Technical Field:

This invention relates to catheters and more particularly to catheters which include multiple lumina and which have multiple balloons for defining a treatment chamber.

Background Art:

Blood vessels at certain critical parts of the human circulatory system can and often do become burdened with deposits, coatings, occlusions, etc., which can reduce the vessel's blood carrying capacity. In some patients, this reduced capacity can cause serious and permanent injury. As a result, when significant burden is found to exist, some form of medical intervention is often indicated.

A number of intervention techniques have been developed over the years. These techniques permit the removal or reduction of the burden so that an increased and healthier blood flow can result. When a normal flow cannot be restored by these methods, the burdened portions of the vessel are sometimes bypassed using a vessel taken from elsewhere in the body. When the original blood vessel is a coronary artery, the bypass procedure is referred to as a coronary artery bypass graft.

The bypass graft itself may in time become burdened, as was the original vessel, therefore requiring further intervention. One type of burden that is of particular concern in treatment of a bypass arises when a vein has been used to make the bypass graft. Venous grafts are particularly susceptible to deposits of a friable material which is easily loosened during an intervention. The friable

material is of a crumbly nature and pieces are easily dislodged from the inside of the bypass graft. Often a treatment site will include a high proportion of such friable material surrounding other types of burden. Under these circumstances, attempts to remove the other burden often result in much of the friable material breaking loose and entering the blood stream. This loosened biological debris can block the artery and cause myocardial infarction.

The intervention techniques referred to above include use of known devices such as balloon angioplasty, rotational atherectomy, the transluminal extraction catheter, stents, and the directional coronary atherectomy. Each of these techniques, and others, are favored by practitioners in the treatment of diseased saphenous vein grafts and other vessels. Yet, each of these techniques exposes a patient to some greater or lesser degree of risk of embolism. Unfortunately, this risk is present under the most carefully conducted intervention because the friable material can be so easily dislodged. This can happen even while merely positioning or repositioning a catheter device at a burdened region of the vessel.

What is needed is a device which can be used in conjunction with other treatment devices and will allow a successful removal of the friable material from the treatment region without increasing a risk of formation of emboli.

Disclosure of Invention:

It is an object of the present invention to provide a catheter device which will be used to stabilize a treatment site. A treatment site is "stabilized" by removing friable material from the vessel walls. and thus reducing the risk of embolization.

It is a further object of this invention to create a treatment chamber which is sealed off from the normal blood flow at a treatment site.

It is a further object of this invention to permit removal of the friable material at the treatment site and to do so within the sealed treatment chamber in order that loose material does not escape into the blood stream.

It is a further object of this invention to provide infusion and aspiration of

the sealed treatment chamber to aid in a safe removal of loosened material.

It is a further object of this invention to allow the introduction of medications to the treatment site by way of infusion, and to confine the medications to the sealed treatment chamber. It is a further object of this invention to permit use of the sealed and flushed treatment chamber by other catheter type treatment devices used to remove any other burden, such as discrete lesions, once the site is stabilized. Finally, it is an object of the present invention to reduce ischemic stress resulting from the sealing of a vessel by use of perfusion around the sealed treatment chamber. This object will allow the treatment chamber to remain in place for a prolonged intervention interval.

In accordance with the above objects and those that will be mentioned and will become apparent below, the treatment chamber catheter device of the present invention comprises a multiple lumen catheter for insertion into a biological conduit, the catheter comprising: a catheter member including multiple lumina and having proximal and distal ends; an expandable sealing member for sealing off fluid flow between the proximal and distal ends within the biological conduit defining a treatment chamber between the proximal and distal ends, the catheter member having a lumen for accessing the treatment chamber and for removing fluid and biological debris from the treatment chamber, whereby, an accessible, sealed treatment chamber is provided which retains loosened biological material for removal through the second lumen. In a preferred embodiment of the present invention, the expandable sealing member includes first and second expandable members, one expandable member being located distal to, the other located proximal to a treatment site. A treatment chamber being defined as the region within the vessel and located between the expandable sealing members. In another preferred embodiment, the catheter member includes a perfusion lumen having openings located proximal to and distal to the treatment

chamber. The perfusion lumen and openings allow blood to bypass the treatment chamber within the treated vessel, thus controlling ischemic stress.

