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Results for “Heart Valve Prosthesis”

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At least 19 recordsLinked to original sources
PubMed1991

Principle of operation, design criteria and fluid dynamics of a new bileaflet heart valve prosthesis.

Bileaflet heart valves show the best fluid dynamic behaviour among mechanical valves and, as a consequence, give the best clinical results. A new bileaflet heart valve has been designed whose main characteristics are the kind of leaflet movement, low profile, fluid dynamics and material. Two flat leaflets move freely inside a very low profile housing ring. The movement is described by the rolling without sliding of the leaflet surface around a cylindrical surface on the inner wall of the housing. The opening angle is 85 degrees. Both the leaflets and the housing are machined from a solid piece of titanium and then covered with carbon by ion beam techniques. The design phase and the first fluid dynamic evaluation were done by numerical methods.

Carbon↗
PubMed1989

[Use of anticoagulants in pregnant women carrying heart valve prosthesis].

Prosthetic heart valves require permanent anticoagulant treatment. In the case of pregnancy, serious problems arise in that coumarin drugs lead to increased incidence of fetal death and malformation. On the other hand, the omission of anticoagulant treatment implies considerable risks of systemic embolism and even of maternal death. Review of the literature and the few cases published so far do not prove that antiplatelet agents are effective and safe and offer sufficient protection against thromboembolism. The use of heparin may reduce the incidence of complications. The authors come to the conclusion that women with prosthetic heart valves should be advised to avoid pregnancy. Biovalves should be applied in those who wish to bear children.

Abnormalities, Drug-Induced↗
PubMed2006

Hemolysis, high-intensity transient signals (HITS) and hemodynamic results after aortic valve replacement with the Medtronic Hall Easy-Fit heart valve prosthesis.

BACKGROUND AND AIM OF THE STUDY: Previous studies have shown a correlation between type, orientation and valve size of mechanical heart valve prostheses and the incidence of high-intensity transient signals (HITS). The study aim was to investigate the presence of HITS and hemolysis and the impact of valve size and hemodynamic parameters following aortic valve replacement (AVR) using the new Medtronic Hall Easy-Fit prosthesis. METHODS: A total of 150 patients (120 males, 30 females; mean age 62 +/- 8 years; range: 32-78 years) underwent AVR (n = 94; 63% concomitant procedures) with the Easy-Fit valve in its optimal orientation. Patients were investigated at between three and 36 months after AVR using transcranial Doppler examination of the right and left middle cerebral artery, and the incidence of HITS was determined. For evaluation of hemolysis, serum lactate dehydrogenase (LDH), hemoglobin and bilirubin were measured. These parameters were related to valve size. Transthoracic echocardiography was performed in all patients. RESULTS: Among the patients, 112 (75%) showed no or low HITS (34% none, 41% < 30/h), while only 38 (25%) had elevated HITS (range 31-100/h, 14%; range > 100/h, 11%). Statistical analysis showed a linear association between the HITS count and valve size. A positive correlation between valve size and LDH was observed; hemoglobin and bilirubin showed normal values. CONCLUSION: The valve size-dependent increase in LDH after AVR corresponds with the observation that the presence of HITS increases with valve size. In light of these findings, the surgical approach to implant the largest size Easy-Fit valve possible should be discussed, given the excellent hemodynamic results provided by the valve, even in smaller sizes.

Adult↗
PubMed1997

Midterm results with the Sorin Monostrut heart valve prosthesis.

OBJECTIVE: To monitor the hematological and clinical sequelae of a single tilting disc cardiac valve prosthesis. DESIGN: Prospective nonrandomized trial. SETTING: University teaching hospital. PARTICIPANTS: All patients receiving a single mechanical cardiac valve prosthesis were offered the Sorin Monostrut valve if they met the criteria for valve use. Seventy-five per cent of the patients entered were in New York Heart Association (NYHA) functional class III or IV. One hundred and forty-seven patients were subsequently followed at three months and then yearly after valve implantation for seven years. MAIN OUTCOME MEASURES: At one year, preoperative indexes of hemolysis were compared with three-month and one-year postoperative values. Actuarial curves for survival, freedom from cerebrovascular events and explantation were constructed for the seven-year follow-up period. RESULTS: Hemolysis, as measured by lactate dehydrogenase values, commonly occurs preoperatively, remaining significantly elevated three months and one year following valve implantation. Serum haptoglobin was normal preoperatively but was significantly low at one year. Anemia was uncommon and most patients had normal reticulocyte counts at one year. At three years, 81% of patients were in NYHA functional class I. CONCLUSIONS: Midterm results show that this valve is structurally reliable and meets all current requirements for a safe mechanical valve.

Adult↗
PubMed1992

A study of the stability of orientation in the CarboMedics bileaflet heart valve prosthesis.

