Gastric electrical stimulation improves outcomes of patients with gastroparesis for up to 10 years

The Investigation and Treatment of Diabetic Gastroparesis

PURPOSE

This review provides an update on the investigations and treatment options for gastroparesis.

METHODS

A comprehensive literature search of Medline, PubMed, Embase and OVID was conducted which included all systematic reviews and research articles that focused on the diagnosis, investigations and management diabetic gastroparesis.

FINDINGS

Dietary modifications and pharmacologic treatment with prokinetics to increase gastric motility form the mainstay of treatment. However, the use of prokinetics is limited by adverse effects and serious adverse effects, leaving metoclopramide as the only drug approved by the US Food and Drug Administration for the treatment of gastroparesis. Newer therapies, including motilin receptor agonists, ghrelin receptor agonists, and neurokinin receptor antagonists, are currently being investigated. Transpyloric stenting, gastric electrical stimulation, and gastric per-oral endoscopic myotomy provide mechanical options for intervention, and surgical interventions in severe intractable gastroparesis include laparoscopic pyloroplasty or gastrectomy.

IMPLICATIONS

Advances to better understand the pathophysiology and management of diabetic gastroparesis have been limited, especially with discordance between symptoms and severity of delay in gastric emptying. Established treatment options are limited; however, recent pharmacologic and surgical interventions show promise.

In Vivo Validation of a Less Invasive Gastrostimulator

Gastrointestinal stimulator implants have recently shown promising results in helping obese patients lose weight. However, to place the implant, the patient currently needs to undergo an invasive surgical procedure. We report a less invasive procedure to stimulate the stomach with a gastrostimulator. After attempting fully endoscopic implantation, we more recently focused on a single incision percutaneous procedure. In both cases, the challenges in electronic design of the implant are largely similar. This article covers the work achieved to meet these and details the in vivo validation of a gastrostimulator aimed to be endoscopically placed and anchored to the stomach.

Diabetic Enteropathy: From Molecule to Mechanism-Based Treatment

The incidence of the micro- and macrovascular complications of diabetes is rising, mirroring the increase in the worldwide prevalence. Arguably, the most common microvascular complication is neuropathy, leading to deleterious changes in both the structure and function of neurons. Amongst the various neuropathies with the highest symptom burden are those associated with alterations in the enteric nervous system, referred to as diabetic enteropathy. The primary aim of this review is to provide a contemporaneous summary of pathophysiology of diabetic enteropathy thereby allowing a "molecule to mechanism" approach to treatment, which will include 4 distinct aspects. Firstly, the aim is to provide an overview of the diabetes-induced structural remodelling, biochemical dysfunction, immune-mediated alterations, and inflammatory properties of the enteric nervous system and associated structures. Secondly, the aim is to provide a synopsis of the clinical relevance of diabetic enteropathy. Thirdly, the aim is to discuss the various patient-reported outcome measures and the objective modalities for evaluating dysmotility, and finally, the aim is to outline the clinical management and different treatment options that are available. Given the burden of disease that diabetic enteropathy causes, earlier recognition is needed allowing prompt investigation and intervention, which may lead to improvements in quality of life for sufferers.

Fluoroscopic gastric peroral endoscopic pyloromyotomy (G-POEM) in patients with a failed gastric electrical stimulator

Background

Gastric electrical stimulators (GESs) have been used to treat refractory gastroparesis in patients who fail initial therapies such as dietary modifications, control of psychological stressors and pharmacologic treatment. More recently, gastric peroral endoscopic pyloromyotomy (G-POEM) has emerged as a novel endoscopic technique to treat refractory gastroparesis. We present a case series of patients with refractory gastroparesis who failed treatment with an implanted GES that were safely treated with G-POEM performed under fluoroscopy as a salvage therapy.

Methods

Cases of G-POEM performed on patients with refractory gastroparesis who failed treatment with a GES were retrospectively reviewed. All G-POEM procedures were performed under fluoroscopic guidance with the GES still in place. Gastroparesis Cardinal Symptoms Index (GCSI) and gastric emptying scintigraphy were assessed before and after the procedure. Patients were followed up for up to 18 months post procedure.

Results

Five patients underwent G-POEM after failing treatment with a GES. Under fluoroscopy, the GES and their leads were visualized in different parts of the stomach. One GES lead was observed at the antrum near the myotomy site. All procedures were successfully completed without complications. Patients' GCSI decreased by an average of 62% 1 month post procedure. Patients also had notable improvements in gastric emptying 2 months post procedure.

Conclusion

In patients with refractory gastroparesis who have failed treatment with a GES, G-POEM can be safe and effective without removing the GES. To visualize the GES and avoid cutting GES leads during myotomy, the procedure should be performed under fluoroscopy.

Early Assessment of Cost-effectiveness of Gastric Electrical Stimulation for Diabetic Nausea and Vomiting

Background/Aims

Recurrent nausea and/or vomiting are common complications of diabetes mellitus. The conditions severely impact the quality of life of patients and often cause repeated admissions to hospital incurring significant healthcare costs. If standard treatment fails, gastric electrical stimulation (GES) may be offered in selected cases, as a minimally invasive, but expensive, therapeutic option. Our aims are to evaluate the clinical effect and the cost-utility of GES as a treatment for severe diabetic recurrent nausea and/or vomiting.

Methods

Among 33 diabetes patients implanted with GES because of recurrent nausea and/or vomiting, 30 were available for evaluation. The effect of treatment was assessed prospectively using symptom-diaries and the SF-36 questionnaires at baseline, after 6 and 12 months, and thereafter yearly. The number of days in hospital due to symptoms related to gastrointestinal dysfunction was calculated using hospital records 12 months prior to and 12 months after implantation.

Results

The surgical procedures were performed without mortality or major complications. Six months after surgery 78% of the respondents had at least 50% reduction in time with nausea and 48% had at least 50% reduction in days with vomiting. Symptom relief persisted at follow-up after at least 4 years. Quality adjusted life years improved after GES, which was cost-effective after 24 months.

Conclusions

GES reduces symptoms and improves quality of life in diabetes patients with recurrent nausea and/or vomiting. The procedure is supposed as cost-effective over a 2-year time horizon.

Diabetes and the Small Intestine

OPINION STATEMENT

Diabetes mellitus (DM) and its associated complications are becoming increasingly prevalent. Gastrointestinal symptoms associated with diabetes is known as diabetic enteropathy (DE) and may manifest as either diarrhea, fecal incontinence, constipation, dyspepsia, nausea, and vomiting or a combination of symptoms. The long-held belief that vagal autonomic neuropathy is the primary cause of DE has recently been challenged by newer theories of disease development. Specifically, hyperglycemia and the resulting oxidative stress on neural networks, including the nitrergic neurons and interstitial cells of Cajal (ICC), are now believed to play a central role in the development of DE. DE occurs in the majority of patients with diabetes; however, tools for early diagnosis and targeted therapy to counter the detrimental and potentially irreversible effects on the small bowel are lacking. Delay in diagnosis is further compounded by the fact that DE symptoms overlap with those of gastroparesis or can be confused with side effects from diabetes medications. Still, early recognition of the presence of DE is essential to mitigating symptoms and preventing further progression of complications including dysmotility and malabsorption. Current diagnostic modalities include manometry, wireless motility capsule (SmartPill™), and scintigraphy; however, these are not regularly utilized in clinical practice due to limited availability. Several medications are available for symptom relief in DE patients including rifaximin for small intestinal bacterial overgrowth (SIBO) and somatostatin analogues for diarrhea. While rodent models on stem cell therapy and alteration of the microbiome are promising, there is still a great need for further research on the pathologic underpinnings and development of novel treatment modalities for DE.

Gastric neuromuscular histology in patients with refractory gastroparesis: Relationships to etiology, gastric emptying, and response to gastric electric stimulation

BACKGROUND

The aims of this study were to describe the histology in gastroparesis, specifically to relate histopathology to etiology of gastroparesis (idiopathic and diabetic gastroparesis), gastric emptying, and clinical response to gastric electric stimulation.

METHODS

Full thickness gastric body sections obtained during insertion of gastric stimulator in gastroparetics were stained with Hematoxylin & Eosin, Masson Trichrome and immunohistochemical stains for Neuron-Specific Enolase and c-Kit.

