Development and Evaluation of the Delivery-Based HEALED Produce Rx Program for Uninsured Patients With Diabetes in Rural Eastern North Carolina.

Produce prescription (PRx) programs have emerged as a preventive treatment to subsidize the cost of fruits and vegetables for people with lower income and have shown promise in improving diet quality and diabetes-related health outcomes (eg, glycated hemoglobin A1c). Researchers from the Department of Nutrition Science at East Carolina University worked with the Wayne Action Teams for Community Health (WATCH) Clinic, a safety-net clinic in rural Eastern North Carolina, and a local research farm to develop a PRx program for rural patients with type 2 diabetes and no health insurance. Preliminary patient surveys identified high levels of interest in a PRx program and a desire for recipes to accompany the produce. Formative evaluation results via telephone interviews with eligible patients identified transportation barriers to participation and the desire for complementary nutrition education and culinary resources. These results led to a delivery-based PRx program implemented from June through November 2021. Patients received weekly home delivery of an average of 4.7 pounds of fruits and vegetables and complementary nutrition and health education materials and culinary resources (cookbook, recipes). The level of patient satisfaction with the program was high; the reported level of consumption of produce, including unfamiliar produce, was high; educational resources were associated with increased knowledge and motivation to make healthful lifestyle changes, and glycemic control significantly improved. Ensuring that patients have a voice in the design and implementation of PRx programs is crucial to success. Ongoing use of rigorous formative and process evaluations can ensure appropriateness, use, and a positive effect of PRx programs, and they are needed to establish best practices for implementation.

Low Shear Stress at Baseline Predicts Expansion and Aneurysm-Related Events in Patients With Abdominal Aortic Aneurysm.

BACKGROUND: Low shear stress has been implicated in abdominal aortic aneurysm (AAA) expansion and clinical events. We tested the hypothesis that low shear stress in AAA at baseline is a marker of expansion rate and future aneurysm-related events. METHODS: Patients were imaged with computed tomography angiography at baseline and followed up every 6 months >24 months with ultrasound measurements of maximum diameter. From baseline computed tomography angiography, we reconstructed 3-dimensional models for automated computational fluid dynamics simulations and computed luminal shear stress. The primary composite end point was aneurysm repair and/or rupture, and the secondary end point was aneurysm expansion rate. RESULTS: We included 295 patients with median AAA diameter of 49 mm (interquartile range, 43-54 mm) and median follow-up of 914 (interquartile range, 670-1112) days. There were 114 (39%) aneurysm-related events, with 13 AAA ruptures and 98 repairs (one rupture was repaired). Patients with low shear stress (<0.4 Pa) experienced a higher number of aneurysm-related events (44%) compared with medium (0.4-0.6 Pa; 27%) and high (>0.6 Pa; 29%) shear stress groups (P=0.010). This association was independent of known risk factors (adjusted hazard ratio, 1.72 [95% CI, 1.08-2.73]; P=0.023). Low shear stress was also independently associated with AAA expansion rate (ß=+0.28 mm/y [95% CI, 0.02-0.53]; P=0.037). CONCLUSIONS: We show for the first time that low shear stress (<0.4 Pa) at baseline is associated with both AAA expansion and future aneurysm-related events. Aneurysms within the lowest tertile of shear stress, versus those with higher shear stress, were more likely to rupture or reach thresholds for elective repair. Larger prospective validation trials are needed to confirm these findings and translate them into clinical management.

Vascular surgery trainee retention in the UK: how many leave and why? A survey of trainee and Training Programme Directors' perceptions.

BACKGROUND: It is currently not known how many trainees leave vascular surgery, and their reasons for doing so are unclear. This paper is the first to publish the number of UK trainees leaving the training programme and interrogates their reasons for doing so. METHODS: An email survey was distributed to current and recent Training Programme Directors (TPDs) to quantify the number of trainees resigning between 2013 and 2019. Trainees resigning a National Training Number (NTN) were surveyed regarding their reasons for doing so. RESULTS: Since 2013, 23 UK vascular surgery trainees have resigned NTNs, representing 15.4% of the 149 NTNs awarded between 2013 and our analysis. Reasons for leaving, as relayed by TPDs, included availability of an academic career, geography, health and many other reasons classified as "work-life balance" factors. Data from the trainees surveyed also highlighted work-life balance but also identified pressures within the training system and NHS. CONCLUSIONS: UK data of this sort has not previously been available. The authors' primary recommendation is that prospective data collection on trainee retention is carried out, with structured exit interviews with trainees who decide to leave. Our secondary recommendations include improvements to the inter-deanery transfer process and early realistic exposure to vascular surgery for junior doctors to improve trainee retention rates in vascular surgery.

