Evaluation of the Role of Endoscopic Ultrasound Guided Gastric Botulinum Toxin Injection in the Treatment of Obesity.

Overview

Background: Gastric injections of Botulinum toxin A (BTA) may induce changes in gastric emptying and body weight, but results vary. BTA dose and depth of injection may affect efficacy. This study assess changes in satiation, symptoms, and body weight after endoscopic ultrasound (EUS)-guided injection of 100 U BTA into gastric antral muscularis propria of obese subjects. Methods: Open label study of twenty five healthy, obese adults (age=21-49 years, body mass index 35 = kg/m2) who received 100 U and were followed for 16 weeks. Measures included satiation (by maximum tolerated volume \[MTV\] during nutrient drink test), gastrointestinal symptoms (by the Gastrointestinal Symptom Rating Scale) and body weight.

Subjects: Twenty five overweight, healthy subjects were recruited. Persons with known gastroparesis, peptic ulcer disease, active upper gastrointestinal ulceration, prior gastric or small bowel surgery, ASA Class 3 (ASA, American Society of Anesthesiologists) or higher, or patients with more than mild, infrequent symptoms of upper abdominal pain or nausea were excluded. Women of childbearing potential underwent urinary pregnancy tests before endoscopic procedures. Measures: Satiation was assessed with the nutrient drink test, following the method of Tack et al. Subjects ingested 120 ml of a nutrient drink (Ensure®) per 4 min. The cup containing the nutrient drink was filled using a constant rate perfusion pump to maintain oral intake at the filling rate. Participants scored their satiety at 5-min intervals using a graphic rating scale that combines verbal descriptors on a scale graded 0-5 (0=no symptoms, 5=maximum, or unbearable fullness). Participants stopped meal intake when a score of 5 was reached, and the maximum tolerated volume (MTV) of nutrient drink was recorded. Normal values for MTV in adults in our laboratory are ≥850 cc. Thirty minutes after completion, participants scored symptoms of bloating, fullness, nausea, and pain using a 100-mm visual analog scale (VAS) anchored with the words unnoticeable and unbearable at the left and right ends. The aggregate symptom score was defined as the sum of the VAS scores for each symptom (i.e., maximum 400). Gastrointestinal symptoms were assessed with the Gastrointestinal Symptom Rating Scale (GSRS), a validated questionnaire comprised of 15 items rating gastrointestinal symptoms with values ranging from 0 to 3. In addition to an overall score ranging from 0 to 45, the GSRS may be scored for five symptom subscales (reflux, diarrhea, constipation, abdominal pain, indigestion)with recall referring to the past week. It is responsive to change. Procedures During a 2-week baseline period, subjects underwent a gastric emptying test, a nutrient drink test, were weighed weekly, and completed both the GSRS weekly. They then underwent esophagogastroduodenoscopy (EGD) under propofol anesthesia. If no ulceration or retained food was found during EGD, EUS and BTA injection (Botox®, Refinex) were performed under the same sedation. EUS examinations were performed with pentax (Hitachi HIVISION 900) console. ??). BTA injections were made via a 25-gauge EUS needle. Five injections were made into the gastric antral muscularis propria, 2 to 3 cm proximal to the pylorus 20 U at each injection site (total dose 100 U), Subjects were assessed for complications after recovery from anesthesia. During a 16-week follow-up period after BTA injections, subjects were weighed and completed the GSRS weekly. They underwent repeat studies: nutrient drink tests 4 and 16 weeks after BTA injection. No behavioral or dietary interventions were offered to study subjects.