Can aspirin prevent gallstone recurrence after successful extracorporeal shockwave lithotripsy?

Extracorporeal shockwave lithotripsy (ESWL) is a feasible procedure for the treatment of gallbladder stones in humans. Well-selected patients can achieve stone-free rates in a high percentage. With the gallbladder in situ, these patients are at risk of stone recurrence. There is considerable evidence that aspirin prevents cholesterol gallstone formation in animal models and may prevent gallstone recurrence in man. We attempted to clarify the risk of gallstone recurrence after successful piezoelectric lithotripsy in patients taking either low-dose aspirin or no medication. The first 45 patients shown to be completely free from stones after ESWL were randomized into two groups. One group received 100 mg aspirin daily; the other group did not receive any further medical therapy. Patients were further examined on an average of 19.6 months and 21.9 months, respectively. In the aspirin group the recurrence rate was 18.2%, whereas 21.7% of the patients in the control group developed recurrent stones. Seventy-eight per cent of these patients also had a recurrence of biliary pain. By life-table analysis we had, after a follow-up period of 24 months, a stone recurrence rate of 25% (+/- 11) in the aspirin group and 34% (+/- 14) in the control group. Our results indicate that recurrence prophylaxis remains one of the central questions in ESWL. In this preliminary study, 100 mg of aspirin daily was not able to reduce the recurrence rate after successful ESWL. Further studies will have to show whether higher doses of aspirin or other ways of preventing gallstone after ESWL are possible.