Preserved Antral Contractions Measured by Wireless Motility Capsule Are Associated With Lower Response Rates to...

Wireless motility capsule (WMC) measures antroduodenal contractility and may help identify gastroparesis (GP) patients most likely to respond to gastric per-oral endoscopic myotomy (G-POEM). Contractile predictors of G-POEM success remain elusive, and WMC contractility data have not previously been studied for this purpose.

Refractory gastroparesis patients with WMC testing prior to G-POEM were retrospectively analyzed. Gastroparesis Cardinal Symptom Index (GCSI) before and after G-POEM, contraction count (Ct) and area under the pressure curve (AUC) from WMC were collected 1 h before and after gastric emptying time (GET). Decrease in GCSI ≥ 1 defined G-POEM response. Antral Ct < 29/h, AUC < 1358 and duodenal Ct < 36/h, AUC < 1456 defined diminished contractions. Contractility between responders and non-responders was compared using Pearson chi-square.

Eighty-five patients were analyzed (mean age 45, 88% female); 41 (48.2%) responded to G-POEM. Among all patients, antroduodenal contraction parameters were not associated with G-POEM response. Among idiopathic GP patients, those with preserved antral contractions by AUC were more likely to be non-responders (70% vs. 30%, p = 0.028), particularly in those with severely delayed GET (74% vs. 26%, p = 0.007). Conversely, idiopathic GP patients with diminished antral contractions by AUC were more likely to be responders (67% vs. 33%, p = 0.028).

In idiopathic gastroparesis, preserved antral contractions were associated with G-POEM non-response, while diminished antral contractions were associated with response. Diminished antral contractions may represent a phenotype of severe motor delay responsive to "passive" gastric emptying by G-POEM, whereas preserved antral contractility may indicate sensory neuroenteric dysfunction less amenable to pyloric intervention.