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.

Three-Dimensional Geometric Analysis of Viabahn VBX Bridging Stent Grafts in Fenestrated Endovascular Aortic Repair: A Multicenter, Retrospective Cohort Study.

PURPOSE: The primary aim of this study was to assess the 3-dimensional flare geometry of the Gore Viabahn VBX balloon-expandable covered stent (BECS) after fenestrated endovascular aortic repair (FEVAR) and to determine and visualize BECS-associated complications. METHODS: This multicenter retrospective study included patients who underwent FEVAR between 2018 and 2022 in 3 vascular centers participating in the VBX Expand Registry. Patients with at least one visceral artery treated with the VBX and with availability of 2 post-FEVAR computed tomography angiography (CTA) scans (follow-up [FU] 1: 0-6 months; FU2: 9-24 months) were included. The flare geometry of the VBX, including flare-to-fenestration distance, flare-to-fenestration diameter ratio, flare angle, and apposition with the target artery were assessed using a vascular workstation and dedicated CTA applied software. RESULTS: In total, 90 VBX BECS were analyzed in 43 FEVAR patients. The median CTA FU for FU1 and FU2 was 35 days (interquartile range [IQR], 29-51 days) and 14 months (IQR, 13-15 months), respectively. The mean flare-to-fenestration distance was 5.6±2.0 mm on FU1 and remained unchanged at 5.7±2.0 mm on FU2 (p=.417). The flare-to-fenestration diameter ratio was 1.19±0.17 on FU1 and remained unchanged at 1.21±0.19 (p=.206). The mean apposition length was 18.6±5.3 mm on FU1 and remained 18.6±5.3 mm (p=.550). The flare angle was 31°±15° on FU1 and changed to 33°±16° (p=.009). On FU1, the BECS-associated complication rate was 1%, and the BECS-associated reintervention rate was 0%. On FU2, the BECS-associated complication rate was 3%, and the BECS-associated reintervention rate was 1%. CONCLUSIONS: The flare geometry of the VBX bridging stent did not change significantly during 14 months follow-up in this study. Three-dimensional geometric analysis of the flare may contribute to identify the origin of endoleaks and occlusions, but this should be confirmed in a larger study including enough patients and BECS to compare complicated and uncomplicated cases. CLINICAL IMPACT: The three-dimensional flare geometry of the Gore Viabahn VBX BECS was assessed on the first and second postoperative CTA scans, and geometrical changes during this period were identified. For BECS that were diagnosed with a type 3c endoleak or occlusion, the BECS geometry was analyzed to detect geometrical components that were related to the complication. Geometric analysis of the flare may help to better detect and identify the cause of such complications.

Machine Learning Based Prediction of Post-operative Infrarenal Endograft Apposition for Abdominal Aortic Aneurysms.

OBJECTIVE: Challenging infrarenal aortic neck characteristics have been associated with an increased risk of type Ia endoleak after endovascular aneurysm repair (EVAR). Short apposition (< 10 mm circumferential shortest apposition length [SAL]) on the first post-operative computed tomography angiography (CTA) has been associated with type Ia endoleak. Therefore, this study aimed to develop a model to predict post-operative SAL in patients with an abdominal aortic aneurysm based on the pre-operative shape. METHODS: A statistical shape model was developed to obtain principal component scores. The dataset comprised patients treated by standard EVAR without complications (n = 93) enriched with patients with a late type Ia endoleak (n = 54). The infrarenal SAL was obtained from the first post-operative CTA and subsequently binarised (< 10 mm and ≥ 10 mm). The principal component scores that were statistically different between the SAL groups were used as input for five classification models, and evaluated by means of leave one out cross validation. Area under the receiver operating characteristic curves (AUC), accuracy, sensitivity, and specificity were determined for each classification model. RESULTS: Of the 147 patients, 24 patients had an infrarenal SAL < 10 mm and 123 patients had a SAL ≥ 10 mm. The gradient boosting model resulted in the highest AUC of 0.77. Using this model, 114 patients (77.6%) were correctly classified; sensitivity (< 10 mm apposition was correctly predicted) and specificity (≥ 10 mm apposition was correctly predicted) were 0.70 and 0.79 based on a threshold of 0.21, respectively. CONCLUSION: A model was developed to predict which patients undergoing EVAR will achieve sufficient graft apposition (≥ 10 mm) in the infrarenal aortic neck based on a statistical shape model of pre-operative CTA data. This model can help vascular specialists during the planning phase to accurately identify patients who are unlikely to achieve sufficient apposition after standard EVAR.

Geometric Analysis of the Gore Excluder Conformable Endoprosthesis in the Infrarenal Aortic Neck: One Year Results of the EXCeL Registry.

