WO2003039628A2

WO2003039628A2 - Balloon catheter with non-slip balloon

Info

Publication number: WO2003039628A2
Application number: PCT/US2002/036347
Authority: WO
Inventors: Robert C. Farnan; Andrew M. Green
Original assignee: Novoste Corporation
Priority date: 2001-11-09
Filing date: 2002-11-12
Publication date: 2003-05-15
Also published as: WO2003039628A3; AU2002352660A1

Abstract

The present invention is of a dilatation balloon (20) having surface characteristics (22,32) for reducing the potential for slippage of the inflated balloon with respect to the vessel wall being treated. The balloon (20) includes a series of elongated, ribbed protrusions (22,32) molded therein. The ribbed protrusions (22) are arranged in a crisscross pattern and create points of intersection (26) along the working length of the balloon (20). These points of intersection (26) provide interference between the balloon (20) and the vessel as they come into contact during inflation, and the increased interference provides for a reduction in the potential of balloon slippage while inflated in a vessel. Additional embodiments of the present invention call for a balloon (20) with one ribbed protrusion (32) spiraled in a spring coil pattern and balloons having alternate surface characteristics, such as bumps, knurls, ridges, dimples, cords, and raised areas.

Description

BALLOON CATHETER WITH NON-SLIP BALLOON

Robert C. Farnan Andrew M. Green

Field of Invention

The present invention relates to dilatation balloon catheters of the type employed in percutaneous transluminal angioplasty procedures, and more particularly to dilatation balloons that have a reduced potential of slippage relative to the vessel wall or lesion when inflated in a vessel.

Background of Invention

Typically, a PTA (percutaneous transluminal angioplasty) or PTCA (percutaneous transluminal coronary angioplasty) catheter is used to carry a dilatation balloon to a treatment site, where pressurized fluid is supplied to the balloon to expand the balloon against a stenotic lesion, which is characterized by the build-up of plaque. When an angioplasty balloon is inflated and forced into contact with the plaque, the balloon can have a tendency to move or slip longitudinally in relation to the lesion or the vessel wall being treated. This movement during dilatation can add injury to the lesion and more importantly, can injure healthy tissue on either side of the lesion. PTA and PTCA balloons that are currently available in the market are designed with a smooth, homogenous surface, and the combination of a smooth balloon surface and the wet environment of a blood vessel creates this potential for balloon slippage. Additionally, when the balloon expands and forces against a more complex lesion (calcified lesion and in-stent restenosis), the lesion is less pliable and the forces exerted back on the balloon can be great enough to cause the balloon to shoot out of the lesion area.

Cutting balloons (atherotomy) have recently shown clinical efficacy in preventing the reoccurrence of some types of restenosis (specifically calcified lesions and in-stent restenosis). The cutting balloon is a coronary dilatation catheter with 3 to 4 atherotomes (microsurgical blades) bonded longitudinally on the balloon surface. As the cutting balloon is inflated, the atherotomes move radially and open the occluded artery by incising and compressing the arterial plaque in a controlled manner. An additional advantage of the cutting balloon is that it maintains its position during inflation by using the metal blades on the external surface of the balloon to penetrate into the tissue and prevent the balloon from moving in relation to the vessel during the dilatation procedure.

The primary objective of the present invention is to provide a PTA or PTCA catheter with a non-slip balloon, a balloon with a reduced potential of slipping relative to the vessel wall during the dilatation procedure and further, to provide the advantage of a non- slip balloon without cutting blades or other penetrating means that may severely injure the vessel. The PTA or PTCA balloon is to maintain its initial position during the dilatation procedure.

Additional objects of this invention are to provide for better controlled dilatation and gripping of vessel during an angioplasty procedure.

Another object of the invention is a balloon with surface characteristics to reduce balloon slipping or longitudinal movement relative to the vessel during dilatation. The surface of a balloon can be textured with bumps, knurls, ridges, dimples, cords, raised areas, spirals, etc. arrange in any possible pattern. A further object is to provide such balloons which, because of their exterior features, can be used in angioplasty procedures with a greater probability of success. A further object of the invention is to provide such balloons with surface characteristics molded therein.

It is also an object of this invention to provide balloons that, in addition to having characteristics that reduce the potential of balloon slippage relative to the vessel, exhibit physical properties, for example, toughness, flexibility and tensile strength, exhibited by balloons known in the art.

These and other objects will become apparent from the following discussion of the invention.

Brief Description of the Drawings

Fig. 1 is a perspective view of an angioplasty balloon catheter incorporating a non-slip balloon according to the present invention.

Fig. 2 is a perspective view of the non-slip balloon in its expanded state.

Fig. 3 is a perspective view showing a further embodiment of the present invention.

