A comprehensive, contemporary assessment of the association between hepatosteatosis and coronary artery calcium scoring

Funding Acknowledgements

Type of funding sources: None.

onbehalf

Liverpool Multiparametric Imaging Collaboration

Background

Coronary artery calcium (CAC) score is a well-established technique for stratifying an individual’s cardiovascular disease (CVD) risk. Several well-established registries have incorporated CAC scoring into CVD risk prediction models to enhance accuracy. Hepatosteatosis (HS) has been shown to be an independent predictor of CVD events and can be measured on non-contrast computed tomography (CT). We sought to undertake a contemporary, comprehensive assessment of the influence of HS on CAC score alongside traditional CVD risk factors. In patients with HS it may be beneficial to offer routine CAC screening to evaluate CVD risk to enhance opportunities for earlier primary prevention strategies.

Methods

We performed a retrospective, observational analysis at a high-volume cardiac CT centre analysing consecutive CT coronary angiography (CTCA) studies. All patients referred for investigation of chest pain over a 28-month period (June 2014 to November 2016) were included. Patients with established CVD were excluded. The cardiac findings were reported by a cardiologist and retrospectively analysed by two independent radiologists for the presence of HS. Those with CAC of zero and those with CAC greater than zero were compared for demographic and cardiac risks. A multivariate analysis comparing the risk factors was performed to adjust for the presence of established risk factors. A binomial logistic regression model was developed to assess the association between the presence of HS and increasing strata of CAC.

Results

In total there were 1499 patients referred for CTCA without prior evidence of CVD. The assessment of HS was completed in 1195 (79.7%) and CAC score was performed in 1103 (92.3%). There were 466 with CVD and 637 without CVD. The prevalence of HS was significantly higher in those with CVD versus those without CVD on CTCA (51.3% versus 39.9%, p = 0.007). Male sex (50.7% versus 36.1% p= <0.001), age (59.4 ± 13.7 versus 48.1 ± 13.6, p= <0.001) and diabetes (12.4% versus 6.9%, p = 0.04) were also significantly higher in the CAC group compared to the CAC score of zero.

HS was associated with increasing strata of CAC score compared with CAC of zero (CAC score 1-100 OR1.47, p = 0.01, CAC score 101-400 OR:1.68, p = 0.02, CAC score >400 OR 1.42, p = 0.14). This association became non-significant in the highest strata of CAC score.

Conclusion

We found a significant association between the increasing age, male sex, diabetes and HS with the presence of CAC. HS was also associated with a more severe phenotype of CVD based on the multinomial logistic regression model. Although the association reduced for the highest strata of CAC (CAC score >400) this likely reflects the overall low numbers of patients within this group and is likely a type II error.

Based on these findings it may be appropriate to offer routine CVD risk stratification techniques in all those diagnosed with HS.

Modified HEART score, utilising a single high-sensitive troponin sample, allows early, safe discharge of suspected acute coronary syndrome: a prospective multicentre cohort study of 3016 patients

Background

Combining HSTnT (high sensitive troponin T) values at low levels with composite risk scores may improve early safe, discharge in suspected acute coronary syndromes (ACS). We tested this hypothesis by a prospective study of 3016 consecutive patients with suspected ACS in 2 large hospitals.

Methods

Consecutive chest pain (CP) presentations with HSTnT sampled and ECG undertaken at presentation were prospectively defined in 2 time periods (2011-12, n=1642 [derivation] 2018, n=1376 [validation]).

The HstnT input was modified: dichotomous HSTnT input was lowered to <5 (limit of detection, LOD) or ≥5ng/l (mod TIMI and GRACE), HEART score was re-calibrated (<5 = 0 [LOD], ≥5–14 = 1, >14 = 2 [99th percentile]). All biomarker positive CP index and re-admissions to any regional hospital (catchment population 2.6 million) were independently adjudicated for MI by 2 experienced physicians. Primary outcome was MACE (adjudicated type 1 MI, unplanned coronary revascularisation and all cause death) at 6 weeks.

Results

In the 2 cohorts demographic factors were similar: median age 59 and 56, male 52% and 52%, previous MI 20% and 14% for 2011-12 and 2018 respectively. At 6 weeks 180 (11%) and 75 (5.4%) suffered type 1 MI and 211 (12.9%) and 92 (6.7%) patients suffered MACE in the 2011-12 and 2018 cohorts respectively.

Only Mod HEART ≤3 and undetectable HSTnT, with a nonischaemic ECG, achieved prespecified NPV of >99.5% in both derivation and validation cohorts (table). However Modified HEART ≤3 score could discharge approximately 12% more patients as compared to undetectable HSTnT strategy.

Conclusion

Modified HEART score ≤3, with the use of a single HSTnT, appears the optimum early discharge strategy for suspected ACS

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Liverpool university Hospitals, North-West Educational Cardiac Group

Slower recovery of outpatient clinics than inpatient services for stroke and other neurological diseases after COVID-19 Pandemic

Background

In this brief report, we investigated the impact of COVID‐19 on outpatient stroke clinics and inpatient services and their recovery process.

Methods

We sent a survey to physicians worldwide through the network of the World Stroke Organization to investigate the impact of COVID‐19 on stroke clinics. To farther along in recovering from the outbreak, we reviewed stroke and other neurology outpatient clinic visits (approximately 50% were stroke related) and the number of inpatient services from December 2019 to July 2020 in a large neurology department in Shanghai, China, where there was no official city lockdown.

Results

We received 112 valid survey responses from 46 countries, representing all continents except for Antarctica. Only seven of the survey responders (7/112, 6.3%) reported that they have kept their outpatient clinics open as usual, but they did exercise increased precautions for COVID‐19 by following recent guidelines regarding use of personal protective equipment and isolation techniques. The remainder of the respondents have either reduced outpatient clinic services or suspended outpatient clinics completely. Telephone consultation or telemedicine with video capability was used for new patients or follow‐ups, with limited in‐person evaluations when necessary. Outpatient clinic visits and inpatient services from a large tertiary hospital in China decreased dramatically during the peak period of the outbreak, but then rebounded back quickly following the partial or full recovery from the outbreak. Compared with the recovery process of inpatient services, outpatient clinic visits decreased faster and recovered much slower. This is consistent with our global survey data which indicates that some outpatient clinics have rescheduled their outpatient visits for 3 to 6 months.

Conclusions

The COVID‐19 pandemic caused a significant drop of in‐person outpatient visits and inpatient services. Clinic visits recovered slower than inpatient services in stroke and other neurological diseases after the pandemic.

