Distribution of a liquid meal within the stomach and gastric emptying after vagotomy and drainage operations.

The intragastric distribution of a radionuclide labelled liquid meal was studied in 62 patients with duodenal ulceration by means of a gamma camera imaging system. A total of 85 gastric emptying studies (23 preoperative and 62 postvagotomy tests) revealed three distinct patterns of distribution. The activity distribution in the stomach after vagotomy showed a slower rate of return and a decreased accumulation of the meal in the proximal part of the stomach compared with the pattern in the intact stomach. The return of the liquid meal to the proximal stomach was considered to be a physiological process controlled by vagal reflexes and changed by a vagotomy. These observations made during emptying of a liquid meal seem to give rise to a better differentiation of the motor patterns after various types of gastric operations. With a quantification of the intragastric patterns of distribution it may be possible in a prospective study to give a more graded evaluation of changes induced by vagotomy than is possible with the traditional characterisation of gastric emptying.     

Progression of changes in gastric emptying of hypertonic liquids after proximal gastric vagotomy

Gastric emptying rates of hypertonic (10%) dextrose liquid meals were studied in five dogs before, and 3, 6, and 12 months after proximal gastric vagotomy (PGV) without drainage. The purpose of this study was to determine if operation-related changes in emptying rates normalized or became more disparate during the year after PGV. An increased rate of emptying during the first 5 min after ingestion was seen at 3 months after PGV, which significantly increased (P<0.025) after 6 and 12 months. The remainder of the meal after PGV emptied at a regulated exponential rate unchanged throughout the postoperative year from its preoperative rate. Total volumes of gastric aspirate at four intervals after meal ingestion did not significantly change across the four test periods in respect to endogenous secretion or pH acidity.Supported by The Veterans Administration.     

Gastric emptying in control subjects and patients with duodenal ulcer before and after vagotomy.

The emptying of a solid meal labelled with Indium 113mDTPA from the stomach was studied with a gamma camera in 26 normal subjects, 27 patients with duodenal ulcer, on 41 occasions after truncal vagotomy and pyloroplasty and 38 times after highly selective vagotomy. Applying the method of principal component analysis to the results, differences were detected between control and duodenal ulcer subjects and two probable subgroups of duodenal ulcer were observed. Half emptying times did not reveal these patterns. After vagotomy, delayed emptying was general at one week. At one month, patients after highly selective vagotomy had a more normal result than those with truncal vagotomy and pyloroplasty (TV), but by six months no significant difference in overall emptying rate was found, although changes in the pattern of gastric emptying persisted in some patients after TV.     

Gastric motility and emptying in normal and post-vagotomy subjects.

The effects of proximal gastric vagotomy (PGV) and vagotomy with pyloroplasty (V and P) on gastric motility were studied using a solid meal labelled with a radiopharmaceutical agent. In having on-line computer facilities it was possible not only to record the rate of emptying but also to analyse the relative roles of the fundus and the antrum within the overall framework of gastric emptying. In normal subjects the fundus filled and then emptied in an almost linear pattern. The antrum, however, did not completely fill until well after the meal was eaten and thereafter appeared to maintain a constant volume during the study. The redistribution of contents between fundus and antrum was reflected in the total stomach emptying curve as a delay, or lag phase before gastric emptying commenced. After both types of vagotomy fundic filling was delayed, representing a slower eating time, which was presumably due to early satiety. Antral filling and volume was disturbed only after V and P, which was also reflected by a loss of the lag phase seen on the total stomach curve. PGV retained antral function but there was significant delay in the redistribution of contents between fundus and antrum, though this did not have clinical significance. The rate of emptying was unaffected by either operation. It was concluded PGV did maintain antral function and a more normal pattern of emptying compared with V and P. After V and P the changes in antral function were considerable and these changes are probably associated with some of the complications resulting from this operation.     

