Position- and posture-dependent vascular imaging-a scoping review.

OBJECTIVES: Position- and posture-dependent deformation of the vascular system is a relatively unexplored field. The goal of this scoping review was to create an overview of existing vascular imaging modalities in different body positions and postures and address the subsequent changes in vascular anatomy. METHODS: Scopus, Medline, and Cochrane were searched for literature published between January 1, 2000, and June 30, 2022, incorporating the following categories: image modality, anatomy, orientation, and outcomes. RESULTS: Out of 2446 screened articles, we included 108. The majority of papers used ultrasound (US, n = 74) in different body positions and postures with diameter and cross-sectional area (CSA) as outcome measures. Magnetic resonance imaging (n = 22) and computed tomography (n = 8) were less frequently used but allowed for investigation of other geometrical measures such as vessel curvature and length. The venous system proved more sensitive to postural changes than the arterial system, which was seen as increasing diameters of veins below the level of the heart when going from supine to prone to standing positions, and vice versa. CONCLUSIONS: The influence of body positions and postures on vasculature was predominantly explored with US for vessel diameter and CSA. Posture-induced deformation and additional geometrical features that may be of interest for the (endovascular) treatment of vascular pathologies have been limitedly reported, such as length and curvature of an atherosclerotic popliteal artery during bending of the knee after stent placement. The most important clinical implications of positional changes are found in diagnosis, surgical planning, and follow-up after stent placement. CLINICAL RELEVANCE STATEMENT: This scoping review presents the current state and opportunities of position- and posture-dependent imaging of vascular structures using various imaging modalities that are relevant in the fields of clinical diagnosis, surgical planning, and follow-up after stent placement. KEY POINTS: • The influence of body positions and postures on the vasculature was predominantly investigated with US for vessel diameter and cross-sectional area. • Research into geometrical deformation, such as vessel length and curvature adaptation, that may be of interest for the (endovascular) treatment of vascular pathologies is limited in different positions and postures. • The most important clinical implications of postural changes are found in diagnosis, surgical planning, and follow-up after stent placement.

The Diagnostic Value of Biomarkers in Acute Mesenteric Ischaemia Is Insufficiently Substantiated: A Systematic Review.

OBJECTIVE: There is an urgent need for accurate biomarkers to support timely diagnosis of acute mesenteric ischaemia (AMI) and thereby improve clinical outcomes. With this systematic review, the aim was to substantiate the potential diagnostic value of biomarkers for arterial occlusive AMI. DATA SOURCES: The Pubmed, Embase, and the Cochrane Library electronic databases were searched. REVIEW METHODS: A systematic review of the literature has been conducted to define the potential diagnostic value of biomarkers for arterial occlusive AMI. All studies including ≥ 10 patients describing biomarkers for macrovascular occlusive AMI between 1950 and 17 February 2023 were identified within the Pubmed, Embase, and the Cochrane Library electronic databases. There were no restrictions to any particular study design, but letters and editorials were excluded. The QUADAS-2 tool was used for the critical appraisal of quality. The study protocol was registered on Prospero (CRD42021254970). RESULTS: Fifty of 4334 studies were eligible for inclusion in this review. Ninety per cent of studies were of low quality. A total of 60 biomarkers were identified, with 24 in two or more studies and 15 in five or more studies. There was variation in reported units, normal range, and cut off values. Meta-analysis was not possible due to study heterogeneity. Biomarkers currently recommended by the European Journal of Vascular and Endovascular Surgery, European Society for Trauma and Emergency Surgery 2016, and World Society of Emergency Surgery 2017 guidelines also had heterogeneous low quality data for use in the diagnosis of AMI. CONCLUSION: This systematic review demonstrates high heterogeneity and low quality of the available evidence on biomarkers for arterial occlusive AMI. No clinical conclusions can be drawn on a biomarker or combination of biomarkers for patients suspected of arterial occlusive AMI. Restraint is advised when rejecting or determining AMI solely based on biomarkers.

Factors associated with successful median arcuate ligament release in an international, multi-institutional cohort.

