ANGIOGRAPHIC CATHETER FOR USE WITH RETROGRADE BLOOD FLOW

A catheter that is configured to achieve high velocity injections of contrast solution that will not readily wash out in retrograde blood flow. The distal end of the catheter can include a plurality of fluid outlet openings. The fluid outlet openings are spaced circumferentially around the circumference of the catheter and the fluid outlet openings have ejection axes that are angled in a direction toward the distal end so that a velocity component of the ejected contrast solution is against or opposite the retrograde blood flow.

FIELD

This disclosure relates generally to a catheter for injecting a fluid into a patient. In one specific implementation, the catheter can be an angiographic catheter for injecting a contrast solution into retrograde blood flow within a vessel of a patient during an imaging procedure or an interventional procedure requiring imaging.

BACKGROUND

Angiographic catheters are well known in the medical field. Angiographic catheters are typically used to inject contrast solution into a vessel of a patient during an endovascular procedure on the patient. Since blood is not visible using imaging technologies such as fluoroscopy (or x-ray), the contrast solution is used to produce a dark image on the screen of the imaging technology being used.

Most standard angiographic catheters are single lumen devices with a fluid outlet opening at the distal end. Some angiographic catheters may have a plurality of small fluid outlet openings located near the distal end of the catheter.

When injecting contrast solution into retrograde (i.e. reverse) blood flow in the vessel with standard angiographic catheters, there is quick washout of the contrast solution. That is, even when used with pressure injectable contrast solution injectors, the contrast solution does not exit the tip of the catheter with enough velocity into the retrograde blood flow and thus the contrast solution washes out quickly from the image resulting in either additional or excessive contrast solution usage, which can be harmful to the patient, or resulting in an unusable image due to lack of contrast solution. In addition, this makes it difficult to accurately image anatomy that is distal to the catheter tip, including, but not limited to, the aortic root during transcatheter aortic valve implantations.

SUMMARY

A catheter is described that is configured to achieve high velocity injections of contrast solution that will not readily wash out in retrograde blood flow. The catheter can be an angiographic catheter that is configured for injecting a contrast solution into retrograde blood flow within a vessel of a patient during an imaging procedure or any vascular intervention requiring imaging. However, the catheter can be configured for use in other applications where high velocity injections of a solution into a retrograde blood flow are desired.

In one embodiment described herein, the distal end of the catheter includes a plurality of fluid outlet openings in an injection lumen that place a fluid passageway of the injection lumen in fluid communication with an exterior of the injection lumen. The fluid outlet openings are spaced circumferentially around the circumference of the injection lumen, and the fluid outlet openings have ejection axes that are angled in a direction toward the distal end so that a velocity component of the ejected contrast solution is against or opposite the retrograde blood flow.

In another embodiment, the catheter can include a catheter body having a distal end portion with a tip, and a fluid passageway extending through the catheter body to the tip. Axial fluid outlet openings are formed in the tip, where the axial fluid outlet openings extend from the fluid passageway through the tip to place the fluid passageway in fluid communication with an exterior of the catheter body. The axial fluid outlet openings are spaced circumferentially around the circumference of the tip, and the axial fluid outlet openings have ejection axes that are parallel to a longitudinal axis of the catheter body.

In another embodiment, the catheter can include the angled fluid outlet openings in combination with the axial fluid outlet openings.

DETAILED DESCRIPTION

Referring toFIGS. 1A and 1B, an embodiment of a catheter10described herein is illustrated.FIG. 1Aillustrates a proximal end portion12of the catheter10whileFIG. 1Billustrates a distal end portion14of the catheter10. The catheter10has a catheter body16formed from any suitable material used to form conventional catheters. A fluid passageway18(seen inFIGS. 3 and 4) or lumen extends from the proximal end portion12toward and to the distal end portion14. The catheter10is configured to achieve high velocity injections of contrast solution that will not readily wash out in retrograde blood flow. In one embodiment, the catheter10can be an angiographic catheter that is configured for injecting a contrast solution into retrograde blood flow within a vessel of a patient during an imaging procedure. However, the catheter10can be configured for use in other applications where high velocity injections of a contrast solution into a retrograde blood flow are desired.

