Predictability and durability of mitral valve repair in patients with severe degenerative mitral regurgitation in medium sized centres

INTRODUCTION

Mitral valve repair (MVr) is now the treatment of choice to correct severe degenerative mitral regurgitation (MR). Repair rates vary greatly from centre to centre, and the concept of heart valve centres of excellence has been established.

OBJECTIVE

The purpose of this study was to see whether large international centre repair rates, and outcomes, are transferrable to medium-sized centres with an interest in mitral repair.

METHODS

Between 2011 and 2018, a total of 346 patients underwent mitral valve surgery by a single surgeon. Of these, 238 consecutive patients had repairs, or attempted repairs for degenerative MR, and are included in this study.

RESULTS

The study sample consisted of 71% male patients and had a mean age of 64.4 ± 12.3 years; 66% of the study population had concomitant procedures. The overall repair rate in this cohort is 99%. Mean follow up was 3.7 ± 1.9 years. At 5 years, the freedom from MR ≥ 3+ was 95.9 ± 1.9% and at 7 years 91.1 ± 3.8%. Freedom from reoperation at 5 years was 92.9 ± 3.7%, while the 5 years actuarial survival was 89.1 ± 3.7%. On a multivariate analysis, predischarge echo grade was associated with higher risk of future reoperation (odds ratio (OR) = 21.82, p = 0.05). Only age (OR = 1.3, p = 0.03) was predictive of long-term survival.

CONCLUSIONS

In specialised medium-sized heart centres, where the surgical team have undergone specialist mitral training, favourable short- and long-term outcomes are achievable with mitral repair rates similar to those from large international centres of excellence. In these heart centres, early surgery should be considered for all patients with severe degenerative MR.

247 QUALITY IMPROVEMENT IN DEMENTIA CARE: STREAMLINING CARE PATHWAYS IN A PSYCHIATRY OF OLD AGE SERVICE

Background

Dementia is increasingly considered a public health priority worldwide in the context of predicted increased prevalence. In Ireland, there are an estimated 67,000 persons living with dementia and by 2041 it is expected to rise to 145,000 persons. Challenges in dementia care have been highlighted in health services across Europe and the ineffective structure of dementia care with fragmented non-person-centred pathways has been identified.

Methods

An initial review of the existing cognitive impairment diagnostic pathways in our specialised Psychiatry of Old Age (POA) Service was undertaken. This included surveying the multidisciplinary team to identify challenges, clinical chart review and audit of physical examination equipment. Diagnostic pathway was updated based on findings and informed by the developing national ‘Model of Care for Dementia in Ireland’ and best practice.

Results

Review findings included lack of standardisation of memory assessment, delays in accessing neuroimaging and laboratory results, gaps in staff training. A care pathway document was developed detailing requirements for care from the point of referral through to cognitive impairment diagnosis. Staff training was completed to accompany the introduction of standardised dementia assessment scales. Access to laboratory/radiology booking was enhanced. A cognitive remediation group was developed by Occupational Therapy as part of post-diagnostic supports for service users. Preliminary data indicates improvements in satisfaction of those attending the group. Physical examination equipment audit resulted in quality improvements.

Conclusion

We demonstrate that a quality improvement approach can be implemented to enhance assessment, diagnosis and care provided to support diagnosis of cognitive impairment and dementia in POA service. The enhanced diagnostic care pathways will be assessed over time to assess impact on care of service users. Preliminary findings are positive and it is an approach that can be adopted in other services and inform development of national memory service developments.

Consenting practices in interventional cardiology: an analysis from the European Association of Percutaneous Cardiovascular Interventions (EAPCI)

Background

Consenting practices in interventional cardiology vary across different procedures, operators, centres and nations.

Purpose

In order to define best practice for obtaining informed patient consent, it is first necessary to understand how consenting practice differs.

Methods

An online survey of 20 questions was sent to all members of the European Association of Percutaneous Cardiovascular Interventions, addressing consenting practices in elective and emergency scenarios.

Results

We received 483 responses from 74 countries. The majority of respondents (77%) were European operators. Responses were received from consultant cardiologists (n=370), fellows in training (n=55), allied health professionals (n=36) and others (n=21).

