Effect of endoscopic sclerotherapy of esophageal varices on vagus nerve integrity

Gastroparesis

Gastroparesis is characterized by symptoms suggestive of, and objective evidence of, delayed gastric emptying in the absence of mechanical obstruction. This review addresses the normal emptying of solids and liquids from the stomach and details the myogenic and neuromuscular control mechanisms, including the specialized function of the pyloric sphincter, that result in normal emptying, based predominantly on animal research. A clear understanding of fundamental mechanisms is necessary to comprehend derangements leading to gastroparesis, and additional research on human gastric muscles is needed. The section on pathophysiology of gastroparesis considers neuromuscular diseases that affect nonsphincteric gastric muscle, disorders of the extrinsic neural control, and pyloric dysfunction that lead to gastroparesis. The potential cellular basis for gastroparesis is attributed to the effects of oxidative stress and inflammation, with increased pro-inflammatory and decreased resident macrophages, as observed in full-thickness biopsies from patients with gastroparesis. Predominant diagnostic tests involving measurements of gastric emptying, the use of a functional luminal imaging probe, and high-resolution antral duodenal manometry in characterizing the abnormal motor functions at the gastroduodenal junction are discussed. Management is based on supporting nutrition; dietary interventions, including the physical reduction in particle size of solid foods; pharmacological agents, including prokinetics and anti-emetics; and interventions such as gastric electrical stimulation and pyloromyotomy. These are discussed briefly, and comment is added on the potential for individualized treatments in the future, based on optimal gastric emptying measurement and objective documentation of the underlying pathophysiology causing the gastroparesis.

Relationship of motor mechanisms to gastroparesis symptoms: toward individualized treatment

Following a classical paper by Dr. Keith A. Kelly published in this journal, and over the past 40 years, there has been increased understanding of the functions of different regions of the stomach, specifically the fundus, antrum, and pylorus. Several of the important physiological principles were based on in vivo animal studies that led to the appreciation of regional function and control mechanisms. These include the roles of the extrinsic parasympathetic vagal innervation, the gastric enteric nervous system and electrical syncytium consisting of pacemaker cells and smooth muscle cells, and duodenogastric reflexes providing feedback regulation following the arrival of food and hydrogen ions stimulating the release of hormones and vagal afferent mechanisms that inhibit gastric motility and stimulate pyloric contractility. Further insights on the role of regional motor functions in gastric emptying were obtained from observations in patients following diverse gastric surgeries or bariatric procedures, including fundoplication, Billroth I and sleeve gastrectomy, and sleeve gastroplasty. Antropyloroduodenal manometry and measurements of pyloric diameter and distensibility index provided important assessments of the role of antral hypomotility and pylorospasm, and these constitute specific targets for individualized treatment of patients with gastroparesis. Moreover, in patients with upper gastrointestinal symptoms suggestive of gastroparesis, the availability of measurements of gastric accommodation and pharmacological agents to reduce gastric sensitivity or enhance gastric accommodation provide additional specific targets for individualized treatment. It is anticipated that, in the future, such physiological measurements will be applied in patients to optimize choice of therapy, possibly including identifying the best candidate for pyloric interventions.

Spectrum of esophageal motility disorders in patients with liver cirrhosis

Disorders of esophageal motility have been described in patients with cirrhosis in a small number of studies. In this review, we aim to provide an overview of the available evidence on esophageal motility disorders in cirrhosis and their clinical implications. This review delves into the following concepts: (1) Gastroesophageal reflux disease is common in liver cirrhosis due to many mechanisms; however, when symptomatic it is usually nocturnal and has an atypical presentation; (2) Endoscopic band ligation is better than sclerotherapy in terms of its effect on esophageal motility and seems to correct dysmotilities resulting from the mechanical effect of esophageal varices; (3) Chronic alcoholism has no major effects on esophageal motility activity other than lower esophageal sphincter hypertension among those with alcoholic autonomic neuropathy; (4) An association between primary biliary cholangitis and scleroderma can be present and esophageal hypomotility is not uncommon in this scenario; and (5) Cyclosporin-based immunosuppression in liver transplant patients can have a neurotoxic effect on the esophageal myenteric plexus leading to reversible achalasia-like manifestations.

