Source: http://www.google.com/patents/US7762977?ie=ISO-8859-1&dq=5998925
Timestamp: 2015-04-19 09:41:18
Document Index: 743914048

Matched Legal Cases: ['Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 2007', 'Application No. 05006233']

Patent US7762977 - Device and method for vascular access - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsVascular access systems for performing hemodialysis are disclosed. The vascular access system contemplates a catheter section adapted for insertion into a vein and a graft section adapted for attachment to an artery. The catheter section may have metal or polymer wall reinforcements that allow the use...http://www.google.com/patents/US7762977?utm_source=gb-gplus-sharePatent US7762977 - Device and method for vascular accessAdvanced Patent SearchPublication numberUS7762977 B2Publication typeGrantApplication numberUS 11/216,536Publication dateJul 27, 2010Filing dateAug 31, 2005Priority dateOct 8, 2003Fee statusPaidAlso published asUS8690815, US20060064159, US20110060264Publication number11216536, 216536, US 7762977 B2, US 7762977B2, US-B2-7762977, US7762977 B2, US7762977B2InventorsChristopher H. Porter, Robert J. Ziebol, Judson A. Herrig, Laurie E. Lynch, Tuan DoanOriginal AssigneeHemosphere, Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (103), Non-Patent Citations (19), Referenced by (5), Classifications (24), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetDevice and method for vascular access
US 7762977 B2Abstract
Vascular access systems for performing hemodialysis are disclosed. The vascular access system contemplates a catheter section adapted for insertion into a vein and a graft section adapted for attachment to an artery. The catheter section may have metal or polymer wall reinforcements that allow the use of thin-walled, small outer diameter conduits for the vascular access system. One or more of the adhered, embedded or bonded conduit reinforcement structures may be removable without significant damage to the conduit sections to facilitate attachment of the sections, or to a connector between the sections. Various self-sealing materials are provided for use in the vascular access system, as well as temporary access sites and flow control/sensor systems.
providing a first and second conduit of a vascular access system;
accessing a vein at a first access site;
inserting the first conduit of the vascular access system into the vein;
forming a subcutaneous pathway between the first access site and an intermediate access site;
accessing an artery at a second access site;
attaching the second conduit to an artery through the second access site; and
positioning the first conduit and second conduit of the vascular access system in the subcutaneous pathway;
accessing an end of the first conduit and an end of the second conduit through the intermediate access site;
connecting the end of the first conduit and the end of the second conduit and reinserting the connected ends of the first conduit and the second conduit through the intermediate access site.
2. The method for treating a patient as in claim 1, further comprising providing a connector and connecting the first conduit and second conduit of the vascular access system via the connector.
3. The method for treating a patient as in claim 1, wherein positioning the first conduit and second conduit in the subcutaneous pathway comprises passing an end of the first conduit from the first access site to the intermediate access site and passing an end of the second conduit from the second access site to the intermediate access site.
4. The method for treating a patient as in claim 1, wherein positioning the first conduit and second conduit in the subcutaneous pathway comprises passing an end of the first conduit from the intermediate access site to the first access site and passing an end of the second conduit from the intermediate access site to the second access site.
5. The method for treating a patient as in claim 1, wherein positioning the first conduit and second conduit in the subcutaneous pathway comprises passing an end of the first conduit from the first access site to the intermediate access site and passing an end of the second conduit from the intermediate access site to the second access site.
6. The method for treating a patient as in claim 1, wherein positioning the first conduit and second conduit in the subcutaneous pathway comprises passing an end of the first conduit from the intermediate access site to the first access site and passing an end of the second conduit from the second access site to the intermediate access site.
7. A method for treating a patient, comprising:
providing a blood pathway having a first section and a second section, the blood pathway for conveying blood between a vein and an artery;
inserting an end portion of the first section of the blood pathway into the vein;
forming a subcutaneous pathway between the first access site and a second access site;
attaching an end portion of the second section of the blood pathway at the second access site; and
coupling the first section with the second section through an incision formed at a third access site disposed between the first and second access sites.
8. The method for treating a patient as in claim 7, further comprising closing each of the access sites such that the blood pathway is entirely subcutaneous.
9. The method for treating a patient as in claim 7, wherein coupling comprises positioning a connector between the first and second sections, wherein smooth transitions are provided at least at the junction between the first section and the connector and between the second section and the connector.
10. The method for treating a patient as in claim 9, wherein a smooth transition is provided along a change in circumference within the connector between the first and second sections.
11. The method for treating a patient as in claim 7, wherein coupling comprises positioning a connector between the first and second sections, wherein an internal lumen within the connector comprises a change in circumference within no more than one inflection point as seen in a longitudinal cross-section of the connector.
12. The method for treating a patient as in claim 7, further comprising providing a connector and inserting at least one of the first and second ends of the connector into lumens extending from ends of the first and second sections.
13. The method for treating a patient as in claim 12, further comprising causing a circumferential force to be applied through at least a portion of at least one of the first and second sections toward at least one of the first and second ends of the connector.
14. The method for treating a patient as in claim 12, further comprising advancing ends of at least one of the first and second sections over circumferential protrusions disposed on an outside surface of at least one of the first and second ends of the connector.
15. The method for treating a patient as in claim 14, wherein the protrusion comprises one or more barbs.
16. The method for treating a patient as in claim 15, wherein the circumferential compressive force is applied by applying a crimp ring to the outside of at least one of the first and second sections.
17. The method for treating a patient as in claim 12, further comprising causing a circumferential force to be applied through at least a portion of each of the first and second sections toward a corresponding one of the first and second ends of the connector.
18. The method for treating a patient as in claim 12, wherein the connector is pre-attached to the second section of the blood pathway.
19. The method for treating a patient as in claim 7, wherein the artery is a brachial artery.
20. The method for treating a patient as in claim 7, wherein the vein is a jugular vein.
21. The method for treating a patient as in claim 20, wherein the artery is a brachial artery.
22. The method for treating a patient as in claim 21, wherein the third access site is adjacent to the delto-pectoral groove.
23. The method for treating a patient as in claim 7, wherein the subcutaneous pathway is formed to minimize kinking of the blood pathway.
24. The method for treating a patient as in claim 23, wherein the subcutaneous pathway is formed to exceed a minimum bend radius to minimize kinking.
25. The method for treating a patient as in claim 7, wherein the blood pathway comprises a self-sealing area.
26. The method for treating a patient as in claim 25, wherein the self-sealing area comprises a self-sealing material.
27. The method for treating a patient as in claim 25, wherein the self-sealing area comprises a self-sealing layer.
28. The method for treating a patient as in claim 25, wherein the self-sealing area comprises an area of residual compressive stress.
29. The method for treating a patient as in claim 25, wherein the self-sealing area is elongate and flexible along its length to facilitate implantation.
30. The method for treating a patient as in claim 7, wherein the blood pathway comprises a needle access site comprising a self-sealing material or structure and further comprising positioning the needle access site subcutaneously.
The present application is a continuation-in-part of U.S. application Ser. No. 10/962,200 filed on Oct. 8, 2004, which claims priority under 35 U.S.C. �119(e) to U.S. Provisional Application No. 60/509,428 filed on Oct. 8, 2003, and to U.S. Provisional Application No. 60/605,681 filed on Aug. 31, 2004, the disclosures of which are incorporated by reference herein in their entirety.
In the United States, approximately 400,000 people have end-stage renal disease requiring chronic hemodialysis. Permanent vascular access sites for performing hemodialysis may be formed by creating an arteriovenous (AV) anastomosis whereby a vein is attached to an artery to form a high-flow shunt or fistula. A vein may be directly attached to an artery, but it may take 6 to 8 weeks before the venous section of the fistula has sufficiently matured to provide adequate blood flow for use with hemodialysis. Moreover, a direct anastomosis may not be feasible in all patients due to anatomical considerations. Other patients may require the use of artificial graft material to provide an access site between the arterial and venous vascular systems. Although many materials that have been used to create prosthetic grafts for arterial replacement have also been tried for dialysis access, expanded polytetrafluoroethylene (ePTFE) is the preferred material. The reasons for this include its ease of needle puncture and particularly low complication rates (pseudo-aneurysm, infection, and thrombosis). However, AV grafts still require time for the graft material to mature prior to use, so that a temporary access device, such as a Quinton catheter, must be inserted into a patient for hemodialysis access until the AV graft has matured. The use of temporary catheter access exposes the patient to additional risk of bleeding and infection, as well as discomfort. Also, patency rates of ePTFE access grafts are still not satisfactory, as the overall graft failure rate remains high. Sixty percent of these grafts fail yearly, usually due to stenosis at the venous end. (See Besarab, A & Samararpungavan D., �Measuring the Adequacy of Hemodialysis Access�. Curr Opin Nephrol Hypertens 5 (6) 527-531, 1996, Raju, S. �PTFE Grafts for Hemodialysis Access�. Ann Surg 206 (5), 666-673, November 1987, Koo Seen Lin, L C & Burnapp, L. �Contemporary Vascular Access Surgery for Chronic Hemodialysis�. J R Coll Surg 41, 164-169, 1996, and Kumpe, D A & Cohen, M A H �Angioplasty/Thrombolytic Treatment of Failing and Failed Hemodialysis Access Sites: Comparison with Surgical Treatment�. Prog Cardiovasc Dis 34 (4), 263-278, 1992, all herein incorporated by reference in their entirety). These failure rates are further increased in higher-risk patients, such as diabetics. These access failures result in disruption in the routine dialysis schedule and create hospital costs of over $2 billion per year. (See Sharafuddin, MJA, Kadir, S., et al. �Percutaneous Balloon-assisted aspiration thrombectomy of clotted Hemodialysis access Grafts�. J Vasc Interv Radiol 7 (2) 177-183, 1996, herein incorporated by reference in its entirety).
In one embodiment, an apparatus for providing needle access to a blood pathway is provided, comprising a graft conduit for attachment to an artery, a catheter conduit for insertion in a vein, and a self-sealing element, comprising a wall structure defining, at least in part, an internal passageway in fluid communication with said graft and catheter conduits so that, in use, said conduits and said passageway can form said blood pathway, said wall structure being formed of a tubular material that can be punctured by a needle to permit needle access to said passageway and re-seals upon withdrawal of said needle, wherein said self-sealing element may be formed a wall of the catheter conduit or located between the graft conduit and catheter conduit. The apparatus may be selected from the group consisting of material subject to compressive stress, material having a porous structure enhancing microthrombosis, low durometer materials, thixotropic materials and/or a gelatinous material. Said material may comprise at least two layers subject to compressive stress of different orientations. Said conduit connector may be pre-connected to the graft conduit at the point of manufacture. Said conduit connector may be integral with the graft conduit. The apparatus may further comprise a strain relief tube about the catheter conduit, said strain relief tube having a first end and a second end, the second end comprising two or more flexural sections and two or more separations between the flexural sections, a means for controlling blood flow rate through the blood pathway, and/or a means for monitoring blood flow rate through the blood pathway.
In one embodiment, an implantable graft for providing needle access to a blood pathway shortly after implantation is provided, said apparatus comprising an elongate, generally tubular body having a graft portion for attachment to an artery and a catheter portion having an end and being adapted for at least a section of said catheter portion to be inserted into a vein with said end distanced from the vein insertion location, a zone for repeated needle access formed of a generally tubular material which seals with respect to blood after withdrawal of the needle, said zone being formed in said catheter portion. Said catheter portion may have walls forming said tubular zone. Said zone may be an element connected between said catheter section and said graft portion. The implantable graft may comprise a connector joining said graft and catheter portions, reinforcement to reduce kinking in said graft portion, and/or reinforcement to reduce kinking in said catheter portion.
In one embodiment, an apparatus for providing needle access to a blood pathway is provided, comprising a graft conduit for attachment to an artery, a catheter conduit for insertion in a vein, and a self-sealing element, comprising a flexible wall structure defining, at least in part, a flexible internal passageway in fluid communication with said graft and catheter conduits so that, in use, said conduits and said flexible passageway can form said blood pathway, said wall structure being formed of a material that can be punctured by a needle to permit needle access to said passageway and re-seals upon withdrawal of said needle.
In one embodiment, an arteriovenous graft comprising a separate graft portion for attachment to an artery and attachable catheter portion for placement in a vein is provided, said graft portion and said catheter portion comprising a tubular structure having an internal passageway for conducting, in use, blood from said artery to said vein, and at least two lumens in fluid communication with said passageway and may further comprise a structure for interrupting said fluid communication to provide temporary access to said passageway. The means for interrupting said fluid communication may comprise a region of compressive material at the fluid communication between said tubular structure and said lumens, the compressive material biased to interrupt said fluid communication if said lumens are removed, at least one flap valve biased to interrupt the fluid communication between said tubular structure and said lumens, at least one mechanical valve biased to interrupt the fluid communication between said tubular structure and said lumens, and/or at least one lumen plug to interrupt the fluid communication between said tubular structure and said lumens. The at least one mechanical valve may be an at least one piston valve, an injectable lumen sealing compound to interrupt the fluid communication between said tubular structure and said lumens, and/or an at least one spring-biased piston valve. At least one lumen plug may be an at least one proximal lumen plug. The at least one lumen plug may be an at least one lumen plug with a locking stop. The arteriovenous graft may further comprise a connector for facilitating attachment of the catheter portion to the graft portion. The connector may be pre-connected to the graft portion, or may be integral with the graft portion. The arteriovenous graft may also further comprise a strain relief tube about the catheter portion, said strain relief tube having a first end and a second end, the second end comprising two or more flexural sections and two or more separations between the flexural sections. The arteriovenous graft may also further comprise a means for controlling blood flow rate through the internal passageway, and/or a means for monitoring blood flow rate through the internal passageway.
