Low-dose chenodiol to prevent gallstone recurrence after dissolution therapy

Gallstone recurrence after successful lithotripsy

We report the recurrence rate of gallstone within 5 years after successful lithotripsy. One hundred and fifty consecutive patients (solitary stones, 102 patients; multiple stones, 48 patients) were followed up for a median of 42 months (range 6-72) after stone clearance and cessation of bile acid therapy. No patient received any therapy to prevent recurrence. Thirty-seven patients developed recurrent gallstones. Probabilities of recurrence were (mean +/- SD) 6.6% +/- 2%, 15.7% +/- 3%, 22.8% +/- 3.6%, 29.7% +/- 4.5%, 32.2% +/- 5% at 1, 2, 3, 4 and 5 years, respectively. The recurrence rate was lower in patients who had solitary stones than in patients with multiple stones (26.1% versus 47% at 5 years, respectively; p<0.009 - log rank test). Only five patients developed recurrent symptoms or stone complication (14%). We conclude that the recurrence rate after successful lithotripsy is lower than expected from dissolution studies, due to a low recurrence rate in patients who had solitary stones.

Gallstone recurrence after direct contact dissolution with methyl tert-butyl ether

To determine the rate and characteristics of gallstone recurrence after direct contact dissolution with methyl tert-butyl ether, 60 consecutive patients were followed for up to 4.5 years (median 2.2 years) after complete disappearance of all stone residues and debris and cessation of adjuvant bile acid therapy. Initial gallstones had been multiple in all but four patients. Twenty-eight of the 60 patients developed recurrent gallstones. The cumulative risk of gallstone recurrence (actuarial analysis) was 23 +/- 6%, 34 +/- 7%, 55 +/- 8%, and 70 +/- 9% at one, two, three, and four years, respectively. The recurrent stones were usually multiple and small (6 +/- 4 mm). Gallstone recurrence was associated with recurrent biliary pain in two patients, one of whom developed acute cholecystitis. Recurrent stones were cleared completely by bile acid medication with or without shock-wave lithotripsy in 61 +/- 15% of patients at one year (actuarial analysis). In conclusion, gallstone recurrence after successful contact dissolution of multiple stones with methyl tert-butyl ether has to be expected in a high percentage of patients. Most patients, however, remain free of biliary pain during long-term follow-up.

Effect of cisapride on gallbladder motility after extracorporeal shock-wave lithotripsy

BACKGROUND/AIMS

Altered gallbladder motility is regarded as one of the important factors involved in the formation and recurrence of gallstones. Previous studies have suggested that cisapride increases postprandial gallbladder contraction and may therefore be theoretically useful in preventing stone recurrence. The aim of our study was therefore to investigate the effect of cisapride on gallbladder motility in stone-free patients after extracorporeal shock-wave lithotripsy, as compared to healthy volunteers pair-matched for age and sex.

METHODS

Each subject received cisapride or placebo in a double-blind, cross-over, random order. Gallbladder volumes were measured by ultrasonography in the fasting state and after intake of a standard liquid meal. Plasma cholecystokinin levels were determined by radioimmunoassay.

RESULTS

Fasting gallbladder volumes were smaller in patients as compared to volunteers (20.7 +/- 1.3 ml vs. 46.0 +/- 9.2 ml; p < 0.05) but were not modified by cisapride (21.1 +/- 1.7 ml vs. 58.6 +/- 11.3 ml). The maximal postprandial decrease in gallbladder volume was similar in patients and volunteers (64.5 +/- 12% vs. 62 +/- 10%; NS) and was not significantly altered by cisapride (59 +/- 9.4% vs. 54 +/- 9%; NS). In patients, cisapride increased integrated postprandial gallbladder volume by accelerating gallbladder refilling as compared to placebo by 37 +/- 15% (p < 0.05). Integrated cholecystokinin plasma levels were similar in patients and volunteers and were 13.4 +/- 4.7% higher after cisapride as compared to placebo (p < 0.05).

CONCLUSIONS

The results of this study suggest that cisapride does not alter postprandial gallbladder contraction but accelerates gallbladder refilling in patients free from gallstones after extracorporeal shock-wave lithotripsy. This effect of cisapride is probably due to an acceleration of gastric emptying also causing a secondary enhanced cholecystokinin release.

