Iodine density mapping for the diagnosis of acute bowel ischemia using fast kV-switching dual-energy CT

PURPOSE

To evaluate the diagnostic capabilities of a supplementary color ramped iodine density map compared to virtual monoenergetic images (VMIs) at 74 keV in the diagnosis of acute bowel ischemia (ABI).

METHODS

Data for this study were prospectively gathered and retrospectively evaluated. Patients referred to the Department of Diagnostic Radiology between October 2020 and August 2022 on the suspicion of ABI and underwent surgery < 12 h following fast kV-switching venous phase abdominal dual-energy CT (DECT) were consecutively included. Images were evaluated by two board-certified radiologists and two radiology residents. First round included only 74 keV VMIs resembling conventional 120 kVp images, and the second round included a supplementary iodine density map. Readers were asked to register presence of ABI as well as their confidence in their diagnosis based on a 5-point Likert scale. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for each observer with the surgical findings as the gold-standard. McNemar's and Wilcoxon signed-rank test were used to compare registrations and diagnostic confidence across assessment rounds.

RESULTS

A total of 29 patients resulting in 31 DECT scans were included. Fourteen cases of ischemic/necrotic bowel were reported following surgery. Sensitivity and NPV were decreased with the use of supplementary iodine map images compared to 120 kVp-like images without supplementary iodine map images for three of four observers (round 1 range: 71.4-92.9% and 78.0-94.8%; round 2 range: 57.1-78.6% and 70.1-83.3%, respectively), while specificity and PPV were increased for three of four observers (round 1 range: 64.7-94.1% and 67.4-93.1%; round 2 range: 88.2-94.1% and 73.8-91.1%, respectively). However, no significant difference in ABI diagnosis or diagnostic confidence was found (p-value range: 0.07-1.00 and 0.23-0.58, respectively).

CONCLUSION

No significant difference for the diagnosis of ABI was found using supplementary iodine mapping. Our study may suggest a trend of increased specificity and decreased sensitivity, hence, the use of supplementary iodine mapping should be carefully considered.

Characterizing incidental mass lesions in abdominal dual-energy CT compared to conventional contrast-enhanced CT

BACKGROUND

Incidental findings are common in abdominal computed tomography (CT) and often warrant further investigations with economic implications as well as implications for patients.

PURPOSE

To evaluate the potential of dual-energy CT (DECT) in the identification and/or characterization of abdominal incidental mass lesions compared to conventional contrast-enhanced CT.

MATERIAL AND METHODS

This retrospective study from a major tertiary hospital included 96 patients, who underwent contrast-enhanced abdominal DECT. Incidental lesions in adrenals, kidneys, liver, and pancreas were evaluated by two board-certified abdominal radiologists. Observer 1 only had access to standard CT reconstructions, while observer 2 had access to standard CT as well as DECT reconstructions. Disagreements were resolved by consensus review and used as a reference for observers using McNemar's test.

RESULTS

Observers 1 and 2 identified a total of 40 and 34 findings, respectively. Furthermore, observer 1 registered 13 lesions requiring follow-up, of which seven (two renal and five adrenal lesions) were resolved following consensus review using DECT (P = 0.008). The inter-observer agreement was near perfect (κ = 0.82).

CONCLUSION

DECT has the potential to improve the immediate characterization of incidental findings when compared to conventional CT for abdominal imaging.

Learning insertion of a Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) catheter: Is clinical experience necessary? A prospective trial

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an emerging and potentially life-saving procedure, necessitating qualified operators in an increasing number of centres. The procedure shares technical elements with other vascular access procedures using the Seldinger technique, which is mastered by doctors not only in endovascular specialties but also in trauma surgery, emergency medicine, and anaesthesiology. We hypothesised that doctors mastering the Seldinger technique (experienced anaesthesiologist) would learn the technical aspects of REBOA with limited training and remain technically superior to doctors unfamiliar with the Seldinger technique (novice residents) given similar training.

METHODS

This was a prospective trial of an educational intervention. Three groups of doctors were enroled: novice residents, experienced anaesthesiologists, and endovascular experts. The novices and the anaesthesiologists completed 2.5 h of simulation-based REBOA training. Their skills were tested before and 8-12 weeks after training using a standardised simulated scenario. The endovascular experts, constituting a reference group, were equivalently tested. All performances were video recorded and rated by three blinded experts using a validated assessment tool for REBOA (REBOA-RATE). Performances were compared between groups and with a previously published pass/fail cutoff.

RESULTS

Sixteen novices, 13 board-certified specialists in anaesthesiology, and 13 endovascular experts participated. Before training, the anaesthesiologists outperformed the novices by 30 percentage points of the maximum REBOA-RATE score (56% (SD 14.0) vs 26% (SD 17%), p<0.01). After training, there was no difference in skills between the two groups (78% (SD 11%) vs 78 (SD 14%), p = 0.93). Neither group reached the endovascular experts' skill level (89% (SD 7%), p<0.05).

CONCLUSION

For doctors mastering the Seldinger technique, there was an initial inter-procedural transfer of skills advantage when performing REBOA. However, after identical simulation-based training, novices performed equally well to anaesthesiologists, indicating that vascular access experience is not a prerequisite to learning the technical aspects of REBOA. Both groups would need more training to reach technical proficiency.

Evaluation of thin-slice abdominal DECT using deep-learning image reconstruction in 74 keV virtual monoenergetic images: an image quality comparison

PURPOSE

To compare noise, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and image quality using deep-learning image reconstruction (DLIR) vs. adaptive statistical iterative reconstruction (ASIR-V) in 0.625 and 2.5 mm slice thickness gray scale 74 keV virtual monoenergetic (VM) abdominal dual-energy CT (DECT).

METHODS

This retrospective study was approved by the institutional review board and regional ethics committee. We analysed 30 portal-venous phase abdominal fast kV-switching DECT (80/140kVp) scans. Data were reconstructed to ASIR-V 60% and DLIR-High at 74 keV in 0.625 and 2.5 mm slice thickness. Quantitative HU and noise assessment were measured within liver, aorta, adipose tissue and muscle. Two board-certified radiologists evaluated image noise, sharpness, texture and overall quality based on a five-point Likert scale.

RESULTS

DLIR significantly reduced image noise and increased CNR as well as SNR compared to ASIR-V, when slice thickness was maintained (p < 0.001). Slightly higher noise of 5.5-16.2% was measured (p < 0.01) in liver, aorta and muscle tissue at 0.625 mm DLIR compared to 2.5 mm ASIR-V, while noise in adipose tissue was 4.3% lower with 0.625 mm DLIR compared to 2.5 mm ASIR-V (p = 0.08). Qualitative assessments demonstrated significantly improved image quality for DLIR particularly in 0.625 mm images.

CONCLUSIONS

DLIR significantly reduced image noise, increased CNR and SNR and improved image quality in 0.625 mm slice images, when compared to ASIR-V. DLIR may facilitate thinner image slice reconstructions for routine contrast-enhanced abdominal DECT.

Focus on Radiation Protection Improves Both Correct Behavior and Procedural Performance During Simulation-Based Training - A Randomized Comparison

BACKGROUND

To explore whether simulation-based endovascular training with focus on radiation safety could improve correct behavior without jeopardizing the learning of procedural skills.

