Angioplasty perfusion pump

A double acting piston blood pump having distal and proximal manifolds that are connected by a cylinder having a piston reciprocating therein and dividing the cylinder into a proximal and distal chambers. The manifolds have chambers that are in fluid communication with the distal and proximal chambers of the cylinder and one way valves for controlling fluid flow from and to the cylinder chambers.

BACKGROUND OF THE INVENTION 
The field of the this invention is to perfusion pumps for use in 
angioplasty procedures. 
Peristaltic pumps, used for pumping blood during open-heart surgery, do not 
have the capacity to generate pressures that are sufficient to force human 
blood through the relatively small lumens that are available in 
angioplasty balloon catheters. 
U.S. Pat. No. 5,066,282 discloses a Positive Displacement Piston Driven 
Blood Pump for use during angioplasty. The invention of this patent is a 
single acting pump that includes an accumulation chamber having a membrane 
that functions to smooth out the pulsations of the single acting pump. The 
accumulation chamber must be filled with liquid and thus increases the 
total volume of fluid that is required to fill the system which adds to 
the weight and size of the pump. In addition to the pump a driver 
component is required and when combined this complex pump unit is 
relatively large and cumbersome and inconvenient for use in an operating 
room environment. In the preparation of a heart pump for use any air in 
the internal cavity of the pump must be removed to eliminate the 
possibility of pumping air into the patients blood stream. This 
preparation process becomes more difficult and time consuming as the 
volume of the internal cavity of the pump increases. In column 4, lines 
9-14 of this patent, a double-acting arrangement is mentioned however such 
an arrangement is not described in full, clear and exact terms. 
Because blood pumps are in direct contact with blood, in order to avoid 
spreading disease they cannot be reused and thus must be disposal. For 
this reason it is important that the cost of heart pumps be kept to a 
minimum. 
Hemolysis, the breakdown of red blood cells, occurs normally when red blood 
cells lose their elasticity at the end of their life span. However, 
hemolysis may occur under many other circumstances such as when the blood 
is exposed to excessive shearing action as the result of greater than 
normal blood pressures, confining the blood flow to very small lumens and 
thus forcing the blood to flow at excessive flow rates and causing the 
blood to abruptly change its flow direction. Some hemolysis occurs when 
blood is forced to flow through the very small lumens available in an 
angioplasty catheter. The objective of this invention is to provide a 
simple blood perfusion pump, that can be manually powered with a minimum 
of effort, and can pump blood through an angioplasty catheter and balloon 
while minimizing hemolysis. In order to minimize hemolysis in the pump the 
conduits within the pump must be smooth, relatively large and shaped to 
accommodate directional changes in the blood flow path to thereby insure 
laminar flow and minimize turbulence and shear forces acting on the blood. 
SUMMARY OF THE INVENTION 
The present invention is directed to an apparatus that satisfies the need 
to provide a simple inexpensive blood perfusion pump, that can be manually 
powered with a minimum of effort, and can pump blood to an angioplasty 
catheter and balloon while minimizing hemolysis. 
According to the invention a double acting piston blood pump having a 
barrel with proximal and distal ends is provided. A piston slidable in the 
barrel divides the barrel into distal and proximal chambers. The piston 
has a rod connected thereto, that extends out the proximal end of the 
barrel for reciprocating the piston. Distal and proximal manifolds are 
secured respectively to the distal and proximal ends of said barrel. The 
manifolds have chambers that are in fluid communication with the distal 
and proximal chambers of the barrel. Input and output conduits are formed 
in each of said manifolds that are in fluid communication with the 
chambers. One way valves are provided in the input conduits that will 
permit fluid flow into the chambers and prevent fluid flow out of the 
chambers. One way valves are provided in the output conduits that will 
permit fluid flow out of the chambers and prevent fluid flow into the 
chambers. Input and output ports are formed in the distal manifold for 
receiving and discharging blood. A conduit extends from the distal 
manifold to the proximal manifold for providing fluid communication from 
the blood inlet port of the distal manifold to the inlet of the proximal 
input conduit. A second conduit extends from the distal manifold to the 
proximal manifold for providing fluid communication from the blood outlet 
port of the distal manifold to the outlet of the proximal output conduit. 
A conduit is formed in the distal manifold for providing fluid 
communication between the blood input port and the inlet of the distal 
input conduit. A conduit in provided in the distal manifold providing 
fluid communication between the blood output port and the outlet of the 
distal output conduit. 
To minimize hemolysis, when possible the conduits are in the form of round 
lumens having relatively large diameters, in the range of 0.032 to 0.250 
of an inch. Conduits having a diameter of 0.090 of an inch are preferable. 
