Early experience with the mosaic bioprosthesis: a new generation porcine valve.

Background: The Mosaic bioprosthesis is a new generation stented porcine valve.

Methods: Between May 1995 and April 1998, this valve was implanted in the aortic position in 98 patients (70 men; mean age, 69.2 years [34.

The medtronic intact porcine valve: ten-year clinical review.

Objective: Our objective was to assess the long-term mortality and morbidity associated with the Medtronic Intact valve (Medtronic, Inc, Minneapolis, Minn).

Method: Between 1983 and 1996, 447 patients (280 men and 167 women) received 466 Intact valves: 280 aortic, 156 mitral, and 30 tricuspid. The mean age was 57 years (median 63 years), with 45% younger than 60 years.

Long-term outcome after the mustard repair for simple transposition of the great arteries. 28-year follow-up.

Objectives: This study examines the late outcome in patients with simple transposition of the great arteries (TGA) after a Mustard operation.

Background: Continuing medical follow-up for patients after the Mustard procedure, now extending to three decades, is required. The quality of life of adult survivors has not been well documented.

Tears in bioprosthetic heart valve leaflets without calcific degeneration.

Background And Aim Of The Study: The mechanism of structural failure of bioprosthetic valves is still not clearly understood. This study was undertaken to assess pure leaflet tear as a mode of failure in porcine and pericardial bioprostheses.

Methods: Of 246 bioprosthetic valves (109 porcine, 137 pericardial) implanted between 1975 and 1991, 101 had to be explanted and served as the study population.

Mechanical properties of porcine pulmonary valve leaflets: how do they differ from aortic leaflets?

This study measured the biaxial properties of pulmonary and aortic leaflets in extension in the fresh state and then in the same samples after fixation with glutaraldehyde. The results showed that when fresh, the valves had a similar response to load in the circumferential direction, but the pulmonary leaflets were more extensible in the radial direction. They were also less stiff.

Biaxial mechanical properties of explanted aortic allograft leaflets.

The leaflets of 33 aortic allograft valves inserted using the freehand method were retrieved at reoperation, and the mechanical properties of the tissue were measured using biaxial testing methodology. Before insertion, the valves had been sterilized for 24 hours in either PSKA or CLPVA antibiotic solutions and then were either wet stored or cryopreserved. The cryopreserved valves were sterilized with CLPVA only, so there were three different treatment types in all.

Age-dependent changes in the radial stretch of human aortic valve leaflets determined by biaxial testing.

The maximum radial elastic extensibility (stretch) of human aortic valve leaflets was measured as a function of the donor age using biaxial testing techniques. The 36 leaflets tested were removed from 18 unimplanted cryopreserved aortic allograft valves retrieved from donors aged 15 to 58 years. The stretch was measured at a traction of 60 Nm-1 and analyzed as a function of the age of the donor.

Outcome of pregnancy after the Mustard operation for transposition of the great arteries with intact ventricular septum.

Objectives: This study examined the outcome of pregnancy in patients with transposition of the great arteries and an intact ventricular septum after a Mustard operation.

Background: Before the introduction of surgical treatment, most children with transposition of the great arteries died in early infancy. A number of these patients have now reached their reproductive years.

What is the best bioprosthetic operation for the small aortic root?: allograft, autograft, porcine, pericardial? Stented or unstented?

Durability is assessed with regard to valve position, patient age, and the techniques of graft preparation for each of the tissue valves. Design affects both durability and the effective orifice area. It is assessed for each of the available devices, with particular emphasis on the stentless porcine valve.

The zero pressure fixed medtronic intact porcine valve: an 8.5 year review.

The Medtronic Intact valve is the only porcine valve which is fixed in glutaraldehyde at zero pressure. This preserves near normal extensibility of the leaflet collagen, enabling full leaflet opening without kinking, which in turn should improve durability compared with low and high pressure fixed valves. From 1983 to 1991, 265 patients had 276 Intact valves inserted (125 aortic, 129 mitral, 22 tricuspid).

Aortic valve replacement in the elderly.