KEY RESULTS

In all, 145 gastroparetics (71 diabetics, 71 idiopathic, 2 post-surgical, and 1 chronic intestinal pseudo-obstruction) had full thickness gastric body biopsies. A lymphocytic infiltrate was seen in the intermyenteric plexus in 22 diabetic and 23 idiopathic gastroparesis patients. Fibrosis was present in the inner circular layer in 13 diabetic and 15 idiopathics and in the outer longitudinal layer in 46 diabetic and 51 idiopathics. Diabetic gastroparesis had less ganglion cells (3.27±1.82 vs 4.81±2.81/hpf; P<.01) and less ganglia (0.90±0.44 vs 1.10±0.50/hpf; P=.01) than idiopathic gastroparesis. Interstitial cells of Cajal (ICC) count was slightly lower in the inner circular layer in diabetic than idiopathics (2.77±1.47 vs 3.18±1.34/hpf; P=.08). Delayed gastric emptying was associated with reduced ICCs in the myenteric plexus. Global therapeutic response to gastric electric stimulation was inversely related to ganglia/hpf (R=-.22; P=.008). In diabetics, improvements in nausea, vomiting, and abdominal pain were inversely related to fibrosis.

CONCLUSION AND INFERENCES

Histologic assessment of full thickness gastric biopsy specimens allows correlation of histopathology to the gastroparesis disease process, its etiology, gastric emptying, and response to gastric electric stimulation treatment.

Effectiveness and feasibility of robotic gastric neurostimulator placement in patients with refractory gastroparesis

Gastric neurostimulation (GNS) with Enterra^® therapy device (Medtronic, Minneapolis, MN) appears as the last resort for patients with refractory gastroparesis. Currently, the device has Humanitarian Use status by Food and Drug Administration, thereby requiring further investigation. We aim to describe its feasibility and clinical outcomes using robotic technique. From June 2014 to September 2016, 15 consecutive patients underwent robotic insertion of Enterra^® device. Patient demographics, comorbidities, and clinical outcomes including mortality, length of stay, readmission rates, reoperation and complications were retrospectively collected. Patients were also assessed based on a validated 14-point questionnaire regarding satisfaction with the operation, quality of life and symptomatic relief. Mean age was 41.6 years ± 13.8 and there were 11 females (73.3%). No mortality was reported. The annual hospital admissions were reduced after GNS (2.5 ± 4.1 vs. 3.6 ± 4.4, p = 0.004). The frequency of bloating (p = 0.029) and severity of emesis (p = 0.038), early satiety (p = 0.042) and bloating (p = 0.031) were reduced after GNS. The severity and frequency total scores were also improved after GNS (12.6 ± 1.4 vs. 18.1 ± 2.7, p = 0.008 and 12.9 ± 2.2 vs. 16.1 ± 1.1, p = 0.016, respectively). This is the first report describing the clinical experience with robotic insertion of GNS device. This approach is safe and feasible and seems to have similar long-term outcomes as laparoscopic technique. Potential advantages to robotic technique include enhanced dexterity and suturing of the device within gastric wall. Further experience with large prospective studies and randomized clinical trials may be warranted.

Electrical therapies for gastrointestinal motility disorders

Gastrointestinal (GI) motility disorders are common in clinical settings, including esophageal motility disorders, gastroesophageal reflux disease, functional dyspepsia, gastroparesis, chronic intestinal pseudo-obstruction, post-operative ileus, irritable bowel syndrome, diarrhea and constipation. While a number of drugs have been developed for treating GI motility disorders, few are currently available. Emerging electrical stimulation methods may provide new treatment options for these GI motility disorders. Areas covered: This review gives an overview of electrical therapies that have been, and are being developed for GI motility disorders, including gastroesophageal reflux, functional dyspepsia, gastroparesis, intestinal motility disorders and constipation. Various methods of gastrointestinal electrical stimulation are introduced. A few methods of nerve stimulation have also been described, including spinal cord stimulation and sacral nerve stimulation. Potentials of electrical therapies for obesity are also discussed. PubMed was searched using keywords and their combinations: electrical stimulation, spinal cord stimulation, sacral nerve stimulation, gastrointestinal motility and functional gastrointestinal diseases. Expert commentary: Electrical stimulation is an area of great interest and has potential for treating GI motility disorders. However, further development in technologies (devices suitable for GI stimulation) and extensive clinical research are needed to advance the field and bring electrical therapies to bedside.

Gastric Electrical Stimulation for Gastroparesis and Chronic Unexplained Nausea and Vomiting

OPINION STATEMENT

Gastroparesis is a heterogeneous clinical syndrome. Some patients have debilitating vomiting, weight loss, and dehydration, while others have effortless regurgitation of undigested foods or postprandial distress suggestive of functional dyspepsia. Gastric electrical stimulation (GES) has been proposed as an effective treatment option for patients with gastroparesis refractory to medical therapy. Evidence suggests that the clinically available device, a low-energy high-frequency GES, activates the vagal afferent pathways to influence the central control mechanisms for nausea and vomiting. Myoelectrical effects of the stomach are also involved. The results of randomized controlled trials (RCTs) for adults with diabetic and idiopathic gastroparesis are conflicting. There are no RCTs in adults with chronic unexplained nausea and vomiting (CUNV) with normal gastric emptying or in children with gastroparesis. However, there is increasing evidence from large unblinded studies showing the long-term efficacy in selected adults with gastroparesis. Selection criteria should be based on three categories: (a) underlying etiology, (b) clinical presentation and predominant symptoms, and (c) potential risk for complication. Significant abdominal pain, daily opiate use, and idiopathic gastroparesis are identified as negative predictors of success. Temporary GES has been utilized to identify patients who may benefit from surgical GES, but this strategy has yet to be proven in controlled studies. Objectives for this review are to highlight the mechanisms of action for GES, to look at the evidence for clinical efficacy, and to select patients who are likely to benefit.

Design and Implementation of a Less Invasive Gastrostimulator

Gastrointestinal stimulator implants have recently shown positive results in helping obese patients lose weight. However, to place the implant, the patient currently needs to undergo an invasive surgical procedure. Our team is aiming for a less invasive procedure to stimulate the stomach with a gastrostimulator. Attempts covered fully endoscopic implantation and, more recently, we have focussed on a single incision laparoscopic procedure. Whatever the chosen implantation solution, the electronic design of the implant system shares many challenges. This paper covers the work achieved to meet these.

Systematic review and meta-analysis: Gastric electrical stimulation for gastroparesis

BACKGROUND

Controlled trials of gastric electrical stimulation (GES) for gastroparesis reported no significant improvement in symptoms, while open label studies suggested substantial clinical benefits.

AIM

To determine if GES is effective in reducing symptoms in patients with gastroparesis.

METHODS

We searched PubMed and Embase for articles published in English (1990-2014) using "gastroparesis" as a search term restricted to "clinical trial". We included studies describing repeated patient-based symptom ratings before and during standardized treatments of at least one week duration.

RESULTS

Five studies randomly allocated patients to periods with or without GES. Total symptom severity (TSS) scores did not differ between these periods (0.17 [95% confidence interval: -0.06 to 0.4]; P=0.15). However, sixteen open label studies of GES showed a significant TSS decrease (2.68 [2.04-3.32]; Q=39.0; P<0.001). Other treatment modalities similarly improved TSS by 1.97 [1.5-2.44] for medical therapy (MED), by 1.52 [0.9-2.15] for placebo arms (PLA), and by 2.32 [1.56-3.06] for botulinum toxin (BTx). There were significant differences in baseline TSS ratings among these studies (GES: 6.28 [6.28-7.42]; MED: 4.76 [4.09-5.42]; PLA: 4.59 [3.77-5.42]; BTx: 6.02 [5.3-6.74]; Q=35.1; P<0.001). Meta-regression analysis showed these baseline differences to significantly impact TSS ratings during treatment (Q=71.8; P<0.001).

CONCLUSION

Independent of the treatment modality, baseline symptom severity impacts treatment results in gastroparesis. Considering the skewed population with refractory symptoms, regression to the mean likely contributes to the substantial discrepancies between the reported results of controlled and open label GES studies, raising questions about the use of GES outside of defined clinical trials.

