US 3588920 A
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Description (OCR text may contain errors)
June 29, 1971 s. A. WESOLOWSKI 3,588,920
SURGICAL VASCULAR PROSTHESES FORMED OF POLYESTER FIBER PAPER Filed Sept. 5, 1969 INVENTOR Java/v0 A M504 on snr/ BY M L's ATTORNEY United States Patent SURGICAL VASCULAR PROSTHESES FORMED 0F POLYESTER FIBER PAPER Sigmund A. Wesolowski, 44 Roosevelt Ave., East Rockaway, N.Y. 11518 Filed Sept. 5, 1969, Ser. No. 855,585 Int. Cl. A61f 1/24 US. Cl. 3-1 3 Claims ABSTRACT OF THE DISCLOSURE Vascular prostheses characterized by a porosity of from about 550 cc. to 8,000 cc. per minute per square centimeter are constructed of polyester fiber paper having a thickness of from about 64 microns to about 254 microns. The mechanical handling properties are excellent and the residual patency of the implanted prostheses following healing is superior to polyester prostheses having a woven or knit structure.
This invention relates to prostheses constructed to maintain an open lumen when placed in an animal body, particularly in the human body. More particularly, this invention relates to vascular implants for surgical use in the repair and replacement of vessels and tracts in human and animal bodies.
During the past decade considerable attention has been given to the development of artificial vascular parts or grafts as implants for animal bodies. Synthetic fibers such as Vinyon-N, nylon, Orlon, Dacron, Teflon, and Ivalon have been woven and knitted into tubes and other suitable shapes, for use as arteries, veins, ducts, esophagi and the like.
It has been recognized that an artificial graft must meet a number of standards in order to be of value. In particular, the graft must have certain physical properties such that it can be readily handled and manipulated during the specific surgery calling for its use. It must be flexible, for such is essential during an operation when time is critical and the graft must be accommodated to the artery, vein or the like to which it is being secured. It is sometimes necessary in surgery to bend a device or graft either around or under a body organ. An essential feature is that the graft be suificiently rigid, though bendable, to allow for flexing without collapse and closing of the lumen thereof. If the graft does not have such strength, there is ever present the danger that when bent or flexed acutely in the body the lumen would collapse, leading to fatality.
It has also been recognized that a suitable prostheses for the body should be non-toxic, flexible and porous. The ideal prostheses should retain its strength permanently in intimate contact with the body fluids and should be readily accepted and incorporated into the tissues. Porosity is an important characteristic of such a prosthesis to avoid the formation of fluid pockets and to promote the growth through the fabric of repair tissue. Proper merging of the fabric with the body structure is also essential.
It is an object of this invention to provide flexible implants in the form of a tube comprising an association of short polyester fibers of indefinite length that can be handled on conventional paper-making machinery, said fibers ranging from 10 to 15 microns in diameter. The fibers are randomly arranged and bonded together to form a non-woven, paper-like sheet. The structure may be stabilized by fusion of some of the polyester fibers to cause adhesion. Alternatively, various adhesives may be used for this purpose, i.e., a polyamide resin produced by the condensation of a polycarboxylic acid with polyamine (Versamid). If an adhesive is used, it must be applied sparingly to spot-weld the polyester fibers at spaced intervals throughout the area of the paper sheet so as not to decrease unduly the porosity of the fabric. When a polyamide resin is employed as an adhesive, it is heatcured to polymerize and set the adhesive.
A further object of the present invention is to provide a gossamer tube of high porosity. Still another object is to form artificial vascular parts for an animal body suitable for use as a replacement for damaged arteries.
The foregoing objects are realized by providing cylindrical articles of tubular shape comprising a polyester fiber paper. A better description of the vascular prostheses may be had from the following description read in conjunction with the accompanying drawings in which:
FIG. 1 is a perspective view of a Dacron paper tube embodying the invention;
FIG. 2 is a perspective view of the Dacron paper vascular implant of bifurcated form;
FIG. 3 is a cross-section of a vascular prostheses on the line 3--3 of FIG. 1;
FIG. 4 is a longitudinal cross-section on the line 4-4 of FIG. 1; and
FIG. 5 is a cross-section of the tube shown in FIGS. 1 and 4 when in a crimped condition.
