Devices for pumping blood, related systems, and related methods

An intravascular device for pumping blood includes a catheter comprising a membrane chamber located between a proximal end and a distal end of the catheter. An inflatable membrane is disposed within the membrane chamber. The intravascular device includes a first one-way valve and optionally a second one-way valve configured to permit blood flow in a first direction. The first one-way valve may be positioned proximal to the membrane chamber, and the second one-way valve may be positioned distal to the membrane chamber. Methods related to intravascular devices and their respective use are provided.

TECHNICAL FIELD

The present disclosure relates to intravascular blood pumps such as ventricular assist devices (VADs), and more particularly relates to right ventricular assist devices (RVADs) and left ventricular assist devices (LVADs).

BACKGROUND

One prior art intravascular blood pump is described in U.S. Pat. No. 5,928,132 to Leschinsky, the entire contents of which are incorporated by reference herein. The Leschinsky device includes a catheter with an inflatable balloon positioned within a pumping chamber at or near a distal end of the catheter. The balloon is alternately inflated and deflated by an external pump drive. Deflation of the balloon within pumping chamber of the catheter allows blood to flow into the pumping chamber from the heart. Inflation of the balloon displaces the blood and causes the blood to be expelled from the catheter through outlet valves positioned, for example, on the pumping chamber, thereby supporting the heart. Leschinsky notes that with minor variations, such a device may be used as a right ventricular assist device.

Challenges exist in providing intravascular blood pumping devices that are optimally effective given variations in patient anatomy, such as differences in diameter of aorta or vena cava between patients. Design challenges relate to the need to balance maximizing cannula size for maximum blood flow and reducing cannula size to improve blood flow around and external to the cannula as well as permit smaller profiles for insertion through narrow portions of a patient's vasculature. Further, elements on the cannula itself may reduce or slow blood flow around the cannula. Improvements to device safety and manufacturability are also desired.

SUMMARY

In one aspect of the disclosure, an intravascular device for pumping blood includes a catheter comprising a membrane chamber located between a proximal end and a distal end of the catheter, an inflatable membrane disposed within the membrane chamber, and a valve chamber separate from the membrane chamber. The intravascular device includes a first one-way valve configured to permit blood flow in a first direction.

In another aspect of the disclosure, an intravascular device for pumping blood includes a catheter comprising a membrane chamber located between a proximal tube portion and a distal tube portion. The proximal and distal tube portions each have a profile, when viewed along a lengthwise direction of the device, smaller than the outer profile of the membrane chamber. An inflatable membrane is disposed within the membrane chamber. The intravascular device further includes a first one-way valve associated with a first valve chamber of the catheter, the first valve chamber having a profile, when viewed along a lengthwise direction of the device, smaller than the profile of the membrane chamber.

In yet another aspect of the disclosure, a system for pumping blood includes an intravascular device comprising a catheter comprising a membrane chamber located between a proximal end and a distal end of the catheter, an inflatable membrane disposed within the membrane chamber, and an inlet and an outlet positioned external to and in fluid communication with the membrane chamber. The system further includes a connector assembly configured to connect to the intravascular device and to a pump console and configured to allow settings on the pump console to be altered for use with the intravascular device.

In yet another aspect of the disclosure, a method of forming an intravascular device includes forming at least one valve chamber, the chamber comprising a one-way valve, forming a membrane chamber of an expandable material, the membrane chamber having an expanded configuration and a contracted configuration, coupling at least one valve chamber to the membrane chamber, and coupling a catheter tube to the valve chamber.

In yet another aspect of the disclosure, a method of assisting circulation of blood in a body includes inserting a catheter into a venous structure. The catheter comprises a membrane chamber located between a proximal end and a distal end of the catheter. An inflatable membrane is disposed within the membrane chamber. The catheter includes a first valve chamber forming a portion of or containing a first one-way valve configured to permit blood flow in a first direction, and the first one-way valve is positioned proximal to the membrane chamber. The method further includes positioning the catheter such that the first valve chamber is positioned substantially adjacent to one of a renal vein and a hepatic vein, expanding the membrane chamber from a contracted position to an expanded position, and cyclically supplying a fluid to the inflatable membrane to inflate and deflate the inflatable membrane. Inflation of the membrane permits blood to exit the catheter and deflation of the membrane permits blood to enter the catheter through the first one-way valve.

In yet another aspect of the disclosure, a method of assisting circulation of blood in a body includes inserting a catheter into an arterial structure. The catheter comprises a membrane chamber located between a proximal end and a distal end of the catheter, an inflatable membrane disposed within the membrane chamber, and a first valve chamber forming a portion of or containing a first one-way valve configured to permit blood flow in a first direction. The first valve chamber is positioned proximal to the membrane chamber. The method further includes positioning the catheter such that the first valve chamber is substantially adjacent to a renal artery, expanding the membrane chamber from a contracted position to an expanded position, and cyclically supplying a fluid to the inflatable membrane to inflate and deflate the inflatable membrane, wherein inflation of the membrane permits blood to exit the catheter through the first one-way valve and deflation of the membrane permits blood to enter the catheter.

In accordance with yet another aspect of the present disclosure, an intravascular device for pumping blood includes a catheter comprising a membrane chamber located between a proximal tube portion and a distal tube portion with a distal end. At least one one-way valve is located proximal to or distal to the membrane chamber. The at least one one-way valve is positioned along a length of the device and relative to the distal end such that when the distal end is positioned at a target location relative to a first vascular structure, the at least one one-way valve is positioned adjacent a second vascular structure different from the first vascular structure.

Additional objects, features, and/or other advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present disclosure and/or claims. At least some of these objects and advantages may be realized and attained by the elements and combinations particularly pointed out in the appended claims.

Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claims; rather the claims should be entitled to their full breadth of scope, including equivalents.

DETAILED DESCRIPTION

This description and the accompanying drawings that illustrate exemplary embodiments should not be taken as limiting. Various mechanical, compositional, structural, electrical, and operational changes may be made without departing from the scope of this description and the claims, including equivalents. In some instances, well-known structures and techniques have not been shown or described in detail so as not to obscure the disclosure. Like numbers in two or more figures represent the same or similar elements. Furthermore, elements and their associated features that are described in detail with reference to one embodiment may, whenever practical, be included in other embodiments in which they are not specifically shown or described. For example, if an element is described in detail with reference to one embodiment and is not described with reference to a second embodiment, the element may nevertheless be claimed as included in the second embodiment.

Further, this description's terminology is not intended to limit the disclosure. For example, spatially relative terms—such as “beneath”, “below”, “lower”, “above”, “upper”, “proximal”, “distal”, and the like—may be used to describe one element's or feature's relationship to another element or feature as illustrated in the figures. These spatially relative terms are intended to encompass different positions (i.e., locations) and orientations (i.e., rotational placements) of a device in use or operation in addition to the position and orientation shown in the figures. For example, if a device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be “above” or “over” the other elements or features. Thus, the exemplary term “below” can encompass both positions and orientations of above and below. A device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Likewise, descriptions of movement along and around various axes includes various special device positions and orientations. In addition, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context indicates otherwise. And, the terms “comprises”, “comprising”, “includes”, and the like specify the presence of stated features, steps, operations, elements, and/or components but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups. Components described as coupled may be electrically or mechanically directly coupled, or they may be indirectly coupled via one or more intermediate components. Mathematical and geometric terms are not necessarily intended to be used in accordance with their strict definitions unless the context of the description indicates otherwise, because a person having ordinary skill in the art would understand that, for example, a substantially similar element that functions in a substantially similar way could easily fall within the scope of a descriptive term even though the term also has a strict definition.

