Molecular mechanism of complement inhibition by the trypanosome receptor ISG65

African trypanosomes replicate within infected mammals where they are exposed to the complement system. This system centres around complement C3, which is present in a soluble form in serum but becomes covalently deposited onto the surfaces of pathogens after proteolytic cleavage to C3b. Membrane-associated C3b triggers different complement-mediated effectors which promote pathogen clearance. To counter complement-mediated clearance, African trypanosomes have a cell surface receptor, ISG65, which binds to C3b and which decreases the rate of trypanosome clearance in an infection model. However, the mechanism by which ISG65 reduces C3b function has not been determined. We reveal through cryogenic electron microscopy that ISG65 has two distinct binding sites for C3b, only one of which is available in C3 and C3d. We show that ISG65 does not block the formation of C3b or the function of the C3 convertase which catalyses the surface deposition of C3b. However, we show that ISG65 forms a specific conjugate with C3b, perhaps acting as a decoy. ISG65 also occludes the binding sites for complement receptors 2 and 3, which may disrupt recruitment of immune cells, including B cells, phagocytes, and granulocytes. This suggests that ISG65 protects trypanosomes by combining multiple approaches to dampen the complement cascade.

Characterization of the major surface glycoconjugates of Trypanosoma theileri

Trypanosoma theileri maintains a long-term extracellular infection with a low parasitaemia in bovids. The surface of this parasite is predicted to be decorated with several surface molecules including membrane surface proteases (MSPs), trans-sialidases and T. theileri putative surface proteins (TTPSPs). However, there are no experimental data to verify this hypothesis. Here, we have purified and partially characterized the surface glycoconjugates of T. theileri using biochemical and mass spectrometry-based approaches. The glycoconjugates fall into two classes: glycoproteins and glycolipids. Proteomic analysis of the glycoprotein fraction demonstrated the presence of MSPs and abundant mucin-like TTPSPs, with most predicted to be GPI-anchored. Mass spectrometric characterization of the glycolipid fraction showed that these are mannose- and galactose-containing glycoinositolphospholipids (GIPLs) that are larger and more diverse than those of its phylogenetic relative T. cruzi, containing up to 10 hexose residues and carrying either alkylacyl-phosphatidylinositol or inositol-phospho-ceramide (IPC) lipid components.

Trypanosomes and complement: more than one way to die?

African trypanosomes show a remarkable ability to survive as extracellular parasites in the blood and tissue spaces of an infected mammal. Throughout the infection they are exposed to the molecules and cells of the immune system, including complement. In this opinion piece, we review decades-worth of evidence about how complement affects African trypanosomes. We highlight the discovery of a trypanosome receptor for complement C3 and we critically assess three recent studies which attempt to provide a structural and mechanistic view of how this receptor helps trypanosomes to survive in the presence of complement.

Shining the spotlight on the neglected: new high-quality genome assemblies as a gateway to understanding the evolution of Trypanosomatidae

BACKGROUND

Protists of the family Trypanosomatidae (phylum Euglenozoa) have gained notoriety as parasites affecting humans, domestic animals, and agricultural plants. However, the true extent of the group's diversity spreads far beyond the medically and veterinary relevant species. We address several knowledge gaps in trypanosomatid research by undertaking sequencing, assembly, and analysis of genomes from previously overlooked representatives of this protistan group.

RESULTS

We assembled genomes for twenty-one trypanosomatid species, with a primary focus on insect parasites and Trypanosoma spp. parasitizing non-human hosts. The assemblies exhibit sizes consistent with previously sequenced trypanosomatid genomes, ranging from approximately 18 Mb for Obscuromonas modryi to 35 Mb for Crithidia brevicula and Zelonia costaricensis. Despite being the smallest, the genome of O. modryi has the highest content of repetitive elements, contributing nearly half of its total size. Conversely, the highest proportion of unique DNA is found in the genomes of Wallacemonas spp., with repeats accounting for less than 8% of the assembly length. The majority of examined species exhibit varying degrees of aneuploidy, with trisomy being the most frequently observed condition after disomy.

CONCLUSIONS

The genome of Obscuromonas modryi represents a very unusual, if not unique, example of evolution driven by two antidromous forces: i) increasing dependence on the host leading to genomic shrinkage and ii) expansion of repeats causing genome enlargement. The observed variation in somy within and between trypanosomatid genera suggests that these flagellates are largely predisposed to aneuploidy and, apparently, exploit it to gain a fitness advantage. High heterogeneity in the genome size, repeat content, and variation in chromosome copy numbers in the newly-sequenced species highlight the remarkable genome plasticity exhibited by trypanosomatid flagellates. These new genome assemblies are a robust foundation for future research on the genetic basis of life cycle changes and adaptation to different hosts in the family Trypanosomatidae.

A unique mRNA decapping complex in trypanosomes

Removal of the mRNA 5' cap primes transcripts for degradation and is central for regulating gene expression in eukaryotes. The canonical decapping enzyme Dcp2 is stringently controlled by assembly into a dynamic multi-protein complex together with the 5'-3'exoribonuclease Xrn1. Kinetoplastida lack Dcp2 orthologues but instead rely on the ApaH-like phosphatase ALPH1 for decapping. ALPH1 is composed of a catalytic domain flanked by C- and N-terminal extensions. We show that T. brucei ALPH1 is dimeric in vitro and functions within a complex composed of the trypanosome Xrn1 ortholog XRNA and four proteins unique to Kinetoplastida, including two RNA-binding proteins and a CMGC-family protein kinase. All ALPH1-associated proteins share a unique and dynamic localization to a structure at the posterior pole of the cell, anterior to the microtubule plus ends. XRNA affinity capture in T. cruzi recapitulates this interaction network. The ALPH1 N-terminus is not required for viability in culture, but essential for posterior pole localization. The C-terminus, in contrast, is required for localization to all RNA granule types, as well as for dimerization and interactions with XRNA and the CMGC kinase, suggesting possible regulatory mechanisms. Most significantly, the trypanosome decapping complex has a unique composition, differentiating the process from opisthokonts.

Decoding the impact of nuclear organization on antigenic variation in parasites

Antigenic variation as a strategy to evade the host adaptive immune response has evolved in divergent pathogens. Antigenic variation involves restricted, and often mutually exclusive, expression of dominant antigens and a periodic switch in antigen expression during infection. In eukaryotes, nuclear compartmentalization, including three-dimensional folding of the genome and physical separation of proteins in compartments or condensates, regulates mutually exclusive gene expression and chromosomal translocations. In this Review, we discuss the impact of nuclear organization on antigenic variation in the protozoan pathogens Trypanosoma brucei and Plasmodium falciparum. In particular, we highlight the relevance of nuclear organization in both mutually exclusive antigen expression and genome stability, which underlie antigenic variation.

Implementation evaluation of mhealth interventions in the secondary prevention of coronary artery disease: a supplementary review

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): La Trobe University

Introduction

mHealth technologies have evolved rapidly in recent years and are now widely implemented for the secondary prevention of coronary artery disease (CAD). While there is increasing evidence of their effectiveness, there are significant knowledge gaps concerning their reach, adoption, implementation, and maintenance.

Purpose

This study evaluates internal and external validity dimensions of mHealth-enabled cardiac disease management programs (DMPs) using elements of Glasgow’s RE-AIM (Reach-Effectiveness-Adoption-Implementation-Maintenance) Framework. It is a supplementary review to a systematic review and meta-analysis which evaluated effectiveness.

Methods

From the 27 studies reviewed for the previous systematic review on effectiveness, a citation search was performed to identify additional publications reporting on elements of reach, adoption, implementation, and maintenance. All eligible publications were independently coded by two team members using the 23-item RE-AIM extraction tool and analysed using mixed-methods to ascertain the reporting of these elements.

Results

In total, 35 publications were included in the analysis, 27 from the previous systematic review and 8 supplementary publications. The items for the Reach dimension indicated participant participation rates ranging between 18% to 67%, and used a wide range of exclusion criteria, relating to mental and cognitive impairment (37%), physical impairments (41%) and language issues (26%). Most (44%) interventions were solely home-based with nurses being the main health professionals delivering the intervention (adoption items). The implementation and maintenance items showed intervention duration of between 4-52 weeks (median 24 weeks) with intervention follow-up of between 1-48 months (median 6 months).

Conclusions

This review found great heterogeneity in the duration and follow-up of mHealth-enabled DMPs for patients with CAD, with low participation rates suggesting access barriers. Addressing RE-AIM dimensions in the evaluation of mHealth-enabled cardiac DMPs for patients with CAD is critically important for identifying factors affecting the reach, adoption, implementation, and maintenance of interventions in order to improve translation of research evidence into practice for patients, clinicians and health service organisations.

Cohort profile: the ESC EURObservational Research Programme Non-ST-segment elevation myocardial infraction (NSTEMI) Registry

AIMS

The European Society of Cardiology (ESC) EURObservational Research Programme (EORP) Non-ST-segment elevation myocardial infarction (NSTEMI) Registry aims to identify international patterns in NSTEMI management in clinical practice and outcomes against the 2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without ST-segment-elevation.

METHODS AND RESULTS

Consecutively hospitalised adult NSTEMI patients (n = 3620) were enrolled between 11 March 2019 and 6 March 2021, and individual patient data prospectively collected at 287 centres in 59 participating countries during a two-week enrolment period per centre. The registry collected data relating to baseline characteristics, major outcomes (in-hospital death, acute heart failure, cardiogenic shock, bleeding, stroke/transient ischaemic attack, and 30-day mortality) and guideline-recommended NSTEMI care interventions: electrocardiogram pre- or in-hospital, pre-hospitalization receipt of aspirin, echocardiography, coronary angiography, referral to cardiac rehabilitation, smoking cessation advice, dietary advice, and prescription on discharge of aspirin, P2Y12 inhibition, angiotensin converting enzyme inhibitor (ACEi)/angiotensin receptor blocker (ARB), beta-blocker, and statin.

