U.S. patent application number 10/210085 was filed with the patent office on 2003-02-20 for implant implantation unit and procedure for implanting the unit.
Invention is credited to Philipp, Bonhoeffer, Younes, Boudjemline.
Application Number | 20030036791 10/210085 |
Document ID | / |
Family ID | 39495673 |
Filed Date | 2003-02-20 |
United States Patent
Application |
20030036791 |
Kind Code |
A1 |
Philipp, Bonhoeffer ; et
al. |
February 20, 2003 |
Implant implantation unit and procedure for implanting the unit
Abstract
The implant. implantation unit (2), at a determined position in
the tubular element (51) with a wall comprising a cavity (50), is
pushed there by a catheter (60) and the unit comprises deformable
feelers (31) to, under the control of remote activation elements
(42), change from a stowed form to a deployed functional form, to
detect the cavity (50) and position itself there with reference to
the position of the cavity.
Inventors: |
Philipp, Bonhoeffer; (Paris,
FR) ; Younes, Boudjemline; (Creteil, FR) |
Correspondence
Address: |
Finnegan, Henderson, Farabow,
Garrett & Dunner, L.L.P.
1300 I Street, N.W.
Washington
DC
20005-3315
US
|
Family ID: |
39495673 |
Appl. No.: |
10/210085 |
Filed: |
August 2, 2002 |
Current U.S.
Class: |
623/1.11 |
Current CPC
Class: |
A61F 2250/001 20130101;
A61F 2/2436 20130101; A61F 2002/061 20130101; A61F 2/2418 20130101;
A61F 2230/0054 20130101; A61F 2/2427 20130101; A61F 2/2409
20130101 |
Class at
Publication: |
623/1.11 |
International
Class: |
A61F 002/06 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 3, 2001 |
FR |
01 10444 |
Claims
1. Unit for implantation of an implant (2) at a determined position
in a tubular element (51) with a wall comprising a cavity (50,52),
the unit (10) being arranged to work with driving means (60) to
drive the unit into the tubular element (51), the unit
characterised by the fact that it comprises deployable feeler means
(30, 31, 131) arranged to, under the control of remote control
means (42), change from a stowed form to a functional deployed
form, to detect the cavity (50, 52) and position themselves there
with reference to the position of the cavity (50, 52).
2. A unit in accordance with claim 1, in which the feeler means
(30, 31) are made from a shape memory material.
3. A unit in accordance with one of the claims 1 and 2, in which
the remote control means are detachable and comprise a retaining
sleeve (42) to hold the feeler means (30, 31) in the stowed form,
said sleeve extending over the feeler means (30,31) to free them by
relative withdrawal of the sleeve relative to a wire unit thrust
drive element (60).
4. A unit in accordance with one of the claims 1 to 3, in which the
feeler means (30, 31) comprise a ring, of generally cylindrical
form with a radial direction, of loops (31) made of a wire with a
limited stiffness in the radial direction, at least one of the
loops (31) being arranged to protrude laterally so as to make a
feeler.
5. A unit in accordance with one of the claims 1 to 4, in which the
feeler means (30, 31) comprrise a plurality of feeler fingers (31)
regularly spaced angularly and arranged so that, in the deployed
form, they extend in respective inclined directions, at acute
angles to a longitudinal drive axis (62) forward from the unit
towards the cavity (50)
6. A unit according to one of claims 1 to 5, in which the feeler
means (30, 31) are joined to deformable means (20), to hold an
implant (2), arranged so that, under the action of release means
(41), it changes from a stowed form to a radially deployed form,
pressed against the wall of the tubular element (51) and bringing
the implant (2) into use.
7. A unit according to claims 3 and 6 together, in which the means.
(20) to receive the implant (2) comprise a mesh in a generally
cylindrical form having an axial direction, to carry the implant,
with a limited rigidity in the axial. direction, and the release
means include a moveable sleeve (41) to retain the carrier mesh
(20) in the stowed position, extending axially above the mesh to
release it by a relative axial withdrawal of the sleeve (42)
connected to a wire unit thrust drive element (60), the retention
and holding sleeves (41, 42) being concentric.
8. A unit in accordance with one of the claims 6 and 7, in which
the implant reception means (20) are covered with a lateral sealing
sleeve (21) intended to be pressed against the wall of the tubular
element (51) by said implant reception means (20) and the sleeve
sealing casing (21) occupies an angular position determined
relative to the feeler means.
