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st Century
Published in Tatiana G. Volova, Yuri S. Vinnik, Ekaterina I. Shishatskaya, Nadejda M. Markelova, Gennady E. Zaikov, Natural-Based Polymers for Biomedical Applications, 2017
Tatiana G. Volova, Yuri S. Vinnik, Ekaterina I. Shishatskaya, Nadejda M. Markelova, Gennady E. Zaikov
First surgeries to replace heart valves were performed in the 1960s. Now, heart valve replacement is a common clinical surgery. Heart valve disease is one of the causes of death of cardiac patients. Tens of thousands of replacement valves are implanted each year because of acquired damage to the natural valve and congenital heart anomalies. There are two main types of valve replacements – mechanical and biological substitute heart valves (Table 1.6). Aortic valves are normally repaired with an artificial mechanical or biological prosthesis and, while mitral valves can be replaced, many surgeons prefer to repair the existing valve by reshaping it. The life of biological valves is lower than the life of mechanical valves so, despite their rather less satisfactory flow characteristics, modern mechanical heart valves tend to be placed in young patients and may last for their whole lifetime. The life of biological valves is about 10 years, and they should not be implanted to patients with life expectancy over 10 years; otherwise, they need to be re-implanted. Mechanical valves are, however, thrombogenic, and patients with such valves always need anticoagulation treatment with such drugs as warfarin and heparin. Other drawbacks of mechanical valves are hemolysis (the rupturing of erythrocytes) and the high noise level. Thus, neither mechanical nor biological heart valves are perfect, and new-generation valves need to be designed.
in vitro Conditioning of Engineered Tissues
Published in Claudio Migliaresi, Antonella Motta, Scaffolds for Tissue Engineering, 2014
Aaron S. Goldstein, Patrick Thayer
Heart valve disease stems from the abnormal functioning of one or more of the valves of the heart due to inflammation or calcification. The progressive changes in tissue mechanics can lead to altered blood flow including regurgitation or stenosis. At present, severe
Novel Elastomers for Biomedical Applications
Published in Anil K. Bhowmick, Current Topics in ELASTOMERS RESEARCH, 2008
The growing interests in finding tissue-engineering solutions to the devastating worldwide problem of cardiovascular disease has prompted the attractions of PHAs in the heart valves and vessel patches tissue engineering.80–83
Off-the-shelf tissue engineered heart valves for in situ regeneration: current state, challenges and future directions
Published in Expert Review of Medical Devices, 2018
Sarah E. Motta, Valentina Lintas, Emanuela S. Fioretta, Simon P. Hoerstrup, Maximilian Y. Emmert
Congenital or acquired heart valve diseases and defects, such as valvular stenosis and valvular insufficiency, are nowadays treated with advanced procedures like valve repair or valve replacement. The treatment option depends on the type and severity of the valve disorder, and in case of severe aortic valve diseases, heart valve replacement represents the standard of care [1]. Current valve implantation techniques comprise open-heart surgery and transcatheter aortic valve replacement (TAVR). While the former is considered the preferred choice, the latter has tremendously advanced in the past years to treat patients with severe aortic valve stenosis ineligible or considered at high risk for surgical valve replacement [2,3]. TAVR options are less invasive for the patients and offer quicker recovery requiring shorter hospitalization than conventional open-heart surgery [4]. Recently, these techniques were shown to provide comparable or even superior results to surgical valve replacement, with regard to survival rate, cardiovascular mortality, complications, functionality, and hemodynamics [4–7]. In light of these advantages, TAVR has also been used to treat aortic valve regurgitation [7].
A portable Raspberry Pi-based system for diagnosis of heart valve diseases using automatic segmentation and artificial neural networks
Published in Cogent Engineering, 2020
Abdulkader Joukhadar, Louay Chachati, Mohammed Al-Mohammed, Obada Albasha
Valvular heart disease is caused by either damage or defect in one of the four heart valves, aortic, mitral, tricuspid, or pulmonary. Defects in these valves can be congenital or acquired (Kameswari et al., 2010; Zeng et al., 2016). Treatment of damaged valves may involve medication alone, but often involves surgical valve repair or replacement (insertion of an artificial heart valve) (Amirjani et al., 2014; Cabrera et al., 2017; Rick et al., 2014). Stenosis and regurgitation represent the conditions associated with valvular heart disease. Stenosis describes a narrowing of the valve opening that prevents adequate outflow of blood. Regurgitation describes the valve's inability to prevent backflow of blood as leaflets of the valve fail to close completely. In general, heart valve diseases include eight common classes, namely aortic stenosis, aortic regurgitation, mitral stenosis, mitral regurgitation, pulmonary stenosis, pulmonary regurgitation, tricuspid stenosis, and tricuspid regurgitation (Rick et al., 2014; Zeng et al., 2016). Doppler-echocardiography is today well-established tool in the diagnosis of heart valve diseases, but it is expensive. On the other hand, auscultation (analyzing cardiac sounds) is one of the cheap techniques commonly used by physicians for diagnosis. It is simple and effective; however, it needs long-term training and expertise (Singh et al., 2017). Therefore, many studies have been conducted toward designing systems based on the digital analysis of the phonocardiogram (PCG) signal in order to improve the diagnostic accuracy of physicians. In the field of heart valve disease diagnosis, which is based on PCG signals, most of the studies deal with computer-based systems that can only diagnose few valvular heart cases. Systems are devised in (Ahmad, 2011; Grzegorczyk et al., 2016; Hofmann et al., 2016) to interpret the condition of heart valves as normal or abnormal without further classifying the abnormal ones, while in (Emre & Uguz, 2011; Uğuz, 2012), the valvular heart condition is interpreted as one of the three cases (normal, mitral stenosis, pulmonary stenosis). Furthermore (Noman et al., 2018) presents a novel system to diagnose four valvular heart cases (normal, aortic regurgitation, mitral stenosis, mitral regurgitation), whereas in (Safara et al., 2013; Suboh et al., 2008; Suhas et al., 2017), five valvular heart cases (normal, aortic stenosis, aortic regurgitation, mitral stenosis, mitral regurgitation) are diagnosed. In (Kumar et al., 2018), a system is devised to diagnose five heart valve diseases (aortic stenosis, aortic regurgitation, mitral stenosis, mitral regurgitation, pulmonary stenosis). According to the aforementioned approaches, the maximum number of the diagnosed valvular heart cases is five, not to mention that the diagnosis process is performed by processing a pre-recorded PCG signal, which means these systems cannot clinically examine the patient to provide the diagnosis result as fast as possible.