CONCLUSION

The EORP NSTEMI Registry is an international, prospective registry of care and outcomes of patients treated for NSTEMI, which will provide unique insights into the contemporary management of hospitalised NSTEMI patients, compliance with ESC 2015 NSTEMI Guidelines, and identify potential barriers to optimal management of this common clinical presentation associated with significant morbidity and mortality.

Distinct mRNA and protein interactomes highlight functional differentiation of major eIF4F-like complexes from Trypanosoma brucei

Gene expression in pathogenic protozoans of the family Trypanosomatidae has several novel features, including multiple eIF4F-like complexes involved in protein synthesis. The eukaryotic eIF4F complex, formed mainly by eIF4E and eIF4G subunits, is responsible for the canonical selection of mRNAs required for the initiation of mRNA translation. The best-known complexes implicated in translation in trypanosomatids are based on two related pairs of eIF4E and eIF4G subunits (EIF4E3/EIF4G4 and EIF4E4/EIF4G3), whose functional distinctions remain to be fully described. Here, to define interactomes associated with both complexes in Trypanosoma brucei procyclic forms, we performed parallel immunoprecipitation experiments followed by identification of proteins co-precipitated with the four tagged eIF4E and eIF4G subunits. A number of different protein partners, including RNA binding proteins and helicases, specifically co-precipitate with each complex. Highlights with the EIF4E4/EIF4G3 pair include RBP23, PABP1, EIF4AI and the CRK1 kinase. Co-precipitated partners with the EIF4E3/EIF4G4 pair are more diverse and include DRBD2, PABP2 and different zinc-finger proteins and RNA helicases. EIF4E3/EIF4G4 are essential for viability and to better define their role, we further investigated their phenotypes after knockdown. Depletion of either EIF4E3/EIF4G4 mRNAs lead to aberrant morphology with a more direct impact on events associated with cytokinesis. We also sought to identify those mRNAs differentially associated with each complex through CLIP-seq with the two eIF4E subunits. Predominant among EIF4E4-bound transcripts are those encoding ribosomal proteins, absent from those found with EIF4E3, which are generally more diverse. RNAi mediated depletion of EIF4E4, which does not affect proliferation, does not lead to changes in mRNAs or proteins associated with EIF4E3, confirming a lack of redundancy and distinct roles for the two complexes.

Characterization of sudden death etiologies in a Portuguese population younger than 40 years-old

Background

The incidence and pathogenesis of sudden death (SD) in the young adult population in Portugal remains to be clarified. Some of the causes are known to be hereditary and a better understanding of these can have implications on the development of a national screening program for relatives of SD victims.

Purpose

To describe the leading causes of sudden cardiac and non-cardiac death in a young adult Portuguese population (≤40 years-old).

Methods

The authors retrospectively reviewed cases from a national database regarding individuals who underwent an autopsy, between 2012 and 2016, at 6 districts of mainland Portugal plus the islands. All young adults (1–40 years-old) who had a sudden unexpected death were included and violent deaths were excluded. This study was approved by the Institute Ethics Committee. We reviewed the autopsy files and collected demographic, clinical, necropsic, anatomopathological and toxicological data from each case. We performed statistical analysis using Stata 13.0 software.

Results

During a 5-year period, out of an estimated total of 2101 deaths in ages 1 to 40, 175 SD were identified. SD victims had a mean age of 32±9 years-old, the majority being of male gender (69%,n=120). There were 115 (66%) cases of SD of confirmed cardiac origin (see Table 1). The remaining causes were respiratory (18%), cerebral (7%), digestive (6%), endocrinologic (2%), urinary (1%), infectious (1%). The most frequent cardiac cause being coronary atherosclerosis (n=40,35%), which included lesions with estimated luminal narrowing >75% and/or documented type 1 acute myocardial infarction. These patients were older (31±8 vs 35±4, p<0.020), had a minimum age of 26 years, and more frequently male (85% vs 61%, p=0.011). There were 17 (15%) victims who had cardiopathy with histopathological hypertrophy (5 of them with associated fibrosis), and the diagnosis of hypertrophic cardiomyopathy (HCM) was possible in only 3 (3%) victims. In addition, there were 15 (13%) who died from pulmonary embolism who were predominantly women (23% vs 80%, p<0.001). There were 8 (7%) victims with a final diagnosis of cardiopathy with histopathological dilation, 2 possibly corresponding to post-partum cardiomyopathy (CMP), 1 to ethanolic CMP and 1 to ventricular dilation and fibrosis due to previous myocarditis, who had associated hepatitis with signs of activity. Six cases of acute myocarditis were identified, who were significantly younger, comparing to patients dying from other cardiac causes (23±13 vs 33±7, p=0,011). There were 2 cases of HCM with genetic data, one of which was complemented during molecular autopsy.

Conclusions

During a 5-year period, the cumulative incidence of SD in a region of Portugal is very low (n=175), cardiac causes being present in 66% of the cases. The most frequent cardiac cause is coronary atherosclerosis (35%).

Funding Acknowledgement

Type of funding sources: None.

Pre-discharge B-lines at bedside predicts 30-day and multiple 90-day hospital re-admission in patients admitted for acute decompensated heart failure

Background

Inadequate decongestion at index admission for Acute Decompensation of Heart Failure (ADHF) is a common cause of adverse outcomes. A bedside 9-zone Lung and IVC ultrasound assessment (LUICA) may help to guide decongestion and reduce hospital readmission or mortality.

Purpose

To identify predictors of multiple 90-day hospital representations or mortality based on a bedside handheld 9-zone LUICA volume assessment obtained by HF nurses.

Methods

Patients admitted for ADHF, enrolled in the RISK-HF registry and undergoing pre-discharge LUICA, were assessed for 90-day readmission and/or mortality. The primary outcome of this observational report was prediction of multiple hospital representations based on pre-discharge volume status. The LUICA was performed with a hand-held ultrasound (HHU) device (Lumify, Philips) by trained HF-nurses. Functional capacity was measured with Duke Activity Status Index (DASI). Paired t-tests were used to compare mean differences. Logistic and linear regression were used to study relationships of outcomes with clinical characteristics. Cox regression was used to analyse time to repeated readmission or death. Analysis conducted with SPSS statistics V27 and STATA SE16.

Results

Of 302 ADHF patients, 67 readmitted within 30-days (age 76±8.5; men, 60%; HFrEF; 44%) and 235 did not readmit within 30-days (age 72±14; 57% men; 52% HFrEF). Readmission occurred in older patients (p=0.05), with pre-discharge signs of residual congestion that was based on the number of b-lines (p<0.01) (Table 1). Pre-discharge B-lines were predictive of DAOOH (β −0.41, −0.6, −0.22, p<0.01) and of multiple 90-day hospital readmissions (β 0.03, 0.018, 0.05, p<0.01), independently of 30-day event risk score, number of readmissions the preceding 12 months and age at index admission (Table 2). Number of B-lines at discharge was also associated with repeated readmission or death (HR=1.02 [1.01, 1.04]) in time-to-event analysis, independent of any other factors.

Conclusion

Pre-discharge residual congestion defined by the number B-lines increases the likelihood of multiple 90-day adverse outcomes.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): The University of MelbourneBaker Heart & Diabetes Institute

Invariant surface glycoprotein 65 of Trypanosoma brucei is a complement C3 receptor

African trypanosomes are extracellular pathogens of mammals and are exposed to the adaptive and innate immune systems. Trypanosomes evade the adaptive immune response through antigenic variation, but little is known about how they interact with components of the innate immune response, including complement. Here we demonstrate that an invariant surface glycoprotein, ISG65, is a receptor for complement component 3 (C3). We show how ISG65 binds to the thioester domain of C3b. We also show that C3 contributes to control of trypanosomes during early infection in a mouse model and provide evidence that ISG65 is involved in reducing trypanosome susceptibility to C3-mediated clearance. Deposition of C3b on pathogen surfaces, such as trypanosomes, is a central point in activation of the complement system. In ISG65, trypanosomes have evolved a C3 receptor which diminishes the downstream effects of C3 deposition on the control of infection.

Trypanosomes evade the immune response through antigenic variation of a surface coat containing variant surface glycoproteins (VSG). They also express invariant surface glycoproteins (ISGs), which are less well understood. Here, Macleod et al. show that ISG65 of T. brucei is a receptor for complement component 3. They provide the crystal structure of T. brucei ISG65 in complex with complement C3d and show evidence that ISG65 is involved in reducing trypanosome susceptibility to C3-mediated clearance in vivo.

Molecular detection of novel Anaplasma sp . and zoonotic hemopathogens in livestock and their hematophagous biting keds (genus Hippobosca) from Laisamis, northern Kenya

Background: Livestock are key sources of livelihood among pastoral communities. Livestock productivity is chiefly constrained by pests and diseases. Due to inadequate disease surveillance in northern Kenya, little is known about pathogens circulating within livestock and the role of livestock-associated biting keds (genus Hippobosca) in disease transmission. We aimed to identify the prevalence of selected hemopathogens in livestock and their associated blood-feeding keds. Methods: We randomly collected 389 blood samples from goats (245), sheep (108), and donkeys (36), as well as 235 keds from both goats and sheep (116), donkeys (11), and dogs (108) in Laisamis, Marsabit County, northern Kenya. We screened all samples for selected hemopathogens by high-resolution melting (HRM) analysis and sequencing of PCR products amplified using primers specific to the genera: Anaplasma, Trypanosoma, Clostridium, Ehrlichia, Brucella, Theileria, and Babesia. Results: In goats, we detected Anaplasma ovis (84.5%), a novel Anaplasma sp. (11.8%), Trypanosoma vivax (7.3%), Ehrlichia canis (66.1%), and Theileria ovis (0.8%). We also detected A. ovis (93.5%), E. canis (22.2%), and T. ovis (38.9%) in sheep. In donkeys, we detected ' Candidatus Anaplasma camelii' (11.1%), T. vivax (22.2%), E. canis (25%), and Theileria equi (13.9%). In addition, keds carried the following pathogens; goat/sheep keds - T. vivax (29.3%) , Trypanosoma evansi (0.86%), Trypanosoma godfreyi (0.86%), and E. canis (51.7%); donkey keds - T. vivax (18.2%) and E. canis (63.6%); and dog keds - T. vivax (15.7%), T. evansi (0.9%), Trypanosoma simiae (0.9%) , E. canis (76%), Clostridium perfringens (46.3%), Bartonella schoenbuchensis (76%), and Brucella abortus (5.6%). Conclusions: We found that livestock and their associated ectoparasitic biting keds carry a number of infectious hemopathogens, including the zoonotic B. abortus. Dog keds harbored the most pathogens, suggesting dogs, which closely interact with livestock and humans, as key reservoirs of diseases in Laisamis. These findings can guide policy makers in disease control.

