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Objectives This survey study evaluates current management strategies for venous ulceration and the impacts of the EVRA trial results. Methods An online survey was disseminated to approximately 15000 clinicians, through 12 vascular societies in 2018. Survey themes included: referral times, treatment times and strategies, knowledge of the EVRA trial and service barriers to managing venous ulceration. Data analysis was performed using Microsoft Excel and SPSS. Results 664 responses were received from 78 countries. Respondents were predominantly European (55%) and North American (23%) vascular surgeons (74%). Responses varied between different countries. The median vascular clinic referral time was 6 weeks and time to be seen in clinic was 2 weeks. This was significantly higher in the UK (p ≤ 0.02). 77% of respondents performed surgical/endovenous interventions prior to ulcer healing, the median time to intervention was 4 weeks. 31% of participants changed their practice following EVRA. Frequently encountered barriers to implementing change were a lack of operating space/time (18%). Conclusion Venous ulcers are not managed as quickly as they should be. An evaluation of local resource requirements should be performed to improve service provision for venous ulceration. When interpreting the results of this survey consideration should be given to the response rate.

Background Various guidelines exist worldwide for the diagnosis and management of venous leg ulcers; however, these are difficult to implement resulting in disparate treatment of patients globally. Method An online, 26-question survey was designed to evaluate the current global management of venous leg ulceration and was emailed globally to approximately 15,000 participants (November 2017–February 2018). Results Overall, 799 responses were received from 86 countries, with a 5% response rate. The respondent physicians saw a median of 10 (interquartile range 5–20) patients per month, with a median time to referral from primary to secondary care of six weeks. Of the respondents, 61% arranged an ankle brachial pressure index on first visit and 84% performed a venous duplex, with 95% prescribing compression for those in whom it was not contraindicated. Fifty-nine percent performed endovenous intervention or surgery prior to ulcer healing. Conclusions The survey showed a diversity of treatment pathways. The need to develop a robust, clear pathway for patients with leg ulceration is clearly required.

With inconsistent care pathways and variable referral policies, venous leg ulcer care is often suboptimal. Alun Davies, Jocelyn Mora, Manjit Gohel, Francine Heatley and Karen Dhillon discuss the benefits of early intervention

Venous leg ulcers can go unnoticed for some time, especially with people who receive care in the community. Alun Davies, Jocelyn Mora, Manjit Gohel, Francine Heatley and Karen Dhillon discuss the benefits of early intervention.

This study is supported by the J P Moulton Charitable Foundation (grant number: N/A). The DCD allograft is provided free of charge by NHSBT., The authors wish to thank the principal investigators, research nurses and their teams at the recruiting sites. The authors also wish to thank the NHS Blood and Transplant (NHSBT) for providing the DCD allograft free of charge and for their support in training clinical staff, and the NIHR Clinical Research Networks (CRNs) for their support in identifying sites. Finally, the authors wish to thank all individuals who participated in the PPI focus groups and extend a special thank you to PPI representative Emanuel Ezeife, whose useful feedback helped to inform the design of the study., Introduction Venous leg ulceration (VLU), the most common type of chronic ulcer, can be difficult to heal and is a major cause of morbidity and reduced quality of life. Although compression bandaging is the principal treatment, it is time-consuming and bandage application requires specific training. There is evidence that intervention on superficial venous incompetence can help ulcer healing and recurrence, but this is not accessible to all patients. Hence, new treatments are required to address these chronic wounds. One possible adjuvant treatment for VLU is human decellularised dermis (DCD), a type of skin graft derived from skin from deceased tissue donors. Although DCD has the potential to promote ulcer healing, there is a paucity of data for its use in patients with VLU. Methods and analysis This is a multicentre, parallel group, pragmatic randomised controlled trial. One hundred and ninety-six patients with VLU will be randomly assigned to receive either the DCD allograft in addition to standard care or standard care alone. The primary outcome is the proportion of participants with a healed index ulcer at 12 weeks post-randomisation in each treatment arm. Secondary outcomes include the time to index ulcer healing and the proportion of participants with a healed index ulcer at 12 months. Changes in quality of life scores and cost-effectiveness will also be assessed. All analyses will be carried out on an intention-to-treat (ITT) basis. A mixed-effects, logistic regression on the outcome of the proportion of those with the index ulcer healed at 12 weeks will be performed. Secondary outcomes will be assessed using various statistical models appropriate to the distribution and nature of these outcomes. Ethics and dissemination Ethical approval was granted by the Bloomsbury Research Ethics Committee (19/LO/1271). Findings will be published in a peer-reviewed journal and presented at national and international conferences., J P Moulton Charitable Foundation

