Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M25/00—Catheters; Hollow probes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M25/00—Catheters; Hollow probes
  • A61M25/0043—Catheters; Hollow probes characterised by structural features
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M25/00—Catheters; Hollow probes
  • A61M25/01—Introducing, guiding, advancing, emplacing or holding catheters
  • A61M25/0105—Steering means as part of the catheter or advancing means; Markers for positioning
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • A61B17/22—Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for
  • A61B2017/22082—Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for after introduction of a substance
  • A61B2017/22084—Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for after introduction of a substance stone- or thrombus-dissolving
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M25/00—Catheters; Hollow probes
  • A61M25/0067—Catheters; Hollow probes characterised by the distal end, e.g. tips
  • A61M25/0068—Static characteristics of the catheter tip, e.g. shape, atraumatic tip, curved tip or tip structure
  • A61M25/007—Side holes, e.g. their profiles or arrangements; Provisions to keep side holes unblocked

Definitions

• the present invention relates to a sub-microcatheter and to a method for treating a blockage in a vessel caused by a thrombus.
• a blockage is formed within a vessel by a thrombus or a clot.
• an objective is to remove the blockage caused by the thrombus as quickly as possible.
• the thrombus is comprised of various blood components that can be dissolved or lysed with drugs.
• these lytic drugs are given by systemic intravenous (IV) administration. Consequently, a drug is infused throughout the entire circulatory system.
• a more aggressive treatment is to deliver the lytic drugs directly to the thrombus utilizing a catheter.
• the catheter is positioned adjacent to the thrombus and the drug is infused directly onto the thrombus.
• the benefit is that the drug, in a much higher concentration, reaches the thrombus for improved effectiveness.
• Microcatheters that are intended for insertion into the vasculature of the brain rely upon the flexibility of polymeric material from which the microcatheters are fabricated for the characteristics of trackability and pushability.
• Trackability refers to a characteristic of a microcatheter to "track over" a guidewire to an intended treatment location. Microcatheters must exhibit superior trackability to traverse the tortuous anatomy in the brain.
• Pushability refers to a characteristic of a microcatheter to transmit an axial pushing force from a proximal end of the catheter, which is the operator end, to a distal end of the microcatheter, the end of the catheter in the patient. Physicians expect that they can push the microcatheter effortlessly within the anatomy of a living being.
• Microcatheters are typically designed to enhance these characteristics with a particular polymer selection for the catheter body or a catheter shaft. Polymers may be blended or coextruded to provide a proper mix of flexibility and rigidity.
• a microcatheter shaft may vary in flexibility over its length, being more flexible and less rigid at a distal end of the microcatheter and less flexible .and more rigid at the proximal end of the micro catheter. This result may also be accomplished by varying the microcatheter shaft diameter and wall thickness.
• the Engelson patent, U.S. No. 4,739,768, issuing April 26, 1988, and Re- examination Certificate No. B14739768, issuing June 16, 1993, describes a catheter used in conjunction with a guidewire for treating a target tissue.
• the catheter includes an elongate tubular member with a proximal end and a distal end, the tubular member defining an inner lumen.
• the tubular member has a stiff proximal segment making up about 70% to 95% of the total length of the tubular member as well as a flexible distal segment that makes up the remaining 5% to 30% of the length of the tubular member.
• the proximal segment defines inner and outer coaxial tubes.
• a Samson et al. patent U.S. No. 5,462,523, issuing October 31, 1995, describes a catheter for delivering drugs to regions of a human body accessible through systems of passage ways, such as blood vessels.
• the catheter includes a guidewire and a tubular elongate body.
• the elongate body includes a distal segment that is flexible thereby rendering the catheter trackable along the guidewire.
• the main body further includes a profusion tip with an opening permitting a perfusion of drugs at a particular site.
• the tip is made up of an inner stiffener which is somewhat porous and an outer profuser layer which controls fluid flow to a relatively low rate.
• the sub-microcatheter of the present invention includes a unitary, flexible main body defining a lumen having a distal end and a proximal end.
• a mandril is positionable within the sub-microcatheter and imparts to the main body flexibility and rigidity that is effective for optimizing trackability and steerability of the sub-microcatheter within vessels of a living being.
• the present invention also includes a method for delivering thrombolytic drugs to a thrombus.
• the method includes providing a sub-microcatheter that includes a unitary, flexible main body defining a lumen and having a distal end and a proximal end and a mandril positionable within the lumen and moveable throughout the lumen of the main body.
• the method also includes a step of transporting the sub-microcatheter to a thrombus site within a microcatheter and moving the sub-microcatheter-mandril as a unit within the microcatheter and placing adjacent the thrombus. The sub-microcatheter-mandril unit is then moved so that the sub-microcatheter is within the thrombus.
• the mandril is then removed from the sub-microcatheter in order to infuse drugs into the thrombus through the sub-microcatheter and through the micro-catheter.
• the present invention additionally includes a method for improving steerability and trackability of a sub-microcatheter.
• This method includes providing a sub-microcatheter that comprises a unitary, flexible main body that defines a lumen, the main body having a distal end and a proximal end.