A longitudinal two-year survey of the prevalence of trypanosomes in domestic cattle in Ghana by massively parallel sequencing of barcoded amplicons

Background

Animal African Trypanosomiasis (AAT) is one of the most economically important diseases affecting livestock productivity in sub-Saharan Africa. The disease is caused by a broad range of Trypanosoma spp., infecting both wild and domesticated animals through cyclical and mechanical transmission. This study aimed to characterize trypanosomes present in cattle at regular intervals over two years in an AAT endemic and a non-endemic region of Ghana.

Methodology/Principal findings

Groups of cattle at Accra and Adidome were selected based on their geographical location, tsetse fly density, prevalence of trypanosomiasis and the breed of cattle available. Blood for DNA extraction was collected at approximately four to five-week intervals over a two-year period. Trypanosome DNA were detected by a sensitive nested PCR targeting the tubulin gene array and massively parallel sequencing of barcoded amplicons. Analysis of the data was a semi-quantitative estimation of infection levels using read counts obtained from the sequencing as a proxy for infection levels. Majority of the cattle were infected with multiple species most of the time [190/259 (73%) at Adidome and 191/324 (59%) at Accra], with T. vivax being the most abundant. The level of infection and in particular T. vivax, was higher in Adidome, the location with a high density of tsetse flies. The infection level varied over the time course, the timings of this variation were not consistent and in Adidome it appeared to be independent of prophylactic treatment for trypanosome infection. Effect of gender or breed on infection levels was insignificant.

Conclusions/Significance

Most cattle were infected with low levels of several trypanosome species at both study sites, with T. vivax being the most abundant. The measurements of infection over time provided insight to the importance of the approach in identifying cattle that could suppress trypanosome infection over an extended time and may serve as reservoir.

Cattle are of economic importance in sub-Saharan Africa as they fulfil multiple roles, ranging from draught power, to providing manure, milk, and meat. However, Animal African Trypanosomiasis (AAT) diseases in cattle affect productivity and food security in most African countries. In Ghana, bovine trypanosomiasis has been detected in few cross-sectional studies by molecular methods. To get a better understanding of the disease, a longitudinal study showing natural trypanosome infection over the life of cattle will be applicable. To explore this issue, the study determined the nature of trypanosome infection in cattle in farm settings in Ghana over two years, a period similar to that used in beef production, by massively parallel amplicon sequencing. The study provided a description of the prevalence over two years and showed that the cattle were infected with multiply species most of the time and the level of infection varied but was low most of the time. The longitudinal study allowed the identification of one individual able to supress infection far more effectively than other members of the herd and this is crucial in implementing control measures in the infected area.

Black-necked spitting cobra (Naja nigricollis) phospholipases A2 may cause Trypanosoma brucei death by blocking endocytosis through the flagellar pocket

African trypanosomes, such as Trypanosoma brucei, are flagellated protozoa which proliferate in mammals and cause a variety of diseases in people and animals. In a mammalian host, the external face of the African trypanosome plasma membrane is covered by a densely packed coat formed of variant surface glycoprotein (VSG), which counteracts the host's adaptive immune response by antigenic variation. The VSG is attached to the external face of the plasma membrane by covalent attachment of the C-terminus to glycosylphosphatidylinositol. As the trypanosome grows, newly synthesised VSG is added to the plasma membrane by vesicle fusion to the flagellar pocket, the sole location of exo- and endocytosis. Snake venoms contain dozens of components, including proteases and phospholipases A2. Here, we investigated the effect of Naja nigricollis venom on T. brucei with the aim of describing the response of the trypanosome to hydrolytic attack on the VSG. We found no evidence for VSG hydrolysis, however, N. nigricollis venom caused: (i) an enlargement of the flagellar pocket, (ii) the Rab11 positive endosomal compartments to adopt an abnormal dispersed localisation, and (iii) cell cycle arrest prior to cytokinesis. Our results indicate that a single protein family, the phospholipases A2 present in N. nigricollis venom, may be necessary and sufficient for the effects. This study provides new molecular insight into T. brucei biology and possibly describes mechanisms that could be exploited for T. brucei targeting.

Identification of sequence-specific promoters driving polycistronic transcription initiation by RNA polymerase II in trypanosomes

Protein-coding genes in trypanosomes occur in polycistronic transcription units (PTUs). How RNA polymerase II (Pol II) initiates transcription of PTUs has not been resolved; the current model favors chromatin modifications inducing transcription rather than sequence-specific promoters. Here, we uncover core promoters by functional characterization of Pol II peaks identified by chromatin immunoprecipitation sequencing (ChIP-seq). Two distinct promoters are located between divergent PTUs, each driving unidirectional transcription. Detailed analysis identifies a 75-bp promoter that is necessary and sufficient to drive full reporter expression and contains functional motifs. Analysis of further promoters suggests transcription initiation is regulated and promoters are either focused or dispersed. In contrast to the previous model of unregulated and promoter-independent transcription initiation, we find that sequence-specific promoters determine the initiation of Pol II transcription of protein-coding genes PTUs. These findings in Trypanosoma brucei suggest that in addition of chromatin modifications, promoter motifs-based regulation of gene expression is deeply conserved among eukaryotes.

Characterization and quality of care indicators in patients with acute myocardial infarction without ST segment elevation

Introduction

The definition of the quality of care in healthcare services is paramount to implement the resources necessary to grant the best quality of care according to the current guidelines. Recently, the European Society of Cardiology's guidelines for the management of acute coronary syndromes without ST segment elevation (NSTEMI) were published, and defined the quality indicators to be evaluated in such patients.

Purpose

To characterize the level of care given to the population of patients with NSTEMI included in the a national registry since 2011, according to the new guidelines directives.

Population and methods

We evaluated 12193 patients with NSTEMI. For each year the following variables were analyzed: age, gender, cardiovascular and non-cardiovascular comorbidities, clinical presentation (rhythm, blood pressure, Killip-Kimball Class), left ventricular ejection fraction (LVEF), treatment during admission and discharge, and time to invasive coronary angiography (ICA). Besides this, a comparing between years was made to analyze differences according to the quality indicators established in the guidelines.

Results

In 2019, 83.9% of patient with LVEF <40% were treated with IECA/ARA II and 80.6% were prescribed a betablocker at discharge. No statistically significant differences were found across the year with respect to IECA/ARA II at discharge (p=0.495), and beta-blocker at discharge (p=0.812). In terms of P2Y12 inhibitors during the hospital admission, there was a statistically significant increase in its use when comparing 2019 to 2014, 2015, 2016 and 2017 (p=0.019 for 2014 and p<0,001 the following years), with prescription in 90.4% of the patients in 2019. At discharge 88.3% of the patients were prescribed a P2Y12 inhibitor in 2019 and there was also a statistically significant increase in its prescription when compared to the previous years (from 2011 to 2017 with a p<0.001). When it comes to the prescription of statins at discharge there was a statistically significant difference between groups, driven mostly by an increase compared to the year 2012 (95.6% vs 90.8%, p=0.005). Only 16% of patients were subjected to ICA within 24h of admission during the year 2019. No statistically significant difference was found between other years (p>0.100 when comparing between years).

Discussion

The most striking feature that can be improved is the amount of patients subject to ICA within the first 24h after diagnosis. When it comes to the P2Y12 inhibitors it is also clear that there has been an increase in its prescription during the admission and at discharge. To sum up, it is clear that there is still some margin to improve care, of at least 10–20% in most parameters. This data portrays a picture of the measures and steps to take in order to provide the adequate care according to the latest guidelines.

Funding Acknowledgement

Type of funding sources: None.

Cryoablation: safety of same day discharge

Introduction

Discharge after overnight hospital stay is standard procedure in patients submitted to elective atrial fibrillation (AF) ablation. Taking into consideration the low rate of cryoablation procedure complications could the same day discharge be an option?

Purpose

To assess the safety of same day discharge of patients submitted to AF cryoablation.

Methods

Single-center retrospective study of consecutive patients admitted to elective AF cryoablation in a tertiary center between February 2017 and November 2020. Patients were divided into two groups: same day discharge and next day discharge. Only patients submitted to ablation until 4 p.m. were included. Complication rates were obtained up to six months after the procedure. Complications were defined as death, pericardial tamponade, hematoma requiring evaluation and/or intervention, major bleeding requiring transfusion, hospital admission related to the procedure.

Results

One hundred fifty-four patients were included, with a mean age of 61±10.9 years, 66.2% were males, 18.2% with diabetes, 65.6% with dyslipidemia, 77.9% with hypertension, 10.4% with chronic kidney disease KDIGO stage 3 or more. Median follow-up of 436 [178 – 729] days. Most of the patients had paroxysmal (73.4%) and persistent short duration AF (23.4%). Sixty-two patients (40.3%) were early discharged and there were no differences between the two groups regarding epidemiological and clinical characteristics (p=NS).

