Perianal fistulae following infliximab treatment: clinical and endosonographic outcome

BACKGROUND: Management of perianal and rectovaginal fistulae complicating Crohn's disease (CD) is unsatisfactory. Infliximab is effective in the treatment of fistulating CD. However, reopening of fistulae is frequent, suggesting the persistence of deep fistula tracts despite superficial healing. In this study, the clinical and endosonographic behavior of perianal fistulae were evaluated following infliximab infusions, as well as the role of anal endosonography (AE) in predicting their outcome. METHODS: Thirty CD patients presenting with perianal and/or rectovaginal fistulae received an infusion of infliximab at a dose of 5 mg/kg at weeks 0 (entry into the study), 2, and 6. Laboratory and clinical assessments were repeated at same intervals and at week 10. AE was performed at entry and at week 10. Thereafter, the perianal region was re-examined every 6 months, and patients were investigated regarding draining of the fistula in the previous months. RESULTS: Fifteen patients (53.6%) showed closure of the fistulae at week 10, but only 5 patients had the fistula tracts disappeared at AE. Clinical and AE closure of rectovaginal fistulae was less prevalent than that of perianal fistulae [14.3% versus 63.6% at week 6 (p = 0.035); 28.6% versus 59.1% at week 10 (p = 0.21); 14.3% versus 22.7% at AE (p = 1.00)]. The behavior of fistulae was not affected by their number and AE classification, presence of rectal disease, or setons. Twenty patients with perianal fistulae were followed for a median of 15.5 months. Patients with closed perianal fistulae at week 10 and disappearance of fistulae tract at AE showed a lower relapse rate than those with endosonographic persistence of fistula tract. CONCLUSIONS: Infliximab can heal perianal and rectovaginal fistulae in approximately 60% and 30% of patients, respectively. Despite closure, most fistula tracts are still detectable at AE. Persistence of the internal tract is a condition at higher risk of fistula recurrence.