9. A unit in accordance with one of claims 1 to 8, in which the
feeler means (131) comprise a cylindrical element arranged to
change from a stowed form to a radially deployed form arranged for
pushing against a wall of the cavity (52) under the effect of
remote control means.
10. A procedure, non surgical and with non therapeutic aims, of
implanting a unit (10) according to claim 1, in a determined
position in a tubular element with a wall (51) comprising a cavity
(50, 52), the procedure characterised by the fact that a user
inserts the unit (10) by an open end of the tubular element, the
user activates the drive means (60) to make the unit (10) move
forward to a position upstream the determined position, the user
commands the feeler means (30, 31, 131), remote control means (42),
and with the forward motion continuing, the user stops the
activation of the drive means (60) when he detects that the motion
is blocked, due to the fact that the feeler means 30, 31, 131) are
positioned in the cavity (50, 52).
Description
TECHNICAL FIELD
[0001] The current invention relates to an implant implantation
unit and to a procedure for fitting the unit in a tubular
element.
[0002] The problem at the origin of the invention concerns the
implantation of heart valves. Until recently this necessitated open
heart surgical operations, with stages such as stopping the heart,
the implementation of extra bodily blood circulation and restarting
the heart after the implantation of replacement heart valves. These
surgical operations are difficult and delicate and present mortal
risks related to operating shocks.
PRIOR ART
[0003] Document U.S. Pat. No. 5,824,063 thus describes a unit
carrying replacement heart valves, the unit comprising a tubular
implant in synthetic material carrying internally a replacement
valve in natural material.
[0004] Documents U.S. Pat. No. 5,855,601 and U.S. Pat. No.
5,868,783 describe new heart valve implantation methods, which
offer the advantage of avoiding open heart surgery. These methods
provide the implantation, by movement through the blood circulation
system, of a heart valve replacement unit comprising a radially
expandable intra-vascular cylinder carrying a biological valve
internally. An inflatable part of a balloon catheter is placed
inside the carrier cylinder and the implantation is done by
introduction into a vein and movement as far as the failed valve
using A catheter. A two dimensional image screen display allows the
detection that the carrier cylinder has reached the required
position and the cylinder is then dilated by inflating the balloon
through the catheter and maintains its expanded shape. The balloon
is then deflated and withdrawn with the catheter.
[0005] The carrier cylinder presents a sealed casing, which is thus
forced against the artery wall, so as to avoid the blood flow
bypassing the replacement valve.
[0006] However, when the aorta is involved this procedure is not
applicable because the coronary arteries open close to the failed
native valves, so that the carrier cylinder is likely to block
them, provoking the death of the patient.
AIM OF THE INVENTION
[0007] The inventors of the present application have therefore
thought of providing two corresponding openings in the wall of the
carrier cylinder casing. However, so that these openings will be
placed opposite the two coronaries, the position of the carrier
cylinder in the aorta must be completely controlled. Monitoring on
the screen allows the progress, or axial position, of the carrier
cylinder to be checked, but the angular position will be neither
visible nor controlled.
[0008] The applicants have therefore found a solution, described
below, allowing the position of the carrier cylinder to be
controlled.
[0009] They have therefore thought about the resolution of the more
general problem of positioning an implant unit or transport vehicle
in a tubular element with difficult access and for which imaging is
insufficient or even impossible. The field of application could
thus concern other fields than the medical, such as the petroleum
or nuclear industries, for installing sensors, valves and other
items. The scope of the present application must therefore not be
considered as limited to the resolution of the original problem. In
a more general way, the invention aims to allow, the placing, in a
difficult to access location of a tubular element, of a unit
intended to carry an implant, whatever the function of the
implant.
SUMMARY OF THE INVENTION
[0010] To this end, the invention concerns in the first place a
unit for the implantation in a determined position of a tubular
element with a wall comprising a cavity, the unit being arranged to
cooperate with means for driving the unit in the tubular element, a
unit characterised by the fact that it comprises deformable feelers
arranged so that, under the control of means for remote activation,
it passes from a stowed to a deployed functional shape, to detect
the cavity and position itself there with reference to the position
of the cavity.
[0011] Thus, the unit can be made to advance blind and the feelers
allow the automatic detection of the cavity and positioning at
it.
