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Mechanics of cryopreserved aortic and pulmonary homografts
No full textBACKGROUND AND AIM OF THE STUDY:
The surgical placement of pulmonary valve grafts into the aortic position (the Ross procedure) has been performed for three decades. Cryopreserved pulmonary valves have had mixed clinical results, however. The objectives of this study were to compare the mechanics of cryopreserved human aortic and pulmonary valve cusps and roots to determine if the pulmonary root can withstand the greater pressures of the aortic position.
METHODS:
Six aortic and six pulmonary valve roots were obtained from the Oxford Valve Bank. They were harvested during cardiac transplantation from hearts explanted for dilated cardiomyopathy (mean patient age 68 years). The whole roots were initially stored frozen at -186 degrees C, then shipped packed on dry ice. After complete thawing, the roots were pressurized whole; test strips were then cut from the valve cusps, roots and sinuses and tested for stress/strain, stress relaxation, and ultimate failure strength.
RESULTS:
The pulmonary roots were more distensible (30% versus 20% strain to lock-up) and less compliant when loaded to aortic pressures. The pulmonary valve cusp and root tissue also showed greater extensibility and greater stiffness (lower compliance) when subjected to the same loads.
CONCLUSION:
We conclude that mechanical differences between aortic and pulmonary valve tissues are minimal. The pulmonary root should withstand the forces imposed on it when placed in the aortic position. However, if implanted whole, the pulmonary root will distend about 30% more than the aortic root when subjected to aortic pressures. These geometric changes may affect valve function in the long term and should be appreciated when implanting a pulmonary valve graft
Long-term results (from 5 to 7 years) with the Hancock S-G-P bioprosthesis.
No full textThis communication is concerned with the long-term results of the first 113 patients who underwent single or multiple heart valve replacement with the Hancock-SGP bioprosthesis at the Department of Cardiovascular Surgery, University of Padova Medical School, in a two years period (March 1970-March 1972). Hospital mortality was 18.5%; of the 92 survivors, whose follow-up is now 5 to more than 7 years, the authors report the clinical reevaluation, the complications and the causes of late death. Hemodynamic reevaluation has been performed so far in 26 patients and the prostheses have shown to function properly both in the mitral and the aortic position. The data available to date indicate that the glutaraldehyde preserved porcine valve is durable and its use is warranted in any valvular position
Unexpected mechanical bileaflet valve thrombosis in mitral position: what is better to do, re-replacement or thrombolysis
No full textIF 0.92
Mitral and aortic valve replacement in valvular rheumatoid heart disease.
No full textSpecific endocarditis involving the aortic and mitral valves in a patient with peripheral rheumatoid arthritis is reported. The patient underwent prosthetic replacement of both valves. Typical rheumatoid nodules were detected histologically in the valvular tissues
Fibrous tissue overgrowth on Hancock mitral xenografts: a cause of late prosthetic stenosis.
No full textSevere prosthetic stenosis requiring reoperation seldom occurs after mitral valve replacement with the Hancock bioprosthesis. Two cases of prosthetic stenosis caused by tissue overgrowth on the atrial aspect of the cusps are reported. The patients, who had undergone mitral replacement with a Hancock valve implanted in the subannular position, developed the signs of congestive heart failure 5 and 6 years after surgery. In both patients, the hemodynamic data supported the clinical diagnosis of mitral restenosis and both underwent successful reoperation. Histologic examination showed that the pannus was formed by dense fibrous tissue with few vessels. It is suggested that the site of the bioprosthesis insertion is likely to have favored this complication since in this condition the protection of the sewing ring from tissue overgrowth is minimal
Left ventricular rupture following mitral valve replacement with a Hancock bioprosthesis.
No full textThis communication is concerned with the long-term results of the first 113 patients who underwent single or multiple heart valve replacement with the Hancock-SGP bioprosthesis at the Department of Cardiovascular Surgery, University of Padova Medical School, in a two years period (March 1970-March 1972). Hospital mortality was 18.5%; of the 92 survivors, whose follow-up is now 5 to more than 7 years, the authors report the clinical reevaluation, the complications and the causes of late death. Hemodynamic reevaluation has been performed so far in 26 patients and the prostheses have shown to function properly both in the mitral and the aortic position. The data available to date indicate that the glutaraldehyde preserved porcine valve is durable and its use is warranted in any valvular position
Rupture of the posterior wall of the left heart at the atrio-ventricular groove following mitral valve replacement.
No full textThe authors report 8 cases of left heart rupture at the insertion of the posterior leaflet of the mitral valve out of 693 mitral valve replacements. Special attention is paid to the anatomy of this area and to the technique of removal of annular calcifications, when present. In reviewing the literature, the authors analyze the cases reported up to now with particular reference to the age of patients, number of valves replaced, size and amount of calcifications, volume of the left ventricular cavity, type and size of the prosthesis employed, supra- or subannular insertion, time between valve application and rupture of the heart, techniques of repair with cardiopulmonary by-pass with a beating or arrested heart. The authors maintain that this dramatic iatrogenic complication can be avoided in most instances with some modifications of the surgical technique which has been adopted in the last 200 mitral valve replacements
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