105 EVALUATION OF A NEW PHYSIOTHERAPY-LED VESTIBULAR SERVICE EMBEDDED IN THE FALLS AND SYNCOPE UNIT

Background

Clinical presentations in the falls and syncope unit (FASU) are diverse and require a range of skillsets. Vestibular disorders amount to a significant proportion of presentations. In our FASU, we embedded a 0.5 FTE specialist physiotherapist with expertise in vestibular disorders to work alongside medical and nursing staff. We conducted a service evaluation of the activity of this new service.

Methods

Retrospective Service Evaluation Approval was granted by our Research & Innovation Office. Pseudonymised data was collected corresponding to all new FASU physiotherapy service attendances between August 2021 and May 2022. Descriptive statistics were complemented by a binary logistic regression model to establish independent predictors of more than one physiotherapy session being required over the period.

Results

There were 104 episodes recorded by the new service, corresponding to 101 unique patients. Mean age was 67.7 (SD 19.0, range 17-93), and 73.1% were women. 67% were treated and discharged in 1 session. On average, patients had had a mean of 2 falls prior to the consultation (range 0-25). 28.8% were using a walking aid, and 54.8% self-reported fear of falling. 25% of the referrals to the service were due to suspected vestibular disorders, 62% of which were directly treated by the physiotherapy service. The logistic regression model adjusting by age, sex, use of walking aid, number of falls, and fear of falling showed that only referral for vestibular disorder was an independent predictor of patients needing more than 1 physiotherapy treatment (OR 3.91, 95% CI 1.32-11.58, P=0.014).

Conclusion

Vestibular disorders are common in FASU, and a majority can be treated by a specialist physiotherapy service. Repeated vestibular maneuvers are often needed in such patients. A responsive, embedded physiotherapy service in FASU can directly address this need and further evaluation will focus on the impact of this service on avoidance of ED attendances.

110 DEVELOPMENT AND DELIVERY OF A MULTI-DISCIPLINARY HYBRID EDUCATION PROGRAM IN SYNCOPE AND RELATED DISORDERS DURING THE COVID-19 PANDEMIC

Background

Syncope and related disorders is an important area for training of all health professionals. During the COVID-19 pandemic, we adapted the delivery of our annual face-to-face certified program to a 9-month hybrid program. Here, we describe the development, delivery, and evaluation of such new program.

Methods

A pre-existing curriculum was modified to incorporate online content, online lecture delivery and interactive group learning, in addition to individual practical placements in a syncope management unit, in line with government and hospital infection control guidance at the time. Monthly content included video consultant case presentations, ECG analysis and interpretation, and instructional videos of diagnostic testing and relevant technologies. A comprehensive online week-long lecture program was developed.

Results

The lecture week included 30 clinical lectures, 10 clinical case presentations and 10 ‘how to’ practical videos for testing/monitoring procedures. Further learning over zoom incorporated learner case presentations in a small group format. At the completion of the course the leaners attended a final online half day of lectures and completed the multi choice question examination.

Conclusion

“Thank you so much for putting together such a fantastic week of training.” “The quality and expertise of the speakers was outstanding.” “I have taken a huge amount away to incorporate into my practice and local unit.”

The above learner feedback is consistent with our aim to deliver a high-quality specialist program for those interested in advancing the management of syncope and related disorders. Over time, this specialist training will aid the development of regional syncope management units across Ireland. The benefits of a hybrid learning model include multiple options to cater for all categories of learners, thus suggesting it is the cornerstone of future learning modalities.

281 PREVALENCE OF STOPPFALL FALLS-RISK-INCREASING DRUGS (FRIDS) IN PATIENTS PRESENTING TO HOSPITAL WITH A FALL

Background

Falls cause presentation and admission to hospital. Falls-Risk-Increasing-Drugs (FRIDs) are a modifiable risk factor. STOPPFalls criteria was developed, using an expert Delphi panel, to achieve consensus on a comprehensive list of FRIDs. The aim of this study was to identify the prevalence of STOPPFall PRIDs in patients presenting to hospital with falls and identify whether review by a specialist Falls and Syncope Service (FASS) reduces FRIDs.

Methods

This was a retrospective observational study. Patients ≥65 years reviewed by the hospital FASS in the emergency department (over 6-months) and in house (over 2-months), were included. Medication appropriateness at admission and discharge were assessed using STOPPFall criteria. Ethical approval was received from the local research and innovation office (ref7013).

Results

Of 156 patients, 87(55.8%) were ≥65 years; 46% female, mean age 78.1(SD7.5) years. The mean number of conditions was 4(SD4.4); the mean number of regular medications was 6.9(SD4.5). Reasons for referral to FASS included falls (34.5%), dizziness/near fall (35.6%), and transient loss of consciousness (29.9%). For 21.8% there was an associated injury; 11.5% a fracture. Thirty-seven (42.5%) had experienced at least one fall in the previous 12-months.

Sixty-four (73.6%) were on ≥1 STOPPFall FRID. The most common STOPPFall FRID prescribed to older adults were diuretics (24.1%), anti-depressants (20.7%) and benzodiazepines/benzodiazepine-related drugs (13.8%). At least 1 STOPPFall FRID was stopped in 31.3%. The most commonly deprescribed STOPPFall FRIDs were diuretics (20%), alpha blockers (6%) and benzodiazepines/benzodiazepine-related drugs (4.7%). Adults <65years (n=69) were more likely to be prescribed a STOPPFall FRID at admission than older adults (≥65years); 88.4% vs 73.6%, p=0.021.