The proximal and distal manifold are fabricated of four molded components 
that are assembled and then secured together by bonding or other fastening 
means. It is contemplated that the molded components could be fabricated 
with self locking and sealing features that would enable the components to 
be snapped together. As a result of assembling the manifolds from four 
components the internal chambers, conduits and valve seats can be made to 
precision and thereby avoid cavitation within the manifold. The one way 
ball valves included in the manifolds require that the ball be retained 
within a cage internally of the manifold. The fabrication of the manifolds 
from four components facilities the inclusion of one way valves in the 
manifolds. Of the four components that make up each manifold, three are 
identical and can be used in both manifolds. This of course greatly 
reduces the capital expenditure for molds and thus the cost of the 
perfusion pump. 
During the priming process it is contemplated that the pump, pump cavities 
and tubing will be filled with saline solution. The pump will then be 
disconnected from the source of saline solution and connected to the 
patients blood supply. Upon actuation of the pump the saline solution 
contained in the pump cavities can be pumped into the patient. Although a 
small amount of saline solution is not harmful to the patient it is 
desirable to minimized the amount of saline fluid that is pumped into a 
patient. For this reason it is important to minimize the fluid capacity of 
the pump. For example a pump that does not require an accumulation chamber 
is preferable over one that does because it will require less liquid to 
fill it. 
The pump of this invention has a stroke capacity in the range of 0.5 to 6.0 
cubic centimeters per stroke, the preferred capacity is about 3 cubic 
centimeters per stroke. This capacity can be accomplished with a piston 
diameter in the range of 0.100 to 0.600 of an inch with a preferred 
diameter of 0.187 of an inch and a stroke length in the range of 2-12 
inches and a preferred stroke of approximately 6 inches. The piston rod 
should have a diameter in the range of 0.060 to 0.125 and a preferred 
diameter of 0.090 inches. A pump having these limitations will be light 
and can be easily, confidently and comfortably handled by an operator for 
extended periods without expending unusual physical strength. A perfusion 
pump as disclosed herein has been found to require a force to be exerted 
on the handle in the range of 2 to 10 pounds. With the application of such 
a force the perfusion pump has developed pressures in excess of 250 pounds 
per square inch.

DETAILED DESCRIPTION OF THE INVENTION 
FIG. 1 discloses the perfusion pump 10 connected to an catheter manifold 
assembly 12. In this illustration some of the internal cavities and 
conduits and of the distal manifold 14, proximal manifold 16 and the 
piston 24 are shown as they may be seen if the components of the perfusion 
pump 10 were made of a clear plastic material. Also, lines with arrows 
have been included in FIG. 1 to trace the pathways that blood follows 
through the pump. 
In the following discussion of FIG. 1 the check valves within the proximal 
and distal manifolds will not be mentioned since they are not seen in this 
illustration. The check valves will be fully discussed subsequently. Blood 
enters the perfusion pump 10 through the swivel luer 34 and travels 
through inlet tube 30 to the distal manifold 14. Blood flowing into distal 
manifold 14 can follow either pathway A or pathway B. When blood follows 
pathway A it leaves distal manifold 14 and flows through upper tubing 18 
to the proximal manifold 16. When the piston 24 is moved in the distal 
direction blood following pathway A flows from the proximal manifold 16 
into the proximal end of barrel or cylinder 22. When the piston 24 is 
moved in the proximal direction, by pulling on handle 28, flow is reversed 
and blood flows out the proximal end of barrel or cylinder 22 into the 
proximal manifold 16 and then into the upper tubing 20 which leads into 
distal manifold 14. This stream of blood then flows out of distal manifold 
14 into outlet tube 32 and swivel luer 36. 
The inlet and outlet tubes 32 and 34 should be made from compliant material 
such as reinforced vinyl hose. It is important that tubes 32 and 34 be 
made from a material that will permit a small amount of expansion and 
contraction corresponding to the pulsation of the pump. This expansion and 
contraction functions to smooth out the peaks and valleys in the pulses. 
The above discussed movement of piston 24 in the proximal direction also 
created a pathway B flow of blood from inlet tube 30 into and through 
distal manifold 14 and then into the distal end of barrel or cylinder 22. 
When piston 24 is forced to move distally, by actuation of the handle 28, 
blood is forced out of the distal end of barrel or cylinder 22 into distal 
manifold 14 and then through outlet tube 32. In some situations a 
thrombosis filter or a bubble trap or both could be inserted in outlet 
tube 32 to insure that thrombosis or air is not pumped into the patient. 
