommended for diagnosis and classification. Once stable, AGA and AASLD guidelines advise cross-sectional imaging (CT or MRI) to assess vascular anatomy and suitability for BRTO or TIPS.^2,8

Endoscopic cyanoacrylate injection (ECI) is first-line therapy for cardiofundal varices (GOV2, IGV1), supported by AGA, AASLD, Chinese, and Baveno VII guidelines due to its high hemostasis rates. However, its use is limited by glue availability, risk of systemic embolization—especially in gastrorenal shunts—and need for operator expertise.^2,8-10

BRTO is preferred in patients with a gastrorenal shunt and preserved liver function, while TIPS is indicated when endoscopic therapy fails or BRTO is not feasible. AASLD recommends repeat ECI every 2–4 weeks until obliteration, with surveillance at 3–6 months, then annually. Routine prophylaxis is not recommended, though high-risk patients may be considered.^2,8-10

EUS-guided therapies, though not yet widely adopted, are emerging as valuable options in specialized centers for high-risk or refractory cases.^3,7

3. Technique(s) Overview

EUS-guided coil embolization has emerged as an advanced modality for targeted treatment of bleeding and non-bleeding gastric varices (GV), particularly in cases with complex anatomy or high-risk shunts. Using Doppler-enhanced EUS, variceal inflow and outflow can be visualized in real time, enabling targeted therapy even in obscured or actively bleeding fields.^11,12

Coils (e.g., Nester^® and Tornado^®; Cook Medical, USA) are made of soft platinum wires embedded with synthetic Dacron fibers to enhance thrombogenicity. They act as a scaffold to promote hemostasis, either alone or in combination with cyanoacrylate, thrombin, or gelatin sponge. Coil use reduces sclerosant volume and systemic embolization risk, particularly in high-flow varices such as those associated with gastrorenal shunts. EUS also permits access to feeder vessels and deep submucosal varices not amenable to conventional endoscopic therapy.^11,12

This approach combines precision targeting, intraprocedural flow monitoring, and direct embolization, making it well suited for both primary and rescue therapy.

Standard Technique of EUS-Guided Coil Embolization

A. Pre-Procedure Preparation

The procedure is typically performed under general anesthesia or monitored anesthesia care, with the patient supine or in the left lateral decubitus position to optimize scope control. Instilling 100–200 mL of sterile water into the stomach may improve visualization by floating the varix.¹² Prophylactic antibiotics are commonly administered, and pre-procedural imaging (CT/MRI) is often used to delineate portosystemic shunts like gastrorenal shunts (GRS) for planning and embolic risk assessment.^11,13

B. Procedure Steps

Once the gastric fundus is visualized, EUS with color Doppler is used to identify the target varix or feeder vessel, typically seen as an anechoic, tubular submucosal channel. These vessels may appear dilated or tortuous. Doppler imaging is essential for assessing flow direction and hemodynamics before intervention.^13,14 A 19G or 22G FNA needle is then used to puncture the target, selected based on coil size: 

• 0.035-inch coils for 19G or

• 0.018-inch coils for 22G.^11,14

Needle placement is confirmed under direct EUS visualization. If needed, further confirmation can be achieved by 

• aspirating blood or 

• injecting 1–1.5 mL of distilled water to visualize hyperechoic bubbles under EUS—the preferred method to avoid trauma from suction¹¹

Once confirmed, hemostatic coils are deployed. Coils are often 20–30% larger than the varix diameter to ensure secure anchorage and thrombosis, but if the varices are very wide this is not always possible.^11,15 Deployment is performed under continuous EUS guidance with the needle tip in view, using a stylet or guidewire and steady pressure.^11,14 Fluoroscopy can be used during deployment but is not mandatory. 

Doppler flow can be reassessed post-deployment.¹³ If residual flow persists and immediate complete cessation of flow is desired, adjunctive agents (cyanoacrylate, thrombin, or gelatin sponge) may be injected through the same needle.^11,14,16 It should be noted that complete cessation of flow is not always possible to achieve during the procedure and that the formation of a stable thrombus takes time. 

