Intraluminal oxygen can keep small bowel mucosa intact in a segmental ischemia model.

Intestinal preservation for transplantation is accompanied by hypoperfusion with long periods of ischemia with total blood cessation and absolute withdrawal of oxygen leading to structural damage. The application of intraluminal oxygen has been successfully tested in small-animal series during storage and transport of the organ but have been so far clinically unrelatable. In this study, we tested whether a simple and clinically approachable method of intraluminal oxygen application could prevent ischemic damage in a large animal model, during warm ischemia time. We utilised a local no-flow ischemia model of the small intestine in pigs. A low-flow and high-pressure intraluminal oxygen deliverance system was applied in 6 pigs and 6 pigs served as a control group. Mucosal histopathology, hypoxia and barrier markers were evaluated after two hours of no-flow conditions, in both treatment and sham groups, and in healthy tissue. Macro- and microscopically, the luminal oxygen delivered treatment group showed preserved small bowel's appearance, viability, and mucosal integrity. A gradual deterioration of histopathology and barrier markers and increase in hypoxia-inducible factor 1-α expression towards the sites most distant from the oxygen application was observed. Intraluminal low-flow, high oxygen delivery can preserve the intestinal mucosa during total ischemia of the small intestine. This finding can be incorporated in methods to overcome small bowel ischemia and improve intestinal preservation for transplantation.

Factors influencing endoscopic estimation of colon polyp size in a colon model.

BACKGROUND/AIMS: Colorectal polyps are removed to prevent progression to colorectal cancer. Polyp size is an important factor for risk stratification of malignant transformation. Endoscopic size estimation correlates poorly with pathological reports and several factors have been suggested to influence size estimation. We aimed to gain insight into the factors influencing endoscopic polyp size estimation. METHODS: Images of polyps in an artificial model were obtained at 1, 3, and 5 cm from the colonoscope's tip. Participants were asked to estimate the diameter and volume of each polyp. RESULTS: Fifteen endoscopists from three large-volume centers participated in this study. With an intraclass correlation coefficient of 0.66 (95% confidence interval [CI], 0.62-0.71) for diameter and 0.56 (95% CI, 0.50-0.62) for volume. Polyp size estimated at 3 cm from the colonoscope's tip yielded the best results. A lower distance between the tip and the polyp was associated with a larger estimated polyp size. CONCLUSION: Correct endoscopic estimation of polyp size remains challenging. This finding can affect size estimation skills and future training programs for endoscopists.

Diagnostic Accuracy of the Combination of Clinical Symptoms and CT or MR Angiography in Patients With Chronic Gastrointestinal Ischemia.

BACKGROUND: No golden diagnostic standard is available to diagnose chronic gastrointestinal ischemia (CGI). GOALS: We aimed to establish an accurate prediction model for CGI, based on clinical symptoms and radiologic evaluation of the amount of stenosis in the celiac artery (CA) and superior mesenteric artery (SMA) by means of computed tomography-angiography or magnetic resonance (MR)-angiography. STUDY: We prospectively included 436 consecutive patients with clinical suspicion of CGI in a tertiary referral center. Predictors for CGI were obtained by comparing clinical parameters to the diagnosis of CGI. Multivariable logistic regression was used to combine the strongest predictors in a model. A score chart based on the prediction model was provided to calculate the risk of CGI. RESULTS: CGI was present in 171/436 (39%) patients (67 y; range, 54 to 74 y; 27% male). Strongest predictors for CGI were female gender [odds ratio (OR)=1.44; 95% confidence interval (CI), 0.85-2.43], weight loss (OR=1.63, 95% CI, 0.98-2.72), concomitant cardiovascular disease (OR=1.70, 95% CI, 1.04-2.78), duration of symptoms (OR=0.88, 95% CI, 0.79-0.99), and stenosis of CA and SMA (50% to 70% stenosis CA: OR=1.33, 95% CI, 0.56-3.19; >70% stenosis CA: OR=5.79, 95% CI, 3.42-9.81; 50% to 70% stenosis SMA: OR=3.21, 95% CI, 0.81-12.74; >70% stenosis SMA: OR=4.39, 95% CI, 2.30-8.41). A model based on clinical symptoms alone showed limited discriminative ability for diagnosing CGI (c-statistic 0.62). Adding radiologic imaging of the mesenteric arteries improved the discriminative ability (c-statistic 0.79). CONCLUSIONS: Clinical symptoms alone are insufficient to predict the risk of CGI. Radiologic evaluation of the mesenteric arteries is essential. This tool may be useful for clinicians to assess the risk of CGI and to decide whether further diagnostic work-up for CGI is needed.

