P5430Long term outcomes of patients receiving Implantable Cardioverter Defibrillators in a contemporary implant population in the Essex region of the UK

Introduction

Implantable cardioverter-defibrillators (ICD) reduce the risk of sudden cardiac death in patients who are at risk and amongst among heart failure (HF) patients with a reduced left ventricular ejection fraction (LVEF).

Objective

The aim of this study was to determine the differences in outcomes amongst patients in a contemporary ICD implant population based on primary or secondary indications and an ischaemic or non-ischaemic aetiology. The primary outcome was death or appropriate device therapy for a ventricular arrhythmia. The secondary outcome was inappropriate shock therapy.

Purpose

The study cohort included consecutive patients who had an ICD or CRT-D implanted at a high-volume regional referral centre in Essex between 2014 and 2015. The censor point for follow up was 31/12/2018. Cumulative incidences were analysed by the method of Kaplan–Meier and compared using the log-rank test. In addition, the relationship between several clinical variables were tested in a multivariate Cox model to predict long-term mortality and this is described with hazard ratios (HR) and 95% CI.

Results

407 patients who received ICD treatment were followed up for a mean of 50±4 months. 63% had an Ischaemic cardiomyopathy and 60% had a primary prevention indication. Majority were men (81.5%), mean LVEF was (31±11) and mean age (71±11). The incidence of appropriate ICD therapy at 1-year post ICD insertion was 6.8% in all patients. This was significantly higher in patients with a secondary prevention indication compared to primary prevention (11.7% v 3.6% p=0.015) but similar in ischaemic compared to non-ischaemic patients (7.8% v 5.2% p=0.46). 1.9% patients had an inappropriate shock at 1 year and between group rate was similar. Overall 8.1% of patients did not survive beyond 1-year post implant with a mean time to death of 5.6±3.6 months. The cumulative incidence of the primary end-point at 1 year was similar in ischaemic and non-Ischaemic patients (7.8% v 8.6%; HR: 1.04, 95% CI 0.7–1.5, p=0.83) but was significantly higher at the end of study period in patients with an ischaemic aetiology (32.4% v 21%; HR: 1.59, 95% CI: 1.1–2.4, p=0.024) (Fig.1). In an adjusted Cox Hazard model, appropriate ICD therapy at 1 year (HR: 0.28, 95% CI: 0.17–0.47, p<0.001) and a secondary indication for ICD treatment (HR: 0.47, 95% CI: 0.31–0.73, p=0.001) were strongly associated with long-term mortality.

Figure 1

Conclusions

Our study highlights outcomes in a long-term follow up of ICD patients and in light of the debate around the DANISH trial, we have shown that at 1 year, the benefit of ICD therapy is comparable in non-ischaemic compared to ischaemic cardiomyopathies. Moreover, patients who had an ICD implanted for secondary prevention had a 3-fold mortality benefit at 1 year and had a higher rate of death. Appropriate ICD therapy and a secondary prevention indication predicted long term mortality.

Design, modeling, and experimental validation of an acoustofluidic platform for nanoscale molecular synthesis and detection

Microfluidic technologies are increasingly implemented to replace manual methods in biological and biochemical sample processing. We explore the feasibility of an acoustofluidic trap for confinement of microparticle reaction substrates against continuously flowing reagents in chemical synthesis and detection applications. Computational models are used to predict the flow and ultrasonic standing wave fields within two longitudinal standing bulk acoustic wave (LSBAW) microchannels operated in the 0.5-2.0 MHz range. Glass (gLSBAW) and silicon (siLSBAW) pillar arrays comprise trapping structures that augment the local acoustic field, while openings between pillars evenly distribute the flow for uniform exposure of substrates to reagents. Frequency spectra (acoustic energy density E _ac vs frequency) and model-predicted pressure fields are used to identify longitudinal resonances with pressure minima in bands oriented perpendicular to the inflow direction. Polymeric and glass particles (10- and 20-µm diameter polystyrene beads, 6 µm hollow glass spheres, and 5 µm porous silica microparticles) are confined within acoustic traps operated at longitudinal first and second half-wavelength resonant frequencies (f _1,E = 575 kHz, gLSBAW; f _1,E = 666 kHz; and f _2,E = 1.278 MHz, siLSBAW) as reagents are introduced at 5-10 µl min^-1. Anisotropic silicon etched traps are found to improve augmentation of the acoustic pressure field without reducing the volumetric throughput. Finally, in-channel synthesis of a double-labeled antibody conjugate on ultrasound-confined porous silica microparticles demonstrates the feasibility of the LSBAW platform for synthesis and detection. The results provide a computational and experimental framework for continued advancement of the LSBAW platform for other synthetic processes and molecular detection applications.