Development of a hidradenitis suppurativa patient decision aid.

BACKGROUND: Patient decision aids (PDAs) are tools that facilitate informed shared decision-making between patients and health care providers. To address a previously identified need in treatment decision-making in hidradenitis suppurativa (HS), we developed an HS-PDA. METHODS: Development of the HS-PDA was based on International Patient Decision Aids Standards. Evidence was derived from the North American Clinical Management Guidelines for HS. RESULTS: Content from guidelines was transformed into patient-friendly language and reviewed by three physicians and two patient representatives. Feedback on HS-PDA content, presentation and practicality was obtained from 7 HS patients and 5 physicians. Revisions were made following thematic analysis. All patients felt the content on treatment options contained the right amount of information and 5 found it helpful to see these options contextualized to their values. Each stated they would use the HS-PDA during treatment decision-making. Three and four physicians respectively indicated the content was accurate and language was patient-friendly. LIMITATIONS: Small sample sizes may limit generalizability. CONCLUSION: This HS-PDA was developed in accordance with international standards based on current HS guidelines with input from patients and physicians. It is available online without cost.

Reducing the risk of venous thromboembolism following superficial endovenous treatment: A UK and Republic of Ireland consensus study.

OBJECTIVES: Venous thromboembolism is a potentially fatal complication of superficial endovenous treatment. Proper risk assessment and thromboprophylaxis could mitigate this hazard; however, there are currently no evidence-based or consensus guidelines. This study surveyed UK and Republic of Ireland vascular consultants to determine areas of consensus. METHODS: A 32-item survey was sent to vascular consultants via the Vascular and Endovascular Research Network (phase 1). These results generated 10 consensus statements which were redistributed (phase 2). 'Good' and 'very good' consensus were defined as endorsement/rejection of statements by >67% and >85% of respondents, respectively. RESULTS: Forty-two consultants completed phase 1. This generated seven statements regarding risk factors mandating peri-procedural pharmacoprophylaxis and three statements regarding specific pharmacoprophylaxis regimes. Forty-seven consultants completed phase 2. Regarding venous thromboembolism risk factors mandating pharmacoprophylaxis, 'good' and 'very good' consensus was achieved for 5/7 and 2/7 statements, respectively. Regarding specific regimens, 'very good' consensus was achieved for 3/3 statements. CONCLUSIONS: The main findings from this study were that there was 'good' or 'very good' consensus that patients with any of the seven surveyed risk factors should be given pharmacoprophylaxis with low-molecular-weight heparin. High-risk patients should receive one to two weeks of pharmacoprophylaxis rather than a single dose.

Biomechanical Assessment Predicts Aneurysm Related Events in Patients with Abdominal Aortic Aneurysm.

OBJECTIVE: To test whether aneurysm biomechanical ratio (ABR; a dimensionless ratio of wall stress and wall strength) can predict aneurysm related events. METHODS: In a prospective multicentre clinical study of 295 patients with an abdominal aortic aneurysm (AAA; diameter ≥ 40 mm), three dimensional reconstruction and computational biomechanical analyses were used to compute ABR at baseline. Participants were followed for at least two years and the primary end point was the composite of aneurysm rupture or repair. RESULTS: The majority were male (87%), current or former smokers (86%), most (72%) had hypertension (mean ± standard deviation [SD] systolic blood pressure 140 ± 22 mmHg), and mean ± SD baseline diameter was 49.0 ± 6.9 mm. Mean ± SD ABR was 0.49 ± 0.27. Participants were followed up for a mean ± SD of 848 ± 379 days and rupture (n = 13) or repair (n = 102) occurred in 115 (39%) cases. The number of repairs increased across tertiles of ABR: low (n = 24), medium (n = 34), and high ABR (n = 44) (p = .010). Rupture or repair occurred more frequently in those with higher ABR (log rank p = .009) and ABR was independently predictive of this outcome after adjusting for diameter and other clinical risk factors, including sex and smoking (hazard ratio 1.41; 95% confidence interval 1.09-1.83 [p = .010]). CONCLUSION: It has been shown that biomechanical ABR is a strong independent predictor of AAA rupture or repair in a model incorporating known risk factors, including diameter. Determining ABR at baseline could help guide the management of patients with AAA.