Use of visible light spectroscopy to diagnose chronic gastrointestinal ischemia and predict response to treatment.

BACKGROUND & AIMS: Chronic gastrointestinal ischemia (CGI) is more common than previously thought. Visible light spectroscopy (VLS) allows for noninvasive measurements of mucosal capillary hemoglobin oxygen saturation during endoscopy. We evaluated the response of patients with occlusive CGI to treatment after evaluation by radiologic imaging of the vasculature and VLS. We also identified factors associated with response to treatment in these patients. METHODS: In a prospective study, we collected data from 212 patients referred for evaluation of suspected CGI from November 2008 through January 2011. Patients underwent an extensive evaluation that included visualization of gastrointestinal arteries and assessments of mucosal perfusion by means of VLS. Treatment response was evaluated in patients with occlusive CGI. Factors associated with response to therapy were assessed by using multivariate logistic regression analysis. RESULTS: Occlusive CGI was diagnosed in 107 patients (50%); 96 were offered treatment (90%). After median follow-up period of 13 months, data on treatment response were available from 89 patients (93%); 62 patients had a sustained response (70%). Weight loss before treatment (odds ratio [OR], 1.93), presence of an abdominal bruit (OR, 2.36), and corpus mucosal saturation level <56% (OR, 4.84) were the strongest predictors of a positive response to treatment. CONCLUSIONS: Treatment of CGI, diagnosed by a multimodal approach, provides a substantial long-term rate of response (70% in 13 months). Weight loss, abdominal bruit, and low corpus mucosal saturation identify patients most likely to respond to treatment. Multiple techniques should therefore be used to assess patients with CGI, including VLS measurements, to detect mucosal hypoxia.

Combining radiological imaging and gastrointestinal tonometry: a minimal invasive and useful approach for the workup of chronic gastrointestinal ischemia.

BACKGROUND: The established approach for patients suspected of chronic gastrointestinal ischemia (CGI) includes assessment of medical history, vascular imaging, such as by digital subtraction angiography, and, more recently, computed tomography angiography (CTA) or magnetic resonance angiography. Mucosal perfusion assessment techniques have recently been shown to be of additional diagnostic value, including visible light spectroscopy and gastric exercise tonometry. Gastric exercise tonometry, however, is cumbersome and impossible to perform in a considerable proportion of patients. An alternative approach is provided by 24 h gastrointestinal tonometry (TM). We challenged the use of TM in combination with CTA as an alternative approach to evaluate patients suspected of CGI. METHODS: Patients referred for suspected CGI were prospectively evaluated using CTA and TM, and discussed in a multidisciplinary team, where a consensus diagnosis was made. CGI patients were offered therapy. Persistent symptom relief after adequate therapy during follow-up was used as the 'gold standard' and was defined as a definitive diagnosis of CGI. RESULTS: In 31 months, 186 patients were included (men 69, mean age 63 years). A consensus diagnosis of CGI was made in 128 (69%) patients: 94 with occlusive and 34 with nonocclusive CGI. After a median follow-up of 21 months after a therapeutical intervention, 91% of the CGI patients were free from symptoms. CONCLUSION: In patients clinically suspected of CGI, the combination of CTA and TM provides a minimally invasive, reliable diagnostic approach, which seems to be very useful in clinical practice and to have an outcome similar to the established diagnostic workup.

Patient burden and patient preference: comparing magnetic resonance enteroclysis, capsule endoscopy and balloon-assisted enteroscopy.

