BACKGROUND

Ventricular assist devices, known as VADs, often include an implantable blood pump and are used for both short-term (i.e., days, months) and long-term applications (i.e., years or a lifetime) where a patient's heart is incapable of providing adequate circulation, commonly referred to as heart failure or congestive heart failure. According to the American Heart Association, more than five million Americans are living with heart failure, with about 670,000 new cases diagnosed every year. People with heart failure often have shortness of breath and fatigue. Years of living with blocked arteries and/or high blood pressure can leave a heart too weak to pump enough blood to the body. As symptoms worsen, advanced heart failure develops.

A patient suffering from heart failure may use a VAD while awaiting a heart transplant or as a long term destination therapy. A patient may also use a VAD while recovering from heart surgery. Thus, a VAD can supplement a weak heart (i.e., partial support) or can effectively replace the natural heart's function.

In many instances, blood from a ventricle of the heart is extracted through an aperture or opening formed in the wall of the ventricle and pumped by a VAD to the patient's circulatory system. For example, a left ventricular assist device (LVAD) can extract blood from the patient's left ventricle and pump the blood into the patient's ascending aorta. A VAD can be implanted adjacent to the heart, in contact with the heart, or in a remote location such as the abdomen. Existing approaches for fluidly coupling a VAD with the heart include removing a portion of the heart wall via coring or cutting to create an opening, suturing an annular cuff to the exterior of the heart wall opening, and aligning the VAD with the annular cuff. The cuff attachment procedure however is substantially invasive, both in terms of the amount of access required and the localized trauma inflicted on the heart wall, and can be a time consuming and complicated procedure that is costly. As such, improved methods and devices for VAD implantation may be desirable.

BRIEF SUMMARY

Improved implantable structures and methods for fluidly coupling a VAD with a ventricle, and related surgical assemblies and methods, are described. In many embodiments, a distal end of a delivery device is penetrated through a ventricular wall through an aperture into a ventricle. A self-expandable coupler, such as an anchor, stent, scaffold, shunt, or other expandable structure, is deployed from the delivery device to engage the aperture and form an access conduit for extraction of blood from the ventricle. The delivery device is then removed via the aperture, leaving the coupler attached to the heart wall. An inlet fluid channel for the VAD can then be coupled with the coupler to place the VAD in fluid communication with the ventricular chamber via the coupler conduit. In contrast with existing approaches that require substantial access to the heart and induce substantial localized trauma to the heart via associated coring, cutting, and/or suturing, the implantation of a self-expandable coupler via a delivery device as described herein can be accomplished faster, simpler, and less invasively with reduced access to the heart. The procedure may result in a smaller ventricle aperture (defect) that is dilated so as to minimize localized trauma to the heart wall. Further, the expandable structure of the coupler allows accommodation in a variety of VAD inlet conduit sizes and shapes as well as varying aperture diameters.

Thus, in one aspect, a method of implanting a ventricular assist device in a patient is provided. The method includes penetrating a distal end of a delivery device through a wall of a heart into a ventricle of the heart through an aperture having a diameter in the wall. Penetrating may comprise dilating the aperture with the delivery device, such as a catheter, so as to expand the diameter of the aperture while minimizing complications such as excessive blood leakage or unintended damage to adjacent structures or vessels. An expandable coupler is deployed from the delivery device so that the coupler engages the aperture and forms a conduit for a flow of blood from the ventricle. The delivery device is removed from the ventricle by retracting the delivery device through the aperture. The ventricular assist device is coupled to the coupler to receive the flow of blood from the ventricle and pump the flow of blood to assist circulation in the patient.

In many embodiments of the method, the coupler engages an inner surface of the heart wall adjacent to the aperture and/or an outer surface of the heart wall adjacent to the aperture. For example, the method of implanting a ventricular assist device in a patient can include (a) engaging an inner surface of the wall of the heart with an inner flange of the coupler that protrudes radially relative to the aperture, and/or (b) engaging an outer surface of the wall of the heart with an outer flange of the coupler that protrudes radially relative to the aperture. Methods include accommodating ingrowth of tissue from the heart wall into the coupler. For example, the method can include accommodating ingrowth of tissue from at least one of (a) the inner surface of the wall into the inner flange of the coupler, (b) the outer surface of the wall into the outer flange of the coupler, and/or (c) a surface of the aperture of the wall into a portion of the coupler engaged with the aperture. Tissue ingrowth into the coupler can provide for a natural blood contact surface and compressive seal barrier that further minimizes blood leakage as well as clot or thrombus formation.

