JPH04156856A - Pump for circulatory assistance - Google Patents

Abstract

PURPOSE: To provide a circulating auxiliary pump for temporary use by providing a slender cylindrical housing, a pump device arranged in it and a driving device arranged outside a blood vessel connected to the pump device through a driving shaft, and inserting its housing up to the inside of a heart by inserting it into a blood vessel of a person. CONSTITUTION: Blood from the left ventricle 10 is sucked in through an inflow end part 32, and is forcibly sent through a discharge nozzle 46 by rotation of a rotor 42, and is pressurized, and is injected into a venturi tube 48. Therefore, a reduced pressure condition is generated in an annular space 52 around a discharge end part 49 of the discharge nozzle 46, and the blood gathered in a chamber 56 opening in the left ventricle 10 is sucked in the venturi tube 48 through an inflow end part 50, and is mixed with a blood flow discharged through the discharge nozzle 46. Since the outflow end part cross-sectional area of the venturi tube 48 increases, blood pressure in its outflow end part reduces, and becomes equal to inflow pressure in the inflow end part 32 of a blood pump 14. The blood is discharged in the aorta 24 through an outflow port 58 formed in a discharge end part 34 of the blood pump 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a blood pump. More particularly, the invention relates to a circulation assist pump for temporary use. This pump connects the patient's vascular system (VA+CULA+
It is inserted into the heart (Bslem) and used to provide temporary circulatory support to the left or right ventricle of an infarcted heart.

[Conventional technology]

Death and disability due to heart disease are generally caused by malfunctions in the pumping function of the infarcted left ventricle or right ventricle. The heart of a patient in this condition otherwise functions normally, except that it does not provide sufficient blood flow needed to keep the patient alive. Typically, patients with these conditions require major surgery to maintain the heart and provide adequate blood flow.

-Other areas where temporary circulatory support is required are allograft cardiac replacement (xlloHxN ca + diacrepla
cement) and heart transplantation. Although the one-year survival rate after heart transplantation has now reached 80%, many patients die while waiting for a transplant. Similarly, as many as 20% of people who could have survived had they been given circulatory support while immune suppressants were used to combat rejection of their transplanted hearts, have died. There is a great need for effective circulatory support pumps to perform transplants and sustain patient life until the allograft stabilizes. As the average expected lifespan in the United States continues to increase, coronary artery disease and chronic congestive heart disease are expected to increase the use of mechanical circulatory support. A practical estimate of the number of potential candidates for mechanical circulatory support would be 3Do, 000 patients each year in the United States.

Methods and devices for circulatory support of the heart are conventional. US Pat. No. 4,625,712 discloses a high performance intravascular blood pump. The pump is inserted into the heart via the femoral artery and is powered via a flexible cable derived from an external power source. The drive cable is housed within a catheter attached to the pump. The pump is 10, (10 [1 rpm to 20. O
Hrpm and generates blood flow on the order of about 4 liters per minute.

US Pat. No. 3,505,987 discloses a counterpulsation system for coronary artery relief. This system has an expandable impeller placed within the patient's aorta. At the same time as the impeller expands and contracts, it reciprocates within the aorta and synchronizes with the pumping action of the heart, lowering blood pressure in the aorta when the heart contracts, and increasing blood pressure in the aorta when the heart dilates. do.

U.S. Pat. No. 3,667,069 discloses an implantable jet pump for right ventricular replacement or supplementation. This jet pump has an elongated tubular structure and is equipped with an upstream drive nozzle. From this drive nozzle, the pressurized aortic blood flow is discharged into the suction nozzle, creating a reduced pressure condition. As a result, venous blood is drawn into the driving stream, mixed, and distributed to the pulmonary circulation. The jet pump is in the left ventricle (leN heart)
Alternatively, it may be powered by blood pumped from a prosthetic device that replaces the left ventricle.

US Pat. No. 4,051,840 discloses an aortic segment that is surgically implanted into the thoracic aorta.

The aortic segment expands and contracts in a regular manner, creating pressure waves in the bloodstream. The pressure waves generated strengthen blood circulation to the human body and help the heart.

Generally, available methods of cardiac circulatory support require major surgery to implant the device, which represents a great risk to patient survival.

The device disclosed in US Pat. No. 4,625,712 is inserted into the heart via the femoral artery. Therefore, since major surgery is not performed, the risk to the patient is small. However, in order to generate accurate blood flow, the pump and drive shaft must be rotated at very high speeds through the bends and sharp curves of the femoral artery. Extreme care must be taken to avoid the formation of hot spots within the femoral artery. This is an easy-to-implant, low-risk temporary therapy that provides enough blood flow to help the heart and allow it to heal or keep the patient alive while awaiting a transplant. Circulation auxiliary pumps for general use have not heretofore been provided.