METHODS

Twenty-four residents without previous endovascular experience completed 10 clinical scenarios on a virtual-reality endovascular simulator with software for peripheral endovascular interventions. Participants were randomized to receive feedback (n = 12) or not (n = 12) on radiation protection (RP) performance after each case. Expert assessments were done at the first, second, fourth, seventh, and 10th case on RP and endovascular skills (ES). Automatic simulator metrics on procedure time, contrast dose, handling errors, and estimated radiation exposure to patient and operator were registered. Outcome metrics were analyzed by two-way mixed analysis of variance pairwise comparisons with independent t-tests. Correlations were explored using Pearson's r for internal consistency reliability.

RESULTS

The RP performance was similar in both groups at their first attempt (P = 0.61), but the feedback group significantly outperformed the control group over time (P < 0.001 for all comparisons). The feedback group was however slower to learn the ES at start (P = 0.047 at second performance), but after 7 attempts no difference was shown (P = 0.59). The feedback group used more time (19.5 vs. 15.3 min; P = 0.007) but less contrast (60 vs. 100 mL; P < 0.001). The number of errors was the same in both groups, but all metrics regarding radiation exposure favored the feedback group (P-values from 0.001 to 0.008).

CONCLUSIONS

Simulation-based training (SBT) is effective to acquire basic endovascular intervention skills and concurrently learn RP behavior when feedback on radiation culture is provided.

Quantitative and qualitative assessments of deep learning image reconstruction in low-keV virtual monoenergetic dual-energy CT

OBJECTIVES

To evaluate a novel deep learning image reconstruction (DLIR) technique for dual-energy CT (DECT) derived virtual monoenergetic (VM) images compared to adaptive statistical iterative reconstruction (ASIR-V) in low kiloelectron volt (keV) images.

METHODS

We analyzed 30 venous phase acute abdominal DECT (80/140 kVp) scans. Data were reconstructed to ASIR-V and DLIR-High at four different keV levels (40, 50, 74, and 100) with 1- and 3-mm slice thickness. Quantitative Hounsfield unit (HU) and noise assessment were measured within the liver, aorta, fat, and muscle. Subjective assessment of image noise, sharpness, texture, and overall quality was performed by two board-certified radiologists.

RESULTS

DLIR reduced image noise by 19.9-35.5% (p < 0.001) compared to ASIR-V in all reconstructions at identical keV levels. Contrast-to-noise ratio (CNR) increased by 49.2-53.2% (p < 0.001) in DLIR 40-keV images compared to ASIR-V 50 keV, while no significant difference in noise was identified except for 1 and 3 mm in aorta and for 1-mm liver measurements, where ASIR-V 50 keV showed 5.5-6.8% (p < 0.002) lower noise levels. Qualitative assessment demonstrated significant improvement particularly in 1-mm reconstructions (p < 0.001). Lastly, DLIR 40 keV demonstrated comparable or improved image quality ratings when compared to ASIR-V 50 keV (p < 0.001 to 0.22).

CONCLUSION

DLIR significantly reduced image noise compared to ASIR-V. Qualitative assessment showed that DLIR significantly improved image quality particularly in thin sliced images. DLIR may facilitate 40 keV as a new standard for routine low-keV VM reconstruction in contrast-enhanced abdominal DECT.

KEY POINTS

• DLIR enables 40 keV as the routine low-keV VM reconstruction. • DLIR significantly reduced image noise compared to ASIR-V, across a wide range of keV levels in VM DECT images. • In low-keV VM reconstructions, improvements in image quality using DLIR were most evident and consistent in 1-mm sliced images.

Prostatic artery embolization in men with severe hemophilia a: a case report of two patients

Background

This is the first case report describing the peri- and postoperative hemostasis plans in two men with severe hemophilia A (HA) who underwent prostatic artery embolization (PAE) for symptomatic benign prostatic hyperplasia (BPH).

Case presentation

Two patients with severe HA and lower urinary tract symptoms (LUTS) not responding to medical therapy underwent PAE at our institution. In both patients, intermittent administration of decreasing doses of extended half-life recombinant factor VIII (EHL rFVIII) concentrate from 30 min before to 7 days after the PAE resulted in good hemostatic control. In addition to EHL rFVIII, tranexamic acid was administered in the same timeframe to augment the action of EHL rFVIII and to account for possible mucosal bleeding from the urinary tract. Both patients reported a minor localized hematoma at the femoral puncture site in the right groin, that resolved spontaneously. No other bleeding complications were observed.

Conclusions

The procoagulant effects of the chosen dosing of EHL rFVIII showed sufficient to perform a technically successful embolization. At 6 months follow-up, both patients had significant reduction in self-reported urinary symptoms and were content with the outcome.

Assessment of Liver Fat: Dual-Energy CT versus Conventional CT with and without Contrast

We assessed the correlation between liver fat percentage using dual-energy CT (DECT) and Hounsfield unit (HU) measurements in contrast and non-contrast CT. This study included 177 patients in two patient groups: Group A (n = 125) underwent whole body non-contrast DECT and group B (n = 52) had a multiphasic DECT including a conventional non-contrast CT. Three regions of interest were placed on each image series, one in the left liver lobe and two in the right to measure Hounsfield Units (HU) as well as liver fat percentage. Linear regression analysis was performed for each group as well as combined. Receiver operating characteristic (ROC) curve was generated to establish the optimal fat percentage threshold value in DECT for predicting a non-contrast threshold of 40 HU correlating to moderate-severe liver steatosis. We found a strong correlation between fat percentage found with DECT and HU measured in non-contrast CT in group A and B individually (R² = 0.81 and 0.86, respectively) as well as combined (R² = 0.85). No significant difference was found when comparing venous and arterial phase DECT fat percentage measurements in group B (p = 0.67). A threshold of 10% liver fat found with DECT had 95% sensitivity and 95% specificity for the prediction of a 40 HU threshold using non-contrast CT. In conclusion, liver fat quantification using DECT shows high correlation with HU measurements independent of scan phase.

Pressure Difference Estimation in Non-stenotic Carotid Bifurcation Phantoms Using Vector Flow Imaging

Local pressure differences estimated using vector flow imaging (VFI) and direct catheterization in seven carotid bifurcation phantoms were compared with simulated pressure fields. VFI correlated strongly with simulated peak pressure differences (r = 0.99, p < 0.00001), with an average overestimation of 12.3 Pa (28.6%). The range between the lowest and highest pressure difference of VFI underestimated simulations by 4.6 Pa (8.06%; r = 0.99, p < 0.0001). The catheter method exhibited no correlation (r = -0.09, p = 0.85). Ten repeated measurements on one phantom revealed a small standard deviation (SD) for VFI (SD = 8.4%, mean estimated SD = 11.5%), but not for the catheter method (SD = 785.6%). An in vivo peak systolic pressure difference of 97.9 Pa (estimated SD = 30%) was measured using VFI in one healthy individual. This study indicates that VFI pressure difference estimation is feasible in phantoms and in vivo and realistic estimates of the SD can be attained from the data.

Transthoracic Vector Flow Imaging in Pediatric Patients with Valvular Stenosis - A Proof of Concept Study

Purpose Continuous wave Doppler ultrasound is routinely used to detect cardiac valve stenoses. Vector flow imaging (VFI) is an angle-independent real-time ultrasound method that can quantify flow complexity. We aimed to evaluate if quantification of flow complexity could reliably assess valvular stenosis in pediatric patients.