Greater aortic inflammation and calcification in abdominal aortic aneurysmal disease than atherosclerosis: a prospective matched cohort study.

Objective: Using combined positron emission tomography and CT (PET-CT), we measured aortic inflammation and calcification in patients with abdominal aortic aneurysms (AAA), and compared them with matched controls with atherosclerosis. Methods: We prospectively recruited 63 patients (mean age 76.1±6.8 years) with asymptomatic aneurysm disease (mean size 4.33±0.73 cm) and 19 age-and-sex-matched patients with confirmed atherosclerosis but no aneurysm. Inflammation and calcification were assessed using combined 18F-FDG PET-CT and quantified using tissue-to-background ratios (TBRs) and Agatston scores. Results: In patients with AAA, 18F-FDG uptake was higher within the aneurysm than in other regions of the aorta (mean TBRmax2.23±0.46 vs 2.12±0.46, p=0.02). Compared with atherosclerotic control subjects, both aneurysmal and non-aneurysmal aortae showed higher 18F-FDG accumulation (total aorta mean TBRmax2.16±0.51 vs 1.70±0.22, p=0.001; AAA mean TBRmax2.23±0.45 vs 1.68±0.21, p<0.0001). Aneurysms containing intraluminal thrombus demonstrated lower 18F-FDG uptake within their walls than those without (mean TBRmax2.14±0.43 vs 2.43±0.45, p=0.018), with thrombus itself showing low tracer uptake (mean TBRmax thrombus 1.30±0.48 vs aneurysm wall 2.23±0.46, p<0.0001). Calcification in the aneurysmal segment was higher than both non-aneurysmal segments in patients with aneurysm (Agatston 4918 (2901-8008) vs 1017 (139-2226), p<0.0001) and equivalent regions in control patients (442 (304-920) vs 166 (80-374) Agatston units per cm, p=0.0042). Conclusions: The entire aorta is more inflamed in patients with aneurysm than in those with atherosclerosis, perhaps suggesting a generalised inflammatory aortopathy in patients with aneurysm. Calcification was prominent within the aneurysmal sac, with the remainder of the aorta being relatively spared. The presence of intraluminal thrombus, itself metabolically relatively inert, was associated with lower levels of inflammation in the adjacent aneurysmal wall.

Impact of a hidradenitis suppurativa patient decision aid on treatment decision making: A randomized controlled trial.

BACKGROUND: Patient decision aids are tools that facilitate shared decision making when clinical evidence and patient values and preferences inform the process. Evidence-based guidelines have been developed for clinicians in hidradenitis suppurativa management. To address treatment decision-making needs of hidradenitis suppurativa patients, we developed a hidradenitis suppurativa patient decision aid. OBJECTIVE: To assess the efficacy of the hidradenitis suppurativa patient decision aid during treatment decision making. METHODS: An online, participant-blinded, parallel-group, randomized controlled trial of the hidradenitis suppurativa patient decision aid versus Mayo Clinic hidradenitis suppurativa website content (Mayo) was conducted with hidradenitis suppurativa patients. Outcomes were knowledge, decisional conflict, and preparation for decision making. RESULTS: Forty participants fulfilled inclusion criteria and were randomized to hidradenitis suppurativa patient decision aid or Mayo. In the hidradenitis suppurativa patient decision aid group, data from 16 and 15 participants were analyzed at phases 1 and 2, respectively. In the Mayo group, data from 15 and 13 participants were analyzed at phases 1 and 2, respectively. Increased knowledge (P < .01) and preparation for decision making (P < .01), as well as reduced decisional conflict (P < .01), were observed in the hidradenitis suppurativa patient decision aid compared with the Mayo group. LIMITATIONS: The online methodology and recruitment from online hidradenitis suppurativa support groups limits generalizability of findings. CONCLUSION: A hidradenitis suppurativa patient decision aid increased knowledge and preparation for decision making and reduced decisional conflict.