A very low rate of complications in both groups was observed, occurring in 6.5% of patients with early discharge and in 8.7% of patients in overnight stay, without statistical significance between the two groups (p=0.61). The most frequent complications were local hematoma (5 patients, 2 in early discharged group), pericardial effusion (3 patients, all in overnight stay), femoral pseudo-aneurism (2 patients, 1 in each group) and arteriovenous fistula (1 patient in overnight stay group). The type of complications did not differ between the two groups (p=0.51). Two patients died during follow up, and this was unrelated to the procedure. In addition, no difference in success rate and arrhythmic recurrence was observed between the two groups (p=NS).

Conclusion

Our study suggests that it is safe to early discharge patients submitted to AF ablation, reducing the hospital stay length in selected patients. Larger studies are needed to confirm this data before routine implementation of this strategy.

Funding Acknowledgement

Type of funding sources: None.

Association of heart failure readmission with results of lung ultrasound at discharge and follow-up

Background

Attainment of euvolemia at discharge and maintaining it after discharge are fundamental to avoiding readmission in heart failure (HF). Lung ultrasound (LUS) is potentially of value to detect congestion but the role of sequential LUS is undefined.

Purpose

To determine the predictive value of discharge and follow-up LUS.

Methods

98 pts (mean age 72.8±12.3, mean ejection fraction 41.4%±18.4, gender male 56%) admitted with HF or fluid overload, underwent pre-discharge LUS to evaluate pulmonary (presence of ≥10 B lines) and peripheral (IVC diameter) congestion. LUS was repeated at home follow-up visits at 2 weeks post-discharge. Associations were sought between pre-discharge and follow-up LUS and 90 day outcomes (readmission or mortality).

Results

Overall, there was an increase in the total number of B-lines from baseline to week 2 [mean change in B-lines 3.82 [95% confidence intervals (CI), 0.30, 7.33) p=0.036] followed by a small decrease between scan 2 and scan 3 [mean change in B-lines −0.25 (95% CI, −0.17, 7.68), p=0.94]. Of 73 with <10 B-lines pre-discharge, 26 (36%) had events by 90 days, compared with 14 of the 25 with ≥10 pre-discharge B-lines (56%, p=0.07). However, all of those with ≥10 B lines at 2 weeks had events, compared with 25% of those with <10 B lines (p=0.04).

Conclusions

Attainment and preservation of euvolemia after index hospitalization for HF is challenging and requires appropriate patient support. Detection of residual congestion, as well as detection of early re-congestion after hospital discharge.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): The University of MelbourneBaker Heart & Diabetes Institute Readmission risk ratio

Efficacy and feasibility of heart failure nurses to deliver a lungs and inferior vena cava ultrasound assessment (LUICA) protocol and prediction of outcomes

Background/Introduction

Congestion is the main cause for hospital admission and readmission in heart failure (HF), with almost half being discharged with symptoms that suggest residual congestion. Novel non-invasive assessments (eg. lung ultrasound; [LUS], and Inferior Vena Cava [IVC]) may be used to assess congestion. A LUs and IvC Assessment (LUICA) delivered by HF nurses before discharge, could detect residual congestion, optimise diuresis and guide post discharge treatment.

Purpose

To determine the ability of HF nurses to successfully learn a LUICA protocol, obtain interpretable images, provide diagnostic reports and predict outcomes.

Methods

A teaching program focused on quantification of congestion by counting B-lines and reporting estimated right atrial pressure (e-RAP) from IVC congestion. LUICA readings were dichotomised based on lung congestion (≥10 vs <10 B-lines), the presence of lung pathology (consolidation, atelectasis, effusion) and IVC congestion (e-RAP >3mmHg vs 3mmHg). LUICA (8 lung zones + 2 IVC zones) was added to pre-discharge review (4 days post-admission) by HF nurses in 108 hospitalised pts (72±13 years; 58% male) with acute HF, fluid overload, and a variety of lung pathology. Images were assessed for quality (good, usable, measurable or not measurable) and interpreted by a LUICA expert and HF nurses, blinded to admission diagnosis. The predictive value of LUICA readings for patient outcomes (readmission or mortality) was expressed as risk ratio.

Results

The quality at the majority of the images was assessed as good or usable (expert: 82/107, nurses: 66/107, p=0.02). Readmission was predicted by both experts and nurses (picture 1).

Conclusions

HF nurses can be adequately trained in a 10 Zone LUICA and successfully obtain interpretable images. The predictive power of their interpretation is similar to experts.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): The University of MelbourneBaker Heart & Diabetes Institute Readmission risk ratio based on LUICA

It is possible to predict mortality after ICD implantation?

Introduction

Implantable Cardioverter Defibrillators (ICD) therapy is not recommended in patients who do not have a reasonable expectation of survival for at least 1 year, although specific recommendations regarding clinical or functional status evaluation are lacking.

Purpose

To identify predictors of all-cause mortality in patients who implanted an ICD.

Methods

Prospective single-center study of patients who implanted ICD between 2015 and 2019. Clinical characteristics were evaluated at baseline and mortality was assessed using the national registry of citizens. We performed uni and multivariate analysis to compare clinical characteristics of patients who died and who survived using Cox regression and Kaplan-Meier methods. For the predictor creatinine, we assessed the discrimination power and the best cut-off using the area under the ROC curve (AUC) method.

Results

From 2015–2019, 414 ICDs were implanted (81% male, 62±12 years-old), and 50 (13%) of the patients died after a median follow-up of 23 [11–41] months. Patients who died during the follow-up were older (67±9 vs 61±12, p=0.002), had more diabetes (48% vs 33%, p=0.033) and a higher creatinine (1.23 [0.84–1.86] vs 1.00 [0.84–1.22], p<0.001). The remaining comorbidities were similar between groups (Fig. 1). Patients who died had more frequently an ICD implanted after complication associated with a previous device or as a pacemaker upgrade (6% vs 2%, p=0.030). They also had a higher frequency of ischaemic cardiomyopathy (i-CMP) (82% vs 56%, p=0.002) and of ejection fraction (EF) ≤50% (96% vs 82%, p=0.040). The best cut-off value of creatinine to predict mortality with a sensitivity of 65% and a specificity of 72% was 1.2mg/dl (AUC 0.650; CI95% 0.53–0.77). After adjusting for diabetes, i-CMP, EF ≤50% and upgrade/re-implantation after complication, we found that age (HR 1.033; 95% CI 1.00–1.06, p=0.041) and creatinine ≥1.2mg/dl (HR 2.134; 95% CI 1.09–4.19, p=0.028) were independent predictors of all-cause mortality.

Conclusion

In our cohort of patients who underwent ICD implantation for primary or secondary sudden cardiac death prevention, the all-cause mortality over a median follow-up period of 23 [11–41] months was 13%. We found that in addition to age, a baseline creatinine level ≥1.2mg/dl increases by 2-fold mortality in patients who undergo ICD implantation. Decisions regarding ICD candidacy should not be based on age alone but should also consider creatinine that predisposes to mortality despite ICD implantation.

Funding Acknowledgement

Type of funding sources: None. All cause mortality

Transmission of 'Candidatus Anaplasma camelii' to mice and rabbits by camel-specific keds, Hippobosca camelina

Anaplasmosis, caused by infection with bacteria of the genus Anaplasma, is an important veterinary and zoonotic disease. Transmission by ticks has been characterized but little is known about non-tick vectors of livestock anaplasmosis. This study investigated the presence of Anaplasma spp. in camels in northern Kenya and whether the hematophagous camel ked, Hippobosca camelina, acts as a vector. Camels (n = 976) and > 10,000 keds were sampled over a three-year study period and the presence of Anaplasma species was determined by PCR-based assays targeting the Anaplasmataceae 16S rRNA gene. Camels were infected by a single species of Anaplasma, 'Candidatus Anaplasma camelii', with infection rates ranging from 63-78% during the dry (September 2017), wet (June-July 2018), and late wet seasons (July-August 2019). 10-29% of camel keds harbored 'Ca. Anaplasma camelii' acquired from infected camels during blood feeding. We determined that Anaplasma-positive camel keds could transmit 'Ca. Anaplasma camelii' to mice and rabbits via blood-feeding. We show competence in pathogen transmission and subsequent infection in mice and rabbits by microscopic observation in blood smears and by PCR. Transmission of 'Ca. Anaplasma camelii' to mice (8-47%) and rabbits (25%) occurred readily after ked bites. Hence, we demonstrate, for the first time, the potential of H. camelina as a vector of anaplasmosis. This key finding provides the rationale for establishing ked control programmes for improvement of livestock and human health.

Cardiac magnetic resonance evaluation of takotsubo cardiomyopathy

Funding Acknowledgements

Type of funding sources: None.

Introduction

Takotsubo Cardiomyopathy(TCM)is a reversible pathology with clinical features practically indistinguishable from AMI.Cardiac magnetic resonance(CMR)is uniquely suited in differentiating TCM from other forms of acute ventricular dysfunction.CMR can also identify potential complications.

Purpose

The aim of this study was to characterize TCM features,as well as to evaluate diagnostic and prognostic impact of CMR in these patients.

Methods

A 7-years prospective study,which included patients of our center proposed to CMR with presumptive diagnosis of MINOCA based on acute chest pain,troponin raise and absence of angiographically significant coronary disease (luminal stenosis <50%).We analysed clinical characteristics, electrocardiograms, echo and coronariography.A presumptive diagnosis was elaborated and comparison was made with the TCM definitive one after CMR.We applied a protocol to evaluate TCM patients’ left and right ventricles(LV;RV)both anatomically and functionally, and search for late gadolinium enhancement(LGE).