In one embodiment, a method for treating a patient is provided, comprising providing a first and second conduit of a vascular access system, accessing a vein at a first access site, inserting the first conduit of the vascular access system into the vein, forming a subcutaneous pathway between the first access site and an intermediate access site, accessing an artery at a second access site, attaching the second conduit to an artery through the second access site, and positioning the first conduit and second conduit of the vascular access system in the subcutaneous pathway. The method may further comprise connecting the first conduit and second conduit of the vascular access system. The positioning of the first conduit and second conduit in the subcutaneous pathway may comprise passing an end of the first conduit from the first access site to the intermediate access site and passing an end of the second conduit from the second access site to the intermediate access site. The method may further comprise connecting the end of the first conduit and the end of the second conduit and reinserting the connected ends of the first conduit and second conduit back through the intermediate access site. The positioning of the first conduit and second conduit in the subcutaneous pathway may comprise passing an end of the first conduit from the intermediate access site to the first access site and passing an end of the second conduit from the intermediate access site to the second access site, or connecting the end of the first conduit and the end of the second conduit and inserting the connected ends of the first conduit and second conduit back through the intermediate access site. The positioning of the first conduit and second conduit in the subcutaneous pathway may comprise passing an end of the first conduit from the first access site to the intermediate access site and passing an end of the second conduit from the intermediate access site to the second access site, or passing an end of the first conduit from the intermediate access site to the first access site and passing an end of the second conduit from the second access site to the intermediate access site.
In one embodiment, a method for treating a patient is provided, comprising providing a means for providing a blood pathway between a vein and an artery, accessing a vein at a first access site, inserting the means for providing a blood pathway between a vein and an artery into the vein, forming a subcutaneous pathway between the first access site and a second access site, attaching the means for providing a blood pathway between a vein and an artery at the second access site, and positioning the means for providing a blood pathway between a vein and an artery in the subcutaneous pathway.
In one embodiment of the invention, a device for treating a patient is provided, comprising a graft conduit comprising a first end, a second end, a lumen therebetween, an outer wall surface, an outer diameter, a lumen wall surface, and an inner diameter, a catheter conduit comprising a first end, a second end, a lumen therebetween, an outer wall surface, an outer diameter, and a lumen wall surface, an inner diameter, and a filament on or at least partially embedded at the outer wall surface, the filament being peelable from the outer wall surface, and a conduit connector having a first end, a second end, a lumen therebetween, wherein the first end of the conduit connector may be adapted to join the second end of the graft conduit, and the second end of the conduit connector may be adapted to joint the first end of the catheter conduit. The first end of the connector may be joined to the second end of the graft conduit. The catheter conduit may further comprise a wire reinforcement generally located between the outer wall surface and lumen wall surface and at least about the second end of the catheter conduit, a trimmable section about the first end of the catheter conduit and having an inner diameter and outer diameter, and an insertion section about the second end of the catheter conduit and having an inner diameter and outer diameter, wherein said trimmable section is adapted for implantation generally outside the vein and the insertion section is adapted for implantation generally inside the vein. The filament may be located within the trimmable section. The wire reinforcement may be a nitinol wire reinforcement. The insertion section may further comprises a wire reinforcement generally located between the outer wall surface and lumen wall surface of the catheter conduit. The catheter conduit may further comprise a wire reinforcement located within the trimmable section. The device may further comprise a means for temporary catheterization, and/or a self-sealing interface. The self-sealing interface comprises a multi-layer material wherein at least two layers of the material have different directional orientations, or a multi-layer material wherein at least one layer comprises a sealing gel between two polymeric layers.
In one embodiment, a device for treating a patient is provided, comprising a graft conduit comprising a first end, and a second end, wherein the second end comprises an elastic material, a catheter conduit comprising a first end, a second end, and a conduit connector having a first end, a second end, wherein the first end of the conduit connector may be adapted to join the second end of the graft conduit, wherein said elastic material of the graft conduit provide a snug fit with the first end of the conduit connector. The elastic material may be coated onto the second end of the graft conduit, and/or embedded into the second end of the graft conduit.
In one embodiment of the invention, a device for treating a patient is provided, comprising a catheter component with a lumen and at least one radio-opaque marker about a distal end of the catheter component, wherein the at least one radio-opaque marker comprising two or more layers of one or more radio-opaque materials having crush resilience to maintain patency of the lumen at the distal end. The at least one radio-opaque marker may be surrounded by radiolucent material.
In one embodiment, a device for treating a patient is provided, comprising a catheter component with a lumen and at least one multi-layer radio-opaque marker about a distal end of the catheter component, wherein the at least one multi-layer radio-opaque marker exhibits improved crush-resilience compared to a single-layer radio-opaque marker having the same radio-opacity to maintain patency of the lumen at the distal end
In one embodiment, an arteriovenous graft is provided, comprising a generally tubular body having an outer wall and comprising a graft section adapted for attachment to an artery, a catheter section adapted to be inserted at least partially into a vein, and a strain relief element extending around at least a portion of said tubular body and comprising a generally tubular member mounted directly or indirectly to said outer wall and having at least one end formed into two or more flexural sections by two or more slots extending inwardly from said end between said flexural sections.
Said outer wall may have an outer diameter and said tubular member may have an internal diameter at said end, said internal diameter being greater than said outer diameter. The flexural sections may be petal-shaped. The slots may comprise rounded ends. The arteriovenous graft may comprise three to six slots.
In one embodiment, a device for relieving strain on a flexible tube subject to kinking is provided, said device comprising a generally tubular body having a first end and a second end, said second end having a periphery, comprising a plurality of flexible flap elements distributed around said periphery for distributing strain. The device may further comprise three to six slots between said flexible flap elements.
In one embodiment, a device for delivering a catheter is provided, comprising a shaft comprising a proximal end, distal end and a guidewire lumen therebetween, a distal end outer diameter and a collapsible distal tip, and a catheter section comprising a first end a second end, and a catheter lumen therebetween, wherein the collapsible distal tip has an expanded configuration comprising tapered surface and a reduced configuration adapted to move within the catheter lumen. The tapered surface of the collapsible distal tip may form a generally conical shape, may comprise an expandable balloon and the shaft further comprises a balloon lumen for inflating and deflating the expandable balloon, and/or may be further configured in its expanded configuration to seal the catheter lumen at the second end of the catheter section to resist retrograde fluid flow. In some embodiments, the collapsible distal tip comprises an expandable slotted tube.
In one embodiment, a method for inserting a catheter is provided, comprising providing a catheter insert comprising an insert shaft with a guidewire lumen, and a collapsible distal tapered tip having an expanded configuration and a reduced configuration, providing a catheter having a first end a second end, and a lumen therebetween, inserting the catheter insert into the lumen of the catheter, expanding the collapsible distal tapered tip to its expanded configuration, passing the distal tapered tip of the catheter insert into a vein, positioning the catheter and catheter insert into the vein, and collapsing the collapsible distal tapered tip to its reduced configuration. In some embodiments, the method may further comprise sealing the second end of the catheter with the collapsible distal tapered tip in the expanded configuration, removing the catheter insert from the catheter lumen, and/or clamping the catheter to resist blood flow out of the catheter lumen.
In one embodiment, a device for treating a patient is provided, comprising an implantable arteriovenous graft, comprising a vein insertion end, an artery attachment end, a tubular wall and a lumen therebetween, and a flow rate control element for reversibly changing a net cross-sectional surface area of the lumen. The flow rate control element may be a compression element or a distensible fluid compartment. The distensible fluid compartment may expand to compress the blood pathway cross-sectional area by at least about 25%, at least about 50%, at least about 75%, at least about 90% or at least about 95%. The compression element may comprise a clamp structure about the lumen of the implantable arteriovenous graft conduit. The clamp structure can clamp to compress the blood pathway cross-sectional area by at least about 25%, at least about 50%, at least about 75%, at least about 90% or at least about 95%. The flow rate control element may be a contiguous secondary lumen having an expanded configuration during at least a portion of a dialysis treatment and a reduced configuration between dialysis treatments. The secondary lumen may be biased to the reduced configuration.
In one embodiment, a method for performing dialysis, comprising providing an implantable arteriovenous graft, comprising a vein insertion end, an artery attachment end, a tubular wall, a lumen therebetween, and a flow rate control element for reversibly changing net blood flow rate in the lumen, increasing the net blood flow rate during at least portion of a dialysis treatment, and reducing the net blood flow rate between dialysis treatments.
In one embodiment, a device for treating a patient is provided, comprising an implantable arteriovenous graft conduit, comprising a vein insertion end, an artery attachment end, a tubular wall and a lumen therebetween, and a flow sensor system at least partially embedded within the tubular wall. The flow sensor system may comprise a flow sensing element and an antenna, and may further comprise an external receiver. The external receiver may comprise a power supply, a transmitter, a receiving element, a signal processor and a flow readout. The flow sensor element may be a heat sensor, a pressure sensor, a magnetic sensor, a Doppler ultrasound sensor, and/or an ion sensor.
FIG. 15 is an elevational view of one embodiment of the invention comprising a multi-component vascular access system with an access region of self-sealing material.
FIG. 16 is a schematic representation of a vascular access system with a transcutaneous port.
FIG. 17 is an elevational view of a graft section with an anti-kink support.
FIGS. 18A and 18B are schematic elevation and cross-sectional views, respectively, of one embodiment of a catheter section with embedded reinforcement.
FIGS. 19A to 19C are detailed elevational views of one embodiment of a catheter section reinforced with a removably bonded filament. FIG. 19B depicts the removal of a portion of the filament from FIG. 19A. FIG. 19C illustrates the catheter section of FIGS. 19A and 19B prepared for fitting to a connector.
FIG. 20 is a schematic representation of a self-sealing conduit comprising multiple layers.
FIG. 21 is an oblique elevational view of an access port.
FIGS. 22A and 22B are elevational and cross sectional views, respectively, of one embodiment of a strain relief structure.
FIGS. 23A to 23F are schematic representations of one embodiment of the invention for implanting a two-section vascular access system.
FIGS. 24A to 24I are schematic cross-sectional views of one embodiment of a device for inserting the catheter section of the vascular access system into a blood vessel.
FIGS. 25A and 25B are schematic cross-sectional views of another embodiment of a device for inserting the catheter section of the vascular access system into a blood vessel.
FIG. 26 is a schematic representation of a vascular access system with an attached temporary catheter.
FIGS. 27A and 27B are detailed schematic representations of vascular access system coupled to a temporary catheter using a compressive interface.
FIGS. 28A and 28B are schematic cross-sectional views of a conduit connector with a pair of mechanical valves for attaching a temporary catheter in the open and closed configurations, respectively.
FIGS. 29A to 29C are schematic representations of a temporary catheter with a full-length plug.
FIGS. 30A to 30C are schematic representations of a locking temporary catheter used with a proximal plug and catheter cutter.
FIGS. 31A to 31D are schematic longitudinal and axial cross-sectional views of one embodiment of the invention comprising a dual-compartment flow control section of a vascular access system in high-flow and low-flow states, respectively.
FIGS. 32A and 32B are schematic axial cross-sectional views of another embodiment of the invention comprising a dual-compartment flow control section of a vascular access system in high-flow and low-flow states, respectively.
FIG. 33 is a schematic view of one embodiment of the invention comprising a flow sensor assembly.
FIGS. 34A and 34B are oblique elevational views of one embodiment of the invention comprising a crimping tool for securing portions of the vascular access system to a connector.
FIG. 35A depicts one embodiment of the invention comprising length markers and a crush-resilient radio-opaque marker. FIG. 35B is a cross-sectional view of the crush-resilient radio-opaque marker.
FIG. 36 is a cross-sectional view of a connector with biased flaps for providing access to the blood passageway.
FIGS. 37A to 37E are schematic representations of another embodiment of the invention for implanting a two-section vascular access system.
Research indicates that graft failures from localized stenosis at the venous end of AV grafts are primarily due to intimal hyperplasia, compliance mismatch between the graft and the native vein anastomosis, and turbulent flow at the anastomosis site. Kanterman R. Y. et al �Dialysis access grafts: Anatomic location of venous stenosis and results of angioplasty.� Radiology 195: 135-139, 1995. We hypothesize that these causes could be circumvented by eliminating the venous anastomosis and instead, using a catheter to discharge the blood directly into the venous system. We have developed vascular access system that eliminates the venous anastomosis in the AV shunt, using a catheter element at the venous end and a synthetic graft element anastomosed to the artery in the standard fashion. We believe that such system should eliminate or reduce venous hyperplasia, which is the largest reason for AV shunt failure.
A. Vascular Access System
The interfaces where separate components are joined or attached, however, are potential sources of turbulent flow along the blood flow path of the device. Sharp indentations or protrusions of the lumen will cause alterations in flow at the interface that may result in hemolysis and clot formation. Such an interface may create an increased risk of creep or separation of joined components over time that can worsen the flow characteristics at the interfaces or even result in loss of flow, respectively. Thus, the connector system used to attach the various components may benefit from one or more design features that maintain smooth flow between components through the interface and also resist creep or separation of the joined components. Such a connector system may be used with AV grafts, peripherally inserted central catheters (PICC), implantable infusion catheters with and without fluid reservoirs, implantable infusion pumps, left ventricular assist devices, and any other device where providing laminar flow between two body fluid conduits may be beneficial. For example, such a connector may be used to join an arterial graft and a venous catheter as described by Squitieri in U.S. Pat. Nos. 6,102,884 and 6,582,409, and by Porter in U.S. Provisional Application No. 60/509,428, herein incorporated by reference in their entirety. In addition to joining tubular conduits, the connector may also be used to join conduit or reservoir containing devices such as needle access ports as described by Porter in U.S. Provisional Application No. 60/605,681, herein incorporated by reference in their entirety. The connectors may also be integrated with such conduit or reservoir containing devices.
In one embodiment of the invention, a connection system for attaching a catheter to a graft in an AV hemodialysis shunt is provided. The connection system may comprise a biocompatible and/or hemocompatible material. The connection system may also provide for the attaching of a graft and a catheter having different internal and/or outer diameters. In some embodiments of the invention, the connection system provides a lumen with a smooth fluid path from one end of the connection system to the other. The smooth fluid path may reduce the risk of clot formation and hemolysis of red blood cells. The connector system may also have a securing system for resisting disconnection of the joined components. An anti-kink system may also be provided to resist occlusion along portions of the catheter and/or graft. An anti-kink system may be advantageous for an AV graft comprising PTFE or a catheter comprising silicone or polyurethane, which may be prone to bending and/or twisting. It may also be advantageous to preconnect one element to the connector before the start of surgery which then makes the procedure easier to perform in the operating room and it may also reduce the chance of error.
