The Jyros bileaflet mechanical prosthesis is unique among bileaflet valve designs in that there is no fixed hinge mechanism and after implantation, the leaflets are free to rotate as determined by blood flow through the orifice. Between November 1992 and April 1994, 56 Jyros valves were implanted in 44 patients at 45 operations. There were 31 males and 13 females (ratio 2.3:1), with a mean age of 3714 and a range owelve patientsplacement (AVR) (26.7%), 19 had mitral valve replacement (MVR) (42.2%), and 14 had AVR plus MVR (DVR) (31.1%). In three DVR patients the Jyros valve was implanted only in the mitral position. There was one hospital death following DVR (2.3% mortality). Total follow-up of 341 patient-months (28.4 patient-years) is 100% complete. There were no late deaths. There was one reoperation for acute mitral prosthetic thrombosis (3.5%/patient-year). Another Jyros valve was inserted; leaving 53 valves at risk in 42 patients at the close of follow-up. There were no episodes of thromboembolism, transient ischemic attacks, endocarditis, hemolysis, or valve dysfunction, but three patients had four episodes of anticoagulant-related hemorrhage. Echocardiographic follow-up data was available in 29 patients and indicated satisfactory hemodynamic performance.(ABSTRACT TRUNCATED AT 250 WORDS)
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http://dx.doi.org/10.1111/j.1540-8191.1995.tb00588.x | DOI Listing |
J Artif Organs
December 2006
Department of Mechanical Engineering, Kanto Gakuin University, 1-50-1 Mutsuurahigashi, Kanazawa-ku, Yokoham 236-8501, Japan.
New dynamic particle image velocimetry (PIV) technology was applied to the study of the flow field associated with prosthetic heart valves. Four bileaflet prostheses, the St. Jude Medical (SJM) valve, the On-X valve with straight leaflets, the Jyros (JR) valve, and the Edwards MIRA (MIRA) valve with curved leaflets, were tested in the mitral position under pulsatile flow conditions to find the effect of the leaflet shape and overall valve design on the flow field, particularly in terms of the turbulent stress distribution, which may influence hemolysis, platelet activation, and thrombus formation.
View Article and Find Full Text PDFJ Artif Organs
January 2006
Department of Mechanical Engineering, College of Engineering, Kanto Gakuin University, 1-50-1 Mutsuura-higashi, Kanazawa-ku, Yokohama, 236-8501, Japan.
Dynamic particle image velocimetry (PIV) was applied to the study of the flow field associated with prosthetic heart valves. The results were compared with those of laser Doppler anemometry (LDA). Anatomically and antianatomically oriented Jyros (JR) and St.
View Article and Find Full Text PDFJ Artif Organs
January 2006
Department of Mechanical Engineering, College of Engineering, Kanto Gakuin University, 1-50-1 Mutsuura-higashi, Kanazawa-ku, Yokohama, 236-8501, Japan,
Antianatomically installed Jyros (JR) and ATS valves were compared with the St. Jude Medical (SJM) valve in the mitral position to study the effects of valve design on the downstream flow field and associated closing sounds using a particle image velocimetry (PIV) method utilizing a high-speed video flow visualization technique to map the velocity field and sound measurement to confirm claims by the manufacturer. Based on the experimental data, the following general conclusions can be made: in the velocity field directly below the mitral valve, where distinct characteristic differences in valve design can be seen, symmetrical twin circulations were observed because of the divergent nature of the flow generated by the two inclined half-disks installed in the antianatomical orientation; the SJM valve, which produced central downward circulation, is contrasted to the two other valves, which produced peripheral downward circulation.
View Article and Find Full Text PDFTunis Med
July 2004
Service de Cardiologie "Adultes" Hopital La Rabta, Tunis.
From 1981 to 1999 Mitral bileaflet prosthesis was implanted to 90 patients. Doppler echocardiography was performed for these patients between January and March 2002 with a mean deadline of 111 months after the intervention. 36 were women (40%) and 54 were men (60%) the mean age was 41 years (20 - 70 years) The mitral bileaflet prosthesis was a Saint Jude in 65 cases, Jyros 8 cases, Carbomédics 7 cases, Sorin Bicarbon 7 cases, Edwards Duromédics 2 cases et an ON-X in one case.
View Article and Find Full Text PDFJ Artif Organs
December 2003
Department of Mechanical Engineering, Kanto Gakuin University, 4834 Mutsuura, Kanazawa-ku, Yokohama 236-8501, Japan.
The Jyros (JR) and the Advancing The Standard (ATS) valves were compared with the St. Jude Medical (SJM) valve in the mitral position to study the effects of design differences, installed valve orientation to the flow, and closing sounds using particle tracking velocimetry and particle image velocimetry methods utilizing a high-speed video flow visualization technique to map the velocity field. Sound measurements were made to confirm the claims of the manufacturers.
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