Flow in Prosthetic Heart Valves: State-of-the-Art and Future Directions |
| |
Authors: | Email author" target="_blank">Ajit?P?YoganathanEmail author K?B?Chandran Fotis?Sotiropoulos |
| |
Institution: | (1) Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA;(2) Department of Biomedical Engineering, The University of Iowa, Iowa City, IA;(3) School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA;(4) Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA |
| |
Abstract: | Since the first successful implantation of a prosthetic heart valve four decades ago, over 50 different designs have been
developed including both mechanical and bioprosthetic valves. Today, the most widely implanted design is the mechanical bileaflet,
with over 170,000 implants worldwide each year. Several different mechanical valves are currently available and many of them
have good bulk forward flow hemodynamics, with lower transvalvular pressure drops, larger effective orifice areas, and fewer
regions of forward flow stasis than their earlier-generation counterparts such as the ball-and-cage and tilting-disc valves.
However, mechanical valve implants suffer from complications resulting from thrombus deposition and patients implanted with
these valves need to be under long-term anti-coagulant therapy. In general, blood thinners are not needed with bioprosthetic
implants, but tissue valves suffer from structural failure with, an average life-time of 10–12 years, before replacement is
needed. Flow-induced stresses on the formed elements in blood have been implicated in thrombus initiation within the mechanical
valve prostheses. Regions of stress concentration on the leaflets during the complex motion of the leaflets have been implicated
with structural failure of the leaflets with bioprosthetic valves. In vivo and in vitro experimental studies have yielded valuable information on the relationship between hemodynamic stresses and the problems
associated with the implants. More recently, Computational Fluid Dynamics (CFD) has emerged as a promising tool, which, alongside
experimentation, can yield insights of unprecedented detail into the hemodynamics of prosthetic heart valves. For CFD to realize
its full potential, however, it must rely on numerical techniques that can handle the enormous geometrical complexities of
prosthetic devices with spatial and temporal resolution sufficiently high to accurately capture all hemodynamically relevant
scales of motion. Such algorithms do not exist today and their development should be a major research priority. For CFD to
further gain the confidence of valve designers and medical practitioners it must also undergo comprehensive validation with
experimental data. Such validation requires the use of high-resolution flow measuring tools and techniques and the integration
of experimental studies with CFD modeling. |
| |
Keywords: | Prosthetic heart valves Mechanical implants Bioprosthetic implants Blood flow Computational fluid dynamics Experimental techniques |
本文献已被 PubMed SpringerLink 等数据库收录! |
|