Faecal fat excretion after truncal, selective, and highly selective vagotomy for duodenal ulcer

Metabolic effects of truncal vagotomy when combined with bariatric-metabolic surgery

Bariatric-metabolic surgery (BMS) in patients with obesity frequently leads to remission of concurrent type 2 diabetes mellitus (T2DM), even before body weight loss takes place. This is probably based on the correction of a dysmetabolic cycle in the gastrointestinal physiology of T2DM that includes increased vagus-dependent exocrine pancreatic secretion (EPS) and, hence, amplified digestion and nutrient absorption. The resultant chronic exposure of tissues to high plasma levels of glucose, fatty acids and amino acids causes tissue resistance to the actions of insulin and, at a later stage, β-cell dysfunction and reduction of insulin release. We hypothesize that the addition of a surgical truncal vagotomy (TV) may improve and solidify the beneficial results of BMS on T2DM by stably decreasing EPS, - hence reducing the digestion and absorption of nutrients -, and increasing incretin secretion as a result of increased delivery of unabsorbed nutrients to the distal intestine. This hypothesis is supported by surgical data from gastrointestinal malignancies and peptic ulcer operations that include TV, as well as by vagal blockade studies. We suggest that TV may result in a stable reduction of EPS, and that its combination with the appropriate type of BΜS, may enhance and sustain the salutary effects of the latter on T2DM.

Less common etiologies of exocrine pancreatic insufficiency

Exocrine pancreatic insufficiency (EPI), an important cause of maldigestion and malabsorption, results from primary pancreatic diseases or secondarily impaired exocrine pancreatic function. Besides cystic fibrosis and chronic pancreatitis, the most common etiologies of EPI, other causes of EPI include unresectable pancreatic cancer, metabolic diseases (diabetes); impaired hormonal stimulation of exocrine pancreatic secretion by cholecystokinin (CCK); celiac or inflammatory bowel disease (IBD) due to loss of intestinal brush border proteins; and gastrointestinal surgery (asynchrony between motor and secretory functions, impaired enteropancreatic feedback, and inadequate mixing of pancreatic secretions with food). This paper reviews such conditions that have less straightforward associations with EPI and examines the role of pancreatic enzyme replacement therapy (PERT). Relevant literature was identified by database searches. Most patients with inoperable pancreatic cancer develop EPI (66%-92%). EPI occurs in patients with type 1 (26%-57%) or type 2 diabetes (20%-36%) and is typically mild to moderate; by definition, all patients with type 3c (pancreatogenic) diabetes have EPI. EPI occurs in untreated celiac disease (4%-80%), but typically resolves on a gluten-free diet. EPI manifests in patients with IBD (14%-74%) and up to 100% of gastrointestinal surgery patients (47%-100%; dependent on surgical site). With the paucity of published studies on PERT use for these conditions, recommendations for or against PERT use remain ambiguous. The authors conclude that there is an urgent need to conduct robust clinical studies to understand the validity and nature of associations between EPI and medical conditions beyond those with proven mechanisms, and examine the potential role for PERT.

Neural regulation of intestinal nutrient absorption

The nervous system and the gastrointestinal (GI) tract share several common features including reciprocal interconnections and several neurotransmitters and peptides known as gut peptides, neuropeptides or hormones. The processes of digestion, secretion of digestive enzymes and then absorption are regulated by the neuro-endocrine system. Luminal glucose enhances its own absorption through a neuronal reflex that involves capsaicin sensitive primary afferent (CSPA) fibres. Absorbed glucose stimulates insulin release that activates hepatoenteric neural pathways leading to an increase in the expression of glucose transporters. Adrenergic innervation increases glucose absorption through α1 and β receptors and decreases absorption through activation of α2 receptors. The vagus nerve plays an important role in the regulation of diurnal variation in transporter expression and in anticipation to food intake. Vagal CSPAs exert tonic inhibitory effects on amino acid absorption. It also plays an important role in the mediation of the inhibitory effect of intestinal amino acids on their own absorption at the level of proximal or distal segment. However, chronic extrinsic denervation leads to a decrease in intestinal amino acid absorption. Conversely, adrenergic agonists as well as activation of CSPA fibres enhance peptides uptake through the peptide transporter PEPT1. Finally, intestinal innervation plays a minimal role in the absorption of fat digestion products. Intestinal absorption of nutrients is a basic vital mechanism that depends essentially on the function of intestinal mucosa. However, intrinsic and extrinsic neural mechanisms that rely on several redundant loops are involved in immediate and long-term control of the outcome of intestinal function.