OBJECTIVE: The Gore Excluder Conformable Endoprosthesis (CEXC) is designed to treat challenging infrarenal anatomy because of its active angulation control, repositionability, and enhanced conformability. This study evaluated 30 day and one year position and apposition of the CEXC in the infrarenal neck. METHODS: Patients treated with the CEXC between 2018 and 2022 with an available 30 day computed tomography angiogram (CTA) were selected from four hospitals in a prospective registry. Endograft apposition (shortest apposition length [SAL]) and position (shortest fabric distance [SFD]) were assessed on the 30 day and one year CTAs. Maximum infrarenal aortic curvature was compared between the pre- and post-operative CTAs to evaluate conformability of the CEXC. RESULTS: There were 87 patients with a 30 day CTA, and for 56 of these patients the one year CTA was available. Median (interquartile range [IQR]) pre-operative neck length was 22 mm (IQR 15, 32) and infrarenal angulation was 52° (IQR 31, 72). Median SAL was 21.2 mm (IQR 14.0, 29.3) at 30 days for all included patients. The SAL in 13 patients (15%) was < 10 mm at 30 days, and one patient had a SAL of 0 mm and a type Ia endoleak. There was no significant difference in SAL between patients within and outside instructions for use. The SAL significantly increased by 1.1 mm (IQR -2.3, 4.7; p = .042) at one year. The SAL decreased in seven patients (13%), increased in 13 patients (23%), and remained stable in 36 patients (64%). Median SFD was 2.0 mm (IQR 0.5, 3.6) at 30 days, which slightly increased by 0.3 mm (IQR -0.5, 1.8; p = .019) at one year. One patient showed migration (SFD increase ≥ 5 mm). Median endograft tilt was 15.8° (IQR 9.7, 21.4). Pre-operative maximum infrarenal curvature was 36 m-1 (IQR 26, 56) and did not significantly change thereafter. CONCLUSION: In most patients, the CEXC was implanted close to the renal arteries, and sufficient (≥ 10 mm) post-operative apposition was achieved at 30 days, which slightly increased at one year. Post-operative endograft tilt was relatively low, and aortic geometry remained unchanged after implantation of the CEXC, probably due to its high conformability.

Health Literacy and Disease Knowledge of Patients With Peripheral Arterial Disease or Abdominal Aortic Aneurysm: A Scoping Review.

OBJECTIVE: This scoping review summarises health literacy and disease knowledge in patients with abdominal aortic aneurysm (AAA) or peripheral arterial disease (PAD) and the influencing factors. DATA SOURCES: A systematic search was conducted in PubMed, Embase, PsychINFO, and CINAHL covering the period January 2012 to October 2022. REVIEW METHODS: This scoping review was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Inclusion criteria encompassed studies addressing health literacy, knowledge, perception, or awareness in patients with AAA or PAD. Two authors independently reviewed abstracts and full texts, resolving any discrepancies through discussion or by consulting a third author for consensus. All article types were included except letters, editorials, study protocols, reviews, and guidelines. No language restrictions were applied. Primary outcomes were health literacy and disease knowledge. Secondary outcomes were factors that could influence this. Quality assessment was done using the Mixed Methods Appraisal Tool (MMAT). RESULTS: The review included 32 articles involving a total of 5 268 patients. Four articles reported health literacy and the rest disease knowledge. Ten studies (31%) met all quality criteria. Twenty studies were quantitative, eight were qualitative, and four were mixed methods studies. The review revealed inadequate health literacy in the majority of patients, and disease knowledge was relatively low among patients with AAA and PAD, with disparities in measures and assessment tools across studies. Factors influencing health literacy and disease knowledge included socioeconomic status, education, income, and employment. CONCLUSION: This scoping review revealed low health literacy and low disease knowledge in patients with AAA and PAD. Standardised health literacy assessment may contribute to improve communication strategies and decision aids to enhance patients' understanding and engagement in healthcare decisions, however further research is needed to prove its merits.

Validity and Reliability of Wearable Sensors for Continuous Postoperative Vital Signs Monitoring in Patients Recovering from Trauma Surgery.

(1) Background: Wearable sensors support healthcare professionals in clinical decision-making by measuring vital parameters such as heart rate (HR), respiration rate (RR), and blood oxygenation saturation (SpO2). This study assessed the validity and reliability of two types of wearable sensors, based on electrocardiogram or photoplethysmography, compared with continuous monitoring of patients recovering from trauma surgery at the postanesthesia care unit. (2) Methods: In a prospective observational study, HR, RR, SpO2, and temperature of patients were simultaneously recorded with the VitalPatch and Radius PPG and compared with reference monitoring. Outcome measures were formulated as correlation coefficient for validity and mean difference with 95% limits of agreement for reliability for four random data pairs and 30-min pairs per vital sign per patient. (3) Results: Included were 60 patients. Correlation coefficients for VitalPatch were 0.57 to 0.85 for HR and 0.08 to 0.16 for RR, and for Radius PPG, correlation coefficients were 0.60 to 0.83 for HR, 0.20 to 0.12 for RR, and 0.57 to 0.61 for SpO2. Both sensors presented mean differences within the cutoff values of acceptable difference. (4) Conclusions: Moderate to strong correlations for HR and SpO2 were demonstrated. Although mean differences were within acceptable cutoff values for all vital signs, only limits of agreement for HR measured by electrocardiography were considered clinically acceptable.

