3D Printed Piezoelectric BaTiO3/Polyhydroxybutyrate Nanocomposite Scaffolds for Bone Tissue Engineering

Bone defects are a significant health problem worldwide. Novel treatment approaches in the tissue engineering field rely on the use of biomaterial scaffolds to stimulate and guide the regeneration of damaged tissue that cannot repair or regrow spontaneously. This work aimed at developing and characterizing new piezoelectric scaffolds to provide electric bio-signals naturally present in bone and vascular tissues. Mixing and extrusion were used to obtain nanocomposites made of polyhydroxybutyrate (PHB) as a matrix and barium titanate (BaTiO3) nanoparticles as a filler, at BaTiO3/PHB compositions of 5/95, 10/90, 15/85 and 20/80 (w/w%). The morphological, thermal, mechanical and piezoelectric properties of the nanocomposites were studied. Scanning electron microscopy analysis showed good nanoparticle dispersion within the polymer matrix. Considerable increases in the Young's modulus, compressive strength and the piezoelectric coefficient d31 were observed with increasing BaTiO3 content, with d31 = 37 pm/V in 20/80 (w/w%) BaTiO3/PHB. 3D printing was used to produce porous cubic-shaped scaffolds using a 90° lay-down pattern, with pore size ranging in 0.60-0.77 mm and good mechanical stability. Biodegradation tests conducted for 8 weeks in saline solution at 37 °C showed low mass loss (∼4%) for 3D printed scaffolds. The results obtained in terms of piezoelectric, mechanical and chemical properties of the nanocomposite provide a new promising strategy for vascularized bone tissue engineering.

Coronary plaque characteristics associated with major adverse cardiovascular events in atherosclerotic patients and lesions – a systematic review and meta-analysis

Background

The clinical value of high-risk coronary plaque characteristics (CPCs) to inform intensified medical therapy or revascularization of non-flow-limiting lesion remains uncertain.

Purpose

We performed a systematic review and meta-analysis to study the prognostic impact of CPCs on patient-level and lesion-level major cardiovascular adverse events (MACE).

Methods

We systematically reviewed MEDLINE, EMBASE, and the Cochrane database for studies evaluating the association of CPC with patient-level and lesion-level MACE. CPCs included high plaque burden, low minimal lumen area, thin cap fibroatheroma, high lipid core burden index, low attenuation plaque, spotty calcification, napkin ring sign, or positive remodelling.

Results

Thirty studies (21 retrospective, 9 prospective) with 30,369 patients were included. CPCs were evaluated by invasive intravascular techniques in 9 studies (optical coherence tomography=4, intravascular ultrasound imaging=3, near-infrared spectroscopy intravascular ultrasound imaging=2) and by coronary computed tomography angiography (CCTA) in 21 studies. CPCs significantly predicted patient-level and lesion-level MACE in both unadjusted and adjusted analyses. For each CPC, the risks were higher for lesion-level (HR range 3.2–16.8) as compared with patient-level MACE (HR range 1.8–4.1). Accuracy was modest to good for most CPCs at the patient-level (AUC for MACE ranging between 0.53 and 0.84) and moderate to good for most CPCs at the lesion-level (AUC for MACE ranging between 0.71 and 0.83). Plaques with more than one CPC had the highest accuracy for lesion-level MACE (AUC 0.87, 95% CI 0.84–0.90). The pooled sensitivities of CPCs for lesion-level MACE ranged between 40% and 63% and specificities between 73% and 98%. As the pooled prevalence of CPCs among plaques was low (3% to 28%), the estimated positive predictive values for lesion-level MACE were modest (range 1% to 26%).

Conclusions

CCTA and intravascular imaging characterization of CPCs identifies high-risk atherosclerotic plaques that place lesions and patients at risk for future MACE, albeit with modest sensitivity and positive predictive value (PROSPERO identifier: CRD42021251810).

Funding Acknowledgement

Type of funding sources: None.

Right ventricular longitudinal contractility mismatch: a novel diagnostic marker of right ventricular arrhythmogenic cardiomyopathy

Background

The structural alterations of arrhythmogenic right ventricular (RV) cardiomyopathy (ARVC) mainly involve the RV outflow tract (RVOT), but RVOT systolic function has been poorly investigated.

Purpose

We aimed to evaluate the Doppler Velocity Ratio (DVR) as a novel echocardiographic parameter for ARVC diagnosis.

Methods

30 consecutive ARVC adult patients, 45 asymptomatic healthy volunteers and 45 consecutive patients with RV dysfunction due to ARVC mimics were prospectively enrolled between May 2019 and December 2021 and received complete transthoracic echocardiography examinations. The DVR was calculated as the ratio of RV free wall systolic velocity to RVOT systolic velocity at Doppler tissue imaging. The main study outcomes were to compare the DVR among ARVC patients, healthy controls, and mimics and to assess its diagnostic value in ARVC.

Results

120 patients were included. Mean age was 55±17 years; 46 (38.3%) patients were female. The DVR was significantly higher in ARVC subjects (1.59±0.41) compared to both healthy controls (1.16±0.14, P<0.001) and mimics (1.17±0.23, P<0.001), but similar between healthy controls and mimics (P=1.000). The DVR cut-off value with the highest accuracy for ARVC diagnosis was 1.33 (sensitivity=80.0%, specificity=86.7%). The area under the curve of DVR alone was significantly superior to that of the major echocardiographic 2010 Task Force Criteria (0.833 vs 0.672 respectively, P=0.034). The net reclassification improvement for DVR alone against the major echocardiographic 2010 Task Force Criteria was 32.2% (P=0.023).

Conclusions

The DVR is a simple novel echocardiographic parameter with high accuracy for ARVC diagnosis.

Funding Acknowledgement

Type of funding sources: None.

Right ventricular myocardial work in patients undergoing left ventricular assist device implant

Background

Right ventricular failure (RVF) complicates 10 to 40% of left ventricular assist device (LVAD) implants, with necessity of high dose inotropic/vasodilatory drugs and right ventricular assist devices in severe cases. Prevention of RVF starts with appropriate patient selection for LVAD implant through extensive clinical, echocardiographic and hemodynamic evaluation.

Purpose

This study aimed to evaluate the performance of a novel non-invasive echocardiographic method for estimation of right ventricular myocardial work to predict RVF and death after LVAD implant.

Methods

Consecutive patients from May 2017 to February 2022 undergoing LVAD implant were retrospectively reviewed. Patients without a useful echocardiographic exam and/or a right heart catheterization prior to LVAD implant were excluded. Myocardial work analysis by Speckle Tracking Echocardiography (STE) was performed in these patients. The primary endpoints were RVF and death.

Results

The study included 23 patients (mean age 64±8 years, 91% men). Median follow-up time was 304 days (IQR: 23–1017). GWI significantly correlated with invasively-derived right ventricular stroke work index (RVSWI, r=0.538; p=0.008) and pulmonary arterial compliance (PAC, r=−0.522; p=0.013). Patients who experienced RVF (26.1%) had lower GWI (p=0.047) and GWE (p=0.001) and higher GWW (p=0.001). Patients who experienced death at 30 days after LVAD implant (26.1%) had lower GWE (p=0.005) and higher GWW (p=0.006). Performance for prediction of RVF after LVAD implant was greatest for GWE (AUC 0.92), followed by GWW (AUC 0.88) and GWI (AUC 0.78). A cut-off of 77% for GWE have a 100% sensibility and 82% specificity for prediction of RVF. At long term follow-up, death occurred in 4 patients (29%) in the GWE>77% group and in 6 patients (67%) in the GWE<77% group (hazard ratio for death, 0.24; 95% CI, 0.07 to 0.89, p=0.032).

Conclusions

Right ventricular myocardial work is a strong predictor of RVF after LVAD implant and death at long-term follow up. Its calculation should be implemented in the evaluation for LVAD candidacy.

Funding Acknowledgement

Type of funding sources: None.

Prognostic impact of suboptimal adherence to statin therapy after STEMI: results from the FAST-STEMI registry

Introduction

Patterns and prognostic impact of suboptimal adherence to statin therapy, after STEMI, remains understudied

Purpose

To identify predictors and to estimate the prognostic impact of low statin adherence after STEMI

Method

We evaluated real-world purchase of statins and typical cardiovascular drugs, after STEMI, in a large regional database that enrolled patients from 2012 to 2017; adherence was defined as the ratio of bought tablets divided by the number of expected tablets in the follow-up period. Cox regression was used for multivariate analysis; Kaplan Meier and Cox proportional hazard models were performed to evaluate cumulative event rates of all-cause mortality at follow-up

Results

A total of 4062 patients were enrolled, of which 12.6% died after a median of 4.7 years of follow up (IQR 3.7–5.7). Statin adherence lower than 80%, identified as the best cutoff at Youden's analysis, was identified in 42% of the registry population; statin adherent patients were more likely younger, with known dyslipidemia at enrollment, discharged with ACE inhibitors and a potent P2Y12 inhibitor (ticagrelor or prasugrel), and with a statin diverse from atorvastatin. After multivariate adjustment for in-study outcome predictors, low statin adherence was independently associated with all cause mortality (HR 0.57; 95% CI 0.46–0.70; p<0.001), along with older age, not known dyslipidemia at enrollment and clopidogrel at discharge after STEMI

Conclusions

In the contemporary real-world setting, statin adherence following STEMI remains poor, especially in high risk patients, and is still a crucial independent predictor of all-cause mortality. Effective strategies to improve statint adherence remain an unmet clinical need.