FIGS. 1B and 1C depict one embodiment of the invention comprising a reduced thickness of the connector wall t′, t″ at the edges 26, 28 of the connector 2. The reduced connector wall thicknesses t′, t″ allows the lumen 10 of the connector 2 to remain generally flush or nearly flush with the lumens of the conduits joined at each end 4,8. In some embodiments, the connector wall thicknesses are configured to reduce t′ and t″ sufficiently to decrease the flow disturbance in the lumen while having an edge profile shaped in such a way that reduces the risk of cutting the lumens of the tubing or pose a hazard to the surgeon. In one embodiment, the connector wall thicknesses are optimized to reduce t′ and t″ as small as possible to prevent flow disturbance in the lumen while having an edge profile shaped in such a way that it does not cut the lumens of the tubing or pose a hazard to the surgeon. For some embodiments, the thickness of the connector wall t′, t″ may be determined at a measurement point in the lumen about 0.5 mm or 1.0 mm from the lumen opening. The measurement point of the thickness t′, t″ of the connector wall may also be defined at the inflection point 30, 32 where the connector edge 26, 28 joins the linear lumen wall as identified on a longitudinal cross section of the connector 2. Where the connector edges 26, 28 are rounded or smoothed, the inflection points are where the curves of the edges 26, 28 meet the linear lumen wall edges as defined on a longitudinal cross section of the connector 2. In some embodiments of the invention, the connector edges 26, 28 at the ends 4, 8 of the connector 2 generally have a thickness t′, t″ no greater than about 20% of the inner diameter of the lumen d′, d″ at the most proximal portion 16 and most distal portion 18 of the lumen 10, respectively. In some instances, the thickness of at least one connector edge t′, t″ is less than about 10% of the inner diameter d′, d″ of the lumen 10 at one connector edge, respectively, and in still other circumstances, the thickness t′, t″ is preferably less than about 5% or about 3% of the inner diameter d′, d″ of the lumen 10, respectively. The connector wall thickness t′, t″ may also be defined relative to the outer diameter od′, od″ of the connector 2 at the same measurement point. Thus, the connector wall thickness t′, t″ may be no greater than about 20% of the outer diameter od′, od″ of the connector 2, respectively, and in some instances no greater than about 10% of the outer diameter od′, od″ of the connector 2, respectively, and preferably less than about 5%, about 3% or about 1% of the outer diameter od′, od″ of the connector 2 at the measurement point, respectively.
In one embodiment, the connector 2 has a length of about 10 mm to about 50 mm, and preferably about 15 mm to about 30 mm and more preferably about 20 mm to about 25 mm. The connector may comprise any of a variety of biocompatible materials, such as titanium or a titanium alloy, nickel or a nickel alloy, MP35N, stainless steel, polysulfone, PEEK, nylon, polypropylene or polyethylene or any flexible or chip-resistant polymer. All or a portion of the outer and/or inner surface of a metallic connector may be passivated or anodized. All or a portion of the outer and/or inner surface of the connector may be coated or insert molded with silicone or other hemocompatible material to provide a lubricious characteristic or to augment other properties of the connector, such as corrosiveness and/or clot formation. The connector may further comprise a drug eluting surface capable of eluting a therapeutic agent that can reduce the risk of infection, clot formation or affect tissue growth about the connector 2.
B. Improvements to Vascular Access System
In the one embodiment of the invention, depicted in FIG. 15, the vascular access system (VAS) 100 comprises a first section 102 of graft material with an integrated connector end 104 attachable to a second section 106 comprising a catheter component that is adapted to transport the blood and also to be inserted into the venous system using a venotomy or even less-invasive procedure. The second section 106 may have a small diameter of about 7 mm or less, preferably about 6 mm or less, and most preferably about 5 mm or less so it does not require a large venotomy to implant the second section 106 and whereby the second section 106 does not occupy an excessive amount of space in the venous system. The VAS 100 preferably has thin walls to maximize the area available to flow through the VAS 100, which may be achieved using reinforced thin-wall tubing. The second section 106 has an opening adapted to be within the vein itself and wherein the opening is distant or is located downstream from the insertion site where the second section 106 inserts into the vein. The portion of the second section 106 insertable into the vein has an outer diameter which is less than an inner diameter of the vein in which it is disposed such that, in operation, blood can flow through the second section into the vein and also through the vein itself around the outer surface of the second section 106. The second section 106 may be adapted to be entirely subcutaneous in use and configured to avoid, in use, a blood reservoir therein and to provide continuous blood flow. The selection of the diameter and length of the two sections 102, 106 may be determined by assessing the vein in which the VAS 100 is to be inserted, the insertion length of the second section 106, and/or possibly the flow rate and pressure drop criteria needed to perform hemodialysis.
The second section 106 may be trimmed and then attached to the graft section 102 to achieve the desired total length. The graft and catheter sections 102, 106 are made to resist kinking and crushing, yet not be excessively stiff. In one embodiment of the invention, these properties may be provided by a spiral reinforcement 108 in a silicone tubing 110. Other materials that may be used include PTFE, polyurethane and other hemocompatible polymers. Also shown in FIG. 15 is a section of the catheter element 106 comprising a self-sealing area 112 that provides access by needles to perform dialysis either temporarily while the graft 102 is healing in or on a long-term basis. The self-sealing area 112 is preferably self-supported (e.g. frameless), generally having the same diameter and shape as the catheter and/or graft sections of the VAS, generally having a tubular configuration so that is may be punctured at any point along its length and/or circumference. The self-sealing area 112 may comprise a self-sealing material that forms a layer of the wall of at least a portion of the graft and/or catheter section of the VAS. Unlike self-sealing material provided in an access port, the self-sealing area 112 remains flexible along its length or longitudinal axis to facilitate implantation of the VAS and also to provide a longer self-sealing area 112 than can be provided by a self-sealing region on a bulky access port. The longer length allows the insertion of dialysis needles within a larger surface area so that the same small skin region need not be repeatedly pierced and thereby significantly reducing the chance of forming a sinus tract, which could lead to infection and/or bleeding. This also allows a given needle tract more time to recover between needle piercings, and therefore may further reduce the risk of infection and/or bleeding compared to traditional access ports. In one embodiment, the self-sealing area 112 has a length of at least about 2 inches, in other embodiments at least about 3 inches, and in still other embodiments, at least about 4 inches or 5 inches. The VAS may also optionally comprise a flow sensor that is imbedded in the wall of the VAS which can be interrogated externally to give a reading of flow in the device, and/or a section of tubing that can be adjusted post implant to control flow. These and other features are described in greater detail below.
Other access sites may be provided using one or more other components, structures or materials, including the use a puncture-resistant, circumferentially compressed tubing material in a portion of or all of the catheter section, a gel material sandwiched within the walls of the tubing, a low durometer material, a needle-accessible graft section or any combination thereof, an implantable port than can be accessed by needles, and/or a transcutaneous port 114 accessible without piercing the skin 116, as depicted in FIG. 16. Some of these features are discussed in greater detail below.
In some embodiments of the invention, the graft and/or catheter sections may also be coated with one or more therapeutic agents to address any of a variety of VAS-related effects, including but not limited to resisting thrombosis, reducing infection, speeding up healing time, promoting cell growth and/or improving arterial anastomosis. These agents include but are not limited to heparin, carbon, silver compounds, collagen, antibiotics, and anti-restenotic agents such as rapamycin or paclitaxel. These agents may be bonded to a surface of the VAS, as is known in the art, with heparin and chlorhexidine-bonded materials, or these agents may be eluted from a drug-eluting polymer coating.
Similarly, the porosity and other characteristics of the self-sealing area 112 may also be altered to augment its effects. For example, this can be done by varying the porosity, construction and wall thickness of the conduit material. Some commonly used materials are ePTFE, polyurethane, silicone or combinations of these materials manufactured in such a way as to render the outer wall surface of the conduit porous. The porous nature facilitates tissue in-growth, which can help to reduce infection rates. It is believed that a porosity of about 20 μm or less in a material provides leak-resistance of the bulk material before needle puncture. Therefore it is preferred but not required that at least a portion of the wall thickness be constructed of a material with a porosity of about 20 μm or less. However, porosities of about 10 μm to about 1000 μm or more on the outer surface may facilitate cellular ingrowth into a porous surface that will reduce serous fluid accumulation surrounding the implant, which in turn reduces the infection rate associated with needle puncture. More preferably, porosities of about 20 μm to about 200 μm, and most preferably about 100 μm to about 200 μm are used. To provide a material that is leak-resistant and has improved cellular ingrowth, a multi-layer material may be provided, with a surface layer having a porosity and/or or other features for facilitating cellular ingrowth, and a subsurface material with features for facilitating leak-resistance. However, that cellular-ingrowth may also be achieved with smooth-surface devices through the use of various substrates or therapeutic agents coated onto the graft and/or catheter section. Furthermore, in regions of the VAS not intended for needle puncture, those regions may be provided with a porous layer or coating to facilitate tissue ingrowth without requiring a leak-resistant sub-layer. These materials are also biocompatible and may be manufactured, for example, so that they have a comparable compliance to the arteries to which they are attached to facilitate the creation and patency of the arterial anastomosis. The inner and outer surfaces of the conduit may also be of different materials, surface structure, and possess coatings to enhance reactions with the body such as patency, infection resistance, and tissue ingrowth.
1. Graft Section
As previously mentioned, the graft section of the vascular access system may comprise ePTFE, polyurethane, silicone, Dacron� or other similar material. The graft section 102 of the VAS 100 may have a length of at least about 20 cm, preferably greater than about 40 cm, and most preferably greater than about 60 cm. The graft section 102 may have an inside diameter within the range of from about 5.5 mm to about 6.5 mm, and sometimes about 5 mm to about 7 mm. The wall thickness of the graft section 102 may be about 0.3 mm to about 2 mm, sometimes about 0.4 mm to about 1 mm, and preferably about 0.5 mm to about 0.8 mm.
As mentioned previously, strain relief is provided in some embodiments of the invention. Strain relief may be advantageous for conduits or grafts that comprise PTFE or other flexible materials and may prevent occlusion of the conduit or graft. In some embodiments, such as those illustrated in FIGS. 4 to 10, the strain relief structure typically comprises a flexible spiral or coil that extends from an end of the connector 2 or connector sleeve 44 and onto the outer surface of or within the wall of the conduit/graft 12. The strain relief structure may comprise a biocompatible metal or plastic.
In an alternate embodiment of the invention, rather than providing a strain relief structure projecting from the connector or connector sleeve onto the graft section, the strain relief structure may be attached directly to the graft section. In one particular embodiment depicted in FIG. 17, the graft section 102 comprises ePTFE material 118 with a PTFE spiral strain relief structure 120 generally located at the connector end 119 of the graft section 102 that is attached or attachable to the catheter section 106 or conduit connector 122 of the vascular access system (VAS) 100. The embodiment depicted in FIG. 17 is a spiral strain relief structure 120, but one of ordinary skill in the art will understand that other strain relief structures may also be attached to the graft section 102. In some instances, the spiral PTFE support is configured to terminate generally at the connector end of the graft section, while in other embodiments, the spiral strain relief structure may extend beyond the end of the graft section to contact the connector or connector sleeve. In other embodiments, the spiral PTFE support is spaced within about 0.2 cm from the connector end 119 of the graft section 102. The spiral PTFE support may have a length of about 1 cm to about 8 cm, preferably about 2 cm to about 6 cm, and most preferably about 2 cm to about 4 cm. The spiral PTFE support may be staked (cold, heat, thermal, and/or ultrasonic) to the PTFE graft material, bonded to the graft material using an adhesive, or held in place by a coating on the graft section 102.
In another embodiment, the graft material is coated and/or embedded with silicone or other elastic material in the region near the connector to improve contact of the wall of the graft with the connector when graft is subjected to bending. This may be beneficial because the ePTFE graft material is naturally plastically deformable and, when it is subjected to a bend at the end of the connector, it may open up a gap that will disrupt blood flow (causing turbulence and pooling) and result in clot formation. The addition of elastic material may help maintain a tighter fit between the graft and connector surface. In one preferred embodiment, the graft is spray or dip coated using a silicone-xylene blend having a viscosity of approximately 200 cps. The viscosity may range from about 50 to about 1000 cps, more preferably about 100 to about 300 cps, and most preferably from about 150 to about 250 cps. Alternatives include low viscosity silicones, urethanes, styrenic block copolymers or other elastomers without solvents or with xylenes, toluenes, napthas, ketones, THF or other suitable miscible solvents.
The graft section of the VAS may optionally have length markers on its surface to facilitate trimming of the graft section to a desired length for individualizing the device to a particular patient's anatomy. The length markers or other markers provided in the graft section may also be radio-opaque to facilitate radiographic visualization of the graft section.
2. Catheter Section
As previously mentioned, the catheter section of the VAS may comprise a conduit having a non-uniform diameter. The end of the catheter section adapted for insertion into a vein or other blood vessel may have an inside diameter of about 3 mm to about 10 mm, sometimes within the range of about 4 mm to about 6 mm, and preferably about 5 mm, and may have an embedded or external spiral support to provide kink resistance. The end of the catheter section adapted for attachment to a connector or graft section may have a larger diameter because it does not reside within the lumen of a blood vessel. The selection of the inner diameter, outer diameter and length of the catheter section may be selected by one skilled in the art, based upon factors including but not limited to the vein into which the second body fluid segment is being inserted into, the length of catheter to be inserted through the vein wall, as well as the desired flow rate and fluid resistance characteristics.
