Fundic balloon distension stimulates antral and duodenal motility in man

Gastric per-oral endoscopic myotomy: Current status and future directions

Gastroparesis, or symptomatic delayed gastric emptying in the absence of mechanical obstruction, is a challenging and increasingly identified syndrome. Medical options are limited and the only medication approved by the Food and Drug Administration for treatment of gastroparesis is metoclopramide, although other agents are frequently used off label. With this caveat, first-line treatments for gastroparesis include dietary modifications, antiemetics and promotility agents, although these therapies are limited by suboptimal efficacy and significant medication side effects. Treatment of patients that fail first-line treatments represents a significant therapeutic challenge. Recent advances in endoscopic techniques have led to the development of a promising novel endoscopic therapy for gastroparesis via endoscopic pyloromyotomy, also referred to as gastric per-oral endoscopic myotomy or per-oral endoscopic pyloromyotomy. The aim of this article is to review the technical aspects of the per-oral endoscopic myotomy procedure for the treatment of gastroparesis, provide an overview of the currently published literature, and outline potential next directions for the field.

Association between duration or etiology of gastroparesis and clinical response after gastric per-oral endoscopic pyloromyotomy

BACKGROUND AND AIMS

Gastric per-oral endoscopic pyloromyotomy (GPOEM) is a novel procedure with promising potential for the treatment of gastroparesis but with limited data regarding predictors of clinical response. This study aims to evaluate the safety and efficacy of the procedure and explore the impact of duration and etiology (diabetic vs nondiabetic) of gastroparesis on clinical outcome as measured by the Gastroparesis Cardinal Symptom Index (GCSI).

METHODS

A single-center retrospective longitudinal study at a tertiary care hospital was performed over an 18-month period. Forty patients with refractory gastroparesis (25 nondiabetic and 15 diabetic patients) were included.

RESULTS

GCSI significantly improved throughout the study period (F[2.176, 17.405] = 10.152, P = .001). The nausea/vomiting subscale showed sustained improvement through 18 months (F[2.213, 17.704] = 15.863, P < .00001). There was no significant improvement in bloating (F[2.099, 16.791] = 1.576, P = .236). Gastric scintigraphy retention was significantly reduced by 41.7% (t = -7.90; P < .00001). Multivariate linear regression modeling revealed a significant correlation between the duration of disease and a GCSI improvement at 12 months (P = .02), with a longer duration of disease associated with a poorer long-term response. The etiology of gastroparesis was not associated with clinical improvement (P = .16). Adverse events (7.5%) included 1 capnoperitoneum, 1 periprocedure chronic obstructive pulmonary disease exacerbation, and 1 mucosotomy closure site disruption.

CONCLUSIONS

GPOEM appears to be a safe and effective minimally invasive therapy for refractory gastroparesis, especially for patients with predominant nausea/vomiting and shorter duration of disease, regardless of the etiology. We propose the clinical criteria for undergoing GPOEM should be a GCSI of at least 2.0 and a gastric retention of greater than 20%.

Outcomes of per oral endoscopic pyloromyotomy in gastroparesis worldwide

Per oral endoscopic pyloromyotomy (POP), also known as gastric per-oral endoscopic myotomy (GPOEM), is a novel procedure with promising potential for the treatment of gastroparesis. As more data emerge and the procedure is becoming more recognized in clinical practice, its safety and efficacy need to be carefully evaluated. Appropriate patient selection for favorable clinical success prediction after GPOEM also needs additional research. This review aims to systemically summarize the existing data on clinical outcomes of POP. Symptomatologic responses to the procedure, its adverse effects, procedural techniques, and predictive factors of clinical success are also discussed.

Gastric Peroral Endoscopic Pyloromyotomy Reduces Symptoms, Increases Quality of Life, and Reduces Health Care Use For Patients With Gastroparesis

BACKGROUND & AIMS

Gastric peroral endoscopic pyloromyotomy (GPOEM) is becoming a promising treatment option for patients with refractory gastroparesis. We aimed to systematically assess the efficacy of GPOEM and its effects on health care use.