Funding Acknowledgement

Type of funding sources: None.

P388 CORONARY PLAQUE CHARACTERISTICS ASSOCIATED WITH MAJOR ADVERSE CARDIOVASCULAR EVENTS AMONG ATHEROSCLEROTIC PATIENTS AND LESIONS: A SYSTEMATIC REVIEW AND META–ANALYSIS

Background

The clinical value of coronary plaque characteristics (CPCs) to inform intensified medical therapy or revascularization of non–flow–limiting lesion remains uncertain. We performed a systematic review and meta–analysis to study the prognostic impact of CPCs comprehensively assessed with invasive and non–invasive imaging technologies on patient–level and lesion–level major cardiovascular adverse events (MACE).

Methods

We systematically reviewed MEDLINE, EMBASE, and the Cochrane database for studies evaluating the association of CPC with patient–level and lesion–level (MACE). CPCs included high plaque burden, low minimal lumen area, thin cap fibroatheroma, high lipid core burden index, low attenuation plaque, spotty calcification, napkin ring sign or positive remodelling.

Results

Thirty studies (21 retrospective, 9 prospective) with 30.369 patients were included. CPCs were evaluated by invasive intravascular techniques in 9 studies (optical coherence tomography=4, intravascular ultrasound imaging=3, near–infrared spectroscopy intravascular ultrasound imaging=2) and by coronary computed tomography angiography (CCTA) in 21 studies. CPCs were significantly predictive of patient–level and lesion–level MACE, also when only adjusted data where considered. For each CPC, the odds appeared higher for lesion–level (HR range 3.2–16.8) as compared to patient–level MACE (HR range 1.8–4.1). Accuracy was modest to moderate for most CPCs at the patient–level (AUC for MACE ranging between 0.53 and 0.84) and moderate to good for most CPCs at the lesion–level (AUC for MACE ranging between 0.71 and 0.83). Plaques with more than one CPC had the highest accuracy for lesion–level MACE (AUC 0.87, 95%CI 0.84–0.90). CPC pooled sensitivities for lesion–level MACE ranged between 40% and 63% and specificities between 73% and 98%. As the pooled prevalence of CPCs among plaques was low (3% to 28%), the estimated positive predictive values for lesion–level MACE were modest (range 33% to 45%).

Conclusion

CCTA and intravascular imaging characterization of CPCs provides independent prognostic value among atherosclerotic patients and lesions. However, the modest sensitivity and positive predictive value observed across all CPCs seem to suggest modest clinical value, especially to predict lesion–level events (PROSPERO identifier: CRD42021251810).

P102 NEW THREE–DIMENSIONAL ECHOCARDIOGRAPHIC PREDICTING PARAMETERS IN TRANS–VENTRICULAR HEART–BEATING MITRAL VALVE REPAIR WITH NEOCHORDAE: A MONOCENTRIC RETROSPECTIVE STUDY

Background

Trans–ventricular off pump mitral valve (MV) repair with neochordae implantation (Neochord procedure) is a minimally invasive surgical technique for correction of degenerative mitral regurgitation (MR) due to prolapse or flail. The aim of this study was to evaluate mid–term results of patients undergoing this procedure and find new three–dimensional pre–operative echocardiographic parameters to predict MR recurrence at follow–up.

Methods

We performed a retrospective analysis of 72 consecutive patients with severe MR due to prolapse or flail who underwent Neochord procedure at our hospital from March 2015 to February 2021. MV pre–operative anatomical parameters were assessed using 2D TEE, 3D TEE and dedicated three–dimensional (3D) post–processing analysis with dedicated software (QLAB, Philips). TTE follow–up and clinical evaluation were performed at 3 months, 6 months, 1 year and then annually.

Results

Twenty–seven patients were female (37.5%), mean age was 77±9 years. The average preoperative EuroSCORE II was 2.2%±1.5%. Twenty–three patients (32%) had an history of paroxysmal or persistent atrial fibrillation. Procedural success at discharge was achieved in sixty–eight patients (94.5%). Mean follow–up was 30±16 months. Three years follow–up was completed by fifty patients. At three years thirteen patients (26%) presented with recurrence of severe MR or underwent new surgical operation. Prevalence of mild or trace MR at three years follow–up visit was 70%. End–systolic annulus area (12.5±2.5 cm2 vs 14.1±2.6 cm2; p = 0.038), end–systolic annulus diameter (13.2±1.2 cm vs 14±1.3 cm; p = 0.042) and indexed left atrial volume (59±17 ml/m2 vs 76±37 ml/m2; p = 0.041) were lower in patients with residual MR less than moderate (MR < 3+/4+). Three–dimensional indexes specifically focused on coaptation reserve and annular disfunction were the best predictors of MR < 3+/4+ at follow–up, in particular diastolic sum of the leaflets/end–systolic annulus area ([AUC] 0.74; p = 0.029) and systo–diastolic annulus area fractional change ([AUC] 0.743; p = 0.035). Furthermore, each of these annular parameters, calculated using dedicated 3D software, were predictive of residual MR, whereas annular 2D dimensions were not (p = 0.347).

Conclusion

In patients with degenerative MR treated with Neochord procedure, 3D analysis focused on annular measures and coaptation indexes, that included 3D annular dimensions, predicts better MR relapse than conventional 2D parameters.

C25 PREDICTION OF ALL–CAUSE MORTALITY FOLLOWING PERCUTANEOUS CORONARY INTERVENTION IN BIFURCATION LESIONS USING MACHINE LEARNING ALGORITHMS – THE RAIN–ML PREDICTION MODEL

Aims

Stratifying prognosis following coronary bifurcation percutaneous coronary intervention (PCI) is an unmet need. Machine learning (ML) may identify patterns from multidimensional, non–linear relationships to make outcome predictions. We sought to develop a ML–based risk stratification model built on clinical, anatomical and procedural features to predict all–cause mortality following contemporary bifurcation PCI.

Methods and Results

Multiple ML models to predict all–cause mortality were tested on a cohort of 2,393 patients (training, n = 1,795; internal validation, n = 598) undergoing bifurcation PCI with contemporary stents from the real–world RAIN (veRy thin stents for patients with left mAIn or bifurcatioN in real life) registry. Among 38 commonly available features, 25 (13 patient–related, 12 lesion–related) were selected to train ML models. The best performing model (the RAIN–ML prediction model) was validated in an external validation cohort of 1,701 patients undergoing bifurcation PCI from the DUTCH PEERS (DUrable polymer–based sTent CHallenge of Promus ElemEnt versus ReSolute integrity: TWENTE II) trial and the BIO–RESORT trial cohorts. The area under the receiver operating characteristic curves for the prediction of 2–year mortality was 0.786 (0.74–0.83) in the overall population, 0.736 (0.72–0.847) at internal validation and 0.706 (0.6919–0.794) at external validation. Performance at risk ranking analysis, k–center cross validation, and with continual learning confirmed the generalizability of the models, available also as an online interface.

Conclusions

The RAIN–ML prediction model represents the first tool combining clinical, anatomical and procedural features to predict all–cause mortality among patients undergoing contemporary bifurcation PCI with a good discriminative performance.

P316 TRANSTHYRETIN CARDIAC AMYLOIDOSIS IN PATIENTS WITH SEVERE AORTIC STENOSIS UNDERGOING TRANSCATHETER AORTIC VALVE REPLACEMENT: A SINGLE CENTER EXPERIENCE

Background

Even if prevalent among patients with severe aortic stenosis (AS), the clinical suspicion for transthyretin cardiac amyloidosis (ATTR–CA) remains difficult in this subset.

Methods

Consecutive severe AS patients undergoing transcatheter aortic valve replacement (TAVR) evaluation at a single center were prospectively included. Those with suspected ATTR–CA based on clinical assessment underwent 99mTc–DPD cardiac scintigraphy. The RAISE score, a novel screening tool with high sensitivity for ATTR–CA in AS, was retrospectively calculated to rule–out ATTR–CA in the remaining patients. Patients were categorized as follow: “ATTR–CA +”: patients with confirmed ATTR–CA at 99mTc–DPD cardiac scintigraphy; “ATTR–CA –”: patients with negative 99mTc–DPD cardiac scintigraphy or a negative RAISE score; c) “ATTR–CA indeterminate”: patients not undergoing ATTR–CA assessment with a positive RAISE score. The characteristics and outcomes of ATTR–CA + and ATTR–CA – patients were compared.

