CN115430036A - Ventricular assist device with diastolic function - Google Patents

Abstract

The invention discloses a ventricular assist device with a diastolic function, which comprises a flexible air bag attached to a heart, wherein the top of the flexible air bag is provided with an opening, and a pneumatic lock is arranged at the top of the flexible air bag; the flexible air bag is formed by two layers of biocompatible films, the biocompatible films extend upwards for a section to form the pneumatic lock which is in contact with the heart, and a locking structure is formed between the pneumatic lock and the heart, so that free air does not exist between the flexible air bag and the heart; one or more gas chambers are formed between the inner film and the outer film below the pneumatic lock, and the gas inlet and the gas outlet are respectively connected with each gas chamber; the ventricular assist device has an elastic energy storage element, which is a frame made of a shape memory alloy or a polymer, disposed on the outer membrane of the flexible balloon. The flexible balloon of the device inflates during systole to create a positive pressure and deflates during diastole without reversing or significantly disrupting the curvature of the heart, thereby assisting diastole.

Description

A ventricular assist device with diastolic function

technical field

The invention relates to a ventricular assist device with a diastolic function, which belongs to the technical field of medical instruments.

Background technique

Heart failure is a major public health problem in both developed and developing countries. There are two main forms of heart failure: systolic insufficiency and diastolic insufficiency. In systolic dysfunction, the heart contracts less forcefully and cannot pump as much blood as it normally would. When diastolic dysfunction occurs, the heart becomes stiff and cannot relax normally after contraction, the ability of the heart to congest is reduced, and the congestion is insufficient. Although systolic heart failure is better known, heart failure caused by abnormal diastolic function also increases cardiac morbidity and mortality.

Because heart transplants, although effective, are in short supply, people think of using artificial hearts or mechanical assist devices to keep patients with heart failure alive. Classified according to the working form, ventricular assist devices can be divided into two types: blood-contacting and non-blood-contacting. Most of the blood-contacting devices are pumps. Due to the direct contact between blood and equipment, it will damage the blood and cause hemolysis and thrombosis. It also requires open chest surgery and surgery on the heart. The principle of non-blood contact is that the device directly wraps the heart, and then controls its contraction synchronously with the natural heart to improve heart function, increase the pumping volume, and will not directly contact with blood, but the traditional non-blood contact device will suffer from extrusion Causes a reverse curvature of the heart.

Figures 1A-1C show normal, zero, and inverted curvatures of the heart in a radial plane (major axis) from apex to base. Figure 1A shows normal or positive curvature inside the chamber, 1B zero curvature, and 1C inverse or negative curvature.

Reflex curvature can greatly increase the ejection rate of blood. However, the ventricular curvature of a normal heart does not exhibit inverse curvature. Conventional direct-heart-contact devices focus on increasing systolic capacity rather than diastolic function, inverting the curvature of the heart. Furthermore, none of the conventional devices are implanted in a minimally invasive manner, requiring open chest surgery, and most conventional devices require suturing the device to the heart or pericardium.

Contents of the invention

The object of the present invention is to provide a ventricular assist device with a diastolic function, which focuses on enhancing the diastolic ability of the damaged or diseased heart, and has the function of assisting the diastole of the heart.

To achieve the above object, the present invention adopts the following technical solutions:

A ventricular assist device with a diastolic function, the device includes a flexible air bag that fits the heart, the top of the flexible air bag is open, and there is a pneumatic lock at the top position;

The flexible airbag is formed by two layers of biocompatible film, and the biocompatible film extends upward for a section to form the pneumatic lock in contact with the heart, and a locking structure is formed between the pneumatic lock and the heart, so that the flexible airbag is in contact with the heart. There is no free air between the hearts;

Below the pneumatic lock, one or more gas chambers are formed between the inner membrane and the outer membrane, and the gas inlet and outlet are respectively connected to each gas chamber;

The ventricular assist device has an elastic energy storage element disposed on the adventitia of a flexible balloon, the elastic energy storage element being a frame made of a shape memory alloy or polymer; the elasticity is utilized when the heart pressure is below the end-diastolic pressure The energy storage element creates a negative pressure that promotes ventricular filling, and the elastic energy storage element acts to limit filling when the cardiac pressure exceeds the end-diastolic volume.

The inner membrane of the flexible balloon has folds, and the gas chamber expands mostly inwardly to contact the epicardium of the heart when inflated.

The gas chamber is a longitudinally oriented chamber when inflated, and the gas chamber is collapsible when deflated.

The opening at the top of the flexible airbag is small, and the pneumatic lock forms a locking structure by clamping the heart or wrapping the heart.

The bottom of the ventricular assist device has access openings for aspiration of fluid that may be present between the heart and the device.

The outside of the ventricular assist device is covered with a film made of biomedical materials.

