Patent Application: US-93333992-A

Abstract:
adjustable , flexible suture 2ings , mitral and tricuspid annuloplasty 2ings having internal drawstrings that emerge from the 2ings on the annular faces so that the drawstring knots are out of the bloodstream , the drawstrings being contained in clearly marked channels , the mitral 2ing having a curved semi - flexible stiffener member in the anteri / r segment to maintain intertrigonal distance during implantati / n are disclosed .

Description:
the following description of the preferred embodiments of the invention are exemplary , rather than limiting , and many variations and adaptations are within the scope of the invention . in one facet , the invention is directed to adjustable and flexible atrioventricular annuloplasty rings containing circumferential radiopaque markers with one preferred embodiment for use in mitral valve and a second preferred embodiment for use in tricuspid valve repair . adjustment of the ring diameter is achieved by means of internal drawstrings . to avoid the presence of a bulky knot on the inflow aspect of the rings , the drawstring exit points are preferably located on the face of the ring which lies adjacent to the tissue annulus . hence , when the drawstrings are tightened and pairing ends are tied together , the knots are formed between the annulus and the ring , out of the direct blood flow . in the preferred embodiment of the invention intended for use in the mitral valve , the flexible , contractile portion of the prosthesis is formed to fit about the base of the posterior leaflet of the valve . a plurality of pairs of drawstrings are located in the posterior segment of the ring to allow adjustment of segments of the posterior portion of the mitral valve annulus . a curved framework member located in the anterior portion of the prosthesis is to maintain the natural geometry of the anterior segment during implantation . it is shaped to follow a curved path on an inclined plane on the sub aortic curtain above the so called annulus of the anterior leaflet . colored trigone markers in the anterior segment are used as sizing and implanting guides . when the mitral annuloplasty ring is secured into position about the valve , any or all of the drawstrings located in the posterior segment of the valve annulus may be tightened if required to halt or minimize any residual valvular insufficiency . drawstring tightening may be made individually or together in pairs to minimize any remaining insufficiency . this fine tuning capability allows a larger , rather than a smaller ring to be implanted and then the size optimally reduced . in the preferred embodiment of the invention intended for use in the tricuspid valve , the prosthesis is flexible around its circumference and is formed to fit about the base of the valve leaflets . a contractible portion of the prosthesis is formed to fit about a substantial portion of the base of the posterior segment , and may extend into a insubstantial portion of the base of the anterior segment of the valve annulus . this contractible segment incorporates a pair of drawstrings to allow adjustment of a substantial segment of posterior annulus and an insubstantial segment of the anterior annulus at implantation . when the tricuspid variant is secured into position about the valve , the drawstrings located in the posterior segment of the valve annulus may be tightened if required . tightening may be individually or in pairs to minimize any remaining insufficiency . this fine tuning capability allows a larger , rather than a smaller ring to be implanted and then the size optimally reduced . the flexible contractible body of the ring common to both variants is of a biocompatible cloth , preferably of a braided polyethertetraphylate tubular material . during construction of the ring , the tubular braid is cut to length and invaginated to form a double walled tube having a roll over fold at one end , and the two cut ends at the other . the two walls of the tube are heat sealed ( welded ) together close to the two cut ends and at an appropriate distance from the folded end using a heated knife . this heat seal forms a circumferential weld around the tube . the tube is then rolled so that the weld line will lie substantially centrally in the inner wall of the tube . the tube is then heat set into a &# 34 ; v &# 34 ; configuration . this configuration produces an eight walled flexible contractile member when the annuloplasty ring is completed . two of the many steps in the completion of the ring include the sewing of the folded ends together to form a radial seam , and sewing of the pieces of the &# 34 ; v &# 34 ; together to form a circumferential seam . various components , such as drawstrings , stiffener and radiopaque markers are