Impact of gastric per-oral endoscopic myotomy on static and dynamic pyloric function in gastroparesis patients

Background: Functional Lumen Imaging Probe (EndoFLIP) tests typically measure static pyloric parameters, but the pylorus exhibits phasic variations on manometry. Dynamic changes in pyloric function have not been quantified using EndoFLIP, and the impact of Gastric Per-Oral Endoscopic Myotomy (G-POEM) on static and dynamic pyloric activity in gastroparesis is unknown.

Methods: EndoFLIP balloon inflation to 30, 40, and 50 mL was performed to measure mean, maximum, and minimum values and variability in pyloric diameter and distensibility before and after G-POEM in 20 patients with refractory gastroparesis. The impact of phasic contractions on these pyloric measures was compared.

Key results: G-POEM increased mean (P < .0001) and maximum (P = .0002) pyloric diameters and mean (P = .02) and maximum (P = .02) pyloric distensibility on 50 mL EndoFLIP inflation but not intraballoon pressures or minimum diameters or distensibility. Temporal variability of pyloric diameter (P = .02) and distensibility (P = .02) also increased after G-POEM. Phasic coupled contractions propagating from the antrum through the pylorus were observed in 37.5% of recordings; other phasic activity including isolated pyloric contractions were seen in 23.3%. Variability of pyloric diameter and distensibility tended to be higher during recordings with phasic activity. Some pyloric responses to G-POEM were influenced by age, gastroparesis etiology, gastric emptying, and prior botulinum toxin injection.

Conclusions & inferences: Pyloric activity exhibits dynamic changes on EndoFLIP testing in gastroparesis. G-POEM increases maximal but not minimal diameter and distensibility with increased variations, suggesting this therapy enhances pyloric opening but may not impair pyloric closure. Phasic pyloric contractions contribute to variations in pyloric activity.