METHODS

We performed a retrospective study on 30 patients with refractory gastroparesis who underwent GPOEM from June 2015 through July 2017 at a tertiary center. We compared outcomes with those of 7 patients with refractory gastroparesis who did not undergo the procedure (controls). The primary outcomes were patient-reported reductions in symptoms, based on the gastroparesis cardinal symptom index (GCSI), and increases in 8 aspects of quality of life, based on Short Form 36 (SF-36) scores. Data were collected on the day of the procedure (baseline) and at 1 month, 6 months, 12 months, and 18 months afterward. Secondary outcomes included visits to the emergency department or hospitalization for gastroparesis-related symptoms.

RESULTS

GPOEM was technically successful in all patients and significantly reduced GCSI scores in repeated-measure analysis of variance (F_{2.044, 38.838} = 22.319; P < .0005). The mean score at baseline was 3.5 ± 0.6, at 1 month after GPOEM was 1.8 ± 1.0 (P < .0005), at 6 months after was 1.9 ± 1.2 (P < .0005), at 12 months after was 2.6 ± 1.5 (P < .026), and at 18 months after was 2.1 ± 1.3 (P < .016). GPOEM was associated with improved quality of life: 77.8%, 76.5%, and 70% of patients had significant increases in SF-36 scores, compared with baseline, at 1 month, 6 months, and 12 months after GPOEM, respectively (F_1.71,18.83 = 14.16; P < .0005). Compared with controls, patients who underwent GPOEM had significant reductions in GCSI, after we controlled for baseline score and duration of the disease (F_1,31 = 9.001; P = .005). Patients who received GPOEM had significant reductions in number of emergency department visits (from 2.2 ± 3.1 times/mo at baseline to 0.3 ± 0.8 times/mo; P = .003) and hospitalizations (from 1.7 ± 2 times/mo at baseline to 0.2 ± 0.4 times/mo; P = .0002).

CONCLUSIONS

In a retrospective study of patients who underwent GPOEM for refractory gastroparesis, we found the procedure significantly improved symptoms, increased quality of life, and reduced health care use related to gastroparesis.

Outcomes of Per Oral Endoscopic Pyloromyotomy in the United States

Per oral endoscopic pyloromyotomy (POP) has emerged as an endoscopic intervention for refractory gastroparesis. Early experience in the United States showed exciting clinical response rate, reduced gastroparesis symptoms, improved quality of life, and decreased gastric-emptying time during midterm follow-up up to 18 months. One recent study also showed that the number of patient emergency room visits and hospitalizations decreased significantly after POP. The procedure is technically feasible and safe. As more data become available, it is important to identify patients who would benefit most from this novel procedure.

Pyloric Therapies for Gastroparesis

OPINION STATEMENT

Gastroparesis is a syndrome that can be difficult to treat effectively and likely represents the common clinical presentation of multiple underlying mechanisms. One of these presumed mechanisms involves pyloric dysfunction, tied perhaps to spasm or fibrosis, manifesting as functional gastric outlet obstruction. Various diagnostic modalities have been used to better characterize this hypothesized abnormality, including most recently antroduodenal manometry and impedance planimetry. A variety of therapeutic interventions specific to the pylorus have also been proposed in the last several years, including intrapyloric injections of botulinum toxin, transpyloric stenting, surgical pyloroplasty, and endoscopic pyloromyotomy. The clinical application of these maneuvers has been mostly empiric thus far, but efforts are ongoing to identify the subset of patients whose physiology best positions them to benefit from such therapy. Early results for many of these interventions have been promising and will serve as the basis for larger and more systematic research frameworks moving forward.

Effect of liquid meals with different volumes on gastroesophageal reflux disease

BACKGROUND AND AIM

Patients with gastroesophageal reflux disease (GERD) are often advised to avoid large meals, based on their complaints of increased symptoms after eating too much, and epidemiological evidence of a link between high volume intake and the presence of GERD. However, the precise effects of meal volume on gastroesophageal reflux have not been well studied. We aimed to clarify the effect of meal volume on acid regurgitation and symptoms in patients with GERD.

