Heart valve service provision in the United Kingdom and the effect of the COVID 19 pandemic; improved but must do better. A British Heart Valve Society national survey

BACKGROUND

Outpatient care for patients with heart valve disease (HVD) is best provided by valve clinics delivered by specialists. Modern day practice in the United Kingdom (UK) is currently poorly understood and has not been evaluated for nearly a decade. Furthermore, the COVID 19 pandemic changed the management of many chronic diseases, and how this has impacted patients with heart valve disease is unclear.

METHODS

A British Heart Valve Society survey was sent to 161 hospitals throughout the UK.

RESULTS

There was a general valve clinic in 46 of the 68 hospitals (68%), in 19 of 23 Heart Centres (83%) and 29 of 45 DGHs (64%). Across all settings, 3824 new patients and 17,980 follow up patients were seen in valve clinics per annum. The mean number of patients per hospital were 197 (median 150, range 48-550) for new patients and 532 (median 400, range 150-2000) for follow up. On the day echocardiography was available in 55% of valve clinics. In patients with severe HVD, serum brain natriuretic peptide (BNP) was measured routinely in 39% of clinics and exercise testing routinely performed in 49% of clinics. A patient helpline was available in 27% of clinics. 78% of centres with a valve clinic had a valve multidisciplinary team meeting (MDT). 45% centres had an MDT co-ordinator and MDT outcomes were recorded on a database in 64%. COVID-19 had a major impact on valve services in 54 (95%) hospitals.

CONCLUSIONS

There has been an increase in the number of valve clinics since 2015 from 21 to 68% but the penetration is still well short of the expected 100%, meaning that valve clinics only serve a small proportion of patients requiring surveillance for HVD. COVID-19 had a major impact on the care of patients with HVD in the majority of UK centres surveyed.

The surgical care of diabetic feet: a survey about clinics, acute care, and the surgical specialists involved

INTRODUCTION

Diabetic foot problems are becoming increasingly common. Diabetic foot care services are fundamental in managing them, and there is the further issue of acute surgery for foot sepsis. The involvement of different surgical specialists has been variable; this survey aimed to provide information about current service provision.

METHODS

Questionnaires were emailed to Vascular Society members, and targeted approaches were then undertaken.

RESULTS

We aimed to obtain information from 61 localities identified as providing shared services, and received informative responses from 46 (75%). These described diabetic foot clinics each day (11%), or once (50%), twice (13%) or three times (17%) weekly - attended regularly by vascular surgeons, and less frequently by orthopaedic surgeons. The frequency of clinics was considered inadequate by 30% of respondents, and only 75% reported written policies for diabetic foot care pathways. Operations for acute foot sepsis are done by vascular surgeons in 98% of localities and by orthopaedic surgeons in 22% (in some localities by both): the latter are orthopaedic foot specialists in all localities but two. Both specialties perform a range of foot procedures, including toe/foot-preserving operations. Major amputations are done by vascular surgeons in 98% of localities and by orthopaedic surgeons in only 9%. All deformity correction procedures are performed by orthopaedic surgeons.

CONCLUSION

This survey shows that diabetic foot clinics are now held frequently in most localities. There is variation in the involvement of vascular and orthopaedic surgeons. Some localities need to consider increased provision of clinics and better defined pathways of care.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Left ventricular ejection fraction as an imaging biomarker to guide cardiac resynchronisation therapy in heart failure patients: a multimodal comparison of 2D and 3D echocardiography and CMR

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): The authors acknowledge financial support from the Department of Health through the National Institute for Health Research (NIHR) comprehensive Biomedical Research Centre award to Guy’s & St Thomas’ NHS Foundation Trust in partnership with King’s College London and King’s College Hospital NHS Foundation Trust and by the NIHR MedTech Co-operative for Cardiovascular Disease at Guy’s and St Thomas’ NHS Foundation Trust. This work was supported by the Wellcome/EPSRC Centre for Medical Engineering [WT 203148/Z/16/Z]. MSN was funded by a clinical lectureship awarded by the NIHR. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, the DoH, EPSRC, MRC or the Wellcome Trust.

Introduction – Imaging derived left ventricular ejection fraction (LVEF) has an important role to guide initiation of medical therapy and device insertion in patients with heart failure and reduced ejection fraction (HFrEF). Previous studies have reported the correlation and agreement of LVEF in various patient populations, but sparse evidence exists on patients with heart failure referred for Cardiac Resynchronisation Therapy (CRT) using 2D and 3D echocardiography (2DE & 3DE) and cardiovascular magnetic resonance (CMR).

Objectives – To determine the correlation and agreement of LVEF as determined by 2DE, 3DE and CMR in a cohort of HF patients referred for assessment of CRT.

Methods – Patients with suspected HFrEF referred for assessment for CRT therapy were included in this single centre study. Patients underwent 2DE, 3DE and CMR to derive LVEF, LVESV and LVEDV. Correlation was determined with Pearson’s correlation, agreement with Bland-Altman analysis and Cohen’s kappa analysis for agreement using a dichotomous cut off of LVEF ≤35% as a threshold for CRT insertion (Ponikowski, 2016).

