Health Sciences · Temerty Faculty of Medicine
A small (~1.5 cm tall) captive disk prosthetic heart valve. The valve has a ring-like base covered in a white fabric. This disk is retained by a metal cage formed by four struts that join in a cross configuration above the disc.
Within the cage is a circular translucent plastic (HDPE) disk. The disk has a titanium ring within to make it visible under fluoroscopy.
Accession Number: 2020.med.20
Alternative Name:
Metal (CoCrMo “Stellite 21” alloy frame; titanium ring in disc), Plastic (ultra-high molecular-weight polyethylene disc); Fabric.
Markings:
Dimensions (cm): Height = 24, Max diameter = 3.2.
The Starr-Edwards model 6520 heart valve is a cardiac prosthesis that replaces a damaged or insufficient mitral valve that cannot be repaired. The valve is sutured to the heart valve annulus using the fabric sewing ring
This early caged disk mitral heart valve was designed for use in patients with left ventricles too small for the taller caged ball valve. It operates on a similar principle to caged ball valves. In this case, blood flow causes a disk to alternately descend to the ring, closing the valve, or ascend to the roof of the cage, opening it.
The fabric cover is slightly discoloured from repeated handling. The plastic disc is also slightly worn.
Associated Instruments:
Edwards Laboratories Inc. Santa Ana, California, USA.
Date of Manufacture: c. 1970s.
This artifact belongs to a small collection of items related to cardiac surgery that was collected by Dr. Wilfred Gordon “Bill” Bigelow (1913 – 2005). After his death, the collection was donated to the Cardiovascular Sciences Collaborative Program of the University of Toronto, where it is currently on display.
David J. Mehlman and Leon Resnekov (1978) “A guide to the radiographic identification of prosthetic heart valves.” Circulation 57, 3: 613-623.
Shigeaki Aoyagi, Kei-ichiro Tayama, Teiji Okazaki, Yusuke Shintani, Michitaka Kono, Kumiko Wada, Ken-ichi Kosuga, Ryusuke Mori, and Hiroyuki Tanaka (2013) “Structural valve deterioration in a Starr-Edwards mitral caged-disk valve prosthesis.” Circulation Journal 77, 1: 105-108.
Tetsuro Yokokawa, Takahiro Ohara, Seiji Takashio, Mari Sakamoto, Yuko Wada, Kenji Nakamura, Hiroyuki Takahama et al. (2016) “Prosthetic valve dysfunction 35 years after mitral valve replacement with a Starr-Edwards caged-disc valve.” Internal Medicine 55, 5: 479-483.
The Starr-Edwards artificial heart valves are named after their inventors, cardiovascular surgeon Dr. Albert Starr (1926 – 2024) and engineer Miles “Lowell” Edwards (1898 – 1982), both based in Oregon, USA.
The Starr-Edwards model 6520 was introduced in the early 1970s. As with other contemporary captive disk valves, it was intended for use in patients with left ventricles too small for a caged ball valve. It was designed to have similar performance to the Starr-Edwards model 6120 ball valve.
The 6520 notably had a thin titanium ring embedded within the disc in order to make its motion visible through fluoroscopy.
Around 3,600 examples were implanted between 1970 and 1976. The 6520 was withdrawn after only a few years. It suffered from premature wear. The design was also found to be stenotic, meaning that it restricted blood flow (Aoyagi et al. 2013, 107-108).