Across all respondents, in elective practice, 427 (88.4%) operators obtain written consent for every procedure, the remainder (9.5%) obtain verbal consent only. Consent is obtained by the consultant or fellow who directly performs the procedure in 56.9% cases. For coronary angiography, pre-emptive consent for possible additional procedures (pressure wire and PCI) is taken by operators in all cases (58.6%), some cases (30.6%) and never (11.0%). Prior to interventional therapies, written information detailing the risk of the procedure is provided in every case by 63.8% of operators, sometimes by 25.1% of operators, and is never provided by 11.0% of operators.

In emergency settings, where patients are conscious and have capacity to consent, 274 (56.7%) of respondents obtain written consent, 155 (33.1%) obtain verbal consent only and 52 (10.8%) stated that a consent process was not required. Where consciousness and capacity are impaired, 218 (45.1%) always, 118 (24.4%) sometimes and 145 (30%) never document a written capacity and best interests' assessment.

When asked to rate the overall quality of consenting practices in their own institution, 279 (57.8%) stated these were “excellent” or “above average”, 165 (34.2%) were “average” and 39 operators described consenting practices in their institution as “below average” or “poor”.

Conclusions

Diversity in consenting practice spans elective and emergency procedures. These results suggest that there is substantial variation in the understanding of the rationale, legal requirement, and perceived best practices for consent. Further work should consider the merits of standardisation of consent processes across Europe.

Funding Acknowledgement

Type of funding sources: None.

European position paper on the management of patients with patent foramen ovale. Part II - Decompression sickness, migraine, arterial deoxygenation syndromes and select high-risk clinical conditions

Patent foramen ovale (PFO) is implicated in the pathogenesis of a number of medical conditions but to date only one official position paper related to left circulation thromboembolism has been published. This interdisciplinary paper, prepared with the involvement of eight European scientific societies, reviews the available evidence and proposes a rationale for decision making for other PFO-related clinical conditions. In order to guarantee a strict evidence-based process, we used a modified grading of recommendations, assessment, development, and evaluation (GRADE) methodology. A critical qualitative and quantitative evaluation of diagnostic and therapeutic procedures was performed, including assessment of the risk/benefit ratio. The level of evidence and the strength of the position statements were weighed and graded according to predefined scales. Despite being based on limited and observational or low-certainty randomised data, a number of position statements were made to frame PFO management in different clinical settings, along with suggestions for new research avenues. This interdisciplinary position paper, recognising the low or very low certainty of existing evidence, provides the first approach to several PFO-related clinical scenarios beyond left circulation thromboembolism and strongly stresses the need for fresh high-quality evidence on these topics.

Optical Coherence Tomography Assessment in Patients Treated With Rotational Atherectomy Versus Modified Balloons: PREPARE-CALC OCT

[Figure: see text].

The Feeding Practices and Structure Questionnaire: development and validation of age appropriate versions for infants and toddlers

Background

In order to measure and understand trajectories of parental feeding practices and their relationship with child eating and weight, it is desirable to perform assessment from infancy and across time, in age-appropriate ways. While many feeding practices questionnaires exist, none is presently available that enables tracking of feeding practices from infancy through childhood. The aim of the study was to develop a version of the Feeding Practices and Structure Questionnaire (FPSQ) for parents with infants and toddlers (< 2 years) to be used in conjunction with the original FPSQ for older children (≥2 years) to measure feeding practices related to non-responsiveness and structure across childhood.

Methods

Constructs and items for the FPSQ for infants and toddlers were derived from the existing and validated FPSQ for older children and supplemented by a review of the literature on infant feeding questionnaires. Following expert review, two versions of the questionnaire were developed, one for milk feeding parents and one for solid feeding parents. Data from two studies were combined (child ages 0–24 months) to test the derived constructs with Confirmatory Factor Analysis for the milk feeding (N = 731) and solid feeding (N = 611) versions.

Results

The milk feeding version consisted of four factors (18 items) and showed acceptable model fit and good internal reliability: ‘feeding on demand vs. feeding routine’ (α = 0.87), ‘using food to calm’ (α = 0.87), ‘persuasive feeding’ (α = 0.71), ‘parent-led feeding’ (α = 0.79). The same four factors showed acceptable model fit for the solid feeding version (21 items), likewise with good internal reliability (α = 0.74, 0.86, 0.85, 0.84 respectively). Two additional factors (13 items) were developed for the solid feeding version that appeared developmentally appropriate only for children aged 12 months or older: ‘family meal environment’ (α = 0.81) and ‘using (non-)food rewards’ (α = 0.92). The majority of factor-factor correlations were in line with those of the original FPSQ.