conveniently placed within and / or sewn in the &# 34 ; v &# 34 ; form before the circumferential seam is completed . this construction method produces an annuloplasty ring that is relatively simple to manufacture , yet contains drawstrings to provide adjustability , radiopaque markers for postoperative assessment , and a semi - flexible member in the anterior portion of the mitral variant to maintain the natural geometry of the intratrigonal and anterior leaflet distance . at the same time it provides adequate strength and flexibility , yet permits a low needle penetration force for convenience of implantation . a particular advantage of this construction is that there are no portions of the textile material that might fray , and that the weld line is so placed within the ring is both inconspicuous and not subject to undue stresses . the body is substantially oval in cross - section . referring to the drawings wherein like numerals indicate like elements there is shown in fig1 and fig2 plan views ( from the annulus and atrium aspects respectively ) of the preferred embodiment of a flexible , adjustable annuloplasty ring intended for the mitral valve designated as 10 . fig3 shows a side view and fig4 shows an end view of the preferred embodiment of the variant of the ring intended for the mitral valve . fig5 shows a cross - sectional view taken along line 5 -- 5 of fig2 . fig6 shows a cross - sectional view taken along line 6 -- 6 of fig2 . the device is composed of a tubular body of textile nature 11 , which has its folded ends sewn together at seam 12 to form a ring . the ring has three segments , the anterior segment 13 , the right posterior segment 14 , and the left posterior segment 15 . in the interior of tubular body 11 are provided filiform strings 20 , 21 , which have external portions 22 , 23 , 24 , 25 . these strings , which are preferably of a braided polyester surgical suture , emerge from the annulus face of the ring at exit points 26 , 27 , 28 , 29 respectively . the distance between exit points 26 and 28 are approximately 3 mm . the distance between exit points 27 and 29 is similar . the strings are anchored to the ring at points 30 , 31 , and 32 . points 33 and 34 are colored markers sewn onto the upper ( atrial ) surface of the ring that are intended as guides for implantation . these points are intended to lie adjacent to the right and left fibrous trigones of the mitral annulus . also at implantation , point 31 will approximately correspond to the junction of the anterior leaflet and the right commissural leaflet of the mitral annulus . point 32 will approximately correspond to the junction of the anterior leaflet and the left commissural leaflet . an internal curved flexible stiffener member 35 spans the area corresponding to the anterior segment of the mitral annulus from points 31 to 32 , and has a closed loops 36 , 37 at its ends . drawstring 20 is passed through these loops and through the walls of body 11 to form part of the anchor knots at 31 and 32 . drawstring 21 is passed through the walls of body 11 to lie externally for a short distance 30 and is tied internally to form the anchor knot laying under external portion 30 . the framework or stiffener member 35 is preferably of a biocompatible corrosion resistant metal wire with good flexure fatigue resistance such as carpenter mp35n ® alloy or elgiloy ®. reference is made briefly to fig1 through 14 . a wire 35 of the material described , e . g . carpenter mp35n , 0 . 028 &# 34 ; diameter , or equivalent , is first inspected . next , the wire is cut to the desired length , with an abrasive saw , or an equivalent device , burnished to assure that it is smooth , and secured in a jig such as is depicted in fig1 . the jig comprises a base plate 310 , a locking bar 311 and a wedge plate 312 having an incline surface 314 are secured to the base plate . a lock plate 315 is secured to the base plate 310 lock bar 316 , has a beveled corner 317 to receive the wire 35 . lock bar 316 interacts with lock bats 311 - 315 and locks firmly in position the wire 35 . the wire 35 extends to the edge of the base plate which serves as measure of the length of wire to be formed into a loop and lies adjacent a mandrel post 318 that is less than the diameter of the loop to be formed in the end of wire 35 . a bending tool 319 , comprising a knob capable of being gripped and turned , with a downwardly extending portion 320 having formed centrally therein an aperture 321 sized to slip snugly over mandrel post 318 and an engaging post 322 that is spaced from the aperture a distance slightly larger than the diameter of the wire 35 . the bending tool is fitted over the mandrel post , the wire 35 being received between the mandrel post and the engaging post . the bending tool is turned thereby bending the wire 35 into a semihelical loop . it is necessary to bend the wire into a smaller loop than the ultimately desired loop because the wire rebounds slightly from its ultimately looped configuration . when the bending tool is removed , the wire , which has been burnished to assure that it is smooth , assumes the configuration shown in fig1 a and 12b , with the loop , such as loop 36a or 37a , spiraling partially out of the plane of the wire . the end of the wire , e . g . 