S1323 Optimal Parameters of Gastric Electrical Stimulation for Long-Term Symptom Control in Patients With Gastroparesis

INTRODUCTION: Gastric electrical stimulation (GES) with Enterra therapy is indicated for the treatment of drug-refractory gastroparesis (GP) symptoms. However, there is limited literature on recommended stimulation parameters and their association with long-term clinical outcomes. Our goal was to evaluate the differences in GES parameters and GP total symptom score (TSS) in 2 etiological groups of gastroparetic patients at the time of GES introduction and during follow-up visits. METHODS: Fifty-seven GES patient records were retrospectively reviewed. An interrogation of the GES system and assessment of GP symptoms were performed at the initiation of GES therapy and during follow-up visits. The default stimulation parameters remaining constant included a frequency of 14 Hz, a pulse width of 330 μs and an ON/OFF time of 0.1s/5s. The variable stimulation parameters were voltage, impedance/resistance, and current. A 5-point Likert scale (0—absent, 1—mild, 2—moderate, 3—severe, and 4—extremely severe) was utilized to assess the following GP symptoms: vomiting, nausea, early satiety, bloating, postprandial fullness, and abdominal pain. The TSS was calculated by adding the scores of the 6 GP symptoms with a maximum score of 24. At each follow-up visit, the GES parameters of voltage (V) and current (I) were adjusted based on the patient’s clinical presentation and recorded impedance value (R; normal range of 200–800 Ω). RESULTS: The mean age of patients was 44 ± 14 years, and 72% were female. The etiology for GP was diabetes mellitus in 72% and 28% were idiopathic. The mean duration of GP before the introduction of GES was 6 ± 4 years. The median time of follow-up visit was 47 months (range 5–73 months). A significant decrease was found within each individual symptom score along with the TSS at the most recent follow-up visit compared to the baseline (P < 0.0001 for all). Impedance (P < 0.0001), voltage (P < 0.0001), and current (P = 0.0001) increased significantly in the follow-up visit compared to the baseline visit (Table 1). There were no significant differences found between GES parameters in diabetic vs. idiopathic patients (Table 2). CONCLUSION: These findings suggest that a conservative approach to setting GES parameters yields optimal and sustained symptomatic control in GP patients regardless of their etiology. This “classic” programming of the system prevents early depletion of the device batteries, which allows longer utilization of GES therapy.Table 1.: Comparison of variable device stimulation parameters between baseline and the most recent follow-up visit. Device stimulation parameters reported as mean (standard deviation, or SD)Table 2.: Comparison of follow-up GES parameters and total symptom score based on the etiology of gastroparesis. Device stimulation parameters and total symptom score reported as mean (standard deviation, or SD)