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World class computing and information science research at Strathclyde...

The Strathprints institutional repository is a digital archive of University of Strathclyde's Open Access research outputs. Strathprints provides access to thousands of Open Access research papers by University of Strathclyde researchers, including by researchers from the Department of Computer & Information Sciences involved in mathematically structured programming, similarity and metric search, computer security, software systems, combinatronics and digital health.

The Department also includes the iSchool Research Group, which performs leading research into socio-technical phenomena and topics such as information retrieval and information seeking behaviour.


The influence of prosthesis size and design on exercise dynamics after aortic valve replacement

Ali, Niaz F. and Mahadevan, Vinod S. and Muir, Andrew and Maguire, Christine and Young, David and Campalani, Gianfranco and Campbell, Norman P S and Danton, Mark H D (2006) The influence of prosthesis size and design on exercise dynamics after aortic valve replacement. Journal of Heart Valve Disease, 15 (6). pp. 755-762. ISSN 0966-8519

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Background and aim of the study: Residual gradient following aortic valve replacement (AVR) may adversely affect clinical outcome. The size and design of the valve may influence these characteristics. The study aim was to determine the influence of prosthesis physical size and leaflet design on hemodynamic performance after mechanical AVR. Methods: After AVR, two patient groups with a range of valve sizes were studied. Group 1 patients (n = 19) each received a monoleaflet valve; group 2 patients (n = 18) each received a bileaflet valve. Transthoracic echocardiography was performed at rest and after graded bicycle ergometry to assess prosthetic valve parameters, including mean and peak transvalvular gradient and effective orifice area (EOA). Results: Transprosthetic gradients (mean and peak) measured at rest, maximum exercise and 3- min recovery were related to indexed geometric orifice area (IGOA) by an exponential decay function, with no significant advantage for either valve design. However, in valve sizes ≤25 mm the bileaflet valves demonstrated lower gradients, both at rest and under exercise conditions (mean gradient during exercise, bileaflet versus monoleaflet 19.9 ± 7.2 mmHg versus 25.6 ± 6.3 mmHg, p = 0.01). Similarly, EOAs were larger in the bileaflet group when equivalent GOAs ≤2.5 cm2 were compared (EOA: bileaflet versus monoleaflet 1.51 ± 0.33 cm2 versus 1.14 ± 0.26 cm2, p = 0.018). The total work performed correlated with prosthesis diameter (r2 = 0.81, p = 0.037) and was not influenced by valve design. Conclusion: The hemodynamic performance of mechanical aortic valves, including transprosthetic gradient and maximum exercise work performed, related principally to the prosthesis physical size. However, within the smaller valve sizes, the bileaflet design appeared to offer hemodynamic advantages. © Copyright by ICR Publishers 2006.