36b or 37b , which has been smoother cut with an abrasive saw and rounded and burnished to remove all sharp edges , burrs , etc ., is then bent downwardly so that the loops lie in the same plane as the wire , as shown in fig1 c and 12d , the ends lying closely adjacent the wire a short distance from the ends . the loop is bent to assure that the end of the wire , as bent , depicted in fig1 a and 12b , does not overlap the portion of the wire to which is closely adjacent . when the loop is bent into the plane of the wire , the wire in that portion is not dented , distorted or deformed . as a final step , before final inspection , the stiffener 35 is burnished again to assure that it is perfectly smooth , free of indentations or deformations that may weaken it , and free of sharp edges or other structures that might abrade the fabric of the ring . a colored demarcation suture line 38 on the upper ( atrial ) surface of the ring body indicates to the surgeon a line , outside of which the implanting sutures must be placed to avoid interference with the internal drawstrings or the stiffener member . a corresponding , but preferably uncolored , demarcation suture line 39 is situated on the lower ( annulus ) surface of the ring body . a flexible radiopaque member 40 , is contained within body 11 , in the posterior region between drawstring anchor points 31 and 32 . this member , in conjunction with metallic stiffener 35 , forms a circumferential x - ray marker . member 40 may conveniently be composed of a single continuous length of 0 . 020 &# 34 ; diameter extruded silicone rubber impregnated with 55 % barium sulfate and 6 % tungsten . material of this composition and diameter is sufficiently radiopaque , but does not unduly impede the passage of the needles of the implanting sutures . it has elements 41 , 42 , &# 34 ; hairpin &# 34 ; bends 43 , 44 , and ends 45 , 46 . the &# 34 ; hairpin &# 34 ; bends 43 44 , lie adjacent to loops 36 , 37 respectively , and ends 45 , 46 lie adjacent to seam 12 . fig5 shows a cross - sectional view taken along line 5 -- 5 of fig2 . cloth layers 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 are formed from a singular tubular braided length of material folded and joined as previously described . the four cloth layers , when folded and heat set form an upper ( atrial ) surface 100 , and a lower surface 107 that will lie on the natural annulus . colored demarcation stitch 38 passes from cloth layer 100 , through layers 101 , 102 , 103 and hence back to layer 100 . the second demarcation stitch 39 , which is preferably uncolored ( white ), is similarly passed from cloth layer 107 , through layers 106 , 105 , 104 and hence back to layer 107 . demarcation sutures 38 , 39 passing through their respective cloth layers delineate channel 108 which contains drawstring 20 ( or 21 ). radiopaque marker member portions 41 , 42 are enclosed between cloth layers 103 , 104 . a helical , continuous , circumferential sewn seam 109 joins cloth layers 100 , 101 , 102 , 103 to corresponding cloth layers 107 , 106 , 105 , 104 . fig6 shows a cross - sectional view taken along line 6 -- 6 of fig2 . framework member 35 is retained along its length against the fold 110a of the cloth layer 103 , 104 by a continuous helical thread 111 , and / or by suture ties 38 and 39 , for example . the fold 110a is a single layer of tubing lying innermost in the four - layer braided fabric construction , the exterior bend 110b forming the outermost layer of said four - layer construction fig7 and fig8 show plan views ( from the annulus and atrial aspects respectively ) of the preferred embodiment of a flexible , adjustable annuloplasty ring intended for the tricuspid valve designated as 200 . fig9 shows a cross - sectional view taken along line 9 -- 9 of fig8 . the device is composed of a tubular body of textile nature 201 , which has its folded ends sewn together at seam 202 to form a ring . in the interior of tubular body 201 is provided a filiform string 203 which has external portions 204 , 205 . this string , which is preferably of a braided polyester surgical suture , emerges from the annulus face of the ring at exit points 206 , 207 . the distance between exit points 206 and 207 is approximately 3 mm . the string also emerges from , passes