Intra-aortic balloon assembly with hemostasis device

An intra-aortic balloon assembly which includes an hemostasis device slidably mounted to a balloon catheter, and method for percutaneous insertion of such assembly. The hemostasis device provides a distal constant diameter segment dimensioned to minimize initial resistance to the insertion of the hemostasis device, integrated with a second proximal segment of larger constant diameter via a transition segment. The second constant diameter segment is proportioned to fill the opening in the patient's skin created by the insertion of the intra-aortic balloon and thereby stop any bleeding from the femoral artery at the insertion site. The method includes the steps of (1) percutaneously inserting the intra-aortic balloon into the femoral common artery, with or without the use of a tear-away insertion sheath, (2) removing the insertion sheath (if one is used) after insertion of the intra-aortic balloon assembly, and (3) inserting the hemostasis device into the patient's skin at the insertion site to stop bleeding which may occur upon sheathless insertion of the wrapped balloon or removal of the insertion sheath.

BACKGROUND AND OBJECTS OF THE INVENTION 
The present invention relates generally to intra-aortic balloon 
(hereinafter "IAB") assemblies, and more particularly, to an improved IAB 
assembly and percutaneous method for inserting same employing a new 
hemostasis device to facilitate insertion of the IAB into the body by (1) 
reducing insertion time, and (2) by lowering the degree of obstruction in 
the femoral artery, while at the same time controlling bleeding back 
through the insertion site. 
IAB devices are introduced into the body and are used to assist the pumping 
action of the heart. See, for example, U.S. Pat. No. 4,362,150. In some 
instances, they may remain in the body for extended periods of time, such 
as several days or more. 
One method of installing an IAB device in the body is via non-surgical 
insertion into the femoral common artery using the percutaneous 
"Seldinger" insertion technique. In the Seldinger technique, the skin is 
punctured with a hypodermic needle to form a hole through the skin and 
into the femoral artery. A first guide wire is inserted through the needle 
into the femoral artery and the needle is then removed from the artery, 
leaving the guide wire in place. The puncture hole created by the needle 
is then expanded by an inserter dilator (for example, an 8-French dilator) 
which slides over the guide wire through the skin and into the artery. The 
inserter dilator is then removed and a series of progressively larger 
dilators are inserted into the hole over the guide wire to increase the 
size of the hole. Next, an insertion sheath is passed through the hole 
over the guide wire and into the femoral artery. This sheath has an inside 
diameter generally corresponding to the outside diameter of the IAB to be 
inserted. The first guide wire is removed and replaced by a second guide 
wire which is fed up through the artery to the vicinity of the aortic 
arch. The IAB is passed over this second guide wire and slides up through 
the insertion sheath and along the artery to a point just below the aortic 
arch. 
Although the foregoing procedure generally is a safe, rapid and efficacious 
way of intra-aortic balloon insertion, the prerequisite insertion of the 
sheath requires time and equipment to perform, often under circumstances 
such that time is a critical factor to patient survival, as during 
cardiogenic shock. During the foregoing procedure, arterial bleeding 
through the insertion sheath must be carefully controlled during the time 
interval between the removal of the first guide wire from the sheath and 
the insertion of the wrapped balloon containing the second guide wire. 
Often, especially in a hypovolemic patient, this loss of blood may be 
critical. 
Moreover, when the balloon bladder is wrapped around the central cannula, 
spiral interstices are produced along its length. The interstices of the 
wrapped balloon membrane do not provide for the complete occlusion of the 
insertion sheath between its inner wall and the wrapped balloon. 
Therefore, a certain amount of arterial bleeding takes place during the 
time that is required to fully insert the wrapped balloon membrane portion 
of the balloon catheter into the blood vessel. In some cases, the 
insertion sheath may have to be withdrawn partly from the percutaneous 
wound to permit complete introduction of the balloon membrane into the 
sheath, especially in those cases of extreme vascular tortuosity. This 
creates an additional loss of critical time and of critical blood. 
Another problem experienced with some patients is that after IAB insertion 
is complete, blood flow to the lower extremities is diminished 
substantially. The decrease in blood flow is generally attributable to the 
obstruction of the femoral artery caused by the relatively large diameter 
of the insertion sheath extending into the artery. By removing the sheath, 
the obstruction in the femoral artery can be decreased substantially. 
