Conduit-mounted cardiac valve prostheses: a review of their uses, design and in vivo performance.

Although providing an historical overview of the development and clinical applications of conduit-mounted prosthetic heart valves, with elementary explanations of operative techniques, this review concentrates on the impact of design and surgical considerations on their in vivo performance. Areas showing potential for design improvement of mechanical prostheses are highlighted, both in terms of haemodynamic efficiency and haemocompatibility. Comparisons are drawn throughout the paper with conventional valve prostheses, and the key features where they differ significantly are pointed out.

A review of the in vitro evaluation of conduit-mounted cardiac valve prostheses.

This review concerns the issues affecting the in vitro evaluation of conduit-mounted prosthetic heart valves at the design development stage, and the question of standardisation of testing at the quality assurance stage. Particular attention is given to areas of conduit valve development and research which have been neglected, ambiguously covered or left to the discretion of the researcher in the current standard for conventional prosthetic valves, ISO 5840.

Theoretical evaluation of energy loss methods in the analysis of prosthetic heart valves.

The purpose of this paper is to clarify certain aspects of the 'energy loss' approach to the analysis of artificial heart valves. This involves the discussion of what is meant by 'energy loss'; the derivation of an appropriate energy equation; the scrutiny of the conditions under which it may be applied and of the assumptions involved in deriving a useful formulation in terms of readily measurable parameters; consideration of the extent to which these assumptions are valid in reported experiments using this formulation and the demonstration of the suitability and versatility of this approach when applied specifically to heart valve conduits.