Conclusion

STOPPFall FRIDs are prevalent in fallers of all ages. Even one review by a specialist FASS leads to medication optimization. The effectiveness of STOPPFalls criteria in the prevention of falls should be evaluated further in intervention studies.

204 FRAILTY BUT NOT AGE IS ASSOCIATED WITH IMPAIRED ORTHOSTATIC CEREBRAL OXYGENATION

Background

The effects of age and frailty on cerebrovascular function are poorly understood. Here we investigate the hypotheses that aging, and frailty are accompanied by impaired regulation of cerebral oxygenation during standing in a patient population of older adults.

Methods

We recruited patients from a national Falls and Syncope service. All patients underwent an active stand test (5–10 min lying, 3 min standing) with continuous monitoring of blood pressure (BP) and heart rate. Tissue saturation index (TSI) was concurrently measured using near-infrared spectroscopy and its recovery measured at 30s after standing. Frailty was assessed as a comorbidity count using a 27-item questionnaire. Robust linear regression was used to investigate the association between TSI, age and frailty in a multivariate model with covariate adjustment, including the concurrent BP values. A p-value <0.05 was considered significant.

Results

304 patients (median(IQR): 71(14) years, 57% females) were recruited. Age was not associated with cerebral oxygenation after standing (β: −0.001 (−0.017 0.015), p = 0.899), even after stratification by sex (males: β: −0.010 (−0.045 0.024), p = 0.558, females: β: 0.000 (−0.017 0.018), p = 0.967). Frailty, was associated with a lower TSI at 30s after standing (β: −0.153 (−0.248–0.058), p = 0.002). After sex stratification, no associations with frailty were observed in males (β: −0.052 (−0.226 0.123), p = 0.557), while frailer females demonstrated a lower TSI at 30 seconds after standing (β: −0.179 (−0.294–0.063), p = 0.003) despite BP correction.

Conclusion

Our results suggest alternative mechanisms of cerebral oxygenation regulation independent of blood pressure (and presumably cerebral autoregulation) are involved in frailty related impairments of brain haemodynamics which are also independent of ageing. Such impairments represent novel biomarkers of frailty and represent potentially novel modifiable risk factors (independent of BP management) of hypoperfusion related disorders in clinical ageing.

Recent CO2 levels promote increased production of the toxin parthenin in an invasive Parthenium hysterophorus biotype

Recent carbon dioxide (CO₂) concentrations promoted higher parthenin concentrations in an invasive Parthenium hysterophorus biotype. Mean concentrations of parthenin, an allelopathic and defensive sesquiterpene lactone, were 49% higher at recent (~400 ppm) than at mid-twentieth-century (~300 ppm) CO₂ concentrations, but did not vary in a non-invasive biotype, suggesting that recent increases in atmospheric CO₂ may have already altered the chemistry of this destructive weed, potentially contributing to its invasive success.

Brain Injury Is More Common in Venoarterial Extracorporeal Membrane Oxygenation Than Venovenous Extracorporeal Membrane Oxygenation: A Systematic Review and Meta-Analysis

OBJECTIVES

Despite the common occurrence of brain injury in patients undergoing extracorporeal membrane oxygenation, it is unclear which cannulation method carries a higher risk of brain injury. We compared the prevalence of brain injury between patients undergoing venoarterial and venovenous extracorporeal membrane oxygenation.

DATA SOURCES

PubMed and six other databases from inception to April 2020.

STUDY SELECTION

Observational studies and randomized clinical trials in adult patients undergoing venoarterial extracorporeal membrane oxygenation or venovenous extracorporeal membrane oxygenation reporting brain injury.

DATA EXTRACTION

Two independent reviewers extracted the data from the studies. Random-effects meta-analyses were used to pool data.

DATA SYNTHESIS

Seventy-three studies (n = 16,063) met inclusion criteria encompassing 8,211 patients (51.2%) undergoing venoarterial extracorporeal membrane oxygenation and 7,842 (48.8%) undergoing venovenous extracorporeal membrane oxygenation. Venoarterial extracorporeal membrane oxygenation patients had more overall brain injury compared with venovenous extracorporeal membrane oxygenation (19% vs 10%; p = 0.002). Venoarterial extracorporeal membrane oxygenation patients had more ischemic stroke (10% vs 1%; p < 0.001), hypoxic-ischemic brain injury (13% vs 1%; p < 0.001), and brain death (11% vs 1%; p = 0.001). In contrast, rates of intracerebral hemorrhage (6% vs 8%; p = 0.35) did not differ. Survival was lower in venoarterial extracorporeal membrane oxygenation (48%) than venovenous extracorporeal membrane oxygenation (64%) (p < 0.001). After excluding studies that included extracorporeal cardiopulmonary resuscitation, no significant difference was seen in the rate of overall acute brain injury between venoarterial extracorporeal membrane oxygenation and venovenous extracorporeal membrane oxygenation (13% vs 10%; p = 0.4). However, ischemic stroke (10% vs 1%; p < 0.001), hypoxic-ischemic brain injury (7% vs 1%; p = 0.02), and brain death (9% vs 1%; p = 0.005) remained more frequent in nonextracorporeal cardiopulmonary resuscitation venoarterial extracorporeal membrane oxygenation compared with venovenous extracorporeal membrane oxygenation.

