EUS-guided transmural treatment of afferent loop syndrome: a systematic review and meta-analysis

Afferent loop syndrome (ALS) is an uncommon but clinically relevant complication after pancreaticobiliary or upper gastrointestinal reconstruction, most often in patients with recurrent malignant disease. Endoscopic ultrasound-guided creation of a transmural bypass, either as gastroenterostomy or enteroenterostomy, has emerged as a minimally invasive alternative to surgery or percutaneous drainage. We aimed to systematically review the available evidence and provide a pooled descriptive analysis of the efficacy and safety of EUS-guided treatment for ALS.

A systematic review was performed in accordance with PRISMA principles. PubMed/MEDLINE, Embase and the Cochrane Library were searched up to 15 May 2025 for studies reporting EUS-guided gastroenterostomy or enteroenterostomy for ALS. Case reports, case series and observational studies with extractable outcome data were eligible. Data on study design, indication, stent type, technical success, clinical success, adverse events and follow-up were extracted and synthesized.

Twelve studies involving 134 patients were included. On crude analysis, technical success was achieved in 132/134 patients (98.5%), clinical success in 127/134 (94.8%), and adverse events were reported in 13/134 (9.7%). In the pooled random-effects analysis, the technical success rate was 93.5% (95% CI 87.1-96.8; I²=0%), the clinical success rate was 91.0% (95% CI 84.5-94.9; I²=0%), and the overall adverse-event rate was 14.6% (95% CI 9.1-22.5; I²=0%). Adverse events were mainly procedure-related pain, fever, stent misdeployment, peritonitis or intra-abdominal infection. Electrocautery-enhanced lumen-apposing metal stents were used in most studies, whereas fully covered self-expandable metal stents were used in a smaller subset. Reported follow-up ranged from 1 to 15 months.

EUS-guided transmural bypass represents a promising, minimally invasive, and technically feasible alternative for the management of ALS. However, given the retrospective nature and small sample sizes of the available evidence, larger comparative trials are warranted to define its definitive role.