A total of 25 CarboMedics bileaflet prostheses was studied in the immediate postoperative period and at 1 week, 1 month and 3 months after surgery. No evidence of rotation was found on visual comparison of valve orientation and there were no significant differences between successive studies for the distance between the septum and either the anterior (P = 0.92) or posterior leaflet (P = 1.00) of valves in the mitral position. The possibility of spontaneous rotation is a potential drawback not only of the CarboMedics prosthesis, but also of designs currently being developed. This study suggests that major rotation does not occur commonly.

Adult↗
PubMed2004

[Recurrent thrombosis of a mitral mechanical heart valve prosthesis during puerperium--a case report].

A case of a 27-year-old female with prosthetic mitral valve is presented. Prolonged anticoagulation therapy was continued during pregnancy without complications. During puerperium, the dose of subcutaneous low molecular weight heparin was reduced due to subcutaneous blood effusions. Subsequently, the patient developed acute left ventricular heart failure due to prosthetic valve thrombosis. She underwent urgent surgery with new prosthetic valve implantation. Two weeks later she suffered another episode of acute mitral prosthetic valve thrombosis which was effectively treated with intravenous heparin. Difficulties concerning prolonged anticoagulation during pregnancy and puerperium in patients with prosthetic valves are discussed.

Adult↗
PubMed1999

Recurrent endocarditis in silver-coated heart valve prosthesis.

BACKGROUND AND AIM OF THE STUDY: In order to prevent prosthetic valve endocarditis (PVE), the implantation of a new silver-coated sewing ring has been introduced to provide peri- and postoperative protection against microbial infection. METHODS: A 56-year-old woman with aortic stenosis had elective replacement with a St. Jude Medical mechanical valve fitted with a silver-coated sewing ring (Silzone). The patient developed early PVE, which necessitated reoperation after one month. Despite a second Silzone prosthesis being implanted, the endocarditis recurred. During a third operation an aortic homograft was implanted, and after six months a fourth operation was performed for a pseudoaneurysm at the base of the homograft, in proximity to the anterior mitral valve leaflet. RESULTS: The diagnosis of PVE was confirmed by the presence of continuous fever, transesophageal echocardiography and growth of penicillin-resistant Staphylococcus epidermidis from the valve prosthesis. CONCLUSION: The implantation of all prosthetic valves is encumbered with a risk of endocarditis. Although silver has bacteriostatic actions, the advantages of silver-coated prostheses in the treatment of this condition have yet to be assessed in clinical trials.

Anti-Bacterial Agents↗
PubMed1999

Concentric wear of the Delrin disc in a Bjork-Shiley heart valve prosthesis: report of two cases.

We report herein the cases of two patients who received replacement of aortic Bjork-Shiley Delrin (BSD) valves that had been implanted for over 20 years following the development of aortic regurgitation (AR) resulting from wear of a Delrin disc. Case 1 was a 61-year-old woman in whom echocardiography revealed marked left ventricular dilatation and moderate AR 23 years after an aortic valve replacement (AVR) with a 21-mm BSD valve. Case 2 was a 51-year-old woman in whom echocardiography revealed marked dilation of the right atrium and moderate AR 23 years and 8 months after an AVR with a 21-mm BSD valve, as well as a mitral valve replacement with a 3M Starr-Edwards (SE) ball valve and tricuspid annuloplasty. In both patients, the BSD valves were replaced with other mechanical valves at reoperation. Examination of the explanted BSD valves showed that the Delrin discs contained increases in the radial gaps and strut indentation grooves on the inflow and outflow surfaces. The type and magnitude of the wear on the Delrin discs in these valves were consistent with data reported in the literature for this valve design after similar implant duration.

Aortic Valve↗
PubMedDate not supplied

[Medical-surgical management of left heart valve prosthesis dysfunction due to obstruction. Eleven year's experience].

UNLABELLED: We report the surgical-medical experience in left side mechanic prosthesis cardiac valve dysfunction. From January 1986 to June 1997 we included 108 consecutive patients (pts), 24 were men and 84 women, mean age 45 years, they underwent 114 surgical procedures, 104 in mitral and 10 in aortic position. RESULTS: The dysfunction was due to obstruction in fixed disc in 107 pts and intermitent in 7 pts. The pathological findings were thrombosis in 92 pts, pannus in 9 pts and both in 13 pts. The time interval between valve replacement and dysfunction was from 1 to 247 months, mean 53.8 +/- 56.7. Seventy five percent of patients received inadequate anticoagulant therapy, the mean INR was 2.06 +/- 0.79. In 76% of patients the functional class was III or IV NYHA. The diagnosis was made by clinical and echocardiographic findings in 96% of patients. The surgical procedures included valve replacement in 103, and toilette in 11 pts. The time of extracorporeal circulation in patients who died us survival patients were (159.9 +/- 108.95 vs 87.32 +/- 27.53 min) and aortic cross-clamp (64.8 +/- 20.69 vs 48.28 +/- 23.71 min) respectively (p < 0.001). The overall mortality was 12 pts (10.5%), all in functional class III or IV NYHA (p < 0.05), five patients died during surgical procedure. In conclusion the diagnosis must be established clinically as well as by echocardiography. The risk factors associated with mortality were pulmonary edema, shock, delayed surgery, surgical time prolonged and functional class III or IV NYHA.