Results

Of 107 included patients, ATTR–CA suspicion was posed in 13 patients and confirmed in 6. Patients were categorized as follow: 6 (5.6%) ATTR–CA +, 79 (73.8%) ATTR–CA –, 22 (20.6%) ATTR–CA indeterminate. Excluding ATTR–CA indeterminate patients, the prevalence of ATTR–CA was 7.1%. As compared to ATTR–CA – patients, ATTR–CA + patients were older, had higher procedural risk and more extensive myocardial and renal damage. They had higher left ventricle mass index and lower ECG voltages, translating into a lower voltage to mass ratio. Moreover, bifascicular block was more common. No difference in procedural outcomes and 1–year mortality was observed between groups.

Conclusions

Among severe AS patients, ATTR–CA is prevalent and presents with phenotypic features that may aid to differentiate it from lone AS. The procedural and mid–term outcomes following TAVR seems unaffected by ATTR–CA status.

Genetic and chemotherapeutic influences on germline hypermutation

Mutations in the germline generates all evolutionary genetic variation and is a cause of genetic disease. Parental age is the primary determinant of the number of new germline mutations in an individual's genome1,2. Here we analysed the genome-wide sequences of 21,879 families with rare genetic diseases and identified 12 individuals with a hypermutated genome with between two and seven times more de novo single-nucleotide variants than expected. In most families (9 out of 12), the excess mutations came from the father. Two families had genetic drivers of germline hypermutation, with fathers carrying damaging genetic variation in DNA-repair genes. For five of the families, paternal exposure to chemotherapeutic agents before conception was probably a key driver of hypermutation. Our results suggest that the germline is well protected from mutagenic effects, hypermutation is rare, the number of excess mutations is relatively modest and most individuals with a hypermutated genome will not have a genetic disease.

TADA-a machine learning tool for functional annotation-based prioritisation of pathogenic CNVs

Few methods have been developed to investigate copy number variants (CNVs) based on their predicted pathogenicity. We introduce TADA, a method to prioritise pathogenic CNVs through assisted manual filtering and automated classification, based on an extensive catalogue of functional annotation supported by rigourous enrichment analysis. We demonstrate that our classifiers are able to accurately predict pathogenic CNVs, outperforming current alternative methods, and produce a well-calibrated pathogenicity score. Our results suggest that functional annotation-based prioritisation of pathogenic CNVs is a promising approach to support clinical diagnostics and to further the understanding of mechanisms controlling the disease impact of larger genomic alterations.

Detecting cryptic clinically relevant structural variation in exome-sequencing data increases diagnostic yield for developmental disorders

Structural variation (SV) describes a broad class of genetic variation greater than 50 bp in size. SVs can cause a wide range of genetic diseases and are prevalent in rare developmental disorders (DDs). Individuals presenting with DDs are often referred for diagnostic testing with chromosomal microarrays (CMAs) to identify large copy-number variants (CNVs) and/or with single-gene, gene-panel, or exome sequencing (ES) to identify single-nucleotide variants, small insertions/deletions, and CNVs. However, individuals with pathogenic SVs undetectable by conventional analysis often remain undiagnosed. Consequently, we have developed the tool InDelible, which interrogates short-read sequencing data for split-read clusters characteristic of SV breakpoints. We applied InDelible to 13,438 probands with severe DDs recruited as part of the Deciphering Developmental Disorders (DDD) study and discovered 63 rare, damaging variants in genes previously associated with DDs missed by standard SNV, indel, or CNV discovery approaches. Clinical review of these 63 variants determined that about half (30/63) were plausibly pathogenic. InDelible was particularly effective at ascertaining variants between 21 and 500 bp in size and increased the total number of potentially pathogenic variants identified by DDD in this size range by 42.9%. Of particular interest were seven confirmed de novo variants in MECP2, which represent 35.0% of all de novo protein-truncating variants in MECP2 among DDD study participants. InDelible provides a framework for the discovery of pathogenic SVs that are most likely missed by standard analytical workflows and has the potential to improve the diagnostic yield of ES across a broad range of genetic diseases.

Valve-in-valve transcatheter aortic valve replacement or re-surgical aortic valve replacement in degenerated bioprostheses: a systematic review and meta-analysis of short and mid-term results

Introduction

Despite limited to short and mid-term outcomes, Valve-in-valve (ViV) transcatheter aortic valve implantation (TAVI) has emerged as a less invasive alternative to redo surgery for high and intermediate-risk patients with good outcomes across different surgical risk profiles.

Purpose

The aim of the resent meta-analysis is to compare short and mid-term outcomes of VIV and surgical redo fo patients with a degenerative aortic bioprosthesis.

Methods

All studies comparing with multivariate adjustment between ViV TAVI and re-SAVR were screened. All-cause mortality at 30-day and at follow-up were the primary endpoints, while Valve Academy research Consortium (VARC) endpoints at 30 days including stroke, myocardial infarction (MI), major vascular complications, major bleeding, new onset atrial fibrillation (AF) and permanent pacemaker implantation (PPI) during the index hospitalization were the secondary endpoints. Subgroup analysis were performed according to the surgical risk. All the analyses were stratified according to the design of the study (observational vs propensity-matched study).

Results

We obtained data from 11 studies, encompassing 8570 patients, 4224 undergoing ViV TAVI and 4346 re-SAVR. Four studies included intermediate-risk patients and seven high-risk patients. Mean age was 76 and 71.5 years in the ViV and re-SAVR group respectively, with a 60.2% and 61.3% of male. For the ViV procedure, BE prostheses were used in the 49.6% of patients and SE prostheses in the 45.8%. The ViV group have higher prevalence of previous CAD (53.8% vs 41.1%) and CABG (35% vs 23.6%) and more history of HF (72.1% vs 65.6%), CKD (26.6% vs 14.8%) and COPD (25.4 vs 14.8%). 30-day all-cause and CV mortality were significantly lower in ViV (OR 0.43, 0.29–0.64 and OR 0.44, 0.26–0.73 respectively), while after a mean follow-up of 717 (180–1825) days, there were no difference between the two groups (OR 1.04, 0.87–1.25 and OR 1.05, 0.78–1.43 respectively). The result were consistent both in intermediate and high-risk classes. The risk of stroke (OR 1.03, 0.59–1.82), MI (OR 0.70, 0.34–1.44), major vascular complications (OR 0.92, 0.50–1.67) and permanent pacemaker implantation (OR 0.67, 0.36–1.25) at 30 days did not differ, while major bleedings and new onset atrial fibrillation were significantly lower in ViV patients (OR 0.41, 0.25–0.67 and OR 0.23, 0.12–0.42 respectively, all CI 95%).

Conclusions

In patients with a degenerated aortic bioprosthesis, ViV TAVI is associated with better short-term outcomes, including all-cause mortality, without any difference in all-cause and cardiovascular mortality at mid-term follow-up compared to surgical redo.

Funding Acknowledgement

Type of funding sources: None.

Non-coding region variants upstream of MEF2C cause severe developmental disorder through three distinct loss-of-function mechanisms

Clinical genetic testing of protein-coding regions identifies a likely causative variant in only around half of developmental disorder (DD) cases. The contribution of regulatory variation in non-coding regions to rare disease, including DD, remains very poorly understood. We screened 9,858 probands from the Deciphering Developmental Disorders (DDD) study for de novo mutations in the 5' untranslated regions (5' UTRs) of genes within which variants have previously been shown to cause DD through a dominant haploinsufficient mechanism. We identified four single-nucleotide variants and two copy-number variants upstream of MEF2C in a total of ten individual probands. We developed multiple bespoke and orthogonal experimental approaches to demonstrate that these variants cause DD through three distinct loss-of-function mechanisms, disrupting transcription, translation, and/or protein function. These non-coding region variants represent 23% of likely diagnoses identified in MEF2C in the DDD cohort, but these would all be missed in standard clinical genetics approaches. Nonetheless, these variants are readily detectable in exome sequence data, with 30.7% of 5' UTR bases across all genes well covered in the DDD dataset. Our analyses show that non-coding variants upstream of genes within which coding variants are known to cause DD are an important cause of severe disease and demonstrate that analyzing 5' UTRs can increase diagnostic yield. We also show how non-coding variants can help inform both the disease-causing mechanism underlying protein-coding variants and dosage tolerance of the gene.