Challenging the Ischemic Core Concept in Acute Ischemic Stroke Imaging

Endovascular treatment is a highly effective therapy for acute ischemic stroke due to large vessel occlusion and has recently revolutionized stroke care. Oftentimes, ischemic core extent on baseline imaging is used to determine endovascular treatment-eligibility. There are, however, 3 fundamental issues with the core concept: First, computed tomography and magnetic resonance imaging, which are mostly used in the acute stroke setting, are not able to precisely determine whether and to what extent brain tissue is infarcted (core) or still viable, due to variability in tissue vulnerability, the phenomenon of selective neuronal loss and lack of a reliable gold standard. Second, treatment decision-making in acute stroke is multifactorial, and as such, the relative importance of single variables, including imaging factors, is reduced. Third, there are often discrepancies between core volume and clinical outcome. This review will address the uncertainty in terminology and proposes a direction towards more clarity. This theoretical exercise needs empirical data that clarify the definitions further and prove its value.

Gaining political will for actions to achieve health equity: lessons from Australia for advocates

Background

There has been an accumulation of evidence on the importance of action on the social determinants of health to reduce global and national health equity. Yet there has been little effective systematic action by governments. This is commonly attributed to the absence of political will. Despite its importance, however, little research has examined how political will might be created or prevented.

Methods

This paper reports on the results of eight case studies of the extent to which Australian public policy is likely to contribute to reducing health inequities. 192 participants were interviewed including public servants, politicians and their staff, non-government organisation workers and community members. The transcripts were interrogated with the assistance of NVivo software to determine lessons about the creation or destruction of political will. The case studies were of: national primary health care policy, crucial determinants of health (work conditions, internet access, urban planning, social welfare, trade) and an automotive plant closure.

Results

We found the following factors to be important in determining the extent of political will for health equity, whether: path dependency was present; the issue would impact on staying in or winning government; political philosophies stressed collectivism or individualism; there were negative or positive social constructions of groups affected by the policies; economic and/or biomedical framings were dominant; elites (especially business interests) lobbied against the policies; and there was effective civil society and policy advocacy in favour of the policies.

Conclusions

Building on our insights from our case studies of action for political will, we conclude with a series of questions to guide the work of public health activists and policy advocates working to support existing and to create new political will in multiple contexts.

Key messages

The creation of political will is vital to the adoption of policies supportive of health equity. Analysis of 8 policy case studies points to how advocacy can most effectively create political will.

How can corporate HIA help shape regulatory environments for Trans-National Corporations?

Background

Transnational Corporations (TNCs) exercise considerable sway over population health. They now comprise 157 of the 200 largest economies in the world and shape our food choices and degree of exploitation of our natural environment. This paper will analyse data from two corporate health impact assessments exercise (food and extractive industries) to determine what government and international agency regulatory actions are required to minimize the health harm causes by the actions of TNCs.

Methods

We used a Corporate Health Impact Assessment (CHIA) framework, data sourced through document and media analyses, and semi-structured interviews to examine the practices of McDonalds in Australia and Rio Tinto in Australia and South Africa. Data were mapped against the CHIA framework's three sections which are: i) the impact of regulatory environments ii) How TNC practices and products impact on health and equity ii) the direct impact of TNCs practices on daily living conditions.

Results

The CHIA exercise indicated an absence of effective international regulation on the actions of TNCs and that national regulatory regimes can encourage more responsible behavior from TNCs, for example in occupational health and safety. We identified the need for a much higher level of global and national regulation to: i) prevent the many conflicts of interest we found ii) reduce the extent to which TNC products are unhealthy iii) enforce healthy employment practices iv) prevent externalization of the costs of TNCs v) prevent taxation minimization.

Conclusions

The study highlighted the ways in which TNCs can use their power and size to maintain a de-regulated environment. Concerted global and national action is required to regulate in favour of human health and safety and that of the environment. Our findings support the need for an enforceable international treaty.

Key messages

Transnational corporations have a massive impact on population health. A health impact assessment can identify the pathways of impact and be used to inform regulatory action to promote health.

Changes in Anticoagulant Utilization Among United States Nursing Home Residents With Atrial Fibrillation From 2011 to 2016

Background

Nursing home residents with atrial fibrillation are at high risk for ischemic stroke and bleeding events. The most recent national estimate (2004) indicated less than one third of this high‐risk population was anticoagulated. Whether direct‐acting oral anticoagulant (DOAC) use has disseminated into nursing homes and increased anticoagulant use is unknown.

Methods and Results

A repeated cross‐sectional design was used to estimate the point prevalence of oral anticoagulant use on July 1 and December 31 of calendar years 2011 to 2016 among Medicare fee‐for‐service beneficiaries with atrial fibrillation residing in long‐stay nursing homes. Nursing home residence was determined using Minimum Data Set 3.0 records. Medicare Part D claims for apixaban, dabigatran, edoxaban, rivaroxaban, and warfarin were identified and point prevalence was estimated by determining if the supply from the most recent dispensing covered each point prevalence date. A Cochran‐Armitage test was performed for linear trend in prevalence. On December 31, 2011, 42.3% of 33 959 residents (median age: 85; Q1 79, Q3 90) were treated with an oral anticoagulant, of whom 8.6% used DOACs. The proportion receiving treatment increased to 47.8% of 37 787 residents as of December 31, 2016 (P<0.01); 48.2% of 18 054 treated residents received DOACs. Demographic and clinical characteristics of residents using DOACs and warfarin were similar in 2016. Half of the 8734 DOAC users received standard dosages and most were treated with apixaban (54.4%) or rivaroxaban (35.8%) in 2016.

Conclusions

Increases in anticoagulant use among US nursing home residents with atrial fibrillation coincided with declining warfarin use and increasing DOAC use.

Comparative Safety and Effectiveness of Direct-Acting Oral Anticoagulants Versus Warfarin: a National Cohort Study of Nursing Home Residents

BACKGROUND

Research comparing direct-acting oral anticoagulants (DOACs) to warfarin has excluded nursing home residents, a vulnerable and high-risk population.

OBJECTIVE

To compare the safety and effectiveness of DOACs versus warfarin.

DESIGN

New-user cohort study (2011-2016).

PATIENTS

US nursing home residents aged > 65 years with non-valvular atrial fibrillation enrolled in fee-for-service Medicare for > 6 months.

EXPOSURES

Initiators of DOACs (2881 apixaban, 1289 dabigatran, 3735 rivaroxaban) were 1:1 propensity matched to warfarin initiators.