Plasma Desmosine and Abdominal Aortic Aneurysm Disease.

Background It is recognized that factors beyond aortic size are important in predicting outcome in abdominal aortic aneurysm (AAA) disease. AAA is characterized by the breakdown of elastin within the aortic tunica media, leading to aortic dilatation and rupture. The aim of this study was to investigate the association of plasma desmosine (pDES), an elastin-specific degradation product, with disease severity and clinical outcome in patients with AAA. Methods and Results We measured pDES and serum biomarker concentrations in 507 patients with AAAs (94% men; mean age, 72.4±6.1 years; mean AAA diameter, 48±8 mm) and 162 control subjects (100% men; mean age, 71.5±4.4 years) from 2 observational cohort studies. In the longitudinal cohort study (n=239), we explored the incremental prognostic value of pDES on AAA events. pDES was higher in patients with AAA compared with control subjects (mean±SD: 0.46±0.22 versus 0.33±0.16 ng/mL; P<0.001) and had the strongest correlation with AAA diameter (r=0.39; P<0.0001) of any serum biomarker. After adjustment for baseline AAA diameter, pDES was associated with an AAA event (hazard ratio, 2.03 per SD increase [95% CI, 1.02-4.02]; P=0.044). In addition to AAA diameter, pDES provided incremental improvement in risk stratification (continuous net reclassification improvement, 34.4% [95% CI, -10.8% to 57.5%; P=0.09]; integrated discrimination improvement, 0.04 [95% CI, 0.00-0.15; P=0.050]). Conclusions pDES concentrations predict disease severity and clinical outcomes in patients with AAA. Clinical Trial Registration http://www.isrctn.com. Unique identifier: ISRCTN76413758.

Drug discontinuation before contrast procedures and the effect on acute kidney injury and other clinical outcomes: a systematic review protocol.

BACKGROUND: Contrast-induced acute kidney injury (CI-AKI) is defined as worsening of renal function after the administration of iodinated contrast material. In patients with cardiovascular disease, kidney disease, and/or diabetes, renin-angiotensin system blockers, non-steroidal anti-inflammatory drugs, diuretics, and metformin can increase the risk of CI-AKI when undergoing contrast imaging. Despite CI-AKI being the leading iatrogenic cause of acute kidney injury, there is a lack of sufficient scientific evidence supporting which drugs should be stopped, when they should be stopped, and when they should be resumed. The purpose of this systematic review is to assess (1) the effect of withholding medication before contrast procedures on the risk of CI-AKI and other clinical outcomes and (2) the incidence of adverse events occurring after withholding these drugs prior to contrast procedures. This protocol has been registered with PROSPERO, https://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42016033178 . METHODS: An information specialist will assist in searching MEDLINE, Embase, and the Cochrane Library databases to identify randomized controlled trials, observational studies, case reports, and case series. Relevant abstracts from professional society meetings and web-based registries of clinical trials will also be included. Studies included will compare patients aged ≥ 18 years instructed to continue taking the drugs of interest and those advised to stop taking them before undergoing contrast procedures. If these drugs are not withheld prior to contrast procedures, the studies must compare patients who are administered these drugs and those who are not before undergoing contrast procedures. Two reviewers will independently screen the titles and abstracts of the studies obtained from the search using pre-defined inclusion criteria and will then extract data from the full texts of selected studies. The quality of the studies will be assessed by two independent reviewers using the Cochrane Risk of Bias 2.0 tool for randomized trials and the Newcastle-Ottawa Scale for observational studies. DISCUSSION: This systematic review will provide a synthesis of current evidence on the discontinuation of drugs prior to contrast procedures and its effect on CI-AKI and other clinical outcomes. These findings will provide clinicians with guidelines and serve as a strong research base for future studies in this field. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42016033178.

18F-Sodium Fluoride Uptake in Abdominal Aortic Aneurysms: The SoFIA3 Study.

