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Background. Despite technical advancements, patients with sequential or diffuse coronary lesions undergoing percutaneous coronary intervention (PCI) have an increased risk of cardiovascular events at follow-up. We aimed to analyze the utility of a SyncVision/iFR (S-iFR)-guided PCI strategy versus an angiography-guided strategy in patients with this type of lesions. Methods. Randomized, multicenter, controlled, and open-label trial to compare S-iFR versus angiography-guided PCI in patients with sequential or diffuse angiographic coronary stenosis (ClinicalTrials.gov identifier: NCT04283734). The primary endpoint was the implanted stent length. The main secondary endpoint was targeting vessel failure (TVF) at one year. Results. A total of 100 patients underwent randomization, with 49 patients assigned to the S-iFR group and 51 to the angiography-guided PCI group. There were no differences between groups regarding clinical and anatomical characteristics. The baseline iFR was 0.71 ± 0.16 vs. 0.67 ± 0.19 (p = 0.279) in the S-iFR and angiography group, respectively. The mean lesion length was 42.3 ± 12 mm and 39.8 ± 12 (p = 0.297). The implanted stent length was 32.7 ± 17.2 mm in the S-iFR group and 43.1 ± 14.9 mm in the angiography group (mean difference, −10.4 mm; 95% confidence interval [CI], −16.9 to −4.0; p = 0.002). At one year, target vessel failure (TVF) occurred in four patients: three (6.1%) in the S-iFR group vs. one (1.9%) in the angiography group (p = 0.319). Conclusions. Among patients with sequential or long diffuse coronary lesions, a S-iFR-guided PCI strategy resulted in a reduction of the total stent length compared to an angiography-guided PCI strategy. A nonsignificant increase in TVF was observed in the S-iFR group. [ABSTRACT FROM AUTHOR]

Background: To assess whether hydrostatic pressure gradients caused by coronary height differences in supine versus prone positioning during invasive physiological stenosis assessment affect resting and hyperaemic pressure-based indices or coronary flow. Methods: Twenty-three coronary stenoses were assessed in twenty-one patients with stable coronary artery disease. All patients had a stenosis of at least 50% visually defined on previous coronary angiography. Pd/Pa, iFR, FFR, and coronary flow velocity (APV) measured using a Doppler were recorded across the same stenosis, with the patient in the prone position, followed by repeat measurements in the standard supine position. Results: When comparing prone to supine measurements in the same stenosis, in the LAD, there was a significant change in mean Pd/Pa of 0.08 ± 0.04 (p = 0.0006), in the iFR of 0.06 ± 0.07 (p = 0.02), and in the FFR of 0.09 ± 0.07 (p = 0.003). In the Cx, there was a change in mean Pd/Pa of 0.05 ± 0.04 (p = 0.009), iFR of 0.07 ± 0.04 (p = 0.01), and FFR of 0.05 ± 0.03 (p = 0.006). In the RCA, there was a change in Pd/Pa of 0.05 ± 0.04 (p = 0.032), iFR of 0.04 ± 0.05 (p = 0.19), and FFR of 0.04+−0.03 (p = 0.004). Resting and hyperaemic coronary flow did not change significantly (resting delta APV = 1.6 cm/s, p = 0.31; hyperaemic delta APV = 0.9 cm/s, p = 0.85). Finally, 36% of iFR measurements and 26% of FFR measurements were re-classified across an ischaemic threshold when prone and supine measurements were compared across the same stenosis. Conclusions: Pd/Pa, iFR, and FFR were affected by hydrostatic pressure variations caused by coronary height differences in prone versus supine positioning. Coronary flow did not change signifying a purely pressure-based phenomenon. [ABSTRACT FROM AUTHOR]