OBJECTIVE: Prior research on median arcuate ligament syndrome has been limited to institutional case series, making the optimal approach to median arcuate ligament release (MALR) and resulting outcomes unclear. In the present study, we compared the outcomes of different approaches to MALR and determined the predictors of long-term treatment failure. METHODS: The Vascular Low Frequency Disease Consortium is an international, multi-institutional research consortium. Data on open, laparoscopic, and robotic MALR performed from 2000 to 2020 were gathered. The primary outcome was treatment failure, defined as no improvement in median arcuate ligament syndrome symptoms after MALR or symptom recurrence between MALR and the last clinical follow-up. RESULTS: For 516 patients treated at 24 institutions, open, laparoscopic, and robotic MALR had been performed in 227 (44.0%), 235 (45.5%), and 54 (10.5%) patients, respectively. Perioperative complications (ileus, cardiac, and wound complications; readmissions; unplanned procedures) occurred in 19.2% (open, 30.0%; laparoscopic, 8.9%; robotic, 18.5%; P < .001). The median follow-up was 1.59 years (interquartile range, 0.38-4.35 years). For the 488 patients with follow-up data available, 287 (58.8%) had had full relief, 119 (24.4%) had had partial relief, and 82 (16.8%) had derived no benefit from MALR. The 1- and 3-year freedom from treatment failure for the overall cohort was 63.8% (95% confidence interval [CI], 59.0%-68.3%) and 51.9% (95% CI, 46.1%-57.3%), respectively. The factors associated with an increased hazard of treatment failure on multivariable analysis included robotic MALR (hazard ratio [HR], 1.73; 95% CI, 1.16-2.59; P = .007), a history of gastroparesis (HR, 1.83; 95% CI, 1.09-3.09; P = .023), abdominal cancer (HR, 10.3; 95% CI, 3.06-34.6; P < .001), dysphagia and/or odynophagia (HR, 2.44; 95% CI, 1.27-4.69; P = .008), no relief from a celiac plexus block (HR, 2.18; 95% CI, 1.00-4.72; P = .049), and an increasing number of preoperative pain locations (HR, 1.12 per location; 95% CI, 1.00-1.25; P = .042). The factors associated with a lower hazard included increasing age (HR, 0.99 per increasing year; 95% CI, 0.98-1.0; P = .012) and an increasing number of preoperative diagnostic gastrointestinal studies (HR, 0.84 per study; 95% CI, 0.74-0.96; P = .012) Open and laparoscopic MALR resulted in similar long-term freedom from treatment failure. No radiographic parameters were associated with differences in treatment failure. CONCLUSIONS: No difference was found in long-term failure after open vs laparoscopic MALR; however, open release was associated with higher perioperative morbidity. These results support the use of a preoperative celiac plexus block to aid in patient selection. Operative candidates for MALR should be counseled regarding the factors associated with treatment failure and the relatively high overall rate of treatment failure.

In Vivo Quantification of Cardiac-Pulsatility-Induced Motion Before and After Double-Branched Endovascular Aortic Arch Repair.

The Relay®Branch stent-graft (Terumo Aortic, Sunrise, FL, USA) offers a custom-made endovascular solution for complex aortic arch pathologies. In this technical note, a modified electrocardiography (ECG)-gated computed tomography (CT)-based algorithm was applied to quantify cardiac-pulsatility-induced changes of the aortic arch geometry and motion before and after double-branched endovascular repair (bTEVAR) of an aortic arch aneurysm. This software algorithm has the potential to provide novel and clinically relevant insights in the influence of bTEVAR on aortic anatomy, arterial compliance, and stent-graft dynamics.

Geometrical Changes of the Aorta as Predictors for Thromboembolic Events After EVAR With the Anaconda Stent-Graft.

PURPOSE: Thromboembolic events (TE), including limb graft occlusion (LGO) and distal limb embolization (DLE), are common complications after endovascular aneurysm repair (EVAR). The aim of this study was to find predictors for TE in patients treated with the Anaconda stent-graft for infrarenal aneurysms. MATERIALS AND METHODS: Geometrical and anatomical variables were retrospectively analyzed in a consecutive Anaconda cohort. Pre- and postoperative CT scans were used to derive geometrical parameters length, curvature, torsion, and tortuosity index (TI) from the center lumen lines (CLLs). Limb characteristics, pre-to-post EVAR and mid-term-follow-up changes in the parameters were evaluated for their predictive value for TE. RESULTS: Eighty-four patients (mean age 74±8.3 years, 74 men) were enrolled. The risk of TE was lowered with pre-to-post implant decreasing TI (steps of 0.05: OR: 1.30, 95% CI: 1.01-1.66, p=0.04), pre-to-post implant decreasing mean curvature (OR: 1.08, 95% CI: 1.01-1.16, p=0.03), and a larger degree of circumferential common iliac artery (CIA) calcification (OR: 0.98, 95% CI: 0.97-1.00, p=0.03). The only LGO predictor was the caudal relocation of maximal curvature after EVAR (OR: 1.01, 95% CI: 1.00-1.01, p=0.04). Preventors of DLE were CIA diameter (OR: 0.87, 95% CI: 0.76-0.99, p=0.04), circumferential CIA calcification (OR: 0.97, 95% CI: 0.95-1.00, p=0.03), mean and maximal curvature of the preoperative aortoiliac trajectory (OR: 0.86, 95% CI: 0.79-0.94, p<0.01 and OR: 0.97, 95% CI: 0.95-1.00, p=0.03, respectively) and pre-to-postoperative decrease in mean curvature (OR: 1.11, 95% CI: 1.02-1.21, p=0.02). Midterm TE predictors were length (OR: 0.95, 95% CI: 0.89-1.01, p=0.08) and torsion maximum location (OR: 1.01, 95% CI: 0.99-1.01, p=0.10). CONCLUSION: The present study confirms that treatment of infrarenal AAA with an Anaconda stent-graft is related to a relatively high TE rate which decreases with a pre-to-postoperative reduction in curvature and TI, and a larger degree of circumferential CIA calcification. In other words, more aortoiliac straightening and more circumferential CIA calcification may prevent TE development after EVAR with this stent-graft.

