Self-sealing cannula

Abstract

To disclose a self-sealing cannula that prevents the need for multiple cannula insertion sites, can significantly reduce blood recirculation, allows easy removal of the cannula, and eliminates the need to suture or insert an occluding member and a method of using the same.SOLUTION: A cannula can be implemented as a single lumen cannula or as a double lumen cannula 1, and can be used together with a VAD for heart support, or an ECMO and a pump-oxygenator for respiratory assistance. A cannula body is attached to a self-sealing instrument through a self-sealing mechanism mounted on a ventricular wall or an atrial wall, such that blood is drawn into a lumen using an external pump and is returned to a circulatory system through another cannula. In a case of an embodiment of the double lumen cannula 1, blood is drawn into a drainage lumen of the double lumen cannula and is returned through an infusion lumen at a desired position.SELECTED DRAWING: Figure 2A

Description

REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on co-pending and commonly owned U.S. Provisional Patent Application No. 62 / 079,876, filed November 14, 2014, with the U.S. Patent and Trademark Office, entitled "Self-Sealing Cannula," the specification of which is incorporated herein by reference.

[0002] [Government Licensing Rights] This invention was made with government support under Grant No. HL082631 awarded by the National Institutes of Health. The government has certain rights in this invention. [Technical Field]

[0003] The present invention relates generally to cannula systems, and more particularly to self-sealing cannula systems for draining blood from and / or infusing blood into the circulatory system, and methods for using such systems. [Background technology]

[0004] The human cardiovascular system functions as the body's material transport network. It interacts with the interstitial space through diffusion sites throughout the body, exchanging fluids, hormones, electrolytes, nutrients, and other substances. This is accomplished by the pumping function of the human heart and the circulation of blood through the blood vessels. The heart, under appropriate pressure, pumps blood from the low-pressure venous system and pumps it into the arterial side of the circulation to maintain the body's circulatory needs. The heart basically consists of four chambers. These include two thin-walled atria separated from each other by the interatrial septum and two thick-walled ventricles separated by the interventricular septum. The heart consists of two separate pumping systems in series. The right atrium and right ventricle function as a single unit to move venous blood from the large veins (superior vena cava (SVC) and inferior vena cava (IVC)) to the pulmonary circulation. In the pulmonary circulation, venous blood passes through the human lungs and is oxygenated. The left atrium and left ventricle work together to pump blood from the pulmonary veins into the high-pressure systemic circulation, where it circulates through the body and returns to the right atrium via the SVC and IVC.

[0005] Heart failure occurs when the heart is unable to pump enough blood to meet the body's needs. Heart failure (HF) affects 5.7 million patients in the United States and contributed to approximately 280,000 deaths in 2008 (Roger et al. Circulation. 2012;125(1):e2-220). HF places a significant burden on healthcare providers and is expensive to treat. The estimated direct and indirect costs of HF in the United States in 2010 were $39.2 billion (Centers for Disease Control and Prevention, 2010 Heart Failure Fact Sheet). Despite medical advances, the prognosis for HF, especially in advanced stages, remains poor. Patients with advanced HF require mechanical circulatory support or heart transplantation to survive. Heart transplants are limited by the supply of donor organs. Mechanical circulatory support is often achieved using a ventricular assist device (VAD), a mechanical pump designed to augment or replace the function of one or more chambers of a failing heart. Although increasing, the use of VADs has been limited by the need for major surgical intervention.

[0006] Furthermore, lung disease is the third most deadly disease in the United States, accounting for one in six deaths (American Lung Association). Despite spending of $154 billion, 400,000 deaths are due to pulmonary causes each year (Sanovas, "Lung Disease"). Lung failure can occur acutely or chronically. Chronic obstructive pulmonary disease (COPD) is one of the most common lung diseases and the fourth leading cause of death in the United States. Acute respiratory distress syndrome (ARDS) typically afflicts 190,000 patients annually, with an average survival rate of 30-50% (Rubenfeld et al. N Engl J Med 2005;353:1685-93). When pulmonary failure occurs, either mechanical ventilation or extracorporeal membrane oxygenation (ECMO) must be implemented to oxygenate the blood and maintain the body's oxygen needs. Although mechanical ventilation is effective for short-term support, the sustained tidal volume and commonly used airway pressures can damage the lungs. ECMO closely simulates physiological gas exchange but requires cannulation to access blood. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent No. 7,473,239 Summary of the Invention [Problem to be solved by the invention]