METHODS

Fifteen patients (10 female, 5 male; mean 54 ± 10 years old) with GERD were studied twice each in random order, during 24 h ambulatory pH monitoring. On one day, they consumed a 600 mL liquid test meal three times (breakfast, lunch, and dinner), and on the other, they consumed a 300 mL test meal six times (breakfast, snack, lunch, snack, dinner, and snack). Gastric fundus and antral areas and antral contractions were measured by transabdominal ultrasound. Symptoms were recorded using questionnaires.

RESULTS

During the 600 mL regimen, there were more reflux episodes (17 ± 4 vs 10 ± 2, P = 0.03) and a greater total acid reflux time (12.5 ± 5.9% vs 5.5 ± 3.6%; P = 0.045) than the 300 mL regimen. Both the cross-sectional area of the gastric fundus (P = 0.024) and the number of antral contractions (P = 0.014) were greater for the 600 mL regimen.

CONCLUSIONS

Larger meals are associated with distension of the gastric fundus and an increase in gastroesophageal reflux when compared with smaller, more frequent meals.

Gastric sensitivity and reflexes: basic mechanisms underlying clinical problems

Both reflex and sensory mechanisms control the function of the stomach, and disturbances in these mechanisms may explain the pathophysiology of disorders of gastric function. The objective of this report is to perform a literature-based critical analysis of new, relevant or conflicting information on gastric sensitivity and reflexes, with particular emphasis on the comprehensive integration of basic and clinical research data. The stomach exerts both phasic and tonic muscular (contractile and relaxatory) activity. Gastric tone determines the capacity of the stomach and mediates both gastric accommodation to a meal as well as gastric emptying, by partial relaxation or progressive recontraction, respectively. Perception and reflex afferent pathways from the stomach are activated independently by specific stimuli, suggesting that the terminal nerve endings operate as specialized receptors. Particularly, perception appears to be related to stimulation of tension receptors, while the existence of volume receptors in the stomach is uncertain. Reliable techniques have been developed to measure gastric perception and reflexes both in experimental and clinical conditions, and have facilitated the identification of abnormal responses in patients with gastric disorders. Gastroparesis is characterised by impaired gastric tone and contractility, whereas patients with functional dyspepsia have impaired accommodation, associated with antral distention and increased gastric sensitivity. An integrated view of fragmented knowledge allows the design of pathophysiological models in an attempt to explain disorders of gastric function, and may facilitate the development of mechanistically orientated treatments.

Alterations of global gastrointestinal motility after sleeve gastrectomy: a prospective study

OBJECTIVES

To evaluate the role of sleeve gastrectomy (SG) in gastrointestinal motility.

BACKGROUND

SG is a widely used bariatric operation leading to weight loss and early improvement of patient's metabolic profile. Current data indicate faster postoperative gastric emptying, but detailed studies on alterations in small bowel motility are missing.

DESIGN

We evaluated 21 morbidly obese patients who underwent laparoscopic SG before and 4 months after the procedure. After consumption of a semisolid radiolabeled meal, their gastric and intestinal transit times were studied with a gamma camera. Particularly the times of 10% gastric emptying, 50% gastric emptying, maximal intestinal filling, 10% terminal ileum filling, duodenal to terminal ileum transit, cecal filling initiation, and ileocecal valve transit (T ICVt) were studied pre- and postoperatively.

RESULTS

Ten percent gastric emptying and 50% gastric emptying were decreased postoperatively as well as maximal intestinal filling, indicating faster gastric emptying and intestinal filling. Duodenal to terminal ileum transit and 10% terminal ileum filling also decreased as small bowel transit time accelerated and the meal reached the terminal ileum more rapidly. Contrary opening of the ileocecal valve and food transit through it were delayed, with postoperative increase in cecal filling initiation and T ICVt, respectively.

CONCLUSIONS

SG accelerates gastric emptying and small bowel transit of semisolids. In addition, it delays the initiation of cecal filling and T ICVt. This early and prolonged contact of food with the distal small bowel mucosa may explain the metabolic effects of SG occurring before substantial weight loss.