BACKGROUND: Fluorine-18-sodium fluoride (18F-NaF) uptake is a marker of active vascular calcification associated with high-risk atherosclerotic plaque. OBJECTIVES: In patients with abdominal aortic aneurysm (AAA), the authors assessed whether 18F-NaF positron emission tomography (PET) and computed tomography (CT) predicts AAA growth and clinical outcomes. METHODS: In prospective case-control (n = 20 per group) and longitudinal cohort (n = 72) studies, patients with AAA (aortic diameter >40 mm) and control subjects (aortic diameter <30 mm) underwent abdominal ultrasound, 18F-NaF PET-CT, CT angiography, and calcium scoring. Clinical endpoints were aneurysm expansion and the composite of AAA repair or rupture. RESULTS: Fluorine-18-NaF uptake was increased in AAA compared with nonaneurysmal regions within the same aorta (p = 0.004) and aortas of control subjects (p = 0.023). Histology and micro-PET-CT demonstrated that 18F-NaF uptake localized to areas of aneurysm disease and active calcification. In 72 patients within the longitudinal cohort study (mean age 73 ± 7 years, 85% men, baseline aneurysm diameter 48.8 ± 7.7 mm), there were 19 aneurysm repairs (26.4%) and 3 ruptures (4.2%) after 510 ± 196 days. Aneurysms in the highest tertile of 18F-NaF uptake expanded 2.5× more rapidly than those in the lowest tertile (3.10 [interquartile range (IQR): 2.34 to 5.92 mm/year] vs. 1.24 [IQR: 0.52 to 2.92 mm/year]; p = 0.008) and were nearly 3× as likely to experience AAA repair or rupture (15.3% vs. 5.6%; log-rank p = 0.043). CONCLUSIONS: Fluorine-18-NaF PET-CT is a novel and promising approach to the identification of disease activity in patients with AAA and is an additive predictor of aneurysm growth and future clinical events. (Sodium Fluoride Imaging of Abdominal Aortic Aneurysms [SoFIA3]; NCT02229006; Magnetic Resonance Imaging [MRI] for Abdominal Aortic Aneurysms to Predict Rupture or Surgery: The MA3RS Trial; ISRCTN76413758).

Exploring the Biological and Mechanical Properties of Abdominal Aortic Aneurysms Using USPIO MRI and Peak Tissue Stress: A Combined Clinical and Finite Element Study.

Inflammation detected through the uptake of ultrasmall superparamagnetic particles of iron oxide (USPIO) on magnetic resonance imaging (MRI) and finite element (FE) modelling of tissue stress both hold potential in the assessment of abdominal aortic aneurysm (AAA) rupture risk. This study aimed to examine the spatial relationship between these two biomarkers. Patients (n = 50) > 40 years with AAA maximum diameters > = 40 mm underwent USPIO-enhanced MRI and computed tomography angiogram (CTA). USPIO uptake was compared with wall stress predictions from CTA-based patient-specific FE models of each aneurysm. Elevated stress was commonly observed in areas vulnerable to rupture (e.g. posterior wall and shoulder). Only 16% of aneurysms exhibited co-localisation of elevated stress and mural USPIO enhancement. Globally, no correlation was observed between stress and other measures of USPIO uptake (i.e. mean or peak). It is suggested that cellular inflammation and stress may represent different but complimentary aspects of AAA disease progression.

Follow-up and surveillance of vein grafts: when and how to intervene to prevent complications.

Despite advances in endovascular strategies, surgical infrainguinal lower limb revascularization remains the gold standard treatment for critical lower limb ischemia and disabling claudication. Maintaining patency of infrainguinal vein bypass grafts has been a challenging task for vascular surgeons as they are prone to developing stenoses which may precipitate failure of the bypass. Duplex ultrasound scanning has evolved as the investigation of choice to identify vein graft lesions but graft surveillance programs using this technique remain controversial. The rationale for graft surveillance is that intervention in a patent but failing graft results in improved long-term patency and limb salvage rates compared to rescue of an occluded graft. The six-week postoperative Duplex ultrasound scan is important in identifying flow abnormalities that can predict the natural history of a vein graft and the outlook for the limb in the medium term. There are multiple factors influencing vein graft failure, which means guidelines should be flexible in terms of when and which type of intervention to the graft is optimum. Patency and durability favour open surgical revision over endovascular intervention but this must be counter balanced by the increased morbidity associated with surgical revision.

Validation of a Decision Tree to Streamline Infrainguinal Vein Graft Surveillance.

