Paediatric tibial shaft fractures: an instructional review for the FRCS exam

This instructional review presents the literature and guidelines relevant to the classification, management and prognosis of paediatric tibial shaft fractures at a level appropriate for the FRCS exit examination in Trauma and Orthopaedic surgery.

Paediatric distal radius fractures: an instructional review for the FRCS examination

An instructional review of the literature and guidelines relevant for the classification, management and prognosis of paediatric distal radius fractures. Aimed at the knowledge level required for the trauma and orthopaedic FRCS examination.

Associations between DAPT score and long-term mortality post PCI

Introduction

The dual antiplatelet therapy (DAPT) score was developed to identify patients more likely to derive benefit (score ≥2) or harm (score <2) from DAPT beyond 1-year post PCI. There is no study which looked at the DAPT score and long term outcomes post PCI in Australia.

Purpose

We sought to examine long-term mortality after PCI by the DAPT score in patients treated with DAPT per local guidelines.

Methods

We examined data from the MIG PCI database from 2005 to 2018 in whom the DAPT score could be derived and grouped them as score ≥2 or <2. Long-term mortality was assessed from National Death Index linkage. The primary endpoint was long-term mortality examined using survival analysis. Secondary endpoints included 30-day ischaemic outcomes and in-hospital major bleeding.

Results

Out of 27,740 patients in the study, 9,401 (33.9%) had DAPT score ≥2. They were younger and included more females and higher prevalence of renal impairment. DAPT score ≥2 patients had higher in-hospital major bleeding, 30-day mortality, MI and target vessel revascularisation. DAPT score ≥2 patients had lower long-term survival to 12 years (p<0.001 for all).

Conclusion

A third of all-comer PCI patients had DAPT score ≥2 with greater short-term risk of ischaemic and bleeding outcomes, as well as long-term mortality. Theoretically, those with DAPT score ≥2 would benefit from longer duration of DAPT as ischaemic risk outweighs bleeding risk. However, given our finding of increased short-term bleeding risk and long-term mortality, dynamic bleeding risk assessment should be undertaken to guide pharmacotherapy strategies.

Funding Acknowledgement

Type of funding sources: None.

Genomic evidence of recent European introgression into North American farmed and wild Atlantic Salmon

Gene flow between wild and domestic populations has been repeatedly demonstrated across a diverse range of taxa. Ultimately, the genetic impacts of gene flow from domestic into wild populations depend both on the degree of domestication and the original source of the domesticated population. Atlantic salmon, Salmo salar, used in North American aquaculture are ostensibly of North American origin. However, evidence of European introgression into North American aquaculture salmon has accumulated in recent decades, even though the use of diploid European salmon has never been approved in Canada. The full extent of such introgression as well as the potential impacts on wild salmon in the Northwest Atlantic remains uncertain. Here, we extend previous work comparing North American and European wild salmon (n = 5799) using a 220 K SNP array to quantify levels of recent European introgression into samples of domestic salmon, aquaculture escapees, and wild salmon collected throughout Atlantic Canada. Analysis of North American farmed salmon (n = 403) and escapees (n = 289) displayed significantly elevated levels of European ancestry by comparison with wild individuals (p < 0.001). Of North American farmed salmon sampled between 2011 and 2018, ~17% had more than 10% European ancestry and several individuals exceeded 40% European ancestry. Samples of escaped farmed salmon similarly displayed elevated levels of European ancestry, with two individuals classified as 100% European. Analysis of juvenile salmon collected in rivers proximate to aquaculture locations also revealed evidence of elevated European ancestry and larger admixture tract in comparison to individuals collected at distance from aquaculture. Overall, our results demonstrate that even though diploid European salmon have never been approved for use in Canada, individuals of full and partial European ancestry have been in use over the last decade, and that some of these individuals have escaped and hybridized in the wild.

Lignocaine versus opioids in coronary intervention: assessing antiplatelet activity and ticagrelor levels (LOCAL) study

Background

Opioid analgesia impairs the bioavailability and antiplatelet effect of oral P2Y12 inhibitors prompting investigation of mitigation strategies including identifying alternative analgesic agents.

Purpose

To assess the impact of intravenous fentanyl and lignocaine on the bioavailability and antiplatelet effect of ticagrelor in patients with unstable angina and non-ST elevation myocardial infarction, as well as their procedural analgesic efficacy and safety.