BACKGROUND AND AIM: We aimed to prospectively determine patient burden and patient preference for magnetic resonance enteroclysis, capsule endoscopy and balloon-assisted enteroscopy in patients with suspected or known Crohn's disease (CD) or occult gastrointestinal bleeding (OGIB). METHODS: Consecutive consenting patients with CD or OGIB underwent magnetic resonance enteroclysis, capsule endoscopy and balloon-assisted enteroscopy. Capsule endoscopy was only performed if magnetic resonance enteroclysis showed no high-grade small bowel stenosis. Patient preference and burden was evaluated by means of standardized questionnaires at five moments in time. RESULTS: From January 2007 until March 2009, 76 patients were included (M/F 31/45; mean age 46.9 years; range 20.0-78.4 years): 38 patients with OGIB and 38 with suspected or known CD. Seventeen patients did not undergo capsule endoscopy because of high-grade stenosis. Ninety-five percent (344/363) of the questionnaires were suitable for evaluation. Capsule endoscopy was significantly favored over magnetic resonance enteroclysis and balloon-assisted enteroscopy with respect to bowel preparation, swallowing of the capsule (compared to insertion of the tube/scope), burden of the entire examination, duration and accordance with the pre-study information. Capsule endoscopy and magnetic resonance enteroclysis were significantly preferred over balloon-assisted enteroscopy for clarity of explanation of the examination, and magnetic resonance enteroclysis was significantly preferred over balloon-assisted enteroscopy for bowel preparation, painfulness and burden of the entire examination. Balloon-assisted enteroscopy was significantly favored over magnetic resonance enteroclysis for insertion of the scope and procedure duration. Pre- and post-study the order of preference was capsule endoscopy, magnetic resonance enteroclysis and balloon-assisted enteroscopy. CONCLUSION: Capsule endoscopy was preferred to magnetic resonance enteroclysis and balloon-assisted enteroscopy; it also had the lowest burden. Magnetic resonance enteroclysis was preferred over balloon-assisted enteroscopy for clarity of explanation of the examination, bowel preparation, painfulness and burden of the entire examination, and balloon-assisted enteroscopy over magnetic resonance enteroclysis for scope insertion and study duration.

Hyperamylasemia and pancreatitis following spiral enteroscopy.

BACKGROUND: Acute pancreatitis is a significant potential complication with double-balloon enteroscopy. Hyperamylasemia is frequently observed after both double-balloon enteroscopy and single-balloon enteroscopy but often without associated pancreatitis. Whether the same phenomenon occurs with spiral enteroscopy is currently unknown. AIMS: To determine the incidence of pancreatitis and hyperamylasemia following spiral enteroscopy. METHODS: A prospective cohort study of consecutive patients undergoing proximal spiral enteroscopy was conducted. Serum amylase levels were measured immediately before and following the procedure, combined with observation for clinical signs of pancreatitis. RESULTS: A total of 32 patients underwent proximal spiral enteroscopy, with a mean total procedure time of 51 min (range 30 min to 100 min) and mean depth of insertion of 240 cm (range 50 cm to 350 cm). The diagnostic yield was 50%, with 31% of all procedures being therapeutic. While no patients exhibited signs that raised suspicion of pancreatitis, hyperamylasemia was common (20%). Hyperamylasemia was not significantly associated with procedure duration or depth of insertion but was linked to patients with Peutz-Jeghers syndrome and with the use of propofol sedation, suggesting that it may be more common in difficult cases. CONCLUSIONS: Postprocedural hyperamylasemia occurred frequently with proximal spiral enteroscopy, while no associated pancreatitis was observed. This finding suggests that hyperamylasemia may not necessarily reflect pancreatic injury nor portend a risk for pancreatitis.

Patients with chronic gastrointestinal ischemia have a higher cardiovascular disease risk and mortality.

OBJECTIVES: We determined the prevalence of classical risk factors for atherosclerosis and mortality risk in patients with CGI. METHODS: A case-control study was conducted. Patients referred with suspected CGI underwent a standard work-up including risk factors for atherosclerosis, radiological imaging of abdominal vessels and tonometry. Cases were patients with confirmed atherosclerotic CGI. Controls were healthy subjects previously not known with CGI. The mortality risk was calculated as standardized mortality ratio derived from observed mortality, and was estimated with ten-year risk of death using SCORE and PREDICT. RESULTS: Between 2006 and 2009, 195 patients were evaluated for suspected CGI. After a median follow-up of 19 months, atherosclerotic CGI was diagnosed in 68 patients. Controls consisted of 132 subjects. Female gender, diabetes, hypercholesterolemia, a personal and family history of cardiovascular disease (CVD), and current smoking are highly associated with CGI. After adjustment, female gender (OR 2.14 95% CI 1.05-4.36), diabetes (OR 5.59, 95% CI 1.95-16.01), current smoking (OR 5.78, 95% CI 2.27-14.72), and history of CVD (OR 21.61, 95% CI 8.40-55.55) remained significant. CGI patients >55 years had a higher median ten-year risk of death (15% vs. 5%, P = 0.001) compared to controls. During follow-up of 116 person-years, standardized mortality rate was higher in CGI patients (3.55; 95% CI 1.70-6.52). CONCLUSIONS: Patients with atherosclerotic CGI have an increased estimated CVD risk, and severe excess mortality. Secondary cardiovascular prevention therapy should be advocated in patients with CGI.