The catheter section typically comprises PTFE, polyurethane or silicone. Other biocompatible materials that may be used include polyethylene, homopolymers and copolymers of vinyl acetate such as ethylene vinyl acetate copolymer, polyvinylchlorides, homopolymers and copolymers of acrylates such as polymethylmethacrylate, polyethylmethacrylate, polymethacrylate, ethylene glycol dimethacrylate, ethylene dimethacrylate and hydroxymethyl methacrylate, polyurethanes, polyvinylpyrrolidone, 2-pyrrolidone, polyacrylonitrile butadiene, polycarbonates, polyamides, fluoropolymers such as homopolymers and copolymers of polytetrafluoroethylene and polyvinyl fluoride, polystyrenes, homopolymers and copolymers of styrene acrylonitrile, cellulose acetate, homopolymers and copolymers of acrylonitrile butadiene styrene, polymethylpentene, polysulfones, polyesters, polyimides, polyisobutylene, polymethylstyrene, biocompatible elastomers such as medical grade silicone rubbers, polyvinyl chloride elastomers, polyolefin homopolymeric and copolymeric elastomers, styrene-butadiene copolymers, urethane-based elastomers, and natural rubber or other synthetic rubbers, and other similar compounds known to those of ordinary skilled in the art. See Polymer Handbook, Fourth Edition, Ed. By J. Brandup, E. H. Immergut, E. A. Grulke and D. Bloch, Wiley-Interscience, NY, Feb. 22, 1999.
Preferably the portion of the catheter section that is insertable into the vein is sized to allow collateral flow of blood around the inserted catheter and through the vascular site where the catheter section is inserted. It is also preferred in some embodiments that the catheter section of the VAS be dimensioned to allow percutaneous insertion of the catheter section into a vein using the Seldinger technique, rather than by venous cutdown or full surgical exposure of the vein. Percutaneous insertion of the catheter section into a vein, such as an internal jugular vein, for example, is facilitated by a catheter section having an outer diameter of no greater than about 6 mm, and preferably no greater than about 5 mm or about 4 mm.
In one embodiment of the invention, the catheter section of the VAS is reinforced with polymeric filament, metallic wire or fibers, or combination thereof, and preferably in a spiral configuration. Reinforcement of the insertion segment of the VAS, especially with metallic wire or fibers, may be used to provide an insertion segment with a reduced outer diameter and one that has improved anti-kink and/or crush-resistant properties compared to a similar catheter section lacking reinforcement. The wire or line may be bonded to the outer or inner surface of the catheter section, or may be extruded with or molded into the silastic material to form the catheter section. In some embodiments, a spiral wire is placed or bonded to the outer surface of a conduit material and then spray or dip coated with a material to provide a smooth outer surface that is not interrupted by the wire reinforcement. One of skill in the art will understand that other reinforcement configurations besides a spiral configuration may be used, including discrete or interconnected rings, circumferential and/or longitudinal fibers that may be aligned, staggered or randomly positioned in or on the walls of the VAS.
In one example, the catheter section comprises a silicone extruded tube with a nylon winding for reinforcement. The silicone may contain from about 1% barium to about 30% barium to improve the radio-opacity of the catheter section. In other embodiments, the silicone may contain from about 5% to about 20% barium, and in still other embodiments, the silicone may contain from about 10% to about 15% barium. Other radio-opaque materials may be substituted for barium or used in addition to barium. The nylon winding may comprise a nylon monofilament with a diameter of about 0.005 inch diameter to about 0.050 inch diameter, and preferably about 0.010 inch to about 0.025 inch diameter. The winding may be configured for a wrap of about 10 to about 60 per inch, preferably about 20 to about 40 per inch. Silicone over molding, step up molding and/or silicone spray may also be used to provide a more consistent and/or smoother outer diameter over the portions of the catheter section.
In another example illustrated in FIGS. 18A and 18B, the catheter section 106 comprises a silicone tube 124 with Nitinol winding 126 for reinforcement. The Nitinol winding 126 may have a diameter of about 0.002 inch diameter to about 0.020 inch diameter, and preferably about 0.003 inch diameter to about 012 inch diameter. The Nitinol winding 126 may be configured for a wrap of about 10 to about 100 per inch, and preferably about 20 to about 60 per inch. The outer surface of the catheter section 106 is sprayed with silicone 128 to provide a more uniform and smoother outer diameter.
It is well known to one skilled in the art that a radio-opaque marker band may be placed at the distal end of the catheter to improve the surgeon's ability to place the catheter tip at a desired location. However, current marker bands are made of a solid ring/band of radio-opaque material, such as platinum or gold, which may become permanently deformed if it is inadvertently compressed or squished. Referring to FIG. 35B, to improve the crush resilience of the marker band, the marker band 300 may be composed of two or more bands 302 or loops of metal stacked or layered on top of each other until a total material thickness is reached that achieves the desired radio-opacity.
For instance, two or more layers of a flat (thin and wide) ribbon may be wrapped on the tip of a catheter to produce the desired radio-opacity. The reason the crush resilience is improved is that the amount of flex that a material can withstand before it becomes permanently deformed is proportional to the thickness (because the material strain is proportional to thickness). For instance, by halving the thickness, the amount of flex is doubled before permanent deformation occurs. It is preferred that the individual layers should not be substantially adhered to one another; otherwise the effective thickness will be increased and the crush-resilience may be diminished. Thus, in the preferred embodiment, a minimum of two layers of 90% platinum/10% iridium ribbon wire are embedded within the tip of the catheter. The wire dimension is preferably about 0.0005 to about 0.001 inch thick by about 0.003 to about 0.010 inch wide. However other dimensions may also be used.
In one specific embodiment, the catheter section of the VAS comprises an insertion segment reinforced with spiral Nitinol wire, and a connecting segment reinforced with polymeric spiral filament. The insertion segment of the catheter section is adapted to be inserted into a vein while the connecting segment is adapted for attachment to a conduit connector and/or to the graft section of the VAS. By using metal wire for the insertion segment of the catheter section, smaller outer diameters may be achieved to facilitate insertion of the catheter section of the VAS through the skin and into a vein or other blood vessel. On the other hand, by providing polymeric reinforcement of the connecting segment, the diameter of the connecting segment may be reduced while maintaining the ability to trim the connecting segment of the catheter section without creating a sharp end or burr that may result when cutting through a metal wire reinforced portion of the catheter section. The insertion segment may have a length of about 10 cm to about 50 cm, preferably about 15 cm to about 35 cm, and most preferably about 20 cm to about 25 cm. The connecting segment of the catheter section can have a pre-trimmed length of about 10 cm to about 50 cm, preferably about 15 cm to about 35 cm, and most preferably about 20 cm to about 25 cm. In some embodiments of the invention, the total length of the catheter section is about 20 cm to about 250 cm, sometimes about 30 cm to about 60 cm, and other times about 120 cm to about 250 cm. Longer lengths may be used when implanting the device between axillary/femoral sites.
In further embodiments of the invention, depicted in FIG. 19A, the polymeric reinforcement 130 of the catheter section 106 is bonded or adhered to the outer surface 132 of the connecting segment 134, rather than embedded within the wall of the connecting segment 134. In some embodiments, such as those in FIGS. 19A and 19B, the polymeric reinforcement 130 is also bonded or adhered in a manner that allows the controlled peeling or separation of a portion of the polymeric reinforcement 130 from the outer surface 132 of the connecting segment 134, without damaging or violating the integrity of the remaining structure of the connecting segment 134. Referring to FIG. 19C, this feature may be beneficial in embodiments of the invention where the polymeric spiral reinforcement 134 resists or prevents the radial expansion of the connecting end 136 needed in order to fit the end of the connecting end 136 over a conduit connector 122. By allowing the controlled removal of a portion of the polymeric reinforcement 130, after trimming the connecting segment 134 of the catheter section 106 to its the desired length, a portion 136 of the polymeric reinforcement 130 may be removed from the connecting segment 124 in order to prepare the catheter section 106 for fitting to a conduit connector 122 or an integrated connector on a graft section of a VAS. In a similar fashion, the reinforcement may preferably be embedded in the catheter wall but close to the outer surface to enable easy removal.
To reduce the risk of damage to the catheter section and/or blood vessel structures where the catheter section is inserted, and/or to reduce the turbulent blood flow at the distal opening of the catheter section, the edge of the distal tip of the catheter section may be rounded. In some embodiments, rounding may be performed with a silicone dip or shadow spray, or may be molded to a round shape.
Referring to FIG. 35A, as with the graft section of the VAS, the catheter section 106 may optionally have length markers 298 on its surface to facilitate trimming of the catheter section 106 to a desired length for individualizing the device to a particular patient's anatomy. The length markers or other markers provided in the catheter section may also be radio-opaque to facilitate radiographic visualization of the catheter section. Likewise, the catheter section may be coated with one or more therapeutic agents to treat any of a variety of VAS related effects, including but not limited to resisting thrombosis and/or reducing infection.
3. Improved Strain Relief
As described above, the catheter and/or graft sections of the VAS may be provided with strain relief support to prevent or resist kinking that may occur around their connections with the conduit connector.
The use of a tapered strain relief to prevent kinking when a flexible tube or cable is connected to a rigid connector is well known. However, even when the taper transitions to a near-zero wall thickness, the end of the strain relief is often able to produce a force on the flexible conduit that can kink the conduit. The problem may relate to the observation that the flexural resistance of the strain relief structure is dominated by the diameter of the strain relief (e.g. the flexibility is roughly proportional to the diameter to the 4th power). Since the diameter of the strain relief needs to be bigger than the tube in order to slide over the outside of tube, it tends to increase stiffness abruptly at this region. When flexural stiffness changes abruptly, it may produce a region that is prone to kinking.
One embodiment of the invention, depicted in FIGS. 22A and 22B, provides a strain relief structure 156 that reduces such kink points with a �flower� configuration at the end 158 of the strain relief 156 (e.g. split the end of the strain relief into flexural sections 160, thus reducing or eliminating the problem caused by the diameter disparity) to produce a very gradual change in flexibility. In some embodiments, these flexural sections 160 may have a tapered thickness and/or width to gradually increase the flexural stiffness along their length. In addition, the number of flexural sections 160 may be varied in order to tailor the strain relief's flexibility to that of the tube. The separations 162 between the flexural sections 160 are preferably rounded, or even looped with larger base opening. A rounded or looped configuration is more resistant to tearing from movement of the flexural sections 160 than straight separations between the flexural sections 160. The slits are preferably about 0 to about 0.100 inch wide, and more preferably about 0.040 to about 0.080 inch wide. The length is preferably about 0.100 to about 0.500 inch long, and more preferably about 0.200 to about 0.300 inch long. The number of slits is preferably about 3 to about 8, and most preferably about 4. The preferable material is flexible and biocompatible, such as silicone or polyurethane, but other materials may be used. Other biocompatible materials that may be used include polyethylene, homopolymers and copolymers of vinyl acetate such as ethylene vinyl acetate copolymer, polyvinylchlorides, homopolymers and copolymers of acrylates such as polymethylmethacrylate, polyethylmethacrylate, polymethacrylate, ethylene glycol dimethacrylate, ethylene dimethacrylate and hydroxymethyl methacrylate, polyurethanes, polyvinylpyrrolidone, 2-pyrrolidone, polyacrylonitrile butadiene, polycarbonates, polyamides, fluoropolymers such as homopolymers and copolymers of polytetrafluoroethylene and polyvinyl fluoride, polystyrenes, homopolymers and copolymers of styrene acrylonitrile, cellulose acetate, homopolymers and copolymers of acrylonitrile butadiene styrene, polymethylpentene, polysulfones, polyesters, polyimides, polyisobutylene, polymethylstyrene, biocompatible elastomers such as medical grade silicone rubbers, polyvinyl chloride elastomers, polyolefin homopolymeric and copolymeric elastomers, styrene-butadiene copolymers, urethane-based elastomers, and natural rubber or other synthetic rubbers, and other similar compounds known to those of ordinary skilled in the art. Polymer Handbook, Fourth Edition, Ed. By J. Brandup, E. H. Immergut, E. A. Grulke and D. Bloch, Wiley-Interscience, NY, Feb. 22, 1999.
4. Improved Crimping
As previously disclosed, the graft and/or catheter sections of the VAS may be attached to a conduit connector using a variety of structures, including crimp rings. One of ordinary skill in the art will understand that many crimping methods may be suitably used for the invention. In one particular embodiment, the crimp ring, following the crimping procedure, comprises one or more protrusions on its outer surface. These projections provided friction sites for resisting displacement of a connector sleeve that may be overlying the crimp ring(s). Referring to FIGS. 34A and 34B, one embodiment of the invention for such a crimp ring may comprise a crimp tool 292 with crimping surfaces 294 with one or more indentations 292. The indentations 296 allow one or more portions of the crimp ring to project outwardly during the crimp process.
5. Implantation of the Vascular Access System
In some embodiments of the invention, the low profile of the VAS, combined with the ease of inserting the catheter section of the VAS into the vasculature, allows the use of a minimally invasive procedure to implant the device in the body. Depending upon the diameter of the catheter section of the VAS, the catheter section may be inserted into the vein using an open surgery technique, or preferably a venous cutdown, or most preferably by Seldinger technique. These techniques are well known procedures to those of ordinary skill in the art.
Once the insertion site of the catheter section of the VAS is established, a subcutaneous pathway from the catheter section insertion site to the desired graft section attachment site may be created using any of a variety of specialized tunneling instruments or other blunt dissection tools. The VAS system is then passed through the subcutaneous pathway and the graft section is attached to the desired site. A single, uninterrupted subcutaneous pathway may be created between the insertion site and attachment site of the VAS, particularly where the VAS device comprises a unibody design. Depending upon the sites selected, the particular anatomy of a patient, the tortuosity of the desired subcutaneous pathway, and/or the modularity of the VAS, it may be desirable to create one or more intermediate surface access sites along the subcutaneous pathway to make it easier to perform the subcutaneous tunneling and/or to pass one or more sections of the VAS along the pathway. The use of intermediate surface access sites is particularly desirable, but not necessary, when implanting a multi-section VAS. The individual sections of the VAS may be implanted separately along the sections of the subcutaneous pathway, and then attached via conduit connectors or other structures at the intermediate surface access points and then buried subcutaneously.
