News Column

Researchers Submit Patent Application, "Roughened Cuff Surface", for Approval

May 8, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Li, XueMei (Shoreview, MN); Alkhatib, Yousef F. (Edina, MN); Zhou, Zhengrong (Shanghai, CN), filed on March 6, 2013, was made available online on April 24, 2014.

The patent's assignee is St. Jude Medical, Cardiology Division, Inc.

News editors obtained the following quote from the background information supplied by the inventors: "The present invention relates to heart valve replacement and, in particular, to collapsible prosthetic heart valves. More particularly, the present invention relates to collapsible prosthetic heart valves with superior sealing.

"Prosthetic heart valves that are collapsible to a relatively small circumferential size can be delivered into a patient less invasively than valves that are not collapsible. For example, a collapsible valve may be delivered into a patient via a tube-like delivery apparatus such as a catheter, a trocar, a laparoscopic instrument, or the like. This collapsibility can avoid the need for a more invasive procedure such as full open-chest, open-heart surgery.

"Collapsible prosthetic heart valves typically take the form of a valve structure mounted on a stent. There are two common types of stents on which the valve structures are ordinarily mounted: a self-expanding stent and a balloon-expandable stent. To place such valves into a delivery apparatus and ultimately into a patient, the valve must first be collapsed or crimped to reduce its circumferential size.

"When a collapsed prosthetic valve has reached the desired implant site in the patient (e.g., at or near the annulus of the patient's heart valve that is to be replaced by the prosthetic valve), the prosthetic valve can be deployed or released from the delivery apparatus and re-expanded to full operating size. For balloon-expandable valves, this generally involves releasing the valve, assuring its proper location, and then expanding a balloon positioned within the valve stent. For self-expanding valves, on the other hand, the stent automatically expands as the sheath covering the valve is withdrawn. Examples of collapsible heart valves can be found in, for example, U.S. Pat. Nos. 5,411,552, 7,892,281, 8,002,825, 7,393,360, 7,914,575, 6,458,153 6,267,253, U.S. Patent Publication No. 2011/0022157 and U.S. patent application Ser. No. 11/128,826.

"Despite the various improvements that have been made to the collapsible prosthetic heart valve, common devices suffer from some shortcomings. For example, in some conventional prosthetic valves a polymeric cuff is attached to the stent. After implantation, small gaps formed between the cuff and the site of implant may cause complications such as paravalvular leakage, blood flowing through a channel between the structure of the implanted valve and cardiac tissue as a result of a lack of appropriate sealing. This leakage can have severely adverse clinical outcomes. To reduce these adverse events, a valve should seal and adequately anchor within the annulus without the need for excessive radial forces that could harm nearby anatomy or physiology.

"There therefore is a need for further improvements to collapsible prosthetic heart valves, and in particular, to cuffs of prosthetic heart valves. Among other advantages, the present invention may address one or more of these needs."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "The invention includes a cuff useful in a prosthetic heart valve which has been roughened or textured beyond any natural topography that may exist. By altering the surface topography, cell growth between the heart valve and the surrounding anatomy is promoted to assist in effectively sealing the area between the prosthetic valve and tissue. Superior sealing due to tissue growth between the valve and the anatomy allows the valve prosthetic heart valve to function as intended without the risk of paravalvular leakage for a longer period of time. Various methods and techniques are disclosed for roughening or texturing the cuff.

"In some embodiments, a prosthetic heart valve includes a collapsible and expandable stent having a proximal end, a distal end, an annulus section adjacent the proximal end and an aortic section adjacent the distal end. The heart valve further includes a cuff having an inner surface and an outer surface, the outer surface having indentations capable of providing a rough surface to promote tissue growth and a collapsible and expandable valve assembly, the valve assembly including a plurality of leaflets connected to at least one of the stent and the cuff. The cuff maybe attached to the luminal or ablumental surface of the valve.

"By 'indentation' it will be understood that any form of artificially roughened surface is contemplated such that the topography of the outer surface is no longer the same as the inner surface and is different than prior to roughening. In some examples, the indentations are uniformly distributed on the cuff. Some or substantially all of the outer surface may be roughened with indentations and the amount of roughening may vary on a single cuff. The indentations may be of any depth relative to the outer surface of the cuff and may extend partially or fully through the thickness of the cuff. The outer surface of the cuff may be rough at a microscopic or macroscopic level. In some examples, the cuff is formed of a polymer such as a polyurethane or a silicone.

"In some embodiments, a method of treating a cuff to provide indentations includes providing a collapsible and expandable stent having a proximal end, a distal end, an annulus section adjacent the proximal end and an aortic section adjacent the distal end, roughening an outer surface of a cuff to promote tissue growth between the prosthetic valve and the tissue and coupling the cuff to the collapsible and expandable stent. The cuff can also be roughened once coupled to the strut.

"Roughening an outer surface of a cuff may include forming indentations in the cuff at a macroscopic or microscopic level. Roughening an outer surface of a cuff may include using at least one needle to puncture the cuff or a thermal treatment to alter the outer surface of the cuff. A surface coating technique may also alter the outer surface of the cuff. A chemical vapor deposition technique may be used to roughen the cuff. Any other techniques capable of producing indentations are contemplated.

"In at least some examples, a gas may be used to treat the surface and generate bioactive groups or chemical structures on the cuff. The roughening step may also include immobilization of biological molecules such as growth factors onto the cuff to promote tissue growth. The roughening step may also include releasing biological molecules at a device-tissue interface to promote tissue growth.

BRIEF DESCRIPTION OF THE DRAWINGS

"Various embodiments of the presently disclosed delivery system are disclosed herein with reference to the drawings, wherein:

"FIG. 1 is a partial side elevational view of a prosthetic heart valve including a stent and a valve assembly having a cuff and leaflets;

"FIG. 2A is a perspective side view of a cuff prior to attachment to a heart valve;

"FIG. 2B is a perspective side elevational view of a cuff after the attachment portions of the cuff have been coupled together;

"FIG. 3 is a perspective side view of a cuff coupled to a stent via sutures;

"FIG. 4 is a perspective side view of a cuff coupled to a stent via sutures, the cuff having trimmed portions;

"FIG. 5 is a perspective side view of a portion of a prior art prosthetic heart valve, showing gaps formed between the valve and surrounding tissue;

"FIG. 6A is a cross-sectional view of a cuff prior to indenting and needles for indenting the cuff;

"FIG. 6B is a cross-sectional view of the cuff of FIG. 6A after the cuff has been indented using the needles;

"FIG. 6C is perspective side view of a cuff having indentations; and

"FIG. 7 is a perspective side view of a portion of a prosthetic heart valve having a cuff that has promoted tissue growth to seal the valve.

"Various embodiments of the present invention will now be described with reference to the appended drawings. It is appreciated that these drawings depict only some embodiments of the invention and are therefore not to be considered limiting of its scope."

For additional information on this patent application, see: Li, XueMei; Alkhatib, Yousef F.; Zhou, Zhengrong. Roughened Cuff Surface. Filed March 6, 2013 and posted April 24, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=1508&p=31&f=G&l=50&d=PG01&S1=20140417.PD.&OS=PD/20140417&RS=PD/20140417

Keywords for this news article include: St. Jude Medical Cardiology Division Inc.

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Source: Politics & Government Week


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