Visceral hypersensitivity and impaired accommodation in refractory diabetic gastroparesis

The pathophysiology of persistent gastrointestinal (GI) symptoms in patients with diabetic gastroparesis is poorly understood. Our aim was to evaluate gastric sensation and accommodation to a meal in patients with diabetic gastroparesis and refractory symptoms. We performed intermittent, phasic balloon distensions of the stomach using a gastric barostat device in 18 patients with diabetes and gastroparesis unresponsive to prokinetic therapy and in 13 healthy volunteers. We assessed the biomechanical, sensory and accommodation responses of the stomach, during fasting and after liquid meal. During balloon distension, the sensory thresholds for discomfort were lower (P < 0.02) in patients with diabetes than those in controls, in both the fasting and the postprandial states. The accommodation response to a meal was significantly impaired (P = 0.01) in patients with diabetes when compared to controls, although fasting gastric tone was similar (P = 0.08). Patients with diabetic gastroparesis and refractory GI symptoms demonstrate sensori-motor dysfunction of the stomach, comprising either impaired accommodation, gastric hypersensitivity or both. An objective evaluation of these biomechanical and sensory properties may provide valuable mechanistic insights that could guide therapy.

Postprandial gastric antral contractions in patients with gastro-oesophageal reflux disease: a scintigraphic study

Disturbed gastric contractility has been found in manometric studies in patients with gastro-oesophageal reflux disease (GORD), but the pathophysiological role of this abnormality is unclear. We aimed at assessing postprandial gastric antral contractions and its relationships with gastric emptying and gastro-oesophageal reflux in GORD patients. Fasted GORD patients (n = 13) and healthy volunteers (n = 13) ingested a liquid meal labelled with 72 MBq of 99mTechnetium-phytate. Gastric images were acquired every 10 min for 2 h, for measuring gastric emptying half time. Dynamic antral scintigraphy (one frame per second), performed for 4 min at 30-min intervals, allowed estimation of both mean dominant frequency and amplitude of antral contractions. In GORD patients (n = 10), acidic reflux episodes occurring 2 h after the ingestion of the same test meal were determined by ambulatory 24-h oesophageal pH monitoring. Gastric emptying was similar in GORD patients and controls (median; range: 82 min; 58-126 vs 80 min; 44-122 min; P = 0.38). Frequency of antral contractions was also similar in both groups (3.1 cpm; 2.8-3.6 vs 3.2 cpm; 2.4-3.8 cpm; P = 0.15). In GORD patients, amplitude of antral contractions was significantly higher than in controls (32.7%; 17-44%vs 23.3%; 16-43%; P = 0.01), and correlated positively with gastric emptying time (R(s) = 0.58; P = 0.03) and inversely with the number of reflux episodes (R(s) = -0.68; P = 0.02). Increased amplitude of postprandial gastric antral contractions in GORD may comprise a compensatory mechanism against delayed gastric emptying and a defensive factor against acidic gastro-oesophageal reflux.

Diminished functional association between proximal and distal gastric motility in critically ill patients

OBJECTIVE

This study examined the effects of critical illness on the relationship between proximal and distal gastric motor activity during fasting and duodenal nutrient stimulation.

DESIGN

Prospective, case-controlled study.

PATIENTS AND PARTICIPANTS

Ten critically ill patients and ten healthy volunteers.

INTERVENTIONS

Concurrent proximal gastric (barostat) and antro-pyloro-duodenal (manometry) motility were recorded during fasting and during two 60-min duodenal nutrient infusions (Ensure at 1 kcal/min and 2 kcal/min) in random order, separated by a 2-h wash-out period.

RESULTS

Baseline proximal gastric volumes were similar between the two groups. At 10 min nutrient-induced fundic relaxation was lower in patients than healthy subjects (45 +/- 26 vs. 196 +/- 29 ml). In patients the frequency and volume amplitude of fundic waves were also lower. There were fewer propagated antral waves in patients than in healthy subjects during both fasting and nutrient infusion. These were more retrograde, shorter in length and associated with a pyloric contraction. The proportion of fundic waves followed by a distally propagated antral wave was significantly less in patients (0%, 0-8%) than controls 36% (11-44%).

CONCLUSIONS

In critical illness, in addition to impairment of proximal and distal gastric motor activity, the association between the two gastric regions is abnormal. This disturbance may interfere with meal distribution and further contribute to slow gastric emptying in these patients.