Selection of electrical algorithms to treat obesity with intermittent vagal block using an implantable medical device

BACKGROUND

A laparoscopically implantable electrical device that intermittently blocks both vagi near the esophagogastric junction led to significant excess weight loss (EWL) in an initial clinical trial in obese patients. The study objective was to optimize therapy algorithms and determine the EWL achieved with a second-generation device at university hospitals in Australia, Norway, and Switzerland.

METHODS

Data acquired during the initial clinical trial were analyzed and subsequently used to select alternative electrical algorithms. In the second trial, vagal blocking using one selected therapy algorithm was initiated 2 weeks after implanting the second-generation device. The patients were followed up for 6 months to assess the EWL and safety, including adverse events.

RESULTS

In the initial clinical trial, vagal blocking algorithm durations of 90-150 s were associated with greater EWL compared with either shorter or longer algorithm durations (P<.01). The second trial enrolled 27 patients (mean body mass index 39.3+/-.8 kg/m2) to evaluate a 120-s blocking algorithm. At 6 months, greater EWL was achieved (22.7%+/-3.1%, n=24) compared with the initial study and first-generation device (14.2%+/-2.2%, n=29, P=.03). In both trials, an association was found between the number of 90-150-s algorithms delivered daily and greater EWL (P=.03). No deaths, unanticipated device-related adverse events, or medically serious adverse events were associated with the device.

CONCLUSION

This second-generation vagal blocking device, using a therapy algorithm of 120-s duration, resulted in a clinically acceptable safety profile and significantly greater EWL compared with the first-generation device delivering a wider range of therapy algorithm durations.

Stimulation of jejunal synthesis of apolipoprotein A-IV by ileal lipid infusion is blocked by vagotomy

We examined the role of vagal innervation in lipid-stimulated increases in expression and synthesis of intestinal apolipoprotein A-IV (apoA-IV). In rats with duodenal cannulas and superior mesenteric lymph fistulas given duodenal infusions of lipid emulsion, vagotomy had no effect on either intestinal lipid transport, lymphatic apoA-IV output, or jejunal mucosal apoA-IV synthesis. In rats with jejunal Thiry-Vella fistulas, ileal lipid infusion elicited a twofold stimulation of apoA-IV synthesis without affecting apoA-IV mRNA levels; vagotomy blocked this increase in apoA-IV synthesis. Direct perfusion of jejunal Thiry-Vella fistulas produced 2- to 2.5-fold increases in both apoA-IV synthesis and mRNA levels in the Thiry-Vella segment; these effects were not influenced by vagal denervation. These results suggest two mechanisms whereby lipid stimulates intestinal apoA-IV production: 1) a vagal-dependent stimulation of jejunal apoA-IV synthesis by distal gut lipid that is independent of changes in apoA-IV mRNA levels and 2) a direct stimulatory effect of proximal gut lipid on both synthesis and mRNA levels of jejunal apoA-IV that is independent of vagal innervation.

Outcome analysis of long-term survivors following pancreaticoduodenectomy

The long-term sequelae of pancreaticoduodenectomy are not completely understood. In the present study nutritional status, pancreatic function, and subjective quality-of-life parameters were evaluated in 45 patients who had previously undergone either pylorus-preserving pancreaticoduodenectomy (PPPD) or standard pancreaticoduodenectomy (SPD). Quality-of-life parameters, as measured by the Short Form-36 health survey, demonstrated no significant differences between the subgroups and normal control subjects in six of the eight domains for physical and mental health. Patients who had undergone SPD were noted to have significantly lower scores for general health and vitality than either age-matched control subjects or those who had undergone PPPD. No differences in nutritional parameters or indicators of pancreatic exocrine function between the two groups were identified. An elevated hemoglobin A1c value was seen in only one patient who was not diabetic preoperatively. Our data indicate that long-term survivors of pancreaticoduodenectomy generally feel as good as their normal counterparts, although SPD may result in some health satisfaction deficits. Nutritional status and pancreatic exocrine function are not improved in patients undergoing a pylorus-preserving procedure, and postoperative pancreatic endocrine dysfunction is unusual in both groups.