Validation of an ex vivo Flow Model Including Magnetic Resonance Imaging to Study the Effects of Endovascular Treatments on the Arterial Wall.

Endovascular revascularization is the preferred treatment for peripheral arterial disease. Restenosis often occurs as a response to procedure-induced arterial damage. Reducing vascular injury during endovascular revascularization may improve its success rate. This study developed and validated an ex vivo flow model using porcine iliac arteries, obtained from a local abattoir. Twenty arteries (of 10 pigs) were equally allocated to two groups: a mock-treated control group and an endovascular intervention group. Arteries of both groups were perfused with porcine blood for 9 min, including 3 min of balloon angioplasty in the intervention group. Vessel injury was assessed by calculating the presence of endothelial cell denudation, vasomotor function, and histopathological analysis. MR imaging displayed balloon positioning and inflation. Endothelial cell staining showed 76% of denudation after ballooning compared to 6% in the control group (p < 0.001). This was confirmed by histopathological analysis, showing a significantly reduced endothelial nuclei count after ballooning compared to the controls (median: 22 vs. 37 nuclei/mm, p = 0.022). In the intervention group, vasoconstriction and endothelium-dependent relaxation were significantly reduced (p < 0.05).We present an ex vivo flow model to test the effects of endovascular therapy on the vessel's wall morphology, endothelial denudation, and endothelial-dependent vasomotor function under physiological conditions. Additionally, it allows the future testing of human arterial tissue.

Carotid calcium burden derived from computed tomography angiography as a predictor of all-cause mortality after carotid endarterectomy.

OBJECTIVE: Carotid endarterectomy (CEA) aims to reduce the risk of stroke in patients with atherosclerotic carotid disease. Preoperative risk assessments that predict complications are needed to optimize the care in this patient group. The current approach, namely relying solely on symptomatology and degree of stenosis, is outdated and calls for innovation. The Agatston calcium score was applied in several vascular specialties to assess cardiovascular risk profile but has been little studied in carotid surgery. It is hypothesized that a higher calcium burden at initial presentation equates to a worse prognosis attributable to an increased cerebrovascular and cardiovascular risk profile. The aim was to investigate the association between preoperative ipsilateral calcium score and postoperative all-cause mortality in patients undergoing CEA. METHODS: This single-center retrospective cohort study included 89 patients who underwent CEA at a tertiary referral center between 2010 and 2018. Preoperative calcium scores were measured on contrast-enhanced computed tomography images with patient-specific Hounsfield thresholds at the level of the carotid bifurcation. The association between these calcium scores and all-cause mortality was analyzed using multivariable adjusted Cox proportional hazard analysis. RESULTS: Cox proportional hazard analysis demonstrated a significant association between preoperative ipsilateral carotid calcium score and all-cause mortality (hazard ratio, 1.10; 95% confidence interval, 1.03-1.16; P = .003). After adjusting for age, preoperative estimated glomerular filtration rate, and diabetes mellitus, a significant association remained (hazard ratio, 1.07; 95% confidence interval, 1.00-1.15; P = .05). CONCLUSIONS: A higher calcium burden was predictive of worse outcome, which might be explained by an overall poorer health status. These results highlight the potential of calcium measurements in combination with other traditional risk factors, for preoperative risk assessment and thus for improved patient education and care.

In Vitro Geometry Analysis of Fenestrations in Endovascular Aneurysm Repair.

PURPOSE: Changes in the flared end of balloon-expandable covered stent (BECS) may precede BECS-associated complications but are not regularly assessed with computed tomographic angiography (CTA) after fenestrated endovascular aneurysm repair (FEVAR). Validation of the flare geometric analysis (FGA) and assessment of intraobserver and interobserver variability are investigated in this study. METHODS: Two series of 3 BeGraft BECSs (Bentley InnoMed GmbH, Hechingen, Germany) and 1 series of 3 Advanta V12 BECSs (Getinge AB, Göteborg, Sweden) were deployed in 3 side branches (45°, 60°, and 90° aortic branch angles) of an aorta phantom model. A standard post-FEVAR CTA scan was acquired. Computed tomographic angiography-derived measurements consisted of centerline reconstructions and placement of 3-dimensional coordinate markers by 2 observers in a vascular workstation. Flare geometric analysis calculates 3 BECS parameters: the circumferential flare-to-fenestration distance (FFD), which is the distance from the proximal end of the flare to fenestration, and diameters at the proximal end of the flare (Dflare) and at the fenestration (Dfenestration). Computed tomographic angiography-derived measurements were validated against microscopy measurements. Bland-Altman plots were used to determine the intraobserver and interobserver variability of the BECS parameters and intraclass correlation coefficient (ICC). RESULTS: For each BECS, the FFD at 4 equidistant quadrants of the circumference, Dflare, and Dfenestration were calculated. The mean difference and repeatability coefficient (RC) of the validation were 0.8 (2.1) mm for FFD, 0.4 (1.0) mm for Dflare, and -0.2 (1.2) mm for Dfenestration. The mean intraobserver and interobserver difference (RC) was 0.5 (1.6) mm and 0.7 (2.6) mm for FFD, 0.1 (0.6) mm and 0.1 (0.7) mm for Dflare, and -0.1 (0.8) mm and -0.8 (1.0) mm for Dfenestration. The mean ICC of intraobserver variability was 0.86 for FFD, 0.94 for Dflare, and 0.78 for Dfenestration. The mean ICC of interobserver variability was 0.77 for FFD, 0.92 for Dflare, and 0.48 for Dfenestration. CONCLUSION: This study showed that FGA of the flared ends of BECS can be performed with high accuracy in a phantom model, with good intraobserver and interobserver variability. Flare geometric analysis can be used to determine flare geometry of the BECS on standard post-FEVAR CTA scans.