When using glue, the needle is flushed with distilled water or 5% dextrose (not saline) to prevent premature polymerization and catheter blockage.¹¹

The procedure can be performed via either a transgastric or transesophageal route, the latter offering a tamponade effect that may reduce puncture-site bleeding.¹¹ Route selection depends on operator preference, anatomy, and variceal location. (Figures 2 and 3) 

C. Post-Procedure Care

Patients are monitored for immediate AEs such as bleeding, embolism, or pain.¹³ Follow-up is typically conducted at 1–3 months to assess variceal obliteration and recurrence, with further management guided by endoscopic and endosonographic Doppler findings or perceived rebleeding risk.¹³ Chavan et al. recommend initial follow up at 4 weeks, then at 3 months and every 6 months to monitor variceal status to perform flow studies, but this is often left to the operator and the patient to decide.¹¹

Technique Variations

A. Coil Embolization Alone

As described above, coil embolization involves EUS-guided deployment of thrombogenic platinum coils into the gastric varix or its feeder vessel without adjunctive agents. The coils induce mechanical thrombosis and flow disruption, resulting in clot formation and hemostasis. It avoids glue-related complications such as systemic embolization and endoscope damage. Careful patient and varix selection remains essential for optimal outcomes.^15,16

B. Coil Plus Cyanoacrylate Glue (Combination Therapy)

In combination therapy, the key technical modification from coil monotherapy is the sequential injection of cyanoacrylate glue following coil placement. After coil placement, a measured volume of glue is injected through the same FNA needle to promote complete obliteration. The coil acts as a scaffold, reducing glue migration and localizing polymerization within the varix. This technique typically uses less glue than direct endoscopic injection, thereby reducing, but not eliminating, the risk of systemic embolization. Immediate needle flushing with distilled water or 5% dextrose is essential post-injection to prevent in-lumen polymerization, which could occlude the catheter or damage the endoscope.^16-18

C. Coil Plus Thrombin Injection

This technique mirrors standard EUS-guided coil embolization up to variceal targeting, with the key distinction being the use of human thrombin instead of cyanoacrylate following coil placement. Once Doppler confirms reduced flow, thrombin is injected through the same FNA needle to enhance thrombosis and achieve obliteration. Unlike glue, thrombin does not polymerize, eliminating the need for rapid flushing and the risk of catheter occlusion or endoscope damage. It is reconstituted in saline and delivered in 1 mL aliquots (total dose: 600–10,000 IU), with injection stopped upon Doppler-confirmed flow cessation or reaching the maximum dose. This approach is particularly useful for patients at high embolic risk, those with glue allergies, or in settings without access to cyanoacrylate. Although data are limited, early series by O’Rourke et al. and Frost et al. report favorable technical success and safety, supporting its role as a viable alternative in select cases.^19,20 Of note, most centers do not have ready access to thrombin. 

D. Coil Plus Absorbable Hemostatic Agents (e.g., Gelatin Sponge)

In this variation, the key modification from coil monotherapy involves the adjunctive use of absorbable gelatin sponge (AGS) following coil placement. After Doppler-confirmed reduction in flow, a gelatin-based slurry is injected through the same needle to enhance thrombosis and promote complete variceal obliteration. Commercially available AGS products include GELFOAM^® (Pfizer, USA), SURGIFOAM^® (Ethicon, a Johnson & Johnson company, USA), and INSTASPON^® (manufactured in India by INSTASPON Pvt. Ltd.). The coil serves as a mechanical scaffold, while AGS reinforces hemostasis by limiting residual blood flow within the varix. Unlike cyanoacrylate, AGS does not pose a risk of catheter blockage or polymer-related embolization, and therefore does not require rapid needle flushing. Additionally, AGS is biodegradable and dissolves within days, making it especially useful in patients with high embolic risk or contraindications to glue. Doppler reassessment guides further management if persistent flow is detected, and operator judgment remains critical in timing the injection and selecting appropriate patients. This approach has also been applied in cases where TIPS or BRTO were not feasible or had failed. Structured EUS follow-up is used to confirm obliteration and monitor for recurrence.^21-22 However, while AGS is widely available in many surgical and interventional settings globally, its use in EUS-guided interventions remains relatively limited and center-specific, likely due to variations in operator familiarity, regulatory approvals, and material availability.