Effect of D2-dopamine receptor antagonist levosulpiride on diabetic cholecystoparesis: a double-blind crossover study

BACKGROUND

Abnormal gall-bladder motility has been reported in diabetics. The objective was to evaluate the effect of chronic D2-dopamine receptor inhibition on gall-bladder emptying in diabetic patients.

METHODS

Under double-blind placebo-controlled conditions and according to a crossover design, patients were randomly assigned to receive either 4 weeks treatment with levosulpiride 25 mg t.d.s. or 4 weeks treatment with placebo, with an interval of 15 days. Twenty-three consecutive long-standing, insulin-treated diabetics with autonomic neuropathy were studied.

MEASUREMENTS

At the beginning of the study and after levosulpiride or placebo treatment, gall-bladder emptying was measured ultrasonically by evaluating the gall-bladder volume in basal conditions and every 15 min for 90 min after the ingestion of a standard meal. Statistical analysis of the results was performed by means of analysis of variance.

RESULTS

Levosulpiride treatment reduced the basal mean gall-bladder volume from 21.6 +/- 2.3 to 18.6 +/- 2.3 mL (P < 0.05). Furthermore, the residual gall-bladder volume (9.3 +/- 1.4 mL) was significantly reduced compared to the corresponding pre-treatment volume (14.6 +/- 1.5 mL (P < 0.05). In placebo-treated patients, no significant differences were observed in gall-bladder volumes before and after treatment.

CONCLUSION

These results show that chronic oral administration of the D2-dopamine antagonist levosulpiride has a significant effect on gall-bladder motility in diabetic patients.

Current status of proximal gastric vagotomy

Proximal gastric vagotomy is nearing its twentieth year in clinical use as an operation for peptic ulcer disease. No other acid-reducing operation has undergone as much scrutiny or study. At this time, the evidence of such studies and long-term follow-up strongly supports the use of proximal gastric vagotomy as the treatment of choice for chronic duodenal ulcer in patients who have failed medical therapy. Its application in treating the complications of peptic ulcer disease, which recently have come to represent an increasingly greater percentage of all operations done for peptic ulcer disease, is well-tested. However, initial series suggest that it should probably occupy a prominent role in treating some of these complications, particularly in selected patients, in the future. The operation has the well-documented ability to reduce gastric acid production, not inhibit gastric bicarbonate production, and also minimally inhibit gastric motility. The combination of these physiologic results after proximal gastric vagotomy, along with preservation of the normal antropyloroduodenal mechanism of gastrointestinal control, serve to allow patients with proximal gastric vagotomy the improved benefits of significantly fewer severe gastrointestinal side effects than are seen after other operations for peptic ulcer disease.

