307 MUCOSAL AMPLITUDE RATIO OF TEMPORARY ELECTROGASTROGRAPHY PREDICTS OUTCOME OF RESPONSE TO GASTRIC ELECTRICAL STIMULATION.

Introduction Gastric electrical stimulation (GES) is an accepted therapy for gastroparesis (GP) with chronic nausea and vomiting. Temporary GES is a new approach applying GES endoscopically via the gastric mucosa. We previously reported that the ratio of frequency to amplitude of the serosal EGG at the time of placement might correlate with outcome of permanent GES. We now investigated the hypothesis that the ratio of frequency to amplitude of the mucosal EGG (mEGG) at the time of temporary GES placement might predict outcome to therapy. Patients 149 patients (118 F, 31 M, mean age of 44 years) with the symptoms of GP and diagnosis: 82 idiopathic, 41 diabetic, and 26 postsurgical, underwent temporary GES (TempGES) as previously described (GIE, 2005). Methods Patients were assessed at baseline and after 3 days of TempGES in terms of symptoms of vomiting (V), nausea (N), and GI total symptom score (TSS). The average frequency (F), amplitude (A), frequency to amplitude ratio (MART), and subclasses of F/A (by low/high for each) were calculated and compared with the outcome by % V symptom change and by V change category as none, minimal, or marked; were compared by t -tests, correlation, and chi-square and reported as mean ± SE. Results After 3 days of TempGES, V score changed from 2.3 ± 0.1 to 0.5 ± 0.1, N score changed from 3.3 ± 0.1 to 1.2 ± 0.1, and TSS changed from 14.3 ± 0.3 to 5.3 ± 0.4 (all p t -tests). The correlation of mEGG frequency ( p = .11) or amplitude ( p = .33) to V was not significant alone, but the mucosal frequency to amplitude ratio (MART) correlated with percent change in V ( p p = .07). By V outcome subgroup: 26 patients (17%) had no change, 39 patients (26%) had minimal change, and 84 patients (56%) had marked change at 3 days. High F/high A corresponded with marked change in 9 of 11 patients (82%), but low F/low A corresponded with marked change in 30 of 62 patients (49%). Conclusions We conclude that mucosal recordings of EGG frequency and amplitude at the time of endoscopic electrode placement correlate with symptom outcomes of temporary GES.