Results - 55 patients (mean age 71 ± 9.2, 76% male) were included. The mean LVEF for 2DE, 3DE, CMR and were 32.4 ± 8.6, 32.1 ± 9.6 and 30.3 ± 9.5 respectively. CMR had a significantly lower LVEF compared to 2DE (p = 0.03).

There was good correlation between 3DE & CMR and 2DE & CMR, and excellent correlation between 3DE and 2DE for LVEF (Table 1). There was for trend for CMR to underestimate LVEF compared to 2DE and 3DE, with small biases although wide limits of agreement (Figure 1). There was excellent correlation of LVEDV and LVESV across all 3 techniques. CMR underestimated volumes compared to 2DE and 3DE with large biases and wide LOA.

The kappa coefficient agreement at threshold level for CRT insertion (LVEF ≤35%) was fair for 3DE and CMR (0.379, p = 0.004) and 2DE and CMR (0.462, p = 0.001), and moderate for 3DE and 2DE (0.575, p ≤ 0.001).

Conclusion – Whilst LVEF is not the only indicator to guide CRT insertion, it remains an important imaging parameter for clinical decision making. We observed large biases in left ventricular volumes between 2D, 3D and CMR. However, whilst the overall bias in LVEF is small, the wide limits of agreement (LOA) observed may represent an area of clinical uncertainty, which may impact on the dichotomous imaging threshold for CRT insertion.

Comparison of indices between modalities LVEF Correlation (r) LVEF Bias & LOA (%±SD) EDV Correlation (r) EDV Bias & LOA (mL ± SD) ESV Correlation (r) ESV Bias & LOA (mL ± SD) 3DE vs CMR 0.676 (p < 0.001) +1.75 ± 15.4 0.896 (p < 0.001) -82.16 ± 42.8 0.937 (p < 0.001) -61.3 ± 34.9 3DE vs 2DE 0.872 (p < 0.001) +0.48 ± 4.5 0.909 (p < 0.001) -10.31 ± 28.3 0.936 (p < 0.001) -8.42 ± 20.5 2DE vs CMR 0.675 (p < 0.001) +2.35 ± 14.6 0.876 (p < 0.001) -67.35 ± 36.3 0.898 (p < 0.001) -51.42 ± 30.1 Abstract Figure. Bland-Altman Plot LVEF by 3DE & CMR

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Somatic gene editing ameliorates skeletal and cardiac muscle failure in pig and human models of Duchenne muscular dystrophy

Frameshift mutations in the DMD gene, encoding dystrophin, cause Duchenne muscular dystrophy (DMD), leading to terminal muscle and heart failure in patients. Somatic gene editing by sequence-specific nucleases offers new options for restoring the DMD reading frame, resulting in expression of a shortened but largely functional dystrophin protein. Here, we validated this approach in a pig model of DMD lacking exon 52 of DMD (DMDΔ52), as well as in a corresponding patient-derived induced pluripotent stem cell model. In DMDΔ52 pigs1, intramuscular injection of adeno-associated viral vectors of serotype 9 carrying an intein-split Cas9 (ref. 2) and a pair of guide RNAs targeting sequences flanking exon 51 (AAV9-Cas9-gE51) induced expression of a shortened dystrophin (DMDΔ51-52) and improved skeletal muscle function. Moreover, systemic application of AAV9-Cas9-gE51 led to widespread dystrophin expression in muscle, including diaphragm and heart, prolonging survival and reducing arrhythmogenic vulnerability. Similarly, in induced pluripotent stem cell-derived myoblasts and cardiomyocytes of a patient lacking DMDΔ52, AAV6-Cas9-g51-mediated excision of exon 51 restored dystrophin expression and amelioreate skeletal myotube formation as well as abnormal cardiomyocyte Ca2+ handling and arrhythmogenic susceptibility. The ability of Cas9-mediated exon excision to improve DMD pathology in these translational models paves the way for new treatment approaches in patients with this devastating disease.

Compliance with NICE guidelines when commissioning varicose vein procedures

Background

Varicose veins impair quality of life and can lead to chronic leg ulcers. National Institute for Health and Care Excellence (NICE) guidelines (CG168) set out evidence-based standards for patient management. In England, Clinical Commissioning Groups (CCGs) fund NHS care within their locality. The objective of this study was to evaluate CCGs' commissioning policies and compare them with CG168.

Methods

Searches were made for the published policies of all 206 English CCGs. They were reviewed for compliance with NICE guidelines and the associated quality standard. Areas of disagreement were analysed for themes.

Results

Some 203 CCGs (98·5 per cent) had a published policy and 190 (93·6 per cent) of these were published after publication of CG168. Only 73 of the policies (36·0 per cent) were compliant with CG168. Treatment was restricted on the basis of clinical disease severity in 119 CCGs (58·6 per cent); 29 (14·3 per cent) stipulated delay of treatment using a 'trial' of conservative treatment; 22 (10·8 per cent) used lifestyle-related factors such as BMI and smoking status to ration treatment. Treatment was commissioned for uncomplicated symptomatic varicose veins in 87 CCGs (42·9 per cent), but some applied additional rationing mechanisms; 109 CCGs (53·7 per cent) would treat oedema, 183 (90·1 per cent) would treat skin and soft tissue damage, 202 (99·5 per cent) healed ulceration, and all would allow active ulcers to be treated.

