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Results for “HEART VALVE PROSTHESIS”

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At least 109 records · Page 6Linked to original sources
PubMed1990

[Problems of surgical treatment of dysfunction of heart valve prosthesis].

The article generalizes experience in surgical treatment of disturbed functioning of heart valve prostheses. Functioning was impaired in 3.2% of 5113 prostheses. Operations were repeated in disturbed functioning of heart valve prostheses in 58 (35.4%) patients, in 7 of them the intervention was repeated twice. Closure of fistulas (26.2%) is possible only in moderate paravalvular+ insufficiency which is not connected with septic endocarditis. The authors emphasize the great risk of repeated operations, which calls for special attention to be paid to the prevention of disturbed functioning of heart valve prostheses.

Aortic Valve Insufficiency↗
PubMed1994

In vitro fluid dynamic evaluation of the Carbomedics bileaflet heart valve prosthesis in the aortic and mitral positions.

Since the introduction of bileaflet heart valve prostheses their clinical use has continued to escalate. The first of this valve type was the Standard St. Jude Medical (SSJM) prosthetic heart valve in 1977. The Carbomedics prosthetic heart valve (CPHV), introduced in the late 1980s, was intended to improve on the design of the SSJM bileaflet valve. The design changes in the CPHV valve, relative to the SSJM valve, may have the potential to affect its flow fields. This study, using flow visualization laser Doppler velocity measurements and color Doppler flow mapping, was intended to evaluate how these changes affect the flow fields in the near vicinity of the CPHV valve. The study was conducted in an in vitro pulse duplicator system. In the flow visualization study, the flow fields observed with the CPHV valve were quantitatively similar to those seen with the SSJM valve. Centralized jet-like flows with flow separation/stagnation were observed in the illuminated planes. The jet-like flows from the two lateral orifices were broader than that observed from the central orifice for both the CPHV and the SSJM valves. This fact implied that the major part of the volumetric flow was through the two lateral orifices, rather than the central orifice. In the laser Doppler velocity measurements, it was found that the flow field downstream of the SSJM valve was slightly more evenly distributed than that with the CPHV valve. In addition, the extent of the flow separation regions with the CPHV valve were slightly larger than with the SSJM valve. The slight differences in velocity profiles between the SSJM and the CPHV valves were due to the differences in leaflet opening angle. However, the levels of flow turbulence with the CPHV and the SSJM valves were found to be of the same order of magnitude. The results of the flow visualization and LDA velocity and turbulence measurements obtained in the study indicate that the differences in flow fields in the immediate vicinity of the CPHV valve relative to the SSJM valve are insignificant.

Aortic Valve↗
PubMed1996

Impact of mechanical heart valve prosthesis sound on patients' quality of life.

BACKGROUND: The "click" sound of mechanical heart valve prostheses has been recognized as a disturbing factor for some patients after mechanical heart valve implantation. The factors determining the extent of disturbance remain controversial. METHODS: Ninety-five unmatched patients with six different valve types were examined (Duromedics-Edwards, Björk-Shiley, St. Jude Medical, Medtronic, CarboMedics, and Omnicarbon), including 12 patients with double-valve replacement. Three groups (Björk-Shiley, Duromedics-Edwards, and St. Jude Medical) were comparable in size. All patients were examined and interviewed, a hearing test was performed, and valve sounds were analyzed. Sound transmission was evaluated. RESULTS: The loudest valve was the Duromedics-Edwards prosthesis (mean, 84.2 dB[A] impulse) and the St. Jude Medical was the quietest (mean, 73.5 dB[A] impulse). This ranking was independent of patient variables and valve position. Discomfort level correlated with hearing loss and loudness of the valve. Patients desiring a quieter valve had better hearing, had louder valve sounds, felt disturbed by the sound, had partners who felt disturbed, and were receiving coumarin for anticoagulation. Sound was transmitted predominantly by air conduction. The frequency analysis to identify different valves was unsatisfactory, but louder frequencies did correspond with hearing-impaired patients' audiograms. CONCLUSIONS: Our results emphasize the need for valve design changes, preoperative education about the sound, and inclusion of routine hearing tests into the preoperative workup.

