News Column

Researchers Submit Patent Application, "Dialysis Valve and Method", for Approval

May 29, 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 Claude, Timothy J. (Coon Rapids, MN); Barlow, Edward A. (Bloomington, MN); Hunter, David W. (Plymouth, MN); Rosenberg, Michael S. (Eagan, MN), filed on January 13, 2014, was made available online on May 15, 2014.

The patent's assignee is INTERRAD Medical, Inc.

News editors obtained the following quote from the background information supplied by the inventors: "Dialysis involves connecting patients with insufficient kidney function to a dialysis machine which cleanses the blood of waste products and impurities. Put another way, the dialysis machine performs the same function as a normal, healthy kidney should. In other cases, dialysis is used to remove poisons and drugs from the blood more safely and quickly than the natural kidneys would. To properly connect a patient to a dialysis machine requires accessing, on a continuing basis, a blood vessel, to divert the flow of blood from the patient to the dialysis machine. This is normally accomplished by the implantation into the patient of an artificial fistula or bypass graft, which is usually made of expanded polytetrafluoroethylene (ePTFE). In the case of a graft, the graft is punctured with a needle and blood from patients requiring dialysis is transported to the dialysis machine whereupon the blood is diffused across a semipermeable membrane. Upon completion of this procedure, dialyzed blood is returned to the patient through a second needle in the graft. Dialysis is usually necessary every two to three days, which often results in the lumen of the graft becoming compromised. The more common problem related to dialysis grafts is intimal hyperplasia, which can occur when the higher pressure/volume of the arterial flow crosses the boundary from the relatively non-compliant graft to the more compliant outflow vein at the venous anastomosis. The resultant intimal hyperplasia in the vein adjacent to the anastomosis leads to progressive stenosis and eventually premature clotting and graft occlusion. Repairing a hemodialysis graft occlusion is currently accomplished by one of several techniques: open surgical revision (surgical thrombectomy), thrombolytic drugs (thrombolysis) or mechanical declotting via percutaneous techniques (percutaneous mechanical thrombectomy). Percutaneous mechanical thrombectomy techniques include suction thrombectomy, balloon thrombectomy, clot maceration and mechanical thrombectomy. The goal of each of these therapies is the preservation of vascular access. In almost all cases, any technique which is used to declot the graft will also require angioplasty of the venous anastomotic stenosis in order to reestablish normal flow.

"It is known that blood flow in excess of 300 cc per minute can cause intimal hyperplasia in the outflow vein near the anastomosis. The problem arises from the fact that blood flows less than 300 cc per minute have been associated with graft thrombosis. The solution to this dilemma appears to arise from a recognition that blood flows of less than 300 cc per minute are not intrinsically pro-thrombotic, but are a reflection of progressive stenosis that is likely to rapidly reach a level at which thrombosis can occur with any added insult. What would be ideal and what is clearly needed is a method for preventing high flows through the graft while it is not being used and thus reducing or eliminating the stimulus for intimal hyperplasia and yet allowing the high flows through the graft during dialysis that are required for a successful dialysis run."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "In one embodiment the invention comprises a method of controlling blood flow during dialysis. The method involves implanting a tube between a patient's vein and an artery, where the tube is capable of containing fluids and defines a longitudinal dimension, a diameter and an inner surface. The diameter of the tube is narrowed during dialysis at at least one location along the longitudinal dimension to control the volume and velocity of blood flow through the tube during dialysis. In another embodiment, the inner surface of the tube at the narrowed location is in a substantially circular configuration.

"In another embodiment the invention comprises a dialysis valve, the valve comprising a tube capable of containing fluids and defining a longitudinal dimension, a diameter and an inner surface. A bellows capable of being held at varying lengths defines an interior chamber wherein the tube is mounted in the chamber so that when the bellows increases in length, the tube simultaneously increases in longitudinal dimension and at least a portion of the tube decreases in diameter. In a further embodiment the tube comprises a braided nitinol structure processed to exhibit superelasticity below normal human body temperature coated with an elastomer allowing the tube to be repeatedly altered in longitudinal dimension and in diameter and still maintain fluid containing capability.

"In still another embodiment the invention comprises a dialysis valve, the valve comprising a tube capable of containing fluids and defining a longitudinal dimension, a diameter and an inner surface. A balloon contacts the tube so that when the balloon is inflated at least a portion of the tube decreases in diameter. In a further embodiment, the tube comprises a braided nitinol structure processed to exhibit superelasticity below normal human body temperature coated with an elastomer allowing the tube to be repeatedly altered in longitudinal dimension and in diameter and still maintain fluid containing capability. In yet a further embodiment the balloon surrounds the tube.

"In an alternative embodiment the invention comprises a valve, the valve comprising a tube capable of containing fluids and defining a longitudinal dimension, a diameter and an inner surface. A nitinol spring is attached to each end of the tube so that when the spring is actuated the tube decreases in longitudinal dimension and the tube increases in diameter. In a further embodiment the tube comprises a braided nitinol structure processed to exhibit superelasticity below normal human body temperature coated with an elastomer allowing the tube to be repeatedly altered in longitudinal dimension and in diameter and still maintain fluid containing capability.

BRIEF DESCRIPTION OF THE DRAWINGS

"FIG. 1 shows a side view of the uncoated braid in the truncated, open configuration.

"FIG. 1a shows an end view of the uncoated braid shown in FIG. 1.

"FIG. 2 shows a side view of the uncoated braid in the elongated, decreased diameter configuration.

"FIG. 2a shows an end view of the uncoated braid shown in FIG. 2.

"FIG. 3 shows a side view of the coated braid assembly in the shortened, increased diameter configuration.

"FIG. 3a shows an end view of the coated braid assembly shown in FIG. 3.

"FIG. 4 shows a side view of the coated braid assembly in the elongated, decreased diameter configuration.

"FIG. 4a shows an end view of the coated braid assembly shown in FIG. 4.

"FIG. 5 shows a cross section of the coated braid assembly shown in FIGS. 3, 3a, 4, and 4a.

"FIG. 6 shows a cut away plan view of the dialysis valve actuated by an elongatable/compressible bellows in the elongated, closed position.

"FIG. 6a shows a cut away plan view of the dialysis valve shown in FIG. 6 in the shortened, open position.

"FIG. 6b shows a side view of the valve shown in FIG. 6.

"FIG. 6c shows a plan view of the valve shown in FIG. 6.

"FIG. 6d shows an end view of the valve shown in FIG. 6.

"FIG. 7 shows a cut away plan view of the valve activated by an inflatable balloon.

"FIG. 7a shows a side view of the dialysis valve shown in FIG. 7, with the infusion needle penetrating the membrane.

"FIG. 8a shows a cut away side view of the valve with a nitinol coil spring in the elongated, narrowed configuration.

"FIG. 8b shows a cut away side view of the valve with a nitinol coil spring in the shortened, open configuration.

"FIG. 8c is a partial breakaway side view of the nipple and threaded member attached to the coated braid assembly.

"FIG. 9 shows a plan view of an embodiment of the valve sutured between a vein and an artery."

For additional information on this patent application, see: Claude, Timothy J.; Barlow, Edward A.; Hunter, David W.; Rosenberg, Michael S. Dialysis Valve and Method. Filed January 13, 2014 and posted May 15, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=1430&p=29&f=G&l=50&d=PG01&S1=20140508.PD.&OS=PD/20140508&RS=PD/20140508

Keywords for this news article include: Stenosis, Angiology, Hyperplasia, INTERRAD Medical Inc..

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Source: Politics & Government Week