Discussion

The majority of CCGs in England have commissioning policies that contradict NICE guidelines. Rationing strategies include disease severity, delay and patient lifestyle-related factors, creating unwarranted geographical variation for varicose vein treatment, disregarding the NHS Constitution for England, and perhaps leading to an increase in costly treatment of chronic complications in the long term.

Introduction into the NHS of magnetic sphincter augmentation: an innovative surgical therapy for reflux - results and challenges

Introduction Gastro-oesophageal reflux disease (GORD) is a common, chronic debilitating condition. Surgical management traditionally involves fundoplication. Magnetic sphincter augmentation (MSA) is a new definitive treatment. We describe our experience of introducing this innovative therapy into NHS practice and report the early clinical outcomes. Methods MSA was introduced into NHS practice following successful acceptance of a cost-effective business plan and close observation of National Institute for Health and Care Excellence (NICE) recommendations for new procedures, including a carefully planned prospective data collection over a two-year follow-up period. Results Forty-seven patients underwent MSA over the 40-month period. Reflux health-related quality of life (GERD-HRQL) was significantly improved after the procedure and maintained at one- and two-year (P < 0.0001) follow-up. Drug dependency went from 100% at baseline to 2.6% and 8.7% after one and two years. High levels of patient satisfaction were reported. There were no adverse events. Conclusions MSA is highly effective in the treatment of uncomplicated GORD, with durable results and an excellent safety profile. This laparoscopic, minimally invasive procedure provides a good alternative for patients where surgical anatomy is unaltered. Our experience demonstrates that innovative technology can be incorporated into NHS practice with an acceptable business plan and compliance with NICE recommendations.

Factors influencing the choice of treatment modality for individual patients with varicose veins

INTRODUCTION There is evidence of effectiveness for a range of different treatment modalities for varicose veins but limited information about factors that influence treatment choice for individual patients. METHODS A postal survey was sent to 438 UK members of the Vascular Society of Great Britain and Ireland. RESULTS Overall, 251 responses were received (response rate 57%). A total of 222 respondents treated varicose veins using conventional surgery (84%), endothermal ablation (82%) and foam sclerotherapy (68%). The clinical pattern of veins appeared to have the greatest influence on treatment choice. This was followed by guidance from the National Institute for Health and Care Excellence, patient expectations, facilities, cost and whether treatment was carried out in the public or private sector. Respondents were asked to indicate whether each of 13 clinical 'scenarios' (eg very extensive varicose veins in both legs) would influence them towards or against using specified treatment modalities. 'Consensus' was defined as ≥80% of responses either towards or against any treatment modality; and disagreement as 41-59% both towards and against any modality (i.e. ∼50:50 split). There was consensus towards using endothermal ablation for truncal reflux, towards UGFS for localised varicose veins and towards conventional surgery for large, extensive, bilateral veins. There was consensus against UGFS for large truncal veins, and against surgery for obese patients and those with a history of venous thromboembolism. There were important disagreements about the influence of large or extensive veins, about whether patients were obese or slim and about a prior history of venous thromboembolism. CONCLUSIONS Conventional surgery is still widely available in the UK. Disagreements about treatment choice in different clinical scenarios suggest substantial variation in the treatments patients are offered. Attention to identifying subgroups in trials would help to guide treatment choice for individual patients.

Anxiety associated with diagnostic uncertainty in early pregnancy

OBJECTIVES

To determine anxiety levels of women presenting to an early pregnancy assessment unit (EPAU) with abdominal pain and/or vaginal bleeding and to assess how these levels change over time and according to ultrasonographic diagnosis.

METHODS

We undertook a prospective cohort study in an EPAU in a large UK teaching hospital. Women with abdominal pain and/or vaginal bleeding in early pregnancy (< 12 weeks' gestation) presenting for the first time were eligible for inclusion in the study. State anxiety levels were assessed using the standardized short form of Spielberger's state-trait anxiety inventory (STAI) on three occasions (before, immediately after and 48-72 hours after an ultrasound scan). Scores were correlated with ultrasonographic diagnosis. The diagnosis was either certain or uncertain. Certain diagnoses were either positive, i.e. a viable intrauterine pregnancy (IUP), or negative, i.e. a non-viable IUP or ectopic pregnancy. Uncertain diagnoses included pregnancy of unknown location and pregnancy of uncertain viability. Statistical analysis involved mixed ANOVAs and the post-hoc Tukey-Kramer test.

RESULTS

A total of 160 women were included in the study. Anxiety levels decreased over time for women with a certain diagnosis (n = 128), even when negative (n = 64), and increased over time for women with an uncertain diagnosis (n = 32). Before the ultrasound examination, anxiety levels were high (STAI value, 21.96 ± 1.11) and there was no significant difference between the five groups. Immediately after the ultrasound examination, anxiety levels were lower in the viable IUP group (n = 64; 7.75 ± 1.13) than in any other group. The difference between the five groups was significant (P < 0.005). After 48-72 hours, women with a certain diagnosis had significantly lower anxiety levels than had those with an uncertain diagnosis (10.77 ± 4.30 vs 22.94 ± 1.65; P < 0.005).