Mini-laparotomy with Adjunctive Care versus Laparoscopy for Placement of Gastric Electrical Stimulation

We compared outcomes for two gastric electrical stimulation placement strategies, mini-laparotomy with adjunctive care (MLAC) versus laparoscopy without adjunctive care (LAPA). For electrode placement, the peritoneal cavity was accessed with either a single 2.5 to 3.0 cm midline incision (MLAC) or three trocar incisions (LAPA). For both groups, generator was placed subcutaneously over the anterior rectus sheath. For MLAC, adjunctive pain control measures were used for placement of both electrode and generator (transversus abdominus plane block). For LAPA, those that could not be completed by laparoscopy were converted to traditional open approach and kept in the analysis. MLAC (n = 128) resulted in shorter operative times than LAPA (n = 37) (median operative time: 87.5 vs 137.0 minutes, P ≤ 0.01). Hospital length of stay was also shorter for MLAC than for LAPA (median: 2.0 vs 3.0 days, P ≤ 0.01) without any increase in readmission rates to the hospital within 30 days of discharge (11.0 vs 16.2%, P = 0.39). After equalizing learning curves, these differences were even greater (median operative time: 84.5 vs 137.0 minutes, P < 0.01; median length of stay: 1.0 vs 3.0 days; P < 0.01) without increasing 30-day read-mission rates (9.1 vs 16.2%, P = 0.25). For implantation of gastric electrical stimulators, mini-laparotomy can result in improved outcomes when coupled with adjunctive pain control measures.

Treatment of gastrointestinal autonomic neuropathy

The symptoms caused by gastrointestinal autonomic neuropathy in diabetes mellitus is important to highlight since it affects a large proportion of people with diabetes, regardless of whether this is type 1 or type 2. Gastroparesis and general signs of bowel dysfunction, such as constipation, diarrhoea and abdominal pain are most often encountered and involve both pharmacological and non-pharmacological treatment options. This mini-review summarises a presentation given at the 'Diagnosis and treatment of autonomic diabetic neuropathy in the gut' symposium at the 2015 annual meeting of the EASD. It is accompanied by another mini-review on a topic from this symposium (by Azpiroz and Malagelada, DOI: 10.1007/s00125-015-3831-1 ) and a commentary by the Session Chair, Péter Kempler (DOI: 10.1007/s00125-015-3826-y ).

Effect of electrical stimulation of the lower esophageal sphincter in gastroesophageal reflux disease patients refractory to proton pump inhibitors

AIM: To evaluate the efficacy of lower esophageal sphincter (LES)-electrical stimulation therapy (EST) in a subgroup of patients that reported only partial response to proton pump inhibitors (PPIs) therapy, compared to a group of patient with complete response.

METHODS: Bipolar stitch electrodes were laparoscopically placed in the LES and connected to an implantable pulse generator (EndoStim BV, the Hague, the Netherlands), placed subcutaneously in the anterior abdominal wall. Stimulation at 20 Hz, 215 μsec, 3-8 mAmp in 30 min sessions was delivered starting on day 1 post-implant. Patients were evaluated using gastroesophageal reflux disease (GERD)-HRQL, symptom diaries; esophageal pH and esophageal manometry before and up to 24 mo after therapy and results were compared between partial and complete responders.

RESULTS: Twenty-three patients with GERD on LES-EST were enrolled and received continuous per-protocol stimulation through 12 mo and 21 patients completed 24 mo of therapy. Of the 23 patients, 16 (8 male, mean age 52.1 ± 12 years) had incomplete response to PPIs prior to LES-EST, while 7 patients (5 male, mean age 52.7 ± 4.7) had complete response to PPIs. In the sub-group with incomplete response to PPIs, median (IQR) composite GERD-HRQL score improved significantly from 9.5 (9.0-10.0) at baseline on-PPI and 24.0 (20.8-26.3) at baseline off-PPI to 2.5 (0.0-4.0) at 12-mo and 0.0 (0.0-2.5) at 24-mo follow-up (P < 0.05 compared to on-and off-PPI at baseline). Median (IQR) % 24-h esophageal pH < 4.0 at baseline in this sub-group improved significantly from 9.8% (7.8-11.5) at baseline to 3.0% (1.9-6.3) at 12 mo (P < 0.001) and 4.6% (2.0-5.8) at 24 mo follow-up (P < 0.01). At their 24-mo follow-up, 9/11 patients in this sub-group were completely free of PPI use. These results were comparable to the sub-group that reported complete response to PPI therapy at baseline. No unanticipated implantation or stimulation-related adverse events, or any untoward sensation due to stimulation were reported in either group and LES-EST was safely tolerated by both groups.

CONCLUSION: LES-EST is safe and effective in controlling symptoms and esophageal acid exposure in GERD patients with incomplete response to PPIs. These results were comparable to those observed PPI responders.

Adverse events of gastric electrical stimulators recorded in the Manufacturer and User Device Experience (MAUDE) Registry

The role of gastric electrical stimulation for patients with refractory symptoms of gastroparesis remains controversial. Open label studies suggest benefit while randomized controlled trials did not demonstrate differences between active and sham intervention. Using a voluntary reporting system of the Federal Drug Administration, we examined the type and frequency of adverse events.

METHODS

We conducted an electronic search of the Manufacturer and User Device Experience (MAUDE) databank using the keyword 'Enterra' for the time between January of 2001 and October of 2015. We abstracted information about the year of stimulator implantation, the year and type of adverse effect, the resulting intervention and outcome if available.

RESULTS

A total of 1587 entries described adverse effects related the GES. Only 36 of the reports listed perioperative complications. The vast majority described problems that could be classified as patient concerns, local complications, or system failure. The most common problem related lack or loss of efficacy, followed by pain or complications affecting the pocket site. A subset of 801 reports provided information about the time between system implant and registration of concerns, which gradually declined over time. More than one third (35.7%) of the reported adverse events prompted surgical correction.

CONCLUSION

The number of voluntarily reported adverse events and the high likelihood of repeated surgical interventions clearly demonstrate the potential downside of gastric electrical stimulation. Physicians considering this intervention will need to carefully weigh these risks and include this information when counseling or consenting patients.

Electrical stimulation for gastroesophageal reflux disease: current state of the art

Patients with gastroesophageal reflux disease (GERD) who are not satisfied with acid suppression therapy can benefit primarily from fundoplication, a surgical intervention. Fundoplication has been the standard surgical procedure for GERD. It is effective but is associated with adverse effects, resulting in a declining number of interventions, creating a need for alternative interventions that are effective, yet have a better adverse effect profile. One such alternative involves the application of electrical stimulation to the lower esophageal sphincter. A number of animal studies showed that such stimulation can increase resting lower esophageal sphincter pressure. An acute human study confirmed this effect, and was followed by two open-label studies, with a follow-up of up to 3 years. Results thus far show that the therapy is associated with a significant improvement in symptoms, a significant reduction in esophageal acid exposure, and a very good safety profile. This review will describe the evolution of electrical stimulation therapy for GERD, as well as the safety and efficacy of this intervention.

Gastric Electric Stimulation for Refractory Gastroparesis: A Prospective Analysis of 151 Patients at a Single Center

BACKGROUND

Gastric electric stimulation (GES) is used to treat patients with refractory gastroparesis symptoms. However, the effectiveness of GES in clinical practice and the effect of GES on specific symptoms of gastroparesis are not well delineated.

AIMS

To determine the effectiveness of GES for treatment for refractory symptoms of gastroparesis, the improvement in specific symptoms of gastroparesis, and clinical factors impacting on outcome.

METHODS

Enterra GES was used to treat refractory gastroparesis symptoms. Patients filled out a symptom severity questionnaire (PAGI-SYM) prior to insertion. At each follow-up visit, the patient filled out PAGI-SYM and assessed their therapeutic response using the Clinical Patient Grading Assessment Scale (CPGAS).

RESULTS

One hundred and fifty-one patients (120 females) with refractory gastroparesis (72 diabetic, 73 idiopathic, 6 other) underwent GES. Of the 138 with follow-up (1.4 ± 1.0 years), the average CPGAS was 2.4 ± 0.3 (SEM): 104 patients (75 %) improved (CPGAS > 0) and 34 (25 %) did not (CPGAS ≤ 0). Sixty patients (43 %) were at least moderately improved (CPGAS score ≥4). Clinical improvement was seen in both diabetic and idiopathic patients with the CPGAS in diabetic patients (3.5 ± 0.3) higher in idiopathic patients (1.5 ± 0.5; p < 0.05). Symptoms significantly improving the most included nausea, loss of appetite, and early satiety. Vomiting improved in both diabetic and idiopathic patients although the diabetic subgroup experienced a significantly greater reduction in vomiting than the idiopathic subgroup.