E. Feeder Vessel Embolization

In this variation of EUS-guided therapy, the target shifts from the submucosal variceal complex (SVC) to the feeder or perforator vessel supplying the gastric varices. Under EUS with color Doppler, the inflow vessel is identified—typically facilitated by Type 1 Arakawa anatomy where a dominant perforator is visualized.²³ In practice, feeder vessel embolization can be performed using the same core techniques as traditional SVC targeting, including coils, cyanoacrylate, or combination therapy, depending on operator preference and anatomy. In a recent comparative analysis by Samanta et al., this approach demonstrated comparable technical and clinical success to SVC targeting but required fewer coils and less glue, suggesting greater procedural efficiency. However, it is more technically demanding, necessitates anatomical mapping, and current clinical data remain limited.²³ In many patients, a feeder can be identified with careful evaluation. 

F. Access Route:
Transgastric vs. Transesophageal

EUS-guided variceal embolization can be performed via a transgastric or transesophageal route. The transgastric approach, involving direct puncture of the gastric fundus, is straightforward and allows direct visualization but may require the echoendoscope to be in a highly flexed position.  However, the transesophageal route may be advantageous when fundal varices are difficult to access, unstable during puncture, or visualization is limited. This route also provides a tamponade effect, as the needle traverses muscular layers, potentially reducing procedural bleeding. Transesophageal approaches allow a straight echoendoscope position and may be easier for the operator with regards to needle operation as well. Ultimately, the choice depends on anatomical factors and operator expertise, and both approaches require continuous needle-tip visualization to minimize complications. No studies have directly compared outcomes between these two approaches, and both are considered acceptable based on clinical context.¹¹

4. Clinical Efficacy and Safety Profile 

Technical and Clinical Success

EUS-guided coil embolization consistently achieves high technical success rates (98–100%) across studies, regardless of whether the approach involves coils, CYA, or combination therapy.^24,25 In a meta-analysis by McCarty et al., combination therapy had a 100% technical success rate, slightly outperforming glue (97%) and coil (99%) monotherapies (P < 0.001).¹⁵ Monotherapy is often favored in practice due to simplicity and ease of use. 

Clinical success—defined as immediate hemostasis and early bleeding control—varies by modality. Coil monotherapy achieves success rates of 88.6% to 94.7%, especially in patients with localized or low-flow varices.^14,15 CYA monotherapy performs similarly (91.3%–96%) but carries higher embolic risk in high-flow settings.^15,26

Combination therapy consistently delivers the best clinical outcomes. McCarty et al. reported a 98.2% success rate with coil + glue, compared to 96% for glue alone and 89.5% for coils (P < 0.001).¹⁵ In a randomized trial by Jhajharia et al., combination therapy achieved 100% obliteration vs. 92.3% with glue alone, using fewer sessions and significantly less glue (1.5 mL vs. 3.5 mL).²⁶

Alternative techniques also show promise. Coil plus thrombin injection yielded 95% technical and 85% clinical success in the prospective series by O’Rourke et al., with no thrombin-related complications.¹⁹ Coil with absorbable gelatin sponge (AGS) also demonstrated favorable results, although this is not widely performed. Bazarbashi et al. achieved 100% technical success and hemostasis, with no rebleeding at 9 months, versus rebleeding in 11 of 30 patients (38%) in the CYA group.²¹ Samanta et al. reported complete obliteration in 23 of 24 patients (95.8%) when targeting the feeder vessel, with lower rebleeding (2 of 24; 8.3%), fewer re-interventions (1 of 24; 4.2%), and reduced use of coils and glue, though further validation is needed.²³

Safety Profile and Adverse Events

EUS-guided coil embolization has a favorable safety profile, with AE rates ranging from 3% to 9.1%. Romero-Castro et al. reported minor GI bleeding in 9.1% of coil-only cases, with no systemic embolization.^27,28 Bhat et al. found a pooled AE rate of 7.2%, mostly transient pain and minor bleeding.^25,26 No major series have reported systemic embolization with coil monotherapy, though rare complications such as coil migration and puncture-site bleeding (~10%) have been noted.²⁹