[Summary of the invention]

This invention relates to a small, temporary circulatory support pump that is inserted into a patient's heart to provide circulatory assistance. The pump is placed into the left ventricle of the heart by a catheter threaded through the patient's aortic system. The pump utilizes an ωoineaυ type pump principle and is capable of pumping large volumes of blood at relatively low speeds and pressures. In embodiments of the invention, the blood flow is pressurized to create a suction effect and increase the amount of blood pumped through the patient's circulatory system.
It uses a Venturi tube structure.

The features, advantages, and objects of the invention described above will become clearer from the embodiments of the invention described below with reference to the accompanying drawings.

〔Example〕

Embodiments of the circulation auxiliary pump according to the present invention will be described below based on the accompanying drawings. First, please refer to FIGS. 1 and 2. The blood pump of this invention is inserted into the left ventricle 10 of the heart 12. A blood pump is designated by the reference numeral 14 and is attached to the front end of catheter 16. In this example, access to the heart 12 is through the femoral artery 18. Although the femoral artery is the preferred insertion site, access to the heart 12 may be provided through other arteries or other surgical devices.

In the embodiment, blood pump 14 is located within left ventricle 10 . However, in some cases it may be preferable to locate blood pump 14 within right ventricle 20. right ventricle 20
Access can be provided via the pulmonary artery 22.

In operation, the inflow end of blood pump 14, shown in FIG. 1, is positioned within left ventricle 10. blood pump 14
The discharge or outflow end of is located within the aorta 24. Thus, a portion of blood pump 14 extends into left ventricle 10 via heart valve 26. Blood is pumped from the left ventricle 10 via the blood pump 14 into the aorta 24 in the direction of arrow 28.

In some patients, it may be undesirable to place blood pump 14 within left ventricle 10. In this case, a suction tube 15 is attached to the inflow end of the blood pump 14. Suction tube 15 is formed from a flexible elastomeric material and extends from the inlet end of blood pump 14 into left ventricle 10 of heart 12, as shown in FIG.

Next, a description will be given with reference to FIG. Blood pump 14 is depicted in more detail in this figure. Blood pump 14 is driven by a flexible drive shaft 30 extending through catheter 16 . As best seen in FIG. 2, drive shaft 30 is driven by a motor 31 located outside the patient's body. Blood pump 14 is fixed to the tip of catheter 16. blood pump 1
4 and catheter 16 are guided through the thigh and into the left ventricle 10. Once reaching the left ventricle 10, the blood pump 14 is placed within the left ventricle 10 of the heart. Utilizing well-known insertion techniques, blood pump 14 is positioned so that inlet end 32 extends through heart valve 26 and into left ventricle 10 . Outflow end 34 of blood pump 14 is positioned outside left ventricle 10 and pumps compressed blood into aorta 24, as shown in FIG.

In the embodiment of the invention shown in FIG. 3, blood pump 14 has an elongated body 36 having a generally cylindrical shape. The inlet end 32 of the body 36 has a cone-like shape. The front end of the inflow end 32 has a rounded tip.
Heart valves and heart tissue 1 Heart valves 2 without any damage
6 into the left ventricle 10.

The inflow end 32 has a number of inflow ports 38 to allow blood collected in the left ventricle 10 to flow freely into the blood pump 14. A stator 40 and a rotor 42 are housed within the main body 36. The stator and rotor operate using the Mwano pumping principle. The Mwano pumping principle utilizes a rotary motion that constantly moves a seal within the stator 40 to pump blood through the blood pump 14. The stator 40 is made of a resilient material, and the rotor 42 is made of helically molded stainless steel.

Rotor 42 is coupled to drive shaft 30 by a flexible coupling device 44 . flexible coupling device 44
is used, the rotor 42 is connected to the drive shaft 3
When driven by 0, the rotor 42 end is allowed to move in a helical path.

A discharge nozzle 46 is provided at the discharge end of the stator 40 to direct the pumped blood to an inflow end 50 of the Venturi tube 48.
is provided. As shown in the figure, the discharge nozzle 4
The outlet end of 6 extends into the inlet end 50 of venturi tube 48 . In this way, the discharge end 4 of the discharge nozzle 46
An annular space 52 is formed between the venturi tube 9 and the inlet end 50 of the venturi tube 48 . An inlet end 50 of the venturi tube 48 opens into a chamber 54 formed in the body 36 about the exhaust nozzle 46 and the venturi tube 48 . Blood collected within the left ventricle 10 is transferred to a plurality of ports 56.
into chamber 54 via.