The contribution of X-linked coding variation to severe developmental disorders

Over 130 X-linked genes have been robustly associated with developmental disorders, and X-linked causes have been hypothesised to underlie the higher developmental disorder rates in males. Here, we evaluate the burden of X-linked coding variation in 11,044 developmental disorder patients, and find a similar rate of X-linked causes in males and females (6.0% and 6.9%, respectively), indicating that such variants do not account for the 1.4-fold male bias. We develop an improved strategy to detect X-linked developmental disorders and identify 23 significant genes, all of which were previously known, consistent with our inference that the vast majority of the X-linked burden is in known developmental disorder-associated genes. Importantly, we estimate that, in male probands, only 13% of inherited rare missense variants in known developmental disorder-associated genes are likely to be pathogenic. Our results demonstrate that statistical analysis of large datasets can refine our understanding of modes of inheritance for individual X-linked disorders.

Targeted RNA sequencing enhances gene expression profiling of ultra-low input samples

RNA-seq is the standard method for profiling gene expression in many biological systems. Due to the wide dynamic range and complex nature of the transcriptome, RNA-seq provides an incomplete characterization, especially of lowly expressed genes and transcripts. Targeted RNA sequencing (RNA CaptureSeq) focuses sequencing on genes of interest, providing exquisite sensitivity for transcript detection and quantification. However, uses of CaptureSeq have focused on bulk samples and its performance on very small populations of cells is unknown. Here we show CaptureSeq greatly enhances transcriptomic profiling of target genes in ultra-low-input samples and provides equivalent performance to that on bulk samples. We validate the performance of CaptureSeq using multiple probe sets on samples of iPSC-derived cortical neurons. We demonstrate up to 275-fold enrichment for target genes, the detection of 10% additional genes and a greater than 5-fold increase in identified gene isoforms. Analysis of spike-in controls demonstrated CaptureSeq improved both detection sensitivity and expression quantification. Comparison to the CORTECON database of cerebral cortex development revealed CaptureSeq enhanced the identification of sample differentiation stage. CaptureSeq provides sensitive, reliable and quantitative expression measurements on hundreds-to-thousands of target genes from ultra-low-input samples and has the potential to greatly enhance transcriptomic profiling when samples are limiting.

Fractional flow reserve (FFR) guided vs angiography guided coronary artery bypass graft (CABG): a systematic review and meta-analysis

Background

A strategy of percutaneous coronary intervention (PCI) driven by FFR (Fractional Flow Reserve) has demonstrated to reduce adverse events through the “deferring” of unnecessary stenting procedures compared to PCI guided by angiographic evaluation of stenosis. Coronary Artery Bypass Graft (CABG) represents another option for revascularization, being superior to PCI in patients with diffuse disease. In this setting, some evidence has been provided about physiological driven CABG procedures, but studies reported contrasting results regarding clinical benefits and outcomes at follow up.

The aim of this meta-analysis is to evaluate clinical and procedural impact of FFR versus angiographic guided surgical revascularization and assess outcomes at follow up.

Methods

All randomized controlled trials (RCTs) or observational studies with multivariable adjustment or propensity matching were included. MACE (Major Adverse Cardiac Events) was the primary end point, while its single components (death, myocardial infarction and revascularization) along with number of grafts and percent of off-pump CABG were the secondary ones. Of 86 studies identified, 4 articles were included in this review, representing a combined total of 777 patients (426 angio-guided and 351 FFR-guided). Mean age was 66±2.1, 80% man, 74% hypertension, 71% hyperlipidemia, 33% diabetes, 39% smokers. Mean EuroSCORE I was 2.7. 18% a prior MI, and 25% a prior PCI. Coronary lesions were allocated as follow: 36% left anterior descending artery, 32% circumflex artery, 27% right coronary artery. Mean follow up was 30 months. At the follow up, rates of MACE did not differ (MACE OR 1.31:0.88–1.96), as those of death (OR 1.47:0.86–2.51), of MI (OR 1.80:0.89–3.63), and of target vessel revascularization (1.03: 0.54–1.97.). FFR-guided CABG was associated with more off-pump surgical procedure (OR 0.58, IC 0.34–0.97) and shorter hospitalization time (8.2±2.49 vs 8,87±3,25 p<0.01). FFR- guided CABG was associated more frequently with off-pump surgical procedure (OR 0.58:0.34–0.97) with fewer anastomes (2.5 vs 3), leading to higher rates of global arteria revascularization in FFR group (56% vs. 45%) and higher rates of venous grafts in angio-guided group (55% vs. 44%). Shorter hospitalization time was recorded in FFR patients (8.2±2.49 vs 8,87±3,25 days, p<0.01). Graft patency at follow up was not statistically higher in the FFR guided group (OR 0.67, CI 95% 0.32–1,39, all CI 95%).

Conclusions

FFR-guided surgical revascularization is associated with more off-pump procedures, a lower number of surgical anastomoses and more arterial grafts compared to angiography guided CABG. These differences lead to a shorter hospitalization time in the FFR-guided group compared to the angiography-guided group. No difference between two groups in MACE, overall death and MI was observed during the follow up. RCT with longer follow up are needed to evaluate long term outcomes.

Funding Acknowledgement

Type of funding source: None

Intelligent non-colorimetric indicators for the perishable supply chain by non-wovens with photo-programmed thermal response

Spoiled perishable products, such as food and drugs exposed to inappropriate temperature, cause million illnesses every year. Risks range from intoxication due to pathogen-contaminated edibles, to suboptimal potency of temperature-sensitive vaccines. High-performance and low-cost indicators are needed, based on conformable materials whose properties change continuously and irreversibly depending on the experienced time-temperature profile. However, these systems can be limited by unclear reading, especially for colour-blind people, and are often difficult to be encoded with a tailored response to detect excess temperature over varying temporal profiles. Here we report on optically-programmed, non-colorimetric indicators based on nano-textured non-wovens encoded by their cross-linking degree. This combination allows a desired time-temperature response to be achieved, to address different perishable products. The devices operate by visual contrast with ambient light, which is explained by backscattering calculations for the complex fibrous material. Optical nanomaterials with photo-encoded thermal properties might establish new design rules for intelligent labels.

Predictors of fractional flow reserve/instantaneous wave-free ratio discordance documented during functional coronary stenosis assessment: impact of tailored diagnostic cut-offs on long-term outcomes

Background

Patient- and lesion-related factors may influence concordance between instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR), potentially affecting safety of revascularization deferral.

Methods

Consecutive patients with at least an intermediate coronary stenosis evaluated by both iFR and FFR were retrospectively enrolled. Revascularization was at physician's discretion. The agreement between IFR and FFR at their diagnostic cut-offs (FFR 0.80, iFR 0.89) according to patient- and lesion-level characteristics was assessed. Multivariate analyses were carried to identify the independent predictors of discordance. Tailored iFR cut-offs according to predictors of discordance best matching an FFR of 0.80 were identified by receiver-operating characteristic (ROC) curves. The impact of reclassification according to tailored iFR cut-offs on major cardiovascular events (MACE: cardiovascular death, myocardial infarction or target lesion revascularization) among deferred lesions was investigated.

Results

299 coronary stenosis (diameter stenosis 54±14%, FFR 0.84 [0.78–0.89], iFR 0.91 [0.87–0.95], left main/left anterior descending [LM/LAD] vessel 67.6%) of 260 patients were studied, and 46.5% were revascularized. Discordance rate was 23.4% (10.7% iFR-negative discordant, 12.7% iFR-positive discordant). Independent predictors of discordance were LM/LAD disease, multivessel disease, non-ST-elevation myocardial infarction presentation, smoking, reduced glomerular filtration rate and hypertension. Lesion reclassification with tailored iFR-cut-offs based on patient-level predictors carried no prognostic value among deferred lesions. Reclassification according to lesion location, which was entirely driven by LM/LAD lesions (iFR-cut-offs: 0.93 for LM/LAD, 0.89 for non-LM/LAD), identified increased MACE among lesions deferred based on a negative FFR, between patients with a positive as compared to a negative iFR (19.4% vs. 6.1%, p=0.044), while the same association was not observed with the conventional 0.89 iFR cut-off (15.0% vs 8.6%, p=0.303).

Conclusion

Tailored vessel-based iFR cut-offs carry prognostic value among FFR negative lesions, suggesting that iFR may more safely defer revascularization of LM/LAD lesions than FFR and that a single iFR cut-off might be clinically unsatisfactory.

Funding Acknowledgement

Type of funding source: None

Prognostic value and usefulness of Pulmonary Artery Pulsatility index (PAPi) in evaluation of heart transplant candidates

Background

Heart transplantation (HTx) is considered the best available treatment for patients with end stage heart failure. Candidate evaluation with right heart catheterization (RHC) is fundamental in order to exclude pulmonary hypertension with irreversible high pulmonary vascular resistance (PVR), which is associated with elevated post-HTx mortality. PVR, rather than directly measured, is derived by cardiac output and pulmonary artery pressures, which are strictly dependent on right ventricular (RV) function. The pulmonary artery pulsatility index (PAPi) is a hemodynamic parameter integrating the information of RV function and of pulmonary circulation, which could be useful in pre-HTx evaluation.