Preduodenal mechanisms in initiating gallbladder emptying in man

The existence of preduodenal phases of gallbladder emptying in normal volunteers was investigated by evaluating the effect of sham feeding a sandwich (chew and spit) (n = 15), the sight and smell of food followed by sham feeding a cooked meal (n = 15), and gastric distension (intragastric balloon tube) (n = 9) on gallbladder emptying and comparing these responses with those after ingestion of a standard meal (n = 14). A control group given no intestinal stimuli were studied to determine the frequency of spontaneous emptying during fasting (n = 18). 99mTc-EHIDA (2,6 diethylphenylcarbamoylmethyliminodiacetic acid) was used as the biliary tracer. The frequency of gallbladder emptying during fasting was 0.0045/min. Thus, in any 20 min period emptying occurred spontaneously in only about 1 in 11 volunteers. Significant emptying (greater than 5 per cent over 20 min) occurred in 8 out of 15 volunteers after sham feeding a sandwich (P less than 0.001 versus control), in 8 out of 15 volunteers after sham feeding a cooked meal (P = 1.0 versus sandwich sham feed, n.s.), in 6 out of 9 volunteers after gastric distension (P less than 0.001 versus control) and in 14 out of 14 volunteers after meal ingestion. The rate of emptying was significantly greater in the gastric distension and meal ingestion groups compared with other groups (P less than 0.05). However, the emptying rate after sham feeding was not significantly different from spontaneous gallbladder emptying (P greater than 0.05, n.s.). There was no significant difference in time to onset of emptying between the four stimulus groups (P greater than 0.05, n.s.). These results suggest that pre-duodenal stimuli can evoke gallbladder emptying in man, although the precise physiological significance of this phenomenon remains to be established.

Relationship between gastric emptying of a solid meal and emptying of the gall bladder before and after vagotomy

Little is known of the temporal and quantitative relationships between emptying of the stomach and of the gall bladder in patients with duodenal ulcer before and after vagotomy. A non-invasive double isotope technique was used to investigate these relationships in 27 patients with a duodenal ulcer, before and after operation-truncal vagotomy and pyloroplasty (TV + P; n = 15) and highly selective vagotomy (HSV; n = 12). A further 25 patients were studied after operation (TV + P, n = 20: HSV, n = 5). 99Tcm-EHIDA was used as the biliary tracer and 113Inm bran as the gastric content tracer. In patients with a duodenal ulcer before surgery and in 16 of the 17 patients studied after HSV, the patterns of gall bladder emptying were similar to those previously found in normal subjects. In 60% of patients after TV + P, patterns of gall bladder emptying were altered and the onset of gall bladder emptying was significantly delayed (p less than 0.001) compared with unoperated patients and patients with a HSV. The rate of gall bladder emptying did not correlate with the rate of gastric emptying in any of the patients studied. These observations suggest that TV + P, but not HSV, causes considerable alteration in coordination of gall bladder and gastric emptying.

Should it be parietal cell vagotomy or selective vagotomy-antrectomy for treatment of duodenal ulcer? A progress report

This is a progress report of a prospective, randomized study involving 200 consecutive patients treated electively with either parietal cell vagotomy (PCV) or selective vagotomy and antrectomy (SV-A). Both groups comprised patients with pyloric, prepyloric, or duodenal ulcers. There was no operative mortality in either group. Patients were examined at 2, 6, 12 months, and every 12 months thereafter for 8-10 years. The two operations produced no statistical difference in the frequency of diarrhea. Dumping (p less than 0.0005) and weight loss (p less than 0.0005-p less than 0.05) were statistically less after PCV than after SV-A. There were two recurrent ulcers (2.2%) after SV-A. One was treated successfully by medical therapy and one patient suspected of having gastrinoma had total vagotomy. Nine patients had recurrent ulcers in the PCV group for an accumulated recurrence rate of 10.1% at 10 years by life-table analysis. There was a significant difference (p less than 0.033) between the curves for recurrent ulcers in the two groups of patients. The recurrent ulcer rate after PCV was 21% for patients with pyloric and prepyloric ulcers and 6% for patients with duodenal ulcer. There was no significant difference between the recurrent ulcer rate for PCV and SV-A if the patients with pyloric and prepyloric ulcers were withdrawn from the study. Of the nine patients with recurrent ulcers in the PCV group, three had an inadequate vagotomy and four had a pyloric or prepyloric ulcer before operation. Three patients were successfully treated with antrectomy. Five patients were treated successfully by medical therapy and remained healed for long periods without recurrence. One patient had five recurrences. He declined operation and remained free of symptoms for 3 years after his last recurrence. Poor gastric emptying necessitated gastroenterostomy in five patients in the SV-A group and in one patient in the PCV group. Patients' clinical results were evaluated according to a simple Visick grading scale. A significantly (p less than 0.0005) greater number of patients were in Visick I category after PCV than after SV-A. The clinical results obtained with PCV make this the operation of choice for the elective surgical treatment of duodenal ulcers even though the results obtained with SV-A were good.

