GALLSTONE DISSOLUTION WITH ORAL BILE-ACID THERAPY - IMPORTANCE OF PRETREATMENT CT SCANNING AND REASONS FOR NONRESPONSE

In patients with cholesterol-rich gallbladder stones and a patent cyst ic duct, complete stone clearance rates of 65-90% have been reported w ith oral bile acids (OBAs) alone or with adjuvant lithotripsy (extraco rporeal shock-wave lithotripsy; ESWL). The aims of the present study w ere to analyze pretreatment gallstone characteristics that predict the speed and completeness of dissolution with OBAs +/- ESWL, and to asse ss, in patients with incomplete dissolution, the reasons for the poor response. We compared pretreatment gallstone characteristics in 43 pat ients who became stone-free after a median of 9 months OBAs +/- ESWL w ith those in 43 age-and sex-matched patients whose stones failed to di ssolve after two years of treatment. In those with incomplete gallston e dissolution, we repeated the oral cholecystogram and computed tomogr am (CT) and, in selected patients, obtained gallbladder bile by percut aneous fine-needle puncture. In patients who became stone-free, those with stones that were isodense with bile and/or had CT scores of <75 H ounsfield units had the fastest dissolution rates. In the 43 nonrespon ders, the main causes for treatment failure were impaired gallbladder contractility and acquired stone calcification. CT-lucent, noncholeste rol stones, or failure of desaturation of bile with the prescribed bil e acids, occurred in a minority. We conclude that the pretreatment CT attenuation score predicts both the speed and completeness of gallston e dissolution. In patients with incomplete stone dissolution, the comb ination of oral cholecystography, CT, and analysis of gallbladder bile will determine the underlying reasons for treatment failure in most, but not all, cases.