Conclusions

The FPSQ milk and solid feeding versions are the first measures specifically developed as precursors to the FPSQ to measure parental feeding practices in children < 2 years, particularly practices related to non-responsiveness and structure. Further validation in more diverse samples is required.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-021-01079-x.

Beyond-use Date of Trimix: A Reproducible Stability Study Using Bracketing Design

Trimix is a widely prescribed penile injection for patients with erectile dysfunction and is only available as a compounded medication. The instability of alprostadil, one of the major ingredients of Trimix, has been a limiting factor in its utilization. There are published stability data for Trimix formulations that have been used to establish a beyond-use-date. However, a robust bracketed study that is shown to be reproducible is highly desirable and meaningful. The purpose of this study was to test the reproducibility of a bracketed stability study when the preparations were made by two different entities to provide beyond-use date information of Trimix preparations that cover a wide range of strengths. A validated stability indicating method was used to compare the stability of a bracketed Trimix - alprostadil 5 µg/mL to 45 µg/mL, papaverine 15 mg/mL to 30 mg/mL, and phentolamine 0.4 mg/mL to 5 mg/mL, and a single-strength preparation containing alprostadil 30 µg/mL, papaverine 30 mg/mL, and phentolamine 2 mg/mL that were compounded and stored following the same methods and conditions, but at two different practice settings. Beyond-use dates of 60 days and 64 days at cold temperature were obtained for the two preparations from two different settings. The consistent results confirmed the reproducibility of the bracketing designs used to determine the beyond-use dates of Trimix. The clinical value of these results stems from the availability of accurate and widely applicable stability data that can be referenced to establish beyond use dates of a number of Trimix preparations with various strength combinations.

Mechanism of Drug-Eluting Absorbable Metal Scaffold Restenosis

Background:

The pathomechanisms underlying restenosis of the bioabsorbable sirolimus-eluting metallic scaffold (Magmaris) remain unknown. Using serial optical coherence tomography, we investigated causes of restenosis, including the contribution of late scaffold recoil versus neointimal hyperplasia.

Methods:

Patients enrolled in BIOSOLVE-II undergoing serial angiography and optical coherence tomography (post-intervention and follow-up: 6 months and/or 1 year) were analyzed. Patients were divided into 2 groups according to angiographic in-scaffold late lumen loss (LLL) <0.5 or ≥0.5 mm. End points were late absolute scaffold recoil and neointimal hyperplasia area as assessed by optical coherence tomography.

Results:

Serial data were available for analysis from 70 patients (LLL <0.5 mm: n=41; LLL ≥0.5 mm: n=29). Patient and lesion characteristics were comparable, and there was no significant difference in mean and minimal scaffold area between groups at post-intervention. Late absolute scaffold recoil was less among patients with LLL <0.5 mm (0.53±0.68 mm 2 ) compared with those with LLL ≥0.5 mm (1.48±1.20 mm 2 ; P <0.001). Neointimal hyperplasia area was smaller among patients with LLL <0.5 mm at follow-up (1.47±0.33 mm 2 ) compared with patients with LLL ≥0.5 mm (1.68±0.34 mm 2 ; P =0.013). In a matched-frame analysis (post-intervention and follow-up), late absolute scaffold recoil varied according to the underlying plaque type (lipid: 0.63±1.23 mm 2 ; calcified: 0.81±1.44 mm 2 ; and fibrous: 1.20±1.52 mm 2 ; P <0.001), while there was no difference with regards to neointimal hyperplasia area ( P =0.132).

Conclusions:

In addition to neointimal hyperplasia, late scaffold recoil contributed significantly to LLL of sirolimus-eluting absorbable metal scaffolds. The extent of late scaffold recoil was dependent on the underlying plaque morphology and was the highest among fibrotic lesions.

Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01960504.

Introducing the CSP Analyzer: A novel Machine Learning-based application for automated analysis of two-dimensional NMR spectra in NMR fragment-based screening

NMR-based screening, especially fragment-based drug discovery is a valuable approach in early-stage drug discovery. Monitoring fragment-binding in protein-detected 2D NMR experiments requires analysis of hundreds of spectra to detect chemical shift perturbations (CSPs) in the presence of ligands screened. Computational tools are available that simplify the tracking of CSPs in 2D NMR spectra. However, to the best of our knowledge, an efficient automated tool for the assessment and binning of multiple spectra for ligand binding has not yet been described. We present a novel and fast approach for analysis of multiple 2D HSQC spectra based on machine-learning-driven statistical discrimination. The CSP Analyzer features a C# frontend interfaced to a Python ML classifier. The software allows rapid evaluation of 2D screening data from large number of spectra, reducing user-introduced bias in the evaluation. The CSP Analyzer software package is available on GitHub https://github.com/rubbs14/CSP-Analyzer/releases/tag/v1.0 under the GPL license 3.0 and is free to use for academic and commercial uses.

