Flexible hollow guiding member with means for fluid communication therethrough

A guiding member for use as an independent guidewire or as an integral part of a low-profile steerable dilatation catheter. The guiding member has an elongated main hollow tubular member, a tubular extension preferably made of polyimide secured to the distal end of the tubular member, a core member which is secured by the proximal end thereof within the inner lumen of the main tubular member and which extends through and out the distal end of the tubular extension and a flexible body, such as a helical coil, disposed about and secured to the distal portion of the core member which extends out the distal end of the tubular extension. The transverse cross-sectional area of the core member disposed within the inner lumen of the main tubular member should be at least 10%, preferably at least 25% less than the transverse cross-sectional area of the inner lumen of the main tubular member. The distal tip of the main tubular member is at least 15 cm, preferably between 25 and 60 cm proximal to the distal end of the coil to ensure that the transition region where the core member and the tubular extension join the main tubular member remains within the guiding catheter during vascular procedures therewith. When employed as part of a steerable catheter, the inflatable balloon is secured by the proximal end thereof to the distal end of the tubular extension and by the distal end of the core member which extends therethrough.

This invention generally relates to guiding members for the advancement of 
catheters within a patient's vascular system in procedures such as 
percutaneous transluminal coronary angioplasty (PTCA) and particularly to 
such guiding members which facilitate the monitoring of pressure at the 
distal end thereof or the delivery of inflation fluid to a dilatation 
balloon. 
In typical PTCA procedures a guiding catheter having a preformed distal tip 
is percutaneously introduced into the cardiovascular system of a patient 
and advanced therein until the distal tip thereof is in one of the 
patient's coronary arteries. A guidewire is introduced through the guiding 
catheter and advanced out of the distal end of the guiding catheter and 
into the patient's coronary vasculature until the distal end of the 
guidewire crosses a lesion to be dilated. A dilatation catheter having an 
inflatable balloon on the distal portion thereof is then advanced into the 
patient's coronary anatomy over the previously introduced guidewire, with 
the guidewire slidably disposed within an inner lumen of the dilatation 
catheter, until the dilatation balloon is properly positioned across the 
lesion. Once in position across the lesion, the balloon is inflated to a 
predetermined size with radiopaque liquid at relatively high pressures 
(e.g., greater than 4 atmospheres) to compress the atherosclerotic plaque 
of the lesion against the inside of the artery wall. The balloon is then 
deflated so that the dilatation catheter can be removed and blood flow 
resumed through the dilated artery. 
Steerable dilatation catheters with built-in guiding members are being used 
with increasing frequency because the deflated profiles of such catheters 
are generally much smaller than conventional dilatation catheters and a 
smaller profile allows the catheter to cross tighter lesions and to be 
advanced much deeper into the patient's coronary anatomy. Additionally, 
the use of steerable low-profile dilatation catheters can shorten the time 
for the angioplasty procedures because there is no need to first advance a 
guidewire through the stenosis and then advance a conventional dilatation 
catheter over the previously placed guidewire. 
Further details of dilatation catheters, guidewires, and the like for 
angioplasty procedures can be found in U.S. Pat. No. 4,323,071 
(Simpson-Robert); U.S. Pat. No. 4,439,185 (Lundquist); U.S. Pat. No. 
4,468,224 (Enzmann et al.); U.S. Pat. No. 4,516,972 (Samson), U.S. Pat. 
No. 4,538,622 (Samson et al.); U.S. Pat. No. 4,582,181 (Samson); U.S. Pat. 
No. 4,616,652 (Simpson); U.S. Pat. No. 4,619,263 (Frisbie et al.) U.S. 
Pat. No. 4,638,805 (Powell); U.S. Pat. No. 4,641,654 (Samson et al.); U.S. 
Pat. No. 4,721,117 (Mar et al.); and U.S. Pat. No. 4,821,722 (Miller et 
al.) which are hereby incorporated herein in their entirety by reference 
thereto. 
