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Augmented and Virtual Visualization for Image-Guided Cardiac Therapeutics
Published in Terry M. Peters, Cristian A. Linte, Ziv Yaniv, Jacqueline Williams, Mixed and Augmented Reality in Medicine, 2018
Cristian A. Linte, Terry M. Peters, Michael S. Sacks
The standard of care for patients with severe aortic valve stenosis is open heart surgery, in which the patient is placed on cardiopulmonary bypass, allowing the surgeon direct tactile and visual access to the surgical target site. However, due to trauma associated with cardiopulmonary bypass and aortic cross clamping, up to one-third of all patients are deemed inoperable due to comorbidities such as pervious cardiac surgeries, chronic lung disease, or renal failure (Iung et al., 2005). In response to this problem, beating heart techniques are being developed. A stent-based, beating-heart aortic valve replacement was first performed in humans in 2002, with over 50,000 cases performed in over 40 countries since then (Haussig et al., 2014). Access to the aortic valve is achieved either transfemorally, via apical entry through the left ventricle (LV) or directly through incision into the descending aorta. The latter two techniques require a mini-thoracotomy for access but provide more direct control of the delivery tool. Stents are either made from a shape-memory alloy or use an inflatable balloon for deployment. Since their inception, a wide variety of devices have come on the market.
Sensor-Enabled 3D Printed Tissue-Mimicking Phantoms: Application in Pre-Procedural Planning for Transcatheter Aortic Valve Replacement
Published in Ayman El-Baz, Jasjit S. Suri, Cardiovascular Imaging and Image Analysis, 2018
Kan Wang, Chuck Zhang, Ben Wang, Mani A Vannan, Zhen Qian
The aortic valve is a heart valve situated between the left ventricle (LV) of the heart and the aorta. It functions like a one-way flow controller that allows blood from the LV to be pumped into the aorta but prevents the backflow of the blood. Aortic stenosis (AS), which is a narrowing of the aortic valve opening, is the most common valvular heart disease in developed countries [1]. Advanced age is a major risk factor of the development of AS. Some congenital heart defects, such as a bicuspid aortic valve, can also cause AS. The progression of AS involves a series of deteriorations of the cardiac function, including an elevated LV systolic pressure, LV concentric hypertrophy, an elevated LV diastolic pressure, and a decreased cardiac output. If untreated, AS patients ultimately develop heart failure.
Aortic Valve Mechanics
Published in Michel R. Labrosse, Cardiovascular Mechanics, 2018
J. Dallard, M. Boodhwani, M. R. Labrosse
Aortic valve replacement is the definitive therapy for severe AS (Vahanian et al., 2012); it typically involves open-chest surgery. Although a less invasive procedure, the transcatheter aortic valve implantation (TAVI) is increasingly recognized as a viable therapeutic option for a wider range of patients with severe AS (Masson et al., 2009). This procedure allows a bioprosthetic valve implantation by using a long narrow tube called a catheter. The bioprosthetic valve is delivered on a catheter through the femoral artery or the left ventricular apex (Smith et al., 2011). The TAVI devices include a rigid frame, for example, cobalt–chromium alloy, on which are sown cusps, manufactured from, for example, bovine pericardium (Bailey et al., 2016).
OpenModelica-based virtual simulator for the cardiovascular and respiratory physiology of a neonate
Published in Journal of Medical Engineering & Technology, 2022
Edgar Hernando Sepúlveda Oviedo, Leonardo Enrique Bermeo Clavijo, Luis Carlos Méndez Córdoba
This heart disease is a narrowing of the aortic valve opening. It can be represented, as depicted in Figure 4, by changing four parameters in the simulation diagram. Each parameter varies from a healthy reference value to a stenotic reference value. Therefore, parameter which decreases from to in component whereas parameters and must be increased in components and (as represented by blue arrows in Figure 4). This variation of parameters recreates the increase in mass of the cardiac muscle and the reduction in flow from the left ventricle to the aorta produced by Aortic Stenosis. The reference values assumed here (in both healthy a stenotic scenarios) are for a 6-month-old infant with a weight of 8 Kg (taken from Goodwin et al. [6]).
How valvular calcification can affect the outcomes of transcatheter aortic valve implantation
Published in Expert Review of Medical Devices, 2020
Stephan Milhorini Pio, Jeroen Bax, Victoria Delgado
In addition, the Transcatheter Aortic Valve Replacement to Unload the Left Ventricle in Patients with Advanced Heart Failure (TAVR-UNLOAD) trial randomizes patients with moderate AS and reduced left ventricular ejection fraction to TAVI or to medical therapy [87]. These patients usually undergo aortic valve replacement if an associated intervention is needed (particularly coronary revascularization). The hypothesis driving the trial is the fact that the stenotic aortic valve can superimpose a pressure overload to a dysfunctioning left ventricle and by replacing the valve, the hemodynamics of the left ventricle improve leading to better outcomes as compared to patients treated medically. Patients with moderate AS may have less calcium load of the aortic valve than the patients with severe AS and this may impact on the outcomes of TAVI. The prosthesis size may be larger to ensure stable implantation and reduce paravalvular leakage.
A biomechanical model of the pathological aortic valve: simulation of aortic stenosis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Marcos Loureiro-Ga, Cesar Veiga, Generosa Fdez-Manin, Victor Alfonso Jimenez, Francisco Calvo-Iglesias, Andres Iñiguez
The aortic valve (AV) is the anatomical structure that regulates the blood flow between the left ventricle in the heart and the systemic circulation through the aorta. Aortic Stenosis (AS) is the main pathology of the AV identified by a narrowing of the AV opening, altering the flow and which can cause several major health problems (Naghavi et al. 2013). It is characterized by progressive fibro-calcific remodelling and thickening of the AV leaflets that can evolve causing severe obstruction to cardiac outflow (Lindman et al. 2013). The process induces an additional effort to the heart, which needs to work harder to pump blood to the body and this extra work may eventually affect the heart muscle. Severe AS is a major cause of morbidity and mortality in the elderly (Freeman and Otto 2005) and with a projected 45% increase in the number of people aged 65 and over in the next 25 years in the EU (Eurostat 2012), a rise in the number of AS disease is expected.