CONCLUSIONS

The experience of abdominal pain and/or vaginal bleeding in early pregnancy is highly anxiogenic. Following an ultrasound examination, the certainty of the diagnosis affects anxiety levels more than does the positive or negative connotations associated with the diagnosis per se. Healthcare providers should be aware of this when communicating uncertain diagnoses. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Use of double decidual sac sign to confirm intrauterine pregnancy location prior to sonographic visualization of embryonic contents

OBJECTIVES

To determine the diagnostic accuracy of the double decidual sac sign (DDSS) for predicting an intrauterine pregnancy (IUP) prior to visualization of embryonic contents, using modern high-resolution transvaginal sonography (TVS).

METHODS

The study was conducted following STARD guidelines and participants were recruited prospectively from Nurture Fertility, Nottingham, UK, following in-vitro fertilization/intracytoplasmic sperm injection treatment between 1 January 2015 and 31 October 2015. Women were excluded if there was no evidence of intrauterine fluid collection during the index test, a yolk sac or fetal pole was visible during the index test, no outcome data were available or pregnancy location could not be determined by the reference standard. The index test consisted of TVS at 32-34 days' gestation using a high-frequency transvaginal probe. Reference standard was TVS at 7 weeks' gestation. The outcome of interest was an IUP.

RESULTS

A total of 67 intrauterine fluid collections were observed and included in the analysis, of which 61 exhibited the DDSS and 65 were proven to be IUPs. Two ectopic pregnancies were included, neither of which demonstrated the DDSS. The DDSS therefore had a sensitivity of 93.9% (95% CI, 85.0-98.3%), specificity of 100% (95% CI, 15.8-100%) and overall diagnostic accuracy of 94.0% (95% CI, 88.3-99.7%) for predicting an IUP. The negative likelihood ratio and positive and negative predictive values were 0.06 (95% CI, 0.02-0.16), 100% (95% CI, 94.1-100%) and 33.3% (95% CI, 4.3-77.7%), respectively.

CONCLUSION

With modern high-resolution TVS, presence of the DDSS can be used to confirm accurately IUP location prior to sonographic visualization of embryonic contents, and therefore to exclude effectively ectopic pregnancy. Absence of the DDSS, however, does not preclude an IUP. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Effects of carvedilol on structural and functional outcomes and plasma biomarkers in the mouse transverse aortic constriction heart failure model

Introduction:

Despite the widespread use of the mouse transverse aortic constriction heart failure model, there are no reports on the characterization of the standard-of-care agent carvedilol in this model.

Methods:

Left ventricular pressure overload was produced in mice by transverse aortic constriction between the innominate and left common carotid arteries. Carvedilol was administered at multiple dose levels (3, 10 and 30 mg/kg/day per os; yielding end-study mean plasma concentrations of 0.002, 0.015 and 0.044 µM, respectively) in a therapeutic design protocol with treatment initiated after the manifestation of left ventricular remodeling at 3 weeks post transverse aortic constriction and continued for 10 weeks.

Results:

Carvedilol treatment in transverse aortic constriction mice significantly decreased heart rate and left ventricular dP/dt (max) at all dose levels consistent with β-adrenoceptor blockade. The middle dose of carvedilol significantly decreased left ventricular weight, whereas the higher dose decreased total heart, left and right ventricular weight and wet lung weight compared to untreated transverse aortic constriction mice. The higher dose of carvedilol significantly increased cardiac performance as measured by ejection fraction and fractional shortening and decreased left ventricular end systolic volume consistent with the beneficial effect on cardiac function. End-study plasma sST-2 and Gal-3 levels did not differ among sham, transverse aortic constriction control and transverse aortic constriction carvedilol groups. Plasma brain natriuretic peptide concentrations were elevated significantly in transverse aortic constriction control animals (~150%) compared to shams in association with changes in ejection fraction and heart weight and tended to decrease (~30%, p = 0.10–0.12) with the mid- and high-dose carvedilol treatment.

Conclusion:

A comparison of carvedilol hemodynamic and structural effects in the mouse transverse aortic constriction model versus clinical use indicates a strong agreement in effect profiles preclinical versus clinical, providing important translational validation for this widely used animal model. The present plasma brain natriuretic peptide biomarker findings support the measurement of plasma natriuretic peptides in the mouse transverse aortic constriction model to extend the translational utility of the model.

Observation of Classical-Quantum Crossover of 1/f Flux Noise and Its Paramagnetic Temperature Dependence

By analyzing the dissipative dynamics of a tunable gap flux qubit, we extract both sides of its two-sided environmental flux noise spectral density over a range of frequencies around 2k_{B}T/h≈1  GHz, allowing for the observation of a classical-quantum crossover. Below the crossover point, the symmetric noise component follows a 1/f power law that matches the magnitude of the 1/f noise near 1 Hz. The antisymmetric component displays a 1/T dependence below 100 mK, providing dynamical evidence for a paramagnetic environment. Extrapolating the two-sided spectrum predicts the linewidth and reorganization energy of incoherent resonant tunneling between flux qubit wells.