Figs. 4a-h are top and side views of alternate embodiments of the non-slip balloon of the present invention.

Detailed Description of Invention

The present invention relates to balloons for percutaneous transluminal angioplasty (PTA), wherein a catheter with a balloon at the distal end is positioned within a bodily vessel or conduit and inflated to expand the vessel or conduit. Percutaneous transluminal coronary angioplasty (PTCA) catheters are well known for their utility in treating stenosis, or the build-up of plaque, and other occlusions in coronary blood vessels.

The dilatation catheter 10 incorporates a balloon 20 having surface characteristics that will prevent the balloon movement in relation to the vessel when the balloon is inflated during an angioplasty procedure. More specifically, a preferred embodiment of the present invention is shown in Figure 1. Figure 1 displays a PTCA catheter 10 (could be a PTA catheter as well) with a unique balloon 20 having ribbed protrusions 22 incorporated therein.

The catheter 10 includes a shaft 12 having a proximal section 14, a distal section 16 and an intermediate section 18 therebetween. The distal end of the distal section 16 may include a taper and be slightly smaller in diameter than the rest of the shaft 12. A dilatation balloon 20 is affixed to the distal section 16 of the catheter shaft 12, and a luer hub 13 for insertion of the guide wire (not shown) and connection of an inflation media (not shown) is located at the proximal end of the catheter 10. Extending distally a short distance from the proximal end of the catheter 10 and retained at one end by the luer hub 13 is a strain relief tube 15to prevent kinking of the catheter portion that remains outside the patient and is most susceptible to stresses and bends.

The catheter 10 can be of a coaxial design having an inner tube with a guide wire lumen and an outer tube with a balloon inflation lumen or can be composed of a multi-lumen tube having both guide wire and balloon inflation lumens extruded within a single tube. In both the coaxial and multi-lumen catheter platforms, the inflation lumen is fluidly connected to the balloon 20 for the introduction/removal of inflation media for the inflation and deflation of the balloon 20 attached to the distal end of the catheter shaft 12. Any of the inner, outer or multi-lumen tube can be composed of up to three layers of material and can be reinforced with braids. If different flexibility and stiffness regions are desired along the length of the catheter shaft 12, multi-durometer tubing and other variable stiffness technology, such as co-extrusion tapering techniques, can be used. The catheter 10 shall be compatible with standard guide catheters or introducer sheaths.

The dilatation balloon 20 of the present invention incorporates a knurled surface for increased interference between the balloon 20 and the vessel wall or lesion so as to maintain the balloon 20, as initially placed by the ftiterventional Cardiologist, at the lesion to be treated. The preferred knurled surface is a series of raised ridges or ribs 22 in a crisscross or braid like pattern molded into the working length 24 of the balloon, as seen in Figure 2. The crisscross surface pattern of the balloon 20 shown in Figure 2 is a result of four integrated ribs 22 spiraled around the perimeter of the balloon 20. Each integrated rib 22 begins at one end of the balloon working length 24 and ends at the other end of the balloon working length 24. The balloon molded ribs 22 have identical coil pitches, but each of their starting points are radially spaced 90 degrees apart at one end of the balloon working length 24, and each of their ending points are radially spaced 90 degrees apart at the other end of the balloon working length 24. The elongated ribs 22 intersect to create X's radially and longitudinally along the working length 24 of the balloon 20. The points of intersection 26 are preferably spaced 10 mm apart along each individual plane and 5 mm apart in different planes. The spacing or pitch does not necessarily change with balloon length; there will just be more crisscrosses and points of intersection 26 with longer balloon lengths. These points of intersection 26 are most crucial in creating interference between the balloon 20 and the vessel as they come into contact during inflation. This increased interference reduces the potential of balloon slipping while inflated in the vessel. The crisscross intersections can be spaced closer together to create more points of intersection 26 and thus, increased interference to reduce balloon slipping. The points of intersection 26 may also create natural folds in the balloon 20 for neatly folding the deflated balloon 20 around the catheter shaft 12.

The "knurl" pattern may range from as close as .1 inch up to 1 inch in spacing. The preferred depth (protrusion) of "knurl" is from .005 inch to .015 inch with a phase φ ranging from .010 inch to .030 inch.

Any of 1, 2, 4, 8, and 16 integrated rib members 22 may be spiraled around the periphery of the balloon 20. One member will create a spring coil pattern 32 as seen in Figure 3. Two rib members will be spaced 180 degrees apart, eight rib members will be spaced 45 degrees apart and sixteen members will be spaced 22.5 degrees apart.