Results

A total of 93 patients were evaluated,of which 16 had the final diagnosis of TCM.Takotsubo-cardiomyopathy patients were all female,with a mean age of 69 ± 14years old.At admission,75% had ST segment elevation, so emergent coronariography was performed. The median highest troponin I was 2,235[1,30-4,27]ng/mL.CMR confirmed 25%(n = 4) of presumptive diagnosis of TCM. On the other 75%initial diagnosis was changed to TCM after CMR:50%(n = 6) and 17%(n = 2)of patients had an initial presumptive diagnoses of reperfunded STEMI and NSTEMI,respectively. In 33% the initial diagnosis was myocarditis.From CMR evaluation of TCM patients, left atrial dilation was found in 31%(mean indexed area 18 ± 1,5cm2/m2).A majority (81%) presented with preserved ejection fraction(EF)(mean LV EF 59 ± 10%).Regional contractility abnormalities were described in 19%,being hypokinesia in all mid and apical segments in 2 cases, and diffuse in one.LV dysfunction was present in 13%(mean LV EF 32 ± 2%) and RV"s in 2cases (mean RV EF 42%),with only one with biventricular EF depression.Mean LV end diastolic indexed volume(EDIV)was 72 ± 23mL/m2,with only 2 with LV dilation(LV EDIV 120 ± 7mL/m2),non had dilated RV.Mild pericardial effusion was found in 38%,mild mitral regurgitation in 8patients and moderate in 1.A complication was registered:LV outflow tract protomesossystolic acceleration with mild anterior leaflet prolapse,without SAM.No LV thrombus was identified.LGE was observed in 2(13%)of patients:in one it was found on the apex,on the other one the pattern was linear intramyocardial on mid segment of inferior septum.

Conclusion

CMR provides a noninvasive and multidimensional assessment for evaluation of Takotsubo cardiomyopathy.In our population,performing CMR allowed an initial diagnosis modification in 3/4 of the cases and identification of one complication,both with therapeutic and prognostic implications.

Cardiac Magnetic Resonance as a diagnostic tool in arrhythmias

Funding Acknowledgements

Type of funding sources: None.

Introduction

Etiology of cardiac arrhythmias is often difficult to determine.As the gold standard to anatomical and functional cardiac evaluation,Cardiac Magnetic Resonance(CMR)can be a fundamental technique for accurate assessment of myocardial arrhythmic substrates or for arrhythmias management.

Purpose

The aim of this study is to determine diagnostic and arrhythmic risk stratification impact of CMR performed in patients with suspected or confirmed arrhythmias.

Methods

We performed a six-years prospective study of patients with suspected or confirmed arrhythmias which evaluation with other techniques did not provide a definitive diagnosis.These patients underwent CMR for diagnostic and risk stratification assessment.We applied a protocol to evaluate both ventricles’ morphology and functional and late gadolinium enhancement (LGE) presence.

Results

A total of 93 patients were included,of which 66% were male, with a mean age of 45 ± 17 years old. The indications for patients with suspected or confirmed arrhythmias performing CMR evaluation were the following: 33% (n = 31) of the patients had very frequent premature ventricular complexes, 23% (n = 21) had sustained ventricular tachycardia (VT), 5%(n = 5) non-sustained VT, 17%(n = 16) suspected structural heart disease with high arrhythmic potential,10%(n = 9) unexplained recurrent syncope,9 %(n = 8) supraventricular tachycardia and 3% (n = 3) aborted sudden cardiac death. Depressed ejection fraction (EF)(<50%) was present in 10% (n = 9) for LV(mean EF 38 ± 9%) and 15%(n = 14) for RV (mean EF 42 ± 7%). Dilation of LV was found in 25% of patients (n = 23, mean LV volume: 115 ± 7ml/m²), with RV dilation being present in only 1 patient, who had right ventricle arrhythmogenic dysplasia (RVAD) (RV volume: 152ml/m²). In total, 16%had interventricular septum hypertrophy (mean 15 ± 4mm/m2).We found slight anterior leaflet prolapse of mitral valve in 10% (n = 9) of the cases and mild mitral regurgitation in 15% (n = 14). Left atrium dilation was observed in 17% (n = 16) of patients (mean area of 18 ± 2cm2/m2), as right atrium was dilated in only two. In 20% of the patients, CMR contributed to establish a previously unknown diagnosis: 6% (n = 5) have hypertrophic cardiomyopathy,4%(n = 4)a myocarditis sequelae and 2%(n = 2)had RVAD. LV non-compaction,a silent myocardial infarction scar and non-ischemic dilated cardiomyopathy were diagnosed in 3%of the cases each. In 15%(n = 14)we found nonspecific variations, which deserve follow-up. On the remaining patients, CMR was considered normal.

Conclusion

 As a high reproducible, accurate and versatile technique, CMR allowed an increase on diagnosis in 20% of the patients with suspected or confirmed arrhythmias. Consequently, it contributed to the risk stratification of our study population with suspected high arrhythmic potential when the first-line complementary exams were inconclusive.

Sequential production of gametes during meiosis in trypanosomes

Meiosis is a core feature of eukaryotes that occurs in all major groups, including the early diverging excavates. In this group, meiosis and production of haploid gametes have been described in the pathogenic protist, Trypanosoma brucei, and mating occurs in the salivary glands of the insect vector, the tsetse fly. Here, we searched for intermediate meiotic stages among trypanosomes from tsetse salivary glands. Many different cell types were recovered, including trypanosomes in Meiosis I and gametes. Significantly, we found trypanosomes containing three nuclei with a 1:2:1 ratio of DNA contents. Some of these cells were undergoing cytokinesis, yielding a mononucleate gamete and a binucleate cell with a nuclear DNA content ratio of 1:2. This cell subsequently produced three more gametes in two further rounds of division. Expression of the cell fusion protein HAP2 (GCS1) was not confined to gametes, but also extended to meiotic intermediates. We propose a model whereby the two nuclei resulting from Meiosis I undergo asynchronous Meiosis II divisions with sequential production of haploid gametes.

Characterisation of the T-cell response to Ebola virus glycoprotein amongst survivors of the 2013-16 West Africa epidemic

Zaire ebolavirus (EBOV) is a highly pathogenic filovirus which can result in Ebola virus disease (EVD); a serious medical condition that presents as flu like symptoms but then often leads to more serious or fatal outcomes. The 2013-16 West Africa epidemic saw an unparalleled number of cases. Here we show characterisation and identification of T cell epitopes in surviving patients from Guinea to the EBOV glycoprotein. We perform interferon gamma (IFNγ) ELISpot using a glycoprotein peptide library to identify T cell epitopes and determine the CD4+ or CD8+ T cell component response. Additionally, we generate data on the T cell phenotype and measure polyfunctional cytokine secretion by these antigen specific cells. We show candidate peptides able to elicit a T cell response in EBOV survivors and provide inferred human leukocyte antigen (HLA) allele restriction. This data informs on the long-term T cell response to Ebola virus disease and highlights potentially important immunodominant peptides.

VSG mRNA levels are regulated by the production of functional VSG protein

The bloodstream form of Trypanosoma brucei persists in mammalian hosts through a population survival strategy depending on antigenic variation of a cell surface coat composed of the variant surface glycoprotein (VSG). The integrity of the VSG coat is essential and blocking its synthesis results in a cell division cycle arrest just prior to cytokinesis. This observation indicates that VSG levels are monitored and that the cell has mechanisms to respond to a disruption of synthesis. Here, the regulation of VSG mRNA levels has been investigated by first measuring VSG mRNA copy number, and second using ectopic expression of VSG transgenes containing premature termination codons. The findings are that (i) VSG mRNA copy number varies with the identity of the VSG and (ii) a pathway detects synthesis of non-functional VSG protein and results in an increase in VSG mRNA levels.

Searching for the final diagnosis using cardiac magnetic resonance in MINOCA patients

Introduction

In patients with clinical evidence of acute myocardial infarction (AMI), absence of obstructive coronary disease does not imply absence of acute thrombotic process. Thereafter, it can be designated as Myocardial Infarction with Non-obstructive Coronary Arteries (MINOCA). In these cases, performing Cardiac Magnetic Resonance (CMR) can be essential for establishing a final diagnosis, due to evaluation of the presence and pattern of late enhancement.

Purpose

The aim of this study is to evaluate the diagnostic and prognostic impact of cardiac magnetic resonance in patients with a possible diagnosis of MINOCA.

Methods

A 7-years prospective study in our centre, which included all patients proposed to CMR with a presumptive diagnosis of MINOCA due to acute chest pain, troponin raise and absence of angiographically significant coronary disease (luminal stenosis of <50%). All patients performed functional, anatomical evaluation, as so late gadolinium enhancement search. We analysed clinical characteristics, electrocardiographic presentation, echocardiographic and coronariography results. A presumptive diagnosis was elaborated after coronariography and comparison was made with the definitive one after CMR.

Results

A total of 85 patients were included, 53% were male, with a mean age of 49±20 years old. Clinical history of hypertension was observed in 52% patients, 34% had dyslipidaemia, 8% with diabetes, obesity was present in 21% of patients and smoking habits in 33%. At admission, 47% had ST segment elevation, so emergent coronariography was performed. The mean highest troponin I was 7,54±9,39ng/mL. Late gadolinium enhancement was observed in 50 (59%) of patients. After CMR realization a final diagnosis of MINOCA was made in only 13 patients (15%) and in 51 patients (60%) CMR evaluation allowed a diagnosis modification, with impact on patients' management and prognosis. Of these 51 patients, a definitive diagnosis of myocarditis was seen in 65% of cases, of Takotsubo's myocardiopathy in 27%, and hypertrophic cardiomyopathy in 8%. In 21 (25%) of patients, late gadolinium enhancement was not found. However its absence could exclude type 1 AMI as definitive diagnosis.

Conclusion

CMR is a fundamental technique on MINOCA patients' management. In our population, performing CMR allowed initial diagnosis modification in about two thirds of the cases, with important therapeutic and prognostic implications.

Funding Acknowledgement

Type of funding source: None

Cardiogenic shock without severe left ventricular dysfunction after acute myocardial infarction: population characterization and impact in prognosis

Introduction

Traditionally, severe left ventricular dysfunction is assumed to be the main predictor of CS afte acute myocardial infarction (AMI), however trials and registries show that in average left ventricular function is only moderately depressed in CS after acute myocardial infarction.

Purpose

To characterize the population of patients (Pts) with CS after AMI but without severe left ventricular dysfunction (defined as ejection fraction >30%) and assess their impact in mortality.