Methods

The LOCAL trial was a prospective, single centre, double-blind, randomized, controlled trial where intravenous lignocaine was the experimental analgesic agent assessed in this trial compared to intravenous fentanyl as procedural analgesia during coronary angiography and percutaneous coronary intervention. Patients with an indication for dual antiplatelet therapy and no contraindication were given 180mg of ticagrelor orally as integral tablets with 250 mL of tap water at the end of the case. Blood was sampled at time 0, 0.5, 1, 2 and 4 hours post administration of ticagrelor for pharmacokinetic and comprehensive pharmacodynamic analysis.

Results

Seventy patients undergoing coronary angiography with an indication for ticagrelor loading were included in the pharmacokinetic and pharmacodynamic analysis. Plasma ticagrelor levels at 2 h post loading dose were significantly lower in the fentanyl compared to lignocaine treatment arm (476 vs. 792 ng/mL, p=0.02, see figure 1). The area under the plasma-time curves for ticagrelor (987 vs. 2189 ng.h/mL, p=0.001) and its active metabolite (173 vs. 394 ng.h/mL, p&lt;0.001) were both significantly lower in the fentanyl arm. Platelet reactivity assessed by the VerifyNow assay was higher at all time points after baseline in the fentanyl compared to lignocaine arm. The VASP flow cytometry assay demonstrated higher platelet reactivity at 2 hours in the fentanyl group (40% vs. 22% platelet reactivity index, p=0.001). The Multiplate Analyzer demonstrated higher platelet reactivity in the fentanyl arm at 60 minutes (43 vs. 26 area under the curve units, p=0.001) as did expression of activated platelet GpIIb/IIIa receptor (2829 vs. 1426 geometric mean fluorescence intensity (GMFI), p=0.006) and P-selectin (439 vs. 211 GMFI, p=0.001). High on-treatment platelet reactivity (HPR) was significantly higher in the fentanyl arm at 60 min using the MPA (41% vs. 9%, p=0.002) and 120 min using the VFN (30% vs. 3%, p=0.003) and VASP (37% vs. 6%, p=0.002) assays (see figure 2). Both drugs were well tolerated with a high level of patient satisfaction (fentanyl 94% vs. lignocaine 97%, p=0.56).

Conclusion(s)

Unlike fentanyl, lignocaine does not impair the bioavailability or delay the antiplatelet effect of ticagrelor. Both drugs were well tolerated and effective with a high level of patient satisfaction for procedural analgesia. Systemic pain medication during PCI should be reconsidered and if performed, lignocaine is a beneficial alternative to fentanyl.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): TBA Figure 1. Ticagrelor and AM pharmacokineticsFigure 2. Ticagrelor pharmacodynamics

P–222 Can we optimise the time that we perform the fertilisation check in the lab? Lessons learnt from time-lapse incubation

Study question

Can time-lapse data be used to identify the optimum time to perform the fertilisation check for oocytes cultured in standard incubation?

Summary answer

The optimum time to perform fertilisation checks for oocytes cultured in standard incubation is 16.5hpi+/–0.5h.

What is known already

Time-lapse incubation allows the embryologist to retrospectively review collated images of oocytes and embryos to capture important embryological observations that may have otherwise been missed. This is a luxury not available to embryologists when oocytes or embryos are cultured in standard incubation. Traditionally, the optimum time to perform the fertilisation check is 17 hours post insemination (hpi) +/- 1 hour. It was hypothesised that this could be fine-tuned ensuring the maximum number of fertilised oocytes were observed, thereby increasing the number of usable embryos for the patient.

Study design, size, duration

This was a retrospective, multicentre analysis including data from 27,022 ICSI derived embryos cultured in time-lapse incubation between January 2011 to November 2019.

Participants/materials, setting, methods

The time of pronuclei appearance and disappearance was recorded using the time-lapse incubation software. The number of oocytes exhibiting normal fertilisation (defined as the presence of two pronuclei) during 30 minute intervals from 15hpi to 20hpi was determined.