Aβ1-42 increases the expression of neural KATP subunits Kir6.2/SUR1 via the NF-κB, p38 MAPK and PKC signal pathways in rat primary cholinergic neurons

ATP-sensitive potassium channels (KATP) may mediate a potential neuroprotective role in Alzheimer's disease (AD). Given that exposure to Aβ1-42 in cultured primary cholinergic neurons for 72 h significantly upregulates the expression of KATP subunits Kir6.2/SUR1, we aim to study the underlying signal transduction mechanisms that are involved in Aβ_1-42-induced upregulation of KATP subunits Kir6.2/SUR1. In the present study, we first identified the primary cultured rat cortical and hippocampal neurons using immunocytochemistry. 0.5 μM NF-κB inhibitor SN-50, 2 μM p38MAPK inhibitor SB203580 or 2 μM PKC inhibitor Chelerythrine chloride (CTC) were then added in three separate groups, followed by 2 μM Aβ_1-42 30 min later in all 3 groups. Western Blot was performed 72 h later to detect the expression of KATP subunits Kir6.2/SUR1. We found that Aβ_1-42 significantly increased the level of KATP subunits Kir6.2/SUR1 expression at 72 h when compared with the control group ( p < 0.05). However, when compared with the Aβ_1-42 group, the level of KATP subunits Kir6.2/SUR1 expression at 72 h significantly decreased in the SN50 + Aβ_1-42 group, SB203580 + Aβ_1-42 group, and the CTC + Aβ_1-42 group ( p < 0.05). Our findings suggest that the NF-κB, p38 MAPK, and PKC signal pathways are partially involved in the upregulation of KATP subunits Kir6.2/SUR1 expression induced by Aβ_1-42 cytotoxicity in neurons, which supports a potential theoretical basis of targeting these signal pathways in the treatment of AD.

Abstract P5-07-04: Not presented

This abstract was not presented at the conference.

Citation Format: Chatterjee S, Basak P, Tan S, Lefort S, Pellacani D, Safneck J, Buchel E, Aparicio S, Eaves CJ, Raouf A. Not presented [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-07-04.

Neurodevelopmental outcomes among extremely premature infants with linear growth restriction

OBJECTIVE

To compare neurodevelopmental outcomes in linear growth-restricted (LGR) infants born <29 weeks with and without weight gain out of proportion to linear growth.

STUDY DESIGN

We compared 2-year neurodevelopmental outcomes between infants with and without LGR and between LGR infants with and without weight gain out of proportion to linear growth. The outcomes were Bayley-III cognitive, motor, and language scores, cerebral palsy, Gross Motor Function Classification System (GMFCS) level ≥ 2, and neurodevelopmental impairment.

RESULT

In total, 1227 infants were analyzed. LGR infants were smaller and less mature at birth, had higher BMI, and had lower Bayley-III language scores (82.3 vs. 85.0, p < 0.05). Among infants with LGR, infants with high BMI had lower language scores compared with those with low-to-normal BMI (80.8 vs. 83.3, p < 0.05), and were more likely to have GMFCS level ≥2 and neurodevelopmental impairment.

CONCLUSION

Among infants with LGR, weight gain out of proportion to linear growth was associated with poorer neurodevelopmental outcomes.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

Detection of novel mutations associated with independent resistance and cross-resistance to isoniazid and prothionamide in Mycobacterium tuberculosis clinical isolates

OBJECTIVES

Prothionamide, a structural analogue of isoniazid, is used mainly for treating multidrug-resistant tuberculosis (MDR-TB). Both drugs have a common target InhA, so prothionamide can be ineffective against isoniazid-resistant (INH^R) Mycobacterium tuberculosis. We aimed to investigate the prevalence of mutations in katG, ethA, ndh, ethR, mshA, inhA and/or its promoter associated with independent resistance and cross-resistance to INH^R and/or prothionamide-resistant (PTO^R) M. tuberculosis isolates.

METHODS

We sequenced the above genes in 206 M. tuberculosis isolates with susceptibility testing against ten drugs.

RESULTS

Of the 173 INH^R PTO^R isolates, 170 (98.3%) harboured mutations in katG, 111 (64.2%) in ethA, 58 (33.5%) in inhA or its promoter, 5 (2.9%) in ndh, 3 (1.7 %) in ethR and 2 (1.2%) in mshA. Among the 18 INH^R PTO^S isolates, mutations in katG were found in all of them; one had a mutation in the inhA promoter and another in ndh. Of the five INH^S PTO^R isolates, four showed mutations in ethA and two in the inhA promoter. Notably, 55 novel non-synonymous mutations were found in them and 20.2% of the PTO^RM. tuberculosis isolates harboured no known mutations.

CONCLUSIONS

This is the first report to investigate cross-resistance between INH^R and/or PTO^R isolates. Among INH^R (94.4% MDR-TB) M. tuberculosis isolates, the high diversity of mutations for independent resistance and cross-resistance with prothionamide highlight the importance of both phenotypic susceptibility and genotypic diagnosis when using it to treat patients with INH^R-TB. The high proportion (one-fifth) of PTO^RM. tuberculosis isolates showed no known mutation related to PTO^R genes, so uncovered resistance mechanism(s) of prothionamide exist.

Enhanced energy gain in a dielectric laser accelerator using a tilted pulse front laser

Using an 800 nm, 45 fs pulse-front-tilted laser we demonstrate a record 315 keV energy gain in a dual grating dielectric laser accelerator (DLA) and average accelerating gradients of 560 MV/m over 0.5 mm. These results open a new regime in DLA characterized by significant evolution of the beam distribution in the longitudinal phase space, corresponding to > 1/4 of a synchrotron oscillation. By tilting the laser wavefront we control the resonant velocity of the DLA and observe a net energy gain, indicating that a tapered optical phase could be used to achieve very high energy gain.