CONCLUSIONS

In this cohort of patients with refractory gastroparesis, GES improved symptoms in 75 % of patients with 43 % being at least moderately improved. Response in diabetics was better than in nondiabetic patients. Nausea, loss of appetite, and early satiety responded the best.

Novel insights into the effects of diabetes on gastric motility

Recent data from the Diabetes Control and Complications Trial/Epidemiology of Diabetic Interventions and Complications cohort indicate that the disease burden of gastroparesis in diabetes remains high, consistent with the outcome of cross-sectional studies in type 1 and 2 diabetes. An improved understanding of the pathogenesis of diabetic gastroparesis at the cellular level has emerged in the last decade, particularly as a result of initiatives such as the National Institute of Health funded Gastroparesis Clinical Research Consortium in the US. Management of diabetic gastroparesis involves dietary and psychological support, attention to glycaemic control, and the use of prokinetic agents. Given that the relationship between upper gastrointestinal symptoms and the rate of gastric emptying is weak, therapies targeted specifically at symptoms, such as nausea or pain, are important. The relationship between gastric emptying and postprandial glycaemia is complex and inter-dependent. Short-acting glucagon-like peptide-1 agonists, that slow gastric emptying, can be used to reduce postprandial glycaemic excursions and, in combination with basal insulin, result in substantial reductions in glycated haemoglobin in type 2 patients.

Current and Emerging Medical Therapies for Gastroparesis

OPINION STATEMENT

Gastroparesis likely involves various pathophysiological disorders and is increasingly prevalent as complications of surgeries, medications, and chronic diabetes. Key to diagnosis is evidence of delayed gastric emptying, generally based on standardized scintigraphy, and ruling out distal obstruction or other dysmotilities. Initial medical management includes reviewing potentially exacerbating medications and ruling out other reversible causes, achieving tighter glucose control in diabetics, and implementing dietary and lifestyle changes. While current available medications are limited, symptomatic control is aimed at improving gastric emptying, alleviating nausea and vomiting, and treating associated abdominal pain. Other potential therapies are aimed at reducing acid production, improving gastric accommodation or pyloric dysfunction, and treating bacterial overgrowth. Future studies should be aimed toward identification of subpopulations of gastroparetics who are better responders to the various medications based on differences in underlying pathophysiology and adopting standardized study end point measures that may allow for comparisons across trials. This chapter will review current treatment options, upcoming promising medications, and some of the hurdles in advancing the field forward.

Neuroenteric Stimulation for Gastroparesis

OPINION STATEMENT

Gastroparesis (GP) is a syndrome characterized by delayed gastric emptying in association with symptoms of epigastric pain, nausea, and vomiting in the absence of mechanical obstruction. The prevalence of gastroparesis has been estimated at 24 per 100,000, with women more commonly affected than men. Diabetes appears to be the underlying cause in approximately 25 % of patients, while connective tissue disorders, autoimmune disorders, prior gastric surgery, ischemia, and medications make up a smaller percentage of the remaining identifiable causes. However, the largest group of GP patients falls into the idiopathic category (~50 %); many of these patients likely develop GP as a result of a prior viral infection. Symptoms of gastroparesis develop due to a number of different pathophysiologic processes, including disorders of fundic accommodation, antroduodenal dyscoordination, a weak antral pump, gastric dysrhythmias, abnormal duodenal feedback, and enhanced visceral sensation. Once the diagnosis of GP is made, the clinician has a number of different treatment options. For patients with mild to moderate symptoms, dietary modifications in conjunction with or without prokinetics and antiemetics are often all that is required. However, many patients with severe symptoms who fail to respond to standard therapy may benefit from neuroenteric stimulation (gastric electrical stimulation). This monograph will review the role of the neuroenteric stimulator therapy for gastroparesis, discuss possible mechanisms of action of neuroenteric stimulation, review data from recently published studies on its efficacy, and discuss patient selection and adverse events.

Temporary Endoscopic Stimulation in Gastroparesis-like Syndrome

Background/Aims

Gastroparesis-like syndrome (GLS) is defined as gastroparesis-like symptoms with normal gastric scintigraphy. While the efficacy of gastric electrical stimulation (GES) in gastroparesis is well known, the utility of GES in GLS is largely unknown. Our aim was to clarify the role of GES in GLS. We implanted consecutive patients with symptoms of gastroparesis with temporary gastric electrical stimulation and observed changes in gastric scintigraphy and total symptom score.

Methods

Five hundred and fifty-one patients suffering from symptoms of gastroparesis (nausea, vomiting, bloating/distension, anorexia/early satiety, and abdominal pain) with negative endoscopy underwent gastric scintigraphy with analysis of 1) solid radio-nuclide gastric emptying at 1, 2, and 4 hours (% remaining); 2) area under the gastric emptying curve (AUC) at 1, 2, and 4 hours; and 3) total gastric emptying test (GET) (the sum of 1, 2, and 4 hour values). Patients were stratified into: delayed gastric emptying, normal gastric emptying, and rapid gastric emptying (Appendix). Of the 551 patients in the larger cohort, 379 had implantation of temporary gastric electrical stimulation (tGES). Gastrointestinal symptoms and gastric emptying were com -pared pre and post tGES implantation.

Results

After tGES, 2 hour gastric retention decreased (P < 0.01) for the delayed patients, and increased (P < 0.001) for normal and rapid patients. These changes were accompanied by improvements (P < 0.001) in vomiting, nausea, and total symptom scores in all 3 subgroups.

Conclusions

Gastric electrical stimulation may be an effective therapy for treating the symptoms of gastroparesis with normal gastric emptying. Further exploration of endoscopic electrical stimulation as a treatment for gastroparesis-like symptoms with non-delayed gastric emptying is needed.

Gastric Electrical Stimulation with the Enterra System: A Systematic Review

Background. Gastric electrical stimulation (GES) is a surgically implanted treatment option for refractory gastroparesis. Aim. To systematically appraise the current evidence for the use of gastric electrical stimulation and suggest a method of standardisation of assessment and follow-up in these patients. Methods. A systematic review of PubMed, Web of Science, DISCOVER, and Cochrane Library was conducted using the keywords including gastric electrical stimulation, gastroparesis, nausea, and vomiting and neuromodulation, stomach, central nervous system, gastric pacing, electrical stimulation, and gastrointestinal. Results. 1139 potentially relevant articles were identified, of which 21 met the inclusion criteria and were included. The quality of studies was variable. There was a variation in outcome measures and follow-up methodology. Included studies suggested significant reductions in symptom severity reporting over the study period, but improvements in gastric emptying time were variable and rarely correlated with symptom improvement. Conclusion. The evidence in support of gastric electrical stimulation is limited and heterogeneous in quality. While current evidence has shown a degree of efficacy in these patients, high-quality, large clinical trials are needed to establish the efficacy of this therapy and to identify the patients for whom this therapy is inappropriate. A consensus view on essential preoperative assessment and postoperative measurement is needed.

Novel surgical options for gastroesophageal reflux disease

There are limited options to patients with gastroesophageal reflux disease (GERD) who are not satisfied with acid suppression therapy. Fundoplication, the standard surgical procedure for GERD, is effective but is associated with adverse side effects and has thus been performed less frequently, creating a need for alternative surgical interventions that are effective, yet less invasive and reversible. Lately, two such interventions were developed: the magnetic sphincter augmentation and electrical stimulation of the lower esophageal sphincter. Human studies describing safety and efficacy over a follow-up period of a number of years have been published, documenting efficacy and safety of these interventions. Future studies should clarify the role of these procedures in the spectrum of GERD therapy.

Surgical approaches to treatment of gastroparesis: gastric electrical stimulation, pyloroplasty, total gastrectomy and enteral feeding tubes

Gastric electrical stimulation (GES) is neurostimulation; its mechanism of action is affecting central control of nausea and vomiting and enhancing vagal function. GES is a powerful antiemetic available for patients with refractory symptoms of nausea and vomiting from gastroparesis of idiopathic and diabetic causes. GES is not indicated as a way of reducing abdominal pain in gastroparetic patients. The need for introducing a jejunal feeding tube means intensive medical therapies are failing, and is an indication for the implantation of the GES system, which should always be accompanied by a pyloroplasty to guarantee accelerated gastric emptying.

