Patent Application
20230201561
This application is directed to pumps for mechanical circulatory support of a heart. In particular, this application is directed to a re-sealable member of a support structure for an impeller assembly that can be used in a catheter pump.
Heart disease is a major health problem that has a high mortality rate. Physicians increasingly use mechanical circulatory support systems for treating heart failure. The treatment of acute heart failure requires a device that can provide support to the patient quickly. Physicians desire treatment options that can be deployed quickly and minimally-invasively.
Intra-aortic balloon pumps (IABP) are currently the most common type of circulatory support devices for treating acute heart failure. IABPs are commonly used to treat heart failure, such as to stabilize a patient after cardiogenic shock, during treatment of acute myocardial infarction (MI) or decompensated heart failure, or to support a patient during high risk percutaneous coronary intervention (PCI). Circulatory support systems may be used alone or with pharmacological treatment.
In a conventional approach, an IABP is positioned in the aorta and actuated in a counterpulsation fashion to provide partial support to the circulatory system. More recently, minimally-invasive rotary blood pumps have been developed in an attempt to increase the level of potential support (i.e. higher flow). A rotary blood pump is typically inserted into the body and connected to the cardiovascular system, for example, to the left ventricle and the ascending aorta to assist the pumping function of the heart. Other known applications include pumping venous blood from the right ventricle to the pulmonary artery for support of the right side of the heart. An aim of acute circulatory support devices is to reduce the load on the heart muscle for a period of time, to stabilize the patient prior to heart transplant, or for continuing support.
There is a need for improved mechanical circulatory support devices for treating acute heart failure. Fixed cross-section ventricular assist devices designed to provide near full heart flow rate are either too large to be advanced percutaneously (e.g., through the femoral artery without a cutdown) or provide insufficient flow.
There is a need for a pump with improved performance and clinical outcomes. There is a need for a pump that can provide elevated flow rates with reduced risk of hemolysis and thrombosis. There is a need for a pump that can be inserted minimally-invasively and provide sufficient flow rates for various indications while reducing the risk of major adverse events. In one aspect, there is a need for a heart pump that can be placed minimally-invasively, for example, through a 15 FR or 12 FR incision. In one aspect, there is a need for a heart pump that can provide an average flow rate of 4 Lpm or more during operation, for example, at 62 mmHg of head pressure. While the flow rate of a rotary pump can be increased by rotating the impeller faster, higher rotational speeds are known to increase the risk of hemolysis, which can lead to adverse outcomes and in some cases death. Accordingly, in one aspect, there is a need for a pump that can provide sufficient flow while minimizing the likelihood of hemolysis at high rotational speeds. These and other problems are overcome by the inventions described herein.
Further, there is a need for providing an operative device of the pump capable of pumping blood at high flow rates while reducing the risk of hemolysis at the operative device. For example, when an impeller assembly is provided at the operative device, the high rate of rotation of the impeller may cause hemolysis, as blood flows past the high-speed impeller. Accordingly, there is a need for reducing the risk of hemolysis at the operative device of the pump, particularly when movable components are disposed at the operative device.
There is an urgent need for a pumping device that can be inserted percutaneously and also provide full cardiac rate flows of the left, right, or both the left and right sides of the heart when called for.
In one embodiment, a catheter pump is disclosed. The catheter pump can include an elongated catheter body having a distal portion including an expandable cannula having an inlet and an outlet. The expandable cannula can have a delivery profile and an operational profile larger than the delivery profile. An impeller assembly can include an impeller shaft and an impeller body, and the impeller body can include one or more blades. The impeller blades can draw blood into the expandable cannula when rotated. Further, an expandable support can have a mounting portion disposed on the impeller shaft distal of the impeller body to maintain a position of the impeller assembly relative to a cannula wall. The mounting portion can have a cylindrical member disposed on the impeller shaft and can include an enlarged distal portion having an inner diameter greater than the enlarged diameter at a distal end of the impeller shaft. Further, a re-sealable member can be disposed in the enlarged distal portion of the cylindrical member. The re-sealable member can have a path through the re-sealable member along a length dimension of the re-sealable member through which a guidewire can be positioned. The re-sealable member can reseal along the path through the re-sealable member when the guidewire is removed. In some embodiments, the re-sealable member can be a septum of varying shapes, with varying path lengths through the septum. In other embodiments, the re-sealable member can be a duckbill valve.