Purpose

We designed this study to evaluate the potential predictive influence of pre-HTx PAPi on post-HTx survival and to assess whether this index could add useful information in the pre-HTx evaluation of patients with advanced heart failure.

Methods

Consecutive adult HTx recipient at two medium-large tranplant centers between 2000 and 2017 with available data on pre-HTx RHC were retrospectively included. PAPi was calculated as the ratio of pulmonary artery pulse pressure to right atrial pressure. PAPi values in the lowest quartile were defined as reduced (PAPi<1.67). The primary endpoint was all-cause mortality at 1-year post-HTx. The association of reduced PAPi with the primary endpoint was evaluated. Cox regression was used to adjust for clinical and hemodynamic variables. Analyses stratified by PVR status (≥3 WU vs. <3 WU) were also performed.

Results

Among 655 HTx recipients (female 20,8%, age 53±11 years), median pre-HTx PAPi was 3.0 (interquartile range 1.67–5.32). Patients in the lowest versus the remaining PAPi quartiles had significantly reduced 1-year survival (78.0% vs 87.2%, p=0.006), also after adjusting for age, estimated glomerular filtration rate, total bilirubin, high PVR and urgent transplantation (adj-hazard ratio: 0.64; 95% confidence interval 0.51–0.82). When stratifying patients by estimated PVR status, reduced PAPi was associated with worse 1-year survival among patients with normal PVR (78.3% vs. 88.3% p=0.011), but not in those with increased PVR (78.0% vs. 82.6%, p=0.36) (Figure 1).

Conclusions

Pre-HTx PAPi, integrating information of RV function and pulmonary circulation, provides incremental prognostic value over traditional clinical and hemodynamic parameters among HTx recipient. The prognostic value appears important among patients with normal estimated PVR, possibly due to an underestimation of PVR in patients with impaired RV function. The integration of PAPi in the pre-HTx evaluation may lead to better patient selection and post-HTx survival.

Figure 1. 1 year survival stratified by PVR status

Funding Acknowledgement

Type of funding source: None

Use of extracorporeal membrane oxygenation in acute pulmonary embolism: a pooled analysis

Background

High-risk acute pulmonary embolism (PE) is burdened by a mortality as high as 65%. VenoArterial ExtraCorporeal Membrane Oxygenation (VA-ECMO) may offer a cardiopulmonary support and a precious time window to ensure pulmonary reperfusion therapies. No definite consensus exists on the use of VA-ECMO in high-risk PE patients as only sparse observational studies are available yielding conflicting outcomes.

Purpose

To provide insights on the use of ECMO in acute high-risk PE pooling together all available published experiences to date.

Methods

Two authors (LB, AB) searched PubMed, Embase, BioMedCentral and Google Scholar, from inception to 18/09/2019. All published clinical studies investigating ECMO support in patients with high-risk acute PE were evaluated for inclusion.

Results

Literature search identified 384 observational studies: a total of 66 were included for 584 acute high-risk PE patients receiving ECMO support. Mean age was 46.8±16.8 years (44% female). Most patients presented with cardiac arrest (56%) or obstructive shock (42%). Diagnosis of PE was confirmed by computed tomography (CT) in 72%, performed before ECMO cannulation in 65%. Echocardiography was obtained in 89%. Right ventricle dilatation or dysfunction was found in 90% and 87%. ECMO was primarily employed as upfront treatment (63%), in the VA-ECMO configuration (94%). ECMO was equally employed in conjunction with interventional/surgical pulmonary reperfusion treatments (38%), with thrombolysis (35%) and without adjunctive procedures (40%). Mean ECMO support duration was 100.3±12.9 hours. Notably, 92% received thrombolysis before ECMO cannulation. ECMO bailout implant was mostly adopted in patients receiving thrombolysis (81% vs 19%; p=0.010), as a rescue therapy. Most common reperfusion procedures were surgical embolectomy (28%), catheter-directed thrombolysis (12%) and transcatheter embolectomy (12%). The majority of these procedures (81%) took place after ECMO cannulation. Mean total hospital stay was 17.8±11.6 days. Hospital survival rate was 54% and did not differ in upfront vs bailout ECMO (p=0.184) and between thrombolysis, interventional procedure and ECMO alone recipients (p=0.423). Neurologic death and non-fatal neurologic injury occurred both in 10%. Most patients (70%) were successfully weaned off ECMO, while 30% died on support and 7% died after ECMO removal. Acute kidney injury was the most common complication (47%). Major bleeding occurred in 19% and was fatal for 5%. Patients undergoing thrombolysis had a tendency towards higher rates of major bleeding (48% vs 23%; p=0.05). At a mean follow-up of 365.0 (IQR 202.5–365.9) days, overall survival rate was 85% in those surviving hospitalization.

Conclusions

In this pooled population consisting mostly of cardiac arrest/obstructive shock PE patients, ECMO strategy was associated with acceptable in-hospital survival and was frequently used in conjunction with other reperfusion treatments.

Central Illustration

Funding Acknowledgement

Type of funding source: None

Evidence for 28 genetic disorders discovered by combining healthcare and research data

De novo mutations in protein-coding genes are a well-established cause of developmental disorders1. However, genes known to be associated with developmental disorders account for only a minority of the observed excess of such de novo mutations1,2. Here, to identify previously undescribed genes associated with developmental disorders, we integrate healthcare and research exome-sequence data from 31,058 parent-offspring trios of individuals with developmental disorders, and develop a simulation-based statistical test to identify gene-specific enrichment of de novo mutations. We identified 285 genes that were significantly associated with developmental disorders, including 28 that had not previously been robustly associated with developmental disorders. Although we detected more genes associated with developmental disorders, much of the excess of de novo mutations in protein-coding genes remains unaccounted for. Modelling suggests that more than 1,000 genes associated with developmental disorders have not yet been described, many of which are likely to be less penetrant than the currently known genes. Research access to clinical diagnostic datasets will be critical for completing the map of genes associated with developmental disorders.

Biodegradable Polymeric Micro/Nano-Structures with Intrinsic Antifouling/Antimicrobial Properties: Relevance in Damaged Skin and Other Biomedical Applications

Bacterial colonization of implanted biomedical devices is the main cause of healthcare-associated infections, estimated to be 8.8 million per year in Europe. Many infections originate from damaged skin, which lets microorganisms exploit injuries and surgical accesses as passageways to reach the implant site and inner organs. Therefore, an effective treatment of skin damage is highly desirable for the success of many biomaterial-related surgical procedures. Due to gained resistance to antibiotics, new antibacterial treatments are becoming vital to control nosocomial infections arising as surgical and post-surgical complications. Surface coatings can avoid biofouling and bacterial colonization thanks to biomaterial inherent properties (e.g., super hydrophobicity), specifically without using drugs, which may cause bacterial resistance. The focus of this review is to highlight the emerging role of degradable polymeric micro- and nano-structures that show intrinsic antifouling and antimicrobial properties, with a special outlook towards biomedical applications dealing with skin and skin damage. The intrinsic properties owned by the biomaterials encompass three main categories: (1) physical–mechanical, (2) chemical, and (3) electrostatic. Clinical relevance in ear prostheses and breast implants is reported. Collecting and discussing the updated outcomes in this field would help the development of better performing biomaterial-based antimicrobial strategies, which are useful to prevent infections.

Optical Interrogation of Sympathetic Neuronal Effects on Macroscopic Cardiomyocyte Network Dynamics

Cardiac stimulation via sympathetic neurons can potentially trigger arrhythmias. We present approaches to study neuron-cardiomyocyte interactions involving optogenetic selective probing and all-optical electrophysiology to measure activity in an automated fashion. Here we demonstrate the utility of optical interrogation of sympathetic neurons and their effects on macroscopic cardiomyocyte network dynamics to address research targets such as the effects of adrenergic stimulation via the release of neurotransmitters, the effect of neuronal numbers on cardiac behavior, and the applicability of optogenetics in mechanistic in vitro studies. As arrhythmias are emergent behaviors that involve the coordinated activity of millions of cells, we image at macroscopic scales to capture complex dynamics. We show that neurons can both decrease and increase wave stability and re-entrant activity in culture depending on their induced activity-a finding that may help us understand the often conflicting results seen in experimental and clinical studies.

Ranbow: A fast and accurate method for polyploid haplotype reconstruction

Reconstructing haplotypes from sequencing data is one of the major challenges in genetics. Haplotypes play a crucial role in many analyses, including genome-wide association studies and population genetics. Haplotype reconstruction becomes more difficult for higher numbers of homologous chromosomes, as it is often the case for polyploid plants. This complexity is compounded further by higher heterozygosity, which denotes the frequent presence of variants between haplotypes. We have designed Ranbow, a new tool for haplotype reconstruction of polyploid genome from short read sequencing data. Ranbow integrates all types of small variants in bi- and multi-allelic sites to reconstruct haplotypes. To evaluate Ranbow and currently available competing methods on real data, we have created and released a real gold standard dataset from sweet potato sequencing data. Our evaluations on real and simulated data clearly show Ranbow’s superior performance in terms of accuracy, haplotype length, memory usage, and running time. Specifically, Ranbow is one order of magnitude faster than the next best method. The efficiency and accuracy of Ranbow makes whole genome haplotype reconstruction of complex genome with higher ploidy feasible.