Various exemplary embodiments of the present disclosure contemplate systems, methods, and devices that assist a patient's heart in pumping blood through the left or right heart chambers. In accordance with the present disclosure, an intravascular device (also referred to herein as a device for pumping blood and as a ventricular assist device) comprises a membrane chamber for moving blood into and out of the intravascular device. The membrane chamber contains (or is otherwise configured to receive internally) an inflatable balloon membrane that can be cyclically inflated and deflated to move blood into and out of the intravascular device through inlet and outlet valves of the device. In accordance with one aspect of the present disclosure, the intravascular devices may be configured to reduce (e.g., minimize) interference between anatomical structures of the patient and inlet and/or outlet valves of the intravascular device. For example, in certain exemplary embodiments, the valves may be located on portions of the intravascular device that have an outer diameter less than a maximum outer diameter of the membrane chamber containing the balloon membrane of the intravascular device. Locating the valves off the membrane chamber serves several purposes, permitting maximum flow around the device within a blood vessel while also permitting the valves to open to their full extent, to maximize inflow and outflow of blood through the membrane chamber. In addition, the size of the membrane chamber need not be limited by the need for valves on the chamber to open, thus allowing the size of the membrane chamber to be maximized. Stated another way, the size of the membrane chamber is limited when valves are located on the membrane chamber, because the chamber must be small enough to allow the valves to open without contacting the surrounding blood vessel. While this disclosure provides several embodiments in which all valves are located off the membrane chamber, it is within the scope of the present disclosure to include one or more valves on the membrane chamber as well, as will be discussed with respect to the exemplary embodiment ofFIG. 11below. In such an embodiment, it may be desirable to locate the valve(s) on the chamber in such a way that the size of the membrane chamber need not be limited to permit the valves to fully open.

Locating the valves off the membrane chamber may also increase ease of manufacturing of the device. In certain exemplary embodiments, the valves may be positioned in valve chambers separate from the membrane chamber. In certain embodiments, the membrane chamber is valveless, meaning that there are no valves formed in the membrane chamber, or in any sidewall of the membrane chamber, or on any sidewall of the membrane chamber. The valve chamber may comprise a volume in fluid communication with the membrane chamber as well as other portions of the catheter. The valve chamber may take several different forms. For example, the valve chamber may be a part of one or both of a proximal or distal tube portion of the catheter. In such an embodiment, the portion of the proximal or distal tube may be expanded or ballooned to have a diameter that is larger than the remaining portion of the proximal or distal tube, and a one-way valve, such as an inlet or an outlet valve, may be positioned within the expanded or ballooned portion of the tube (i.e., in the valve chamber). In another exemplary embodiment, the valve chamber may take the form of an inlet tube or an outlet tube. The inlet tube or outlet tube may contain an inlet valve or outlet valve, respectively, placed into fluid communication with the membrane chamber, with the inlet tube or outlet tube extending substantially in parallel with proximal or distal tube portions of the catheter. Additionally, or alternatively, the valve chamber may take the form of a separate valve assembly that includes a valve chamber containing one or more valves, such as inlet valves or outlet valves, and the valves may include respective valve housings, or may be housed by a common housing. In such a case, the valve assemblies may be manufactured separately from other portions of the intravascular device, such as the membrane chamber and tubes, and may be coupled with the other portions of the intravascular device to form the complete intravascular device. The valve chamber may take on other configurations which place the valve(s) contained therein in fluid communication with the membrane chamber, as will be apparent to those of skill in the art.

Utilizing valve subassemblies in the device, in addition to improving manufacturability, also allows for a level of customization of the device. That is, the valve subassemblies can be located to accommodate variations in patient anatomy and can be located to direct blood flow to preferred anatomical areas. For example, in accordance with another aspect of the present disclosure, the inlet and/or outlet valves of the intravascular device may be positioned to optimally supply flow to various anatomical locations, such as to provide or otherwise cause improved (e.g., optimal) cerebral and/or renal perfusion. For example, in some exemplary embodiments of the disclosure, the intravascular device may include multiple outlet valve locations. For example, as illustrated inFIGS. 3 and 4, an intravascular device in accordance with the present disclosure may include a first outlet valve located distal to or proximal to the membrane chamber. Optionally, the intravascular device may have a second outlet valve located proximal to the membrane chamber (when the first outlet valve is located distal to the membrane chamber) or distal to the membrane chamber (when the first outlet valve is located proximal to the membrane chamber). Additionally, in other exemplary embodiments of the device, the intravascular device may include multiple inlet locations. For example, an intravascular device in accordance with the present disclosure when adapted for a right heart support application may include a first inlet valve located on the device to be positioned adjacent a hepatic vein and a second inlet valve located on the device to be positioned adjacent a renal vein. Both inlet valves in such a configuration may be located proximal to the membrane chamber, and the intravascular device may have an outlet located at its distal end region. Alternatively, or additionally, one of the inlet valves may be located on the membrane chamber as shown in the exemplary embodiment ofFIG. 11.

In accordance with another aspect of the present disclosure, the intravascular device may include features configured to interface with a console of a pump drive that supplies a flow of working fluid (such as a gas) to alternately inflate and deflate the balloon membrane within the membrane chamber (i.e., the balloon membrane housing). For example, in some exemplary embodiments, the intravascular device includes a transducer such as a pressure transducer that is configured to provide a pressure signal to the pump drive. The pressure signal may be used to control aspects of the pump drive action, such as timing of inflation and deflation cycles, dwell times at an inflated or deflated state, or other aspects of the pump drive action. Additionally, or alternatively, the pressure signal may be used to provide pressure information at a user interface of the pump drive console. Other transducers such as sound transducers may be utilized instead of or in addition to a pressure transducer to be used to control aspects of the pump drive action.

The console of the pump drive may include various pre-programmed pumping algorithms which may be selected to provide optimized pumping action based on parameters such as the type of intravascular device being used, certain aspects of the patient's anatomy, and the patient's response to assist treatment, and other factors such as the patient's hemodynamics before therapy, the degree of valvular insufficiency, and the patient's response to other therapies. Additionally, the console of the pump drive may be configured to enable a practitioner to manually set aspects of the pumping action based on, for example, factors such as those above. In some exemplary embodiments, the intravascular device may include an identification device that provides information regarding operating characteristics of the intravascular device to the pump drive console to enable the pump drive console or the practitioner to choose suitable operating parameters for the pumping action. In accordance with one aspect of the present disclosure, connection to the identification device may cause the pump console to display a user interface configured for the intravascular device. For example, connection with the identification device may cause a display on the pump console to automatically change from operational settings for a first operational mode to a second operational mode that includes operating settings for use with an intravascular device. The types of settings for an intravascular device that might be displayed and controlled through the pump console may relate to, for example, alarm settings, detection settings, alarm conditions, device cycle triggering, device cycle timing, and user interface settings. In certain embodiments, the identification device is a radio-frequency identification (RFID) device incorporated into the intravascular device.

