IE922364A1 - Single lumen low profile valved balloon catheter - Google Patents

Abstract

A single lumen valved balloon catheter assembly caoprieing in combination: (a) a single lumen catheter having a proximal end and an open distal end and an inflatable balloon segment intermediate eaid enda and proximate the diatal and; (b) a flexible guidewire extending axially through -the lumen beyond-said opSH end, ;haid guidewire '. being axially moveable within the lumen and having a proximal segment of a first diameter and a distal segment of a second diameter that ia smaller than the first diameter, eaid first diameter being greater than the diameter of the catheter lumen diatal to the balloon; and (c) a flexible coil surrounding the guidewire within the balloon segment and having one of its enda fixed at one end of the balloon and ite other end fixed at the other and of the balloon; and (d) a valve member carried on the guidewire beyond the open distal end of the catheter and being axially moveable by axial movement of the guidewire between a first position in which the valve meofeer is axially spaced from the open distal end of the catheter to a second position in which the valve member ie seated against and blocks the open distal end of the catheter.

Description

The invention is in the general field of euzglcal instruments and relate· specifically to e aingle lumen veined balloon, catheter. —· aafiUsEsaand Balloon catheter· are used in angiography, angioplasty, and angioopdusion. They cosqprise a catheter that carrlM a distal balloon that is inflated once tha target site in a vessel is reached by the distal end of the catheter. Often the vessels through which the catheter ie paeeed ere narrow and tortuous. Zn order for tha balloon catheter to access sites ia such vessels the catheter must be flexible, torqueable and of very fine diameter. To fulfill the requirements of flexibility and torquaability catheter assenblles that include a guidewire that extends through the lumen of the catheter have been developed. In operation the guidewire ia advanced along a vessel pathway using wire torquing to orient the guidewire tip along the vessel. The catheter ia then advanced along the guidewire with tbe wire held in place.

There are two genesal type· of balloon catheter· that eogtloy guidewiras: a double lumen type and a valved aingle lumen type. The double lumen type has eonoentric .inner end outer lumens with the balloon ·ϊ· being pert of the outer lumen. The guidewire ie extended through the inner lumen.

In the single lumen valved type, the guidewire carries e distal valve aenher that can be moved by axial manipulation of tha guidewire to block the distal opening of the catheter. Commonly-owned 0.5. «,113,934 describes several eebodiments of single lumen valved catheter. Designs in which the valve ie located within the catheter lumen at the distal end of the balloon as well as design· io which the valve is located exteriorly of the lumen are shown in the patent. While these enbodimanta provided · advantages over-prior valved balloon catheters y they were not’ optimised with respect to the profile olf the distal portion of the asseafely, the sealing of the distal end of is the catheter by the valve, or the treckability of tha catheter over the guidewire.

The present invention provides a single lumen exterior located valved catheter which has improved distal portico profile, valve sealing, and treckability. 2° Diaeloaura of tha Invention Tha present invention provides a single lumen valved balloon oatheter assembly cooprislng in combination: (a) a single lumen catheter having a proximal end and an opep distal sad and an inflatable balloon segment intermediate said ends and proximate the distal end; (b) a flexible guidewire extending axially through the lumen beyond eaid open end. said guidewire being axially moveable within tha lumen and having a proximal segment of a first diaaeter and a distal segment of a second diameter that is smaller than the first diameter, said first diameter being greater than the diaaeter of the catheter lumen diatal the balloon; and (c) a flexible .coll surrounding the guidewire within the balloon segment and having one of its ends fixed et one a «nd of the balloon and it· other aad fixed at the other and of the balloons and (d) a valve member carried an the guldevire beyond the open dietal end of the catheter and being axially moveable by axial movement of the guidewlre S between a first position ia which the valve ambtr ie axially spaced from the open dietal end of the catheter to a second position in which the valve member ie eeated against and blocks the open dietal end of ehe catheter. io Briar Daigriptloa of tht owing The drawing showa aa enlarged (not to scale) sectional·' elevational view of an-embodiment of the catheter guidewire aeeeebly of this invention.