Scintigraphic validation of AC Biosusceptometry to study the gastric motor activity and the intragastric distribution of food in humans

Abnormal intragastric distribution of food (IDF) and a phasic contractility in the proximal stomach have been related to dyspeptic symptoms. Thus, the behaviour of the stomach and the proximal region, in particular, continues to attract attention and demand for reliable and comfortable techniques. The aims of this study were to employ AC Biosusceptometry (ACB) and scintigraphy to evaluate IDF and gastric motor activity in humans. Fifteen healthy volunteers ingested 60 mL of yogurt containing 2 mCi of 99mTc and 4 g of ferrite. Each volunteer had gastric motility and IDF evaluated twice on separate days; on one occasion by ACB and another by scintigraphy. Digital signal processing was performed in MatLab (Mathworks Inc., Natick, MA, USA). Results were expressed as mean +/- SD. Similar results of distal accumulation time (P < 0.001) were obtained for scintigraphy (6.93 +/- 3.25 min) and for ACB (7.04 +/- 3.65 min). Fast Fourier Transform revealed two dominant frequencies (P > 0.9). Besides the well-know frequency of 3 cpm, our results showed identical frequencies in proximal stomach recordings (P < 0.001) for scintigraphic (1.01 +/- 0.01 cpm) and ACB (0.98 +/- 0.06 cpm). In summary, our data showed that scintigraphy and ACB are promising techniques to evaluate several aspects of gastric motility. Moreover, ACB is non-invasive, radiation-free and deserves the same importance as conventional methods for this kind of analysis.

Functional association between proximal and distal gastric motility during fasting and duodenal nutrient stimulation in humans

A functional integration exists between proximal and distal gastric motor activity in dogs but has not been demonstrated in humans. To determine the relationship between proximal and distal gastric motor activity in humans. Concurrent proximal (barostat) and distal (antro-pyloro-duodenal (APD) manometry) gastric motility were recorded in 10 healthy volunteers (28 +/- 3 years) during (i) fasting and (ii) two 60-min duodenal infusions of Ensure((R)) (1 and 2 kcal min(-1)) in random order. Proximal and APD motor activity and the association between fundic and propagated antral waves (PAWs) were determined. During fasting, 32% of fundic waves (FWs) were followed by a PAW. In a dose-dependent fashion, duodenal nutrients (i) increased proximal gastric volume, (ii) reduced fundic and antral wave (total and propagated) activity, and (iii) increased pyloric contractions. The proportion of FWs followed by a distal PAW was similar between both infusions and did not differ from fasting. During nutrient infusion, nearly all PAWs were antegrade, propagated over a shorter distance and less likely to traverse the pylorus, compared with fasting. In humans, a functional association exists between proximal and distal gastric motility during fasting and duodenal nutrient stimulation. This may have a role in optimizing intra-gastric meal distribution.

Contribution of sensitivity, volume and tone to visceral perception in the upper gastrointestinal tract in man: emphasis on testing

Upper gastrointestinal (GI) symptoms occur frequently in the general population, making them among the most common indications responsible for patients consulting the healthcare system. Consequently, understanding and characterization of the upper GI symptoms is important for the diagnosis and assessment of organ dysfunction. In practice, assessment of clinical symptoms is difficult and it is still to a large extent unclear how sensitivity, volume and tone contribute to visceral perception in the upper GI tract. The goal of advanced research in upper GI symptoms is to obtain a better understanding of the mechanisms involved in transduction, transmission, and perception under normal and pathophysiological conditions. An important step towards this goal is understanding the information provided by and the inherent limitations of the currently available measuring techniques. This article focuses on the sensory testing of the oesophagus, and methods and concepts used to assess the relation between gastric volumes or tone and upper GI symptoms. It also summarizes the contributions of these techniques towards identifying the components responsible for the generation of upper GI symptoms.

Effects of posture on the physiology of gastric emptying: a magnetic resonance imaging study

OBJECTIVE

Gastric contents empty from the stomach despite frequent changes in body position. The mechanism that maintains gastric emptying independent of position is poorly understood. The aim of this study was to determine the effects of body position on gastric emptying and motor function.