Detecting Changes in Tissue Perfusion With Hyperspectral Imaging and Thermal Imaging Following Endovascular Treatment for Peripheral Arterial Disease.

PURPOSE: Hyperspectral imaging (HSI) and thermal imaging allow contact-free tissue perfusion measurements and may help determine the effect of endovascular treatment (EVT) in patients with peripheral arterial disease. This study aimed to detect changes in perfusion with HSI and thermal imaging peri-procedurally and determine whether these changes can identify limbs that show clinical improvement after 6 weeks. METHODS: Patients with Rutherford class 2-6 scheduled for EVT were included prospectively. Hyperspectral imaging and thermal imaging were performed directly before and after EVT. Images were taken from the lateral side of the calves and plantar side of the feet. Concentrations of (de)oxyhemoglobin, oxygen saturation, and skin temperature were recorded. Angiographic results were determined on completion angiogram. Clinical improvement 6 weeks after EVT was defined as a decrease ≥ one Rutherford class. Peri-procedural changes in perfusion parameters were compared between limbs with and without good angiographic results or clinical improvement. To identify limbs with clinical improvement, receiver operating characteristic (ROC) curves were used to determine cutoff values for change in HSI. RESULTS: Included were 23 patients with 29 treated limbs. Change in HSI values and temperature was not significantly different between limbs with good and poor angiographic results. Change in peri-procedural deoxyhemoglobin, determined by HSI, at the calves and feet was significantly different between limbs with and without clinical improvement at 6 week follow-up (p=0.027 and p=0.017, respectively). The ROC curve for change in deoxyhemoglobin at the calves showed a cutoff value of ≤1.0, and ≤-0.5 at the feet, which were discriminative for clinical improvement (sensitivity 77%; specificity 75% and sensitivity 62%; specificity 88%, respectively). CONCLUSIONS: HSI can detect changes in perfusion at the calves after EVT in patients with Rutherford class 2-6. Peri-procedural deoxyhemoglobin changes at the calves and feet are significantly different between limbs with and without clinical improvement. Decrease in deoxyhemoglobin directly after EVT may identify limbs that show clinical improvement 6 weeks after EVT.

A Statistical Shape Model of Infrarenal Aortic Necks in Patients With and Without Late Type Ia Endoleak After Endovascular Aneurysm Repair.

PURPOSE: Hostile aortic neck characteristics, including short length, severe suprarenal and infrarenal angulation, conicity, and large diameter, have been associated with increased risk for type Ia endoleak (T1aEL) after endovascular aneurysm repair (EVAR). This study investigates the mid-term discriminative ability of a statistical shape model (SSM) of the infrarenal aortic neck morphology compared with or in combination with conventional measurements in patients who developed T1aEL post-EVAR. MATERIALS AND METHODS: The dataset composed of EVAR patients who developed a T1aEL during follow-up and a control group without T1aEL. Principal component (PC) analysis was performed using a parametrization to create an SSM. Three logistic regression models were created. To discriminate between patients with and without T1aEL, sensitivity, specificity, and the area under the receiver operating characteristic (ROC) curve (AUC) were calculated. RESULTS: In total, 126 patients (84% male) were included. Median follow-up time in T1aEl group and control group was 52 (31, 78.5) and 51 (40, 62.5) months, respectively. Median follow-up time was not statistically different between the groups (p=0.72). A statistically significant difference between the median PC scores of the T1aEL and control groups was found for the first, eighth, and ninth PC. Sensitivity, specificity, and AUC values for the SSM-based versus the conventional measurements-based logistic regression models were 79%, 70%, and 0.82 versus 74%, 73%, and 0.85, respectively. The model of the SSM and conventional measurements combined resulted in sensitivity, specificity, and AUC of 81%, 81%, and 0.92. CONCLUSION: An SSM of the infrarenal aortic neck determines its 3-dimensional geometry. The SSM is a potential valuable tool for risk stratification and T1aEL prediction in EVAR. The SSM complements the conventional measurements of the individual preoperative infrarenal aortic neck geometry by increasing the predictive value for late type Ia endoleak after standard EVAR. CLINICAL IMPACT: A statistical shape model (SSM) determines the 3-dimensional geometry of the infrarenal aortic neck. The SSM complements the conventional measurements of the individual pre-operative infrarenal aortic neck geometry by increasing the predictive value for late type Ia endoleaks post-EVAR. The SSM is a potential valuable tool for risk stratification and late T1aEL prediction in EVAR and it is a first step toward implementation of a treatment planning support tool in daily clinical practice.