In another preferred embodiment, the catheter member includes an independent infusion lumen having an opening into the treatment chamber, whereby a saline or flushing solution and the like can be introduced through the infusion lumen into the treatment chamber. The embodiment also includes a separate aspiration lumen having an opening into the treatment chamber, whereby fluids and biological debris may be removed through the aspiration lumen by suction. The treatment chamber catheter summarized above provides a fluid sealed treatment region to which access is gained via a catheter lumen. A variety of catheter-type treatment devices can be inserted into and removed from the treatment chamber. The treatment chamber, once established, can remain in place while such devices are introduced into the treatment chamber to treat or monitor the intervention. This can be accomplished without increasing the risk of additional trauma to the vessel, since the devices can be inserted through the larger access lumen.

Typical of the devices which can be used with the treatment chamber catheter are the angioscope, the ultrasonic transducer for imaging, and a variety of devices used to excise tissue.

Finally, one preferred embodiment replaces the expandable sealing members with a fine meshed screen located distal to the treatment site. The use of this screen allows the natural flow of the vessel's biological fluids without a need for a separate perfusion lumen, and prevents loosened biological material from entering the natural fluid flow.

It is an advantage of this invention to provide a treatment chamber catheter device which can be used in conjunction with a variety of other catheter type devices to stabilize a treatment site in saphenous vein graft disease. It is an advantage of this invention to provide a treatment chamber catheter device which can be used to apply and confine a medication to a specific treatment site.

It is an advantage of this invention to provide a treatment chamber catheter device which can be used in conjunction with a variety of other catheter type treatment devices to provide a sealed treatment chamber during an intervention and diagnosis. It is an advantage of this invention to provide an isolated treatment chamber for accommodating a variety of devices for vascular intervention and diagnosis.

It is a further advantage of this invention to enable the repeated insertion and removal of such devices while minimizing trauma to the biological conduit. It is a further advantage of this invention to prevent loosened material from entering the biological conduit's natural fluid flow.

Finally, it is an advantage of this invention to provide a perfusion bypass around the isolated treatment chamber for the natural fluid flow, thus reducing ischemic stress.

Brief Description of Drawings:

For a further understanding of the objects and advantages of the present invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawing, in which like parts are given like reference numerals and wherein:

Fig. 1 is a partial perspective view of the treatment chamber catheter in accordance with the present invention.

Figs. 2 through 6 are cross-sectional views taken through corresponding lines of Fig. 1. Figs. 7 through 10 are cross-sectional views corresponding to Figs. 2 through 5, respectively, and illustrate additional catheter lumen.

Fig. 11 is a partial perspective view of the perfusion lumen showing an in¬ line forced perfusion pump.

Fig. 12 is a cross-sectional view corresponding to Figs. 2 and 7 showing dual perfusion lumen.

Fig. 13 is a partial side view of the treatment chamber catheter having

the expandable sealing members replaced by a fine-meshed screen.

Fig. 14 is a partial perspective view of the treatment chamber catheter of Fig. 13 illustrating the screen in an extended position.

Fig. 15 is a partial perspective view of the treatment chamber catheter of Fig. 13 showing the screen in a retracted position.

Best Mode for Carrying Out the Invention:

Figure 1

The invention will now be described with respect to Fig. 1 , which illustrates the treatment chamber catheter shown generally by the numeral 10 in accordance with the present invention.

The words "proximal" and "distal" as used herein have the following meaning, the proximal end of the catheter device is the end associated with the operator of the device. The distal end is the end furthest from the operator. The phrases "blood vessel" and "biological conduit" are used interchangeably herein. Though typically the treatment chamber catheter 10 will be employed within a blood vessel, it should not be so limited. In general it can be used within any biological vessel or conduit of a body. Similarly the phrases "blood" and "biological fluid" are used interchangeably. The treatment chamber catheter 10 includes an elongated multiple lumen catheter member 12 having a proximal end shown generally by the numeral 14 and a distal end 16. The catheter member 12 has a first lumen 18 extending and terminating at the distal end 16 in an atraumatic lumen termination 32. A second lumen 20 of the catheter member 12 terminates in an opening 22. The catheter member 12 has two expandable sealing members 24, 26 which are attached to an outer surface 28 of the catheter member 12. A first expandable sealing member 24 is located proximally to the opening 22 of the second lumen 20. A second expandable sealing member 26 is located distally to the first expandable sealing member 24 and is attached to the outer surface 28.