• a mandril is positioned within the lumen of the main body at the proximal end and extends to the distal end.
• the mandril is moveable within the lumen in order to optimize pushability and trackability so as to advance the sub-microcatheter and the microcatheter to a treatment site.
• the present invention additionally includes a method for altering the flexibility of the sub-microcatheter by changing the diameter and flexibility of a mandril moveable within a lumen of the sub-microcatheter.
• sub-microcatheter flexibility is greater at the distal end for traversing tortuous blood vessels and is more rigid at the proximal end for operator control.
• the mandril is removable from the sub-microcatheter in order to allow for infusion of lytic drugs.
• Figure 1 is a side view of one embodiment of the sub-microcatheter of the present invention.
• Figure 2 is a side view of the sub-microcatheter of the present invention positioned within a thrombus.
• Figure 3 is a side view of a mandril that is positionable within the sub- microcatheter.
• Figure 4a is a schematic view of a microcatheter position with respect to a thrombus.
• Figure 4b is a schematic view of the position of the sub-microcatheter with respect to a thrombus and the microcatheter.
• the sub-microcatheter of the present invention illustrated generally at 10 in Fig. 1 includes a flexible main body 12 defining a lumen 33 with a distal end 14 and a plurality of ports 18a, b, and c, positioned proximally to the distal end 14, the main body 12 further terminating in a proximal end 20 opposing the distal end 14.
• the sub-microcatheter 10 encloses a mandril 22 within the lumen 33.
• the mandril 22 shown in Fig. 3 includes a shaft 24 and a taper section 26 extending distally from the shaft 24.
• the sub-microcatheter main body 12 further includes marker bands 29 a and b, positioned adjacent each of the ports 18a and c.
• the marker bands 29a and b enable an individual, such as a physician, positioning the sub-microcatheter 10 to precisely position the main body 12 within a thrombus such as is shown in Fig. 4b.
• the sub-microcatheter main body 12 is constructed utilizing a single extrusion of a polymer.
• the polymer is a high density polyethylene.
• the sub- microcatheter main body 12 is made of a material such as polypropylene, ethylene vinyl acetate (EVA), nylon or polyimide. With these materials of construction, the main body 12 has a uniform flexibility and rigidity throughout its entire length. In a preferred embodiment, the main body 12 is extruded so that the diameter and wall thickness as well as the polymeric material of construction render the main body 12 highly flexible with very little rigidity.
• the mandril 22 which is preferably made of a metallic material such as Nitinol, super elastic Nitinol, stainless steel, or a cobalt chromium alloy such as Elgiloy manufactured by Elgiloy Corp. of Elgin, Illinois, imparts a reversible and variable rigidity and flexibility to the main body 12 of the sub-microcatheter 10.
• a metallic material such as Nitinol, super elastic Nitinol, stainless steel, or a cobalt chromium alloy
• Elgiloy manufactured by Elgiloy Corp. of Elgin, Illinois
• One typical composition of Elgiloy includes 40% cobalt, 20% chromium, 15% nickel, 7% molybdenum, 2% manganese, 0.15% carbon, 0.04% beryllium with the remaining weight percent being iron. Further information on Elgiloy is described in U. S. Patent No. 2,524,661, which is incorporated herein by reference.
• the mandril 22 also imparts to the main body 12 the variable flexibility and rigidity required to advance the sub-microcatheter 10 through a microcatheter and a blood vessel.
• the flexibility and rigidity optimizes steerability and pushability of the sub-microcatheter 10 through an anatomy of a living being.
• the mandril 22 is removed, leaving the highly flexible sub-microcatheter main body positioned within an artery or vein.
• lytic drugs are delivered through the ports 18a-c. The lytic drugs act to disperse and dissolve a thrombus or blood clot.
• the sub-microcatheter 10 is also usable in a selective angiography procedure.
• the sub-microcatheter 10 of the present invention fits within a conventional microcatheter 50 as shown in Figure 2 and 4b.
• the microcatheter 50 provides to a physician a guide catheter that facilitates advancement and placement of the sub-microcatheter 10.
• the sub-microcatheter of the present invention 10 is advanced to the treatment site after the microcatheter is advanced to a position adjacent to the treatment site as shown in Fig. 4a.
• the microcatheter is advanced along a guidewire in a conventional manner.
• the sub-microcatheter 10 does not require a separate guidewire for positioning.
• Advancement of the sub-microcatheter 10 and the mandril 22 is accomplished by moving the metallic mandril 22 to the distal end 14 of the sub-microcatheter 10.
• the sub-microcatheter' s distal tip 14 is sealed shut so that the mandril 22 can transmit push forces through the sub- microcatheter 10 which is advanced to a treatment site as a single unit through the microcatheter 50.
• the mandrel includes a blunt tip which is radiopaque for fluoroscopic guidance.
• the mandril 22 is coated with a lubricious agent such as a silicone oil, a hydrogel or other hydrophilic coating in order to render the mandril 22 easier to manipulate.
