Medtronic Hall™ Mechanical Heart Valve

• As part of the valve design, a curved, central guide strut allows the disc to move out of the annular plane, the tightest constricture of the resultant outflow tract.
• Oval (elliptical) shapes encourage laminar blood flow patterns, resulting in low thrombogenicity and contribute to the structural integrity of the valve.
• Open-ended struts are used to avoid the thrombus formation often seen in closed loop retention systems; fibrin strands are much less likely to attach to an open-ended strut.
• Pyrolytic carbon is known for its bio-compatibility, durability, and stability in the body--it doesn't change size or shape in response to the body's moisture or temperature. As proven in the Lillehei-Kaster valve, pyrolytic carbon works well with titanium. The Medtronic Hall valve disc substrate is tungsten-impregnated graphite with a pyrolytic carbon coating. The tungsten renders the disc radiopaque, enabling X-ray imaging of disc function.
• The round, flat disc is designed to maximize flow characteristics by introducing the lowest possible disturbance to natural blood flow.
• Machined from a single piece of titanium with no welds or introduced bends in valve members to weaken or otherwise compromise valve durability.
• Readily machinable, titanium polishes well, is electronegative in blood, is non-magnetic, and is both bio- and hemo-compatible. Titanium is a proven heart valve material.
• A central disc aperture allows free rotation of the disc along the central guide strut. The pivotal axis and downstream disc translation are designed to improve flow around the disc as well as through the minor orifice behind the disc, to enhance thromboresistance and improve hemodynamics.

Designed to rotate within its sewing ring to allow the surgeon to align the leading edge of the disc parallel to blood flow and to avoid interference with surrounding anatomy. Parallel blood flow enables maximum hemodynamic efficiency and reduces the amount of turbulence and stasis.

Recent aortic valve studies have shown that the Medtronic Hall valve produces lower levels of turbulence than the leading bileaflet valve. The authors determined that, "With optimum orientation ... the Medtronic Hall valve matches the aortic flow pattern to near normal physiology." Comparatively, "the St. Jude Medical valve revealed significant turbulent flow at any orientation."