A treatment chamber shown generally by the numeral 34 is created in the

region located between the first and second expandable sealing members 24, 26. The treatment chamber 34 is defined by the opening 22 of the second lumen 20 into the region located between the first and second expandable sealing members 24, 26. Access to the treatment chamber 34 is provided via the second lumen 20.

The distally extending first lumen 18 is used to bypass the biological fluid around the treatment chamber 34. The first lumen 18 has proximal perfusion openings 36 located proximally to the first expandable sealing member 24 and has distal perfusion openings 38 located distally to the second expandable sealing member 26 along the distally extending first lumen 18.

A guide wire 30 enters the distally extending first lumen 18 proximal to the first expandable sealing member 24. The guide wire 30 is carried within the distally extending first lumen 18 to the distal end 16. The guide wire 30 extends beyond the atraumatic lumen termination 32 for guiding the catheter 10 within a blood vessel or other biological conduit (not shown).

Typical Use

In a typical use of the present invention, a guiding catheter (not shown) is inserted and left in position during the remainder of the intervention. The use of a guiding catheter will be understood by those skilled in the art as useful to reduce trauma resulting from repeated insertions and removals of catheter devices, and to reduce the overall duration of the intervention. Typically, in the case of coronary vessels, the guiding catheter will extend distally from a point of insertion at the groin into the aorta. Once the guiding catheter is in place, the treatment chamber catheter 10 is inserted through the guiding catheter, and is positioned, with the aid of fluoroscopy, extending through the aorta to a treatment site within an arterial vessel of the heart, or a coronary artery bypass graft.

When the treatment chamber catheter 10 has been positioned, the expandable sealing members 24, 26 are inflated to form a fluid seal with the walls of the blood vessel or bypass graft. The seal thus created prevents the

natural flow of arterial blood through the treatment chamber 34. Perfusion allows the blood to bypass the treatment chamber 34 by passing the blood through the perfusion openings 36, 38 and the interconnecting distally extending first lumen 18. In a preferred embodiment, the effective diameter of the distally extending first lumen 18 and of the perfusion openings 36, 38 allow the blood to flow at a rate of approximately 40 cc per minute.

A device for vascular intervention, for example a catheter-type cutting or grinding instrument (not shown), can now be inserted into the second lumen 20 which opens into the treatment chamber 34. The cutting or grinding tip of the inserted device is moved into the treatment chamber 34. Tissue is accessible to the tip of the inserted device because the treatment chamber 34 is open to the walls of the vessel.

The inserted instrument is operated to loosen the friable material from the walls of the arterial vessel at the treatment site. Excised fragments of the removed material are trapped within the treatment chamber 34. The expandable sealing members 24, 26 prevent the fragments from being carried away by the vessel's natural blood flow.

In a preferred embodiment, the treatment chamber 34 is constantly flushed by infusion through a lumen of the inserted instrument and aspiration through the second lumen 20. Loosened friable material is withdrawn from the treatment chamber 34 as the flushing fluid is withdrawn by aspiration.

Once the friable material has been removed from the vessel walls at the treatment site, the inserted instrument is withdrawn with minimum trauma to the surrounding tissue. Fragments which are too large to be removed in this manner can be reduced in size by using the cutting or grinding instrument before it has been withdrawn. Vacuum is applied via the proximal end of lumen

20 around any inserted instrument.

Once the treatment site has been stabilized by removal of most of the friable material, the treatment chamber catheter can be removed, allowing the use of standard interventions, such as directional coronary atherectomy, angioplasty, and the like. Alternatively, the treatment chamber catheter can be

left in place and another catheter device can be inserted into the treatment chamber for performing a primary intervention.

