News Column

Patent Issued for Heart Valve Replacement

July 14, 2014



By a News Reporter-Staff News Editor at Biotech Business Week -- From Alexandria, Virginia, NewsRx journalists report that a patent by the inventor Gregg, Peter W. (Santa Cruz, CA), filed on July 19, 2012, was published online on July 1, 2014 (see also Biotechnology Companies).

The patent's assignee for patent number 8764818 is Boston Scientific Scimed, Inc. (Maple Grove, MN).

News editors obtained the following quote from the background information supplied by the inventors: "Heart valve surgery can be used to repair or replace diseased heart valves. For example, heart valve replacement may be indicated when there is a narrowing of the native heart valve, commonly referred to as stenosis, or when the native valve leaks or regurgitates. Surgery to repair or replace diseased heart valves can be an open-heart procedure, conducted under general anesthesia, in which an incision is made through the patient's sternum (sternotomy), and the patient's heart is stopped while blood flow is rerouted through a heart-lung bypass machine.

"Post-surgery, patients temporarily may be confused due to emboli and other factors associated with the heart-lung machine. The first 2-3 days following surgery are spent in an intensive care unit where heart functions can be closely monitored. The average hospital stay is between 1 to 2 weeks, with several more weeks to months required for complete recovery. Given its highly invasive nature, this type of surgery is often unavailable as a treatment option for patients with compromised ability to recover."

As a supplement to the background information on this patent, NewsRx correspondents also obtained the inventor's summary information for this patent: "A prosthetic heart valve replaces the function of a native heart valve such that the prosthetic valve regulates the flow of blood through the heart.

"In one aspect, a prosthetic heart valve includes a stent and a plurality of leaflets. The stent has an outer cross-sectional area, and the stent is radially expandable to an expanded, unstressed state. Each leaflet includes a coaptation portion movable relative to respective coaptation portions of the other leaflets, an arcuate edge having a first end and a second end, the arcuate edge coupled to the stent, and a belly. The belly extends from the arcuate edge to an axis defined by the first and second ends of the arcuate edge. The ratio of the surface area of the belly to the outer cross-sectional area of the stent in the expanded, unstressed state is about 0.09 to about 0.16.

"In some embodiments, the stent in the expanded, unstressed state has an outer diameter of about 20 mm to about 30 mm.

"In certain embodiments, the arcuate edge has a radius of about 20 mm to about 50 mm and an included angle of about 35 degrees to about 70 degrees.

"In some embodiments, a maximum distance between the arcuate edge and the axis defined by the first and second ends of the arcuate edge is about 2 mm to about 4 mm.

"In certain embodiments, the arcuate edges of the respective leaflets are coupled to the stent in a plane. For example, the plane can be defined by an end of the stent.

"In some embodiments, the total arc lengths of the arcuate edges of the plurality of leaflets, as coupled to the stent, is about equal to an inner circumference of the expanded stent.

"In certain embodiments, each leaflet is substantially symmetrical about an axis of the leaflet extending in a direction from the coaptation portion to the arcuate edge.

"In some embodiments, the arcuate edge is opposite the coaptation portion. Each of the plurality of leaflets can further include first and second side portions extending from respective first and second ends of the arcuate edge toward the coaptation portion. Additionally or alternatively, the first and second side portions of each leaflet can be nonparallel to each other. For example, for each leaflet, the maximum width of the coaptation portion can be less than the maximum width of the arcuate edge.

"In some embodiments, at least one side portion of each leaflet is sutured to at least one side portion of each of the other leaflets.

"In certain embodiments, the included angle between each side portion and a tangent to a respective end of the arcuate edge is greater than about 90 degrees.

"In some embodiments, each of the plurality of leaflets has a thickness of between about 0.010 inches to about 0.015 inches.

"In certain embodiments, each of the plurality of leaflets is biological tissue. For example, the biological material is one or more of the following: bovine pericardium, equine pericardium, and porcine pericardium.

"In some embodiments, the arcuate edges of the respective plurality of leaflets are sutured to the stent.

"In certain embodiments, the stent defines a volume extending therethrough and each leaflet is disposed within the volume defined by the stent. For example, the arcuate edges of the respective plurality of leaflets can be coupled to an end portion of the stent.

"In some embodiments, the leaflets are movable between an open position permitting flow past the stent in the expanded, unstressed state and a closed position substantially restricting flow past the stent in the expanded, unstressed state.

"Embodiments can include one or more of the following advantages.

"In some embodiments, the ratio of the surface area of the belly to the outer cross-sectional area of the expanded stent is about 0.09 to about 0.16. This range of ratios can facilitate sheathing the replacement valve with a sheathing force below about 30 lbs (e.g., below about 20 lbs, below about 10 lbs) just prior to intraluminal delivery to the body passageway of the patient while also allowing the replacement valve to regulate properly the flow of blood at the implantation site in the body passageway.

"In certain embodiments, the arcuate edge that defines at least a portion of the belly of each leaflet is sutured to the expandable stent. This can allow the leaflet assembly to expand as the stent expands at the implantation site. Additionally or alternatively, suturing the arcuate edge of the leaflet to the expandable stent can reduce pressure gradients that could otherwise deteriorate the physical integrity of the leaflet over time.

"In some embodiments, the arcuate edges of the respective leaflets are coupled to the stent in a plane (e.g., a plane defined by an end of the stent). This can facilitate reliable alignment of the leaflet assembly with respect to the expandable stent and, thus, reduce the likelihood that the leaflet assembly will come into contact with the expandable stent during normal opening and closing of the replacement valve.

"In certain embodiments, the included angle between each side portion and the tangent to a respective end of the arcuate edge is greater than about 90 degrees. This can reduce the likelihood of delamination of the leaflet during preparation of the leaflet assembly and/or during use. In embodiments in which the leaflets are die cut from a flat sheet of biological material, angles greater than about 90 degrees additionally or alternatively reduce the likelihood that the die will warp over time to produce leaflets having variable sizes.

"Other features, objects, and advantages will be apparent from the description and drawings, and from the claims."

For additional information on this patent, see: Gregg, Peter W.. Heart Valve Replacement. U.S. Patent Number 8764818, filed July 19, 2012, and published online on July 1, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8764818.PN.&OS=PN/8764818RS=PN/8764818

Keywords for this news article include: Surgery, Biotechnology Companies, Boston Scientific Scimed Inc..

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


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Source: Biotech Business Week


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