Referring now toFIG. 1, an exemplary embodiment of an intravascular device100is shown. In the embodiment ofFIG. 1, the intravascular device100is configured to support the right heart, and therefore may be referred to as a right ventricular assist device (“RVAD”). The intravascular device100comprises a membrane chamber104. A membrane or diaphragm or balloon that is configured to expand and contract (or inflate and deflate or otherwise change the occupied volume in the membrane chamber104) is positioned within the membrane chamber to provide the pumping function. Such membranes or diaphragms may be referred to interchangeably herein as expandable or inflatable membranes or balloon membranes or intra-aortic balloons (IABs) (although it is anticipated to also use a balloon member other than that used on an IAB). These membranes may be formed, for example, from polymers or other flexible materials. As non-limiting examples, the membranes may comprise polyurethane, silicone, or other polymers. Further examples of membranes and materials they may incorporate may be found in U.S. Pat. No. 6,482,173, issued on Nov. 19, 2002, the entire contents of which are incorporated by reference herein. Additionally, in certain embodiments the balloon may be distensible and in other embodiments the balloon may be non-distensible. In the exemplary embodiment ofFIG. 1, an inflatable membrane balloon106used in intra-aortic balloon (IAB) devices, is positioned within membrane chamber104. A tube102is in fluid communication with and extends proximally from membrane chamber104. The tube102may be referred to as a proximal tube portion. As used herein, the term “proximal” refers to a direction along the intravascular device100toward an end of the device that remains outside the patient's body and is connected to external equipment such as a pump console640(shown inFIGS. 6 and 7), and the term “distal” refers a direction along the intravascular device100toward an end of the device opposite the proximal end, such as a free end of the device being configured for placement within patient's right or left heart. The tube102may extend all the way out of the patient, e.g., to the pump console640, or the tube102may not extend out of the patient and may seal against the outer surface of tube116to prevent blood leakage during pumping.

A tube108is in fluid communication with and extends distally from membrane chamber104and includes an outlet valve110and an open distal end111. The tube108may be referred to as a distal tube portion. In an exemplary embodiment, the outlet valve110may be a one-way valve, such as a check valve, that opens or closes based on relative pressures present on either side of the outlet valve110. In some exemplary embodiments, the tube108may have a “J” shape or be coupled to a “J” shaped extension or pigtail. Such a configuration may prevent the open distal end111from becoming occluded by vascular walls when in position within a patient. Extensions having such configurations are shown in, for example, U.S. Patent App. Pub. No. US2010/0268017 A1 to Siess, published on Oct. 21, 2010, and U.S. Pat. No. 9,545,468 to Aboul-Hosn, granted Jan. 17, 2017, the entire contents of each of which are incorporated by reference herein. An inlet valve112is disposed in an inlet valve chamber114located between and in fluid communication with the tube102and the membrane chamber104. Similar to the outlet valve110, in an exemplary embodiment, the inlet valve112may be a one-way valve such as a check valve that operates based on a pressure differential on either side of the inlet valve112. The inlet valve112and inlet valve chamber114may be referred to as a valve subassembly. In some exemplary embodiments, the inlet valve112may be disposed directly on the tube102, or on an expanded portion of the tube102. In an exemplary embodiment, the inlet valve112may comprise one or more film flaps connected at one end to the inlet valve chamber112or tube102. In other exemplary embodiments, the valve112may comprise a flapper valve, a duckbill valve, or other valve configurations.

The membrane balloon106is connected to an external fluid supply, such as a supply of shuttle gas from a pump console640(shown in connection withFIGS. 6 and 7) that alternatingly inflates and deflates the membrane balloon106within the membrane chamber104. As a non-limiting example, the gas supplied may be helium to prevent formation of an embolism in the event the gas escapes from the intravascular device100and into the patient's bloodstream. As will be understood by those of ordinary skill in the art, other appropriate gasses or fluids may be used to inflate the membrane balloon106. The gas may be supplied through a shaft116of the device that is in fluid communication with the membrane balloon106and that passes through the tube102and receives the supply of gas from the pump console640.

In use, the membrane chamber104of the device is in a compressed or contracted configuration prior to insertion, to reduce the overall profile of the device and allow for percutaneous insertion. For right-heart circulatory support, the device may be inserted into the right subclavian vein to access the superior vena cava, the right atrium, or right ventricle. Additionally, the femoral vein may be used to access the inferior vena cava, right atrium, or right ventricle when used for right-heart circulatory support. For left-heart support, the left femoral artery may be used to access the aorta. While various embodiments of the disclosure are described herein in terms of percutaneous insertion, the disclosure contemplates insertion in other ways, such as direct aortic insertion or surgical cut-down insertion. The membrane chamber (and other portions of the device) may incorporate, for example, a self-expanding material to move from the contracted configuration to the expanded configuration on its own after insertion into and positioning within the blood vessel. Examples of such structures include for example those disclosed in U.S. Patent App. Pub. No. US2012/0172655 and PCT publication WO2012094525 to Campbell et al., as well as those disclosed in PCT publication WO2013173245 to Zeng et al., the entire contents of each publication are incorporated by reference herein. Examples of materials that may be used for such self-expanding structures include shape memory materials. As non-limiting examples, such shape memory materials may include shape-memory alloys (SMAs) such as nitinol (NiTi), Fe—Mn—Si, Cu—Zn—Al, Cu—Al—Ni, or other SMAs, and shape memory polymers (SMPs), such as polyurethane-based, polystyrene-based, cyanate ester-based, and epoxy-based SMPs. Alternatively, a compressible material having sufficient “spring back” (i.e., a material having a sufficiently high elastic modulus) to expand after being compressed for insertion may be used. Examples of suitable materials include, for example, stainless steel or other metals or metal alloys, or polymers such as polyimide or polyether ether ketone (PEEK). In such an embodiment, it may be desirable to use a sheath or other sleeve like member to maintain the membrane chamber in a compressed configuration during insertion. The sheath can be withdrawn after placement of the device. As another alternative, the material used may not be self-expandable. In such a case, expansion and retraction of the membrane chamber may occur through other mechanical methods such as, for example, those disclosed in U.S. Pat. No. 4,444,186, which is incorporated herein by reference in its entirety. With the membrane chamber in a compressed or contracted configuration, the distal end111of the device is inserted percutaneously through an incision in the patient's body and into an arterial or venous structure such as, for example, the femoral artery or the femoral vein. As will be understood by those of ordinary skill in the art, other insertion sites such as axillary, subclavian, or brachiocephalic arteries or veins may be used, depending upon the specifics of the device and patient. The exemplary embodiment shown inFIG. 1is a RVAD configured to assist in moving blood from the vena cava, the right atrium, or the right ventricle to the lungs via the pulmonary artery and/or across the heart, and in an exemplary use, the device may be inserted through the femoral vein and guided into the inferior vena cava (IVC) with the distal end111of the outlet tube108positioned to provide outlet flow from the outlet valve110to the patient's pulmonary trunk. The inlet valve chamber114may be positioned in the IVC, the right atrium, or the right ventricle. In other exemplary embodiments, the device may be inserted through the superior vena cava, depending on the specific therapeutic needs of the patient and factors related to the patient's anatomy. When the balloon is in a deflated state, blood pressure in the vena cava, the right atrium, or the right ventricle, depending on where the inlet valve chamber114is positioned, causes the inlet valve112to open and allow blood to flow into the membrane chamber104around the deflated membrane balloon106. The outlet valve110remains closed while the membrane chamber104fills with blood. Once the membrane chamber104is filled, inflation of the membrane balloon106causes the pressure to rise in the membrane chamber104above the pressure in the right atrium or ventricle, causing the inlet valve112to close, thereby preventing retrograde flow of blood due to balloon inflation. Pressure in the membrane chamber104causes the outlet valve110to open, and blood is expelled from the membrane chamber104, through the outlet tube108, and into the pulmonary artery. In this manner, the intravascular device100assists the right heart in pumping blood from the vena cava, right atrium, or right ventricle to the pulmonary artery.

