PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “HEART VALVE PROSTHESIS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMed1980

In vivo platelet release reaction in patients with heart valve prosthesis.

Platelets play an important role in the genesis of thromboembolic episodes frequently observed in patients following cardiac valve replacement. No simple and reliable method as yet exists for quantitating platelet function in vivo. Platelet-specific proteins, serum beta-thromboglobulin related antigen and platelet factor 4 as well as thromboxane B2 were measured in 50 healthy subjects and in 100 patients who had cardiac valve replacement at least 6 months previously; these were related to the type, site and number of valves replaced. Highly significant differences were observed in the mean plasma beta-thromboglobulin related antigen, platelet factor 4 and thromboxane B2 levels in patients compared with healthy controls. The elevated levels of platelet release products observed 6 months after cardiac valve replacement suggest a continuous activation by the prosthesis. No significant differences were observed in patients with different types and site of valve prosthesis.

Adult↗
PubMedDate not supplied

[Heart valve prosthesis, anticoagulants and pregnancy].

Patients with artificial valve prostheses require lifelong anticoagulation treatment. The risk of thrombotic complications increases greatly in pregnancy. Anticoagulant treatment in pregnant women with artificial heart valve prostheses in one of the most controversial problems in medical practice as anticoagulants which are beneficial and safe for the mother may by hazardous for the fetus. Recommended procedure is to administer heparin subcutaneously at last during the first 14 weeks and the last 2 weeks of gestation and coumarin derivates throughout the second and third trimesters. In asymptomatic or mildly symptomatic women who are willing to follow a strict regimen of antithrombotic prophylaxis in pregnancy the risk is not associated with an increased morbidity or mortality in the mother or fetus. Hence, recommendations against pregnancy in women with artificial heart valves are not always justified.

Coumarins↗
PubMed1996

New polyurethane heart valve prosthesis: design, manufacture and evaluation.

In light of the thrombogenicity of mechanical valves and the limited durability of bioprosthetic valves, alternative designs and materials are being considered for prosthetic heart valves. A new tri-leaflet valve, made entirely from polyurethane, has been developed. The valve comprises three thin polyurethane leaflets (approximately 100 microns thick) suspended from the inside of a flexible polyurethane frame. The closed leaflet geometry is elliptical in the radial direction and hyperbolic in the circumferential direction. Valve leaflets are formed and integrated with their support frame in a single dip coating operation. The dipping process consistently gives rise to tolerably uniform leaflet thickness distributions. In hydrodynamic tests, the polyurethane valve exhibits pressure gradients similar to those for a bioprosthetic valve (St Jude Bioimplant), and levels of regurgitation and leakage are considerably less than those for either a bi-leaflet mechanical valve (St Jude Medical) or the bioprosthetic valve. Six out of six consecutively manufactured polyurethane valves have exceeded the equivalent of 10 years function without failure in accelerated fatigue tests. The only failure to date occurred after the equivalent of approximately 12 years cycling, and three valves have reached 527 million cycles (approximately 13 years equivalent). The simplicity of valve manufacture, combined with promising results from in vitro testing, indicate that further evaluation is warranted.

Biocompatible Materials↗
PubMed1991

[Magnetic resonance tomography in patients with a heart valve prosthesis].

Artificial valve prostheses are often regarded as a contraindication for magnetic resonance imaging (MRI), although preliminary in vitro studies suggested, that patients with these metallic implants might safely undergo MR examination. This study reports on the experience with a group of 89 patients with 100 heart valve prostheses who were examined by spin-echo MR and gradient-echo MR. MR examination was performed in all patients without complications. The spin-echo sequence showed advantages in the depiction of anatomical structures like paravalvular abscesses. Anatomical structures adjacent to the artificial valve were clearly visible and the metal components of the valves showed no or only small artifacts. Artifacts were accentuated when using gradient-echo sequences. Gradient-echo sequences provided valuable information regarding the presence of valvular insufficiency. Physiological valvular regurgitation was easy to differentiate from pathological paravalvular or transvalvular regurgitation. These results demonstrate that patients with artificial valve prostheses can be imaged by MR without risk and that prosthesis-induced artifacts do no interfere with image interpretation.

Abscess↗
PubMedDate not supplied

[Heart valve prosthesis, pregnancy and anticoagulant therapy].

The reproductive possibilities of cardiopathic patients with cardiac valvular prostheses have greatly improved in the past forty years. The correct management of this risk pregnancies remains a problem, however, especially as regards the chronic anticoagulant treatment to which these patients are subjected. The thirty years experience of a heart surgery-obstetric team is reported here. This included 14 pregnancies in women with aortic or mitral valvular prostheses. The problems relating to anticoagulant treatment in pregnancy and during labour are discussed.

Adult↗
PubMed1991

[Thrombosis of mechanical heart valve prosthesis. Value of transesophageal echocardiography in the study of mitral valve prosthesis].

Forty-three consecutive patients with mechanical valve prostheses underwent transthoracic and transoesophageal echocardiography for suspected thrombolic prosthetic valve dysfunction. The results of these investigations were compared with those of cineradiography and the clinical outcome. The diagnosis of thrombosis was retained in 11 of the 43 patients (10 mitral and 1 aortic valve prostheses). The transthoracic Doppler echo was clearly abnormal in 6 of the 11 cases. Transoesophageal echo was of essential value in all cases but one, showing abnormal movement of the mobile element and/or a paraprosthetic thrombus. The cineradiography gave false negative results in 6 cases. In conclusion, these cases underline the undeniable value of transoesophageal echocardiography in occlusive or non-occlusive thrombosis of a mitral valve prosthesis. This investigation should be undertaken whenever there is the least suspicion of thrombosis of the prosthesis.

Adult↗