Certain prior art techniques attempt to solve this problem by utilizing 
splittable ("tear-away") insertion sheaths, such as, for example, those 
identified in U.S. Pat. Nos. 4,166,469, 4,581,019 and 4,581,025. Once the 
insertion sheath is removed, however, the arterial wall must constrict to 
seal around the balloon catheter (which has a smaller outside diameter 
than the insertion sheath) to prevent bleeding at the insertion site. In 
non-elastic or diseased vessels, the required vessel constriction may not 
always occur resulting in profuse bleeding at the insertion site between 
the IAB catheter and arterial puncture. If bleeding cannot be stopped, the 
IAB must be removed. One way to stop this bleeding is to exert pressure on 
the artery above the insertion site. Such an approach, however, adds an 
additional step to the IAB insertion process, and may also result in 
damage to the balloon catheter. 
In response to the foregoing problems, other approaches have been advanced 
involving the use of a tapered hemostasis device which is slidably mounted 
to the balloon catheter, and which can be inserted into the patient after 
the tear-away sheath is removed to control bleeding at the insertion site. 
See, for example, the device's identified in my co-pending U.S. patent 
application Ser. No. 53,183 and Magro et al. U.S. Pat. No. 4,738,658. The 
subject invention is an improvement over those devices. For example, due 
to the structure of such devices, a patient having limited or little 
vessel and skin elasticity will ordinarily require a greater length of the 
hemostasis device to be inserted to stop bleeding at the IAB puncture site 
than a patient whose vessels and skin are relatively elastic. As the 
length and diameter of the hemostasis device inserted increases, there 
will be an accompanying increase in both insertion time and body 
resistance to insertion. 
Accordingly, it is an object of the present invention to provide a new IAB 
assembly and method of inserting same into the body which incorporates a 
new hemostasis device for controlling bleeding at the insertion site after 
insertion of the IAB. It is another object of the present invention to 
provide a new IAB assembly including a hemostasis device which can be 
inserted into the patient using either a tear-away insertion sheath or a 
sheathless insertion technique. 
It is yet a further object of the present invention to provide a new 
hemostasis device which controls bleeding at the IAB insertion site 
without restricting good blood flow through the femoral artery to any 
great degree. It is still another object of the invention to provide a new 
IAB assembly including a hemostasis device which does not rely on a 
tapered configuration to perform the hemostasis function. 
It is still another object of the invention to provide a new hemostasis 
device providing a first constant diameter segment at the distal end 
thereof configured and dimensioned to generate less initial resistance 
during insertion into the patient's skin, and a second constant diameter 
segment positioned proximally with respect to the first segment which is 
dimensioned to fill the opening in the patient's skin created by the 
insertion of the IAB device, and thereby stop bleeding from the femoral 
artery at the insertion site. 
It is still a further object of the present invention to provide a new 
hemostasis device including a transition segment connecting the first and 
second constant diameters segments which allows essentially immediate 
transition from the first segment to the second segment during insertion 
of the hemostasis device, yet at the same time minimizes any resistance 
encountered during insertion of the second larger diameter segment through 
the patient's skin. 
The foregoing specific objects and advantages of the invention are 
illustrative of those which can be achieved by the present invention and 
are not intended to be exhaustive or limiting of the possible advantages 
which can be realized. Thus, these and other objects and advantages of the 
invention will be apparent from the description herein or can be learned 
from practicing the invention, both as embodied herein or as modified in 
view of any variations which may be apparent to those skilled in the art. 
Accordingly, the present invention resides in the novel parts, 
constructions, arrangements, combinations and improvement herein shown and 
described. 
SUMMARY OF THE INVENTION 
Briefly described, the present invention comprises an IAB assembly and 
method for inserting same into the body in which the assembly incorporates 
a hemostasis device slidably mounted to the balloon catheter for 
controlling bleeding from the insertion site after insertion of the IAB. 
According to one specific aspect of the invention, the hemostasis device is 
formed with a first constant diameter segment at the distal end thereof 
which is only slightly larger in diameter than the outside diameter of the 
balloon catheter, and which is dimensioned to be as small as possible so 
as to pass through the opening made by the passage of the balloon bladder 
through the percutaneous insertion site and into the femoral artery. 