Venous leg ulceration (VLU) is a public health concern that is largely managed in community settings. The present study aimed to survey current VLU management in the community. A 14-question survey was distributed to primary care professionals, and 90 responses were received. Some 54% of respondents stated that they would assess ankle brachial pressure indices (ABPI) for those with VLU, while 25% reported that they would not. Additionally, 62% reported not organising duplex ultrasound scanning. Compression therapy was offered by 82% of respondents. When asked whether VLU patients were referred to specialist services in secondary or tertiary care, some 32% reported that they would. However, 57% reported that, if a study suggested that referral to specialist services was beneficial, they would change their practice. On the basis of the findings, the authors concluded that there is diversity in VLU diagnostic and treatment pathways. New, high-quality evidence may improve practice, but care delivery is influenced by local factors including time and resource distribution.

Objective Determine standards of referral and management of patients with venous leg ulceration in primary care after the release of the EVRA (A Randomized Trial of Early Endovenous Ablation in Venous Ulceration) study results. Methods An online questionnaire was disseminated over four months to professionals working within primary care. Results The survey received 643 responses. Of respondents, 90 (14%) had heard of the EVRA trial and 51 (8%) were familiar with the results. Of those who answered the following questions, 410 (69.1%) stated that referral to a vascular specialist must be made by the General Practitioner and 13 (2.2%) reported that they would always refer patients for secondary care assessment before the publication of EVRA. Considering the EVRA results, 128 (29%) reported that they would change practice regarding referral and would experience no barriers and 198 (45%) reported that they would like to refer earlier but is not their decision. Barriers to changing practice included local referral policies, training and time restrictions, 266 (59%) had heard of the NICE guideline (CG168) and 194 (43%) were aware of the recommendations for referral to a vascular service within two weeks for patients with an open or healed ulcer. Conclusion There is a considerable variation in local referral pathways for venous leg ulceration, and despite clinicians wanting to refer promptly, many primary care professionals are unable to. Unfortunately, the EVRA study alone may not change the overall practice, and work is needed to overcome barriers faced by primary care professionals.

BACKGROUND: The evidence base upon which current global venous thromboembolism (VTE) prevention recommendations have been made is not optimal. The cost of purchasing and applying graduated compression stockings (GCS) in surgical patients is considerable and has been estimated at £63.1 million per year in England alone.OBJECTIVE: The aim was to determine whether low dose low molecular weight heparin (LMWH) alone is non-inferior to a combination of GCS and low dose LMWH for the prevention of VTE.METHODS: The randomised controlled Graduated compression as an Adjunct to Pharmacoprophylaxis in Surgery (GAPS) Trial (ISRCTN 13911492) will randomise adult elective surgical patients identified as being at moderate and high risk of VTE to receive either the current "standard" combined thromboprophylactic LMWH with GCS mechanical thromboprophylaxis, or thromboprophylactic LMWH pharmacoprophylaxis alone. To show non-inferiority (3.5% non-inferiority margin) for the primary endpoint of all VTE within 90 days, 2236 patients are required. Recruitment will be from seven UK centres. Secondary outcomes include quality of life, compliance with stockings and LMWH, overall mortality, and GCS or LMWH related complications (including bleeding). Recruitment commenced in April 2016 with the seven UK centres coming "on-line" in a staggered fashion. Recruitment will be over a total of 18 months. The GAPS trial is funded by the National Institute for Health Research Health Technology Assessment in the UK (14/140/61).