around the body ( 208 , 209 ) and reenters the body 201 at the drawstring anchor points . the string is anchored in the ring by internal looped knots adjacent to external loops 208 , 209 . a colored marker 210 is sewn onto the upper ( atrial ) surface of the ring . this is a guide to the surgeon , indicating the point that should be positioned adjacent to the junction of the septal and anterior leaflet at implantation . a colored demarcation suture line 211 on the upper ( atrial ) surface of the ring body indicates to the surgeon a line , outside of which the implanting sutures must be placed to avoid interference with the adjustable segments of the internal drawstring 203 . a corresponding , but preferably uncolored , demarcation suture line 212 is situated on the lower ( annulus ) surface of the ring . a flexible member 213 , is contained within body 201 . this member forms a circumferential radiopaque marker . it may conveniently be composed of a single length of 0 . 020 &# 34 ; diameter extruded silicone rubber impregnated with 55 % barium sulfate and 6 % tungsten . this member 213 , having ends 214 , 215 lying adjacent to seam 202 passes twice around the circumference of the ring to form concentric members 216 , 217 . fig9 shows a cross - sectional view taken along line 9 -- 9 of fig8 . cloth layers 300 , 301 , 302 , 303 , 304 , 305 , 306 , 307 are formed from a singular tubular braided length of material folded and joined as previously described . the four layers , when folded and heat set , form an upper ( atrial ) surfaces 300 , a lower surface 307 that will lie on the natural annulus . colored demarcation stitch 211 passes from cloth layer 300 , through layers 301 , 302 , 303 and hence back to layer 300 . a second demarcation stitch 212 , which is preferably white , is likewise passed between cloth layer 307 , through layers 306 , 305 , 304 and hence back to layer 308 . demarcation sutures 211 , 212 passing through their respective cloth layers delineate channel 308 which contains drawstring 203 . radiopaque marker member elements 216 , 217 are enclosed between cloth layers 303 , 304 . a helical , continuous , circumferential sewn seam 309 retains cloth layers 300 , 301 , 306 , 307 together . in the embodiment of the annuloplasty ring specifically adapted for use in repairing a human mitral heart valve having an anterior segment and a right and left posterior segments a braided fabric tube is connected to form the tube generally into an annulus . the stiffener wire extending substantially the length of the anterior segment , the stiffener wire having first and second ends , said ends being configured to form loops on the respective ends thereof . as depicted in fig1 , a first string 20 extends from channel 108 upwardly through the wall 110a of the tube at a first point 20a a first distance from the first end of the wire into the tube . adjacent the first end of the wire the string extends outwardly through the tube four - layer wall at 20b thence around the tube as indicated at 20c , thence inwardly through the four layers proximate the first end of the wire , 20d , thence through the loop 37 in said first end of the wire 35 , thence outwardly through the walls , 20e , thence around the first string outside the tube , 20f , thence inwardly through the walls , 20a , and over the first string at again , 20h forming a knot to secure the string 20 and the first end loop 37 of the wire 35 to the tube proximate the first end of the wire . the string 20 then extends through the wall 110a at 20i , and along the length of the tube . at the second end of the tube , knot is repeated from the direction of the wire , i . e . a mirror - image of the arrangement just described is formed securing the other end of the wire and the string to the tube proximate the second end of the tube . as will be apparent , the securement just described can be accomplished from either direction , relative to the end of the wire , and may be the same or reversed , e . g . a mirror image knot , at the respective ends of the wire . other knot securements may also be used . from the second end the string extends along the inside of the tube a second distance and thence outwardly through the tube wall at a second point said second distance from the second end of the wire , a first end of the first string extending out of the tube wall proximate the first point , the second end of the first string extending out of the wall proximate the second point 20b . the points 20b , 20e , and 20g may be coincident , i . e . a single hole may define all of these points . one or more strings may be provided extending from outside the annulus proximate said first point , through the tube away from the first end of the wire toward the second point , outwardly through