Search

Transcatheter aortic valve implantation (TAVI) has revolutionized the management of patients with symptomatic severe aortic stenosis and has become the standard of care for inoperable patients and the preferred therapy for those at increased surgical risk with peculiar clinical and anatomic features. Technology advances, growing experience and accumulating data prompted the update of the 2011 Italian Society of Interventional Cardiology (SICI-GISE) position paper on institutional and operator requirements to perform TAVI. The main objective of this document is to provide a guidance to assess the potential of institutions and operators to initiate and maintain an efficient TAVI program. Transcatheter aortic valve implantation (TAVI) has revolutionized the management of patients with symptomatic severe aortic stenosis and has become the standard of care for inoperable patients and the preferred therapy for those at increased surgical risk with peculiar clinical and anatomic features. Technology advances, growing experience and accumulating data prompted the update of the 2011 Italian Society of Interventional Cardiology (SICI-GISE) position paper on institutional and operator requirements to perform TAVI. The main objective of this document is to provide a guidance to assess the potential of institutions and operators to initiate and maintain an efficient TAVI program.

Summary Background The Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox (MATRIX) programme was designed to assess the comparative safety and effectiveness of radial versus femoral access and of bivalirudin versus unfractionated heparin with optional glycoprotein IIb/IIIa inhibitors in patients with the whole spectrum of acute coronary syndrome undergoing invasive management. Here we describe the prespecified final 1-year outcomes of the entire programme. Methods MATRIX was a programme of three nested, randomised, multicentre, open-label, superiority trials in patients with acute coronary syndrome in 78 hospitals in Italy, the Netherlands, Spain, and Sweden. Patients with ST-elevation myocardial infarction were simultaneously randomly assigned (1:1) before coronary angiography to radial or femoral access and to bivalirudin, with or without post-percutaneous coronary intervention infusion or unfractionated heparin (one-step inclusion). Patients with non-ST-elevation acute coronary syndrome were randomly assigned (1:1) before coronary angiography to radial or femoral access and, only if deemed eligible to percutaneous coronary intervention after angiography (two-step inclusion), entered the antithrombin type and treatment duration programmes. Randomisation sequences were computer generated, blocked, and stratified by intended new or current use of P2Y12 inhibitor (clopidogrel vs ticagrelor or prasugrel), and acute coronary syndrome type (ST-elevation myocardial infarction, troponin-positive, or troponin-negative non-ST-elevation acute coronary syndrome). Bivalirudin was given as a bolus of 0·75 mg/kg, followed immediately by an infusion of 1·75 mg/kg per h until completion of percutaneous coronary intervention. Heparin was given at 70–100 units per kg in patients not receiving glycoprotein IIb/IIIa inhibitors, and at 50–70 units per kg in patients receiving glycoprotein IIb/IIIa inhibitors. Clinical follow-up was done at 30 days and 1 year. Co-primary outcomes for MATRIX access and MATRIX antithrombin type were major adverse cardiovascular events, defined as the composite of all-cause mortality, myocardial infarction, or stroke up to 30 days; and net adverse clinical events, defined as the composite of non-coronary artery bypass graft-related major bleeding, or major adverse cardiovascular events up to 30 days. The primary outcome for MATRIX treatment duration was the composite of urgent target vessel revascularisation, definite stent thrombosis, or net adverse clinical events up to 30 days. Analyses were done according to the intention-to-treat principle. This trial is registered with ClinicalTrials.gov, number NCT01433627. Findings Between Oct 11, 2011, and Nov 7, 2014, we randomly assigned 8404 patients to receive radial (4197 patients) or femoral (4207 patients) access. Of these 8404 patients, 7213 were included in the MATRIX antithrombin type study and were randomly assigned to bivalirudin (3610 patients) or heparin (3603 patients). Patients assigned to bivalirudin were included in the MATRIX treatment duration study, and were randomly assigned to post-procedure infusion (1799 patients) or no post-procedure infusion (1811 patients). At 1 year, major adverse cardiovascular events did not differ between patients assigned to radial access compared with those assigned to femoral access (14·2% vs 15·7%; rate ratio 0·89, 95% CI 0·80–1·00; p=0·0526), but net adverse clinical events were fewer with radial than with femoral access (15·2% vs 17·2%; 0·87, 0·78–0·97; p=0·0128). Compared with heparin, bivalirudin was not associated with fewer major adverse cardiovascular (15·8% vs 16·8%; 0·94, 0·83–1·05; p=0·28) or net adverse clinical events (17·0% vs 18·4%; 0·91, 0·81–1·02; p=0·10). The composite of urgent target vessel revascularisation, stent thrombosis, or net adverse clinical events did not differ with or without post-procedure bivalirudin infusion (17·4% vs 17·4%; 0·99, 0·84–1·16; p=0·90). Interpretation In patients with acute coronary syndrome, radial access was associated with lower rates of net adverse clinical events compared with femoral access, but not major adverse cardiovascular events at 1 year. Bivalirudin with or without post-procedure infusion was not associated with lower rates of major adverse cardiovascular events or net adverse clinical events. Radial access should become the default approach in acute coronary syndrome patients undergoing invasive management. Funding Italian Society of Invasive Cardiology, The Medicines Company, Terumo, amd Canada Research Chairs Programme.