Background Treatment of superficial venous reflux in addition to compression therapy accelerates venous leg ulcer healing and reduces ulcer recurrence. The aim of this study was to evaluate the costs and cost-effectiveness of early versus delayed endovenous treatment of patients with venous leg ulcers. Methods This was a within-trial cost-utility analysis with a 1-year time horizon using data from the EVRA (Early Venous Reflux Ablation) trial. The study compared early versus deferred endovenous ablation for superficial venous truncal reflux in patients with a venous leg ulcer. The outcome measure was the cost per quality-adjusted life-year (QALY) over 1 year. Sensitivity analyses were conducted with alternative methods of handling missing data, alternative preference weights for health-related quality of life, and per protocol. Results After early intervention, the mean(s.e.m.) cost was higher (difference in cost per patient £163(318) (€184(358))) and early intervention was associated with more QALYs at 1 year (mean(s.e.m.) difference 0·041(0·017)). The incremental cost-effectiveness ratio (ICER) was £3976 (€4482) per QALY. There was an 89 per cent probability that early venous intervention is cost-effective at a threshold of £20 000 (€22 546)/QALY. Sensitivity analyses produced similar results, confirming that early treatment of superficial reflux is highly likely to be cost-effective. Conclusion Early treatment of superficial reflux is highly likely to be cost-effective in patients with venous leg ulcers over 1 year. Registration number: ISRCTN02335796 (http://www.isrctn.com).

This randomized clinical trial uses data from the Early Venous Reflux Ablation trial to evaluate the long-term clinical and cost benefits of combined early endovenous ablation and compression compared with compression therapy alone and deferred ablation for treating superficial venous reflux of the leg., Key Points Question In patients with venous leg ulceration and superficial reflux, what is the clinical and cost-effectiveness of early endovenous ablation of reflux? Findings In this 450-patient, multicenter, randomized clinical trial, early endovenous ablation with compression accelerated venous ulcer healing, reduced the overall incidence of ulcer recurrence, and was highly cost-effective compared with compression with deferred intervention. Meaning To deliver clinical and cost benefits, leg ulcer care pathways should be revised to include early assessment and treatment of superficial venous reflux., Importance One-year outcomes from the Early Venous Reflux Ablation (EVRA) randomized trial showed accelerated venous leg ulcer healing and greater ulcer-free time for participants who are treated with early endovenous ablation of lower extremity superficial reflux. Objective To evaluate the clinical and cost-effectiveness of early endovenous ablation of superficial venous reflux in patients with venous leg ulceration. Design, Setting, and Participants Between October 24, 2013, and September 27, 2016, the EVRA randomized clinical trial enrolled 450 participants (450 legs) with venous leg ulceration of less than 6 months’ duration and superficial venous reflux. Initially, 6555 patients were assessed for eligibility, and 6105 were excluded for reasons including ulcer duration greater than 6 months, healed ulcer by the time of randomization, deep venous occlusive disease, and insufficient superficial venous reflux to warrant ablation therapy, among others. A total of 426 of 450 participants (94.7%) from the vascular surgery departments of 20 hospitals in the United Kingdom were included in the analysis for ulcer recurrence. Surgeons, participants, and follow-up assessors were not blinded to the treatment group. Data were analyzed from August 11 to November 4, 2019. Interventions Patients were randomly assigned to receive compression therapy with early endovenous ablation within 2 weeks of randomization (early intervention, n = 224) or compression with deferred endovenous treatment of superficial venous reflux (deferred intervention, n = 226). Endovenous modality and strategy were left to the preference of the treating clinical team. Main Outcomes and Measures The primary outcome for the extended phase was time to first ulcer recurrence. Secondary outcomes included ulcer recurrence rate and cost-effectiveness. Results The early-intervention group consisted of 224 participants (mean [SD] age, 67.0 [15.5] years; 127 men [56.7%]; 206 White participants [92%]). The deferred-intervention group consisted of 226 participants (mean [SD] age, 68.9 [14.0] years; 120 men [53.1%]; 208 White participants [92%]). Of the 426 participants whose leg ulcer had healed, 121 (28.4%) experienced at least 1 recurrence during follow-up. There was no clear difference in time to first ulcer recurrence between the 2 groups (hazard ratio, 0.82; 95% CI, 0.57-1.17; P = .28). Ulcers recurred at a lower rate of 0.11 per person-year in the early-intervention group compared with 0.16 per person-year in the deferred-intervention group (incidence rate ratio, 0.658; 95% CI, 0.480-0.898; P = .003). Time to ulcer healing was shorter in the early-intervention group for primary ulcers (hazard ratio, 1.36; 95% CI, 1.12-1.64; P = .002). At 3 years, early intervention was 91.6% likely to be cost-effective at a willingness to pay of £20 000 ($26 283) per quality-adjusted life year and 90.8% likely at a threshold of £35 000 ($45 995) per quality-adjusted life year. Conclusions and Relevance Early endovenous ablation of superficial venous reflux was highly likely to be cost-effective over a 3-year horizon compared with deferred intervention. Early intervention accelerated the healing of venous leg ulcers and reduced the overall incidence of ulcer recurrence. Trial Registration ClinicalTrials.gov identifier: ISRCTN02335796