BACKGROUND: Duplex ultrasound (DU)-based graft surveillance remains controversial. The aim of this study was to assess the ability of a recently proposed decision tree in identifying high-risk grafts which would benefit from DU-based surveillance. MATERIALS AND METHODS: Consecutive patients undergoing infrainguinal vein graft bypass from January 2008 to December 2015 were identified from the National Vascular registry and enrolled in a duplex surveillance program. An early postoperative DU was performed at a median of 6 weeks (range: 4-9 weeks). Grafts were classified into high risk or low risk based on the findings of the earliest postoperative scan and 4 established risk factors for graft failure (diabetes, smoking, infragenicular distal anastomosis, and revision bypass surgery) using a classification and regression tree (CRT). The accuracy of the CRT model was evaluated using area under receiver operator characteristic (AROC) curve. RESULTS: About 278 vein graft bypasses were performed; 29 grafts had occluded by the first surveillance visit; 249 vein grafts were entered into surveillance. Sixty-four (23%) developed critical stenosis. Overall 30-month primary patency, primary-assisted patency, and secondary patency rates were 71.2%, 77.2%, and 80.1%, respectively. AROC for prediction of graft stenosis or occlusion was 83% (95% confidence interval [CI]: 78-87%). The sensitivity and specificity of the CRT model for prediction of graft stenosis or occlusion were 95% (95% CI: 88-98%) and 52.2% (95% CI: 45-60%). CONCLUSIONS: A prediction model based on commonly recorded clinical variables and early postoperative DU scan is accurate at identifying grafts which are at high risk of failure. These high-risk grafts may benefit from DU-based surveillance.

Pharmacomechanical thrombectomy for iliofemoral deep vein thrombosis.

BACKGROUND: Deep venous thrombosis (DVT) occurs in approximately one in 1000 adults every year, and has an annual mortality of 14.6%. In particular, iliofemoral DVT can lead to recurrent thrombosis and post-thrombotic syndrome (PTS), a painful condition which can lead to chronic venous insufficiency, oedema, and ulceration. It causes significant disability, impaired quality of life, and economic burden. Early thrombus removal techniques have been advocated in patients with an iliofemoral DVT in order to improve vein patency, prevent valvular dysfunction, and reduce future complications, such as post-thrombotic syndrome and venous ulceration. One such technique is pharmacomechanical thrombectomy, a combination of catheter-based thrombectomy and catheter-directed thrombolysis. OBJECTIVES: To assess the effects of pharmacomechanical thrombectomy versus anticoagulation (alone or with compression stockings), mechanical thrombectomy, thrombolysis, or other endovascular techniques in the management of people with acute DVT of the iliofemoral vein. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Specialised Register (last searched December 2015) and the Cochrane Register of Studies (last searched December 2015). We searched clinical trials databases for details of ongoing or unpublished studies and the reference lists of relevant articles retrieved by electronic searches for additional citations. SELECTION CRITERIA: Randomised controlled trials in which patients with an iliofemoral deep vein thrombosis were allocated to receive pharmacomechanical thrombectomy versus anticoagulation, mechanical thrombectomy, thrombolysis (systemic or catheter directed thrombolysis), or other endovascular techniques for the treatment of iliofemoral DVT. DATA COLLECTION AND ANALYSIS: At least two review authors independently assessed studies identified for potential inclusion. MAIN RESULTS: We found no randomised controlled trials that met the eligibility criteria for this review. We identified one ongoing study. AUTHORS' CONCLUSIONS: There were no randomised controlled trials that assessed the effects of pharmacomechanical thrombectomy versus anticoagulation (alone or with compression stockings), mechanical thrombectomy, thrombolysis, or other endovascular techniques in the management of people with acute DVT of the iliofemoral vein that met the eligibility criteria for this review. Further high quality randomised controlled trials are needed.

Development of a Decision Tree to Streamline Infrainguinal Vein Graft Surveillance.

