WO2017178904A1

WO2017178904A1 - Implantable cardiac assist device using twisting extra ventricular compression

Info

Publication number: WO2017178904A1
Application number: PCT/IB2017/051532
Authority: WO
Inventors: Mahdi DALIRIREZAGHOLI GHESHLAGHI
Original assignee: Dalirirezagholi Gheshlaghi Mahdi
Priority date: 2016-04-10
Filing date: 2017-03-16
Publication date: 2017-10-19

Abstract

The implantation of permanent or temporary mechanical assist devices has become a viable alternative therapy for heart failure by which ventricular function can be augmented in a diseased heart. These devices help to assist a damaged or weakened heart by sharing cardiac output with the heart via various mechanisms. Assist mechanical devices are divided into two categories in this work: 1. Ventricular assist devices (VADs) with the device directly contacting the blood; 2. Extra-cardiac compression devices (ECCDs) that indirectly assist blood pumping by compression of cardiac or arterial tissue. The majority of current and past devices those pumping blood is VADs, which employ a rotating impeller or positive-displacement and valve mechanism, exposing patients to risks of hemolysis and thrombosis. Furthermore, most of such devices require a surgical operation involving penetration of ventricular or arterial walls and increases risk of complications.

Description

IMPLANTABLE CARDIAC ASSIST DEVICE USING TWISTING EXTRA

VENTRICULAR COMPRESSION

Description

Background:

Patients with mild to moderate heart failure and recently those with more severe heart disease have been shown to benefit from drug therapy. Nevertheless, the survival and quality of life of patients with severe heart failure remain limited. Heart transplantation is the only therapy which improves functional capacity, quality of life and provides a better life expectancy with survival rates for one and five years of up to 94% and 78%, respectively.

In recent years, novel ECCDs which compress tissue and muscles to indirectly assist blood pumping have been developed to circumscribe problems associated with blood-contacting devices and the risks involved with piercing arterial and ventricular walls. Not only do ECCDs aim to reduce risks from the patient and surgeon perspective, the complexity of engineering an intra-corporeal extra-cardiac device is also reduced.

In contrast to VADs, biventricular and univentricular ECCDs assist the failing heart by compressing cardiac and aortic tissues, thereby avoiding direct contact of blood with artificial surface. ECCDs can be further divided into two groups depending on the way they are powered. Devices in the first group are powered by an extracorporeal source such as pneumatic or electrical drives. Devices in the second group are powered by energy sources within the patient's body like Badylak or Chiu Devise those described below.

Technical problems

A. VADs expose a patient to potentially serious complications. The main cause of complications is direct contact of the patient's circulation to artificial surfaces as well as the invasive surgical procedure. Hemorrhage is the most common complication associated with placement of LVAD. Excessive perioperative bleeding occurs between 20% and 50% of the time; however, this rate decreases as the experience with device implantation grows. About 50% of patients required reoperation for bleeding, while death due to bleeding was reported to be in the range of 0 to 15%. Infection is another serious complication and the primary cause of death in long-term LVAD patients. The mortality is up to 70% of LVAD recipients. Failure of the LVAD was the second most frequent cause of death in the device group, which can occur in multiple parts of a device or in the controller.

By improvement of technology, pumping mechanical failure was decreased (0.03% in lth generation to 0% in 2^nd and 3^rd generation of LVAD). Right heart failure (RHF) is also a common complication associated with VADs, occurring in nearly 40% of recipients. Right heart failure is also associated with high transfusion rate and increased rate of end-organ failure. The number of days in the intensive care unit and the mortality rate are also increased in RHF patients. Thromboembolism is an important complication that occurs in 20% of patients receiving a left or right VADs. The main cause of thromboembolism is contact of device surface to blood and this event depends on many factors like device profile, patient condition and anticoagulant regimen. It due to cerebrovascular and peripheral embolization. Other less common complications are ventricular arrhythmias, stroke, neurological and psychological dysfunction, hemolysis and other organs dysfunction.

B. Because of the configuration of current ECCDs, a major surgery, such as thoracotomy and sternotomy, is required for the implantation. Their use in earlier stage patients is thus restricted and it would be only beneficial to use the ECCDs for long-term application due to the invasiveness. Large device and complex mechanism will make the surgical procedure as well as the intracorporeal fixation challenging. Size and weight of the device is a critical issue in smaller patients. Other significant risks for the direct compression devices are the adhesion and tissue ingrowth. Cardiac recovery has been reported after mechanical assistance by VADs allowing the removal of the device. If this remodeling process would be expected, besides the invasive surgery required to withdrawal the ECCD, device removal could result in substantial damage to the cardiac or vessel muscles due to tissue adhesion or ingrowth. Another situation in which a device removal is necessary is body rejection. Despite elimination or minimization of the direct blood contact in the ECCDs, the adjacency between artificial surfaces and internal organs are not avoidable. Further investigation on potential immune system activation due to the ECCDs is necessary before they are proven beneficial or capable of being alternatives to current VADs.

