Neither inflammatory bowel disease nor immunosuppressants are associated with an increased risk of severe COVID-19: an observational Dutch cohort study.

Conflicting data about inflammatory bowel disease [IBD] and immunosuppressants are risk factors for severe COVID-19 confuse patients and healthcare providers. Clinical reports with longer follow-up are lacking. A retrospective search was performed for severe COVID-19 (hospital admission and/or mortality) one year after the SARS-CoV-2 outbreak in an IBD cohort from one of the most affected Dutch regions. Cohort characteristics were explored by value-based healthcare data, including immunotherapy. COVID-19 cases were detected by ICD-10 codes and further examined for IBD determinants (including medication) and COVID-19 characteristics (intensive care admission, respiratory support, treatment, mortality). The national mortality register was consulted, ensuring detection of patients that died without admission. Results were compared with regional and national general population registries. The IBD cohort consisted of 1453 patients (51% Crohn's disease, 54% women, 39.9% using immunotherapy), including children. Biologics use increased during the study. Eight cases (0.55%) had severe COVID-19: seven were hospitalized (0.48%, 95% confidence interval [CI] 0.21-1.04), and two died (0.14%, CI 0.002-0.55). Six patients had comorbidity, one used immunotherapy, and four had no medication. Both deceased patients were older than 80 years, had severe comorbidity, but used no immunotherapy. Hospitalization occurred significantly more in the IBD cohort than regionally (0.18%, CI 0.17-0.19, p = 0.015), but not significantly more than nationally (0.28%, CI 0.279-0.284). Mortality was equal in IBD patients, regionally (0.11%, CI 0.10-0.12) and nationally (0.13%, CI 0.125-0.128). Neither IBD nor immunosuppressants are associated with increased risks of severe COVID-19 in an observational study with one-year follow-up.

Repeatability, and Intra-Observer and Interobserver Agreement of Two Dimensional Perfusion Angiography in Patients with Chronic Limb Threatening Ischaemia.

OBJECTIVE: Two dimensional (2D) perfusion angiography is a method that provides quantitative foot perfusion information from standard digital subtraction angiography acquisitions. The aim of this study was to test the reliability of this method in patients with chronic limb threatening ischaemia (CLTI) by investigating repeatability, and intra-observer and interobserver agreement. METHODS: Twenty patients with CLTI and a below the knee endovascular revascularisation were included in a prospective clinical study. Prior to treatment two perfusion angiography runs were acquired with a five minute interval without performing an intervention. In these recordings, regions of interest were selected and time density curves and perfusion parameters were determined. To investigate intra-observer agreement one observer performed five measurements on the same acquisition for each patient. To investigate interobserver agreement three observers performed measurements on the same acquisition for each patient. Results were presented in Bland-Altman plots and as the intraclass correlation coefficient per parameter. RESULTS: Two patients were excluded from repeatability analyses because of major motion artefacts. Repeatability analyses of the 18 remaining patients showed excellent correlation for every parameter (> .96). Intra-observer and interobserver agreement for all 20 patients were excellent for all parameters (1.00). CONCLUSION: Repeatability and intra-observer and interobserver agreement of 2D perfusion angiography in patients with CLTI were found to be excellent. It is therefore a reliable tool when used according to the standardised methods described in this study.

Novel diagnostic and imaging techniques in endovascular iliac artery procedures.

INTRODUCTION: Endovascular revascularization has become the preferred treatment for most patients with iliac artery obstructions, with a high rate of clinical and technical success. AREAS COVERED: This review will describe novel developments in the diagnosis and treatment of iliac artery obstructions including the augmentation of preprocedural imaging with advanced flow models, image fusion techniques, and state-of-the-art device-tracking capabilities. EXPERT OPINION: The combination of these developments will change the endovascular field within the next 5 years, allowing targeted iliac treatment without the need for radiographic imaging or iodinated contrast media.

Pre-operative Patient Specific Flow Predictions to Improve Haemodialysis Arteriovenous Fistula Maturation (Shunt Simulation Study): A Randomised Controlled Trial.

OBJECTIVE: An arteriovenous fistula (AVF) needs to mature before it becomes suitable to cannulate for haemodialysis treatment. Maturation importantly depends on the post-operative flow increase. Unfortunately, 20-40% of AVFs fail to mature (FTM). A patient specific computational model that predicts immediate post-operative flow was developed, and it was hypothesised that providing information from this model for planning of fistula creation might reduce FTM rates. METHODS: A multicentre, randomised controlled trial in nine Dutch hospitals was conducted in which patients with renal failure who were referred for AVF creation, were recruited. Patients were randomly assigned (1:1) to the control or computer simulation group. Both groups underwent a work up, with physical and duplex ultrasonography (DUS) examination. In the simulation group the data from the DUS examination were used for model simulations, and based on the immediate post-operative flow prediction, the ideal AVF configuration was recommended. The primary endpoint was AVF maturation defined as an AVF flow ≥500 mL/min and a vein inner diameter of ≥4 mm six weeks post-operatively. The secondary endpoint was model performance (i.e. comparisons between measured and predicted flows, and (multivariable) regression analysis for maturation probability with accompanying area under the receiver operator characteristic curve [AUC]). RESULTS: A total of 236 patients were randomly assigned (116 in the control and 120 in the simulation group), of whom 205 (100 and 105 respectively) were analysed for the primary endpoint. There was no difference in FTM rates between the groups (29% and 32% respectively). Immediate post-operative flow prediction had an OR of 1.15 (1.06-1.26; p < .001) per 100 mL/min for maturation, and the accompanying AUC was 0.67 (0.59-0.75). CONCLUSION: Providing pre-operative patient specific flow simulations during surgical planning does not result in improved maturation rates. Further study is needed to improve the predictive power of these simulations in order to render the computational model an adjunct to surgical planning.