Referring toFIG. 1A, the proximal end portion12of the catheter10includes a luer fitting hub22and a strain relief section24both of which are well-known in the art. However, other configurations of the proximal end portion12are possible. The luer fitting hub22can be formed from polycarbonate, HDPE, polypropylene, and other known materials. The strain relief section24can be a hard-molded plastic or a soft elastomer like the tip discussed further below.

Referring toFIG. 1B, the distal end portion14includes a series of small fluid outlet openings26formed through the catheter body16that place the fluid passageway18in fluid communication with the exterior of the catheter body16. The fluid outlet openings26run in a series along a section of the distal end portion14and are arranged circumferentially around the circumference of the distal end portion14of the catheter body16. InFIG. 1B, the fluid outlet openings26are illustrated as being arranged in a plurality of linear series, for example 4 linear series, spaced circumferentially around the circumference of the catheter body16. However, other arrangements of the fluid outlet openings26are possible. For example,FIG. 6illustrates an embodiment of the distal end portion14of the catheter where the fluid outlet openings26are arranged in a plurality of helical series around the catheter body16.

Referring toFIGS. 2 and 3, the fluid outlet opening26described herein further have ejection axes (EA) that can be described as being angled in a direction toward a distal end28of the distal end portion14or of the catheter body16, or described as being disposed at an acute angle α from the longitudinal axis of the catheter. The angled fluid outlet openings26create high velocity fluid flow of fluid (illustrated by arrows inFIG. 3), such as contrast solution, that is ejected through the fluid outlet openings26with a velocity component that can be described as being axial or against or opposite retrograde blood flow (BF) within a vessel of a patient. This axial velocity component helps to create longer lasting contrast during an imaging procedure. The acute angle α can be any angle that achieves the desired axial velocity component. The fluid flow exiting the openings26also has a radial velocity component that is perpendicular to the axial velocity component. In one embodiment, the acute angle α can be from about 10 degrees to about 75 degrees. In another embodiment, the acute angle α can be from about 30 degrees to about 50 degrees.

The fluid outlet openings26can also be described as being holes, slots, apertures, orifices, and the like. The fluid outlet openings26can have any suitable shapes (or mix of shapes) as long as the desired axial velocity component can be achieved. Examples of shapes include, but are not limited to, circular, oval, triangular, square, rectangular, pentagonal, hexagonal, septagonal, dodecagonal, star-like, lightning bolt, and the like.

FIGS. 2 and 3show the fluid outlet openings26as having constant dimensions from an inner surface30to an outer or exterior surface32. However, other variations are possible. For example, the fluid outlet openings26can be tapered.FIG. 4illustrates an example where the fluid outlet openings26taper outwardly or up so that a size d1of the openings26at the inner surface30is less than a size d2of the openings26at the outer surface32.FIG. 5illustrates an example where the fluid outlet openings26taper inwardly or down so that the size d1of the openings26at the inner surface30is greater than the size d2of the openings26at the outer surface32.

Returning toFIGS. 1B and 2, in one embodiment, the fluid outlet openings26can start a distance X or closer from the proximal end of the tip40or the boundary between where the tip40begins and the catheter body16. In one non-limiting embodiment, the distance X can be about 0.5 inches or less.

FIGS. 1B and 2also illustrate a soft tip40disposed at the distal end28of the distal end portion14or the catheter body16. The soft tip40forms a soft, atraumatic tip. The use of a soft, atraumatic tip on a catheter is well known. The soft tip40is further designed to allow passage of a guidewire therethrough while preventing the contrast solution from exiting through the soft tip40when the contrast solution is injected with high velocities, for example around 1200 psi.