MATERIAL AND METHODS

Twelve volunteers were investigated in seated position (SP) and upside-down position (UDP) after ingestion of 300 ml water. Magnetic resonance imaging provided a non-invasive assessment of gastric emptying and volumes, intragastric distribution and peristaltic function.

RESULTS

A marked difference in distal/proximal intragastric distribution between UDP and SP was present (7% versus 40%; p < 0.01). Gastric-emptying time was similar but emptying pattern was linear in UDP and exponential in SP. Peristalsis was slower in UDP than SP (2.75 versus 2.96 min-1; p < 0.01), but no correlation was found between peristaltic frequency and the rate of gastric emptying in either position. Postprandial volume response (gastric relaxation) was greater in UDP than SP (280 versus 250 ml; p < 0.05). A correlation was found between gastric relaxation and gastric-emptying time in SP (r2=0.46) but not in UDP.

CONCLUSIONS

The stomach maintains the rate of gastric emptying despite radical changes in body position and intragastric distribution of gastric contents. In SP, hydrostatic pressure (modulated by gastric tone) dictates the gastric emptying. In UDP, gastric emptying also appears to be mediated by continuous adaptation of gastric tone. These findings provide support for the hypothesis that the mechanism of gastric emptying resembles a "pressure pump" rather than a "peristaltic pump".

Review article: a critical view on impaired accommodation as therapeutic target for functional dyspepsia

Several important pathophysiological mechanisms have been identified in functional dyspepsia, however a complete understanding of these mechanisms and beneficial therapeutic strategies are still lacking. Based on the currently available literature we aimed at providing a critical view on one of these pathophysiological mechanisms, impaired accommodation. Although impaired gastric accommodation is identified as a major pathophysiological mechanism, the clinical evidence supporting its role as an important therapeutic target is currently still lacking. Treatment with fundic relaxant drugs has shown conflicting results and has been rather disappointing in general. These negative findings could be explained by the fact that impaired fundic accommodation is part of a more complex disorder involving other regions of the proximal gut or by the increasing insight that central mechanisms may play an important role. Future studies of impaired accommodation should take these considerations into account.

Relationships between intragastric food maldistribution, disturbances of antral contractility, and symptoms in functional dyspepsia

We investigated the relationships between intragastric food maldistribution and antral dysmotility in functional dyspepsia, and whether these abnormalities relate to meal-induced symptoms. Intragastric distribution of food throughout gastric emptying was determined in patients (n = 24) and controls (n = 38) after a liquid nutrient meal labeled with (99m)technetium phytate. Antral contractility was also periodically assessed by dynamic scintigraphy and postprandial symptoms were monitored with visual analog scales. Residence of food in the proximal stomach was decreased in 8 (33%) and antral contractility was increased in 9 (37.5%) and decreased in 2 (8%) patients. Proximal and distal stomach motor abnormalities were neither significantly correlated nor associated. Increased antral contractility was significantly correlated (Rs = 0.54; P < .01) with postprandial nausea. We conclude that diminished residence of food in the proximal stomach and disturbed antral contractility occur independently in different subsets of functional dyspepsia patients. Increased antral contractility seems to play a role in postprandial nausea in functional dyspepsia.

Investigation of fundo-antral reflex in human beings

AIM: To examine the sensory and motor response(s) of the stomach following fundic distention and to assess whether cholinergic mechanisms influence these responses.

METHODS: Fundic tone, gastric sensory responses and antral motility were evaluated in eight healthy volunteers after a probe with two sensors was placed in the antrum and a highly compliant balloon in the fundus. Isobaric balloon distentions were performed with a barostat. Study was repeated in six volunteers after intravenous atropine was given.

RESULTS: Fundic distention induced large amplitude antral contractions in all subjects. The area under the curve was higher (P<0.05) during fundic distention. First sensation was reported at 12±4 mmHg, moderate sensation at 18±4 mmHg and discomfort at 21±4 mmHg. Discomfort was associated with a decrease in antral motility. After atropine was given, the area under the curve of pressure waves and fundic tone decreased (P<0.05). Sensory thresholds were not affected.

CONCLUSIONS: Fundic balloon distention induces an antral motor response, the fundo-antral reflex, which in part may be mediated by cholinergic mechanisms.