Gastric emptying after treatment of stenosis secondary to duodenal ulceration by proximal gastric vagotomy and duodenoplasty or pyloric dilatation.

A consecutive series of 12 patients with stenosis secondary to duodenal ulceration were treated by proximal gastric vagotomy (PGV) and duodenoplasty or PGV and dilatation of the stenosis. Three months after operation the rate and pattern of gastric emptying of a solid meal was measured in each patient and compared with 18 patients with uncomplicated duodenal ulcer treated by PGV alone. Two patients developed gastric stasis in the early postoperative period which resolved with medical treatment. All patients were asymptomatic and were eating normally three months after operation. There was no significant difference in the rate of gastric emptying postoperatively between the patients who had stenosis and those who had uncomplicated duodenal ulcers. These results indicate that despite early postoperative difficulties in some patients pyloric dilatation or duodenoplasty with PGV are both effective treatments for stenosis due to duodenal ulceration.     

Abnormal gastric myoelectrical activity and delayed gastric emptying in patients with symptoms suggestive of gastroparesis

Gastric myoelectrical activity modulates gastric motor activity. Abnormalities in gastric myoelectrical activity may be associated with gastric motility disorders. The aim of this study was to investigate the correlation of gastric myoelectrical activity with gastric emptying in symptomatic patients with and without gastroparesis. Ninety-seven patients with symptoms suggestive of gastroparesis participated in the study. Gastric myoelectrical activity was recorded using surface electrogastrography. The electrogastrogram (EGG) was recorded for 30 min in the fasting state and for 120 min after a solid test meal. Gastric emptying of the solid meal was simultaneously monitored for 120 min. Patients with delayed gastric emptying showed a significantly lower percentage of normal gastric slow waves (P<0.03) and a significantly reduced increase of the dominant power in the postprandial EGG (P<0.02). Postprandial EGG parameters were found to be able to predict delayed emptying of the stomach. Postprandial gastric dysrhythmia predicts delayed gastric emptying with an accuracy of 78%, while the abnormality in postprandial EGG power predicts delayed gastric emptying with an accuracy of 75%. All patients with abnormalities in both the rhythmicity and the power had delayed gastric emptying. Patients with delayed gastric emptying have a lower percentage of normal gastric slow waves in the EGG and a lower postprandial increase in the dominant power. Abnormalities in the postprandial EGG seem to be able to predict delayed emptying of the stomach. However, a normal EGG does not seem to guarantee normal emptying of the stomach.     

The effect of preserving antral innervation and of a pyloroplasty on gastric emptying after vagotomy in man

A prospective randomized trial of 40 duodenal ulcer patients is reviewed. The patients had one of four operations (selective vagotomy, proximal gastric vagotomy, selective vagotomy plus pyloroplasty, or proximal gastric vagotomy plus pyloroplasty). The gastric emptying of a hypertonic fluid meal was assessed before and three to four months after operation. Selective vagotomy without a drainage procedure results in gastric retention and should no longer be considered as a method of treatment for duodenal ulcer. Proximal gastric vagotomy without a drainage procedure does not lead to gastric retention. Initial gastric emptying is more rapid after proximal gastric vagotomy but the final emptying time is the same as before operation and this operation alters the pattern of gastric emptying less than the other operations. Pyloroplasty added to either selective or proximal gastric vagotomy results in loss of the normal regulation of gastric emptying, very rapid initial gastric emptying, and a significant increase in the incidence of ;dumping'. It appears from these studies that ;dumping' is due to rapid gastric emptying and mainly due to the drainage procedure.     