Various configurations of the inlet valve112and outlet valve110are possible, including such configurations in which the outlet valve110is not present. For example, in the exemplary embodiment ofFIG. 1, the inlet valve112is contained within the inlet valve chamber114. The inlet valve chamber114and inlet valve112may be manufactured as a separate assembly from the membrane chamber104, and may be coupled to the membrane chamber104and the tube102to form the intravascular device100. For example, an assembly of the inlet valve chamber114and the inlet valve112may be coupled with the membrane chamber104or tube102by bonding using, e.g., adhesives, welding such as ultrasonic, friction, or laser welding, or any other method. The valve chamber114may, in certain embodiments, be formed as a dilated or ballooned portion of the tube102as described below. Forming the inlet valve assembly separate from the membrane chamber104affords flexibility in manufacturing the inlet valve assembly and the membrane chamber. For example, in some exemplary embodiments, manufacturing or bonding elements of the valves to other components of the device involves thermal or chemical processes. By manufacturing the valve assembly separate from other components of the device, adverse effects of such thermal or chemical processes on other components of the device may be reduced or eliminated.

Additionally, manufacturing the valve chamber114separate from the membrane chamber104provides additional flexibility regarding the position of the valves relative to the membrane chamber104. For example, the longitudinal position of the valve assembly relative to the membrane chamber104can be changed by, for example, including a tube of desired length between the membrane chamber104and the valve assembly (as shown and discussed in connection with the exemplary embodiment ofFIG. 3). In this way, the position of the valves may be tailored to improve (e.g., optimize) the efficacy of the intravascular device by positioning the valves in locations that improve perfusion of blood to anatomical structures and, alternatively or additionally, reduce the tendency of anatomical structures to partly or fully occlude the valves.

As an exemplary alternative to providing a separate chamber for the valve114, the inlet valve chamber114may be formed by expanding a portion of the tube102to form the inlet valve chamber114. For example, a portion of the tube102could be expanded by heating and pressurizing the tube102within a mandrel that molds the tube102to the desired shape, by swaging the tube102, or by any other method. As a further non-limiting example, the inlet valve chamber114may be formed as a reduced-diameter tube in fluidic communication with the membrane chamber104, which is mechanically or chemically bonded to the tube102.

An outer lateral dimension of the inlet valve chamber114may be less than a corresponding outer lateral dimension of the membrane chamber104. The lateral dimension may also be referred to as a profile dimension, or an outer profile. The profile may refer to the profile of the membrane chamber104as viewed along a lengthwise direction of the device. For example, the inlet valve chamber114may have an outer diameter Dh that is less than an outer diameter Dc of the membrane chamber104. The diameter Dh of the inlet valve chamber114may be greater than an outer diameter DT of the outlet tube108and proximal tube102. The reduced outside diameter of the intake valve chamber114relative to the diameter Dc of the membrane chamber104may facilitate operation of the valves without occlusion by anatomical structures. For example, because the inlet valve chamber114diameter Dh is less than diameter Dc of the membrane chamber104, when the membrane chamber104is in position within a patient's heart, the smaller diameter Dh of the inlet valve chamber114may provide clearance between anatomical walls and the inlet valve112, thereby potentially avoiding occlusion of the inlet valve112. This also allows for increased blood flow within the blood vessel and around the membrane chamber104. Also, the smaller diameter of the inlet valve chamber114presents less of an obstruction and decreases the resistance to blood flowing around the outer surfaces of the intravascular device100than if the inlet valve chamber114and the membrane chamber104had the same diameter when fully deployed or expanded. Further, although optional outlet valve110is shown contained within tube108inFIG. 1, the present disclosure contemplates that outlet valve110may also be contained within a housing separate from the tube108, or formed in an expanded portion of the tube108. While the outer lateral dimensions of the membrane chamber104, the inlet valve chamber114, and the tubes102and108are discussed in terms of diameter, the membrane chamber104, the inlet valve chamber114, and the tubes102and108are not limited to having a circular cross-section. For example, a cross section of the membrane chamber104, the inlet valve chamber114, the tube102, and/or tube108may be, as non-limiting examples, ovoid, square, rectangular, or have other polygonal or non-polygonal shapes.

As shown inFIG. 1, the membrane chamber104comprises a length LC, and the inlet valve chamber114comprises a length LH. The length LC of the membrane chamber104may be greater than the length LH of the inlet valve chamber114. Additionally, the membrane chamber104may comprise an interior volume defined by interior shape and dimensions of the membrane chamber104. The inlet valve chamber114may comprise an interior volume defined by the interior shape and dimensions of the inlet valve chamber114. The interior volume of the membrane chamber104may be greater than the interior volume of the inlet valve chamber114.

In some exemplary embodiments, the intravascular device100may include markers117positioned adjacent the inlet valve112and the end of the outlet tube108to aid a practitioner in positioning the intravascular device100so that the valves are located optimally for effective uptake and perfusion of blood. The markers117may comprise a radiopaque material that is visible in x-ray and under fluoroscopy, such as a halogen or metallic compound. Non-limiting examples of such radiopaque materials include tungsten, tantalum, or BaSO4 (barium sulfate).

In some exemplary embodiments, portions of the intravascular device100may include an anti-thrombogenic coating to reduce the occurrence of thrombi formation. Such a coating may be applied to the entire intravascular device100, or only portions of the intravascular device100, such as in, on and/or near the valve chambers, the membrane chamber104, etc. The coating may be applied to the exterior and/or interior of the device. The coating may be an immobilized heparin coating formed by alternating layers of albumen and heparin, or may include other combinations of heparin and/or albumen. One example of such an immobilized heparin coating is BIOLINE®, available from Maquet Cardiovascular, LLC, 45 Barbour Pond Drive, Wayne, N.J., 07470 USA.

In some embodiments, the inlet valve chamber may comprise an inlet tube with an open end and an inlet valve positioned within the inlet tube. For example, referring now toFIG. 2, an intravascular device200includes an inlet tube218with an open end220and an inlet valve212disposed in the inlet tube218. The intravascular device200also includes an outlet tube208with an outer diameter DT and an outlet valve210within the outlet tube208. In the exemplary example ofFIG. 2, the inlet tube218is coupled with a membrane chamber204, and the inlet tube218is positioned offset from a central axis Ac of the membrane chamber204, and a tube202is positioned coaxial with the central axis Ac of the membrane chamber204. In other embodiments, the tube202may be offset relative to the central axis Ac, and the inlet tube218may be positioned coaxial with, or offset relative to, the central axis Ac of the membrane chamber204.

The inlet tube218may have an outer diameter DT, and a length L chosen to position the open end220of the inlet tube218in an optimal position for drawing blood into the membrane chamber204from the anatomical structure in which the intravascular device is positioned. Similar to the embodiment ofFIG. 1, the configuration of the inlet tube218, such as the length L, may be chosen to avoid occlusion of the open end220of the inlet tube218by anatomical structures of the patient.

Referring now toFIG. 3, another exemplary embodiment of an intravascular device300is shown. In the embodiment ofFIG. 3, the intravascular device300is configured to support the left heart, and may be referred to as a left ventricular assist device (“LVAD”). The intravascular device300includes a membrane chamber304containing a membrane balloon306configured to communicate with a pump console (e.g., pump device console640shown inFIGS. 6 and 7). An inlet tube308extends from a distal portion of the membrane chamber304, and includes an inlet valve312located at a location distal to the membrane chamber, such as at open end330of the inlet tube308. The intravascular device includes first and second outlet valve chambers322and324, each chamber may be provided with a housing including an outlet valve310. The first outlet valve chamber322is positioned distal to the membrane chamber304and proximal to the inlet valve312, and the second outlet valve chamber324is positioned proximal to the membrane chamber304.