Pathogenic factors in early recurrence of cholesterol gallstones

BACKGROUND/AIMS

Supersaturation of bile with cholesterol, rapid nucleation of cholesterol crystals, and/or incomplete emptying of the gallbladder are believed to be required for gallstone formation. The importance of these factors for the recurrence of gallbladder stones was studied.

METHODS

Twenty patients, untreated after successful shock wave therapy, were studied in a matched case-control design for bile acid turnover, composition of duodenal bile, and gallbladder emptying. In 10 of them, gallstones had recurred within 12 +/- 2 months (X +/- SEM); the other 10 had been free of stones since 22 +/- 3 months.

RESULTS

In each group, duodenal bile was supersaturated with cholesterol in 8 of 10 patients and showed abnormal nucleation time of cholesterol crystals in half of the patients. Patients with recurrent stones had smaller pool sizes of cholic acid (-43%) and enhanced conversion of cholic acid to deoxycholic acid. The odds for stone recurrence were ninefold increased in the presence of excessive deoxycholic acid (exceeding cholic acid) in the bile acid pool or incomplete emptying of the gallbladder (residual volume > 5 mL) in response to cholecystokinin. The odds ratio was over 20-fold increased when incomplete emptying of the gallbladder coincided with supersaturated bile or with excessive deoxycholic acid.

CONCLUSIONS

Enhanced conversion of cholic acid to deoxycholic acid and incomplete emptying of the gallbladder could be important cofactors for the recurrence of gallstones.

Gallstone recurrence after shock-wave therapy

BACKGROUND/AIMS

The long-term outcome of nonoperative gallstone therapy depends on both absence of stones and absence of biliary pain. The aim of the present study was to determine the rate of stone recurrence and the rate of symptoms within 5 years after successful shock wave lithotripsy combined with bile acid therapy.

METHODS

One hundred consecutive patients (single stones, n = 89; 2 or 3 stones, n = 11) were followed up for a median of 4.3 years after stone disappearance and discontinuation of bile acids.

RESULTS

Twenty-three of the 100 patients developed recurrent stones. Calculated by actuarial analysis, the recurrence rate was 7% +/- 3%, 11% +/- 3%, 13% +/- 4%, 20% +/- 5%, and 31% +/- 7% (mean +/- SD) at 1, 2, 3, 4, and 5 years, respectively. The recurrent stones were small (6 +/- 5 mm) and were associated with recurrent biliary pain in 14 (61%) of the 23 patients. Repeated shock wave lithotripsy and/or bile acid medication resulted in stone disappearance in only 10 of 20 patients with recurrence.

CONCLUSIONS

The long-term rate of stone recurrence after lithotripsy of primarily solitary gallbladder calculi is lower than expected from post-bile acid dissolution trials. Recurrence of stones frequently is associated with recurrence of biliary pain.

Gallstone disease: current therapy

After a decade of effort to develop a minimalist alternative to standard cholecystectomy as the treatment for gallstone disease, laparoscopic cholecystectomy (LC) has emerged as the treatment of choice. Gallstone dissolution and lithotripsy failed to meet the tests of applicability and reliability. In fact, lithotripsy was denied approval by the US Food and Drug Administration in 1989. LC achieves the benchmark of treatment--removal of the diseased gallbladder and its stones--with less pain, disability, and disfigurement than standard surgery. The procedure is applicable in more than 90% of cases, being limited primarily by the severity of inflammation and the surgeon's experience. During the past 3 years, the special instrumentation has improved and operative techniques have been standardized resulting in fewer complications. For these reasons, laparoscopic surgical techniques are now being applied to a widening array of procedures including hernia repairs, bowel resections, antireflux procedures, common bile duct stone removal, lymph node dissections, and peptide ulcer disease treatment.

Gall stone recurrence and its prevention: the British/Belgian Gall Stone Study Group's post-dissolution trial