The Treatment Chamber The treatment chamber 34 is created at the termination of the outer wall

42 (Fig. 2) in the opening 22 of the second lumen 20 and is located between the two expandable sealing members 24 and 26. In a preferred embodiment, the treatment chamber 34 has an effective length of approximately 2 - 4 cm. This effective length is defined as the distance between the two expandable sealing members.

Figures 2 through 6

The multiple lumen catheter member 12 is shown in cross-section in Figs. 2 through 6. Each of these cross-sections is taken in the direction of the arrows at a corresponding line, 2-2 through 6-6, of Fig. 1.

Fig. 2 shows a cross-section taken through the multiple lumen catheter member 12 in the direction of the arrows at line 2-2 of Fig. 1. The multiple lumen catheter member 12 includes the distally extending first lumen 18 and the second lumen 20. The distally extending first lumen 18 has a barrier 46 extending from the proximal end 14 and terminating distally of the distal expandable sealing member 26. The barrier 46 creates an inflation lumen 40 within the distally extending first lumen 18. The distally extending first lumen 18 has an outer wall 44 which separates the lumen 18 from the second lumen 20. The second lumen 20 has an outer wall 42. The guide wire 30 is shown outside the multiple lumen catheter member 12 and adjacent the outer wall 42. The guide wire 30 will typically have a diameter of either 0.014 or 0.018 inch.

In a preferred embodiment, an outer diameter of the multiple lumen catheter member 12 will be approximately 0.105 inch, and an effective working diameter of the second lumen 20 will be approximately 0.080 inch. This working diameter will allow the insertion into the second lumen 20 of a catheter-type instrument having an outer diameter of approximately 0.060 inch.

Methods and apparatus for forming multiple lumen catheters are well known. Typically an extrusion process is used to obtain complex concentric structures such as those used in the present invention. Catheters of very small diameter can be produced by such a process. Fig. 3 is a cross-sectional view taken through the multiple lumen catheter member 12 in the direction of the arrows at line 3-3 of Fig. 1. The proximal expandable sealing member 24 is shown surrounding the multiple lumen catheter member 12. The identification numerals used in Fig. 3 for the details of the multiple lumen catheter member 12 are identical to those shown in Fig. 2. The guide wire 30 is shown inside the distally extending first lumen 18, having passed through an outer wall of the treatment chamber catheter 10, as illustrated in Fig. 1. An opening 48 connects the inflation lumen 40 and the interior of the proximal expandable sealing member 24.

The proximal expandable sealing member 24 can be inflated by an infusion of a liquid at the proximal end 14 into the inflation lumen 40. The liquid will pass along the inflation lumen 40, moving distally, and then urged by the distal termination of the inflation lumen 40 will pass through the opening 48 and into the interior of the proximal expandable sealing member 24. In this manner, the expandable sealing member 24 will become inflated. Fig. 4 is a cross- sectional view taken through the distally extending first lumen 18 in the direction of the arrows at line 4-4 of the treatment chamber catheter 10 of Fig. 1. The identification numerals are the same as those used in Figs. 2 and 3, and refer to the same elements. The guide wire 30 is shown inside the distally extending first lumen 18. Fig. 5 is a cross-sectional view taken through the distal expandable sealing member 26 and the distally extending first lumen 18 in the direction of the arrows at line 5-5 of the treatment chamber catheter 10 of Fig. 1. An opening 50 is shown connecting the inflation lumen 40 with the interior of the interior of the distal expandable sealing member 26. During inflation, fluid being forced into lumen 40 at its proximal end passes through the opening 50 and into the expandable member 26 resulting in

an increase in the diameter of the expandable member. As a result, a biological fluid seal is created between the expandable sealing members 24, 26 and the wall of a biological conduit (not shown). Deflation of both expandable sealing members 24, 26 results when the fluid introduced into lumen 40 is withdrawn. In preferred embodiments, the expandable sealing members 24, 26 are made of either a compliant or of a non-compliant material. The expandable sealing members 24, 26 are attached to the outer surface of the treatment chamber catheter 10 by any of a variety of methods including use of a heat seal, use of adhesive, or by a combination of adhesive and wrapping. An outer diameter of the expandable sealing members 24, 26 varies in a range from 3 mm to about 6 mm and has a typical value of approximately 5 mm.