As with the inlet valve chamber114discussed in connection with the embodiment ofFIG. 1, the outlet valve chambers322and324may be manufactured separately from the membrane chamber304and then attached to the membrane chamber304, as is the outlet valve chamber324in the exemplary embodiment ofFIG. 3, or attached to the membrane chamber304by a portion of the inlet tube308, as shown in the exemplary embodiment ofFIG. 3with respect to outlet valve chamber322. Alternatively, the outlet valve chambers322,324may be formed by expanding a portion of the tube308, and positioning the outlet valves310in the expanded portion of the tube308. Positioning multiple outlet valve chambers (e.g., outlet valve chambers322and324) along the length of the intravascular device300may enable blood flow to be directed to specific areas to optimize perfusion, e.g., cerebral and renal perfusion of blood from the intravascular device300. For example, in the embodiment ofFIG. 3, the outlet valve chambers322and324are configured to be positioned adjacent the common carotid artery and the renal arteries. Although the embodiment ofFIG. 3is illustrated with two outlet valve chambers, it is within the scope of this disclosure to provide additional valve chambers either proximal and/or distal to the membrane chamber depending upon a physiologic need.

Similar to the inlet valve chamber114discussed in connection with the embodiment ofFIG. 1, the outlet valve chambers322and324have an outside diameter Dh that is less than the outer diameter Dc of the membrane chamber304. Such a configuration may prevent interference with or occlusion of the outlet valves310when the intravascular device is positioned with the anatomical structure, particularly in configurations where the outlet valves310open outward, as shown inFIG. 3. This also allows for increased blood flow within the blood vessel and around the membrane chamber304. Further, although inlet valve312is shown contained within the end of tube308inFIG. 3, the present disclosure contemplates that inlet valve312may also be contained within a chamber. Further, the present disclosure also contemplates that the outer diameter Dh of chambers322and324may be greater than an outer diameter DT of tubes302and308. Additionally, in some embodiments, the outer diameter Dh of the chambers (such as chambers322and324) may be greater than an outer diameter Dc of the membrane chamber304.

In use, the membrane chamber304of the device is in a compressed or contracted configuration prior to and during insertion, to reduce the overall profile of the device and allow for percutaneous insertion. Additionally, one or both of the tubes302and308may be introduced in a furled (i.e., reduced diameter) state to reduce the overall diameter of the device to facilitate insertion. The membrane chamber (and other portions of the device) may incorporate, for example, a self-expanding material to move from the contracted configuration to the expanded configuration on its own after insertion into and positioning within the blood vessel. Examples of such self-expanding materials include shape memory materials such as the SMAs and SMPs listed above in connection with the embodiment ofFIG. 1. Alternatively, a compressible material having sufficient “spring back” to expand after being compressed for insertion may be used. Examples of suitable materials include materials exhibiting high elastic moduli, such as the materials listed above in connection with the embodiment ofFIG. 1. In such an embodiment, it may be desirable to use a sheath or other sleeve like member to maintain the membrane chamber in a compressed configuration during insertion. The sheath can be withdrawn after placement of the device. As another alternative, the material used may not be self-expandable. In such a case, expansion and retraction of the membrane chamber may occur through other mechanical methods such as, for example, those disclosed in U.S. Pat. No. 4,444,186, which is incorporated herein by reference in its entirety, and by those disclosed in U.S. Pat. No. 5,928,132, which is also incorporated herein by reference. With the membrane chamber in a compressed or contracted configuration, the intravascular device300may be percutaneously inserted through a patient's femoral artery, for example, until the inlet tube308is positioned in the patient's left ventricle and the outlet valve chambers322and324and the membrane chamber304are positioned within the patient's aorta. As previously noted, one or more of the outlet valve chambers may have markings, such as radiopaque markers317, that allow the housings to be viewed during insertion via fluoroscopy. This permits the surgeon to adjust and then observe position of one or both of the outlet valves to maximize perfusion, for example, cerebral perfusion or renal perfusion. This application also contemplates that the markers may be positioned near to or adjacent to the valves and not always on the valve chambers. For example, markers may be positioned on tubing immediately proximal or immediately distal to a valve chamber.

The shaft316connects membrane balloon306to pump console640(FIGS. 6 and 7) to allow cyclical inflation of balloon membrane306with gas or other fluid supplied by pump console640to inflate and deflate balloon membrane306. In use, when the membrane balloon306is in a deflated state, blood pressure in the left ventricle causes the inlet valve312to open, and blood enters the membrane chamber304through tube308. When the membrane balloon306is inflated, the increased pressure in the membrane chamber304causes the inlet valve312to close to prevent retrograde flow through the opening330, and blood is expelled from the membrane chamber304through the outlet valves310.

In addition to tailoring the position of each of the outlet valves310to increase (e.g., maximize) perfusion of blood to particular anatomical structures, the flow rates of each of the outlet valves310may make up a different proportion of a total flow rate from the intravascular device300. For example, an outlet valve positioned farther from the membrane chamber304may have a lower flow rate as compared to an outlet valve positioned closer to the membrane chamber304due to losses (e.g., frictional factors) in the tube308. Additionally, different outlet valves310may have different flow areas (e.g., cross sectional areas) to provide different overall flow rates as between different valves. For example, the outlet valves310may be configured so that half of the pumping volume goes through the proximal valve and half of the pumping volume goes through the distal valve. However, depending upon estimated needs for a patient, the split in total flow volume to proximal and distal outlet valves310may be divided 60:40, 70:30, 40:60 or 30:70, if desired, depending upon valve configuration and desired perfusion strategies. As a non-limiting example, the flow rate adjacent to the renal arteries may be made larger than the flow rate adjacent to the common carotid, brachiocephalic and subclavian arteries if such an arrangement would be beneficial to patient recovery. Alternatively, to ensure appropriate flow to the upper branches of the aorta, the flow rate of the device may be made larger in that area.FIG. 4shows a left intravascular device400similar to the intravascular device300ofFIG. 3. In the embodiment ofFIG. 4, outlet valves410are proximal to a membrane chamber404and an inlet tube408, and distal to a proximal tube402having an outer diameter DT. The inlet tube408has an outer diameter DT and extends distally from the membrane chamber404and includes an inlet valve412and another outlet valve410. The potential for interference with or occlusion of the outlet valves410by anatomical structures when the intravascular device is positioned within a patient's body is reduced by locating the outlet valves410in portions of the intravascular device having a smaller outer diameter than the outer diameter of the membrane chamber404. In the embodiment ofFIG. 4, the outlet valves410are incorporated into a structure of the device400having an outer diameter similar or equal to the outer diameter DT of the inlet tube408and the proximal tube402. For example, the outlet valves410may be located within valve chambers (not shown inFIG. 4) similar to the embodiment ofFIG. 3, or the outlet valves410could be located within expanded portions of the tube402or inlet tube408. The outlet valves410located distal to the membrane chamber404are in a more proximal location as compared to the analogous outlet valves310shown inFIG. 3. Such differing valve placement may facilitate perfusion to different areas of the patient's anatomy compared to the embodiment ofFIG. 3, or may be tailored to compensate for differences in anatomy between patients.