Beneficial effects of the present invention:

The flexible balloon of the ventricular assist device of the present invention inflates and creates a positive pressure during systole and deflates during diastole without inverting or significantly disturbing the curvature of the heart, thereby assisting diastole.

The ventricular assist device of the present invention can be implanted quickly and minimally invasively, and does not need to be sutured or directly connected to the heart, but is connected to the heart through pneumatic locking, with minimal damage to the heart.

Description of drawings

Figures 1A-1C show normal, zero, and inverted curvatures of the heart in a radial plane (major axis) from apex to base.

Fig. 2 shows a schematic cross-sectional front view of a ventricular assist device according to an embodiment of the present invention installed on the heart in a deflated state for assisting relaxation.

Fig. 3 shows a schematic cross-sectional front view of a ventricular assist device according to an embodiment of the present invention installed on the heart and in an inflated state assisting contraction.

Fig. 4 shows a schematic cross-sectional front view of a ventricular assist device according to another embodiment of the present invention installed on the heart in a deflated state for assisting relaxation.

Fig. 5 shows a schematic cross-sectional front view of a ventricular assist device according to another embodiment of the present invention installed on the heart in an inflated state to assist contraction.

Fig. 6 is a top view of a heart assist device of the present invention.

Fig. 7 is a front view of a heart assist device of the present invention.

Fig. 8 is a schematic diagram of the connection between the heart assist device and the extracorporeal air circuit assembly of the present invention.

detailed description

Embodiments of the present invention will be described below based on the drawings.

The ventricle assisting device of the present invention has the function of assisting heart diastole. As a specific embodiment of the present invention, as shown in Figures 2 and 3, the device includes a flexible airbag 1 that fits the heart, the top of the flexible airbag 1 is open, and has a pneumatic lock 2 at the top position; Formed by two layers of biocompatible membranes (including inner membrane 3 and outer membrane 4), the biocompatible membrane extends upward for a section to form the pneumatic lock 2 in contact with the heart, between the pneumatic lock 2 and the heart A closed structure is formed so that there is no free air between the flexible balloon and the heart. As shown in Figure 3, under the pneumatic lock 2, one or more gas chambers 5 are formed between the inner membrane and the outer membrane, and the gas inlet and outlet (not shown) are respectively connected with each gas chamber. 5 connected; the ventricular assist device has an elastic energy storage element 6 arranged on the adventitia of the flexible balloon, and the elastic energy storage element is a frame made of shape memory alloy or polymer; when the heart pressure is lower than the end-diastolic pressure When using the elastic energy storage element to generate negative pressure to promote ventricular filling, when the heart pressure exceeds the end-diastolic volume, the elastic energy storage element plays a role in limiting filling.

In the ventricular assist device of the present invention, the top opening of the flexible air bag is small, and the pneumatic lock forms a closed structure by clamping the heart or wrapping the heart, and has good sealing performance. As shown in Figures 2 to 5, the opening of the flexible airbag 1 becomes smaller as it goes upwards, which helps to fit the heart completely. A circle extending from the top of the airbag is a pneumatic lock. The shape and size of the pneumatic lock can be adjusted according to the heart size of different patients. It is specially made to achieve the purpose of perfectly fitting the heart. The purpose of the pneumatic lock is to completely fit the heart to form an internal closed structure, that is, there is no free air. If the pneumatic lock does not fit the heart, it may cause air leakage and fail to form a closed structure.

Due to the setting of the pneumatic lock, there is no free air in the space between the flexible balloon and the heart during use, so if the heart becomes smaller (due to ejecting blood), the flexible balloon will be pulled inward. Likewise, when the flexible balloon expands outward, it acts like a suction cup to exert traction on the heart. If there is free air in the chest cavity (which usually isn't), suction traction draws air between the flexible balloon and the heart. However, due to the setting of the pneumatic lock, there is no free air between the flexible balloon and the heart, and the attracting traction force acts directly on the surface of the heart. Because the elastic energy storage element has a memory function, when the heart pressure exceeds the end-diastolic volume, it will give a pressure to limit the relaxation; when the heart pressure is lower than the end-diastolic volume, because there is no free air, it will give the heart a dilation through pneumatic locking The force that assists the relaxation of the heart.

The ventricular assist device of the present invention selectively compresses the heart during systole, and during diastole, gas exits the gas chamber through the gas outlet to pull apart the biocompatible inner membrane of the pneumatic lock and pull the heart apart to Optionally helps fill the heart. The ventricular assist device of the present invention can apply non-uniform pressure or uniform pressure to the surface of the heart to alter the end-systolic structure of the heart, the end-diastolic structure of the heart, or both. The ventricular assist device of the present invention can provide different diastolic assistance to different ventricles through uniform or uneven inflation and deflation according to the lesion degree and diastolic requirements of each ventricle, and uniformly or unevenly Enhance the diastolic function of the heart. For example, different gas chambers are fed into and out of gas through separate gas inlets at the bottom, and the gas inlets of each chamber are collected on a tube to connect with the bottom, and the specific needs are fed back to the set program to control the gas intake and gas outlet The timing and flow rate can be adjusted to achieve uneven and asynchronous assisted relaxation. During end-systole and early diastole, the ventricular assist device acts like a loaded spring, exerting negative pressure on the epicardial surface and helping the ventricle to fill.