P6138Quality of clinical trial evidence on devices and drugs approved to treat coronary artery disease

Background

Regulatory approval of drugs and devices follow two different pathways. Whether different approval pathways underlie meaningful differences in quality of clinical trial evidence is unknown. We aimed to compare the quality of evidence of clinical trials that served as a basis for approval by the U.S. Food and Drug Administration (FDA) of drugs and devices used for the treatment of coronary artery disease.

Methods

FDA databases were searched for devices (i.e., coronary artery drug-eluting stents) and drugs (i.e., agents targeting atherothrombosis) approved between January 1st, 2001 and December 31st, 2017. FDA medical reviews were screened to identify trials that served for approval purposes. The pre-specified primary outcome was the prevalence of randomized trials used for approval (i.e. number of randomized trials/overall number of trials).

Results

A total of 97 trials were identified, 39 serving for approval of 13 devices and 58 serving for approval of 8 drugs. Devices were evaluated by fewer trials per item as compared with drugs (3.0±1.4 vs. 7.3±5.3, P=0.012) with similar study size (501 [100–1314] vs. 379 [183–904] patients per trial, P=0.55). Trials evaluating devices were less frequently randomized (56.4% vs. 94.8%, P<0.001) and more frequently designed powered for clinical endpoints (53.8% vs. 17.2%, P<0.001) as compared to those evaluating drugs. Use of randomization declined over time among trials supporting FDA approval of devices. In addition, significant differences were present between trials evaluating devices and those evaluating drugs in terms of study design, comparator used, blinding to treatment allocation, primary hypothesis, primary endpoint, and type of patients included.

Use of randomized trials for approval

Conclusions

There are substantial differences in clinical trial evidence serving for FDA approval of devices and drugs used for treatment of coronary artery disease. The lower degree of randomized evidence used for approval of devices as compared to drugs raises some concerns, particularly in view of its decline over time.

122Mechanism and impact of lesion morphology on the late lumen loss of drug-eluting resorbable magnesium scaffolds: a serial optical coherence tomography study

Introduction

Resorbable Magnesium Scaffolds have demonstrated favourable clinical results with acceptable late lumen loss (LLL). However, the pathomechanisms influencing LLL of resorbable sirolimus-eluting metallic scaffold (Magmaris) have not been analyzed.

Purpose

Using serial optical coherence tomography (OCT), we investigated potential factors, i.e. the contribution of recoil versus neointimal hyperplasia (NIH).

Methods

Patients who were enrolled into BIOSOLVE-II, and underwent serial angiography and OCT (baseline and follow-up: 6-month and/or 1-year) were analyzed. Patients were divided into 2 groups based on angiographic in-scaffold LLL <0.5mm or ≥0.5mm. Endpoints were late absolute recoil and NIH area as assessed by OCT.

Results

A total of 70 patients (LLL <0.5mm: n=41, LLL ≥0.5mm: n=29) were serially analyzed. Patient and lesion characteristics were comparable and there was no significant difference in mean and minimal scaffold area between groups at baseline. Late absolute recoil was significantly smaller among patients with LLL <0.5mm (0.53±0.68 mm2) compared with those with LLL ≥0.5mm (1.48±1.20 mm2, P<0.001) (Figure). A small difference in NIH area at follow-up was observed (LLL <0.5mm: 1.47±0.33 mm2 vs. LLL ≥0.5mm: 1.68±0.34 mm2, P=0.013). In a matched-frame analysis (baseline and follow-up), late absolute recoil varied according to the underlying plaque type (lipid: 0.63±1.23 mm2, calcified: 0.81±1.44 mm2, and fibrous: 1.20±1.52 mm2, P<0.001), while there was no difference with regards to NIH area (P=0.132).

Conclusion

The main driver of late lumen loss of sirolimus-eluting absorbable metal scaffold was late scaffold recoil, while the contribution of NIH was modest. The degree of late scaffold recoil depended on the underlying plaque type and was highest among fibrotic lesions. Future studies will address the impact of procedural factors such as adequate lesion preparation and post-dilatation.

