Treating an oft-unrecognized and troublesome entity: using gastric electrical stimulation to reduce symptoms of malignancy-associated gastroparesis.

PURPOSE: Malignancy-associated gastroparesis (MAG) is a cause of morbidity in cancer patients but therapies are lacking. Gastric electrical stimulation (GES) is a novel treatment for MAG. Here, we describe 19 patients with MAG who underwent temporary GES placement. PATIENTS AND METHODS: Nineteen patients (6 males, 13 females) with various malignancies were reviewed for symptom scores and physiologic measures at baseline and after temporary GES placement. Symptoms were scored by three variables: nausea (N), vomiting (V), and GI total symptom score (TSS). Physiologic profiles were measured by solid and liquid phase gastric emptying scans (GET) at 1, 2, and 4 h and cutaneous electrogastrogram (EGG) and mucosal electrogram (EG) frequencies. Symptoms were measured for 5 days after temporary endoscopic GES placement, and measures were repeated post GES placement. RESULTS: Baseline GET results displayed delayed gastric emptying in 16 of 19 patients (mean solid retention 21.7 % at 4 h, normal <10 %; mean liquid retention 10.4 % at 4 h, normal <5 %). Cutaneous EGG (mean frequency 5.5 cpm) and EG (mean proximal frequency 5.1 cpm; mean distal frequency 5.1 cpm) showed evidence of neuromuscular dysfunction (normal 2.5-3.3 cpm). Symptom scores in N, V, and TSS showed statistically significant reduction after GES placement. CONCLUSION: A small sample of patients with MAG and receiving temporary GES experienced symptom improvement, with less change on gastric emptying time or gastric electrical amplitude or frequency. GES may provide a potential therapeutic option for symptomatic management of MAG and evaluation of these MAG patients after permanent GES placement is ongoing. Prospective studies of MAG using temporary and permanent GES may be warranted.

Abnormal initiation and conduction of slow-wave activity in gastroparesis, defined by high-resolution electrical mapping.

BACKGROUND & AIMS: Interstitial cells of Cajal (ICC) generate slow waves. Disrupted ICC networks and gastric dysrhythmias are each associated with gastroparesis. However, there are no data on the initiation and propagation of slow waves in gastroparesis because research tools have lacked spatial resolution. We applied high-resolution electrical mapping to quantify and classify gastroparesis slow-wave abnormalities in spatiotemporal detail. METHODS: Serosal high-resolution mapping was performed using flexible arrays (256 electrodes; 36 cm(2)) at stimulator implantation in 12 patients with diabetic or idiopathic gastroparesis. Data were analyzed by isochronal mapping, velocity and amplitude field mapping, and propagation animation. ICC numbers were determined from gastric biopsy specimens. RESULTS: Mean ICC counts were reduced in patients with gastroparesis (2.3 vs 5.4 bodies/field; P < .001). Slow-wave abnormalities were detected by high-resolution mapping in 11 of 12 patients. Several new patterns were observed and classified as abnormal initiation (10/12; stable ectopic pacemakers or diffuse focal events; median, 3.3 cycles/min; range, 2.1-5.7 cycles/min) or abnormal conduction (7/10; reduced velocities or conduction blocks; median, 2.9 cycles/min; range, 2.1-3.6 cycles/min). Circumferential conduction emerged during aberrant initiation or incomplete block and was associated with velocity elevation (7.3 vs 2.9 mm s(-1); P = .002) and increased amplitudes beyond a low base value (415 vs 170 µV; P = .002). CONCLUSIONS: High-resolution mapping revealed new categories of abnormal human slow-wave activity. Abnormalities of slow-wave initiation and conduction occur in gastroparesis, often at normal frequency, which could be missed by tests that lack spatial resolution. Irregular initiation, aberrant conduction, and low amplitude activity could contribute to the pathogenesis of gastroparesis.