the tube wall and inwardly through the tube wall proximate a third point , that may , if desired , be approximately equidistant from the first and second ends of the wire , to secure the second string proximate said third point , along the inside of the tube to proximate the second point , and thence through the tube wall , a first end of the second string extending out of the tube wall proximate the first point , the second end of the second string extending out of the tube wall proximate the second point ; the first ends of the respective strings comprising a first pair of drawstrings for permitting contraction of the annulus between the first end of the wire and the first point and between the first point and the third point , respectively ; the second ends of the respective strings comprising a second pair of drawstrings for permitting contraction of the annulus between the second end of the wire and the second point and between the second point and the third point , respectively . the wire is preferably polished on all surfaces , the ends thereof are radius ed and wherein the loops are formed without denting the wire in the portions thereof that lie adjacent the ends of the wire . fig1 shows an isometric view of the preferred embodiment of the ring for mitral valve repair sewn onto the mitral annulus of the heart ( the left atrium is removed for clarity of illustration ). the heart is shown during ventricular systole ( i . e . the mitral valve is closed and the left ventricular outflow tract is pressurized ). the annuloplasty ring 10 , is positioned such that colored markers 33 , 34 , are coincident to the right fibrous trig one 401 and left fibrous trig one 402 of the mitral valve apparatus . the anterior leaflet 403 is shown coapting to the posterior leaflet 404 . seam 12 will lie approximately at the midpoint posterior portion of the annulus . drawstring anchor point 31 is located on the annul us approximately at the junction of the anterior leaflet and the right commissural leaflet , 405 . likewise , drawstring anchor point 32 is located on the annul us approximately at the junction of the anterior leaflet and the left commissural leaflet , 406 . the curved anterior portion of the ring 13 containing the internal curved framework member spans the anterior segment of the mitral annulus 403 from points 31 to 32 . as manufactured , the plane of segment 13 lies in the same plane as the ring , as shown in solid lines in fig3 and as depicted in fig4 a . the flexible ring forms a hinge immediately adjacent the ends of the framework member permitting the framework member to hinge or bend outside the plane of the ring up to an angle of approximately 85 ° relative to the plane of the remainder of the ring . depending on the particular application of the ring , the framework may , during some periods of time , hinge such that the plane in which the framework lies is at an angle typically of about 45 ° and up to 85 ° relative to the plane of the remainder of the ring . in some applications , the ring , including the framework portion , will lie substantially in the same plane . the angle , if any , in which the framework lies is not a function of the annuloplasty ring per se but rather of configuration of the heart , or other organ , to which the ring is applied and to the method the surgeon uses for applying the ring . a colored demarcation suture line 38 on the upper ( atrial ) surface of the ring body indicates to the surgeon a line , outside which the implanting sutures 407 must be placed to avoid interference with the internal drawstrings or the stiffener member . numerous interrupted sutures 407 , are used to fix annuloplasty ring to the mitral valve annulus and to the sub aortic curtain 408 . external portions of the drawstrings 22 , 23 , 24 , 25 may be tightened and tied to the adjoining drawstring to constrict the ring where required to correct or minimize valvular insufficiency . the act of drawing in either or both drawstrings 22 , 24 and or 23 , 25 will cause the ring to contract between the drawstring anchor points 30 and 31 or 30 and 32 respectively . the amount of contraction will depend upon how much each drawstring is tightened , and whether only one or all drawstrings are tightened . by such means the circumference of the annulus may be further reduced to correct or minimize any remaining valvular insufficiency following ring implantation . it is emphasized that , as to the present invention , there is no significance to the showing or one or two or three pairs of drawstrings , as any number of drawstrings are contemplated by this invention . fig1 shows a plan view of the preferred embodiment of the invention for tricuspid valve repair sutured in place in the typically enlarged tricuspid annulus ( as described