IS The drawing deplete the proximal portion, generally designated 10, and dietal portion, generally designated 12, of a catheter guldevire assesfely constructed according to one enfcodlmeat of the invention.

The two main ceapanente of the asseably, the single lumen catheter and guidewlre, are generally designated 14 aad 16, respectively. The catheter is conpoead of a flexible thin-walled tube IS having a single lumen 20 extending between prnrlmal and dietal and region· 22, 24, respectively. The proximal end of the catheter ie received la a conventional syringe fitting 26 that baa a central axial bore 2S through which the guldevire extends. The dietal end of the bore communicatee with the catheter lumen. The fitting ia also provided with a eldeport 30 that ecsmunlcatee with the central axial bore of the fitting. The proximal end of the central bore le fitted with a sealing ring 32.

The proximal end of the guldevire carries e disc-shaped torquixig handle, or grip 34 for applying torque to the guidewlre during the catheterisation procedure. 4The flexibility of the tub· is la not uniform axially. Aa shown, tha proximal segment 35 of tube IS has a thicker wall and la leaa flexible than the distal segment 38 of the tube. The transition In wall thiokneaa la shown at 40. It should be noted that tbe wall of the tube may be aede of e homogeneous materiel or It may be formed from a layered or laminated material·. In the embodiment ahown In the drawing· the wall of the proximal segment la a bilayer and the wall of the distal portion le defined by an extension of only the outer layer of the proximal segment.

- Tha wall thickness of ehe proximal. Segment, of the tube will normally be 5 mil to l4 mil, more usually IS mil to 12 all, and preferably approximately 12 mil whereas the wall thickness of tha distal segment will normally be 3 mil to β mil, more usually 4 mil to 6 mil, and preferably approximately 5 all. Tbs material (a) from which the tube is made is a medically acceptable nondistensible polymer having the appropriate mechanical properties. Preferred material· ere polyethylene, polyester, polypropylene, poly imide, polyvinyl chloride.

The outer diameter ot the proximal segment of the tube will normally be 33 ail to 56 all, store usually 34 mil to 40 mil, and preferably approximately 36 mil. Correspondingly, the outer diameter of tbe distal segment of tbe tube (except balloon) will normally be 28 mil to 36 ail, more usually 34 ail to 50 sill, and preferably approximately 32 all. The diameter of the lumen of tbe tube (up to tbe balloon) will normally he 19 mil to 25 mil, more usually 20 ail to 23 mil, and preferably approximately 22 ail.

The balloon 42 of the catheter le defined by a portion of the thin-welled distal segment of the catheter tube. In ite deflated configuration it has a disaster that approximates the diameter of the tube proximal to •5 It. It will normally be inflatable to a maximum diameter with a sang» of eiaee 1.5, 2.0, 2.5, 3.0, 3.5, 4.0 mm. There ie a diee-ehaped plug member <« fixed within the lumen of the distal segment of the tube at the proximal end of the balloon. The plug baa a central bore 45 through which the guidewire extends, λ fixed soft plastic insert 4$ ie positioned within the lumen of the segment 48 of the tube that ie distal to the distal end of the balloon, zte tip extends slightly beyond the tube end and is dimensioned to have aa low a profile ae possible for tracking over the guidewire end passing through tight veeele narrowings. -Thisinsert has a centra! bore 50’andserves to reduce‘ the diameter of the distal outlet of the balloon. Typically the inner diameter of the insert (i.e., the diameter of its bore) will be 8 mil to i2 mil, more usually 9 ail to 11 mil and preferably approximately 10 mil. he shown, the guidewire extends entirely through bore 50 and out the diaeal and of the catheter tube.

A fixed coil 52 encloses the portion of the guidewire present in the balloon. The ends of the ooil are anchored in the plug nmsfeer 44 and insert 46. The inner diemeter of the coil approximates the inner diameter of the insert 46. The coll ie made wholly or partly of e radiopaque material, such as platinum. The coil thus serves ee a means for visualising the location of the balloon within the vessel. The coil also serves to support the balloon in its deflated state.

