Chord length sampling with memory effects for spatially heterogeneous Markov media: Application to the rod model

In this work we propose a modified Chord Length Sampling (CLS) algorithm, endowed with two layers of "memory effects," aimed at solving particle transport problems in one-dimensional spatially nonhomogeneous Markov media. CLS algorithms are a family of Monte Carlo methods which account for the stochastic nature of the media by sampling on-the-fly the random interfaces between material phases during the particle propagation. The possibility for the particles to remember the last crossed interfaces increases the accuracy of these models with respect to reference solutions obtained by solving the Boltzmann equation on a large number of realizations of the Markov media. In previous investigations, CLS models with memory have been tested exclusively for spatially uniform stochastic media: in this paper we extend this class of Monte Carlo methods to the case of spatially nonhomogeneous configurations. The effectiveness and the robustness of the modified CLS are probed considering several benchmark problems with varying material cross sections and Markov media densities. The obtained results are a stepping stone towards a generalization to three-dimensional models.

Potential impact of a new generation of remote monitoring platform: evaluation of the yearly triage burden for 35 595 patients

Background

Remote monitoring (RM) has become a new standard of care in the follow-up of patients with cardiac implantable electronic devices (CIEDs). It increases the probability of survival, reduces hospitalizations and health care costs, improves clinical outcome, prevents atrial fibrillation-related strokes and increases patient acceptance and satisfaction. However, human review of the all CIEDs generated data is tedious and time-consuming for healthcare professionals.

Purpose

This study intends to determine the RM alert burden in a European multicentric cohort of patients with a CIED and the impact that a multivendor platform could have on the remote management of patients.

Method

This retrospective study was conducted on all patients with a CIED remotely followed-up via a universal platform between 01/01/2020 and 12/31/2020 across 71 centers. We measured the quantity, frequency and criticality of patients' transmissions, and related episodes and alerts for all types of devices. Scheduled and triggered transmissions were included, but daily transmissions of data without alerts (such as Biotronik) were excluded as they are usually not reviewed by medical teams.

Results

A total of 35 595 patients were analyzed: 12 065 (34%) implantable cardioverter-defibrillator (ICD), 8 705 (24%) cardiac resynchronization therapy defibrillator (CRT-D), 8 341 (23%) implantable pulse generator (IPG), 1 248 (4%) cardiac resynchronization therapy pacemaker (CRT-P), 1 891 (5%) subcutaneous implantable cardioverter-defibrillator (S-ICD), and 3 345 (10%) implantable loop recorder (ILR). A total of 504 580 transmissions were received, with an average of 14.2 /patient (p)/year (y). 81% of the transmissions were scheduled, 16% patient-initiated and 3% device initiated.

A total of 1 521 653 episodes were received (41.5/p/y) with CRT-D (63/p/y) and ILR (54.6 y/p/y) generating most of the episodes. Most common episodes for CRT-D is AT (atrial tachycardia)/AF atrial-fibrillation) (51%), whereas AT/AF (39.1%) and Pause (50.4%) are most common for ILR.

A total number of 814 777 alerts were triggered (22.9 /p/y). ILR had 273% more alerts (85.5/p/y) while S-ICD (12/p/y), IPG (13.1/p/y) and ICD (13.6/p/y) had less. 3.5% were set as red alerts, 32.3% yellow alerts, 7.5% blue alerts. 56.7% were set to “off” by the medical teams on the proprietary platform by using the notification settings, allowing for a universal custom filtering of alerts. A total number of 28 284 red alerts were triggered (0.8 / p/y), mostly by CRT-D (1.4/p/y) and ILR (1.3/p/y).

Conclusion

A high number of transmissions, episodes and alerts are still generated by RM in 2020 with routine care settings, as measured with a new RM universal platform. Routine customizing settings across vendors allowed medical teams to reduce the total number of reviewed alerts by 57%. Algorithms identifying significant AF alerts, or readjudicating episodes from ICD and ILR could be important to further reduce the RM burden.

Funding Acknowledgement

Type of funding sources: None. Number of episodes per patient per yearAlerts by priority

Most remote monitoring alerts about atrial fibrillation are not relevant to identify clinically significant events: proposal of a new approach

Background

Cardiac Implantable Electronic Devices (CIEDs) are an important tool for detecting Atrial Fibrillation (AF) in implanted patients.

However AF burden values and notifications emitted by the manufacturer's platforms are not directly related to the standard classification of AF types (paroxysmal, persistent or permanent) that are used in daily practice. Moreover, AF alerts represent the most frequent notifications for implanted patients resulting in a time-consuming review for healthcare professionals.

Purpose

This study intends to compare the manufacturers' atrial burden related notifications in remotely monitored (RM) patients to the detection of clinically significant events with a new proprietary algorithm.

Methods

From 2017 to 2020, all RM patients from 57 centers with daily atrial burden measurements available for at least 30 days and at least one atrial burden related alert were enrolled.

All atrial burden related alerts emitted by the manufacturers' platforms were compared to the following clinically significant events (based on the standard classification) detected by a new proprietary algorithm: “1st recorded AT/AF episode”, “paroxysmal AF”, “increasing paroxysmal AF”, “persistent AF”, and “end of persistent AF”.

