News Column

Patent Issued for Devices and Methods for Treating Valvular Regurgitation

August 18, 2014



By a News Reporter-Staff News Editor at Cardiovascular Week -- A patent by the inventors O'Beirne, Patricia (Ballybrit, IE); Rafiee, Nasser (Andover, MA), filed on December 2, 2008, was published online on August 5, 2014, according to news reporting originating from Alexandria, Virginia, by NewsRx correspondents (see also Medtronic Vascular, Inc.).

Patent number 8795352 is assigned to Medtronic Vascular, Inc. (Santa Rosa, CA).

The following quote was obtained by the news editors from the background information supplied by the inventors: "The heart is a four-chambered pump that moves blood efficiently through the vascular system. Blood enters the heart through the vena cava and flows into the right atrium. From the right atrium, blood flows through the tricuspid valve and into the right ventricle, which then contracts and forces blood through the pulmonic valve and into the lungs. Oxygenated blood returns from the lungs and enters the heart through the left atrium and passes through the mitral valve into the left ventricle. The left ventricle contracts and pumps blood through the aortic valve into the aorta and to the vascular system.

"The mitral valve consists of two leaflets (anterior and posterior) attached to a fibrous ring or annulus. In a healthy heart, the mitral valve leaflets close during contraction of the left ventricle and prevent blood from flowing back into the left atrium. Due to various cardiac diseases, however, the mitral valve annulus may become distended causing the leaflets to remain partially open during ventricular contraction and thus allow regurgitation of blood into the left atrium. This results in reduced ejection volume from the left ventricle, causing the left ventricle to compensate with a larger stroke volume. However, the increased workload eventually results in dilation and hypertrophy of the left ventricle, further enlarging and distorting the shape of the mitral valve. If left untreated, the condition may result in cardiac insufficiency, ventricular failure, and ultimately death.

"It is common medical practice to treat mitral valve regurgitation by either valve replacement or repair. Valve replacement involves an open-heart surgical procedure in which the patient's mitral valve is removed and replaced with an artificial valve. This is a complex, invasive surgical procedure with the potential for many complications and a long recovery period.

"Mitral valve repair includes a variety of procedures to repair or reshape the leaflets to improve closure of the valve during ventricular contraction. If the mitral valve annulus has become distended, a frequent repair procedure involves implanting an annuloplasty ring on the mitral valve annulus. The annuloplasty ring generally has a smaller diameter than the annulus, and when sutured to the annulus the annuloplasty ring draws the annulus into a smaller configuration, bringing the mitral valve leaflets closer together, and allowing improved closure during ventricular contraction. Annuloplasty rings may be rigid, flexible or a combination, having both rigid and flexible segments. Rigid annuloplasty rings have the disadvantage of causing the mitral valve annulus to be rigid and unable to flex in response to the contractions of the ventricle, thus inhibiting the normal, three dimensional movement of the mitral valve that is required for it to function optimally. Flexible annuloplasty rings are frequently made of Dacron.RTM. fabric and must be sewn to the annular ring with a line of sutures. This eventually leads to scar tissue formation and loss of flexibility and function of the mitral valve. Similarly, combination rings must generally be sutured in place and also cause scar tissue formation and loss of mitral valve flexibility and function.

"Another approach to treating mitral valve regurgitation requires a flexible elongated device that is inserted into the coronary sinus and adapts to the shape of the coronary sinus. The device then undergoes a change that causes it to assume a reduced radius of curvature and, as a result, causes the radius of curvature of the coronary sinus and the circumference of the mitral annulus to be reduced. While likely to be effective for modest changes in the size or shape of the mitral annulus, this device may cause significant tissue compression in patients requiring a larger change in the configuration of the mitral annulus. Alternatively, the coronary sinus in a particular individual may not wrap around the heart far enough or may not be in an optimum position to allow effective encircling of the mitral valve, making this treatment ineffective. Furthermore, leaving a device in the coronary sinus may result in formation and breaking off of thrombus that may pass into the right atrium, right ventricle, and ultimately the lungs causing a pulmonary embolism. Another disadvantage is that the coronary sinus is typically used for placement of a pacing lead, which may be precluded with the placement of the prosthesis in the coronary sinus.

"It would be desirable, therefore to provide a method and device for reducing mitral valve regurgitation that would use minimally invasive surgical techniques, but would overcome the limitations and disadvantages inherent in the devices described above."

In addition to the background information obtained for this patent, NewsRx journalists also obtained the inventors' summary information for this patent: "One aspect of the invention provides a system for treating mitral valve regurgitation comprising a delivery catheter and a tensioning device. The tensioning device comprises a plurality of helical anchors and a tension filament. The anchors are deployed from a delivery catheter such that they are implanted in the annulus of the mitral valve, and the tension filament is adjusted so that the shape of the annulus is changed in order to achieve coaption of the mitral valve leaflets.

"Another aspect of the invention provides a method for treating mitral valve regurgitation and includes preloading a tensioning device into an internal lumen of an elongated delivery catheter or delivery member. The tensioning device comprises a plurality of helical anchors, a tension filament, and at least one locking device to secure the tensioning device after the shape of a mitral valve has been changed. The method further comprises deploying the tensioning device from the catheter adjacent to the mitral valve and embedding the anchors into the annulus such that the tension filament extends through the anchors. Next, a tension force is applied to the tension filament, causing the posterior and anterior sides of the mitral valve annulus to be drawn closer to each other.

"The present invention is illustrated by the accompanying drawings of various embodiments and the detailed description given below. The drawings should not be taken to limit the invention to the specific embodiments, but are for explanation and understanding. The detailed description and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof. The drawings are not to scale. The foregoing aspects and other attendant advantages of the present invention will become more readily appreciated by the detailed description taken in conjunction with the accompanying drawings."

URL and more information on this patent, see: O'Beirne, Patricia; Rafiee, Nasser. Devices and Methods for Treating Valvular Regurgitation. U.S. Patent Number 8795352, filed December 2, 2008, and published online on August 5, 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=8795352.PN.&OS=PN/8795352RS=PN/8795352

Keywords for this news article include: Surgery, Cardiology, Annuloplasty, Medical Devices, Medtronic Vascular Inc..

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


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Source: Cardiovascular Week


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