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PubMed · 2018645

Leaflet geometry and function in porcine bioprostheses.

M Butterfield·J Fisher·G A Davies·J M Kearney
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Abstract

The leaflet geometry and hydrodynamic function of five porcine bioprostheses have been studied and compared to a fresh tissue porcine valve. The neutral leaflet geometries in two high pressure fixed valves (Carpentier Edwards and Hancock) and two low pressure fixed valves (Carpentier Edwards Supra-Annular and Hancock 2) had been modified during fixation and mounting. The leaflets were extended or displaced downwards towards the base of the valve, producing a higher ratio of circumferential leaflet length to inter-commissural spacing than in the fresh tissue valve. This produced high bending strains in the commissural area of the open leaflet in hydrodynamic tests. The leaflet geometry of the fresh tissue porcine valve studied was defined by a cylindrical shell inclined at approximately 27 degrees to the base of the valve and showed reduced open leaflet bending strains. Leaflet opening at low flows was dependent on leaflet geometry. Geometrical changes which are induced during mounting and fixation produced higher bending strains in the commissural area of the open leaflets. These may be contributing factors to tissue degeneration and calcification in this area.

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BioprosthesisHeart Valve ProsthesisHemodynamicsHumansModels, CardiovascularProsthesis DesignPulsatile FlowStructure-Activity RelationshipComparative StudyJournal ArticleResearch Support, Non-U.S. Gov't

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M Butterfield, J Fisher, G A Davies, J M Kearney. 1991. Leaflet geometry and function in porcine bioprostheses.. https://doi.org/10.1016/1010-7940(91)90079-y

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Early outcomes of tricuspid valve replacement in young children.

BACKGROUND: Early outcomes after tricuspid valve replacement in young children are ill defined. The experience of the Pediatric Cardiac Care Consortium (45 centers, 1984 to 2002) was reviewed to evaluate the results of tricuspid valve replacement in children <6 years of age. METHODS AND RESULTS: Ninety-seven patients who underwent initial tricuspid valve replacement are included in the present analysis. The most frequent cardiac diagnoses were Ebstein's anomaly (40%), pulmonary atresia (11%), and tetralogy of Fallot (8%). Age at tricuspid valve replacement was 2.9+/-1.7 years (mean+/-SD). Mean patient weight was 12.7+/-6.1 kg. The major outcome was survival to discharge. Associations among age, diagnosis, valve type/size, and outcome were evaluated through the use of chi2 analysis and logistic regression model fitting approaches. Hospital mortality was 26% and was very high (64%) in patients <1 year of age. A large size-to-weight ratio was the strongest predictor of mortality based on multivariable analysis (P<0.001). Mortality was 54% for patients with a size-to-weight ratio >2.5. Other complications included heart block requiring a pacemaker (13%) and thrombosis (5%). Pacemaker implantation was associated with the use of a mechanical valve (23% versus 6% bioprosthetic valve; P=0.01) CONCLUSIONS: Tricuspid valve replacement in young children is associated with high mortality, especially in infants <1 year of age. Surgical options other than tricuspid valve replacement such as transplantation may need to be considered in infants.

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