The British/Belgian Gall Stone Study Group (BBGSG) post-dissolution trial was a prospective, multicentre, randomised, double blind trial of: (i) low dose ursodeoxycholic acid, (ii) placebo, and (iii) a high fibre, low refined carbohydrate diet in the prevention of gall stone recurrence in patients with complete gall stone dissolution. Further aims included establishing the timing and frequency of recurrence and its association with biliary symptoms, a comparison of the sensitivity of ultrasonography v oral cholecystectography in detecting recurrent stones, and a search for risk factors predicting recurrence. Ninety three patients entered the study, and 82 were followed up for up to five years (mean (SEM) 28 (1.5) months) with six monthly ultrasonography and yearly oral cholecystectography. There were 21 recurrences (26 by oral cholecystectography or ultrasonography, or both), only two of which were symptomatic, which were detected between 12 and 42 months after trial entry. This corresponded to an actuarial recurrence rate of 33.9 (7.0%) by lifetable analysis at 42 months and subsequently. There were four recurrences in the ursodeoxycholic acid, six in the placebo, and 11 in the diet groups, corresponding to 21.9 (9.9)%, 27.4 (10.1)%, and 45.8 (12.4)% respectively at 42 months by lifetable analysis (NS). Variables including age, obesity, menopausal state, pregnancy, and oestrogen containing drugs were not shown to affect recurrence rate. Men had more frequent recurrence than women (NS). Patients who had had multiple stones experienced more recurrences than did those with single stones (NS). Recurrence did not occur in patients who took non-steroidal anti-inflammatory drugs (NSAIDs) (p < 0.02). The stone free interval between stone dissolution and trial entry proved to be important--those stone free > nine months had a recurrence rate of only 12.7 (6.0)% at 42 months compared with 55.4 (12.5)% in those stone free < nine months (p < 0.01). There was imbalance between the ursodeoxycholic acid and placebo groups for this factor, and after applying a statistical correction, the adjusted recurrence rate in the ursodeoxycholic acid group was 15% compared with 30% in both placebo and diet groups (NS). These data suggest that after medical dissolution, the risk of gall stone recurrence is not reduced by a high fibre, low refined carbohydrate diet: it may be lowered, but not abolished, by low dose ursodeoxycholic acid.

Future directions for conservative treatment of gallbladder calculi

Recent conservative gallstone treatments provide rapid relief from symptoms, but all have a potential for stone recurrence. They are indicated in patients who are unfit or unwilling to undergo cholecystectomy. Wider application will depend on selection of patients who are at least risk of recurrence, or on development of effective prophylactic strategies.

Management of recurrent gallstones

The risk of gallstone recurrence following non-surgical treatment has been overestimated in the past for two reasons: (1) diagnosis of primary gallstone dissolution was based on oral cholecystography; and (2) gallstone recurrence was expressed as a cumulative recurrence rate. Results based on better methodologies for diagnosis of gallstones (ultrasonography) and for calculation of results (life-table analysis) have indicated that gallstones recur in about 50% of patients, and that the risk of recurrence is confined mainly to the first 5 years after dissolution. Pretreatment gallstone characteristics, but not patient characteristics, are important risk factors for gallstone recurrence. Multiple stones are more likely to recur than solitary stones, a phenomenon attributable to the presence of a potent pronucleating factor in the bile of patients with multiple stones. This observation, and the finding that NSAID administration may reduce gallstone recurrence via inhibition of mucin secretion, suggests that the nucleation defect might be a key factor in the pathogenesis of recurrent gallstones. Prophylaxis with low-dose CDCA or UDCA has proven ineffective for preventing gallstone recurrence, although it may reduce it. Since the majority of recurrent gallstones are small when first seen because of regular ultrasonographic follow-up, multiple, radiolucent and in functioning gallbladders, they are amenable to bile acid retreatment, and intermittent bile acid therapy is probably a viable strategy for long-term management of cholesterol cholelithiasis.

Gallstone disease. Pathophysiology, epidemiology, natural history, and treatment options

In 1991, only symptomatic gallstones should be treated. The treatment of choice for all gallstones continues to be surgical removal. Except for stones in the common bile duct, which are amenable to removal by endoscopic papillotomy, nonsurgical treatment of gallstones should be investigated further before it can have widespread applicability. The major challenge in the future may be medical prevention of gallstone formation in susceptible individuals. Laparoscopic cholecystectomy seems to have moved to the forefront of surgical therapy in patients who are candidates for the procedure.

Treatment of symptomatic cholelithiasis in France. A decision analysis comparing cholecystectomy and biliary lithotripsy

To determine the potential role of extracorporeal shock wave lithotripsy (ESWL) in the treatment of symptomatic gallstone patients in France, a simulation model evaluated the health and economic effects of three different treatment strategies. Decision analysis of conventional cholecystectomy alone and either of two strategies using a combination of biliary lithotripsy and conventional cholecystectomy reveals that a strategy employing biliary ESWL results in a significant number of successfully treated patients, thus avoiding the risks and costs of abdominal surgery. Moreover, cost analysis shows that expanding the use of lithotripsy to all patients for whom the procedure is indicated increases the average cost per successfully treated patient, but, more importantly, decreases the overall costs incurred by the cohort. From a societal viewpoint, a policy using biliary ESWL in appropriate patients is superior to one of cholecystectomy alone, from both clinical and economic perspectives.

