Experimental investigation on particulate filters for heavy-duty natural gas engines: Potentialities toward EURO VII regulation.

The urgent need to meet the stringent regulation requirements on sub-23 nm particles emissions is pushing the interest towards efficient strategies for their reduction, involving different propulsive technologies, including the Natural Gas engines. Although considered as particulate matter-free, the growing diffusion of Natural Gas Heavy-Duty engines as a key element in the low-term towards decarbonization, requires their compliance with upcoming regulations. The use of particulate filters, in combination with the Three-Way Catalyst (TWC), could represent a promising and viable solution to achieve high conversion of gas-phase criteria pollutants and high particles filtration efficiency. The present activity arose from a collaboration among research groups of CNR-STEMS, FPT Industrial and NGK Europe GmbH, two industrial companies leaders in the topics here addressed. Target of the work is the evaluation of the potentiality offered by the use of filters in the abatement of particles emitted by a Natural Gas engine. Particles number, mass and size distribution analysis have been performed over the World Harmonized Transient Cycles. The exhaust line was properly designed to foresee the installation of particulate filter downstream a conventional TWC, in a close-coupled configuration. The filtration efficiency of two filters, from hereon termed as CNG Particulate Filters (CPFs), with different wall thickness and cell structures and a filter with catalytic coating, was compared. High particle abatement efficiency was found for all the filters, with values close to 90%, without noticeable increases in backpressures. The CPF with standard porosity showed the best performance, while no further significant benefits were found with the addition of a catalytic coating. The performed analysis places in an important emphasis in view of the forthcoming EURO VII regulations on PN limits (PN10) and sets the basis and direction for further optimization in filter material properties and catalyst coating in meeting stringent PN emission targets.

ECG analysis in patients with acute coronary syndrome undergoing invasive management: rationale and design of the electrocardiography sub-study of the MATRIX trial.

BACKGROUND: The twelve­lead electrocardiogram (ECG) has become an essential tool for the diagnosis, risk stratification, and management of patients with acute coronary syndromes (ACS). However, several areas of residual controversies or gaps in evidence exist. Among them, P-wave abnormalities identifying atrial ischemia/infarction are largely neglected in clinical practice, and their diagnostic and prognostic implications remain elusive; the value of ECG to identify the culprit lesion has been investigated, but validated criteria indicating the presence of coronary occlusion in patients without ST-elevation are lacking; finally, which criteria among the multiple proposed, better define pathological Q-waves or success of revascularisation deserve further investigations. METHODS: The Minimizing Adverse hemorrhagic events via TRansradial access site and systemic Implementation of AngioX (MATRIX) trial was designed to test the impact of bleeding avoidance strategies on ischemic and bleeding outcomes across the whole spectrum of patients with ACS receiving invasive management. The ECG-MATRIX is a pre-specified sub-study of the MATRIX programme which aims at analyzing the clinical value of ECG metrics in 4516 ACS patients (with and without ST-segment elevation in 2212 and 2304 cases, respectively) with matched pre and post-treatment ECGs. CONCLUSIONS: This study represents a unique opportunity to further investigate the role of ECGs in the diagnosis and risk stratification of ACS patients with or without ST-segment deviation, as well as to assess whether the radial approach and bivalirudin may affect post-treatment ECG metrics and patterns in a large contemporary ACS population.

Oral Antiplatelet Therapy for Secondary Prevention of Non-Cardioembolic Ischemic Cerebrovascular Events.

Stroke is the leading cause of disability and mortality worldwide. After an acute cerebrovascular ischemia, recurrent vascular events, including recurrent stroke or transient ischemic accidents (TIA), occur in around 20% of cases within the first 3 months. In order to minimize this percentage, antiplatelet therapy may play a key role in the management of non-cardioembolic cerebrovascular events. This review will focus on the current evidence of antiplatelet therapies most commonly discussed in practice guidelines and used in clinical practice for the treatment of stroke/TIA complications. The antiplatelet therapies most commonly used and discussed are as follows: aspirin, clopidogrel, and ticagrelor.

Prognostic Implications of Declining Hemoglobin Content in Patients Hospitalized With Acute Coronary Syndromes.