by bex j . p . and lecompte y . &# 34 ; tricuspid valve repair using a flexible linear reducer &# 34 ;, j cardiac surg , 1 : 151 , 1986 ). the tricuspid valve has an anterior leaflet 501 , a posterior leaflet 502 and the septal leaflet 503 . the junction of the septal and anterior leaflets is 504 , the junction of the anterior and posterior leaflets is 505 , and the junction of the posterior and septal leaflets is marked 506 . the dotted line 507 shows the circumference of the annulus before pathologic dilatation . the annuloplasty ring 200 , is positioned such that colored marked 210 is approximately coincident with junction 504 . numerous interrupted sutures 508 , are used to fix annuloplasty ring to the tricuspid valve annulus . the adjustable segment is delineated from drawstrings anchor points 208 to 209 . typically , this adjustable segment will approximately straddle a substantial portion of the posterior leaflet 502 , as well as the junction of the posterior and anterior leaflets 505 . it may also straddle an insubstantial portion of the anterior leaflet 501 . the act of drawing in either or both drawstrings 204 , 205 will cause the ring to contract between the drawstring anchor points 208 and 209 . the amount of contraction will depend upon how much the drawstring is tightened , and whether only one or both drawstrings are tightened . by such means the enlarged circumference of the annulus may be reduced to that shown by dotted line 507 . following appropriate reduction the drawstring pairs are tied using a surgeon &# 39 ; s knot which will lie between the ring and the annulus , out of the bloodstream . referring now to fig1 a - 16e , the initial steps in manufacturing the braided ring is described . a pre - washed length of heat - setable , meltable braided fiber tubing 350 , e . g . atkins & amp ; pearce braided polyester tape , is cut to the desired length , e . g . 250 - 290 mm , and the cut length is slid over a mandrel , rolled back onto a pusher rod 352 so as to form a double walled tube , having an inner wall 356 and an outer wall 354 , approximately half the length of the original tubing . the tube has an inward fold 358 from outer wall 354 to inner wall 356 forming one end , the right end as depicted in fig1 a , the other ends of the tubing 360 and 362 lying generally adjacent each other . referring to fig1 b , the double walled tube 370 is cut to a desired length , e . g . 112 - 133 mm , at 364 with a heated blade that cuts by melting the fibers and fusing the fibers together to form a fused end , the inner and outer walls being joined in an annular fused joint at 364 . referring to fig1 c , temporary sutures 366 and 368 are secured only through the outer layer 354 a desired distance , e . g ., 56 - 66 mm from the end of the tube . the fused joint 364 is then rolled into the inside of the tube so as to turn a portion of the tube inside out , the temporary sutures being used to pull the layer through which they extend to roll the tube inside out to position the fused joint in the inside wall , preferably in the center of the inside wall of the tube 370 . to clarify , the tube as shown in fig1 b , is rolled inside out so that the sealed - cut ends are on the right as shown in fig1 c , the sutures are attached , and the tube is further rolled partially inside out until the sutures are at the right end as shown in fig1 d with the heat - sealed joint between the original ends of the tubing inside the final two - lay tube as shown in fig1 . the steps in forming the final tube are depicted in fig1 a - 17b and depict the steps of one facet of the invention , namely the method of manufacturing an annuloplasty or suture ring comprising the steps of invaginating tubing 350 braided of meltable , heat setable polymer fibers to form a tube 370 of an outer layer and an inner layer of tubing , a first end of the tube thus formed being defined by an annular , inward fold 358 of the tubing from the outer layer to the inner layer ; forming a second end 364 of the tube by melting the inner and outer layers of tubing to fuse said layers together in an annular seal between said layers ; and sliding said layers relative to each other defined new ends of annular , inward folds of tubing and to space the annular seal 364 distal from and between the newly formed ends inside the outer layer of the tube . this double wall tube may be used in the devices of this invention , as a suture ring for heart valves and in any other device or method wherein a fabric suture strip , ribbon or ring is used to secure a prosthesis to tissue or to secure tissue to tissue . referring to fig1 and 19 , the method , as used in making the aforementioned suture or annuloplasty rings , further comprises heat setting the thus formed tube 370 into a lateral