Pathophysiology and pharmacotherapy of cholelithiasis

Several factors are involved in the development of gallstone formation: formation of supersaturated bile; nucleation; formation, retention and adhesion of cholesterol crystals and eventually stone growth. The dynamics of the gallbladder may play a key role in the overall process. The pathophysiologic theory of cholesterol gallstone formation and the knowledge of their physico-chemical properties support the modern concept of gallstone therapy. Chenodeoxycholic and ursodeoxycholic have been widely used as cholesterol gallstone dissolving agents and evaluated in terms of efficacy and safety.

Lithotripsy versus cholecystectomy for management of gallstones. A decision analysis by Markov process

Extracorporeal shock-wave lithotripsy is a new treatment method that effectively distintegrates radiolucent gallstones and is associated with a low complication rate. Using the model of a Markov process for decision analysis, survival and costs under four possible strategies to treat gallstones were compared: expectant management with cholecystectomy (EC) or lithotripsy (EL) reserved for symptomatic gallstones; prophylactic cholecystectomy (PC) or lithotripsy (PL) for all gallstones. Life expectancy for the different strategies varies by few days. Only if high annual rates of pain and complication occurred in subjects with silent gallstones would both prophylactic procedures marginally increase life expectancy. Prophylactic cholecystectomy then would be more cost-effective than prophylactic lithotripsy. Expectant strategies remain much cheaper than prophylactic management over a broad range of probability values and procedural costs. Expectant use of lithotripsy costs less than cholecystectomy. A low success rate of lithotripsy would raise the direct costs of lithotripsy above those of cholecystectomy but leave total costs of both strategies in the same order of magnitude. Lithotripsy appears to be a feasible alternative to treat symptomatic but not asymptomatic gallstones.

Non-surgical options for the management of gallstone disease: an overview

The modalities for the non-surgical treatment of gallstones include oral dissolution by bile salts, local dissolution by methyl-tert-butyl-ether (MTBE), extracorporeal shockwave lithotripsy (ESWL) and percutaneous gallstone clearance. The results of oral bile salt therapy for cholesterol stones have been disappointing, and the only indication for this treatment is after ESWL. The high efficacy initially reported for MTBE has not been confirmed by subsequent experience in other centres: this therapy is toxic and best confined to specialized centres. ESWL, though effective in noncalcified stones, has limited overall applicability (approx. 15%) and is frequently followed by recurrence despite maintenance therapy with oral bile salts. Percutaneous gallstone clearance (radiologic or laparoscopic) has been superseded by laparoscopic cholecystectomy. This offers definitive treatment in a single session and has significant advantages over open cholecystectomy in terms of short hospital stay and accelerated recovery with early return to work or full activity. Destruction of the gallbladder by sclerosant agents (chemical cholecystectomy) requires further experimental evaluation before its introduction to clinical practice.

Nonsurgical treatment of cholelithiasis. An analysis of clinical opportunity

This article examines the potential impact of recently developed nonsurgical treatments for gallstones on patient care and resource utilization. Using epidemiological and efficacy data from the literature and current patient selection criteria, the authors evaluate UDCA, extracorporeal shock-wave lithotripsy, and direct instillation of methyltertbutyl ether in terms of short-term clinical results, health policy, and economic implications.

Medical management of gallstones: a cost-effectiveness analysis

OBJECTIVE

Ursodeoxycholic acid (ursodiol) is an oral dissolution agent recently approved by the Food and Drug Administration for treatment of cholelithiasis. The authors conducted a cost-effectiveness analysis comparing ursodiol with elective cholecystectomy and expectant management for men and women of ages 50 and 70 with typical chronic biliary symptoms.

DESIGN

Using published literature and national cost data, the authors performed a decision analysis in which the outcome measures were life expectancy, quality-adjusted life expectancy, and expected lifetime treatment cost.

PATIENTS

The analysis applies to patients with symptoms of biliary colic, noncalcified gallstones less than 20 mm in diameter, and functioning oral cholecystograms, who are candidates for elective cholecystectomy. Excluded were patients with acute cholecystitis or known or suspected common bile duct stones.