CONCLUSIONS

Brain injury was more common in venoarterial extracorporeal membrane oxygenation compared with venovenous extracorporeal membrane oxygenation. While ischemic brain injury was more common in venoarterial extracorporeal membrane oxygenation patients, the rates of intracranial hemorrhage were similar between venoarterial extracorporeal membrane oxygenation and venovenous extracorporeal membrane oxygenation. Further research on mechanism, timing, and effective monitoring of acute brain injury and its management is necessary.

Cerebral perfusion responses to active standing are attenuated in patients with vasovagal syncope

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Irish Research Council (IRC): Government of Ireland Postgraduate Scholarship Programme 2018, Dublin, Ireland Fundació Universitària Agustí Pedro i Pons, Universitat de Barcelona, Barcelona, Spain

Background

Syncope is a transient loss of consciousness due to cerebral hypoperfusion. While traditionally peripheral haemodynamics are monitored during clinical assessment of syncope, relatively little is known about cerebrovascular haemodynamics during orthostasis in patients with syncope.

Purpose

Here we investigated whether young patients with syncope present an altered cerebral perfusion when compared to healthy controls. Given potential hyper-reactivity of the autonomic nervous system previously reported in these patients, we hypothesise that an overly active cerebral autoregulation will be present in patients with syncope.

Methods

Consecutive patients were prospectively recruited from a National Falls and Syncope Unit, and a convenience sample of young healthy community dwelling adults was recruited from a local university (16-30 years). Participants performed a 3 minute active stand test with continuous measurement of beat-to-beat peripheral haemodynamics (blood pressure (BP), heart rate (HR)) and changes in concentration of oxygenated Δ[O2Hb] and deoxygenated Δ[HHb] haemoglobin were derived from a near-infrared spectroscopy (NIRS) monitor. Baseline, steady state and other time domain features were derived for Δ[O2Hb] (nadir, overshoot, overshoot-to-nadir, overshoot-to-nadir recovery rate) and Δ[HHb] (peak, trough, peak-to-trough, peak-to-trough recovery rate) and multiple linear regression was used to compare differences between the two groups correcting for covariates (p &lt; 0.05 significant).

Results

Patients (n = 40) were younger (20(5.5) vs 23(1) years, p = 0.003) than controls (n = 17) and were well matched in gender, weight, height, BMI and resting haemodynamics. Patients had a smaller Δ[O2Hb] overshoot-to-nadir difference (β: -0.749, CI:(-1.593 0.094), p = 0.08), a slower Δ[O2Hb] recovery rate (β: -0.186, CI:(-0.388 0.016), p = 0.071), and smaller Δ[HHb] peak-to-trough difference (β: -0.530, CI:( -0.921 0.138), p = 0.018) and slower Δ[HHb] recovery rate (β: -0.151, CI: (0.244 0.057), p = 0.008).

Conclusion

Patients with syncope had signs of an attenuated cerebral oxygenation response to an AS when compared to controls. We hypothesise that this is due to hyper-reactive cerebral autoregulation mechanism, which might be related to a hyper-sensitive autonomic system. Furthering our understanding of vasovagal syncope physiology can help inform future interventions and treatments. This study shows the clinical value of measuring cerebral perfusion using NIRS, an easy to use and readily applicable tool, in the assessment of syncope. Abstract Figure. Cerebral oxygenation upon standing

Do patients with syncope have a hyper-reactive autonomic nervous system?

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Irish Research Council (IRC): Government of Ireland Postgraduate Scholarship Programme 2018, Dublin, Ireland Fundació Universitària Agustí Pedro i Pons, Universitat de Barcelona, Barcelona, Spain.

Background

The origin of syncope, a transient loss of consciousness due to cerebral hypoperfusion, remains unclear. Recent studies suggest that a hypersensitive autonomic nervous system might be involved in the pathophysiology of vasovagal syncope (VVS).

Purpose

Here we test the hypothesis that patients with VVS have a hyper-reactive autonomic nervous system by investigating the peripheral haemodynamic responses during a standing (AS) test in a group of young VVS patients vs a control group.

Methods

A prospective sample of consecutive patients from a National Falls and Syncope Unit was recruited, and a convenience sample of young healthy community dwelling adults was recruited from a local university (16-30 years). Participants performed a 3 minute AS with continuous measurement of beat-to-beat blood pressure (BP), heart rate (HR), and cerebral oxygenation measured with near infrared spectroscopy. Baseline, steady-state and other time domain features were obtained for systolic BP (SBP) (i.e. nadir, overshoot, overshoot-to-nadir, overshoot-to-nadir recovery rate) and for HR (i.e. peak, trough, peak-to-trough, peak-to-trough recovery rate). Multiple linear regression was used to compare these features between patients and controls while correcting for covariates (p &lt; 0.05 significant).

Results

Forty patients and 17 controls were included, the former group being younger ((20(5.5) vs 23(1) years, p = 0.003). During steady-state standing SBP was higher as compared to controls (β: 6.853, CI: (0.713 12.993), p = 0.029). Patient data trended toward lower steady-state HR (β: -5.262, CI:(-11.201 0.677), p = 0.081), together with a larger peak-to-trough difference (β: 7.212, CI:(1.329 -15.754), p = 0.096).

Conclusion

These results tend to support the hypothesis and previous literature suggesting the presence of autonomic hyper-reactivity in patients with syncope, presenting as an exaggerated peripheral circulatory response to standing. Understanding the pathophysiology of VVS can help us improve its assessment and develop better treatment pathways for these patients. Abstract Figure.