[0012] The final required position can also be reached even through
a contraction of the tubular element for example an access artery
leading to an artery of larger diameter.
[0013] The invention also concerns a process, which is not surgical
and without therapeutic aim, for implantation of the inventive
unit, at a predetermined position in a tubular element presenting a
wall comprising a cavity which procedure is characterised by the
fact that
[0014] a user inserts the unit through an open end of the tubular
element
[0015] he activates drive means to make the unit advance to a
position before the determined position,
[0016] he commands the feeler remote activation means and, with the
advance continuing,
[0017] he stops the action of the drive means when he detects a
blockage of the advance, indicating that the feeler means are
positioned in the cavity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The characteristics and advantages of the present invention
will appear more clearly with the aid of the following description
of a particular form of the realisation of the inventive unit and a
variant, as well as the procedure for using it, with reference to
the attached drawing, in which:
[0019] FIG. 1 is a lateral cross section of the inventive unit,
representing the feeler positioning and anchoring elements,
associated with a cylinder carrying a valve prosthesis, the whole
being covered by two removable concentric activation casings,
[0020] FIG. 2 corresponds to FIG. 1, the feeler positioning and
anchoring elements having been deployed radially by axial
withdrawal of the external casing,
[0021] FIG. 3 corresponds to FIGS. 1 and 2, with the carrier
cylinder surrounded by positioning and anchoring feeler elements
having been deployed radially after axial withdrawal of the
internal casing,
[0022] FIG. 4 is a lateral view of the carrier cylinder and the
positioning and anchoring feeler elements,
[0023] FIG. 5 is a lateral perspective view of the positioning and
anchoring feeler elements,
[0024] FIG. 6 is a schematic face view of the inventive unit,
and
[0025] FIG. 7 is a schematic lateral section of the variant.
DETAILED DESCRIPTION
[0026] As shown in FIG. 1, the present implementation example
corresponds to the medical problem, explained at the beginning, of
implanting a functioning replacement valve for the native aorta
valve. The valve implantation unit 10 comprises a carrier element
20 to hold the implant, joined to a plurality of feeler, or
palpation, elements or fingers 30, 31, here regularly spaced
angularly all around, for positioning and anchoring relative to
relief features, specifically a cavity in the aorta wall, unit 10
being linked removably to a positioning catheter 60. Unit 10 is
associated with two concentric sleeves 41, 42 for successive remote
activation, by radial expansion, of feeler elements 30, 31 then the
carrier element 20. The direction of movement of unit 10 is
therefore towards the left in FIGS. 1 to 3. Reference 62 represents
an axis of symmetry and the drive direction of unit 10 and catheter
60.
[0027] The implantation valve forms a prosthesis 1 comprising valve
units 2 of the valve whose shape and size correspond perfectly, in
the operating position, to those of the native aorta valves 50
(FIG. 2). The prosthesis 1 is fixed to the implant holding carrier
vehicle element 20, here comprising a cylindrical mesh in a
bio-compatible material such as steel, gold alloys and for
preference as here, nitinol, which comprises a shape memory
nickel-titanium alloy offering the ability to regain its shape
after initial deformation, here by radial compression. The fixing
of prosthesis 1 to the cylindrical nitinol mesh is made in well
defined locations leaving free those regions that correspond to the
valve units 2 after deployment from the stowed position of FIG. 2,
as illustrated below in respect of FIG. 3.
[0028] FIG. 4 represents the cylindrical mesh 20 in the deployed
form, carrying the valve units 2 also deployed internally, on which
are connected the feeler elements 30, 31, here in the form of a
generally cylindrical exterior ring of wire loops of which one (31)
at least, here in fact three, protrudes laterally and towards the
front, opposite the catheter 60. In this example, the loops 31
extend, in the deployed position, in a direction inclined at about
30 degrees towards the front (direction of movement towards the
target position) relative to the axis 62 of the mesh 20 and the
ring 30. The feeler elements 30, 31 are joined to the cylindrical
mesh 20 in such a way that their axial and angular positions
relative to it are perfectly defined. The assembly, cylindrical
mesh 2 and feeler elements 30, 31, is here composed of the auto
expandable bio-compatible material mentioned above.
[0029] The cylindrical carrier mesh 20 is here covered with an
impermeable lateral casing intended to be pressed against the aorta
wall to avoid bypassing by the blood circulation.