Epidemiology and natural history of gastroparesis

Gastroparesis is characterized by delayed gastric emptying and symptoms thereof in the absence of gastric outlet obstruction. Most studies on the epidemiology of gastroparesis have been conducted in selected case series rather than in the population at large. In the only community-based study of gastroparesis in diabetes mellitus (DM), the average cumulative incidence of symptoms and delayed gastric emptying over 10 years was higher in type 1 DM (5%) than in type 2 DM (1%) and controls (1%). In the United States, the incidence of hospitalizations related to gastroparesis increased substantially between 1995 and 2004, and particularly after 2000.

Gastric emptying and glycaemia in health and diabetes mellitus

The rate of gastric emptying is a critical determinant of postprandial glycaemia and, accordingly, is fundamental to maintaining blood glucose homeostasis. Disordered gastric emptying occurs frequently in patients with longstanding type 1 diabetes mellitus and type 2 diabetes mellitus (T2DM). A complex bidirectional relationship exists between gastric emptying and glycaemia--gastric emptying accounts for ∼35% of the variance in peak postprandial blood glucose concentrations in healthy individuals and in patients with diabetes mellitus, and the rate of emptying is itself modulated by acute changes in glycaemia. Clinical implementation of incretin-based therapies for the management of T2DM, which diminish postprandial glycaemia, in part by slowing gastric emptying, is widespread. Other therapies for patients with T2DM, which specifically target gastric emptying include pramlintide and dietary-based treatment approaches. A weak association exists between upper gastrointestinal symptoms and the rate of gastric emptying. In patients with severe diabetic gastroparesis, pathological changes are highly variable and are characterized by loss of interstitial cells of Cajal and an immune infiltrate. Management options for patients with symptomatic gastroparesis remain limited in their efficacy, which probably reflects the heterogeneous nature of the underlying pathophysiology.

Evaluation and management of patients with symptoms after anti-reflux surgery

Over the past two decades, there has been an increase in the number of anti-reflux operations being performed. This is mostly due to the use of laparoscopic techniques, the increasing prevalence of gastroesophageal reflux disease (GERD) in the population, and the increasing unwillingness of patients to take acid suppressive medications for life. Laparoscopic fundoplication is now widely available in both academic and community hospitals, has a limited length of stay and postoperative recovery time, and is associated with excellent outcomes in carefully selected patients. Although the operation has low mortality and postoperative morbidity, it is associated with late postoperative complications, such as gas bloat syndrome, dysphagia, diarrhea, and recurrent GERD symptoms. This review summarizes the diagnostic evaluation and appropriate management of such postoperative complications. If a reoperation is needed, it should be performed by experienced foregut surgeons.

Follow-up after gastric electrical stimulation for gastroparesis

BACKGROUND

Gastric electrical stimulation (GES) is used to treat medically refractory gastroparesis. However, there are few large series with outcomes beyond 12 months. This study reports surgical outcomes of GES for patients up to 8 years receiving treatment from a single institution.

STUDY DESIGN

A prospective database was reviewed from 2003 to 2013 for patients undergoing GES. Baseline patient characteristics were recorded, including age, sex, cause of gastroparesis, gastric emptying, and Hgb A1C. Outcomes variables included nutrition supplementation, additional operations, 30-day morbidity, and mortality. Pre- and postoperative pain and function scores are analyzed over time using generalized estimating equations. Patient outcomes in terms of reoperation rates and types of operations are also reviewed.

RESULTS

Seventy-nine patients underwent GES with a mean ± SD age of 43 ± 11 years and a BMI of 27 ± 8 kg/m(2). Symptom scores were available for 60 patients: 60 patients at baseline, 52 patients at 1 year, 14 patients during years 2 to 3, and 18 patients during years 4 to 8. Symptom scores decreased considerably in all categories. At 1-year follow-up, 44% and 31% of patients had at least a 25% reduction in symptom distress for functional and pain symptoms, respectively. Preoperatively, 9 patients required nutrition supplementation. After implantation, 34 (43%) patients underwent additional operations, with a mean of 2.15 operations per patient. Generator-related causes were the most common indication for reoperation, including battery exchanges and relocation. Other operations included 8 gastrectomies and 7 median arcuate ligament releases. Postoperatively, 4 patients required supplemental nutrition. There were no 30-day mortalities, but 11 patients died during the study period.

CONCLUSIONS

Gastric electrical stimulation was significantly associated with reductions in both functional and pain-related symptoms of gastroparesis. Patients who undergo GES have a high likelihood of additional surgery.

Treatment of refractory diabetic gastroparesis: Western medicine and traditional Chinese medicine therapies

Refractory diabetic gastroparesis (DGP), a disorder that occurs in both type 1 and type 2 diabetics, is associated with severe symptoms, such as nausea and vomiting, and results in an economic burden on the health care system. In this article, the basic characteristics of refractory DGP are reviewed, followed by a discussion of therapeutic modalities, which encompasses the definitions and clinical manifestations, pathogenesis, diagnosis, and therapeutic efficacy evaluation of refractory DGP. The diagnostic standards assumed in this study are those set forth in the published literature due to the absence of recognized diagnosis criteria that have been assessed by an international organization. The therapeutic modalities for refractory DGP are as follows: drug therapy, nutritional support, gastric electrical stimulation, pyloric botulinum toxin injection, endoscopic or surgical therapy, and traditional Chinese treatment. The therapeutic modalities may be used alone or in combination. The use of traditional Chinese treatments is prevalent in China. The effectiveness of these therapies appears to be supported by preliminary evidence and clinical experience, although the mechanisms that underlie these effects will require further research. The purpose of this article is to explore the potential of combined Western and traditional Chinese medicine treatment methods for improved patient outcomes in refractory DGP.

Gastric electrical stimulation for treatment of clinically severe gastroparesis

BACKGROUND

Severe, drug-resistant gastroparesis is a debilitating condition. Several, but not all, patients can get significant relief from nausea and vomiting by gastric electrical stimulation (GES). A trial of temporary, endoscopically delivered GES may be of predictive value to select patients for laparoscopic-implantation of a permanent GES device.

MATERIALS AND METHODS

We conducted a clinical audit of consecutive gastroparesis patients, who had been selected for GES, from May 2008 to January 2012. Delayed gastric emptying was diagnosed by scintigraphy of ≥50% global improvement in symptom-severity and well-being was a good response.

RESULTS

There were 71 patients (51 women, 72%) with a median age of 42 years (range: 14-69). The aetiology of gastroparesis was idiopathic (43 patients, 61%), diabetes (15, 21%), or post-surgical (anti-reflux surgery, 6 patients; Roux-en-Y gastric bypass, 3; subtotal gastrectomy, 1; cardiomyotomy, 1; other gastric surgery, 2) (18%). At presentation, oral nutrition was supplemented by naso-jejunal tube feeding in 7 patients, surgical jejunostomy in 8, or parenterally in 1 (total 16 patients; 22%). Previous intervention included endoscopic injection of botulinum toxin (botox) into the pylorus in 16 patients (22%), pyloroplasty in 2, distal gastrectomy in 1, and gastrojejunostomy in 1. It was decided to directly proceed with permanent GES in 4 patients. Of the remaining, 51 patients have currently completed a trial of temporary stimulation and 39 (77%) had a good response and were selected for permanent GES, which has been completed in 35 patients. Outcome data are currently available for 31 patients (idiopathic, 21 patients; diabetes, 3; post-surgical, 7) with a median follow-up period of 10 months (1-28); 22 patients (71%) had a good response to permanent GES, these included 14 (68%) with idiopathic, 5 (71%) with post-surgical, and remaining 3 with diabetic gastroparesis.

CONCLUSIONS

Overall, 71% of well-selected patients with intractable gastroparesis had good response to permanent GES at follow-up of up to 2 years.

Gastric electrical stimulation with Enterra therapy improves symptoms of idiopathic gastroparesis

BACKGROUND

Gastric electrical stimulation (GES) is a therapeutic option for intractable symptoms of gastroparesis (GP). Idiopathic GP (ID-GP) represents a subset of GP.

AIMS

A prospective, multicenter, double-blinded, randomized, crossover study to evaluate the safety and efficacy of Enterra GES in the treatment of chronic vomiting in ID-GP.

METHODS

Thirty-two ID-GP subjects (mean age 39; 81% F, mean 7.7 years of GP) were implanted with GES. The stimulator was turned ON for 1½ months followed by double-blind randomization to consecutive 3-month crossover periods with the device either ON or OFF. ON stimulation was followed in unblinded fashion for another 4.5 months. Twenty-five subjects completed the crossover phase and 21 finished 1 year of follow-up.