Effect of vagotomy on biliary-tract motor activity in the opossum

In this study, we evaluated the effect of truncal vagotomy in the opossum on changes in gallbladder and sphincter-of-Oddi (SO) contractile activity that occur normally during fasting and after a meal. In six animals, bipolar electrodes were implanted on the SO gastric antrum, duodenum, and jejunum. A catheter secured in the gallbladder fundus was used to monitor gallbladder volume. After control studies, truncal vagotomy and pyloroplasty were done in each animal. Before vagotomy, the SO exhibited cyclic changes in spike-burst rate, from 2 to 5/min, that were synchronized with corresponding phases of the duodenal MMC cycle. The gallbladder exhibited partial emptying during the second half of the duodenal MMC cycle with refilling during the first half of the next cycle. By two weeks after vagotomy, the MMC-related changes in SO and gallbladder contractile activity were normal. In contrast, vagotomy retarded the increase in SO spike-burst rate and delayed as well as diminished the pronounced gallbladder emptying that normally occurs after a meal. The same effects were observed for changes in SO and gallbladder activity induced by intraduodenal infusion of Isocal. After vagotomy, the SO and gallbladder exhibited exaggerated responses to intravenous infusion of CCK-OP or motilin. We conclude that truncal vagotomy in the opossum does not affect the fasting pattern of SO and gallbladder contractile activity, but it significantly alters the normal postprandial pattern of enhanced SO spike-burst rate and pronounced gallbladder emptying. The precise mechanism(s) whereby vagotomy produces these changes remains to be determined.This work was supported, in part, by National Institutes of Health grant AM 25731.This work was abstracted, in part, inGastroenterology 86:1273, 1984.     

Pancreaic polypeptide

The pancreatic polypeptide (PP) response to food has been measured by radioimmunoassay in patients with duodenal ulcer and 3 months following proximal gastric vagotomy (PGV), 18 and 49 months following truncal vagotomy and pyloroplasty (TV), 35 months following Billroth II gastrectomy (BII), and 35 months following truncal vagotomy and antrectomy (TV&A). Basal PP levels and those in response to food were similar in DU and PGV, but these values were significantly higher than those 18 months or 49 months after TV, or after BII and TV&A. The responses in the latter four groups were similar and in particular, the levels 18 and 49 months after TV were the same. These results indicate that the release of PP by food in unoperated patients consists of two phases, a primary phase which requires both intact vagi and an intact stomach and a secondary phase which also depends on vagal innervation and normal gastric anatomy. Disturbances in vagal innervation or gastric integrity lead to profound changes in PP release which may be due to interruption of neural arcs or loss of gastric hormones. Unlike others, we have been unable to document a return of PP secretion towards normality with time after TV.     

The vagus, the duodenal brake, and gastric emptying.

It has been suggested that an intact vagal supply is essential for the normal function of the recptors in the duodenum and proximal small bowel, which influence the rate of gastric emptying. This paper reports the effect of vagal denervation on gastric emptying and also examines the site and mode of action of receptors in the proximal small bowel.It has been demonstrated in the dog that most, if not all, the receptors controlling gastric emptying lie in the proximal 50 cm of the small bowel. Following truncal vagotomy the emptying time of each instillation increased significantly and the differential rate of emptying of different instillations remained unchanged. The proximal 50 cm of small bowel was capable to differentiating between different instillates even after selective extragastric vagotomy, in which the duodenum was vagally denervated and, therefore, duodenal braking receptors function independently of vagal innervation.     

Effect of highly selective vagotomy on gastric motor activity of duodenal ulcer patients

The effect of highly selective vagotomy on the gastric emptying time of a food-barium meal and antral myoelectrical and manometrical activities was studied in two groups of duodenal ulcer patients: one with and another without delay in gastric emptying. Controls performed 1 and 3 months after operation showed that the group of patients with non-delayed preoperative gastric emptying kept a good emptying, only with sporadic, slight and transient disturbances of the gastric myoelectric activity. Conversely, the group of patients with delayed preoperative gastric emptying showed an increase in emptying time together with marked alterations in myoelectric and manometric activities.     