BACKGROUND: Contemporary definitions of bleeding endpoints are restricted mostly to clinically overt events. Whether hemoglobin drop per se, with or without overt bleeding, adversely affects the prognosis of patients with acute coronary syndrome (ACS) remains unclear. OBJECTIVES: The aim of this study was to examine in the MATRIX (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox) trial the incidence, predictors, and prognostic implications of in-hospital hemoglobin drop in patients with ACS managed invasively stratified by the presence of in-hospital bleeding. METHODS: Patients were categorized by the presence and amount of in-hospital hemoglobin drop on the basis of baseline and nadir hemoglobin values and further stratified by the occurrence of adjudicated in-hospital bleeding. Hemoglobin drop was defined as minimal (<3 g/dl), minor (≥3 and <5 g/dl), or major (≥5 g/dl). Using multivariate Cox regression, we modeled the association between hemoglobin drop and mortality in patients with and without overt bleeding. RESULTS: Among 7,781 patients alive 24 h after randomization with available hemoglobin data, 6,504 patients (83.6%) had hemoglobin drop, of whom 5,756 (88.5%) did not have overt bleeding and 748 (11.5%) had overt bleeding. Among patients without overt bleeding, minor (hazard ratio [HR]: 2.37; 95% confidence interval [CI]: 1.32 to 4.24; p = 0.004) and major (HR: 2.58; 95% CI: 0.98 to 6.78; p = 0.054) hemoglobin drop were independently associated with higher 1-year mortality. Among patients with overt bleeding, the association of minor and major hemoglobin drop with 1-year mortality was directionally similar but had wider CIs (minor: HR: 3.53 [95% CI: 1.06 to 11.79]; major: HR: 13.32 [95% CI: 3.01 to 58.98]). CONCLUSIONS: Among patients with ACS managed invasively, in-hospital hemoglobin drop ≥3 g/dl, even in the absence of overt bleeding, is common and is independently associated with increased risk for 1-year mortality. (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox; NCT01433627).

Prediction of radial crossover in acute coronary syndromes: derivation and validation of the MATRIX score.

BACKGROUND: The radial artery is recommended by international guidelines as the default vascular access in patients with acute coronary syndromes (ACS) managed invasively. However, crossover from radial to femoral access is required in 4-10% of cases and has been associated with worse outcomes. No standardised algorithm exists to predict the risk of radial crossover. AIMS: We sought to derive and externally validate a risk score to predict radial crossover in patients with ACS managed invasively. METHODS: The derivation cohort consisted of 4,197 patients with ACS undergoing invasive management via the randomly allocated radial access from the MATRIX trial. Using logistic regression, we selected predictors of radial crossover and developed a numerical risk score. External validation was accomplished among 3,451 and 491 ACS patients managed invasively and randomised to radial access from the RIVAL and RIFLE-STEACS trials, respectively. RESULTS: The MATRIX score (age, height, smoking, renal failure, prior coronary artery bypass grafting, ST-segment elevation myocardial infarction, Killip class, radial expertise) showed a c-index for radial crossover of 0.71 (95% CI: 0.67-0.75) in the derivation cohort. Discrimination ability was modest in the RIVAL (c-index: 0.64; 95% CI: 0.59-0.67) and RIFLE-STEACS (c-index: 0.66; 95% CI: 0.57-0.75) cohorts. A cut-off of ≥41 points was selected to identify patients at high risk of radial crossover. CONCLUSIONS: The MATRIX score is a simple eight-item risk score which provides a standardised tool for the prediction of radial crossover among patients with ACS managed invasively. This tool can assist operators in anticipating and better addressing difficulties related to transradial procedures, potentially improving outcomes.

Access-Site Crossover in Patients With Acute Coronary Syndrome Undergoing Invasive Management.