Deploying the self-expanding coupler from the delivery device can include reconfiguring the delivery device to release the coupler from a delivery configuration so that the coupler self-expands to a deployed configuration. Any suitable approach can be used to release the coupler. For example, reconfiguring the delivery device to release the coupler from the delivery configuration can include retracting a sheath from a retention configuration in which the sheath retains the coupler in the delivery configuration to a release configuration in which the coupler is not retained by the sheath.

In many embodiments of the method, the coupler is partially released so that an inner flange of the coupler is expanded within the ventricle and then retracted to bring the inner flange into engagement with the ventricular wall prior to release of the rest of the coupler. For example, reconfiguring the delivery device to release the coupler from the delivery configuration can include retracting the sheath from the retention configuration to an inner flange release configuration in which the inner flange of the coupler protrudes radially from the delivery device and a portion of the coupler is retained by the sheath. Deploying the coupler from the delivery device can include retracting the delivery device with the sheath in the inner flange release configuration to bring the inner flange into engagement with the inner surface of the wall of the heart.

In many embodiments of the method, the coupler can be configured to block flow of blood through the aperture prior to coupling of the VAD with the coupler. For example, the coupler can include a flow control portion reconfigurable from a flow blocking configuration to a flow accommodating configuration. The method can further include (a) blocking flow of blood through the conduit via the flow control portion in the flow blocking configuration prior to coupling the ventricular assist device to the coupler, and (b) reconfiguring the flow control portion from the flow blocking configuration to the flow accommodating configuration to accommodate the flow of blood from the ventricle to the ventricular assist device for pumping to assist circulation in the patient. Any suitable approach can be used to reconfigure the flow control portion from the flow blocking configuration to the flow accommodating configuration. For example, reconfiguring the flow control portion from the flow blocking configuration to the flow accommodating configuration can include engaging an inlet conduit of the ventricular assist device with the flow control portion to deform the flow control portion from the flow blocking configuration to the flow accommodating configuration.

Any suitable approach can be used to fluidly couple the VAD with the ventricle via the coupler. For example, coupling the ventricular assist device to the coupler can include inserting an inlet conduit of the ventricular assist device into the conduit of the coupler so that inlet conduit forms a sealed attachment with the coupler. The coupler has an inlet portion that extends into the ventricle. The inlet portion that extends into the ventricle can have any suitable configuration (e.g., geometry, shape, size, etc.). For example, a portion of the conduit formed by the inlet portion can have a tapering cross-sectional area. The inlet portion can have an inlet edge shaped to form one or more valleys between adjacent peaks. The one of more valleys can be configured to maintain fluid communication between the ventricle and the conduit if contact occurs between the inlet edge and an inner surface of the ventricle. The inlet portion can have one or more features that interface with the coupler and accommodate insertion of the inlet portion into the conduit of the coupler and prevent extraction of the inlet portion from the conduit of the coupler without the application of significant extraction force to the inlet portion. For example, the inlet portion can include a one-way locking catch and/or hook structure that that interfaces with the coupler and accommodates insertion of the inlet portion into the conduit of the coupler and prevents extraction of the inlet portion from the conduit of the coupler without the application of significant extraction force to the inlet portion. Advantageously, the aperture or puncture diameter is smaller than the inlet portion of the coupler in the deployed configuration for a less invasive procedure and larger opening inlet.

In another aspect, a surgical assembly for coupling a ventricular assist device with a ventricle of a heart of a patient is disclosed. The surgical assembly includes a self-expandable implantable coupler and a delivery device for implanting the coupler. The implantable coupler is reconfigurable between a delivery configuration and a deployed configuration. The coupler is configured to expand from the delivery configuration to engage an aperture through a wall of the ventricle and form a conduit for a flow of blood from the ventricle. The coupler is further configured to couple with a ventricular assist device to transfer the flow of blood to the ventricular assist device for pumping to assist in circulation of the patient. The delivery device is configured for implanting the coupler. The delivery device includes a distal end portion shaped for penetration through the wall of the ventricle to form the aperture and a repositionable sheath having a retention configuration in which the sheath retains the coupler in the delivery configuration and a release configuration accommodating release of the coupler via self-expansion of the coupler from the delivery configuration to the deployed configuration. The delivery device may comprise a catheter configured to dilate the aperture so as to expand a diameter of the aperture.

