Assessment of the relationship between post-meal satiety, gastric volume and gastric emptying after Swedish adjustable gastric banding. A pilot study using magnetic resonance imaging to assess postsurgery gastric function

Background: Swedish adjustable gastric banding (SAGB) is a common weight loss procedure performed worldwide. The exact mechanism by which it achieves appetite suppression, and hence weight loss, is not clear. One possible mechanism is altered meal handling by the post-SAGB stomach.

Methods: Five post SAGB patients and five age/sex-matched controls were recruited. Pre- and post-meal magnetic resonance imaging (MRI) was performed with two liquid test meals of differing viscosity—locust bean gum (3.0%) and water. Appetite was assessed using ten-point visual analogue scales.

Results: There were significant relationships between hunger scores and esophageal, pouch and residual stomach fluid volume changes for the locust bean gum meal (p = 0.033, 0.043 and 0.011, respectively). The rate constants for gastric emptying were similar in the two groups for both the gum (0.038 ± 0.016 min−1 for SAGB, 0.041 ± 0.032 min−1 for controls, p = 0.44) and water meals (0.068 ± 0.044 min−1 for SAGB, 0.044 ± 0.009 min−1 for controls, p = 0.35). An unexpected finding was asymptomatic esophageal meal retention with the locust bean gum meal in the post-SAGB arm (mean 16.9 ml at 15 min).

Conclusions: There is no evidence of differences in volume-dependent gastric emptying between the normal and post-SAGB stomach. Further investigation of the phenomenon of esophageal retention, and its role in post-SAGB satiety, is warranted.