Acknowledgement/Funding

Biotronik

An examination of children's eating behaviours as mediators of the relationship between parents' feeding practices and early childhood body mass index z-scores

OBJECTIVE

Parent's use of restrictive feeding practices is associated with child weight. Similarly, the literature shows that children's eating behaviours are also associated with child weight. Given this interrelationship between children's eating behaviours, restrictive feeding practices and child weight, examination of possible mediator relationships is warranted. This study aimed to examine the relationships between overt restriction and covert restriction with child body mass index z-scores (BMIz) and determine if children's eating behaviours (satiety responsiveness and food responsiveness) act as mediators.

METHOD

Parents of Australian children (n = 977) 2.0-5.0 years of age (49.4% male) provided data in an online survey on child eating behaviours, parent's restrictive feeding practices and child anthropometrics (modified z-scores were created to screen for biologically implausible values). Correlation analysis was used to determine variables to include in mediation models. Hayes' PROCESS macros in spss was used to examine mediation, controlling for covariates of child BMIz.

RESULTS

Overt restriction was the only parent feeding practice related to child BMIz (B = 0.132, P = 0.04). Mediation analysis showed that the indirect effect of overt restriction on child BMIz (controlling for child age, gender, parent BMI and income) became non-significant when controlling for food responsiveness, thus suggesting full mediation, explaining 5.75% of the relation.

CONCLUSION

Overt restriction and covert restriction have distinctly different relationships with children's eating behaviours. Food responsiveness appears an important intermediary in the relationship between overt restriction and child BMIz.

European position paper on the management of patients with patent foramen ovale. General approach and left circulation thromboembolism

The presence of a patent foramen ovale (PFO) is implicated in the pathogenesis of a number of medical conditions; however, the subject remains controversial and no official statements have been published. This interdisciplinary paper, prepared with involvement of eight European scientific societies, aims to review the available trial evidence and to define the principles needed to guide decision making in patients with PFO. In order to guarantee a strict process, position statements were developed with the use of a modified grading of recommendations assessment, development, and evaluation (GRADE) methodology. A critical qualitative and quantitative evaluation of diagnostic and therapeutic procedures was performed, including assessment of the risk/benefit ratio. The level of evidence and the strength of the position statements of particular management options were weighed and graded according to predefined scales. Despite being based often on limited and non-randomised data, while waiting for more conclusive evidence, it was possible to conclude on a number of position statements regarding a rational general approach to PFO management and to specific considerations regarding left circulation thromboembolism. For some therapeutic aspects, it was possible to express stricter position statements based on randomised trials. This position paper provides the first largely shared, interdisciplinary approach for a rational PFO management based on the best available evidence.

Serum NGAL can act as an early renal safety biomarker during long-term nucleos(t)ide analogue antiviral therapy in chronic hepatitis B

Tubular renal toxicity is a side-effect of long-term therapy with nucleos(t)ide analogue(s) (NA) in chronic hepatitis B (CHB). There are no established surrogate markers in plasma of early NA-related toxicity. Neutrophil gelatinase-associated lipocalin (NGAL) is a protein produced by tubular cells following renal damage. We aimed therefore to retrospectively compare conventional renal markers (estimated glomerular filtration rates (eGFR) and urinary protein/creatinine ratio uPCR) with a sensitive biomarker (NGAL) in CHB patients on long-term NA therapy and assess the ability of new markers to predict NA-related renal toxicity (new onset of nonalbumin proteinuria). A total of 192 naïve CHB patients (median age 41 years, 78% males, 25% HBeAg+, 35% cirrhosis) were NA treated for at least 5 years (median 8.34 years, range 5.54-11.1 years). The eGFR and uPCR were compared at baseline and last clinical visit with serum NGAL concentrations measured by ELISA at same time-points and assessed according to the presence/absence of nonalbumin proteinuria at last visit. While baseline and last visit eGFR were similar (median:78 vs 84 mL/min), serum NGAL concentrations increased during therapy (median:9.4 vs 16.4 ng/mL, P < .05). The proportion of patients with proteinuria (uPCR > 15) increased between baseline and last visit (4.6% vs 21.4%, P < .05), with 30 (16%) patients having de novo nonalbumin proteinuria at last visit. High baseline NGAL concentrations were exclusive to patients with de novo nonalbumin proteinuria (median:31.7 vs 7.8 ng/mL, P < .01) and baseline NGAL levels >25 mg/mL were predictive of nonalbumin proteinuria at last visit (AUROC = 0.813). In conclusion, serum NGAL can act as a surrogate marker of early renal injury (de novo nonalbumin proteinuria) in CHB on long-term NA therapy.