Adult↗
PubMed2001

[Prognostication of the outcome of heart valve prosthesis implantation by the method of nonlinear chaos dynamics of the heart rate].

An examination of 39 patients with heart diseases was performed before and after operations by the method of geometrical analysis of the nonlinear chaos (fractal) variability of the cardiac rhythm on the basis of the apparatus-programmed complex "Poly-spectrum". Five-minute-long registrations of ECG were carried on. On the basis of the data of examination of 195 healthy volunteers the reference norm of this method parameters was determined. Reliably lower parameters were found in patients with the acquired valvular disease. A dynamic investigation of the geometrical nonlinear structure of the cardiac rhythm has shown the possibility to make a prognosis of early complications after prosthetics of the heart valves.

Adult↗
PubMed1982

In vitro fluid dynamic characteristics of the Medtronic-Hall pivoting disc heart valve prosthesis.

The need for better low-profile mechanical valves led to the design and development of the Medtronic-Hall (formerly known as the Hall-Kaster valve) pivoting disc heart valve prosthesis in 1976. In vitro flow studies indicate that it has improved pressure drop characteristics compared to the Lillehei-Kaster and convexoconcave Björk-Shiley (60 degrees model) tilting disc valves. It does, however, have a somewhat larger regurgitant volume compared to the Björk-Shiley valve design. Velocity measurements with a laser-Doppler anemometer in the immediate downstream vicinity of the Medtronic-Hall valve indicate no region of stagnation near the outflow face of the disc. Regions of stagnation were, however, observed adjacent to the two titanium "pivot stops" situated on either side of the disc in the major orifice and along the pivot post in the minor orifice, together with a region of flow separation adjacent to the sewing ring of the minor outflow region. The results of the present in vitro study indicate a small but significant improvement in the overall fluid dynamic performance of the Medtronic-Hall valve, compared to the convexo-concave Björk-Shiley (60 degrees model) and Lillehei-Kaster tilting disc prostheses in current clinical use.

Aortic Valve↗
PubMed1979

[Heart valve prosthesis and pregnancy].

Sixteen pregnancies were followed up in 13 patients with prosthetic heart valves: 8 pregnancies went to term under oral anticoagulation, 4 under heparin and 4 without anticoagulation. 9 healthy normal children were delivered; there were 2 still births and 5 abortions. On the maternal side 3 haemorrhages and thromboembolic episodes which involved 2 patients on heparin, one of whom died, were observed. The following points are apparent from our observations and a review of the existing medical literature: --the risk of thromboembolism is not increased. The marked clotting tendency of maternal blood post-partum contraindicates the withdrawal of anticoagulants during this critical period; --haemorrhagic complications are common with anticoagulants; --foetal loss is greatly increased; --the teratogenecity of vitamin-K antagonists is certain, but the risk is small. The problems of anticoagulation are discussed; theoretically heparin should be given during the 1st trimestre and from the 38th week to the second post-partum week. The patients should be closely supervised by both obstetrician and cardiologist and hospitalisation is advised for the last month of pregnancy. Normal vaginal delivery is usually possible.

Abnormalities, Drug-Induced↗
PubMed1981

[Rehabilitation problems with heart valve prosthesis patients].

A vast experience of over 1500 patients with prostheses of the heart valves is being summarized. A method of physical and psychological rehabilitation of these patients is described and data are given proving the efficacy of such measures: increased physical endurance in work by 92%, decrease of psychic disorders by 41.5%. The efficacy of the sanatorium stage of post-operative treatment is shown. Not infrequently the degree of invalidity of patients with cardiac valve prostheses is exaggerated, it is stressed that the use of exercise tests by the rehabilitation commission is essential.

Ambulatory Care↗
PubMed1988

[Late thrombo-embolic complications after heart valve prosthesis].

A follow-up study of 444 patients with artificial heart valves of different makes demonstrated increased wear and thrombogenic properties of the hemispheric MKC-27 prosthesis, used in mitral position, over 5 years of follow-up. High risk of thrombo-embolic complications is related to interrupted anticoagulant treatment. Their rate could be reduced through improving the quality of anticoagulant treatment, i.e. continuous administration of anticoagulants under adequate monitoring.

Anticoagulants↗