Central Nervous System Mechanisms of Nausea in Gastroparesis: An fMRI-Based Case-Control Study.

BACKGROUND/AIMS: Nausea is a major complaint of gastroparesis (GP), and the pathophysiology of this condition is poorly understood. Therefore, this study utilized fMRI to investigate the possible central nervous system (CNS) mechanisms of nausea in 10 GP patients versus 8 healthy controls (HCs). METHODS: Nausea severity was assessed on a 0-10 scale and presented as mean ± SD. Nausea was increased from baseline utilizing up to 30 min of visual stimulation (VS). Functional network connectivity was measured with fMRI at baseline and after 30 min of VS. fMRI data were preprocessed using statistical parametric mapping software. Thirty-four independent components were identified as meaningful resting-state networks (RSNs) by group independent component analysis. The Functional Network Connectivity (FNC) among 5 RSNs considered important in CNS nausea mechanisms was calculated as the Pearson's pairwise correlation. RESULTS: Baseline nausea score in GP patients was 2.7 ± 2.0 and increased to 7.0 ± 1.5 after stimulation (P < 0.01). In HCs nausea scores did not increase from baseline after stimulus (0.3 ± 0.5). When comparing GP patients to HCs after VS, a significant reduction (P < 0.001) in bilateral insula network connectivity compared to the right insula network was detected. No significant differences in connectivity were noted among the other RSNs. Additionally, the average gray matter volume was non-significantly reduced in the insula in GP patients compared to HC. CONCLUSIONS: The insula connectivity network is impaired in nauseated GP patients. This phenomenon could explain the susceptibility of GP patients to nausea or may have resulted from a state of chronic nausea.

The Long-Term Efficacy and Safety of Pyloroplasty Combined with Gastric Electrical Stimulation Therapy in Gastroparesis.

INTRODUCTION: Gastroparesis is delayed gastric emptying without mechanical obstruction. Symptomatic improvement can be 50-60% with gastric electrical stimulation. To address delayed gastric emptying, pyloroplasty was added. This study examines the long-term efficacy and safety of simultaneous gastric electrical stimulator implantation and pyloroplasty. METHODS: In this prospective single-arm trial conducted from 2012 to 2015, 27 [23 females; mean age 43 (22-63)] gastroparesis patients who underwent simultaneous gastric electrical stimulator implantation with Heineke-Mikulicz pyloroplasty were studied. Six (25%) underwent simultaneous robot-assisted pyloroplasty and gastric electrical stimulator implantation. Diagnosis of gastroparesis was based on the 4-h gastric emptying test defined as >60% retention of isotope at 2 h and >10% at 4 h. Total symptom scores assessing severity of nausea, early satiety, bloating, vomiting, post-prandial fullness, and epigastric pain were obtained at baseline and at follow-up visits, ranging from 3 to 38 months (mean: 17). RESULTS: Follow-up data from 24 patients were available for analysis. There was 71% improvement in total symptom score on follow-up. Mean retention decreased by 29.6 and 48.7% at 2 and 4 h and gastric emptying was normalized in 60%. There were no post-surgical complications. CONCLUSIONS: Combination of gastric electrical stimulator and pyloroplasty significantly accelerated gastric emptying and improved gastroparesis symptoms. Combining these two surgical therapies improves both subjective and objective endpoints in drug refractory gastroparesis.