Effects of highly selective vagotomy on gastric myoelectrical activity

Changes in gastric myoelectrical activity following highly selective vagotomy were studied in 12 patients by means of electrogastrography (EGG) using cutaneous electrodes. Measurements were made before, 10 days after, and six months after operation. Eight patients undergoing cholecystectomy served as controls. Preoperatively all controls and patients had normal recordings. In the cholecystectomized patients no significant changes were found postoperatively. Ten days after highly selective vagotomy the normal initial postprandial dip in gastric ECA frequency and the subsequent increase in frequency and power were not seen. Tachygastrias were observed in three patients. Six months after operation the normal frequency and power responses to a test meal had returned, but both the fasting and postprandial ECA frequencies were raised significantly. It is concluded that highly selective vagotomy is associated with abnormalities in myoelectrical activity, in particular in the postprandial state, most of which are reversible with time.     

The effect of parietal cell vagotomy and selective vagotomy with pyloroplasty on gastric emptying of a solid meal. A prospective randomized study.

A new technique is described whereby gastric emptying of a 51Cr-labelled solid meal (hamburger, vegetables, potatoes) was measured by way of a movable NaJ(T1) detector. The technique allowed separate measurements over the proximal and the distal part of the stomach. Seven volunteers took part in a study which revealed good correlation between two individual consecutive tests. Eight patients who took part in a controlled randomized series of parietal cell vagotomy (PCV) versus total gastric selective vagotomy and pyloroplasty (SV+P) underwent the test preoperatively and 6 to 8 months postoperatively. Following both operations gastric emptying was retarded. The time taken for the amount of meal remaining in the stomach to be reduced to 75,50 and 25% respectively was significantly longer postoperatively than before surgery, but there were no differences in this respect between PCV and SV+P. The retardation of gastric emptying of solids was in contrast to the emptying of 10% glucose solution, which in the same series of patients was found to be accelerated. Following PCV there was a change in the distribution of the meal within the stomach immediately after the intake of the meal: a larger part of the meal was found in the proximal stomach post-operatively than before operation. There was no significant change in this intragastric distribution of the meal after SV+P.     

Gastric emptying following Finney pyloroplasty and vagotomy

Gastric emptying was evaluated in a series of unanesthetized dogs in the intact state, following Finney pyloroplasty, and with the addition of vagotomy. Sodium chromate labeled test meals of glucose, trisodium citrate, and trisodium citrate-fat were used. Finney pyloroplasty resulted in a trend for delayed emptying of fat from the stomach. The trisodium citrate test meal increased the levels of gastric secretion after pyloroplasty.Association of our previous motility data based on pyloroplasty studies with the current gastric-emptying evaluations indicate that too large a stoma between the antrum and duodenum is an impediment to normal gastric emptying of fatty meals.The authors appreciate the technical assistance of Mr. James E. Copp, Department of Biostatics, Parke, Davis Research Labs.     

Gastric emptying following vagotomy and antrectomy and proximal gastric vagotomy.

Gastric emptying of solid meals labelled with 129Cs was studied in patients for up to one year after vagotomy and antrectomy or after proximal gastric vagotomy. Significant delay was found one month after vagotomy and antrectomy but this had returned to normal by six months. No delay was found after proximal gastric vagotomy. The effect of posture on gastric emptying was also studied in the same subjects. No significant differences were found between gastric emptying in the supine or sitting positions after solid meals.     

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.     

The effects of varying the extent of the vagotomy on the myoelectrical and motor activity of the stomach