Referring to FIGS. 23A to 23F, in one embodiment of the invention, the patient is prepped and draped in the usual sterile fashion. Either local or general anesthesia is achieved. In FIG. 23A, the brachial artery is palpated on the patient and terminal access site 164 is marked. The internal jugular (IJ) vein is located and an initial access site 166 to the IJ vein is selected using anatomical landmarks and/or radiographic visualization such as ultrasound. A guidewire is passed into the IJ vein and then a dilator is passed over the guidewire to facilitate insertion of an introducer into the IJ vein. A small scalpel incision may be needed at the guidewire insertion site if the skin and/or subcutaneous tissue create excessive resistance to the insertion of the dilator. The dilator is removed and an introducer 168 is inserted over the guidewire and into the IJ vein. The introducer 168 may be a standard or custom type of introducer. The catheter section 106 of the VAS is then inserted into the introducer, through the IJ vein and into the superior vena cava or right atrium. The position of the distal tip of the catheter section 106 is confirmed radiographically and the patient is checked for accidental collapse of the lung due to improper insertion. The introducer 168 is then removed, either by pulling the introducer over the proximal end of the catheter section, if possible, or by peeling away the introducer if a peel-away introducer was provided.
In FIG. 23B, a surgical rod 170 is then inserted into the subcutaneous space through the initial access site. The rod 170 is used to subcutaneously tunnel toward the anterior shoulder. In other embodiments, the subcutaneous tunneling and implantation of the VAS section may occur generally simultaneously. Once the anterior shoulder is reached, a scalpel is used to create an intermediate access site 172 to the rod 170. In FIG. 23C, the rod 170 is removed from the initial access site 166 and then the proximal end 174 of the catheter section 106 is passed through the subcutaneous pathway to exit from the intermediate access site 172. The same surgical rod 170 or a different rod is then inserted into the intermediate access site 172 and used to subcutaneously tunnel distally down the arm until the marked brachial artery site is reached. A terminal access site 164 to the rod is created and further exposed to access the brachial artery. The anastomosis end 171 of the graft section 102 of the VAS is attached to the brachial artery, as illustrated in FIG. 23D. Alternatively, the anastomosis may be performed after the graft section 102 is subcutaneously positioned. Referring next to FIG. 23E, the connector end 178 of the graft section 102, with pre-attached conduit connector 180, is passed from the terminal access site 164 to the intermediate access site 172. A connector sleeve with integrated strain relief structure may be passed over the proximal end 170 of the catheter section 172. The initial and terminal access sites 166, 164 are checked for any redundant conduit and pulled taut from the intermediate access site 172 if needed. The proximal end 174 of the catheter section 106 is trimmed to the desired length. About 0.5 cm to about 1 cm segment of nylon winding at the trimmed end of the catheter section is separated and cut away. The proximal end 174 of the catheter section 106 is fitted to the pre-attached conduit connector 180 of the graft section 102. The catheter section 106 is secured to the conduit connector 180 with a crimp ring and the connector sleeve is repositioned over the conduit connector. The exposed portions of the conduit connector 180, attached to the distal end 178 of the graft section 102 and the proximal end 174 of the catheter section 106, are either pulled from the graft end or pushed into the subcutaneous space through the intermediate access point 172, as illustrated in FIG. 23F. Flow through the VAS 100 is reconfirmed either by palpation or preferably by ultrasound and/or angiography. The three access sites 164, 166, 172 are sutured closed. The implanted VAS 100 is then accessed with hemodialysis needles to perform hemodialysis.
In a preferred embodiment of the invention, depicted in FIGS. 37A to 37E, the patient is placed under general anesthesia and the graft routing is marked on patient arm. The surgical site prepped, sterilized and draped. An incision 166 is made in the neck to access the lower portion of internal jugular vein. A small wire is inserted through the access site 166. The small wire is exchanged with a mid-sized introducer set (about 5F to about 14F) and the wire is removed. The vein may be angiographically assessed, and if a stenosis is identified that may preclude advancement of catheter, angioplasty may be used to enlarge the lumen of the vein. A larger wire is inserted through mid-sized introducer. The mid-sized introducer is exchanged with 20F introducer. The patient is preferably placed in Trendelenberg position prior to the removal of the dilator to reduce the propensity for air introduction upon catheter insertion. The dilator and clamp introducer is removed and the introducer is closed off with a finger. The catheter 106 is filled with heparinzed saline, clamped and inserted through the introducer. The ventilator may be optionally turned off while catheter is inserted to reduce the propensity for introduction of air. The introducer is peeled away, leaving the catheter 106 in the IJ, as shown in FIG. 37A. A �Christmas Tree� valve or atraumatic clamp (preferably a Fogarty's clamp) may be used to stop back bleed through catheter. The patient may be brought out of Trendelenberg position. The position of the catheter tip is checked under fluoroscopy for a position in the proximal to mid-right atrium (RA), and is adjusted if needed. To tunnel the catheter subcutaneously, a delta-pectoral incision 172 is made, as shown in FIG. 37B. The catheter 106 is then tunneled to the delta-pectoral incision 172 by routing above the sternocleidomastoid muscle in a sweeping fashion. Depending upon the characteristics of the catheter 106, in some instances care should be taken to not create a bend in the catheter 106 with a diameter less than about 2.5 cm to avoid kinking. The nylon filament on the catheter 106 is wound down and the catheter 106 is cut to leave approximately an inch outside of delta-pectoral incision 172. An appropriate amount of nylon winding is removed in comparison to the length of the barb on the connector 2. A connector sleeve 156 (flower end first) and crimp ring are placed over the catheter, typically in that order, depending upon the particular securing mechanism used. As depicted in FIG. 37C, the connector 2, pre-attached to the graft 102, is then attached to the catheter 106, and the catheter 106 is secured to the connector 2 using the crimp ring. The connection is tested to ensure integrity. The connector sleeve is 156 placed over most if not all the exposed metal surfaces. A brachial incision 164 is made to expose the brachial artery. An auxiliary incision site 165 is made lateral to the brachial incision site 164. The graft 102 is tunneled from the delta-pectoral site 172 or connector incision site in a lateral-inferior direction until reaching the lateral aspect of the arm. It is preferable but not required to stay superficial and also lateral to the bicep muscle. Tunneling is continued inferiorly until the auxiliary incision site 165 is reached. A tunnel from the auxiliary site 165 to the brachial site 164 is then performed to create a short upper arm loop in a �J� configuration 167 just proximal to the elbow. The graft is then tunneled cephalad along the medial aspect of the upper arm to the brachial incision site 164. Preferably, the graft 102 should be parallel to the brachial artery to allow construction of a spatulated anastomosis. The orientation line or marks are checked for an orientation in the same direction at both ends 171, 178 of the graft 102 and to verify that the catheter 106 has not moved from the proximal RA. The graft 102 is checked for a sufficient amount of slack. A parallel end-to-side anastomosis is then constructed by cutting the graft at an oblique angle and making an arteriotomy along the long axis of the brachial artery. This may be advantageous as it may cause less turbulence at the anastomotic site and may be less prone to stressing the anastomosis. The anastomosis between the artery and graft is then performed as known to those of ordinary skill in the art, as shown in FIG. 37E. A Doppler scan of the lower right arm and hand may be performed prior to closing to check whether steal syndrome occurs with the shunt. The anastomosis is checked angiographically via back-filling along the length of the VAS. Tip placement in the RA and VAS integrity with movement of the subject's arm may also be checked. Patency and absence of significant bends or kinks is also checked. The incisions are closed and dressed.
Although the embodiment described above utilizes the internal jugular vein and the brachial artery as the insertion and attachment sites, respectively, of the graft system, one with skill in the art will understand that other insertion and attachment sites may be used, and were described previously above. For example, other arteries that may be used with the invention include but are not limited to the ulnar artery, radial artery, femoral artery, tibial artery, aorta, axillary artery and subclavian artery. Other venous attachments sites may be located at the cephalic vein, basilic vein, median cubital vein, axillary vein, subclavian vein, external jugular vein, femoral vein, saphenous vein, inferior vena cava, and the superior vena cava. It is also contemplated the implantation of the device may be varied to configure the graft system in a generally linear configuration or a loop configuration, and that the insertion and attachment sites of the invention need not be in close proximity on the body. For example, attachment and insertion of the device may be performed at an axillary artery and femoral vein, respectively, or from a femoral artery to an axillary vein, respectively.
6. Catheter Inserts for Implanting the Vascular Access System
In some embodiments of the invention, specific delivery devices for inserting the VAS to a blood system are contemplated. In one specific embodiment, an insert for the catheter allows the catheter to become its own dilator. The insert is removed after implantation of the VAS. Referring to FIGS. 24A to 24I, the catheter section of the VAS is provided with a distal end 182 having a beveled edge. As illustrated in FIG. 24B, a catheter insert device 184 is provided, comprising an insert shaft 186 with a guidewire lumen 188, an expansion balloon lumen (not shown), an expansion balloon port 190, a guidewire 192, a distal tapered tip 194, an expansion balloon 196, an internal seal 198, a proximal seal 200, and a filling syringe 202. In FIG. 24C, the catheter insert device 184 is inserted into the catheter 106 and the expansion balloon 196 is inflated to preferably seal off the catheter lumen 204 at the beveled tip 182. In FIG. 24D, the catheter 106 and catheter insert 184 are advanced to the wall of a vein 206 by any of the access methods described above. Referring to FIG. 24E, the catheter lumen 204 containing the catheter insert device 184 is filled with saline or other biocompatible fluid, and the guidewire 192 is inserted into the vein. In FIG. 24F, the catheter section 106 and catheter insert 184 are then passed into the vein 206 over the guidewire 192. In FIG. 24G, the expansion balloon 196 is deflated. In FIGS. 24H and 24I, the catheter section 106 is externally compressed with a clamp 210 as the catheter insert 184 is withdrawn from the catheter section 106, to prevent blood leakage from the proximal end of the catheter section 106. The external clamp 210 is released prior to connection of the catheter section 106 to the conduit connector or graft section of the VAS. One of skill in the art will understand that many alternative catheter inserts structures are possible, including a mechanical expansion structure as depicted in FIGS. 25A and 25B, comprising a slotted tapered cylinder 212 and a plunger rod 214 that radially expands the slotted cylinder 212 by providing a radial expansion force as the plunger rod 214 is depressed against the inner surface of the slotted tapered cylinder 212.
C. Instant Access
In some embodiments of the invention, the VAS is configured to provide immediate hemodialysis access upon implantation, while reducing or eliminating the risk of hemorrhage associated with accessing the graft section of the VAS prior to its maturation or without inserting an additional catheter to provide temporary dialysis access. The instant access sites may be provided as subcutaneous needle access sites that use self-sealing materials or other structures to stop the bleeding once the hemodialysis needles are removed. The instant access sites may also comprise temporary catheters attached to VAS that exit the skin to provide external access to the VAS with a further benefit of eliminating the discomfort associated with piercing the skin to achieve hemodialysis access. These and other embodiments of the invention are discussed in further detail below. These embodiments may be well suited for integration into medical devices other than VAS, including but not limited to any of a variety of catheters, needle access ports or intravenous fluid tubing.
1. Instant Access Materials
In one embodiment of the invention, the graft or catheter material may have self-sealing properties. Self-sealing refers generally to at least at portion of the VAS wall having the ability to reseal following puncture with a sharp instrument, such as a needle. A material with self-sealing properties may be used immediately upon implantation, in contrast to traditional graft materials. No biological maturation process to improve the leakage properties of the material is required. A self-sealing material may also reduce the time required to stop bleeding from the access site following removal of the hemodialysis needles. Futhermore, the material may also be used to provide instant access sites at other sections of the VAS, or in other medical products which may benefit from self-sealing properties. The instant access material may be located anywhere along the VAS. In one embodiment of the invention, a low durometer material may be used as an instant access site. In one embodiment of the invention, low durometer materials comprise materials having a hardness of about 10 to about 30 on the Shore A scale, and preferably about 10 to about 20 on the Shore A scale. Other structures with self-sealing properties are described below.
a. Residual Compressive Stress
In one embodiment, the self-sealing conduit material is constructed by spraying a polymer, including silicone, onto a pre-existing tube of conduit material while undergoing various directional strains. The self-sealing material provides mechanical sealing properties in addition to or in lieu of platelet coagulation to seal itself. In one embodiment, the VAS comprises a self-sealing material having two or more alternating layers of residual stress coating.
In one particular embodiment, illustrated in FIG. 20, the conduit material comprises four layers, wherein the inner layer 138 is formed by axially stretching the conduit material 140, spray coating the conduit material and allowing the coating to cure, then releasing the conduit material from tension. The second layer 142 (from inner layer) is formed by twisting the conduit material 142 about its axis, spray coating and curing it, then releasing it from torque. The third layer 144 is formed by taking the conduit material from the previous step and twisting it about its axis in the opposite direction of previous step, spray coating and curing it, then releasing it from torque. The fourth layer 146 is created by taking the product from previous step, expanding it with internal pressure, spray coating and curing it, then relieving the material of pressure. Note that this may also create an axial strain since the tube elongates with pressure. A fifth optional layer 148 of an additional strain coating or a neutral coating may also be provided. The additional layer 148 may aid in achieving consistent outer diameter.
