Method And Apparatus For Vein And Artery Reenforcement

Abstract

A novel method and apparatus are provided for applying a textile mesh reenforcing tube on a vein or artery. The mesh tube is gathered on a spool and confined between the end flanges of the spool. After making a severed end of the vein or artery accessible, the spool containing the mesh tube is slipped onto the blood vessel. Then the vessel is anastomosed and blood flow is established through the vessel, expanding the collapsed vessel to normal size. One end of the mesh tube is pulled off one end of the spool and secured on the vessel. By sliding the spool along the vessel, the mesh tube is pulled off the end of the spool and applied progressively to the vessel, the mesh being tensioned sufficiently to contract the tube to fit the vessel. The spool is split longitudinally so that the two halves may be removed from the vessel. The mesh tube subsequently becomes incorporated into the wall of the vessel, making it stronger than a normal artery. Such reenforcement is useful for strengthening an artery in situ and for strengthening a vein graft which is subject to arterial pressure.

Description

BACKGROUND OF THE INVENTION

This invention relates to a method and apparatus for applying a textile mesh reenforcing tube on a vein or artery.

The use of veins from the patient's own body as graft replacements for diseased arteries and to bypass obstructions in certain arteries has a number of important advantages. In the first place, such autogenous grafts do not tend to be rejected by the body as are artificial grafts, heterografts and homografts. Further, there are various veins available in the body which may be removed without producing a serious circulatory deficiency in the patient. It is seldom possible to find an artery of suitable size which may be removed without injury to the patient.

Evidence is accumulating, however, that even autogenous vein grafts degenerate after a few years of exposure to arterial pressure owing to the fact that veins are relatively weaker than arteries. Such degeneration is particularly likely to occur when the vein graft lies free in the abdominal or thoracic cavity. Considering that there is normally a partial vacuum in the thoracic cavity of 2 to 3 centimeters of water, aneurysm formation in vein grafts carrying arterial pressure is more likely to occur in the chest than in any other location in the body. Thus, vein grafts used to bypass obstructions in the coronary arteries are particularly susceptible to aneurysm. In view of the increasing use of vein grafts for such arterial bypass purposes, there is a great need for a convenient and effective vein graft reenforcement. There is also need for reenforcing certain arteries in situ, as for example when an artery wall is weakened by endarterectomy.

Objects of the invention are, therefore, to provide a reenforcement for a blood vessel, to provide an improved vein graft reenforcement, to provide a reenforcing tube of synthetic textile fiber and to provide a convenient method and apparatus for applying a reenforcing mesh tube over a vein or artery.

SUMMARY OF THE INVENTION

According to the present invention, a textile mesh reenforcing tube is pulled over a blood vessel while the vessel is fully expanded under arterial pressure. In order to do this, the mesh tube is gathered on a spool. After one end of the vessel has been made accessible, the spool containing the mesh tube is slipped over the collapsed vessel. Then the vessel is anastomosed and blood flow is established through the vessel.

While holding one end of the mesh tube on the vessel, the spool is moved along the vessel causing the mesh to be stripped from the spool and applied to the vessel under sufficient tension to contract the tube to fit the vessel. The spool is of split construction, allowing its two halves to be removed from the vessel after the mesh tube has been completely removed from the spool. The mesh tube subsequently becomes incorporated into the wall of the vessel, making it stronger than a normal artery.

Mesh tubes are applied in this manner to strengthen vein grafts which are subject to arterial pressure and to strengthen arteries in situ.

The invention will be better understood and additional objects and advantages will become apparent from the following description of the preferred embodiment of the method and apparatus illustrated in the accompanying drawings. Various changes may be made in the details of the method and construction of the apparatus and certain features may be employed without others. All such modifications within the scope of the appended claims are included in the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a heart, with parts broken away, showing a completed coronary bypass embodying the invention and showing the first step in the installation of a second coronary bypass;

FIG. 2 is a fragmentary enlarged view of a portion of FIG. 1;

FIG. 3 is a view showing a subsequent step in the application of the mesh tube to a vein graft;

FIG. 4 is a similar view showing a further step in the method;

FIG. 5 is an enlarged perspective view of the spool shown in FIG. 4;

