Significance of endoscopic deep small bowel evaluation using balloon-assisted enteroscopy for Crohn’s disease in clinical remission

Background: Small bowel lesions of Crohn’s disease (CD) are known to be associated with a poor prognosis; however, endoscopic healing leads to favorable patients’ outcome. The aim of this study was to clarify the clinical impact of assessing deep small bowel lesions (DSB) using balloon-assisted enteroscopy (BAE) on CD patients in clinical remission. Methods: From January 2012 to July 2018, a total of 100 CD patients in clinical remission were enrolled to undergo trans-anal enteroscopy using single-balloon enteroscope. Endoscopic evaluations at the terminal ileum (TI) were performed using a partial Simple Endoscopic Score for CD (pSES-CD). Endoscopic evaluations at the DSB used a modified partial SES-CD (mpSES-CD). We evaluated the factors associated with relapse, and the correlation of endoscopic score between the TI and DSB. For this study, relapse was defined as hospitalization within a year from enteroscopy. Results: 30 patients (30.0%) relapsed within a year from enteroscopy. Multivariate logistic regression analysis revealed that the Harvey–Bradshaw Index (OR 1.77, 95% CI 1.18–2.65; p = 0.003) and an mpSES-CD at DSB (OR 3.10, 95% CI 1.86–5.15; p = 0.001) were independent predictors for relapse, whereas a SES-CD at the TI did not exhibit independence. There was a significant correlation trend between the relapse rate and greater than 5 points of an mpSES-CD at DSB; however, there was no correlation between the relapse rate and pSES-CD at the TI. Conclusion: Even when Crohn's disease is in remission, it is important to evaluate DSB using BAE to assess endoscopic mucosal healing.