Although one example is provided above for creating a self-sealing graft or catheter material, one of ordinary skill in the art will understand that many variations of the above process may be used to create a self-sealing conduit material. One variation is to produce residual stress in the graft material by inflating and stretching the material to a thin wall and applying polymer to the wall either by dipping or spraying. The amount of circumferential and/or axial stress in the final tube may be controlled separately by adjusting the amount of inflation or axial stretch. Also, the above steps may be performed in a different order, and/or or one or more steps may be repeated or eliminated. Other variations include spraying a mandrel without using a pre-existing tube or turning the conduit material inside out (for compressive hoop stress) for one or more steps.
b. Open, Porous Structure
In another embodiment of the invention, a self-sealing portion of the VAS comprises a porous structure (e.g. material similar to Perma-Seal by Possis Medical or Vectra by Thoratec) in the wall of the VAS catheter or graft. Resistance to blood leakage in this device results from a porous wall design that provides increased surface area to promote blood clotting. In addition, the porous design can recover more readily after a needle has been left in the wall for several hours. The outer surface of the catheter is preferably porous to facilitate in-growth of tissue in order to further facilitate sealing and, more importantly, to minimize the likelihood of infection.
c. Intrawall Gel
In another embodiment of the invention, the self-sealing material comprises one or more soft inner gel layers within a wall region of the VAS. The wall region and gel layers are pierceable by a needle. As the needle is removed, the gel seals the needle tract because the gel is flexible and semi-gelatinous. A whole range of materials could be used; one specific embodiment is described in U.S. Pat. No. 5,904,967 to Ezaki; another material classification is organosiloxane polymers having the composition of:
65%�Dimethyl Siloxane 17%�Silica 9%�Thixotrol ST 4%�Polydimethylsiloxane 1%�Decamethyl cyclopentasiloxane 1%�Glycerine 1%�Titanium Dioxide 2. Improved Access Port
Referring to FIG. 21, some embodiments of the invention comprise an access port 150 with a layer of self-sealing material 152 as described above, or other self-sealing material known in the arts, such as urethane. The access port 150 provides needle access 154 to flowing blood (in order to perform hemodialysis) without the need to wait for the graft section 102 of the VAS 100 to mature or heal-in after surgery. The port 150 is constructed such that it may be accessed with needles 154 numerous times (preferably at least about approximately 12-15 times�enough for 1-month of hemodialysis). When the needle 154 is removed from the access port 150, the material 152 seals itself to prevent bleeding and hematoma formation. The access port 150 is subcutaneous and accessible via hemodialysis needles 154 through a layer of self-sealing material 152. The access port 150 may be configured to provide increased radio-opacity under either x-ray or ultrasound visualization. Other configurations for an access port are disclosed in U.S. Pat. No. 6,102,884 to Squitieri and U.S. Pat. No. 5,647,855 to Trooskin.
a. Connector Port at with Compressive Material to Seal Needle Tracts
In one embodiment, the access port comprises a layer of a compressed material as described previously, or some other type of self-sealing structure, incorporated into the connector. The compressed material causes the needle tract to close when the needle is removed. The preferred embodiment uses an elastomer, such as silicone or urethane, which is physically compressed when it is placed into the port body.
b. Needle-Activated Check Valve
In another embodiment, a check valve is incorporated into the conduit connector and is activated by inserting a needle into the connector, as shown in FIG. 36. A biased flap of material 304, such as silicone or urethane, may be used to provide normally closed opening to the blood passageway that are opened upon insertion of a needle 304 or other access device. Upon removal of the needle 306, the biased flap 304 resumes its bias so that the flap can cover or seal the hole. The connector will preferably incorporate a means to guide the needle or access device into the correct connector location. This may comprise a funnel shape and/or features that may be palpated through the skin to assist the dialysis technician in locating the connector to access it.
3. Temporary Access of the Vascular Access System
a. Temporary (Pull Out or Tear-Away) Catheter
�Temporary� refers to a catheter being used short-term (about 90 days or less, but typically about a month or less) and configured to facilitate abandonment or removal after that time. Such a device could be used in the same manner as current hemodialysis catheters except it is expected to be abandoned or removed after limited use. A temporary catheter may be connected or formed with the permanent portion of the VAS so that both can be implanted in a single procedure, but later separated or severed when no longer needed. In some embodiments, as shown in FIG. 26, the temporary catheter 216 protrudes from the skin to eliminate the need to pierce the skin during use. Thus, one advantage of a temporary catheter 216 is that it would allow dialysis to be performed immediately after surgical implantation of the VAS 100 without the severe pain associated with needle sticks immediately following surgery (as is experienced with current instant stick grafts). Another possible advantage of abandoning or removing the catheter after a limited time period is that it will decrease the likelihood of infection, especially risks associated with long-term use of hemodialysis catheters and/or with vascular access extending from out of the skin. More than one temporary catheter may be provided.
In one embodiment, the temporary catheter 216 comprises a conduit with at least one lumen, but preferably at least two lumens, which are attached to the connector 218 of the VAS 100. In other embodiments, the temporary catheter may be attached at other locations of the VAS 100. With a single lumen, infusions or blood draws may be performed from the temporary catheter device, but dialysis is more difficult to perform due to recirculation. With two or more lumens, dialysis may be performed through the temporary catheter while the graft section 102 of the VAS 100 is healing-in (typically less than about one month). Once the graft section 102 is healed-in and the patient is able to dialyze through their VAS 100, the temporary catheter 216 is disabled by removing at least a portion of the temporary catheter device 216. It is desirable to disable the temporary catheter 216 because catheters which exit the skin have a higher long-term infection rate when compared to subcutaneous grafts. The temporary catheter may optionally have a Dacron cuff near the exit site in order to reduce the rate of infection.
i. Seal Using Compressive Material at Junction
Referring to FIGS. 27A and 27B, in one embodiment of the invention, a compressive material 220 is incorporated into the conduit connector 218 and the temporary catheter 216 is attached to the connector 218 at the point of manufacture. The temporary catheter is used for about 90 days or less, but preferably less than about 1 month, and after that time, is removed in a manner similar to removing current hemodialysis catheters�it is pulled out from the site where the catheter exits through the skin. When the catheter 216 is pulled from the connector site, the compressed material 220 in the connector 218 seals the hole where the catheter 216 was removed, as shown in FIG. 27B.
ii. Seal Using Flap at Junction
Alternatively, instead of employing a compressive material to seal off the hole in the connector when the temporary catheter is removed, a biased flap of material, similar to the needle access check valve as depicted in FIG. 36, may be adapted to provide a opening to the blood passageway when engaged to a temporary catheter or other access device. Upon removal of the temporary catheter, the biased flap resumes its bias so that the flap can cover or seal the hole.
iii. Mechanical Valve at Junction
Another alternative embodiment comprises a mechanical valve instead of a flap to seal the hole in the connector when the temporary catheter is removed. One particular example is constructed using a self-closing valve set in the conduit connector or other section of the VAS. The temporary catheter fits into and may inhibit the self-sealing connection feature until removal.
Referring to FIGS. 28A and 28B, the central hub of a connector 222 may be used to house a set of mechanical valves 224, 226. One valve is the outlet 224 while the other is the inlet 226. This embodiment involves creating a pressure differential to move pistons 228, 230 along internal pathways 229, 231 between an open position and closed position, as shown in FIGS. 28A and 28B, respectively. These pistons 228, 230 may be connected to springs 232, 234 for equilibrium positioning. In the resting or closed position depicted in FIG. 28B, the piston heads 228, 230 would be flush with the inside surface 236 of said connector 222 and the piston conduits 233, 235 are out of alignment with inlet and outlet conduits 237, 239. As pressure and/or vacuum is applied from the connected tubing 241, 243, the pistons 228, 230 move from resting position to the open position to align the piston conduits 233, 235 with the inlet and outlet conduits 237, 239 so that may flow commence. When the pressure and/or vacuum is shut off, the pistons 228, 230 return to resting position, inhibiting any flow. In some further embodiments, one or both of the pistons may be configured to protrude into the connector's lumen 245 in order to reduce or eliminate the flow through the middle portion 247 of the connector 222. This may be desirable because it will help prevent or eliminate recirculation of the blood during dialysis (i.e. prevents blood from flowing directly from the outlet port from the temporary catheter and then into the inlet port of the temporary catheter).
iv. Seal with Insert Plug with Positive Locking Stop
In another alternative embodiment, the temporary catheter may be completely separated from the connector. A plug is inserted through the temporary catheter and locks into place in order to seal the hole(s) in the connector.
b. Abandoned Catheter Section
i. Seal through Lumen Using Plug/Mandrel with Positive Locking Stop
Referring to FIGS. 29A to 29C, in one embodiment, a plug 238 is inserted through the temporary catheter 216 and locked into place in order to seal the hole in the connector 222. The plug 238 may be configured such that it is generally flush with the lumen 236 of the connector 222, or where the plug minimizes sharp edges, bumps, holes or other surface irregularities that would cause turbulence as this could lead to thrombus buildup and eventual device occlusion. In this embodiment, the subcutaneous portion of the temporary catheter 216 remains in place and therefore a portion of the plug 238 may stay in the catheter 216. In some embodiments, as shown in FIG. 29C, one or more complementary detents/protrusions 240, 242 may be provided to further control the relative position of the plug 238 with the lumenal surface 236 of the connector 222.
ii. Inject Sealing Compound into Lumen
In one embodiment of the invention, a material that has the ability to solidify may be used to plug the lumens. There are several materials that may be used, such as cements, epoxies, and polymers. A preferred material is Onyx� from Micro Therapeutics, Inc. Onyx� is a liquid embolization material that may be injected through the lumens under fluoroscopic or other type of visualization. When the material comes in contact with the flowing blood, it will form a smooth surface and become solid through a precipitation reaction (e.g. DMSO is exchanged with the water in blood). More specifically, Onyx� is a liquid mixture of ethylene vinyl alcohol co-polymer (EVOH) dissolved in dimethyl sulfoxide (DMSO). Micronized tantalum powder is suspended in the liquid polymer/DMSO mixture to provide fluoroscopic visualization. The Onyx material is delivered in a liquid phase to fill the catheter lumens under fluoroscopic control. Upon contact with blood (or body fluids) the solvent (DMSO) rapidly diffuses away, causing in-situ precipitation of a soft radiopaque polymeric material. After the lumen is filled and the filling material has solidified, the temporary catheter may be cut so it lies subcutaneously. (Clinical Review of MTI, Onyx� Liquid Embolization System, available at http://www.fda.gov/ohrms/dockets/ac/03/briefing/3975b1-02-clinical-review.pdf, accessed Aug. 29, 2005).
iii. Plug Lumen at Proximal End Only
In another embodiment, the proximal end of the temporary catheter 216 is sealed using a plug, clamp, winding, suture or other method and the temporary catheter 216 is cut subcutaneously. The temporary catheter 216 may be sealed then cut, or cut then sealed. The disadvantage of this method is that there is a chance of producing turbulence where the temporary catheter ends inside the connector because there would be an abrupt transition and a blind end where blood stasis will occur.
In particular one embodiment, depicted in FIG. 30A, the temporary catheter 216 and connector 2 form a complementary lock/latch mechanism, whereby the end 244 of the temporary catheter 216 comprises a hard material, either metal or plastic, and a recess 246 containing a biased-split ring 248, and is capable of interfacing with a coupling lumen 252 in the wall 254 of the conduit connector. As shown in FIG. 30B, the coupling lumen 252 is configured with a complementary groove 250 whereby when the temporary catheter 216 is fully inserted into the coupling lumen 252, the biased-split ring 248 can snap into the groove 250 to lock the temporary catheter 216 into the coupling lumen 252 on the conduit connector. In an alternative embodiment, the recess and biased-spit ring may be positioned in the coupling lumen while the end 244 of the temporary catheter 216 has a complementary groove. One of skill in the art will understand that any of a variety of other securing structures may also be used, including but not limited to biased projecting prongs and threaded rotation interfaces.
Once the temporary catheter 216 is no longer needed, the temporary catheter 216 may be plugged or filled, and severed about its proximal end 244. By severing the temporary catheter 216, the amount of foreign body remaining in the patient is reduced, which in turn may reduce the risk of infection, immune system response, and/or cosmetic effect.
Referring back to FIG. 30B, a plug 256 with an insertion stop 258 and one or more ramped edges 260 along its surface is inserted into the lumen 262 of the temporary catheter 216. The ramped edges 260 of the plug 256 provide resistance to backout for the plug 256 while the insertion stop 258 allows the plug 256 to seat in the end 244 of the temporary catheter 216 without protruding excessively past the wall 254 of the connector. The plug 256 is inserted into the temporary catheter 216 using a catheter cutter 264 with a retractable blade 266. The catheter cutter 264 is used to push the plug 256 into the catheter lumen 262. Once the plug 256 is in place, the retractable blade 266 is extended from the catheter cutter 264 and the catheter cutter 264 is rotated or otherwise manipulated to sever at least a portion of the temporary catheter 216 from its end 244. The retractable blade 266 is retracted and the separated portion of the temporary catheter 216 is removed from the patient along with the catheter cutter 264. The end 244 of the temporary catheter 216 and plug 256 remain in the coupling lumen 252 of the wall 254 of the connector and seal it from blood leakage.
C. Implantation of Temporary Access
In one embodiment for implanting the VAS with a temporary access structure, the pathway for the catheter section of the VAS is tunneled first, the pathway for the pre-connected graft section of the VAS is tunneled next, followed preferably by the tunneling of a pathway from the intermediate access site to a temporary catheter exit site. It is preferable that the temporary catheter be located at a tunneled exit site rather than project directly out of the intermediate access site where the catheter section is attached to the graft section, in order to reduce the risk of infection of the main VAS assembly. By increasing the distance between the connector to the skin site where the temporary catheter exits the body, infection of the connector is reduced. After the temporary catheter is tunneled from the chest to the connector, the catheter is locked or latched into the connector, as described in embodiments disclosed above. The temporary catheter may also be tunneled from the connector to the exit site.
Typically, when using an AV shunt for hemodialysis access, the blood is directly taken from an artery and shunted to a vein. The flow through the shunt needs to be sufficiently high so that there is more blood flow in the shunt than is required by the dialysis circuit, otherwise recirculation of already-dialyzed blood will occur in the system, reducing dialysis efficiency. Thus, for dialysis, high flow in the shunt is desirable. On the other hand, high flow can be detrimental to the patient. The shunted blood is not available for perfusing the body tissue. The body will try to compensate for the reduced tissue perfusion by increasing the cardiac output. This creates in an increased workload on the heart, which can result in high-output heart failure. The shunt can also result in insufficient flow below the point where the blood exits the artery in the shunt, thereby under-perfusing the tissue below that point (steal syndrome). Ideally, flow through the shunt should be controlled to have high flow during dialysis and low flow between dialysis. One way of accomplishing this is to build a shunt that can be manipulated to provide high flow rates during dialysis and then low flow between dialysis.