The guidewire carries a fixed, generally spherical valve 54 proximate its distal end. It also ie wrapped with a coil 56 dietally of the valve mentoer and is terminated with a hemispherical tip 58. Further, unlike prior aaseefeliee, the guidewire used in the present invention dose not have a uniform diameter. Instead, it ie ocepoeed of a proximal segment 60 and a ,922364 -ίdiatal segment 62 of mailer dimeter than that of the proximal segment. The diameter of the proximal segment of the guidewire will usually he about 12 ell eo IB ail, more usually 14 mil, and preferably approximately 14 mil.

While the transition between the larger diameter proximal segment and the smaller diameter distal segment may be a gradual taper, for ease of. preparation it will typically be a step tmaaitioo in which there la a defined shoulder between tha two diameters. The diameter of the portion of the distal segment chat extends through bore The smaller diameter of the distal segment provldee advantages over prior valved catheter structures. The cross-sectional profile of tho distal portion of tha aaesably may be and· corresponding smaller, thus enabling access to smaller vessels. Also, tha ability of the guidewire to follow tortuous vessel paths is enhanced.

Tha portion of the catheter tube distal to the diatal end of tha balloon will normally be at least about 0.5 cm or mere ia length, typically 0.3 to 1.5 cm and preferably about 0.7 cm. Xta tip, defined by the distal end of insert <6 ia soft and elastic end that it conforms to the configuration of the valve member whan the valve 7member ia pulled back against lc ao that the valve member la able to east tightly against tha tip. Additional radiopaque material may ba incorporated closely adjacent the tip (e.g., platinum coil ¢4), to enable tha location of tha tip to ba visualised when the catheter la In the vessel.

The catheter assembly of the invention la operated In a similar fashion to other valved balloon cache tare. In such operation the guidewire le advanced into the desired vasculature to a desired site and the eatheter tubs is tracked over the guidewire. However, ' because of the etzucturerof the present?'invention, the guidewire may be extended distally only a limited distance beyond the distal end of the eatheter. That distance will be determined by the length of the reduced diameter segment of the guidewire and the length of the catheter tube that extends distally beyond tha balloon. The location of the guidewire and balloon within the vessel may be determined by conventional radiology techniques. Ones the balloon is at the desired sits within ehs vessel the catheter lumen ia flushed by Injecting fluid through the sideport >0, the valve member Is ssstsd firmly against the distal tip of tha eatheter by manipulating the guidewire axially. Thia blocks the distal opening of the catheter tube. The balloon is then inflated by injecting fluid through the sideport 30. 0Xm«.w Um I ··, -i- t bvbwvou bu« yuluewxre ana cne oxseax lumen ie small, aealiag is efficient. This small clearance also minimises the posaibillty of aspirating blood into the balloon lumen, zn addition tbe email eealing area reduces tbe likelihood of the valve and distal tip sticking together, zf desired, controlled distal leakage of fluid fro· the eatheter tip may be aahlaved by slight adjustment in the tightness of the seating between tbe valve and distal tip of the catheter. β· The balloon stay ba deflated by creating back pressure (vacuum) drawn via tha sidaport.

It ia further noted that tha guidewire ia built into the assembly (i.e., It ia not removable). Accordingly, no guidevire/valvewira exchangee are needed in clinical applications. Further, no tine le loet in loading the guidewire and the possibility of damaging the guidewire or catheter during loading le eliminated.

Hu following provides an exanple of one procedure for manufacturing a cathater-guidewire assembly according to the invention.