MAIN MEASURES

Outcomes included ischemic stroke or transient ischemic attack (i.e., ischemic cerebrovascular event), bleeding (extracranial or intracranial), other vascular events, death, and a composite of all outcomes. Absolute rate differences (RD) and cause-specific hazard ratios (HR) with 95% confidence intervals (CI) were estimated. Subgroup analyses were performed by alignment of DOAC dosing with labeling.

KEY RESULTS

Median age (84 years), CHA₂DS₂-Vasc (5), and ATRIA risk scores (3) were similar across medications. Clinical outcome rates were similar for dabigatran and rivaroxaban users versus warfarin users. However, ischemic cerebrovascular event rates were higher among dabigatran and rivaroxaban users that received reduced dosages without an indication. Overall, apixaban users had higher ischemic cerebrovascular event rates (HR 1.86; 95% CI 1.00-3.45) and lower bleeding rates (HR 0.66; 95% CI 0.49-0.88), but outcome rates varied by dosing alignment. Mortality rates (per 100 person-years) were lower for apixaban (RDs - 9.30; 95% CI - 13.18 to - 5.42), dabigatran (RDs - 10.79; 95% CI - 14.98 to - 6.60), and rivaroxaban (RDs - 8.92; 95% CI - 12.01 to - 5.83) versus warfarin; composite outcome findings were similar.

CONCLUSIONS

Among US nursing home residents, the DOACs were each associated with lower mortality versus warfarin. Misaligned DOAC dosing was common in nursing homes and was associated with clinical and mortality outcomes. Overall, DOAC users had lower rates of adverse outcomes including mortality compared with warfarin users.

Embolic Stroke of Undetermined Source: Gateway to a New Stroke Entity?

Embolic stroke of unknown source (ESUS) is currently thought to represent a subpopulation of cryptogenic strokes defined by its embolic stroke pattern on imaging, and if after a carefully performed diagnostic evaluation, a specific, well-recognized cause of stroke has not been identified. The concept was primarily established to justify and enable the conduct of the ESUS trials, such as Randomized, Double-Blind, Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate versus Acetylsalicylic Acid in Patients with Embolic Stroke of Undetermined Source (RESPECT-ESUS) and New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial versus aspirin to Prevent Embolism in Embolic Stroke of Undetermined Source (NAVIGATE-ESUS). With both studies having neutral results, the question arises if the ESUS concept is misleading or rather a gateway for a modern understanding of stroke etiology. This review will analyze the background of the ESUS concept, overview the results and the impact of the recent multicenter trials and cohort studies, and discuss the definition, etiology, and diagnosis of ESUS.

1004 Smith-&lt;Magenis Syndrome (SMS) Circadian Abnormalities And Biological Rhythms

Introduction

SMS is a rare neurodevelopmental disorder that manifests with craniofacial abnormalities, behavioral disturbances, and a severe sleep disorder. It has been reported that many SMS patients have an inverted melatonin secretion pattern (peaking during the daytime) although a small minority have near normal patterns. The goal of this study was to better characterize the intra- and inter-patient variability of melatonin secretion patterns and investigate a potential relationship with sleep behavior in SMS patients.

Methods

In this observational study, sleep behaviors of patients (N=8, 1 female, ages: 7 - 35) with SMS were characterized through caretaker surveys. On 3 separate occasions, patients had hourly serum melatonin levels sampled for 36 hours. From these data, peak serum melatonin concentration and time of peak concentration were determined. Inter- and intra-patient variability was characterized by zero lag correlation of the melatonin concentration timeseries across and within patients, respectively. The relationship between peak melatonin concentration, peak time, and sleep latency was analyzed by a generalized linear model, GLM.

Results

Peak melatonin concentrations varied across SMS patients with a range of 3.55pg/ml - 49.65pg/ml (mean 14.18 ± 15.19pg/ml). Time of peak melatonin concentrations ranged from 0400h-2100h (mean 1422 ± 6h). Correlation coefficients characterizing intra-patient variability ranged from -0.0098 to 0.89 (mean 0.55 ± 0.2533). Correlation coefficients characterizing inter-patient variability ranged from -0.75 to 0.79 (mean of 0.18 ± 0.52). Sleep latency ranged from 8.4min - 36.35min (mean of 21.99 ± 9.77 min). GLM analysis demonstrated a significant, positive effect of peak time with sleep latency (p=0.022).

Conclusion

Consistent with previous findings, our study confirms that SMS patients have abnormal circadian rhythms. Our work extends this body of literature by demonstrating a significant degree of inter-patient variability with relatively stable intra-patient variability. Preliminary evidence suggests that the timing of melatonin peak may be related to sleep onset latency.

Support

This work was supported by Vanda Pharmaceuticals Inc.

1161 Tasimelteon Shows Persistence Of Efficacy In Improving Sleep Disturbances In Patients With Smith-Magenis Syndrome (SMS) In Open-Label Extension Study

Introduction

Smith-Magenis Syndrome (SMS) is a rare (1/15,000 - 25,000 births) neurodevelopmental disorder resulting from an interstitial deletion of chromosome 17p11.2, or from a point mutation in the RAI1 gene. Severe sleep disorder is almost universal in patients with SMS and poses a significant challenge to patients and their families. Tasimelteon improved sleep symptoms in a randomized, double-blind, two-period, crossover study; and here we show that this effect persists for up to four years in an open-label extension. To our knowledge, this is the largest interventional study of SMS patients to date.

Methods

Following the 4-week crossover study, all eligible participants had the option to enroll in an open-label extension. 31/39 (79.4%) of all individuals who participated in the efficacy study have continued on tasimelteon treatment. Participants in the open-label extension provided daily diary sleep quality (DDSQ), and daily diary total sleep time (DDTST) measures via parental post sleep questionnaire and characterized behavior using the Aberrant Behavior Checklist (ABC).

Results

In the open-label extension, tasimelteon continued to show improvement in the primary endpoints of 50% worst sleep quality (mean = 0.7, SD = 0.94) and 50% worst total nighttime sleep duration (mean = 53.3, SD = 59.01) when compared to baseline. Tasimelteon also improved overall sleep quality (mean=0.7, SD=0.83) and overall total nighttime sleep duration (mean = 51.9, SD=53.03). ABC scores also improved with tasimelteon (mean= -16.3, SD = 15.82).

Conclusion

Tasimelteon continues to demonstrate persistence in efficacy (longest approximately 4 years) with similar magnitudes observed in the 4-week crossover study for sleep quality and total sleep time. Interestingly, daytime behavior also demonstrates long-term improvement in patients with SMS treated with tasimelteon. These results further confirm tasimelteon as a novel therapy for the treatment of sleep disorders in patients with SMS and may provide benefit for behavioral symptoms.