Impact of a specialist service in the Emergency Department on admission, length of stay and readmission of patients presenting with falls, syncope and dizziness

BACKGROUND

Up to half of patients presenting with falls, syncope or dizziness are admitted to hospital. Many are discharged without a clear diagnosis for their index episode, however, and therefore a relatively high risk of readmission.

AIM

To examine the impact of ED-FASS (Emergency Department Falls and Syncope Service) a dedicated specialist service embedded within an ED, seeing patients of all ages with falls, syncope and dizziness.

DESIGN

Pre- and post-cohort study.

METHODS

Admission rates, length of stay (LOS) and readmission at 3 months were examined for all patients presenting with a fall, syncope or dizziness from April to July 2018 (pre-ED-FASS) inclusive and compared to April to July 2019 inclusive (post-ED-FASS).

RESULTS

There was a significantly lower admission rate for patients presenting in 2019 compared to 2018 [27% (453/1676) vs. 34% (548/1620); X2 = 18.0; P < 0.001], with a 20% reduction in admissions. The mean LOS for patients admitted in 2018 was 20.7 [95% confidence interval (CI) 17.4-24.0] days compared to 18.2 (95% CI 14.6-21.9) days in 2019 (t = 0.98; P = 0.3294). This accounts for 11 344 bed days in the 2018 study period, and 8299 bed days used after ED-FASS. There was also a significant reduction in readmission rates within 3 months of index presentation, from 21% (109/1620) to 16% (68/1676) (X2 = 4.68; P = 0.030).

CONCLUSION

This study highlights the significant potential benefits of embedding dedicated multidisciplinary services at the hospital front door in terms of early specialist assessment and directing appropriate patients to effective ambulatory care pathways.

1064 Sleep Patterns Among Urban Haitian Earthquake Survivors Who Experienced the Trauma of Nonpartner Sexual Violence: A Latent Class Analysis Approach

Introduction

Sleep health is crucial to recovery from trauma. Haiti’s Cité Soleil residents (approximately 350,000) live in extreme poverty and regularly experience or witness life-threatening events, including gang and non-partner sexual violence (NPSV). Differences in levels of sleep disturbance among men and women in resource-limited settings who survive disasters as well as NPSV are understudied. In a larger study in which we investigated trauma symptoms among 2010 Haiti earthquake survivors via the Trauma-symptom checklist -40 (N=526; 290 males, 236 females), we also assessed self-reported frequency of sleep disturbance symptoms using the measure’s sleep disturbance subscale, comparing the latter by NPSV victim status and by gender.

Methods

SAS enabled 3-Class Latent Class Analysis (LCA): Class 1 (“No symptoms”), Class 2 (“Some symptoms”), Class 3 (“All Symptoms)”.

Results

Distribution of class membership differed by gender (χ2 = 23.9, df = 2, p &lt; .0001). Proportions of respondents assigned to the three classes differed between genders (Females: Class 1, 29.2%; Class 2, 35.5%; Class 3, 35.3%); Males: Class 1, 25.7%; Class 2, 54.4%; Class 3, 19.9%). NPSV status influenced levels of sleep disturbance symptoms, and membership distribution differed across classes by gender (χ2 = 23.9, df = 2, p &lt; .0001). Class 2 membership was greater for men (65.9%), but class 3 membership was greater for women (59.3%). Women who experienced NPSV were statistically more likely members of sleep disturbance symptom classes (Class 2 or Class 3) than Class 1 (χ2= 14.9, df = 2, p = 0.0006). No difference was found in Class membership for men reporting NPSV (χ2= 1.6, df = 2, p = 0.45).

Conclusion

Investigating the sleep health of Cité Soleil residents adds to the body of literature on sleep health, sleep equity and gendered vulnerability. Findings suggest women in post-disaster settings, especially in LMICs, are at even greater risk for a variety of adverse health outcomes and for suboptimal sleep, even when local men have similar traumatogenic experiences, such as NPSV. Girls and women in post-disaster LMIC settings need trauma-informed sleep health promotion and NPSV-prevention.

Support

N/A

Abstract WP325: Peri-operative Neurological Complications of Valve Surgery for Infective Endocarditis Patients With Stroke

Introduction: Surgical valve repair is often delayed for infective endocarditis (IE) patients with stroke. We compared neurological outcome of early and delayed valve surgery and identified pre-surgical imaging characteristics that were associated with perioperative neurological complications.

Methods: We reviewed 228 patients with acute IE diagnosed by modified Duke’s Criteria who underwent cerebral angiogram (CA) between January 2010 - December 2016 at a single center. Patients without pre-surgical CT and MRI were excluded. Date of IE diagnosis was defined as date of antibiotic initiation. Early surgery was defined as valve replacement ≤14 days from date of IE diagnosis, delayed as >14 days. Peri-operative neurological complication is any new clinical or radiologic diagnosis of ischemic or hemorrhagic stroke, and seizure.

Results: 148 of 228 patients underwent valve surgery. 69 patients (46.6%) had early surgery at median 9 days after IE diagnosis, and 79 patients (53.4%) had delayed surgery at median 28 days. On pre-surgical imaging, acute to subacute ischemic stroke was seen in 81% of the early group (n=56) and 78% of the delayed group (n=62, p=0.69). However, 22.8% of patients (n=18) in the delayed group had evidence of subarachnoid hemorrhage (SAH) compared to 10.1 % of patients in the early group (n=7, p=0.04). Despite this finding, delayed group did not have higher rate of perioperative neurological complication than that of the early group (24.1% vs 13%, p=0.95). Overall, 15 surgical patients (10.1%) had perioperative neurological complications: 4 with acute ischemic stroke, 9 with ICH, 1 with both an infarct and ICH, and 3 with seizures. 33.3% of patients who had a perioperative neurological complication had evidence of SAH on pre-surgical imaging (n=6) compared to 14.6% of patients who did not have any neurological complications (n=19, p=0.012). In the group of patients with complications, SAH found prior to surgery were all cortical in the sulci, and 3 cases of SAH were associated with presence of infectious intracranial aneurysm found on pre-surgical CA.