Main results and the role of chance

Between 15–17.5hpi the average number of oocytes exhibiting normal fertilisation was 98.19% with most oocytes having visible pronuclei at 16–16.5hpi (98.32%). At 18–18.5hpi the number of visible pronuclei falls to 95.53% and continues to fall to 87.02% at 19.5–20hpi meaning that over 3000 (11%) normally fertilised oocytes, within this cohort, would not be identified.

Limitations, reasons for caution

The conclusions of this investigation cannot be effectively extrapolated to IVF embryos as only ICSI embryos were used for the determination of the results.

Wider implications of the findings: The optimum time to perform fertilisation checks for oocytes cultured in standard incubation is 16.5hpi+/–0.5h. However, without the use of time-lapse incubation, the fertilisation of at least 2% of embryos that create a fetal heart will be missed, even if the fertilisation check is performed in the optimum window (16.5hpi+/–0.5h).

Trial registration number

Not applicable

P–792 The introduction of an embryo morphokinetics annotation quality assurance scheme across ten fertility clinics including 59 participants

Study question

Can a group-wide quality assurance scheme be developed to effectively determine inter-operator agreement for morphokinetic parameters of interest.

Summary answer

Very strong agreement was found between all operators except for one, therefore this scheme effectively identified areas of improvement in inter-operator annotations.

What is known already

Where fertility clinics use embryo morphokinetics to determine viability potential, quality assurance of annotations is essential. Embryo selection algorithms rely on the manual determination of certain morphokinetic parameters. Variations in these parameters can lead to differences in the algorithm score attributed to an embryo thus potentially affecting its fate. It is vital that all embryologists involved in embryo annotation and selection are consistent with their annotation approach through regular quality assurance mechanisms.

Study design, size, duration

Each participant was required to annotate the same three embryos for morphokinetic parameters of interest, including tPB2, tPNf, t2 to t5, t8, tM, tSB, tB. Participants were also required to grade embryos at 68 hours post insemination (hpi), 112hpi and to assess additional parameters used for embryo selection or future investigations, such as the extent of morula compaction. The aim of this scheme is to release new distribution each quarter to ensure regular participation.

Participants/materials, setting, methods

All embryologists responsible for embryo annotation in a single, UK fertility group were enrolled onto the scheme. A total of 59 participants from 10 fertility clinics in the UK were included. Inter-operator agreement was assessed using two-way, mixed intraclass correlation coefficient (ICC) for consistency. Five categories of agreement were determined based on ICC score; very weak (0–0.2), weak (0.21–0.4), moderate (0.41–0.6), strong (0.61–0.8) and very strong (0.81–1.0).

Main results and the role of chance

Very strong agreement (0.81–1.0) was observed between all operators for all parameters assessed except for one operator who showed a weak agreement (0.21–0.4) with all other operators. Descriptive statistics revealed standard deviations (SD) ranging from 0.34 (t3) to 3.43 (t5). For each parameter the SD across the three assessed embryos ranged from 0.34–3.43; tPB2 (0.11–0.98), tPNf (2.06–4.40), t2 (0.22–0.80), t3 (0.16–0.70), t4 (0.39–0.65). t5 (2.40–5.44), t8 (0.33–2.72), tM (1.00–2.72), tSB (1.08–2.67), tB (1.12–1.81). These results indicate a high concordance with less subjective annotations such as the cell stage divisions and more variability with the subjective annotations such as the blastulation parameters. The concordance with less well practiced or understood annotations, such as extent of morula compaction, planar or tetrahedral orientation at the four cell stage as well as angle of extrusion of second polar body in relation to the first polar body, was poorer as indicated using descriptive statistics. This highlighted the need for experience in performing these annotations before drawing conclusions regarding their predictive nature in relation to an embryo’s viability.

Limitations, reasons for caution

The variability between more subjective parameters would be expected to be higher than others. The participation in these schemes can create false environments which do not reflect how an embryologist would usually score; they may spend longer on some decisions given the nature of the scheme.

Wider implications of the findings: Quality assurance of morphokinetic annotations across clinics utilising standardised selection models is crucial. Robust annotation policies and education programmes are essential in achieving consistent results between operators. Quality assurance schemes can identify individuals who lack consistency overall and can identify reliably annotated parameters to inform inclusion in embryo selection algorithms.