Materials and Methods Nine pediatric patients with echocardiographically confirmed valvular stenosis were included in the study. VFI and Doppler measurements were compared with transvalvular peak-to-peak pressure differences derived from invasive endovascular catheterization.

Results Vector concentration correlated with the catheter measurements before intervention after exclusion of one outlier (r=−0.83, p=0.01), whereas the Doppler method did not (r=0.49, p=0.22). The change in vector concentration after intervention correlated strongly with the change in the measured catheter pressure difference (r=−0.86, p=0.003), while Doppler showed a tendency for a moderate correlation (r=0.63, p=0.07).

Conclusion Transthoracic flow complexity quantification calculated from VFI data is feasible and may be useful for assessing valvular stenosis severity in pediatric patients.

Efficacy of dexamethasone in reducing the postembolisation syndrome in men undergoing prostatic artery embolisation for benign prostatic hyperplasia: protocol for a single-centre, randomised, double-blind, placebo-controlled trial-the 'DEXAPAE' study

INTRODUCTION

Postembolisation syndrome (PES) is the most common side effect of vascular embolisation of solid organs. Although prophylactic corticosteroids are known to reduce the incidence and severity of PES, no trials investigating their efficacy have been conducted in men undergoing prostatic artery embolisation (PAE). We postulate that steroids can have a similar effect in reducing PES after PAE. This paper describes the rationale and detailed protocol for a randomised controlled trial evaluating the efficacy of dexamethasone (DEXA) in reducing PES after PAE.

METHODS AND ANALYSIS

In this single-centre, randomised, double-blind, placebo-controlled trial, we will enrol 60 individuals undergoing PAE for benign prostatic hyperplasia. Participants will be randomised to receive IV DEXA (24 mg) or placebo (saline). The primary outcomes will be postprocedural fever, pain and quality of life. The secondary outcomes will include postprocedural nausea, postprocedural medicine usage, laboratory parameters (C reactive protein, prostate-specific antigen) and early PAE results.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Danish Committee on Health Research Ethics in the Capital Region (H-20025910). The results from this trial will be disseminated through publication in peer-reviewed journals and national and international presentations.

TRIAL REGISTRATION NUMBER

Clinicaltrials.gov identifier: NCT04588857; EudraCT number: 2020-000915-53.

Reliable and valid assessment of procedural skills in resuscitative endovascular balloon occlusion of the aorta

BACKGROUND

Valid and reliable assessment of skills is essential for improved and evidence-based training concepts. In a recent study, we presented a novel tool to assess procedural skills in resuscitative endovascular balloon occlusion of the aorta (REBOA), REBOA-RATE, based on international expert consensus. Although expert consensus is a strong foundation, the performance of REBOA-RATE has not been explored. The study aimed to examine the reliability and validity of REBOA-RATE.

METHODS

This was an experimental simulation-based study. We enrolled doctors with three levels of expertise to perform two REBOA procedures in a simulated scenario of out-of-hospital cardiac arrest. Procedures were video-recorded, and videos were blinded and randomized. Three clinical experts independently rated all procedures using REBOA-RATE. Data were analyzed using Messick's framework for validity evidence, including generalizability analysis of reliability and determination of a pass/fail standard.

RESULTS

Forty-two doctors were enrolled: 16 novices, 13 anesthesiologists, and 13 endovascular experts. They all performed two procedures, yielding 84 procedures and 252 ratings. The REBOA-RATE assessment tool showed high internal consistency (Cronbach's α = 0.95) and excellent interrater reliability (intraclass correlation coefficient, 0.97). Assessment using one rater and three procedures could ensure overall reliability suitable for high-stakes testing (G-coefficient >0.80). Mean scores (SD) for the three groups in the second procedure were as follows: novices, 32% (24%); anesthesiologists, 55% (29%); endovascular experts, 93% (4%) (p < 0.001). The pass/fail standard was set at 81%, which all experts but no novices passed.

CONCLUSION

Data strongly support the reliability and validity of REBOA-RATE, which successfully discriminated between all experience levels. The REBOA-RATE assessment tool requires minimal instruction, and one rater is sufficient for reliable assessment. Together, these are strong arguments for the use of REBOA-RATE to assess REBOA skills, allowing for competency-based training and certification concepts.

LEVEL OF EVIDENCE

Diagnostic test, no or poor gold standard, level V.

Current Status of Trans-Arterial Embolization in Pain Management of Musculoskeletal Inflammatory Conditions - An Evidence-Based Review

OBJECTIVE

To summarize the literature on trans-arterial embolization in inflammatory musculoskeletal conditions, focusing on efficacy and safety.

MATERIALS AND METHODS

PRISMA guidelines were followed. A systematic literature search revealed 19 studies, with a total of 394 participants, eligible for inclusion.

RESULTS

The included studies consisted of case reports/series and non-randomized interventional studies, with knee osteoarthritis and adhesive capsulitis of the shoulder as the most frequent conditions. In all studies except one, pain was reduced up to four years after treatment. All adverse events were transient. Due to high heterogeneity, meta-analysis was not possible.

CONCLUSION

The included early studies showed encouraging results regarding efficacy and safety. However, randomized, placebo-controlled trials are warranted.

Selective arterial embolization of renal angiomyolipomas: A 10‐year experience

Objectives

To study safety and efficacy of selective endovascular trans‐arterial embolization (TAE) of renal angiomyolipoma (AML) in a 10‐year period at a regional tertiary referral center in Denmark.

Patients and methods

All 56 patients who underwent TAE of renal AML at Departments of Urology and Radiology, Copenhagen University Hospital – Rigshospitalet, Denmark, from 2009 to 2020 were included. Seven without preoperative and postoperative imaging were excluded, leaving 49 patients for analysis. From national electronic medical records, we retrieved patient characteristics, surgical data, and follow‐up data. Tumor size at the time of embolization and during follow‐up was compared using Student's paired t test. Estimated glomerular filtration rate (eGFR) pre‐ and post‐embolization were compared using Wilcoxon rank sum test.

Results

We included 49 patients of whom 4 had two tumors treated in the same TAE procedure. Median age was 50 years (interquartile range [IQR]: [29–67 years]), and the median follow‐up time was 4.6 years [IQR: 3.0–6.7 years]. Post‐embolization syndrome (PES) was experienced in 27 patients, and non‐PES in 5 patients. Median length of hospital stay was 0 days [IQR, 0–1]. Postoperative Everolimus immunosuppressive treatment was offered to seven patients. Median tumor size was 6.0 cm [IQR: 4.6–7.9 cm] and was significantly reduced to 3.7 cm [IQR: 2.5–5.2 cm] after treatment (p < 0.001). Kidney function was not affected by TAE. Three deaths, not related to AML, were noted during follow‐up.

Conclusion

Embolization of AML was in this cohort effective to significantly reduce tumor size without serious adverse events and loss of renal function. TAE is a safe and efficacious treatment and the preferred minimally invasive treatment option of AML.

Developing a tool to assess competence in resuscitative endovascular balloon occlusion of the aorta: An international Delphi consensus study

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an emergency procedure that is potentially lifesaving in major noncompressible torso hemorrhage. It may also improve outcome in nontraumatic cardiac arrest. However, the procedure can be technically challenging and requires the immediate presence of a qualified operator. Thus, evidence-based training and assessment of operator skills are essential for successful implementation and patient safety. A prerequisite for this is a valid and reliable assessment tool specific for the procedure. The aim of this study was to develop a tool for assessing procedural competence in REBOA based on best-available knowledge from international experts in the field.