According to another specific aspect of the invention, the first segment of 
the hemostasis device is integrated with a second constant diameter 
segment positioned proximally with respect thereto via a transition 
segment. As preferably embodied, the second constant diameter segment is 
proportioned to fill the opening in the patient's skin at the percutaneous 
insertion site upon slidable insertion of the hemostasis device thereinto, 
and thereby stop bleeding from the femoral artery at the insertion site. 
According to the invention, the transition segment is configured and 
dimensioned so as to allow essentially immediate transition from the first 
segment to the second segment during insertion of the hemostasis device, 
yet at the same time minimize any resistance encountered during insertion 
of the larger diameter second segment through the patient's skin. 
As here embodied, the inside diameter of the hemostasis device is sized to 
provide a close clearance between the inside of the hemostasis device at 
its distal end and the outside of the balloon catheter. Preferably, the 
inside diameter of the hemostasis device should be sized so as to maintain 
this close tolerance, yet at the same time permit the sheath to be easily 
slidably translated along the balloon catheter to and from the 
percutaneous insertion site. 
According to another specific aspect of the invention, the hemostasis 
device is provided with a cuff member releasably attachable to the 
proximal end thereof to prevent any residual backflow of blood from 
spurting out of the sheath while it is being inserted into the femoral 
artery. According to another specific aspect of the invention, the 
hemostasis device can be used in conjunction with an IAB apparatus 
inserted into the patient using either a tear-away insertion sheath or 
using a sheathless insertion technique. 
It will be appreciated by those skilled in the art that the foregoing brief 
description and the following detailed description are exemplary and 
explanatory of the present invention, but are not intended to be 
restrictive thereof or limiting of the advantages which can be achieved by 
the invention. Thus, the accompanying drawings, referred to herein and 
constituting a part thereof, illustrate preferred embodiments of the 
invention and, together with the detailed description, serve to explain 
the principles of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the accompanying drawings wherein like reference 
characters refer to like parts throughout the various views, there is 
shown in FIG. 1 lines (a-d) the various steps employed in the Seldinger 
technique for inserting an IAB device percutaneously, and in FIGS. 2a 
through 6, the preferred embodiments of the IAB assembly with hemostasis 
device and method for percutaneous insertion of same according to the 
present invention. 
Referring first to FIGS. 1 lines (a-d), FIG. 1 line (a) shows puncture of 
the skin and the femoral artery using a Seldinger needle. FIG. 1 line (b) 
shows placement of a guide wire 5 into the artery through the hollow bore 
of the needle. FIG. 1 line (c) shows removal of the hypodermic needle from 
the artery leaving the guide wire 5 in place. Finally, FIG. 1 line (d) 
shows placement of an insertion sheath into the artery over the guide wire 
following dilation of the insertion site. 
Referring now to FIGS. 2a, 2b, and 5, there is shown the insertion of an 
IAB assembly with hemostasis device according to the invention into a 
femoral common artery through the skin using a new percutaneous insertion 
technique also according to the invention. With reference to these 
figures, a physician (not shown) would be positioned in the left-hand 
margin in relation to the various elements being described. The terms 
"proximal" and "distal" as used herein shall refer to position a relative 
to that of the physician. 
Referring particularly to FIGS. 2a and 2b, the IAB assembly comprises and 
IAB bladder 40 which is attached to a balloon catheter 42. The IAB is a 
double lumen device with a central cannula 44 preferably of, but not 
limited to, the type described in U.S. Pat. No. 4,362,150, which patent is 
incorporated herein by reference. The IAB can have a wrap handle for 
rotation as described in the above patent or can have a fixed type 
configuration. 
Prior to insertion, the bladder 40 is wrapped about itself to reduce its 
diameter either by the manufacturer or by the physician. As will be 
recognized by those skilled in the art, the balloon catheter 42 may be 
attached at its proximal end to a rotating or fixed handle (not shown) and 
may also be connected in known manner to an intra-aortic balloon 
pumping/monitoring system (also not shown). 