Background Venous ulceration is a common and costly health-care issue worldwide, with poor healing rates greatly affecting patient quality of life. Compression bandaging has been shown to improve healing rates and reduce recurrence, but does not address the underlying cause, which is often superficial venous reflux. Surgical correction of the reflux reduces ulcer recurrence; however, the effect of early endovenous ablation of superficial venous reflux on ulcer healing is unclear. Objectives To determine the clinical effectiveness and cost-effectiveness of compression therapy with early endovenous ablation of superficial venous reflux compared with compression therapy with deferred endovenous ablation in patients with venous ulceration. Design A pragmatic, two-arm, multicentre, parallel-group, open randomised controlled trial with a health economic evaluation. Setting Secondary care vascular centres in England. Participants Patients aged ≥ 18 years with a venous leg ulcer of between 6 weeks’ and 6 months’ duration and an ankle–brachial pressure index of ≥ 0.8 who could tolerate compression and were deemed suitable for endovenous ablation of superficial venous reflux. Interventions Participants were randomised 1 : 1 to either early ablation (compression therapy and superficial endovenous ablation within 2 weeks of randomisation) or deferred ablation (compression therapy followed by endovenous ablation once the ulcer had healed). Main outcome measures The primary outcome measure was time from randomisation to ulcer healing, confirmed by blinded assessment. Secondary outcomes included 24-week ulcer healing rates, ulcer-free time, clinical success (in addition to quality of life), costs and quality-adjusted life-years (QALYs). All analyses were performed on an intention-to-treat basis. Results A total of 450 participants were recruited (224 to early and 226 to deferred superficial endovenous ablation). Baseline characteristics were similar between the two groups. Time to ulcer healing was shorter in participants randomised to early superficial endovenous ablation than in those randomised to deferred ablation [hazard ratio 1.38, 95% confidence interval (CI) 1.13 to 1.68; p = 0.001]. Median time to ulcer healing was 56 (95% CI 49 to 66) days in the early ablation group and 82 (95% CI 69 to 92) days in the deferred ablation group. The ulcer healing rate at 24 weeks was 85.6% in the early ablation group, compared with 76.3% in the deferred ablation group. Median ulcer-free time was 306 [interquartile range (IQR) 240–328] days in the early ablation group and 278 (IQR 175–324) days in the deferred endovenous ablation group (p = 0.002). The most common complications of superficial endovenous ablation were pain and deep-vein thrombosis. Differences in repeated measures of Aberdeen Varicose Vein Questionnaire scores (p p = 0.03) and Short Form questionnaire-36 items body pain (p = 0.05) over the follow-up period were observed, in favour of early ablation. The mean difference in total costs between the early ablation and deferred ablation groups was £163 [standard error (SE) £318; p = 0.607]; however, there was a substantial and statistically significant gain in QALY over 1 year [mean difference between groups 0.041 (SE 0.017) QALYs; p = 0.017]. The incremental cost-effectiveness ratio of early ablation at 1 year was £3976 per QALY, with a high probability (89%) of being more cost-effective than deferred ablation at conventional UK decision-making thresholds (currently £20,000 per QALY). Sensitivity analyses using alternative statistical models give qualitatively similar results. Limitations Only 7% of screened patients were recruited, treatment regimens varied significantly and technical success was assessed only in the early ablation group. Conclusions Early endovenous ablation of superficial venous reflux, in addition to compression therapy and wound dressings, reduces the time to healing of venous leg ulcers, increases ulcer-free time and is highly likely to be cost-effective. Future work Longer-term follow-up is ongoing and will determine if early ablation will affect recurrence rates in the medium and long term. Trial registration Current Controlled Trials ISRCTN02335796. Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 24. See the NIHR Journals Library website for further project information.

