Studio e sviluppo di compositi innovativi a matrice termoplastica per applicazione nel settore dei trasporti

Nano-/micro-composites based on polypropylene/MMT/calcium carbonate were prepared by melt mixing. Their structures and properties were characterized by small-angle X-Ray diffraction, thermal analysis, and rheological measurements. A Carreau-Yasuda model was used to model the rheological behaviour of these materials. The nano-/micro-composites showed a significant improvement (about 50%) of the Young’s modulus when compared to micro-composites with the same filler content due to the intercalation or exfoliation of the organoclay and the enhanced degree of crystallinity. The composite is build up by alternating layers of micro and/or nano reinforced thermoplastic matrix materials and woven fibre reinforcement. Micro and micro/nano-composites have the potential to improve the matrix dominated flexural properties of continuous fibre reinforced composites by means of increasing the matrix modulus. The effects of matrix composition, polymeric film thickness and processing conditions on viscoelastic and mechanical properties of the final multilayered thermoplastic composites are discussed. During this process, the thermoplastic matrix containing micro particles is squeezed out due to the flow of the macromolecular phase into the reinforcing woven fibers. The filler concentration in the interlayer is therefore higher than the initial value and the final multilayered composite structure is characterized by alternating layers of continuous fiber reinforced laminas of nanoreinforced matrices and micro-sized rich particulate composites. The damping properties of this structures can be therefore designed by tuning the initial composition of the particulate reinforced composites and its thickness in the multilayered structure

Catalytic Combustion of Waste Streams Coming from the Solvent Recovery Stage of a Packaging Industry

Esters and alcohols are widely used as solvents in the packaging industry. They contribute to the increase of volatile organic compound (VOC) emissions and, as such, represent a serious air pollution problem that must be faced. To this end, two main strategies can be pursued: solvent recovery and/or incineration, the former being of course preferred. Solvent recovery consists of an activated carbon plant, which adsorbs the post-printing exhaust solvents, and a distillation system, which separates the recovered solvent mixture. The waste streams coming from the solvent recovery stage need to be disposed, implying additional costs as well as safety issues. In this work, a low-cost perovskite-based catalyst, doped with a low amount of noble metal (Pt) and supported over a monolithic reactor, was used to run lab-scale combustion tests for waste streams coming from the solvent recovery stage of the packaging industry Icimendue (www.icimen.com). Results of experimental tests support the validity of catalytic combustion of the waste streams as an alternative approach to their disposal

Antithrombotic Management during Percutaneous Mitral Valve Repair with the Mitraclip System in a Patient with Heparin-Induced Thrombocytopenia

Interventional cardiology procedures require full anticoagulation to prevent thrombus formation on catheters and devices with potential development of embolic complications. Bivalirudin, a short half-life direct thrombin inhibitor, has been largely used during percutaneous coronary interventions and represents the preferred alternative to heparin in patients with heparin-induced thrombocytopenia (HIT). However, few data are available about intraprocedural use of bivalirudin during transcatheter structural heart disease interventions. Activated clotting time (ACT) monitoring during bivalirudin infusion pre- sents some limitations and it is not mandatory. We report a case of bivalirudin use in a patient with type-2 HIT during percutaneous mitral valve repair with the Mitraclip system (Abbott, Abbott Park, Illinois, United States). Despite use of standard bivalirudin dose (0.75 mg/kg bolus and 1.4 mg/kg/min infusion—reduced infusion rate was motivated by a glomerular filtration rate of 37 mL/min), the patient developed a large thrombus on the second clip during its orientation toward the mitral orifice. ACT was measured at that time and was suboptimal (240 seconds). The case was successfully managed with clip and thrombus retrieval, adjunctive 0.3 mg/kg bivalirudin bolus and increased infusion rate, and clip repositioning with ACT monitoring. This report makes the case for mandatory ACT checking and drug titration during high-risk catheter–based structural heart disease interventions, even when thromboprophylaxis is performed with bivalirudin. Additional coagulation tests may be useful to monitor bivalirudin response in similar cases

Usefulness of Electrocardiographic Patterns at Presentation to Predict Long-term Risk of Cardiac Death in Patients With Hypertrophic Cardiomyopathy