Implementing Wearable Sensors for Clinical Application at a Surgical Ward: Points to Consider before Starting.

Incorporating technology into healthcare processes is necessary to ensure the availability of high-quality care in the future. Wearable sensors are an example of such technology that could decrease workload, enable early detection of patient deterioration, and support clinical decision making by healthcare professionals. These sensors unlock continuous monitoring of vital signs, such as heart rate, respiration rate, blood oxygen saturation, temperature, and physical activity. However, broad and successful application of wearable sensors on the surgical ward is currently lacking. This may be related to the complexity, especially when it comes to replacing manual measurements by healthcare professionals. This report provides practical guidance to support peers before starting with the clinical application of wearable sensors in the surgical ward. For this purpose, the Non-Adoption, Abandonment, Scale-up, Spread, and Sustainability (NASSS) framework of technology adoption and innovations in healthcare organizations is used, combining existing literature and our own experience in this field over the past years. Specifically, the relevant topics are discussed per domain, and key lessons are subsequently summarized.

Shortest Apposition Length at the First Postoperative Computed Tomography Angiography Identifies Patients at Risk for Developing a Late Type Ia Endoleak After Endovascular Aneurysm Repair.

PURPOSE: Imaging surveillance following endovascular aneurysm repair (EVAR) is strictly recommended. This study investigates the value of endograft apposition and position relative to the aortic neck on the first postoperative computed tomography angiography (CTA) in determining patients at risk for a late type Ia endoleak (T1aEL). MATERIALS AND METHODS: Patients with a T1aEL after the first postoperative CTA were selected from a consecutive database and matched with uncomplicated controls. Endograft apposition and position, including the shortest apposition length (SAL), were determined on the first postoperative CTA. The SAL is the shortest distance between the proximal endograft fabric and the first slice where circumferential apposition with the aortic wall is lost. Differences in endograft apposition at the first postoperative CTA were compared between groups. Logistic regression analysis identified independent predictors for late T1aEL. RESULTS: A total of 32 patients with a late T1aEL were included and matched with 32 uncomplicated controls. Median follow-up after primary EVAR was 62.0 (interquartile range [IQR]: 36.8, 83.5) months in the T1aEL group compared with 47.5 (IQR: 34.0, 79.3) months in the control group; p=0.265. Median preoperative neck diameter was significantly larger in the T1aEL group than in the control group (26.6 [IQR: 24.9, 29.6] mm versus 23.4 [IQR: 22.5, 25.3] mm); p<0.001. Patients in the T1aEL group had a median SAL of 11.6 (IQR: 4.3, 20.5) mm compared with 20.7 (IQR: 13.1, 24.9) mm in the control group; p=0.002. SAL <10mm on the first postoperative CTA (odds ratio [OR]: 9.63, 95% confidence interval [CI]: 1.60-57.99) and larger neck diameter (OR: 1.80, 95% CI: 1.26-2.57) were independent predictors for developing a late T1aEL. CONCLUSION: Preoperative neck diameter and SAL on the first postoperative CTA following EVAR are important predictors for the development of a late T1aEL. Patients with a SAL of <10mm had a significantly higher risk of developing a late T1aEL. Future research should determine whether these patients would benefit from reintervention before an actual T1aEL is present. CLINICAL IMPACT: Understanding the mechanisms of endovascular aneurysm repair failure is essential to further enhance clinical outcomes. Adequate proximal sealing is necessary to foster freedom from type 1a endoleak. This study demonstrates that the shortest apposition length (SAL) at the first postoperative computed tomography angiography (CTA) is able to identify patients at risk for a late type 1a endoleak. Especially patients with a SAL <10mm are at high risk. Currently, the guidelines advice repeated imaging with CTA in patients with a seal <10mm. Future research should determine whether these patients would benefit from re-intervention before an actual type 1a endoleak is present.

Pre-operative Aortic Neck Characteristics and Post-operative Sealing Zone as Predictors of Type 1a Endoleak and Migration After Endovascular Aneurysm Repair: A Systematic Review and Meta-Analysis.