Renal and Visceral Artery Configuration During the First Year of Follow-Up After Fenestrated Aortic Aneurysm Repair Using the Anaconda Stent-graft: A Prospective Longitudinal Multicenter Study With ECG-Gated CTA Scans.

OBJECTIVE: The performance of fenestrated endovascular aortic aneurysm repair (FEVAR) may be compromised by complications related to the dynamic vascular environment. The aim of this study was to analyze the behavior of FEVAR bridging stent configurations during the cardiac cycle and during follow-up to improve our understanding on treatment durability. DESIGN: Twenty-one patients presenting with complex abdominal aortic aneurysms (AAAs; 9 juxtarenal/6 pararenal/3 paravisceral/1 thoracoabdominal aortic aneurysm type IV), treated with a fenestrated Anaconda (Terumo Aortic, Inchinnan, Scotland, UK) with Advanta V12 bridging stents (Getinge, Merrimack, NH, USA), were prospectively enrolled in a multicenter observational cohort study and underwent electrocardiogram (ECG)-gated computed tomographic angiography (CTA) preoperatively, at discharge, 7-week, and 12-month follow-ups. METHODS: Fenestrated endovascular aortic aneurysm repair stability was assessed considering the following variables: branch angle as the angle between the aorta and the target artery, end-stent angle as the angle between the end of the bridging stent and the native artery downstream from it, curvature and tortuosity index (TI) to describe the bending of the target artery. Body-bridging stent stability was assessed considering bridging stent flare lengths, the distances between the proximal sealing stent-ring and fenestrations and the distance between the fenestration and first apposition in the target artery. RESULTS: Renal branch angles significantly increased after FEVAR toward a perpendicular position (right renal artery from median 60.9°, inter quartile range [IQR]=44.2-84.9° preoperatively to 94.4°, IQR=72.6-99.8°, p=0.001 at 12-month follow-up; left renal artery [LRA], from 63.7°, IQR=55.0-73.0° to 94.3°, IQR=68.2-105.6°, p<0.001), while visceral branch angles did not. The mean dynamic curvature only decreased for the LRA from preoperative (3.0, IQR=2.2-3.8 m-1) to 12-month follow-up (1.9, IQR=1.4-2.6 m-1, p=0.027). The remaining investigated variables did not seem to show any changes over time in this cohort. CONCLUSIONS: Fenestrated endovascular aortic aneurysm repair for complex AAAs using the Anaconda fenestrated stent-graft and balloon-expandable Advanta V12 bridging stents demonstrated stable configurations up to 12-month follow-up, except for increasing renal branch angles toward perpendicular orientation to the aorta, yet without apparent clinical consequences in this cohort. CLINICAL IMPACT: This study provides detailed information on the cardiac-pulsatility-induced (dynamic) and longitudinal geometry deformations of the target arteries and bridging stents after fenestrated endovascular aortic aneurysm repair (FEVAR) up to 12-month follow-up. The configuration demonstrated limited dynamic and longitudinal deformations in terms of branch angle, end-stent angle, curvature, and tortuosity index (TI), except for the increasing renal branch angles that go toward a perpendicular orientation to the aorta. Overall, the results suggest that the investigated FEVAR configurations are stable and durable, though careful consideration of increasing renal branch angles and significant geometry alterations is advised.

Ultrasound Particle Image Velocimetry to Investigate Potential Hemodynamic Causes of Limb Thrombosis After Endovascular Aneurysm Repair With the Anaconda Device.

PURPOSE: To identify potential hemodynamic predictors for limb thrombosis (LT) following endovascular aneurysm repair with the Anaconda endograft in a patient-specific phantom. MATERIALS AND METHODS: A thin-walled flow phantom, based on a patient's aortic anatomy and treated with an Anaconda endograft, that presented with a left-sided LT was fabricated. Contrast-enhanced ultrasound particle image velocimetry was performed to quantify time-resolved velocity fields. Measurements were performed in the same phantom with and without the Anaconda endograft, to investigate the impact of the endograft on the local flow fields. Hemodynamic parameters, namely vector complexity (VC) and residence time (RT), were calculated for both iliac arteries. RESULTS: In both limbs, the vector fields were mostly unidirectional during the peak systolic and end-systolic velocity phases before and after endograft placement. Local vortical structures and complex flow fields were observed at the diastolic and transitional flow phases. The average VC was higher (0.11) in the phantom with endograft, compared to the phantom without endograft (0.05). Notably, in both left and right iliac arteries, the anterior wall regions corresponded to a 2- and 4-fold increase in VC in the phantom with endograft, respectively. RT simulations showed values of 1.3 to 6 seconds in the phantom without endograft. A higher RT (up to 25 seconds) was observed in the phantom with endograft, in which the left iliac artery, with LT in follow-up, showed 2 fluid stasis regions. CONCLUSION: This in vitro study shows that unfavorable hemodynamics were present mostly in the limb that thrombosed during follow-up, with the highest VC and longest RT. These parameters might be valuable in predicting the occurrence of LT in the future. CLINICAL IMPACT: This in-vitro study aimed to identify potential hemodynamic predictors for limb thrombosis following EVAR using ultrasound particle image velocimetry (echoPIV) technique. It was shown that unfavorable hemodynamic norms were present mostly in the thrombosed limb. Owing to the in-vivo feasibility of the echoPIV, future efforts should focus on the evaluation of these hemodynamic norms in clinical trials. Thereafter, using echoPIV as a bedside technique in hospitals becomes more promising. Performing echoPIV in pre-op phase may provide valuable insights for surgeons to enhance treatment planning. EchoPIV is also applicable for follow-up sessions to evaluate treatment progress and avoid/predict complications.