Comparative assessment of drug-eluting balloons in an advanced porcine model of coronary restenosis

The advent of drug-eluting balloon (DEB) therapy has represented an important development in interventional cardiology. Nevertheless, pre-clinical data with this technology remain scant, and comparative studies have not previously been published. Bare metal stents were implanted in the coronary arteries of 15 pigs followed by balloon angioplasty. Animals were allocated to treatment with a 60-second inflation of one of four different balloon catheters: a conventional untreated plain angioplasty balloon (PBA, Biotronik AG), the Pantera Lux DEB (3.0 μg/mm2 paclitaxel; BTHC excipient, Biotronik AG), the Elutax DEB (2.0 μg/mm2 paclitaxel; no excipient; Aachen Resonance), or the SeQuent Please DEB (3.0 μg/mm2 paclitaxel; iopromide excipient: B. Braun). Twenty-eight days following balloon deployment, animals underwent repeat angiography for quantitative coronary angiography analysis and euthanasia for histopathologic assessment. By histology, the mean neointimal thickness was 0.44 ± 0.19 mm with PBA, 0.35 ± 0.13 mm with Pantera Lux, 0.61 ± 0.20 mm with Elutax, and 0.47 ± 0.21 mm with SeQuent Please DEB (p=0.02). In comparison with PBA, deployment of the Pantera Lux or the SeQuent Please DEB resulted in delayed healing characterised by significant increases in fibrin, neointimal cell vacuity and delayed re-endothelialisation. In conclusion, investigation of comparative DEB performance in a porcine model of advanced coronary restenosis reveals significant heterogeneity of neointimal suppression between the devices tested with numerically lowest values seen in the Pantera Lux group. On the other hand, evidence of delayed healing was observed in the most effective DEB groups.

Risk of drug-eluting stent thrombosis in patients receiving proton pump inhibitors

Clopidogrel is a prodrug that is converted via the hepatic cytochrome P450 system into its active thiol metabolite. Evidence is accumulating that proton pump inhibitors (PPIs) inhibit this enzymatic pathway and may therefore attenuate the antiplatelet effect of clopidogrel. The objective of this study was to investigate whether patients on clopidogrel therapy after drug-eluting stent (DES) placement who also receive a PPI are at higher risk of stent thrombosis (ST). This is a retrospective analysis of patients who received dual antiplatelet treatment including clopidogrel after DES placement. Outcomes were compared according to PPI therapy. The primary endpoint was the incidence of definite ST at 30 days. Secondary endpoints were death, combined death or ST and myocardial infarction (MI). The study population included 3,338 patients and 698 patients (20.9%) received PPIs. Patients receiving a PPI had a higher risk profile at baseline. Multivariate analysis showed that PPI treatment was not independently associated with the occurrence of ST [adjusted HR 1.8 (95% CI: 0.7–4.7), p=0.23] or MI [adjusted HR 1.3 (0.8–2.3), p=0.11]. PPI treatment was significantly associated with death [adjusted HR 2.2 (1.1–4.3), p=0.02] and death or ST [adjusted HR 3.3(1.7–6.7), p=0.02]. Concomitant treatment with a PPI in patients receiving dual antiplatelet treatment after coronary stenting is not an independent predictor of ST. The higher mortality is probably due to confounding as patients on PPIs had a higher risk profile at baseline.

Activity-Based Probes for HECT E3 Ubiquitin Ligases

Activity‐based probes (ABPs) have been used to dissect the biochemical/structural properties and cellular functions of deubiquitinases. However, their utility in studying cysteine‐based E3 ubiquitin ligases has been limited. In this study, we evaluate the use of ubiquitin‐ABPs (Ub‐VME and Ub‐PA) and a novel set of E2–Ub‐ABPs on a panel of HECT E3 ubiquitin ligases. Our in vitro data show that ubiquitin‐ABPs can label HECT domains. We also provide the first evidence that, in addition to the RBR E3 ubiquitin ligase Parkin, E2–Ub‐ABPs can also label the catalytic HECT domains of NEDD4, UBE3C, and HECTD1. Importantly, the endogenous proteasomal E3 ligase UBE3C was also successfully labelled by Ub‐PA and His‐UBE2D2–Ub‐ABP in lysate of cells grown under basal conditions. Our findings provide novel insights into the use of ABPs for the study of HECT E3 ubiquitin ligases.