Aortic valve replacement is an established mode of therapy that enhances and prolongs life in patients with significant aortic valve disease. This is true for the elderly, but with a higher reported mortality and morbidity than in younger patients. One hundred and eighty-three elderly patients aged 70 years and over were considered suitable candidates for isolated aortic valve replacement (n = 97) or aortic valve replacement combined with coronary artery bypass surgery (n = 86) in the decade 1980-89.

Aortic valve replacement for active infectious endocarditis in 108 patients. A comparison of freehand allograft valves with mechanical prostheses and bioprostheses.

A total of 108 patients hospitalized with active (acute) endocarditis on either a native aortic valve (n = 66) or a previously inserted replacement device (n = 42) underwent aortic valve replacement because they were too ill for hospital discharge. A nonstented aortic allograft valve was used in 78 patients and prosthetic (mechanical or bioprosthetic) valves in 30 patients. The survival rate was 82% at 1 months, 73% at 1 year, 64% at 5 years, and 36% at 15 years.

Clinical experience with the zero-pressure-fixed Medtronic Intact bioprosthetic valve.

The Medtronic Intact porcine valve bioprosthesis was inserted in 219 patients between 1983 and 1990. Mean patient age was 52 years and mean follow up 33.3 months.

The stentless bioprosthesis: surgical challenges and implications for long-term durability.

An attempt is made to analyse the factors which are expected to influence clinical results following implantation of a stentless porcine bioprosthesis. Long experience with implantation of allograft aortic valves provides a meaningful basis for comparison with a glutaraldehyde-fixed device. Morphological differences between the two valves involve the aortic wall and muscle shelf, and differences in valve preparation include the strength and stiffness of the aorta and the extensibility of the valve leaflets.

On stress reduction in bioprosthetic heart valve leaflets by the use of a flexible stent.

It has been postulated that flexible stent posts can reduce tensile stress at the commissures of tissue heart valves by about 90% when compared with the same valve mounted on a rigid stent. We have used a detailed computer model to investigate the role of flexible stent posts in reducing stress in the leaflets of three types of bioprosthetic heart valves: the bovine pericardial and the high- and zero-pressure fixed porcine valves. The models use stress/strain data from biaxial experiments to characterize the tissue properties and are subjected to a back pressure of 120 mmHg.

Identification of a failure mode of the antibiotic sterilized aortic allograft after 10 years: implications for their long-term survival.

Freehand aortic allograft valves that had been previously sterilized with antibiotics were recovered at reoperation for biomechanical testing. The elastic extensibility of two leaflets from each explanted allograft stored in modified Hank's solution at 4 degrees C were measured using biaxial testing techniques. It was found that the leaflets had lost a significant amount of the natural, preimplant tissue extensibility.

The zero pressure fixed medtronic intact porcine valve: clinical results over a 6-year period, including serial echocardiographic assessment.

Between 1983 and 1990, 219 patients had 224 Medtronic Intact porcine valves inserted. There were 94 aortic, 110 mitral, and 20 tricuspid valve replacements. The mean patient age was 52 years.

Rest and exercise hemodynamics of 20 to 23 mm allograft, Medtronic Intact (porcine), and St. Jude Medical valves in the aortic position.

Doppler echocardiography was used to measure gradients and valve areas at rest and after supine bicycle exercise in 35 patients with valve replacements 20 to 23 mm in size. Thirteen patients with a St. Jude Medical valve (St.

Use of aortic valve allografts from hepatitis B surface antigen-positive donors.

Over a 28-month period, 31 patients undergoing aortic valve replacement received valve allografts from hepatitis B surface antigen-positive, hepatitis B e antigen-negative donors. At the time of operation, 22 recipients were immune to hepatitis B infection; 19 had antibodies to hepatitis B surface antigen, and 3 were hepatitis B surface antigen positive. Nine patients were regarded as being susceptible to hepatitis B; 7 lacked hepatitis B markers, and records of serological status could not be found for the other 2.

Early follow-up of patients with the Medtronic Intact porcine valve. A new cardiac bioprosthesis.

A new-generation porcine valve fixed in glutaraldehyde at zero pressure and mounted on an acetal copolymer flexible stent was inserted in 97 patients between August 1983 and October 1986. The mean age of the patients was 51 years (range 10 to 76) and eight were under the age of 20 years. There were 57 mitral, 33 aortic, and 10 tricuspid valve replacements.