Efforts have been made, such as described in U.S. Pat. No. 4,582,181, to 
develop hollow guidewire systems which allow for the measurement of the 
fluid pressure at the distal end of the catheter from the proximal end of 
the catheter. However, usually such pressure sensing guidewires do not 
have the flexibility in the distal portion thereof to be advanced very far 
into a patient's vasculature, particularly the coronary arteries. What has 
been needed and heretofore unavailable is a guiding member which has 
sufficient flexibility in the distal portion thereof to be easily advanced 
through a patient's arteries and which can monitor from the proximal end 
thereof the fluid pressure within the patient's artery at the distal end 
of the guidewire. The present invention satisfies that need. 
SUMMARY OF THE INVENTION 
The present invention is directed to an improved flexible guiding member 
which can be utilized for monitoring of fluid pressure during 
intravascular procedures such angioplasty, angiography, and valvuloplasty, 
or which can be utilized to direct inflation fluid to the interior of a 
dilatation balloon during angioplasty or valvuloplasty procedures. 
The guiding member in accordance with the invention includes a main 
elongated tubular member having an inner lumen extending therethrough to 
an axial port in the distal end thereof. A core member is secured by the 
proximal end thereof within the inner lumen of the main tubular member and 
extends out the distal end of the main tubular member. A tubular extension 
is disposed about the portion of the core member which extends out the 
distal end of the main tubular member and is secured by the proximal end 
thereof to the distal end of the main tubular member. A flexible body such 
as a helical coil is disposed about and secured to a portion of the core 
member which extends out the distal end of the tubular extension. The 
diametrical dimensions of the proximal portion of the core member disposed 
within the inner lumen of the main tubular member are substantially less 
than the smallest dimensions of the inner lumen, including the axial 
opening thereof, so as to not impede the flow of fluid therethrough or the 
passage therethrough of fluid pressure pulses. The transverse 
cross-sectional area of the core member should be at least 10% less than 
the smallest transverse cross section of the inner lumen of the main 
tubular member, preferably less than 25% of said cross-sectional area. 
When the guiding member of the invention is utilized in an independent 
guidewire configuration, the distal end of the tubular extension is bonded 
to the core member extending therethrough and preferably immediately 
adjacent the proximal end of the helical coil to provide a relatively 
smooth transition. The distal end of the tubular extension is provided 
with one or more pressure monitoring ports which connect in fluid 
communication the inner lumen of the main tubular member with the ambient 
surrounding through the inner lumen in the tubular extension. 
When the invention is utilized in a low-profile steerable dilatation 
catheter configuration, an inflatable balloon is secured by the proximal 
end thereof to the distal end of the tubular member so as to complete the 
structure of the outer catheter body. The distal end of the balloon is 
sealed about the portion of the core member which extends out the distal 
end thereof so as to prevent the loss of inflation fluid during 
angioplasty procedures. Means may be provided to vent air from the 
interior of the balloon, such as described in U.S. Pat. No. 4,638,805 
(Powell) and U.S. Pat. No. 4,821,722 (Miller et al.). 
Due to the relatively large difference in cross section between the inner 
lumen of the tubular member and the outer diameter of the proximal end of 
the core member which is secured within the inner lumen of the tubular 
member, the transition between the distal end of the main tubular member, 
the proximal end of the core member and the proximal end of the tubular 
extension does not significantly interfere with either the passage of 
fluid as when inflating a dilatation balloon on the distal end thereof or 
the passage of pressure pulses when taking pressure measurements from the 
proximal end of the tubular member. The transition region of the vascular 
device may be relatively stiff, but the effects of the relatively stiff 
transition can be minimized by disposing the transition region 
sufficiently proximal from the distal end of the guiding member to ensure 
that it remains within the guiding catheter during vascular procedures and 
that only the flexible portion of the vascular device are advanced into 
the patient's tortuous coronary anatomy. Typically, the transition region 
should be at least 25 cm, preferably at least 40 cm, from the distal tip 
of the guiding member. However, generally it should not exceed about 60 cm 
from the distal tip of the guiding member so as to not reduce the 
pushability of the distal portion of the catheter body. 
The tubular extension is diametrically relatively rigid to prevent kinking, 
but it is longitudinally more flexible than the main tubular member 
because it is this distal portion of the guiding member which must be 
advanced out of the guiding catheter into the patient's tortuous coronary 
vasculature. 