Dilatation balloons can be made from a variety of known materials and can be fabricated to be assembled on either a coaxial or multi-lumen catheter platform. Considerable art is already available on the use of balloon catheters and their fabrication. The preference for material selection is along the line of a high pressure, non-compliant material (such as PET or polyethylene terrathalate) or a semi-compliant, puncture resistant material (such as nylon). A tacky coating (such as urethane) may be applied to the outer surface to enhance the frictional coefficient and aid in the deflation of the balloon. The coating can be selectively added to certain areas of the balloon, such as just the ribs.

The balloon 20 can be a multi-layered balloon with a non-compliant inner layer to a most compliant outer layer. For example, there may be a most inner layer of PET, which provides a higher pressure balloon, surrounded by an outer layer of nylon, which provides a more puncture resistant surface. Ribs are not separate layer unless separate member adhered to balloon surface. For tackiness, urethane can be added as a top layer in multi-layered blowing.

The balloon 20 may be from 1.5-12 mm in diameter (1.5 - 4 mm for coronary and 4-12 for peripheral vessels) (the diameter of the balloon 20 is the minor diameter of the balloon 20 and does not include the ribs 22 in the dimension) and 15-60 mm in length (15-40mm for coronary and up to 60mm for peripheral vessels). The balloon inflation pressure will be form 8-20 atmospheres depending on the wall thickness of the balloon 20.

The dilatation balloon 20 is made using conventional balloon molding operations and additional pre and post molding operations. In general, the balloon making process includes (1) extruding a tubular parison of the chosen balloon material or materials; (2) positioning the tubular parison of material into a blow molding machine and conducting the blow molding operations, which include (a) heating the tubular parison of material to a certain transition temperature and longitudinally expanding or stretching the tubing; (b) inflating the balloon within the mold, which defines the dimensions and certain physical characteristics of the balloon; (c) possibly more longitudinal expanding of the balloon; (d) having the balloon reach its crystallizing temperature for effectively locking the molecular structure in place; and (e) cooling down the mold and the balloon inside the mold. The surface characteristics of the balloon take the shape of the mold.

The dilatation balloon 20 is affixed to the distal section 16 of an elongated flexible tubular catheter 10. When the balloon 20 is expanded, its working length 24, i.e., its medial section, exhibits a diameter substantially larger than that of the catheter shaft 12 on which it is mounted. The proximal and distal stems 28 and 29 of the balloon 20 have diameters substantially equal to the diameter of the catheter body. Proximal and distal tapered sections 30 and 31, referred to herein as "spheres" or "cones", join the medial section 24 to the proximal and distal stems 28 and 29, respectively. Each sphere or cone diverges in the direction toward the medial section 24. Fusion bonds or UN adhesives between the proximal and distal balloon stems 28 and 29 and the catheter form a fluid- tight seal to facilitate dilation of the balloon 20 when a fluid under pressure is introduced into it, via an inflation port formed through the wall of the catheter and in fluid communication with the inflation lumen of the catheter.

The balloon 20 can be molded to have other surface characteristics, such as small spheres, dimples, elongated rods, spirals, and cords, that will increase friction or interference between the balloon 20 and the vessel and reduce balloon slipping.

Alternatively, the raised surface characteristics may be created in the balloon material itself through the addition of carbon or Kevlar fibers in the material matrix.

Another alternative can be seen in Figure 4 and has elements of certain shapes, such as spheres or rods, trapped between the balloon material layers.

Claims

WHAT IS CLAIMED:

1. A dilatation balloon for positioning within a bodily vessel or conduit and inflating to expand the vessel or conduit, comprising: a proximal end; a distal end; a medial section connecting said proximal end to said distal end and comprising surface characteristics that reduce slipping or longitudinal movement of the balloon relative to the vessel or conduit.

2. A dilatation balloon for dilating a human vessel comprising: a proximal end; a distal end; a medial section connecting said proximal end to said distal end and comprising a textured surface that provides for less slipping or longitudinal movement of the balloon relative to the vessel.

3. A dilatation balloon for dilating a human vessel having surface characteristics for reducing the potential for slippage of the inflated balloon with respect to the vessel wall being treated, said balloon comprising: a proximal end; a distal end; a medial section connecting said proximal end to said distal end and comprising a series of elongated, ribbed protrusions molded therein.

A dilatation balloon for dilating a human vessel having surface characteristics for reducing the potential for slippage of the inflated balloon with respect to the vessel wall being treated, said balloon comprising: a proximal end; a distal end; a medial section connecting said proximal end to said distal end and comprising at least one elongated, ribbed protrusion molded therein.

The dilatation balloon of claim 3 wherein said elongated, ribbed protrusions spiral around the balloon and intersect with each other to create multiple points of intersection radially and longitudinally along the medial section of the balloon.