KEY RESULTS

During the unblinded ON period, there was a reduction in weekly vomiting frequency (WVF) from baseline (61.2%, P < 0.001). There was a non-significant reduction in WVF between ON vs OFF periods (the primary outcome) with median reduction of 17% (P > 0.10). Seventy-five percent of patients preferred the ON vs OFF period (P = 0.021). At 1 year, WVF remained decreased (median reduction = 87%, P < 0.001), accompanied by improvements in GP symptoms, gastric emptying and days of hospitalization (P < 0.05).

CONCLUSIONS & INFERENCES

(i) In this prospective study of Enterra GES for ID-GP, there was a reduction in vomiting during the initial ON period; (ii) The double-blind 3-month periods showed a non-significant reduction in vomiting in the ON vs OFF period, the primary outcome variable; (iii) At 12 months with ON stimulation, there was a sustained decrease in vomiting and days of hospitalizations.

Evaluation and treatment of gastric stimulator failure in patients with gastroparesis

OBJECTIVE

This study evaluates treatment of gastroparesis patients refractory to gastric electrical stimulation (GES) therapy with surgical replacement of the entire GES system.

SUMMARY BACKGROUND DATA

Some patients who have symptomatic improvement with GES later develop recurrent symptoms. Some patients improve by simply altering pulse parameter settings. Others continue to have symptoms with maximized pulse parameters. For these patients, we have shown that surgical implantation of a new device and leads at a different gastric location will improve symptoms of gastroparesis.

METHODS

This study evaluates 15 patients with recurrent symptoms after initial GES therapy who subsequently received a second GES system. Positive response to GES replacement therapy is evaluated by symptoms scores for vomiting, nausea, epigastric pain, early satiety, and bloating using a modified Likert score system, 0 to 4.

RESULTS

Total symptom scores improved for 12 of 15 patients with GES replacement surgery. Total score for the replacement group decreased from 17.3 ± 1.6 to 13.6 ± 3.7 with a difference of 3.6 (P value = .017). This score is compared with that of the control group with a preoperative symptom score of 15.8 ± 3.6 and postoperative score of 12.3 ± 3.5 with a difference of 3.5 (P value = .011). The control group showed a 20.3% decrease in mean total symptoms score, whereas the study group showed a 22.5% decrease in mean with an absolute reduction of 2.2.

CONCLUSION

Reimplantation of a GES at a new gastric location should be considered a viable option for patients who have initially failed GES therapy for gastroparesis.

Improvement of quality of life and symptoms after gastric electrical stimulation in children with functional dyspepsia

BACKGROUND

Our objective is to evaluate the effect of gastric electrical stimulation (GES) on symptoms and quality of life for pediatric patients with functional dyspepsia (FD).

METHODS

Twenty-four patients (16 female, median 15 years) were treated with GES for FD after a median of 24 months of symptoms (3 months-14 years). At baseline, 46% required tube feeds and 25% parenteral nutrition. Sixty percent had gastroparesis. The PedsQL GI Module (PedsQL) was completed for 18/24 both pre-/post-GES after a median of 8 months. Patients also completed the Symptom Monitor Worksheet (SMW) pre-/post-GES after a median of 6 months. Pre-/post-GES global health was also assessed.

KEY RESULTS

Significant improvements were seen in multiple areas of the PedsQL, including stomach pain/upset, food/drink limits, heartburn/reflux, gas/bloating, patient worry, medication tolerance, and constipation (P < 0.05). A decrease was found in combined symptom severity/frequency based on SMW (P < 0.01). Improvements were made in all categories, including vomiting, nausea, early satiety, bloating, fullness, epigastric pain, and burning (P < 0.01). Improvements in PedsQL/SMW scores remained when analysis was limited to normal or delayed gastric emptying (P < 0.05, P < 0.05). Thirteen percent needed tube feeds and 13% parenteral nutrition after GES. Sixty-five percent reported that their health was much improved after GES vs 15% the same or worse. Five patients experienced complications, primarily mild abdominal discomfort.

CONCLUSIONS & INFERENCES

In the largest series to date of pediatric patients who have undergone GES for FD, we found significant improvements in upper gastrointestinal symptoms, quality of life, and perception of global health. Patients were less dependent on tube feeding or parenteral nutrition.

Gastrointestinal complications of diabetes mellitus

Diabetes mellitus affects virtually every organ system in the body and the degree of organ involvement depends on the duration and severity of the disease, and other co-morbidities. Gastrointestinal (GI) involvement can present with esophageal dysmotility, gastro-esophageal reflux disease (GERD), gastroparesis, enteropathy, non alcoholic fatty liver disease (NAFLD) and glycogenic hepatopathy. Severity of GERD is inversely related to glycemic control and management is with prokinetics and proton pump inhibitors. Diabetic gastroparesis manifests as early satiety, bloating, vomiting, abdominal pain and erratic glycemic control. Gastric emptying scintigraphy is considered the gold standard test for diagnosis. Management includes dietary modifications, maintaining euglycemia, prokinetics, endoscopic and surgical treatments. Diabetic enteropathy is also common and management involves glycemic control and symptomatic measures. NAFLD is considered a hepatic manifestation of metabolic syndrome and treatment is mainly lifestyle measures, with diabetes and dyslipidemia management when coexistent. Glycogenic hepatopathy is a manifestation of poorly controlled type 1 diabetes and is managed by prompt insulin treatment. Though GI complications of diabetes are relatively common, awareness about its manifestations and treatment options are low among physicians. Optimal management of GI complications is important for appropriate metabolic control of diabetes and improvement in quality of life of the patient. This review is an update on the GI complications of diabetes, their pathophysiology, diagnostic evaluation and management.

Factors influencing admission and outcomes in gastroparesis

BACKGROUND

Current data suggest that gastroparesis is associated with an increased mortality, with reported rates ranging from 4% to nearly 40%. Considering this variability, the goal of this study was to determine mortality rates and risk factors for adverse outcomes in gastroparesis.

METHODS

Using the diagnosis code for gastroparesis, admission rates, duration of hospitalizations, discharge status, and inpatient mortality were determined for emergency department encounters and admissions compiled in the Nationwide Emergency Department Sample and Nationwide Inpatient Sample of the Agency for Healthcare Research and Quality. Comorbid conditions, procedural evaluations, age cohort, and gender distribution were examined as potential risk factors.

KEY RESULTS

More than 50% of the emergency encounters for gastroparesis resulted in admission with age, cardiovascular, renal, and infectious disorders, but not diabetes mellitus being associated with higher admission rates. Inpatient mortality was 1.2 ± 0.1%, was not negatively affected by diabetes mellitus as comorbidity, and increased with coexisting infections and with more aggressive therapy. Discharge status was similarly affected by comorbidities, treatment complications, and more aggressive therapy.

CONCLUSIONS & INFERENCES

These results demonstrate that gastroparesis does not come with a high mortality risk, with most deaths being due to comorbid conditions. Although gastrostomies and/or nutritional support were used in only a minority of admissions, the associated increase in morbidity and mortality highlights the need to carefully select the right candidates for such interventions and to discuss the common occurrence of adverse outcomes with patients.

Laparoscopic gastric electrical stimulation for medically refractory diabetic and idiopathic gastroparesis

BACKGROUND

Gastric electrical stimulator (GES) implantation is effective in certain patients with gastroparesis; however, laparotomy is often employed for placement. The aim of this study is to review outcomes of patients who underwent laparoscopic GES therapy for diabetic and idiopathic gastroparesis at a large referral center.

METHODS

Patients who underwent GES (Enterra Therapy System; Medtronic, Minneapolis, MN) implantation with subsequent interrogation and programming between March 2001 and November 2011 were analyzed.

RESULTS

A total of 113 patients underwent GES placement or revision during the study period. One hundred eleven patients underwent primary GES at our institution, while two patients underwent GES generator revision at our institution. Primary operations were completed laparoscopically in 110 of 111 cases, with one conversion to laparotomy due to severe adhesions. At a mean follow-up of 27 months (1-113), symptom improvement was achieved in 91 patients (80 %) and was similar for both the diabetic and idiopathic subgroups. Need for supplemental nutrition (enteral and/or parental) decreased in both groups.

CONCLUSIONS

GES placement is feasible using a laparoscopic approach. Medical refractory gastroparesis in the diabetic and idiopathic groups had significant symptom improvement with no difference between the two groups. Need for supplemental nutrition is decreased following GES.

