Predictive factors for clinical improvement with Enterra gastric electric stimulation treatment for refractory gastroparesis

Abstract

The objectives of this study were to determine the clinical response to Enterra gastric electric stimulation (GES) in patients with refractory gastroparesis and to determine factors associated with a favorable response.

Methods: This study was conducted in patients undergoing Enterra GES for refractory gastroparesis. Symptoms were scored before and after GES implantation using the Gastroparesis Cardinal Symptom Index (GCSI) with additional questions about abdominal pain and global clinical response.

Results: During an 18-month period, 29 patients underwent GES implantation. Follow-up data were available for 28 patients, with average follow-up of 148 days. At follow-up, 14 of 28 patients felt improved, 8 remained the same, and 6 worsened. The overall GCSI significantly decreased with improvement in the nausea/vomiting subscore and the post-prandial subscore, but no improvement in the bloating subscore or abdominal pain. The decrease in GCSI was greater for diabetic patients than idiopathic patients. Patients with main symptom of nausea/vomiting had a greater improvement than patients with the main symptom of abdominal pain. Patients taking narcotic analgesics at the time of implant had a poorer response compared to patients who were not.

Conclusions: GES resulted in clinical improvement in 50% of patients with refractory gastroparesis. Three clinical parameters were associated with a favorable clinical response: (1) diabetic rather than idiopathic gastroparesis, (2) nausea/vomiting rather than abdominal pain as the primary symptom, and (3) independence from narcotic analgesics prior to stimulator implantation. Knowledge of these three factors may allow improved patient selection for GES.

Figures

Fig. 1

Effect of Enterra gastric electric stimulation on patient’s global clinical response. Overall, 14 of the 28 patients (50%) undergoing GES felt improved, 8 (29%) remained the same, and 6 (21%) felt that their symptoms had worsened. Of the 12 diabetic patients, 7 (58%) felt improved, 3 (25%) remained the same, and 2 (17%) worsened. Of the 16 idiopathic patients, 7 (44%) were improved, 5 (31%) remained the same, and 4 (25%) worsened

Fig. 2

Effect of GES treatment on GCSI subscores. GES resulted in a significant decrease in the nausea/vomiting subscore from 3.8 ± 0.2 to 2.6 ± 0.3 (P < 0.01). The post-prandial fullness subscore significantly decreased from 3.4 ± 0.2 to 3.0 ± 0.3 (P < 0.05). There was no change in the bloating subscore: it remained at 2.6 ± 0.3. Results graphed as mean ± SEM

Fig. 3

Effect of GES based on gastroparesis subtype and main symptom. Of the 28 patients in the study, 22 described nausea and vomiting as the main symptom. For these patients, Enterra stimulation led to a significant decrease in the GCSI from 3.4 ± 0.2 to 2.7 ± 0.2 (P < 0.05). Of the six patients that described their primary symptom as abdominal pain, the GCSI was unchanged. Results graphed as mean ± SEM. The favorable effect of Enterra GES on clinical symptoms was primarily seen in diabetic patients with main symptom of nausea and vomiting. Results graphed as mean ± SEM

Fig. 4

Effect of narcotic analgesic use on clinical response to GES. Use of regular narcotic analgesics reduced the response rate. Thirteen patients were taking some form of narcotic agents at the outset of the study. The 15 patients not using narcotics experienced a significant decrease in the GCSI from 3.8 ± 0.2 to 2.1 ± 0.4 (P < 0.01), while those on narcotics had no change in the GCSI (3.1 ± 0.3 to 3.1 ± 0.2). Results graphed as mean ± SEM