OBJECTIVE: Establishing the predictive value of neck characteristics and real achieved sealing zone is essential to foster risk stratified procedure selection and imaging surveillance. This systematic review provides an overview of pre-operative aortic neck characteristics and post-operative real achieved sealing zone and their respective risk of type 1a endoleak and migration after endovascular aneurysm repair (EVAR). METHODS: In agreement with PRISMA guidelines, MEDLINE, Embase, and Cochrane CENTRAL were searched. Data on neck characteristics, sealing zone, and EVAR outcome were extracted. Meta-analyses were performed to investigate the effect of neck diameter, angulation, and shape on type 1a endoleak (total, early ≤ 90 days, and late > 90 days) and migration in patients who underwent EVAR. A qualitative summary was also provided. RESULTS: Thirty-three studies were included. Patients with a larger neck diameter had an increased risk of total type 1a endoleak (nine studies: OR 3.32, 95% CI 2.38 - 4.63), early type 1a endoleak (six studies: OR 2.64, 95% CI 1.27 - 5.48), late type 1a endoleak (six studies: OR 3.26, 95% CI 2.12 - 5.03), and migration (seven studies: OR 2.88, 95% CI 1.32 - 6.26). An angulated neck increased the risk of total type 1a endoleak (seven studies: OR 4.27, 95% CI 1.55 - 11.78) and late type 1a endoleak (seven studies: OR 5.56, 95% CI 2.19 - 14.13). Neck shape was not associated with type 1a endoleak. Neck length and real achieved sealing zone on post-EVAR computed tomography were identified as risk factors for type 1a endoleak and migration through qualitative summary. CONCLUSION: There seems to be some consistent evidence that aortic neck diameter, angulation, and length are associated with the development of type 1a endoleak or migration. Real achieved sealing zone might be an important addition during follow up. However, a small number of studies, with serious limitations, could be included, and there was considerable variability in reporting patients and outcomes. A proposal for standardisation of aortic and EVAR data in future studies is provided.

Reliability assessment of hyperspectral imaging with the HyperView™ system for lower extremity superficial tissue oxygenation in young healthy volunteers.

PURPOSE: Hyperspectral imaging (HSI) is a noninvasive spectroscopy technique for determining superficial tissue oxygenation. The HyperView™ system is a hand-held camera that enables perfusion image acquisition. The evaluation of superficial tissue oxygenation is warranted in the evaluation of patients with peripheral arterial disease. The aim was to determine the reliability of repeated HSI measurements. METHODS: In this prospective cohort study, HSI was performed on 50 healthy volunteers with a mean age of 26.4 ± 2.5 years, at the lower extremity. Two independent observers performed HSI during two subsequent measurement sessions. Short term test-retest reliability and intra- and inter-observer reliability were determined, and generalizability and decision studies were performed. Transcutaneous oxygen pressure (TcPO2) measurements were also performed. RESULTS: The short term test-retest reliability was good for the HSI values determined at the lower extremity, ranging from 0.72 to 0.90. Intra- and inter-observer reliability determined at different days were poor to moderate for both HSI (0.24 to 0.71 and 0.30 to 0.58, respectively) and TcPO2 (0.54 and 0.56, and 0.51 and 0.31, respectively). Reliability can be increased to >0.75 by averaging two measurements on different days. CONCLUSION: This study showed good short term test-retest reliability for HSI measurements, however low intra- and inter-observer reliability was observed for tissue oxygenation measurements with both HSI and TcPO2 performed at separate days in young healthy volunteers. Reliability of HSI can be improved when determined as a mean of two measurements taken on different days.

Outcomes of Advanta V12 Covered Stents After Fenestrated Endovascular Aneurysm Repair.

PURPOSE: Fenestrated endovascular aneurysm repair (FEVAR) is a well-established endovascular treatment option for pararenal abdominal aortic aneurysms in which balloon-expandable covered stents (BECS) are used to bridge the fenestration to the target vessels. This study presents midterm clinical outcomes and patency rates of the Advanta V12 BECS used as a bridging stent. METHODS: All patients treated with FEVAR with at least 1 Advanta V12 BECS were included from 2 large-volume vascular centers between January 2012 and December 2015. Primary endpoints were freedom from all-cause reintervention, and freedom from BECS-associated complications and reintervention. BECS-associated complications included significant stenosis, occlusion, type 3 endoleak, or stent fracture. Secondary endpoints included all-cause mortality in-hospital and during follow-up. RESULTS: This retrospective study included 194 FEVAR patients with a mean age of 72.2±8.0 years. A total of 457 visceral arteries were stented with an Advanta V12 BECS. Median (interquartile range) follow-up time was 24.6 (1.6, 49.9) months. The FEVAR procedure was technically successful in 93% of the patients. Five patients (3%) died in-hospital. Patient survival was 77% (95% CI 69% to 84%) at 3 years. Freedom from all-cause reintervention was 70% (95% CI 61% to 78%) at 3 years, and 33% of all-cause reinterventions were BECS associated. Complications were seen in 24 of 457 Advanta V12 BECSs: type 3 endoleak in 8 BECSs, significant stenosis in 4 BECSs, occlusion in 6 BECSs, and stent fractures in 3 BECSs. A combination of complications occurred in 3 BECSs: type 3 endoleak and stenosis, stent fracture and stenosis, and stent fracture and occlusion. The freedom from BECS-associated complications for Advanta V12 BECSs was 98% (95% CI 96% to 99%) at 1 year and 92% (95% CI 88% to 95%) at 3 years. The freedom from BECS-associated reinterventions was 98% (95% CI 95% to 100%) at 1 year and 94% (95% CI 91% to 97%) at 3 years. CONCLUSION: The Advanta V12 BECS used as bridging stent in FEVAR showed low complication and reintervention rates at 3 years. A substantial number of FEVAR patients required a reintervention, but most were not BECS related.

