Concordance between a gastrointestinal consultant radiologist, a consultant radiologist and qualified reporting radiographers interpreting abdominal radiographs

INTRODUCTION

Radiographers can accurately report musculoskeletal and chest radiographs, but there is paucity of research comparing the performance of reporting radiographers (RRs) with consultant radiologists when interpreting and reporting abdominal radiographs. This study assessed interobserver agreement in the clinical setting between reporting radiographers and a consultant radiologist compared to an expert gastrointestinal radiologist in a District General Hospital. Major discordant reports affecting patient management were also examined.

METHODS

126 abdominal radiographs reported by 3 RRs in clinical practice were randomly selected and reported by a consultant radiologist and index gastrointestinal radiologist. The reports of the RRs and consultant radiologist were compared against the reports made by the index radiologist for agreement by a colorectal consultant surgeon. All 126 reports were scored as being in either complete agreement, minor disagreement or major disagreement which would have resulted in a change to patient management.

RESULTS

There was no significant difference in overall agreement between the consultant radiologist (CR) and RRs when compared to the index radiologist (CR: n = 90/126, 71.4% and RRs: n = 94/126, 74.6%. p = 0.57). Major disagreements were found, but there was no significant difference between both groups (CR: n = 23/126, 18.3% and RRs: n = 17/126, 13.5%. p = 0.30).

CONCLUSION

RRs can report abdominal radiographs to a comparable level of agreement as a consultant radiologist in the clinical setting. There was no significant difference in reports deemed to affect patient management.

IMPLICATIONS FOR PRACTICE

This study addresses the gap in assessing the performance of RRs reporting abdominal radiographs. This small scale study indicates that radiographers could provide additional support in the reporting of abdominal radiographs. This would help to reduce radiologist workload and enhance the role of the reporting radiographer.

CLASSIFICATION

Agreement between reporting radiographers and radiologists interpreting and reporting abdominal radiographs.

Select Streptococci Can Degrade Candida Mannan To Facilitate Growth

Multiple studies have found that streptococci have a synergistic relationship with Candida species, but the details of these interactions are still being discovered. Candida species are covered by mannan, a polymer of mannose, which could serve as a carbon source for certain microbes. We hypothesized that streptococci that possess mannan-degrading glycosyl hydrolases would be able to enzymatically cleave mannose residues, which could serve as a primary carbohydrate source to support growth. We analyzed 90 streptococcus genomes to predict the capability of streptococci to transport and utilize mannose and to degrade diverse mannose linkages found on mannan. The genome analysis revealed mannose transporters and downstream pathways in most streptococci, but only <50% of streptococci harbored the glycosyl hydrolases required for mannan degradation. To confirm the ability of streptococci to use mannose or mannan, we grew 6 representative streptococci in a chemically defined medium lacking glucose supplemented with mannose, yeast extract, or purified mannan isolated from Candida and Saccharomyces strains. Although all tested Streptococcus strains could use mannose, Streptococcus salivarius and Streptococcus agalactiae, which did not possess mannan-degrading glycosyl hydrolases, could not use yeast extract or mannan to enhance their growth. In contrast, we found that Streptococcus mitis, Streptococcus parasanguinis, Streptococcus sanguinis, and Streptococcus pyogenes possessed the necessary glycosyl hydrolases to use yeast extract and isolated mannan, which promoted robust growth. Our data indicate that several streptococci are capable of degrading fungal mannans and harvesting mannose for energy. IMPORTANCE This work highlights a previously undescribed aspect of streptococcal Candida interactions. Our work identifies that certain streptococci possess the enzymes required to degrade mannan, and through this mechanism, they can release mannose residues from the cell wall of fungal species and use them as a nutrient source. We speculate that streptococci that can degrade fungal mannan may have a competitive advantage for colonization. This finding has broad implications for human health, as streptococci and Candida are found at multiple body sites.

DCHS1, Lix1L, and the Septin Cytoskeleton: Molecular and Developmental Etiology of Mitral Valve Prolapse

Mitral valve prolapse (MVP) is a common cardiac valve disease that often progresses to serious secondary complications requiring surgery. MVP manifests as extracellular matrix disorganization and biomechanically incompetent tissues in the adult setting. However, MVP has recently been shown to have a developmental basis, as multiple causal genes expressed during embryonic development have been identified. Disease phenotypes have been observed in mouse models with human MVP mutations as early as birth. This study focuses on the developmental function of DCHS1, one of the first genes to be shown as causal in multiple families with non-syndromic MVP. By using various biochemical techniques as well as mouse and cell culture models, we demonstrate a unique link between DCHS1-based cell adhesions and the septin-actin cytoskeleton through interactions with cytoplasmic protein Lix1-Like (LIX1L). This DCHS1-LIX1L-SEPT9 axis interacts with and promotes filamentous actin organization to direct cell-ECM alignment and valve tissue shape.