The paper that is used to construct the prostheses of the present invention may consist essentially of polyester (polyethylene terephthalate) fibers of indefinite length. The paper is desirably between about 64 microns and 254 microns in thickness. To obtain bonding of the individual fibers throughout the paper sheet, one may include in the polyester fi-ber composition a small amount (1-4%) of a polyester fiber having a melting point that is substantially below the melting point of the polyester fibers that con stitute the major portion of the paper composition. To obtain bonding, the paper sheet, after formation, is heated for a short period of time to the fusion temperature of the low melting polyester fibers, but below the fusion temperature of the higher melting polyester fibers, and then cooled to room temperature.
The vascular prostheses of the present invention may be constructed, as best shown in FIG. 1, by rolling an oblong sheet to form a tube 10 and cementing the longitudinal seam 11 with a suitable adhesive. Adhesives that may be used for this purpose are the Z-cyanoacrylic esters such as methyl Z-cyanoacrylate and isobutyl Z-cyanoacrylate. Alternatively, the longitudinal seams may be secured by sewing with a polyester fiber thread, or by heat sealing.
Bifurcated structures of the type shown in FIG. 2 may be manufactured by making a small longitudinal cut 12 in the wall of a tube and joining thereto one end of a second tube 13 with an appropriate adhesive or by sewing, or heat sealing.
The tubes of the present invention may be crimped to allow for flexing and bending without collapse and closing of the lumen, by placing the uncrimped tube on a glass mandrel of slightly smaller diameter and compressing the tube longitudinally. The glass mandrel with the compressed tube thereon is then heat-set at a temperature slightly below the fusion temperature of the polyester fibers that are present in the paper, and permitted to cool to room temperature. After cooling, a crimped prostheses having the structure illustrated in FIG. may be removed from the mandrel.
Paper polyester fiber tubes constructed in accordance with the present invention exhibit excellent mechanical and physical properties and may be sutured quite like normal aorta. Tests have been performed by implantation into the thoracic aorta of growing pigs for periods of six months. The prostheses demonstrate in general excellent healing properties that compare well with the best healing prostheses of knitted and woven fabrications and show no incidence of obstruction that may sometimes result from the secondary deposition of thrombus upon the inner surface. The general observations with respect to fibrotic and cellular reaction, stenosis, and obstruction is summarized in the following table.
It appears to be an advantage of the polyester fiber paper tubes that the inner capsule is thinner than previously experienced with other prostheses that have been used.
As indicated above, the articles formed as described herein are useful as tubular grafts. They have desired characteristics as revealed by their maneuverability and flexing quality and capability of maintaining an open lumen when flexed. In addition, they have the desired feature of porosity as well as integrating Well with body tissue.
While the invention has been described in detail in accordance with the method of carrying out the process and yielding the products, it will be obvious to those skilled in the art that changes and modifications can be made without departing from the spirit or scope of the invention and it is intended in the appended claims to cover such changes and modifications.
TABLE I.-RELATIVE AOCEPTABILITY OF DACRON PAPER VASCULAR PROSTHESES Average rate in growing pig 1 If corrected for external constriction, residual patency 70.
What is claimed is:
1. A tubular vascular prosthesis formed from randomly arranged polyester fibers bonded together to form a polyester fiber paper implant suitable for implanting in the human or animal body, said prosthesis characterized by having a porosity to water of from about 550 cc. to 8,000 cc. per minute per square centimeter as measured on the Wesolowski scale and having a wall thickness of from about 64 microns to about 254 microns.
2. The vascular prostheses of claim 1 wherein the porosity is 8,000 cc. per minute per square centimeter and the wall thickness is 64 microns.
3. The vascular prostheses of claim 1 in crimped form.
References Cited UNITED STATES PATENTS 3,105,4 2 10/1963 Jeckel 128-334 3,3 16,557 5/1967 Liebig 3-1 3,317,924 5/1967 LeVeen 3l RICHARD A. GAUDET, Primary Examiner R. L. FRINKS, Assistant Examiner U.S. Cl. X.R.