The balloon catheter 13 is of the type that has a guide wire lumen that 
extends its entire length. Reference may be made to the U.S. Patent to 
Solar et al, U.S. Pat. No. 4,976,690 for a detailed disclosure of a 
balloon catheter of this type. When the angioplasty balloon is located 
over the stenoses the guide wire can be removed and the guide wire lumen 
can then be used to pump blood through the balloon into the vessel beyond 
the stenoses. The balloon catheter 13 extends through the mainport 40 of a 
Y-adapter 38 and out its distal end. A guide catheter 44 is connected to 
the distal end of the Y-adapter 38 and is inserted percutaneously into the 
patients vessel. The inside diameter of the guide catheter 44 is larger 
than the outside diameter of the balloon catheter's outer shaft 46, thus 
forming a coaxial lumen therebetween. The distal end of the guide catheter 
44 is open and blood from the patients can flow in the proximal direction 
through the coaxial lumen. This blood flow from the patient flows into the 
Y-adapter 38 and out its sideport 42. Swivel luer 34 and inlet tube 30 are 
connected to sideport 42 and the blood stream from the patient thus flows 
through the Y-adapter 38 into the perfusion pump 10. As the patients blood 
flows through the perfusion pump 10 its pressure is increased and it exits 
the perfusion pump 10 at a sufficiently elevated pressure to flow through 
the small guide wire lumen of the balloon catheter 12. 
FIG. 2 is an exploded view of the perfusion pump 10 showing the component 
parts separated from each other along the longitudinal axis of the pump. 
In this view internal chambers and conduits of the component parts are 
visible and their structure and function will be made clear in the 
following discussion. 
When the perfusion pump 10 is assembled the distal splitter manifold 50, 
distal intermediate manifold 52, distal check manifold 54 and distal 
Y-manifold 56 are nested together and secured to each other by bonding or 
other connecting means. It should be noted that since pressurized fluid 
will be flowing through the cavities formed by this assembly of components 
the connection between the components must act to seal fluid flow between 
the components. It is also important that air not be permitted to enter 
the cavities in the perfusion pump 10 between the components. Although, 
not illustrated it is contemplated that self locking connecting means 
could be molded into the component parts such that they could snap 
together in the assembly process. The above remarks regarding the assembly 
of the distal component parts that make up distal manifold 14 apply 
equally to the proximal end manifold 58, proximal intermediate manifold 
60, proximal check manifold 62 and proximal Y-manifold 64 of the proximal 
manifold 16. The component parts should be molded from a light strong 
material such as polycarbonate. 
The piston 24 has a groove cut in its outer cylindrical surface for receipt 
of an o-ring 66. The o-ring 66 provides a liquid seal between the piston 
24 and the inner wall of the barrel or cylinder 22 so that when the piston 
24 reciprocates in barrel or cylinder 22 fluid will not flow past piston 
24. 
It should be understood that distal intermediate manifold 52 and proximal 
intermediate manifold 60 are identical but face in opposite directions. As 
a result both ends of this identical component can be seen in FIG. 2. 
Referring first to the end of this component that is seen when looking at 
distal intermediate manifold 52. There are a pair of tubing seats 70 and 
72 that extend partially through the component. At the base of these 
tubing seats there are smaller diameter openings (not seen) that extend 
through the remainder of the component. In the lower half of the component 
there is an oval shaped opening 74 that extends partially through the 
component. There are a pair of small diameter openings 75 that extend from 
the bottom of the oval shaped opening 74 through the remainder of the 
component. On the end seen when viewing proximal intermediate manifold 60 
a pair of downwardly diverging grooves 76 and 78 are seen. These grooves 
76 and 78 have a semicircular cross section. The upper small diameter 
openings that open into tubing seats 70 and 72 also open into the upper 
ends of grooves 76 and 78 and the lower small diameter openings 75 open 
into the lower ends of grooves 76 and 78. The distal ends of upper tubing 
18 and 20 are received in the tubing seats 70 and 72 of distal 
intermediate manifold 52. The proximal ends of upper tubing 18 and 20 are 
received in the tubing seats 70 and 72 of proximal intermediate manifold 
60. The upper tubing 18 and 20 should be made from material such as 
acrylic tubing. 
The distal check manifold 54 and proximal check manifold 62 are also 
identical and since they are turned to face each other both end faces are 
visible in FIG. 2. The end face of distal check manifold 54 seen in FIG. 2 
has an oval shaped opening 80 formed therein. Two check valve conduits 82 
and 84, visible when viewing proximal intermediate manifold 60, extend 
from the bottom of oval shaped opening 80 through the remainder of the 
component. On the face seen when viewing proximal check manifold 62 there 
is an oval shaped extension 86. The check valve conduits 82 and 84 can be 
seen in the face of extension 86. It should be noted that oval shaped 
extensions 86 are received in the oval shaped openings 74 formed in distal 
intermediate manifold 52 and proximal intermediate manifold 60. 