RESULTS

Ursodiol is both clinically advantageous and less expensive than surgery for symptomatic men aged 64 or more, and for symptomatic women aged 69 or more. At ages younger than these, the clinical advantage of surgery is small and could be nullified if ursodiol were targeted at patients for whom dissolution is most likely to be effective, based on evidence of stone size and composition. Expected lifetime costs of ursodiol range from $300-400 more than surgery for 50-year-olds to $700-1,000 less than surgery for 70-year-olds. Ursodiol is the preferred choice for patients throughout this age range who are at significantly elevated risk of operative mortality.

CONCLUSION

Ursodiol is a clinically advantageous and cost-effective alternative to elective cholecystectomy, especially for older and high-risk patients.

Early gallstone recurrence rate after successful shock-wave therapy

Extracorporeal shock-wave lithotripsy combined with adjuvant bile-acid dissolution therapy results in complete clearance of stone fragments in a high percentage of selected patients with radiolucent gallbladder calculi. With the gallbladder in situ, these patients are at risk of stone recurrence. Therefore, the early rate of stone recurrence after successful lithotripsy was evaluated. Fifty-eight of the first 60 consecutive patients who became stone free underwent follow-up examinations at least 1 yr (range, 12-37 mo; mean +/- SD, 18 +/- 6) after discontinuation of adjuvant bile-acid therapy. Five patients reported recurrent biliary pain within 1 yr after lithotripsy, and recurrent gallstones were detected. Fifty-three patients were asymptomatic during the first yr, and no recurrence was detected. Thus, the rate of gallstone recurrence was 9% within 1 yr. The rate of gallstone recurrence up to 3 yr was estimated by actuarial analysis. The probability of stone recurrence was 11% (+/- 4%) at 1.5 yr, and no further increase was observed up to 3 yr. Gallstone recurrence within 1 yr after successful shock-wave therapy has to be expected in approximately the same percentage of patients as has been reported in earlier postdissolution trials. It causes recurrent biliary pain in most cases.

Gallstone recurrence after successful oral bile acid treatment. A 12-year follow-up study and evaluation of long-term postdissolution treatment

Recurrence is a major problem in the medical treatment of gallstones but its extent is still uncertain. The aim of this study was to determine the magnitude of this event and to assess the effectiveness of a postdissolution treatment in preventing it. We evaluated the long-term recurrence rate after 96 confirmed dissolutions observed in 86 subjects (71 women, 15 men) over a 12-yr follow-up period. A low-dose postdissolution treatment (ursodeoxycholic acid, 300 mg/day) was administered to 36 subjects, whereas in the remaining 60 cases no postdissolution treatment was given. By actuarial life-table analysis, the cumulative proportion of gallstone recurrence was 12.5% at the first year, rising to 61% at the 11th year. Postdissolution treatment was effective in reducing the frequency of gallstone recurrence (p = 0.0067), but this was mainly related to its effect on younger subjects (less than or equal to 50 yr old). In older subjects the recurrence rate was unaffected by treatment. The probability of gallstone recurrence was significantly higher in subjects with multiple stones before dissolution treatment than in those who had had solitary stones (p = 0.0091). No other factor predictive of gallstone recurrence could be identified.

Pathophysiology and treatment of gallstones

Spurred on by the discovery of "lithogenic bile" as a precursor, there has been much attention focused on the pathophysiology and treatment of gallstones. The article reviews the progress to date regarding the epidemiology, pathophysiology, diagnosis, therapy, and recurrence/prevention of gallstones.

Review article: dissolution of gallstones in the biliary tree

There are a variety of methods for dissolving gallstones in the biliary tree, which include oral therapy and direct contact dissolution. Cholesterol gallstones are most amenable to dissolution. Developments in non-operative physical methods to remove gallstones (particularly endoscopic papillotomy and extracorporeal shock-wave lithotripsy have diminished the use of chemical dissolution. However, in selected patients, there remains a place for chemical dissolution, but often in conjunction with the physical techniques.