Small bowel diagnostics: current place of small bowel endoscopy.

The small intestine has been difficult to examine by traditional endoscopic and radiologic techniques. Until the end of the last century, the small bowel follow through was the primary diagnostic tool for suspected small bowel disease. In recent years capsule endoscopy, deep enteroscopy using balloon-assisted or spiral techniques, computerized tomography and magnetic resonance enteroclysis or enterography have facilitated the diagnosis, monitoring, and management of patients with small bowel diseases. These technologies are complementary, each with its advantages and limitations. In the present article, we will discuss the different options and indications for modern diagnostic methods for visualization of the small bowel. We also try to provide a clinical rationale for the use of these different diagnostic options in less established, newly emerging, indications for small bowel evaluation.

Single-balloon enteroscopy, magnetic resonance enterography, and abdominal US useful for evaluation of small-bowel disease in children with (suspected) Crohn's disease.

BACKGROUND: The usefulness of single-balloon enteroscopy (SBE) has not been evaluated in children with known or suspected Crohn's disease (CD). OBJECTIVE: The objectives of this study are to evaluate the diagnostic yield of SBE for pediatric CD by comparing it with US and magnetic resonance enterography (MRE). DESIGN: Single-center prospective study. SETTING: Tertiary-care referral hospital. PATIENTS: Between February 2009 and April 2010, 20 pediatric patients (ages 8-18 years) with suspected inflammatory bowel disease (IBD) or with a previous diagnosis of CD with suspected persistent small-bowel disease were enrolled. INTERVENTIONS: All patients underwent proximal and distal SBE, 17 patients also underwent US combined with Doppler flow measurements, and 18 underwent MRE. MAIN OUTCOME MEASUREMENTS: The findings of US with Doppler flow measurements and MRE were compared with those with SBE. RESULTS: The mean patient age was 15.0 years (range 11.3-18 years, 70% male). Of 14 patients with suspected IBD, 8 had a diagnosis of CD made after SBE. Activity in the small bowel was found in 14 patients (70%) with both suspected and previously diagnosed CD. Twelve patients (60%) had small-bowel disease that was out of reach of conventional endoscopy. Three patients (15%) had small-bowel activity solely in the jejunum, which was not detected by either MRE or US. LIMITATIONS: Single-center study with small sample size. CONCLUSIONS: SBE can be used in children to accurately assess small-bowel disease and CD. Small-bowel activity may be identified by SBE in some patients in whom it may not be apparent despite use of conventional upper endoscopy, ileocolonoscopy, US with Doppler flow measurements, or MRE.

Small bowel Crohn's disease: MR enteroclysis and capsule endoscopy compared to balloon-assisted enteroscopy.

New modalities are available to visualize the small bowel in patients with Crohn's disease (CD). The aim of this study was to compare the diagnostic yield of magnetic resonance enteroclysis (MRE) and capsule endoscopy (CE) to balloon-assisted enteroscopy (BAE) in patients with suspected or established CD of the small bowel. Consecutive, consenting patients first underwent MRE followed by CE and BAE. Patients with high-grade stenosis at MRE did not undergo CE. Reference standard for small bowel CD activity was a combination of BAE and an expert panel consensus diagnosis. Analysis included 38 patients, 27 (71%) females, mean age 36 (20-74) years, with suspected (n = 20) or established (n = 18) small bowel CD: 16 (42%) were diagnosed with active CD, and 13 (34%) by MRE with suspected high-grade stenosis, who consequently did not undergo CE. The reference standard defined high-grade stenosis in 10 (26%) patients. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value of MRE and CE for small bowel CD activity were 73 and 57%, 90 and 89%, 88 and 67%, and 78 and 84%, respectively. CE was complicated by capsule retention in one patient. MRE has a higher sensitivity and PPV than CE in small bowel CD. The use of CE is considerably limited by the high prevalence of stenotic lesions in these patients.