CYA glue monotherapy carries higher AE risks, largely due to systemic embolization and device-related issues. Pulmonary embolism occurred in 47% of patients in Romero-Castro et al.’s study (but these patients were mostly asymptomatic).^27,28 Bick et al. reported a 20.3% AE rate, including splenic infarction (3%) and bacteremia (2–6%).³⁰ Device-related adverse events such as needle adhesion and endoscope blockage occurred in 1.4–2.7% of cases.^27,31

Combination therapy with coils and glue offers a safer profile than glue alone, with McCarty et al. reporting a 10% adverse event (AE) rate vs. 21% (P < 0.001), and Lobo et al. noting pulmonary embolism in 25% vs. 50% with glue alone (P = 0.144), likely due to coils limiting glue migration.^15,32 Across modalities, common AEs include transient abdominal pain (8–15%), fever (5–9%), and minor GI bleeding (6–50%), with major bleeding occurring in up to 10%; the use of real-time Doppler and controlled injection helps minimize these risks.^27,29 Alternative approaches are also well-tolerated: thrombin injection resulted in 0% AEs even in emergencies (Frost et al.), gelatin sponge use showed no complications in Ge et al. and only mild AEs in 4.7% of cases in Bazarbashi et al., while feeder vessel embolization preserved safety and reduced the need for coils and glue.^20-23

Long-Term Outcomes:
Rebleeding and Reintervention

EUS-guided therapies for GV—including coil embolization, CYA glue injection, and combination therapy—demonstrate varying long-term efficacy, with most follow-up data limited to 6–13 months.^15,16,33,34

Combination therapy (coil + glue) consistently shows superior outcomes. Rebleeding rates range from 4.8% to 14%, with McCarty et al. reporting a pooled rate of 14% versus 30% for glue alone and only slightly higher at 17% for coil monotherapy.¹⁵ Other studies reinforce this: Florencio de Mesquita et al. reported 5% rebleeding with combination therapy versus 24% for glue (P < .001), Chen et al. found 4.8% vs. 27.8% (P = .041), and Robles-Medranda et al. observed 3.3% vs. 20% (P = .04).^18,33,34 Of note, Bazarbashi et al. found higher rebleeding rates for combination therapy (14.9%) versus coils alone (10.5%), the difference was not statistically significant (P = .99).¹⁴

Reintervention rates are also lowest with combination therapy: McCarty reports 15%, compared to 26% for glue and 25% for coil monotherapy.¹⁵ Florencio de Mesquita found reintervention rates of 11.9% with combination therapy vs. 36.4% for glue (P = .03), while Robles-Medranda reported 83.3% did not need further reintervention vs. 60% with coil alone.^18,34

Glue monotherapy, while effective for initial hemostasis, has the highest long-term rebleeding rates—ranging from 24% to 57.9% in studies by Florencio de Mesquita, Chen, Mukkada, and Romero-Castro.^28,33–35 Reintervention rates range from 15% to 36%.^15,34 Coil monotherapy avoids glue-related embolic risks but offers modest long-term durability. Rebleeding rates range from 10.5% to 20%.^14,15,18 McCarty et al. reported a 25% pooled reintervention rate with coil monotherapy, though individual study data on reintervention are limited.¹⁵

Alternative techniques show early promise but are based on small cohorts. Thrombin injection, though based on a small cohort, showed promising results in the study by Frost et al., which included 8 patients—3 with active bleeding (2 of whom achieved hemostasis) and 5 treated electively, none of whom rebled during follow-up.²⁰ Gelatin sponge adjuncts, though based on limited data, yielded complete obliteration at 4 months in a single-patient case report (Ge et al.) and a 14.1% rebleeding rate among 10 patients in the Bazarbashi cohort, with most cases managed with re-coiling.^21,22 Feeder vessel identification with subsequent embolization showed similar durability with fewer coils and less sclerosant, improving efficiency without compromising outcomes.²³

Long-term outcomes depend on factors such as treatment indication, variceal anatomy, and technical precision (e.g., coil sizing, Doppler-confirmed obliteration).^14,15,33 Among current options, EUS-guided combination therapy provides the most durable control, with consistently lower rebleeding and reintervention rates. However, longer-term prospective studies are needed to confirm its sustained efficacy.