Support

This work was supported by Vanda Pharmaceuticals Inc.

Impact of the COVID-19 Epidemic on Stroke Care and Potential Solutions

BACKGROUND AND PURPOSE

When the coronavirus disease 2019 (COVID-19) outbreak became paramount, medical care for other devastating diseases was negatively impacted. In this study, we investigated the impact of the COVID-19 outbreak on stroke care across China.

METHODS

Data from the Big Data Observatory Platform for Stroke of China consisting of 280 hospitals across China demonstrated a significant drop in the number of cases of thrombolysis and thrombectomy. We designed a survey to investigate the major changes during the COVID-19 outbreak and potential causes of these changes. The survey was distributed to the leaders of stroke centers in these 280 hospitals.

RESULTS

From the data of Big Data Observatory Platform for Stroke of China, the total number of thrombolysis and thrombectomy cases dropped 26.7% (P<0.0001) and 25.3% (P<0.0001), respectively, in February 2020 as compared with February 2019. We retrieved 227 valid complete datasets from the 280 stroke centers. Nearly 50% of these hospitals were designated hospitals for COVID-19. The capacity for stroke care was reduced in the majority of the hospitals. Most of the stroke centers stopped or reduced their efforts in stroke education for the public. Hospital admissions related to stroke dropped ≈40%; thrombolysis and thrombectomy cases dropped ≈25%, which is similar to the results from the Big Data Observatory Platform for Stroke of China as compared with the same period in 2019. Many factors contributed to the reduced admissions and prehospital delays; lack of stroke knowledge and proper transportation were significant limiting factors. Patients not coming to the hospital for fear of virus infection was also a likely key factor.

CONCLUSIONS

The COVID-19 outbreak impacted stroke care significantly in China, including prehospital and in-hospital care, resulting in a significant drop in admissions, thrombolysis, and thrombectomy. Although many factors contributed, patients not coming to the hospital was probably the major limiting factor. Recommendations based on the data are provided.

Involving Service Users in Professional Nurse Education in Wales

A small scale survey was conducted among nurse educationalists within Wales as part of the ongoing monitoring of Welsh Office targets for learning disability nursing. This survey showed that there has been very little service user involvement in professional nurse education in Wales. The authors discuss the possible reasons for such low level involvement. Examples of involvement of people with learning disabilities are compared to the much more favourable situation within the mental health field. Possible reasons for the barriers to progress in this area are discussed. The history of service user involvement and the development of advocacy both within the UK and other countries is also highlighted. The impact of various government initiatives on this situation is considered.

Neuroprotective Effects of Selective Inhibition of Histone Deacetylase 3 in Experimental Stroke

Histone deacetylase 3 (HDAC3) has been implicated as neurotoxic in several neurodegenerative conditions. However, the role of HDAC3 in ischemic stroke has not been thoroughly explored. We tested the hypothesis that selective inhibition of HDAC3 after stroke affords neuroprotection. Adult male Wistar rats (n = 8/group) were subjected to 2 h of middle cerebral artery occlusion (MCAO), and randomly selected animals were treated intraperitoneally twice with either vehicle (1% Tween 80) or a selective HDAC3 inhibitor (RGFP966, 10 mg/kg) at 2 and 24 h after MCAO. Long-term behavioral tests were performed up to 28 days after MCAO. Another set of rats (n = 7/group) were sacrificed at 3 days for histological analysis. Immunostaining for HDAC3, acetyl-Histone 3 (AcH3), NeuN, TNF-alpha, toll-like receptor 4 (TLR4), cleaved caspase-3, cleaved poly (ADP-ribose) polymerase (PARP), Akt, and TUNEL were performed. Selective HDAC3 inhibition improved long-term functional outcome (p < 0.05) and reduced infarct volume (p < 0.0001). HDAC3 inhibition increased levels of AcH3 in the ischemic brain (p = 0.016). Higher levels of AcH3 were significantly correlated with better neurological scores and smaller infarct volumes (r = 0.74, p = 0.002; r = 0.6, p = 0.02, respectively). The RGFP966 treatment reduced apoptosis-TUNEL+, cleaved caspase-3+, and cleaved PARP+ cells-and neuroinflammation-TNF-alpha+ and TLR4+ cells-in the ischemic border compared to vehicle control (p < 0.05). The RGFP966 treatment also increased Akt expression in the ipsilateral cortex (p < 0.001). Selective HDAC3 inhibition after stroke improves long-term neurological outcome and decreases infarct volume. The neuroprotective effects of HDAC3 inhibition are associated with a reduction in apoptosis and inflammation and upregulation of the Akt pathway.

A review of the NG17 recommendations for the use of basal insulin in type 1 diabetes

AIMS

To revisit the data analysis used to inform National Institute of Health and Care Excellence (NICE) NG17 guidance for initiating basal insulin in adults with type 1 diabetes mellitus (diabetes).

METHODS

We replicated the data, methodology and analysis used by NICE diabetes in the NG17 network meta-analysis (NMA). We expanded this data cohort to a more contemporary data set (extended 2017 NMA) and restricted the studies included to improve the robustness of the data set (restricted 2017 NMA) and in a post hoc analysis, changed the index comparator from neutral protamine Hagedorn (NPH) insulin twice daily to insulin detemir twice daily.

RESULTS

The absolute changes in HbA_1c were similar to those reported in the NG17. However, all 95% credible intervals for change in HbA_1c point estimates crossed the line of null effect, except for detemir twice daily (in the NICE and extended 2017 NMAs) and NPH four times daily. In the detemir twice-daily centred post hoc analysis, the 95% credible intervals for change in HbA_1c crossed the line of null effect for all basal therapies, except NPH.

CONCLUSIONS

In NG17, comparisons of basal insulins were based solely on efficacy of glycaemic control. Many of the trials used in this analysis were treat-to-target, which minimize differences in HbA_1c . In the NMAs, statistical significance was severely undermined by the wide credible intervals. Despite these limitations, point estimates of HbA_1c were used to rank the insulins and formed the basis of NG17 guidance. This study queries whether such analyses should be used to make specific clinical recommendations.

Abstract TP272: Selective Inhibition of Histone Deacetylase 3 Decreases Cerebral Edema and Blood-Brain Barrier Leakage

Introduction: Histone deacetylase 3 (HDAC3) has been implicated as neurotoxic in several neurodegenerative conditions. However, its role in ischemic stroke has not been thoroughly explored. In this study, we examined HDAC3 expression after stroke and tested whether selective inhibition of HDAC3 decreases cerebral edema and blood-brain barrier (BBB) leakage after ischemia.

