Results 291 to 300 of about 107,940 (326)
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An Accelerated Fatigue Tester For Flexible Heart Valve Prostheses
Diseases of the Chest, 1964SUMMARY An accelerated fatigue pump for testing flexible prosthetic valves utilizing air as the activating medium for the valve has been developed and seems to fulfill the criteria for satisfactory testing of flex life in prosthetic valves. The design of the machine is described.
Harry D. Stokes, Hugh E. Wilson
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Durability of pyrolytic carbon‐containing heart valve prostheses
Journal of Biomedical Materials Research, 1982AbstractTo assess abrasive wear of mechanical valve prostheses containing pyrolytic carbon components, we recovered at necropsy or surgery and analyzed by scanning electron microscopy and surface profilometry eight prostheses. Seven were implanted for 30–85 (mean 50 months).
Gerald M. Lawrie +2 more
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Reoperations for Malfunction of Heart Valve Prostheses, Especially with Endocarditis
The Thoracic and Cardiovascular Surgeon, 1987Following the increasing number of patients with heart valve replacement and an extended indication (older age groups, acute infective endocarditis, multivalvular procedures) the indicence of malfunction of valve prostheses is continuously growing. The prognosis of patients with a malfunctioning prosthesis mainly depends on early diagnosis and adequate
Wolfgang Bircks +4 more
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Metal Wear in Lillehei‐Kaster Heart Valve Prostheses
Artificial Organs, 1985Abstract: Ten Lillehei‐Kaster heart valve prostheses, in situ for up to 10 years and recovered at surgery or necropsy, were examined by light and scanning electron microscopy. All showed metal wear on the luminal aspect of their struts. The volume of wear related to the duration a prosthesis had been in situ. The worn metal showed distinct, transverse
H. Alexander Heggtveit +3 more
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Wear Tests on Alumina for Application in Heart Valve Prostheses
Engineering in Medicine, 1984Medical grade alumina in a porous form, as well as the normal dense form, have been tested in a crossed-cylinder wear machine under conditions which reproduce those to be found in heart valves. The results show steady wear rates. For dense alumina pairs this rate is 9.9 × 10–7 mm3 (Nm)–1; for porous pairs it is about 10 times higher.
H Juden, C R Gentle
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Mechanical heart valve prostheses: sound level and related complaints
European Journal of Cardio-Thoracic Surgery, 1992In a randomised study, we investigated the sound production of mechanical heart valve prostheses and the complaints related to this sound. The CarboMedics, Björk-Shiley monostrut and StJude Medical prostheses were compared. A-weighted levels of the pulse-like sound produced by the prosthesis were measured in 25 patients after aortic valve replacement ...
Hero Wit, Tjark Ebels, Rrp Laurens
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Alternative causes of bioreaction to prosthetic heart valves: three cases with pannus formation.
Turk Kardiyoloji Dernegi arsivi : Turk Kardiyoloji Derneginin yayin organidir, 2014Pannus formation is an infrequent but serious complication of prosthetic heart valve surgery. The cause of pannus is recognized as a bioreaction to the prostheses; histological investigations have shown that pannus comprises collagen and elastic tissues ...
S. Karakoyun +4 more
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The Challenge of Assessing Heart Valve Prostheses by Doppler Echocardiography
Journal of the American Society of Echocardiography, 2009The assessment of prosthetic valve function remains challenging. Echocardiography has become the key diagnostic tool not only because of its noninvasive nature and wide availability but also because of limitations inherent in alternative diagnostic techniques.
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Thrombosis of mechanical heart valve prostheses: revisiting the role of fluoroscopy.
The British Journal of Radiology, 2000Prosthetic valve thrombosis is a rare but potentially fatal complication of heart valve replacement. Symptoms may be misleading, yet the condition may rapidly lead to death. A prompt diagnosis is therefore crucial. Ultrasound is the most often used technique for evaluating prosthesis dysfunction.
P. Montorsi, D. Cavoretto, G. Ballerini
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Pathogenesis of fungal infection on heart valve prostheses
Human Pathology, 1975Four patients with heart valve prostheses developed Candidate endocarditis. At autopsy the foci of infection were confined to patches of neoendocardium that appeared to have developed as ingrowths of host endocardium onto the sewing cloth of the artificial valve.
Stanley J. Robboy, John Kaiser
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