Effect of cisapride on gallbladder emptying and plasma CCK in normal and vagotomized human subjects

Simultaneous/Incidental cholecystectomy during gastric/esophageal resection: systematic analysis of risks and benefits

BACKGROUND

After esophageal/gastric resection with resulting truncal vagotomy, the incidence of gallstone formation seems to increase. The clinical relevance of gallstones and the role of simultaneous/incidental cholecystectomy in this setting are controversially discussed.

METHODS

Systematic analysis has been performed for retrospective/prospective studies on the incidence/symptoms of gallstone formation after esophageal/gastric resection. Pooled estimates of the incidence of cholecystectomies were calculated by random effect models. Risk analyses of simultaneous, acute postoperative cholecystectomy and long-term cholecystectomy were performed.

RESULTS

Sixteen studies on gallstone formation after upper gastrointestinal (GI) surgery (3,735 patients) reported increased incidences of 5-60% with a pooled estimate of 17.5% (95% confidence interval (CI), 14.1-21.2%; inconsistency statistic (I (2)) = 86%) compared with 4-12% in the control population. In 113 of 3,011 patients (12 studies), late cholecystectomies were performed for symptomatic cholecystolithiasis, corresponding to an estimated overall proportion of 4.7% (95% CI, 2.1-8.2%; I (2) = 92%). In 1.2% (95% CI, >0-3.7%; I (2) = 93%) of patients undergoing upper GI surgery, a cholecystectomy was performed because of acute postoperative biliary problems (4 studies, 8,748 patients). Simultaneous cholecystectomy had a higher morbidity of 0.95% (95% CI, 0.54-1.49%; I (2) = 28%) compared with the calculated additional morbidity of early and late cholecystectomy of 0.45%.

CONCLUSIONS

Approximately 6% of patients undergoing upper GI surgery are expected to require cholecystectomy during follow-up. Because late cholecystectomies can be performed safely and because the additional calculated morbidity for these operations is lower than the morbidity for simultaneous cholecystectomy, it cannot generally be recommended to remove a normal acalculous gallbladder during upper GI surgery.

Gall bladder emptying in patients with corrosive-induced esophageal strictures

Ingestion of corrosive substances can lead to strictures of the esophagus and stomach. Cicatrization of the lower part of the esophagus can entrap vagal fibers in the process of fibrosis. The aim of the present study was to evaluate gallbladder dysfunction as a sequel to vagal damage in patients with corrosive-induced esophageal strictures. The cephalic phase of gallbladder emptying was stimulated by modified sham feeding according to the chew-and-spit method. Gallbladder volume was measured by ultrasonography using the ellipsoid method after an overnight fast and every 15 min for a period of 90 min after sham feeding in 22 patients and 10 controls. Mean fasting gallbladder volume was significantly greater in patients than in controls (22.09 +/- 9.78 vs. 14.61 +/- 4.42 ml; P = 0.025). After sham feeding the gallbladder ejection fraction was significantly lower in patients than in controls (32.86 +/- 17.21 vs. 49.40 +/- 7.86%; P = 0.007). Patients with cicatrization in the distal one-third of the esophagus had a greater basal gallbladder volume (24.57 +/- 9.2 ml) and significantly lower ejection fraction (20.47 +/- 8.9%) than patients with strictures at other sites (gallbladder volume, 18.50 +/- 10.69 ml; ejection fraction, 47.48 +/- 13.3%; P = 0.001). In conclusion, patients with corrosive-induced esophageal strictures, especially those in the distal one-third, had an increased fasting gallbladder volume and decreased cephalic phase of gallbladder emptying, pointing to impaired vagal cholinergic transmission, possibly due to vagal entrapment in the cicatrization process.

Tegaserod does not alter fasting or meal-induced biliary tract motility

OBJECTIVE

Tegaserod is a 5-HT(4) receptor partial agonist that increases peristaltic activity of the intestinal tract. It is approved for the treatment of patients with irritable bowel syndrome with constipation (IBS-C). IBS is a chronic gastrointestinal disorder of function that is reported to be associated with an increased incidence of abdominal surgery including cholecystectomy. The effect of tegaserod on nongut digestive organs, such as the gallbladder and biliary tract, has not been previously investigated. Therefore, this study aimed to evaluate the effects of tegaserod on gallbladder contractility and on functional status of the sphincter of Oddi during both the interdigestive and the digestive periods in healthy female subjects and in female patients with IBS-C.

METHODS

During a 6-wk, double-blind, placebo-controlled crossover study, gallbladder contractility and concomitant change in luminal diameter of the common hepatic duct (CHD) and the common bile duct (CBD, both proximal and distal) in response to a standard liquid meal were quantified using real-time ultrasonography. Changes in luminal diameter of the CHD and the CBD were used as a surrogate marker for sphincter of Oddi function. Ultrasound measurements were conducted every 15 min from 45 min before, to 60 min after the test meal to observe the impact of tegaserod on gallbladder volume and any concomitant change in the diameters of the CHD and the CBD that developed in response to gallbladder contraction. The ultrasound measurements of gallbladder contractility, along with the CHD and the CBD diameters, were repeated after each of the two 2-wk periods of treatment with tegaserod or placebo. The recommended dose of tegaserod (6 mg b.i.d.) for IBS-C patients was used in healthy female subjects (n = 13) and female patients with IBS-C (n = 20). Twice this dose (12 mg b.i.d.) was also evaluated in an additional 20 female patients with IBS-C. Statistical evaluations were conducted using a two-sided analysis of variance (ANOVA).

