Terminal Ileum Thickness During Maintenance Therapy Is a Predictive Marker of the Outcome of Infliximab Therapy in Crohn Disease

Factors correlated with transmural healing in patients with Crohn's disease in long-term clinical remission on anti-TNF medication

BACKGROUND & AIMS

Transmural healing is a long-term target for patients with Crohn's disease. Factors contributing to its promotion are poorly understood. This study assessed factors correlating with transmural healing based on intestinal ultrasound, in patients in long-term clinical remission on anti-TNF.

METHODS

68 consecutive Crohn's patients on adalimumab (50) or infliximab (18) therapy with clinical remission ≥1 year were recruited and assessed for clinical features, trough serum levels of anti-TNF and intestinal ultrasound findings. Univariate analysis and multivariate binary logistic regression analysis identified variables independently associated with bowel wall thickening behavior.

RESULTS

Sixty eight patients were in remission for a mean of 4.1 years. Thirty-six patients (52.9 %) showed anti-TNF trough levels below the normal threshold. Twenty-two patients (38.4 %) showed transmural healing, 32 (47.1 %) transmural response, and 26 (38.2 %) no treatment response. Transmural healing correlated with higher BMI and lower baseline bowel wall thickening; transmural response correlated with short Crohn's disease duration, high drug levels, and with non-stricturing phenotype. Treatment non-response correlated with lower BMI, lower drug levels, higher baseline bowel wall thickening, and stricturing phenotype.

CONCLUSIONS

Lack of transmural healing in stable remission Crohn's patients on anti-TNF therapy is multifactorial, mainly due to low anti-TNFs trough levels, development of strictures, and higher baseline bowel wall thickening at treatment initiation.

Prognostic role of intestinal ultrasound in Crohn’s disease

The majority of patients affected by Crohn’s disease (CD) develop a chronic condition with persistent inflammation and relapses that may cause progressive and irreversible damage to the bowel, resulting in stricturing or penetrating complications in around 50% of patients during the natural history of the disease. Surgery is frequently needed to treat complicated disease when pharmacological therapy failes, with a high risk of repeated operations in time. Intestinal ultrasound (IUS), a non-invasive, cost-effective, radiation free and reproducible method for the diagnosis and follow-up of CD, in expert hands, allow a precise assessment of all the disease manifestations: Bowel characteristics, retrodilation, wrapping fat, fistulas and abscesses. Moreover, IUS is able to assess bowel wall thickness, bowel wall stratification (echo-pattern), vascularization and elasticity, as well as mesenteric hypertrophy, lymph-nodes and mesenteric blood flow. Its role in the disease evaluation and behaviour description is well assessed in literature, but less is known about the potential space of IUS as predictor of prognostic factors suggesting response to a medical treatment or postoperative recurrence. The availability of a low cost exam as IUS, able to recognize which patients are more likely to respond to a specific therapy and which patients are at high risk of surgery or complications, could be a very useful instrument in the hands of IBD physician. The aim of this review is to present current evidence about the prognostic role that IUS can show in predicting response to treatment, disease progression, risk of surgery and risk of post-surgical recurrence in CD.

Transmural remission characterized by high biologic concentrations demonstrates better prognosis in Crohn's disease

BACKGROUND

The importance and pathophysiology of transmural healing in patients with Crohn's disease (CD) remains to be verified. We aimed to examine the association between serum concentrations of biologics and transmural remission evaluated via magnetic resonance enterography (MRE).

METHODS

We enrolled patients with CD who received maintenance biologics 1 year after induction and prospectively followed up for at least 1 year after baseline laboratory, endoscopic and MRE examination. We evaluated the relationship between baseline factors including the presence of transmural remission and patient prognosis, as well as between serum concentrations and transmural remission.

RESULTS

We included 134 patients. Of them, 65, 31, 27, and 11 patients received infliximab, adalimumab, ustekinumab, and vedolizumab, respectively. Those who achieved transmural remission showed a lower risk of hospitalization and surgery than those who did not achieve remission (P < 0.01). Adjusted hazard ratios of transmural remission for predicting hospitalization and surgery was 0.11 and 0.02, respectively, which was lower than that of clinical remission, biochemical remission, and endoscopic remission. Regarding serum concentrations, the median concentration was higher in patients with transmural remission than in patients with transmural activity for all agents (P < 0.01 for infliximab, P = 0.04 for adalimumab, P < 0.01 for ustekinumab, P = 0.08 for vedolizumab).