Methods: To examine HDAC3 expression over time, adult male Wistar rats (n=6/group) were subjected to middle cerebral artery occlusion (MCAO) and sacrificed at different time points after stroke. Another set of adult male Wistar rats was subjected to 2-h MCAO, and randomly selected animals were treated i.p. with either vehicle (1% Tween 80) or a selective HDAC3 inhibitor (RGFP966, 10 mg/kg) at 2 and 24 h after MCAO. Behavioral tests were performed, and infarct volumes and cerebral edema were measured. Evans blue dye (EBD) assay was employed to assess BBB leakage. Immunostaining for HDAC3, CD31, claudin-5, occludin, and ZO-1; and Western Blot for TNF-alpha and matrix metalloproteinase-9 (MMP9) were performed.

Results: Total and neuronal HDAC3 significantly increased in the peri-infarct cortex as early as 3 hours after ischemia. HDAC3 levels continued to be significantly elevated at 3 days and returned to baseline at 7 days. Selective HDAC3 inhibition improved functional outcome (p=0.01) and reduced infarct volumes (p<0.001). Compared to vehicle control, RGFP966 treatment significantly decreased cerebral edema (p<0.001) as well as BBB leakage, as measured by EBD assay. Immunostaining showed that RGFP966 significantly increased the expression of tight junction proteins (claudin-5, occludin, and ZO-1) in the peri-infarct area compared to vehicle control group. Western Blot showed that RGFP966 treatment significantly decreased the expression of TNF-alpha and MMP9 in the ischemic brain.

Conclusions: HDAC3 is upregulated in the ischemic brain as early as 3 hours after stroke. Early administration of a selective HDAC3 inhibitor improves neurological functional outcome and decreases infarct volume, cerebral edema, and BBB leakage. BBB protection by selective inhibition of HDAC3 is mediated in part by upregulation of tight junction proteins and attenuation of TNF-alpha and MMP9.

Electro-acupuncture inhibits C-fiber-evoked WDR neuronal activity of the trigeminocervical complex: Neurophysiological hypothesis of a complementary therapy for acute migraine modeled rats

INTRODUCTION

Acupuncture has become a relevant complementary and alternative treatment for acute migraine; however, the neurophysiological mechanism (C-fibers) underlying this effect remains unclear. C-fibers play a crucial role for diffuse noxious inhibitory controls (DNIC) at wide dynamic range (WDR) neurons in the trigeminocervical complex (TCC) in migraine attacks, and we supposed that this may be the mechanism of acupuncture analgesia. This study aimed to examine the neurophysiology of acupuncture intervention in an acute migraine rat model.

METHODS

Inflammatory soup (IS) or saline was injected into the dura mater to establish a migraine and control model in rats. To explore the neurobiological mechanism of acupuncture for migraine, we implemented electro-acupuncture (EA), non-electric-stimulation acupuncture, and no-acupuncture in IS and saline injected rats, and recorded the single-cell extraneural neurophysiology of the atlas (C1) spinal dorsal horn neurons in the TCC.

RESULTS

Our research shows that electro-acupuncture at GB8 (Shuaigu), located in the periorbital region receptive field of the trigeminal nerve, may rapidly reduce the C-fiber evoked WDR neuronal discharges of the TCC within 60 s.

DISCUSSION

This study provides pioneering evidence of a potential neurobiological mechanism for the analgesic effect on migraine attacks achieved by electro-acupuncture intervention via DNIC. The data indicates that EA may become a crucial supplementary and alternative therapy for migraineurs that failed to respond to acute medications, e.g., fremanezumab, which achieves its analgesic effect via modulating Aσ-fibers, not C-fibers.

Prophylactic Electroacupuncture on the Upper Cervical Segments Decreases Neuronal Discharges of the Trigeminocervical Complex in Migraine-Affected Rats: An in vivo Extracellular Electrophysiological Experiment

Purpose

This rat experiment aims to demonstrate the efficacy of electrical acupuncture in preventing migraine attacks by stimulating the acupoint GB20.

Introduction

Migraine, which takes 2ed at level four causes of GBD’s disease hierarchy, becomes a public health issue. It is important for physicians to supplement their knowledge of its treatment and consider alternative methods of therapy, such as acupuncture. However, the neurobiological and pathophysiological mechanisms of this prophylactic effect were unclear. The trigeminocervical complex is thought to be an important relay station in migraine pathophysiology as the key nuclei of the trigeminovascular system and the brainstem descending pain modulation system.

Methods

There were six groups involved in this study: control, model, electroacupuncture, non-acupoint electroacupuncture, saline+electroacupuncture and saline+non-acupoint electroacupuncture. We injected saline or inflammatory soup into dura mater to induce control or migraine in the rats. The mechanical pain threshold and the single-cell extraneural neurophysiology of the C1 spinal dorsal horn neurons in the trigeminocervical complex were detected.

Results

Pre-electroacupuncture could significantly increase the mechanical pain threshold of the periorbital region receptive field of the trigeminal nerve and decrease the discharges of neurons in the trigeminocervical complex. Acupuncture also reversed the abnormal skin pain response of the periorbital region receptive field of the trigeminal nerve caused by low-intensity stimulation.

Discussion

We believe that our study makes a significant contribution to the literature because it is the first of its kind to use GB20 to provide relief from migraine attacks and mechanical cephalic cutaneous hypersensitivity by regulating the neuronal discharge from trigeminocervical complex.

TRIAGE-STROKE: Treatment strategy In Acute larGE vessel occlusion: Prioritize IV or endovascular treatment-A randomized trial

RATIONALE

For patients with acute ischemic stroke and large vessel occlusions, intravenous thrombolysis and endovascular therapy are standard of care, but the effect of endovascular therapy is superior to intravenous thrombolysis. If a severe stroke with symptoms indicating large vessel occlusions occurs in the catchment area of a primary stroke center, there is equipoise regarding optimal transport strategy.

AIM

For patients presenting with suspected large vessel occlusions (PASS ≥ 2) and a final diagnosis of acute ischemic stroke, we hypothesize that bypassing the primary stroke center will result in an improved 90-day functional outcome.

SAMPLE SIZE

We aim to randomize 600 patients, 1:1.

DESIGN

A national investigator-driven, multi-center, randomized assessor-blinded clinical trial. The Prehospital Acute Stroke Severity Scale has been developed. It identifies most patients with large vessel occlusions in the pre-hospital setting. Patients without a contraindication for intravenous thrombolysis are randomized to either transport directly to a comprehensive stroke centers for intravenous thrombolysis and of endovascular therapy or to a primary stroke center for intravenous thrombolysis and subsequent transport to a comprehensive stroke centers for of endovascular therapy, if needed.