Anticoagulants↗
PubMed2003

Transvalvular in vivo gradients of the new generation bileaflet heart valve prosthesis St. Jude Medical Regent in aortic position.

BACKGROUND: By changing the design of the St. Jude Medical Regent prosthesis in shifting both sewing cuff and retaining ring into a completely supra-annular position, the Regent valve has a greater geometric orifice for a given outer diameter. Accordingly, in vitro studies have shown increased effective orifice areas (EOAs) and lower transvalvular gradients. The aim of our study was to determine in vivo transvalvular gradients and EOAs in patients after aortic valve replacement (AVR). METHODS: We investigated 75 patients at 12 to 21 months follow-up after AVR using transthoracic echocardiography. We determined left ventricular systolic and diastolic function, EOA, and transvalvular peak gradient parameters at rest. Outcomes were assessed using the NYHA classification and functional status. RESULTS: No patient experienced cardiac failure. The majority reported good functional status and good quality of life. Five (6.7 %) late deaths were observed within the surveillance period. At follow-up, 92 % of the patients had improved by at least one NYHA class. Transvalvular peak gradients at rest for patients with Regent valves were 25.4 +/- 7.7 mmHg, 19.2 +/- 4.6 mmHg, 15.6 +/- 5.8 mmHg, 14.6 +/- 5.5 mmHg, and 8.5 +/- 2.5 mmHg; EOAs were 1.38 +/- 0.32 cm2, 1.62 +/- 0.49 cm2, 2.24 +/- 0.83 cm2, 2.63 +/- 0.70 cm2, and 3.28 +/- 0.34 cm2 for valve sizes 19 mm, 21 mm, 23 mm, 25 mm, and 27 mm, respectively. CONCLUSIONS: The SJM Regent valve shows excellent in vivo hemodynamics as confirmed by echocardiography. Clinically, 92 % of the patients improved by at least one NYHA class.

Aortic Valve↗
PubMed1977

[Clinical anatomical basis of the pathogenesis of fatal complications in the late periods after heart valve prosthesis].

On the basis of clinico-anatomical analysis of the causes of death in 35 patients following valve prosthetics for rheumatic valvular disease, it was established that cardiac failure was the most frequent cause. Cardiac failure was due to exacerbation of the carditis process on the one hand, and to disorders of the rhythm induced by dystrophy, sclerosis, fibroelastosis, and calcinosis in the cardiac septum on the other. Thromboembolic processes rate second in frequency among the lethal complications. Death from septic complications was rarely encountered, and from causal causes only in individual cases.

Autopsy↗
PubMed1977

[Heart valve prosthesis in congenital heart defects].

The experience of 68 cases of prosthetic valve replacement for congenital heart diseases is presented. The majority of the cases were 57 patients with the Ebstein anomaly and tetralogy of Fallot. In the patients with the Ebstein anomaly the tricuspid valve was replaced, in those with the tetralogy of Fallot--a plastic enlargement of the pulmonary artery trunk and prosthetic replacement of the pulmonary valve with a ball valve or xeno-graft. Original techniques of radical correction of the Ebstein anomaly and tetralogy of Fallot are presented.

Adult↗
PubMed2004

Design and manufacture of a polyvinyl alcohol (PVA) cryogel tri-leaflet heart valve prosthesis.

Although current artificial heart valves are life sustaining medical devices, improvements are still necessary to address deficiencies. Bioprosthetic valves have a compromised fatigue life, while mechanical valves have better durability but are prone to thromboembolic complications. A novel, one-piece, tricuspid valve, consisting of leaflets, stent and sewing ring, made entirely from the hydrogel, polyvinyl alcohol cryogel (PVA-C), has been developed and demonstrated. This valve has three thin leaflets attached to a cylindrical stent. In order to approximate the complex shape of the surface of the natural heart valve leaflets, two different geometries have been proposed: revolution about an axis of a hyperboloid shape and revolution about an axis of an arc subtending (joining) two straight lines. The parameters of both geometries were examined based on a compromise between avoiding sharp curvature of leaflets and minimization of the central opening of the valve when closed. The revolution of an arc subtending two straight lines was selected as the preferred geometry since it has the benefit of a smaller central opening when the value of the maximum curvature for the leaflets is the same for each valve geometry. A cavity mold has been designed and constructed to form the PVA-C heart valve. The three leaflets were formed and integrated into the stent and sewing ring in a single process. Prototype heart valves were manufactured in the mold from a solution of PVA and water, by controlled freezing and thawing cycles.

Animals↗