Topical dissolution of
cholesterol gallbladder stones using
methyl tert-butyl ether (
MTBE) is useful in symptomatic patients judged too ill for surgery. Previous studies showed that
ethyl propionate (EP), a C5
ester, dissolves
cholesterol gallstones rapidly in vitro, but differs from
MTBE in being eliminated so rapidly by the liver that blood levels remain undetectable. Our aim was to test EP as a topical dissolution agent for
cholesterol gallbladder stones. Five high-risk patients underwent topical dissolution of gallbladder stones by EP. In three patients, the
solvent was instilled via a
cholecystostomy tube placed previously to treat
acute cholecystitis; in two patients, a percutaneous transhepatic
catheter was placed in the gallbladder electively.
Gallstone dissolution was assessed by chromatography, by gravimetry, and by
catheter cholecystography. Total dissolution of
gallstones was obtained in four patients after 6-10 hr of lavage; in the fifth patient, partial
gallstone dissolution facilitated basketing of the stones. In two patients,
cholesterol dissolution was measured and averaged 30 mg/min. Side effects were limited to one episode of transient
hypotension and
pain at the infusion site; no patient developed
somnolence or
nausea.
Gallstone elimination was associated with relief of symptoms. EP is an acceptable alternative to
MTBE for topical dissolution of
cholesterol gallbladder stones in high-risk patients. The lower volatility and rapid hepatic extraction of EP suggest that it may be preferable to
MTBE in this investigational procedure.