OUTCOMES

The primary outcome will be the 90-day modified Rankin Scale score (mRS) for all patients with acute ischemic stroke. Secondary outcomes include 90-day mRS for all randomized patients, all patients with ischemic stroke but without large vessel occlusions, and patients with hemorrhagic stroke. The safety outcomes include severe dependency or death and time to intravenous thrombolysis for ischemic stroke patients.

DISCUSSION

Study results will influence decision making regarding transport strategy for patients with suspected large vessel occlusions.

Identifying critical source areas using multiple methods for effective diffuse pollution mitigation

Diffuse pollution from agriculture constitutes a key pressure on the water quality of freshwaters and is frequently the cause of ecological degradation. The problem of diffuse pollution can be conceptualised with a source-mobilisation-pathway (or delivery)-impact model, whereby the combination of high source risk and strong connected pathways leads to 'critical source areas' (CSAs). These areas are where most diffuse pollution will originate, and hence are the optimal places to implement mitigation measures. However, identifying the locations of these areas is a key problem across different spatial scales within catchments. A number of approaches are frequently used for this assessment, although comparisons of these assessments are rarely carried out. We evaluate the CSAs identified via traditional walkover surveys supported by three different approaches, highlighting their benefits and disadvantages. These include a custom designed smartphone app; a desktop geographic information system (GIS) and terrain analysis-based SCIMAP (Sensitive Catchment Integrated Modelling and Analysis Platform) approach; and the use of a high spatial resolution drone dataset as an improved input data for SCIMAP modelling. Each of these methods captures the locations of the CSAs, revealing similarities and differences in the prioritisation of CSA features. The differences are due to the temporal and spatial resolution of the three methods such as the use of static land cover information, the ability to capture small scale features, such as gateways and the incomplete catchment coverage of the walkover survey. The relative costs and output resolutions of the three methods indicate that they are suitable for application at different catchment scales in conjunction with other methods. Based on the results in this paper, it is recommended that a multi-evidence-based approach to diffuse pollution management is taken across catchment spatial scales, incorporating local knowledge from the walkover with the different data resolutions of the SCIMAP approach.

Energy policy as a social determinant of Australian health equity

Background

Intersectoral action on social determinants of health to reduce health inequities requires policy research beyond the usual social and human services. We ask how Australian energy policy affects health equity.

Methods

Document analysis and policy case studies on how goals, objectives and strategies of all Australian energy policies address equity.

Results

Energy policy affects health via risk from unreliable energy; difficult transitions to renewables; disproportionate effects on poorer people faced with high energy bills versus other basics; ecological degradation; cost pressures on businesses and governments; job losses and policy paralysis about renewable energy and climate change. Policy features subsidies for the disadvantaged; privatisation and artificial markets; differing geographical distribution of resources and high level political conflict about whether it can deliver on 3, or only 2, of the ’energy trilemma’ of reliability, affordability and ecological sustainability. Mining, industrial and political interests, powerful enough to orchestrate the downfall of Australian prime ministers, actively close policy links between health, climate change and energy. Bridging energy and health policy requires political support for market solutions involving renewables; community generation of renewable energy; solutions for rural and remote areas; and global treaties. Intergenerational equity is a strong policy lever.

Conclusions

Health in All Policies approaches can creatively engage with the language and concepts of energy policy via the daily conditions of living, inequity and climate change. When it is difficult to engage, researchers can connect with non-government organisations who bridge sectors through simultaneous advocacy for equitable health, climate and energy policies.

Key messages

Powerful interests burn bridges between health equity and energy policy. Local and global policy levers harmonising terminology differences build bridges between energy, climate change and health equity.

A multicentre, randomised, sham-controlled trial on REmote iSchemic conditioning In patients with acute STroke (RESIST) - Rationale and study design

Rationale

Remote ischaemic conditioning, applied in the prehospital setting and continued in-hospital, may improve functional outcome in patients with acute ischaemic stroke and intracerebral haemorrhage.

Aims

To evaluate whether combined remote ischaemic per- and postconditioning can improve long-term functional outcome in acute ischaemic stroke and intracerebral haemorrhage patients.

Methods and design

Danish multicentre, prospective, randomised, patient-assessor blinded, sham-controlled study. Adult patients with a putative stroke identified prehospital with symptom duration <4 h, who are independent in daily activities will be randomised 1:1 to remote ischaemic conditioning or Sham-remote ischaemic conditioning. The treatment protocol will be five cycles, each consisting of 5 min with a blood pressure cuff inflation and 5 min with a deflated cuff placed on the upper extremity. The cuff pressure for remote ischaemic conditioning will be 200 mmHg-285 mmHg according to the individual systolic blood pressure and 20 mmHg sham-remote ischaemic conditioning during inflation. The study is approved as an acute study and consent is waived in the acute phase.Sample size estimation: For a 7% increased odds for a beneficial shift on the modified Rankin Scale at a significance level of 5% and power of 90%, 1000 patients with a target diagnosis of acute ischaemic stroke and intracerebral haemorrhage and a total of 1500 patients with a prehospital presumed stroke will be included.Study outcomes: The primary outcome will be the modified Rankin Scale score measured at three-month follow-up (analysed using ordinal logistic regression). ClinicalTrials.gov Identifier: NCT03481777.

High-Resolution Magnetic Resonance Imaging of Cervicocranial Artery Dissection: Imaging Features Associated With Stroke

Background and Purpose- We aimed to systematically investigate the characteristics of cervicocranial artery dissection (CCAD) on high-resolution magnetic resonance imaging that are associated with acute ischemic stroke. Methods- Patients with CCAD were recruited and divided into stroke and nonstroke groups. The lesion location, the presence of a double lumen, intimal flap, intramural hematoma, pseudoaneurysm, irregular surface, intraluminal thrombus, and other quantitative parameters of each dissected segment were reviewed. Multiple logistic regression was used to examine the association between imaging features of CCAD and ischemic stroke. Results- A total of 145 affected vessels from 118 patients with CCAD were analyzed. Anterior circulation, intramural hematoma, irregular surface, intraluminal thrombus, and severe stenosis (>70%) on high-resolution magnetic resonance imaging were more prevalent in CCAD patient with stroke (54.4% versus 36.4%; P=0.030, 96.2% versus 84.8%; P=0.017, 74.7% versus 37.9%; P<0.001, 44.3% versus 4.5%; P<0.001, and 54.4% versus 31.8%; P=0.008, respectively). In multivariable logistic regression analysis, the presence of irregular surface and intraluminal thrombus on imaging were independently associated with acute ischemic stroke in CCAD with odds ratios of 4.29 (95% CI, 1.61-11.46, P=0.004) and 7.48 (95% CI, 1.64-34.07, P=0.009). Conclusions- The current findings supported that the presence of irregular surface and intraluminal thrombus were related to stroke occurrence in patients with CCAD. High-resolution magnetic resonance imaging might give insights into pathogenesis of ischemic stroke in CCAD. It may be useful for individual prediction of ischemic stroke early in CCAD.