Objective To assess the clinical efficacy of a neuromuscular electrical stimulation (NMES) device to improve the absolute walking distance in patients with intermittent claudication as an adjunct to the local standard care available at the study sites compared with local standard care alone. Methods This open, multicenter, randomized controlled trial included eight participating centers in England. Sites are equally distributed between those that provide supervised exercise therapy programs and those that do not. Patients with intermittent claudication meeting the eligibility criteria and providing consent will be randomized, depending on the center type, to either NMES and locally available standard care or standard care alone. The primary end point is change in absolute walking distance at 3 months (the end of the intervention period) by treadmill testing. Secondary outcomes include quality of life, compliance with the interventions, economic evaluation of the NMES device, and lower limb hemodynamic measures to further the understanding of underlying mechanisms. Recruitment commenced in March 2018 and will continue for a total of 15 months. The Neuromuscular Electrical Stimulation Improves the Absolute Walking Distance in Patients with Intermittent Claudication trial is funded by the UK Efficacy and Mechanism Evaluation Programme, Medical Research Council, and National Institute for Health Research partnership.

Background Venous leg ulcers impair quality of life significantly, with substantial costs to health services. The aim of this study was to estimate the cost-effectiveness of interventional procedures alongside compression therapy versus compression therapy alone for the treatment of chronic venous leg ulceration. Methods A Markov decision analytical model was developed. The main outcome measures were quality-adjusted life-years (QALYs) and lifetime costs per patient, from the perspective of the UK National Health Service at 2015 prices. Resource use included the initial procedures, compression therapy, primary care and outpatient consultations. The interventional procedures included superficial venous surgery, endothermal ablation and ultrasound-guided foam sclerotherapy (UGFS). The study population was patients with a chronic venous ulcer who were eligible for either compression therapy or an interventional procedure. Data were obtained from systematic review and meta-analysis of RCTs. Results Surgery gained 0·112 (95 per cent c.i. -0·011 to 0·213) QALYs compared with compression therapy alone, with a difference in lifetime costs of €-1330 (-3570 to 1262). Given the expected savings in community care, the procedure would pay for itself within 4 years. There was insufficient evidence regarding endothermal ablation and UGFS to draw conclusions. Discussion This modelling study found surgery to be more effective and less costly than compression therapy alone. Further RCT evidence is required for both endothermal ablation and UGFS.

A commercial unsaturated polyester resin, Beetle R 8592 from BIP Chemical Limited has been cured using a microwave oven. Thermal curing was also carried out as a comparative study. The cured resins were compared using differential scanning calorimetry, Fourier transform infrared spectroscopy, dynamic mechanical analysis, scanning electron microscopy, solid state NMR spectroscopy, and flexural properties. The DSC analysis showed that microwave curing was much faster than thermal curing. However, within the limits of experimental error, it was found that the shear modulus, the number average molecular weight M c, flexural modulus and strength were not significantly different. Solid state NMR also showed similar spectra for both microwave and thermal cured samples, which suggests that the same curing reactions took place in each case.

