Науково-інформаційні ресурси порталу бібліотеки: формування, використання

Визначено шляхи вдосконалення процесів формування та використання електронних ресурсів порталу національної бібліотеки як базової компоненти єдиного науково-інформаційного простору держави.Определены пути усовершенствования процессов формирования и использования электронных ресурсов портала национальной библиотеки как базовой компоненты единого научно-информационного пространства государства.The ways of improvement of formation and usage processes of the electronic resources of the national library portal as a base component of unified scientific information space of the state are determined

Coronary fractional flow reserve measurements of a stenosed side branch: A computational study investigating the influence of the bifurcation angle

Background: Coronary hemodynamics and physiology specific for bifurcation lesions was not well understood. To investigate the influence of the bifurcation angle on the intracoronary hemodynamics of side branch (SB) lesions computational fluid dynamics simulations were performed. Methods: A parametric model representing a left anterior descending-first diagonal coronary bifurcation lesion was created according to the literature. Diameters obeyed fractal branching laws. Proximal and distal main branch (DMB) stenoses were both set at 60%. We varied the distal bifurcation angles (40°, 55°, and 70°), the flow splits to the DMB and SB (55%:45%, 65%:35%, and 75%:25%), and the SB stenoses (40, 60, and 80%), resulting in 27 simulations. Fractional flow reserve, defined as the ratio between the mean distal stenosis and mean aortic pressure during maximal hyperemia, was calculated for the DMB and SB (FFRSB) for all simulations. Results: The largest differences in FFRSB comparing the largest and smallest bifurcation angles were 0.02 (in cases with 40% SB stenosis, irrespective of the assumed flow split) and 0.05 (in cases with 60% SB stenosis, flow split 55%:45%). When the SB stenosis was 80%, the difference in FFRSB between the largest and smallest bifurcation angle was 0.33 (flow split 55%:45%). By describing the PSB-QSB relationship using a quadratic curve for cases with 80% SB stenosis, we found that the curve was steeper (i.e. higher flow resistance) when bifurcation angle increases (P=0.451*Q+0.010*Q 2 and P=0.687*Q+0.017*Q 2 for 40° and 70° bifurcation angle, respectively). Our analyses revealed complex hemodynamics in all cases with evident counter-rotating helical flow structures. Larger bifurcation angles resulted in more pronounced helical flow structures (i.e. higher helicity intensity), when 60 or 80% SB stenoses were present. A good correlation (R2=0.80) between the SB pressure drop and helicity intensity was also found. Conclusions: Our analyses showed that, in bifurcation lesions with 60% MB stenosis and 80% SB stenosis, SB pressure drop is higher for larger bifurcation angles suggesting higher flow resistance (i.e. curves describing the PSB-QSB relationship being steeper). When the SB stenosis is mild (40%) or moderate (60%), SB resistance is minimally influenced by the bifurcation angle, with differences not being clinically meaningful. Our findings also highlighted the complex interplay between anatomy, pressure drops, and blood flow helicity in bifurcations

Original Studies Outcomes of a Dedicated Stent in Coronary Bifurcations with Large Side Branches: A Subanalysis of the Randomized TRYTON Bifurcation Study

Objectives: To examine the benefit of the Tryton dedicated side branch (SB) stent compared with provisional stenting in the treatment of complex bifurcation lesions involving large SBs. Background: The TRYTON Trial was designed to evaluate the utility of a dedicated SB stent to treat true bifurcation lesions involving large (!2.5 mm by visual estimation) SBs. Patient enrolled in the trial had smaller SB diameters than intended (59% SB 2.25 mm by Core Lab QCA). The TRYTON Trial did not meet its primary endpoint due to an increased rate of peri-procedural myocardial infarctions (MIs). Methods: The TRYTON Trial randomized 704 patients to the Tryton SB stent with main vessel DES versus provisional SB treatment with main vessel DES. The rates of the primary end point of target vessel failure and the secondary powered end point of angiographic percent diameter stenosis in the SB at 9 months were assessed and compared between the two treatment strategies among patients with a SB !2.25 mm diameter at Additional Supporting Information may be found in the online version of this article. Catheterization and Cardiovascular Interventions 00:00-00 V C 2015 Wiley Periodicals, Inc

Contemporary techniques in percutaneous coronary intervention for bifurcation lesions

Introduction: Treatment of coronary bifurcation lesions with contemporary state-of-the-art percutaneous coronary intervention (PCI) is still associated with higher rate of adverse cardiovascular events compared to non-bifurcation lesions. Bench testing and virtual computer modeling have increased our understanding of bifurcation PCI guiding refinement in bifurcation techniques. New insights on bifurcation PCI have the potential to further improve clinical outcomes in patients presenting with bifurcation lesions. Areas covered: The present manuscript aims to review the methods for bifurcation lesion assessment and treatment strategy step by step supported on bench and clinical evidence. Expert commentary: Invasive pressure-wire evaluation is essential to determine the appropriateness of bifurcation PCI, particularly in intermediate coronary stenosis. Treatment strategy relies on four parameters: diameters of the three segments of the bifurcation; lesion length and plaque distribution; and bifurcation angle. The optimal technique for bifurcation PCI is still debated, an individualized approach with an initial provisional side branch stenting strategy seems to be suitable in the 75 to 95% of patients. For more complex bifurcations, two-stent techniques may be required with increasing evidence supporting the usefulness of the double kissing balloon crush (DK-crush) technique

A Narrative Review of Ultrathin-strut Drug-eluting Stents: The Thinner the Better?

Second-generation drug-eluting stents (DES) are considered standard of care for revascularization of patients undergoing percutaneous coronary intervention. Besides the polymer and antiproliferative drug used, the metallic backbone of DES is an attractive target for further development. Ultrathin-strut DES (≤70 µm strut thickness) are more flexible, have an improved trackability and crossability compared to conventional second-generation DES. Importantly, ultrathin-strut DES reduce the risk of in-stent restenosis, thereby decreasing the risk of angiographic and clinical restenosis. In this narrative review, we will discuss the clinical outcomes of the commercially available ultrathin-strut DES

Bioresorbable scaffolds in multivessel coronary disease

Bioresorbable technology has the potential to change the way interventional cardiology is being practiced in the coming years

The Tryton Side Branch Stent™ for the treatment of coronary bifurcation lesions

Coronary bifurcation lesions account for approximately 15% of all percutaneous coronary interventions (PCI) performed. Although clinical outcomes after PCI have been improved considerably, PCI of bifurcation lesions remains to be associated with adverse clinical events, when compared with non-bifurcation PCI. Therefore, several dedicated bifurcation devices have been developed to improve clinical outcomes. The Tryton Side Branch Stent(™) is such device and is used in combination with a regular tubular balloon expandable stent in the main branch. Multiple single and multicenter registries and a patient pooled analysis including 900 patients have shown promising results regarding clinical outcomes after bifurcation PCI with Tryton. The pivotal Tryton IDE randomized trial is currently underway comparing the Tryton stent with side branch balloon angioplasty as side branch treatment in bifurcation lesions challenging the current dogma of provisional single stent strategy as treatment for coronary bifurcation lesion