RESULTS

Gallbladder contractility variables including ejection fraction, ejection rate and ejection period, fasting and residual volume, and maximal emptying, were similar after 2 wk of treatment with tegaserod 6 mg b.i.d. and placebo in healthy female subjects and female patients with IBS-C. There were no significant changes in the luminal diameters of the CHD or the CBD after tegaserod compared to placebo in any cohort. Additionally, no significant dilation (> or =7 mm in diameter) of the CHD or CBD was observed during maximal gallbladder emptying. Similar results were also observed when tegaserod was given at 12 mg b.i.d. in patients with IBS-C. Tegaserod treatment had no significant effect on plasma CCK concentration in response to the test meal. No significant abdominal pain or unexpected adverse events were reported during the study.

CONCLUSIONS

This study showed no significant pharmacodynamic effect of tegaserod on gallbladder contractility or on CBD and CHD diameters as a surrogate marker of sphincter of Oddi function during both the interdigestive (fasting) and the digestive (postprandial) periods in healthy female subjects and female patients with IBS-C.

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The effect of cholecystectomy on plasma cholecystokinin

OBJECTIVE

Gallbladder removal is associated with an increased incidence of gastroesophageal reflux, but the mechanism is unclear. Cholecystokinin (CCK) release, which causes gallbladder contraction, is inhibited by bile in the duodenum. This study investigates the effect of cholecystectomy on meal-stimulated CCK secretion.

METHODS

Three groups of patients were studied. Group 1 (n = 15) were normal controls. Group 2 (n = 27) were patients with symptomatic gallstones. Group 3 (n = 25) were patients who had undergone cholecystectomy. Meal-stimulated CCK levels were measured by radioimmunoassay at defined time points for 60 min after a standard corn oil-based meal.

RESULTS

Fasting CCK levels were similar in all three groups. In postcholecystectomy patients, meal-stimulated plasma CCK levels were significantly elevated compared with controls: median (range) integrated CCK values for 60 min were 116 (28-209) in controls, 123 (20-501) in gallstone patients, and 176 (63-502) after cholecystectomy.

CONCLUSIONS

This study suggests that cholecystectomy causes an exaggerated meal-stimulated CCK response. Because CCK is known to relax the lower esophageal sphincter. these findings may help explain the increased incidence of gastroesophageal reflux seen after cholecystectomy.

Biliary Tract Dysmotility

Biliary pain resulting from motility disorders is common and may be overlooked due to the difficulty of diagnosing the presence of these disorders. A sound, logical approach to the evaluation and treatment of these specific groups of disorders is essential. In patients who have a gallbladder, we initially exclude the presence of gallstones by use of transcutaneous ultrasonography. If a patient's symptoms are atypical, we initiate therapy (eg, antispasmodics) for irritable bowel syndrome. Subsequently, we perform a quantitative cholescintigraphy with a low-dose infusion of cholecystokinin in patients with typical symptoms and in those with persistent atypical symptoms. Those patients who have abnormally low gallbladder ejection fractions are subsequently referred for laparoscopic cholecystectomy. In postcholecystectomy patients, a standard approach should include obtaining serum liver associated laboratory chemistries, amylase and lipase levels, and a transcutaneous ultrasound to measure bile duct size. Endoscopic retrograde cholangiopancreatography (ERCP) is done to measure bile duct size, assess biliary duct emptying, and exclude other etiologies for pain. In patients with more than two abnormal findings on these tests (type I sphincter of Oddi dyskinesia), we recommend performing an empiric endoscopic biliary sphincterotomy. In patients with no objective abnormalities (type III sphincter of Oddi dyskinesia), it is appropriate to begin medical therapy with antispasmodics and calcium-channel antagonists. In individuals who have one or two abnormalities (type II sphincter of Oddi dyskinesia) we prefer endoscopic biliary sphincterotomy; however, these individuals are offered the opportunity to have endoscopic biliary manometry performed in order to establish a clear diagnosis. If patients refuse this procedure, after careful explanation of risks, alternatives, and possible benefits of the procedure, empiric endoscopic biliary sphincterotomy is performed.

Effect of cisapride on the isolated guinea pig gall bladder and common bile duct

1. In this study, the effect of cisapride on the isolated guinea pig gall bladder (GB) and common bile duct (CBD) motility was investigated. 2. Cisapride, up to a certain concentration, produced an increase in tone of the GB (EC50 1.35 x 10(-8) M) and the CBD (EC50 2.75 x 10(-9) M), whereas, at concentrations higher than 3 x 10(-5) M for the GB and 5 x 10(-6) M for the CBD, it produced a transient increase in tone followed by a sustained decrease in tone or in the contraction amplitude or in both. 3. The cisapride-induced increase in tone was antagonized by atropine on both the GB and the CBD. 4. Cisapride up to 2 x 10(-5) M for the GB and 3 x 10(-6) M for the CBD did not modify, whereas, at concentrations higher than 2.8 x 10(-5) M for the GB and 4 x 10(-6) M for the CBD, it antagonized, noncompetitively, the concentration-response curve to exogenously applied acetylcholine. The IC50 values for cisapride on the EC50 of acetylcholine on the GB and the CBD were 9.4 x 10(-5) M and 8.2 x 10(-6) M, respectively. 5. In conclusion, on the guinea pig GB and CBD, low concentrations of cisapride produce a stimulating effect, probably of cholinergic origin, whereas higher concentrations produce a transient stimulating effect, probably of cholinergic origin, followed by a sustained relaxing effect, which may involve both cholinergic and noncholinergic pathways.