The Order-Based Modal Analysis (OBMA) technique shows to be very powerful for identifying the modal parameters in operational conditions in case of rotating machineries during transient operations. The main idea behind the method is that instead of estimating the spectra and apply Operational Modal Analysis (OMA) by using them, the so-called orders can be extracted and used as input for the OMA technique. It can be assumed that the measured responses are mainly caused by the rotational excitation. In this case, run-up and coast-down events can be assimilated to multi-sine sweep excitation in the frequency band of interest. Several studies have been performed to identify the best practice for OBMA both in terms of Order Tracking (OT) techniques and OMA techniques. Based on the boundary conditions, on the structure under-test and on the effective operational conditions a technique can be more powerful than another one. Basically there are two fundamental steps: a very good measurement of the tachometer signal and the correct extraction of the orders, both in amplitude and phase. For the first step several alternatives are possible. The sensors to be used for measuring the rotational speed are depending from both the application and the objective of the study. For this reason, several sensors can be found in the market with a huge variety of costs and performances. The best sensor can then be selected for each individual application based on the type of analysis, the accessibility of the shaft, the ease of instrumentation and the required accuracy or level of detail. For the second step, several techniques are available in commercial software and some others have been implemented in a research environment. Each of them has its own advantages and drawbacks. The final aim of the work is to provide guidelines for the correct use of the OBMA technique in an industrial context. Several cases will be shown: a locomotive cabin and a car during engine run-ups and a 3.2 MW wind turbine gearbox during controlled run-ups on a test rig.

Atrial fibrillation (AF) is the most common arrhythmia and its prevalence is increasing due to the progressive aging of the population. About 20% of strokes are attributable to AF and AF patients are at five-fold increased risk of stroke. The mainstay of treatment of AF is the prevention of thromboembolic complications with oral anticoagulation therapy. Drug treatment for many years has been based on the use of vitamin K antagonists, but recently newer and safer molecules have been introduced (dabigatran etexilate, rivaroxaban, apixaban, and edoxaban). Despite these advances, many patients still do not receive adequate anticoagulation therapy because of contraindications (relative and absolute) to this treatment. Over the last decade, percutaneous closure of left atrial appendage, main site of thrombus formation during AF, proved effective in reducing thromboembolic complications, thus offering a valid medical treatment especially in patients at increased bleeding risk. The aim of this consensus document is to review the main aspects of left atrial appendage occlusion (selection and multidisciplinary assessment of patients, currently available methods and devices, requirements for centres and operators, associated therapies and follow-up modalities) having as a ground the significant evolution of techniques and the available relevant clinical data.