Referring to FIGS. 31A to 31D, in one embodiment, the VAS contains at least one flow control section 268 comprising a dual-compartment deformable tubing. One compartment is the blood path 270 for the VAS, while the other acts as a distensible reservoir 272 for fluid. The reservoir 272 shares a compliant common wall 274 with the blood path 270 of the VAS. When the reservoir 272 is distended, the compliant common wall 274 is able to compress the blood path 270 to a reduced cross-sectional area, thereby reducing blood flow through the blood path 270. Some degree of blood flow through the blood path 270 is generally preferred at all times to maintain patency and to reduce the risk of thrombosis. To use the flow control section 268, fluid is injected into the reservoir 272 between dialysis procedures, which restricts the blood flow between sessions. At the time of dialysis, fluid is withdrawn from the reservoir 272, which allows the blood flow through the blood path 270 to increase.
In an alternate embodiment of the invention, depicted in FIGS. 32A and 32B, multi-lumen tubing 276 is provided wherein one lumen 278 is shut off between dialysis but two or more lumens 278, 280 are available during dialysis. This tubing 276 may be formed by manufacturing the tubing 276 with a lumen 278 biased to the reduced configuration, but can be expanded to an enlarged position by the increased flow and/or pressure provided during hemodialysis. In another alternative embodiment, flow control may be achieved by a mechanical clamp integrated with the VAS that is actuatable through the skin and is able to at least partially compress the blood path to reduce flow through the VAS when dialysis is not being performed.
E. Flow Monitoring
In one embodiment of the invention, the VAS further comprises a flow sensor mounted in the device, typically in the catheter section. A flow sensor allows the dialysis unit to directly determine the flow rate in the VAS and verify that it is sufficient to perform routine dialysis. For example, if flow through the VAS is too low, dialysis will occur with a large amount of recirculation in the system, resulting in inadequate dialysis. Real-time detection of reduced flow during the dialysis will also provide an early indication of blockage in the graft and provide the opportunity to take preventative action to prevent the system from shutting down. There are a variety of methods known in the art by which blood flow can be measured. Ideally, the measurement should be non-invasive which would mean some sort of imbedded sensor which can be interrogated by a measuring device using electromagnetic signal from the device. This is done frequently with pacemakers and implanted electronic devices.
One embodiment of a flow sensor is depicted in FIG. 33. The flow sensor 282 may be housed in part of the conduit connector or another region of the VAS. The sensing element 284 of the flow sensor 282 may be based upon any of a variety of methods known in the art, which include but are not limited to thermal, heat dissipation as a function of flow, thermal rise for a specific heat input, pressure drop across a known distance, along a length of the device, across a metering orifice, impact pressure, wall stress from fluid shear, magnetic flow, Doppler flow, a sensor for saline injection, or any a combination thereof. Those with skill in the art will understand that many flow sensor designs may also be used.
The flow sensing element 284 is attached to the various additional electronics 286 that may also be located in the wall of the VAS, or in a separate housing attachable to the wall of the VAS. This in turn is connected to an antenna 288 imbedded in the wall of the catheter or in the separate housing. The antenna 288 can be used to transmit data from the flow sensor 282 to an external receiver 290, but also preferably to power the device from and external source. In other embodiments, a wired connection that is accessible from outside the body may be provided from the flow sensor, in lieu of or in additional to wireless transmission between the components.
The measurement of blood flow may be performed directly, or more typically, indirectly. In a preferred embodiment of the invention, the pressure differential between two (or more) locations in the catheter are measured and the flow is calculated. The flow in the catheter is approximately given by Poiseuille's Equation:
Q=ΔPπr 4/8ηl Where Q is flow rate, ΔP is the pressure differential, r is the radius of the catheter lumen, η is the viscosity, and l is the distance between the pressure measurement points. The equation shows that the flow rate is very sensitive to the radius of the catheter. However, the catheter is relatively non-thrombogenic compared to the graft and therefore one may approximate the flow rate by assuming that the catheter remains at a constant radius. In the preferred embodiment, the flow monitoring components of the VAS comprise an external component and an internal component.
In one embodiment, the external component comprises a power supply, a transmitter, a receiver, a signal processor and a flow readout. The VAS flow monitor may be powered by standard wall outlet electricity or by battery. If standard wall outlet power is used, the power supply regulates the voltage to match the requirements of the other components. The power supply may be used to power both the external device and the internal device. The transmitter comprises an antenna and a tuned circuit that transmits a radio frequency (RF) signal. The RF signal is tuned for optimal coupling to the implanted device in order to transfer power to the implanted device. A receiver is also contained in the external component. The receiver receives the flow signals from the implanted portion of the flow monitor. This antenna is tuned for optimal reception with the output signal of the implanted device. Preferably, the transmitter and receiver would use the same antenna. The signal processor takes the signal from the receiver, analyzes the signals to determine the flow rate, and converts the flow rate into an electronic format so the flow can be displayed by the flow readout. Electronic circuits are well known for converting electronic signals to a format that can be readily displayed. More details of the signal analysis are given below. In other embodiments of the invention, the flow rate information is not converted to an electronic format and instead is displayed on a calibrated analog display. Thus, the flow readout may comprise a standard digital or analog readout that provides a display of the flow value.
The internal or implanted component of the flow monitor comprises a receiver, a flow sensing unit, a signal processor and a transmitter. The receiver receives the RF signal from the external device and uses it to provide power to operate the other components in the implanted device. The preferred shape of the antenna is a coil embedded into the catheter wall. The preferred embodiment of the flow sensing unit comprises a series of individual pressure transducers embedded into the wall of the catheter. In some embodiments, the transducers are embedded into the catheter rather than the graft (ePTFE) because the catheter typically is made of a material (e.g. silicone) that is considerable less thrombogenic than the graft, thus allowing one to assume that the catheter diameter remains constant. One group of pressure transducers are separated by a known distance from another group of transducers by a known distance in order to measure the pressure drop from one portion of the catheter to another portion of the catheter. In one embodiment, each group of pressure transducers comprises one transducer, but in other embodiments, one or more group comprise at least two transducer each, spaced along the circumference, in order to allow averaging for more accurate measurements. Pressure transducer groups with multiple transducers about a circumference may compensate for possible localized pressure variations due to bends in the catheter and other local bias factors.
Although various types of pressure transducers are contemplated for the invention, one of the most common is the strain-gauge transducer. The conversion of pressure into an electrical signal is achieved by the physical deformation of strain gauges which are bonded into the diaphragm of the pressure transducer and wired into a Wheatstone bridge configuration. Pressure applied to the pressure transducer produces a deflection of the diaphragm which introduces strain to the gauges. The strain will produce an electrical resistance change proportional to the pressure. The strain gauges may be covered with a thin, flexible biocompatible material such as silicone or urethane and be positioned on the inside surface of the catheter for maximum sensitivity.
The signal processor for the implantable component takes the signals from each one of the transducers and, in the preferred embodiment, it amplifies, encodes, and multiplexes each signal for transmission by the transmitter so the external component can decode and identify the readings from each of the individual transducers. The electronics may be preferably designed to keep all of the time-dependent information (the pulse waveform) of the signals for analysis by the external system.
In another embodiment, the pressure monitoring system may be used to assess for possible clot formation in the catheter using the temporal information of the pulse waveform to help determine flow rate. For example, if the graft section begins to clot while the catheter remains patent, the absolute pressure in the catheter will drop, the pressure differential between the transducers will also drop, and the waveform shape will change to a less resistive shape (pressure waveform looks more like waveform of the central venous system). The external component of the flow monitoring system will analyze this information and determine the flow rate. On the other hand, if the catheter begins to form clot and the flow slows, the waveform shape will continuously become more resistive with decreased flow. In addition, the pressure differential will increase and the absolute pressure will decrease as the flow decreases. This will occur until the pressure differential reaches a threshold, at this point both pressures will drop with decreased flow. The transmitter is driven by the electronics and preferable uses the receiver antenna to transmit the RF signals to the external device.
While this invention has been particularly shown and described with references to embodiments thereof, it will be understood by those skilled in the art that the various changes in form and details may be made therein without departing from the scope of the invention. For all of the embodiments described above, the steps of the methods need not be performed sequentially. Furthermore, any references above to either orientation or direction are intended only for the convenience of description and are not intended to limit the scope of the invention to any particular orientation or direction.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS3363926May 14, 1965Jan 16, 1968Nat Lock CoLocking mechanism for a door lock assemblyUS3490438Jun 8, 1967Jan 20, 1970Atomic Energy CommissionPerfusion chamber and cannulae thereforUS3683926Jul 9, 1970Aug 15, 1972Dainippon Pharmaceutical CoTube for connecting blood vesselsUS3814137Jan 26, 1973Jun 4, 1974Baxter Laboratories IncInjection site for flow conduits containing biological fluidsUS3818511Nov 17, 1972Jun 25, 1974Medical Prod CorpMedical prosthesis for ducts or conduitsUS3826257Jul 14, 1972Jul 30, 1974T BuselmeierProsthetic shuntUS3882862Jan 11, 1974May 13, 1975Olga BerendArteriovenous shuntUS3998222May 15, 1975Dec 21, 1976Shihata Alfred ASubcutaneous arterio-venous shunt with valveUS4076023Aug 1, 1975Feb 28, 1978Erika, Inc.Resealable device for repeated access to conduit lumensUS4133312Oct 13, 1976Jan 9, 1979Cordis Dow Corp.Connector for attachment of blood tubing to external arteriovenous shunts and fistulasUS4184489Dec 1, 1977Jan 22, 1980Cordis Dow Corp.Infusion tube access siteUS4214586Nov 30, 1978Jul 29, 1980Ethicon, Inc.Anastomotic coupling deviceUS4318401Apr 24, 1980Mar 9, 1982President And Fellows Of Harvard CollegePercutaneous vascular access portal and catheterUS4447237May 7, 1982May 8, 1984Dow Corning CorporationValving slit construction and cooperating assembly for penetrating the sameUS4496349Oct 26, 1981Jan 29, 1985Renal Systems, Inc.Percutaneous implantUS4496350Jun 23, 1983Jan 29, 1985Renal Systems, Inc.For providing access to the circulatory systemUS4503568Nov 25, 1981Mar 12, 1985New England Deaconess HospitalProsthetic arterial connectorUS4550447Aug 3, 1983Nov 5, 1985Shiley IncorporatedVascular graft prosthesisUS4619641Nov 13, 1984Oct 28, 1986Mount Sinai School Of Medicine Of The City University Of New YorkCoaxial double lumen anteriovenous graftsUS4655771Apr 11, 1983Apr 7, 1987Shepherd Patents S.A.Prosthesis comprising an expansible or contractile tubular bodyUS4734094Jun 9, 1986Mar 29, 1988Jacob Erwin TCatheter and method for cholangiographyUS4753236Nov 9, 1987Jun 28, 1988Healey Maureen AFor temporarily rejoining and reforming a damaged blood vesselUS4771777Jan 6, 1987Sep 20, 1988Advanced Cardiovascular Systems, Inc.Perfusion type balloon dilatation catheter, apparatus and methodUS4772268Nov 3, 1986Sep 20, 1988Cook IncorporatedTwo lumen hemodialysis catheterUS4786345Jan 28, 1987Nov 22, 1988Instituform