Cross-sectional evaluation of transmural healing in patients with Crohn's disease on maintenance treatment with anti-TNF alpha agents

Background: Transmural healing (TH) of Crohn’s disease (CD) is a still unexplored and interesting outcome correlated to concept of deep remission. Aim: To assess the rate of TH in CD patients treated with anti-TNF alpha agents using two cross-sectional procedures: bowel sonography (BS) and magnetic resonance enterography (MRE). Methods: We performed a 2-year observational longitudinal study, evaluating steroid-free clinical remis- sion (CR), mucosal healing (MH), and TH in CD patients who would complete a 2-year treatment period with anti-TNFs. All patients underwent endoscopy, BS, and MRE before and after 2 years of treatment. Results: Forty out of 80 CD patients were treated with anti-TNFs for 2 years. CR was achieved in 24 patients (60%) while MH in 14 (35%). Using BS, TH was observed in 10 patients (25%), while using MRE, TH was observed in 9 patients (23%) (k = 0.90; P < 0.01). A good agreement was observed between MH and TH, both using BS (k = 0.63; P < 0.01) and MRE (k = 0.64; P < 0.01). A poor agreement was found between CR and TH, with both BS and MRE (k = 0.27 and 0.29, respectively; P < 0.01); even though all patients with TH had achieved CR. Conclusions: TH can be achieved in about 25% of CD patients treated with anti-TNFs, as shown by BS and MRE. BS could be used as the first cross-sectional procedure to detect TH.