The distal portion of the guiding member in accordance with the invention 
readily advances through a patient's vasculature and particularly through 
the coronary anatomy thereof. Moreover, it provides for effective pressure 
monitoring from the proximal end thereof as a guidewire and it allows for 
the rapid inflation and deflation of a dilatation balloon on the distal 
portion thereof when the guiding member is fixed within a steerable 
catheter. These and other advantages of the invention will become more 
apparent from the following detailed description thereof when taken in 
conjunction with the accompanying exemplary drawings.

DETAILED DESCRIPTION OF THE INVENTION 
FIGS. 1-3 illustrate a guiding member embodying features of the invention 
which generally include a main tubular member 10 having an inner lumen 11, 
a longitudinally flexible tubular extension 12 having an inner lumen 13, a 
core member 14 and a helical coil 15 disposed about the distal extremity 
of the core member. The main tubular member 10 is preferably provided with 
an outer coating of a lubricious material (not shown), such as Teflon. The 
proximal end 16 of the core member 14 is secured within the distal end 17 
of the main tubular member 10 by means of a weldment 18 and has a 
transverse cross-sectional area substantially less than the smallest 
transverse cross-sectional area of the inner lumen 11 of the main tubular 
member 10. 
The tubular extension 12 is secured at its proximal end 19 to the distal 
end 17 of the main tubular member 10 and at its distal end 20 to core 
member 14 by suitable means such as adhesive 21. A plurality of pressure 
monitoring ports 22 are provided in the distal portion thereof to connect 
in fluid communication the inner lumen 11 of the main tubular member 10 
with the ambient through the inner lumen 13 of the tubular extension 12. 
The distal end 23 of core member 14 is secured to the rounded plug 24, 
preferably made of radiopaque material, at the distal end of the coil 15. 
The proximal end 25 of coil 15 is bonded by adhesive 21 to the core member 
14. The vascular device of the invention can alternatively have a "floppy" 
structure as shown in FIG. 6 and in U.S. Pat. No. 4,554,929 (Samson et 
al.), and U.S. Pat. No. 4,538,622 (Samson et al.), wherein the core member 
14 terminates short of the distal end of the coil 15 and a shaping ribbon 
46 (not shown in FIG. 1) secured to the core member extends to the rounded 
plug 24. 
The elongated main tubular member -0 is preferably made of stainless steel 
or a superelastic nickel-titanium alloy and is in the form of hypotubing. 
The core 14 is preferably a solid member formed of stainless steel. The 
helical coil 15 is preferably formed from a wire of 
palladium-platinum-molybdenum alloy or platinum-nickel alloy which has 
been gold plated. The tubular extension 12 is preferably formed from a 
polyimide, such as described in copending application Ser. No. 302,584, 
filed Jan. 26, 1989, which is hereby incorporated herein by reference. 
Suitable dimensions of the various members of the guidewire shown in FIGS. 
1-3 for coronary applications are given as follows with typical dimensions 
being provided in parentheses. The main tubular shaft 10 is generally 
about 120 to about 160 cm (140 cm) in length with an outer diameter of 
about 0.012 to about 0.018 inch (0.015 inch) and an inner diameter of 
about 0.007 to about 0.013 inch (0.01 inch). The tubular extension 12 is 
about 25 to about 45 cm (33 cm) in length with the outer diameter thereof 
from about 0.0065 to about 0.0125 inch (0.0095 inch) and the inner 
diameter from about 0.0035 to about 0.0085 inch (0.006 inch). The core 
member 14 ranges from about 25 to about 45 cm (35 cm) in length with the 
tapered section thereof being about 2 to about 6 cm (2.5 cm) in length. 
The outer diameter of the main portion of the core member 14 is about 
0.004 to about 0.012 inch (0.0065 inch) with the smallest size of the 
tapered section being rectangular in shape and about 0.0015 to about 0.004 
inch. The wire forming coil 15 is about 0.002 to about 0.003 inch (0.0025 
inch) in diameter and the coil section is about 1.5 to about 5 cm in 
length (3 cm) and has an outer diameter of about 0.01 to about 0.15 inch 
(0.0125 inch). The pressure monitoring ports 22 in the tubular extension 
12 generally number about 10 to 40 (20) and they are generally about 
0.0015 to about 0.0045 inch (0.002 inch) in diameter. Preferably, these 
ports are equally spaced in linearly arranged groups about the periphery 
of the member in which they are formed. The guidewire of the invention 
which is suitable for angioplasty will have an outer diameter from about 
0.01 to about 0.038 inch, whereas for valvuloplasty the outer diameter 
will range from about 0.025 to about 0.045 inch. 
