Bile composition and bile acid pool size. Comparison after truncal, selective, and highly selective vagotomy

Changes in gallbladder motility in gastrectomized patients

OBJECTIVES

Gastric resection may predispose gallstone formation. However, the mechanism has not been clearly understood. To evaluate the relationship between gastric resection and gallstone formation, we compared gallbladder(GB) motility in gastrectomized patients and control subjects.

METHODS

We compared the GB volume and ejection fraction of the 46 gastrectomized patients with 37 healthy controls using real time ultrasonography.

RESULTS

GB volume increased significantly in the gastrectomized group in fasting (30.2 +/- 13.9 ml). The GB volume after a fatty meal was greater in the gastrectomized group (12.6 +/- 6.4 ml) than in the control group (4.3 +/- 3.3 ml) (p < 0.01). A significant reduction of ejection fraction was found in gastrectomized patients (56.9 +/- 13.0%) in comparison with the control group (75.5 +/- 16.1%) (p < 0.01). The GB ejection fraction had a poor correlation to the postoperative period (r = 0.232).

CONCLUSION

A gastrectomy appears to be a risk factor of GB dysmotility, which may play a major role in gallstone formation in gastrectomized patients.

Gallbladder motility, gallstones, and the surgeon

Cholecystectomy is one of the commonest surgical procedures in the Western world, with more than half a million procedures performed annually in the United States alone. In recent years, studies of gallstone pathogenesis and gallbladder disease have increasingly focused on abnormal gallbladder motility in the pathogenesis of some, if not all, gallbladder conditions. The control of gallbladder motility is complex and depends on an intricate interplay of neural and hormonal factors. An understanding of the control of gallbladder motility is crucial to the understanding of the mechanisms of gallstone formation and may help to explain the failure to cure symptoms after cholecystectomy in up to one third of patients. The purpose of this article is to outline mechanisms controlling gallbladder motility, examine recent developments in our understanding of this complex process, and relate changes in motility to common disease conditions of the gallbladder. The role of altered motility in the pathogenesis of gallstones is discussed and the effects of commonly performed surgical procedures such as truncal vagotomy and cholecystectomy on upper gut physiology are reviewed.

Cholelithiasis and bile acid absorption after truncal vagotomy and gastroenterostomy

Gallbladder disease in the form of gallstones demonstrated by ultrasonography or previous cholecystectomy was found in 15 of 26 women of median age 69 (range 52-82) years who had had truncal vagotomy and gastroenterostomy performed a median of 27 (range 11-30) years previously, compared with eight of 31 healthy age- and sex-matched controls drawn from the community (P < 0.02). Bile acid malabsorption identified by retention of 23-selena, 25-homotaurocholate (75SeHCAT) occurred in only two of the 26 patients after vagotomy and there was no relationship between retention and the presence or absence of gallbladder disease. The serum concentration of 7 alpha-hydroxycholestenone, an indicator of bile acid turnover, was significantly lower in patients with gallbladder disease after vagotomy than in controls (mean(s.e.m.) 19.1(3.7) versus 31.4(4.4) ng/ml, P < 0.05). Bile acid malabsorption does not play a significant role in the pathogenesis of gallstones after vagotomy but decreased bile acid synthesis may be important. There is no correlation between retention of 75SeHCAT and 7 alpha-hydroxycholestenone levels in patients after vagotomy, indicating that bile acid synthesis and absorption are uncoupled in this situation.

Bile acids and the increased risk of colorectal tumours after truncal vagotomy

An association between colorectal cancer and previous peptic ulcer surgery is reported. In a prospective screening study, 100 asymptomatic patients (80 men and 20 women) who had undergone truncal vagotomy at least 10 years previously were investigated by barium enema, colonoscopy and gallbladder ultrasonography. Control data were obtained from forensic autopsy subjects. The incidence of neoplasms greater than or equal to 1.0 cm in the vagotomized group was 14 per cent (11 adenomas, 3 carcinomas) and 3 per cent in controls (P = 0.01). Duodenal bile obtained at endoscopy from 21 vagotomized patients with normal gallbladders and from 21 control patients undergoing endoscopy was analysed by high performance liquid chromatography. The mean percentage of cholic (CA), chenodeoxycholic (CDCA), deoxycholic (DCA) and lithocholic (LCA) acids in the bile of vagotomized patients was 32.3, 45.6, 20.7 and 1.4 per cent respectively compared with 45.3, 36.2, 17.9 and 0.7 per cent respectively in controls. The increased proportions of CDCA and LCA and decreased proportions of CA in the duodenal bile of vagotomized patients were significant (P less than 0.001; P = 0.02; P = 0.007). Abnormalities in bile acid metabolism may help to explain the increased risk of colorectal neoplasia 10 years after truncal vagotomy.