Gastrointestinal Motility Disorders and Their Clinical Implications in Cirrhosis

Gastrointestinal motility is impaired in a substantial proportion of patients with cirrhosis. Cirrhosis-related autonomic neuropathy, increased nitric oxide production, and gut hormonal changes have been implicated. Oesophageal dysmotility has been associated with increased frequency of abnormal gastro-oesophageal reflux. Impaired gastric emptying and accommodation may result in early satiety and may have an impact on the nutritional status of these patients. Small intestinal dysmotility might be implicated in small intestinal bacterial overgrowth and increased bacterial translocation. The latter has been implicated in the pathophysiology of hepatic encephalopathy and spontaneous bacterial peritonitis. Enhanced colonic motility is usually associated with the use of lactulose. Pharmacological interventions aiming to alter gastrointestinal motility in cirrhosis could potentially have a beneficial effect reducing the risk of hepatic decompensation and improving prognosis.

Management of gastroparesis-associated malnutrition

Gastroparesis (GP) is a chronic debilitating dysmotility characterized by unrelenting nausea, vomiting, bloating, early satiety, postprandial fullness and abdominal pain. Patients with GP experience other associated conditions, including gastroesophageal reflux disease, gastric bezoars and small bowel bacterial overgrowth. Furthermore, GP is associated with poor quality of life, increased emergency room visits, hospitalizations and subsequent increased healthcare costs. Currently, the managements of GP consist of glycemic control, antiemetics, prokinetics and the use of gastric electrical stimulation. However, most GP patients are at risk for significant nutritional abnormalities. As such, it is essential to screen and diagnose malnutrition in these patients. Poor oral intake in such patients could be supplemented by enteral tube feeding. Parenteral nutrition, although a last resort, is associated with a number of complications and should be used only for the short term. In summary, a systematic approach including initial nutritional screening, diet recommendations, medical therapy, nutritional re-evaluation and enteral and parental nutrition should be considered in complex GP patients.

[Gastroparesis. Definition, diagnostics, and therapy]

Gastroparesis is characterized by a constellation of upper gastrointestinal symptoms in association with delayed gastric emptying in the absence of mechanical outlet obstruction from the stomach. Major symptoms are nausea, vomiting, early satiety or postprandial fullness, bloating, and abdominal or epigastric pain. Idiopathic, diabetic, and postsurgical causes represent the most common etiologies. Diagnostic procedures for the evaluation of gastroparesis comprise gastric emptying scintigraphy (gold standard), (13)C-octanoate breath testing, and a wireless motility capsule. Management of gastroparesis includes normalization of nutritional state, relief of symptoms, glycemic control, and improvement of gastric emptying. Medical treatment entails use of prokinetic drugs, which are currently the first-line therapy. Nausea and vomiting might be positively influenced by antiemetic drugs. Gastric electronic stimulation and surgical interventions should be used in well-defined patients and represent a therapeutic option in tertiary centers.

Gastroparesis: approach, diagnostic evaluation, and management

Gastroparesis is a chronic motility disorder of the stomach that involves delayed emptying of solids and liquids, without evidence of mechanical obstruction. Although no cause can be determined for the majority of cases, the disease often develops as a complication of abdominal surgeries or because of other underlying disorders, such as diabetes mellitus or scleroderma. The pathophysiology behind delayed gastric emptying is still not well-understood, but encompasses abnormalities at 3 levels--autonomic nervous system, smooth muscle cells, and enteric neurons. Patients will often cite nausea, vomiting, postprandial fullness, and early satiety as their most bothersome symptoms on history and physical examination. Those that present with severe disease may already have developed complications, such as the formation of bezoars or masses of undigested food. In patients suspected of gastroparesis, diagnostic evaluation requires an initial upper endoscopy to rule out mechanical causes, followed by a gastric-emptying scintigraphy for diagnosis. Other diagnostic alternatives would be wireless capsule motility, antroduodenal manometry, and breath testing. Once gastroparesis is diagnosed, dietary modifications, such as the recommendation of more frequent and more liquid-based meals, are encouraged. Promotility medications like erythromycin and antiemetics like prochlorperazine are offered for symptomatic relief. These agents may be frequently changed, as the right combination of effective medications will vary with each individual. In patients who are refractory to pharmacologic treatment, more invasive options, such as intrapyloric botulinum toxin injections, placement of a jejunostomy tube, or implantation of a gastric stimulator, are considered. Future areas of research are based on current findings from clinical studies. New medications, such as hemin therapy, are emerging because of a better understanding of the pathophysiology behind gastroparesis, and present treatment options, such as gastric electric stimulation, are evolving to be more effective. Regenerative medicine and stem cell-based therapies also hold promise for gastroparesis in the near future.