·- A segment of radlatlonHurdened polyethylene tubing of knoen^iheide1 diameter, i.e., 0.031 iaehea, and known outside diameter, i.e., 0.034 inches, is heated to about 300·» and pressurised inside a mold cavity of predetermined shape. The operation causes tbe heated segment to foa a balloon configuration, and Motions adjacent distally and proxlmally aa also expanded to allow the insertion of the coil (53) end the hot melt polymer tubing that holds the coil in place and forms tha restrictor (44) and insert 45 members. It· coil can have approximate inside disaster of 0.012 inches made from a material that ie fluoroscopioally visible like etainleee steel. Tbe hot melt polymer tubing is positioned over the balloon coil and ie heaeed until it has melted to hold the coil securely to the balloon tubing. This procedure is performed on both ends of the balloon segment. The segment proximal to the balloon uses a wire mandrel close to the inside diameter of the balloon coll to allow for sufficient room for adequate balloon inflation time. The segment distal to the balloon usee a wire mandrel slightly bigger than the diameter of the ground aagment of the guidewire. Ixcess tubing aaterial on the tip ie out so as to leave a concave-shaped tip. -9Ihe tubing ia than cut to aoma uaabla length, a.g., ISO ca, and la connected to a T-typa syringe assembly, one with provision to aaal the guidawira on ana and of tha assembly, and tha other should ba able to communicate with tba tubing luman on tha other and. Tha seal ing and of the T-typa aaaambly should be ln-llne with the balloon tube. The ground sagmant of the guldevlre la than threaded through tha aaal port of tha T-asaembly until tha tip pease· through tha and of tha balloon tube with sufficient clearance batvaan the tip of tha wire and tba tip of tha balloon tuba. Tba guidawire coil la than aoldarad_on thajfliatal hip of tha-wire on both anda of tha coll. rTha'holder dh the proximal and' of tha coil should be kept as uniformly hemispherical as possible.

Tha integrity of the system may ba pressure tested an follow·. The distal and of tha balloon tube la saalad by pulling on the guidawira until intimate contact between the tip of tha balloon tubing and tha proximal solder on tha wire is mads. The balloon tubing is then pressurised up to 100 psi with air while submerging the tip io a atarila liquid for five min. to datezmln· whether ie leaks.

Claims (5)

1. 5 l. λ «ingle lumen valved balloon catheter assembly comprising In combination: (a) a single lumen catheter having a proodaal end and an open distal end and an inflatable balloon segment intermediate eaid ends snd proximate the distal 10 end; (b) a flexible guidevire extending axially through the lumen beyond-auaid opts end,/laid guidevire being axially moveable within the lumen and having a proximal segment of e first diameter ead e distal segment 15 of e second diameter that ie smeller than the first diameter, said first diameter being greeter than the diameter of the catheter lumen distal to the balloon; and (c) a flexible eoll surrounding the guidevire within the balloon segment end having one of it· ends 20 fixed at one end of the balloon and its other end fixed et the other end of the balloon; and (d) a valve aenber carried on the guidevire beyond the open distal end of the catheter ead being axially moveable hy axial movement of the guidevire 25 between a first position in which the valve mssber ie axially spaced from the open distal end of the catheter to a second position in whioh the valve mmnber ie seated against end blocks the open distal end of the catheter. 30

2. The eeeembly of claim l wherein the length of said distal segment of the guidevire is at least aa long an the axial distance from the proximal and of the bellMw Lu th· valvw maeber.'

3. Th· asesmbly of claim i wherein the durance between the dietal segment of the guldewire and the catheter lumen dietal to the balloon la email.

4. 5 <. The aeeenbly of claim 1 wherein the transition between the proximal and dietal eegmenta of the guldewire le a step traneltion. 5. The aeeenbly of claim l wherein the dietal 10 tip of the catheter ia made of a eoft plaetlc that will distort and conform to the configuration of the valve member when the valve member ie preesedagainst said dietal tip. . is 6. The aeeenbly of claim S wherein the surface of the valve member that eute agalnet the dietal tip of the catheter le generally spherical. 7. The aeeenbly of claim 1 wherein at luat a 30 portion of the coil le made of a radiopaque material. I. The aeeenbly of claim l wherein the catheter oonpriaae a proximal segment having a predetermined wall thickness and flexibility and a dietal 35 segment having a leeeer wall thickness and more flexibility than the proximal segment, 9. The aeeenbly of dal* 1 where the diameter of the proximal aegment of the guldewire le 13 mil to 30 IS mil and the diameter of the dietal segment la 5 mil to 10 mil. S223

5. 6 4 -1210. An assembly according to any preceding claim substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.