METHODS

We invited international REBOA experts from multiple specialties to participate in an anonymous three-round iterative Delphi study to reach consensus on the design and content of an assessment tool. In round 1, participants suggested items to be included. In rounds 2 and 3, the relevance of each suggested item was evaluated by all participants to reach consensus. Interround data processing was done systematically by a steering group.

RESULTS

Forty panelists representing both clinical and educational expertise in REBOA from 16 countries (in Europe, Asia, and North and South America) and seven different specialties participated in the study. After 3 Delphi rounds and 532 initial item suggestions, the panelists reached consensus on a 10-item assessment tool with behaviorally anchored rating scales. It includes assessment of teamwork, procedure time, selection and preparation of equipment, puncture technique, guidewire handling, sheath handling, placement of REBOA catheter, occlusion, and evaluation.

CONCLUSION

We present the REBOA-RATE assessment tool developed systematically by international experts in the field to optimize content validity. Following further studies of its validity and reliability, this tool represents an important next step in evidence-based training programs in REBOA, for example, using mastery learning.

LEVEL OF EVIDENCE

Therapeutic, level V.

[Dual-energy CT]

Dual-energy CT (DECT) is an emerging imaging technique and has become increasingly available in Danish hospitals in recent years. DECT utilizes data acquired from high and low kV photons. This allows for the separation of materials based on their atomic buildup, which can be visualised and quantified during post-processing. DECT entails a broad range of clinical applications across multiple organ systems and can support diagnostic decision-making as described in this review. DECT is not yet widely utilised mainly due to limited knowledge combined with a new workflow for the radiologist.

Endovascular Treatment of Chronic and Acute on Chronic Mesenteric Ischaemia: Results From a National Cohort of 245 Cases

OBJECTIVE

Endovascular treatment of chronic mesenteric ischaemia (CMI) is linked to low early morbidity and mortality but a higher risk of recurrence than open repair. Mid and long term outcomes after endovascular treatment remain to be proven in larger series. The aim of this study was to assess short and mid term outcome after first line endovascular revascularisation of CMI and acute on chronic mesenteric ischaemia (AoCMI).

METHODS

This was a prospective population and registry based cohort study supplemented by a retrospective review of medical records and imaging files. A national cohort was created based on data extracted from the Danish National Registry for Vascular Surgery (Karbase) for all patients treated endovascularly for CMI or AoCMI between 2011 and 2015 in Denmark. Survival data, bowel resection, complications, re-intervention rate, and improvement of clinical symptoms were analysed, as were potential risk factors.

RESULTS

In total, 245 patients had an endovascular intervention for CMI (n = 178; 72.6%) and AoCMI (n = 67; 27.3%). One and three year survival estimates were 85% (95% confidence interval [CI] 79 - 90) and 74% (95% CI 67 - 80) in the CMI-group, and 67% (95% CI 54 - 77) and 54% (95% CI 41 - 65) in the AoCMI group. The hazard ratio for death was 1.89 (95% CI 1.23 - 2.9) for AoCMI, relative to patients with CMI. Superior mesenteric artery (SMA) stenosis, rather then occlusion, significantly increased the success of SMA recanalisation: OR 19.4 (95% CI 6.2 - 61.4) and 9.3 (95% CI 1.6 - 53.6) in the CMI and AoCMI groups, respectively. The proportion of patients reporting clinical improvement was 71% (n = 127) in the CMI group and 59% (n = 39) in the AoCMI group. Five patients (3%) in the CMI and 30 (45%) in the AoCMI groups underwent bowel resection (p < .001), and the overall length of hospital stay (LoS) was a median of two days (interquartile range [IQR] 1 - 3 days) in the CMI group and seven days (IQR 3 - 23 days) in the AoCMI group. Within the first year, re-intervention was performed in 14 patients (5.7%).

CONCLUSION

First line endovascular treatment of CMI carries a three year mortality rate of 25%, and low risk of re-occurrence of symptomatic ischaemia. Relative to CMI, patients suffering AoCMI have significantly higher morbidity and mortality, more bowel resections, and longer LoS.

Super-Resolution Imaging with Ultrasound for Visualization of the Renal Microvasculature in Rats Before and After Renal Ischemia: A Pilot Study

In vivo monitoring of the microvasculature is relevant since diseases such as diabetes, ischemia, or cancer cause microvascular impairment. Super-resolution ultrasound imaging allows in vivo examination of the microvasculature by detecting and tracking sparsely distributed intravascular microbubbles over a minute-long period. The ability to create detailed images of the renal vasculature of Sprague-Dawley rats using a modified clinical ultrasound platform was investigated in this study. Additionally, we hypothesized that early ischemic damage to the renal microcirculation could be visualized. After a baseline scan of the exposed kidney, 10 rats underwent clamping of the renal vein (n = 5) or artery (n = 5) for 45 min. The kidneys were rescanned at the onset of clamp release and after 60 min of reperfusion. Using a processing pipeline for tissue motion compensation and microbubble tracking, super-resolution images with a very high level of detail were constructed. Image filtration allowed further characterization of the vasculature by isolating specific vessels such as the ascending vasa recta with a 15–20 μm diameter. Using the super-resolution images alone, it was only possible for six assessors to consistently distinguish the healthy renal microvasculature from the microvasculature at the onset of vein clamp release. Future studies will aim at attaining quantitative estimations of alterations in the renal microvascular blood flow using super-resolution ultrasound imaging.

Flow Complexity Estimation in Dysfunctional Arteriovenous Dialysis Fistulas using Vector Flow Imaging

Non-invasive assessment is preferred for monitoring arteriovenous dialysis fistulas (AVFs). Vector concentration assesses flow complexity, which may correlate with stenosis severity. We determined whether vector concentration could assess stenosis severity in dysfunctional AVFs. Vector concentration was estimated in four stenotic phantoms at different pulse repetition frequencies. Spectral Doppler peak velocity and vector concentration were measured in 12 patients with dysfunctional AVFs. Additionally, 5 patients underwent digital subtraction angiography (DSA). In phantoms, vector concentration exhibited an inverse relationship with stenosis severity and was less affected by aliasing in severe stenoses. In nine stenoses of 5 patients undergoing DSA, vector concentration correlated strongly with stenosis severity (first stenosis: r = -0.73, p = 0.04; other stenoses; r = -0.69, p = 0.02) and mid-stenotic diameter (first stenosis: r = 0.87, p = 0.006; other stenoses: r = 0.70, p = 0.02) as opposed to peak velocities (p > 0.05). Vector concentration is less affected by aliasing in severe stenoses and correlates with DSA in patients with dysfunctional AVF.

