Measurement of Dark Ice-Ablator Mix in Inertial Confinement Fusion

We present measurements of ice-ablator mix at stagnation of inertially confined, cryogenically layered capsule implosions. An ice layer thickness scan with layers significantly thinner than used in ignition experiments enables us to investigate mix near the inner ablator interface. Our experiments reveal for the first time that the majority of atomically mixed ablator material is "dark" mix. It is seeded by the ice-ablator interface instability and located in the relatively cooler, denser region of the fuel assembly surrounding the fusion hot spot. The amount of dark mix is an important quantity as it is thought to affect both fusion fuel compression and burn propagation when it turns into hot mix as the burn wave propagates through the initially colder fuel region surrounding an igniting hot spot. We demonstrate a significant reduction in ice-ablator mix in the hot-spot boundary region when we increase the initial ice layer thickness.

Pharmacist intervention in cardiovascular disease prevention: lipid modifying treatment optimisation in type 2 diabetes within hastings primary care network

Introduction

Cardiovascular disease (CVD) leads to 1 in 4 premature deaths with higher likelihood in the most deprived population1. Consistent data demonstrated efficacy of statins in CVD prevention and mortality reduction through modifying lipid profile1,2. NICE:CG181 recommends high-intensity statin, namely atorvastatin 20mg daily in type 2 diabetes (T2DM) with high risk of developing CVD1, whilst the European Society of Cardiology suggests LDL-C target below 1.4mmol/L, the lower the better 2. In contrast, 30% of patients in Hastings Primary Care Network (PCN) are prescribed sub-optimal statin therapy3 with scope to promote medicine optimisation through modification of CVD risk factor in one of the England’s most deprived areas.

Aim

Lowering patient’s CVD risk through optimising statin therapy and improving practice’s compliance with NICE:CG181.

Methods

NHS Health Research Authority Decision tool was followed, ethics approval was not required. Statin prescribing data were obtained through OpenPrescribing database. This pilot study focused on the prescribing of simvastatin at one surgery within the PCN where patients were identified using the surgery medical information system with the inclusion clinical codes of: “T2DM”, “QRISK2>10%”, “latest LDL-C>1.4mmol/L” and “current simvastatin 10/20/40mg prescription”. Systematic review of patient medical records was followed, including medical history, latest lipid profile and liver function, allergies, history of statin intolerance, previous lipid therapy and frailty status determined using the electronic frailty index, Rockwood score and medical notes. Patients with heterozygous familial hypercholesterolaemia diagnosis, confirmed statin intolerance and moderately-to-severely frail were excluded. Patients were contacted to exercise shared decision-making. Once intervention agreed, prescription was initiated for prescriber authorisation. Blood test 3 months post-intervention monitored for liver function and lipid profile.

Results

Search in February 2022 identified 44 patients with 39 suitable for intervention after exclusion. Thirty-six contactable patients were all switched to high-intensity statin. Thirty-four were switched to atorvastatin 20 mg whilst two with prior atorvastatin intolerance were switched to rosuvastatin 10 mg. At baseline, 32 patients (88%) had cholesterol profile done within a year as per NICE:CG181. Three-month post-intervention blood tests were completed for 21, with 15 pending; 33% (7/21) had a reduction of LDL-C.

In February 2022, 28.9% of the practice’s statin prescriptions were of low and medium intensity and was reduced to 25.6% post intervention.

Discussion/Conclusion

All contactable patients had statin therapy optimised after exercising shared decision-making with improvement of prescribing compliance to NICE:CG181 demonstrated in this practice. Findings were inconclusive whether the intensification of statin therapy demonstrated cholesterol lowering effect in this cohort. Study limitations due to small sample size, currency of baseline profile at time of intervention and patient compliance not measured. Raised LDL-C observed could have been influenced by lifestyle changes such as poor diet and lack of exercise1. The limitations of this study will be reviewed for future roll out across Hastings PCN. Further exploration of therapy compliance, lifestyle education and the barriers to regular blood test would facilitate such medicine optimisation intervention. In conclusion, patients prescribed with sub-optimal lipid therapy should be reviewed and managed through healthy lifestyle recommendations and aggressive pharmacological intervention.