• the sub-microcatheter 10 is also, in one embodiment, coated with a lubricious coating such as silicone oil, hydrogel, or other hydrophilic coating.
• the coating preferably covers a distal section of about 20 centimeters of the submicrocatheter where the catheter is reduced in diameter to a range of 0.014 inches to 0.016 inches. Microcatheters tend not to be very steerable. As a consequence, torque transmission from a proximal end to a distal end of the microcatheter is either severely limited or non-existent.
• the sub-microcatheter 10 of the present invention overcomes this significant problem by placement of the mandril 22 within the sub-microcatheter thereby rendering the sub-microcatheter steerable and pushable. It is contemplated that the submicrocatheter may be steered by use of a steerable guidewire in the submicrocatheter lumen in place of the mandrel.
• the steerable guidewire has a diameter of about 0.010 inches to 0.012 inches.
• the distal 5 centimeters of a submicrocatheter embodiment with a mandrel in the lumen has a flexibility that is equivalent to a 0.014 inch steerable guidewire.
• the sub-microcatheter 10 of the present invention is inserted after the conventional microcatheter accesses the artery and is positioned adjacent to the thrombus.
• the sub-microcatheter 10 is supported by the conventional microcatheter while the thrombus is being penetrated.
• the mandril 22 is removed and infusion of drugs is begun as is shown in Fig. 2.
• lytic drugs may also be infused through the conventional microcatheter to provide for an increased volume of lytic drug at the thrombus.
• the mandril 22 extends beyond the proximal end of the submicrocatheter 10 so that the mandril 22 is gripable by a physician.
• the mandrel has a maximum diameter that is preferably about 0.012 inches, which is tapered over a distal length of 20 centimeters to 0.004 inches in diameter.
• One mandrel embodiment terminates in a blunt tip.
• the blunt tip diameter is greater than the adjacent 0.004 inch tapered section and is preferably about 0.008 inches in diameter.
• a Luer tapered fitting of the submicrocatheter 10 includes a pair of finger grip wings 25a and 25b as shown in Fig. 1 that enable a user, such as a physician to adequately grip the Luer tapered fitting and lock accessory devices such as hemostatic valves and infusion devices to the Luer tapered fitting.
• the lumen of the tapered fitting facilitates an effortless loading of the mandril 22 in the sub-microcatheter main body lumen.
• the mandril 22 is loaded and positioned within the lumen in a manner that permits the physician to rotate and torque the mandril 22 and to steer the distal tip 14 of the sub-microcatheter 10 without hindering pushability or steerability.
• Between the submicrocatheter and the mandrel is an annular space that is preferably about 0.002 inches to aid in pushability and also steerability by the mandrel.
• the submicrocatheter tip is steerable by rotating the mandrel within the catheter lumen.
• the mandrel is locked to the submicrocatheter at the proximal end with a Touhy-Borst fitting.
• the catheter assembly is rotated as a unit.
• the tip of the catheter is also deflected for steering by axially pushing on the mandrel against the closed distal tip.
• the holes 18a-c defined by the main body 12 are in one embodiment equally spaced around the main body 12 about 90° apart.
• the infusion holes 18 a-c are about 0.005 inches in diameter.
• the holes are smaller than the blunt tip of the mandrel in order to prevent the mandrel from exiting the submicrocatheter through the infusion hole.
• marker bands are embedded in the catheter lumen adjacent to the infusion holes 18 a-c.
• the sub-microcatheter 10 is shaped so that the main body portion defining the holes 18a-c may be inserted directly into a thrombus 28 as shown in Figs. 2 and 4b. Once the main body 12 is inserted into the thrombus 28, drugs may be infused through the holes 18a-c.
• the submicrocatheter 10 includes a pinhole 16 at the end of the submicrocatheter.
• the main body 12 of the sub-microcatheter is made of a material such as high density polyethylene 12.
• the main body 12 has a wall thickness of about 0.002 inches.
• the submicrocatheter has a diameter, preferably, of about 0.018 inches or smaller.
• the lumen diameter defined by the main body is about 0.014 inches, minimum. It is understood, however, that the main body may be sized to have other dimensions. It is important that the diameter allows the sub-microcatheter 10 to easily navigate within a conventional microcatheter through a blood vessel.
• the main body 12 of the sub-microcatheter 10 is capable of safely penetrating the length of the thrombus creating a channel within the thrombus to infuse drug throughout the thrombus. This feature provides for greater surface contact of the drug with the thrombus and produces an open channel for blood flow that improves the effectiveness of the lytic process.

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• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
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• Engineering & Computer Science (AREA)
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• 1998
  • 1998-10-07 JP JP2000518728A patent/JP2001521796A/ja active Pending
  • 1998-10-07 AU AU97904/98A patent/AU9790498A/en not_active Abandoned
  • 1998-10-07 CA CA002304781A patent/CA2304781A1/en not_active Abandoned
  • 1998-10-07 WO PCT/US1998/021135 patent/WO1999022798A1/en not_active Application Discontinuation
  • 1998-10-07 EP EP98952135A patent/EP1032450A1/de not_active Withdrawn

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