Relationship between gastric emptying of solids and gall bladder emptying in normal subjects

Very little is known about the normal temporal and quantitative relationships between gastric emptying and gall bladder emptying. Using a non-invasive double isotope technique these relationships were investigated in 22 normal healthy adults. 99Tcm EHIDA was used as the biliary tracer and 113Inm labelled bran as the gastric content tracer. Gastric emptying was monoexponential with a t1/2 of 45 +/- 3 minutes (mean +/- SEM). In 15 subjects the gall bladder emptied in relation to eating according to a double exponential function. In these subjects 15.0 +/- 1.6% of gall bladder contents emptied before gastric emptying began. They could be further divided into two clear cut types (p less than 0.001), according to the ejection fraction at 10 minutes and the t1/2 of the first exponential. Emptying of the gall bladder was faster and more of its contents were ejected in subjects with a type I response (n = 9) than in subjects with a type II response (n = 6). In the remaining seven subjects the gall bladder began to empty spontaneously, unrelated to eating. These observations suggest that gall bladder emptying: (a) may have a cephalic phase, (b) can be expressed as a double exponential function, (c) may occur unrelated to eating, (d) which occurs only in relation to eating would appear to be either fast (type I) or slow (type II).

Behavioral effects of vagotomy in humans

Animal experiments and clinical observations have demonstrated significant effects of vagotomy on body weight. Weight loss or inability to regain are partly due to impaired motility and secretomotor activity of the vagus nerve causing disturbances in digestion which, however, are not sufficient to explain most of the weight deficit after vagotomy in animals or morbidly obese patients. The body weight deficit is also due to reduced caloric intake with changes in the quantity and quality of food and liquid intake, the latter accounting for more than one-third of the total reduction in caloric intake. Obese patients have consistent decreases in hunger ratings after vagotomy and also reveal changed hedonic ratings and estimations of taste intensity. Validation of vagotomy studies requires tests of vagal integrity to confirm the completeness of the surgery and rule out regeneration of nerve tissue or recruitment of function. Tests of completeness of vagotomy are difficult to perform and evaluate in morbidly obese patients due to insulin resistance. The finding of an inadequate gastric acid response to insulin hypoglycemia implies a defect hypothalamic response to hypoglycemic stress in these patients. A new postoperative test of completeness of vagotomy based on disrupted drinking after intravenous hypertonic saline challenge is introduced as an attractive alternative to the potentially hazardous insulin test.

Effect of highly selective vagotomy on pancreatic exocrine function and on cholecystokinin and gastrin release

The effect of highly selective vagotomy on pancreatic exocrine function and the release of gastrin and cholecystokinin was studied in 10 patients with endoscopically-proven duodenal ulceration. Cholecystokinin and gastrin concentrations in serum both increased significantly after highly selective vagotomy. Amylase concentration in the duodenal aspirate increased significantly after vagotomy, but trypsin concentration remained unchanged. The expected reductions in gastric acid secretion were noted. Thus highly selective vagotomy reduces acid secretion effectively in patients with duodenal ulcer without impairing the exocrine function of the pancreas.

Estimation of 14C-triolein assimilation as a test of lipid assimilation. Breath test or measurement of serum radioactivity?

Two tests of lipid assimilation based on estimation of 14C-triolein assimilation from expiratory 14CO2 (breath test) and from serum radioactivity of 14C, respectively, were investigated in 48 consecutive patients suspected of having malassimilation. Patients with proven malassimilation had significantly lower expiration of 14CO2 and lower serum radioactivity of 14C than patients with normal lipid assimilation. The se-14C test correctly diagnosed significantly more patients with malassimilation than the breath test; the diagnostic efficiencies were 0.87 and 0.74, respectively. The results of both tests correlated with measurement of faecal fat. However, within the group of patients with proven malassimilation the results of the breath test correlated poorly with faecal fat, whereas a significant correlation was found between the se-14C test and faecal fat within this group. Correspondingly, the correlation between the results of the breath test and the se-14C test was poor, indicating that intermediate metabolism influences the results.