Methods

From a national multicenter registry, we evaluated 16332 Pts with AMI and ejection fraction (EF) >30%. We considered 2 groups: Group 1 – Pts who developed CS and Group 2 – Pts who didn't developed CS. We registered age, gender, cardiovascular and non-cardiovascular co-morbidities, electrocardiographic presentation and coronary anatomy. We also evaluated the following in-hospital complications: Re-Infarction, mechanical complications, high-grade atrial ventricular block, sustained ventricular tachycardia (VT) atrial fibrillation (AF) and stroke. We compared the in-hospital mortality.

Results

The presence of CS without severe left ventricular dysfunction was observed in 3,2% pts (n=518) with AMI, being CS present at admission in 46,8% of these pts. The mean EF was lower in group 1 pts (44% ± 11 vs 53±11%, p<0,001). Patients in group 1 were older (71±13 vs 65±13 years, p<0,001), more females (38,8% vs 26,6%, p<0,001), had a higher prevalence of previous valvular heart disease (6,1% vs 3,0%, p<0,001), heart failure (10,1% vs 4,8%, p<0,001, peripheral artery disease (7,5% vs 5,3%, p=0,03), chronic kidney disease (9,8% vs 5,4%, p<0,001), chronic pulmonary obstructive disease (9,1% vs 4,9%, p<0,001) and previous stroke (11,0% vs 7,2%, p<0,001). At admission, Group 1 pts had more ST-elevation AMI (72,6% vs 43,0%, p<0,001), more AF (11,4% vs 6,6%, p<0,001) and more right bundle block (9,9%% vs 5,8%, p<0,001). Group 1 patients received less coronary angiography (80,9% vs 88,2%, p<0,00. The presence of multivessel disease (64,3% vs 51,4%, p<0,001), left main disease (12,2% vs 7,2%, p<0,001), left anterior descending disease (72,4% vs 64,3%, p<0,001) and right coronary disease (64,8% vs 55,5%, p<0,001) were more prevalent in Group 1 pts. Group 1 pts had more in-hospital complications: Re-Infarction (4,4% vs 0,9%, p<0,001), AF (23,0% vs 4,3%, p<0,001), mechanical complications (8,9% vs 0,3%, p<0,001), high atrial ventricular block (21,9% vs 2,3%, p<0,001), VT (10,8% vs 1,2%, p<0,001) and major bleeding (8,9% vs 1,3%, p<0,001). In-hospital mortality was also much higher in Group 1 pts (29,5% vs 1,2%, p<0,001).

Conclusions

Cardiogenic shock is present in 3,2% of AMI pts without severe ventricular dysfunction. These pts were older, more frequent female, had higher morbidities and in-hospital complications. Even without severe ventricular dysfunction, cardiogenic shock in these patients was associated with a much higher in-hospital mortality.

Funding Acknowledgement

Type of funding source: None

Modified zwolle score with delta-creatinine: enhancing the safety of early discharge after STEMI

Introduction

The Zwolle score (ZS) is recommended to identify low-risk patients eligible for early discharge after acute ST-segment elevation myocardial infarction (STEMI), but as only one-third of STEMIs have a low ZS, the discharge is often postponed. Creatinine variation (Δ-Cr) also provide prognostic information after STEMI.

Purpose

The authors intend to study the “modified Zwolle Score” (MZS) model, which encompasses Δ-Cr as a variable that may enhance the discriminative power of the standard ZS. The outcome is 30-day mortality, time range that starts right after the ACS.

Methods

This is a retrospective study with data from a national multicentre registry. We have included 3.296 patients with STEMI. Zwolle score was calculated for each patient. It is defined as shown in figure 1.

Δ-Cr was defined as maximum serum creatinine minus admission serum creatinine. A Δ-Cr≥0.3 was assigned 2 points in the Modified Zwolle Score, after interpretation of odds ratio via multivariate analysis.

For prediction quality assessment, we have performed ROC curve analysis with both scoring systems versus 30-day mortality. Regarding survival analysis, we have performed Kaplan-Meier curves with Log-rank analysis. We have also registered complications during hospital stay.

Results

The sample mean age is 63±14, and it is composed by 76.8% of males. The majority of patients presented Killip Class I (87.3%). The STEMI was anterior in 49.7% of patients and inferior in 49.8% of patients. The mean admission time was 5 days. Intrahospital mortality was 3% and 30-day mortality was 4%.

The mean ZS was 3.1±2.8 points, the mean MZS was 3±2.1 points and the mean Δ-Cr was 0.2±0.6mg/dL.

The ROC curve analysis between ZS and early mortality revealed a c-statistic of 0.810 (CI 0.796–0.823), whereas the ROC curve between MZS and early mortality revealed a c-statistic of 0.853 (95% CI: 0.841–0.865). The ROC curves comparison showed superiority of the MZS c-statistic, with a difference between AUC of 0.043 (p<0.001, 95% CI: 0.024–0.063).

Regarding low-risk patients, 30-day mortality was 3.3% using ZS (0–2 points) and 2.4% using modified ZS (0–2 points). Fifty patients (1.5%) died between 3rd and 10th day after ACS: original ZS low-risk criteria registered 0.09% and modified ZS low-risk criteria 0.06% fatalities. Kappa coefficient for intergroup concordance was good (0.73).

Conclusion

We conclude that by adding Δ-Cr to the standard ZS, a renal function parameter that was lacking in the ZS, its predicting capacity regarding early mortality in patients admitted with STEMI was increased. Comparing both scores, low-risk patients defined by MZS registered less complications, 3–10 day mortality and 30-day mortality than low-risk patients defined by the original ZS. This fact may lead to better distinction of patients who will benefit from early discharge.

Zwolle Score, ROC curves and survival

Funding Acknowledgement

Type of funding source: None

Non Type-1 Brugada pattern, diagnostic yield of 5 ECG criteria in a young adult cohort

Introduction

Distinguishing between non-Type 1 Brugada pattern (non-T1BrP) and an athlete's ECG remains challenging and may have important prognostic implications. We aimed to study prevalence and the diagnostic yield of experts and non-experts for the electrocardiographic non-T1BrP criteria in the young adults from the Sudden Cardiac Death-Screening Of risk factorS (SCD-SOS) cohort.

Methods

We performed a cross-sectional study in which we reviewed 14662 ECGs of SCD-SOS survey participants and selected 2494 that presented a rSr'-pattern in V1-V2. Among these, 98 were classified by experts in hereditary arrhythmic syndromes for the presence of non-T1BrP and by non-experts who performed manual measurements of the diagnostic criteria based on triangle formed by r'-wave. We estimated intra and interobserver concordance for each criterion, and used logistic regression and receiver operating characteristics (ROC) analysis and C-statistics for diagnostic accuracy and definition of the most appropriate cut-off values.

Results

We detected a rSr'-pattern in V1-V2 in 17% of the individuals and found that it was associated with higher PQ and QTc intervals, male gender and lower BMI. The manual measurements of non-T1BrP criteria were reproducible: we had high intraobserver concordance coefficients (CC) ranging from 0.90 to 0.94 (except for d(B) that had 0.66), but interobserver CC were lower (0.45–0.68). The measurements performed were highly correlated with non-T1BrP diagnosis and the criteria with higher discriminatory capacity were the distance d(B) (AUC 0.77; 95% CI0.69–0.84) and the degree of ST-ascent (AUC 0.79; 95% CI 0.72–0.86). The cut-offs defined by other authors had very low sensitivity (8–12%), despite high specificity (98%), so we defined new cut-offs: d(A) ≥2mm, d(B) ≥1.25mm, d(B)/h ≥0.38, β-angle ≥19° and ST-ascent ≥1mm. The addition of the degree of ST-ascent to a model with these 4 parameters presented an increase in C-statistics from 0.77 (95% CI: 0.68–0.86) to 0.83 (95% CI: 0.75–0.91) for the diagnosis of non-T1BrP by an expert in Sudden Arrhythmic Death and Channelopathies.

Conclusion

A rSr'-pattern in precordial leads V1-V2 is a frequent finding and the detection of non-T1BrP by using the aforementioned 5 measurements is reproducible and accurate. In this study, we describe new cut-off values that may help untrained clinicians to identify young individuals who should be referred for provocative drug testing for Brugada Syndrome.

Accuracy of non-T1 BrP criteria

Funding Acknowledgement

Type of funding source: None

On-Site Ribosome Remodeling by Locally Synthesized Ribosomal Proteins in Axons

Ribosome assembly occurs mainly in the nucleolus, yet recent studies have revealed robust enrichment and translation of mRNAs encoding many ribosomal proteins (RPs) in axons, far away from neuronal cell bodies. Here, we report a physical and functional interaction between locally synthesized RPs and ribosomes in the axon. We show that axonal RP translation is regulated through a sequence motif, CUIC, that forms an RNA-loop structure in the region immediately upstream of the initiation codon. Using imaging and subcellular proteomics techniques, we show that RPs synthesized in axons join axonal ribosomes in a nucleolus-independent fashion. Inhibition of axonal CUIC-regulated RP translation decreases local translation activity and reduces axon branching in the developing brain, revealing the physiological relevance of axonal RP synthesis in vivo. These results suggest that axonal translation supplies cytoplasmic RPs to maintain/modify local ribosomal function far from the nucleolus in neurons.

Positively selected modifications in the pore of TbAQP2 allow pentamidine to enter Trypanosoma brucei

Mutations in the Trypanosoma brucei aquaporin AQP2 are associated with resistance to pentamidine and melarsoprol. We show that TbAQP2 but not TbAQP3 was positively selected for increased pore size from a common ancestor aquaporin. We demonstrate that TbAQP2’s unique architecture permits pentamidine permeation through its central pore and show how specific mutations in highly conserved motifs affect drug permeation. Introduction of key TbAQP2 amino acids into TbAQP3 renders the latter permeable to pentamidine. Molecular dynamics demonstrates that permeation by dicationic pentamidine is energetically favourable in TbAQP2, driven by the membrane potential, although aquaporins are normally strictly impermeable for ionic species. We also identify the structural determinants that make pentamidine a permeant although most other diamidine drugs are excluded. Our results have wide-ranging implications for optimising antitrypanosomal drugs and averting cross-resistance. Moreover, these new insights in aquaporin permeation may allow the pharmacological exploitation of other members of this ubiquitous gene family.

