Confronting system barriers for ST- elevation MI in low and middle income countries with a focus on India

© 2017 Our previous research found seven specific factors that cause system delays in ST-elevation Myocardial infarction management in developing countries. These delays, in conjunction with a lack of organized STEMI systems of care, result in inefficient processes to treat AMI in developing countries. In our present opinion paper, we have specifically explored the three most pertinent causes that afflict the seven specific factors responsible for system delays. In doing so, we incorporated a unique strategy of global STEMI expertise. With this methodology, the recommendations were provided by expert Indian cardiologist and final guidelines were drafted after comprehensive discussions by the entire group of submitting authors. We expect these recommendations to be utilitarian in improving STEMI care in developing countries

Motoneuron membrane potentials follow a time inhomogeneous jump diffusion process

Stochastic leaky integrate-and-fire models are popular due to their simplicity and statistical tractability. They have been widely applied to gain understanding of the underlying mechanisms for spike timing in neurons, and have served as building blocks for more elaborate models. Especially the Ornstein–Uhlenbeck process is popular to describe the stochastic fluctuations in the membrane potential of a neuron, but also other models like the square-root model or models with a non-linear drift are sometimes applied. Data that can be described by such models have to be stationary and thus, the simple models can only be applied over short time windows. However, experimental data show varying time constants, state dependent noise, a graded firing threshold and time-inhomogeneous input. In the present study we build a jump diffusion model that incorporates these features, and introduce a firing mechanism with a state dependent intensity. In addition, we suggest statistical methods to estimate all unknown quantities and apply these to analyze turtle motoneuron membrane potentials. Finally, simulated and real data are compared and discussed. We find that a square-root diffusion describes the data much better than an Ornstein–Uhlenbeck process with constant diffusion coefficient. Further, the membrane time constant decreases with increasing depolarization, as expected from the increase in synaptic conductance. The network activity, which the neuron is exposed to, can be reasonably estimated to be a threshold version of the nerve output from the network. Moreover, the spiking characteristics are well described by a Poisson spike train with an intensity depending exponentially on the membrane potential

Wall shear stress estimated by 3D-QCA can predict cardiovascular events in lesions with borderline negative fractional flow reserve

Background and aims: There is some evidence of the implications of wall shear stress (WSS) derived from three-dimensional quantitative coronary angiography (3D-QCA) models in predicting adverse cardiovascular events. This study investigates the efficacy of 3D-QCA-derived WSS in detecting lesions with a borderline negative fractional flow reserve (FFR: 0.81–0.85) that progressed and caused events. Methods: In this retrospective cohort study, we identified 548 patients who had at least one lesion with an FFR 0.81–0.85 and complete follow-up data; 293 lesions (286 patients) with suitable angiographic characteristics were reconstructed using a dedicated 3D-QCA software and included in the analysis. In the reconstructed models blood flow simulation was performed and the value of 3D-QCA variables and WSS distribution in predicting events was examined. The primary endpoint of the study was the composite of cardiac death, target lesion related myocardial infarction or clinically indicated target lesion revascularization. Results: During a median follow-up of 49.4 months, 37 events were reported. Culprit lesions had a greater area stenosis [(AS), 66.1% (59.5–72.3) vs 54.8% (46.5–63.2), p<0.001], smaller minimum lumen area [(MLA), 1.66 mm2 (1.45–2.30) vs 2.10 mm2 (1.69–2.70), p=0.011] and higher maximum WSS [9.0 Pa (5.10–12.46) vs 5.0 Pa (3.37–7.54), p < 0.001] than those that remained quiescent. In multivariable analysis, AS [hazard ratio (HR): 1.06, 95% confidence interval (CI): 1.03–1.10, p=0.001] and maximum WSS (HR: 1.08, 95% CI: 1.02–1.14, p=0.012) were the only independent predictors of the primary endpoint. Lesions with an increased AS (≥58.6%) that were exposed to high WSS (≥7.69Pa) were more likely to progress and cause events (27.8%) than those with a low AS exposed to high WSS (7.4%) or those exposed to low WSS that had increased (12.8%) or low AS (2.7%, p<0.001). Conclusions: This study for the first time highlights the potential value of 3D-QCA-derived WSS in detecting, among lesions with a borderline negative FFR, those that cause cardiovascular events

Variability Measures of Positive Random Variables

During the stationary part of neuronal spiking response, the stimulus can be encoded in the firing rate, but also in the statistical structure of the interspike intervals. We propose and discuss two information-based measures of statistical dispersion of the interspike interval distribution, the entropy-based dispersion and Fisher information-based dispersion. The measures are compared with the frequently used concept of standard deviation. It is shown, that standard deviation is not well suited to quantify some aspects of dispersion that are often expected intuitively, such as the degree of randomness. The proposed dispersion measures are not entirely independent, although each describes the interspike intervals from a different point of view. The new methods are applied to common models of neuronal firing and to both simulated and experimental data

