Severe sleep apnea is associated with atrial fibrillation burden in pacemaker recipients

Background

New generation pacemaker allow the assessment day by day of sleep disordered breathing (SDB) based on impedance measurement. A recent study demonstrated that incidence of AF is higher in case of severe SA monitored by pacemaker

Purpose

The aim was to compare the atrial fibrillation (AF) burden between patients with severe and non-severe sleep apnea (SA) detected with pacemakers monitoring (SDB).

Methods

This retrospective study was carried out at our University Hospital. We included all patients with Microport CRM pacemaker implanted from 2013 to 2016 at our university hospital. Exclusion criteria were inactivation of sleep apnea monitoring (SAM), history of sleep apnea, missing data or invalid data. AF burden was assessed according to Fallback mode switch (FMS) duration. Respiratory disturbance index (RDI) was calculated as the average number of events (ventilation pause and reductions) per number of hours of monitoring. Patients with RDI<20/h were compared with patients with RDI≥20/h (considered as severe SA group).

Results

404 patients (mean age = 79.7±10 years; 52.0% men) were included. The most prevalent indication for cardiac pacing was atrioventricular block in 57%. Mean RDI was 18.9 events per hour. 234 (58%) of them had a mean RDI <20 and 170 (42%) had a mean RDI ≥20. Compared to patients with mean RDI<20, those with mean RDI ≥20 were youngers (78.6±10 years Vs 81.8±8 years; p=0.02), were more likely to be male (58.2% Vs 47.5%: p=0.035) and had more heart failure history (28.8% Vs 19.2%: p=0.03). BMI was not different between groups (26.3±5. vs 26.3±4; P=0.33). Mean follow-up was 27 months. Patients with RDI ≥20 had a mean Atrial fibrillation duration longer than patients with RDI <20 (631 min Vs 291 min respectively; p=0.014). RDI was correlated with FMS (r=0.26; p=0.0004). The stroke rate tended to be higher in the RDI ≥20 group (2.1% vs 5.4%) (p=0.12).

Conclusion

Severe SA detected by pacemaker was associated with longer AF duration. We did not find higher occurrence of stroke in the severe SA group.

Funding Acknowledgement

Type of funding source: None

Efficacy of deep sedation for patients with intractable electrical storm refractory to anti-arrhythmic drugs

Background

Sympathetic overactivity is implicated in the initiation and maintenance of electrical storm (ES). Deep sedation has empirically been considered as an efficient therapeutic option to blunt sympathetic tone and control ES.

Purpose

The aim of this multicenter study was to determine the efficacy of deep sedation in patients presenting intractable ES refractory to anti-arrhythmic drugs.

Methods

Patients requiring deep sedation for refractory ES from January 1st 2007 to July 31st 2018 were retrospectively included in 13 centers. The primary endpoint was the rate of acute response to sedation, defined as ES termination within 15 minutes after deep sedation.

Results

Among the 116 patients, 55 (47.4%) had ES termination within 15 minutes and were considered “acute responders” to deep sedation. Clinical signs of congestive heart failure before deep sedation (OR=3.31, 95% CI:1.001–10.97, p=0.049) was the only independent predictor of non-acute response. Twenty-one non-acute responders (34.4%) had an extracorporeal membrane oxygenation (ECMO) implanted. Non-acute responders had a significantly lower in-hospital survival (Log-rank, p=0.010). ECMO implantation did not influence survival in non-acute responders to sedation. Acute response to deep sedation was an independent protector of in-hospital mortality, decreasing by 73% the risk of death (OR 0.27; 95% CI:0.10–0.70, p=0.008).

Conclusion

To the best of our knowledge, this multicenter study is the first analysis of the efficacy of deep sedation in patients with intractable ES refractory to anti-arrhythmic drugs, and demonstrating the positive impact of “acute response” on in-hospital survival.

Funding Acknowledgement

Type of funding source: None

Pacemakers capable of monitoring sleep-disordered breathing: impact on sleep apnea detection in real life

Background

Pacemaker recipients are at high-risk of sleep apnea (SA). New generation of pacemakers allow day by day, sleep-disordered breathing (SDB) monitoring. These devices measure variations in thoracic impedance and can detect apnea and hypopnea.