In many embodiments of the surgical assembly, the coupler is configured to interface with the heart wall adjacent to the aperture. For example, in many embodiments, the coupler has (a) an inner flange that protrudes radially relative to the aperture and is configured to interface with an inner surface of the wall of the ventricle, and/or (b) an outer flange that protrudes radially relative to the aperture and is configured to interface with an outer surface of the wall of the ventricle. The outer and/or inner flange can have any suitable configuration. For example, the shape of the outer and/or inner flange may further inhibit mal-positioning of the inlet portion. The coupler is configured to accommodate ingrowth of tissue from the heart wall. For example, the coupler can include one or more material layers configured to accommodate ingrowth of tissue from at least one of (a) the inner surface of the wall into a portion of the material layer disposed in the inner flange of the coupler, (b) the outer surface of the wall into a portion of the material layer disposed in the outer flange of the coupler, and/or (c) a surface of the aperture in the wall into a portion of the material layer disposed in a portion of the coupler engaged with the aperture. Additionally, at least one anchor may be provided on the outer flange to further facilitate coupler engagement with the wall the ventricle.

In many embodiments, the surgical assembly is configured to partially deploy the coupler to deploy an inner flange of the coupler within the ventricle for subsequent retraction into engagement with the heart wall prior to deployment of the rest of the coupler. For example, in many embodiments of the surgical assembly, the repositionable sheath has an inner flange release configuration in which the inner flange of the coupler outwardly protrudes from the delivery device and a portion of the coupler is constrained by the repositionable sheath to enable deployment of the inner flange within the ventricle and subsequent retraction of the delivery device to bring the inner flange into engagement with the inner surface of the wall of the ventricle prior to deployment of the rest of the coupler.

In many embodiments of the surgical assembly, the coupler is configured to block flow of blood through the coupler conduit prior to coupling a VAD with the coupler. For example, in many embodiments, the coupler includes a flow control portion reconfigurable from a flow blocking configuration that blocks flow of blood through the conduit prior to coupling of the ventricular assist device to the coupler to a flow accommodating configuration that accommodates the flow of blood from the ventricle to the ventricular assist device for pumping to assist circulation in the patient. The flow control portion can be reconfigurable from the flow blocking configuration to the flow accommodating configuration via engagement of an inlet conduit of a ventricular assist device with the flow control portion to reconfigure the flow control portion. The flow control portion can have any suitable configuration. For example, the flow control portion may comprise a membrane or valve member.

The coupler included in the surgical assembly can have any suitable configuration for fluidly coupling the VAD with the ventricle. For example, the coupler can be configured for insertion of an inlet conduit of the VAD into the conduit of the coupler so that a sealed attachment is formed between the inlet conduit of the VAD and the coupler. In many embodiments of the surgical assembly, the coupler has an inlet portion configured to extend into the ventricle. The inlet portion that extends into the ventricle can have any suitable configuration. For example, a portion of the conduit formed by the inlet portion can have a tapering cross-sectional area. The inlet portion can have an inlet edge shaped to form one or more valleys between adjacent peaks. The one of more valleys can be configured to maintain fluid communication between the ventricle and the conduit if contact occurs between the inlet edge and an inner surface of the ventricle. The inlet portion can have one or more features that interface with the coupler and accommodate insertion of the inlet portion into the conduit of the coupler and prevent extraction of the inlet portion from the conduit of the coupler without the application of significant extraction force to the inlet portion. For example, the inlet portion can include a one-way locking catch and/or hook structure that that interfaces with the coupler and accommodates insertion of the inlet portion into the conduit of the coupler and prevents extraction of the inlet portion from the conduit of the coupler without the application of significant extraction force to the inlet portion. Minimally invasive catheter delivery and the self-expanding structure of the coupler allows for the diameter of the aperture to be smaller than a diameter of the inlet edge of the coupler inlet portion in the deployed configuration. The inlet portion of the coupler may form a funnel or cone shape having a variable angle opening (e.g., wide funnel) or any other suitable shape, size, or angle orientation.