Referring now to FIG. 6, there is shown a preferred embodiment of 
hemostasis device 50 in accordance with the present invention. As shown in 
FIG. 6, hemostasis device 50 is slidably mounted to balloon catheter 42 
and generally comprises a the distal end of the device, a second segment 
50b positioned proximally with respect to first segment 50a and formed 
with a neck portion 55, a transition segment 50c connecting segments 50a 
and 50b together, a flange 57 formed on segment 50b at the proximal end of 
the hemostasis device, and a cuff 60 releasably connectable to flange 57. 
As preferably embodied, the hemostasis device is manufactured from a 
resilient plastic material, such as polytetrafluoroethylene (Teflon.RTM.) 
or polyethylene. According to the invention, the cuff 60 is manufactured 
from an elastomeric material such as, for example, Kraton; although no 
particular elastomeric material is preferred. 
As preferably embodied, first segment 50a has a constant outside diameter 
which is only slightly larger than the outside diameter of catheter 42, 
and which is dimensioned to be as small as possible so as to pass through 
the opening made by the passage of balloon bladder 40 through the 
percutaneous insertion site and into the femoral artery. For example, in a 
preferred embodiment of the invention wherein the outside diameter of the 
balloon catheter is about 10.5 French (i.e. about 0.138 inches), the 
outside diameter (A) of segment 50a (see FIG. 6) is about 0.150 inches. 
Similarly, for a 9.5 French balloon catheter (i.e. about 0.128 inches in 
diameter), the outside diameter (A) of segment 50a is about 0.142 inches. 
As here embodied, segment 50a preferably has a length of at least about 
1/8 inch, and is configured and dimensioned to generate less initial 
resistance during insertion through the patient's skin so that the 
hemostasis device as a whole can be more easily inserted into the patient. 
Although the overall resistance to further insertion will increase as 
larger diameter segment 50b of the hemostasis device (described below) is 
inserted, the safe passage of segment 50a through the skin will avoid the 
danger of collapsing or buckling of the hemostasis device at its distal 
end. 
To control bleeding at the insertion site during and after insertion of the 
balloon bladder, hemostasis device 50 of the present invention is provided 
with a second segment 50b connected to segment 50a via a transition 
segment 50c. As preferably embodied, segment 50b has a constant outside 
diameter dimensioned to be larger than the outside diameter of the wrapped 
balloon 40. This will enable segment 50b to fill the opening in the 
patient's skin created by the insertion of balloon 40 into the patient's 
femoral artery and thereby stop bleeding from the femoral artery at the 
insertion site. As here embodied, the outside diameter of segment 50b is 
preferably about 0.169 inches. This will provide adequate hemostasis 
capability for all commercially available IAB assemblies; the largest 
being a 50 cc assembly wherein the outside diameter of the wrapped balloon 
is about 0.162 inches. 
According to the invention, transition segment 50c is configured and 
dimensioned so as to allow essentially immediate transition from first 
segment 50a to second segment 50b during insertion of hemostasis device 50 
into the percutaneous insertion site opening, yet at the same time 
minimize any resistance encountered during insertion of larger diameter 
segment 50b through the patient's skin. As preferably embodied, transition 
segment 50c has a tapered configuration and a length of about 1/8 inch 
measured linearly from the end of segment 50a to the beginning of segment 
50b. Although the angle of taper for segment 50c will vary in accordance 
with the dimensions of segments 50a and 50b employed, it is preferred that 
transition segment 50c be tapered in a manner so as to provide the 
smoothest and quickest transition from first segment 50a to second segment 
50b during the insertion process. Because transition segment 50c does not 
perform a hemostasis function, it may, in accordance with the invention, 
be omitted from the hemostasis device structure (with second segment 50b 
immediately following first segment 50a). Such an arrangement, however, is 
less preferred as it will result in increased resistance to insertion of 
the hemostasis device into the patient. 
As preferably embodied, the length of segment 50b is about 2.75 inches, 
thereby giving hemostasis device 50 an overall length (T) between distal 
end 52 and proximal end 54 of preferably about 3.0 inches. Advantageously, 
because the combined length of hemostasis device entering the patient 
prior to segment 50b is on the order of only about 1/4 of an inch (i.e. 
the combined length of first segment 50a and transition segment 50c), 
obstruction to continued blood flow along the femoral artery caused by the 
insertion of the hemostasis device, as well as the body's resistance to 
insertion of the hemostasis device, will both be minimized. 
