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Introduction: Some patients who undergo gastric electrical stimulation (GES) for gastroparesis (GP) develop recurrent symptoms i.e.: vomiting, nausea, early satiety, bloating, and abdominal pain despite an initial good result, replete with a functioning stimulator and unbroken leads. This study evaluates treatment for these patients, which includes temporary stimulation at a new gastric location and if symptoms are relieved this is followed by implantation of new leads and stimulator. We expect symptom scores to significantly decrease in the control group; we hypothesize that the symptom scores will also show a significant decrease in the replacement group.

Patients: 15 patients with recurrent symptoms after placement of GES have undergone surgical insertions of a new gastric electrical stimulation (GES) system. Of the 15 replacement surgeries, 10 (67%) were female, 5 were male (33%) (mean age of all: 45), and 3 (20%) had diabetes-induced gastroparesis; the remainder (80%) were either idiopathic, post-surgical, or sarcoidosis-induced.

Of 87 patients without recurrent symptoms after placement of GES who have not needed a replacement, 15 were selected as the control arm, matched by the three variables of investigator-derived independent outcome score (IDIOMS), baseline symptom scores before initial GES implantation, and etiology of disease (i.e. diabetic or idiopathic).

Methods: Each patient met specific indications to receive GES replacement surgery. All patients had a preoperative diagnosis of either diabetic or idiopathic, drug-refractory, or post-surgical gastroparesis, and disordered gastric emptying with significant weight change. Patients with failed GES were evaluated over a 1-2 week period with insertion of a temporary endoscopic gastric stimulator. Patients with a positive response to temporary stimulation undergo GES replacement surgery. Common gastroparesis symptoms were evaluated before and after gastric pacemaker replacement using the Likert score system 0-4. These symptoms include vomiting, nausea, epigastric pain, early satiety and bloating.

Results: See Tables 1 and 2. Total score of symptoms improved for 12 out of the 15 (80%) patients that underwent the GES replacement surgery. The frequency, amplitude, freq/amplitude ratio (FAR), and gastric emptying times (GET) are displayed to reinforce physiological similarity between the two groups.

Conclusion: Trial gastric mucosal electrical stimulation followed by implantation of new leads and stimulator successfully salvages the majority of patients whose gastric electrical stimulator is no longer relieving symptoms.

Table 1 - Comparison of Mean Pre-Op and Mean Post-Op Symptom Scores

Replacement(n=15)	Mean of Pre-Op Scores	Mean of Post-Op Scores	Difference in Symptom Scores	p-value of Difference
Vomiting ±SD	3.2 ±1.3	2.1 ±1.3	1.2	0.001
Nausea ±SD	3.9 ±0.3	3.3 ±1.1	0.6	0.088
Early satiety ±SD	3.3 ±0.6	2.4 ±1.5	0.9	0.041
Bloating ±SD	3.3 ±0.6	2.5 ±1.5	0.8	0.057
Epigastric pain ±SD	3.6 ±0.6	3.3 ±1.4	0.3	0.24
Total Score ±SD	17.3 ±1.6	13.6 ±3.7	3.6	0.017
No Replacement (n=15)	Mean of Pre-Op Scores	Mean of Post-Op Scores	Difference in Symptom Scores	p-value of Difference
Vomiting ±SD	3.0 ±0.9	2.0 ±1.5	1.0	0.019
Nausea ±SD	3.2 ±1.2	3.0 ±0.9	0.2	0.5
Early satiety ±SD	3.1 ±1.0	2.4 ±1.1	0.7	0.019
Bloating ±SD	2.8 ±1.2	2.6 ±1.1	0.2	0.7
Epigastric pain ±SD	3.1 ±1.4	3.0 ±1.2	0.1	0.88
Total Score ±SD	15.8 ±3.6	12.3 ±3.5	3.5	0.011

Table 2 - Comparison of Mean EGG Values

	Replacement (n=15)	No Replacement (n=15)	p-value	Normal EGG values
Frequency ±SD	5.5 ±3.0	5.8 ±1.5	0.73	2.7-3.3
Amplitude ±SD	0.44 ±0.6	0.6 ±0.6	0.54	0.5
Freq/amp ratio ±SD	31.2 ±31.5	32.4 ±42.3	0.94	<10
Gastric emptying time (GET), 1;2;4 hr (%)	72, 49, 25	76, 48, 22	0.61, 0.96, 0.77
Total GET (%) ±SD	146 ±59	146 ±60	0.99

Table is displayed to reinforce physiological similarity between the two groups.