Postembolization Syndrome after Prostatic Artery Embolization: A Systematic Review

Postembolization syndrome (PES) is the most common side effect of vascular embolization of solid organs. The aim of this review was to determine the incidence of PES and its individual components after prostatic artery embolization (PAE). A systematic review with a pre-specified search strategy for PubMed, Embase, Web of Science and Cochrane Library was performed according to PRISMA guidelines. Studies in English regarding PAE in humans with 10 or more participants were eligible for inclusion. No restrictions on participant demographics or PAE technique were imposed. The search returned 378 references, of which 32 studies with a total of 2116 patients met the inclusion criteria. The results for overall PES frequency and individual PES components were presented as median (interquartile range, (IQR)). Overall median PES frequency was 25.5% (12.5–45.8). The two most frequent individual PES components were dysuria/urethral burning and local pain, with a median frequency of 21.7% (13.8–33.3) and 20% (5.4–29.4), respectively. Most outcome measures were characterized by a marked lack of uniformity and inconsistency in reporting across studies. Development of a uniform reporting system would help the clinicians recognize and treat PES accordingly.

Simulation-Based Virtual-Reality Patient-Specific Rehearsal Prior to Endovascular Procedures: A Systematic Review

Patient-specific rehearsal (PsR) is a new concept whereby a procedure can be rehearsed virtually using the exact patient’s anatomical data prior to performing the real procedure. The aim of this study was to ascertain if endovascular virtual-reality PsR simulation enhanced performance in real life. This was done by performing a systematic review following the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines. A literature search was conducted in PubMed, Embase, The Cochrane Library and Web of Science concerning PsR in endovascular procedures. All publications were handled using Covidence. Reference lists were also screened. Data extracted from the studies were realism rating, procedure time, fluoroscopy time, contrast volume, number of angiograms and reduction of errors. Kirkpatrick’s four-level model for measuring the efficiency of training was used for guidance of the relevance of studies. The search yielded 1155 results after the exclusion of duplicates, and 11 studies were included. Four studies had a control group, including one randomized trial; the remaining seven were feasibility studies. The realism was rated high, and overall, the studies showed improvements in procedure time, fluoroscopy time and contrast volume after PsR. One study assessed and confirmed the reduction in errors after PsR. Only two studies included more than 15 patients in their cohort. Kirkpatrick’s model was applied to all studies, with one study reaching level 4. All studies found the concept of PsR to be feasible and realistic. The studies with a control group showed a reduction of overall procedure time, radiation exposure and potential errors in endovascular procedures following PsR.

P1241CALCIFICATIONS IN DIFFERENT VASCULAR BEDS ACROSS THE SPECTRUM OF CHRONIC KIDNEY DISEASE INCLUDING CALCIFIC UREMIC ARTERIOLOPATHY: ARE SKIN PUNCH BIOPSIES USEFUL?

Background and Aims

Accelerated vascular calcification in different vascular beds is common in patients with chronic kidney disease (CKD). A severe form of vascular calcifications is calcific uremic arteriolopathy (CUA) presenting with painful ischemic skin lesions and high mortality. The prognostic value of skin biopsies in relation to CUA is unclear and the prevalence of skin vascular calcifications in different stages of CKD is sparsely described.

The aim of the study was to describe the occurence of small vesssel vascular calcifications in unaffected skin biopsies in relation to calcifications in other vascular beds across the spectrum of CKD including CUA.

Method

A cross-sectional cohort (total, n=39) comprising dialysis patients with current or previous CUA (CKD5D+CUA, n=9), dialysis patients without CUA (CKD5D-CUA, n=12), patients with CKD stage 3-4 (CKD3-4, n=12), and healthy kidney controls (control, n=6). The presence of vascular calcifications in the dermis and subcutis were assessed in 4 mm punch biopsies of unaffected skin from the lateral thigh. The presence of vascular calcification was evaluated by H&E, von Kossa and Alizarin staining. The presence of breast arterial calcifications (BAC) was evaluated by mammography, the abdominal aortic calcification score (AAC) by lateral lumbar X-ray and calcification propensity was measured by T50 reflecting the calcification propensity in blood.

Results

None of the included patients showed vascular calcifications in skin biopsies.

Declining kidney function was associated with presence of BAC, increased AAC and reduced T50 (Table).

No significant difference was found between CKD5D+CUA and CKD5D-CUA regarding BAC (p=1.000), AAC (p=0.815) or T50 (p=0.165). CKD5D+CUA compared to all other groups had no difference in BAC (p=0.109) and AAC (p=0.141) but reduced T50 (p=0.004). Dialysis patients (CKD5D±CUA) had significant more BAC (p=0.003), higher AAC (p&lt;0.001) and lower T50 (p&lt;0.001).

Conclusion

No vascular calcifications were found in punch biopsies from unaffected skin in patients with different stages of CKD including CUA. Despite imaging verified vessel calcification by BAC and AAC and increased calcification propensity by T50. This suggest that conventional punch biopsies cannot be used to identify skin vascular calcification and thereby patients at risk for developing CUA.

Can Computed Tomography Perfusion Predict Treatment Response After Prostate Artery Embolization: A Feasibility Study

Prostate artery embolization (PAE) is an emerging therapy for benign prostatic hyperplasia (BPH). Optimal patient selection is an important step when introducing new treatments and several characteristics associated with a good clinical outcome has previously been proposed. However, no prognostic tool is yet available for PAE. Computed tomography perfusion is an imaging technique that provides hemodynamic parameters making it possible to estimate the prostatic blood flow (PBF). This study investigated the relationship between PBF and the response to PAE. A post hoc analysis including prostate-specific antigen (PSA) measurements before and 24-h after embolization from two prospective studies on sixteen patients undergoing PAE with BPH or prostate cancer were performed. The primary outcome was the correlation between baseline PBF and the change in PSA as a surrogate measure of treatment response. Prostate volume strongly correlated with treatment response and the response was greater with incremental amounts of injected embolic material. PBF was not associated with elevation in PSA and added no information that could guide patient selection.

European guidelines on chronic mesenteric ischaemia - joint United European Gastroenterology, European Association for Gastroenterology, Endoscopy and Nutrition, European Society of Gastrointestinal and Abdominal Radiology, Netherlands Association of Hepatogastroenterologists, Hellenic Society of Gastroenterology, Cardiovascular and Interventional Radiological Society of Europe, and Dutch Mesenteric Ischemia Study group clinical guidelines on the diagnosis and treatment of patients with chronic mesenteric ischaemia

Chronic mesenteric ischaemia is a severe and incapacitating disease, causing complaints of post-prandial pain, fear of eating and weight loss. Even though chronic mesenteric ischaemia may progress to acute mesenteric ischaemia, chronic mesenteric ischaemia remains an underappreciated and undertreated disease entity. Probable explanations are the lack of knowledge and awareness among physicians and the lack of a gold standard diagnostic test. The underappreciation of this disease results in diagnostic delays, underdiagnosis and undertreating of patients with chronic mesenteric ischaemia, potentially resulting in fatal acute mesenteric ischaemia. This guideline provides a comprehensive overview and repository of the current evidence and multidisciplinary expert agreement on pertinent issues regarding diagnosis and treatment, and provides guidance in the multidisciplinary field of chronic mesenteric ischaemia.

In Situ Vein Bypass Is Superior to Endovascular Treatment of Femoropopliteal Lesions in Chronic Limb-Threatening Ischemia

BACKGROUND

The objective of the study was to compare bypass surgery and endovascular revascularization of the femoropopliteal segment in patients with peripheral arterial disease and critical limb-threatening ischemia (CLTI).

