Results 241 to 250 of about 1,654 (283)
Some of the next articles are maybe not open access.
Mechanical Pulmonary Valve Replacement
Seminars in Thoracic and Cardiovascular Surgery: Pediatric Cardiac Surgery Annual, 2016Although most valve operations performed annually address lesions of the aortic or mitral valves, the frequency of pulmonary valve replacement (PVR) is increasing because most patients with congenital heart disease are surviving into the adult years. The vast majority of patients, especially children that require PVR, obtain a tissue valve because of ...
John M, Stulak +4 more
openaire +2 more sources
Evolution of mechanical heart valves
The Annals of Thoracic Surgery, 2000The need for prosthetic heart valves was long recognized but seemed an impossible dream before 1952 when Dr Charles Hufnagel clinically introduced a ball valve that he placed into the descending thoracic aorta for treatment of aortic valvular insufficiency.
R A, DeWall, N, Qasim, L, Carr
openaire +2 more sources
Mechanical Heart Valves in Children
Scandinavian Journal of Thoracic and Cardiovascular Surgery, 1984Longterm follow-up of 17 children, who consecutively underwent replacement of one cardiac valve with the Björk-Shiley prosthesis, is presented. The children's mean age was 8 years (range 4-12 years) and body weight 23.5 kg (range 15.0-38.4 kg) at the time of surgery 1970-80. Nine of the 17 operations (53%) were second-stage cardiac surgery.
A, Henze, D, Lindblom, V O, Björk
openaire +2 more sources
Mechanical Heart Valves in Septuagenarians
Journal of Cardiac Surgery, 2008To report on the use of a third-generation bileaflet mechanical valve in septuagenarians, selected to receive a mechanical valve, as compared to (a) a younger cohort undergoing same valve implant (study 1) and to (b) a matched group of septuagenarians undergoing biological implant (study 2).The study was carried out in a tertiary regional hospital in ...
Ascione, R +5 more
openaire +2 more sources
Mechanisms of Expiratory Valves Resistance
American Review of Respiratory Disease, 1988Abstract Expiratory valves are the major source of resistance in ventilator circuits. Some valves, particularly under certain conditions, cause high resistances. To establish the mechanisms of expiratory valve resistance (R), we measured R of 4 commercial valves under several experimental conditions.
R A, Kayaleh, A F, Wilson
openaire +2 more sources
Mechanism of the movements of the atrioventricular valves
The American Journal of Cardiology, 1966Abstract Ventricular pressure, ventricular diameter, atrial pressure, the pressure gradient across the A-V valve, and intraventricular heart sounds were recorded. The mechanisms producing closing and opening of the A-V valve were analyzed. There were two producing A-V valve closure. (1) Atrial contraction normally produces presystolic closure of the A-
openaire +2 more sources
Fluid Mechanics of Heart Valves
Annual Review of Biomedical Engineering, 2004▪ Abstract Valvular heart disease is a life-threatening disease that afflicts millions of people worldwide and leads to approximately 250,000 valve repairs and/or replacements each year. Malfunction of a native valve impairs its efficient fluid mechanic/hemodynamic performance.
Ajit P, Yoganathan +2 more
openaire +2 more sources
Mechanisms of aortic valve calcification
The American Journal of Cardiology, 2004The calcified aortic valve lesion develops in the setting of endothelial injury and inflammation and displays hallmarks of atherosclerosis, including lipids accumulation, matrix metalloproteinase activation, and interaction with renin-angiotensin system.
openaire +2 more sources
Axial Configuration of the Velopharyngeal Valve and Its Valving Mechanism
The Cleft Palate Craniofacial Journal, 1995The variability of the normal velopharyngeal (VP) closure mechanism was studied by investigating VP anatomy in relation to its closure mechanism in 60 patients. The axial configuration of the VP isthmus, as observed in axial CT scans at rest, was found to be correlated with VP function in terms of its closure patterns in speech as observed by ...
Y, Finkelstein +5 more
openaire +2 more sources
Mechanical heart valve cavitation in patients with bileaflet valves
2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2014Today, the quality of mechanical heart valves is quite high, and implantation has become a routine clinical procedure with a low operative mortality (< 5%). However, patients still face the risks of blood cell damage, thromboembolic events, and material failure of the prosthetic device.
Johansen, Peter +4 more
openaire +3 more sources