Referring now toFIG. 5, yet another embodiment of an intravascular device500is shown. The intravascular device500is a right intravascular device similar in function to the intravascular devices100and200described in connection withFIGS. 1 and 2. In the embodiment ofFIG. 5, the intravascular device500includes an inlet valve chamber514with inlet valves512positioned therein. The inlet valve chamber514is coupled to a membrane chamber504containing a membrane balloon506. The inlet valve chamber514is offset relative to the central axis of the membrane chamber504, and the inlet valve chamber514may be connected to a proximal tube502at a location offset from the location at which the inlet valve chamber514is connected to the membrane chamber504. The membrane chamber504is connected to a distal outlet tube508provided with an outlet valve510.

The offset of the inlet valve chamber514may be chosen to position the inlet valve chamber514in such a way as to avoid occluding portions of the patient's anatomy when the intravascular device500is inserted within the patient's body, and/or to better accommodate a turn within the patient's circulatory system. As non-limiting examples, in a RVAD device such as device500, the offset configuration of the inlet valve chamber514may avoid occlusion of the hepatic veins, while in a LVAD device, similar offset valve chamber(s) may avoid occlusion of, for example, the celiac artery. The offset may be flexible. The offset may be helical in configuration or it may be provided by a non-helical curve. The offset of the valve chamber514and the positioning of the intravascular device500may be configured so that the offset configuration of the valve chamber514enables the valve chamber514to be positioned radially away from, e.g., the hepatic vein in an RVAD device or the celiac artery in an LVAD device to avoid occlusion of those structures.

In the various embodiments of intravascular devices described in connection withFIGS. 1-5, the membrane chambers (e.g., membrane chambers104,204,304,404, and504) and the valve chambers (e.g., valve chambers114,322,324, and514) may be configured to be collapsible to facilitate insertion and removal from the patient's body. For example, in the embodiment ofFIG. 5, the valve chamber514may be collapsible to an overall outer diameter not substantially exceeding an outer diameter DT of the tube502. As a non-limiting example, the inlet valve chamber514may include materials such as shape memory alloys or elastic structures that can be collapsed for insertion within the body, and return to an expanded configuration once in place within the patient. Likewise, the structures of the membrane chambers104,204,304,404, and504, and the valve chambers114(FIG. 1), and322,324(FIG. 3) may similarly be configured to be collapsed to a reduced diameter compared to an expanded configuration to facilitate insertion of the intravascular devices within the patient's body. For example, the membrane chambers104,204,304,404, and504, and valve chambers114,322, and324may comprise materials such as shape memory alloys, elastic materials configured as a collapsible scaffold, framework, or mesh, or other materials and configurations.

Referring now toFIGS. 6 and 7, a device and procedure for inserting an intravascular device600within a patient's body is shown and discussed. The intravascular device600is placed within a deployment-retraction sheath636. The intravascular device600may be placed within the deployment-retraction sheath636during manufacturing, during packaging, or at another time. Various components of the intravascular device600may be configured to be placed in a collapsed configuration to facilitate insertion of the intravascular device600within the deployment-retraction sheath636. For example, as discussed above, components such as a membrane chamber (e.g., any of membrane chambers104,204,304,404, and504) and one or more valve chambers (e.g., valve chambers114,322,324, and514) may have a collapsed configuration in which they fit within the deployment-retraction sheath636as shown inFIG. 6. In the exemplary embodiment ofFIGS. 6 and 7, the intravascular device600includes a coil660comprising an elastic material positioned within a membrane chamber604in a collapsed configuration. In this collapsed configuration, the deployment retraction sheath636may be inserted within an anatomical structure (e.g., through an incision through bodily tissue) such as a femoral artery (in the case of a LVAD) or femoral vein (in the case of an RVAD). In other exemplary embodiments, depending on the configuration of the intravascular device600or needs of the patient, the intravascular device600may be inserted within the axillary, subclavian, or brachiocephalic artery or vein. In some exemplary embodiments, the deployment-retraction sheath636may include a reinforcing coil. Additional details regarding catheter structures and sheaths including similar coils can be found in U.S. Pat. No. 6,935,999, issued Aug. 30, 2017, the entire contents of which are incorporated by reference herein.

In some exemplary embodiments, prior to insertion of the deployment-retraction sheath636, a guidewire (not shown) may first be inserted and a distal end thereof positioned in the desired anatomical location, such as the pulmonary trunk for a RVAD device or the left ventricle for a LVAD device. The deployment-retraction sheath636and intravascular device600are guided along the guidewire to the desired position.

As discussed in connection withFIG. 1, in some exemplary embodiments, the intravascular device600may include markers at various positions on the device to aid a practitioner in correctly locating the device within the patient using fluoroscopic visualization. For example, in one exemplary embodiment, the valves of the device, such as inlet and/or outlet valves, may include radiopaque markers to enable the practitioner to position the valves at anatomically optimal locations, as discussed above.

Once the intravascular device is correctly located within the patient's body, the deployment-retraction sheath636is withdrawn a certain distance. Once clear of the deployment-retraction sheath636, components of the intravascular device600in a collapsed position, such as, for example, the membrane chamber604and valve chambers (e.g., valve chambers114,322,324, and514) may expand to their expanded configuration, e.g., as shown schematically inFIG. 7in dashed lines. For example, in the embodiment ofFIGS. 6 and 7, the coil660elastically expands to place the membrane chamber604in the expanded configuration shown inFIG. 7as the sheath is removed from the intravascular device600. Alternatively, the membrane chamber604and valve chamber(s) may be configured to expand upon command, such as by application of an electrical current or temperature differential to a shape-memory alloy. The deployment-retraction sheath636is withdrawn a distance sufficient to expose the valves of the intravascular device600. Accordingly, the distance the deployment-retraction sheath is withdrawn may depend at least partly on the number and position of valves of the intravascular device600.

Removal of the intravascular device600may include reversal of one or more of the insertion acts described above. For example, to remove the intravascular device600, the deployment-retraction sheath636may be advanced over the components of the intravascular device600, such as over the membrane chamber and/or valve chambers to compress the components to a diameter or size that fits within the deployment-retraction sheath636, and the deployment-retraction sheath636, with the intravascular device600positioned therein, may be withdrawn from the patient's body. When deployed, the various described membrane chambers and valve chambers possess sufficient rigidity to retain their fully deployed shapes within the patient's vasculature, which means their rigidity is sufficient to withstand intra-arterial pressures. However, these structures have may be configured to have sufficient flexibility to collapse manually when pulled through the patient's vasculature because forces exerted by the walls of more narrow blood vessels may exceed intra-arterial pressures and are sufficient to collapse these chambers as they are pulled through more distal vasculature and the access incisions through which the intravascular devices were initially inserted. Additionally, the sheath may exhibit sufficient hoop strength to cause the structures to collapse manually once pulled into the sheath.

The guidewire may be withdrawn from the patient before or after withdrawal of the deployment retraction sheath636. Depending on the configuration of the intravascular device600, the membrane balloon (e.g., membrane balloon106(FIG. 1)) and associated shaft116(FIG. 1) may have been inserted within the intravascular device600prior to insertion of the device within the patient, such as during manufacturing or packaging, or may be inserted through a hemostasis valve638once the intravascular device600is in position in the patient. For example, in an exemplary embodiment, an intravascular device without the membrane balloon106and shaft116may be inserted and positioned within the patient in the desired location to effect therapy. Once the intravascular device is in place, the membrane balloon106and shaft116are then inserted through the hemostasis valve638and advanced until the balloon106is located within the membrane chamber (e.g., membrane chamber104inFIG. 1).