Inhibition of PTP1B Promotes M2 Polarization via MicroRNA-26a/MKP1 Signaling Pathway in Murine Macrophages

Sepsis is a life-threatening condition that often occurs in the intensive care unit. The excessive activation of the host's immune system at early stages contributes to multiple organ damage. Mitogen-activated protein kinase phosphatase-1 (MKP1) exerts an important effect on the inflammatory process. In our recent bioinformatic analysis, we confirmed that the inhibition of protein tyrosine phosphatase-1B (PTP1B) significantly promoted the expression of MKP1 in murine macrophages. However, the underlying mechanism and its effect on macrophage polarization remain unclear. In this study, we show that the suppression of PTP1B induced upregulation of MKP1 in M1 macrophages. A RayBiotech mouse inflammation antibody assay further revealed that MKP1-knockdown promoted pro-inflammatory cytokine (IL-1β, IL12p70, IL-17, IL-21, IL-23, and TNF-α) secretion but suppressed anti-proinflammatory cytokine (IL-10) production in M2 macrophages. Phospho-proteomics analysis further identified ERK1/2 and p38 as downstream molecules of MKP1. Moreover, we found that the inhibition of PTP1B lowered the expression of miR-26a, showing a negative correlation with MKP1 protein expression. Thus, we concluded that the inhibition of PTP1B contributes to M2 macrophage polarization via reducing mir-26a and afterwards enhancing MKP1 expression in murine macrophages.

Transfemoral Approach to Induce Transient Middle Cerebral Artery Occlusion in Rats: The Use of Commercially Available Endovascular Wires

BACKGROUND

Animal models of stroke play a crucial role in determining the pathophysiology of stroke progression and assessment of any new therapeutic approaches. Transient middle cerebral artery occlusion (tMCAo) in rodent models are the most common site-specific type of ischemia because of their relevance to the clinical setting. Compared with the intraluminal filament technique for inducing tMCAo, the transfemoral approach using endovascular wires is relatively a new technique METHODS: Here we present the use of commercially available wires used for neuro-endovascular surgical procedures to induce tMCAo in rats via a transfemoral approach. We used male Wistar rats in four groups to assess the effect of occlusion time (1 vs. 2 hours) and the wire type (PT2 TM 0.014″ vs. TransendTM EX, 0.014″, Boston Scientific, MA, USA). Infarct volume, edema, neurological deficits, and pro-inflammatory/anti-inflammatory blood biomarkers were used as outcome measures.

RESULTS

We observed a significant effect of the wire type on the infarct volume (p value = 0.0096) where infarcts were slightly larger in the PT2 wiregroups. However, the occlusion time had no significant effect on infarct volume, even though the interaction between wire-type * occlusion-time was significant (p value = 0.024). Also, the amount of edema and blood pro-inflammatory/anti-inflammatory biomarkers were not statistically different among the wire-type and occlusion-time groups.

CONCLUSIONS

The choice of appropriate endovascular wire should probably be the focus of the study design instead of the occlusion time when planning an experiment. The transfemoral approach using endovascular wires for inducing tMCAo in rats provides a more consistent outcome with fewer complications compared with suture filament models.

A Brief Review of Edema-Adjusted Infarct Volume Measurement Techniques for Rodent Focal Cerebral Ischemia Models with Practical Recommendations

BACKGROUND

Determining cerebral infarction volume is an important part of preclinical studies to determine the benefit of potential therapies on stroke outcome. A well-known problem in determining the actual infarction volume of rodent models is the presence of edema. Because of this, algorithms must be utilized to obtain the edema-adjusted (E _A)-infarct volume. Different methods based on 2,3,5-triphenyltetrazolium hydrochloride (TTC) staining have been published describing algorithms to determine the E _A-infarct volume.

MATERIALS AND METHODS

Simulated models of infarction and corresponding swelling were employed to determine which absolute method of calculation (Lin et al., Reglodi et al., or Belayev et al.) is the most accurate in calculating the absolute E _A-infarct volume.

RESULTS

The Reglodi and Belayev methods were statistically more accurate in measuring E _A-infarct volume than Lin's method, p = 0.0078. Though there was no significant difference between Reglodi's and Belayev's methods for the E _A-infarction volume calculation, Reglodi's approach was closer to the ground-truth infarct volume while also being simpler and more straightforward to use.

CONCLUSION

We recommend that Reglodi's method, that is E _A-infarct volume = infarct volume × (contralateral hemisphere/ipsilateral hemisphere), to be used in calculating E _A-infarct volume in TTC stained rodent brains. Further, factors such as inhomogeneous infarction distribution in a given brain slice can also contribute to the error in volume calculation. Therefore, the average of the infarct area obtained from anterior and posterior views of a given slice should be used to account for the variation. Considering different factors, we have provided a summary recommendation for calculating the infarction volume.

SAT-427 Low Chloride Transporter Expression in Vasopressin Neurons

Several membrane proteins function as ion pumps/transporters that work to maintain the relative ionic concentrations necessary for neuronal signaling. The potassium-chloride co-transporter two (KCC2) is a symporter that actively pumps K⁺ and Cl^- out of the cell in order to maintain a low intracellular [Cl^-], while the sodium-potassium-chloride cotransporters one and two (NKCC1/NKCC2) are symporters that actively pump Na⁺, K⁺, and Cl^- into the cell. KCC2 and NKCC1/2, therefore, have opposing actions on Cl^- transport. In the adult, high KCC2 expression leads to low intracellular [Cl^-], which causes GABA_A receptor Cl- channels to flux Cl^- into the neuron, causing a membrane hyperpolarization. Early in development however, low KCC2 expression reverses the Cl^- gradient and causes GABA_A receptors to flux Cl^- out of the neuron, leading to membrane depolarization and neuronal excitation. The change in the polarity of GABA signaling during development is, in part, due to a shift in KCC2 expression from low to high with the maturation of synaptic circuits. Our previous studies have demonstrated an excitatory GABA_A receptor-mediated response due to a GABA equilibrium potential (E_GABA) that is shifted positive, like that seen early in development, in adult vasopressin (VP)-secreting neurons of the rat hypothalamus. In the current study, we used immunohistochemistry to compare expression levels of the main C^l- transporters, KCC2, NKCC1, and NKCC2, between VP- and oxytocin (OT)-secreting neurons of the hypothalamic paraventricular and supraoptic nuclei. We found that, in adult male Wistar rats, expression of all three transporters is uniformly lower in VP neurons than in adjacent OT neurons in the hypothalamus. Because the phosphorylation state of KCC2 affects membrane trafficking and stabilization, we are also using Western blot to analyze phosphorylation of KCC2 under different osmotic conditions. Finally, we are using Cre-dependent viral transduction to express a light-activatable Cl^- channel conditionally in vasopressin-secreting neurons to test for the effect of Cl^- flux on vasopressin secretion.