Measurement-Induced State Transitions in a Superconducting Qubit: Beyond the Rotating Wave Approximation

Many superconducting qubit systems use the dispersive interaction between the qubit and a coupled harmonic resonator to perform quantum state measurement. Previous works have found that such measurements can induce state transitions in the qubit if the number of photons in the resonator is too high. We investigate these transitions and find that they can push the qubit out of the two-level subspace, and that they show resonant behavior as a function of photon number. We develop a theory for these observations based on level crossings within the Jaynes-Cummings ladder, with transitions mediated by terms in the Hamiltonian that are typically ignored by the rotating wave approximation. We find that the most important of these terms comes from an unexpected broken symmetry in the qubit potential. We confirm the theory by measuring the photon occupation of the resonator when transitions occur while varying the detuning between the qubit and resonator.

Thrombolysis and thrombectomy in patients treated with dabigatran with acute ischemic stroke: Expert opinion

Systemic thrombolysis with rt-PA is contraindicated in patients with acute ischemic stroke anticoagulated with dabigatran. This expert opinion provides guidance on the use of the specific reversal agent idarucizumab followed by rt-PA and/or thrombectomy in patients with ischemic stroke pre-treated with dabigatran. The use of idarucizumab followed by rt-PA is covered by the label of both drugs.

The effects of growing up on a farm on adult lung function and allergic phenotypes: an international population-based study

RATIONALE

Evidence has suggested that exposure to environmental or microbial biodiversity in early life may impact subsequent lung function and allergic disease risk.

OBJECTIVES

To investigate the influence of childhood living environment and biodiversity indicators on atopy, asthma and lung function in adulthood.

METHODS AND MEASUREMENTS

The European Community Respiratory Health Survey II investigated ∼10 201 participants aged 26-54 years from 14 countries, including participants' place of upbringing (farm, rural environment or inner city) before age 5 years. A 'biodiversity score' was created based on childhood exposure to cats, dogs, day care, bedroom sharing and older siblings. Associations with lung function, bronchial hyper-responsiveness (BHR), allergic sensitisation, asthma and rhinitis were analysed.

MAIN RESULTS

As compared with a city upbringing, those with early-life farm exposure had less atopic sensitisation (adjusted OR 0.46, 95% CI 0.37 to 0.58), atopic BHR (0.54 (0.35 to 0.83)), atopic asthma (0.47 (0.28 to 0.81)) and atopic rhinitis (0.43 (0.32 to 0.57)), but not non-atopic outcomes. Less pronounced protective effects were observed for rural environment exposures. Women with a farm upbringing had higher FEV₁ (adjusted difference 110 mL (64 to 157)), independent of sensitisation and asthma. In an inner city environment, a higher biodiversity score was related to less allergic sensitisation.

CONCLUSIONS

This is the first study to report beneficial effects of growing up on a farm on adult FEV₁. Our study confirmed the beneficial effects of early farm life on sensitisation, asthma and rhinitis, and found a similar association for BHR. In persons with an urban upbringing, a higher biodiversity score predicted less allergic sensitisation, but to a lesser magnitude than a childhood farm environment.

Abstract 262: A Rat Model of Heart Failure With Preserved Ejection Fraction Induced by Pressure Overload

The absence of animal models displaying clinical phenotypes of HFpEF represents a challenge to the pharmaceutical industry in the hope of identifying novel treatments that would benefit patients with this syndrome. We, at Merck, examined the supracoronary aortic banding (SAB) in rats as a potential model and set out to characterize its phenotypes. Juvenile Sprague-Dawley rats were used; a hemostatic clip with an opening of 0.7 mm was placed around the ascending aorta to elicit a pressure overload to the LV. Echocardiography was performed every 3 weeks and invasive hemodynamics was measured at week 9 to evaluate cardiac structural and functional effects; heart and lungs were harvested at the end for morphological and histological analysis. Nine weeks after SAB, LV hypertrophy and dysfunction were apparent, as manifested by increases in LVEDP, left atrial pressure, plasma BNP, LV and lung weights; LV relaxation time constant (Tau) and mitral early to late inflow ratio (E/A) were also increased; while EF and FS were preserved (see table, mean ± SEM). In addition, SAB rats had elevated mean pulmonary pressure (sham 14 ± 1.7 vs. SAB 37 ± 4.4 mm Hg, p<0.05) with an abnormal transpulmonary gradient (sham 12 ± 2.5 vs. SAB 23 ± 0.1 mm Hg, p<0.05), indicating comorbidity of pulmonary hypertension. Finally, piloerection, dyspnea and loss of muscle mass were evident and exercise tolerance measured by treadmill test was decreased in SAB rats. In summary, rats undergoing SAB exhibit many of the clinical phenotypes of HFpEF. Further work includes examining the effects of novel therapies in SAB rats on improving these clinical phenotypes of HFpEF and expanding the model to study morbidity and mortality.

Measuring and Suppressing Quantum State Leakage in a Superconducting Qubit

Leakage errors occur when a quantum system leaves the two-level qubit subspace. Reducing these errors is critically important for quantum error correction to be viable. To quantify leakage errors, we use randomized benchmarking in conjunction with measurement of the leakage population. We characterize single qubit gates in a superconducting qubit, and by refining our use of derivative reduction by adiabatic gate pulse shaping along with detuning of the pulses, we obtain gate errors consistently below 10^{-3} and leakage rates at the 10^{-5} level. With the control optimized, we find that a significant portion of the remaining leakage is due to incoherent heating of the qubit.