African sleeping sickness is a potentially deadly illness caused by the parasite Trypanosoma brucei. The disease is treatable, but many of the current treatments are old and are becoming increasingly ineffective. For instance, resistance is growing against pentamidine, a drug used in the early stages in the disease, as well as against melarsoprol, which is deployed when the infection has progressed to the brain. Usually, cases resistant to pentamidine are also resistant to melarsoprol, but it is still unclear why, as the drugs are chemically unrelated.

Studies have shown that changes in a water channel called aquaglyceroporin 2 (TbAQP2) contribute to drug resistance in African sleeping sickness; this suggests that it plays a role in allowing drugs to kill the parasite. This molecular ‘drain pipe’ extends through the surface of T. brucei, and should allow only water and a molecule called glycerol in and out of the cell. In particular, the channel should be too narrow to allow pentamidine or melarsoprol to pass through. One possibility is that, in T. brucei, the TbAQP2 channel is abnormally wide compared to other members of its family. Alternatively, pentamidine and melarsoprol may only bind to TbAQP2, and then ‘hitch a ride’ when the protein is taken into the parasite as part of the natural cycle of surface protein replacement.

Alghamdi et al. aimed to tease out these hypotheses. Computer models of the structure of the protein were paired with engineered changes in the key areas of the channel to show that, in T. brucei, TbAQP2 provides a much broader gateway into the cell than observed for similar proteins. In addition, genetic analysis showed that this version of TbAQP2 has been actively selected for during the evolution process of T. brucei. This suggests that the parasite somehow benefits from this wider aquaglyceroporin variant.

This is a new resistance mechanism, and it is possible that aquaglyceroporins are also larger than expected in other infectious microbes. The work by Alghamdi et al. therefore provides insight into how other germs may become resistant to drugs.

Erratum to "The cell surface - A new journal for transkingdom cell wall research" [Cell Surface 1 (2018) 1]

[This corrects the article DOI: 10.1016/j.tcsw.2017.05.001.].

Prevalence and correlates of normal body mass index central obesity among people with cardiovascular diseases in Australia

OBJECTIVE

Obesity is one of the most common risk factors for cardiometabolic diseases in Australia and worldwide. Recent studies show that people with normal body mass index (BMI) but with central obesity are at increased risk of morbidity and mortality from cardiometabolic diseases. This risk has not been explained well. The aim of this study was to examine the magnitude, correlates and effects of normal BMI central obesity in the Australian adult population.

STUDY DESIGN

Longitudinal study with data linkage.

METHODS

We used the Baker Biobank, which contains sociodemographic, behavioural, clinical and mortality data. Data were collected between 2000 and 2011 from 6530 adults who were between 18 and 69 years of age. Biobank data were linked to the National Death Index. A matrix of BMI and waist-to-height ratio (WHtR) and waist-to-hip ratio (WHR) were used to create adiposity categories. For analysis, we used descriptive statistics, logistic regression and cox regression models.

RESULTS

The overall prevalence of normal BMI central obesity was 13.4% by WHtR and 14.4% by WHR. Gender, age, BMI and physical activity were associated with normal BMI central obesity. Higher odds of multimorbidity and increased hazards of all-cause and cardiovascular mortality were associated with WHR.

CONCLUSION

WHtR and WHR, when each used with BMI, provided similar estimates of prevalence of normal BMI central obesity. However, WHR is a better predictor of all-cause and cardiovascular mortality.

Sugammadex: routine use vs restrictive use

Worldwide, the use of sugammadex for the reversal of neuromuscular blocking agents worldwide is restricted. This article reflects on how more liberal use of sugammadex might alter patient experience, anaesthetic delivery and surgical techniques.

Detection of blood pathogens in camels and their associated ectoparasitic camel biting keds, Hippobosca camelina: the potential application of keds in xenodiagnosis of camel haemopathogens

Background: Major constraints to camel production include pests and diseases. In northern Kenya, little information is available about blood-borne pathogens circulating in one-humped camels ( Camelus dromedarius) or their possible transmission by the camel haematophagous ectoparasite, Hippobosca camelina, commonly known as camel ked or camel fly. This study aimed to: (i) identify the presence of potentially insect-vectored pathogens in camels and camel keds, and (ii) assess the potential utility of keds for xenodiagnosis of camel pathogens that they may not vector.

Methods: In Laisamis, northern Kenya, camel blood samples (n = 249) and camel keds (n = 117) were randomly collected from camels. All samples were screened for trypanosomal and camelpox DNA by PCR, and for Anaplasma, Ehrlichia, Brucella, Coxiella, Theileria, and Babesia by PCR coupled with high-resolution melting (PCR-HRM) analysis.

Results: In camels, we detected Trypanosoma vivax (41%), Trypanosoma evansi (1.2%), and “ Candidatus Anaplasma camelii” (68.67%). In camel keds, we also detected T. vivax (45.3%), T. evansi (2.56%), Trypanosoma melophagium (1/117) (0.4%), and “ Candidatus Anaplasma camelii” (16.24 %). Piroplasms ( Theileria spp. and Babesia spp.), Coxiella burnetii, Brucella spp., Ehrlichia spp., and camel pox were not detected in any samples.

Conclusions: This study reveals the presence of epizootic pathogens in camels from northern Kenya. Furthermore, the presence of the same pathogens in camels and in keds collected from sampled camels suggests the potential use of these flies in xenodiagnosis of haemopathogens circulating in camels.

Detection of blood pathogens in camels and their associated ectoparasitic camel biting keds, Hippobosca camelina: the potential application of keds in xenodiagnosis of camel haemopathogens

Background: Major constraints to camel production include pests and diseases. In northern Kenya, little information is available about blood-borne pathogens circulating in one-humped camels ( Camelus dromedarius) or their possible transmission by the camel haematophagous ectoparasite, Hippobosca camelina, commonly known as camel ked or camel fly. This study aimed to: (i) identify the presence of potentially insect-vectored pathogens in camels and camel keds, and (ii) assess the potential utility of keds for xenodiagnosis of camel pathogens that they may not vector. Methods: In Laisamis, northern Kenya, camel blood samples (n = 249) and camel keds (n = 117) were randomly collected from camels. All samples were screened for trypanosomal and camelpox DNA by PCR, and for Anaplasma, Ehrlichia, Brucella, Coxiella, Theileria, and Babesia by PCR coupled with high-resolution melting (PCR-HRM) analysis. Results: In camels, we detected Trypanosoma vivax (41%), Trypanosoma evansi (1.2%), and " Candidatus Anaplasma camelii" (68.67%). In camel keds, we also detected T. vivax (45.3%), T. evansi (2.56%), Trypanosoma melophagium (1/117) (0.4%), and " Candidatus Anaplasma camelii" (16.24 %). Piroplasms ( Theileria spp. and Babesia spp.), Coxiella burnetii, Brucella spp., Ehrlichia spp., and camel pox were not detected in any samples. Conclusions: This study reveals the presence of epizootic pathogens in camels from northern Kenya. Furthermore, the presence of the same pathogens in camels and in keds collected from sampled camels suggests the potential use of these flies in xenodiagnosis of haemopathogens circulating in camels.

A receptor for the complement regulator factor H increases transmission of trypanosomes to tsetse flies

Persistent pathogens have evolved to avoid elimination by the mammalian immune system including mechanisms to evade complement. Infections with African trypanosomes can persist for years and cause human and animal disease throughout sub-Saharan Africa. It is not known how trypanosomes limit the action of the alternative complement pathway. Here we identify an African trypanosome receptor for mammalian factor H, a negative regulator of the alternative pathway. Structural studies show how the receptor binds ligand, leaving inhibitory domains of factor H free to inactivate complement C3b deposited on the trypanosome surface. Receptor expression is highest in developmental stages transmitted to the tsetse fly vector and those exposed to blood meals in the tsetse gut. Receptor gene deletion reduced tsetse infection, identifying this receptor as a virulence factor for transmission. This demonstrates how a pathogen evolved a molecular mechanism to increase transmission to an insect vector by exploitation of a mammalian complement regulator.

475 A rare cause of right ventricular mass

Introduction

Intracardiac masses are always a challenging diagnosis, especially when it involves the right side of the heart. There are multiples etiologies that can be responsible for these masses, namely thrombosis, neoplasm or vegetations. Occasionally, these may be related to an autoimmune process not yet discovered.

Case Report

17-year-old male, with a previous history of genital ulcers, medicated with penicillin with complete resolution of symptoms.

In January 2019, he started an history of recurrent fever, associated with right anterior thoracalgia, weight loss and oral afthosis. He went to the emergency department several times, where he was medicated with antibiotic, with partial symptom relief.

Three months later, he returned to medical attention due to an episode of abundant hemoptysis, followed by hematemesis and cough. At hospital admission, he was hemodynamically stable, tachycardic (100/min) and with occasional episodes of cough. Cardiac and pulmonary auscultation were unremarkable. Thoracic CT revealed the presence of pulmonary thromboembolism (PTE) and a large mass in the right ventricle (RV). It was performed an echocardiogram (echo) that confirmed the presence of a large mass in the RV (50x53mm) from which a projecting hypermobile mass appeared to prolapse into the right atrium.

Taking into account the diagnosis of PTE and the presence of a right ventricular mass, the patient was hospitalized and started anticoagulation. The case was immediately discussed with cardiac surgery, that confirmed that there was no surgical indication. During hospitalization, there were no more episodes of hemoptysis or hematemesis.Consecutive echos were performed, that did not reveal a significant decrease in mass dimensions despite anticoagulation. Viral serologies and autoimmunity panel were all negative. Cardiac RMI was performed raising the suspicion of a possible mass covered with thrombus.

