Distinct Subgroups in Gastroparesis Defined by Simultaneous Body Surface Gastric Mapping and Gastric Emptying Breath Testing.

Background: Gastroparesis is a heterogeneous disorder with several contributing pathophysiologies. In this study, we used simultaneous body surface gastric mapping (BSGM) and gastric emptying breath testing (GEBT) to subgroup patients with gastroparesis based on dynamic spectral meal response profiles and emptying rate.

Methods: Patients with chronic gastroduodenal symptoms and negative gastroscopy underwent simultaneous BSGM and GEBT with 30 min fasting and 4 h postprandial recording. In addition to standard metrics, the BSGM 'meal response ratio' (MRR) compared amplitude in the first 2 h postprandially to the subsequent 2 h (lagged meal response ≤ 1).

Results: One hundred and forty-three patients underwent simultaneous BSGM and GEBT (79% female, median age 31 years, median BMI 23 kg/m²), of whom 36 of 143 (25.2%) had delayed gastric emptying. Those with a lagged meal response had longer T_1/2 (median 95.0 [IQR 59-373] vs. median 78.0 [IQR 31-288], p = 0.009) and higher rates of delayed emptying (42.9% vs. 16.7% p = 0.03). BSGM phenotypes identified in patients with delayed emptying were lagged meal response (25%), low gastric amplitude/rhythm stability (30.6%), elevated gastric frequencies (11.1%), and normal BSGM spectral analysis (33.3%). T_1/2 weakly correlated with worse total symptom burden score (r = 0.18, p = 0.03).

Conclusion: Combined BSGM and gastric emptying testing defines subgroups of gastroparesis based on several BSGM abnormalities, including a novel group with delayed postprandial onset of gastric motor activity in association with delayed emptying.