FIG. 6 is a view showing the final step of the method; and

FIG. 7 is an enlarged side elevation view, with parts broken away, showing the mesh reenforcing tube.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The drawings illustrate the method and apparatus of the invention in connection with a coronary bypass. In FIG. 1 the heart H has coronary arteries 10 and 11 which carry blood from the aorta 12 to nourish the heart muscles. Arteries 10 and 11 lie on the outer surface of the heart where they are readily available after opening the chest. In a common form of heart disease, the upper ends of coronary arteries 10 and 11 become obstructed by deposits 13, shown in FIG. 2, which reduce the flow of blood to the heart muscles thereby rendering the muscles incapable of performing the normal pumping function of the heart and severely limiting the activities of the patient. In FIG. 1, the pulmonary artery 14 has been broken away in order to make the full length of the coronary artery 11 visible.

One way of restoring an adequate blood supply to the heart muscles is to install a bypass 15 around the obstructed portion of each coronary artery. The bypass then carries a normal flow of blood from aorta 12 to a point in the coronary artery below the obstruction 13. When vein graft is used for such a bypass, the danger exists that the vein will not be strong enough to withstand indefinitely the arterial pressure, particularly since the partial vacuum in the chest cavity produces a greater effective pressure on the bypass than in arteries elsewhere in the body.

The method and apparatus of the invention will now be described, by way of example, with reference to a bypass for the coronary artery 11. First, a saphenous or cephalic vein V is obtained from a lower extremity or upper extremity of the patient. These veins are of suitable size for the purpose and may be safely removed without serious detriment to the patient. The tributaries 19 are cut off and ligated, the ends are bevelled at 45.degree. and the normal downstream end of the vein is sutured at 20 to the artery 11 in end-to-side anastomosis. As indicated by the arrow 21, the new arterial flow through the bypass must be in the same direction as the previous venous flow in order to pass freely through the valves in the vein.

A spool S carrying a textile mesh reenforcing tube T is then slipped on the free end of collapsed vein V as shown in FIGS. 1 and 2. Tube T is preferably knitted from a suitable synthetic textile fiber such as Dacron and the ends are bevelled at an angle at 45.degree.. The bevelled ends are pushed back one-eighth inch and fused with a soldering iron to prevent runs in the material and form a strengthened ring to be secured by sutures as indicated at 18 in FIG. 7. The tube is gathered on the spool and confined between a large end flange 22 and a small end flange 23 with the bevelled ends facing away from a tactile indicium knob 24 on the large flange 22. Spool S is preferably made of a suitable plastic which is autoclavable, such as Lexan. It is unimportant which end of the spool goes on the vein first.

Broken-line circle 25 in FIG. 1 indicates the location of an opening to be made in aorta 12 for connection with the upper end of vein V. FIG. 3 shown the upper end-to-side anastomosis completed with sutures 26. With arterial flow established through bypass graft vein V, the lower end of mesh tube T is pulled off spool S over its small flange 23 and secured over the suture line 20 by sutures 30.

Then more of the mesh tube T is pulled off the spool and applied to the vein V by moving the spool upward along the vein. During this movement a portion of tube T is grasped on the vein with one hand while the other hand moves the spool and creates a drag on the gathered portion of the tube remaining on the spool to tension the tube leaving the spool as shown in FIG. 3. The spool and fingers cooperate in this manipulation as in pulling on a stocking. Longitudinal tension on tube T as it is withdrawn from the spool causes the tube to contract circumferentially to fit the vein while the vein is carrying arterial flow. The spool serves as a support tube for the gathering mesh tube and functions as the thumbs inserted in a gathered stocking to tension the stocking as it is drawn out between thumb and fingers.

As the spool is moved along the vein, the indicium knob 24 provides means to avoid rotation of the spool so that the tube T will not be twisted as it is applied to the vein and so that the bevel on the upper end of the tube will be properly oriented to conform to the surface of the aorta 12 as the upper end of the tube is withdrawn from the spool. In the manipulation shown in FIG. 3, the surgeon feels the knob 24 between the thumb and forefinger of his left hand without giving conscious attention to it.