Reference to Figs. 1 , 3 and 5 shows that the two expandable members 24, 26 do not share a common axis. The proximal expandable sealing member 24 has a common axis with the proximal portion of the multiple lumen catheter member 12. The distal expandable sealing member 26 on the other hand has a common axis with the distally extending first lumen 18. The resulting offset does not prevent formation of an adequate biological fluid seal between the expandable members 24, 26 and the biological conduit. Alternatively, one or both expandable sealing members can be formed to maintain the lumen generally centered within the biological conduit.

Fig. 6 is a cross-sectional view taken through the treatment chamber catheter 10 of Fig. 1 in the direction of the arrows at line 6-6. The distally extending first lumen 18 no longer includes the inflation lumen 40, terminated at the opening 50 to the distal expandable sealing member 26. The guide wire 30 is shown inside the distally extending first lumen 18.

Alternative Embodiments

An alternative embodiment of the treatment chamber catheter 10 of Fig. 1 uses the distal expandable sealing member 26 only. The proximal expandable sealing member 24 is not present. The distal expandable sealing member 26 forms a fluid seal with the walls of the biological conduit and will prevent an

escape, in the distal direction, from the treatment chamber 34 of any excised tissue. But the treatment chamber 34 will not be sealed from the blood flow proximally.

In another alternative embodiment, the treatment chamber catheter 10 of Fig. 1 has no provision for natural perfusion of a biological fluid. Thus the distally extending first lumen 18 does not include openings 36 and 38 for perfusion. The distally extending first lumen 18 serves to support the distal expandable sealing member 26 and the distal atraumatic termination 32 only. Additional alternative embodiments of the present invention will now be described with respect to Figs. 7 through 10. Fig. 7 is a cross-sectional view taken through an alternative embodiment of the treatment chamber catheter 10, and corresponds to a cross-section taken in the direction of the arrows at line 2- 2 of Fig. 1. Fig. 8 corresponds to a cross-section taken in the direction of the arrows at line 3-3 of Fig. 1. Fig. 9 to a cross-section taken in the direction of the arrows at line 4-4 of Fig. 1 , and Fig. 10 corresponds to a cross-section taken in the direction of the arrows at line 5-5 of Fig. 1.

The next alternative embodiment will be discussed with respect to Figs. 7 through 10 and has a provision for independent inflation of the proximal and the distal expandable sealing members 24, 26. Fig. 7 shows that an outer wall 73 of a distally extending first lumen 72 encloses independent inflation lumen 52, 54, one for each of the expandable sealing members 24, 26. In Fig. 8 an opening 56 is shown connecting lumen 52 with the interior of the proximal expandable sealing member 24. Fig. 9 illustrates that lumen 52 terminates distally to the opening 56. Lumen 54 includes no opening to the interior of the proximal sealing member 24, as shown in Fig. 8, and extends distally to an opening 58 into the interior of the distal sealing member 26, as illustrated in Fig. 10. Lumen 54 terminates distally to the opening 58.

In another alternative embodiment, Figs. 7 and 8 illustrate that two additional lumina 60, 62 have been created within the space originally occupied solely by the second lumen 20 of Fig. 2. Lumina 60 and 62 open into the treatment chamber 34, one of the lumina providing for infusion and the other

lumen providing for aspiration of flushing or other fluids and debris within the treatment chamber.