Mitral Valve Prolapse Induces Regionalized Myocardial Fibrosis

Background Mitral valve prolapse (MVP) is one of the most common forms of cardiac valve disease and affects 2% to 3% of the population. Previous imaging reports have indicated that myocardial fibrosis is common in MVP and described its association with sudden cardiac death. These data combined with evidence for postrepair ventricular dysfunction in surgical patients with MVP support a link between fibrosis and MVP. Methods and Results We performed histopathologic analysis of left ventricular (LV) biopsies from peripapillary regions, inferobasal LV wall and apex on surgical patients with MVP, as well as in a mouse model of human MVP (Dzip1S14R/+). Tension-dependent molecular pathways were subsequently assessed using both computational modeling and cyclical stretch of primary human cardiac fibroblasts in vitro. Histopathology of LV biopsies revealed regionalized fibrosis in the peripapillary myocardium that correlated with increased macrophages and myofibroblasts. The MVP mouse model exhibited similar regional increases in collagen deposition that progress over time. As observed in the patient biopsies, increased macrophages and myofibroblasts were observed in fibrotic areas within the murine heart. Computational modeling revealed tension-dependent profibrotic cellular and molecular responses consistent with fibrosis locations related to valve-induced stress. These simulations also identified mechanosensing primary cilia as involved in profibrotic pathways, which was validated in vitro and in human biopsies. Finally, in vitro stretching of primary human cardiac fibroblasts showed that stretch directly activates profibrotic pathways and increases extracellular matrix protein production. Conclusions The presence of prominent regional LV fibrosis in patients and mice with MVP supports a relationship between MVP and progressive damaging effects on LV structure before overt alterations in cardiac function. The regionalized molecular and cellular changes suggest a reactive response of the papillary and inferobasal myocardium to increased chordal tension from a prolapsing valve. These studies raise the question whether surgical intervention on patients with MVP should occur earlier than indicated by current guidelines to prevent advanced LV fibrosis and potentially reduce residual risk of LV dysfunction and sudden cardiac death.

DZIP1 regulates mammalian cardiac valve development through a Cby1-β-catenin mechanism

Background

Mitral valve prolapse (MVP) is a common and progressive cardiovascular disease with developmental origins. How developmental errors contribute to disease pathogenesis are not well understood.

Results

A multimeric complex was identified that consists of the MVP gene Dzip1, Cby1, and β‐catenin. Co‐expression during valve development revealed overlap at the basal body of the primary cilia. Biochemical studies revealed a DZIP1 peptide required for stabilization of the complex and suppression of β‐catenin activities. Decoy peptides generated against this interaction motif altered nuclear vs cytosolic levels of β‐catenin with effects on transcriptional activity. A mutation within this domain was identified in a family with inherited non‐syndromic MVP. This novel mutation and our previously identified DZIP1^S24R variant resulted in reduced DZIP1 and CBY1 stability and increased β‐catenin activities. The β‐catenin target gene, MMP2 was up‐regulated in the Dzip1^S14R/+ valves and correlated with loss of collagenous ECM matrix and myxomatous phenotype.

Conclusion

Dzip1 functions to restrain β‐catenin signaling through a CBY1 linker during cardiac development. Loss of these interactions results in increased nuclear β‐catenin/Lef1 and excess MMP2 production, which correlates with developmental and postnatal changes in ECM and generation of a myxomatous phenotype.

PDGFRα: Expression and Function during Mitral Valve Morphogenesis

Mitral valve prolapse (MVP) is a common form of valve disease and can lead to serious secondary complications. The recent identification of MVP causal mutations in primary cilia-related genes has prompted the investigation of cilia-mediated mechanisms of disease inception. Here, we investigate the role of platelet-derived growth factor receptor-alpha (PDGFRα), a receptor known to be present on the primary cilium, during valve development using genetically modified mice, biochemical assays, and high-resolution microscopy. While PDGFRα is expressed throughout the ciliated valve interstitium early in development, its expression becomes restricted on the valve endocardium by birth and through adulthood. Conditional ablation of Pdgfra with Nfatc1-enhancer Cre led to significantly enlarged and hypercellular anterior leaflets with disrupted endothelial adhesions, activated ERK1/2, and a dysregulated extracellular matrix. In vitro culture experiments confirmed a role in suppressing ERK1/2 activation while promoting AKT phosphorylation. These data suggest that PDGFRα functions to suppress mesenchymal transformation and disease phenotypes by stabilizing the valve endocardium through an AKT/ERK pathway.