References

1. National Institute for Health and Care Excellence. Cardiovascular disease: risk assessment and reduction, including lipid modification, CG181. 2016 [cited 2022 Jul 27]. Available from: https://www.nice.org.uk/guidance/cg181

2. Mach F, Baigent C, Catapano AL, Konskinas CK, Casula M, Badimon L, et al. 2019 ESC/EAS Guidelines for the management of dyslipidaemias: lipid modification to reduce cardiovascular risk: the task force for the management of dyslipidaemias of the European Society of Cardiology (ESC) and European Atherosclerosis Society (EAS). Eur Heart J [Internet]. 2019 Aug [cited 2022 Jul 27]. Available from: https://academic.oup.com/eurheartj/article/41/1/111/5556353#207091308 DOI: 10.1093/eurheartj/ehz455

3. OpenPrescribing.net. Bennett Institute for Applied Data Science. University of Oxford. [Internet]. 2022 [cited 2022 Jul 30]. Available from: https://openprescribing.net/measure/statinintensity/pcn/U99438/

National audit of non-melanoma skin cancer excisions performed by plastic surgery in the UK

A national, multi-centre audit of non-melanoma skin cancer excisions by plastic surgery.

Screening for cardiac allograft rejection among heart transplant recipients using an electrocardiogram-based deep learning model

Background

Current approaches utilizing non-invasive methods to screen for cardiac allograft rejection (gene expression profiling and cell free DNA) have yet to be broadly integrated into heart transplant management and have shown limited discrimination (AUCs of 0.68 and 0.77, respectively). Changes in the electrocardiogram (ECG) have been reported at the time of severe cardiac rejection, including low voltages and conduction abnormalities. It remains unknown if subtle ECG changes correlating with cardiac allograft rejection can be detected earlier using machine learning methods.

Purpose

We sought to develop an artificial intelligence (AI) model to detect cardiac allograft rejection based on the 12 lead ECG.

Methods

We identified all patients who underwent a heart transplant at 3 hospital sites within a single health system from Jan 1998 through Apr 2021 and extracted digital 12-lead ECG data as well as endomyocardial biopsy pathology results from the electronic medical record. We partitioned our data into a training (80%), validation (10%), and test set (10%) based on a group stratification sampling. Each patient was present in only one set and each set had a positivity rate of 2.6% with 6,074/758/758 ECGs belonging to 1,146/140/141 unique patients in each set respectively. Cardiac allograft rejection was defined as moderate or severe acute cellular rejection based on International Society for Heart and Lung Transplantation (ISHLT) guidelines. A convolutional neural network, using the 12-lead ECG data as input, was trained with hyperparameter optimization for regularization, learning rate adjustments, and class weights. Model performance metrics were based on the test data and estimated using the final model architecture.

Results

1,587 heart transplant recipients who had at least one endomyocardial biopsy were evaluated for inclusion. We limited our sample to ECGs performed within 30 days of the biopsy date (7,590 ECGs, representing 1,425 unique patients). Our study population had a median age of 55.8 years and 28.7% were female. The median number of ECG-biopsy pairs per patient was 5. The majority of endomyocardial biopsy results were classified as none or mild rejection (97.1%), and 2.9% had moderate/severe rejection. The ECG-based AI model detected cardiac allograft rejection with an area under the receiver operative curve (AUC) of 0.84 in the test set. The sensitivity, specificity, positive and negative predictive values were 95%, 52.6%. 5.2% and 99.7% respectively.

Conclusions

An AI-ECG model appears to outperform novel non-invasive laboratory tests (gene expression profiling and cell free DNA) for detecting cardiac allograft rejection and does not require a blood draw or the additional complexities surrounding sample processing. This model relies on a readily available and relatively inexpensive test, the ECG. In addition, AI predictions can be made available within a few minutes following ECG acquisition.

Funding Acknowledgement

Type of funding sources: Private hospital(s). Main funding source(s): Mayo Clinic

Hexagonal Prisms Form in Water-Ice Clouds on Mars, Producing Halo Displays Seen by Perseverance Rover

Observations by several cameras on the Perseverance rover showed a 22° scattering halo around the Sun over several hours during northern midsummer (solar longitude 142°). Such a halo has not previously been seen beyond Earth. The halo occurred during the aphelion cloud belt season and the cloudiest time yet observed from the Perseverance site. The halo required crystalline water-ice cloud particles in the form of hexagonal columns large enough for refraction to be significant, at least 11 μm in diameter and length. From a possible 40-50 km altitude, and over the 3.3 hr duration of the halo, particles could have fallen 3-12 km, causing downward transport of water and dust. Halo-forming clouds are likely rare due to the high supersaturation of water that is required but may be more common in northern subtropical regions during northern midsummer.

