title: Mechanisms of symptomatic improvement after gastric electrical stimulation in gastroparetic patients.
abstract: The aims were to investigate the effects of gastric electrical stimulation (GES) on autonomic function, gastric distention and tone, and central control mechanisms in gastroparetic patients. Ten gastroparetic patients refractory to standard medical therapy participated in this study and data were collected at baseline, within two weeks before surgery for implantation of GES system, and at follow-up sessions between 6 and 12 weeks after GES therapy was initiated. In each session, electrocardiogram, electrogastrogram (EGG) and gastric barostat measurements were conducted before and after a caloric liquid meal. Positron Emission Tomography (PET) brain scans were performed on a separate day. During GES therapy there was a significant increase in the discomfort threshold for mean pressure from 21 mmHg at baseline to 25 mmHg at follow-up, and for mean volume from 561 mL to 713 mL. A significant increase in the postprandial EGG power (amplitude) was observed between baseline and follow up. The sympathovagal balance was significantly decreased after GES therapy, indicating a significant increase in vagal activity. The cumulative PET data showed an increase in quantitative radioactive counts relative to the standardized data base in both the thalamic and caudate nuclei after chronic GES therapy. We conclude that our data suggest that the symptomatic improvement achieved by GES in gastroparesis is best explained by activation of vagal afferent pathways to influence CNS control mechanisms for nausea and vomiting accompanied by enhanced vagal efferent autonomic function and decreased gastric sensitivity to volume distention which enhances postprandial gastric accommodation.
authors.affiliation: Department of Medicine, University of Kansas Medical Center, Kansas City, KS, USA. richard.mccallum@ttuhsc.edu
authors.forename: R W
authors.initials: RW
authors.lastname: McCallum
authors.forename: R W
authors.initials: RW
authors.lastname: Dusing
authors.forename: I
authors.initials: I
authors.lastname: Sarosiek
authors.forename: J
authors.initials: J
authors.lastname: Cocjin
authors.forename: J
authors.initials: J
authors.lastname: Forster
authors.forename: Z
authors.initials: Z
authors.lastname: Lin
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001921:Brain / Q000000981:diagnostic imaging; D004599:Electric Stimulation Therapy; D004562:Electrocardiography; D005260:Female; D005746:Gastric Emptying / Q000502:physiology; D018589:Gastroparesis / Q000503:physiopathology / Q000628:therapy*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D019518:Postprandial Period; D011788:Quality of Life; D011877:Radionuclide Imaging; D016896:Treatment Outcome