The coupler included in the surgical assembly can further comprise a mesh or coating layer supported by the frame (e.g., coupled to an inner or outer surface of the frame). The mesh layer or coating may accommodate ingrowth of tissue into the coupler to create a natural tissue interface that provides improved sealing with the aperture and reduces any blood leakage. The coupler may additionally or alternatively include a rigid or semi-flexible support section in a portion of the conduit that extends within the aperture in the wall of the ventricle. This rigid support, tube, or bore may be integral with the coupler or an additional structural support so that the coupler has sufficient rigidity to prevent collapse of the coupler and maintain patency and access.

In another aspect, an implantable coupler for coupling a ventricular assist device with a ventricle of a heart of a patient is disclosed. The implantable coupler includes a self-expandable frame, such as a woven nickel titanium tube, and a material layer, such as a polyester mesh, that accommodates tissue ingrowth (e.g., endothelialization) from the heart wall for stabilization. The frame is configured to expand from a collapsed configuration sized to be inserted through an aperture in a wall of the ventricle to a deployed configuration in which the frame (a) engages the aperture, (b) expands or dilates the aperture, (c) forms a conduit for a flow of blood from the ventricle, (d) forms an inner flange that protrudes radially relative to the aperture and is configured to interface with an inner surface of the wall of the ventricle, and (e) forms an outer flange that protrudes radially relative to the aperture and is configured to interface with an outer surface of the wall of the ventricle. The material layer is supported by the frame and accommodates ingrowth of tissue into the material layer from at least one of (a) the inner surface of the wall of the ventricle into a portion of the material layer disposed in the inner flange of the coupler, (b) the outer surface of the wall of the ventricle into a portion of the material layer disposed in the outer flange of the coupler, and/or (c) a surface of the aperture in the wall of the ventricle into a portion of the material layer disposed in a portion of the coupler engaged with the aperture.

In many embodiments, the implantable coupler is configured to block flow of blood through the coupler conduit prior to coupling a VAD with the coupler. For example, the implantable coupler can include a flow control portion reconfigurable from a flow blocking configuration that blocks flow of blood through the conduit prior to coupling of the ventricular assist device to the coupler to a flow accommodating configuration that accommodates the flow of blood from the ventricle to the ventricular assist device for pumping to assist circulation in the patient. The flow control portion can have any suitable configuration. For example, the flow control portion can be reconfigurable from the flow blocking configuration to the flow accommodating configuration via engagement of an inlet conduit of the ventricular assist device with the flow control portion to reconfigure the flow control portion.

The implantable coupler can have any suitable configuration for fluidly coupling the VAD with the ventricle. For example, the coupler can be configured for insertion of an inlet conduit of the ventricular assist device into the conduit of the coupler so that a sealed attachment is formed between the inlet conduit and the coupler. In many embodiments, the implantable coupler has an inlet portion configured to extend into the ventricle. The inlet portion that extends into the ventricle can have any suitable configuration. For example, a portion of the conduit formed by the inlet portion can have a tapering cross-sectional area forming a funnel shape in the deployed configuration. The inlet portion can have an inlet edge shaped to form one or more valleys between adjacent peaks. The one of more valleys can be configured to maintain fluid communication between the ventricle and the conduit if contact occurs between the inlet edge and an inner surface of the ventricle. The inlet portion can have one or more features that interface with the coupler and accommodate insertion of the inlet portion into the conduit of the coupler and prevent extraction of the inlet portion from the conduit of the coupler without the application of significant extraction force to the inlet portion. For example, the inlet portion can include a one-way locking catch and/or hook structure that that interfaces with the coupler and accommodates insertion of the inlet portion into the conduit of the coupler and prevents extraction of the inlet portion from the conduit of the coupler without the application of significant extraction force to the inlet portion.

The above presents a simplified summary of some embodiments of the invention in order to provide a basic understanding of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some embodiments of the invention in a simplified form as a prelude to the more detailed description that is presented later. For a fuller understanding of the nature and advantages of the present invention, reference should be made to the ensuing detailed description and accompanying drawings.