As here embodied, the inside diameter (I) of hemostasis device 50 can be 
about the same throughout its entire length (as shown in FIG. 6), or can 
vary in accordance with the configuration of the outside of hemostasis 
device 50. In any event, the inside diameter of device 50 is preferably 
sized to provide a close clearance 58 between the inside of the hemostasis 
device 50 at distal end 52 and the outside of the balloon catheter 42. 
Preferably, the inside diameter (I) of hemostasis device 50 at distal end 
52 is between about 2 to 3 thousandths of an inch larger than the outside 
diameter of the balloon catheter 42 to allow for manufacturing tolerance. 
For example, in a preferred embodiment of the invention wherein the 
outside diameter of the balloon catheter is about 10.5 French (i.e., about 
0.138 inches), the inside diameter (I) of the hemostasis device 50 at the 
distal end 52 is about 0.140 inches to provide a clearance 58 of about 
0.002 inches between the hemostasis device and the catheter. 
More preferably, in view of the resilience of the materials utilized, one 
can maintain an interference fit between balloon catheter 42 and 
hemostasis device 50 such that the inside diameter (I) of the hemostasis 
device is essentially the same as the outside diameter of the balloon 
catheter. This close fit clearance 58 permits the outside diameter of 
hemostasis device 50 to be as small as possible at the distal end 52 with 
the balloon catheter 42 providing structural support for the hemostasis 
device 50 during insertion to prevent an accordion effect from occurring 
at distal end 52. Advantageously, the resilient, low-friction nature of 
the hemostasis device material allows the device to be easily slidably 
advanced along the catheter in either a distal or proximal direction 
substantially without loosening the interference fit between the parts. 
According to the invention, hemostasis device 50 is provided at its 
proximal end with a neck 55 and flange 57, each formed on second segment 
50b. As here embodied, neck 55 and flange 57 are held within a cuff member 
60. As shown in FIG. 6, cuff 60 is sized to provide a close clearance 64 
between the cuff and neck 55 of the hemostasis device. Additionally, cuff 
60 is sized to provide a close clearance 62 between the cuff and balloon 
catheter 42. In this manner, cuff 60 is able to seal the proximal end of 
hemostasis device 50 against backflow of blood through the device after it 
has been inserted into the femoral artery. Close clearance 62 also 
precludes slippage of cuff 60 and, in turn, hemostasis device 50 along 
catheter 42 due to arterial pressure and the like. 
Operation of the hemostasis device 50 is relatively straightforward. An 
insertion technique according to the invention using the hemostasis device 
will now be described. Referring to FIG. 2a, a small hypodermic needle 
(not shown) is inserted through the skin 20 of a patient to perforate or 
puncture the femoral artery 10. When blood spurts from the open external 
end of the needle, placement of the hypodermic needle within the artery 10 
is confirmed. A guide wire 5 sufficient in length to reach the central 
aorta (e.g. up to about 170-190 cm or longer) is fed into the artery 10 by 
passing the guide wire through the center of the hollow hypodermic needle. 
Next, the hypodermic needle is removed leaving the guide wire 5 in place. 
One or more progressively larger dilators (preferably a single expanding, 
e.g. Grunzig type dilator) is then placed over the guide wire and advanced 
through the perforated skin 20 and into the artery 10 in order to expand 
the hole to achieve an opening large enough to permit the passage of the 
wrapped IAB bladder 40. For example, when using a 10.5 French IAB the hole 
should be dilated to approximately 10 French in diameter. Once the skin 20 
and artery 10 have been fully dilated, the dilator is removed and the IAB 
device is inserted directly into the patient without passing it through an 
insertion sheath. 
Still referring to FIG. 2a, the IAB bladder 40 in its wrapped condition has 
a larger outside diameter than the IAB catheter 42. As a result, the IAB 
bladder 40 will dilate the insertion site to a larger diameter than that 
of the catheter 42. As can be seen in FIG. 2b, after passage of the IAB 
the insertion site 8 may have an opening which, due to some inelasticity 
in the skin, has not completely closed around the catheter 42. This 
condition may result in uncontrollable bleeding from the insertion site. 