The effects of varying the extent of vagotomy on the myoelectrical and motor activity of the stomach have been successfully studied in 21 patients undergoing either truncal, selective, or highly selective vagotomy for the treatment of chronic duodenal ulceration. The mean percentage time that regular antral myoelectrical activity was recorded preoperatively was 95.8% +/- 1.0 and this was decreased following highly selective vagotomy (74.0% +/- 6.6), selective vagotomy (37.8% +/- 12.4), and truncal vagotomy (30.2% +/- 10.4). The mean amplitude of the pacesetter potential was less following truncal (0.86 mV +/- 0.05), selective (1.32 mV +/- 0.09), and highly selective vagotomy (1.67 +/- 0.09) than in preoperative studies (2.21 mV +/- 0.12). Following truncal and selective vagotomies the triphasic waveform of the pacesetter potential changed to a sinusoidal shape. No significant change in the mean preoperative frequency of the myoelectrical activity (3.03 cpm +/- 0.08) occurred after vagotomy. Thus the changes in the electrical activity of the stomach are related to the extent of the vagal denervation. Intravenous administration of insulin did not alter these patterns except after highly selective vagotomy when the amplitude of the electrical waves, the incidence of action potentials, and percentage motor activity were increased.     

Gastric emptying for solids in patients with duodenal ulcer before and after highly selective vagotomy

In a series of 31 duodenal ulcer patients (23 males and 8 females), who underwent a highly selective vagotomy, gastric emptying characteristics of a solid meal, labeled with [su99mTc]stannous colloid, were assessed before, two weeks and six months after operation. The clinical diagnosis was confirmed by endoscopy and x-ray; failure of treatment with H₂ antagonists or antacids during 1–18 (mean 5) years was the direct indication for operative treatment. A temporary delay in gastric emptying is noted two weeks after operation (T 1/2: 124 vs 57 min). After six months, gastric emptying time has practically normalized. It appears that this is the result of the preservation of the antropyloric vagal nerve supply. In these patients, a 10% recurrence rate is noted, comparable to the results in the literature. Highly selective vagotomy proves to be a safe and effective procedure with few side effects. It does not impair gastric motility.     

Supersensitivity and gastric emptying after vagotomy

Investigations were carried out in man and dog to study the validity of Cannon's law of denervation supersensitivity in relation to parasympathetic denervation of the stomach. Subthreshold doses of carbachol did not accelerate gastric emptying before vagotomy but caused a significant increase in the rate of gastric emptying after vagotomy. These findings may be relevant to aberrations of gastrointestinal motility after vagotomy and may provide the basis of a test for completeness of gastric vagotomy.     

Relative role of pyloroplasty size,truncal vagotomy,and milk meal volume in canine gastric emptying

The gastric emptying of 10, 20, or 40 ml/kg body mass milk meals was measured before and after Heineke-Mikulicz pyloroplasty of 3, 5, or 7 cm (6 dogs) or truncal vagotomy (3 dogs). The pyloroplasty group then underwent vagotomy, following which the tests were repeated. Initial gastric emptying (in the first 10 min) was increased after 5-and 7-cm pyloroplasties (P<0.01) and particularly after vagotomy with all sizes of pyloroplasty (P=0.001). Regardless of the volume of meal used, after vagotomy and pyloroplasty there was a 51–63% decrease in intragastric volume within the first 10 min. Increased duodenogastric reflux occurred in those dogs who showed rapid initial gastric emptying. After the first 10 min all groups were shown to have virtually normal gastric emptying, except the truncal vagotomy group in which gastric emptying was delayed (P<0.05). It is the combination of pyloroplasty with vagotomy which is required to produce the very rapid initial gastric emptying of a liquid meal following vagotomy with pyloroplasty. It is concluded that two mechanisms control the gastric emptying of a milk meal. The first acts quickly, is dependent on an intact pylorus, and is influenced by the intragastric volume; the second is a more slowly acting mechanism, requiring up to 10 min to have its effect, and is not dependent on an intact pylorus or the intragastric volume. After vagotomy and pyloroplasty, the speed of gastric emptying in the first 10 min is proportional to the original meal volume, and therefore the therapy of postvagotomy diarrhea and dumping with small frequent meals seems rational.This report is based on a PhD (Med) thesis presented to the University of the Witwatersrand, Johannesburg.This work was funded by the University of the Witwatersrand, Miller Foundation and Medical Research Council of South Africa.