CONCLUSIONS

Transmural remission was the best predictor for prognosis in CD patients who received maintenance biologic therapy. High drug concentration levels were associated with transmural remission confirmed via MRE.

Predicting Mucosal Healing in Crohn's Disease: A Nomogram Model Developed from a Retrospective Cohort

Purpose

Mucosal healing (MH) has become a therapeutic end point for Crohn's disease (CD). The purpose of this study was to identify potential risk factors responsible for a lower probability of mucosal healing in CD. It also aimed to create and validate a noninvasive tool for predicting mucosal healing in CD to aid clinical decision-making.

Patients and Methods

We established a derivation cohort diagnosed with CD, in which endoscopic examination was performed before and after treatment at the First Affiliated Hospital of Nanjing Medical University between January 2010 and June 2021. Patient data including demographic and clinical characteristics and treatment details were collected. The achievement of mucosal healing (without ulceration on endoscopic examination) after treatment was the endpoint observed during follow-up. We performed logistic regression analysis to identify factors associated with mucosal healing. These factors were used to develop a model (CD mucosal healing prediction nomogram) to predict mucosal healing in CD. External validation was performed using a new cohort of 60 patients from the Second Affiliated Hospital of Soochow University between January 2012 and June 2021.

Results

A total of 331 patients were included in the derivation cohort. We found the following factors to be independently associated with mucosal healing after treatment: disease course <11 months, ulcer size <0.5 cm, Harvey-Bradshaw Index score <9, infliximab treatment, and non-exclusive use of 5-aminosalicylic acid. The model incorporating these factors achieved good discrimination, calibration, and clinical decision curve analysis results on internal validation (C-index: 0.788, 95% confidence interval [CI]: 0.74-0.84). The external validation cohort also demonstrated good discrimination (C-index: 0.785, 95% CI: 0.68-0.90) and calibration.

Conclusion

The CD mucosal healing prediction nomogram model demonstrated good reliability and validated. It can potentially be developed into a simple and clinically useful tool for predicting mucosal healing in CD.

Infliximab Trough Levels Are Associated With Transmural Sonographic Healing in Inflammatory Bowel Disease

BACKGROUND

Mucosal healing improves clinical outcomes in patients with inflammatory bowel disease (IBD) and is associated with higher infliximab trough levels (ITLs). Transmural healing, assessed by intestinal ultrasound (IUS), is emerging as an objective target in Crohn's disease (CD) and ulcerative colitis (UC). This study explores the correlation between maintenance ITLs and sonographic transmural healing.

METHODS

Patients on maintenance infliximab therapy were prospectively enrolled to undergo paired IUS examination and serum ITL. Infliximab trough levels were compared between patients with and without sonographic markers of inflammation using the Mann-Whitney U test.

RESULTS

A prospective cohort of 103 patients (51% male; 79 CD; 24 UC; median duration of disease 8 years) underwent IUS and serum ITL testing. Forty-one percent of CD and 66% of UC patients demonstrated sonographic healing (bowel wall thickening ≤3 mm with no increase in color Doppler signal). Crohn's disease patients with sonographic healing had higher median ITL compared with those with sonographic inflammation (4.8 μg/mL vs 3.1 μg/mL; P = .049). Additionally, the presence of hyperemia on Doppler was independently associated with lower ITL compared with those without hyperemia (2.1 μg/mL vs 4.2 μg/mL, respectively; P = .003). There was no significant association between ITL and other sonographic markers of inflammation. In UC, lower ITL was associated with hyperemia on Doppler imaging (P = .04). There was no association between ITL and sonographic healing or any other individual sonographic parameter of inflammation.

CONCLUSIONS

Lower maintenance infliximab levels are associated with sonographic parameters of inflammation in UC and CD. Further studies are needed to determine whether targeting higher infliximab levels can increase sonographic healing.

Role of Multiparametric Intestinal Ultrasound in the Evaluation of Response to Biologic Therapy in Adults with Crohn’s Disease