The tip40is illustrated in the drawings, such asFIGS. 1B and 2, as being straight from one end thereof to the other end. However, the tip40can have other shapes including, but not limited to, a pigtail shape, a hook shape, a helical shape, or other non-straight shape.FIG. 15illustrates one non-limiting example of the tip40having a non-straight shape, in this example a pigtail shape. If a non-straight tip is used, the non-straight tip can maintain its non-straight shape unless a guidewire is inserted through the lumen through the tip thereby straightening the tip.

The tip40can be made of any soft elastomeric material(s) suitable for the functions to be performed by the tip40. Examples of suitable materials include, but are not limited to, soft polymers such as silicone, polyurethane, high-density polyethylene (HDPE), low-density polyethylene (LDPE), Pebax, or other elastomeric material. In one non-limiting example, the tip40can have a durometer of anywhere from about Shore 20A to about Shore 70D.

Referring toFIGS. 7A and 7B, another embodiment of a catheter50is illustrated. In this embodiment, the catheter50includes an inner lumen52and an outer lumen54(or fluid passageway) for fluid flow. The inner lumen52serves as a guidewire lumen through which a guidewire can pass and the outer lumen54forms an injection lumen through which the contrast solution passes before being ejected from the fluid outlet openings26. This allows for controlled flow of the contrast solution without interaction with the guidewire, with the contrast solution being contained in the outer lumen52. The fluid outlet openings26can have a configuration similar to the fluid outlet openings26described above forFIGS. 1-6.

Only the distal end portion14of the catheter40is illustrated inFIGS. 7A and 7B. The proximal end can have a configuration similar to the proximal end12inFIG. 1Aor have a different configuration. The inner lumen52is formed by an inner catheter body56disposed within, for example concentrically, the catheter body16. The outer lumen54is formed between the catheter body16and the inner catheter body56. The inner catheter body56can be continuous without openings or holes so that the contrast solution in the outer lumen54cannot flow into the inner lumen52.

The catheter50further includes the tip40. The tip40can be secured to the inner catheter body56or to the catheter body16. The tip40can be made of elastomeric material as described above. However, in one embodiment, the tip40can have a hard proximal section (i.e. a larger durometer than the distal section of the tip) to bond to the distal end of the inner catheter body56or to the distal end of the catheter body16. If the tip40has a non-straight shape, for example as illustrated inFIG. 15, the tip40can be bonded to either the end of the inner catheter body56, to the end of the catheter body16, or to the ends of both of the catheter bodies16,56. In one embodiment, if a non-straight tip is used, the non-straight tip may have only one lumen for the guide wire, with fluid flow being restricted to the outer lumen only. However, in other embodiments, fluid may also flow through the inner lumen and ultimately through the tip.

Referring toFIG. 13, the catheter body16described herein can have a construction suitable for supporting the high pressure of the contrast solution to be injected. For example, in one non-limiting embodiment, the catheter body16can be braided with a strengthening material60including but not limited to, stainless steel, titanium, nitinol, and other material to support the high pressure. In addition, the fluid outlet openings26can be braided or cut around or circumventing the braiding. In addition, the catheter body16and/or the fluid outlet openings26can be coated with a hydrophobic coating.

A general method of construction of the catheter10is to extrude the catheter body16from a standard nylon, polyethylene, PTFE, PFA, Pebax, or others. The catheter body16can then be reflowed over PTFE and braiding. The braiding can be stainless steel, titanium, nitinol, or aluminum. The fluid outlet openings26can then be laser cut using a laser placed at an angle to create the desired acute angle α. The tip40is then over-molded or bonded on the distal end28. The luer fitting hub22and the strain relief24are then over-molded or bonded on to the proximal end of the catheter body16.

In some embodiments, the catheter can include axial fluid outlet openings for the contrast solution either by themselves or in combination with the fluid outlet openings26. The axial fluid outlet openings would eject the contrast solution into the retrograde blood flow with a velocity component that is substantially entirely axial.