As a means to diminish bleeding when it occurs, hemostasis device 50 is 
slidably advanced in a distal direction along catheter 42 so as to insert 
first segment 50a thereof into opening 14 in the wall of femoral artery 10 
made by passage of the IAB balloon bladder thereinto. Hemostasis device 50 
is further advanced into the femoral artery until segment 50b thereof 
fills opening 14 (see FIG. 5). In this position, the outside diameter of 
segment 50b will sufficiently fill opening 14 so as to provide elastic, 
sealing contact between the skin opening and segment 50b, and thereby stop 
bleeding which might have resulted after insertion of the IAB device. The 
configuration and dimensions of the hemostasis device (described above) 
control bleeding without restricting good blood flow through artery 10 to 
any great degree. Moreover, any residual backflow of blood up through 
device 50 during the insertion process will be prevented from spurting out 
of the hemostasis device via cuff member 60. 
Referring now to FIGS. 3-5, an alternative IAB insertion technique 
according to the invention using a tear-away insertion sheath will now be 
described. FIG. 3 shows, from left to right, a hemostasis device 50 
slidably connected to a balloon catheter 42, a tear-away insertion sheath 
30, an IAB bladder 40, and a femoral common artery 10. As shown in FIG. 3, 
an IAB device is inserted into the femoral common artery 10 through skin 
20 using the percutaneous Seldinger technique. Prior to insertion, bladder 
40 is wrapped about itself to reduce its diameter. The balloon catheter 42 
may be attached at its proximal end to a wrap handle (not shown) and may 
also be connected to an intra-aortic balloon pumping/monitoring system 
(also not shown). 
Next, a tear-away insertion sheath 30 is inserted into artery 10 through 
opening 14. The tear-away insertion sheath 30 may have a tear line 32 
which permits sheath 30 to be torn therealong and removed from insertion 
site 8 once the balloon 40 has been inserted into the aorta. 
Alternatively, insertion sheath 30 may be formed by linear extrusion (as 
is known in the art) to facilitate tearing thereof for removal purposes. 
After placement of tear-away insertion sheath 30, an intra-aortic balloon 
40 is passed through the insertion sheath and into artery 10 using the 
following percutaneous insertion (Seldinger) technique. First, a small 
hypodermic needle (not shown) is inserted through the skin 20 of a patient 
to perforate or puncture the artery 10. When blood spurts from the open 
external end of the needle, placement of the hypodermic needle within 
artery 10 is confirmed. A guide wire (also not shown) is fed into the 
artery 10 by passing the guide wire through the center of the hollow 
hypodermic needle. The hypodermic needle is then removed leaving the wire 
in place. 
Next, a dilator (also not shown) is placed over the guide wire and advanced 
through the perforated skin 20 and into artery 10 in order to dilate (that 
is enlarge) the artery 10 and create opening 14. The dilator is then 
removed and a series of larger dilators (not shown) are then fed over the 
guide wire and into artery 10 to continue the dilation procedure. Once the 
artery 10 has been fully dilated, the insertion sheath 30 is inserted 
through the opening 14 and into the artery and the last dilator is removed 
leaving the insertion sheath 30 extending through the opening 14 and 
available for insertion of the IAB device over the guide wire and into the 
patient without requiring surgery. 
Once the balloon bladder is inserted into the femoral artery and up into 
the aorta, the tear-away insertion sheath 30 is removed. Upon removal of 
the insertion sheath, however, the wall of the femoral artery may not 
completely constrict around the balloon catheter 42 resulting in 
uncontrolled bleeding at the insertion site. In order to control such 
bleeding, the hemostasis device 50 is slid down the balloon catheter 42 
towards insertion site 8 and partially into the opening 14. 
As discussed above, hemostasis device 50 is inserted into the opening 14 in 
the wall of artery 10 until the outside diameter of segment 50b fills 
opening 14 (see FIG. 5). In this position, elastic sealing contact is 
provided between the patient's skin opening and segment 50b, thereby 
preventing bleeding at the insertion site without restricting good blood 
flow through the artery 10 to any great degree. Any residual backflow of 
blood up through hemostasis device 50 during the insertion thereof will be 
prevented from spurting out of the hemostasis device 50 via cuff member 
60. 
It will be appreciated by those skilled in the art that the present 
invention in its broader aspects is not limited to the particular 
embodiments shown and described herein, and that variations may be made 
which are within the scope of the accompanying claims without departing 
from the principle of the invention and without sacrificing its chief 
advantages.