The intravascular device600may be connected to a pump drive console640. The pump drive console640may provide an alternating fluid pressure through the shaft116(FIG. 1) to the membrane balloon106to alternatingly inflate and deflate the membrane balloon106as discussed above. The timing of the inflation and deflation cycles of the pump drive console640may be set manually by a practitioner based on factors such as operating characteristics of the intravascular device600and factors related to the condition and needs of the patient.

In some exemplary embodiments, the pump drive console640may include a system that controls the timing of the inflation and deflation cycles of the pump drive console640based on information received from the intravascular device600. For example, referring now toFIG. 8, the intravascular device600(FIGS. 6 and 7) may include a connector assembly such as connector portion642comprising an identification device644that is configured to provide information regarding operating characteristics of the intravascular device600to the pump drive console640(FIGS. 6 and 7). The identification device644may comprise a passive electronic component, such as a resistor or jumper wire, or may include an electronic memory component, such as a form of non-volatile memory (e.g., EEPROM). The pump drive console640may be configured to read information from the identification device644and determine an appropriate operating mode based at least in part on the information imparted by the identification device644. In some embodiments, information regarding the intravascular device600may be shared with the pump drive console using other components, such as an RFID tag on the intravascular device600and an RFID sensor of the pump drive console640.

Additionally or alternatively, the intravascular device600may be configured to provide to the pump drive console640real-time information regarding the pressure conditions within the membrane chamber (e.g., membrane chamber104(FIG. 1)). For example, referring now toFIG. 9, a right intravascular device900includes a pressure transducer946within the outlet tube908and configured to detect the pulmonary pressure. The pressure transducer946may be, for example, a fiber-optic pressure transducer utilizing an optical cavity that changes in response to applied pressure or other optical configurations and/or components. Pressure information obtained from the pressure transducer946may be transmitted to the pump drive console640(FIGS. 6 and 7) through the connector portion642when the connector portion642is coupled with a complementary connector on the pump drive console640. Additionally, or alternatively, blood pressure measurements can be made using a side port (not shown) of the deployment-retraction sheath636(FIGS. 6 and 7). Blood pressure may be measured, for example, in the superior vena cava (the in case of a RVAD) or the aorta (in the case of a LVAD). While the pressure transducer946is shown within the outlet tube908, in exemplary embodiments, one or more pressure transducers may be included adjacent to intake valves and/or outlet valves, such as adjacent inlet valves112(FIG. 1) and outlet valve110(FIG. 1).

Information regarding the pressure within the membrane balloon (e.g., membrane balloon106inFIG. 1) may be used to control the operation of the pump drive console640. For example, the pressure within the membrane balloon106may be detected by a pressure transducer within the pump drive console640, or by a pressure transducer similar to pressure transducer946(FIG. 9) located within the membrane balloon106itself.

In an exemplary embodiment, the pump drive console640may control various operational characteristics such as, for example, timing of inflation and deflation events based on the pressure in the membrane balloon106. For example, based on the pressure waveform of the membrane balloon, the pump drive console640can detect when the membrane balloon106is completely deflated, and immediately switch to inflation to re-inflate the membrane balloon106. Additionally, or alternatively, the pump drive console640can detect when the pressure within the membrane balloon106has reached a plateau, and immediately begin deflating the membrane balloon106.

In some exemplary embodiments, a time delay between deflation and inflation may be utilized to enhance filling and evacuation of the membrane chamber104(FIG.1). For example, assuming the membrane chamber is not a perfectly rigid structure, blood flow into the membrane chamber104may be such that the membrane chamber104does not fill as quickly as the membrane balloon106deflates, a dwell time at maximal deflation may be used to ensure the membrane chamber104fills completely with blood. Similarly, in some embodiments, a dwell time at maximum inflation is used to ensure complete evacuation of the membrane chamber104. Such dwell times may be equal or unequal based on, for example, unequal flow resistances into and out of the membrane chamber104, and may be based on the characteristics of the intravascular device, anatomical conditions, or both.

Additionally, or alternatively, in some exemplary embodiments, the pressure of either the membrane chamber104or the membrane balloon106may be monitored by the pump drive console640and a change in pressure over time may be used to control inflation or deflation of the membrane balloon106. For example, the change in pressure over time (dP/dt) is monitored, and when this value approaches zero the blood flow into or out of the membrane chamber104is minimal. The pump drive console640can use this pressure information to minimize dwell times at the inflated and deflated state, subject to the additional considerations noted above regarding the potential need for lengthened dwell times.

Additional aspects of the operation of the pump drive console640may be based on various factors relating to characteristics of the intravascular devices according to exemplary embodiments of the present disclosure. For example, the pump drive console640may include a manual setting mode which allows a practitioner to manually set timing of the inflation-deflation cycles including dwell times. Such a manual mode could also enable a practitioner to configure the pump drive console640to operate in a co-pulsation mode, in which the intravascular device provides pumping action in phase with the beating of the patient's heart, or a counter-pulsation mode, in which the intravascular device provides pumping action out of phase with the beating of the patient's heart. Signals representative of the action of the patient's heart may be obtained through, for example, an electrocardiogram (EKG) signal or other heart activity monitoring signal, such as a pressure signal from the pulmonary artery. In some embodiments, the pump console640may be configured to detect the heart activity and supplement action of the heart as necessary to maintain a particular flow rate. In other words, if the patient's heart activity is relatively weak, the pump console640will drive the intravascular device600to provide a relatively higher supplemental flow rate than if the patient's heart activity were relatively stronger. Additionally, certain functions of the pump drive console640, such as alarms or alarm settings based on pressure conditions, user interface settings, or other settings can be optimized for use with intravascular devices according to the present disclosure.

Additionally, the inflation/deflation cycles of the pump console640may be asynchronous with the pulsation of the patient's heart. While the pulsatile nature of the pumping action of the intravascular device600is noted above, various aspects of the intravascular device600may be altered to provide a flow with a waveform closer to continuous flow. For example, the size and configuration of the valves and tubes of the intravascular device600may influence the flow from the intravascular device600and approximate a more consistent flow rate. As an additional example, the volume of the membrane chamber104(FIG. 1) and the membrane balloon106(FIG. 1) may be changed to alter the pumping characteristics of the intravascular device. For example, if the volume or displacement of the membrane balloon106is reduced, each inflation/deflation cycle of the balloon106pumps a smaller volume of blood. To compensate and provide the same flow rate as a device with a relatively larger membrane balloon106, the cycle time of a complete inflation/deflation cycle may be reduced. Thus, smaller, more frequent pulses will be delivered by the intravascular device, and the smaller, more frequent pulses may more closely approximate a continuous flow from a physiological perspective. In such a system, when used in the right heart, it is not necessary to pace with the native heart rate. In addition, in the right heart, the cycling can be asynchronous.

As a non-limiting example of device sizes, a membrane balloon for use in an adult using a co-pulsation (in phase) mode, counter-pulsation (out of phase by a predetermined degree) mode, or asynchronous cycle (i.e., phase shift between the heart and the pumping membrane varies with time; an asynchronous cycle may, for example, cycle the device at a rate other than the native heart rate or may cycle the device at the patient's heart rate but with a timing that is neither co-pulsation or counter-pulsation but rather somewhere between them) may have a displacement ranging from about 25 cubic centimeters (cc) to about 50 cc per cycle. To provide smaller, more frequent flow pulses, the displacement of the membrane balloon may be reduced by, for example, 50% or more, and the cycle time of a full inflation/deflation cycle may be reduced by a corresponding (e.g., a proportional) amount. In this way, the amount of supplemented blood flow provided by the intravascular device in combination with the patient's own cardiac output maintains systemic blood flow substantially at a desired physiologic target range, although when using a smaller pumping membrane then higher rates of cycling are required to achieve the same degree of blood flow supplementation as may be achieved by a larger pumping membrane cycling at a slower rate. In one example embodiment, the balloon membrane may have a volume ranging from about 5 cc to about 20 cc, and the cycle time is reduced from a typical co- or counter-pulsation cycle and ranges, for example, from about 40% to about 90% less.