In another embodiment of the present invention, as shown in Figures 4 and 5, the inner membrane of the flexible balloon further has folds, and when inflated, most of the gas chamber expands inwards to contact the epicardium of the heart.

In the ventricular assist device of the present invention, the gas chamber of the flexible balloon is longitudinally oriented when inflated, and the gas chamber is foldable when deflated, enabling rapid and minimally invasive implantation. The present invention is not sutured to the heart, and the damage to the heart is minimal, because the heart is naturally sucked into the flexible air bag. Specifically, when the heart exits the ventricular assist device (i.e., extrudes from the flexible balloon), the curvature of the flexible balloon needs to be reversed, but its stiffness (when pressurized) can resist the curvature reversal due to the placement of the elastic energy storage element.

As shown in Figures 6 and 7, the bottom of the ventricular assist device has a channel opening 7 for aspiration of fluid that may exist between the heart and the device. Biocompatible lubricants, anticoagulants, antifibrotic agents, drugs or antibiotics, etc. may be injected between the heart and the flexible balloon, and the channel opening at the bottom of the device is useful for sucking out the fluid that may accumulate between the heart and the device very helpful.

The flexible balloon of the ventricular assist device of the present invention has two layers of biocompatible membranes, and one or more gas-filled bladders separate the two layers of biocompatible membranes, which can prevent adhesion between the epicardial surface of the heart and the chest wall . In addition, in order to make the ventricular assist device easy to remove, a film can be covered on the outside of the device to slow down fibrous adhesions. As the thin film, a biomedical material is used. The ventricular assist device of the present invention is made of suitable, biocompatible, biostable, and implantable materials to minimize the incidence of infection associated with implantation of medical equipment.

When manufacturing the ventricular assist device of the present invention, it is preferable to use 3D printing technology to make the airbag, obtain the specific heart contour of the patient according to imaging technology or other techniques, and print out the airbag that best fits the patient, so that the distance between the airbag and the heart is very small. Fitted snugly and without free air, the top seals around the heart.

The ventricle assisting device of the present invention is connected with an external air circuit assembly during practical application. As shown in Figure 8, the air pump is used to inflate the flexible airbag of the ventricular assist device, and the pressure in the flexible airbag is monitored and fed back to the control device through the pressure sensor, and then the inflation and deflation operations are controlled by the control device, specifically by operating the control valve. accomplish.

Claims (6)

1. A ventricular assist device with diastolic function, the device comprises a flexible air bag that fits the heart, the top of the flexible air bag is open, and there is a pneumatic lock at the top position; The flexible airbag is formed by two layers of biocompatible film, and the biocompatible film extends upward for a section to form the pneumatic lock in contact with the heart, and a locking structure is formed between the pneumatic lock and the heart, so that the flexible airbag is in contact with the heart. There is no free air between the hearts; Below the pneumatic lock, one or more gas chambers are formed between the inner membrane and the outer membrane, and the gas inlet and outlet are respectively connected to each gas chamber; The ventricular assist device has an elastic energy storage element disposed on the adventitia of a flexible balloon, the elastic energy storage element being a frame made of a shape memory alloy or polymer; the elasticity is utilized when the heart pressure is below the end-diastolic pressure The energy storage element creates a negative pressure that promotes ventricular filling, and the elastic energy storage element acts to limit filling when the cardiac pressure exceeds the end-diastolic volume. 2 . The ventricular assist device with diastolic function according to claim 1 , wherein the intima of the flexible balloon has folds, and when inflated, most of the gas chamber expands inwards to contact the epicardium of the heart. 3. The ventricular assist device with diastolic function according to claim 1 or 2, characterized in that the gas chamber is longitudinally oriented when inflated, and the gas chamber is foldable when deflated. 4. The ventricular assist device with diastolic function according to claim 1 or 2, characterized in that the top opening of the flexible balloon is small, and the pneumatic lock forms a closed structure in a manner of clamping or wrapping the heart. 5. The ventricular assist device with diastolic function according to claim 1 or 2, characterized in that the bottom of the ventricular assist device has a channel opening for sucking out the fluid that may exist between the heart and the device. 6. The ventricular assist device with diastolic function according to claim 1 or 2, characterized in that, the outside of the ventricular assist device is covered with a film made of biomedical materials.

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