Gastric electrical stimulation increases the discomfort threshold to gastric distension

INTRODUCTION

Gastric electrical stimulation (GES) is now considered as a new therapeutic alternative for patients with medically refractory vomiting and/or nausea, although its mechanisms of action remain poorly understood.

METHODS AND PATIENTS

Gastric discomfort threshold, measured as the gastric maximal tolerable volume (MTV) to distension, was examined before and after GES, in nine patients implanted for chronic and severe nausea and vomiting.

RESULTS

GES increased gastric MTV from 522 ± 64 ml at baseline to 628 ± 60 ml 6 months after the start of GES (P=0.03), whereas gastric emptying remained unchanged. The increase in MTV was correlated with symptoms and quality of life at 6 months, whereas gastric emptying was not. Finally, MTV varied in a similar manner at 6 months in patients with delayed and normal gastric emptying measured before implantation.

CONCLUSION

Taken together, these data indicate that modification of gastric sensation to distension, rather than gastric emptying, is associated with symptoms' outcome during GES.

The addition of pyloroplasty as a new surgical approach to enhance effectiveness of gastric electrical stimulation therapy in patients with gastroparesis

BACKGROUND

Improvement of gastroparesis (GP) symptoms has been documented in patients treated with gastric electrical stimulation (GES), but acceleration of gastric emptying (GET) is unpredictable. The aim of our study was to evaluate the advantage of adding surgical pyloroplasty (PP) to GES for improvement of GET and control of symptoms in diabetes mellitus (DM), idiopathic (ID), and postvagotomy (P-V) GP.

METHODS

A total of 49 (17 - DM, 9 - ID, 23 - P-V) consecutive GP patients: 38 female; mean age 42 (21-73 years); mean weight 158 lbs (102-245), underwent GES implantation, and 26 (53%) additionally received PP. Total Symptoms Score, 4-h GET, adverse events (AEs), and days of hospitalizations were captured at baseline and at the last visit.

KEY RESULTS

The mean follow-up was 7 months. Total Symptoms Score in patients who received Enterra and PP or GES alone significantly improved compared to their baseline scores (P < 0.001). GET improved by 64% at 4 h (P < 0.001) in patients with Enterra and PP, compared to 7% observed after GES therapy alone (ns). The most impressive acceleration of GET was seen in the P-V group, who received both therapies (P = 0.004) and 8 (60%) of them normalized GET. No AEs accompanied the addition of PP to the Enterra surgery.

CONCLUSIONS & INFERENCES

(i) In drug-refractory GP the addition of PP to GES substantially accelerated GET; (ii) The GET response in P-V group was the most impressive; (iii) Significant symptom reductions were achieved by both procedures; and (iv) PP added to GES may sustain better long-term symptoms control particularly in the P-V setting.

Efficacy of permanent gastric electrical stimulation for the treatment of gastroparesis and functional dyspepsia in children and adolescents

PURPOSE

Permanent gastric electrical stimulation (GES) has been performed in adults as a treatment for gastroparesis and refractory nausea and vomiting in patients who have failed medical therapy. We assessed the feasibility and clinical outcomes of permanent GES in children.

METHODS

Permanent GES was performed in 16 children (10 females/6 males), median age 15 years (range 4-19 years). All patients had chronic nausea and vomiting refractory to medical therapy and met ROME III criteria for functional dyspepsia. Symptoms, route for nutrition, and satisfaction with procedure were recorded before and after permanent GES. Statistical analysis was performed using paired Student's t test.

RESULTS

After permanent GES, there was significant improvement in severity of vomiting (p=0.0001), frequency of vomiting (p=0.0003), frequency of nausea (p<0.0001), and severity of nausea (p<0.0001). At the time of follow-up, 13/16 were on oral feeds exclusively, two patients on oral plus G-tube feedings, and one patient on oral plus G-tube plus intermittent TPN.

CONCLUSIONS

1). Permanent GES improved health in children with functional dyspepsia and gastroparesis who fail medical therapy. 2). No serious adverse effects of permanent GES were noted. 3). Long-term efficacy and safety of GES therapy in children need to be established.

Clinical guideline: management of gastroparesis

This guideline presents recommendations for the evaluation and management of patients with gastroparesis. Gastroparesis is identified in clinical practice through the recognition of the clinical symptoms and documentation of delayed gastric emptying. Symptoms from gastroparesis include nausea, vomiting, early satiety, postprandial fullness, bloating, and upper abdominal pain. Management of gastroparesis should include assessment and correction of nutritional state, relief of symptoms, improvement of gastric emptying and, in diabetics, glycemic control. Patient nutritional state should be managed by oral dietary modifications. If oral intake is not adequate, then enteral nutrition via jejunostomy tube needs to be considered. Parenteral nutrition is rarely required when hydration and nutritional state cannot be maintained. Medical treatment entails use of prokinetic and antiemetic therapies. Current approved treatment options, including metoclopramide and gastric electrical stimulation (GES, approved on a humanitarian device exemption), do not adequately address clinical need. Antiemetics have not been specifically tested in gastroparesis, but they may relieve nausea and vomiting. Other medications aimed at symptom relief include unapproved medications or off-label indications, and include domperidone, erythromycin (primarily over a short term), and centrally acting antidepressants used as symptom modulators. GES may relieve symptoms, including weekly vomiting frequency, and the need for nutritional supplementation, based on open-label studies. Second-line approaches include venting gastrostomy or feeding jejunostomy; intrapyloric botulinum toxin injection was not effective in randomized controlled trials. Most of these treatments are based on open-label treatment trials and small numbers. Partial gastrectomy and pyloroplasty should be used rarely, only in carefully selected patients. Attention should be given to the development of new effective therapies for symptomatic control.

Long-term effects of gastric stimulation on gastric electrical physiology

INTRODUCTION

This study evaluates the modeling of gastric electrophysiology tracings during long-term gastric electrical stimulation for gastroparesis. We hypothesized that serosal electrogastrogram may change over time representing gastric remodeling from gastric stimulation.

PATIENTS

Sixty-five patients with gastroparesis underwent placement of gastric stimulator for refractory symptoms. Mean age at initial stimulator placement was 44 years (range, 8-76), current mean age was 49, and the majority of the subjects were female (n = 51, 78 %). Only a minority had diabetes-induced gastroparesis (n = 16, 25 %); the remainder were either idiopathic or postsurgical.

METHODS

At the time of stimulator placement, electrogastrogram was performed after the gastric leads were placed but before stimulation was begun. Patients underwent continuous stimulation until pacer batteries depleted. At the time of replacement, before the new pacemaker was attached, electrogastrogram was again performed.

RESULTS

After a mean of 3.9 years of stimulation therapy, the mean of baseline frequency before stimulation therapy was 5.06 cycles/min and declined to 3.66 after replacement (p = 0.0000002). The mean amplitude was 0.33 mV before stimulation therapy and decreased to 0.31 mV (p = 0.73). The frequency/amplitude ratio was 38.4 before stimulation therapy and decreased to 21.9 (p = 0.001).

CONCLUSION

Long-term gastric electrical stimulation causes improvement in basal unstimulated gastric frequency to near normal.

Gastroparesis on the rise: incidence vs awareness?

BACKGROUND

Recent reports provide a conflicting picture with a stable prevalence of gastroparesis (GP) in a population-based study, but a more than doubling in hospitalizations for gastroparesis within the last 10 years. We hypothesized that this apparent discrepancy is due to changes in disease recognition and coding rather than prevalence.

METHODS

Using data from the Nationwide Inpatient Sample, Healthcare cost and utilization project, Agency for Healthcare Research and Quality, we examined time trends of resource utilization for GP and related disorders.

KEY RESULTS

Between 1994 and 2009, annual hospitalizations for gastroparesis as primary diagnosis increased more than 18-fold from 918 to 16,736. In the same time frame, hospitalizations for not otherwise specified functional disorders of the stomach decreased by nearly 50% from 13,430 to 6480 per year.

CONCLUSIONS & INFERENCES

Although hospitalizations rates and emergency encounters for gastroparesis have increased dramatically within the last 2 decades, there was a concomitant decrease in resource utilization for other functional disorders of the stomach, suggesting that increased awareness contributed to this trend, which represents a shift in diagnoses rather than a true difference in the incidence and/or prevalence of these illnesses.