Retrograde double balloon enteroscopy: comparing performance of solely retrograde versus combined same-day anterograde and retrograde procedure.

OBJECTIVE: Retrograde double balloon enteroscopy (DBE) is important for evaluating the distal small bowel, but it is more challenging compared to the oral route. Optimizing small bowel insertion may enhance the diagnostic utility of the examination. We sought to determine if insertion depths achieved with retrograde DBE when performed as an isolated procedure differed significantly from when performed immediately following anterograde DBE. MATERIAL AND METHODS: A retrospective analysis was conducted of all retrograde DBE procedures performed at our center with comparisons made between "distal-only" DBE without preceding anterograde DBE and "combined" DBE after a prior same-day anterograde DBE. RESULTS: Two hundred ninety retrograde DBE procedures were performed in 264 patients over 5 years. Success of terminal ileal intubation exceeded 95%. The mean insertion depth into the distal small bowel differed significantly with 112 cm (95% CI 95-129) in the "distal-only" group and 92 cm (95% CI 85-98) in the "combined" group (p = 0.01), with a trend toward a corresponding increased diagnostic yield of 48% versus 37%, respectively (p = 0.15). Multivariate regression analysis identified both insertion route strategy (distal-only > combined; p = 0.01) and type of DBE endoscope (diagnostic > therapeutic; p = 0.02) as significant predictors of retrograde insertion depth. CONCLUSIONS: The insertion depth of retrograde DBE is significantly greater when carried out as a separate distal procedure and not in combination with a preceding anterograde DBE, and when performed using a diagnostic as opposed to the therapeutic DBE endoscope. This increased retrograde depth of insertion may be associated with an increased diagnostic yield.

Endoscopic visible light spectroscopy: a new, minimally invasive technique to diagnose chronic GI ischemia.

BACKGROUND: The diagnosis of chronic GI ischemia (CGI) remains a clinical challenge. Currently, there is no single simple test with high sensitivity available. Visible light spectroscopy (VLS) is a new technique that noninvasively measures mucosal oxygen saturation during endoscopy. OBJECTIVE: To determine the diagnostic accuracy of VLS for the detection of ischemia in a large cohort of patients. DESIGN: Prospective study, with adherence to the Standards for Reporting of Diagnostic Accuracy. SETTING: Tertiary referral center. PATIENTS: Consecutive patients referred for evaluation of possible CGI. INTERVENTIONS: Patients underwent VLS along with the standard workup consisting of evaluation of symptoms, GI tonometry, and abdominal CT or magnetic resonance angiography. MAIN OUTCOME MEASUREMENTS: VLS measurements and the diagnosis of CGI as established with the standard workup. RESULTS: In 16 months, 121 patients were included: 80 in a training data set and 41 patients in a validation data set. CGI was diagnosed in 89 patients (74%). VLS cutoff values were determined based on the diagnosis of CGI and applied in the validation data set, and the results were compared with the criterion standard, resulting in a sensitivity and specificity of VLS of 90% and 60%, respectively. Repeated VLS measurements showed improvement in 80% of CGI patients after successful treatment. LIMITATIONS: Single-center study; only 43% of patients had repeated VLS measurements after treatment. CONCLUSIONS: VLS during upper endoscopy is a promising easy-to-perform and minimally invasive technique to detect mucosal hypoxemia in patients clinically suspected of having CGI, showing excellent correlation with the established ischemia workup.

Double balloon enteroscopy and capsule endoscopy for obscure gastrointestinal bleeding: an updated meta-analysis.

BACKGROUND AND AIM: Uncertainty remains about the best test to evaluate patients with obscure gastrointestinal bleeding (OGIB). Previous meta-analyses demonstrated similar diagnostic yields with capsule endoscopy (CE) and double balloon enteroscopy (DBE) but relied primarily on data from abstracts and were not limited to bleeding patients. Many studies have since been published. Therefore, we performed a new meta-analysis comparing CE and DBE focused specifically on OGIB. METHODS: A comprehensive literature search was performed of comparative studies using both CE and DBE in patients with OGIB. Data were extracted and analyzed to determine the weighted pooled diagnostic yields of each method and the odds ratio for the successful localization of a bleeding source. RESULTS: Ten eligible studies were identified. The pooled diagnostic yield for CE was 62% (95% confidence interval [CI] 47.3-76.1) and for DBE was 56% (95% CI 48.9-62.1), with an odds ratio for CE compared with DBE of 1.39 (95% CI 0.88-2.20; P = 0.16). Subgroup analysis demonstrated the yield for DBE performed after a previously positive CE was 75.0% (95% CI 60.1-90.0), with the odds ratio for successful diagnosis with DBE after a positive CE compared with DBE in all patients of 1.79 (95% CI 1.09-2.96; P = 0.02). In contrast, the yield for DBE after a previously negative CE was only 27.5% (95% CI 16.7-37.8). CONCLUSIONS: Capsule endoscopy and double balloon enteroscopy provide similar diagnostic yields in patients with OGIB. However, the diagnostic yield of DBE is significantly higher when performed in patients with a positive CE.