Purpose

The aim was To compare the rate of SA detection in patients implanted with and without pacemaker capable of monitoring (SDB).

Methods

This retrospective study included all consecutive patients implanted with a pacemaker between 2013 and 2016 at Poitiers university hospital. Pacemaker recipients allowing SDB monitoring (SDB monitoring group) and pacemaker recipients not allowing SDB monitoring (control group) were compared in terms of SA diagnosis, continuous positive airway pressure (CPAP) therapy initiation, newly AF discovered and stroke occurrence.

Results

Among the 1442 patients included (mean age 79 years, 39% of women, BMI = 27 kg/m2). 653 were in the SDB monitoring group and 789 in the control group. The 2 groups were not different in terms of age, body mass index, cardiovascular risk factor, cardiac function, and medication. Indication for cardiac pacing was atrioventricular block and sinus dysfunction in 56% and 23% of patients respectively. Mean follow-up was 24.7 months. 40 patients (7.5%) have been diagnosed with SA in the SDB monitoring group and 18 (2.7%) in the control group (p<0.001). CPAP therapy was initiated in 33 (5%) patients in SDB monitoring group and in 16 (2%) patients for the control group (p=0.01). The rate of newly diagnosed AF was 15% in SDB monitoring and 7% in control group (p<0.001). The incidence of stroke was 16 (2.4%) in the SDB monitoring group and 18 (3.4%) in the control group (P=0.45).

Conclusion

In real life conditions, pacemakers capable of monitoring SDB improve the diagnosis of SA and CPAP therapy rate.

Monitoring of sleep apnea after at least

Funding Acknowledgement

Type of funding source: None

PET and MRI guided adaptive radiotherapy: Rational, feasibility and benefit

Adaptive radiotherapy (ART) corresponds to various replanning strategies aiming to correct for anatomical variations occurring during the course of radiotherapy. The goal of the article was to report the rational, feasibility and benefit of using PET and/or MRI to guide this ART strategy in various tumor localizations. The anatomical modifications defined by scanner taking into account tumour mobility and volume variation are not always sufficient to optimise treatment. The contribution of functional imaging by PET or the precision of soft tissue by MRI makes it possible to consider optimized ART. Today, the most important data for both PET and MRI are for lung, head and neck, cervical and prostate cancers. PET and MRI guided ART appears feasible and safe, however in a very limited clinical experience. Phase I/II studies should be therefore performed, before proposing cost-effectiveness comparisons in randomized trials and before using the approach in routine practice.

Quantitative phase-mode electrostatic force microscopy on silicon oxide nanostructures

Phase-mode electrostatic force microscopy (EFM-Phase) is a viable technique to image surface electrostatic potential of silicon oxide stripes fabricated by oxidation scanning probe lithography, exhibiting an inhomogeneous distribution of localized charges trapped within the stripes during the electrochemical reaction. We show here that these nanopatterns are useful benchmark samples for assessing the spatial/voltage resolution of EFM-phase. To quantitatively extract the relevant observables, we developed and applied an analytical model of the electrostatic interactions in which the tip and the surface are modelled in a prolate spheroidal coordinates system, fitting accurately experimental data. A lateral resolution of ∼60 nm, which is comparable to the lateral resolution of EFM experiments reported in the literature, and a charge resolution of ∼20 electrons are achieved. This electrostatic analysis evidences the presence of a bimodal population of trapped charges in the nanopatterned stripes.

P1449Anti-thrombotic management for electrophysiological procedures: results of the European Heart Rhythm Association (EHRA) young investigators survey

Funding Acknowledgements

none

Background

Electrophysiological studies (EPS), with or without ablation, require percutaneous introduction of catheters into the heart to record local electrical activity. Instrumentation of catheters within the blood causes activation of the clotting cascade, increasing the risk of thrombus formation. To date, the electrophysiological community lacks international guidelines on the use of anti-thrombotic therapies before, during and after EPS.

Purpose

To survey the current practice regarding the use of anti-thrombotic therapies across member countries of the European Heart Rhythm Association (EHRA).