In operation, in the embodiment of FIG. 3, blood from the left ventricle 10 is drawn through the inflow end 32 and pumped into the exhaust nozzle 46 by rotation of the rotor 42. When the blood is pumped through the discharge nozzle 46
The pressure is increased by restricting the discharge area of the venturi tube 48, which injects blood into the venturi tube 48. The restriction of the exhaust nozzle 46 and the venturi tube are designed such that blood pumped through the exhaust nozzle 46 reaches Venturi velocity. Venturi speed can be determined accurately. Once the venturi velocity is reached, a vacuum is created in the annular space 52 around the discharge end 49 of the discharge nozzle 46. Blood collected in the chamber 56 opening into the left ventricle 10 is thus drawn into the Venturi tube 48 via the inlet end 50 and into the outlet nozzle 46.
mixed with the blood stream exiting through the The outlet end of the Venturi tube has an outwardly tapered shape as shown in FIG. Therefore, the pressure downstream of the Venturi tube decreases because the cross-sectional area of the Venturi tube increases. The blood pressure at the outlet end of Venturi tube 48 decreases and becomes equal to the inlet pressure at the inlet end 32 of blood pump 14 .

In this way, more blood is pumped through the blood pump]4 at a lower pressure. For example, the blood pump 14 has a pressure of 3 ps i (0.21 kg/c) at its inlet end 32.
Il) Blood is transferred at 1 liter per minute. but,
When this blood flows through the discharge nozzle 46 into the Venturi tube 48, the pressure in the Venturi tube 48 is 9 p.
s i (0.63 kg/car) and a reduced pressure is created in the annular space 52 . This reduced pressure draws an additional 2 liters of blood from chamber 54 into the blood stream that is pumped into Venturi tube 48 . The pressure of the blood returns to 3 p s i (0,2] kg/Ci at the outlet end of the Venturi tube 48. By flowing the pumped blood into the Venturi tube 48, 3psi (0.21kg/cff
l) Blood pump 1 at a rate of 3 liters per minute
4 can be pumped. Blood is expelled into the aorta 24 through an outflow port 58 formed in the discharge end 34 of the blood pump 14.

Next, a description will be given with reference to FIG. A further embodiment of the blood pump according to the invention is designated by the reference numeral 60 in the figure. Blood pump 60 utilizes the same Mwano type principles to flow blood through the pump, but with some modifications to the stator and rotor, as will be explained in more detail below. Blood pump 60 is placed by catheter 16 into left ventricle 10 of heart 12 in the same manner as described above with respect to blood pump 14.

Blood pump 60 is very similar to blood pump 14. For this reason, like reference numbers are used to represent similar parts. However, the stator 62 of the blood pump 60 is provided with multiple suction inlet ports that drain into a common exhaust duct. The stator 62 is formed from a resilient material and has three inlet ports 64, 66 .
It has 68. Inlet port 64 is located at the front end of stator 62 . The inlet ports 66, 68 are connected to the stator 6
2 and is formed by drilling an oblique hole in the body of the stator 62 leading into the cavity of the rotor. Each of the inlet ports 64, 66, 68 is connected to a respective rotor cavity 7.
It communicates with 0.72.74. rotor cavity 70
, 72° and 74 form the rotor cavity of the blood pump 60. The rotor cavities 70, 72, 74 have outflow ports 76, 78, 74 that drain into a common exhaust duct 82.
It has 80. The rotor cavities 70° 72.74 are separated by shaft stabilizers 84. Shaft stabilizer 84 supports and seals around rotor 86 within the rotor cavity of blood pump 60. The rotor 86 is driven by a drive shaft 88 connected to the drive motor 31. Drive shaft 88 is coupled to rotor 86 by a flexible coupling 90. Therefore, when the rotor 86 is rotated by the drive shaft 88, the end of the rotor 86 can trace a slight trajectory.

The blood pump 60 shown in FIG. 4 has multiple stages of pumping performed by a single rotor and stator, with each rotation of the rotor 86 pumping more blood to the blood pump 60.
It is designed to be able to flow into the . rotor cavity 70
．． 72 and 74 are configured so that they can be pumped separately when the rotor 86 rotates. In operation, rotation of rotor 86 via drive shaft 88 causes continuous movement of the seal within each rotor cavity 70, 72, 74. As rotor 86 rotates, blood flows into rotor cavity 70, 72.74 through inflow ports 64, 66.68. Each rotation of the rotor 86 sweeps the rotor cavity 70.72.74, forcing blood through the outflow ports 76.78.80 into the common exhaust duct 82 and then into the conduit 92. Conduit 92 connects to aorta 2 via outflow port 93.
It is discharged into 4.