Fluoroscopy with MRA fusion image guidance in endovascular iliac artery interventions: study protocol for a randomized controlled trial (3DMR-Iliac-roadmapping study).

BACKGROUND: Endovascular iliac artery interventions rely on the use of two-dimensional digital subtraction angiographies with an iodinated contrast agent and ionizing radiation. The amount of iodinated contrast agent should be limited because of its potentially nephrotoxic effects. Three-dimensional (3D) image fusion requires registration of a preprocedural magnetic resonance angiogram (MRA) or computed tomography (CT) angiogram to a perprocedurally acquired cone-beam CT or two fluoroscopic orthogonal projections. After registration, the 3D angiography images can be overlaid on the fluoroscopy screen and will follow table and C-arm movements. This study will assess the added value of the 3D image fusion technique in iliac artery interventions regarding the amount of the iodinated contrast agent administered. METHODS/DESIGN: The study cohort will comprise 106 patients (> 18 years) with symptomatic common and/or external iliac artery stenoses or occlusions and a recent (< 6 months) diagnostic MRA from the pelvis through the lower extremities, for which an endovascular intervention is indicated. Patients will be randomized into the control or study group (i.e. treatment without or with 3D image fusion guidance). The primary endpoint is the amount of administered iodinated contrast agent (mL). Secondary outcomes are technical success of the procedure, defined as < 30% residual stenosis over the treated lesion, fluoroscopy time, and radiation dose as dose area product (mGycm2). Patient participation in the study will be completed after hospital discharge. DISCUSSION: This study is a randomized controlled multicenter trial to provide evidence on the effect of the 3D image fusion technique on the amount of administered iodinated contrast during endovascular common and/or external iliac artery interventions. TRIAL REGISTRATION: Nederlands Trial Register, NTR5008 . Registered on 16 December 2014.

In Vivo Validation of Patient-Specific Pressure Gradient Calculations for Iliac Artery Stenosis Severity Assessment.

BACKGROUND: Currently, the decision to treat iliac artery stenoses is mainly based on visual inspection of digital subtraction angiographies. Intra-arterial pressure measurements can provide clinicians with accurate hemodynamic information. However, pressure measurements are rarely performed because of their invasiveness and the time required. Therefore, the aim of the study was to test the feasibility of a computational model that can predict translesional pressure gradients across iliac artery stenoses on the basis of imaging data only. METHODS AND RESULTS: Patients (N=21) with symptomatic peripheral arterial disease and a peak systolic velocity ratio between 2.5 and 5.0 were included in the study. Patients underwent per-procedural 3-dimensional rotational angiography and hyperemic intra-arterial translesional pressure measurements. Vascular anatomical features were reconstructed from the 3-dimensional rotational angiography data into an axisymmetrical 2-dimensional computational mesh, and flow was estimated on the basis of the stenosis geometry. Computational fluid dynamics were performed to predict the pressure gradient and were compared with the measured pressure gradients. A good agreement by overlapping error bars of the predicted and measured pressure gradients was found in 21 of 25 lesions. Stratification of the stenosis on the basis of the predicted pressure gradient into hemodynamic not significant (<10 mm Hg) and hemodynamic significant (≥10 mm Hg) resulted in sensitivity, specificity, and overall predictive values of 95%, 60%, and 88%, respectively. CONCLUSIONS: The feasibility of the patient-specific computational model to predict the hyperemic translesional pressure gradient over iliac artery stenosis was successfully tested. Presented results suggest that, with further optimization and corroboration, the model can become a valuable aid to the diagnosis of equivocal iliac artery stenosis. CLINICAL TRIAL REGISTRATION: URL: http://www.trialregister.nl. Unique identifier: NTR5085.

Pros and Cons of 3D Image Fusion in Endovascular Aortic Repair: A Systematic Review and Meta-analysis.

PURPOSE: To systematically review and meta-analyze the added value of 3-dimensional (3D) image fusion technology in endovascular aortic repair for its potential to reduce contrast media volume, radiation dose, procedure time, and fluoroscopy time. METHODS: Electronic databases were systematically searched for studies published between January 2010 and March 2016 that included a control group describing 3D fusion imaging in endovascular aortic procedures. Two independent reviewers assessed the methodological quality of the included studies and extracted data on iodinated contrast volume, radiation dose, procedure time, and fluoroscopy time. The contrast use for standard and complex endovascular aortic repairs (fenestrated, branched, and chimney) were pooled using a random-effects model; outcomes are reported as the mean difference with 95% confidence intervals (CIs). RESULTS: Seven studies, 5 retrospective and 2 prospective, involving 921 patients were selected for analysis. The methodological quality of the studies was moderate (median 17, range 15-18). The use of fusion imaging led to an estimated mean reduction in iodinated contrast of 40.1 mL (95% CI 16.4 to 63.7, p=0.002) for standard procedures and a mean 70.7 mL (95% CI 44.8 to 96.6, p<0.001) for complex repairs. Secondary outcome measures were not pooled because of potential bias in nonrandomized data, but radiation doses, procedure times, and fluoroscopy times were lower, although not always significantly, in the fusion group in 6 of the 7 studies. CONCLUSION: Compared with the control group, 3D fusion imaging is associated with a significant reduction in the volume of contrast employed for standard and complex endovascular aortic procedures, which can be particularly important in patients with renal failure. Radiation doses, procedure times, and fluoroscopy times were reduced when 3D fusion was used.