Dynamic Expression Profiles of β-Catenin during Murine Cardiac Valve Development

β-catenin has been widely studied in many animal and organ systems across evolution, and gain or loss of function has been linked to a number of human diseases. Yet fundamental knowledge regarding its protein expression and localization remains poorly described. Thus, we sought to define whether there was a temporal and cell-specific regulation of β-catenin activities that correlate with distinct cardiac morphological events. Our findings indicate that activated nuclear β-catenin is primarily evident early in gestation. As development proceeds, nuclear β-catenin is down-regulated and becomes restricted to the membrane in a subset of cardiac progenitor cells. After birth, little β-catenin is detected in the heart. The co-expression of β-catenin with its main transcriptional co-factor, Lef1, revealed that Lef1 and β-catenin expression domains do not extensively overlap in the cardiac valves. These data indicate mutually exclusive roles for Lef1 and β-catenin in most cardiac cell types during development. Additionally, these data indicate diverse functions for β-catenin within the nucleus and membrane depending on cell type and gestational timing. Cardiovascular studies should take into careful consideration both nuclear and membrane β-catenin functions and their potential contributions to cardiac development and disease.

Primary cilia defects causing mitral valve prolapse

Mitral valve prolapse (MVP) affects 1 in 40 people and is the most common indication for mitral valve surgery. MVP can cause arrhythmias, heart failure, and sudden cardiac death, and to date, the causes of this disease are poorly understood. We now demonstrate that defects in primary cilia genes and their regulated pathways can cause MVP in familial and sporadic nonsyndromic MVP cases. Our expression studies and genetic ablation experiments confirmed a role for primary cilia in regulating ECM deposition during cardiac development. Loss of primary cilia during development resulted in progressive myxomatous degeneration and profound mitral valve pathology in the adult setting. Analysis of a large family with inherited, autosomal dominant nonsyndromic MVP identified a deleterious missense mutation in a cilia gene, DZIP1 A mouse model harboring this variant confirmed the pathogenicity of this mutation and revealed impaired ciliogenesis during development, which progressed to adult myxomatous valve disease and functional MVP. Relevance of primary cilia in common forms of MVP was tested using pathway enrichment in a large population of patients with MVP and controls from previously generated genome-wide association studies (GWAS), which confirmed the involvement of primary cilia genes in MVP. Together, our studies establish a developmental basis for MVP through altered cilia-dependent regulation of ECM and suggest that defects in primary cilia genes can be causative to disease phenotype in some patients with MVP.

Desert hedgehog-primary cilia cross talk shapes mitral valve tissue by organizing smooth muscle actin

Non-syndromic mitral valve prolapse (MVP) is the most common heart valve disease affecting 2.4% of the population. Recent studies have identified genetic defects in primary cilia as causative to MVP, although the mechanism of their action is currently unknown. Using a series of gene inactivation approaches, we define a paracrine mechanism by which endocardially-expressed Desert Hedgehog (DHH) activates primary cilia signaling on neighboring valve interstitial cells. High-resolution imaging and functional assays show that DHH de-represses smoothened at the primary cilia, resulting in kinase activation of RAC1 through the RAC1-GEF, TIAM1. Activation of this non-canonical hedgehog pathway stimulates α-smooth actin organization and ECM remodeling. Genetic or pharmacological perturbation of this pathway results in enlarged valves that progress to a myxomatous phenotype, similar to valves seen in MVP patients. These data identify a potential molecular origin for MVP as well as establish a paracrine DHH-primary cilium cross-talk mechanism that is likely applicable across developmental tissue types.

P2797Clinical outcomes of an ultra-thin strut sirolimus-eluting stent with biodegradable polymer in all-comers patients undergoing coronary intervention

Background

Thin stent struts may be associated with reduced vessel injury and use of biodegradable polymers may further improve long term outcomes. However, data with earlier stents has been inconsistent; thus further studies with newer devices are needed.

Purpose

To evaluate the efficacy and safety of a new ultra-thin (65um) strut cobalt chromium sirolimus-eluting stent with a hybrid design (closed cell at ends and open cells in middle to reduce edge injury and optimise conformability) in all-comers patients undergoing percutaneous coronary intervention (PCI).

Methods

We enrolled 752 patients from 14 sites undergoing PCI into a prospective, non-randomised, multi-centre, open-label, observational registry. Inclusion of patients with complex anatomy (long stent lengths, bifurcations and chronic total occlusions) was encouraged. Clinical follow-up was scheduled at 1, 9, 12 and 24 months. The primary endpoint was incidence of major adverse cardiac events (MACE) - cardiac death, non-fatal myocardial infarction (MI), or target vessel revascularization (TVR) - at 9 months.