[0008] In current clinical practice, both VAD and ECMO require extensive invasive surgical procedures to implant these devices using a cannula set. Therefore, only a limited patient population can receive treatment based on these devices. A cannula is a medical tube inserted into the body to drain and infuse blood. The main problems with commercially available cannulae for ECMO (U.S. Pat. No. 7,473,239, inventors Wang et al.) are: (1) the need for multiple cannula insertions and the insertion of large-diameter cannulae cause excessive trauma to the patient; (2) when blood is withdrawn from the right atrium or central veins and reinfused, blood recirculation results in insufficient extracorporeal oxygen supply; (3) the placement of the drain lumen relative to the veins results in insufficient venous blood drainage; and (4) the direct insertion of the cannula into the heart causes bleeding due to the securing of surgical sutures. Similarly, currently commercially available cannulae for VADs also suffer from the same problem of causing undue trauma. Therefore, a minimally invasive, efficient and simple percutaneous cannula system is needed for ECMO and VAD. [Means for solving the problem]

[0009] The present invention discloses a self-sealing cannula. The self-sealing cannula can be configured as a double-lumen cannula or a single-lumen cannula. Figure 1 shows a self-sealing cannula, a double-lumen cannula (DLC). The self-sealing DLC ​​includes a drain cannula, an infusion cannula, a self-sealing double umbrella made of wire mesh, and a self-closing iris made of wire mesh. The self-sealing DLC ​​can be used to directly remove blood from the right ventricle through the drain lumen and infuse blood into the pulmonary artery via the infusion lumen via a minimally invasive transpericardial procedure. This configuration can be used for ECMO respiratory support or mechanical circulatory support of the right heart. The infusion lumen has a smaller diameter than the drain lumen and is partially located inside the drain lumen. A competent (non-regurgitant) native semilunar valve between the ventricle and the artery serves to minimize "recirculation" flow, i.e., the backflow of arterial drainage countercurrent to the ventricular inflow. The cannula may also be used to remove blood from the left ventricle and return it to the aorta for mechanical circulatory support of the left heart.Hemostatic felt is incorporated inside the closure formed by the double umbrella and iris wire mesh for hemostasis.

[0010] A double-umbrella (disk) structure is provided around the tip of the drainage cannula to provide hemostasis after the DLC is inserted into the right heart (Figure 1). The double-disk structure is made of wire mesh and can be pushed into the sheath introducer along with the dual-lumen cannula. Instead of traditional surgical sutures, which require a larger insertion site and open chest surgery, the wire mesh expands slightly radially and contracts axially upon release from the sheath introducer to seal the insertion site on the ventricular wall and conform to the epicardial and endocardial walls. Therefore, the cannula can be easily placed into the heart through a small hole in the pericardium, reducing surgical and traumatic complications for the patient. The infusion and drainage lumens of the DLC can be placed using a conventional needle puncture and a Swan-Ganz-type guide catheter. After needle puncture, the guide catheter is advanced into the pulmonary artery. Using a dilator, the tip of the infusion lumen is advanced into the pulmonary artery through the guide catheter. As the tip of the infusion lumen advances, the sheath with the DLC acts as an introducer / dilator, further enlarging the insertion site. Once the drain tip is properly positioned, the sheath is removed. The double umbrella springs back into its predefined shape, sealing the insertion site and anchoring the DLC onto the ventricular wall.

[0011] The dual-lumen cannula is placed into the heart, secured to the septum or muscle layer at the incision site, and emerges through the skin so that a VAD can be connected to provide cardiac support or an ECMO system can be attached to provide respiratory support. The same procedure can be performed on the left heart to assist the left heart. The self-sealing cannula may also be configured as a single-lumen cannula for draining or infusing blood.

[0012] Cannula placement can be performed using minimally invasive, surgical, and endovascular techniques. (a) Small incision ventricular access: A subxiphoid approach is used to access the diaphragmatic aspect of the right ventricle, while a small left thoracotomy or subcostal incision is used to access the left ventricular apex. The cannula is designed to be placed without temporary cardiopulmonary bypass. This is particularly advantageous for left-sided support, since current extracorporeal ventricular assist devices that involve left ventricular cannulation generally require cardiopulmonary bypass for placement. (b) Seldinger-based ventricular and arterial access: The ventricle is accessed using a hollow needle. With fluoroscopic and / or transesophageal echocardiographic guidance, a guidewire / guide catheter is passed through the hollow needle, into the ventricular cavity, and then into the distal outflow artery. A self-sealing double umbrella, mounted externally to the guidewire / guide catheter within the sheath, is deployed and gradually expanded until it locks in place and is released to seal the access site. The sealing is similar to how a ventricular septal occluder circumferentially seals a wound wider than a ventriculotomy wound, both inside and outside the ventricular cavity. (c) Loading and Positioning of the Cannula: The cannula is preloaded and packaged with the sheath, dilator, and guidewire / catheter. Using fluoroscopic / echocardiographic guidance based on markers on the cannula, the cannula is positioned so that the distal portion of the infusion cannula is within the proximal portion of the artery and the distal portion of the drainage cannula is within the ventricular lumen. A locking mechanism secures the cannula to the double umbrella discs in the desired position. In the case of a single-lumen cannula, the distal tip of the cannula is located within the ventricular lumen. (d) Cannula Removal: The cannula can be removed by a screw locking mechanism between the outer surface of the cannula body and the central hole of the double umbrella. When the cannula body is removed, the hidden iris springs back and acts as a valve, closing the hollow hole.