After discussion with rheumatology, and according to clinical signs, the hypothesis of vasculitis was placed, and the patient started treatment with steroids. This treatment had to be suspended after a few days due to an infectious intercurrence. After a course of antibiotic therapy, the patient started therapy with cyclophosphamide with good clinical and echocardiographic response (reduced mass dimensions).

It was admitted Behçet’s disease with cardiac complications, and the patient was referred to the rheumatology consultation.

Conclusion

Behçet’s disease is a multi-system, chronic disorder that behaves like vasculitis.There are some typical clinical manifestations associated with this disease, such as oral and genital afthosis, uveitis, arthritis, skin lesions and nervous system involvement.Presentations with cardiac symptoms are one of the extremely rare manifestations of this disease, posing a challenge for the treating physician.

Abstract 475 Figure. Right ventricular mass

P1461 Concomitant potential cardioembolic sources in a patient with an acute ischemia of the limb

Introduction

Transesophageal echocardiography (TEE) is the gold standard exam to look for a cardioembolic source in a patient with an otherwise unexplained suspected systemic ischemic event. Purpose: This clinical case aims to illustrate the importance of a thorough TEE evaluation in the presence of a suspected systemic emboli, and to not neglect thoracic aorta evaluation when a potential intracardiac cause has been detected. Case presentation: We present the case of a 55-year-old man, obese (BMI 30kg/m2), active smoker, with no past medical history or medication, and whose father died from an unspecified cardiovascular cause at 45 years-old. He was admitted to the hospital because of an acute ischemia of the right lower limb, for which he underwent urgent percutaneous femoral embolectomy of the limb, with success. During hospitalization, he was referred for a TEE, which showed valves and cavities with no evidence of potential embolic sources. However, he had a thin and hypermobile atrial septum, with no obvious defect after color flow mapping, but with a patent foramen oval (PFO) that was detected after agitated saline injection associated with a Valsalva maneuver, with the passage of 5-25 microbubbles (grade 2/4 shunt) and an atrial septum aneurysm (ASA), with an excursion of the fossa ovalis towards the left atrium of 10.1mm (Figure 1). The ascending aorta was normal, but the descending aorta depicted 2 hypermobile masses, 1 starting at 35cm from the dental arch (transversal area: 0,52cm2), the longest (7cm) starting at 32cm and ending at the aortic arch (transversal area: 1,76cm2). An angio-CT was immediately performed, which depicted an atheromatous calcified plaque in the terminal portion of the aortic arch, giving rise to the image suggestive of thrombus, and extending for about 6cm to the medium third of the descending thoracic aorta. The remaining portions of the aorta and iliac arteries depicted diffuse atheromatous and partially calcified plaques (Figure 2). The patient was submitted to an urgent thoracic endovascular aortic repair with a 26x10cm prosthesis implantation with occlusion of the left subclavian artery and an adequate final clinical result. Syphilis and auto-immune disease were excluded and a diffuse atheromatous disease of the aorta was assumed as the cause of the thrombus and the embolic event. After 16 days, he was discharged asymptomatic and with no signs of chronic ischemia, treated with oral anticoagulation with rivaroxabano, high-dose statin and strict smoking cessation. Conclusion: Cardioembolic source is a heterogeneous entity. In this patient, 2 potential cardioembolic sources were detected: while the PFO and ASA are minor or unclear risk sources of emboli, TEE also allowed for the detection of a large thrombus arising from an atherosclerotic calcified plaque in the thoracic aorta, which was considered a major risk source, thus implying urgent surgery to obviate the risk of further embolic events.

Abstract P1461 Figure. Fig.1.POF and ASA;Fig.2.Aortic Thrombus

P260 Left ventricular pseudoaneurysm manifesting as syncope

Introduction

Left ventricular (LV) pseudoaneurysms form when cardiac rupture is contained by adherent pericardium or scar tissue. LV pseudoaneurysm is one of the mechanical complications of myocardial infarctions (MI), particularly inferior wall MI.

Although LV pseudoaneurysms are not common, the diagnosis is difficult and they are prone to rupture. Transthoracic echocardiography is commonly used in clinical practice and is usually sufficient to make the diagnosis of LV pseudoaneurysm. Regardless of treatment, patients with LV pseudoaneurysms had a high mortality rate, especially those who did not undergo surgery.

Description of the clinical case

74 years-old woman, with previous history of hypertension, dyslipidaemia and type 2 diabetes and stable coronary disease. In June 2018 the patient underwent coronary angiography that revealed left main and 3 vessels coronary disease, Cardiac revascularization surgery was proposed that the patient refused. The patient was stable during 6 months. Four days before presenting to emergency department the patient mentioned intermittent pre-cordial pain associated with exertion. At admission day she felt intense pre-cordial pain, accompanied by sudoresis and nausea, relieving with sublingual nitrate. The patient was hemodynamically stable at admission. Electrocardiogram showed sinus rhythm 65 bpm with 2mm ST-elevation of inferior leads. Troponin I was positive 30 ng/dL. Echocardiogram revealed marked hypokinesia of inferior and lateral wall with moderate depression of global systolic function ans presence of slight circumferential pericardial effusion (6mm in diastole on lateral wall)

Emergent coronariography was performed and revealed progression of coronary disease of the right coronary artery with sub-occlusion of the mid segment. Cardiac revascularization surgery was proposed and the patient accepted this time. Echocardiogram was repeated during hospitalization revealed a stable pericardial effusion with reduced dimension comparing to admission. After 3 weeks, while waiting surgery in the ward, the patient was a syncope that resulted in fracture of the distal peroneum. Ecocardiogram was performed and revealed a LV posterior wall pseudoaneurysm through a narrow neck in parasternal long axis view and the presence of large pericardial effusion (Fig 1). The patient was submitted to definitive reparative cardiac surgery with pericardium patch and coronary artery bypass graft from left internal mammary to anterior descending coronary artery. The patient recovered well from the cardiac surgery and at 2 months follow up is alive and without signs of heart failure.

This case illustrates the complexity in the management of patients with LV pseudoaneurysm. These patients require substantial critical care, imaging and surgical expertise.

A high clinical index of suspicion is needed to avoid missing the diagnosis LV pseudoaneurysm and transthoracic echocardiography is essential to establish the diagnosis.

Abstract P260 Figure. Fig 1 - LV pseudoaneurysm

Structure of the trypanosome transferrin receptor reveals mechanisms of ligand recognition and immune evasion

To maintain prolonged infection of mammals, African trypanosomes have evolved remarkable surface coats and a system of antigenic variation1. Within these coats are receptors for macromolecular nutrients such as transferrin2,3. These must be accessible to their ligands but must not confer susceptibility to immunoglobulin-mediated attack. Trypanosomes have a wide host range and their receptors must also bind ligands from diverse species. To understand how these requirements are achieved, in the context of transferrin uptake, we determined the structure of a Trypanosoma brucei transferrin receptor in complex with human transferrin, showing how this heterodimeric receptor presents a large asymmetric ligand-binding platform. The trypanosome genome contains a family of around 14 transferrin receptors4, which has been proposed to allow binding to transferrin from different mammalian hosts5,6. However, we find that a single receptor can bind transferrin from a broad range of mammals, indicating that receptor variation is unlikely to be necessary for promiscuity of host infection. In contrast, polymorphic sites and N-linked glycans are preferentially found in exposed positions on the receptor surface, not contacting transferrin, suggesting that transferrin receptor diversification is driven by a need for antigenic variation in the receptor to prolong survival in a host.

P1722A new predictive score for mortality and cardiogenic shock in patients with ST-elevation myocardial infarction

Introduction

Acute Myocardial Infarction with ST elevation (STEMI) presents a high rate of potentially fatal complications and in-hospital mortality.

Objective

To test the predictive capacity for Cardiogenic Shock (CS) and In-hospital Mortality (MIH) of a new risk score in patients (Pts) with STEMI.

Population and methods

Evaluated 5765 Pts with STEMI without CS at admission. The new score, was derived by previous studies in this population, and was calculated according to the following criteria: age ≥65 years (1 point), heart rate ≥100bpm (2 points), systolic blood pressure <100mmHg (2 points), blood glucose at admission above 180 mg/dL (1 point) and creatinine at admission >1.5mg/dL (2 points). The population was divided into three subgroups: group A low score (0–2 points), group B intermediate score (3–5 points) and group C score (6–8 points). The endpoints defined were CS during hospitalization, in-hospital mortality and combined end-point of MIH and CS. The relationship between each of the possible scores (from 0 to 8) and the various end-points was determined, and the sensitivity and specificity of the score as a predictor of MIH and CS was defined as the area under the ROC curve (ASC).

Results

After the application of the score, 3 subgroups were obtained: group A with 4819 Pts (83,6%), group B with 884 Pts (15,3%) and group C 62 Pts (1,1%). Patients of group C had a higher MIH (Group C: 45,2% vs B: 11,4% vs A: 2,0%, p<0,001), higher CS (C: 29,5% vs B: 12,0% vs A: 2,3%, p<0,001) and a higher combined end-point of MIH and CC (C: 53,2% vs B: 17,8% vs A: 3,4%, p<0,001) during hospitalization. The proposed score revealed a high predictive capacity of MIH (ASC 0,802, 95% CI 0,775–0,830, p=0,001), of CS (ASC 0,763, 95% CI 0,731–0,795, p=0,001) and for the combined endpoint (MIH and CC) ASC 0,781, 95% CI 0,756–0,806, p=0,001). The logistic regression models showed that Pts with a high score (group C) presented a 41-fold higher risk of MIH (OR 41,3; p<0,001) and 18-fold higher CS (OR 18,0; p<0.001) than patients with low score (group A). It was also found that the risk associated with an increase in one point score unit was 100% (OR 2,0 p<0.001) for MIH and 82% (OR 1,82, p<0,001) for CS.

Conclusion

This new score, with the use of practical and friendly variables, demonstrated a high predictive capacity of MIH and CS.