Predictive value of the QFR in detecting vulnerable plaques in non-flow limiting lesions: a combined analysis of the PROSPECT and IBIS-4 study

“This is a post-peer-review, pre-copyedit version of an article published in Int J Cardiovasc Imaging. The final authenticated version is available online at: https://doi.org/10.1007/s10554-020-01805-9”

Safety and efficacy of the supreme biodegradable polymer sirolimus-eluting stent in patients with diabetes mellitus

Patients with diabetes mellitus (DM) have worse outcomes following percutaneous coronary intervention than nondiabetic patients. The novel Supreme DES is a biodegradable polymer sirolimus-eluting stent designed to synchronize early drug delivery, limiting the potential for long-term inflammatory response. The purpose of this study was to evaluate the safety and efficacy of the Supreme DES in patients with DM. Methods This is a prespecified analysis of the diabetic subgroup from the PIONEER III randomized (2:1), controlled trial, comparing the Supreme DES with a durable polymer everolimus-eluting stent (DP-EES). The primary safety and efficacy composite endpoint was target lesion failure at 1 year, a composite of cardiac death, target vessel myocardial infarction, or clinically driven target lesion revascularization. Results The PIONEER III trial randomized 1629 patients, of which 494 (30.3%) had DM with 331 (398 lesions) randomly assigned to Supreme DES and 163 (208 lesions) to DP-EES. Among patients with DM, target lesion failure at 1 year was 6.1% (20/331) with Supreme DES vs 3.7% (6/163) with DP-EES (hazard ratio = 1.65; 95% confidence interval = 0.66-4.10, P = .28). The composite of cardiac death or target vessel myocardial infarction was 3.3% (11/331) with Supreme DES and 3.7% (6/163) with DP-EES (hazard ratio = 0.90; 95% confidence interval = 0.33-2.44, P = .83). There were no significant differences in other secondary endpoints. Conclusions This prespecified substudy of the PIONEER III trial demonstrated the relative safety and efficacy of the novel Supreme DES when compared with commercially available DP-EES in diabetics at 1 year. Longer term follow-up will be required to ensure continued safety and efficacy of the Supreme DES

Artificial Intelligence, Computational Simulations, and Extended Reality in Cardiovascular Interventions

Artificial intelligence, computational simulations, and extended reality, among other 21st century computational technologies, are changing the health care system. To collectively highlight the most recent advances and benefits of artificial intelligence, computational simulations, and extended reality in cardiovascular therapies, we coined the abbreviation AISER. The review particularly focuses on the following applications of AISER: 1) preprocedural planning and clinical decision making; 2) virtual clinical trials, and cardiovascular device research, development, and regulatory approval; and 3) education and training of interventional health care professionals and medical technology innovators. We also discuss the obstacles and constraints associated with the application of AISER technologies, as well as the proposed solutions. Interventional health care professionals, computer scientists, biomedical engineers, experts in bioinformatics and visualization, the device industry, ethics committees, and regulatory agencies are expected to streamline the use of AISER technologies in cardiovascular interventions and medicine in general

Comparing Respondent-Driven Sampling and Targeted Sampling Methods of Recruiting Injection Drug Users in San Francisco

The objective of this article is to compare demographic characteristics, risk behaviors, and service utilization among injection drug users (IDUs) recruited from two separate studies in San Francisco in 2005, one which used targeted sampling (TS) and the other which used respondent-driven sampling (RDS). IDUs were recruited using TS (n = 651) and RDS (n = 534) and participated in quantitative interviews that included demographic characteristics, risk behaviors, and service utilization. Prevalence estimates and 95% confidence intervals (CIs) were calculated to assess whether there were differences in these variables by sampling method. There was overlap in 95% CIs for all demographic variables except African American race (TS: 45%, 53%; RDS: 29%, 44%). Maps showed that the proportion of IDUs distributed across zip codes were similar for the TS and RDS sample, with the exception of a single zip code that was more represented in the TS sample. This zip code includes an isolated, predominantly African American neighborhood where only the TS study had a field site. Risk behavior estimates were similar for both TS and RDS samples, although self-reported hepatitis C infection was lower in the RDS sample. In terms of service utilization, more IDUs in the RDS sample reported no recent use of drug treatment and syringe exchange program services. Our study suggests that perhaps a hybrid sampling plan is best suited for recruiting IDUs in San Francisco, whereby the more intensive ethnographic and secondary analysis components of TS would aid in the planning of seed placement and field locations for RDS