Licencees B.V.Impregnating lining with curable synthetic resinUS4790826Mar 28, 1986Dec 13, 1988Elftman Nancy WPercutaneous access portUS4822341Nov 20, 1987Apr 18, 1989Impra, Inc.Vascular access fistulaUS4848343Oct 30, 1987Jul 18, 1989Medinvent S.A.Device for transluminal implantationUS4850999May 26, 1981Jul 25, 1989Institute Fur Textil-Und Faserforschung Of StuttgartFlexible hollow organUS4856938Dec 15, 1987Aug 15, 1989Bomag-Menck GmbhMethod of and arrangement for separating tubular foundation piles under waterUS4877661Oct 19, 1987Oct 31, 1989W. L. Gore & Associates, Inc.Rapidly recoverable PTFE and process thereforeUS4898669Jun 13, 1988Feb 6, 1990Claber S.P.A.Vascular access device, in particular for purification treatments of the bloodUS4917067Aug 8, 1988Apr 17, 1990Ngk Spark Plug Co., Ltd.System for controlling air-fuel ratio of combustible mixture fed to internal combustion engineUS4917087Aug 30, 1988Apr 17, 1990Walsh Manufacturing (Mississuaga) LimitedAnastomosis devices, kits and methodUS4929236May 26, 1988May 29, 1990Shiley Infusaid, Inc.Snap-lock fitting catheter for an implantable deviceUS4955899May 26, 1989Sep 11, 1990Impra, Inc.Longitudinally compliant vascular graftUS5026513May 22, 1989Jun 25, 1991W. L. Gore & Associates, Inc.Process for making rapidly recoverable PTFEUS5041098May 19, 1989Aug 20, 1991Strato Medical CorporationVascular access system for extracorporeal treatment of bloodUS5053023Feb 25, 1991Oct 1, 1991Vas-Cath IncorporatedCatheter for prolonged accessUS5061275Dec 29, 1989Oct 29, 1991Medinvent S.A.Self-expanding prosthesisUS5064435Jun 28, 1990Nov 12, 1991Schneider (Usa) Inc.Self-expanding prosthesis having stable axial lengthUS5104402Mar 20, 1990Apr 14, 1992Trustees Of The University Of PennsylvaniaProsthetic vessels for stress at vascular graft anastomosesUS5171227 *Apr 16, 1991Dec 15, 1992The Curators Of The University Of MissouriSeparable peritoneal dialysis catheterUS5171305Oct 17, 1991Dec 15, 1992Imagyn Medical, Inc.Linear eversion catheter with reinforced inner body extensionUS5192289Dec 23, 1991Mar 9, 1993Avatar Design And Development, Inc.Anastomosis stent and stent selection systemUS5192310Sep 16, 1991Mar 9, 1993Atrium Medical CorporationSelf-sealing implantable vascular graftUS5197976Sep 16, 1991Mar 30, 1993Atrium Medical CorporationManually separable multi-lumen vascular graftUS5330500Oct 17, 1991Jul 19, 1994Song Ho YSelf-expanding endovascular stent with silicone coatingUS5399168Jul 29, 1992Mar 21, 1995C. R. Bard, Inc.Implantable plural fluid cavity portUS5454790May 9, 1994Oct 3, 1995Innerdyne, Inc.Method and apparatus for catheterization accessUS5476451Mar 17, 1995Dec 19, 1995Michigan Transtech CorporationImplantable access devicesUS5496294Jul 8, 1994Mar 5, 1996Target Therapeutics, Inc.Catheter with kink-resistant distal tipUS5509897Feb 15, 1995Apr 23, 1996The Curators Of The University Of MissouriMultiple lumen catheter for hemodialysisUS5558641Jan 13, 1995Sep 24, 1996Sims Deltec, Inc.Hybrid portal and methodUS5562617Jan 18, 1994Oct 8, 1996Finch, Jr.; Charles D.Implantable vascular deviceUS5562618Jan 21, 1994Oct 8, 1996Sims Deltec, Inc.Portal assembly and catheter connectorUS5591226Jan 23, 1995Jan 7, 1997Schneider (Usa) Inc.Percutaneous stent-graft and method for delivery thereofUS5607463Mar 30, 1993Mar 4, 1997Medtronic, Inc.Containing at least one tisue contacting surface comprising base material and thin layer of group five/b metal; prostheticsUS5637088Sep 14, 1995Jun 10, 1997Wenner; Donald E.System for preventing needle displacement in subcutaneous venous access portsUS5637102May 24, 1995Jun 10, 1997C. R. Bard, Inc.Dual-type catheter connection systemUS5647855Jul 5, 1994Jul 15, 1997Trooskin; Stanley Z.For peritoneal dialysisUS5669881Jan 10, 1995Sep 23, 1997Baxter International Inc.Vascular introducer system incorporating inflatable occlusion balloonUS5674272Jun 5, 1995Oct 7, 1997Ventritex, Inc.Crush resistant implantable leadUS5676346Aug 29, 1996Oct 14, 1997Ivac Holdings, Inc.Needleless connector valveUS5743894Jun 7, 1995Apr 28, 1998Sherwood Medical CompanySpike port with integrated two way valve accessUS5755773Jun 4, 1996May 26, 1998Medtronic, Inc.Endoluminal prosthetic bifurcation shuntUS5755775 *Sep 3, 1996May 26, 1998Schneider (Usa) Inc.Percutaneous stent-graft and method for delivery thereofUS5792104Dec 10, 1996Aug 11, 1998Medtronic, Inc.Dual-reservoir vascular access portUS5797879Aug 26, 1996Aug 25, 1998Decampli; William M.Apparatus and methods for providing selectively adjustable blood flow through a vascular graftUS5800512Jan 22, 1996Sep 1, 1998Meadox Medicals, Inc.PTFE vascular graftUS5800522Jan 24, 1997Sep 1, 1998W. L. Gore & Associates, Inc.Interior liner for tubes, pipes and blood conduitsUS5810870Jun 7, 1995Sep 22, 1998W. L. Gore & Associates, Inc.Intraluminal stent graftUS5829487Jul 3, 1997Nov 3, 1998Eat Elektronische Ateliertechnik Textil GmbhMethod for representing a fabric consisting of warp and weft threadsUS5830224Mar 15, 1996Nov 3, 1998Beth Israel Deaconess Medical CenterCatheter apparatus and methodology for generating a fistula on-demand between closely associated blood vessels at a pre-chosen anatomic site in-vivoUS5840240Nov 3, 1995Nov 24, 1998Possis Medical, Inc.Method of making a silicone composite vascular graftUS5866217Nov 4, 1991Feb 2, 1999Possis Medical, Inc.Silicone composite vascular graftUS5904967Apr 25, 1996May 18, 1999Terumo Kabushiki KaishaPolyester layer, styrene elastomer, olefin elastomer, isoprene derivative; artificial blood vesselsUS5931829May 15, 1997Aug 3, 1999Vasca, Inc.Methods and systems for establishing vascular accessUS5931865Nov 24, 1997Aug 3, 1999Gore Enterprise Holdings, Inc.Multiple-layered leak resistant tubeUS5957974Oct 8, 1997Sep 28, 1999Schneider (Usa) IncStent graft with braided polymeric sleeveUS5997562Mar 24, 1998Dec 7, 1999Percusurge, Inc.Medical wire introducer and balloon protective sheathUS6001125Mar 18, 1998Dec 14, 1999Meadox Medicals, Inc.PTFE vascular prosthesis and method of manufactureUS6019788Nov 4, 1997Feb 1, 2000Gore Enterprise Holdings, Inc.Vascular shunt graft and junction for sameUS6036724Jan 16, 1998Mar 14, 2000Meadox Medicals, Inc.PTFE vascular graft and method of manufactureUS6102884 *Apr 7, 1997Aug 15, 2000Squitieri; RafaelSquitieri hemodialysis and vascular access systemsUS6156016Nov 19, 1999Dec 5, 2000Maginot Vascular SystemsCatheter systems and associated methods utilizing removable inner catheter or cathetersUS6231085May 14, 1998May 15, 2001Irrigation Development CompanyTubing coupling and hose end combination, and related methodUS6255396Sep 9, 1999Jul 3, 2001Baxter International Inc.Cycloolefin blends and method for solvent bonding polyolefinsUS6261255Nov 6, 1998Jul 17, 2001Ronald Jay MullisTubing for arteriovenous fistula composed of polytetrafluoroethylene, silicone or fluorosilicone; clogging and occlusion resistantUS6261257May 24, 1999Jul 17, 2001Renan P. UflackerDialysis graft system with self-sealing access portsUS6319279Oct 15, 1999Nov 20, 2001Edwards Lifesciences Corp.Laminated self-sealing vascular access graftUS6338724Mar 29, 1999Jan 15, 2002Christos D. DossaArterio-venous interconnectionUS6398764Dec 27, 1999Jun 4, 2002Vasca. Inc.Subcutaneously implanted cannula and method for arterial accessUS6402767Mar 6, 2000Jun 11, 2002Kensey Nash CorporationAnastomosis connection system and method of useUS6428571Mar 14, 2000Aug 6, 2002Scimed Life Systems, Inc.Self-sealing PTFE vascular graft and manufacturing methodsUS6436132Mar 30, 2000Aug 20, 2002Advanced Cardiovascular Systems, Inc.Composite intraluminal prosthesesUS6582409Jan 24, 2000Jun 24, 2003Graftcath, Inc.Hemodialysis and vascular access systemsUS6585762Nov 1, 2000Jul 1, 2003Paul StanishArteriovenous grafts and methods of implanting the sameUS6689096Oct 5, 1998Feb 10, 2004Soprane S.A.Multipurpose catheterUS6689157Dec 21, 2001Feb 10, 2004Endologix, Inc.Dual wire placement catheterUS6692461Aug 7, 2001Feb 17, 2004Advanced Cardiovascular Systems, Inc.Catheter tipUS6699233Apr 10, 2001Mar 2, 2004Scimed Life Systems, Inc.Locking catheterUS20020151761 *Feb 15, 2002Oct 17, 2002Anthony VioleImplantable heart assist system and method of applying same* Cited by examinerNon-Patent CitationsReference1Anatole Besarab et al., "Measuring the Adequacy of Hemodialysis Access", Current Opinion in Nephrology and Hypertension, Rapid Science Publishers ISSN 1062-4821, 1996, 5:527-531.2Clinical Review of MTI, Onyx� Liquid Embolization System, available at http://www.fda.gov/ohrms/dockets/ac/03/ briefing/3975b1-02-clinical-review.pdf , accessed Aug. 29, 2005.3Co-Pending U.S. Appl. No. 10/219,998 and its prosecution history, Apr. 2009.4Coulson, A.S., M.D., et al., A Combination of the Elephant Trunk Anastomosis Technique and Vascular Clips for Dialysis Grafts, Surgical Rounds, Nov. 1999, pp. 596-608.5Coulson, Alan S., M.D., et al., Modification of Venous End of Dialysis Grafts: An Attempt to Reduce Neointimal Hyperplasia, Dialysis & Transplantation, vol. 29, No. 1, Jan. 2000, pp. 10-18.6David A. Kumpe et al., "Angioplasty/Thrombolytic Treatment of Failing and Failed Hemodialysis Access Sites: Comparison with Surgical Treatment", Progress in Cardiovascular Diseases, vol. XXXIV, No. 4 (Jan./Feb.), 1992: pp. 263-278.7International Search Report and Written Opinion for PCT Application No. PCT/US05/310124 dated Mar. 12, 2007.8International Search Report and Written Opinion for PCT Application No. PCT/US2006/044564 dated Jun. 20, 2007.9International Search Report and Written Opinion for PCT Application No. PCT/US2009/035923 dated Jun. 3, 2009.10International Search Report for PCT Application No. PCT/US98/01939 dated May 5, 1998.11Interview Summary dated Mar. 11, 2009 for Co-Pending U.S. Appl. No. 11/417,658 in 4 pages.12L.C. Koo Seen Lin et al., "Contemporary Vascular Access Surgery for Chronic Haemodialysis", The Royal College of Surgeons of Edinburgh, J.R. Coll. Surg. Edinb., 41, Jun. 1996, 164-169.13Methem J.A. Sharafuddin, MD et al., Dialysis Access Intervention, "Percutaneous Balloon-assisted Aspiration Thrombectomy of Clotted Hemodialysis Access Grafts", Journal of Vascular and Interventional Radiology, vol. 7, No. 2, Mar.-Apr. 1996, pp. 177-183.14Office Action in Japanese Patent Application No. 2007-530325 mailed Dec. 8, 2009.15PCT Notification of Transmittal of the International Search Report and the Written Opinion of the International Searching Authority.16Robert Y. Kanterman, MD et al., Intervention Radiology, "Dialysis Access Grafts: Anatomic Location of Venous Stenosis and Results of Angioplasty", Radiology Apr. 1995, vol. 195, No. 1, 195:135-139.17Search Report for EP Application No. 05006233.0 dated Jun. 8, 2005.18Seshadri Raju, M.D., PTFE Grafts for Hemodialysis Access, "Techniques for Insertion and Management of Complications", Ann. Surg. vol. 206, No. 5, Nov. 1987, pp. 666-673.19U.S. Appl. No. 10/219,998, filed Aug. 15, 2002, Squitieri, Prosecution Events: Office Actions: May 9, 2003; Apr. 27, 2004; Oct. 19, 2004; Apr. 9, 2007; Oct. 7, 2008 Amendments: Nov. 10, 2003; Aug. 30, 2004; Jan. 31, 2005; May 23, 2005; Sep. 10, 2007; Nov. 3, 2008; Jun. 16, 2009.Referenced byCiting PatentFiling datePublication dateApplicantTitleUS8366685Apr 26, 2012Feb 5, 2013Creative Vascular, LlcSystems and methods for phlebotomy through a peripheral IV catheterUS8808246Jul 20, 2010Aug 19, 2014The General Hospital CorporationPeripheral blood sampling methods and devicesWO2013036643A2Sep 6, 2012Mar 14, 2013Hemosphere, Inc.Vascular access system with connectorWO2014028787A2 *Aug 15, 2013Feb 20, 2014Novita TherapeuticsBlood pump systems and methodsWO2015023460A1Aug 4, 2014Feb 19, 2015Cryolife, Inc.Systems and methods for a fluid carrying conduit of a vascular access system* Cited by examinerClassifications U.S. Classification604/6.16, 604/8, 604/507, 604/508International ClassificationA61F2/06, A61B17/11, A61M31/00, A61M1/10, A61M1/36, A61M37/00, A61M39/10Cooperative ClassificationA61M1/3653, A61F2/064, A61M1/1008, A61B17/11, A61M39/10, A61M1/3661, A61B2017/1135, A61B2017/1132, A61B2017/1107, A61M1/3655European ClassificationA61M1/36C7, A61M1/36C7A, A61B17/11Legal EventsDateCodeEventDescriptionDec 13, 2013FPAYFee paymentYear of fee payment: 4May 17, 2012ASAssignmentOwner name: GENERAL ELECTRIC CAPITAL CORPORATION, AS AGENT, MAFree format text: SECURITY AGREEMENT;ASSIGNOR:HEMOSPHERE, INC.;REEL/FRAME:028233/0305Effective date: 20120517Jul 7, 2010ASAssignmentFree format text: CHANGE OF NAME;ASSIGNOR:HEMOSPHERE MERGER CORP.;REEL/FRAME:24640/716Effective date: 20100311Owner name: HEMOSPHERE, INC.,MINNESOTAOwner name: HEMOSPHERE, INC., MINNESOTAFree format text: CHANGE OF NAME;ASSIGNOR:HEMOSPHERE MERGER CORP.;REEL/FRAME:024640/0716Mar 12, 2010ASAssignmentOwner name: HEMOSPHERE MERGER CORP.,MINNESOTAFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HEMOSPHERE, INC.;US-ASSIGNMENT DATABASE UPDATED:20100316;REEL/FRAME:24079/130Effective date: 20100309Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HEMOSPHERE, INC.;REEL/FRAME:24079/130Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HEMOSPHERE, INC.;REEL/FRAME:024079/0130Owner name: HEMOSPHERE MERGER CORP., MINNESOTADec 9, 2005ASAssignmentOwner name: GRAFTCATH, INC., MINNESOTAFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:PORTER, CHRISTOPHER H.;ZIEBOL, ROBERT J.;HERRIG, JUDSON A.;AND OTHERS;REEL/FRAME:017338/0417;SIGNING DATES FROM 20051111 TO 20051116Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:PORTER, CHRISTOPHER H.;ZIEBOL, ROBERT J.;HERRIG, JUDSON A. 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