A Systematic Review of Endovascular Repair Outcomes in Atherosclerotic Chronic Mesenteric Ischaemia.

OBJECTIVE: Chronic mesenteric ischaemia (CMI) treatment focuses on symptom relief and prevention of disease progression. Endovascular repair represents the main treatment modality, while data on the associated antiplatelet regimen are scarce. The aim of this meta-analysis was to assess the early and midterm outcomes of endovascular repair in patients with CMI. DATA SOURCES: Randomised controlled trials and observational studies (1990 - 2022) reporting on early and midterm endovascular repair outcomes in patients with atherosclerotic CMI. REVIEW METHODS: The PRISMA guidelines and PICO model were followed. The protocol was registered to PROSPERO (CRD42023401685). Medline, Embase (via Ovid), and Cochrane databases were searched (end date 21 February 2023). The Newcastle-Ottawa Scale was used for risk of bias assessment, and GRADE for evidence quality assessment. Primary outcomes were technical success, 30 day mortality, and symptom relief, assessed using prevalence meta-analysis. The role of dual antiplatelet therapy (DAPT) was investigated using meta-regression analysis. RESULTS: Sixteen retrospective studies (1 224 patients; mean age 69.8 ± 10.6 years; 60.3% female) reporting on 1 368 target vessels (57.8% superior mesenteric arteries) were included. Technical success was 95.0% (95% CI 93 - 97%, p = .28, I2 19%, low certainty), the 30 day mortality rate was 2.0% (95% CI 2 - 4%, p = .93, I2 36%, low certainty), and immediate symptom relief was 87.0% (95% CI 80 - 92%, p < .010, I2 85%, very low certainty). At mean follow up of 28 months, the mortality rate was 15.0% (95% CI 9 - 25%, p = .010, I2 86%, very low certainty), symptom recurrence 25.0% (95% CI 21 - 31%, p < .010, I2 68%, very low certainty) and re-intervention rate 26.0% (95% CI 17 - 37%, p < .010, I2 92%, very low certainty). Single antiplatelet therapy (SAPT) and DAPT performed similarly in the investigated outcomes. CONCLUSION: Endovascular repair for CMI appears to be safe as first line treatment, with a low peri-operative mortality rate and acceptable immediate symptom relief. During midterm follow up, symptom recurrence and need for re-intervention are not uncommon. SAPT appears to be equal to DAPT in post-operative outcomes.

Robot-assisted and fluorescence-guided remnant-cholecystectomy: a prospective dual-center cohort study.

BACKGROUND: Abdominal symptoms after cholecystectomy may be caused by gallstones in a remnant gallbladder or a long cystic duct stump. Resection of a remnant gallbladder or cystic duct stump is associated with an increased risk of conversion and bile duct or vascular injuries. We prospectively investigated the additional value of robotic assistance and fluorescent bile duct illumination in redo biliary surgery. METHODS: In this prospective two-centre observational cohort study, 28 patients were included with an indication for redo biliary surgery because of remnant stones in a remnant gallbladder or long cystic duct stump. Surgery was performed with the da Vinci X® and Xi® robotic system. The biliary tract was visualised in the fluorescence Firefly® mode shortly after intravenous injection of indocyanine green. RESULTS: There were no conversions or perioperative complications, especially no vascular or bile duct injuries. Fluorescence-based illumination of the extrahepatic bile ducts was successful in all cases. Symptoms were resolved in 27 of 28 patients. Ten patients were treated in day care and 13 patients were discharged the day after surgery. CONCLUSION: Robot-assisted fluorescence-guided surgery for remnant gallbladder or cystic duct stump resection is safe, effective and can be done in day-care setting.

Incidence and predictive factors for endograft limb patency of the fenestrated Anaconda endograft used for complex endovascular aneurysm repair.