An important question to ask in the cardiovascular disease arena is whether VAD can replace heart transplantation as a viable alternative and be even more beneficial to patients? It is necessary to find an alternative to heart transplantation quickly but current VADs cannot meet the equivalent reliability and longevity advantages of heart transplantation. Alternative solutions are ECCDs; those have the potential to replace heart transplantation and can revolutionize cardiovascular disease therapy.

Summary of the invention:

The implantation of permanent or temporary mechanical assist devices has become a viable alternative therapy for heart failure by which ventricular function can be augmented in a diseased heart. These devices help to assist a damaged or weakened heart by sharing cardiac output with the heart via various mechanisms. Assist mechanical devices are divided into two categories in this work: 1. Ventricular assist devices (VADs) with the device directly contacting the blood;

2. Extra-cardiac compression devices (ECCDs) that indirectly assist blood pumping by compression of cardiac or arterial tissue.

The majority of current and past devices those pumping blood is VADs, which employ a rotating impeller or positive-displacement and valve mechanism, exposing patients to risks of hemolysis and thrombosis. Furthermore, most of such devices require a surgical operation involving penetration of ventricular or arterial walls and increases risk of complications.

Description of the invention:

This invention includes a device which helps to the muscles of right and left Vernacular with the Spiral pressure from the outside and increases the heart output. The inherent nature of heart muscle which is not considered in the previous inventions is the spiral formation of it which causes blood pumping with the upward spiral motion. This device constitutes four blades which are connected to the device-motivating system box from the downside and to a ring inside the atrial groove from the upside. Since they ate fixed from the upper side and have a rotational motion from the lower side, the upward spiral pressure is exerted to the Vernaculars. There is the possibility to change the size in the arms and upper ring in order to be adjusted for different sizes of heart during the installation. The arms are made of Poly tetra fluoro ethylene or PTFE or light metal with soft pads in the inner part to avoid the damage to the heart.

In the lower part of the device, the parts of its engine is available which is designed very simply to be able to change the energy generated from the movement of gears and diaphragm and moves back and forth into the rotational form and transfer it to the blades as the energy increases.

The gears and diaphragm distend and contract the Thorax cavity at each breath due to the contraction of respiratory muscles and this motion can be used to create rotational motion and the electricity is not required.

There is a battery in the device-motivating system box which saves the motional energy to be used when needed.

In order to facilitate, the blades can be placed inside an outer cover (cup). The devices can be installed with the Thoracotomy incision to have a better access to the gears and diaphragm and not to do midline sternotomy for the critically ill patients. Brief description of drawings:

Figure 1 : General view of the invention

Figure 2: Upper view

Figure 3: lower view

Figure 4: Blade's

Figure 5: Blade's lower and upper part

Detailed description of drawings:

The failure heart 1 is placed inside the device in such a way that the rotational force is given only to the ventriculars and the atrials is placed outside. The blades 2 of the device are formed of four to six, according to the heart size. These blades have a low width at the downside and they become wider as they go up. There is a curve on both sides of the blade in the same direction in order not to be entangled during the rotational motion of the blades. It is connected to a round and motion generative plate 4 from lower side and it is fixed on the upper side beside the blades and between the distance of ventricular and atrial. The high width of blades causes the pressure to be transferred at a wider scope to the ventricular wall and reduce the damage.

The whole blades and the motion generative plate 4 are placed inside a two-layered cover 3 in order to avoid the direct contact between the mechanical and rotational parts and the heart and surrounding parts. This cover is made of silicon and non-sticky material to body tissues and it is covered with a coating of Hydrogel from the inside. The cover 3 is in the shape of a cup in which the heart is placed.

The motion generative plate 4 is the connecting place of the lower section of the blades. This plate causes the twist motion by creating a rotational motion with an angle of 15 to 20 and transferring it to the blades. The momentum which makes the round plate to rotate can be hydraulic, pneumatic, or electrical.

The motion generative connection canulla 5 is connected to the lower parts of the plate through which it is connected to the energy source outside the body which can be an electric battery or a pneumatic motor. This canulla is made of PTEF to minimize the infection. Figure 2 is the upper view of the device at the resting manner 6 and open blades where the diastolic phase of the heart is seen. Moreover, the upper view of the device in the form of blade rotation 7 at around fifteen degrees which causes twist motion since it is fixed from the upper side and the inner side of the device is not seen well.

In Figure 3, the cross section of the device with the lower view of the blades after the deletion of round plate in the resting manner 8 is seen. In this situation, the blades are at the open manner without rotation. Moreover, the cross section of the device with the lower view of the blades after the rotation at around fifteen degrees can be seen in this figure. In this situation 9, the blades get closer to each other and to the center of round plate.