Results

Mean patient age was 64.7±12.2 years, 20.7% had diabetes, 58.8% had dyslipidaemia, 40.4% had multi-vessel disease, 22% had previous PCI, 4.7% had previous coronary-artery bypass graft, and 19.6% had a clinical history of previous MI. Mean lesion length was 25.7±17.3 mm. The primary endpoint of cumulative MACE up to 9 months (from 624 patients reaching 9 months follow-up) occurred in 12 patients (1.92%), including 6 (0.96%) cardiac death, 5 (0.80%) MI and 6 (0.96%) clinically indicated TVR. Definite stent thrombosis was reported in 3 patients (0.48%) and probable stent thrombosis in 2 patients (0.32%).

Conclusions

Use of an ultra-thin strut biodegradable polymer sirolimus-eluting stent in all-comers patients undergoing PCI was associated with good clinical efficacy and safety.

Acknowledgement/Funding

Meril Life

Defects in the Exocyst-Cilia Machinery Cause Bicuspid Aortic Valve Disease and Aortic Stenosis

BACKGROUND

Bicuspid aortic valve (BAV) disease is a congenital defect that affects 0.5% to 1.2% of the population and is associated with comorbidities including ascending aortic dilation and calcific aortic valve stenosis. To date, although a few causal genes have been identified, the genetic basis for the vast majority of BAV cases remains unknown, likely pointing to complex genetic heterogeneity underlying this phenotype. Identifying genetic pathways versus individual gene variants may provide an avenue for uncovering additional BAV causes and consequent comorbidities.

METHODS

We performed genome-wide association Discovery and Replication Studies using cohorts of 2131 patients with BAV and 2728 control patients, respectively, which identified primary cilia genes as associated with the BAV phenotype. Genome-wide association study hits were prioritized based on P value and validated through in vivo loss of function and rescue experiments, 3-dimensional immunohistochemistry, histology, and morphometric analyses during aortic valve morphogenesis and in aged animals in multiple species. Consequences of these genetic perturbations on cilia-dependent pathways were analyzed by Western and immunohistochemistry analyses, and assessment of aortic valve and cardiac function were determined by echocardiography.

RESULTS

Genome-wide association study hits revealed an association between BAV and genetic variation in human primary cilia. The most associated single-nucleotide polymorphisms were identified in or near genes that are important in regulating ciliogenesis through the exocyst, a shuttling complex that chaperones cilia cargo to the membrane. Genetic dismantling of the exocyst resulted in impaired ciliogenesis, disrupted ciliogenic signaling and a spectrum of cardiac defects in zebrafish, and aortic valve defects including BAV, valvular stenosis, and valvular calcification in murine models.

CONCLUSIONS

These data support the exocyst as required for normal ciliogenesis during aortic valve morphogenesis and implicate disruption of ciliogenesis and its downstream pathways as contributory to BAV and associated comorbidities in humans.

Filamin-A as a Balance between Erk/Smad Activities During Cardiac Valve Development

Mitral valve prolapse (MVP) affects 2.4% of the population and has poorly understood etiology. Recent genetic studies have begun to unravel the complexities of MVP and through these efforts, mutations in the FLNA (Filamin-A) gene were identified as disease causing. Our in vivo and in vitro studies have validated these genetic findings and have revealed FLNA as a central regulator of valve morphogenesis. The mechanisms by which FLNA mutations result in myxomatous mitral valve disease are currently unknown, but may involve proteins previously associated with mutated regions of the FLNA protein, such as the small GTPase signaling protein, R-Ras. Herein, we report that Filamin-A is required for R-Ras expression and activation of the Ras-Mek-Erk pathway. Loss of the Ras/Erk pathway correlated with hyperactivation of pSmad2/3, increased extracellular matrix (ECM) production and enlarged mitral valves. Analyses of integrin receptors in the mitral valve revealed that Filamin-A was required for β1-integrin expression and provided a potential mechanism for impaired ECM compaction and valve enlargement. Our data support Filamin-A as a protein that regulates the balance between Erk and Smad activation and an inability of Filamin-A deficient valve interstitial cells to effectively remodel the increased ECM production through a β1-integrin mechanism. As a consequence, loss of Filamin-A function results in increased ECM production and generation of a myxomatous phenotype characterized by improperly compacted mitral valve tissue. Anat Rec, 302:117-124, 2019. © 2018 Wiley Periodicals, Inc.