METHODS

This is a single-center study including patients undergoing first-time lower extremity intervention with peripheral bypass surgery or percutaneous transluminal angioplasty with or without stenting (PTA/S) of the femoropopliteal segment because of CLTI from 2011 to 2015. Based on prospective entered data from the Danish Vascular Registry, the primary end points were amputation-free survival, overall mortality, and reinterventions.

RESULTS

A total of 679 patients with CLTI were included of which 35% (n = 239) were treated with PTA/S, 54% (n = 363) with vein bypass, and 11% (n = 77) with synthetic bypass. After 3 years, amputation-free survival was significantly better with a vein bypass (41.8% [95% CI: 35-48.4]) than both PTA/S (29.7% (95% CI: 22.7-37)) and synthetic bypass (31.7% [95% CI: 19-45.1]). Overall, the endovascular-treated patients faced more than 50% increased risk of major amputation or death than that of a vein bypass, after adjusting for comorbidity and Trans-Atlantic Inter-Society Consensus (TASC) classification (HR: 1.56 [95% CI: 1.21-2.05]). As expected, postoperative complications, length of hospital stay, and reinterventions were more frequent in the bypass groups.

CONCLUSIONS

In this nonrandomized study, autologous vein bypass was superior to both PTA/S and synthetic bypass in regard to amputation-free survival and overall mortality. Despite the increased frequency of surgical complications, a vein bypass appears justified in both shorter (TASC B-C) and longer (TASC D) femoropopliteal lesions.

Training and assessment of competence in resuscitative endovascular balloon occlusion of the aorta (REBOA) - a systematic review

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a potentially life-saving but high-risk emergency procedure in patients with haemorrhagic shock. Lack of physicians with competence in the procedure is a barrier to implementation of REBOA. It is currently unclear how training and assessment of competence should be done.

OBJECTIVES

To report and evaluate research in training and assessment of competence in REBOA and femoral arterial access with the aim to investigate the effect of simulation-based training in the procedure and to provide suggestions for the future design of training programs and assessment tools.

METHODS

Following PRISMA guidelines, PubMed, Embase, and Cochrane Library databases were searched for studies on training or assessment of competence in REBOA and femoral arterial access. Bias assessment was done using the Medical Education Research Study Quality Instrument. Evidence level was assessed using GRADE.

RESULTS

Sixteen studies were included, six of them published as abstracts. Full-text studies included 189 trainees ranging in experience level from military medics to surgical specialists. Outcome measures were heterogenous; the most used were rater checklists, knowledge testing, and procedure time. All studies confirmed an effect of training of REBOA on procedural competence in a simulation setting but had a high degree of bias. No study developed or used an assessment tool supported by validity evidence and no study investigated mid and long-term outcomes.

CONCLUSION

Simulation-based training of REBOA improves skills, however, the evidence level is very low and data cannot answer important questions on effect size, skill transfer and retention, and optimal course design. To advance research and training programmes, an assessment tool supported by validity evidence with broad applicability is needed.

Endovascular aortic repair reduces gluteal oxygenation

Background

Provoked gluteal claudication is a known risk after endovascular aortic repair (EVAR). Lowered gluteal muscle oxygenation (S_gmO₂) may be demonstrated by near-infrared spectroscopy (NIRS).

Purpose

To evaluate NIRS-determined S_gmO₂ in EVAR patients.

Material and Methods

NIRS-determined S_gmO₂ was used in an observational study design (n = 17). From the ambulatory setting, seven EVAR patients were included with reported gluteal claudication from medical records. In 10 patients scheduled for EVAR, S_gmO₂ was measured before and after the procedure. NIRS sensors were applied bilaterally on the gluteal region. Treadmill walking (12% incline, 2.4 km/h) was introduced to stress gluteal muscles.

Results

A reduced S_gmO₂ with regional side difference (P < 0.05) was noted in all 10 patients following EVAR and four reported gluteal claudication. In patients with gluteal claudication (n = 7), treadmill decreased S_gmO₂. The time to recover the S_gmO₂ was prolonged for tissue exposed to occluded hypogastric artery (median = 512 s, range = 73–1207 s vs. median = 137, range = 0–643 s; P = 0.046).

Conclusions

EVAR affects gluteal muscle oxygenation. NIRS could be used to assess whether gluteal claudication is related to lowered S_gmO₂.

Vector Flow Imaging Compared with Digital Subtraction Angiography for Stenosis Assessment in the Superficial Femoral Artery - A Study of Vector Concentration, Velocity Ratio and Stenosis Degree Percentage

Purpose

Stenosis of the superficial femoral artery (SFA) induces complex blood flow with increased velocities. Disease assessment is performed with Doppler ultrasound and digital subtraction angiography (DSA), but Doppler ultrasound is limited by angle dependency and DSA by ionizing radiation. An alternative is the vector flow imaging method based on transverse oscillation (TO), an angle-independent vector velocity technique using ultrasound. In this study, flow complexity and velocity measured with TO were compared with DSA for the assessment of stenosis in the SFA.

Materials and Methods

The vector concentration, a measure of flow complexity, and the velocity ratio obtained from the stenosis and a disease-free adjacent vessel segment, were estimated with TO in 11 patients with a total of 16 stenoses of the SFA. TO data were compared with the corresponding stenosis degree percentage obtained with DSA.

Results

The correlation between the vector concentration and DSA was very strong (R=0.93; p<0.001; 95% confidence interval (CI): 0.81-0.98), while only moderate for velocity ratio and DSA (R=0.50; p<0.07; 95% CI: 0.00-0.80). The correlation coefficients that were found were significantly different (p<0.005) without overlapping CI.

Conclusion

The study indicated that flow changes in the SFA induced by stenosis can be quantified with TO, and that stenosis grading may be improved by estimation of flow complexity instead of velocity ratio. TO is a potential diagnostic tool for the assessment of atherosclerosis and peripheral arterial disease.

Non-Invasive Assessment of Intravascular Pressure Gradients: A Review of Current and Proposed Novel Methods

Invasive catheterization is associated with a low risk of serious complications. However, although it is the gold standard for measuring pressure gradients, it induces changes to blood flow and requires significant resources. Therefore, non-invasive alternatives are urgently needed. Pressure gradients are routinely estimated non-invasively in clinical settings using ultrasound and calculated with the simplified Bernoulli equation, a method with several limitations. A PubMed literature search on validation of non-invasive techniques was conducted, and studies were included if non-invasively estimated pressure gradients were compared with invasively measured pressure gradients in vivo. Pressure gradients were mainly estimated from velocities obtained with Doppler ultrasound or magnetic resonance imaging. Most studies used the simplified Bernoulli equation, but more recent studies have employed the expanded Bernoulli and Navier⁻Stokes equations. Overall, the studies reported good correlation between non-invasive estimation of pressure gradients and catheterization. Despite having strong correlations, several studies reported the non-invasive techniques to either overestimate or underestimate the invasive measurements, thus questioning the accuracy of the non-invasive methods. In conclusion, more advanced imaging techniques may be needed to overcome the shortcomings of current methods.

Long-term follow-up after stent graft placement for access-site and access-related vascular injury during TAVI - The Bonn-Copenhagen experience

AIMS

Stent graft placement is a safe and effective treatment option for vascular complications in the context of transcatheter aortic valve implantation (TAVI). This study aimed to provide long-term angiological follow-up of stent grafts used for this indication.