FIGS. 4 and 5 illustrate an alternative method of joining the proximal end 
16 of the core member 14 within the distal end 17 of the main tubular 
member 10 wherein a cylindrically shaped support element 32 is secured 
within the distal end 17 of the tubular member. The proximal end 16 of the 
core member 14 is fixed within the central passageway 33 of the support 
element 32. Fluid flow passageways 34 are provided about the central 
passageway 33 to allow for fluid communication between the inner lumen 11 
of the main tubular member 10 and the inner lumen 13 of the tubular 
extension 12. The cylindrically shaped supporting element 32 may be made 
of suitable material, including plastic or metals and is fixed within the 
inner lumen 11 of the main tubular member 10 by suitable means such as 
adhesive. 
In the vascular device of the present invention, metal-to-metal bonding may 
be effected by welding, soldering, brazing and the like, whereas bonding 
to plastic materials may be effected by means of a suitable adhesive, such 
as a cyanoacrylate (Loktite 405). 
In a typical operation of a guidewire in accordance with the present 
invention, the guidewire is introduced into an inner lumen of a dilatation 
catheter and then both are advanced through a guiding catheter previously 
disposed within a patient's vasculature with the distal end of the guiding 
catheter positioned within the ostium or opening of the patient's desired 
coronary artery. The guidewire of the invention is then advanced out of 
the distal tip of the guiding catheter into the patient's coronary artery 
with the pressure monitoring ports 22 in a desired location, e.g., distal 
to the stenosis, so that pressure measurements may be taken prior to 
angioplasty procedures. The dilatation catheter may then be advanced over 
the guidewire until the balloon thereof crosses the stenosis where it is 
inflated and deflated in a normal manner to perform the dilatation. After 
deflation of the balloon, the guidewire of the invention is still in 
position with the pressure ports thereof distal to the stenosis so that 
further pressure monitoring may be made to determine the effectiveness of 
the angioplasty procedure. 
The guidewire of the invention has extensive applications in cardiovascular 
procedures, such as angioplasty, angiography, and valvuloplasty. A 
pressure gradient can be measured between the guiding catheter at the 
coronary ostium and the distal tip of the guidewire on the distal side of 
the lesion before and after the dilation of the stenotic lining. The 
present guidewire design eliminates the need for any pressure monitorings 
through the lumen of the dilatation catheter which permits the dilatation 
catheter to be constructed with a much lower profile than conventional 
dilatation catheters, thus making it possible to monitor distal pressures 
through catheters of very low profile. Accurate pressure readings can be 
obtained regardless of whether the balloon on the dilatation catheter is 
inflated or deflated. When the balloon is inflated, pressure 
determinations for the coronary anatomy distal to the inflated balloon can 
identify the presence of collateral circulation distal to the lesion and 
can identify other circulatory anomalies. The guidewire is highly 
torquable and is readily steered to facilitate placement deep within the 
patient's coronary vascular system. Moreover, there is little tendency for 
the distal portion of the guidewire, i.e., the most distal 20 to 60 cm's 
thereof, to develop a permanent curved set when passing through the curved 
distal tip of the guiding catheter, even through the tip can have a radius 
of curvature as small as 0.5 cm. 
FIGS. 6-8 illustrate an embodiment of the invention in the form of a 
low-profile steerable dilatation catheter. This embodiment is very similar 
to that shown in FIGS. 1-3 and therefore similar parts are numbered the 
same. Included is main elongated tubular member 10 within an inner lumen 
11, a tubular extension 12 secured by the proximal end 19 thereof to the 
distal end 17 of the tubular member 10, a core member 14 secured by the 
proximal end thereof within the distal end 17 of the tubular member 10, 
and an inflatable balloon member 40 which is bonded by the proximal end 41 
and distal end 42 thereof to the core member 14. 