Conclusion: In IE patients with stroke, presence of sulcal SAH on pre-surgical imaging is associated with developing perioperative neurological complications irrespective of surgical timing.

Abstract 162: Microhemorrhages in MRI Predict Infectious Intracranial Aneurysm in Infective Endocarditis

Background: MRI features such as cerebral microbleeds and sulcal susceptibility weighted imaging (SWI) or gradient-echo T2* (GRE-T2*) lesions have been reported to be associated with the presence of infectious intracranial aneurysm (IIA) in infective endocarditis (IE). We aimed to describe the MRI imaging features that predict the presence of IIA.

Methods: The derivation cohort comprised 116 IE patients with neurological evaluation at a single tertiary referral center from January 2015 to July 2016. The MRI predictors associated with IIA was evaluated, and we developed the MRI imaging predictors and assessed sensitivity and specificity. External validation was performed in a cohort of 129 IE patients who underwent digital subtraction angiogram (DSA) at the same center from 2010-2014. We assessed the validity using a receiver operating characteristic curve (ROC).

Results: Of 116 IE patients in the derivation cohort, 10 (9%) had IIAs. Of 129 in the validation cohort, 19 (15%) IIAs were identified. The MRI imaging predictors for IIA consist of 1) contrast enhancement with SWI lesions, 2) cerebral microbleeds > 5mm plus sulcal SWI lesions, and 3) any MRI hemorrhages. The sensitivity for the presence of IIA in each group of the derivation cohort was: 90%, 80%, and 100%, respectively. The sensitivity in the validation cohort was: 47%, 68%, and 94% respectively. The specificity in the derivation cohort was: 87%, 85%, and 18%. In the validation cohort, the specificity was similar (87%, 75%, and 27%).

Conclusions: The suggested MRI imaging predictors can be used as a sensitive and specific tool to support clinical decision-making, especially when invasive DSA is considered for assessment for presence of IIA. The absence of MRI hemorrhages may not necessitate the need for DSA.

Abstract TMP58: Is Lactate Dehydrogenase Level a Biomarker of Ischemic Stroke in Ventricular Assist Device?

Introduction: Lactate dehydrogenase (LDH) is used as a biomarker of pump thrombosis in patients with left ventricular assist device (LVAD). The relationship of LDH level to ischemic stroke remains unclear. We aimed to explore the relationship of LDH as a marker for LVAD-associated ischemic stroke.

Methods: We reviewed consecutive patients with ischemic stroke in a prospectively collected data of LVAD patients in a single, tertiary center from October 2004 to December 2016. LDH values from various time points were collected: at the time of stroke, and 1, 3, and 6-month (± 2 weeks) prior as controls. The clinical reference used for LDH’s normal range was 110 - 200 U/L. Pump thrombosis was diagnosed by isolated power elevations, LDH rise, evidence of hemolysis, and new heart failure symptoms as defined by the International Society for Heart and Lung Transplantation. The LDH levels were compared using Rank Sum test.

Results: Of 477 persons with LVAD, 61 (12.7%) developed ischemic stroke within a median of 143.5 days (Interquartile range [IQR] 10.5 - 410.2) from implantation to stroke event. Nineteen of 61 patients were diagnosed with pump thrombosis at the time of ischemic stroke. The LDH was significantly higher at the time of ischemic stroke with a median level of 500 [IQR 279 - 958] than at 6 months prior to stroke (median 294 [IQR 247 - 380], p= 0.001) or at 3 months prior to stroke (median 316 [IQR 270 - 420], p = 0.01), but not compared to those at 1 month prior to stroke (406 [IQR 228 -749], p= 0.28) (Figure).

Conclusion: Elevated LDH may not only be indicative of pump thrombosis but may start to rise before stroke occurrence and might serve as a risk marker for ischemic stroke.

Abstract WP331: Intracranial Hemorrhage in Infective Endocarditis: Underlying Arterial and Parenchymal Disease

Introduction: Intracranial hemorrhage (ICH) is a known complication of infective endocarditis (IE). We aimed to explore radiologic findings that may explain the cause of ICH and the prognosis of these patients.

Methods: We reviewed records of infective endocarditis cases with intraparenchymal hemorrhage (IPH) and subarachnoid hemorrhage (SAH) who underwent magnetic resonance imaging (MRI) and cerebral angiography at a single tertiary center from 2010 to 2014. All patients fulfilled modified Duke’s criteria for infective endocarditis.