Results

This multicentric retrospective study analyzed, between 01/2017 and 10/2020, 2 463 RM patients with a Biotronik, Boston Scientific or Medtronic CIED (implantable defibrillator, pacemaker or implantable loop recorder), with a mean follow-up of 490 days [33–1386].

A total of 22 345 manufacturers' atrial burden related alerts were emitted while only 4 826 clinically significant events were detected by the algorithm: 1770 “1st recorded AT/AF episode”, 620 “Paroxysmal AF”, 252 “Increasing paroxysmal AF”, 1373 “Persistent AF”, and 811 “End of persistent AF”.

These clinically significant events represent only 22% of the total number of atrial burden related alerts emitted by the manufacturers' platforms.

Conclusion

A new AF alert algorithm could have the potential to identify clinically significant AF status change in remotely monitored implanted patients while reducing the total number of alerts generated and thus the review burden for healthcare professionals.

Funding Acknowledgement

Type of funding sources: None.

[The use of administrative health databases in infectious disease epidemiology and public health]

BACKGROUND

The public health burden resulting from infectious diseases requires efforts in surveillance and evaluation of health care. The use of administrative health databases (AHD) and in particular the French national health insurance database (SNIIRAM) is an opportunity to improve knowledge in this field. The SNIIRAM data network (REDSIAM) workshop dedicated to infectious diseases conducted a narrative literature review of studies using French AHD. From the results, benefits and limits of these new tools in the field of infectious diseases are presented.

METHODS

Publications identified by the members of the workgroup were collected using an analytical framework that documented the pathology of interest, the aim of the study, the goal of the developed algorithm, the kind of data, the study period, and the presence of an evaluation or a discussion of the performance of the performed algorithm.

RESULTS

Fifty-five articles were identified. A majority focused on the field of vaccination coverage and joint infections. Excluding vaccine coverage field, the aim of 28 studies was epidemiological surveillance. Twenty-six studies used hospital databases exclusively, 18 used ambulatory databases exclusively and 4 used both. Validation or discussion of the performed algorithm was present in 18 studies.

CONCLUSIONS

The literature review confirmed the interest of the French AHD in the infectious diseases field. The AHD are additional tools of the existing surveillance systems and their use will probably be more frequent in the coming years given their advantage and reliability. However, incoming users need to be assisted. Thus, the workgroup will contribute to a reasonable use of AHD and support future developments.

Surface properties of amphiphilic carbon nanotubes and study of their applicability as basic catalysts

Amphiphilic hybrid carbon nanotubes (CNTs) containing a hydrophobic undoped section connected to a hydrophilic N-doped segment were synthesized. Their application as basic catalysts in the aldol condensation of furfural and acetone was tested.

Ultra low κ PECVD Porogen Approach: Matrix Precursors Comparison and Porogen Removal Treatment Study

The introduction of new dielectrics into silicon chip interconnection technology is necessary to increase electrical performance. Sub-65nm technologies need κ values below 2.5 and the main way to reduce the dielectric constant is to introduce porosity. This work reports results concerning a two steps PECVD porogen approach to perform Ultra Low κ (κ <2.5). The first step is an hybrid material deposition: i.e. an a-SiOC:H matrix containing organic sacrificial inclusions (porogen phase). In the second step, the porogen is removed by a suitable curing to generate porosity. Two siloxane precursors (decamethylcyclopentasiloxane and diethoxymethylsilane) were evaluated as matrix precursors. Their influences, as well as O2 addition in plasma gas feed, in terms of cross-linking and incorporation were evaluated by FTIR analysis. Thermal anneal and UV treatment (thermally assisted) were evaluated as a curing second step. It allows to better understand this critical step which combines porogen removal and material cross-linking. By optimizing deposition and curing parameters, κ value lower than 2.4 were obtained.

A first-in-human phase I trial of PBI-05204 (oleandrin), an inhibitor of Akt, FGF-2, NF-Kb, and p70S6K in advanced solid tumor patients