Trial registration number

Not applicable

P–164 Mulitcentre derived time lapse algorithms developed using 6228 transferred embryos with known birth outcome incorporating novel morphological and morphokinetic markers

Study question

Can incorporation of novel markers of morphology with known temporal events successfully rank embryos to enable prediction of propensity for live birth?

Summary answer

Incorporation of variables for trophectoderm and morula grading demonstrably enhanced the model to rank embryos in order of potential for live birth.

What is known already

Models built using morphokinetic markers of development are widely used to rank embryos within a cohort. Such models include defined temporal parameters which are closely related to morphological grade. However, morphological grading by an embryologist is subjective and is not strongly correlated to outcome. Combining with defined kinetic events has been suggested to improve prediction of outcome.

Study design, size, duration

Data from 6228 known live birth outcome embryos from 8 UK clinics between 2011 – 2018 were investigated using an exploratory approach to identify novel markers of development.

Participants/materials, setting, methods

Five significant variables were defined, a derivative of time to start of blastulation; a derivative of trophectoderm grade; a kinetic variable utilising t3, t4, t5 and t8; an interval variable of tB-tSB and a variable based on novel morula classification. To maximise the output, a proxy value was derived for missing datapoints. The model was built using logistical regression and validated using fivefold cross validation with the data split as 80% training and 20% test.

Main results and the role of chance

An algorithm was developed including the five significant variables identified with an AUC of 0.685 demonstrating reliable prediction of live birth. Without morphological variables, the AUC was 0.674 demonstrating the improvement in the prediction value by including the derivative of the trophectoderm and morula grade. This resulted in ten classes of algorithm scores, 1–10, giving a live birth rate from 2% to 46%, irrespective of patient variables, for chance of live birth.

Limitations, reasons for caution

Successful application of the algorithm is reliant on stringent quality assurance for maintenance of accurate annotation and grading, and may not be transferable between laboratories with different SOPs.

Wider implications of the findings: The addition of a trophectoderm and morula grade in combination with morphokinetic parameters, increases the predictive value of the algorithm in relation to live birth outcome. Using proxy values allows maximization of data for model generation, and allows the model to be applied when missing values are present.

Trial registration number

Not applicable

Risk factors for perioperative blood transfusions after urogenital fistula repair in Uganda: a retrospective cohort study

OBJECTIVE

To determine the incidence of and risk factors for perioperative blood transfusions after urogenital fistula repairs in Uganda.

DESIGN

A retrospective cohort study.

SETTING

A community hospital in Masaka, Uganda.

POPULATION

Women who underwent fistula repair at the Kitovu Hospital between 2013 and 2019.

METHODS

Retrospective review of demographics and clinical perioperative characteristics of patients surgically treated for urogenital fistula. Patient characteristics were compared between those who did and those who did not require a blood transfusion.

MAIN OUTCOME MEASURES

Need for perioperative blood transfusion and risk factors.

RESULTS

A total of 546 patients treated for urogenital fistulas were included in this study. The median age was 31.1 ± 13.2 years. A vaginal surgical approach was used in the majority of patients (84.6%). Complications occurred in 3.5% of surgical repairs, and the incidence of blood transfusions was 6.2%. In multivariable analyses, for each gram per deciliter (g/dl) increase in preoperative haemoglobin, the odds of blood transfusion decreased by approximately 28% (adjusted OR 0.72, 95% CI 0.59-0.86). Women who had their fistula repaired abdominally were 3.4 times more likely to require transfusions (95% CI 1.40-8.08).

CONCLUSIONS

The incidence of blood transfusions among urogenital fistula repairs in our population is twice that of developed nations. An abdominal surgical approach to urogenital fistula is a significant risk factor for perioperative blood transfusions. The timing of the repair may warrant further study.

TWEETABLE ABSTRACT

One of the first studies to look at blood transfusion risk factors after fistula repair in a low-resource setting.

