stomach pacemaker for weight loss

Gastric Neuromodulation for Obesity

Abeezar I. SarelaConsultant in Upper GI & Bariatric Surgery

St James’s University Hospital & The Nuffield HospitalLeeds, UK

Gastric Neuromodulation(Electric Stimulation)

for Obesity

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Agenda

• Bariatric surgery: why gastric electrical

stimulation (GES)?

• Understand gastric electrophysiology

• Trace evolution of GES for obesity

• Currrent status of GES for obesity


Surgery for Obesity

• Global epidemic of obesity• Bariatric surgery is the only effective and

sustained treatment for morbid obesity• Bariatric surgery resolves diabetes and

other co-morbidity and saves lives• Laparoscopic surgery has significant

advantages over open procedures• Surgical morbidity and mortality are very

low in experienced units


But……..

• Aetiology of obesity is multi-factorial

• Bariatric surgery is not a cure for obesity

• Substantial incidence of weight regain

• Definite short, medium and long-term risks with all bariatric operations


The Search is On….

• Behaviour modification

• Monitor activity and eating pattern

• Adjustable parameters

• Technology-friendly

• Low surgical risk

• Wide applicability


Gastric Neuromuscular Function

• Gastric slow waves (Phasic): 3/min

• Tonic spikes superimposed on slow waves result in smooth muscle contraction

Soffer et al. Aliment Pharmacol Ther 2009;30:681-694


Gastric Electrical Stimulation (GES)

Gastric Pacing:• Entrain slow waves• Low-frequency + Long duration• Implantable Pulse Generator

(IPG) not available

Implantable GES• High frequency + Short duration• Slow waves not altered• Neural stimulation

Clinically Used GES is NOT pacing


Implantable Gastric Electrical Stimulators


Implantation of Gastric Electrodes


Features

• Behaviour modification

• Stimulation parameters

– Fixed vs. Adjustable

• Duration of stimulation

– Constant vs. Episodic

• Intelligent sensing


How does it work?

Short pulse-width and high frequency electrical stimulation

– Increases afferent vagal activity– Blocks efferent vagal activity– Gastric distention– Inhibits post-prandial antral contractions– Slows gastric emptying – Inhibition of post-prandial gastric slow waves


Transcend IGS™ SystemTransneuronix - Medtronics

•800 patients world-wide•10 years follow-up•35% excess weight loss


Transcend IGS™ - SHAPE Trial

• Randomised, placebo-controlled, double-blind trial

• 190 patients at 8 centres

• Primary end point: >10% EWL

– %EWL: Active vs. Sham• 11.8±17.6% vs. 11.7±16.9%

– EWL>20%: Active vs. Sham• 27% vs. 16%

Shikora et al. SOARD 2009

WITHDRAWN


MetaCure (2003; CE Mark 2006)

TANTALUS™ - Diabetes Control Technology

• 13 patients

• 3 months therapy

• Weight 104 kg 100 kg

• HbA1c 8.0 6.9

• Glucose 175mg/dl 127mg/dl

Bohdjalian et al. Surg Endosc. 2009


EnteroMedics (2002)

VBLOC™ Therapy


VBLOC™ - EMPOWER Trial• Multi-centre• 1 year double-blind, 4 years open-label• 2:1 randomization• 300 subjects, BMI 35-45 kg/m2


EnteroMedics - VBLOC™

• CE mark - 2009

• VBLOC Therapy - Maestro system

– pending FDA approval

– USA commercialization in 2010

?


Consumption - Expenditure Wt Change=

Gastric Stimulation• Creates early sensation of satiety• Reduces desire to eat between meals• Reduced meal volume

Patient Support System• Tracks & reports eating events• Tracks & reports exercise trends• Useful diagnostic for sleep disorders • Supports behavior modification

Low Impact• Excellent safety profile • Minimal lifestyle changes

• No special diets• No vitamin supplements

IntraPace: Abiliti™


GSA102 Analyzer

P102 Programmer

W102 Programmer

Wand

LGS102 Stimulator

LGL102

Lead

IntraPace: abiliti™


Endoscopy 6 Months Post-Implant


Unpublished data

Study Population

Number ofSubjects

30

Gender 25 Females / 5 Males

Age (years)Mean, range

40 (20 to 60)

Weight (lb)Mean, range

284.6 (213.4 to 370)

Excess weight (lb)

124.6 (72.9 to 177.5)

BMIMean, range

43.8 (32.5 to 55)


Abiliti™: Weight Loss

Unpublished data


Conclusions

• Licensed (very shortly) in Europe and USA

• Attractive features

– Diet & Behaviour modification

– Intelligence

– Adjustment

• Convincing potential for weight control

• Diabetes resolution


Emerging Paradigms in Obesity Therapy

• Super-Obesity: Conventional Bariatric

Surgery e.g. laparoscopic gastric bypass

• Less Severe Obesity

– Classes 1 and 2

– Class 3 with BMI<45 kg/m2

• Gastric Electrical Stimulation

• Endoscopic bariatric procedures

stomach pacemaker for weight loss

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