OBJECTIVES: The aim of this study was to assess the impact of access-site crossover in patients with acute coronary syndrome undergoing invasive management via radial or femoral access. BACKGROUND: There are limited data on the clinical implications of access-site crossover. METHODS: In the MATRIX (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox)-Access trial, 8,404 patients with acute coronary syndrome were randomized to radial or femoral access. Patients undergoing access-site crossover or successful access site were investigated. Thirty-day coprimary outcomes were a composite of death, myocardial infarction, or stroke (major adverse cardiovascular events [MACE]) and a composite of MACE or Bleeding Academic Research Consortium type 3 or 5 bleeding (net adverse clinical events [NACE]). RESULTS: Access-site crossover occurred in 183 of 4,197 patients (4.4%) in the radial group (mainly to femoral access) and 108 of 4,207 patients (2.6%) in the femoral group (mainly to radial access). In multivariate analysis, the risk for coprimary outcomes was not significantly higher with radial crossover compared with successful radial (MACE: adjusted rate ratio [adjRR]: 1.25; 95% confidence interval [CI]: 0.81 to 1.93; p = 0.32; NACE: adjRR: 1.40; 95% CI: 0.94 to 2.06; p = 0.094) or successful femoral access (MACE: adjRR: 1.17; 95% CI: 0.76 to 1.81; p = 0.47; NACE: adjRR: 1.26; 95% CI: 0.86 to 1.86; p = 0.24). Access site-related Bleeding Academic Research Consortium type 3 or 5 bleeding was higher with radial crossover than successful radial access. Femoral crossover remained associated with higher risks for MACE (adjRR: 1.84; 95% CI: 1.18 to 2.87; p = 0.007) and NACE (adjRR: 1.69; 95% CI: 1.09 to 2.62; p = 0.019) compared with successful femoral access. Results remained consistent after excluding patients with randomized access not attempted. CONCLUSIONS: Crossover from radial to femoral access abolishes the bleeding benefit offered by the radial over femoral artery but does not appear to increase the risk for MACE or NACE compared with successful radial or femoral access. (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox [MATRIX]; NCT01433627).

Coronary Physiology Assessment for the Diagnosis and Treatment of Coronary Artery Disease.

Functionally significant coronary lesions identification is necessary for appropriate revascularization. This review aims to provide an overview of the available options for coronary stenosis physiologic evaluation with a focus on the latest developments in the field.

Improving Adherence to Ticagrelor in Patients After Acute Coronary Syndrome: Results from the PROGRESS Trial.

BACKGROUND: Dual antiplatelet therapy (DAPT) with aspirin and ticagrelor is recommended for at least 12 months in patients after an acute coronary syndrome (ACS). However, its underuse and premature discontinuation are common in clinical practice. We aimed to investigate the impact of a dedicated follow-up strategy with clinical visits and counselling on adherence levels to ticagrelor in patients after ACS. METHODS: PROGRESS (PROmotinG dual antiplatelet therapy adheREnce in the setting of acute coronary Syndromes) is a prospective, randomized trial enrolling 400 ACS patients treated with ticagrelor. Patients were randomized to be followed-up in a dedicated outpatient clinic (In-person follow-up group, [IN-FU], n=200), or with scheduled for phone interviews only (Telephone follow-up group [TEL-FU], n=200), to assess ticagrelor adherence and related complications. DAPT disruption was defined as an interruption of the administration of the drug due to complications or other reasons of non-adherence, and divided according to the duration into short (1-5 days), temporary (6-30 days) and permanent (≥30 days) disruption. The primary endpoint was the rate of DAPT disruption at 1-year follow-up. RESULTS: The rate of ticagrelor disruption at 1 year follow-up was higher in the TEL-FU group than in the IN-FU group (19.6 vs 5.5%; p<0.0001). The IN-FU group reported a significantly lower rate of short (3.0 vs 8.5%; p=0.012) and permanent (2.0 vs 9.6%; p=0.012) disruption than TEL-FU group. The rate of major bleeding did not differ significantly between the 2 groups (p=0.450). CONCLUSION: The PROGRESS trial showed a net reduction in DAPT disruption in patients followed-up with clinical (in-person) follow-up visits in a dedicated outpatient clinic compared with those scheduled for phone interviews only.

Industrial-Graded Epoxy Nanocomposites with Mechanically Dispersed Multi-Walled Carbon Nanotubes: Static and Damping Properties.

The majority of currently published dispersion protocols of carbon nanotubes rely on techniques that are not scalable to an industrial level. This work shows how to obtain polymer nanocomposites with good mechanical characteristics using multi-walled carbon nanotubes epoxy resins obtained by mechanical mixing only. The mechanical dispersion method illustrated in this work is easily scalable to industrial level. The high shearing force due to the complex field of motion produces a good and reproducible carbon nanotube dispersion. We have tested an industrial epoxy matrix with good baseline mechanical characteristics at different carbon nanotube weight loads. ASTM-derived tensile and compressive tests show an increment in both Young's modulus and compressive strength compared with the pristine resin from a starting low wt %. Comparative vibration tests show improvement in the damping capacity. The new carbon nanotube enhanced epoxy resin has superior mechanical proprieties compared to the market average competitor, and is among the top products in the bi-components epoxy resins market. The new dispersion method shows significant potential for the industrial use of CNTs in epoxy matrices.