We focus on the problem of reconstructing haplotypes for polyploid genomes. Our approach explored using short read sequence data from a highly heterozygous hexaploid genome. We observed that short read data from strongly heterozygous organisms open up a way for haplotype reconstruction by supplying overlap information between reads. We therefore investigated the role of heterozygosity and ploidy number. Though higher heterozygosity provides more useful reads for reconstructing haplotypes, polyploidy increases the challenge in assembling reads into longer sequences. We called this the problem of “Ambiguity of Merging” fragments. We addressed this problem by designing a new algorithm called Ranbow. Ranbow was evaluated on real and simulated data from the genomes of tetraploid Capsella bursa-pastoris (Shepherd’s Purse) and hexaploid Ipomoea batatas (sweet potato). We were able to show that our method achieved high accuracy and long assembled haplotypes in a feasible amount of time, performing at a level consistently superior to other algorithms.

Electric field induced alignment of graphene oxide nanoplatelets in polyethersulfone matrix

In recent years, in order to obtain improved mechanical, thermal, electrical and barrier/transport properties, aligned carbonaceous nanomaterials/polymer nanocomposite films have been receiving growing attention. Correspondingly, the edge oxidized graphene oxide (EOGO) nanoplatelets alignment influence on the structure of the polyethersulfone (PES) membrane films for potential applications in water treatment field has been investigated. Aligned GO/PES nanocomposite membrane films were prepared by non-solvent phase inversion technique after the starting sol phase was preliminarily exposed to high electric fields (50 kV m^-1). Either AC (100, 1000 Hz) or DC mode electric fields were alternatively employed, and the results from both vertical and horizontal field configurations were investigated for structural and morphological comparison. Both XRD, FTIR-ATR, EIS, SEM, TEM and tensile strength analyses were applied in order to characterize the films. The microscopic analyses results have demonstrated successful GO/PES nanocomposite formation and alignment of GO nanoplatelets with the field direction in the matrix at low to moderate (0.02-0.1% wt) GO loadings where the flakes were dispersed and exfoliated sufficiently. However, at higher loading levels (1 and 2% wt) the nanoplateles were mostly agglomerated and the big flakes consisting of irregular plates could not orient their axis parallel to the electric field at the employed field strengths. The results suggest a more effective role of higher frequencies (1000 Hz versus 100 Hz) electric field for alignment of GO nanoplatelets. Simple tensile tests have also similarly confirmed GO alignment under the electric fields at both low (0.1% wt) and moderately high (0.5% wt) GO contents. The tensile strength improvement of the horizontal field processed PES/GO nanocomposite up to 24% compared to its vertical field processed counterpart could be accounted as a proof of the successful alignment of the nanoplatelets. However, EIS results unveiled that non-solvent phase inversion casting method, in its general form, may not be a suitable method for producing materials with tailored properties, due to its random and uncontrollable pore forming mechanism.

Contribution of retrotransposition to developmental disorders

Mobile genetic Elements (MEs) are segments of DNA which can copy themselves and other transcribed sequences through the process of retrotransposition (RT). In humans several disorders have been attributed to RT, but the role of RT in severe developmental disorders (DD) has not yet been explored. Here we identify RT-derived events in 9738 exome sequenced trios with DD-affected probands. We ascertain 9 de novo MEs, 4 of which are likely causative of the patient's symptoms (0.04%), as well as 2 de novo gene retroduplications. Beyond identifying likely diagnostic RT events, we estimate genome-wide germline ME mutation rate and selective constraint and demonstrate that coding RT events have signatures of purifying selection equivalent to those of truncating mutations. Overall, our analysis represents a comprehensive interrogation of the impact of retrotransposition on protein coding genes and a framework for future evolutionary and disease studies.

P2794Real-world reasons and outcomes for 1-month versus longer dual antiplatelet therapy strategies with a polymer-free biolimus A9-coated stent: insights from the all-comers FREEDOM registry

Background

The LEADERS FREE trial established the favourable clinical profile of a new polymer-free biolimus A9-eluting stent (PF-BES) in patients at high bleeding risk when used with a 1-month dual anti-platelet therapy (DAPT) strategy.

Purpose

This is the first study evaluating real-world reasons and outcomes for a 1-month versus longer DAPT strategies following PF-BES percutaneous coronary intervention (PCI).

Methods

FREEDOM is an all-comers registry including all patients who underwent PCI with at least one PF-BES at 10 sites, between January 2016 and July 2018. Patients were stratified according to DAPT strategy at discharge (1-month vs >1-month). Baseline features, reasons for PF-BES as reported by the treating physician, and outcomes were compared between groups. Primary outcomes were the 390-day estimates of a patient-oriented composite endpoint (POCE: death, myocardial infarction (MI) or target vessel revascularization) and of a device-oriented composite endpoint (DOCE: cardiac death, target vessel-MI or ischemia-driven target lesion revascularization). Incidence rates were adjusted for clinically relevant factors and outcome predictors. To avoid survival bias, landmark analyses starting from 1-month post-PCI were further carried.

Results

Following PF-BES PCI, 328 (40.3%) patients were discharged with 1-month DAPT and 485 (59.6%) patients with longer DAPT (median 12 months, IQR 6–12 months). Patients with hypertension or on oral anticoagulation (OAT) were more likely and patients with a previous or an index MI were less likely to be discharged on 1-month DAPT. Patients prescribed with 1-month DAPT were more likely to have had a PF-BES for a LEADERS FREE high bleeding risk criterium than those with longer DAPT (90.2% vs 69.9%, p=0.001). The same association was observed when the reason for PF-BES was a planned major surgery (13.1% vs 6.2%; p=0.001) or OAC to be continued after PCI (38.7% vs 16.5%, p<0.001). Conversely, patients with planned longer DAPT were more likely to have had a PF-BES following the operator preference (2.4% vs 15.5%, p<0.001) or for a reason other than a LEADERS FREE criterium or operator preference (5.2% vs 11.3%, p<0.001). No between-groups differences in the occurrence of the primary outcomes (1-month vs >1-month DAPT: POCE 11.9% vs 13.2%, p=0.747; adj-HR 1.29 [95% CI 0.78–2.10]; DOCE: 4.8% vs 8.1%, p=0.500; adj-HR 1.01 [95% CI 0.50–2.07]) and of bleedings (any: 11.3% vs 9.4%, p=0.472; adj-HR 0.87 [95% CI 0.51–1-50]; BARC 3–5: 4.2% vs 2.2%; p=0.108; adj-HR 1.50 [95% CI 0.58–3.87]) were observed. Landmark analyses showed similar results.

Conclusions

In a large contemporary all-comers registry, factors reflecting the operator-perceived patient high bleeding risk were the main drivers of a very-short DAPT strategy following PF-BES PCI. We found no interaction of DAPT duration with outcomes following PF-BES PCI, an observation warranting investigation in adequately powered randomised studies.

P2820Contemporary indications, dual antiplatelet therapy strategies and clinical outcomes for a polymer-free biolimus A9-coated stent: the all-comers FREEDOM registry

Background

The absence of a polymer-coat along with fast drug absorption represent the benchmark counterpart of the favourable clinical profile of a new polymer-free biolimus A9-eluting stent (PF-BES), also when used with a very short dual antiplatelet therapy (DAPT) strategy. Its current use in the real-world setting has not been thoroughly assessed.

Purpose

We evaluated contemporary patterns of indications, DAPT strategies and outcomes for the PF-BES.

Methods

FREEDOM is a multicenter registry including all patients who underwent percutaneous coronary intervention (PCI) with at least one PF-BES at 10 italian sites. Reasons for PF-BES PCI and planned antithrombotic regimen at discharge were collected. Primary outcomes were the 390-day Kaplan Meier estimates of a patient-oriented composite endpoint (POCE: death, any myocardial infarction [MI] or any target vessel revascularization [TVR]) and of a device-oriented composite endpoint (DOCE: cardiac death, target vessel-MI or ischemia-driven target lesion revascularization [ID-TLR]). The independent outcomes predictors were assessed through multivariate Cox proportional hazards analysis.