The march from early life food sensitization to allergic disease: a systematic review and meta-analyses of birth cohort studies

BACKGROUND

There is growing evidence for an increase in food allergies. The question of whether early life food sensitization, a primary step in food allergies, leads to other allergic disease is a controversial but important issue. Birth cohorts are an ideal design to answer this question.

OBJECTIVES

We aimed to systematically investigate and meta-analyse the evidence for associations between early food sensitization and allergic disease in birth cohorts.

METHODS

MEDLINE and SCOPUS databases were searched for birth cohorts that have investigated the association between food sensitization in the first 2 years and subsequent wheeze/asthma, eczema and/or allergic rhinitis. We performed meta-analyses using random-effects models to obtain pooled estimates, stratified by age group.

RESULTS

The search yielded fifteen original articles representing thirteen cohorts. Early life food sensitization was associated with an increased risk of infantile eczema, childhood wheeze/asthma, eczema and allergic rhinitis and young adult asthma. Meta-analyses demonstrated that early life food sensitization is related to an increased risk of wheeze/asthma (pooled OR 2.9; 95% CI 2.0-4.0), eczema (pooled OR 2.7; 95% CI 1.7-4.4) and allergic rhinitis (pooled OR 3.1; 95% CI 1.9-4.9) from 4 to 8 years.

CONCLUSION

Food sensitization in the first 2 years of life can identify children at high risk of subsequent allergic disease who may benefit from early life preventive strategies. However, due to potential residual confounding in the majority of studies combined with lack of follow-up into adolescence and adulthood, further research is needed.

Digital quantum simulation of fermionic models with a superconducting circuit

One of the key applications of quantum information is simulating nature. Fermions are ubiquitous in nature, appearing in condensed matter systems, chemistry and high energy physics. However, universally simulating their interactions is arguably one of the largest challenges, because of the difficulties arising from anticommutativity. Here we use digital methods to construct the required arbitrary interactions, and perform quantum simulation of up to four fermionic modes with a superconducting quantum circuit. We employ in excess of 300 quantum logic gates, and reach fidelities that are consistent with a simple model of uncorrelated errors. The presented approach is in principle scalable to a larger number of modes, and arbitrary spatial dimensions.

Systematic review of compression following treatment for varicose veins

Background

Consensus regarding compression following treatment of varicose veins has yet to be reached. This systematic review aims to establish the optimal compression regimen after venous treatment.

Methods

A systematic review of MEDLINE, Embase and CENTRAL was performed to identify randomized clinical trials (RCTs) investigating different compression strategies following treatment for superficial venous insufficiency.

Results

Seven RCTs comparing different durations and methods of compression fulfilled the inclusion criteria. The treatment modality was open surgery in three trials, foam sclerotherapy in two and endovenous laser ablation (EVLA) in two trials. The quality of the studies was variable, and significant sources of potential bias were present. Both the studies and compression regimens used were heterogeneous. Ten products were used in six general regimens for a duration of 0–42 days. One study suggested that 7 days rather than 2 days of stockings following EVLA was associated with superior quality of life and less pain at 1 week. Another study reported that, following surgery, application of a compression stocking after 3 days of bandaging was associated with a slightly longer recovery than no compression after 3 days. One study recorded compliance clearly, finding it to be only 40 per cent. The quality and heterogeneity of the studies precluded meta-analysis.

Conclusion

There is currently little quality evidence upon which to base any recommendations concerning compression following treatment for varicose veins.

State preservation by repetitive error detection in a superconducting quantum circuit

Quantum computing becomes viable when a quantum state can be protected from environment-induced error. If quantum bits (qubits) are sufficiently reliable, errors are sparse and quantum error correction (QEC) is capable of identifying and correcting them. Adding more qubits improves the preservation of states by guaranteeing that increasingly larger clusters of errors will not cause logical failure-a key requirement for large-scale systems. Using QEC to extend the qubit lifetime remains one of the outstanding experimental challenges in quantum computing. Here we report the protection of classical states from environmental bit-flip errors and demonstrate the suppression of these errors with increasing system size. We use a linear array of nine qubits, which is a natural step towards the two-dimensional surface code QEC scheme, and track errors as they occur by repeatedly performing projective quantum non-demolition parity measurements. Relative to a single physical qubit, we reduce the failure rate in retrieving an input state by a factor of 2.7 when using five of our nine qubits and by a factor of 8.5 when using all nine qubits after eight cycles. Additionally, we tomographically verify preservation of the non-classical Greenberger-Horne-Zeilinger state. The successful suppression of environment-induced errors will motivate further research into the many challenges associated with building a large-scale superconducting quantum computer.

Enhanced inhibitory control by neuropeptide Y Y5 receptor blockade in rats

RATIONALE

The neuropeptide Y (NPY) system acts in synergy with the classic neurotransmitters to regulate a large variety of functions including autonomic, affective, and cognitive processes. Research on the effects of NPY in the central nervous system has focused on food intake control and affective processes, but growing evidence of NPY involvement in attention-deficit/hyperactivity disorder (ADHD) and other psychiatric conditions motivated the present study.