In another embodiment, an apparatus for inducing motion of a fluid relative to the apparatus is disclosed. The apparatus can comprise a motor. An elongated catheter body can be coupled with the motor. The elongated catheter body can include an expandable distal portion having an inlet and an outlet and a support structure disposed about a lumen. The expandable distal portion can have a delivery profile and an operational profile larger than the delivery profile. The apparatus can include an impeller comprising at least one impeller blade. The apparatus can further include an expandable impeller support having an arcuate outer surface in contact with the support structure at least when the expandable distal portion has the operational profile. The apparatus can further include a re-sealable member disposed distally of the impeller. Operation of the motor can cause rotation of the impeller to draw blood into the lumen. The re-sealable member can reseal along the path through the re-sealable member when the guidewire is removed. In some embodiments, the re-sealable member can be a septum of varying shapes, with varying path lengths through the septum. In other embodiments, the re-sealable member can be a duckbill valve.
A more complete appreciation of the subject matter of this application and the various advantages thereof can be realized by reference to the following detailed description, in which reference is made to the accompanying drawings in which:
More detailed descriptions of various embodiments of components for heart pumps useful to treat patients experiencing cardiac stress, including acute heart failure, are set forth below.
This application is directed to apparatuses for inducing motion of a fluid relative to the apparatus. In particular, the disclosed embodiments generally relate to various configurations for a re-sealable member disposed distally of an impeller as part of a percutaneous catheter pump. As discussed in greater detail below, a re-sealable member can be advantageous to reseal the percutaneous catheter pump following guidewire removal once the catheter pump is placed in a patient's heart. For example, in the disclosed embodiments, the re-sealable member can be a septum or a duckbill valve, with a path through the re-sealable member along a length dimension of the re-sealable member through which a guidewire can be positioned. The re-sealable member can be configured to seal when the guidewire is withdrawn from the pump. The re-sealable member as disclosed herein can act in various embodiments to seal the catheter pump once placed in the heart of a patient, facilitating the reduction of hemolysis at the operative device of the pump and the flow of pumped blood through the heart of the patient without leaks into the operative device of the pump.
With reference to
As shown in
In the stored configuration, the impeller 300 and housing 202 have a diameter that is preferably small enough to be inserted percutaneously into a patient's vascular system. Thus, it can be advantageous to fold the impeller 300 and housing 202 into a small enough stored configuration such that the housing 202 and impeller 300 can fit within the patient's veins or arteries. In some embodiments, therefore, the impeller 300 can have a diameter in the stored configuration corresponding to a catheter size between about 8 Fr and about 21 Fr. In one implementation, the impeller 300 can have a diameter in the stored state corresponding to a catheter size of about 9 Fr. In other embodiments, the impeller 300 can have a diameter in the stored configuration between about 12. Fr and about 21 Fr. For example, in one embodiment, the impeller 300 can have a diameter in the stored configuration corresponding to a catheter size of about 12-12.5 Fr.
When the impeller 300 is positioned within a chamber of the heart, however, it can be advantageous to expand the impeller 300 to have a diameter as large as possible in the expanded or deployed configuration. In general, increased diameter of the impeller 300 can advantageously increase flow rate through the pump. In some implementations, the impeller 300 can have a diameter corresponding to a catheter size greater than about 12 Fr in the deployed configuration. In other embodiments, the impeller 300 can have a diameter corresponding to a catheter size greater than about 21 Fr in the deployed or expanded configuration.
In various embodiments, it can be important to increase the flow rate of the heart pump while ensuring that the operation of the pump does not harm the subject. For example, increased flow rate of the heart pump can advantageously yield better outcomes for a patient by improving the circulation of blood within the patient. Furthermore, the pump should avoid damaging the subject. For example, if the pump induces excessive shear stresses on the blood and fluid flowing through the pump (e.g., flowing through the cannula), then the impeller can cause damage to blood cells, e.g., hemolysis. If the impeller damages a large number of blood cells, then hemolysis can lead to negative outcomes for the subject. As will be explained below, various cannula and/or impeller parameters can affect the pump's flow rate as well as conditions within the subject's body.