Next, a description will be given with reference to FIG. The figure shows a single-stage embodiment of a cardiac assist pump according to the invention.

Single stage blood pump 100 is substantially similar to multi-stage blood pump 60 shown in FIG. The pump is placed within the left ventricle 10 of the heart 12 in substantially the same manner as previously described.

Blood pump 100 has a stator 102 having a rotor 104 housed therein. The stator 102 is formed from a resilient material and is adapted to form a rotating seal within a helical stainless steel rotor 104. The stator 102 has a helical rotor cavity 101. Rotor cavity 101 has an inlet port 106 and an outlet port 108. Rotor 10
4 is connected to the drive shaft 110 by a flexible coupling device 112. The drive shaft 110 is fixed to the blood pump 100 by a shaft stabilizer 116.
centrally located within the exhaust conduit 114 of the.

In operation, single stage blood pump 100 has inlet port 1
Blood is drawn from the left ventricle 10 via 06. Rotor 1
As the 04 rotates, a movable seal is formed in the stator 102 and blood is pumped through the helical rotor cavity 101 and discharged into the exhaust conduit 114. Shaft stabilizer 116 has a plurality of openings 1 extending therethrough.
It has 18. Blood thus flows past the shaft stabilizer 116 and exits into the aorta 24 through an outflow port 120 located in the rear wall of the blood pump 100.

A cardiac assist pump according to the present invention utilizes the geometric relationship between a rotor and a stator to pump blood away from a patient's heart. When viewed in cross section, the rotor and stator are in contact with each other at two points forming two sealing lines along the length of the rotor and stator. The rotor has a single helical shape and is generally formed from a metallic material. The stator is a double helix (dou
blebelical) and generally made of elastomer. The interference fit (int++fe+encel, or compressive fit) between the rotor and stator creates a series of sealed chambers or cavities. The pumping action is performed by driving the rotor eccentrically within the stator. A liquid, such as blood, enters a cavity formed at the inlet end of the pump, travels through the cavity, and is expelled from the outlet end.

Since the sections of the rotor and stator that generate the force are smooth and curved, the surface area available for contact stresses is very small. In cross section, the stator is curved and the rotor has a circular cross section. Due to the different shapes of the rotor and stator, a wedge-shaped cavity is formed in the pump unit. As it rotates, the wedge-shaped cavity gradually moves. This allows the blood to find its way out without creating turbulence. Therefore, the volume of blood flowing through the pump of this invention is directly proportional to the speed of the rotor. Blood in a sealed cavity formed as the rotor rotates is transported axially from the suction or inlet end of the pump all the way to the outlet end.

Despite the fact that the rotor rotates, no turbulence occurs. Due to the constant volume of the closed cavity, there is no pressurizing force and therefore low surge (low 5u
A bombing effect of Be) is performed.

This low-surge pumping action can be applied to shear-sensitive materials (
ihear +ensive male+1ala
) is ideal for

The pump according to the invention is self-priming and non-cavity cheating.Prime causes suction movement of material that would otherwise not be moved. type of progressive cavity pump (p+og+essiye cav
itypump) is always in a self-priming state (in prime)
It is. However, the impeller pump loses priming and accelerates too much.

If you accelerate too much, air bubbles will form inside the pump, resulting in
A vacuum zone occurs in the bloodstream, causing separation of blood components. Blood, a non-Newtonian fluid, is susceptible to such spontaneous nonlinear viscoelastic behavior. In viscous fluid motion, each fluid element undergoes a sledy shearing motion. However, in nonlinear viscoelastic responses, simple flow symmetries are
Efficiency is reduced due to stress factors and turbulence. Simply put, the cardiac assist pump according to the invention does not generate pressurizing force, does not create turbulence in the blood in the confined cavity, and maintains a constant volume. The low surge action of the pumps disclosed herein generates an ideal flow consisting of (v++yp+edierable) = Neilton flow which is highly predictable.

