PUMP CATHETER FOR THE DIRECTED PULSALITIAL CONDUCTION OF BLOOD

Description

Description of the invention

[0001] The present invention relates to a pump catheter for directed pulsatile conveyance of blood according to the preamble of claim 1.

[0002] Catheters of the type mentioned above are known as prior art, for example, from WO 2008 / 113785 A2, DE 10 2014 003 153 A1, DE 10 2014 012 850 A1, and US 5891012 A. Such catheters are preferably placed percutaneously – e.g., via an opening in the groin – in the human body using established catheter techniques for temporary cardiac and circulatory support in cases of acutely impaired cardiac function or heart failure. In particular, they can also be used in cases of severe aortic valve insufficiency. They serve to transport the body fluid to be conveyed from one location to another without significantly increasing the pressure of the fluid at the first location beyond the physiologically determined state, by implementing the principle of a submersible pump and preferably combining it with the principle of a diaphragm pump through the use of a balloon catheter.

[0003] A critical parameter for such catheters is the amount of blood that can be passed through the catheter per unit of time. This should be as high as possible while simultaneously minimizing the stress on the sensitive blood components.

[0004] The invention is therefore based on the objective of providing a catheter of the type mentioned above which has an improved design compared to previously known pump catheters.

[0005] This problem is solved by a catheter having the features specified in claim 1. Advantageous embodiments are specified in the dependent claims.

[0006] The invention provides that a proximal section and a distal section, comprising an expandable pump chamber and a hose section arranged distal to the pump chamber with an outlet opening, are present, and is characterized in that an inlet element with at least one inlet opening is arranged between the proximal section and the pump chamber, and the inlet element and the pump chamber are geometrically spaced apart from each other by a coupling element.

[0007] In the context of the invention, "distal" means "towards the end of the catheter inserted into the body." "Proximal" means "away from the distal end of the catheter." Thus, in the catheter according to the invention, a proximal end is arranged opposite the distal end and, when the catheter is inserted into the body as intended, typically protrudes from it.

[0008] The multi-part design of the catheter, with an inlet element spatially separated from the pump chamber, offers advantages in terms of fluid dynamics compared to currently known solutions. The shear forces that occur during the pulsatile propulsion of abnormally viscous fluids, such as human blood, are minimized by the design according to the invention, thus enabling a laminar and calm flow within the catheter. The coupling element arranged between the pump chamber and the inlet element is a flow-influencing factor.

[0009] Unlike previously known pump catheter concepts that provide inlet openings in the area of ​​the pump chamber, the geometric separation of the inlet openings from the pump chamber allows the inlet element to be designed independently of the pump chamber in an anatomically favorable manner, thus significantly improving blood uptake into the catheter compared to inlet openings that are distributed on the outer wall of the pump chamber.

[0010] The gentlest possible transport of blood is important. This invention minimizes current disadvantages of percutaneously placed temporary heart pumps, such as increased hemolysis rates and the associated tendency for platelet formation. Furthermore, friction losses are minimized. This offers advantages in terms of increased pulsatile pumping capacity.

[0011] The proximal section of the catheter serves to manipulate and correctly position the distal functional section within the patient. The proximal section is tubular in shape. Preferably, supply lines run through the lumen of the proximal section, communicating with structures of the distal section. The proximal section is sufficiently flexible to largely conform to the patient's anatomy during implantation, yet rigid enough to allow the distal section to advance to its destination within the patient.

[0012] The distal section, including the inlet element, acts as a blood pump and is designed to transfer blood from one location to another. Preferably, the catheter is intended to support the pumping function of the right heart. In this case, the catheter, distal section first, is advanced through an access point in the groin into the patient's body until it reaches its intended position within the right heart. In this position, the distal catheter section completely traverses the right heart. The inlet element with its inlet port and the pump chamber are intended to be positioned in the region of the inferior vena cava. (Inferior vena cava),The catheter should ideally lie in the direction of blood flow in front of the right ventricle. The section of tubing distal to the pump chamber should span the right ventricle, so that the outlet is ideally located in the region of the pulmonary artery. In this ideal position, blood can be drawn into the catheter via the inlet port in the region of the vena cava. Subsequently, the blood drawn into the catheter can be pumped distally (i.e., through the pump chamber and the distal section of tubing) to position the catheter in the region of the pulmonary artery (lung artery). Pulmonary aorta) to exit again via the distal outlet opening.