When activated, the pump 10 can effectively increase the flow of blood out of the heart and through the patient's vascular system. In various embodiments disclosed herein, the pump 10 can be configured to produce a maximum flow rate (e.g., low mm Hg) of greater than 4 Lpm, greater than 4.5 Lpm, greater than 5 Lpm, greater than 5.5Lpm, greater than 6 Lpm, greater than 6.5 Lpm, greater than 7 Lpm, greater than 7.5 Lpm, greater than 8 Lpm, greater than 9 Lpm, or greater than 10 Lpm. In various embodiments, the pump can be configured to produce an average flow rate of greater than 2 Lpm, greater than 2.5 Lpm, greater than 3 Lpm, greater than 3.5 Lpm, greater than 4 Lpm, greater than 4.25 Lpm, greater than 4.5 Lpm, greater than 5 Lpm, greater than 5.5 Lpm, or greater than 6 Lpm.
When a Seldinger insertion technique is used to advance the operative device to the heart, a guidewire and guidewire guide tube may be used. For example, the guidewire guide tube may be disposed through a central lumen of the catheter pump. The clinician can insert a guidewire through the guidewire guide tube, and can advance the guidewire to the heart. After advancing the operative device over the guidewire and into the heart, the guidewire and guidewire guide can be removed from the catheter pump. When the guidewire guide tube and/or the guidewire is retracted through a distal portion of a nose member, the distal portion may not adequately reseal the lumen. Accordingly, there is a need for an improved distal bearing support that provides for a re-sealable member.
A re-sealable member 514 can be inserted within a stepped region or recess near the distal end 516 of the mounting portion 508, e.g., into an enlarged portion disposed distal the enlarged portion in which the distal end 512 of the impeller shaft 505 is disposed. The re-sealable member 514 can be employed to reseal the aperture formed when the guidewire and/or guidewire guide tube 510 (e.g., made of stainless steel) is removed. In one embodiment, the re-sealable member 514 may be a septum (as shown in
In some embodiments, the re-sealable member 514 may not rotate relative to the impeller shaft 505 and/or the mounting portion 508. In other embodiments, the re-sealable member 514 may rotate with the mounting portion 508. The re-sealable member 514 can be a self-healing polymer and/or a high durometer polymer, or any other polymer suitable for resealing after removal of the guidewire guide tube 510. As shown in
In some embodiments, one method of assembly of the path 518 through the re-sealable member 514 and the opening 522 at the distal end of the re-sealable member may be piercing the re-sealable member 514 after installation of the re-sealable member 514 into the stepped region or recess near the distal end 516 of the mounting portion 508, e.g., into an enlarged portion disposed distal the enlarged portion in which the distal end 512 of the impeller shaft 505 is disposed. In other embodiments, another method of assembly of the path 518 through the re-sealable member 514 and the opening 522 at the distal end of the re-sealable member may be piercing the re-sealable member 514 prior to installation of the re-sealable member 514 into the stepped region or recess near the distal end 516 of the mounting portion 508, e.g., into an enlarged portion disposed distal the enlarged portion in which the distal end 512 of the impeller shaft 505 is disposed.
In the implementation of
Modifications of catheter pumps incorporating a catheter assembly with a distal impeller support can be used for right side support. For example, a catheter body carrying an impeller and distal bearing support can be formed to have a deployed shape corresponding to the shape of the vasculature traversed between a peripheral vascular access point and the right ventricle. One will appreciate from the description herein that the catheter assembly may be modified based on the respective anatomy to suit the desired vascular approach. For example, the catheter assembly in the insertion state may be shaped for introduction through the subclavian artery to the heart. The catheter pump may be configured for insertion through a smaller opening and with a lower average flow rate for right side support. In various embodiments, the catheter assembly is scaled up for a higher flow rate for sicker patients and/or larger patients.
Although the inventions herein have been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present inventions. It is therefore to be understood that numerous modifications can be made to the illustrative embodiments and that other arrangements can be devised without departing from the spirit and scope of the present inventions as defined by the appended claims. Thus, it is intended that the present application cover the modifications and variations of these embodiments and their equivalents.
This application claims the benefit of priority to U.S. Provisional Patent Application No. 63/294,213, filed Dec. 28, 2021, the contents and disclosure of which are incorporated by reference herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63294213 | Dec 2021 | US |