Results: We identified 36 patients our inclusion criteria. Eleven (30%) had IPH only, 10 (28%) had SAH, and 15 (42%) had both. The most common presenting symptoms were focal neurological deficit (39%, n=14), encephalopathy (25%, n=9), followed by headache (19%, n=7). The hemorrhage was silent in (19%, n=7) cases. Twelve patients (33%) had mycotic aneurysms but only 4 had evidence of rupture (11%). Ten (28%) had distal arterial irregularities on angiography suggestive of vasculitis. Thirteen (36%) had evidence of microabscesses on MRI, and 22 (61%) had cerebral ischemia on MRI, of which 6 had a hemorrhagic transformation. In 24 out of 25 SAH cases cortical sulcal hemorrhage was seen and only one SAH was in the basal cistern. In 14 (56%) of these cortical SAHs had adjacent restricted diffusion lesion on the MRI. Among 21 patients undergoing valvular repair, only 2 (1%) were complicated with new intracranial hemorrhage that had no relation to the presence of microhemorrhages on MRI (p=0.42).

Conclusion: Intracranial hemorrhage in infective endocarditis is rarely related to mycotic aneurysms. Parenchymal involvement of infection or vascular inflammation may be the underlying causes for IPH and SAH in these patients.

Magnetic Resonance Imaging Susceptibility-Weighted Imaging Lesion and Contrast Enhancement May Represent Infectious Intracranial Aneurysm in Infective Endocarditis

Background: Infectious intracranial aneurysm (IIA) can complicate infective endocarditis (IE). We aimed to describe the magnetic resonance imaging (MRI) characteristics of IIA. Methods: We reviewed IIAs among 116 consecutive patients with active IE by conducting a neurological evaluation at a single tertiary referral center from January 2015 to July 2016. MRIs and digital cerebral angiograms (DSA) were reviewed to identify MRI characteristics of IIAs. MRI susceptibility weighted imaging (SWI) was performed to collect data on cerebral microbleeds (CMBs) and sulcal SWI lesions. Results: Out of 116 persons, 74 (63.8%) underwent DSA. IIAs were identified in 13 (17.6% of DSA, 11.2% of entire cohort) and 10 patients with aneurysms underwent MRI with SWI sequence. Nine (90%) out of 10 persons with IIAs had CMB >5 mm or sulcal lesions in SWI (9 in sulci, 6 in parenchyma, and 5 in both). Five out of 8 persons who underwent MRI brain with contrast had enhancement within the SWI lesions. In a multivariate logistic regression analysis, both sulcal SWI lesions (p < 0.001, OR 69, 95% CI 7.8-610) and contrast enhancement (p = 0.007, OR 16.5, 95% CI 2.3-121) were found to be significant predictors of the presence of IIAs. Conclusions: In the individuals with IE who underwent DSA and MRI, we found that neuroimaging characteristics, such as sulcal SWI lesion with or without contrast enhancement, are associated with the presence of IIA

Structural and functional analysis of the human POT1-TPP1 telomeric complex

POT1 and TPP1 are part of the shelterin complex and are essential for telomere length regulation and maintenance. Naturally occurring mutations of the telomeric POT1-TPP1 complex are implicated in familial glioma, melanoma and chronic lymphocytic leukaemia. Here we report the atomic structure of the interacting portion of the human telomeric POT1-TPP1 complex and suggest how several of these mutations contribute to malignant cancer. The POT1 C-terminus (POT1C) forms a bilobal structure consisting of an OB-fold and a holiday junction resolvase domain. TPP1 consists of several loops and helices involved in extensive interactions with POT1C. Biochemical data shows that several of the cancer-associated mutations, partially disrupt the POT1-TPP1 complex, which affects its ability to bind telomeric DNA efficiently. A defective POT1-TPP1 complex leads to longer and fragile telomeres, which in turn promotes genomic instability and cancer.

Structural Analysis Reveals the Deleterious Effects of Telomerase Mutations in Bone Marrow Failure Syndromes

Naturally occurring mutations in the ribonucleoprotein reverse transcriptase, telomerase, are associated with the bone marrow failure syndromes dyskeratosis congenita, aplastic anemia, and idiopathic pulmonary fibrosis. However, the mechanism by which these mutations impact telomerase function remains unknown. Here we present the structure of the human telomerase C-terminal extension (or thumb domain) determined by the method of single-wavelength anomalous diffraction to 2.31 Å resolution. We also used direct telomerase activity and nucleic acid binding assays to explain how naturally occurring mutations within this portion of telomerase contribute to human disease. The single mutations localize within three highly conserved regions of the telomerase thumb domain referred to as motifs E-I (thumb loop and helix), E-II, and E-III (the FVYL pocket, comprising the hydrophobic residues Phe-1012, Val-1025, Tyr-1089, and Leu-1092). Biochemical data show that the mutations associated with dyskeratosis congenita, aplastic anemia, and idiopathic pulmonary fibrosis disrupt the binding between the protein subunit reverse transcriptase of the telomerase and its nucleic acid substrates leading to loss of telomerase activity and processivity. Collectively our data show that although these mutations do not alter the overall stability or expression of telomerase reverse transcriptase, these rare genetic disorders are associated with an impaired telomerase holoenzyme that is unable to correctly assemble with its nucleic acid substrates, leading to incomplete telomere extension and telomere attrition, which are hallmarks of these diseases.

Abstract WP144: Ultrasound Criteria for Assessment of Vertebral Artery Origins

Introduction: We sought to validate ultrasound as a reliable means of assessing vessel stenosis of vertebral artery origins.

Methods: We reviewed 1135 patient charts with ultrasound of the posterior circulation performed 2008-2015 in our Neurovascular Laboratory Imaging Institute. Inclusion criteria consisted of ultrasound and digital subtraction angiography (DSA) performed within three months as well as absence of prior stent placement, resulting in 218 vessels in 133 patients. Using DSA as the gold standard, we determined sensitivity and specificity of ultrasound in detecting occlusion at vertebral artery origin. All patients with non-occluded vertebral artery origins without stent were evaluated for degree of stenosis on DSA, and compared to mean flow velocity (MFV) on ultrasound.