v - shaped band 380 having a center heat set crease comprising four layers of tubing . reference is made specifically to fig1 which depicts , in exploded view , the fixture for heat setting the tubing 370 into a v - shaped band 380 . the double walled tube 370 is slipped over a v - shaped mandrel 372 which may be of metal or high temperature resistant polymer , e . g . polytetrafluoroethylene . the mandrel 370 carrying on it the tube 372 is clamped between forming tools 374 and 376 which define a v - shaped opening the size and shape of the desired v - shaped band . a pair of bolts , c - clamps , or any other clamping device may be used to secure the forming tools together . bolt are preferred to maintain alignment of the tools . the clamped tools with the mandrel and tube are placed in an oven , or otherwise heated , to a temperature sufficient to heat set the polymer of which the tubing is formed without fusing it . in the case of polyester , temperatures in the range of 100 °- 110 ° c . are quite suitable in most instances . after a sufficient period , usually about ten minutes , to heat form the tubing , the clamped mandrel , with the tube in place , is first cooled to set the tube into a v - shaped band or tape 380 and then removed . the v - shaped band may be secured end - to - end to define a suture ring , such as , for example , the suture ring 382 depicted fig2 - 22 . the suture ring 382 is formed of a length of v - shaped band or ribbon 380 secured end - to - end in any desired manner . such a ring may be used for heart valve prostheses , for example . if desired , a drawstring 384 may extend through the tube , and through the tube walls , around the inner periphery of the suture ring . pairs of demarcation seams 386 and 388 are sewn around the ring to maintain the drawstring in place and stabilize the ring . these demarcation seams may be of different colors thereby identifying the respective sides of the ring . the ring is closed at a first outer periphery by closure suture 390 . in use , the drawstring may be a heat - shrink type monofilament or polyfilament string . the ring is placed on the prosthesis , the drawstring 384 tightened and tied . the prosthesis may then be heated causing the drawstring to form an extraordinarily tight and strong securement of the ring to the prosthesis . the use of a heat shrink drawstring is not necessary , of course . in some applications , where x - ray identification or location of the suture ring is desirable , a radiopaque fiber 392 wrapped two or more times around the ring or placed such that two or more fibers lie adjacent each other . the invention , as described , may be in the form of a suture ring for use in surgery for securing a prosthesis in or adjacent to an annular organ structure or stabilizing or shaping a generally annular organ portion . the suture ring comprises an elongate braided biocompatible ribbon 380 having ends , elongate edges and a central portion , the lateral cross - section of the ribbon generally defining a v - shape , the edges extending outwardly from the center , means securing the respective ends of the ribbon together thereby configuring the ribbon generally into an annulus , the central portion defining the internal periphery of the annulus , the edges extending outwardly from said internal periphery . the ring may be provided with at least one drawstring 384 extending around at least a portion of the annulus and through the ribbon selectively to decrease the diameter of the internal periphery of the annulus , the drawstring being disposed adjacent said center , the edges extending outwardly from the drawstring . the drawstring may be omitted and the ring secured to a valve using one or more wraps of heat - shrinkable material , e . g . polyester , to tie the ring to the valve . means are provided for securing the edges of the ribbon together , the edges of the ribbon defining the external annulus periphery . the drawstring and ribbon - like like member are so constructed and configured that when the draw - string is drawn the internal diameter of the annulus contracts and the width of the annulus increases thereby substantially preventing the ribbon - like member from gathering into irregular clumps as the internal diameter of the annulus contracts . the ability of the ring to contract in its interior annulus without bunching , gathering or folding is a great advantage . the construction described permits the excess material to expand laterally outwardly as necessary without bunching . the method of use of is as follows . the left atrium is exposed following a mid - line sternotomy , and cardio - pulmonary bypass established using conventional techniques . a left ventricular drain may be inserted into the apex of the left ventricle . the