[0030] FIG. 5 shows the feeler elements 30, 31 in perspective. FIG.
6 is a schematic view, along the unit 10 axial direction, showing
the three loops 31 protruding laterally from the tubular grid 20
that carries them, while the 2 valve units of the valve to be
implanted are fixed internally to the carrier cylinder 20.
[0031] In addition, if necessary, an inflatable balloon, joined to
the catheter 60, can here be placed inside the carrier cylinder 20,
to be fed with liquid under pressure through catheter pipe 60 so as
to cause or assist the radial expansion of the carrier cylinder 20
to the required deployed form.
[0032] As the feeler elements 30, 31 are made in a self expanding
material such as nitinol, or an equivalent element forming an
elastically protruding foot or finger, unit 10 is covered with an
inhibition sleeve 42 to hold the feeler elements 30, 31 in a stowed
position, the loops 31 being folded on the ring 30 and thus also on
the mesh 20. Sleeve 42 extends to cover the catheter 60. A second
sleeve 41, effectively the same length and without effect on the
feeler elements 30, 31, is here similarly provided to hold the
carrier cylinder 20 in the stowed position, so as to avoid
unplanned deployment even in the absence of inflation of the
balloon 3. The two sleeves 41, 42, are mounted concentrically on
the catheter 60. The sleeves 41 and 42 are accessible from the end
of catheter 60 opposite to the unit 10. Elements 3, 41, 42, and 60
comprise a functional catheter assembly separable from the unit 10,
for the positioning and switching on this latter and the payload
(2).
[0033] The two sleeves 41, 42 inhibit the radial deployment or the
structure 20, 30, 31 until the latter reaches the region of the
native aorta valve 50 to be functionally replaced, and thus allow
the introduction of unit 10 into the blood circulation system, such
as a reduced diameter incised artery. As indicated, the catheter
60, with balloon 3, is detachably joined to the implantation unit
10 so as to allow an axial advance of the implantation unit 10 in
the blood circulation system up to the implantation location, and
the withdrawal of the catheter assembly 3, 41, 42, 60.
[0034] To free itself, the catheter 60 comprises, in this example,
at the fixed end of carrier cylinder 20, a spring effect clamp (not
shown), with remotely controlled teeth, fitted to rotate radially,
for connection to the unit 10 and has a sliding central remote
control metal wire to axially push back the claw branches or teeth
so an to separate them radially and so free the catheter 60 of the
implantation unit 10 according to the sugar claw principle.
[0035] When the cylindrical mesh 20 is deployed, the pressure on
the aorta internal wall is provided by the shape memory effect,
which thus ensures the radial dilation of the prosthesis 1. The
failed native valve unit 50 is flattened by being pressed by the
tubular grid 20 against the aorta internal wall, each of the three
loops 31 protruding laterally having previously been engaged in
one, specifically, of the three native valve units 50 and being
similarly pressed to confirm its anchorage. The valve units 50 are
thus clamped between the mesh 20, 30 and the respective loops
31.
[0036] The implantation procedure for the unit 10 described above,
according to the preferred method of implementation, comprises the
following steps. After insertion of the implantation unit 10 into
the circulatory system, and after having pushed it using the
catheter 60 to a position above the final target position, here
precisely where the unit 10 arrives in the aorta, and so that a
large diameter space is thus offered to it, the following stage
consists of freeing the lateral loops 31, initially pressed against
the stowed mesh 20, 30. The release of the loops 31 is done by
withdrawing the external retention sleeve 42 (FIG. 2), that is to
say withdrawn whilst maintaining the thrust on the catheter 60. The
forward movement of the unit 10 continuing, the loops 31, being
then protruded laterally towards the front with respect to the
axial direction of forward movement, in opposition to the catheter
60, they form a sort of tripod and simultaneously penetrate the
three respective native valves 50, effectively identical,
comprising an arrangement of connection pockets in a complete ring
with each extending over 120 degrees, filling in total the whole of
the perimeter of the aorta internal wall 51. Each native valve unit
50 offers a rounded base.
