Preserved Antral Contractions Measured by Wireless Motility Capsule Are Associated With Lower Response Rates to Gastric Per-Oral Endoscopic Myotomy in Patients With Idiopathic Gastroparesis.

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.