The pump of the present invention is sized to produce a blood flow of 3 to 4 liters per minute, and yet has a blood flow of approximately 2.50 liters per minute.
It operates at a speed of 0 rpm and produces the blood necessary to sustain the patient's life while the patient's heart rests and provides treatment. The pump of this invention does not utilize propellers or turbine blades to pump blood. The Mwano type pump of the invention has a very low or no risk of hemolysis. Blood is pumped through the pump of the present invention by rotating the seal formed between the stator and the helical rotor as described above. Blood is thus forced through the stator with each revolution of the rotor. As the blood is pumped through the pump and discharged into the patient's aorta, no shear forces are created that would damage the blood cells.

The embodiments described above are merely illustrative and do not limit the invention. Therefore, the pump of this invention can be realized in any form without departing from the spirit and scope of the invention.

[Brief explanation of drawings]

The drawings show an embodiment of a pump according to the invention, FIG. 1 being a cross-sectional view of a human heart drawn to show the pump in a preferred location within the left ventricle of the heart; FIG. 3 is a partial cross-sectional view of the pump; FIG. 4 is a partial cross-sectional view of an alternative embodiment of the pump; and FIG. 5 is a partial cross-sectional view of a single stage pump. Partial Sectional View, FIG. 6 is a cross-sectional view of a human heart drawn to illustrate another embodiment of the pump. 14.60.100...Blood pump 15...Suction tube j6...Catheter 28...Arrow 30, 88.110...Drive shaft 31...Motor 32...Inflow end 34... -Outflow end 36...Main body 38, 64.66, 68.106-...Inflow hoard 40
, 62.102... Stator 42, 86.104... Rotor 44... Connection device 46... Discharge nozzle 48... Venturi pipe 49... Discharge end 50... Inflow end 52 ...Space 54...Chamber 56...Port 5B, 76, 78.80.93.108.120...
・Outflow port 70, 72.74...Rotor cavity 82...Exhaust duct 84.116...Shaft stabilizer 90...Connection member 92...Conduit 114...Exhaust conduit 118...Opening part Applicant Amerikan Bio; Tsu1゛・
Hidehiko Okada, Patent Attorney, Inc.
3 people outside) FIG, 7

Claims (1)

[Claims] 1. An elongated cylindrical housing; a pump device provided within the housing for pumping blood to help the patient's heart; and an extravascular device connected to the pump device. and a drive shaft connecting the pump device to the drive device, the housing having at least one inlet port and at least one outlet port, and the housing having at least one inlet port and at least one outlet port. The pump device has dimensions such that it can be inserted into a human blood vessel and into the heart, and the pump device has a stator and a rotor, and as the rotor moves on an orbit, a seal is continuously formed in the stator. movement for pumping blood therethrough, the housing having an ejection device for ejecting the blood into the patient's vasculature, the drive device driving the rotor and the drive shaft is connected to the rotor by a flexible coupling device, the rotor being configured to move in an orbit when the rotor is rotated by the drive device; Auxiliary pump. 2. A discharge nozzle is supported within the housing in alignment with the stator, the discharge nozzle having a restriction for pressurizing and ejecting blood pumped therethrough. Circulation auxiliary pump as described in section. 3. A venturi tube is disposed within the housing in alignment with the exhaust nozzle, and the venturi tube cooperates with the exhaust nozzle to form a reduced pressure region within the housing. Circulation auxiliary pump according to item 2. 4. the housing has a suction chamber formed around the exhaust nozzle and a portion of the Venturi tube;
4. The circulatory auxiliary pump of claim 3, wherein the suction chamber communicates with the reduced pressure region, and the suction chamber has at least one inlet port for allowing blood to flow into the suction chamber. 5. The blood collected in the suction chamber is forced through the Venturi tube by a suction force generated in a vacuum area around the discharge end of the discharge nozzle. The circulation auxiliary pump according to item 4. 6. The pumping device has at least two separate inlet ports communicating with separate rotor cavities formed in the pumping device, and the separate rotor cavities communicating with a common exhaust duct. A circulation auxiliary pump according to claim 1. 7. A circulation auxiliary pump according to claim 6, wherein said separate rotor cavities are separated by at least one shaft stabilizer supporting said rotor within said stator. 8. The pumping device has a stator made of an elastic material and a helical rotor made of stainless steel and disposed within the stator, and when the rotor rotates, the rotor moves through the stator. The circulation auxiliary pump according to claim 1, wherein the stator and the rotor cooperate to form a seal that moves continuously. 9. A suction tube is provided projecting forwardly from said cylindrical housing for insertion into the heart, said suction tube providing a passage for blood flow to said pump device. Circulation auxiliary pump as described in section. 10. The circulatory support pump according to claim 1, wherein the cylindrical housing equipped with the pump device is attached to the tip of a catheter, and the catheter is guided to the patient's heart.