Background Single-centre series of the management of patients with ruptured abdominal aortic aneurysm (AAA) are usually too small to identify clinical factors that could improve patient outcomes. Methods IMPROVE is a pragmatic, multicentre randomized clinical trial in which eligible patients with a clinical diagnosis of ruptured aneurysm were allocated to a strategy of endovascular aneurysm repair (EVAR) or to open repair. The influences of time and manner of hospital presentation, fluid volume status, type of anaesthesia, type of endovascular repair and time to aneurysm repair on 30-day mortality were investigated according to a prespecified plan, for the subgroup of patients with a proven diagnosis of ruptured or symptomatic AAA. Adjustment was made for potential confounding factors. Results Some 558 of 613 randomized patients had a symptomatic or ruptured aneurysm: diagnostic accuracy was 91·0 per cent. Patients randomized outside routine working hours had higher operative mortality (adjusted odds ratio (OR) 1·47, 95 per cent confidence interval 1·00 to 2·17). Mortality rates after primary and secondary presentation were similar. Lowest systolic blood pressure was strongly and independently associated with 30-day mortality (51 per cent among those with pressure below 70 mmHg). Patients who received EVAR under local anaesthesia alone had greatly reduced 30-day mortality compared with those who had general anaesthesia (adjusted OR 0·27, 0·10 to 0·70). Conclusion These findings suggest that the outcome of ruptured AAA might be improved by wider use of local anaesthesia for EVAR and that a minimum blood pressure of 70 mmHg is too low a threshold for permissive hypotension.

follows: MC (p = 1.086 g ~m-~, 0.998 1 f 0.0003); PC (p = 1.30 g ~m-~, 0.9969 f 0.0022); 4dmeMC (p = 1.06 g cm-3,0.9995 f 0.0002); 5dmeMC (p = 1.06 g ~m-~, 0.9996 f 0.0001). n-Hexadecane (Aldrich Gold Label), stored under nitrogen, for which from separate measurements -&uO/J 8-1 = 47 164.4 f 1.7, was used as an auxiliary combustion aid for some of the measurements. Combustion Calorimetry. The enthalpies of combustion of MC and PC were measured using the static-bomb calorimeter in ManchesterS whereas 4dmeMC and 5dmeMC were measured

NMR is now a powerful, mature analytical tool which has widespread applications in all areas of synthetic chemistry, and polymer science is no exception. High-resolution solution-state NMR is a versatile technique which not only provides accurate qualitative and quantitative information on the chemical structure of a polymeric material, but is also capable of providing detailed information on certain aspects of chain structure which is not accessible by any other technique. The purpose of this chapter is to introduce the physical basis of the NMR phenomenon, to outline the effects that determine the form of the NMR spectra of liquid-state samples, to describe the experimental techniques of solution-state NMR of polymers, and to introduce those aspects of the structure of synthetic polymers that are specially amenable to NMR analysis.

The structure of hyaluronan was investigated in water/dimethyl sulphoxide mixtures by using high-field n.m.r. and space-filling molecular models. The secondary structure previously established in detail in ‘dry’ dimethyl sulphoxide [Heatley, Scott & Hull (1984) Biochem. J. 220, 197-205] undergoes changes on addition of water, compatible with the incorporation of a water bridge between the uronate carboxylate and acetamido NH groups. Molecular models show that such a configuration is highly probable, and saturation-transfer experiments yield rates of NH proton exchange that support this proposed structure. The existence of two distinct stable configurations for hyaluronan, in water-rich and water-poor conditions respectively, may have biological implications, e.g. during its biosynthesis in cell membranes. There are extensive hydrophobic regions in both forms, which may be important for interactions with e.g., membranes, proteins and itself.