Prostate Volume Changes during Extreme and Moderately Hypofractionated Magnetic Resonance Image-guided Radiotherapy

AIMS

Prostate morphological changes during external beam radiotherapy are poorly understood. Excellent soft-tissue visualisation offered by magnetic resonance image-guided radiotherapy (MRIgRT) provides an opportunity to better understand such changes. The aim of this study was to quantify prostate volume and dimension changes occurring during extreme and moderately hypofractionated schedules.

MATERIALS AND METHODS

Forty prostate cancer patients treated on the Unity 1.5 Tesla magnetic resonance linear accelerator (MRL) were retrospectively reviewed. The cohort comprised patients treated with 36.25 Gy in five fractions (n = 20) and 60 Gy in 20 fractions (n = 20). The volume of the delineated prostates on reference planning computed tomography (fused with MRI) and daily T2-weighted 2-min session images acquired on Unity were charted. Forty planning computed tomography and 500 MRL prostate volumes were evaluated. The mean absolute and relative change in prostate volume during radiotherapy was compared using a paired t-test (P value <0.01 considered significant to control for multiple comparisons). The maximum dimension of the delineated prostate was measured in three isocentric planes.

RESULTS

Significant prostate volume changes, relative to MRL imaging fraction 1 (MRL#1), were seen at all time points for the five-fraction group. The peak mean relative volume increase was 21% (P < 0.001), occurring at MRL#3 and MRL#4 after 14.5 and 21.75 Gy, respectively. Prostate expansion was greatest in the superior-inferior direction; the peak mean maximal extension was 5.9 mm. The maximal extension in the left-right and anterior-posterior directions measured 1.1 and 2.2 mm, respectively. For the 20-fraction group, prostate volume increased relative to MRL#1, for all treatment time points. The mean relative volume increase was 11% (P < 0.001) at MRL#5 after 12 Gy, it then fluctuated between 8 and 13%. From MRL#5 to MRL#20, the volume increase was significant (P < 0.01) for 12 of 16 time points calculated. The peak mean maximal extension in the superior-inferior direction was 3.1 mm. The maximal extension in the left-right and anterior-posterior directions measured 1.7 and 3.7 mm, respectively.

CONCLUSION

Significant prostate volume and dimension changes occur during extreme and moderately hypofractionated radiotherapy. The extent of change was greater during extreme hypofractionation. MRIgRT offers the opportunity to reveal, quantify and correct for this deformation.

O102 We know about left gastric artery embolisation and will embio provide the next solution to treat obesity?

Introduction

Left gastric artery embolisation (LGAE) is a minimally invasive procedure which has shown promising results for weight loss in recent studies and could play a key role as a treatment option in-between our current tier-3 and tier-4 services. Imperial College NHS Trust will sponsor the EMBIO trial, the first multi-centre double blinded randomised controlled trial comparing LGAE vs Placebo procedure to evaluate its efficacy on weight loss and obesity related comorbidities over a 12 month follow up period. Here, we perform a systematic review of the existing literature.

Methods

9 studies were reviewed. Studies which investigated weight loss as a % +- Ghrelin % change at 3,6 and 12 months were included as these pre-defined time points correlate with the EMBIO protocol. 6 studies met our inclusion criteria, 5 single arm studies and 1 single blinded RCT.

Results

N=62 patients were included in our analysis. Mean weight loss reported was 8.5%, 8.8% and 10% at 3, 6 and 12 months respectively post LGAE. Ghrelin levels reduced by 36%, 16.2% and 16.5% at 3, 6 and 12 months respectively post LGAE. To date, the only reported adverse events recorded include superficial gastric erosions healed on endoscopy by day 90 and one case of subclinical pancreatitis.

Conclusion

LGAE potentially offers a day case procedure under local anaesthesia and sedation to treat obesity and its metabolic complications. The EMBIO trial will provide level 1 evidence to confirm if LGAE is a viable intervention for obesity and evaluate its safety profile.

Take-home message

Left gastric artery embolisation could be the perfect solution to treat obesity in between existing tier-3 and tier-4 treatments.

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.