Radiological imaging and gastrointestinal tonometry add value in diagnosis of chronic gastrointestinal ischemia.

BACKGROUND & AIMS: The diagnosis of chronic gastrointestinal ischemia (CGI) remains a clinical challenge. We aimed to assess the diagnostic value of clinical features, visualization of the gastrointestinal arteries, and evaluation of mucosal perfusion in patients clinically suspected of CGI. METHODS: A total of 186 patients referred for suspicion of CGI were prospectively included and followed up. All patients had an extensive diagnostic work-up, including visualization of the gastrointestinal arteries with computed tomography, magnetic resonance, or conventional angiography, and mucosal perfusion with tonometry. The reference standard for CGI was persistent clinical response after adequate therapy. The diagnostic value of individual and combined tests was assessed with multivariable logistic regression analysis. RESULTS: A total of 116 (62%) patients were diagnosed with CGI. In a multivariable model solely based on clinical features, the strongest predictors for CGI were the presence of postprandial pain, weight loss per month in kilograms, concomitant cardiovascular disease, and presence of an abdominal bruit. However, this model showed limited discriminative ability for the presence or absence of CGI (c-statistic, 0.62). Adding radiologic imaging to the prediction model improved the discriminative ability substantially (c-statistic, 0.81). Adding tonometry to the prediction model further improved the discriminative ability of the model (c-statistic, 0.90). The combination of clinical features and tonometry with a c-statistic of 0.88 approximated the discriminative ability of the latter model. CONCLUSIONS: Clinical features alone have a limited value to assess CGI correctly. Visualization of the gastrointestinal arteries and evaluation of mucosal perfusion substantially improve the diagnosis of CGI. The strongest diagnostic contribution comes from mucosal perfusion assessment.

Chronic gastrointestinal ischaemia: shifting paradigms.

Chronic gastrointestinal ischaemia (CGI) is generally considered to be a rare disease entity. The majority of patients with CGI are only diagnosed after a long period of slowly progressive abdominal symptoms, in some cases with impressive weight loss. These patients may have a broad range of clinical signs and quite often undergo repeated extensive evaluation of their symptoms with negative outcome. The classical triad of symptoms, also known as 'abdominal angina', is defined as the combination of postprandial pain, weight loss due to fear of pain after eating, and an abdominal bruit during physical examination. Recent studies have shed new lights on these long unchallenged concepts. These studies first showed that CGI is more prevalent than previously thought and can occur in patients with both single- and multi-vessel disease. Second, the disease presents with a much wider range in symptoms, and only a minority of patients present with the classical triad. Third, long-term positive outcomes can be achieved after endovascular or surgical revascularisation therapy in large proportion of patients. This knowledge results from a combination of clinical research by dedicated focus groups, the current widespread availability of new imaging techniques such as CT-angiography, the development of new functional tests for assessment of mucosal perfusion, and the evolution of endovascular stenting options. Clinicians diagnosing and treating patients with acute and chronic abdominal conditions have to be aware of these new developments. We therefore here review the new insights on CGI with a focus on epidemiology, pathophysiology, current diagnostics and treatment.

Serum markers and intestinal mucosal injury in chronic gastrointestinal ischemia.