Methods

The survey was conducted in February 2019. Electrophysiologists from EHRA member countries were contacted to complete the survey by e-mail, utilizing the EHRA Young EP network. They were asked to answer a questionnaire containing information on anti-thrombotic and anticoagulation management before, during and after left-sided EPS and ablation: atrial tachycardia (AT), accessory pathway (AP) and ventricular tachycardia (VT).

Results

We obtained 41 answers responses from 40 centers in 15 European EHRA member countries. Regarding of antiaggregation, the most used antiplatelet is aspirin (100% before, during and after ablation). The most used anticoagulant was novel oral anticoagulants (NOAC) before ablation (47.1%), during hospitalization (85.2%) and at discharge (70.3%). The administration of anti-thrombotic therapy depended on the procedure time only in 10 cases (24.4%).

For AP, before ablation, only 4 centers (9.7%) administered anti-platelets and 2 (4.9%) anticoagulants. During ablation, heparin was used by 85.4% of respondents maintaining ACT target 300-350 s in 36.6% of cases. At discharge, antiaggregation therapy was prescribed by 22 colleagues (53.7%) and anticoagulation only by one (2.4%).

In patients with AT, before ablation, antiaggregation prophylaxis was prescribed by only 4 centers (19.5%) and anticoagulation by 11 (26.8%). During procedure, almost all centers (40, 97.6%) used heparin with ACT target 300-350 s in 58.5% of cases. At discharge, antiplatelet therapy was recommended by 12 colleagues (29.3%) and anticoagulation by 24 (58.5%).

Regarding VT, before procedure, 8 centers (19.5%) prescribed antiaggregation and 5 (12.2%) anticoagulation prophylaxis. During ablation, all centers used heparin, maintaining ACT target 300-350 s in 58% of cases. The use of antiaggregation or anticoagulation depended on the left ventricle (LV) access in 15 centers (37.5%) and on LV ejection fraction in 11 (26.8%). At discharge, anti-thrombotic therapy was recommended by 16 colleagues (39%) and anticoagulation by 13 (31.7%).

Conclusion

Our survey showed that there is considerable variation in the management of anti-thrombotic therapy surrounding left-sided EPS and ablation. Further studies are necessary to evaluate the right approach to these procedures.

THU0053 CONTRIBUTION OF DEFECTIVE NON-APOPTOTIC FAS SIGNALING TO IMMUNE DYSREGULATION IN AUTOIMMUNE LYMPHOPROLIFERATIVE SYNDROME (ALPS)

Background:

ALPS patients show impaired generation of humoral memory for T independent antigens whereas they generate memory for self-antigens due to impaired FAS-dependent removal of autoreactive germinal center B cells. It is known that FAS signaling via caspase activation results in cell apoptosis. However, FAS ligation may also initiate or modulate non-apoptotic signaling as shown for example by its ability to activate NF-κB. Recent data implicate a regulatory role of FAS in the modulation of mTOR signaling in ALPS double-negative T cells. Moreover, a recently described C194V FAS mutation disturbs its post-translational modification leading to impaired apoptosis induction while non-apoptotic signalling is still intact. Consequently, C194V FAS protects from the autoimmune phenotype in the murine ALPS system. This supports the view that FAS may prevent autoimmunity with other mechanisms than inducing apoptosis.

Objectives:

We hypothesize that FAS mutations impair this modulatory signaling, leading to hyper-activation of B cells. Therefore we aim to investigate non apoptotic FAS signaling in B cells derived from healthy individuals and ALPS patients.

Methods:

We studied resting and activated B cells in ALPS patients in presence or absence of FAS ligand by flow cytometry analysing relevant molecules to the CD40 signaling pathway. We used mass cytometry to perform functional phenotyping of B cells isolated from secondary lymphoid organs. Proteomic studies were performed to identify potential signaling circuits and RNA sequencing to study the consequences of FAS signaling on B cell fate.

Results:

In CD40L activated B cells, FAS signaling results in specific modulation of the mTOR signaling pathway. This modulation is absent in ALPS derived B cells. In line with these data germinal center B cells and plasmablast from secondary lymphoid organs of ALPS patients show hyperactive mTOR signaling pathway. Proteomic studies identify a circuit that links FAS to the phosphatase PTEN via DAXX and the deubiquitinase USP7.