Gastric emptying and vagus nerve function after laparoscopic partial fundoplication

OBJECTIVE

To establish the relation between vagus nerve dysfunction, gastric emptying, and antireflux surgery.

SUMMARY BACKGROUND DATA

Delayed gastric emptying occurs in up to 40% of reflux patients. After antireflux surgery, gastric emptying becomes normal or is even accelerated. Occasionally, severe gastric stasis is found and is associated with a negative outcome of the antireflux procedure. It has been suggested that injury to the vagus nerve could be the cause of this delayed emptying.

METHODS

We evaluated in a prospective study gastric emptying of solids and vagus nerve function (pancreatic polypeptide response to hypoglycemia) before and after surgery in 41 patients (22 women; age 43 +/- 1.6 years) who underwent laparoscopic hemifundoplication.

RESULTS

All patients had relief of reflux symptoms varying from adequate (n = 8) to complete relief (n = 33). Gastric emptying of solids increased significantly (P < 0.001) after operation: lag phase from 19 +/- 2 to 10 +/- 1 minute, emptying rate (%/h) from 37 +/- 2 to 48 +/- 5 and half emptying time from 110 +/- 8 to 81 +/- 4 minutes. Gastric emptying improved to a similar extent in patients with delayed and normal preoperative gastric emptying. Postoperative signs of vagus nerve damage (PP peak < 47pmol/L) were present in 4 patients (10%). In these 4 patients gastric emptying both before and after operation did not differ from patients with normal vagus nerve function. In fact, none of the 41 patients had severely delayed emptying after laparoscopic hemifundoplication.

CONCLUSIONS

Laparoscopic hemifundoplication affects vagus nerve integrity in 10% of patients, but this does not lead to a delay in gastric emptying. In fact, gastric emptying improved significantly after fundoplication.

Function of the proximal stomach after partial versus complete laparoscopic fundoplication

OBJECTIVES

After antireflux surgery, more than 30% of patients develop dyspeptic symptoms such as fullness and early satiety. We have previously shown that these symptoms are related to fundoplication-induced changes in proximal gastric motor and sensory function, especially impaired postprandial relaxation. We hypothesize that impaired fundus relaxation may be more pronounced after complete versus partial fundoplication.

METHODS

Fasting and postprandial proximal gastric motor and sensory function were measured with an electronic barostat in patients after laparoscopic partial (n = 14) and complete (n = 14) fundoplication, in gastroesophageal reflux disease (GERD) patients (n = 12), and in healthy control subjects (n = 15). Gastric emptying and vagus nerve function tests were performed in all patients.

RESULTS

Minimal distending pressure (MDP) and proximal gastric compliance were not significantly different among patients after antireflux surgery, GERD patients, and healthy controls. Maximal postprandial fundus relaxation was significantly (p < 0.01) reduced in patients after partial (267 +/- 32 ml) and complete (294 +/- 34 ml) fundoplication compared with GERD patients (448 +/- 30 ml) and healthy controls (409 +/- 25 ml). Sensations of fullness were not significantly different between patients with partial and complete fundoplication. There was a significant positive correlation between the postoperative duration and the degree of postprandial fundus relaxation (r = 0.67; p < 0.001).

CONCLUSIONS

Both after complete and after partial fundoplication, proximal gastric motor function is affected, with impaired postprandial relaxation and increased sensation of fullness. These alterations are not related to the type of fundoplication but correlate significantly with the duration of the postoperative period.

Prospective study of the effect of laparoscopic Nissen fundoplication on reflux mechanisms

BACKGROUND

Laparoscopic Nissen fundoplication effectively reduces acid reflux and reflux symptoms. Little is known about the effect on reflux mechanisms, especially on transient lower oesophageal sphincter relaxations (TLOSRs).

METHODS

Twenty-seven patients were studied prospectively before and after laparoscopic Nissen fundoplication, by simultaneous recording of pH and lower oesophageal sphincter (LOS) characteristics using sleeve manometry. In all of the 27 patients the operation was judged successful, based on major improvement or resolution of reflux symptoms and acid reflux. Vagus nerve integrity was studied indirectly by the secretion of pancreatic polypeptide (PP) in response to insulin-induced hypoglycaemia.