[0013] Many of the advantages of the present invention may be better understood by those skilled in the art by reference to the following drawings. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic illustration of a double lumen cannula (DLC) assembly including a self-sealing cannula positioned within the right heart and pulmonary artery in accordance with an aspect of an embodiment of the present invention. [Figure 2A] FIG. 2 is an enlarged cross-sectional view of the self-sealing DLC ​​of FIG. 1 and its components. [Figure 2B] 2 is an enlarged cross-sectional view of the self-sealing DLC ​​of FIG. 1 in a sheath with two dilators and a guide catheter. [Figure 3] 3A and 3B are enlarged cross-sectional views of a self-sealing single lumen cannula according to a further aspect of an embodiment of the present invention, respectively. [Figure 4A] FIG. 2 is a schematic diagram of the self-sealing DLC ​​of FIG. 1 placed in the right ventricle and pulmonary artery. [Figure 4B] FIG. 2 is a schematic diagram of the self-sealing DLC ​​of FIG. 1 placed in the left ventricle and aorta. [Figure 4C] FIG. 3B is a schematic diagram of the self-sealing single-lumen cannula of FIG. 3A positioned in the right ventricle as a drainage cannula. [Figure 5A] 2 is a schematic diagram of the DLC of FIG. 1 when the insertion site is being enlarged with a first dilator to place the injection cannula of the self-sealing DLC ​​into the right ventricle. [Figure 5B] 2 is a schematic diagram of the DLC of FIG. 1 during the enlargement of the insertion site with a second dilator for placement of the evacuation cannula of the self-sealing DLC ​​within the right ventricle. [Figure 5C] 2 is a schematic diagram of the DLC of FIG. 1 when positioned within the right ventricle and pulmonary artery. [Figure 5D]Schematic diagram of the DLC of Figure 1 after placement within the right ventricle and pulmonary artery. [Figure 5E] FIG. 2 is a schematic diagram of the self-sealing mechanism of FIG. 1 using a double umbrella after the DLC has been removed from the right ventricle. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention, summarized above, will be better understood by reference to the following description, claims, and accompanying drawings. The following description of embodiments, while enabling, is not intended to limit the preferred invention, but is intended to serve as a specific example. Those skilled in the art will readily appreciate that they can use the disclosed concepts and specific embodiments as a basis to modify or design other methods and systems for achieving the same purposes of the present invention. Those skilled in the art will also realize that such equivalent assemblies do not depart from the spirit and scope of the present invention in its broadest form.

[0016] 1 is a schematic diagram of a self-sealing cannula in accordance with an embodiment of the present invention, more particularly a self-sealing double lumen cannula (DLC) configured to remove blood from the right ventricle through the outer lumen of the DLC and return the blood to the pulmonary artery. A double umbrella device serves as a sutureless self-sealing mechanism and a holder for the DLC in the appropriate position on the right ventricle.