Low-dose ursodeoxycholic acid prolongs cholesterol nucleation time in gallbladder bile of patients with cholesterol gallstones

The high rate of stone recurrence represents a drawback of non-surgical therapy of cholesterol gallstone disease. Although most studies report that long-term bile acid treatment does not have protective effects, preliminary results suggest that low-dose ursodeoxycholic acid decreases the rate of gallstone recurrence in a subgroup of younger patients. To clarify the underlying mechanism we investigated whether low-dose ursodeoxycholic acid treatment influences biliary cholesterol saturation and/or nucleation time of cholesterol. Ten patients with cholesterol gallstones and functioning gallbladder received 250 mg ursodeoxycholic acid/day at bedtime 6-10 days prior to cholecystectomy. Eleven patients with cholesterol gallstones without treatment served as controls. Cholesterol crystals were present in the gallbladder bile of 7 out of the 10 patients receiving ursodeoxycholic acid and in all control biles. Ursodeoxycholic acid treatment significantly (P less than 0.02) decreased the cholesterol saturation index (mean +/- S.E.: 0.94 +/- 0.05 vs. 1.43 +/- 0.18) and led to an approximately 5-fold prolongation (P less than 0.005) of the cholesterol nucleation time (mean +/- S.E.: 12.0 +/- 2.4 vs. 2.3 +/- 0.7 days). We conclude that low-dose ursodeoxycholic acid might be effective in the prevention of post-dissolution gallstone recurrence by both decreasing cholesterol saturation and prolonging cholesterol nucleation time.

Efficacy of chenodeoxycholic acid and ursodeoxycholic acid for lowering cholesterol saturation index of gallbladder in patients with a sphincterotomy

After endoscopic retrograde sphincterotomy, patients with an intact gallbladder are at risk for developing symptoms or complications of gallbladder stones. Medical dissolution of such stones would be desirable, especially in elderly patients with an increased surgical risk. However, sphincterotomy alters emptying dynamics of the gallbladder and markedly reduces bile salt pool size, effects that may alter response to chenodeoxycholic acid or ursodeoxycholic acid treatment. Studying two groups of 5 patients with an intact gallbladder after endoscopic retrograde sphincterotomy, we found that 15 mg/kg.day of chenodeoxycholic acid increased the mean (+/- SEM) biliary percentage of chenodeoxycholic acid from 35.5% +/- 4.0% to 88.8% +/- 1.9% (p less than 0.01) and decreased the mean saturation index of gallbladder bile from 1.02 +/- 0.22 to 0.55 +/- 0.08 (p less than 0.05). Ursodeoxycholic acid (10 mg/kg.day) increased the mean biliary percentage of ursodeoxycholic acid from 5.6% +/- 1.5% to 44.7% +/- 5.8% (p less than 0.01) and decreased the mean saturation index of gallbladder bile from 1.04 +/- 0.25 to 0.57 +/- 0.03 (p less than 0.05). A long-term trial of bile acid treatment in sphincterotomy patients with stones in an intact gallbladder is needed.

Cholesterol gallstone disease: the current status of nonsurgical therapy

Gallstone disease is a common disease that appears to be related to a Western diet. The underlying pathogenesis is a subtle alteration in the liver such that excessive cholesterol is extracted from the liver cell by bile acids undergoing an enterohepatic recirculation. Gallstone disease progresses through well-defined stages, beginning with a bile supersaturated with cholesterol and proceeding to crystal formation, stone growth, and finally symptoms caused by impaction of a stone in either the cystic duct or the common bile duct. The natural history is that most stones never cause symptoms. Stones that cause symptoms have been present for an average of 12 years. The treatment of truly asymptomatic stones should be observation. Ultrasonography of the right upper quadrant is the gold standard for the diagnosis of stones in the gallbladder. Endoscopic retrograde cholangiopancreatography (ERCP) is the gold standard for the diagnosis of stones in the common bile duct. Oral cholecystogram (OCG) helps select patients who have noncalcified, floating stones that may be dissolved with bile acids or methyl tertiary butyl ether (MTBE). Therapy with chenodiol has been a disappointment because of a low complete response rate. The ideal candidate for attempted dissolution with chenodiol would be a thin woman with hypercholesterolemia and a small number of symptomatic, small, floating, radiolucent gallstones. Ursodeoxycholic acid (Urso), when it is available, will have all of the attributes of chenodiol and virtually none of the side effects. Rapid dissolution of gallstones with MTBE shows great promise of being a generally available means of dissolving gallstones. Extracorporeal shock wave lithotripsy also shows promise, but its general availability may be limited by the cost of the equipment needed. As of now, the treatment of choice for symptomatic gallstones remains cholecystectomy, unless there is a compelling reason not to operate.