Crohn’s disease is one of the two most common types of inflammatory bowel disease. Current medical therapies are based on the use of glucocorticoids, exclusive enteral nutrition, immunosuppressors such as azathioprine and methotrexate, and biological agents such as infliximab, adalimumab, vedolizumab, or ustekinumab. International guidelines suggest regular disease assessment and surveillance through objective instruments to adjust and personalize the therapy, reducing the overall rates of hospitalization and surgery. Although endoscopy represents the gold-standard for surveillance, its frequent use is strongly bordered by associated risks and costs. Consequently, alternative non-invasive tools to objectify disease activity and rule active inflammation out are emerging. Alongside laboratory exams and computed tomography or magnetic resonance enterography, intestinal ultrasonography (IUS) shows to be a valid choice to assess transmural inflammation and to detect transmural healing, defined as bowel wall thickness normalization, no hypervascularization, normal stratification, and no creeping fat. Compared to magnetic resonance imaging (MRI) or computed tomography, CT scan, IUS is cheaper and more widespread, with very similar accuracy. Furthermore, share wave elastography, color Doppler, and contrast-enhanced ultrasonography (CEUS) succeed in amplifying the capacity to determine the disease location, disease activity, and complications. This review aimed to discuss the role of standard and novel ultrasound techniques such as CEUS, SICUS, or share wave elastography in adults with Crohn’s disease, mainly for therapeutic monitoring and follow-up.

Clinical implication of radiologic complete remission on Crohn's Disease: Compared with endoscopic remission

OBJECTIVES

To determine the clinical implications of radiologic complete remission (CR) in Crohn's disease (CD) evaluated by computed tomography (CT) or magnetic resonance enterography (MRE) in comparison with endoscopic CR.

METHODS

Twenty-five CD patients who achieved endoscopic CR after medical treatment were retrospectively enrolled in this study. All patients underwent ileocolonoscopy, CT, or MRE at baseline, at the time of endoscopic CR, and during follow-up. Two radiologists assessed the mural and perienteric abnormalities on pre- and post-treatment CT or MRE in consensus. Patients were divided into radiologic CR and non-CR groups at the time of endoscopic CR. CD recurrence during subsequent follow-up periods was evaluated using clinical, laboratory, and CT/MRI findings. Statistical analysis was performed to assess whether there were significant differences in patient outcomes between the groups.

RESULTS

At the time of endoscopic CR, nine patients (mean age, 36.6 years) showed normalization of all radiologic features and were designated as the radiologic CR group. However, 16 patients (mean age: 32.9 years) showed residual CT/MRE abnormalities, suggesting persistent active inflammation, and were designated as the radiologic non-CR group. During follow-up, there was a significant difference between the groups regarding clinical outcomes (deep CR, 8/9 vs 5/16, P = 0.011; CD recurrence, 1/9 vs 14/16, P < 0.001). The mean fecal calprotectin level was significantly lower in the radiologic CR group (287.5 ug/g) than in the non-CR group (652.4 ug/g) (P = 0.023).

CONCLUSIONS

Radiologic CR can represent a better therapeutic endpoint in CD, showing superiority over endoscopic CR in predicting both clinical and biochemical outcomes.

Application of transabdominal ultrasound in Crohn's disease

Crohn's disease (CD), a chronic nonspecific intestinal inflammatory disorder of uncertain origin, is collectively referred to as inflammatory bowel disease with ulcerative colitis. In recent years, with the increasing incidence of CD, a greater demand has been put forward for disease diagnosis and inflammatory activity monitoring. With the development of ultrasound technology, transabdominal ultrasound has become more relevant for the diagnosis and follow-up of CD, providing an effective non-invasive examination tool for patients. This review summarizes several transabdominal ultrasound modalities and associated techniques that are presently being developed and utilized in clinical practice, describes the ultrasound manifestations of CD, and discusses the value and prospect of transabdominal ultrasonography in CD.

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

BACKGROUND AND AIMS

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Point-of-care Intestinal Ultrasound in IBD Patients: Disease Management and Diagnostic Yield in a Real-world Cohort and Proposal of a Point-of-care Algorithm

INTRODUCTION

Intestinal ultrasound [IUS] is useful for assessment of inflammation, complications, and treatment follow-up in inflammatory bowel disease [IBD] patients. We aimed to study outcomes and impact on disease management for point-of-care [POC] IUS in IBD patients.

METHODS

Two patient cohorts undergoing POC IUS [January 2016-July 2018 and October 2019-December 2019] were included retrospectively. Disease management after IUS was analysed and IUS outcomes were compared with symptoms, biomarkers, and additional imaging within 8 weeks from IUS. To study differences in use of IUS over time, cohorts were compared.

RESULTS

In total, 345 examinations (280 in Crohn's disease [CD]/65 in ulcerative colitis [UC]) were performed. Present inflammation on IUS was comparable between symptomatic and asymptomatic CD [67.6% vs 60.5%; p = 0.291]. In 60%, IUS had impact on disease management with change in medication in 47.8%. Additional endoscopy/magnetic resonance imaging [MRI] was planned after 32.8% examinations, showing good correlation with IUS in 86.3% [ρ = 0.70, p <0.0001] and 80.0% [ρ = 0.75, p <0.0001] of cases, respectively. Faecal calprotectin was higher in active versus inactive disease on IUS [664 µg/g vs 79 µg/g; p <0.001]. Over the years, IUS was performed more frequently to monitor treatment response and the use of MRI was reduced within the cohort.