Objective To investigate and rank factors that influence endovascular treatment decisions by specialists for patients with descending thoracic aortic aneurysm (dTAA). Methods Specialists completed a diagrammatic survey describing uncertainty about the benefit of thoracic endovascular aneurysm repair (TEVAR) for dTAA with respect to age, sex, and aneurysm diameter. Subsequently, a detailed discrete choice experiment was designed. Specialists were recruited and asked to indicate treatment their preference (TEVAR or surveillance) in 25 hypothetical cases of dTAA, with variable patient attributes: age, sex, American Society of Anesthesiologists (ASA) grade, aneurysm diameter, adequate landing zone distal to left subclavian artery (LSA), and length of aortic coverage. Data were analysed using multiple logistic regression. Results The diagrammatic survey, based on 50 respondents, showed that uncertainty about the benefits of TEVAR was greatest for patients aged 80–85 years (up to 47% of respondents were “unsure”) and that uncertainty increased with increasing aneurysm diameter (for an 80-year-old man, 7% were unsure at 5.5 cm and 33% were unsure at 7.0 cm). Seventy-one specialists (mainly from Europe and North America, 86% vascular surgeons and 98% working in units offering TEVAR) completed the discrete choice experiment. Preference for TEVAR increased greatly with enlarging diameter: adjusted odds ratios (OR) >5.5–6.0 cm = 15.8 (95% confidence interval [CI] 9.83–25.40); >6.0–6.5 cm = 393.0 (95% CI 202.00–766.00); >6.5–7.0 cm = 1829.0 (95% CI 400.00–4,181.00). TEVAR was less likely to be preferred in patients older than 75 years (>75–80 years OR 0.32, 95% CI 0.21–0.49; >80–85 years = 0.18, 95% CI 0.11–0.28); in women (OR 0.52, 95% CI 0.37–0.74); in patients classified as ASA grade 4 (OR 0.44, 95% CI 0.36–0.57); and in patients with aorta coverage >25 cm (OR 0.48, 95% CI 0.32–0.74). The proximal landing zone did not influence preference. Conclusion Specialists' preferences for endovascular repair of degenerative dTAA vary widely, and demonstrate clinical uncertainty, especially in octogenarians, and a reluctance to offer TEVAR to women. Aneurysm diameter dominates treatment preferences, but patient fitness and length of aortic coverage (>25 cm) also were influential, although the landing zone distal to LSA was not.

The 1H-n.m.r. spectra of solutions in [2H6]dimethyl sulphoxide of the sodium salts of tetra-, hexa- and octa-saccharides prepared from hyaluronate by testicular-hyaluronidase digestion were examined at 300 and 500 MHz. The signals from hydroxy groups at positions 2 and 3 in the glucuronic acid moiety were assigned. Their chemical shifts and associated temperature-dependencies, as well as their coupling constants, depended on whether or not the uronic acid was at the non-reducing end. Deviations from the ‘normal’ pattern of hydroxy-group proton n.m.r. behaviour were attributable to participation in hydrogen bonds, either to the acetamido carbonyl oxygen atom or the pyranose ring oxygen atom of neighbouring N-acetylhexosamine moieties. A secondary structure, containing four different hydrogen bonds per trisaccharide unit of glucuronsyl-hexosaminyl-glucuronic acid, was demonstrated. This is the first complete and detailed secondary structure to be established for hyaluronate in any solvent. Hyaluronate is compared with chondroitin sulphate, dermatan sulphate, heparan sulphate and keratan sulphate in their potential to form secondary structures with features in common. The significance of the details of the structure to its overall stability, and the probability of their persistence into aqueous environments, are discussed. The presence of all or most of the secondary structure in glycosaminoglycuronans is correlated with a space-filling function in the tissue, and with a high carbohydrate content in the parent proteoglycan in the case of the chondroitin sulphates.

A simple introduction to nuclear magnetic resonance in solid polymers is given. The basic theory of the n.m.r. phenomena of importance (dipole-dipole coupling, chemical shift anisotropy and magnetic relaxation) is described, and the application of these effects to polymers is illustrated by selected examples. The review covers both well-established broadline n.m.r. and recently developed solid-state high-resolution n.m.r.