FIGS. 8-10illustrate an embodiment of a catheter70with axial fluid outlet openings72.FIGS. 8-10illustrate just a distal end portion74of the catheter70. The proximal end portion can have a configuration similar to the proximal end portion12or have a different configuration. In this embodiment, the catheter70includes a tip76that can have a construction that is similar to the tip40or the tip76can be non-straight as described above and as illustrated inFIG. 15. A metal or plastic insert78that is similar in construction to an apple core device, is placed in the tip76. The insert78includes a center hub80, an outer wall82, and a plurality of ribs84extending between the center hub80and the outer wall82, with the spaces between the ribs84forming the fluid outlet openings72that are spaced circumferentially from one another. The center hub80allows passage of a guidewire86, and an optional strain relief88can be provided that extends from the center hub80. The axial fluid outlet openings72create straight fluid flow out the tip76that is completely (or substantially completely) axial in a direction opposite the retrograde blood flow. In this embodiment, the ejection axes of the axial fluid outlet openings72are parallel (or substantially parallel) to the longitudinal axis of the catheter70. The axial fluid outlet openings72may be present in both a straight tip, like the tip40, or in a non-straight tip that has been straightened by a guidewire.

Referring toFIGS. 11 and 12, another embodiment of a catheter90with axial fluid outlet openings92in a straight tip96is illustrated.FIGS. 11-12illustrate just a distal end portion94of the catheter90. The proximal end portion can have a configuration similar to the proximal end portion12or have a different configuration. In this embodiment, the catheter90includes the tip96that can have a construction that is similar to the tip40. In another embodiment, the tip96can have a different shape, such as a pigtail shape, a hook shape, a helical shape, or other non-straight shape as illustrated inFIG. 15. A plurality of the axial fluid outlet openings92are formed in the tip96at circumferentially spaced locations through which contrast solution can be ejected completely (or substantially completely) axial in a direction opposite the retrograde blood flow. In this embodiment, the ejection axes of the axial fluid outlet openings92are parallel (or substantially parallel) to the longitudinal axis of the catheter90. A guidewire (not illustrated) can extend through a central passage or lumen100at the center of the tip96. The axial fluid outlet openings92may be present in both a straight tip, like the tip96, or in a non-straight tip that has been straightened by a guidewire.

FIG. 14illustrates another embodiment of an atraumatic tip110that is usable with any of the catheters described herein. The tip110can be used with a catheter having the angled fluid outlet openings, for example as described with respect toFIGS. 1-7. In addition, the tip110can be provided with the axial fluid outlet openings, for example as described with respect toFIGS. 8-12. In this embodiment, the tip110has an opening112for a guidewire, and a rounded lip114defining the opening112. The diameter of the opening112is less than the diameter of the guidewire extending therethrough during use. Therefore, there is an interference fit between the opening112and the guidewire. In addition, the rounded lip114will prevent the opening112from blowing open under the pressure of the contrast solution being injected as it will be a softer edge for the contrast solution to impinge against. In this embodiment, the rounded lip114is illustrated as being substantially continuously curved from a point116within the tip110where the lip114intersects an angled inner surface118of the tip110to a point120on the exterior of the tip110where the lip114intersects an angled outer surface122of the tip110.

Any of the catheter embodiments described herein can include a built-in side port and hemostatic valve each of which is known in the art. In addition, any of the catheters described herein can be made steerable (1-axis or 2-axes) in conventional manner to be able to adjust the tip, whether straight or non-straight, location in-vivo. Further, any of the catheters described herein could be configured to have multiple fluid passageways or lumens for multiple fluid injections, for example up to four fluid passageways. Further, any of the catheters described herein can have directional control of the ejected contrast solution where one or more of the fluid outlet openings described herein can be closed off to allow for directionally controlled fluid flow.