The Barts Health NHS Trust COVID-19 cohort: characteristics, outcomes and risk scoring of patients in East London

BACKGROUND: Barts Health National Health Service Trust (BHNHST) serves a diverse population of 2.5 million people in London, UK. We undertook a health services assessment of factors used to evaluate the risk of severe acute respiratory coronavirus 2 (SARS-CoV-2) infection.METHODS: Patients with confirmed polymerase chain reaction (PCR) test results admitted between 1 March and 1 August 2020 were included, alongwith clinician-diagnosed suspected cases. Prognostic factors from the 4C Mortality score and 4C Deterioration scores were extracted from electronic health records and logistic regression was used to quantify the strength of association with 28-day mortality and clinical deterioration using national death registry linkage.RESULTS: Of 2783 patients, 1621 had a confirmed diagnosis, of whom 61% were male and 54% were from Black and Minority Ethnic groups; 26% died within 28 days of admission. Mortality was strongly associated with older age. The 4C mortality score had good stratification of risk with a calibration slope of 1.14 (95% CI 1.01-1.27). It may have under-estimated mortality risk in those with a high respiratory rate or requiring oxygen.CONCLUSION: Patients in this diverse patient cohort had similar mortality associated with prognostic factors to the 4C score derivation sample, but survival might be poorer in those with respiratory failure.

Applicability assessment of a stent-retriever thrombectomy finite-element model

An acute ischaemic stroke appears when a blood clot blocks the blood flow in a cerebral artery. Intra-arterial thrombectomy, a mini-invasive procedure based on stent technology, is a mechanical available treatment to extract the clot and restore the blood circulation. After stent deployment, the clot, trapped in the stent struts, is pulled along with the stent towards a receiving catheter. Recent clinical trials have confirmed the effectiveness and safety of mechanical thrombectomy. However, the procedure requires further investigation. The aim of this study is the development of a numerical finite-element-based model of the thrombectomy procedure. In vitro thrombectomy tests are performed in different vessel geometries and one simulation for each test is carried out to verify the accuracy and reliability of the proposed numerical model. The results of the simulations confirm the efficacy of the model to replicate all the experimental setups. Clot stress and strain fields from the numerical analysis, which vary depending on the geometric features of the vessel, could be used to evaluate the possible fragmentation of the clot during the procedure. The proposed in vitro/in silico comparison aims at assessing the applicability of the numerical model and at providing validation evidence for the specific in vivo thrombectomy outcomes prediction.

0669 The Effects Of Continuous Positive Airway Pressure Therapy In Moderate To Severe Obstructive Sleep Apnea: A High-density EEG Study

Introduction

A previous high-density electroencephalography (EEG) investigation in asymptomatic OSA showed regional deficits in sleep EEG power particularly slow wave activity (SWA) during NREM sleep in the parietal region. It is unclear whether treatment with CPAP can reverse local sleep EEG abnormalities in OSA, and whether any recovery is related to improvement in sleep-dependent memory consolidation.

Methods

Fifteen male participants (age 50.4±6.5yrs, AHI 51.7±23.5/h) with moderate-severe OSA (AHI&gt;15/h) underwent overnight polysomnography with 256-channel high-density EEG at baseline and following 3 months of CPAP therapy. A word paired associates declarative memory task was administered before and after sleep. After artefact removal, spectral analysis was performed for all channels. Topographical power maps were calculated for standard frequency ranges for NREM sleep (164 channels within a 0.57 radius from the vertex). Maps were compared using both absolute and normalized power (z-scores computed for each subject) and differences between baseline and treatment were determined by statistical nonparametric mapping.

Results

In 11 CPAP compliant patients (intolerant of CPAP [n=3]/high-density EEG [n=1]), analysis of polysomnographic variables showed that total sleep time did not differ but N1 (baseline vs. treatment: 66.9 vs. 39.5 mins,p=0.008) and N2 (195.0 vs. 150.6 mins,p=0.002) sleep was lower and N3 (89.8 vs. 128.7 mins,p=0.003) was higher after CPAP. Topographic analysis of high-density EEG data revealed a regional increase in SWA (1-4.5Hz) EEG power during N3 sleep in a cluster of electrodes overlying the centro-parietal cortex (cluster mean t-value=2.87,p=0.02). The change in overnight declarative memory consolidation (% recognition) after CPAP was significantly correlated with the change in slow spindle frequency activity in frontal regions (cluster mean r=0.875,p=0.003).

Conclusion

CPAP treatment may enhance localised deficits in sleep EEG activity in OSA, and specific regional recovery may translate to memory improvements in the short-term. These data also highlight the potential for long-term therapeutic effects on cognitive outcomes in OSA.

Support