Apolipoprotein E4 genotype and gallbladder motility influence speed of gallstone clearance and risk of recurrence after extracorporeal shock‐wave lithotripsy

Abstract Extracorporeal shock-wave lithotripsy (ESWL) is an effective treatment in selected gallstone patients, but stone recurrence is a major drawback. Factors potentially influencing gallstone clearance and recurrence were studied in 84 patients in whom stone dissolution was diagnosed after ESWL plus bile salt therapy for initial solitary (n = 55) or multiple (n = 29) radiolucent stones. Apolipoprotein E (apoE) genotyping and gallbladder motility (sonography) were studied in a representative subgroup of patients (n = 50). The median follow-up after ESWL was 36 months (range, 4.5-67 months). Gallstone clearance was achieved after 8.7 months (range, 0.2-30 months). Independent factors significantly enhancing gallstone clearance were the presence of E4 allele; small initial gallstone size and number; effectiveness of fragmentation; and good gallbladder emptying (P = .002). Gallstone recurrence was seen in 30 patients after 18.6 months (range, 1.0-50 months). Cumulative gallstone recurrence rate (life-table analysis) was 15% within 1 year, increasing to 60% within 5.5 years. Although the probability of gallstone recurrence tended to be smaller in patients with initial solitary stones than in those with multiple stones during early follow-up, differences disappeared after long-term follow-up. Effective gallbladder emptying (residual volume