[0037] Each lateral protrusion 31, turned towards the front,
presses against the base of the native valve unit 50 concerned, in
general in a point distant from the "lowest" point of the base,
that is to say, the furthest from the catheter 60. This is
therefore a partial stop because the axial advance of the unit 10
continues by thrust from the catheter 60, the axial thrust of the
unit 10 causing it to slide to the lowest point. The bottom of the
valve unit 50 thus comprises a sort of inclined plane guidance
track (not orthogonal to the axis (62) of the aorta) which, in
reaction to the axial forward force, creates a circumferential
reaction force causing the rotation of the unit 10 until the feeler
loop considered 31 reaches the lowest point, which corresponds to a
complete end wall (with tangential plane orthogonal to the axis
(62) of the aorta 51), and thus corresponds to the final axial and
angular position sought for the unit 10.
[0038] Each lateral protrusion 31, with rounded ends, here as a
loop, so as to be able to slide in the bottom of the valve unit 50,
thus comprises, by continuous cooperation with the variable depth
rounded base of the native valves 50, means for rotational drive of
the feeler elements 30, 31 and thus also of the cylindrical mesh
20, to which it is joined. However if the lateral protrusions 31 by
chance bump against a native valve unit 50 commissure, the
implantation unit 10 can be slightly withdrawn and the operator
twists the catheter 60 so that it pivots angularly to be able to
restart the positioning and anchoring operation.
[0039] The assembly, feeler elements 30, 31 and cylindrical mesh
20, being positioned axially and at an angle with respect to the
specific relief of the aorta comprising the native valve units so,
it is then automatically positioned with respect to the two
coronary openings (52) for which the axial and angular position
with respect to the valve units 50 is determined and known, the
valve unit--coronary axial distance evidently depending on the size
of the patient.
[0040] In the case considered here in which the three native valves
50 form a circular circumference to the aorta wall extending over
360 degrees, a single lateral protrusion is sufficient to modulo
120 degrees positioning and anchoring the cylindrical mesh 20. As
stated above, in a general case, there could only be one feeler 30,
31 working with a row of cavities or pockets covering all the
circumference of the tubular element, or even a single pocket of
cavity 50 only occupying a sector of the circumference and a
plurality of feelers 30, 31 all around the unit 10 so that one of
them fits in the cavity.
[0041] It will be noted that, in the present example, modulo 120
degrees positioning can be tolerated because the two coronaries
(52) naturally effectively show this angle. If this was not the
case, it would be necessary laterally to enlarge two openings or
serrations 22 provided in the casing 21 so that they were
positioned opposite the coronaries (52) (FIG. 4 and position marked
on FIG. 3.), or again to feel, using the feelers 31, the coronaries
(52) themselves, which also comprise cavities in the aorta 51, and
not to sense the native valve units SO. This case corresponds to
the variant described below.
[0042] Positioning thus having been effected, the following stage,
as show in FIG. 3, consists of deploying the cylindrical mesh 20
carrying internally the valve units 2 by withdrawing the internal
retaining sleeve 41, to consolidate the anchorage and change the
valve units 2 to their operational form. For the clarity of the
drawing, in particular the protrusions 31, the mesh 20 has been
represented with a relatively small diameter, whereas in fact it
matches that of the aorta 51, with a slight increase to ensure the
required lateral pressure. In the same way, two protrusions 31 have
been represented, although in fact they are separated by 120
degrees, with the plane of FIG. 3 only in reality cutting one. For
this reason, only a single coronary has been drawn (52).
[0043] The three loops 31 protruding however provide by themselves
a basic anchorage in the bottom of the pockets comprising the
native valves 50 and ensure the positional stability of the
prosthesis 1. After a few weeks, fibrous tissue will cover the
prosthesis 1, combining with the lateral protrusions 31 to further
improve the fixing.
[0044] It will be noted however that, in the deployed position of
the feeler elements 31, it is not necessary that their free ends
should be firmly pressed against the aorta 51 wall. It is
sufficient that their radial extension should be sufficient that
they hook, in passing, onto the valve units 50. Because of this,
when the feeler elements 31 are deployed, before the final
position, the later axial translation of the unit 10, up to this
position, is done without "hard" rubbing under pressure, of the
part of the loops 31 on the aorta wall 51. The latter thus does not
run any risk of damage due to scratching or piercing, the loops 31
being feelers, that follow the aorta wall 51 to detect the valve
units 50. As described above, rounded feet or lugs can also be
suitable.
[0045] The feeler loops 31 thus do not here have very firm
anchoring of the unit 10 in the aorta 51 as their main function,
because they do not aim to exert a large radial anchoring pressure.