Conclusion:

We describe a new role of FAS in the regulation of B cell activation. Defects in FAS signaling in ALPS contribute to dysregulation of the mTOR signaling pathway and disturbed B cell development.

Disclosure of Interests:

None declared

Technical Note: Flattening filter free beam from Halcyon linac: Evaluation of the profile parameters for quality assurance

INTRODUCTION

The use of flattening filter free (FFF) beams generated by standard linear accelerators is increasing in the clinical practice. The radiation intensity peaked toward the beam central axis is properly managed in the optimization process of treatment planning through intensity modulation. Specific FFF parameters for profile analysis, as unflatness and slope for FFF beams, based on the renormalization factor concept has been introduced for quality assurance purposes. Recently, Halcyon, an O-ring based linear accelerator equipped with a 6 MV FFF beam only has been introduced by Varian.

METHODS

Renormalization factors and related fit parameters according to Fogliata et al. ["Definition of parameters for quality assurance of FFF photon beams in radiation therapy," Med. Phys. 39, 6455-6464 (2012)] have been evaluated for the 6 MV FFF beam generated by Halcyon units. The Halcyon representative beam data provided by Varian were used. Dose fall-off at the field edges was matched with an unflattened beam generated by a 6 MV from a TrueBeam linac. Consistency of the results was evaluated against measurements on a clinical Halcyon unit, as well as a TrueBeam 6 MV FFF for comparison.

RESULTS

The five parameters in the analytical equation for estimating the renormalization factor were determined with an R² of 0.997. The comparison of the unflatness parameters between the Halcyon representative and hospital beam data was consistent within a range of 0.6%. Consistently with the computed parameters, the Halcyon profiles resulted in a less pronounced peak than TrueBeam.

CONCLUSION

Renormalization factors and related fit parameters from the 6 MV FFF beam generated by the Varian Halcyon unit are provided.

Using consistent terms in precision medicine to eliminate patient confusion

e24164

Background: Biomarker testing has advanced precision medicine in cancer. However, not all eligible patients benefit from biomarker-driven therapies due to suboptimal testing rates. A working group of 20 patient advocacy groups representing solid/hematologic malignancies, three professional societies, and 18 pharmaceutical and diagnostics companies identified patient confusion inconsistent testing terms as a possible contributing factor to biomarker testing underutilization. The group aimed to address patients’ confusion by identifying and adopting consistent, plain language terms for biomarker and germline genetic testing that are applicable across cancer types. Methods: Following a stakeholder roundtable discussion on barriers to precision medicine, working group members participated in interviews on their goals for consistent testing terminology for their constituents. We then conducted a framework analysis covering five themes: available testing by cancer type; purpose of test; biospecimen source; terms used in patient education; and preferred plain language term. Working group members were surveyed on preferences for germline testing terminology and also deployed a preliminary patient survey to their constituents to gain insight on preferences for germline testing terms. Results: Interviews, framework analysis, and surveys revealed notable differences across cancer communities. We identified at least 33 different terms related to biomarker, genetic and genomic testing being used in patient education and clinical care among the different cancer communities and stakeholders. Terminology was complicated by the variety of testing modalities and gene mutations tested for across cancers. Following multiple discussions, working group members agreed on two umbrella terms to distinguish between somatic and germline testing with additional context for specific cancer communities. “Biomarker testing” was selected as the somatic testing term. “Genetic testing for an inherited mutation” and “genetic testing for inherited cancer risk” were selected as preferred germline testing terms. Conclusions: Our findings highlight the disparate testing terminology landscape and the need for consistent terms to reduce patient confusion, improve communication, facilitate shared decision-making and assure concordance in policy development.

P1899Heparin and low-molecular-weight heparin switch associated with an increase in bleeding complications in patients on apixaban undergoing catheter ablation: The AMPER ABLATION study

Background

The aim of this study was to identify the factors associated with bleeding complications in patients taking apixaban and undergoing a catheter ablation in everyday clinical practice.