The objective of this study was to investigate the prognostic significance of 12-lead electrocardiogram (ECG) patterns in a large multicenter cohort of patients with hypertrophic cardiomyopathy; 1,004 consecutive patients with hypertrophic cardiomyopathy and a recorded standard ECG (64% men, mean age 50 ± 16 years) were evaluated at 4 Italian centers. The study end points were sudden cardiac death (SCD) or surrogates, including appropriate implanted cardiac defibrillator discharge and resuscitated cardiac arrest and major cardiovascular events (including SCD or surrogates and death due to heart failure, cardioembolic stroke, or heart transplantation). Prevalence of baseline electrocardiographic characteristics was: normal ECG 4%, ST-segment depression 56%, pseudonecrosis waves 33%, "pseudo-ST-segment elevation myocardial infarction (STEMI)" pattern 17%, QRS duration ≥120 ms 17%, giant inverted T waves 6%, and low QRS voltages 3%. During a mean follow-up of 7.4 ± 6.8 years, 77 patients experienced SCD or surrogates and 154 patients experienced major cardiovascular events. Independent predictors of SCD or surrogates were unexplained syncope (hazard ratio [HR] 2.5, 95% confidence interval [CI] 1.4 to 4.5, p = 0.003), left ventricular ejection fraction <50% (HR 3.5, 95% CI 1.9 to 6.7, p = 0.0001), nonsustained ventricular tachycardia (HR 1.7, 95% CI 1.1 to 2.6, p = 0.027), pseudo-STEMI pattern (HR 2.3, 95% CI 1.4 to 3.8, p = 0.001), QRS duration ≥120 ms (HR 1.8, 95% CI 1.1 to 3.0, p = 0.033), and low QRS voltages (HR 2.3, 95% CI 1.01 to 5.1, p = 0.048). Independent predictors of major cardiovascular events were age (HR 1.02, 95% CI 1.01 to 1.03, p = 0.0001), LV ejection fraction <50% (HR 3.73, 95% CI 2.39 to 5.83, p = 0.0001), pseudo-STEMI pattern (HR 1.66, 95% CI 1.13 to 2.45, p = 0.010), QRS duration ≥120 ms (HR 1.69, 95% CI 1.16 to 2.47, p = 0.007), and prolonged QTc interval (HR 1.68, 95% CI 1.21 to 2.34, p = 0.002). In conclusion, a detailed qualitative and quantitative electrocardiographic analyses provide independent predictors of prognosis that could be integrated with the available score systems to improve the power of the current model

Antithrombotic Management during Percutaneous Mitral Valve Repair with the Mitraclip System in a Patient with Heparin-Induced Thrombocytopenia

Interventional cardiology procedures require full anticoagulation to prevent thrombus formation on catheters and devices with potential development of embolic complications. Bivalirudin, a short half-life direct thrombin inhibitor, has been largely used during percutaneous coronary interventions and represents the preferred alternative to heparin in patients with heparin-induced thrombocytopenia (HIT). However, few data are available about intraprocedural use of bivalirudin during transcatheter structural heart disease interventions. Activated clotting time (ACT) monitoring during bivalirudin infusion pre- sents some limitations and it is not mandatory. We report a case of bivalirudin use in a patient with type-2 HIT during percutaneous mitral valve repair with the Mitraclip system (Abbott, Abbott Park, Illinois, United States). Despite use of standard bivalirudin dose (0.75 mg/kg bolus and 1.4 mg/kg/min infusion\u2014reduced infusion rate was motivated by a glomerular filtration rate of 37 mL/min), the patient developed a large thrombus on the second clip during its orientation toward the mitral orifice. ACT was measured at that time and was suboptimal (240 seconds). The case was successfully managed with clip and thrombus retrieval, adjunctive 0.3 mg/kg bivalirudin bolus and increased infusion rate, and clip repositioning with ACT monitoring. This report makes the case for mandatory ACT checking and drug titration during high-risk catheter\u2013based structural heart disease interventions, even when thromboprophylaxis is performed with bivalirudin. Additional coagulation tests may be useful to monitor bivalirudin response in similar cases

Modifications of medical treatment and outcome after percutaneous correction of secondary mitral regurgitation

Aims: The optimization of guideline-directed medical therapy (GDMT) in reduced ejection fraction heart failure (HFrEF) is associated with improved survival and can reduce the severity of secondary mitral regurgitation (SMR). Highest tolerated doses should be achieved before percutaneous mitral valve repair (pMVR) and drugs titration further pursued after procedure. The degree of GDMT titration in patients with HFrEF and SMR treated with pMVR remains unexplored. We sought to evaluate the adherence to GDMT in HFrEF in patients undergoing pMVR and to explore the association between changes in GDMT post-pMVR and prognosis. Methods and results: We included all the patients with HFrEF and SMR 65 3 + treated with pMVR between 2012 and 2019 and with available follow-up. GDMT, comprehensive of dosages, was systematically recorded. The study endpoint was a composite of death and heart transplantation. Among 133 patients successfully treated, 121 were included (67 \ub1 12 years old, 77% male patients). Treatment rates of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers/angiotensin receptor neprilysin inhibitor (ACEIs/ARBs/ARNI), beta-blockers, and mineralcorticoid receptor antagonist at baseline and follow-up were 73% and 79%, 85% and 84%, 70% and 70%, respectively. At baseline, 33% and 32% of patients were using >50% of the target dose of ACEI/ARB/ARNI and beta-blockers. At follow-up (median time 4 months), 33% of patients unchanged, 34% uptitrated, and 33% of patients downtitrated GDMT. Downtitration of GDMT was independently associated with higher risk of death/heart transplantation (hazard ratio: 2.542, 95%confidence interval: 1.377-4.694, P = 0.003). Conclusions: Guideline-directed medical therapy is frequently underdosed in HFrEF patients with SMR undergoing pMVR. Downtitration of medications after procedure is associated with poor prognosis