Results: Among 218 vertebral artery origins evaluated, ultrasound showed sensitivity of 85.7% (95% confidence interval (CI) 69.7-95.2%) for occlusion and specificity of 99. 5% (95%CI 96.9-99.9%). Among 126 arteries without occlusion, <50% stenosis had average MFV 39.5 cm/s (SD 19.9), 50-69% stenosis had average MFV 69.2 cm/s (SD 34.7), and severe 70-99% stenosis had average MFV 129 cm/s (SD 30.65), p<0.001 by Kruskal-Wallis test. For detecting ≥70% stenosis, c-statistic of ROC curve was 0.81, and MFV of 70 cm/s has 82% sensitivity and 88% specificity of ≥70% stenosis.

Conclusion: Ultrasound has good sensitivity and excellent specificity for detecting vertebral origin occlusion. Flow velocity can be used to screen for severe stenosis of vertebral artery at origin.

Structure and function of the telomeric CST complex

Telomeres comprise the ends of eukaryotic chromosomes and are essential for cell proliferation and genome maintenance. Telomeres are replicated by telomerase, a ribonucleoprotein (RNP) reverse transcriptase, and are maintained primarily by nucleoprotein complexes such as shelterin (TRF1, TRF2, TIN2, RAP1, POT1, TPP1) and CST (Cdc13/Ctc1, Stn1, Ten1). The focus of this review is on the CST complex and its role in telomere maintenance. Although initially thought to be unique to yeast, it is now evident that the CST complex is present in a diverse range of organisms where it contributes to genome maintenance. The CST accomplishes these tasks via telomere capping and by regulating telomerase and DNA polymerase alpha-primase (polα-primase) access to telomeres, a process closely coordinated with the shelterin complex in most organisms. The goal of this review is to provide a brief but comprehensive account of the diverse, and in some cases organism-dependent, functions of the CST complex and how it contributes to telomere maintenance and cell proliferation.

Structural Basis of Telomerase Inhibition by the Highly Specific BIBR1532

BIBR1532 is a highly specific telomerase inhibitor, although the molecular basis for inhibition is unknown. Here we present the crystal structure of BIBR1532 bound to Tribolium castaneum catalytic subunit of telomerase (tcTERT). BIBR1532 binds to a conserved hydrophobic pocket (FVYL motif) on the outer surface of the thumb domain. The FVYL motif is near TRBD residues that bind the activation domain (CR4/5) of hTER. RNA binding assays show that the human TERT (hTERT) thumb domain binds the P6.1 stem loop of CR4/5 in vitro. hTERT mutations of the FVYL pocket alter wild-type CR4/5 binding and cause telomere attrition in cells. Furthermore, the hTERT FVYL mutations V1025F, N1028H, and V1090M are implicated in dyskeratosis congenita and aplastic anemia, further supporting the biological and clinical relevance of this novel motif. We propose that CR4/5 contacts with the telomerase thumb domain contribute to telomerase ribonucleoprotein assembly and promote enzymatic activity.

Structure of the Human Telomeric Stn1-Ten1 Complex

The telomeric CST complex plays a central role in chromosome end capping and replication in budding yeast, and homologues of CST were identified recently in higher eukaryotes. The human CST (Ctc1, hStn1, hTen1) has been shown to play a role in telomere maintenance, but the extent of conservation across species has been in question because of low sequence identity (below 10% for Ctc1, the core subunit of the CST complex) and data suggesting subtle differences in function between complexes. We solved the high-resolution crystal structure of the human Stn1-Ten1 complex, which revealed striking structural similarity between the yeast and human CST complexes. We also showed using southern blots and fluorescence in situ hybridization experiments that disruption of the hStn1-Ten1 binding interface in vivo produces elongated telomeres and telomere defects in accordance with what has been previously observed for the yeast CST complex. Our results support structural and functional conservation of telomeric CST across species.

Reduced axonal motor protein expression in non-lesional grey matter in multiple sclerosis

Background:

Multiple sclerosis (MS) is a neurological disease characterised by central nervous system inflammation, demyelination, axonal degeneration and neuronal injury. Preventing neuronal and axon damage is of paramount importance in attempts to prevent disease progression. Intact axonal transport mechanisms are crucial to axonal integrity and evidence suggests these mechanisms are disrupted in MS. Anterograde axonal transport is mediated to a large extent through the kinesin superfamily proteins. Recently, certain kinesin superfamily proteins (KIF5A, KIF1B and KIF21B) were implicated in MS pathology.

Objectives:

To investigate the expression of KIF5A, KIF21B and KIF1B in MS and control post-mortem grey matter.

Methods:

Using both quantitative real-time polymerase chain reaction (PCR) and Immunodot-blots assays, we analysed the expression of kinesin superfamily proteins in 27 MS cases and 13 control cases not linked to neurological disease.

Results:

We have shown significant reductions in KIF5A, KIF21B and KIF1B messenger ribonucleic acid (mRNA) expression and also KIF5A protein expression in MS grey matter, as compared to control grey matter.

Conclusion:

We have shown significant reductions in mRNA and protein levels of axonal motor proteins in the grey matter of MS cases, which may have important implications for the pathogenesis of neuronal/axonal injury in the disease.