The distal Y-manifold 56 and proximal Y-manifold 64 are identical and thus 
both faces of this component are visible in FIG. 2. In the visible face of 
distal Y-manifold 56 there is a cylinder seat 88. In the face of proximal 
Y-manifold 64 that is seen there is an oval shaped extension 90 that has a 
slot 92 formed therein. Both ends of slot 92 communicate with cylinder 
seat 88. 
The proximal and distal ends of the barrel or cylinder 22 are received in 
the cylinder seats 88. Thus the distal manifold 14 and proximal manifold 
16 are connected by barrel or cylinder 22 and upper tubing 20 and 22. 
The distal splitter manifold 50 and proximal end manifold 58 are similar 
but not identical. In the visible face of distal splitter manifold 50 
there is a pair of downwardly diverging groves 94 and 96, that have 
semicircular cross sections. Identical groves 94 and 96 are formed in the 
face of proximal end manifold 58 that is not visible in FIG. 2. Groves 94 
and 96 mate with groves 76 and 78 formed in distal intermediate manifold 
52 and proximal intermediate manifold 60 such that together they form 
conduits having circular cross sections. In the face of distal splitter 
manifold 50 that is not visible there are connectors for inlet tube 30 and 
outlet tube 32. These connectors are aligned with the upper ends of 
grooves 94 and 96. In the visible face of proximal end manifold 58 there 
is an opening 98 from which the rod 26 extends. The opening 98 is larger 
in diameter than rod 26 and the back ring 48 is received in this space. 
The back ring 48 functions to provide a seal for the reciprocating rod 26. 
FIG. 3 is a cross sectional view of the perfusion pump 10 taken along lines 
3--3 of FIG. 1. This cross sectional view cuts through the valve conduits 
82 and 84 that are formed in distal check manifold 54 and proximal check 
manifold 62. As can be seen in FIG. 3 the check valve conduit 84 of distal 
check manifold 54 functions as an input check valve. The input valve seat 
102 is opened and closed by the ball valve 104. As can be seen in this 
view a portion of distal Y-manifold 56 cooperates with the valve seat 102 
to form a cage that retains the ball valve 104. 
The check valve conduit 82 of distal check manifold 54 functions as an 
output valve having a output valve seat 110 and a ball valve 112. A 
portion of the oval shaped opening 74 formed in distal intermediate 
manifold 52 cooperates with valve seat 110 to form a cage for retaining 
the ball valve 112. 
The check valve conduit 82 in proximal check manifold 62 functions as an 
inlet valve having a input valve seat 106 and a ball valve 108. A portion 
of proximal Y-manifold 64 cooperates with the input valve seat 106 to form 
a cage for retaining the ball valve 108. 
The check valve conduit 84 in proximal check manifold 62 functions as an 
outlet valve having a output valve seat 114 and a ball valve 116. The 
bottom of the oval shaped opening 74 formed in proximal intermediate 
manifold 60 cooperates with output valve seat 114 to form a cage to retain 
ball valve 116. 
The piston 24 and connected rod 26 are also visible in this view. The 
o-ring 66 that is carried in a grove formed in the cylindrical surface of 
piston 24 provides a seal for piston 24 to prevent fluid flow past the 
piston 24. At the proximal end of the rod 26 the back ring 48 and an 
o-ring 100 function to seal the rod 26 to prevent liquid leakage at this 
point. 
The following discussion of operation of perfusion pump 10 should be read 
with reference to FIGS. 1-3 and will be more specific than the earlier, 
especially with respect to the discussion of the one way check valves. 
Blood enters the perfusion pump 10 through the swivel luer 34 and travels 
through inlet tube 30 to the distal manifold 14. Blood flowing into distal 
manifold 14 can follow either pathway A or pathway B. When blood follows 
pathway A it leaves distal manifold 14 and flows through upper tubing 18 
to the proximal manifold 16. The fluid flows down the conduit formed by 
groves 76 and 96. The flow then enters inlet check valve conduit 82, 
forces ball valve 108 off valve seat 106, and into a chamber 120 formed in 
proximal Y-manifold 64. When the piston 24 is moved in the distal 
direction blood following pathway A flows from chamber 120 into the 
proximal end of barrel or cylinder 22. When the piston 24 is moved in the 
proximal direction, by pulling on handle 28, flow is reversed and blood 
flows out the proximal end of barrel or cylinder 22 into chamber 120 and 
then into output check valve conduit 84 where it forces ball valve 116 off 
valve seat 114. The fluid then flows up the conduit formed by channels 94 
and 78 and then into upper tubing 20 which leads into distal manifold 14. 