[0013] Within the pump chamber of the catheter, when configured for patient use, a fluid-fillable balloon is located. The displacement effect of the filled balloon enables directed blood flow through the catheter's interior in a distal direction. The balloon is supplied with fluid (usually a gas such as helium) from outside the catheter via a supply line that runs through the lumen of the proximal end of the catheter. The supply line terminates at or extends from the proximal end of the catheter. The supply line or the proximal end of the catheter can be connected to an (extracorporeal) pump unit. This pump unit can be controlled by an (integrated) control unit to periodically inflate the balloon with the fluid.The balloon and pressure hose unit can be formed by an intra-aortic balloon catheter (IAB catheter) known in the prior art, which is conventionally used in the so-called intra-aortic counterpulsation procedure. The pump unit can be formed by an IABP console (Intra-Aortic Balloon Pump) known in the prior art. Such a console is typically adjustable with respect to the frequency of the balloon inflation cycles with fluid and / or the volume of fluid per inflation cycle.

[0014] Preferably, the inlet element is expandable. For the purposes of the invention, the property "expandable" means that the inlet element is switchable between two configurations with different internal volumes. The configuration with the larger internal volume can be described as "expanded," and the other configuration can be described as "folded." In particular, the inlet element can comprise a self-expanding, i.e., self-erecting, stent.

[0015] A check valve may be arranged at the inlet opening and / or in the area of ​​the coupling section. The check valve may, in particular, be designed as a foil valve.

[0016] The inlet element can include a variety of inlet openings.

[0017] The coupling element can be configured to transfer at least a portion of the force acting on the distal segment during implantation and / or explantation of the catheter to the proximal segment. In particular, the inlet element and / or the pump chamber can form support structures that extend into the coupling element and mechanically stabilize it. Preferably, the support structures are extensions of the self-erecting stent and project into the coupling element in a web-like fashion. Preferably, the coupling element comprises coupling structures that engage the support structures of the inlet element and / or the pump chamber in a form-fit and / or force-fit manner, thereby at least partially transmitting the force. Preferably, the coupling structures are made of a non-metallic material, in particular a polymer.

[0018] Preferably, the geometric design of the inlet element in the expanded and folded configuration is adapted to an (individual) patient size.

[0019] The invention will now be explained in more detail with reference to the drawings. These show Fig. 1 a section of a pump catheter with an inlet element having multiple inlet openings and a coupling element, Fig. 2 a section of a pump catheter with an inlet element having multiple inlet openings and support structures extending into the coupling element, Fig. 3 a section of a pump catheter with an inlet element having multiple inlet openings and support structures extending into the coupling element, as well as coupling structures in the area of ​​the coupling element, and Fig. 4 a section of a pump catheter with an inlet element having multiple inlet openings and a coupling element that has a check valve.

[0020] Matching parts bear identical reference symbols in the different figures.