The core member 14 is fixed to the inner wall of the main tubular member 10 
and extends distally therefrom through the inner lumens 11 and 13 and 
interior of the balloon member 40 and out the distal end thereof. A 
helical coil 15 is disposed about the portion of core member 14 which 
extends out the distal end 42 of the balloon and is secured at location 43 
and the plug 24. The proximal end or skirt 41 and the distal end or skirt 
42 of the balloon member 40 are both bonded directly or indirectly to the 
core member 14 by suitable means in order to prevent the wrapping of the 
balloon when the catheter is steered through a patient's artery to the 
site of the stenosis. 
The proximal end 41 of the balloon 40, while bonded by suitable adhesive to 
the core member 14, is radially spaced therefrom so that inflation fluid 
can pass through inlet ports 44 provided in the proximal skirt 41 into the 
interior of the balloon 40 to inflate same during angioplasty procedures. 
A radiopaque marker coil 45 is provided at the adhesive joint between the 
distal end 20 of the tubular extension 12 and the balloon 40. 
The helical coil 15 shown in FIG. 5 has a floppy construction wherein the 
longitudinal extension of the core member 14 terminates short of the 
rounded plug 24 and a shaping ribbon 46 which is secured to the core 
member 14 extends and is secured to the radiopaque rounded plug. 
As shown in FIG. 8, the proximal end 26 of tubular member 10 is provided 
with a Touhy-Borst adapter 47 to allow the tubular member to be rotated 
and to direct inflation fluid into the inner lumen 11 thereof. The adapter 
47 is of conventional construction with a housing 48 and a cap 49 
threadably connected to the housing and an annular sealing member 50 
disposed about the proximal end 26 of the main tubular member 10. The 
inner cavity within the housing 48 is tapered so that the tightening of 
the cap 49 will force the sealing member 50 against the outside of the 
proximal end 26 of the main tubular member 10 thereby effecting a 
fluid-tight seal. 
The materials of construction which are suitable for this embodiment 
generally are those which are suitable for the previously discussed 
embodiment. The shaping ribbon may be stainless steel but is preferably a 
gold plated tungsten-rhenium alloy. The balloon is preferably made of a 
biaxially oriented polymer such as polyethylene or polyethylene 
terephthalate. In the latter instance, the polymer is preferably formed 
from a thermoplastic resin having an intrinsic viscosity of about 0.75 to 
1.25, preferably less than 1.0. The wall thickness of the balloon in the 
cylindrical or working section ranges from about 0.0002 to about 0.0005 
inch, whereas in the proximal and distal ends thereof the thickness ranges 
from about 0.0008 to about 0.002 inch. 
Typical dimensions of the steerable, low-profile dilatation catheter of the 
invention include an overall length of approximately 150 to about 200 cm, 
a tip coil length from about 1 to 3 cm, a balloon length of about 1 to 3 
cm, and inflated balloon diameters from about 1 to about 5 mm. Deflated 
profiles for the balloon range from about 0.01 to about 0.025 inch (0.254 
mm 0.635 mm) preferably less than about 0.02 inch (0.508 mm). 
The low-profile steerable dilatation catheter of the invention can be used 
in the same manner as prior low-profile steerable dilatation catheters. 
However, because of the smaller profiles available with the dilatation 
catheters of the present invention, much tighter stenoses can be crossed 
than with prior devices. Moreover, the dilatation catheter of the 
invention can be readily advanced through very tortuous arterial 
passageways with little risk of wrapping the balloon on itself thus 
ensuring complete inflation and deflation when it is positioned within a 
stenosis to be dilated. Additionally, the dilatation catheter with a 
preferred profile of less than 0.02 inch can be used as described in 
copending application Ser. No. 760,636, (which is hereby incorporated 
herein by reference) to be advanced through the inner lumen of a standard 
dilatation catheter in order to first dilate a stenosis with the smaller 
dilatation catheter so that the larger profile standard dilatation 
catheter can then be advanced into the predilated stenosis to complete the 
dilatation. The Touhy-Borst adapter on the proximal end of the main 
tubular member in accordance with the invention provides the further 
advantage in that it can be removed, an exchange wire inserted into the 
proximal end of the main tubular member and the standard dilatation 
catheter can be exchanged with another standard dilatation catheter over 
the low-profile steerable catheter of the invention. Other uses of the 
invention will become apparent to those skilled in the art. 
While the above description of the invention is directed to presently 
preferred embodiments, various modifications and improvements can be made 
without departing from the scope of the invention.