The aim of Operational Modal Analysis (OMA) is to estimate the modal parameters of a system in operating conditions. However, for the particular case of rotating machineries during run-up/run-down, it has been demonstrated that the method shows limitations because of the so-called “end-of-order effect”. This is one of the main reasons why new techniques have been explored. The most promising one is Order-Based Modal Analysis (OBMA), which combines advanced Order Tracking techniques with Operational identification methods. To validate this technique, a measurement campaign has been performed on a gear test rig. The test rig has been heavily instrumented to perform the validation of the proposed methodology, combining several triaxial accelerometers on the support plates and gears with state-of-the-art angular position transducers. Firstly, Experimental Modal Analysis (EMA) has been performed to identify a reference dataset. Then, OBMA has been applied on several run-ups/run-downs. The results of modal analysis on orders from different Order Tracking techniques has been compared to those obtained by EMA, confirming that OBMA is capable of correctly evaluating mode shapes and natural frequencies of the gear test rig from operational data.

In this paper a vibration-based approach to identify a crack in a wind turbine blade is described and demonstrated numerically and experimentally. Operational modal analysis has been performed before and after a buckling test, and vibration data, gathered from some accelerometers placed along the blade, was used to monitor the integrity of the structure, since the modal parameters are directly influenced by the physical properties of the structures. Additionally a numerical prediction has been done both with a full-scale model and with a one-dimensional model. The results show that this approach is able to estimate successfully the presence of damage and a good numerical and experimental correlation has been found. Finally, some considerations regarding the rotation of the blade in the undamaged and damaged cases have been done.

The growth of wind turbines in terms of power capacity and rotor diameter size has driven the research toward new studies and ideas. Nowadays high potential sites on land have already been taken and offshore locations need to be exploited taking advantage of the stronger wind. In 2009 a 5 MW concept has been proposed by NREL in order to be considered as the reference wind turbine for the next years. In 2013 a new reference model has been introduced by DTU Wind Energy, a 10 MW wind turbine. Both offshore wind turbines have been modeled by using an aeroelastic code and several simulations have been carried on with the main objective of developing advanced health monitoring techniques. As the first step to perform Structural health Monitoring (SHM) is the identification of the most sensitive parameters to structural degradation, advanced data analysis were developed. Methods such as the Multi-Blade Coordinate (MBC) transformation and the Harmonic Power Spectrum (HPS) have been validated and combined with Operational Modal Analysis to identify the modal parameters of the turbine in operational conditions, including sensors on the tower, blades and nacelle. Once the model and analysis techniques have been validated, damages have been introduced by adding lumped masses and by reducing the blades and/or the tower stiffness. Some SHM considerations have been drawn by analyzing the so-called whirling modes. They are due to the rotation of the blades and they can be observed only after that a pre-processing technique has been applied. They have been highlighted because they seem to be very sensitive to the introduction of small damages. doi: 10.12783/SHM2015/350

© The Society for Experimental Mechanics, Inc. 2014. The ability to identify the dynamic properties of offshore wind turbines allows validating and updating numerical tools, which can be used to enhance the design. At the same time, these dynamic parameters can serve as a basis to continuously monitor the integrity of the machine. However, modal identification of turbines in operating conditions still poses some major issues, in particular in removing the rotor harmonic components, which are polluting the measured signals. This paper will present and discuss some recent developments for removing harmonic components from operational wind turbine data. The possibility to track the evolution of specific modes is compared against classical techniques such as Time Synchronous Averaging and Cepstrum, which show limitations due to rotational speed fluctuations, amplitude modulation of the harmonic components and the interaction between the harmonics and the aerodynamic loads. The methodologies are firstly presented and then applied to real data of an offshore wind turbine installed in the Belgian North Sea. The ability to identify more accurately the modal parameters will allow improving the correlation with the varying environmental conditions and provide additional input data to validate numerical models. ispartof: pages:299-312 ispartof: Dynamics of Civil Structures vol:4 pages:299-312 ispartof: IMAC 2014 location:Orlando, FL, USA date:Feb - Feb 2014 status: published