Spool S is split longitudinally in two halves 35 and 36, as shown in FIG. 5. The two halves are normally held together by four pins 37 in part 35 which have a frictional fit in holes 38 in part 36. When mesh tube T has been withdrawn from the spool, the two halves are separated and the spool removed from vein V as shown in FIG. 4. Then the upper end of tube T is secured over the suture line 26 by sutures 40 as shown in FIG. 6. This completes the bypass for artery 11 corresponding to bypass 15 on artery 10. In the course of time the mesh tube T becomes incorporated into the wall of vein V, making the vein even stronger than a normal artery and preventing the development of aneurysms in the graft.

When mesh tube T is stretched on the vein, the length of a given tube varies inversely with the diameter of the distended vein. With a known length and diameter of vein, a tube T is selected which will assume that length, or a little greater length, at that diameter. Any excess length is included in the sutures 40 or distributed back along the vein.

The invention is not limited to a coronary artery bypass nor is it limited to end-to-side anastomoses as described herein. The present method and apparatus are equally well adapted for vein graft replacement of a diseased section of artery involving end-to-end anastomosis. The invention may be utilized to advantage in various parts of the body. It is also useful in reenforcing an artery in situ as, for example, when an artery has been weakened by endarterectomy. In these various applications the mesh tube T may have square cut instead of bevelled ends when desired.

Claims

Having now described my invention and in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

1. The method of applying a textile mesh reenforcing tube to a blood vessel comprising gathering said mesh tube on a supporting tube, inserting an end of said blood vessel through said supporting tube, pulling one end of said mesh tube off one end of said supporting tube and holding said one end of said mesh tube in stationary position on said blood vessel, moving said supporting tube along said blood vessel and causing the rest of said gathered mesh tube to be pulled off said one end of said supporting tube and transferred to said blood vessel, and then removing said supporting tube from the blood vessel.

2. The method of claim 1 including the step of establishing blood flow through said blood vessel before said mesh tube is transferred from said supporting blood vessel.

3. The method of claim 1 including the step of applying a frictional drag to said gathered mesh tube on said supporting tube as said mesh tube is pulled off the supporting tube causing the mesh tube to be tensioned and contracted in diameter as it leaves the supporting tube.

4. The method of claim 1 wherein said supporting tube is removed from said blood vessel by separating two halves of said supporting tube along a longitudinal joint line.

5. The method of claim 1 including the step of anchoring the ends of said mesh tube by sutures.

6. The method of claim 1 wherein said blood vessel is an artery in situ.

7. The method of claim 1 wherein said blood vessel is a vein graft.

8. The method of applying a textile mesh reenforcing tube to a vein graft comprising gathering said mesh tube on a supporting tube, anastomosing one end of said vein, inserting the opposite end of said vein through said supporting tube, anastomosing said opposite end of said vein and establishing blood flow through the vein, pulling one end of said mesh tube off one end of said supporting tube and holding said one end of said mesh tube in stationary position on said vein, moving said supporting tube along said vein and causing the rest of said gathered mesh tube to be pulled off said one end of said supporting tube and transferred to said vein while applying a frictional drag to said gathered mesh tube on said supporting tube to cause said mesh tube to be tensioned and contracted to fit said vein, and then removing said supporting tube from the vein.

9. The method of claim 8 including the step of anchoring the ends of said mesh tube over said anastomoses by sutures.

10. A unit for applying a textile mesh reenforcing tube to a blood vessel comprising a supporting tube having an axial hole adapted to receive said blood vessel, and means holding a textile mesh reenforcing tube gathered on said supporting tube.

11. A unit as defined in claim 10, said means comprising radial flanges on the opposite ends of said support tube confining said gathered mesh tube between said flanges.

12. A unit as defined in claim 10, said support tube being split longitudinally in two halves, and means holding said tow halves together.

13. A unit as defined in claim 10 including a tactile indicium on one side of said support tube.

14. A unit for applying a textile mesh reenforcing tube to a blood vessel comprising a spool split longitudinally in two halves, holes in one of said halves receiving pins in the other half in a frictional fit to hold the two halves together, a large radial flange on one end of said spool, a small radial flange on the other end of said spool, and a protruding indicium on said large flange on one of said halves.

15. A unit defined in claim 14 including a textile mesh reenforcing tube gathered on said spool between said end flanges.