Methods

AMPER ABLATION is a multicenter, observational, prospective study of patients with non valvular atrial fibrillation (AF) undergoing a catheter ablation. Eligible patients had been taking apixaban (2.5 or 5 mg twice daily) for ≥3 weeks before the procedure, and were followed for 30 days afterwards.

Results

A total of 595 patients (65 [interquartile range 59, 72] years, 67% male, mean CHA2DS2-VASc score 1.85±1.37) were enrolled at 25 academic/nonacademic centers in France; 524 patients (88%) were receiving apixaban 10 mg/day and 71 (12%) 5 mg/day. 323 patients (54%) underwent an AF ablation, and 272 (46%) an atrial flutter (AFL) ablation. The most prevalent concomitant disorders were hypertension (51% of patients), diabetes (15%) and vascular disease (10%). Mean creatinine concentration was 1.06±0.28 mg/dL, median weight was 83±18 kg and mean creatinine clearance (Cockcroft-Gault) was 82±34 mL/min. The management of apixaban in the periprocedural period was left to the investigator's preference. Overall, 264 patients were switched to unfractionated heparin or enoxaparin (238 for AF ablations and 26 for AFL ablations). The median duration of switch was 29 hours. Complications were reported at 30 days, and included 12 bleeding events (1 tamponade needing drainage, 1 pericardial effusion without drainage, 7 International Society on Thrombosis and Haemostasis [ISTH] non major bleedings for AF ablations and 1 pericardial effusion without drainage, and 2 ISTH non major bleedings for AFL ablations) and 1 embolic event (non disabling stroke for an AF ablation). Comparing patients with and without a bleeding event revealed a higher rate of heparin or low-molecular-weight heparin (LMWH) switching in patients with a bleeding event (60% vs 35%; p=0.02). A switch to heparin or LMWH was the only factor associated with an increase rate of bleeding (odds ratio 2.5; [CI 95%; 1.1, 7.1]; p=0.01).

Conclusion

Heparin or LMWH switch in the periprocedural AF and AFL-ablation period is associated with an increased rate of bleeding complications at 30 days.

Acknowledgement/Funding

Financial support from BMS

2404The use of wearable cardioverter defibrillator in France

Background

The wearable cardioverter defibrillator (WCD) has been shown to be useful during transient periods of high sudden cardiac death risk, and the issue of compliance recently pointed out. This Registry was designed to provide real-world data on WCD use in France, in terms of compliance, potential adverse events, as well as efficacy.

Methods and results

Multicenter evaluation (WEARIT FRANCE Registry) was conducted in France between January 2017 and March 2018. Overall, 1,157 patients were analyzed: 950 with ischemic heart disease (82%, including 647 patients after myocardial infarction), 119 after ICD explant (10%), and 88 pre-transplant (8%). The median age was 61 years; the median ejection fraction was 25%. Median WCD wear time was 62 days, with median daily use of 23.4 hours. Less than 1% of patients did not wear WCD at least 4 hours per day. During follow-up, a total of 42 sustained ventricular tachyarrhythmias (VT/VF) occurred in 36 patients, of whom 50% (n=18) received appropriate WCD shocks, giving an incidence of appropriate therapy of 1.56%. The rate of all VT/VF episodes were 3.1% among patients with ischemic cardiomyopathy (n=29/950) versus 3.4% for the others (n=7/207). Of the ischemic patients wearing beyond 30 days (N=784), 5 received appropriate therapy of VT/VF episodes. Overall shock survival was 100%. At the end of the WCD period, 586 patients (51%) were implanted with an implantable cardioverter defibrillator. Eight patients (0.69%) received inappropriate WCD shocks. Regarding the apparent very low proportion of women considered for WCD therapy, we aimed to appreciate in which extent

Conclusions

In this multicenter nationwide WCD evaluation, 3.1% of patients presented with sustained VT/VF with 47% of those patients developing VT/VF after 30 days. The incidence of inappropriate therapy was low. The compliance to WCD in this real life evaluation was very high. These data suggest that the WCD, when worn appropriately, may be helpful in the arsenal to protect high-risk patients against SCD, especially in case of transient risk situations.

Acknowledgement/Funding

Zoll