Vessel cutting devices

A catheter-based system for accessing specific body cavities percutaneously and minimizing patient trauma is provided. In the preferred embodiment, in order to create an aperture at an access site in a patient's existing tubular body organ structure, a delivery sheath is passed axially along the interior of a portion of the existing tubular body organ structure to place a distal end of the delivery sheath near the access site. A centering wire is passed axially along the interior of the delivery sheath, piercing through from inside to outside of the patient's existing tubular body organ structure at the access site by causing an end portion of the centering wire to emerge from the distal end of the delivery sheath. A cutting catheter is passed substantially coaxially over the centering wire and axially along the interior of the delivery sheath. The aperture is formed by advancing a distal end of the cutting catheter through from inside to outside of the patient's existing tubular body organ structure at the access site and advancing the distal end of the delivery sheath through from inside to outside of the patient's existing tubular body organ structure at the access site.

BACKGROUND OF THE INVENTION

This invention relates to vessel cutting devices for use in the repair, replacement, or supplement of a medical patient's natural body organ structures or tissues. More particularly, this invention relates to vessel cutting devices for use in vascular anastomosis (the surgical connection of vessels).

An example of the possible uses of the invention is a minimally invasive cardiac bypass procedure. This and other examples are considered in detail in Goldsteen et al. U.S. Pat. No. 5,976,178, which is hereby incorporated by reference herein in its entirety.

Vascular anastomosis is a delicate and time-consuming procedure in which fast and accurate vessel cutting plays a particularly important role.

In view of the foregoing, it would be desirable to provide a catheter-based system for accessing specific body cavities percutaneously, thereby minimizing patient trauma.

It would also be desirable to provide fast and accurate vessel cutting devices.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a catheter-based system for accessing specific body cavities percutaneously, thereby minimizing patient trauma. It is also an object to provide fast and accurate vessel cutting devices.

These and other objects are accomplished by providing a method and apparatus for creating an aperture at an access site in a patient's existing tubular body organ structure by passing a delivery sheath axially along the interior of a portion of the existing tubular body organ structure to place a distal end of the delivery sheath near the access site, passing a centering wire axially along the interior of the delivery sheath, piercing through from inside to outside of the patient's existing tubular body organ structure at the access site by causing an end portion of the centering wire to emerge from the distal end of the delivery sheath, passing a cutting catheter substantially coaxially over the centering wire and axially along the interior of the delivery sheath, forming the aperture by advancing a distal end of the cutting catheter through from inside to outside of the patient's existing tubular body organ structure at the access site and advancing the distal end of the delivery sheath through from inside to outside of the patient's existing tubular body organ structure at the access site.

In one embodiment, the distal end of the cutting catheter is rotated to cut through the patient's existing tubular body organ structure at the access site. In another embodiment, a cutting catheter with a conical (preferably star-shaped) cutting edge is pushed through the patient's existing tubular body organ structure at the access site.

The present invention can also be used to create an aperture in the patient's existing tubular body organ structure by advancing a distal end of the cutting catheter through from outside to inside of the patient's existing tubular body organ structure at the access site.

In the most preferred embodiment, all or substantially all necessary apparatus is inserted into the patient via the patient's existing body organ vessel. In addition, all or substantially all apparatus functions are controlled by the physician (a term used herein to also include supporting technicians) from outside the patient's body.

DETAILED DESCRIPTION OF THE INVENTION

As a preliminary step in creating an aperture at an access site10in a patient's existing tubular body organ structure1, a delivery sheath20is passed axially along the interior of a portion of tubular body organ structure1to place a distal end of delivery sheath20near access site10. When the distal end of delivery sheath20is adjacent to access site10, a centering wire30is passed axially along the interior of the sheath until the end portion of centering wire30emerges from the distal end of the sheath and pokes through from inside to outside of tubular body organ structure1. Centering wire30provides a pilot track for cutting catheter40to follow.FIG. 1ashows the distal end of delivery sheath20in the interior of a portion of tubular body organ structure1with a centering wire30piercing through from inside to outside of the organ structure at access site10.

The distal end of centering wire30is preferably deformable to facilitate deployment and removal, but resumes its operational (preferably hooked) shape once deployed. Centering wire30is kept relatively straight when it is inside sheath20. But, when centering wire30is pushed axially out the distal end of sheath20, it curves to one side, as shown inFIGS. 1a,1band1c.FIGS. 1band1cshow alternative structures for centering wire30. InFIG. 1b, the end portion of centering wire30includes a selectively enlargeable structure (such as a balloon50which extends annularly around the exterior of the centering wire and projects radially outwardly from the centering wire in all radially outward directions when inflated). InFIG. 1c, the end portion of centering wire30includes struts55spaced circumferentially around centering wire30and which are resiliently biased to project from the centering wire after the end portion of the centering wire pierces through body organ structure1at access site10. By providing a selectively enlargeable structure disposed on the exterior of the centering wire at a predetermined distance proximally from the distal end of the centering wire and enlarging that structure after the centering wire has pierced organ structure1, it is possible to prevent the portion of centering wire30which is distal of the enlargeable structure from passing back into the organ structure. In addition to the retaining function, the enlargeable structure serves to seal the aperture and displace tissue from around the outside of organ structure1near access site10, thereby creating a space. Such a space helps to prevent cutting head45from cutting other tissues after exiting organ structure1at access site10.