Structure of the human telomeric Stn1-Ten1 capping complex

The identification of the human homologue of the yeast CST in 2009 posed a new challenge in our understanding of the mechanism of telomere capping in higher eukaryotes. The high-resolution structure of the human Stn1-Ten1 (hStn1-Ten1) complex presented here reveals that hStn1 consists of an OB domain and tandem C-terminal wHTH motifs, while hTen1 consists of a single OB fold. Contacts between the OB domains facilitate formation of a complex that is strikingly similar to the replication protein A (RPA) and yeast Stn1-Ten1 (Ten1) complexes. The hStn1-Ten1 complex exhibits non-specific single-stranded DNA activity that is primarily dependent on hStn1. Cells expressing hStn1 mutants defective for dimerization with hTen1 display elongated telomeres and telomere defects associated with telomere uncapping, suggesting that the telomeric function of hCST is hTen1 dependent. Taken together the data presented here show that the structure of the hStn1-Ten1 subcomplex is conserved across species. Cell based assays indicate that hTen1 is critical for the telomeric function of hCST, both in telomere protection and downregulation of telomerase function.

Factors that influence awareness and treatment of atrial fibrillation in older adults

AIM

The aims of this study were to investigate the prevalence of atrial fibrillation (AF), treatment rates of AF and the factors underlying awareness and treatment, in a large nationally representative study.

METHODS

A population sample of people aged 50+, living in the Republic of Ireland, were recruited as part of The Irish longitudinal study on ageing. Ten-minute electrocardiogram recordings were obtained (n = 4890), and analysed to detect AF. Self-reported arrhythmias, subjective and objective health measures (cardiovascular diseases, CHA2DS2-VASc variables and blood pressure) and medications were also recorded. Logistic regressions were used to determine associations with outcomes of presence of AF, lack of awareness and untreated AF.

RESULTS

Overall prevalence of AF was 3% (95% CI: 2.4-3.7%), with a marked age gradient and sex difference [4.8% (men) vs. 1.4% (women); P < 0.0001]. In total, 67.8% were at high risk of stroke (CHA2DS2-VASc ≥ 2), of whom 59.3% were inadequately treated. A high proportion of 38.1% were unaware of having AF. CHA2DS2-VASc nor HAS-BLED score influenced awareness or treatment. Lack of awareness was associated with lower education (P = 0.01), lower cognition (P = 0.04), rural location (OR = 3.67; P = 0.02) and number of general practitioner visits (P = 0.01), whereas untreated AF was influenced by frailty status (P = 0.04).

CONCLUSION

With projected doubling of numbers of persons over 80 in the next 30 years in the British Isles, detection and management of AF is pressing. Two-thirds of adults at high risk of stroke were inadequately treated. More regular screening for AF, application of criteria for stroke and bleeding risk and awareness of factors influencing diagnosis and treatment is recommended.

Soil Nutrients, Bacteria Populations, and Veterinary Pharmaceuticals across a Backgrounding Beef Feedlot

Beef cattle backgrounding operations that grow out weaned calves for feedlot finishing contain several environmentally significant constituents. A better understanding of these constituents and their environmental distribution will aid in the development of effective management guidelines for sustainable beef production. This research investigated soil nutrients, bacterial, and veterinary pharmaceutical concentrations across a small backgrounding beef feedlot on a karst landscape. Results indicated that all contaminants were highly concentrated in the feeder area (FD) and were lower in the other feedlot areas. The FD soils had a pH of 8.2, 59 mg kg soil organic matter (SOM), 2002 mg kg soil test phosphorus (STP), 99.7 mg kg NH-N, and 18.3 mg kg NO-N. The other locations were acidic (5.9-6.9 pH) and contained 39 mg kg SOM, 273 mg kg STP, 21.5 mg kg NH-N, and 2.0 NO-N mg kg. Bacteria populations in the FD averaged 2.7 × 10 total cells, 3.9 × 10 spp., 2.9 × 10 spp, and 4.5 × 10 cells per gram of soil. spp. and spp. concentrations were 1 to 4 orders of magnitude lower at the other locations. showed lower dynamic range and was generally uniformly distributed across the landscape. Antibiotic and parasiticide concentrations in the FD were 86.9 ng g monensin, 25.0 ng g lasalocid, and 10.3 ng g doramectin. Their concentrations were 6- to 27-fold lower in the other feedlot locations. Contaminant management plans for this small feedlot will therefore focus on the feeder and nearby grazing areas where soil nutrients, bacteria populations, and veterinary pharmaceuticals were most concentrated.

Resource utilisation for syncope presenting to an acute hospital Emergency Department

BACKGROUND

Syncope is a common clinical problem accounting for up to 6% of hospital admissions. Little is known about resource utilisation for patients admitted for syncope management in Ireland.

AIM

To determine the utilisation of resources for patients admitted for syncope management.

METHODS

Single centre observational case series of consecutive adult patients presenting to an acute hospital Emergency Department with syncope over a 5-month period.

RESULTS

Two-hundred and fourteen of 18,898 patients (1.1%) had a syncopal episode, 110 (51.4%) of whom were admitted. Mean length of stay was 6.9 days. Sixty-four of these admissions were deemed unnecessary by retrospective review when compared to ESC guidelines. Eighty-five (77.3%) admitted patients had cardiac investigations and 56 (51%) had brain imaging performed.

CONCLUSIONS

Syncope places a large demand on overstretched hospital resources. Most cases can be managed safely as an outpatient and to facilitate this, hospitals should develop outpatient Syncope Management Units.