What are the current updates and guidelines for Endoscopic Ultrasound (EUS) procedures?

Update on Endoscopic Ultrasound

The most significant recent updates in EUS include expanded interventional applications with comprehensive consensus guidelines for drainage procedures, refined anticoagulation management protocols, and emerging diagnostic technologies including AI-assisted interpretation and contrast-enhanced imaging.

Anticoagulation Management for EUS Procedures

Risk Stratification

EUS procedures are classified based on bleeding risk 1:

• Low-risk procedures: EUS without sampling or interventional therapy 1
• High-risk procedures: EUS-guided sampling or any interventional therapy 1

Management of Antiplatelet Therapy

For high-risk EUS procedures in patients on P2Y12 receptor antagonists (clopidogrel, prasugrel, ticagrelor):

• Low thrombotic risk patients: Discontinue P2Y12 inhibitors 7 days before the procedure and continue aspirin 1
• High thrombotic risk patients (drug-eluting stents <12 months, bare metal stents <1 month): Continue aspirin and liaise with interventional cardiology regarding P2Y12 discontinuation 1
• Restart antiplatelet agents 1-2 days after the procedure 1

Management of Anticoagulation

For warfarin:

• Low thrombotic risk: Stop warfarin 5 days before high-risk EUS procedures, ensure INR <1.5 prior to procedure 1
• High thrombotic risk: Temporarily discontinue warfarin and bridge with low molecular weight heparin 1

For direct oral anticoagulants (DOACs):

• Last dose should be taken 3 days before high-risk EUS procedures 1
• For dabigatran with CrCl 30-50 mL/min: Last dose 5 days prior 1
• Omit morning dose on day of low-risk procedures 1

Interventional EUS: Consensus Guidelines

EUS-Guided Biliary Drainage (EUS-BD)

EUS-BD is recommended over percutaneous transhepatic biliary drainage after failed ERCP in malignant distal biliary obstruction when local expertise is available 2. The Asian EUS Group and ESGE have established comprehensive technical standards 1:

• Pre-procedural MRCP or CECT is mandatory to understand anatomy and plan the optimal approach 1
• Prophylactic antibiotics covering biliary flora (second-generation cephalosporin or quinolone) should be administered 1
• Technical success rates range from 82-97% with clinical success of 97% 3
• Overall adverse event rates remain at 23%, requiring experienced operators 3

EUS-Guided Pancreatic Duct Drainage (EUS-PD)

EUS-PD should only be considered in symptomatic patients with obstructed pancreatic ducts when retrograde endoscopic intervention fails or is not possible 2:

• Use 19-gauge needles for duct puncture with 0.035 inch or 0.025 inch guidewires with floppy tips 1
• Rendezvous techniques are preferred over transmural drainage due to lower adverse event rates 2
• Plastic stents without intervening side holes are recommended 1
• Tract dilation requires careful technique; electrocautery should be used sparingly to avoid pancreatitis, leak, or bleeding 1

EUS-Guided Gallbladder Drainage (EUS-GBD)

In high surgical risk patients, EUS-GBD should be favored over percutaneous drainage due to lower adverse event rates and need for re-interventions 2.

EUS-Guided Gastroenterostomy (EUS-GE)

EUS-GE is recommended as an alternative to enteral stenting or surgery for malignant gastric outlet obstruction in expert settings 2:

• Also appropriate for afferent loop syndrome, especially in malignancy or poor surgical candidates 2
• Offers advantages over traditional surgical approaches in selected patients 2

EUS-Guided Celiac Plexus Ablation

Repeated injections for chronic pancreatitis should be avoided to prevent major complications 1:

• Target regions must be clearly visualized in stable position throughout the procedure 1
• Needle tip visualization is mandatory to avoid vascular injury 1
• Serious adverse events (retroperitoneal bleeding, abscess, ischemia) are rare but can occur, particularly with bilateral techniques or excessive sessions 1
• Endoscopists competent in EUS-FNA can perform the procedure with appropriate visualization 1

Diagnostic Applications and Emerging Technologies

Current Diagnostic Capabilities

The National Comprehensive Cancer Network recommends EUS for early-stage disease detection, though accuracy varies significantly 4:

• Gastric cancer staging accuracy: 46.2% for T category, 66.7% for N category 4
• Diagnostic accuracy for subepithelial lesions ranges from 46-93% with fine-needle biopsy 4
• Contrast-enhanced EUS differentiates gastrointestinal stromal tumors from leiomyomas with >95% accuracy 4

Technological Innovations

High-frequency EUS miniprobes offer improved staging accuracy for early gastric cancer detection 4:

• AI algorithms for automated EUS image interpretation can improve staging accuracy and reduce operator dependency 4
• Elastography may improve diagnostic accuracy beyond conventional EUS for subepithelial lesion characterization 4
• Novel contrast agents are being developed for better tissue characterization 4

Novel Vascular Applications

Emerging EUS-guided vascular interventions include 4:

• Gastric variceal therapy 4
• Treatment of ectopic varices 4
• Portal pressure gradient measurements 4

Training and Competency Requirements

The Asian EUS Group emphasizes that interventional EUS procedures require specialized training beyond diagnostic EUS competency 1:

• Procedures should only be performed by experienced endoscopists capable of managing adverse events 1
• Wide variations in practice exist, necessitating standardized training protocols 1
• The RAND/UCLA appropriateness methodology was used to establish consensus guidelines combining scientific evidence with expert judgment 1

Critical Pitfalls to Avoid

Common complications and prevention strategies:

• Vascular injury: Always maintain needle tip visualization and avoid excessive injection sessions 1
• Post-procedure hemorrhage: Patients on antiplatelets/anticoagulants have increased bleeding risk; counsel appropriately 1
• Inadequate pre-procedural planning: Failure to obtain MRCP/CECT before EUS-PD significantly reduces success rates 1
• Inappropriate patient selection: EUS-BD and EUS-PD should only be attempted after failed conventional approaches 2
• Premature resumption of anticoagulation: Balance thrombotic and hemorrhagic risks, typically resuming 2-3 days post-procedure 1