Real-time endoscopic tissue oxygen saturation imaging of the upper gastrointestinal tract: baseline values and association with gastrojejunal anastomotic ulcer healing.

BACKGROUND AND AIMS: Gastrojejunal anastomotic (GJA) ulcers are a common complication after Roux-en-Y gastric bypass (RYGB) and may be refractory to medical therapy. Impaired mucosal perfusion is suspected to contribute to non-healing ulcers, but no method exists to directly assess ischemia. We evaluated the feasibility of real-time endoscopic tissue oxygen saturation (StO2) imaging to quantify mucosal perfusion and its association with ulcer healing.

METHODS

In this prospective study, 51 adults were included: 18 with normal gastrointestinal anatomy, 26 with RYGB anatomy without complications, and a subgroup of 7 RYGB patients with confirmed GJA ulcers. StO2 was measured in the esophagus, stomach/pouch, duodenum/jejunum, and anastomotic sites using an endoscopic StO2 imaging system. Ulcer patients received maximal medical therapy and were reassessed by follow-up endoscopy. StO2 values were compared across regions and between healed and non-healed ulcers.

RESULTS

In normal anatomy, esophageal StO2 was lower than gastric and duodenal values, while stomach and duodenum were similar. In RYGB patients without complications, StO2 values were comparable across the pouch, anastomosis, and Roux limb. Among ulcers, healed sites had significantly higher StO2 than non-healed sites (p = 0.002). Healed ulcers exhibited StO2 near baseline anastomotic levels, whereas non-healed ulcers demonstrated markedly reduced StO2.

CONCLUSION

Endoscopic StO2 imaging is feasible and enables quantitative assessment of mucosal perfusion in both normal and post-RYGB anatomy. Low StO2 at GJA ulcers is associated with poor healing, highlighting its potential to identify ischemic ulcers that may benefit from early surgical intervention. However, given the small sample size, particularly in the ulcer subgroup, these findings should be considered preliminary and interpreted with caution. Larger studies are needed to validate StO2 thresholds and define its role in clinical decision-making after RYGB.