Effect of vagotomy on exocrine pancreatic and biliary secretion in man

The exocrine pancreatic and biliary secretion in response to vagal stimulation by insulin hypoglycemia was measured in preoperative patients with duodenal ulcer and in patients who underwent highly selective vagotomy, bilateral selective vagotomy with pyloroplasty, and truncal vagotomy with pyloroplasty. Significant stimulation of both biliary and pancreatic secretion occurred only in patients with an intact vagal nerve supply. No evidence of increased lithogenicity of human bile was found up to 2 years after truncal vagotomy.

An interim report on parietal cell vagotomy versus selective vagotomy and antrectomy for treatment of duodenal ulcer

This is an interim report of a prospective, randomized study involving 194 consecutive patients who underwent elective operation for treatment of duodenal ulcer. The results of parietal cell vagotomy without drainage (PCV) and selective vagotomy-antrectomy and Billroth I anastomosis (SV-A-B I) were compared. There was no mortality. Postoperatively patients were examined at two, six, 12 months and every 12 months thereafter. The two operations showed no statistical difference in the frequency of diarrhea. Dumping was less (p < .01) after PCV than after SV-A-B I. Weight loss was less (p < .01) after PCV than after SV-A-B I. There were no recurrent ulcers after SV-A-B I and five after PCV. In each instance but one the recurrent ulcer healed on withdrawal of an ulcerogenic drug. One patient required reoperation. Reoperations in the PCV group consisted of one for recurrent ulcer, one for gastric outlet obstruction and three for intestinal obstruction. The reoperations after SV-A-B I consisted of four for gastric outlet obstruction, three for intestinal obstruction, one for ruptured spleen and two for incisional hernia. PCV was technically feasible and practical to perform except in the occasional patient with severe pyloric stenosis. Obesity was never a deterrent. After PCV it is reasonable to assume that a recurrent ulcer rate in the range of 5-10% can be expected by surgeons who have been properly trained. This recurrence rate is higher than that after SV-A-B I but no higher than that encountered with TV-P. The recurrence rate is acceptable and is a fair exchange for the avoidance of dumping and weight loss that accompany SV-A-B I with significantly greater frequency and which on occasion can produce gastric crippling, although this did not occur in this study. All recurrent ulcers after PCV do not require reoperation but when operative treatment is required the patient has all the options that he had prior to PCV.

Vagotomy for treatment of severe obesity

Three women weighing 137, 133, and 135 kg underwent truncal vagotomy; after 16, 20, and 24 weeks they had lost 10, 17, and 19 kg respectively without serious side-effects. No dietary restrictions have been imposed, but they are eating less than they were preoperatively and report a total lack of hunger. Truncal vagotomy may be a useful treatment for severe obesity.

Geographical aspects of peptic ulcer surgery

The geographic distribution of duodenal ulcer and its characteristics in rural areas of high incidence in developing countries are reviewed. The choice of surgical procedures is discussed in light of the bulky diet and nutritional problems of these countries. A vagotomy procedure is advised for duodenal ulcer and a Billroth I gastrectomy for gastric ulcers of the body of the stomach.

The functional state of the gastrointestinal tract after ulcer surgery. A ten-year prospective follow-up study

Of 35 patients operated upon for peptic ulcer and subjected to absorption tests before operation, 26 could be followed up with absorption tests for 1, 6, and 10 years after operation. The following operations had been performed on the latter: antrectomy with gastroduodenostomy in 10, antrectomy with selective vagotomy and gastroduodenostomy in 9, and other operations in 7. None had recurrence of the ulcer or disturbing abdominal complaints during the follow-up period. Ten years after operation there was an increase in the mean value of the Schilling test, and all patients had a normal serum B12 vitamin level. On the other hand, a decrease was noticed in the mean value of the d-xylose test and an increase in that of faecal dry-weight fat content. At the time of the 10th year follow-up examination, 6 patients had an impaired d-xylose absorption and 7 an impaired fat absorption. According to the increase in the mean body weight and the serum protein and haemoglobin concentration, the nutritional status had not worsened.