[0021] Fig. 1 Figure 1 shows a schematic representation of a section of a pump catheter 1 according to the invention. A tubular proximal section 2, which is connected to a Figure 1A distal section 3 adjoins the proximal section 1, which is only indicated. The distal section 3 comprises an inlet element 4 with several inlet openings 5, a coupling element 6, an expandable pump chamber 7, and a tube section 8 located distal to the pump chamber 7 with a distal outlet opening 9 at the distal catheter end 13. Like the proximal section 2, the tube section 8 is also only indicated for clarity. A balloon 10 is located inside the pump chamber 7 (dashed lines). A supply line 11 (also shown as a dashed line) is connected to the balloon 10, supplying it with helium and running inside the catheter 1 to the proximal catheter end 12. The catheter 1 can preferably be used as a right heart pump catheter.For application to the right heart, the catheter 1 is advanced into the patient's body via an opening in the body vein in the groin, with the distal end 13 leading the way, so that the distal tube segment 8 spans and thus bypasses the right heart. Ideally, the pump chamber 7 should be positioned in the region of the inferior vena cava, in the direction of blood flow, anterior to the right atrium of the heart. Alternatively, (partial) placement of the pump chamber 7 within the right atrium is possible. The supply line 11 is connected extracorporeally to a pump or pump console (not shown), which delivers alternating pulses at a predetermined frequency, e.g., approximately 100 bpm. (beats per minute)Helium is pumped into and then withdrawn from balloon 10. In this way, balloon 10 acts according to the displacement principle, driving the blood surrounding the catheter into the catheter 1 and distally through the catheter 1 to the outlet opening 9. The pump chamber 7, the coupling element 6, and the inlet element 4 are sufficiently rigid to withstand the suction or negative pressure effect of the deflated inner balloon 10. The inlet element 4 is spaced apart from the pump chamber 7 and has multiple inlet openings 5. The negative pressure generated inside the catheter by the deflated balloon 10 causes the blood surrounding the catheter 1 in the region of the inlet element 4 to be drawn through the inlet openings 5 ​​into the catheter interior and flow distally into the pump chamber 7.The inlet element 4 has a smaller outer diameter compared to the pump chamber 7, allowing venous blood to circulate freely between the vessel wall and the outer wall of the inlet element 4. This ensures that the inlet openings remain freely accessible during the suction phase and are not sealed off by the blood vessel wall. The coupling element 6 has an approximate length of 1 to 2 cm. This is sufficient to significantly reduce the blood flow towards the pump chamber. During the inflation phase of the balloon 10, the blood drawn into the catheter is displaced due to the pressure increase inside the catheter 1. To ensure optimal, directed displacement in a distal direction, a check valve 14 is located proximal to the pump chamber 7 (see figure). Fig. 4) is provided which closes as a result of the pressure increase and blocks the inlet openings, thus preventing backflow of blood from the inlet openings. In other embodiments, a check valve may also be provided at each individual inlet opening.

[0022] In the pump catheter according to the invention ( Fig. 2Support structures 16 are provided in the area of ​​the coupling element 6. These structures project into the coupling element 6 from the inlet element 4 and the pump chamber 7, thereby mechanically stabilizing the coupling element 6. The frame 15 for the inlet element 4 (as well as the frame 15 for the pump chamber 7) is preferably laser-cut from a sleeve made of a shape-memory alloy, for example, Nitinol. The geometric Z-structure of the frame 15, in conjunction with the shape-memory properties of the frame material, ensures that the frame 15 folds reliably, thus facilitating better handling during implantation and explantation of the catheter 1 into the patient's body.from the patient body against an installation pressure - for example by slipping a sleeve over it - can be reduced in diameter and on the other hand is sufficiently rigid in the installed state that the inlet element 4 and the pump chamber 7 do not collapse up to a predetermined maximum pressure difference between the internal pressure and the ambient pressure.

[0023] The outer surface of the frame 15 of the inlet element 4 is covered with a protective film. Inlet openings 5 ​​are formed in the protective film of the inlet element 4. In further embodiments, the inlet openings 5 ​​can be equipped with valves. For this purpose, some embodiments provide strips of film between the protective film and the frame 15. The film strips are approximately as wide as a single inlet opening 5 and are stretched between the protective film and the frame 15 such that the inlet openings 5 ​​are just covered. The film strips are connected to the protective film either at points or along lines perpendicular to the film strip. It is important that areas of the film strip are not connected to the protective film. In the event of overpressure inside the inlet element 4, the film strip is pressed against the protective film from the inside, thus blocking or sealing the inlet openings 5.Conversely, a negative pressure inside the inlet element 4 causes surrounding blood to be forced through the inlet openings 5 ​​against the foil strip. This results in the foil strip lifting inwards away from the outer film, thus releasing the barrier effect at the inlet openings 5. Because parts of the strip are not connected to the outer film, blood can flow into the interior of the inlet element 4 (see blood flow 18 at [reference]). Figures 3 , 4 ).