OBJECTIVE: In the present study, we have described the incidence, risk factors, and outcomes of treatment of limb occlusion for patients who had undergone treatment of complex thoracoabdominal aortic aneurysms with the fenestrated Anaconda endograft (Terumo Aortic, Inchinnan, UK). METHODS: Between June 2010 and May 2018, 335 patients had undergone elective fenestrated aortic aneurysm repair at 11 participating centers using the fenestrated Anaconda endograft with a median follow-up of 14.3 months (interquartile range, 27.4 months). The primary outcome measure was freedom from limb occlusion. The secondary outcome measures were freedom from limb-related reintervention, secondary patency, and the risk factors associated with limb occlusion. RESULTS: Of the 335 patients, 30 (9.0%) had presented with limb occlusion during follow-up with a freedom from limb occlusion rate of 98.5%, 91.2%, and 81.7% at 30 days and 1 and 5 years, respectively. In 87% of the cases, no obvious cause for limb occlusion was documented. Primary occlusion had occurred within 30 days in 36.7% and within 1 year in 80.0%. Of the 30 patients, 23 (77%) had undergone an occlusion-related reintervention and 7 (23.3%) had been treated conservatively. The freedom from limb occlusion-related reintervention at 30 days and 1 and 5 years was 97.8%, 93.2%, and 88.6%, respectively. Secondary patency was 91.3% after 1 month and 86.2% after 1 and 5 years. Female sex (odds ratio [OR], 3.27; 95% confidence interval [CI], 1.28-8.34; P = .01) was a statistically significant predictor for limb occlusion. A greater proportion of thrombus in the aneurysm sac appeared to be protective for limb occlusion (0% vs <25%: OR, 0.22; 95% CI, 0.07-0.63; P = .01; 0% vs 25%-50%: OR, 0.20; 95% CI, 0.07-0.57; P = .00; and 0% vs >50%: OR, 0.08; 95% CI, 0.02-0.38; P = .00), as did iliac angulation (OR, 0.99; 95% CI, 0.98-1.00; P = .04). CONCLUSIONS: Limb occlusion remains a significant impediment of endograft durability for patients treated with the fenestrated Anaconda endograft, especially for female patients. In contrast, a high aneurysmal thrombus load and a high degree of iliac angulation appeared to be protective for limb occlusion, for which no obvious cause could be identified.

Systematic Review of the Efficacy of Treatment for Median Arcuate Ligament Syndrome.

OBJECTIVE: Since the first description of the median arcuate ligament syndrome (MALS), the existence for the syndrome and the efficacy of treatment for it have been questioned. METHODS: A systematic review conforming to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement was conducted, with a broader view on treatment for MALS including any kind of coeliac artery release, coeliac plexus resection, and coeliac plexus blockage, irrespective of age. Online databases were used to identify papers published between 1963 and July 2021. The inclusion criteria were abdominal symptoms, proof of MALS on imaging, and articles reporting at least three patients. Primary outcomes were symptom relief and quality of life (QoL). RESULTS: Thirty-eight studies describing 880 adult patients and six studies describing 195 paediatric patients were included. The majority of the adult studies reported symptom relief of more than 70% from three to 228 months after treatment. Two adult studies showed an improved QoL after treatment. Half of the paediatric studies reported symptom relief of more than 70% from six to 62 months after laparoscopic coeliac artery release, and four studies reported an improved QoL. Thirty-five (92%) adult studies and five (83%) paediatric studies scored a high or unclear risk of bias for the majority of the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) items. The meaning of coeliac plexus resection or blockage could not be substantiated. CONCLUSION: This systematic review suggests a sustainable symptom relief of more than 70% after treatment for MALS in the majority of adult and paediatric studies; however, owing to the heterogeneity of the inclusion criteria and outcome parameters, the risk of bias was high and a formal meta-analysis could not be performed. To improve care for patients with MALS the next steps would be to deal with reporting standards, outcome definitions, and consensus descriptions of the intervention(s), after which an appropriate randomised controlled trial should be performed.

Treatment Outcome Trends for Non-Ruptured Abdominal Aortic Aneurysms: A Nationwide Prospective Cohort Study.

OBJECTIVE: The Dutch Surgical Aneurysm Audit (DSAA) initiative was established in 2013 to monitor and improve nationwide outcomes of aortic aneurysm surgery. The objective of this study was to examine whether outcomes of surgery for intact abdominal aortic aneurysms (iAAA) have improved over time. METHODS: Patients who underwent primary repair of an iAAA by standard endovascular (EVAR) or open surgical repair (OSR) between 2014 and 2019 were selected from the DSAA for inclusion. The primary outcome was peri-operative mortality trend per year, stratified by OSR and EVAR. Secondary outcomes were trends per year in major complications, textbook outcome (TbO), and characteristics of treated patients. The trends per year were evaluated and reported in odds ratios per year. RESULTS: In this study, 11 624 patients (74.8%) underwent EVAR and 3 908 patients (25.2%) underwent OSR. For EVAR, after adjustment for confounding factors, there was no improvement in peri-operative mortality (aOR [adjusted odds ratio] 1.06, 95% CI 0.94 - 1.20), while major complications decreased (2014: 10.1%, 2019: 7.0%; aOR 0.91, 95% CI 0.88 - 0.95) and the TbO rate increased (2014: 68.1%, 2019: 80.9%; aOR 1.13, 95% CI 1.10 - 1.16). For OSR, the peri-operative mortality decreased (2014: 6.1%, 2019: 4.6%; aOR 0.89, 95% CI 0.82 - 0.98), as well as major complications (2014: 28.6%, 2019: 23.3%; aOR 0.95, 95% CI 0.91 - 0.99). Furthermore, the proportion of TbO increased (2014: 49.1%, 2019: 58.3%; aOR 1.05, 95% CI 1.01 - 1.10). In both the EVAR and OSR group, the proportion of patients with cardiac comorbidity increased. CONCLUSION: Since the establishment of this nationwide quality improvement initiative (DSAA), all outcomes of iAAA repair following EVAR and OSR have improved, except for peri-operative mortality following EVAR which remained unchanged.

