Clinical Research Directory

Blood Flow and Oxygenation in the Portal Vein in Subjects With Chronic Narrowing of the Blood Vessels to the Gut

In this study the investigators will, with an Magnetic Resonance Imaging (MRI) method, measure the oxygen content in the portal vein, which conduct the blood from the guts to the liver. Examinations will be performed on 20 subjects with meal related abdominal pain due to severe narrowing of the vessels conduction blood to the guts,compared to 20 subjects with similar narrowing of the abdominal vessels, but without meal related pain. The goal of the study is to test a non-invasive, radiation free method to diagnose patients with abdominal pain due to compromized blood supply (chronic mesenteric ischemia).

Translesional PRESSURE Measurements to Assess Clinical Relevance of a Mesenteric Artery Stenosis (PRESSURE-study)

Chronic mesenteric ischemia (CMI) is an incapacitating disease with a vast impact on quality of life due to severe abdominal pain after a meal, resulting in fear of eating and subsequent weight loss. CMI is most frequently caused by an atherosclerotic mesenteric artery stenosis, which is a frequent finding in the general population (6-29%). CMI is less prevalent due to an extensive collateral circulation protecting the gut against ischemia. Hence, imaging alone cannot be relied upon, making the diagnosis of CMI challenging. Treatment decisions for atherosclerotic CMI are currently based on history, stenosis severity on imaging, and signs of mesenteric ischemia during a functional test. Yet, sufficiency of the collateral circulation cannot be assessed, resulting in substantial failure to recover from symptoms after stentplacement (27-31% in single vessel disease), unnecessary complications, and avoidable healthcare expenses. A retrospective cohort study by van Dijk et al. reports that intra-arterial pressure measurements could predict clinical success of mesenteric artery revascularization with an 86% sensitivity and 83% specificity, indicating that mesenteric artery pressure measurements could be a highly desired and promising tool for the assessment of hemodynamic and clinical relevance of a mesenteric artery stenosis. Which is sensible, since pressure gradients will only occur when both a severe mesenteric artery stenosis and an insufficient collateral circulation are present. Another advantages of pressure measurements is the ability to simulate the postprandial physiology, using nitroglycerin, enabling measurements when mesenteric blood flow is maximal. Intra-arterial pressure measurements are currently the most promising tool to guide clinical decision making in patients with suspected CMI and could result in major improvements in quality of life by improving clinical success of mesenteric artery revascularization, decreasing complication risks and decreasing healthcare costs by facilitating allocation of health care resources to those patients actually benefitting from treatment.

Intestinal Ischemia Biomarker in Patients With Chronic Mesenteric Ischemia

Plasma Alpha glutathione S transferase (Alpha GST) has been previously demonstrated to be raised in patients with chronic mesenteric ischemia (CMI) caused by atherosclerosis and in patients with median arcuate ligament syndrome (MALS). Raised plasma level of Alpha GST has been demonstrated to decrease or normalize after surgical treatment of patients with CMI and MALS as compared with healthy individuals. This study compares the plasma Alpha GST in patients with CMI and MALS with those with 1-Morbus Crohn, 2-Gallstone disease, and age-matched healthy individuals. Besides, changes in the health-related quality of life (QoL) will be investigated in the study individuals.

Promoting Early Diagnosis of Chronic Mesenteric Ischemia

CMI is an incapacitating disease and timely diagnosis remains problematic. Despite the substantial compensatory capacity of the mesenteric circulation CMI is relatively common, its incidence being comparable to other well-known diseases like Crohn's disease. Diagnostic tools are needed for two purposes since the exclusion of CMI currently requires a cumbersome complication-prone diagnostic workup and since a definitive diagnosis is mainly established per exclusionem. First, a sensitive test is desirable to rule out CMI and avoid excessive diagnostic investigations. Quantification of mesenteric arterial calcification on computed tomography (CT) seems suitable for this purpose, synonymous with the coronary artery calcium score. Second, a specific test is required confirming CMI by detection of mucosal ischemia during a meal, when oxygen demand peaks. A breath test, based on the requirement of oxygen to absorb and metabolize 13C-butyrate in the enterocyte, could detect mucosal ischemia Objective: Facilitating diagnosis of chronic mesenteric ischemia (CMI) using 1) the mesenteric artery calcium score (MACS) and 2) mucosal ischemia detection by butyrate breath testing Study design: Multicentre prospective cohort studies.

European Multicentre Study of Long-term Results Following Visceral Arteries Revascularization: the E-VisAR Study

Visceral arteries pathologies are a broad-spectrum of conditions with an extremely low incidence, estimated at 9.2% and 6.2% per 100,000 inhabitants for chronic and acute mesenteric ischemia, respectively, and 0.01-0.2% for aneurysms. The literature regarding the topic is limited in number and fragmented, having multiple vessels involved along with rare conditions caused by different aetiologies. However, these diseases are of utmost importance considering that acute presentation is common and the treatment in urgent setting is challenging and still facing high mortality rates. There are still several grey areas regarding the treatment of these pathologies. The last decades showed an increasing utilization of an endovascular approach to treat visceral vessel diseases. On one hand, the early- and mid-term superiority of endovascular revascularization vs. open surgical repair has been demonstrated considering the reduction of morbidity and mortality, and length of stay. However, publications reporting long-term (\> five years) are still lacking. This study is a real-word, ambispective, multi-arm, multicenter study that aims to evaluate the long-term results of visceral vessel revascularization in different diseases, districts, and approaches. Patients will be divided according to the target vessel and index disease. For each subgroup, a comparison between endovascular and open repair will be performed. The primary outcome is to compare endovascular and open approach in terms of survival, further divided into overall and disease-related mortality, during long term follow-up (\> 5 years). Moreover, early and mid-term data should be considered to provide reliable results. This outcome will be stratified as well within each disease- specific arm. At the study launch, data collection of patients who have undergone visceral vessels revascularization in the previous 20 years will begin. At the same time, all new cases of visceral vessel revascularization will be proposed for enrollment and follow-up in the prospective arm. The retrospective cohort will provide informative results regarding the long-term survival of these patients. This information will be used to adjust the sample size for the prospective cohort.

Investigation of Chronic Intestinal Ischemia

Patients suspected of chronic mesenteric ischemia caused by atherosclerosis or median arcuate ligament syndrome shall be investigated with trans mucosal and transserosal laser Doppler flowmeter and visible light spectroscopy.