CA2090763C - Method and apparatus for connecting and closing severed blood vessels - Google Patents

Abstract

A device for closing or connecting blood vessels has a plurality of micro miniature barb which pierce the wall of the blood vessel and anchor the device in place.
In one embodiment the fastener is comprised of a male member and a female member which are fastened to blood vessel segments with the micro miniature barbs. The male and female members are joined together by inserting the male member into the female member to form a permanent coupling. The device can also be used for opening a blood vessel which has been narrowed by disease or trauma.

Description

The invention relates to a method and apparatus for connecting or closing severed blood vessels whlch can be used as an alternatlve to suturing.
Many surgical procedures involve partlally or totally severed blood vessels whlch must be connected. The conventlonal method of reconnectlng such vessels and closing inclsions ls by sewing them together with a suitable suture material. Although this procedure has been medically successful, lt can involve considerable time during an operation. Thus, there ls a need for a method and apparatus for quickly connecting or closing severed blood vessels.
Any device which can be used to quickly connect blood vessels together must be compatlble with the human or animal body in which it ls used. Since most blood vessels are flexible, it is desirable that any such device also be flexible.
The present invention provides a closure for blood vessel openings comprised of a ring havlng opposlte faces each face having an outer surface, the ring being sized and adapted to conform to splayed ends of a blood vessel, each face having a plurality of barbs attached to the outer surface of each face, the barbs sized and configured to pierce and anchor ln a blood vessel wall.
Advantages of our mlcro mlnlature blood vessel closure and fastener and method of inserting same wlll become apparent from a descrlption of the present preferred embodiments shown in the drawlngs.

-~ 61874-810 ~ ~.