Real World Practice Deviation from Nationwide Guidelines in Patients with Intermittent Claudication.

OBJECTIVE: Patients with intermittent claudication (IC) are initially treated with supervised exercise therapy (SET), as advised by national and international guidelines. Dutch health insurance companies and the Dutch National Health Care Institute suggested an 87% compliance rate with these guidelines in the Netherlands in 2017 and judged this to be undesirably low. The aim of this study was to evaluate compliance with IC guidelines and to elaborate on the reasons for deviating from them (practice variation) in a large teaching hospital. METHODS: A retrospective single centre cohort study was conducted at a large teaching hospital in the Netherlands. In total, 420 patients with newly diagnosed IC between 1 January 2017 and 31 December 2018 were analysed. Data included risk profiles and prescribed therapies. RESULTS: For all 420 included patients, the compliance rate with the guidelines for SET was 80.5%. The rate of adequately motivated and defensible practice variation was 15.7%; the rate of unjustified practice variation was 3.8%. Meaningful care was seen in 96.2% of cases. CONCLUSION: Deviation from IC guidelines was found in 19.5% of patients. Almost three quarters of this deviation can be explained by the decision to provide personalised, meaningful care.

A Systematic Review and Critical Appraisal of Peri-Procedural Tissue Perfusion Techniques and their Clinical Value in Patients with Peripheral Arterial Disease.

OBJECTIVE: Many techniques have been introduced to enable quantification of tissue perfusion in patients with peripheral arterial disease (PAD). Currently, none of these techniques is widely used to analyse real time tissue perfusion changes during endovascular or surgical revascularisation procedures. The aim of this systematic review was to provide an up to date overview of the peri-procedural applicability of currently available techniques, diagnostic accuracy of assessing tissue perfusion and the relationship with clinical outcomes. DATA SOURCES: MEDLINE, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials. REVIEW METHODS: This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic review and Meta-Analysis (PRISMA) guidelines. Four electronic databases were searched up to 31 12 2020 for eligible articles: MEDLINE, Embase, CINAHL and the Cochrane Central Register of Controlled Trials. Eligible articles describing a perfusion measurement technique, used in a peri-procedural setting before and within 24 hours after the revascularisation procedure, with the aim of determining the effect of intervention in patients with PAD, were assessed for inclusion. The QUADAS-2 tool was used to assess the risk of bias and applicability of the studies. RESULTS: An overview of 10 techniques found in 26 eligible articles focused on study protocols, research goals, and clinical outcomes is provided. Non-invasive techniques included laser speckle contrast imaging, micro-lightguide spectrophotometry, magnetic resonance imaging perfusion, near infrared spectroscopy, skin perfusion pressure, and plantar thermography. Invasive techniques included two dimensional perfusion angiography, contrast enhanced ultrasound, computed tomography perfusion imaging, and indocyanine green angiography. The results of the 26 eligible studies, which were mostly of poor quality according to QUADAS-2, were without exception, not sufficient to substantiate implementation in daily clinical practice. CONCLUSION: This systematic review provides an overview of 10 tissue perfusion assessment techniques for patients with PAD. It seems too early to appoint one of them as a reference standard. The scope of future research in this domain should therefore focus on clinical accuracy, reliability, and validation of the techniques.

Electrocardiography-gated computed tomography angiography analysis of cardiac pulsatility-induced motion and deformation after endovascular aneurysm sealing with chimney grafts.

OBJECTIVE: To evaluate the proximal stability of the chimney endovascular aneurysm sealing configuration (chEVAS) during the cardiac cycle by investigating the cardiac pulsatility-induced movement and deformation. METHODS: We retrospectively analyzed postoperative electrocardiogram-gated computed tomography angiography scans of 11 chEVAS cases (9 primary chEVAS plus 2 chEVAS-in-chEVAS). ChEVAS procedures were conducted between September 2013 and June 2016. Motion and deformation of the EVAS stents, the chimney grafts, and the stented branch vessels were evaluated during the cardiac cycle using an established combination of image registration and segmentation techniques. RESULTS: Electrocardiogram-gated computed tomography angiography scans of 11 chEVAS configurations including 22 EVAS stents and 20 chimney grafts were analyzed. The three-dimensional displacement was at most 1.7 mm for both the EVAS stents and the chimney grafts. The maximum change in distance between components was no more than 0.4 mm and did not differ between EVAS-to-EVAS stent and EVAS stent-to-chimney stent (0.2 ± 0.1 mm vs 0.2 ± 0.1 mm; P = .823). The mean change in chimney deflection angle was 1.2 ± 0.7°; the maximum change was greatest for the superior mesenteric artery (SMA) (2.6°). The EVAS stent-to-chimney angles for the left renal artery, right renal artery, and SMA varied on average by 0.7 ± 0.3° (range, 0.4°-1.3°), 1.0 ± 0.3° (range, 0.5°-1.7°), and 0.8 ± 0.4° (range, 0.3°-1.3°), respectively, during the cardiac cycle. The end-stent angles for the left renal artery, right renal artery, and SMA varied on average by 1.7 ± 0.9° (range, 0.5°-3.3°), 1.9 ± 0.8° (range, 0.7°-3.3°), and 1.3 ± 0.4° (range, 0.7°-1.6°), respectively, during the cardiac cycle. Overall, the end-stent angles varied on average by 1.7 ± 0.8° (range, 0.5°-3.3°). CONCLUSIONS: The chEVAS configuration proved to be stable during the cardiac cycle, as demonstrated by minimal cyclical changes in distance between device components and angulation between the EVAS stents and the chimney grafts. The limited deflection angles of the chimney grafts decrease the risk of bending fatigue, but the more apparent change in end-stent angle distal to the chimney graft may raise concerns regarding late branch occlusion or stenosis.