[0024] The coupling element 6, arranged between the inlet element 4 and the pump chamber 7, ensures a smoother flow of blood 18 in the distal direction, thus enabling a gentler overall transport of blood through the catheter 1. As already mentioned, the coupling element 6 is stiffened by means of the support structures 16. In some embodiments, the support structures 16 are webs, each formed on the self-erecting frame 15 (see Figure 1). Figures 2 , 3The external support structures 16 are covered with a protective film in the same way as the frame 15 of the inlet element 4. Like the inlet element 4, the coupling element 6 can also be "folded" or its diameter reduced by slipping a sleeve over it for optimized handling during catheter-based implantation and explantation. The coupling element 6 is advantageously between 5 and 20 mm long and has an inner diameter (in its erected state) between 5 and 15 mm.

[0025] In the exemplary embodiment of the Fig. 3 is a further development of the coupling element 6 of the catheter 1 of the Fig. 2 shown. The coupling element 6 of the Fig. 3The device also features coupling structures 17. These coupling structures 17 further improve the stiffening of the coupling element 6. The coupling structures 17 engage with the support structures 16. In some embodiments, the coupling structures 17 are thin rods. These rods can be made, for example, of a biocompatible plastic or a metal. If solid rods are used, they have bores at both ends into which the support structures 16 can be inserted, glued, or screwed. Hollow rods or sleeves function analogously. In this way, a positive-locking and / or force-locking connection is established, which further improves the handling of the catheter 1, particularly during implantation and explantation.

[0026] In the exemplary embodiment of the Fig. 4Finally, the coupling element 6 of the catheter 1 according to the invention additionally has a valve 14. The arrangement of the valve 14 improves the directed transport of blood in the distal direction: the valve 14 allows blood to pass in the direction of flow 18 and blocks the blood flow in the opposite direction. In the exemplary embodiment of the Fig. 4 The valve 14 is formed by a foil curtain 14, which is radially connected (glued, welded) to the outer film of the coupling element 6 and allows blood to pass in the direction 18, but not in the opposite direction. In addition, a grid (shown for clarity in [unclear]) can be located behind the curtain 14 in the direction of flow 18. Fig. 4(not shown) is positioned against which the curtain 14 is pressed when blood presses against the curtain 14 in the opposite direction 18. The grid can, for example, be formed by a perforated film which is also radially connected (glued, welded) to the covering film of the coupling element 6 behind the curtain. Reference symbol list

[0027] 1 Pump catheter 2 Proximal section 3 Distal section 4 Inlet element 5 Inlet port / 5' Inlet valve 6 Coupling element 7 Pump chamber 8 Distal tubing section 9 Outlet port 10 Balloon 11 Supply line 12 Proximal catheter end 13 Distal catheter end 14 Check valve 15 Self-erecting frame 16 Support structure 17 Coupling structure 18 Blood flow direction

Claims

1. Pump catheter (1) for the directed pulsatile conveying of blood, comprising: a proximal portion (2), a distal portion (3), the distal portion (3) comprising an expandable pump chamber (7) and a tube portion (8) which is arranged distally from the pump chamber (7) and has an outlet opening (9), an inlet element (4) which has at least one inlet opening (5) being arranged between the proximal portion (2) and the pump chamber (7), characterized in that the inlet element (4) and the pump chamber (7) are geometrically spaced apart from one another by a coupling element (6), the coupling element (6) being configured to transfer at least a portion of the force acting on the distal portion (3) during implantation and / or explantation of the catheter (1) into / from a patient's body to the proximal portion (2) in that the inlet element (4) and / or the pump chamber (7) form support structures (16) which extend into the coupling element (6) and mechanically stabilize it.

2. Pump catheter according to claim 1, characterized in that the inlet element (4) is expandable.

3. Pump catheter according to claim 1 or claim 2, characterized in that a check valve (14) is arranged at the inlet opening (5) and / or in the region of the coupling element (6).

4. Pump catheter according to any of the preceding claims, characterized in that the inlet element (4) comprises a plurality of inlet openings (5) or inlet valves (5').

5. Pump catheter according to claim 1, characterized in that the coupling element (6) comprises coupling structures (17) which engage form-fittingly and / or frictionally on the support structures (16) of the inlet element (4) and / or on the support structures (16) of the pump chamber (7) and effect at least a portion of the force transfer.

6. Pump catheter according to claim 5, characterized in that the coupling structures (17) comprise a non-metal material, preferably a polymer.