BACKGROUND: Duplex ultrasound (DU) remains the gold standard for identification and grading of infrainguinal vein graft stenosis. However, DU-based graft surveillance remains controversial. The aim of this study was to develop a decision tree to identify high-risk grafts which would benefit from DU-based surveillance. METHODS: Consecutive patients undergoing infrainguinal vein graft bypass were enrolled in a DU surveillance program. An early postoperative DU was performed at a median of 6 weeks (range 4-9). Based on the findings of this scan and 4 established risk factors for graft failure (diabetes, smoking, infragenicular distal anastomosis, revision bypass surgery), a classification and regression tree (CART) was created to stratify grafts into grafts which are at high and low risk of developing severe stenosis or occlusion. The accuracy of the CART model was evaluated using area under receiver operator characteristic curve (ROC). RESULTS: Of 796 vein graft bypasses performed (760 patients), 64 grafts were occluded by the first surveillance visit and 732 vein grafts were entered into surveillance program. The CART model stratified 299 grafts (40.8%) as low-risk and 433 (59.2%) as high-risk grafts. One hundred twenty-six (17.2%) developed critical vein graft stenosis. Overall, 30-month primary patency, primary-assisted and secondary patency rates were 76.2%, 83.6%, and 85.3%, respectively. The area under ROC curve for the CART model was 0.88 (95% confidence interval 0.81-0.94). Primary graft patency rates were higher in low-risk versus high-risk grafts (log rank 186, P < 0.0001). Amputation rates were significantly higher in the high-risk grafts compared with low-risk ones (log rank 118, P < 0.0001). CONCLUSION: A clinical decision rule based on readily available clinical data and the findings of significant flow abnormalities on an early postoperative DU scan successfully identifies grafts at high risk of failure and will contribute to safely improving the efficacy of infrainguinal vein graft surveillance services.

Patient-specific modelling of abdominal aortic aneurysms: The influence of wall thickness on predicted clinical outcomes.

Rupture of abdominal aortic aneurysms (AAAs) is linked to aneurysm morphology. This study investigates the influence of patient-specific (PS) AAA wall thickness on predicted clinical outcomes. Eight patients under surveillance for AAAs were selected from the MA(3)RS clinical trial based on the complete absence of intraluminal thrombus. Two finite element (FE) models per patient were constructed; the first incorporated variable wall thickness from CT (PS_wall), and the second employed a 1.9mm uniform wall (Uni_wall). Mean PS wall thickness across all patients was 1.77±0.42mm. Peak wall stress (PWS) for PS_wall and Uni_wall models was 0.6761±0.3406N/mm(2) and 0.4905±0.0850N/mm(2), respectively. In 4 out of 8 patients the Uni_wall underestimated stress by as much as 55%; in the remaining cases it overestimated stress by up to 40%. Rupture risk more than doubled in 3 out of 8 patients when PS_wall was considered. Wall thickness influenced the location and magnitude of PWS as well as its correlation with curvature. Furthermore, the volume of the AAA under elevated stress increased significantly in AAAs with higher rupture risk indices. This highlights the sensitivity of standard rupture risk markers to the specific wall thickness strategy employed.

MRI using ultrasmall superparamagnetic particles of iron oxide in patients under surveillance for abdominal aortic aneurysms to predict rupture or surgical repair: MRI for abdominal aortic aneurysms to predict rupture or surgery-the MA(3)RS study.

INTRODUCTION: Population screening for abdominal aortic aneurysms (AAA) halves the associated mortality and has led to the establishment of national screening programmes. Prediction of aneurysm growth and rupture is challenging and currently relies on serial diameter measurements with ultrasound. Recently, a novel MRI-based technique using ultrasmall superparamagnetic particles of iron oxide (USPIO) has demonstrated considerable promise as a method of identifying aneurysm inflammation and expansion. METHODS AND ANALYSIS: The MA(3)RS study is a prospective observational multicentre cohort study of 350 patients with AAA in three centres across Scotland. All participants will undergo MRI with USPIO and aneurysm expansion will be measured over 2 years with CT in addition to standard clinical ultrasound surveillance. The relationship between mural USPIO uptake and subsequent clinical outcomes, including expansion, rupture and repair, will be evaluated and used to determine whether the technique augments standard risk prediction markers. To ensure adequate sensitivity to answer the primary question, we need to observe 130 events (composite of rupture or repair) with an estimated event rate of 41% over 2 years of follow-up. The MA(3)RS study is currently recruiting and expects to report in 2017. DISCUSSION: This is the first study to evaluate the use of USPIO-enhanced MRI to provide additional information to aid risk prediction models in patients with AAA. If successful, this study will lay the foundation for a large randomised controlled trial targeted at applying this technique to determine clinical management. TRIAL REGISTRATION NUMBER: Current Controlled Trials: ISRCTN76413758.