Anastomotic configuration and mucosal 5-aminosalicylic acid (5-ASA) concentrations in patients with Crohn's disease: A GISC study

OBJECTIVE: Recurrence of Crohn's disease quite inevitably occurs after rese ction of distal small bowel and proximal colon, involving the neoterminal i leum close to the anastomosis. Oral 5-aminosalicylic acid (5-ASA) administe red soon after surgery delays recurrence and reduces its severity. We recen tly observed that in operated patients submitted to prophylactic treatment with oral 5-ASA the rate of recurrence was significantly higher in those wi th end-to-end anastomosis than in those with other types of anastomosis (en d-to-side, side-to-side). The hypothesis investigated in the present study was that patients with end-to-side or side-to-side anastomosis would benefi t from a higher mucosal concentration of 5-ASA with respect to patients wit h end-to-end anastomosis. Therefore, the mucosal 5-ASA concentration was me asured in the perianastomotic area of both groups. METHODS: The study was carried out in 19 patients submitted to radical surg ery for Crohn's ileitis or ileocolitis, under oral prophylactic treatment w ith 5-ASA (Asacol). All patients were on regular endoscopic follow-up and w ere free of recurrence. Two biopsies were collected 3 cm from the anastomos is, in the neoterminal ileum, and two biopsies were collected at the coloni c site 3 cm below the anastomosis. 5-ASA concentrations (ng/mg) were measur ed in tissue homogenates by high-performance liquid chromatography (HPLC) w ith electrochemical detection. RESULTS: The mucosal concentration of 5-ASA in the neoterminal ileum was si gnificantly lower in patients with end-to-end anastomosis than in those wit h other types of anastomosis (median values: 29.4 ng/mg vs 92.9 ng/mg respe ctively; p < 0.001). Six of 10 patients (60%) with end-to-end anastomosis, but none of the nine patients with other types of anastomosis, showed 5-ASA mucosal concentrations <40 ng/mg at the neoterminal ileum. On the contrary , no patients with end-to-end anastomosis showed mucosal concentrations of 5-ASA >90 ng/mg, compared with the 57% of patients in the group with other types of anastomosis. No differences were observed for colonic biopsies. CONCLUSIONS: The different mucosal concentrations in these two groups may b e explained by the difference in segmental transit time induced by the diff erent anastomotic configurations. A slower preanastomotic transit time, dem onstrated in patients with end-to-side or side-to-side anastomosis, could o ffer a prolonged contact time between the intestinal content and the mucosa , resulting in an increase in drug absorption. (Am J Gastroenterol 2000:95: 1486-1490. (C) 2000 by Am. Coll. of Gastroenterology).