Transmural Response and Transmural Healing Defined by Intestinal Ultrasound: New Potential Therapeutic Targets?

Intestinal ultrasound [IUS] is a useful modality to monitor patients with inflammatory bowel disease [IBD]. Little is known about the use of IUS and appropriate definitions for transmural response [TR] and healing [TH]. We aimed to establish the use of IUS in monitoring TH as a potential target in routine medical practice.Based on the prospective, non-interventional, multicentre studies TRUST and TRUST&UC, we conducted a post-hoc analysis of 351 IBD patients with increased bowel wall thickness [BWT]. We analysed the rates of patients achieving TR and TH, comparing three definitions of TH. In 137 Crohn's disease [CD] patients, the predictive value of TR and TH was investigated for the clinical and sonographic outcome at week 52.Within 12 weeks of treatment intensification, 65.6% [n = 118] of CD patients and 76.6% [n = 131] of ulcerative colitis [UC] patients showed a TR. Depending on the definition, 23.9-37.2% [n = 58/67/43] of CD patients and 45.0-61.4% [n = 90/105/77] of UC patients had TH at week 12. CD patients with TH were more likely to reach clinical remission at week 12 (odds ratio [OR] 3.33 [1.09-10.2]; p = 0.044) and a favourable sonographic outcome (OR 5.59 [1.97-15.8]; p = 0.001) at week 52 compared with patients without TH.IUS response and TH in a relevant proportion of patients suggests that IUS is a useful method to assess transmural inflammatory activity in daily clinical practice. TR and TH are predictive for the sonographic outcome at week 52.