RESULTS

After fundoplication basal LOS pressure increased significantly from mean(s.e.m.) 13(1) to 22(1) mmHg (P < 0.001). Laparoscopic Nissen fundoplication significantly decreased the frequency of TLOSR in the fasting period from mean(s.e.m.) 2.5(0.5) to 0.6(0.2) per h, and in the postprandial period from 4.0(0.4) to 1.3(0.3) per h (P < 0.01). The percentage of TLOSRs associated with reflux also decreased significantly from 24(10) to 0(0) per cent in the fasting period and from 42(6) to 12(6) per cent in the postprandial period, before and after fundoplication respectively (P < 0.01). After operation the PP response was abnormal in three patients, pointing to vagus nerve dysfunction. Postoperative TLOSR frequency and LOS pressure were no different between patients with and without vagus nerve dysfunction.

CONCLUSION

Laparoscopic Nissen fundoplication significantly increased fasting and postprandial LOS pressure and significantly decreased the rate of TLOSR. This resulted in a significant reduction in oesophageal acid exposure but postprandial LOS characteristics were preserved.

Prospective study of the effect of laparoscopic hemifundoplication on motor and sensory function of the proximal stomach

BACKGROUND

Some 30 per cent of patients develop dyspeptic symptoms following antireflux surgery. These symptoms may result from alterations in the motor and sensory function of the proximal stomach.

METHODS

Proximal gastric motor and sensory function was studied with an electronic barostat in 12 patients with reflux who underwent laparoscopic hemifundoplication. In addition, 24-h pHmetry, gastric emptying (scintigraphy) and vagus nerve integrity (pancreatic polypeptide response to hypo-glycaemia) were assessed. Fifteen healthy volunteers served as controls.

RESULTS

Laparoscopic hemifundoplication significantly decreased total acid exposure time (P < 0.05). Vagus nerve function remained intact in all but one patient. The mean(s.e.m.) lag phase for emptying of solids was significantly shorter after operation than before (15(3) versus 21(3) min; P < 0.05). Proximal gastric compliance was not significantly different before and after fundoplication. However, mean(s.e.m.) postprandial relaxation was significantly reduced (P < 0.05) after hemifundoplication compared with the value before operation (3341(1105) versus 12 763(3616) ml over 90 min) and in controls (14 567(2358) ml over 90 min). Postprandial fullness was significantly increased after hemi-fundoplication (P < 0.05). Postprandial gastric relaxation correlated with the lag phase for emptying of solids (r = 0.55, P < 0.02).

CONCLUSION

After hemifundoplication, proximal gastric compliance is not altered but postprandial relaxation is impaired and associated with sensations of fullness and shorter duration of the lag phase for emptying of solids.

Motor and sensory function of the proximal stomach in reflux disease and after laparoscopic Nissen fundoplication

OBJECTIVE

After Nissen fundoplication, dyspeptic symptoms such as fullness and early satiety develop in >30% of patients. These symptoms may result from alterations in proximal gastric motor and sensory function.

METHODS

We have evaluated proximal gastric motor and sensory function using an electronic barostat in 12 patients after successful laparoscopic Nissen fundoplications (median follow-up; 12 months). Twelve age- and gender-matched patients with severe gastroesophageal reflux disease (GERD) and 12 healthy volunteers served as controls. Studies were performed in the fasting state and after meal ingestion. Gastric emptying tests were performed in all patients. Vagus nerve integrity was measured by the response of pancreatic polypeptide (PP) to insulin hypoglycemia.

RESULTS

Minimal distending pressure and proximal gastric compliance were not significantly different between post-Nissen patients, GERD patients, and healthy controls. Postprandial relaxation of the stomach, however, was significantly (p < 0.05) reduced post-Nissen (267 +/- 34 ml), compared with controls (400 +/- 30 ml) and GERD (448 +/- 30 ml). Postprandial relaxation was significantly (p < 0.01) prolonged in GERD patients. Postprandial relaxation of the stomach correlated with gastric emptying of solids (r = 0.62; p = 0.01). Gastric emptying of solids became significantly (p < 0.05) faster after fundoplication. Postprandial fullness was significantly (p < 0.05) increased in the operated patients.

CONCLUSIONS

Post-Nissen patients have a significantly reduced postprandial gastric relaxation and significantly accelerated gastric emptying, which may explain postoperative dyspeptic symptoms. The abnormalities result from fundoplication and not from vagus nerve injury or reflux per se, because in reflux patients gastric relaxation and gastric emptying are prolonged.