BACKGROUND: Diagnosing chronic gastrointestinal ischemia (CGI) is a challenging problem in clinical practice. Serum markers for CGI would be of great diagnostic value as a non-invasive test method. AIMS: This study investigated serum markers in patients with well-defined ischemia. Furthermore, intestinal mucosal injury was also evaluated in CGI patients. METHODS: Consecutive patients suspected of CGI were prospectively enrolled and underwent a diagnostic work-up consisting of gastrointestinal tonometry and either CT or MR angiography. Blood samples for analysis of intestinal fatty acid-binding protein (I-FABP), D-dimer, lactate dehydrogenase (LDH), leucocyte counts, C-reactive protein (CRP), and L-lactate were drawn before and after a standard meal. Intestinal mucosal injury was assessed with glutamine, citrulline and arginine in blood samples and compared to a sugar absorption test (SAT). Test reproducibility was validated in healthy subjects. RESULTS: Forty patients and nine healthy subjects were included. Ischemia was diagnosed in 32 patients (80%). I-FABP, leucocyte counts, LDH, CRP, glutamine, citrulline, arginine and SAT levels did not differ between patients with and without ischemia. L-lactate concentration showed a significant elevation in ischemia patients as compared to non-ischemia patients. In ischemia patients, D-dimer levels showed a significant elevation postprandially as compared to D-dimer levels at baseline. However, these ischemia patients did not show intestinal mucosal injury. CONCLUSIONS: I-FABP, leucocyte counts, LDH and CRP levels are not clinically useful for the diagnosis of CGI. However, postprandial rises in L-lactate and D-dimer serum levels can serve as non-invasive indicators of CGI.

Histological changes in patients with chronic upper gastrointestinal ischaemia.

AIMS: Diagnosing chronic upper gastrointestinal ischaemia (CUGI) remains a challenge in clinical practice. Histological examination of biopsy material currently plays no role in the diagnosis of transient CUGI, as little is known about gastrointestinal histology in these patients. The aim of this study was to investigate upper gastrointestinal histology in patients with well-defined CUGI. METHODS AND RESULTS: Consecutive patients suspected of CUGI were included prospectively and underwent a diagnostic work-up existing of upper endoscopy, gastrointestinal tonometry and computed tomography (CT) or magnetic resonance (MR) angiography. Results were discussed in a multidisciplinary team and a consensus diagnosis was made. Endoscopic biopsy samples were taken from the descending duodenum, gastric antrum and corpus, and scored using the Sydney, Vienna, Chiu, Marsh and Operative Link for Gastritis Assessment (OLGA) classifications. Gastropathy was scored present or absent. Seventy-nine patients were analysed in 8months. CUGI was diagnosed in 41 patients (52%): 36 males, mean age 60 (17-86) years. Prevalence of gastropathy was significantly higher in patients with ischaemia (P=0.025). No other differences were found between patients with and without ischaemia. CONCLUSIONS: Histological examination of biopsy samples plays no definitive role in diagnosing CUGI, but the presence of histological signs of reactive gastropathy can be used to support the clinical diagnosis of ischaemia.

Single-balloon-assisted colonoscopy in patients with previously failed colonoscopy.

BACKGROUND: Despite advances in training and equipment, complete colonoscopy fails, even in experienced hands, in up to 10% of cases. Double-balloon endoscopy (DBE) has been successfully used to complete colonoscopy in these patients. Single-balloon endoscopy (SBE) has become established for small-bowel enteroscopy. However, it has yet to be studied for use in colonoscopy. OBJECTIVE: To assess the efficacy, performance, and safety of single-balloon colonoscopy. DESIGN: Prospective cohort study. SETTING: Academic tertiary referral center. PATIENTS: Patients with previously failed conventional colonoscopy. RESULTS: 23 single-balloon colonoscopy procedures were performed in 22 patients: median age 53 (range 19-75) years; 14 females, 8 males. SBE colonoscopy succeeded in cecal intubation in 22 (96%) procedures, with a median total procedure time of 30 (range 20-60) minutes. SBE colonoscopy was normal in 9 cases but resulted in a positive diagnosis in 13 (57%) procedures, including polyps (n = 6), active Crohn's disease (n = 4), Crohn's-related stricture (n = 1), and diverticulosis (n = 2). Seven (30%) procedures were therapeutic including 1 case with balloon dilation and 6 cases with polypectomy. No complications were encountered. LIMITATIONS: Limited sample size, no direct comparison with double-balloon endoscopy. CONCLUSIONS: Single-balloon-assisted colonoscopy seems a safe and effective method for completing colonoscopy in patients with previously failed or difficult colonoscopy. The outcomes are similar compared with previous studies with DBE colonoscopy in this patient group.