METHODS AND RESULTS

Seventy-one patients (64.8% female, log EuroScore 14.7 ± 6.8%) who had undergone TAVI between March 2010 and October 2015 with implantation of a Viabahn or Fluency stent graft to treat access-site or access-related vascular injury (ASARVI) were analyzed. Implantations were mostly due to access-site bleeding complications (83.1%) in the common femoral artery (97.1%). Follow-up was performed with duplex sonography in all patients after a median of 3.9 years after TAVI (interquartile range [IQR]: 895-1749 days). Ultrasound revealed tri- or biphasic flow patterns in 16.9% and 77.6%, respectively. Stent graft patency was 100% without signs of stent graft stenosis (mean peak velocity ratio 1.0 ± 0.2). Pseudo-aneurysms or endoleaks were diagnosed in 5.6% of patients. Additional fluoroscopic and/or computed tomography (CT)-imaging was available in 36.6% of patients and did not reveal any stent fracture.

CONCLUSION

Self-expanding stent grafts provide excellent long-term function with few complications when implanted in the context of TAVI-related ASARVI.

Atherosclerotic Lesions in the Superficial Femoral Artery (SFA) Characterized with Velocity Ratios using Vector Velocity Ultrasound

Purpose

Atherosclerotic arteries are challenging to evaluate quantitatively using spectral Doppler ultrasound because of the turbulent flow conditions that occur in relation to the atherosclerotic stenoses. Vector velocity ultrasound is angle independent and provides flow information, which could potentially improve the diagnosis of arterial stenoses. The purpose of the study is to distinguish significant stenoses in the superficial femoral artery (> 50% diameter reduction) from non-significant stenoses based on velocity ratios derived from the commercially available vector velocity ultrasound technique Vector Flow Imaging (VFI).

Materials and Methods

Velocity ratios (intrastenotic blood flow velocity divided by pre- or poststenotic velocity) from a total of 16 atherosclerotic stenoses and plaques in the superficial femoral artery of 11 patients were obtained using VFI. The stenosis degree, expressed as percentage diameter reduction of the artery, was determined from digital subtraction angiography and compared to the velocity ratios.

Results

A velocity ratio of 2.5 was found to distinguish clinically relevant stenoses with>50% diameter reduction from clinically non-relevant stenoses with<50% diameter reduction and the difference was statistically significant.

Conclusion

The study indicates that VFI is a potential future tool for the evaluation of arterial stenoses.

Evaluation of Peak Reflux Velocities with Vector Flow Imaging and Spectral Doppler Ultrasound in Varicose Veins

Purpose Spectral Doppler ultrasound (SDUS) is used for quantifying reflux in lower extremity varicose veins. The technique is angle-dependent opposed to the new angle-independent Vector Flow Imaging (VFI) method. The aim of this study was to compare peak reflux velocities obtained with VFI and SDUS in patients with chronic venous disease, i. e., pathological retrograde blood flow caused by incompetent venous valves. Materials and Methods 64 patients with chronic venous disease were scanned with VFI and SDUS in the great or the small saphenous vein, and reflux velocities were compared to three assessment tools for chronic venous disease. A flow rig was used to assess the accuracy and precision of the two methods. Results The mean peak reflux velocities differed significantly (VFI: 47.4 cm/s vs. SDUS: 62.0 cm/s, p<0.001). No difference in absolute precision (p=0.18) nor relative precision (p=0.79) was found. No correlation to disease severity, according to assessment tools, was found for peak reflux velocities obtained with either method. In vitro, VFI was more accurate but equally precise when compared to SDUS. Conclusion Both VFI and SDUS detected the pathologic retrograde flow in varicose veins but measured different reflux velocities with equal precision. VFI may play a role in evaluating venous disease in the future.

Respiratory variability of peak velocities in the common femoral vein estimated with vector flow imaging and Doppler ultrasound

Respiratory variability of peak velocities (RVPV) in the common femoral vein measured with ultrasound can reveal venous outflow obstruction. Pulse wave (PW) Doppler is the gold standard for venous velocity estimation of the lower extremities. PW Doppler measurements are angle dependent, whereas vector flow imaging (VFI) can yield angle-independent measures. The hypothesis of the present study was that VFI can provide RVPV estimations without the angle dependency of PW Doppler for an improved venous disease assessment. Sixty-seven patients with symptomatic chronic venous disease were included in the study. On average, VFI measured a lower RVPV than PW Doppler (VFI: 14.11 cm/s; PW: 17.32 cm/s, p = 0.002) with a non-significant improved precision compared with PW Doppler (VFI: 21.09%; PW: 26.49%, p = 0.08). In a flow phantom, VFI had improved accuracy (p < 0.01) and equal precision compared with PW Doppler. The study indicated that VFI can characterize the hemodynamic fluctuations in the common femoral vein.

Contrast Enhanced Three Dimensional Ultrasound for Intraluminal Thrombus Assessment in Abdominal Aortic Aneurysms

OBJECTIVES

The impact of intraluminal thrombus (ILT) on abdominal aortic aneurysm (AAA) progression can be investigated non-invasively by three dimensional contrast enhanced ultrasound (3D-CEUS). The aim was to validate 3D-CEUS ILT volume and thickness measurements against computed tomography angiography (CTA), and to determine inter- and intra-operator reproducibility.

METHODS

The design was for a planned comparison of 3D-CEUS and CTA and of repeated 3D-CEUS measurements in a blinded set up. Consecutive patients with asymptomatic AAA (n = 137, maximum diameter 30-55 mm) from a single centre were consecutively assessed by CTA and 3D-CEUS in a blinded setup. After exclusion of failed CTA (n = 2) and inconclusive 3D-CEUS (n = 8), 127 3D-CEUS/CTA pairs were analysed by Bland-Altman plots. 3D-CEUS inter- and intra-operator reproducibility were determined in a subgroup (n = 30) measured twice by two blinded investigators.

RESULTS

In 24 of 127 (19%) patients, no ILT was found on 3D-CEUS. Intraluminal thrombus absence was confirmed by 3D-CTA analysis in all but two cases. Mean ILT volume difference between 3D-CEUS and CTA was 2.2 mL (5% of mean volume) and range of variability (ROV) amounted to ± 10.2 mL. Mean ILT thickness difference was 0.6 mm with a ROV of ± 4.6 mm 3D-CEUS inter-operator variations of ILT volume and thickness measurements were low (ROV ± 8.8 mL and ±2.9 mm, respectively). The corresponding intra-operator ROVs were ±7.5 mL and ±3.3 mm, respectively.

CONCLUSIONS

3D-CEUS demonstrated good reproducibility and a good agreement with CTA when estimating ILT volume and maximum thickness in AAA patients. It is a promising research tool to investigate potential interactions between ILT, AAA growth, and rupture.

Vector Flow Imaging Compared with Pulse Wave Doppler for Estimation of Peak Velocity in the Portal Vein

The study described here investigated whether angle-independent vector flow imaging (VFI) technique estimates peak velocities in the portal vein comparably to pulsed wave Doppler (PWD). Furthermore, intra- and inter-observer agreement was assessed in a substudy. VFI and PWD peak velocities were estimated with from intercostal and subcostal views for 32 healthy volunteers, and precision analyses were conducted. Blinded to estimates, three physicians rescanned 10 volunteers for intra- and inter-observer agreement analyses. The precision of VFI and PWD was 18% and 28% from an intercostal view and 23% and 77% from a subcostal view, respectively. Bias between VFI and PWD was 0.57 cm/s (p = 0.38) with an intercostal view and 9.89 cm/s (p <0.001) with a subcostal view. Intra- and inter-observer agreement was highest for VFI (inter-observer intra-class correlation coefficient: VFI 0.80, PWD 0.3; intra-observer intra-class correlation coefficient: VFI 0.90, PWD 0.69). Regardless of scan view, VFI was more precise than PWD.