Radiation exposure in an endovascular aortic aneurysm repair program after introduction of a hybrid operating theater.

BACKGROUND: A hybrid operating theater (HOT) enables optimal image quality, improved ergonomics, and excellent sterility for complex endovascular and hybrid procedures. We hypothesize that the commissioning of a new HOT involves a learning curve. It is unclear how steep the learning curve of these advanced HOTs is. The main purpose of this research was to evaluate radiation exposure parameters in a new HOT for a team of vascular surgeons experienced with infrarenal endovascular aneurysm repair (EVAR) procedures in a conventional operating room with a mobile C-arm. In addition, a comparison of the dose-area product (DAP) achieved in this study and in the literature was made. METHODS: Before commissioning of the HOT, four vascular surgeons completed a comprehensive HOT training program. From the commissioning of the HOT, clinical and procedural data for all consecutive acute and elective patients treated with EVAR were retrospectively collected for a period of 18 months (January 2016-June 2017). A literature review was conducted of the dose-area product in EVAR procedures performed with a dedicated fixed system or mobile C-arm to analyze how this study performed compared with the literature. RESULTS: In the 18-month study period, 77 patients were treated with EVAR (59 electively and 18 acutely), from whom the data were obtained. There was no significant change in radiation exposure parameters over time. From the commissioning of the HOT, EVAR procedures were performed with radiation exposure parameters similar to those of studies found in experienced vascular centers using fixed systems. CONCLUSIONS: Concerning radiation exposure parameters, the commissioning of a new HOT was not accompanied by a learning curve. Radiation exposure parameters achieved in this study were similar to those of studies from experienced and dedicated vascular centers.

Geometric Remodeling of the Perirenal Aortic Neck at and Adjacent to the Double Sealing Ring of the Anaconda Stent-Graft After Endovascular Aneurysm Repair.

Purpose: To evaluate if the radial force of the double sealing ring of the Anaconda stent-graft induces dilatation in the perirenal aortic neck adjacent to the rings. Materials and Methods: This study evaluated the serial electrocardiogram-gated computed tomography scans of 15 abdominal aortic aneurysm patients (mean age 72.8±3.7 years; 14 men) who were treated electively using an Anaconda stent-graft. Follow-up scans were conducted before discharge and at 1, 6, 12, and 24 months after endovascular repair. Diameter and area were assessed perpendicular to the aortic centerline along the perirenal aortic neck, which was subdivided into 3 zones: the suprastent, the stent, and the infrastent zones. Measurements were performed independently by 2 experienced observers using dedicated 3-dimensional image processing software. Results: Between discharge and the 2-year follow-up the diameter and area remained stable in the suprastent zone [average diameter change: -0.1±0.4 mm (-0.4%±1.7%), p=0.893; average area change: -2.9±17.2 mm2 (-0.7%±3.4%), p=0.946], increased in the stent zone [average diameter change: +1.9±1.0 mm (+7.3%±4.0%), p<0.001; average area change: +84.3±48.3 mm2 (+15.5%±8.7%), p<0.001], and diverged in the infrastent zone [average diameter change: -0.8±2.2 mm (-2.3%±7.4%), p>0.99; average area change: -34.6±102.3 mm2 (-4.1%±14.8%), p>0.99; increased in 4 patients, decreased in 9 patients]. Conclusion: After Anaconda implantation the infrarenal aortic neck accommodated to the expansion of the sealing rings at the stent zone. Below the stent zone the neck diameter decreased in the majority of patients, while an increase was related to downstream displacement of the main body. A decrease in size in the infrastent zone may contribute to durable sealing and fixation. A personalized follow-up scheme based on geometric neck remodeling should be feasible if our observations are confirmed in larger, long-term studies.

Incidence and Treatment of Limb Occlusion of the Anaconda Endograft After Endovascular Aneurysm Repair.

