Methods and apparatus for treatment of cardiac valve insufficiency
Inventors
Warnking, Reinhard • Jung, Eugene J. • Zou, Yong • Seguin, Jacques • Iyer, Mano
Assignees
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Publication Number
US-8974445-B2
Publication Date
2015-03-10
Expiration Date
Abstract
Mitral valve insufficiency is treated by introducing an expansible device such as a balloon bearing an ultrasonic transducer into the heart so that the transducer is positioned adjacent the mitral annulus but spaced from the mitral annulus, and actuating the transducer to heat the mitral annulus, denature collagen in the annulus and thereby shrink the annulus.
Core Innovation
The disclosed apparatus comprises an elongated catheter and an emitter unit positioned along its distal portion. The emitter unit includes an ultrasonic transducer surrounded by an expandable balloon with a larger proximal portion, a smaller tapered distal portion, and an abrupt change in diameter at the transition region. The transducer extends at least partially over that region and emits ultrasonic energy that causes shrinkage of the valve annulus.
When expanded within the valve, the balloon holds the transducer spaced apart from the annulus and retains the leaflets out of the ultrasonic energy path. The leaflets contact the balloon and form a seal, while the balloon does not completely occlude the annulus, permitting blood to flow through the valve. The supplied partial content does not include the background section, so the problem stated there is not explicitly described.
Claims Coverage
The supplied claims identify one independent claim, claim 1, and four dependent-claim refinements. The independent claim covers the catheter, ultrasonic emitter and balloon configuration, leaflet positioning, and continued blood flow through the valve.
Expandable balloon geometry
The expanded balloon has a proximal portion with a larger diameter than the proximal end of its distal portion, an abrupt change in diameter along the transition region, an angled distal end of the proximal portion, and a distal portion that tapers in the distal direction.
Ultrasonic transducer arrangement
The balloon surrounds the ultrasonic transducer, which extends axially at least partially over the transition region and is generally aligned with the valve annulus. Emitted ultrasonic energy causes shrinkage of the annulus.
Leaflet positioning and protection
The expanded balloon holds the transducer spaced apart from the annulus and retains the valve leaflets out of the path of the ultrasonic energy. The distal portion has a smooth outer surface to reduce the likelihood of damage to the leaflets.
Blood flow through the valve
The leaflets contact the exterior of the expanded balloon and form a seal against it. The balloon’s outer diameter is less than a cross-sectional dimension of the annulus, so the balloon does not completely occlude the annulus and blood can flow uninterruptedly between the leaflets and balloon.
Dependent-claim positioning and profile refinements
The dependent claims specify positioning the emitter unit adjacent to a posterior aspect of the annulus, a smaller cross-sectional area for the expanded distal portion than for the proximal portion, a curved outer profile of the distal portion, and a decrease in diameter at the transition region to facilitate alignment of the transducer with the annulus.
The claims cover an ultrasonic catheter apparatus whose shaped balloon positions the transducer relative to the annulus, keeps the leaflets out of the energy path, and permits blood flow through the valve. Dependent claims add emitter positioning and balloon-profile refinements.
Stated Advantages
The apparatus reduces disruption of natural blood flow through the cardiac valve by permitting uninterrupted flow while the expanded balloon is positioned within the valve.
The balloon spaces the transducer from the annulus and retains the valve leaflets out of the ultrasonic energy path.
The smooth outer surface of the distal balloon portion reduces the likelihood of damage to the valve leaflets.
Documented Applications
A catheter-based apparatus for ablating cardiac tissue and causing shrinkage of a cardiac valve annulus with ultrasonic energy while permitting blood to flow through the valve.
The supplied description specifically discusses positioning the apparatus at the mitral valve annulus to shrink annular collagen.
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