Results

Between January 2016 and July 2018, 858 patients (age: 74±10 years, 64.6% males, 58.7% acute coronary syndrome presentation) underwent PF-BES PCI. Main reasons for PF-BES physician's choice were advanced age (26.0%), oral anticoagulation (OAT) to be continued after PCI (25.3%), operator preference for PF-BES (9.9%), planned major surgery (8.6%), cancer (8.6%), anemia (7.9%) and recent bleeding (7.0%). Overall, the operator choice to implant a PF-BES reflected a perceived high bleeding risk in 77.7% of patients. At discharge, 99.2% of patients were on DAPT, 19.5% on triple therapy, and 0.8% on single antiplatelet therapy plus OAT. Planned DAPT duration was 1-month in 40.3% of patients, with 33.8% of these being on triple therapy. At 390-day follow-up (median 340 days, interquartile range: 187–390 days) the incident estimate of POCE was 13.1% (any MI 3.7%, any TVR 3.4%) and of DOCE was 7.1% (TV-MI 3.6%, ID-TLR 1.4%); while 390-day estimate of any bleeding event was 11.1% (BARC 3–5 bleeding 3.0%). Independent predictors of 390-day POCE were eGFR≤60 ml/min (HR 1.81; 95% CI 1.09–3.04, p=0.028), a history of cancer (HR 2.62; 95% CI 1.43–4.81, p=0.002) and severely calcified lesion/s (HR 2.05; 95% CI 1.09–3.85, p=0.025). Independent predictors of DOCE were a previous MI (HR 2.06; 95% CI 1.03–4.15, p=0.041), a history of cancer (HR 2.69; 95% CI 1.18–6.13, p=0.019) and bifurcation lesion/s (HR 2.66; 95% CI 1.38–5.13, p=0.004).

Conclusions

In a large, contemporary all-comers registry, the main reasons for PF-BES use reflected in most cases the operator-perceived high bleeding risk of the patient. Following PF-BES PCI, a very-short DAPT strategy was frequently implemented. The outcomes observed in this registry suggest a favorable safety and efficacy profile for the PF-BES in a real-world clinical setting.

Exome-wide assessment of the functional impact and pathogenicity of multinucleotide mutations

Approximately 2% of de novo single-nucleotide variants (SNVs) appear as part of clustered mutations that create multinucleotide variants (MNVs). MNVs are an important source of genomic variability as they are more likely to alter an encoded protein than a SNV, which has important implications in disease as well as evolution. Previous studies of MNVs have focused on their mutational origins and have not systematically evaluated their functional impact and contribution to disease. We identified 69,940 MNVs and 91 de novo MNVs in 6688 exome-sequenced parent–offspring trios from the Deciphering Developmental Disorders Study comprising families with severe developmental disorders. We replicated the previously described MNV mutational signatures associated with DNA polymerase zeta, an error-prone translesion polymerase, and the APOBEC family of DNA deaminases. We estimate the simultaneous MNV germline mutation rate to be 1.78 × 10⁻¹⁰ mutations per base pair per generation. We found that most MNVs within a single codon create a missense change that could not have been created by a SNV. MNV-induced missense changes were, on average, more physicochemically divergent, were more depleted in highly constrained genes (pLI ≥ 0.9), and were under stronger purifying selection compared with SNV-induced missense changes. We found that de novo MNVs were significantly enriched in genes previously associated with developmental disorders in affected children. This shows that MNVs can be more damaging than SNVs even when both induce missense changes, and are an important variant type to consider in relation to human disease.

Pathogenicity and selective constraint on variation near splice sites

Mutations that perturb normal pre-mRNA splicing are significant contributors to human disease. We used exome sequencing data from 7833 probands with developmental disorders (DDs) and their unaffected parents, as well as more than 60,000 aggregated exomes from the Exome Aggregation Consortium, to investigate selection around the splice sites and quantify the contribution of splicing mutations to DDs. Patterns of purifying selection, a deficit of variants in highly constrained genes in healthy subjects, and excess de novo mutations in patients highlighted particular positions within and around the consensus splice site of greater functional relevance. By using mutational burden analyses in this large cohort of proband–parent trios, we could estimate in an unbiased manner the relative contributions of mutations at canonical dinucleotides (73%) and flanking noncanonical positions (27%), and calculate the positive predictive value of pathogenicity for different classes of mutations. We identified 18 patients with likely diagnostic de novo mutations in dominant DD-associated genes at noncanonical positions in splice sites. We estimate 35%–40% of pathogenic variants in noncanonical splice site positions are missing from public databases.

Quantifying the contribution of recessive coding variation to developmental disorders

We estimated the genome-wide contribution of recessive coding variation in 6040 families from the Deciphering Developmental Disorders study. The proportion of cases attributable to recessive coding variants was 3.6% in patients of European ancestry, compared with 50% explained by de novo coding mutations. It was higher (31%) in patients with Pakistani ancestry, owing to elevated autozygosity. Half of this recessive burden is attributable to known genes. We identified two genes not previously associated with recessive developmental disorders, KDM5B and EIF3F, and functionally validated them with mouse and cellular models. Our results suggest that recessive coding variants account for a small fraction of currently undiagnosed nonconsanguineous individuals, and that the role of noncoding variants, incomplete penetrance, and polygenic mechanisms need further exploration.

Common genetic variants contribute to risk of rare severe neurodevelopmental disorders

There are thousands of rare human disorders that are caused by single deleterious, protein-coding genetic variants¹. However, patients with the same genetic defect can have different clinical presentations^2-4, and some individuals who carry known disease-causing variants can appear unaffected⁵. Here, to understand what explains these differences, we study a cohort of 6,987 children assessed by clinical geneticists to have severe neurodevelopmental disorders such as global developmental delay and autism, often in combination with abnormalities of other organ systems. Although the genetic causes of these neurodevelopmental disorders are expected to be almost entirely monogenic, we show that 7.7% of variance in risk is attributable to inherited common genetic variation. We replicated this genome-wide common variant burden by showing, in an independent sample of 728 trios (comprising a child plus both parents) from the same cohort, that this burden is over-transmitted from parents to children with neurodevelopmental disorders. Our common-variant signal is significantly positively correlated with genetic predisposition to lower educational attainment, decreased intelligence and risk of schizophrenia. We found that common-variant risk was not significantly different between individuals with and without a known protein-coding diagnostic variant, which suggests that common-variant risk affects patients both with and without a monogenic diagnosis. In addition, previously published common-variant scores for autism, height, birth weight and intracranial volume were all correlated with these traits within our cohort, which suggests that phenotypic expression in individuals with monogenic disorders is affected by the same variants as in the general population. Our results demonstrate that common genetic variation affects both overall risk and clinical presentation in neurodevelopmental disorders that are typically considered to be monogenic.

De novo mutations in regulatory elements in neurodevelopmental disorders

We previously estimated that 42% of patients with severe developmental disorders carry pathogenic de novo mutations in coding sequences. The role of de novo mutations in regulatory elements affecting genes associated with developmental disorders, or other genes, has been essentially unexplored. We identified de novo mutations in three classes of putative regulatory elements in almost 8,000 patients with developmental disorders. Here we show that de novo mutations in highly evolutionarily conserved fetal brain-active elements are significantly and specifically enriched in neurodevelopmental disorders. We identified a significant twofold enrichment of recurrently mutated elements. We estimate that, genome-wide, 1-3% of patients without a diagnostic coding variant carry pathogenic de novo mutations in fetal brain-active regulatory elements and that only 0.15% of all possible mutations within highly conserved fetal brain-active elements cause neurodevelopmental disorders with a dominant mechanism. Our findings represent a robust estimate of the contribution of de novo mutations in regulatory elements to this genetically heterogeneous set of disorders, and emphasize the importance of combining functional and evolutionary evidence to identify regulatory causes of genetic disorders.

Identification of genetic variants affecting vitamin D receptor binding and associations with autoimmune disease

Large numbers of statistically significant associations between sentinel SNPs and case-control status have been replicated by genome-wide association studies. Nevertheless, few underlying molecular mechanisms of complex disease are currently known. We investigated whether variation in binding of a transcription factor, the vitamin D receptor (VDR), whose activating ligand vitamin D has been proposed as a modifiable factor in multiple disorders, could explain any of these associations. VDR modifies gene expression by binding DNA as a heterodimer with the Retinoid X receptor (RXR). We identified 43,332 genetic variants significantly associated with altered VDR binding affinity (VDR-BVs) using a high-resolution (ChIP-exo) genome-wide analysis of 27 HapMap lymphoblastoid cell lines. VDR-BVs are enriched in consensus RXR::VDR binding motifs, yet most fell outside of these motifs, implying that genetic variation often affects the binding affinity only indirectly. Finally, we compared 341 VDR-BVs replicating by position in multiple individuals against background sets of variants lying within VDR-binding regions that had been matched in allele frequency and were independent with respect to linkage disequilibrium. In this stringent test, these replicated VDR-BVs were significantly (q < 0.1) and substantially (>2-fold) enriched in genomic intervals associated with autoimmune and other diseases, including inflammatory bowel disease, Crohn's disease and rheumatoid arthritis. The approach's validity is underscored by RXR::VDR motif sequence being predictive of binding strength and being evolutionarily constrained. Our findings are consistent with altered RXR::VDR binding contributing to immunity-related diseases. Replicated VDR-BVs associated with these disorders could represent causal disease risk alleles whose effect may be modifiable by vitamin D levels.

