3 Predictors of symptom non‐responders to high‐frequency gastric electrical stimulation for refractory gastroparesis

Chronic high‐frequency gastric electrical stimulation (GES) has been shown to improve gastroparetic symptoms and quality of life (QOL) in up to 70% of patients with refractory gastroparesis (Gastroenterology 2003; 125:421–8). Little is known about factors associated with treatment failure. Clinical and gastric function data (gastric emptying test, GET; electrogastrogram, EGG) were extracted from a retrospective analysis of 87 gastroparetic patients (48 diabetic, 20 idiopathic and 19 postsurgical) who completed GES therapy (Enterra™ System, Medtronic) for at least 1 year. Total symptom score (TSS) (sum of severity of nausea, vomiting, early satiety, bloating, postprandial fullness, epigastric pain and burning using a 5‐point scale, 0 = non, 4 = extremely severe), quality of life (SF‐36 Health Status Survey questionnaire including physical composite score (PCS) and mental composite score (MCS)) and GET (4‐hour scintigraphy of a low‐fat meal) were examined at baseline and 1 year follow‐up. A non‐responder had <25% reduction in TSS and a responder was defined as having a ≥ 50% reduction in TSS after 1 year of GES therapy. Results:  Overall the non‐responder rate was 23% (10% in diabetic vs. 16% in postsurgical vs. 35% in idiopathic subgroup). Non‐responder rates were similar for men (22%) and women (23%) and age was not a factor. Compared to responders of GES therapy, non‐responders had similar mean baseline vomiting (2.6 vs. 3.2) and nausea scores (3.3 vs. 3.6) but a lower TSS (17.6 vs. 20.1, P < 0.05). Also non‐responders had less improvements in mean gastric retention both at 2 hours (+5.4 vs. ­8.7%) and at 4 hours (+4.0 vs. ­10.5%), less improvement in mean PCS (+2.0 vs. +12.4, P < 0.05) and gained less weight (­0.4 kg vs. +3.7 kg) than responders. 67% of non‐responders had an abnormal EGG (dysrhythmia >30% or decrease in postprandial EGG power) vs. 33% in responders. Non‐responders had more baseline mean tachygastria both in the fasting state vs. responders (26% vs. 11%, P < 0.05) and in the fed state (24% vs. 11%, P < 0.05) and less increase in postprandial EGG power (­1.3 dB vs. 1.6 dB, P < 0.05). Conclusions: The best symptom improvement achieved by high‐frequency GES therapy in refractory gastroparesis is in diabetics (10% treatment failure rate) and postsurgical (16% failure) while the worst results are in idiopathics (35% non‐responder rate). Baseline EGG abnormalities are predictors of poor symptomatic response to GES therapy and may be useful in developing a patient profile to optimize selection and expectations for GES therapy.