After piercing through organ structure1at access site10with centering wire30, cutting catheter40is passed substantially coaxially over the centering wire and axially along the interior of sheath20.FIG. 2shows cutting head45of cutting catheter40positioned for cutting at the distal end of delivery sheath20at access site10.

Centering wire30holds cutting catheter40and delivery sheath20against organ structure1at access site10, thereby preventing undue bleeding during and after the creation of the aperture that could occur if the cutting catheter and the delivery sheath were to move away from the access site.FIG. 3shows how the aperture is formed by advancing the distal end of cutting catheter40(i.e., cutting head45) through from inside to outside of organ structure1at access site10by rotating and/or pushing the distal end of the cutting catheter.

As shown inFIGS. 2,3, and4, the distal end of cutting catheter40has a circular cutting edge. Cutting catheter40, which when advanced by rotation, cuts through tissue and removes tissue plug60. The preferred embodiment of cutting head45also includes a serrated cutting edge and an axially aligned recess for accepting tissue plug60. By removing plug60of tissue (rather than merely displacing tissue, as inFIGS. 5 and 6), the elastic recoil of organ structure1at access site10is reduced, which may be a desirable condition for optimal graft attachment.

FIG. 4shows advancing the distal end of delivery sheath20through from inside to outside of organ structure1at access site10and removing centering wire30and cutting catheter40along with tissue plug60contained within cutting head45.

As shown inFIG. 5, non-rotating cutting catheter40can be used to create specific geometric aperture shapes (e.g., oblong aperture70for coronary anastomosis).FIG. 5also shows the use of the present invention in creating an aperture in organ structure1by advancing a distal end of cutting catheter40through from outside to inside of the organ structure at access site10. Centering wire30is tracked through cutting catheter40and is shown piercing organ structure1at access site10. Following such an outside-to-inside aperture, delivery sheath20can be passed axially along the interior of a portion of organ structure1to place a distal end of delivery sheath20near second access site10where an inside-to-outside aperture can be created. (Note that organ structure1is shown smaller in scale relative to sheath20and cutting catheter40.)FIG. 6is a side view of organ structure1, showing aperture70created using non-rotating cutting catheter.40ofFIG. 5.

Cutting catheter40shown inFIG. 7ais a rotating catheter. Cutting head45could be a saw-tooth or a razor-edge type, for example. The distal end of delivery sheath20is shown in the interior of a portion of organ structure1with centering wire30piercing through from inside to outside of the organ structure at access site10, wherein cutting catheter40includes dilator80. Dilator80facilitates advancing sheath20through the aperture (as is shown by the succession of steps illustrated byFIGS. 7band7c).

The outer diameter of dilator80is close to the inner diameter of sheath20and is typically larger than the diameter of cutting head45. As shown inFIG. 7b, as dilator80advances through the aperture at access site10, the aperture is simultaneously sealed against bleeding.

FIG. 8shows delivery sheath20which includes proximal and distal selectively enlargeable structures90,100. Preferably, both selectively enlargeable structures90and100are balloons which extend annularly around the exterior of delivery sheath20and project radially outward when inflated. Although the embodiment shown inFIG. 8includes both proximal and distal selectively enlargeable structures, either one or both may be included. When enlarged, proximal selectively enlargeable structure90prevents more than the portion of delivery sheath20which is distal of the enlargeable structure from passing out of the tubular structure via the aperture. Similarly, when enlarged, distal selectively enlargeable structure100prevents the portion of delivery sheath20which is distal of the enlargeable structure from passing back in to the tubular structure via the aperture.

As an illustrative example of the application of the present invention, consider the following. Delivery sheath20(preferably about 4.0 mm in diameter) including cutting catheter40is introduced into organ structure1percutaneously through the femoral artery near the thigh. Cutting catheter40includes cutting head45(preferably about 3.5 mm in diameter). Delivery sheath20is positioned at access site10, here the ascending aorta. Centering wire30is tracked through cutting catheter40and is caused to pierce the aortic artery at access site10. Cutting catheter40is then tracked over centering wire30by either pushing or rotating (or a combination of both pushing and rotating) and caused to advance through the aortic wall. An approximately 3.5 mm aperture is created with tissue plug60retained in cutting head45and removed along with the cutting catheter40. Delivery sheath20can now be advanced through the approximately 3.5 mm aperture created by the cutting catheter40, causing organ structure1to stretch slightly (i.e., about 0.5 mm). This stretching is desirable because it provides a blood seal around delivery sheath20to prevent bleeding into the chest cavity. Delivery sheath20can now be used to introduce other catheters (including cameras, for example) from the femoral artery into the chest cavity for the purpose of diagnosis or intervention (e.g., grafts or TMR laser surgery).

To minimize patient trauma, delivery sheath20, cutting catheter40, and centering wire30are all preferably coupled to and controlled by a controller located on the outside of the patient.

Various methods and apparatus for delivering and installing plugs in walls of organ structures, as well as methods and apparatus for promoting the closing and healing of apertures in walls of organ structures, are available (e.g., of the type shown in Goldsteen et al. U.S. Pat. No. 5,976,178; published PCT patent application WO 98/47430; and published PCT patent application WO 98/55027, all of which are hereby incorporated by reference herein).

Thus, it is seen that a method and apparatus for creating an aperture at an access site in a patient's existing tubular body organ structure and making it possible to access specific body cavities percutaneously, thereby minimizing patient trauma, is provided. One skilled in the art will appreciate that the present invention can be practiced by other than the described embodiments, which are presented for purposes of illustration and not of limitation, and the present invention is limited only by the claims which follow.