Beyond the Snapshot: Overcoming GES Limitations to Characterize Gastric Phenotypes and Therapeutic Responses Using a...

Gastric emptying scintigraphy (GES) is considered the standard for differentiating gastroparesis from functional dyspepsia and other foregut disorders characterized by nausea and vomiting but provides only a brief physiologic snapshot that may not accurately reflect daily function. We utilized a non-invasive wireless patch system (WPS) to characterize multiday gastric myoelectrical activity, evaluate its relationship with GES, and assess changes following a therapeutic intervention.

Adults referred for GES for symptoms thought to represent gastroparesis were enrolled in a prospective study. Patients wore a WPS for up to 6 days, starting on the day of scintigraphy. Gastric myoelectrical activity was analyzed and categorized into relatively weak, relatively moderate, and relatively strong activity phenotypes. A subset of patients underwent repeat monitoring following individualized therapeutic interventions (e.g., anti-emetics, proton pump inhibitors, lifestyle changes).

Forty-eight patients (mean age 44; 79% female) completed the study. GES identified delayed gastric emptying in 18%, rapid in 22%, and normal in 60% of subjects. During the 4-h concurrent GES window, gastric activity in patients with delayed emptying was lower, but this difference did not reach statistical significance (p = 0.08). When compared to the full multiday recording period, GES results showed no correlation with the myoelectric readings. Significant day-to-day variability was observed, both random and systemic. In the latter category, a "Test-Day" dip was observed with gastric activity lowest on Day 1 (GES test day) and increasing significantly on subsequent days, stabilizing by Day 4 (p < 0.001). Healthy control subjects recorded during normal daily routines showed no such day-to-day variation. In the retesting cohort, anti-emetics produced robust increases in gastric amplitude, whereas PPIs showed minimal impact.

The WPS effectively captures distinct gastric phenotypes and quantifies physiologic responses to therapy in both gastric and intestinal regions, demonstrating its clinical utility as a robust tool for evaluating and managing foregut symptoms in real-world settings. Importantly, the multiday WPS highlights significant day-to-day physiologic variability in gastric activity that extends beyond the single-day GES 'snapshot'.