Remodeling of Abdominal Aortic Angulation and Curvature After Endovascular Aneurysm Repair in Patients With vs Without Late Type Ia Endoleak or Endograft Migration.

PURPOSE: To investigate aortic remodeling of the supra- and infrarenal aorta from preoperative to 1 month and midterm follow-up after endovascular aneurysm repair (EVAR) by analyzing changes in angulation and curvature in patients with vs without late type Ia endoleak or device migration. MATERIALS AND METHODS: From a multicenter database, 35 patients (mean age 76±5 years; 31 men) were identified with late (>1 year) type Ia endoleak or endograft migration (≥10 mm) and defined as the complication group. The control group consisted of 53 patients (mean age 75±7 years; 48 men) with >1-year computed tomography angiography (CTA) follow-up and no evidence of endoleaks. Suprarenal and infrarenal angles were measured on centerline reconstructions of the preoperative, 1-month, and midterm CTA scans. The value and location relative to baseline of maximum suprarenal and infrarenal curvature were determined semiautomatically using dedicated software. Changes were determined at 1 month compared with the preoperative CTA and at midterm compared with 1 month. RESULTS: Preoperative suprarenal angulation was significantly greater in the complication group compared to the controls (34°±18° vs 24°±17°, p=0.008). It decreased significantly at 1 month in the complication group (29°±16°, p=0.011) and at midterm follow-up in the controls (20°±19°, p<0.001). Preoperative infrarenal angulation was not significantly different (57°±15° vs 49°±24°, p=0.114). This measurement increased significantly through midterm follow-up in the complication group (63°±23°, p<0.001) but remained stable in the controls (46°±22°). Preoperative suprarenal curvature was not significantly different (38±22 m-1 vs 29±25 m-1, p=0.115). This variable increased significantly through midterm follow-up in the complication group (44±22 m-1) but remained constant in the controls (28±22 m-1). Preoperative infrarenal curvature was significantly greater in the complication group (77±29 m-1 vs 65±28 m-1, p=0.047) and decreased significantly in both groups during midterm follow-up (50±17 m-1 vs 41±19 m-1 p=0.033). The location of the maximum curvature with regard to baseline shifted significantly distally in the complication group (54±43 to 72±41 mm, p<0.001), while it remained stable in the controls (46±33 to 48±31 mm). CONCLUSION: At midterm follow-up, significant differences in supra- and infrarenal angulation and curvature were observed between patients with vs without type Ia endoleak or migration. The location of the maximum curvature shifted distally in patients with complications. The aortic morphology is more stable during midterm follow-up in the patients without endoleaks.

Assessment of changes in stent graft geometry after chimney endovascular aneurysm sealing.

BACKGROUND: Chimney endovascular aneurysm sealing (ch-EVAS) could potentially minimize gutter-associated endoleaks in patients with juxtarenal abdominal aortic aneurysms resulting from the use of the conformable endobags surrounding the chimney stent grafts (ch-SGs). The aim of the present study was to quantify the (non)apposition of the endobags in the proximal aortic neck, migration of the endograft stent frames, and changes in geometry of the ch-SGs during the follow-up period. METHODS: The prospective data from 20 patients undergoing elective ch-EVAS were retrospectively reviewed. The aortic anatomy was analyzed on preoperative and postoperative computed tomography scans. The (non)apposition of the endobags in the aortic neck, Nellix (Endologix, Irvine, Calif) stent frame migration, and chimney graft geometry and migration were assessed. RESULTS: The median preoperative infrarenal neck length was 4.0 mm (interquartile range [IQR], 0-6.0 mm). The median seal length in the juxtarenal aortic neck at the first follow-up was 23.0 mm (IQR 18.0-30.8 mm). Five type IA endoleaks were identified on postoperative imaging; one at 1 month and four newly diagnosed at 1 year. Of these five type IA endoleaks, two were type Is1 (not extending into the aneurysm sac) and did not need reintervention and other three were type Is2 (extending into the aneurysm sac). One of these patients died of malignancy before reintervention could be performed. Bilateral ch-SG occlusions in one patient were documented at the 1-month follow-up (patient needed hemodialysis) and two patients with a new single ch-SG occlusion were found at the 1-year follow-up. No reinterventions were performed for the ch-SG occlusions. An occluded Nellix stent frame in one patient was treated with femorofemoral crossover bypass. Kaplan-Meier estimate of reintervention-free survival was 85.0% after 1 year. Migration ≥5 mm of the proximal end of the Nellix stent frames was observed in 20.0% of the patients, but no reintervention was performed at the 1-year follow-up. Imaging showed 20.1% of the available sealing surface was not used, and the nonapposition surface increased to 30.6% of the preoperative aortic neck surface at 1 year. Median migration was 3.5 mm (IQR, 2.4-5.0 mm) and 3.1 mm (IQR, 2.0-4.8 mm) for the left and right proximal end of the Nellix stent frames, respectively, and was 3.0 mm (IQR, 2.2-4.8 mm) for the proximal end of the ch-SGs at 1 year of follow-up. CONCLUSIONS: Substantial distal migration of the Nellix endograft and positional changes of the ch-SGs in the juxtarenal aortic neck were observed at 1 year of follow-up, resulting in a 25.0% type IA endoleak rate, with three of these type IA endoleaks extending into the aneurysm sac. The reintervention-free survival rate was 85.0% at 1 year in this cohort of 20 patients. Careful follow-up after ch-EVAS is advised because changes are often subtle. The authors have stopped the ch-EVAS procedure so far. Long-term follow-up data on the stability of the Nellix endograft and the consequences of migration on ch-SGs is required before this technique should be used in clinical practice.