aorta is cross - clamped and a cold cardioplegia solution is pumped into the aortic root causing the heart to be cooled and inducing cardiac arrest . alternatively , retrograde cardioplegia may be given via the coronary sinus . an incision is made into the left atrium , exposing the damaged mitral valve . the technique so far described is a general description of mitral valve exposure , and is not specific to the particular device . surgical techniques of implantation vary between centers . the surgeon will then carefully examine the mitral valve mechanism to ascertain if the valve is amenable to repair , and if so , what the mechanism of repair will be . for example , the lesion may be at the level of the annulus , leaflets , chordae , or papillary muscles . the appropriate surgical repair procedure will depend upon the pathology found . in cases where the annulus is enlarged , or where a segment has been removed from the mitral valve leaflets , the mitral valve annuloplasty ring will be implanted as part of the repair procedure . first the appropriate size ring is chosen using the sizer set supplied for this purpose . interrupted sutures are placed at the fibrous trigones , between the trigones , and around the remaining circumference of the annulus . the sutures are passed through corresponding portions of the annuloplasty ring , outside the line of demarcation , marked by the colored suture line on the atrial side of the annuloplasty ring . the ring is then pushed down the sutures until it lies on the annulus . each interrupted suture is tied and cut . mitral valve competency is then assessed by suitable means ( e . g . by the injection of a saline solution through the left ventricular drain , or by removing the aortic cross - clamp and temporarily rendering the aortic valve incompetent ). if the mitral valve is regurgitant the areas of reflux are noted . if leakage occurs in the right posterior leaflet , this area of the ring is contracted by gently pulling on one or both of the drawstrings in this region of the ring . it may be necessary to tighten one or both drawstrings pairs depending upon the individual valve pathology . mitral valve competence is again assessed , and if necessary further adjustments made . when the surgeon is satisfied that an optimum mitral valve competence has been achieved without compromising mitral valve opening area the drawstrings are tied as pairs . the surplus portions of the drawstrings are cut close to the knots . mitral valve competence is then confirmed . at this stage , should any slight reflux be present , it can be eliminated or minimized by placing one or more plicating sutures at the appropriate portion of the annuloplasty ring . however , should a drawstring have been inadvertently over - tightened , it may be cut below the knot to release the constricting segment . that portion of the ring might then need to be shortened by the placement of sufficient plicating sutures . the left atrium is then closed , air removed from the heart , warm blood allowed to reperfuse the coronary tree , the heart defibrillated if necessary , and the patient slowly weaned from cardiopulmonary bypass . implantation of the tricuspid ring follows a similar course with variations appropriate to the different anatomy and the corresponding differences in the tricuspid and mitral annuloplasty rings . ______________________________________references citedunited states patents______________________________________3 , 491 , 376 01 / 1970 shiley3 , 534 , 411 10 / 1970 shiley3 , 656 , 185 4 / 1972 carpentier4 , 042 , 979 8 / 1977 angell4 , 055 , 861 11 / 1977 carpentier et al . 4 , 164 , 046 8 / 1979 cooley4 , 217 , 665 8 / 1980 bex et al . 4 , 263 , 680 04 / 1981 muller , et al . 4 , 290 , 151 9 / 1981 massana4 , 339 , 831 7 / 1982 johnson4 , 451 , 936 06 / 1984 carpentier , et al . 4 , 606 , 911 7 / 1986 ahmadi et al . 4 , 702 , 250 10 , 1987 levy , et al . 4 , 477 , 930 10 / 1984 totten , et al . 4 , 865 , 600 09 / 1989 carpentier , et al . 4 , 888 , 009 12 / 1989 lederman , et al . 4 , 917 , 698 4 / 1990 carpentier et al . 5 , 104 , 406 04 / 1992 curcio , et al . 5 , 104 , 407 04 / 1992 lam et al . ______________________________________ tsakiris ag . &# 34 ; the physiology of the mitral valve annulus &# 34 ;. in the mitral valve -- a pluridisciplinary approach . ed kalmanson d . publishing sciences group , action , ma ., pg 21 , 1976 . getter m ., kronzon i ., slater j . et al . &# 34 ; long - term follow - up after mitral valve reconstruction : incidence of postoperative left ventricular outflow obstruction &# 34 ;. circulation , 74 : i - 99 , 1986 . carpentier a ., deloche a ., hanania g ., et al . surgical management of acquired tricuspid valve disease . 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