IBC Oxford Oral Abstract 64 - Unravelling the enigma of post-sleeve differential liquids tolerance: a time-resolved MRI study

Abstract Background Laparoscopic sleeve gastrectomy (LSG) is one of the most frequently performed bariatric procedures, being technically easier, providing a satisfactory weight loss with metabolic benefits. However, patients reported a wide range of tolerance to fluids after surgery. They specifically mentioned water as the most difficult compared to other fluids. The underlying mechanisms of this phenomenon remain poorly understood. This study uses dynamic MRI to study the relationship between liquid tolerance post-LSG and the patterns of gastric motility. Methods Seventeen Egyptian patients underwent LSG, followed by assessments of liquids tolerance using dynamic MRI at one and six months postoperatively. Patients reported their tolerance to fluids separately and classified tolerance as normal, difficult, or intolerant. MRI was performed twice, once after consumption of 50 cc of water within a maximum period of 5 min, then after consumption of 50 cc of sugar-free juice, measuring the dynamics of gastric motility through detecting antral contraction wave height, frequency, velocity, and sleeve transit time. Results 10 patients (58.8%) experienced reduced water tolerance when asked one month postoperatively, while only a single patient (5.9%) reported difficulty with juice intake. Improved water tolerance was reported by most patients six months following surgery; the difficult tolerance group dropped to three (17.6 %) patients. All patients tolerated juice without issues. MRI findings detected a different gastric response to water and juice. At the beginning, water-induced contractions were lower in height but more frequent. On the other hand, waves induced by juice consumption had a higher contraction with a slower frequency. Antral contraction frequency decreased over time for both fluids (P < 0.001), but contraction wave height and velocity increased, particularly for water (P < 0.001). MRI also detected an increase in sleeve transit time, indicating a delayed but more regulated emptying pattern. Better water tolerance correlated with these motility adaptations, suggesting that early postoperative intolerance is related to changes in gastric motility rather than anatomical abnormalities. Conclusion Patients in their early postoperative phase following sleeve gastrectomy reported a significantly different tolerance to fluids, with water being less tolerated than juice. This may be attributed to changes in gastric dynamics in response to fluids with different physicochemical properties, rather than anatomical restrictions. Adaptation occurs with time, evidenced clinically by improved water tolerance, and in MRI by changes in the dynamics of gastric contractions making dynamic MRI a valuable tool in understanding post-LSG dynamic gastric changes.