This stream of blood then flows through the conduit in distal 
intermediated manifold 52 and distal splitter manifold 50 into the outlet 
tube 32. 
The movement of piston 24 in the proximal direction also created a pathway 
B flow of blood from inlet tube 30 down the conduit formed by groves 94 
and 78 into the inlet conduit 84 where it forces ball valve 104 off valve 
seat 102 and then into chamber 122 which is formed in distal Y-manifold 
56. The fluid then flows from chamber 122 into the distal end of barrel or 
cylinder 22. 
When piston 24 is forced to move distally, by actuation of the handle 28, 
blood is forced out of the distal end of barrel or cylinder 22 into 
chamber 122, up the conduit formed by grooves 96 and 76 and then out 
through outlet tube 32. 
The one way check valves, illustrated in FIG. 3, are all of the type in 
which a ball valve is restrained in a cage having a valve seat. When there 
is fluid flow through the cage toward the valve seat the ball valve seats 
on the valve seat and flow through the cage is stopped. When flow is in 
the opposite direction it forces the ball valve off the valve seat and 
permits fluid flow through the cage. In FIG. 3 there is no structural 
means, such as a spring, exerting a pressure on the ball valve in the 
direction toward the valve seat. Thus in this embodiment, when there is no 
flow through the cage, there is no assurance that the ball valve is 
resting on the valve seat. 
In FIGS. 4 and 5 another embodiment of a one way valve is illustrated. This 
embodiment represents the preferred embodiment. FIG. 4, is a cross section 
view through the element forming the valve conduit 130 and the valve seat 
132. The ball valve 134, which is not shown in cross section, includes a 
T-shaped restrainer comprising a stem 136 and a cross bar 138. The stem 
136 is dimensioned such that at equilibrium the ball valve 136 is resting 
on valve seat 132 and is restrained from movement away therefrom. This one 
way check valve is designed such that when there is no flow through the 
valve conduit 130 there is a pre-load force on ball valve 134. This 
pre-load force should be in the range of 1-100 grams and preferable about 
5 grams. The ball valve 136 with its integral T-shaped restrainer is 
installed by pinching the free ends of cross bar 138 together such that 
they can pass through the restricted portion of valve conduit 130. The 
cross bar will spring back into its original shape, as seen in FIG. 4, 
after it is in place. The inlet side of the conduit 130 is flared at 140 
to provide a large entrance into the conduit 130. The cross bar 138 
extends across the flared inlet opening into conduit 130 and is seated on 
a flat surface 142. When there is fluid flow in the direction of the 
arrows in FIG. 4, the cross bar 138 bows up into the flared opening 140 of 
the inlet conduit thus permitting ball valve 134 to moved off valve seat 
132 and allow flow through the one way valve. FIG. 5 is a bottom view of 
FIG. 4 and it illustrates the relationships between the components of this 
one way valve. 
FIG. 6 illustrates another embodiment of one way valve that could be used 
in the perfusion pump. In this embodiment there is a spring 150, that 
could be stamped from sheet material, in engagement with the ball valve 
152. Spring 150 exerts a pre-load force on ball valve 152 causing it to 
set on valve seat 154. When this pre-load force is overcome the one way 
valve opens and fluid flows past the ball valve 152. It is noted that this 
embodiment requires a reaction surface 156 for spring 150. The spring 150 
of this embodiment has a pair of cantilever tabs that are permanently bent 
in the direction toward the ball valve. The spring 150 bears against 
reaction surface 156 and the free ends of the cantilevered tabs contact 
the ball valve 152. 
FIG. 7 illustrates still another embodiment of a one way valve that could 
be used in the perfusion pump. In this embodiment there is a coil spring 
160 in engagement with the ball valve 162 forcing it into contact with the 
valve seat 164. In this embodiment one end of coil spring 160 engages a 
reaction surface 166 and the other end engages ball valve 160. This causes 
a pre-load force to be exerted on ball valve in the direction of valve 
seat 164. 
Although the illustrations of check valves included in this application all 
have spherical shaped valves it should be understood that the valve could 
have an ellipsoid, oval or other similar shape. Also it should be 
understood that other common types of one way valves such a rubber flap 
valve could be used as well as a ball type valve. 
Although the present invention has been described in terms of specific 
embodiments, it is anticipated that alterations and modifications thereof 
will no doubt become apparent to those skilled in the art. It is therefore 
intended that the following claims be interpreted as covering all such 
alterations and modifications as fall within the true spirit and scope of 
the invention.