© The Society for Experimental Mechanics, Inc. 2014. The aim of this paper is to characterize the dynamic behavior of a wind turbine gearbox installed on a dynamic test rig to replicate operational conditions. Wind turbines and gearboxes operate under very dynamic and complex conditions, caused by turbulent wind, fluctuations in the electricity grid etc. In those conditions, structural nonlinearities in bearings and gears cause natural frequencies to be significantly influenced by the operational conditions. To verify the dynamic response of a multi-megawatt gearbox, a comprehensive test campaign has been performed in the context of the European project ALARM at the ZF Wind Power test rig. Accelerations have been measured at more than 250 locations on the test rig and for different load levels and operating conditions. This paper focuses on the influence of the torque levels on the identified modal parameters. The acquired time histories during run-ups have been processed using different Operational Modal Analysis techniques. The aim is to provide a modal model that can be used for correlation and updating of a flexible nonlinear multibody model of the whole test rig as well as vibration levels to estimate structure-borne noise in the different operating conditions. ispartof: pages:41-52 ispartof: Topics in Modal Analysis vol:7 pages:41-52 ispartof: IMAC 2014 location:Orlando, FL, USA date:Feb - Feb 2014 status: published

This paper describes an extensive measurement campaign in order to characterize gearbox vibro-acoustic behavior. The measurements have been performed at ZF Wind Power on a 13.2MW test rig facility. Accelerations have been measured at more than 250 locations on the test rig and for different load levels and operating conditions. It is important to extract from the test rig measurements those parameters which are representative for the gearbox dynamic behavior. Several techniques, such as Operational Modal Analysis (OMA) and Order Based Modal Analysis (OBMA), have been applied to the acceleration data in order to extract the modal parameters in the test rig configuration. While the first technique shows some limitations, such as the so-called "end-of-order" effect, the second technique combining advanced Order Tracking with Operational Modal Analysis, does not suffer from "end-of-order" related peaks in the spectrum and identifies only the physical poles of the system. ispartof: pages:4349-4362 ispartof: PROCEEDINGS OF INTERNATIONAL CONFERENCE ON NOISE AND VIBRATION ENGINEERING (ISMA2014) AND INTERNATIONAL CONFERENCE ON UNCERTAINTY IN STRUCTURAL DYNAMICS (USD2014) pages:4349-4362 ispartof: ISMA 2014 location:Leuven, Belgium date:Sep - Sep 2014 status: published

Operational Modal Analysis (OMA), also known as output-only modal analysis, allows identifying modal parameters only by using the response measurements of the structures in operational conditions when the input forces cannot be measured. This information can then be used to improve numerical models in order to monitor the operating and structural conditions of the system. This is a critical aspect both for condition monitoring and maintenance of large wind turbines, particularly in the off-shore sector where operation and maintenance represent a high percentage of total costs. Although OMA is widely applied, the wind turbine case still remains an open issue. Numerical aeroelastic models could be used, once they have been validated, to introduce virtual damages to the structures in order to analyze the generated data. Results from such models can then be used as baseline to monitor the operating and structural condition of the machine. © (2013) Trans Tech Publications. ispartof: pages:523-530 ispartof: Key Engineering Materials vol:569 pages:523-530 ispartof: DAMAS 2013 location:Dublin date:Jul - Jul 2013 status: published

© Springer-Verlag Berlin Heidelberg 2014. Operational Modal Analysis (OMA), also known as output-only modal analysis, allows identifying modal parameters only by using the response measurements of the structures in operational conditions when the input forces cannot be measured. These information can then be used to improve numerical models in order to monitor the operating and structural conditions of the system. This is a critical aspect both for condition monitoring and maintenance of large wind turbines, particularly in the off-shore sector where operation and maintenance represent a high percentage of total costs. Although OMA is widely applied, the wind turbine case still remains an open issue. Numerical aeroelastic models could be used, once they have been validated, to introduce virtual damages to the structures in order to analyze the generated data. Results from such models can then be used as baseline to monitor the operating and structural condition of the machine. ispartof: pages:655-665 ispartof: Advances in Condition Monitoring of Machinery in Non-Stationary Operations vol:5 pages:655-665 ispartof: CMMNO 2013 location:Ferrara (Italy) date:May - May 2013 status: published

ispartof: pages:783-798 ispartof: PROCEEDINGS OF INTERNATIONAL CONFERENCE ON NOISE AND VIBRATION ENGINEERING (ISMA2014) AND INTERNATIONAL CONFERENCE ON UNCERTAINTY IN STRUCTURAL DYNAMICS (USD2014) pages:783-798 ispartof: ISMA 2014 location:Leuven, Belgium date:Sep - Sep 2014 status: published