Predictors of successful endovascular treatment in severe cerebral venous sinus thrombosis

Objective

The objective of this study was to evaluate the thrombus characteristics affecting the extent of recanalization to identify patients with severe cerebral venous sinus thrombus (CVT) more likely to benefit from endovascular therapy.

Methods

Severe CVT patients scheduled for endovascular treatment were prospectively recruited into the study. Each thrombosed venous segment was evaluated regarding complete or partial recanalization based on digital subtraction angiography (DSA) after treatment. Magnetic resonance black‐blood thrombus imaging (MRBTI) was performed 1 day before endovascular treatment. The signal‐to‐noise ratio (SNR) of the clot, age of the clot, and baseline volume of the clot were compared between the complete and partial recanalization groups. A logistic regression analysis was performed to identify the association between these clot characteristics and recanalization status.

Results

Twenty‐one CVT patients undergoing endovascular therapy were prospectively included. There were 110 thrombosed segments, 54 of these segments were completely recanalized after endovascular treatment. An acute clot sign (ACS) was found in 39 segments and a subacute clot sign (SCS) was found in 71 segments. There was no significant difference on baseline volume of the clot (1638.8 ± 1432.2 mm³ vs. 1957.5 ± 2056.1 mm³, P > 0.05) between the complete and partial recanalization groups. Logistic regression analysis showed that ACS on MRBTI was associated with complete recanalization (P < 0.001, odds ratio = 3.937, 95% confidence interval, 1.6–9.5).

Interpretation

ACS can be used to predict complete recanalization in patients undergoing endovascular treatment. MRBTI provides a robust method to define clot composition and is potentially useful in selecting the most appropriate CVT patients for endovascular treatment.

Management of Acute Ischemic Stroke

The treatment of acute ischemic stroke includes both intravenous (IV) thrombolysis and mechanical thrombectomy. Important advances regarding both treatment modalities have occurred recently that all physicians who see patients at risk for or who have had a stroke should be aware of. This review will focus on recent clinical trials of IV thrombolysis both positive and negative. Additionally, the results of a large number of early and late time window thrombectomy trials will be presented that demonstrate the remarkable efficacy of this treatment for appropriately selected patients.

Effectiveness of acupuncture for vascular cognitive impairment no dementia: a randomized controlled trial

OBJECTIVE:

To evaluate the effectiveness of acupuncture in patients with vascular cognitive impairment no dementia (VCIND) in comparison with citicoline, an agent for cognitive disturbances associated with chronic cerebral disorders.

DESIGN:

A randomized controlled multicenter trial.

SETTING:

In three hospitals in Beijing, China.

SUBJECTS:

A total of 216 patients with VCIND were recruited.

INTERVENTIONS:

Patients with VCIND (mean age of 65.4 years) were randomized to receive acupuncture (two sessions per week) or oral citicoline (100 mg three times daily) over three months.

MAIN MEASURES:

The primary outcome was the change from baseline to three months in cognitive symptom, measured by Alzheimer's disease Assessment Scale, cognitive subscale (ADAS-cog). Secondary outcomes included changes from baseline to six months in ADAS-cog, executive function measured by the Clock Drawing Test (CDT), and functional disability measured by the Ability of Daily Living (ADL) scale at three and six months.

RESULTS:

At three months, the acupuncture group had a greater decrease in mean ADAS-cog score (-2.33 ± 0.31) than the citicoline group (-1.38 ± 0.34) with a mean difference of -0.95 (95% CI, -1.84 to -0.07, P = 0.035). The mean change from baseline to six months in ADAS-cog also significantly favored acupuncture treatments (acupuncture change -2.61 vs citicoline -1.25, difference: -1.36 points; 95% CI, -2.20 to -0.51; P = 0.002). There was no difference between the two groups on CDT and ADL scores at either time point.

CONCLUSION:

Compared with citicoline, acupuncture has comparable and even superior efficacy with improved cognitive and daily living performance as a complementary and alternative medicine treatment for VCIND.

Reducing peak pressures under the saddle at thoracic vertebrae 10-13 is associated with alteration in jump kinematics

There is little information about horse-saddle interaction at take-off for a fence, although there is potential that this could have an influence on performance. It was hypothesised that (1) maximum peak pressure under the saddle would occur in the phase of maximum thoracolumbar flexion prior to hindlimb take-off; and (2) limb and trunk kinematics at take-off over the fence would be affected by reducing peak pressure at Thoracic vertebrae (T)10-13 at the point in the stride where peak pressures occur. The peak pressures under the usual saddle (Saddle S) and a saddle modified to reduce peak pressures at T10-13 (Saddle F) were measured during approach and take-off over a 1.30 m upright fence in 12 elite jumping horses. The timing of peak pressures was determined by comparison with simultaneous video data. Shoulder, carpal flexion angle and trunk angle to the horizontal at hindlimb take-off, take-off distance from the fence and fetlock height above the fence were determined using high speed motion analysis. Peak pressures under the saddle at T10-13 and kinematic data were compared between Saddles S and F. Maximum peak pressures occurred at forelimb vertical, during hindlimb protraction, consistent with thoracolumbar ventroflexion. Saddle F was associated with significantly lower peak pressures at T10-13, greater shoulder and carpal flexion, a steeper trunk angle, and higher fetlock height above the fence than Saddle S. Forelimb take-off distance from the fence was not different between saddles, but hindlimbs were significantly closer to the fence with Saddle F, indicating potential increase in ventroflexion through the thoracolumbosacral region. These findings suggest that reducing peak pressures under the saddle at T10-13 are associated with altered kinematics during the approach and take-off over a fence, which may have a positive effect on jumping performance.