Most brain disease-associated and eQTL haplotypes are not located within transcription factor DNase-seq footprints in brain

Dense genotyping approaches have revealed much about the genetic architecture both of gene expression and disease susceptibility. However, assigning causality to genetic variants associated with a transcriptomic or phenotypic trait presents a far greater challenge. The development of epigenomic resources by ENCODE, the Epigenomic Roadmap and others has led to strategies that seek to infer the likely functional variants underlying these genome-wide association signals. It is known, for example, that such variants tend to be located within areas of open chromatin, as detected by techniques such as DNase-seq and FAIRE-seq. We aimed to assess what proportion of variants associated with phenotypic or transcriptomic traits in the human brain are located within transcription factor binding sites. The bioinformatic tools, Wellington and HINT, were used to infer transcription factor footprints from existing DNase-seq data derived from central nervous system tissues with high spatial resolution. This dataset was then employed to assess the likely contribution of altered transcription factor binding to both expression quantitative trait loci (eQTL) and genome-wide association study (GWAS) signals. Surprisingly, we show that most haplotypes associated with GWAS or eQTL phenotypes are located outside of DNase-seq footprints. This could imply that DNase-seq footprinting is too insensitive an approach to identify a large proportion of true transcription factor binding sites. Importantly, this suggests that prioritising variants for genome engineering studies to establish causality will continue to be frustrated by an inability of footprinting to identify the causative variant within a haplotype.

Foxn1 regulates key target genes essential for T cell development in postnatal thymic epithelial cells

Thymic epithelial cell differentiation, growth and function depend on the expression of the transcription factor Foxn1, however its target genes have never been physically identified. Using novel static and inducible genetic model systems and chromatin studies, we provide now a genome wide map of direct Foxn1 target genes for postnatal thymic epithelia and define the Foxn1 binding motif. We detail the function of Foxn1 in these cells and demonstrate that in addition to the transcriptional control of genes involved in the attraction and lineage commitment of T cell precursors, Foxn1 regulates the expression of genes involved in antigen processing and thymocyte selection. Thus, critical events in thymic lympho-stromal cross-talk and T cell selection are indispensably choreographed by Foxn1.

Cardiac Rhythm Monitoring After Acute Decompensation for Heart Failure: Results from the CARRYING ON for HF Pilot Study

Background

There’s scarce evidence about cardiovascular events (CV) in patients with hospitalization for acute heart failure (HF) and no indication for immediate device implant.

Objective

The CARdiac RhYthm monitorING after acute decompensatiON for Heart Failure study was designed to assess the incidence of prespecified clinical and arrhythmic events in this patient population.

Methods

In this pilot study, 18 patients (12 (67%) male; age 72±10; 16 (89%) NYHA II-III), who were hospitalized for HF with low left ventricular ejection fraction (LVEF) (<40%) and no immediate indication for device implant received an implantable loop recorder (ILR) before hospital discharge. Follow-up visits were scheduled at 3 and 6 months, and at every 6 months until study closure; device data were remotely reviewed monthly. CV mortality, unplanned CV hospitalization, and major arrhythmic events during follow-up were analyzed.

Results

During a median follow-up of 593 days, major CV occurred in 13 patients (72%); of those, 7 patients had at least 1 cardiac arrhythmic event, 2 had at least a clinical event (CV hospitalization or CV death), and 4 had both an arrhythmic and a CV event. Six (33%) patients experienced 10 major clinical events, 5 of them (50%) were HF related. During follow-up, 2 (11%) patients died due to a CV cause and 3 (16%) patients received a permanent cardiac device.

Conclusions

After an acute HF hospitalization, patients with LVEF<40% and who are not readily eligible for permanent cardiac device implant have a known high incidence of major CV event. In these patients, ILR allows early detection of major cardiac arrhythmias and the ability to react appropriately in a timely manner.

Trial Registration

ClinicalTrials.gov NCT01216670; https://clinicaltrials.gov/ct2/show/NCT01216670

Mutations in ZMYND10, a gene essential for proper axonemal assembly of inner and outer dynein arms in humans and flies, cause primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a ciliopathy characterized by airway disease, infertility, and laterality defects, often caused by dual loss of the inner dynein arms (IDAs) and outer dynein arms (ODAs), which power cilia and flagella beating. Using whole-exome and candidate-gene Sanger resequencing in PCD-affected families afflicted with combined IDA and ODA defects, we found that 6/38 (16%) carried biallelic mutations in the conserved zinc-finger gene BLU (ZMYND10). ZMYND10 mutations conferred dynein-arm loss seen at the ultrastructural and immunofluorescence level and complete cilia immotility, except in hypomorphic p.Val16Gly (c.47T>G) homozygote individuals, whose cilia retained a stiff and slowed beat. In mice, Zmynd10 mRNA is restricted to regions containing motile cilia. In a Drosophila model of PCD, Zmynd10 is exclusively expressed in cells with motile cilia: chordotonal sensory neurons and sperm. In these cells, P-element-mediated gene silencing caused IDA and ODA defects, proprioception deficits, and sterility due to immotile sperm. Drosophila Zmynd10 with an equivalent c.47T>G (p.Val16Gly) missense change rescued mutant male sterility less than the wild-type did. Tagged Drosophila ZMYND10 is localized primarily to the cytoplasm, and human ZMYND10 interacts with LRRC6, another cytoplasmically localized protein altered in PCD. Using a fly model of PCD, we conclude that ZMYND10 is a cytoplasmic protein required for IDA and ODA assembly and that its variants cause ciliary dysmotility and PCD with laterality defects.

Vitamin D receptor ChIP-seq in primary CD4+ cells: relationship to serum 25-hydroxyvitamin D levels and autoimmune disease

BACKGROUND

Vitamin D insufficiency has been implicated in autoimmunity. ChIP-seq experiments using immune cell lines have shown that vitamin D receptor (VDR) binding sites are enriched near regions of the genome associated with autoimmune diseases. We aimed to investigate VDR binding in primary CD4+ cells from healthy volunteers.

METHODS

We extracted CD4+ cells from nine healthy volunteers. Each sample underwent VDR ChIP-seq. Our results were analyzed in relation to published ChIP-seq and RNA-seq data in the Genomic HyperBrowser. We used MEMEChIP for de novo motif discovery. 25-Hydroxyvitamin D levels were measured using liquid chromatography-tandem mass spectrometry and samples were divided into vitamin D sufficient (25(OH)D ≥75 nmol/L) and insufficient/deficient (25(OH)D <75 nmol/L) groups.

RESULTS

We found that the amount of VDR binding is correlated with the serum level of 25-hydroxyvitamin D (r = 0.92, P= 0.0005). In vivo VDR binding sites are enriched for autoimmune disease associated loci, especially when 25-hydroxyvitamin D levels (25(OH)D) were sufficient (25(OH)D ≥75: 3.13-fold, P<0.0001; 25(OH)D <75: 2.76-fold, P<0.0001; 25(OH)D ≥75 enrichment versus 25(OH)D <75 enrichment: P= 0.0002). VDR binding was also enriched near genes associated specifically with T-regulatory and T-helper cells in the 25(OH)D ≥75 group. MEME ChIP did not identify any VDR-like motifs underlying our VDR ChIP-seq peaks.

CONCLUSION

Our results show a direct correlation between in vivo 25-hydroxyvitamin D levels and the number of VDR binding sites, although our sample size is relatively small. Our study further implicates VDR binding as important in gene-environment interactions underlying the development of autoimmunity and provides a biological rationale for 25-hydroxyvitamin D sufficiency being based at 75 nmol/L. Our results also suggest that VDR binding in response to physiological levels of vitamin D occurs predominantly in a VDR motif-independent manner.

CRACK GROWTH BEHAVIOR OF STYRENE-BUTADIENE RUBBER, NATURAL RUBBER, AND POLYBUTADIENE RUBBER COMPOUNDS: COMPARISON OF PURE-SHEAR VERSUS STRIP TENSILE TEST

Fatigue crack growth experiments on different carbon black–filled rubber compounds have been carried out to evaluate the influence of pure-shear and strip tensile testing mode by using sine and pulse as waveforms. In a previous set of experimental investigations regarding the influence of both waveform and tested material, it was found that the mode I of crack opening sometimes propagates too quickly to be properly monitored in tests involving strip-tensile specimens. An alternative test methodology based on pure-shear test mode has been investigated, optimizing both the shape of the specimen and the test equipment. Data obtained from the different compound formulations were consistent with the theoretical background and resulted in similar ranking of compound crack growth resistance for the two testing modes; in addition, pure-shear mode showed a higher sensitivity to formula variations.