OBJECTIVES

We tested the effects of the novel and highly selective NPY Y5 receptor antagonist Lu AE00654 on impulsivity and the underlying cortico-striatal circuitry in rats to further explore the possible involvement of the NPY system in pathologies characterized by inattention and impulsive behavior.

RESULTS

A low dose of Lu AE00654 (0.03 mg/kg) selectively facilitated response inhibition as measured by the stop-signal task, whereas no effects were found at higher doses (0.3 and 3 mg/kg). Systemic administration of Lu AE00654 also enhanced the inhibitory influence of the dorsal frontal cortex on neurons in the caudate-putamen, this fronto-striatal circuitry being implicated in the executive control of behavior. Finally, by locally injecting a Y5 agonist, we observed reciprocal activation between dorsal frontal cortex and caudate-putamen neurons. Importantly, the effects of the Y5 agonist were attenuated by pretreatment with Lu AE00654, confirming the presence of Y5 binding sites modulating functional interactions within frontal-subcortical circuits.

CONCLUSIONS

These results suggest that the NPY system modulates inhibitory neurotransmission in brain areas important for impulse control, and may be relevant for the treatment of pathologies such as ADHD and drug abuse.

Compression regimes after endovenous ablation for superficial venous insufficiency – A survey of members of the Vascular Society of Great Britain and Ireland

Introduction

The optimal compression regime following ultrasound guided foam sclerotherapy (UGFS), radiofrequency ablation (RFA) and endovenous laser ablation (EVLA) for varicose veins is not known. The aim of this study was to document current practice.

Methods

Postal questionnaire sent to 348 consultant members of the Vascular Society of Great Britain and Ireland.

Results

Valid replies were received from 41% ( n = 141) surgeons representing at least 68 (61%) vascular units. UGFS was used by 74% surgeons, RFA by 70% and EVLA by 32%, but fewer patients received UGFS (median 30) annually, than endothermal treatment (median 50) – P = 0.019. All surgeons prescribed compression: following UGFS for median seven days (range two days to three months) and after endothermal ablation for 10 days (range two days to six weeks) – P = 0.298. Seven different combinations of bandages, pads and compression stockings were reported following UGFS and four after endothermal ablation. Some surgeons advised changing from bandages to stockings from five days (range 1–14) after UGFS. Following endothermal ablation, 71% used bandages only, followed by compression stockings after two days (range 1–14). The majority of surgeons (87%) also treated varicose tributaries: 65% used phlebectomy, the majority (65%) synchronously with endothermal ablation. Concordance of compression regimes between surgeons within vascular units was uncommon. Only seven units using UGFS and six units using endothermal ablation had consistent compression regimes.

Conclusion

Compression regimes after treatments for varicose veins vary significantly: more evidence is needed to guide practice.

Qubit Architecture with High Coherence and Fast Tunable Coupling

We introduce a superconducting qubit architecture that combines high-coherence qubits and tunable qubit-qubit coupling. With the ability to set the coupling to zero, we demonstrate that this architecture is protected from the frequency crowding problems that arise from fixed coupling. More importantly, the coupling can be tuned dynamically with nanosecond resolution, making this architecture a versatile platform with applications ranging from quantum logic gates to quantum simulation. We illustrate the advantages of dynamical coupling by implementing a novel adiabatic controlled-z gate, with a speed approaching that of single-qubit gates. Integrating coherence and scalable control, the introduced qubit architecture provides a promising path towards large-scale quantum computation and simulation.

CD14 polymorphisms, microbial exposure and allergic diseases: a systematic review of gene-environment interactions

Asthma and allergy may develop as a result of interactions between environmental factors and the genetic characteristics of an individual. This review aims to summarize the available evidence for, and potential effects of, an interaction between polymorphisms of the CD14 gene and exposure to microbes on the risk of asthma and allergic diseases. We searched PubMed, MEDLINE and Global Health databases, finding 12 articles which met inclusion criteria. Most studies reported a significant interaction between CD14 polymorphisms and microbial exposure. When stratified by age at microbial exposure (early life vs adult life), there was evidence of a protective effect of gene-environment interaction against atopy in children, but not adults. We also found different effects of interaction depending on the type of microbial exposures. There was no strong evidence for asthma and eczema. Future studies should consider a three-way interaction between CD14 gene polymorphisms, microbial exposures and the age of exposure.

Cost-effectiveness of ultrasound-guided foam sclerotherapy, endovenous laser ablation or surgery as treatment for primary varicose veins from the randomized CLASS trial

Background

The treatment of patients with varicose veins constitutes a considerable workload and financial burden to the National Health Service. This study aimed to assess the cost-effectiveness of ultrasound-guided foam sclerotherapy (UGFS) and endovenous laser ablation (EVLA) compared with conventional surgery as treatment for primary varicose veins.

Methods

Participant cost and utility data were collected alongside the UK CLASS multicentre randomized clinical trial, which compared EVLA, surgery and UGFS. Regression methods were used to estimate the effects of the alternative treatments on costs to the health service and quality-adjusted life-years (QALYs) at 6 months. A Markov model, incorporating available evidence on clinical recurrence rates, was developed to extrapolate the trial data over a 5-year time horizon.