Background and Objectives: The revascularization strategy for percutaneous coronary intervention (PCI) in patients with multivessel (MV) acute coronary syndrome (ACS) remains controversial. Certain gaps in the evidence are related to the optimal timing of non-culprit lesion revascularization and the utility of instantaneous wave-free ratio (iFR) in the management of MV ACS intervention. The major benefits of iFR utilization in MV ACS patients in one-stage complete revascularization are: (1) the possibility to virtually plan the PCI, both the location and the extension of the necessary stenting to achieve the prespecified final hemodynamic result; (2) the opportunity to validate the final hemodynamic result of the PCI, both in culprit artery and all non-culprit arteries and (3) the value of obliviating the uncomfortable, costly, time consuming and sometimes deleterious effects from Adenosine, as there is no requirement for administration. Thus, iFR use fosters the achievement of physiologically appropriate complete revascularization in MV ACS patients during acute hospitalization. Materials and Methods: This pilot study was aimed to test the feasibility of a randomized trial research protocol as well as to assess patient safety signals of co-registration iFR-guided one-stage complete revascularization compared with that of standard staged angiography-guided PCI in de novo patients with MV ACS. This was a single-center, prospective, randomized, open-label clinical trial consecutively screening patients with ACS for MV disease. The intervention strategy of interest was iFR-guided physiologically complete one-stage revascularization, in which the virtual PCI planning of non-culprit lesions and the intervention itself were performed in one stage directly following treatment of the culprit lesion and other critical stenosis of more than ninety percent. Seventeen patients were recruited and completed the 3-month follow-up. Results: Index PCI duration was significantly longer while the volume of contrast media delivered in index PCI was significantly greater in the iFR-guided group than in the angiography-guided group (119.4 ± 40.7 vs. 47 ± 15.5 min, p = 0.004; and 360 ± 97.9 vs. 192.5 ± 52.8 mL, p = 0.003). There were no significant differences in PCI-related major adverse cardiovascular events (MACE) between the groups during acute hospitalization and at 3-months follow-up. One-stage iFR-guided PCI requires fewer PCI attempts until complete revascularization than does angiography-guided staged PCI. Conclusions: Complete revascularization with the routine use of the virtual planning tool in one-stage iFR-guided PCI is a feasible practical strategy in an everyday Cath lab environment following the protocol designed for the study. No statistically significant safety signals were documented in the number of PCI related MACE during the 3-month follow-up. [ABSTRACT FROM AUTHOR]

Combinations of multiple inorganic fillers have emerged as viable synergistic agents for boosting the flame retardancy of intumescent flame retardant (IFR) polymer materials. However, few studies on the effect of multiple inorganic fillers on the flame retardant behavior of rigid polyurethane (RPU) foam have been carried out. In this paper, a flame retardant combination of aluminum hydroxide (ATH) and traditional flame retardants ammonium polyphosphate (APP), pentaerythritol (PER), melamine cyanurate (MC), calcium carbonate (CC), and expandable graphite (EG) was incorporated into RPU foam to investigate the synergistic effects of the combination of multiple IFR materials on the thermal stability and fire resistance of RPU foam. Scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) revealed that 8 parts per hundred polyols by weight (php) filler concentrations were compatible with RPU foam and yielded an increased amount of char residue compared to the rest of the RPU samples. The flame retardancy of multiple fillers on intumescent flame retardant RPU foam was also investigated using cone calorimeter (CCTs) and limiting oxygen index (LOI) tests, which showed that RPU/IFR1 (APP/PER/MC/EG/CC/ATH) had the best flame retardant performance, with a low peak heat release rate (PHRR) of 82.12 kW/m2, total heat release rate (THR) of 15.15 MJ/m2, and high LOI value of 36%. Furthermore, char residue analysis revealed that the use of multiple fillers contributed to the generation of more intact and homogeneous char after combustion, which led to reduced decomposition of the RPU foam and hindered heat transfer between the gas and condensed phases. [ABSTRACT FROM AUTHOR]

After initially having low levels of SARS-CoV-2 infections for much of the year, Bulgaria experienced a major epidemic surge at the end of 2020, which caused the highest recorded excess mortality in Europe, among the highest in the word (Excess Mortality Rate, or EMR ∼0.25%). Two more major waves followed in 2021, followed by another one in early 2022. In this study, we analyze the temporal and spatial patterns of excess mortality at the national and local levels and across different demographic groups in Bulgaria and compare those to the European levels. Bulgaria has continued to exhibit the previous pattern of extremely high excess mortality, as measured both by crude mortality metrics (an EMR of ∼1.05%, up to the end of March 2022) and by standardized ones—Potential Years of Life Lost (PYLL) and Aged-Standardized Years of life lost Rate (ASYR). Unlike Western Europe, the bulk of excess mortality in Bulgaria, as well as in several other countries in Eastern Europe, occurred in the second year of the pandemic, likely related to the differences in the levels of vaccination coverage between these regions. We also observe even more extreme levels of excess mortality at the regional level and in some subpopulations (e.g., total EMR values for males ≥ 2% and EMR values for males aged 40–64 ≥ 1% in certain areas). We discuss these observations in light of the estimates of infection fatality rate (IFR) and eventual population fatality rate (PFR) made early in the course of the pandemic. [ABSTRACT FROM AUTHOR]