Cephalic Arch Stenosis in Autogenous Brachiocephalic Hemodialysis Fistulas: Results of Cutting Balloon Angioplasty

Purpose

Cephalic arch stenosis is a known cause of hemodialysis access failure in patients with brachiocephalic fistulas (BCFs). Outcomes of endovascular treatment are affected by resistance of the stenosis to balloon dilation, a high vein rupture rate and the development of early restenosis. The purpose of this retrospective study was to report outcomes after cutting balloon angioplasty (CBA) of cephalic arch stenosis.

Methods

In our vascular access database we identified 74 dysfunctional BcFs of which 30 (41%) were caused by cephalic arch stenosis. Seventeen fistulas in 17 patients (13 males and four females; median age 62 yrs; range 52–86) were treated with CBA (June 2005 to January 2008). Twenty-five procedures were performed. In 15 procedures, a cutting balloon was used alone and in 10 procedures CBA was followed by standard or high-pressure balloon angioplasty. Restenosis rates were calculated and patency rates were estimated with the Kaplan-Meier method.

Results

Primary patency rates (±SEE) at 3, 6, 12 and 15 months were 94% (±6%), 81% (±10%), 38% (±14%) and 22% (±15%), respectively. Assisted primary patency rates (±SEE) at the same intervals were 100% (±0%), 94% (±6%), 77% (±12%) and 63% (±13%), respectively. The mean interval between radiological interventions was 13 months (SD=8) and the mean number of interventions required per patient-year of dialysis was 0.9.

Conclusion

Treatment of cephalic arch stenosis with CBA did not improve patency compared to published results of conventional PTA, but our results indicate that CBA may lower the frequency of required re-interventions.

Is EVAR a durable solution? Indications for reinterventions

INTRODUCION

Indications for reinterventions after endovascular aneurysm repair (EVAR), as well as their occurrence in number and time, are important to establish in order to optimize patient selection, postprocedure surveillance and also to guide improvements in endograft designs. The aim of this report was to present an overview of current data on reinterventions after elective EVAR.

EVIDENCE ACQUISITION

Qualitative review of studies reporting on reinterventions after elective EVAR, identified by a systematic literature search in MEDLINE, EMBASE and the Cochrane Library for publications from 2010 to 13th of November 2017.

EVIDENCE SYNTHESIS

Twenty-three studies reporting on 83,307 patients met the inclusion criteria. Index procedures were performed between 1996-2014. There was wide heterogeneity in reporting standards. Type I endoleaks were reported in 0.6%-13% and type III endoleaks in 0.9-2.1% with a significant improvement for newer devices. Migration rates varied between 0-4%. Endoleak type II was the most common indication for re-intervention ranging from 14-25.3% although the majority resolved without intervention. Rupture rates ranged from 0-5.4% and carried a high mortality (60-67%). Ruptures occurred at any time after the index procedure. Limb ischemia rates were reported at 0.4-11.9% with re-intervention rates between 0.06-11.9%. Wound related complications and related re-interventions were the indication in 0.5-14% and 0.3-6.5%, respectively. Endograft infection carried a high risk of mortality and was described in 0.3-3.6%, often related to graft-enteric fistula and the majority had an open explantation of the endograft.

CONCLUSIONS

This review showed that the rates of complications and techniques for reintervention developed over time with a tendency towards better outcomes considering the aneurysm related indications. Significant factors that led to subsequent secondary interventions were migration, rupture, infections and type I and II endoleaks. Patients treated with earlier generation endografts are still alive and need continued surveillance to detect these severe complications before they lead to rupture.

Vector and Doppler Ultrasound Velocities Evaluated in a Flow Phantom and the Femoropopliteal Vein

Ultrasound is used for evaluating the veins of the lower extremities. Operator and angle dependency limit spectral Doppler ultrasound (SDUS). The aim of the study was to compare peak velocity measurements in a flow phantom and the femoropopliteal vein of 20 volunteers with the angle-independent vector velocity technique vector flow imaging (VFI) and SDUS. In the flow phantom, VFI underestimated velocity (p = 0.01), with a lower accuracy of 5.5% (p = 0.01) and with no difference in precision, that is, error factor, compared with SDUS (VFI: 1.02 vs. SDUS: 1.02, p = 0.58). In vivo, VFI estimated lower velocities (femoral: p = 0.001; popliteal: p = 0.001) with no difference in precision compared with SDUS (femoral: VFI 1.09 vs. SDUS 1.14, p = 0.37; popliteal: VFI 1.13 vs. SDUS 1.06, p = 0.09). In conclusion, the precise VFI technique can be used to characterize venous hemodynamics of the lower extremities despite its underestimation of velocities.

[Interventional radiology in minimally invasive treatments]

Interventional radiology (IR) is a fast expanding field which includes vascular (arterial and venous) as well as non-vascular topics. IR is minimally invasive methods, which are performed under guidance of radiological modalities. The methods are in general patient-friendly and organ-sparing procedures and can often be performed on out-patient basis or with short admission to the hospital and with short reconvalescence and economic advantages compared with corresponding surgical treatments. IR has in some cases substituted former surgical procedures. Technological development has facilitated increasing IR treatment offers and indications, and there is a high level of evidence for many of the offers.

Red blood cell storage duration and long-term mortality in patients undergoing cardiac intervention: a Danish register study

OBJECTIVES

To study the effect of red blood cell (RBC) storage duration on long-term mortality in patients undergoing cardiac intervention.

BACKGROUND

RBCs undergo numerous structural and functional changes during storage. Observational studies have assessed the association between RBC storage duration and patient outcomes with conflicting results.

METHODS

Between January 2006 and December 2014, 82 408 patients underwent coronary angiography. Of these, 1856 patients received one to four RBC units within 30 days after this procedure. Patients were allocated according to length of RBC storage duration: short-term (≤11 days), intermediate (IM)-term (12-23 days) and long-term (≥24 days). The study endpoints were 30-day and long-term all-cause mortality.

RESULTS

A total of 4168 RBC units were given to 1856 patients. The mean RBC storage duration was 8.5 ± 2.1, 17.7 ± 3.4 and 29.9 ± 3.4 days in the short-term, IM-term and long-term storage groups, respectively. There was no difference in baseline characteristics between the groups. The long-term storage group received significantly more units (2.4 ± 1.0 units) as compared to the short-term (2.0 ± 1.0 units; P < 0.001) and IM-term storage group (2.2 ± 1.0 units; P < 0.01). In the survival analysis, there was no significant difference in all-cause mortality between the groups (log-rank: 0.509 for 30-days mortality; 0.493 for 5-year mortality). Additional stratified analysis demonstrated no association between RBC storage duration and long-term mortality.

CONCLUSION

This study did not find an association between RBC storage duration and 30-days or long-term mortality in patients undergoing cardiac intervention.