Supplementary material from "Quantification of gastric emptying caused by impaired coordination of pyloric closure with antral contraction: a simulation study"

Proper coordination of gastric motor functions is required for healthy gastric emptying. However, pyloric function may be impaired by functional disorders or surgical procedures. Here, we show how the coordination between the pyloric closure and the antral contraction affects the emptying of liquid contents. We numerically simulated fluid dynamics using an anatomically realistic gastrointestinal geometry. Peristaltic contractions in the proximal stomach resulted in gastric emptying at a rate of 3–8 ml min⁻¹. When the pylorus was unable to close, the emptying rate increased to 10–30 ml min⁻¹, and instantaneous retrograde flow from the duodenum to the antrum occurred during the antral relaxation. Rapid emptying occurred if the pylorus began to open during the terminal antral contraction, and that emptying rate was negative if the pylorus only opened during the antral relaxation phase. Our results showed that impaired coordination between the antral contraction and the pyloric closure can result in delayed gastric emptying, rapid gastric emptying and bile reflux.