As indicated above, this is only a basic anchoring. It is then the
radial deployment of the mesh 20 that creates, by shape memory, a
definitive radial anchoring pressure that forces the mesh 20 under
pressure against the aorta wall 51 and thus blocks any relative
movement, such as the withdrawal of the unit 10 that could be due
to blood flow, in a direction opposite to the insertion of the unit
10. The feeler elements 11 are then functionally superfluous. They
however contribute to maintaining position by pinching the valve
units 2. As the mesh offers a relatively high contact surface with
the aorta 51, any risk of damaging the latter is excluded. The
shape memory material allows the radial pressure exerted on the
aorta 51 to be precisely determined, the diameter of the latter
thus increased being then perfectly defined, which eliminates all
risk of excessive radial stress.
[0046] The inventive procedure can be implemented in non-surgical
manner and without therapeutic aims, to implant the unit 10 (or
equivalent) in a determined position in a tubular elements offering
a wall including a cavity, the procedure comprising the following
stages:
[0047] a user inserts the unit (10) into an open end to the tubular
element,
[0048] the user activates the drive means (60) (catheter, external
magnet or other) to move the unit (10) up to a position upstream
the determined position,
[0049] the user commands the feeler element (30,31) activation
means (42) and, the forward motion continuing,
[0050] the user stops the activation of the drive means (60) when
he detects a blockage of the advance, due to the fact that the
feeler means (30,31) are positioned in the cavity.
[0051] To ease the drive of the unit 10, this one can be associated
with a type of precursor rostrum 61 (FIG. 1 to 3) forming a guide,
in the form of a cylindrical element of a limited diameter, joined
to the catheter 60.
[0052] It will be noted that the implantation unit according to the
invention can, first, be implanted alone, without implant or
payload, the latter being implanted later on the implantation unit
according to the same principle. In a similar case, the inventive
unit comprises means for receiving the second support, to come, of
the implant, said means being arranged to ensure the positioning
and anchorage, both axially, by stopping, and radially, with
angular error correction means such as a finger or cavity provided
to fit with an element of matching shape in the second support.
[0053] In the variant shown in FIG. 7, the implantation unit has
the reference 110 and comprises functional elements similar to
those of unit 10, with the same references preceded by the hundred
1, which have not however all been represented, with the aim of
clarity. The cylindrical carrier element 120 is joined to a feeler
element 131 which protrudes laterally and which has the same type
of construction as the carrier element 120. In precise fashion, the
feeler element 131 appears in the form of a cylinder, stowed
radially in the rest position. When the unit 110 is pushed by the
catheter 160, towards the bottom in FIG. 7, from a position above
that shown, it engages in the coronary 52 when the free end is thus
released from contact with the internal wall of the aorta 51.
[0054] The unit 110 thus comprises a type of fork that locks by
stopping in the bifurcation between the aorta 51 and the coronary
52. When the end position is reached the two cylindrical elements
120, 131 are deployed by two balloons respectively and form a type
of two fingered glove.
[0055] Thus, during the positioning phase, the feeler 131 presents
a radially stowed form, thus with reduced diameter not risking
blocking the coronary 52. Then the feeler 131 is deployed, by
inflation of the associated remote control balloon, and constitutes
a lining, or internal `casing`, pressed against the internal wall
of the coronary 52 in accordance with the principle explained above
for the carrier cylinder 20.
[0056] It will be noted that, as 120 and 131 each occupy a
particular branch 51, 52, they can be considered as functionally
equivalent, with the two principle functions if required. Each of
them can in effect be a payload (2) carrier and can also be
considered as being a feeler, because the aorta 51 can be
considered (functionally in the context of the present invention)
as being a cavity or branch with respect to the coronary 52. Thus
the feel er means comprise a cylindrical element 131 arranged to
change from a stowed form to a radially deployed form, supported
against a wall of the cavity, here the coronary 52, under the
influence of remote control means (balloon and catheter 160),
[0057] To avoid the risks of movement of the feeler 131 into the
coupling position to the coronary 52, due to an angular error that
necessitates several attempts, it can be arranged for a guide wire
to be passed into the coronary 52 and the upper part of the aorta
51, the unit 110 being threaded above it across the feeler 131 that
is thus angularly oriented towards the coronary 52. Another guide
wire can at the same time guide cylinder 120 into the aorta 51.
* * * * *