Haemodynamic indices are widely used in clinical practice when deciding on a particular type of treatment. Low quality of the computed tomography data and tachycardia complicate interpretation of the measured or simulated values. In this work, we present a novel approach for evaluating resistances in terminal coronary arteries. Using 14 measurements from 10 patients, we show that this algorithm retains the accuracy of 1D haemodynamic simulations in less detailed (truncated) geometric models of coronary networks. We also apply the variable systole fraction model to study the effect of elevated heart rate on the values of fractional flow reserve (FFR), coronary flow reserve (CFR) and instantaneous wave-free ratio (iFR). We conclude that tachycardia may produce both overestimation or underestimation of coronary stenosis significance. [ABSTRACT FROM AUTHOR]

Instantaneous wave-free ratio (iFR)-guided coronary revascularization has similar clinical outcomes compared to fractional flow reserve (FFR)-guided revascularization strategy. However, some studies have shown a discordance of around 20% between iFR and FFR. Although various factors have been reported in the literature to affect pressure indices and lead to such discordance, there is a paucity of data regarding the effect of diastolic dysfunction on functional assessment of coronary arteries. Our study aimed to investigate whether there was an association between echocardiographic left ventricular diastolic dysfunction and iFR/FFR discordance. This retrospective observational study evaluated 100 patients with angiographically intermediate coronary stenosis (50–70%) who underwent physiological testing with iFR and FFR. Transthoracic echocardiograms were reviewed to assess echocardiographic indices of diastolic function. The study population was divided into two groups based on diastolic function. iFR and FFR discordance was measured in each group and compared to evaluate the statistical difference. The mean age of the study population was 66.22 ± 10.02 years. Discordance between iFR and FFR was seen in 45.16% of patients with diastolic dysfunction compared to 24.64% of patients with normal diastolic function (p = 0.04). Multivariable logistic regression analysis indicated that echocardiographic E/e′ was independently associated with iFR/FFR discordance (p = 0.02). Left ventricular diastolic dysfunction is a significant factor that can lead to discordance between iFR and FFR and should be taken into account during coronary physiological testing. [ABSTRACT FROM AUTHOR]

Zinc oxide nanoparticles (ZnO NPs) were synthesized by a precipitation method, and a new charring–foaming agent (CFA) N-ethanolamine triazine-piperazine, melamine polymer (ETPMP) was synthesized via nucleophilic substitution reaction by using cyanuric chloride, ethanolamine, piperazine, and melamine as precursor molecules. FTIR and energy-dispersive X-ray spectroscopy (EDS) studies were employed to characterize and confirm the synthesized ETPMP structure. New intumescent flame retardant epoxy coating compositions were prepared by adding ammonium polyphosphate (APP), ETPMP, and ZnO NPs into an epoxy resin. APP and ETPMP were fixed in a 2:1 w/w ratio and used as an intumescent flame-retardant (IFR) system. ZnO NPs were loaded as a synergistic agent in different amounts into the IFR coating system. The synergistic effects of ZnO NPs on IFR coatings were systematically evaluated by limited oxygen index (LOI) tests, vertical burning tests (UL-94 V), TGA, cone calorimeter tests, and SEM. The obtained results revealed that a small amount of ZnO NPs significantly increased the LOI values of the IFR coating and these coatings had a V-0 ratings in UL-94 V tests. From the TGA data, it is clear that the addition of ZnO NPs could change the thermal degradation behaviors of coatings with increasing char residue percentage at high temperatures. Cone calorimeter data reported that ZnO NPs could decrease the combustion parameters including peak heat release rates (PHRRs), and total heat release (THR) rates. The SEM results showed that ZnO NPs could enhance the strength and the compactness of the intumescent char, which restricted the flow of heat and oxygen. [ABSTRACT FROM AUTHOR]