3537

Background: PBI-05204 contains oleandrin, a cardiac glycoside, which inhibits the α-3 subunit Na-K ATPase pump. Over-expression of the α-3 subunit in malignant cells correlates with the tumor proliferation. Oleandrin inhibits FGF- 2 export and activation of NF-Kβ and inhibits phosphorylation of Akt. PBI-05204 also inhibits p70S6K, decreasing mTOR activity. In this ongoing study of PBI-05204, we sought to determine the DLTs, MTD and recommended phase II dose in advanced solid tumors patients (pts) and to characterize its’ pharmacokinetics (PK) and pharmacodynamics (PD). Methods: This was a standard 3+3 phase I design. PBI-05240 was given orally for 21 days of 28 days. Dose was increased by 100% if no related grade 2 adverse event (AE) was observed and increased by 50% if a grade 2 AE occurred. If no other grade 2 AE were observed then subsequent dose escalation was resumed at 100%. In order to determine drug-mediated changes in pAkt, p70S6K, and S6 (mTOR effectors) expression as a surrogate marker of target effect, peripheral blood mononuclear cells (PBMCs) were obtained in addition to PKs. Results: To date 15 pts have received PBI-05204 at 5 dose levels (0.6 mg to 10.2 mg/day), 2 pts are currently active at dose level 5. No DLT has been observed thus far. 10 out of 15 pts (67%) experienced only grade 1 AEs, most common: fatigue and constipation (20%). No significant cardiac toxicities have been observed, only first degree AV block and grade 2 PVC's. Of the 15 evaluable pts, 3 had stable disease for > 4 months, with bladder, colorectal, and fallopian tube cancer pts having an 11, 16, and 10% reduction by RECIST respectively. PKs initially show dose-dependent peak plasma oleandrin concentrations are reached at 2–4 hr following administration with > 50% cleared in 6 hrs. Western blots of PBMCs showed PBI-05204 markedly reduced phosphorylation of Akt, p70S6K, and S6 in a time dependent manner in 4 pts (1 at dose level 2, and 3 and 2 at dose level 5). Reduction of these effectors was observed concomitantly with relatively higher levels of Na, K-ATPase α-3 subunit expression. Conclusions: PBI-05204 is tolerated up to 10.2/mg/day with very little AE's or cardiotoxicity. Initial response evaluation shows activity in diverse tumors with PD analysis suggesting target effect.

[Table: see text]

Postnatal electrical and morphological abnormalities in lumbar motoneurons from transgenic mouse models of amyotrophic lateral sclerosis

Antidromically identified lumbar motoneurons intracellularly recorded in the entire brainstem/spinal cord preparation isolated from SOD1(G85R) postnatal mice (P3-P10) were labelled with neurobiotin and fully reconstructed in 3D from serial sections in order to analyse their morphology. This staining procedure revealed differences between WT and SOD1(G85R) dendritic trees for most metric and topologic parameters analyzed. A highly complex morphology of SOD1(G85R) motoneurons dendrites (increased number of branching points and terminations) was found and the dendritic trees were longer compared to the WT motoneurons. These morphological changes observed in P8-P9 motoneurons mice occurred concomitantly with a decrease in the input resistance and gain. During electrophysiological recordings, four patterns of discharge were observed in response to ramp stimulations, that were equally distributed in WT and SOD1(G85R) motoneurons. In slice preparation, whole cell patch-clamp recordings made from developing motoneurons in SOD1(G85R) and double transgenic SOD1(G93A)/Hb9-eGFP mice showed that Riluzole, a blocker of persistent inward sodium conductance, altered the repetitive firing in a similar way for the 2 strains. These results show that the SOD1 mutations linked to familial ALS alter the development of the electrical and morphological properties of lumbar motoneurons.

Significance of stress myocardial perfusion scans in predicting cardiovascular events and mortality in cancer patients

17009

Background: Cardiac risk assessment in cancer patients has not extensively been studied. We evaluated the role of stress myocardial perfusion scan (SMPS) in predicting cardiovascular outcomes in cancer patients. Methods: A retrospective chart review was performed on 787 patients who had a SMPS from 01/2002 - 03/2003. All patients were followed for at least 1.5 years. Cox proportional hazard model was used to determine the time-to-first event [cardiac death, myocardial infarction (MI) and coronary revascularization]. Cardiac death was defined as documented cardiac death or sudden unexplained death. Results: A total of 501/787 (64%) patients had normal SMPS, whereas 286/787 (36%) had abnormal SMPS. Adenosine [430/787 (55%)] and dobutamine [144/787 (14%)] were used for chemical stress while 213/787 (23%) patients underwent exercise testing. Mean age was 66±11 years and median follow-up duration was 1.8 years. The 3- year event-free survival rate was 0.71 (0.64–0.78) for abnormal SMPS and 0.87 (0.8–0.94) for normal SMPS (p<0.0001). Of all abnormal scans (n=286), 3-year event free-survival rate based on type of vascular defects varied from 0.79(0.67–0.93) for fixed defects, 0.68 (0.58-.08) for reversible defects and 0.63 (0.5–0.8) for co-existent fixed and reversible defects (p<0.0001). Other factors adversely affecting event-free survival were male gender (p=0.025), cardiomyopathy (p=0.001), coronary artery disease (p<0.0001), previous MI (p<0.0001), congestive heart failure (p=0.001) and hypercholesterolemia (p<0.0001). When we analyzed cardiac death as a separate event, SMPS results still made a significant difference with 3-year cardiac-survival rate of 0.79 (0.69–0.91) for abnormal scan group versus 0.88 (0.81–0.95) for normal scan group (p=0.05). Furthermore, the 3-year cardiac-survival rate in patients with both fixed and reversible defects was 0.4 (0.1–1), which was much worse than those with fixed [0.87 (0.76–0.99)] or reversible [0.85 (0.74–0.99)] defects alone (p=0.028). Conclusions: SMPS is a highly useful modality for predicting cardiac events and mortality in cancer patients. The characteristics of the perfusion defect further stratifies the patients at higher risk.

No significant financial relationships to disclose.