Risk of Adverse Cardiac and Bleeding Events Following Cardiac and Noncardiac Surgery in Patients with Coronary Stent: How Important Is the Interplay between Stent Type and Time from Stenting to Surgery?

Background - Epidemiology and consequences of surgery in patients with coronary stents are not clearly defined, as well as the impact of different stent types in relationship with timing of surgery. Methods and Results - Among 39 362 patients with previous coronary stenting enrolled in a multicenter prospective registry and followed for 5 years, 13 128 patients underwent 17 226 surgical procedures. The cumulative incidence of surgery at 30 days, 6 months, 1 year, and 5 years was 3.6%, 9.4%, 14.3%, and 40.0%, respectively, and of cardiac and noncardiac surgery was 0.8%, 2.1%, 2.6%, and 4.0% and 1.3%, 5.1%, 9.1%, and 31.7%, respectively. We assessed the incidence and the predictors of cardiac death, myocardial infarction, and serious bleeding event within 30 days from surgery. Cardiac death occurred in 438 patients (2.5%), myocardial infarction in 256 (1.5%), and serious bleeding event in 1099 (6.4%). Surgery increased 1.58× the risk of cardiac death during follow-up. Along with other risk factors, the interplay between stent type and time from percutaneous coronary intervention to surgery was independently associated with cardiac death/myocardial infarction. In comparison with bare-metal stent implanted >12 months before surgery, old-generation drug-eluting stent was associated with higher risk of events at any time point. Conversely, new-generation drug-eluting stent showed similar safety as bare-metal stent >12 months and between 6 and 12 months and appeared trendly safer between 0 and 6 months. Conclusions - Surgery is frequent in patients with coronary stents and carries a considerable risk of ischemic and bleeding events. Ischemic risk is inversely related with time from percutaneous coronary intervention to surgery and is influenced by stent type

Percutaneous mitral valve repair: The last chance for symptoms improvement in advanced refractory chronic heart failure?

Background The role of percutaneous mitral valve repair (PMVR) in patients with end-stage heart failure (HF) and functional mitral regurgitation (FMR) is unclear. Methods Seventy-five consecutive patients with FMR grade ≥ 3 + and severe HF symptoms despite optimal medical therapy and resynchronization therapy underwent PMVR with the MitraClip system (Abbott, Abbott Park, IL, USA) at 3 centers. Clinical evaluation, echocardiography and pro-BNP measurement were performed at baseline and at 6-month. Results Mean age was 67 ± 11 years, logistic EuroSCORE = 23 ± 18%, left ventricle ejection fraction (LVEF) 30 ± 9%. In 6 patients (8%) PMVR was performed as a bridge to heart transplant; many patients were dependent from iv diuretics and/or inotropes. Rate of serious adverse in-hospital events was 1.3% (1 patient who died after conversion to cardiac surgery). Sixty-three patients (84%) were discharged with MR ≤ 2 +. At 6-month, 4 patients died (5%), 80% had MR ≤ 2 + and 75% were in New York Heart Association class ≤ II. Median pro-BNP decreased from 4395 pg/ml to 2594 pg/ml (p = 0.04). There were no significant changes in LV end-diastolic volume (222 ± 75 ml vs. 217 ± 79, p = 0.19), end-systolic volume (LVESV, 154 ± 66 ml vs. 156 ± 69, p = 0.54) and LVEF (30 ± 9% vs. 30 ± 12%, p = 0.86). Significant reverse remodeling (reduction of LVESV ≥ 10%) was observed in 25%, without apparent association with baseline characteristics. The number of hospitalizations for HF in comparison with the 6 months before PMVR were reduced from 1.1 ± 0.8 to 0.3 ± 0.6 (p < 0.001). Conclusions In extreme risk HF patients with FMR, PMVR improved symptoms and reduced re-hospitalization and pro-BNP levels at 6 months, despite the lack of LV reverse remodeling