Intra-abdominal vagal blocking (VBLOC therapy): Clinical results with a new implantable medical device

Background: A new medical device uses high-frequency electrical algorithms to create intermittent vagal blocking (VBLOC therapy). The aim is to assess the effects of vagal blocking on excess weight loss (EWL), safety, dietary intake, and vagal function. Methods: An open-label, 3-center study was conducted in obese subjects (body mass index [BMI] 35-50 kg/m²). Electrodes were implanted laparoscopically on both vagi near the esophagogastric junction to provide electrical block. Patients were followed for 6 months for body weight, safety, electrocardiogram, dietary intake, satiation, satiety, and plasma pancreatic polypeptide (PP) response to sham feeding. To specifically assess device effects alone, no diet or exercise programs were instituted. Results: Thirty-one patients (mean BMI, 41.2 ± 1.4 kg/m²) received the device. Mean EWL at 4 and 12 weeks and 6 months after implant was 7.5%, 11.6%, and 14.2%, respectively (all P < .001); 25% of patients lost >25% EWL at 6 months (maximum, 36.8%). There were no deaths or device-related serious adverse events (AEs). Calorie intake decreased by >30% at 4 and 12 weeks and 6 months (all P ≤ .01), with earlier satiation (P < .001) and reduced hunger (P = .005). After 12 weeks, plasma PP responses were suppressed (20 ± 7 vs 42 ± 19 pg/mL). Average percent EWL in patients with PP response <25 pg/mL was double that with PP response >25 pg/mL (P = .02). Three patients had serious AEs that required brief hospitalization, 1 each for lower respiratory tract, subcutaneous implant site seroma, and Clostridium difficile diarrhea. Conclusions: Intermittent, intra-abdominal vagal blocking is associated with significant EWL and a desirable safety profile.