In Figure 4, the following parts are showed:

No. 10: Blade's midline: the midline and axis of the blade which moves on the round plate

No. 11: Blades' place A: the axis and location of the legs of the blades in diastolic phase and open-blade manner

No. 12: motion path: the motion path of the blades which is anti-clockwise and toward the center with the rotation of 15 degrees.

No. 13: blades' place B: the axis and place of legs of the blades in diastolic phase after the rotation

No. 14: Spiral motion direction: Spiral motion direction which is anti-clockwise

The lower part of the blades 15 is placed on the Ventricle curvature and the rotational force is applied to the heart to cause twisting motion. This part of the blade is firm and is made of compressed carbon or metal. The upper side of the blade 16 is flexible and after it is bended on the atrial, it will be fitted and fixed up on the heart Ventricular to avoid the motion of the upper side of the blade while the lower side of the blade moves. Its material is flexible and formable. The flexible part is installed on the upper 17 firm side of the blade. The connection place is actually where the atrials are connected to the ventriculars 19.

The moving part of the blade is bended on the heart 18 after the heart is placed inside the device in order to fix the blade on the heart. Before the device is placed, this part of the device is open and after the placement, it is bent.

If we accept the cardiac assist device as an appropriate alternative to transplantation, the problem of moving in the optimal direction as a technology and cost-effectively meeting the demand needs to be addressed. The following four guidelines are proposed to help in choosing the best design:

1. The less blood contacting foreign surfaces due to less complications and the longer the device will survive.

2. The second guideline is related to device energy. Advancements in LVADs and batteries have allowed small batteries to supply devices with much lower energy requirements. However, the need for extracorporeal source of energy persists, leading to further burden and higher risks for the patient. An intracorporeal energy system would be ideal for cardiac assist devices.

3. The third guideline is to reduce percutaneous requirements of devices those including catheter for fluid, blood or gas, controller signal wire and power cable. Infection is prevalent among LVAD patients and is mainly attributed percutaneous wiring and other parts to extracorporeal devices. Technology advancements should focus on reducing percutaneous leads towards fully wireless systems similar to today's pacemakers.

4. The fourth guideline is to aim for smaller devices with simple and replaceable parts because more mechanical parts means higher breakdown risks and results in shortened device lifespans.

With consideration to the above guidelines, the ideal device will have no contact to blood and extracorporeal surfaces, lesser dependency on extracorporeal sources of energy and is as simple as possible. While seemingly simple goals still require a large amount of research and development to achieve such a device.

Some ECCDs, despite being at a concept stage, match the guidelines for an ideal device better than current VAD technologies. Because of more research and advances in fields such as LVADs, and because of small size and only one moving part, impeller-based pumps have become the more popular therapy. Nevertheless, the inherent benefit of ECCDs not requiring contact to the blood to avoid complication has a promising future as an alternative.

Advantageous Effects of Invention

With inspiration from the physiologic movement of the heart and the type of cardiac muscles' arrangement, a ventricular assist device (VAD) was designed which can be a favorable solution to the problems facing VADs.

Claims

IMPLANTABLE CARDIAC ASSIST DEVICE USING TWISTING EXTRA VENTRICULAR COMPRESSION Claims

1. An implantable cardiac assist device using twisting extra ventricular compression comprising:

a. blades 2;

b. two-layered cover 3;

c. motion generative plate 4;

d. motion generative connection canulla 5.

2. The blades of Implantable cardiac assist device are formed of four to six.

3. The device of claim 2: The whole blades and the motion generative plate 4 are placed inside a two-layered cover.

4. The device of claim 2: blades have a low width at the downside and they become wider as they go up. There is a curve on both sides of the blade in the same direction.

5. The device of claim 1: the whole blades and the motion generative plate 4 are placed inside a two-layered cover in order to avoid the direct contact between the mechanical and rotational parts and the heart and surrounding parts.

6. The device of claim 5: cover is made of silicon and non- sticky material to body

tissues and it is covered with a coating of Hydrogel from the inside.

7. The device of claim 5: the cover is in the shape of a cup in which the heart is placed.

8. The motion generative connection canulla of Implantable cardiac assist device is

connected to the lower parts of the plate through which it is connected to the energy source outside the body.

9. The device of claim 3: the device in such a way that the rotational force is given only to the ventriculars and the atrials is placed outside.

10. The motion generative plate of Implantable cardiac assist device is the connecting place of the lower section of the blades.

11. The device of claim 10: this plate causes the twist motion by creating a rotational motion with an angle of 15 to 20 and transferring it to the blades.

12. The device of claim 10: the momentum which makes the round plate to rotate can be hydraulic, pneumatic, or electrical.

13. The device of claim 8: canulla is connected to the energy source outside the body

14. The device of claim 8: canulla energy source can be an electric battery or a pneumatic motor.

15. The device of claim 8: canulla is made of PTEF to minimize the infection.