Results

Compared with surgery at 6 months, UGFS and EVLA reduced mean costs to the health service by £655 and £160 respectively. When additional overhead costs associated with theatre use were included, these cost savings increased to £902 and £392 respectively. UGFS produced 0·005 fewer QALYs, whereas EVLA produced 0·011 additional QALYs. Extrapolating to 5 years, EVLA was associated with increased costs and QALYs compared with UGFS (costing £3640 per QALY gained), and generated a cost saving (£206–439) and QALY gain (0·078) compared with surgery. Applying a ceiling willingness-to-pay ratio of £20 000 per QALY gained, EVLA had the highest probability (78·7 per cent) of being cost-effective.

Conclusion

The results suggest, for patients considered eligible for all three treatment options, that EVLA has the highest probability of being cost-effective at accepted thresholds of willingness to pay per QALY.

New evidence on treatments for varicose veins

Still inconclusive

Optimal quantum control using randomized benchmarking

We present a method for optimizing quantum control in experimental systems, using a subset of randomized benchmarking measurements to rapidly infer error. This is demonstrated to improve single- and two-qubit gates, minimize gate bleedthrough, where a gate mechanism can cause errors on subsequent gates, and identify control crosstalk in superconducting qubits. This method is able to correct parameters so that control errors no longer dominate and is suitable for automated and closed-loop optimization of experimental systems.

Salvage of the PWI/DWI mismatch up to 48 h from stroke onset leads to favorable clinical outcome

BACKGROUND AND PURPOSE

In acute ischemic stroke perfusion/diffusion-weighted image, mismatch using magnetic resonance imaging approximates the ischemic penumbra. For early time windows, mismatch salvage improves clinical outcomes, but uncertainty exists at later time epochs. We hypothesized that (a) mismatch may exist up to 48 h; (b) the proportion of mismatch salvage is time independent; and (c) when salvaged, it improves clinical outcomes.

METHODS

Magnetic resonance imaging was performed within 48 h of ischemic stroke. Perfusion-weighted image was defined by relative Tmax two-second delay. Perfusion/diffusion-weighted image mismatch was the perfusion-weighted image not overlapped by the diffusion-weighted image when coregistered. Infarct volume and disability (modified Rankin Score) were assessed at three-months. Mismatch salvage was the region not overlapped by final infarction. Favorable outcome was defined as modified Rankin Score 0-1.

RESULTS

Sixty-six patients were studied [mean age 69.9 years (standard deviation 13.1), initial median National Institute of Health Stroke Scale 9.0 (interquartile range 6.0, 18.3)]. There was no relationship between time of stroke onset and the proportion of mismatch salvaged (P = 0.73). Age (adjusted odds ratio = 0.92, 95% confidence interval 0.86-0.98, P = 0.01), initial National Institute of Health Stroke Scale (adjusted odds ratio = 0.80, 95% confidence interval 0.70-0.92, P < 0.01), mismatch volume (adjusted odds ratio = 0.98, 95% confidence interval 0.968-0.1, P = 0.05), and percentage of mismatch salvage (adjusted odds ratio = 1.04, 95% confidence interval 0.99-1.07, P = 0.05) were independently associated with favorable outcome.

CONCLUSION

Using coregistered perfusion/diffusion-weighted image criteria, mismatch persists up to 48 h post stroke. For the whole group, the proportion of mismatch salvage remains independent of time and, although the effect is small, its salvage is independently associated with improved clinical outcomes at three-months. Larger sample sizes are needed to determine the time limit for mismatch salvage.

Surgical aphorisms

A Christmas cracker

Effect of procedure volume on outcomes after iliac artery angioplasty and stenting

Background

Service reorganization to concentrate complex vascular services in hospitals with high caseload volume aims to reduce mortality and complication rates. The present study assessed the relationship between caseload volume and outcome for iliac artery angioplasty and stenting in England using a routinely available national data set (Hospital Episode Statistics, HES).

Methods

Routine administrative data for iliac artery angioplasty and stent procedures performed in England between 2007 and 2011 were analysed. Associations between centre volume and outcomes (death, complications and duration of hospital stay) were tested and compared for two methods of stratification (quartiles and quintiles) and two statistical tests (odds ratios and the Cochran–Armitage test for trend). Multivariable analysis was also performed.

Results

There were 23 308 episodes of care recorded in HES with Office of Population Censuses and Surveys Classification of Surgical Operations and Procedures, fourth revision, codes L54.1 or L54.4 corresponding to iliac artery intervention. There was a gradual increase year by year in number of procedures performed. Univariable and multivariable analysis showed no association between centre volume and either death or complications (multivariable odds ratio, OR 1·00, 95 per cent confidence interval 1·00 to 1·00) for elective and non-elective procedures. Age was associated with higher mortality and complication rates in elective procedures, and with mortality in non-elective procedures. The risk of death after elective iliac angioplasty or stenting was significantly higher in women (multivariable OR 4·98, 2·09 to 13·26).

Conclusion

There was no association between the outcomes of endovascular iliac artery intervention and centre volume, but outcomes were significantly worse with increasing age and female sex.