PURPOSE: To evaluate the incidence and treatment of limb occlusions of the second- and third-generation Anaconda endografts. METHODS: A single-center retrospective study was conducted involving 317 consecutive patients (mean age 76 years; 289 men) who underwent endovascular aneurysm repair for elective asymptomatic, symptomatic intact, and ruptured infrarenal abdominal aortic aneurysm with 2 versions of the Anaconda device. From September 2003 to July 2011, the second-generation device was used in 189 patients (mean age 77 years; 169 men) and from July 2011 to September 2015, the third-generation device was implanted in 128 patients (mean age 75 years; 120 men). The rates of limb occlusion were compared between groups and according to compliance with the instructions for use (IFU); predictors were sought in multivariate analysis. The results of the latter are given as the hazard ratio (HR) and 95% confidence interval (CI). RESULTS: Kaplan-Meier freedom of occlusion estimates for second- and third-generation devices, respectively, was 96.6% and 95.0% at 1 year, 89.9% and 95.0% at 2 years, and 86.5% and 88.6% at 5 years. There was no significant difference in overall occlusion rate between the second-generation devices (p=0.332) or with regard to use within the IFU (p=0.827); however, there was a clinically relevant decrease in the occlusion rate for elective patients treated with the third-generation device (6.4% vs 13.1%, p=0.077). There was an increase in the occlusion rate when the iliac limb diameter was ≤13 mm. In multivariate analysis, the only independent predictor of limb occlusion was a small distal prosthesis diameter (HR 0.732, 95% CI 0.63 to 0.86, p<0.001). Symptomatic nonruptured and ruptured abdominal aortic aneurysm (AAA) interventions had an almost 2-fold increased risk of occlusion (HR 1.95, 95% CI 0.93 to 4.11, p=0.078), though this did not reach statistical significance. CONCLUSION: The Anaconda design has proven effectiveness in AAA exclusion in daily practice inside the IFU. However, efforts could be made to further reduce the limb occlusion rate.

Quantitative Stent Graft Motion in ECG Gated CT by Image Registration and Segmentation: In Vitro Validation and Preliminary Clinical Results.

OBJECTIVES: The dynamic endovascular environment of stent grafts may influence long term outcome after endovascular aneurysm repair (EVAR). The sealing and fixation of a stent graft to the aortic wall is challenged at every heartbeat, yet knowledge of the cardiac induced dynamics of stent grafts is sparse. Understanding the stent-artery interaction is crucial for device development and may aid the prediction of failure in the individual patient. The aim of this work was to establish quantitative stent graft motion in multiphasic electrocardiogram (ECG) gated computed tomography (CT) by image registration and segmentation techniques. METHODS: Experimental validation was performed by evaluating a series of ECG gated CT scans of a stent graft moving at different amplitudes of displacement at different virtual heart rates using a motion generating device with synchronised ECG triggering. The methodology was further tested on clinical data of patients treated with EVAR devices with different stent graft designs. Displacement during the cardiac cycle was analysed for points on the fixating stent rings, the branches or fenestrations, and the spine. RESULTS: Errors for the amplitude of displacement measured in vitro at individual points on the wire frame were at most 0.3 mm. In situ cardiac induced displacement of the devices was found to differ per location and also depended on the type of stent graft. Displacement during the cardiac cycle was greatest in a fenestrated device and smallest in a chimney graft sac anchoring endosystem, with maximum displacement varying from 0.0 to 1.4 mm. There was no substantial displacement measurable in the spine. CONCLUSIONS: A novel methodology to quantify and visualise stent graft motion in multiphasic ECG gated CT has been validated in vitro and tested in vivo. This methodology enables further exploration of in situ motion of different stent grafts and branch stents and their interaction with native vessels.

Evolution of the Proximal Sealing Rings of the Anaconda Stent-Graft After Endovascular Aneurysm Repair.

PURPOSE: To provide insight into the evolution of the saddle-shaped proximal sealing rings of the Anaconda stent-graft after endovascular aneurysm repair (EVAR). METHODS: Eighteen abdominal aortic aneurysm patients were consecutively enrolled in a single-center, prospective, observational cohort study (LSPEAS; Trialregister.nl identifier NTR4276). The patients were treated electively using an Anaconda stent-graft with a mean 31% oversizing (range 17-47). According to protocol, participants were to be followed for 2 years, during which 5 noncontrast electrocardiogram-gated computed tomography scans would be conducted. Three patients were eliminated within 30 days (1 withdrew, 1 died, and a third was converted before stent-graft deployment), leaving 15 patients (mean age 72.8±3.7 years; 14 men) for this analysis. Evolution in size and shape (symmetry) of both proximal infrarenal sealing rings were assessed from discharge to 24 months using dedicated postprocessing algorithms. RESULTS: At 24 months, the mean diameters of the first and second ring stents had increased significantly (first ring: 2.2±1.0 mm, p<0.001; second ring: 2.7±1.1 mm, p<0.001). At 6 months, the first and second rings had expanded to a mean 96.6%±2.1% and 94.8%±2.7%, respectively, of their nominal diameter, after which the rings expanded slowly; ring diameters stabilized to near nominal size (first ring, 98.3%±1.1%; second ring, 97.2%±1.4%) at 24 months irrespective of initial oversizing. No type I or III endoleaks or aneurysm-, device-, or procedure-related adverse events were noted in follow-up. The difference in the diametric distances between the peaks and valleys of the saddle-shaped rings was marked at discharge but became smaller after 24 months for both rings (first ring: median 2.0 vs 1.2 mm, p=0.191; second ring: median 2.8 vs 0.8 mm; p=0.013). CONCLUSION: Irrespective of initial oversizing, the Anaconda proximal sealing rings radially expanded to near nominal size within 6 months after EVAR. Initial oval-shaped rings conformed symmetrically and became nearly circular through 24 months. These findings should be taken into account in planning and follow-up.