Gastric electrical stimulation decreases gastric distension-induced central nociception response through direct action on primary afferents

Background & Aims

Gastric electrical stimulation (GES) is an effective therapy to treat patients with chronic dyspepsia refractory to medical management. However, its mechanisms of action remain poorly understood.

Methods

Gastric pain was induced by performing gastric distension (GD) in anesthetized rats. Pain response was monitored by measuring the pseudo-affective reflex (e.g., blood pressure variation), while neuronal activation was determined using c-fos immunochemistry in the central nervous system. Involvement of primary afferents was assessed by measuring phosphorylation of ERK1/2 in dorsal root ganglia.

Results

GES decreased blood pressure variation induced by GD, and prevented GD-induced neuronal activation in the dorsal horn of the spinal cord (T9–T10), the nucleus of the solitary tract and in CRF neurons of the hypothalamic paraventricular nucleus. This effect remained unaltered within the spinal cord when sectioning the medulla at the T5 level. Furthermore, GES prevented GD-induced phosphorylation of ERK1/2 in dorsal root ganglia.

Conclusions

GES decreases GD-induced pain and/or discomfort likely through a direct modulation of gastric spinal afferents reducing central processing of visceral nociception.

Gastroparesis

PURPOSE OF REVIEW

Gastroparesis is a common disorder that produces symptoms of gastric retention in the absence of physical obstruction. Extensive research into the clinical features, pathophysiology, diagnostic evaluation, and therapy of gastroparesis in the past several years has offered insight into the condition. This review provides updated information on gastroparesis focusing on new findings from the past few years.

RECENT FINDINGS

Large database studies have characterized clinical profiles in idiopathic and diabetic gastroparesis and are defining roles of gastric and extragastric factors in symptom genesis. Dietary deficiencies in gastroparesis have been clarified. Histologic study of full thickness gastric tissue in severe gastroparesis shows heterogeneous enteric neuronal, smooth muscle, interstitial cell, and inflammatory abnormalities. Advances in gastric emptying testing include wireless motility capsules and nonradioactive breath tests. The importance of glycemic control in diabetic gastroparesis is a focus of current investigation. Novel therapies include new prokinetics (ghrelin agonists), increased focus on antiemetic agents including antidepressants, and next generation gastric stimulators. Studies are being initiated to delineate the natural history of gastroparesis.

SUMMARY

Much has been learned recently on the causes, clinical presentations, and management of gastroparesis. Current ongoing investigation provides promise for further gains in the years ahead.

Electrical stimulation therapy of the lower esophageal sphincter is successful in treating GERD: final results of open-label prospective trial

BACKGROUND

Electrical stimulation of the lower esophageal sphincter (LES) improves LES pressure without interfering with LES relaxation. The aim of this open-label pilot trial was to evaluate the safety and efficacy of long-term LES stimulation using a permanently implanted LES stimulator in patients with gastroesophageal reflux disease (GERD).

METHODS

GERD patients who were at least partially responsive to proton pump inhibitors (PPI) with abnormal esophageal pH, hiatal hernia ≤ 3 cm, and esophagitis ≤ LA grade C were included. Bipolar stitch electrodes were placed in the LES and an IPG was placed in a subcutaneous pocket. Electrical stimulation was delivered at 20 Hz, 215 μs, 3-8 mA in 30 min sessions. The number and timing of sessions was tailored to each patient's GERD profile. Patients were evaluated using GERD-HRQL, daily symptom and medication diaries, SF-12, esophageal pH, and high-resolution manometry.

RESULTS

24 patients (mean age = 53 years, SD = 12 years; 14 men) were implanted; 23 completed their 6-month evaluation. Median GERD-HRQL scores at 6 months was 2.0 (IQR = 0-5.5) and was significantly better than both baseline on-PPI [9.0 (range = 6.0-10.0); p < 0.001] and off-PPI [23 (21-25); p < 0.001] GERD-HRQL. Median% 24-h esophageal pH < 4.0 at baseline was 10.1 and improved to 5.1 at 6 months (p < 0.001). At their 6-month follow-up, 91 % (21/23) of the patients were off PPI and had significantly better median GERD-HRQL on LES stimulation compared to their on-PPI GERD-HRQL at baseline (9.0 vs. 2.0; p < 0.001). There were no unanticipated implantation- or stimulation-related adverse events or untoward sensation due to stimulation. There were no reports of treatment-related dysphagia, and manometric swallow was also unaffected.

CONCLUSIONS

Electrical stimulation of the LES is safe and effective for treating GERD. There is a significant and sustained improvement in GERD symptoms, esophageal pH, and reduction in PPI usage without any side effects with the therapy. Furthermore, the therapy can be optimized to address an individual patient's disease.

Electrical stimulation therapy of the lower esophageal sphincter is successful in treating GERD: final results of open-label prospective trial

BACKGROUND

Electrical stimulation of the lower esophageal sphincter (LES) improves LES pressure without interfering with LES relaxation. The aim of this open-label pilot trial was to evaluate the safety and efficacy of long-term LES stimulation using a permanently implanted LES stimulator in patients with gastroesophageal reflux disease (GERD).

METHODS

GERD patients who were at least partially responsive to proton pump inhibitors (PPI) with abnormal esophageal pH, hiatal hernia ≤ 3 cm, and esophagitis ≤ LA grade C were included. Bipolar stitch electrodes were placed in the LES and an IPG was placed in a subcutaneous pocket. Electrical stimulation was delivered at 20 Hz, 215 μs, 3-8 mA in 30 min sessions. The number and timing of sessions was tailored to each patient's GERD profile. Patients were evaluated using GERD-HRQL, daily symptom and medication diaries, SF-12, esophageal pH, and high-resolution manometry.

RESULTS

24 patients (mean age = 53 years, SD = 12 years; 14 men) were implanted; 23 completed their 6-month evaluation. Median GERD-HRQL scores at 6 months was 2.0 (IQR = 0-5.5) and was significantly better than both baseline on-PPI [9.0 (range = 6.0-10.0); p < 0.001] and off-PPI [23 (21-25); p < 0.001] GERD-HRQL. Median% 24-h esophageal pH < 4.0 at baseline was 10.1 and improved to 5.1 at 6 months (p < 0.001). At their 6-month follow-up, 91 % (21/23) of the patients were off PPI and had significantly better median GERD-HRQL on LES stimulation compared to their on-PPI GERD-HRQL at baseline (9.0 vs. 2.0; p < 0.001). There were no unanticipated implantation- or stimulation-related adverse events or untoward sensation due to stimulation. There were no reports of treatment-related dysphagia, and manometric swallow was also unaffected.

CONCLUSIONS

Electrical stimulation of the LES is safe and effective for treating GERD. There is a significant and sustained improvement in GERD symptoms, esophageal pH, and reduction in PPI usage without any side effects with the therapy. Furthermore, the therapy can be optimized to address an individual patient's disease.

Long term efficacy of gastric electrical stimulation in intractable nausea and vomiting

BACKGROUND

Although the efficacy of gastric electrical stimulation has been reported in short-term studies, there is a lack of data on the long-term improvement of nausea and vomiting by gastric electrical stimulation in patients with delayed or normal gastric emptying.

METHODS

Thirty-one patients were implanted at our centre for medically refractory severe and chronic nausea and/or vomiting. Patients were evaluated at baseline, 6 months then 5 years after implantation (mean follow-up 80±4 months) using a symptomatic and quality of life scores.

KEY RESULTS

Amongst the 31 patients, 4 were lost to follow-up, 6 explanted due to lack of improvement, and 1 patient died. Out of the 20 patients evaluated over 5 years, the quality of life score showed 27% improvement (p<0.01), including nausea (62%; p<0.01), vomiting (111%; p=0.03), satiety (158%; p<0.01), bloating (67%; p<0.01) and epigastric pain (43%; p=0.03). Over 5 years, 15/20 patients reported a 50% improvement with a global satisfaction rated at 64±6%. Therefore, 15/27 patients (56%) were improved by gastric electrical stimulation over 5 years in intention to treat. Improvement of nausea 6 months after implantation was predictive of 5-year success of gastric electrical stimulation (p=0.04). Finally, patients with delayed gastric emptying or with normal gastric emptying rate before surgery were similarly improved over 5 years (60% versus 50% respectively).

CONCLUSION

Gastric electrical stimulation is safe and effective in the long term in patients with medically refractory nausea and vomiting, with an efficacy over 50% beyond 5 years in intention to treat. Gastric emptying measured before implantation did not influence the response rate over 5 years.