CONCLUSIONS

POC IUS affects clinical decision making and could detect preclinical relapse in CD patients, with potential to reduce additional endoscopy or MRI. In addition, the paradigm expands towards monitoring treatment and close follow-up for IUS. Based on our results, we propose a POC IUS algorithm for follow-up of IBD patients.

A literature review on large intestinal hyperelastic constitutive modeling

Impacts, traumas and strokes are spontaneously life-threatening, but chronic symptoms strangle patient every day. Colorectal tissue mechanics in such chronic situations not only regulates the physio-psychological well-being of the patient, but also confirms the level of comfort and post-operative clinical outcomes. Numerous uniaxial and multiaxial tensile experiments on healthy and affected samples have evidenced significant differences in tissue mechanical behavior and strong colorectal anisotropy across each layer in thickness direction and along the length. Furthermore, this study reviewed various forms of passive constitutive models for the highly fibrous colorectal tissue ranging from the simplest linearly elastic and the conventional isotropic hyperelastic to the most sophisticated second harmonic generation image based anisotropic mathematical formulation. Under large deformation, the isotropic description of tissue mechanics is unequivocally ineffective which demands a microstructural based tissue definition. Therefore, the information collected in this review paper would present the current state-of-the-art in colorectal biomechanics and profoundly serve as updated computational resources to develop a sophisticated characterization of colorectal tissues.

Bowel Ultrasound in Inflammatory Bowel Disease: How Far in the Grayscale?

Bowel ultrasound (BUS) is a non-invasive and accurate technique for assessing activity, extension of disease, and complications in inflammatory bowel diseases. The main advantages of BUS are its safety, reproducibility, and low costs. Ancillary technologies of BUS (i.e., color Doppler and wave elastography) could broaden the diagnostic power of BUS, allowing one to distinguish between inflammation and fibrosis. Considering the costs and invasiveness of colonoscopy and magnetic resonance, BUS appears as a fast, safe, and accurate technique. The objective measures of disease allow one to make clinical decisions, such as optimization, switch, or swap of therapy. Previous studies reported a sensitivity and a specificity of more than 90% compared to endoscopy and magnetic resonance. Lastly, transperineal ultrasound (TPUS) is a promising approach for the evaluation of perianal disease in Crohn’s disease (CD) and disease activity in patients with ulcerative proctitis or pouchitis. Bowel ultrasound is being incorporated in the algorithm of managing inflammatory bowel diseases. Transmural healing evaluated through ultrasonography is emerging as a complementary target for disease treatment. In this review, we aimed to summarize and discuss the current evidence on BUS in the management of inflammatory bowel diseases and to address the challenges of a full validation of this technique.

Relevance of monitoring transmural disease activity in patients with Crohn's disease: current status and future perspectives

Treatment targets of inflammatory bowel diseases (IBD), ulcerative colitis (UC) and Crohn's disease (CD) have evolved over the last decade. Goals of therapy consisting of symptom control and steroid sparing have shifted to control of disease activity with endoscopic remission being an important endpoint. Unfortunately, this requires ileocolonoscopy, an invasive procedure. Biomarkers [C-reactive protein (CRP) and fecal calprotectin (FCP)] have emerged as surrogates for endoscopic remission and disease activity, but also have limitations. Despite this evolution, we must not lose sight that CD involves transmural inflammation, not fully appreciated with ileocolonoscopy. Therefore, transmural assessment of disease activity by cross-sectional imaging, in particular with magnetic resonance enterography (MRE) and intestinal ultrasonography (IUS), is vital to fully understand disease control. Bowel-wall thickness (BWT) is the cornerstone in assessment of transmural inflammation and BWT normalization, with or without bloodflow normalization, the key element demonstrating resolution of transmural inflammation, namely transmural healing (TH) or transmural remission (TR). In small studies, achievement of TR has been associated with improved long-term clinical outcomes, including reduced hospitalization, surgery, escalation of treatment, and a decrease in clinical relapse over endoscopic remission alone. This review will focus on the existing literature investigating the concept of TR or residual transmural disease and its relation to other existing treatment targets. Current data suggest that TR may be the next logical step in the evolution of treatment targets.