5. Advantages and Limitations of EUS-Guided Coil Therapies Compared to DEI and BRTO/TIPS

EUS-guided coil embolization, particularly when combined with cyanoacrylate, offers key advantages over traditional treatments like direct endoscopic injection (DEI), BRTO, and TIPS. Real-time Doppler guidance enables direct visualization of gastric varices and feeder vessels, allowing precise coil placement and immediate confirmation of obliteration. In contrast, DEI is a semi-blind technique with higher risks of incomplete obliteration and systemic embolization.³⁶ EUS-guided therapy also uses less cyanoacrylate (1.4 mL vs. 2.6 mL), reducing glue-related complications such as needle blockage and endoscope damage.^33,37

Compared to BRTO, EUS-guided therapy shows similar efficacy with fewer adverse events. A multicenter propensity-matched study reported comparable one-year bleeding rates (15.3% vs. 13.6%) and four-week obliteration rates (83.1% vs. 91.5%), but significantly fewer adverse events with EUS (5.1% vs. 22.0%; P = 0.007). BRTO was associated with higher rates of new or worsening ascites and esophageal variceal progression.³⁸ Unlike TIPS, which alters systemic hemodynamics and increases the risk of hepatic encephalopathy, EUS-guided therapy provides localized variceal treatment without portal decompression.^33,36

However, limitations exist. EUS-guided therapy had a higher reintervention rate than BRTO (28.8% vs. 5.1%; P = 0.001), likely due to incomplete obliteration of collateral vessels not addressed endoscopically.³⁸ Additionally, its adoption is constrained by limited availability of equipment and expertise. Variability in technique—including coil size, number, glue volume, and use of Doppler—highlights the need for procedural standardization.^15,36

In summary, EUS-guided therapy of gastric varices is a precise, minimally invasive, and safer alternative to DEI, with a favorable safety profile compared to BRTO and TIPS. Broader implementation will require standardized protocols, increased training, and prospective studies evaluating long-term efficacy and cost-effectiveness.

6. Future Directions 

As EUS-guided therapy gains traction in the management of gastric varices, several critical gaps remain. While early data support its safety and efficacy—particularly with coil embolization—large randomized trials comparing it to TIPS and BRTO are lacking, especially in patients with complex anatomy or advanced liver disease. Long-term outcomes beyond 12 months are also underreported. These may be difficult trials to conduct given the frequency of gastric varices as compared to esophageal varices.

Another major challenge is the lack of procedural standardization. Variability in coil type, size, number, adjunctive agents, and Doppler criteria highlights the need for consensus protocols to guide practice and training. Similarly, cost-effectiveness analyses are needed, particularly in resource-limited settings where access to cyanoacrylate or interventional radiology may be constrained.

The role of EUS-guided therapy in primary prophylaxis for high-risk varices remains largely unexplored. More data are needed to guide patient selection and preventive efficacy. Emerging techniques—such as biodegradable agents, molecular imaging, and AI-assisted Doppler interpretation—may improve targeting, precision, and scalability. Feeder vessel–targeted embolization also shows promise in reducing material use and procedural time.

In sum, while EUS-guided approaches represent a transformative advance in gastric variceal management, broader adoption will require standardized practices, comparative studies, and continued innovation.

7. Conclusion

Endoscopic ultrasound-guided therapy represents a promising targeted approach for managing gastric varices, offering improved precision and safety compared to conventional therapies. Combination therapy with coil and cyanoacrylate consistently demonstrates superior efficacy, with lower rebleeding and reintervention rates than monotherapies, although coils as monotherapy are also highly effective. Alternative adjuncts like thrombin, gelatin sponge, and feeder vessel embolization show promise but are supported by limited data.

While retrospective studies suggest EUS-guided therapy may be comparable—or even favorable to—BRTO and TIPS in select patients, high-quality, prospective trials are needed. Standardization of technique, broader training, and cost-effectiveness analyses will be essential for wider adoption. With continued research and refinement, EUS-guided coiling has the potential to become a central component of gastric variceal management. 

References

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