Changes in Apposition of Endograft Limbs in the Iliac Arteries After Endovascular Aneurysm Repair: Determination With New Computed Tomography-Applied Software.

Purpose: To validate new computed tomography (CT)-applied software used to determine endograft limb position and apposition after endovascular aneurysm repair (EVAR). Materials and Methods: Twelve EVAR patients (mean age 81±6 years; 10 men) with distal stent-graft extensions for 15 (3 bilateral) type Ib endoleaks during follow-up were selected based on the availability of the following CT studies: pre-EVAR, 1 month, and the penultimate scan prior to the scan disclosing the type Ib endoleak. Twelve patients (mean age 82±7 years; 11 men) without endoleak and a similar interval between the primary EVAR procedure and the penultimate CT scan of the endoleak group were selected as controls using measurements from both endograft limbs (n=21, 3 excluded). Prototype Vascular Imaging Analysis software was adapted to calculate 6 parameters for the distal apposition zone: fabric distance, shortest apposition length, endograft diameter, iliac seal surface (ISS), iliac endograft apposition surface (IEAS), and percentage of iliac surface coverage (IEAS/ISS × 100). Measurements were performed on the preoperative, first postoperative, and penultimate/matched follow-up CT scans. Interobserver variability was assessed with the intraclass correlation coefficient (ICC). Continuous data are presented as the median [interquartile range (IQR) Q1, Q3]. Results: CTA follow-up was not significantly different between the endoleak and control groups [30 months (IQR 18, 58) vs 36 months (IQR 21, 59), p=0.843]. Interobserver agreement was good to excellent for all parameters (ICC 0.879-0.985). Preoperative anatomy and endograft dimensions on the first follow-up CTA scan did not differ significantly between the groups. When the penultimate CTA scan was compared with the first postoperative CT scan, endograft dimensions had significantly changed in the endoleak group; importantly, apposition was significantly decreased, and fabric distance was significantly increased, indicating limb retraction. Differences in changes in endograft dimensions were significant between the groups. Conclusion: New CT-applied software was introduced to visualize apposition and position changes of endograft limbs during follow-up. The software demonstrated good-to-excellent interobserver agreement and enabled accurate analysis of post-EVAR endograft dimensions. Significant changes in apposition and position were observed with the software on the penultimate CT scan prior to diagnosis of type Ib endoleak.

A New Methodology to Determine Apposition, Dilatation, and Position of Endografts in the Descending Thoracic Aorta After Thoracic Endovascular Aortic Repair.

Purpose: To validate computed tomography angiography (CTA)-applied software to assess apposition, dilatation, and position of endografts in the proximal and distal landing zones after thoracic endovascular aortic repair (TEVAR) of thoracic aortic aneurysm. Materials and Methods: Twenty-two patients (median age 75.5 years; 11 men) with a degenerative descending thoracic aortic aneurysm treated with TEVAR with at least one postoperative CTA were selected from a single center's database. New CTA-applied software was used to determine the available apposition surface in the proximal and distal landing zones, apposition of the endograft fabric with the aortic wall, shortest apposition length, endograft inflow and outflow diameters, shortest distance between the left subclavian artery and the proximal endograft fabric, and shortest distance between the celiac trunk and the distal endograft fabric on each CTA. Interobserver variability for these parameters was assessed with the repeatability coefficient and the intraclass correlation coefficient. Results: Excellent interobserver agreement was found for all measurements. Interobserver variability of surface and shortest apposition length calculations was larger for the distal site compared with the proximal site, with a mean difference of 10% vs 2% of the mean available apposition surface, 12% vs 5% of the endograft apposition surface, and 16% vs 8% of the shortest apposition length, respectively. Inflow and outflow diameters of the endograft showed low variability, with a mean difference of 0.1 mm with 95% of the interobserver difference within 1.8 mm. Mean interobserver differences of the proximal and distal shortest fabric distances were 1.0 and 0.9 mm (both 2% of the mean lengths). Conclusion: Assessment of apposition, dilatation, and position of the proximal and distal parts of an endograft in the descending thoracic aorta is feasible after TEVAR with the new software. Interobserver agreement for all measured parameters was excellent for the proximal and distal landing zones. The new method allows detection of subtle changes during follow-up. However, a larger study is needed to quantify how parameters change over time in complicated and uncomplicated TEVAR cases and to define the real added value of the new methodology.