In one exemplary embodiment, the cycling rate may be generally inversely proportional to a volume of the inflatable membrane. As will be understood by those of skill in the art, variables such as the filling and emptying time of the membrane chamber would impact this proportionality.

In addition, the length and diameter of the membrane balloon may be changed while keeping the volume of the membrane balloon constant to enable, for example, use of a relatively longer, narrower membrane chamber, which may improve blood flow around the device. Moreover, multiple membrane balloons within a single membrane chamber, or multiple chambers each with one or more respective balloons, may be used.

In accordance with one aspect of the present disclosure, connection of the connector assembly, e.g., connector portion642with identification device644to the pump console may cause the pump console to automatically switch between operational modes, for example, from a first general operational mode to a second operational mode specific to intravascular devices. In such an embodiment, when switching to the second operational mode, the pump console may display operational settings associated with the intravascular device. Examples of such operational settings include, but are not limited to, alarm settings, detection settings, alarm conditions, device cycle triggering, device cycle timing, and user interface settings.

Referring now toFIG. 10, an intravascular device1000according to an exemplary embodiment is shown positioned within a schematic drawing of an arterial structure1048of a patient's left heart and aorta. This exemplary embodiment may be characterized as a left heart intravascular device. The intravascular device1000includes a membrane chamber1004within which a membrane balloon1006is disposed. The intravascular device1000includes a one-way inlet valve1012positioned at a distal end of a distal tube1008. A distal end of the distal tube1008extends into the patient's left ventricle1050. Outlet valves1010are disposed in valve chambers1022and1024positioned distal to and proximal to the membrane chamber1004, respectively. The valve chamber1024is positioned along a tube1002and is located a distance dv from the membrane chamber1004. The distance dv may be chosen such that the valve chamber1024and the associated outlet valve1010is located adjacent to a renal artery1052. Such positioning of the valve chamber1024may facilitate perfusion of blood expelled from the outlet valve1010into the renal artery1052. Positioning the valve chamber1024adjacent the renal artery1052may be facilitated by, e.g., radiopaque markers such as radiopaque markers117(FIG. 1).

The location of the valve chamber1022distal to the chamber1004may be chosen such that the valve chamber1022is positioned adjacent one or more of the brachiocephalic artery1054, the left common carotid artery1056, and the left subclavian artery1058. Stated differently, when the distal end of the distal tube1008is positioned in a target position (e.g., within the left ventricle1050), one outlet valve1010is positioned adjacent the arteries in the aortic arch (e.g., the brachiocephalic artery1054, the left common carotid artery1056, and the left subclavian artery1058), while the other outlet valve1010is positioned adjacent the renal arteries1052. Positioning the valve chamber1022adjacent, e.g., the common carotid arteries, may facilitate cerebral perfusion of blood expelled from the outlet valve1010associated with the valve chamber1022. Positioning of the valve chamber1022may be facilitated by radiopaque markers, such as radiopaque markers117(FIG. 1). In some exemplary embodiments, the valve chamber1022may be positioned closer to the distal end of the distal tube1008than the position shown inFIG. 11, and the direction of the outlet valve1010may be reversed to direct blood flow toward the brachiocephalic artery1054, the left common carotid artery1056, and the left subclavian artery1058.

Referring now toFIG. 11, an intravascular device1100according to another embodiment of the disclosure is shown positioned within a venous structure of a patient, such as a portion of the patient's right heart1160and inferior vena cava. This exemplary embodiment may be characterized as a right heart intravascular device. The intravascular device1100includes a membrane chamber1104within which is positioned a membrane balloon1106. A distal tube1108with a one-way outlet valve1110extends distally from the membrane chamber1104. In the embodiment ofFIG. 11, the membrane chamber1104is positioned within the inferior vena cava (IVC)1162. However, as non-liming examples of alternative configurations, the present disclosure contemplates positioning the membrane chamber1104within the superior vena cava1164, the right atrium1166, or the right ventricle1168. To facilitate such positioning, configurations of the intravascular device1100may feature different shapes and sizes of the membrane chamber1104, different lengths of the distal tube1108, etc. In the embodiment ofFIG. 11, the distal tube1108extends from the membrane chamber1104in the IVC, through the right atrium1166and past the tricuspid valve1170, through the left ventricle1168and past the pulmonary valve1172and into the pulmonary artery1174.

The intravascular device1100includes an inlet valve1112positioned in an inlet valve chamber1114. The inlet valve chamber1114is positioned proximal to the membrane chamber1104, and the position of the inlet valve chamber1114may be chosen to locate the inlet valve1112proximate a venous structure of the patient, such as renal veins1176. In addition, in the exemplary embodiment ofFIG. 11, an additional inlet valve1112may be positioned on the membrane chamber1104, and the additional inlet valve1112may be located proximal another venous structure of the patient, such as a hepatic vein1178.

Stated another way, the device1100may be configured such that when the distal tube1108is positioned within a target position within the pulmonary artery1174, the inlet valves1112may be positioned adjacent anatomical structures such as, for example, the hepatic vein1178, one or more renal veins (not shown), or other anatomical structures.

The procedures discussed above with regard toFIGS. 10 and 11are not necessarily exclusive of one another. That is, it is possible to use a left heart intravascular device and a right heart intravascular device, as described and embodied herein, together to provide bi-ventricular support. Thus, a system for providing bi-ventricular support may include both left and right heart intravascular devices. The system may be used with a single pump console or two pump consoles.

FIGS. 12A and 12Billustrate an exemplary embodiment of an expanding chamber1204of an intravascular device1200. In the embodiment ofFIG. 12A, the chamber1204includes a mesh structure1280, and the chamber1204and mesh structure1280are compressed within an insertion/retraction sheath1236that is inserted within a blood vessel1282of a patient. A membrane balloon1206within the chamber1204is in a deflated state inFIG. 12A. Once the chamber1204is advanced to the desired location, the insertion/retraction sheath1236is withdrawn as discussed in connection withFIGS. 6 and 7, and the mesh structure1280expands the chamber within the blood vessel1282, as shown inFIG. 12B. The mesh structure1280may comprise, without limitation, elastic materials such as metals or polymers, shape memory materials such as metals or polymers, composite materials, or other materials, as discussed above. Once the chamber1204is expanded, the balloon membrane1206may be cyclically inflated and deflated to provide pumping action as discussed generally in the embodiments above.

Ventricular-assist devices according to the present disclosure provide advantages over previous devices. For example, intravascular devices according to the disclosure provide improved interactions with a patient's anatomy, such as avoiding occlusion of the valves of the intravascular devices by anatomical structures, and positioning the valves of the device in chosen areas to improve perfusion of blood expelled from the intravascular device. Additionally, pump drive consoles according to embodiments of the disclosure feature operating configurations and algorithms that enhance (e.g., maximize) effectiveness of intravascular devices.

It is to be understood that the particular examples and embodiments set forth herein are non-limiting, and modifications to structure, dimensions, materials, and methodologies may be made without departing from the scope of the present teachings. While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Any combination of the above embodiments is also envisioned and is within the scope of the appended claims. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.