Administration of a terpene mixture inhibits cholesterol nucleation in bile from patients with cholesterol gallstones

Patients with cholesterol gallstones referred to elective cholecystectomy were randomly assigned prior to operation to no treatment (n = 14), treatment with one capsule t.d.s. (n = 12) or two capsules t.d.s. (n = 11) of a terpene mixture (Rowachol). Patients with pigment stones (n = 7) or no biliary tract disease (n = 5) were also studied. Lipid composition, presence of cholesterol monohydrate crystals, and nucleation time were determined in gallbladder bile aspirated during surgery. Cholesterol saturation was similar in the different groups. Crystals were present in all cholesterol gallstone patients without treatment and in none of the controls. In one of the patients treated with one capsule and four of the patients treated with two capsules crystals could not be detected. The terpenes prolonged nucleation time from 2.8 to 5.8 days (one capsule; P less than 0.05) and to 9.5 days (two capsules; P less than 0.001), respectively; but nucleation did not occur in seven controls. Although the mechanism by which the terpene mixture inhibits the formation of cholesterol crystals in bile was not determined, the findings suggest that the terpene mixture might be a useful agent for a clinical trial to test whether they will prevent recurrence of gallstones after medical dissolution.

Agents for gallstone dissolution

Numerous methods are presently available for gallstone dissolution, including oral bile salts; cholesterol solvents such as mono-octanoin and methyl tert-butyl ether; calcium or pigment solvents such as EDTA and polysorbate; mechanical extraction techniques through a T-tube tract or after endoscopic sphincterotomy; or fragmentation methods such as ultrasonography or electrohydraulic lithotripsy, lasers, and extracorporeal shock waves. Which, if any, of these methods will be appropriate for an individual patient depends on the type of stones, whether they are in the gallbladder or bile ducts, whether access to the biliary tree is available, the patient's age and general medical condition, and the availability of expert radiologists, endoscopists, and newer equipment. In the United States, the only available oral bile salt for cholesterol gallstone dissolution is chenodeoxycholate. Ursodeoxycholate, which is more rapid and less toxic, has not been approved by the Federal Drug Administration. These agents are most effective in thin women with small, floating, radiolucent cholesterol gallstones in a functioning gallbladder. Only about half of this small subset of patients, however, will experience partial or complete dissolution of stones in 6 to 12 months. Moreover, recurrence is very likely, and the potential toxicity of long-term therapy is unknown. Thus, for most patients, cholecystectomy remains the most cost-effective and, perhaps, safest option. Intragallbladder instillation of methyl tert-butyl ether and extracorporeal shock wave therapy are also likely to be applicable to only small subsets of patients and to be associated with high recurrence rates. In patients with retained ductal cholesterol stones and access to the biliary tree, mono-octanoin therapy is advantageous in that it can be begun as soon as cholangiography demonstrates no extravasation. In properly selected patients, a 90 percent success rate with mono-octanoin infusion can be expected within a week. Radiologic or endoscopic extraction techniques require maturation of a relatively straight T-tube tract but are not dependent on the type of stone. In the hands of experts, these techniques are highly successful. In postcholecystectomy patients without access to the biliary tree, endoscopic sphincterotomy has become the preferred method of management and can be expected to succeed in more than 90 percent of patients. At this point, the exact role for ultrasonic or electrohydraulic lithotripsy and lasers is unknown. However, these techniques may be applicable in the future in patients with retained bile duct stones in whom extraction and infusion techniques have failed.

Medical management of cholesterol gallstones

Cholesterol gallstones are a significant cause of morbidity in the U.S. Methods used to treat gallstones include cholecystectomy or medical dissolution. The primary drugs used for the dissolution of cholesterol gallstones are two bile acids, chenodeoxycholic acid and ursodeoxycholic acid. Complete or partial gallstone dissolution rates using chenodeoxycholic acid have ranged from 30 to 80 percent. Factors affecting gallstone dissolution using the bile acids include the dosage and administration schedule, obesity, the stone characteristics, diet, and the duration of therapy. The adverse effects of chenodeoxycholic acid include gastrointestinal complaints, hepatotoxicity, and increased serum cholesterol. Ursodeoxycholic acid, which is investigational, differs from chenodeoxycholic acid in its mechanism of action. Ursodeoxycholic acid has similar efficacy with chenodeoxycholic acid, at a lower daily dosage, with less gastrointestinal and hepatic adverse effects. If appropriate patient selection is used, the response rate to medical therapy can range from 50 to 80 percent.