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Ann Thorac Surg 1998;65:235
© 1998 The Society of Thoracic Surgeons
Oxford Heart Centre, John Radcliffe Hospital, Oxford, United Kingdom;
Leiden University Hospital, Leiden, the Netherlands;
Division of Cardiovascular Surgery, The Toronto Hospital, University of Toronto, Toronto, Ontario, Canada
Accepted for publication October 30, 1997.
Mr Westaby, Oxford Heart Center, John Radcliffe Hospital, Oxford OX2 7AE, United Kingdom.
Abstract
Background. Stentless aortic xenografts are an important addition to the range of prosthetic valves. So far their use has been restricted to a limited number of study centers. This report summarizes the principal findings from the Second International Symposium on Stentless Bioprostheses. Attention is focused on the Toronto SPV and Freestyle valves recently approved by the United States Food and Drug Administration.
Methods. Stentless xenografts are used predominantly in elderly patients with aortic stenosis. Implant techniques are more complex than for stented valves, as reflected by longer ischemic and cardiopulmonary bypass times. The valves have been subjected to detailed serial echocardiographic assessment and clinical follow-up.
Results. The hemodynamic characteristics resemble those of the aortic homograft. There is a progressive increase in effective orifice area and decrease in transvalvular pressure gradients with time. Left ventricular mass index and wall thickness normalize between 6 and 12 months postoperatively. Left ventricular remodeling is accompanied by improved symptomatic status and a low incidence of valve-related complications. Limited comparative studies suggest important benefits over stented xenografts. Improved hemodynamics may translate into better bioprosthetic durability.
Conclusions. Reproducible and reliable implant methods should be taught carefully, but the hemodynamic advantages are substantial. Stentless xenografts are ideal for the elderly patient with aortic stenosis.
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