Fig. 11 illustrates an alternative embodiment which includes forced or assisted perfusion in which a mechanical pump is used to maintain or increase a rate of blood flow through the distally extending first lumen 18 and the perfusion openings 36, 38. Fig. 11 shows a portion of the distally extending first lumen 18 of Fig. 1. The distally extending first lumen 18 includes an in-line fluid pumping device 64 which is operated proximally by a rotating control member 66. Rotation of the control member 66 forces a fluid flow within the distally extending first lumen 18 in the direction of the arrows 68 and 70. The rotating control member 66 extends proximally to the proximal end 14 of the multiple lumen catheter member 12. The in-line fluid pumping device 64 has first and second ends and is adapted to mate compatibly with the distally extending first lumen 18. Fig. 12 is a cross-sectional view taken through an alternative embodiment of a multiple lumen catheter member 78 in the direction of the arrows at a point corresponding to the line 2-2 of Fig. 1. The embodiment provides for a forced perfusion, as defined above, and has first and second perfusion lumina, 74 and 76. The first perfusion lumen includes openings 36 (Fig. 1) proximal to the proximal expandable sealing member 24. The second perfusion lumen includes openings 38 (Fig. 1) distal to the distal expandable sealing member 26. Both perfusion lumina 74, 76 are terminated distally of their respective openings 36, 38. A conduit's biological fluid enters the proximal openings 36 and moves proximally through the first perfusion lumen toward the proximal end 14. A perfusion pump (not shown) is connected to the proximal end 14 to receive the fluid moving proximally and to transfer the fluid into the second perfusion lumen. The fluid then moves distally through the second perfusion lumen and reenters the biological conduit through the distal openings 38.

A final alternative embodiment is illustrated in Figs. 13 through 15. The embodiment eliminates the proximal expandable sealing member 24, and replaces the distal expandable sealing member 26 with a filtering member such

as a fine meshed screen member 80.

Fig. 13 is a partial side view showing the treatment chamber 34 and a portion of the multiple lumen catheter member 12 and the distally extending first lumen 18. The screen member 80 has a conical shape, being of greater diameter proximally and being fitted closely to the outer surface 28 of the distally extending first lumen 18 distally of the treatment chamber 34.

An expandable ring member 82 is disposed circumferentially around a proximal end 83 of the screen member 80. A distal end 84 of the screen member 80 is attached to the outer surface 28. The expandable ring 82 is connected via inflation lumen 86 to the distally extending first lumen 18. An alternative embodiment of the screen member 80 includes use of a push wire (not shown) extending distally through the distally extending first lumen 18 and then through an opening, then radially to the proximal end 83 (Fig. 13) of the screen member 80. The push wire encircles the proximal end 83 so that when the wire is advanced distally, it enlarges the proximal end 83 in the manner shown in Figs. 13, 14. When the wire is moved proximally, it causes the screen member 80 to retract to a position shown in Fig. 15. Alternatively, an umbrella type mechanism (not shown) is used to open and close the screen member 80. The distally extending first lumen 18 is terminated distally at an atraumatic lumen termination 32. A guide wire 30 is shown extending distally through the distally extending first lumen 18, and passing through the atraumatic lumen termination 32. The expandable ring 82 is inflated by infusion of a liquid through the distally extending first lumen 18 and the inflation lumen 86.

The alternative embodiment of Fig. 13 is shown in a partial perspective view in Fig. 14. The screen member 80 is shown in an inflated or extended position in which the expandable ring 82 will form a seal with the walls of a biological conduit. When a catheter-type cutting or abrading device is inserted into the treatment chamber 34, excised tissue is prevented from escaping the treatment chamber 34 by the screen member 80 and by the seal formed by the expandable ring 82. The direction of the natural biological fluid flow is indicated by the arrow 88 and is toward the distal end 16 (Fig. 1). The inflation lumen 86

and its connections to both the inflation ring 82 and the distally extending first lumen 18 are more clearly seen in Fig. 14. The inflation ring 82 is seen not to be connected or supported in any manner by the distally extending first lumen 18. Fig. 15 is a partial perspective view of the alternative embodiment of

Figs. 13 and 14, and illustrates the screen member 80 in a deflated or retracted position. The screen member 80 is shown folded closely against the outer surface 28. The expandable ring 82 is shown in a deflated condition against the surface 28. The screen member 80 is placed in the retracted position in order that the treatment chamber catheter 10 can be inserted, manipulated, or removed from a biological conduit.

While the foregoing detailed description has described several embodiments of the treatment chamber catheter device 10 in accordance with this invention, it is to be understood that the above description is illustrative only and not limiting of the disclosed invention. It will be appreciated that the specific arrangement of the lumina relative to one another can differ from the examples shown in the accompanying figures and remain within the scope and spirit of this invention. Thus the invention is to be limited only by the claims as set forth below.