- 20907~3 BRIEF DESCRIPTION OF THE DRAWINGS
Flgure 1 is a cross-sectional vlew of a portion of a blood vessel containing a device being used to attach blood vessel segments.
Figure 2 is an exploded view of a segment of the device shown in Figure l.
Figure 3 is a side view partially in section of a second embodiment of our device placed wlthin a blood vessel.
Figure 4 is a side view partially in section of the device of Figure 3 placed on the exterior of a blood vessel.
Figure 5 ls a perspective view partially in section of an embodiment of our device in a rolled position.
Figure 6 is a perspectlve vlew partially in section of the device of Figure 5 in an unrolled expanded position.
Figure 7 is a cross-sectional view showing the preferred embodiment of our device.
Figure 8 is an enlarged view of a portion of the embodiment of Flgure 7.
Figure 9 is a plan view of the embodiment shown ln Flgures 7 and 8.
Figure 10 ls a cross-sectional view showing our device used in a blood vessel which has been narrowed by disease or trauma.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Figures 1 and 2 a first embodiment used as a fastener is comprised of a male member 2 and female member 4 which are connected to form of stent. Both the male member and female member are generally cylindrical. They O.
~ ~ t~ 61874-810 - 209076~
should be made of a flexlble material. On the outer surface 5 of the female member and a flrst portlon of the outer surface 6 of the male member we provlde a plurallty of micro barbs 10. The micro barbs are slzed to extend lnto the wall 20 of blood vessel ~A
~ 61874-810 2 ~ fi 3 segments 21 and 22. The segments may have been completely detached or only partly separated from one another by an incision which created gap 24. The micro barbs are generally comprised of a stem 11 and at least one barb 12 which may be of a triangular configurations as shown in Figures 1 and 2. Alternatively, one could use tiny fish hook structures or other shapes which can be firmly embedded into the blood vessel wall. On the inner surface of the female member 4 and on a second portion 9 of the outer surface of the male member 2 we provide mating fastening members which engage to form a permanent connection between the male member and the female member.
In the embodiment of Figure 1 fastening means 16 are generally hemispherical in shape and adapted to receive pods 18 which extend from stems 19 attached to portion 9 of the male member 2. The male member 2 and female member 4 should be made of a flexible biocompatible material.
One suitable material is silicon. Some plastics of the type used for other types of implantable structures may also be appropriate.
In Figures 1 and 2 we have shown a fastening means using a pod on a stem which fits into a hemisphere to form a locked connection. Various other configurations are known in the art which can also be used. For example, one could provide a doughnut shape into which the pods extend rather than the hemisphere 16. Similarly pods 18 20go7~3 could be triangular and inserted into a similarly contoured receiving member.
In Figures 3 and 4 we show a second preferred embodiment of our device 30 which is comprised of a flexible material having a plurality of barbs 10 extending from one surface 32 of the closure 30. The closure could be positioned as a stent within the blood vessel as shown in Figure 3 so that the barb surface engages and anchors the closure to the inner wall of the blood vessel.
lo Alternatively, this closure can be wrapped around the outside of the blood vessel as shown in Figure 4 so that the barbs penetrate and embed within the outer surface 26 of blood vessel segments 21 and 22.
We prefer to make the embodiment of Figures 3 and 4, and both the male member and female member of the embodiment shown in Figures 1 and 2, of a flexible sheet which can be rolled to a diameter smaller than the inside diameter of the blood vessel. The rolled structure is placed at the juncture point of the vessel to be fastened and then expanded to engage the interior wall of the blood vessel.
In Figure 5 we show the female member which has been rolled to a smaller diameter and placed upon balloon portion 40 a balloon catheter 42. It should be noticed that the inner surface of the female member 2 is separated from an overlapping portion of the outer surface 6 of the 20~07~3 female member by a flap 44 extending from a balloon catheter 42. After the female member is located in the proper position the balloon portion 40 is inflated thereby unrolling the female member 2. As shown in Figure 6 after unrolling the device, micro barbs 10 penetrate the blood vessel wall and anchor the female member in place. The male member 2 is inserted in a similar fashion. However, since the interior surface of the male member is smooth it is not necessary to provide a flap to separate adjacent lo surfaces of the male member when it is in a rolled position.
Referring to ~igures 7, 8 and 9 we provide another embodiment comprised of a ring shaped body 36 having a plurality of micro miniature barbs 37 on opposite faces 38 and 39 the ends of the blood vessel segments are splayed. Then the inside wall portion of the vessels are pressed against a barbed face. The barbs penetrate the vessels joining them until tissue regrowth takes place.
Placing the connector on the inside of the vessel avoids 20- the difficulties associated with ring-and-pin type connectors. In this embodiment the splayed ends provide a larger passageway for blood flow than in the embodiments of ~igures 1 and 3. By holding the vessel open, regrowth of the tissue over the stent would be facilitated while the maximum blood flow rate is maintained. To provide flexibility, we may provide score lines 35 on faces 38 and 2 1~ 9 ~ 3 39. The ring could also be made of a radially compressible material. Then the ring 36 could be placed in position and caused to expand thru use of a balloon catheter as in Figure 6 or as a result of the memory of the material.
our device can be used to open vessels that have been narrowed from disease or trauma. In Figure 10 we show a partially occluded blood vessel 50 which has been constricted by deposits 52. Our device 60 is inserted lo with a balloon catheter 42. The balloon portion 40 of the catheter 42 is expanded (see Figure 6) to attach the device to the wall 51 of the vessel 50 at the disease site. Then the balloon portion 42 is deflated and the catheter is removed. Our device remains in place to maintain lumen thru the diseased site.
In all of the embodiments passageways can be provided in the barbs. By fabricating each of the barbs with a passageway 45 and reservoir 46, shown in chain line in Figure 8, the barbed face of the closure could act as a surface of microscopic hypodermic needles. Connection of the passageways to a larger reservoir (not shown) would provide a method of local drug delivery to a specific organ, rather than the bloodstream.
Silicon arrays of these piercing microstructures have been fabricated and having 4 ~m high barbs and tested for gross adhesive capability. One-sided arrays, `- 209~763 approximately lcm2 square, were pressed into sections of a human vena cava obtained from a cadaver. The samples successfully bonded to the tissue, but the tensile strength is, as yet, below that required for clinical application. Electron micrographs of delaminated tissue showed four distinct regions which were characterized by several features. Holes occurred where the barbs penetrated and retracted from the tissue. Some barbs broke where penetration and bonding took place, but the lo silicon pedestal supporting the pointed cap failed.
Intact pieces of silicon bonded to the issue. The silicon substrate itself fractured, probably during insertion.
The epithelial lining separated from the vessel wall, with the mcirostructure arrays remaining bonded to the lining.
From this test it became clear that the barbs need to have a scale comparable to the thickness of the vessel wall for satisfactory bonding. We prefer to have structures on the order of S0 to 100 ~m high, or greater.
Although our structures were made using a photolithographic process other techniques could be used.
For example, micromachining, crystal growing methods, vapor deposition, particle beam manufacturing and other techniques for creating microstructures are possibilities.
Although we have described and shown certain present preferred embodiments of our closure and fastener `~ 2Q~0763 and method of inserting same, it should be distinctly understood that our invention is not limited thereto but may be variously embodied within the scope of the following claims.

Claims (3)

1. A closure for blood vessel openings comprised of a ring having opposite faces each face having an outer surface, the ring being sized and adapted to conform to splayed ends of a blood vessel, each face having a plurality of barbs attached to the outer surface of each face, the barbs sized and configured to pierce and anchor in a blood vessel wall.

2. The closure of claim 1 wherein the barbs extend 50 µm to 100 µm from each outer surface.

3. The micro fastener of claim 1 or claim 2 wherein the barbs contain a passageway through which a fluid may flow from a reservoir.