[0017] A DLC assembly according to one embodiment of the present invention is shown in FIG. 2. The DLC assembly 1 includes a circular drain cannula, the interior of which forms the drain lumen 2, a side-fused tubular cannula 3, the interior of which forms the infusion lumen 4, and a compressible double umbrella 6. The infusion cannula has a thick-walled infusion port 7, a thin-walled circular tube 4 fitted into the side wall of the drain lumen, and a circular extension 5. A portion of the infusion cannula extends through the drain cannula lumen. Although the extension 5 is a thin-walled circular tube, it is reinforced with a wire frame. Thus, the extension 5 is radially rigid yet axially flexible and compliant. Additionally, the extension 5 of the infusion cannula portion has an exposed zigzag wire frame (as shown). This allows blood returning from the infusion lumen to be distributed axially and radially into the target vessel and prevents the return blood flow from being blocked when the distal tip is positioned against the vessel wall. The double umbrella 6 is attached to the drainage cannula body. The disk-like double umbrella 6 has a pair of outward-opening wire mesh umbrellas 10, a metal ring 9, and an inward-opening wire mesh iris 11 (the configuration of the iris 11 is similar to the iris or shutter of a camera). The wire mesh is preferably formed from a shape memory alloy. The shape memory alloy is radially compressed to a diameter smaller than its intended diameter during deployment and returns to its intended functional shape when warmed by the patient's own body temperature to the transformation temperature of the shape memory alloy. In particular, in this embodiment of the present invention, the wire mesh of the double umbrella 6 is formed from nitinol (an alloy typically made of approximately 55%-56% nickel and 44%-45% titanium by weight). The outer configuration of the double umbrella 6 is somewhat similar to atrial and ventricular septal defect occluder devices (such as the Amplatzer occluder device, available from AGA Medical Corp., Golden Valley, Minnesota).However, as described in more detail herein, the outer configuration of the double umbrella 6 has been significantly improved for use with a cannula assembly, allowing for self-sealing after removal of the cannula extending through the double umbrella 6.

[0018] Nitinol is an alloy of nickel and titanium. It has superelastic properties, which refer to its ability to deform at low temperatures and then return to its original shape above a certain temperature (transformation temperature). A process called shape setting is used to force Nitinol into a desired shape. Typically, this process involves forcing the material into the desired shape on a mandrel at 450-550°C for 10-80 minutes, depending on the type of Nitinol material. This process is known to those skilled in the art. In at least one embodiment, the optimal heat treatment conditions for a 0.01-inch cross-sectional diameter Nitinol wire (Johnson Matthey Inc., West Chester, Pennsylvania) are 500°C for 70 minutes, which results in a transformation temperature of 27°C. In another embodiment, the transformation temperature may be between 30°C and 37°C. Below the transformation temperature, the material is not stable and its shape is easily changed. Cannula assemblies incorporating nitinol wire mesh constructions and methods of use and manufacture thereof are described in PCT International Application No. PCT / US14 / 46978 entitled "Self-Expanding Cannula," the specification of which is incorporated herein by reference in its entirety.

[0019] Alternatively, the wire mesh may be highly flexible, allowing it to be radially compressed (e.g., by inserting the wire mesh and cannula into a frangible sheath for initial insertion of the cannula into a patient's ventricle, as described further below), and then return to its normal, expanded shape after the radial compression is removed. Upon release from the introducer sheath, the wire mesh is radially expandable, sealing the insertion site on the ventricular wall and conforming to the epicardial and endocardial walls. Similarly, the iris 11 is preferably formed of the same shape-memory alloy wire mesh as the double umbrella. A circular metal ring 9 may be attached to the wire mesh to provide a locking mechanism for a drainage cannula body affixed to the double umbrella 6. Preferably, external threads are formed on the circular outer surface of the drainage cannula. Preferably, corresponding internal threads are formed on the inner surface of the double umbrella ring. The DLC can then be secured in place or removed from the double umbrella 6 by turning the screw in or out. The iris 11 of the double umbrella 6 functions as a self-sealing shutter, similar to the circular shutter of a camera. When the DLC is in use, the iris is forced open by the drainage cannula body. When the drainage cannula is removed, the iris recoils, sealing the central hole of the double umbrella 6. The tip of the drainage cannula is preferably made of a biocompatible metal, such as titanium, and is embedded in the double umbrella 6. Therefore, the tip of the drainage cannula protrudes slightly from the ventricular wall, providing excellent blood drainage and preventing tissue overgrowth into the cannula lumen. The remainder of the cannula is made of a biocompatible polymer, such as polyurethane or PVC. The circular body of the drainage cannula is a reinforced wire. The metal tip and cannula body are molded and fused together. Figure 2B shows the self-sealing DLC ​​1 mounted within the sheath 12 along with two dilators 13, 14, and a guide catheter 15. The double umbrella 6 and its iris 11 are compressed within a sheath 12 .

[0020] Alternatively, a portion of the graft containing a predetermined purse string suture may be sewn onto the double umbrella to perform the function of the iris described above and seal the central hole of the double umbrella after the cannula body is removed. When the evacuation cannula body is withdrawn from the double umbrella by unscrewing it, the double purse string suture is pulled and knotted in the lumen of the graft to seal the hole.

[0021] In one aspect of an embodiment of the present invention, a single-lumen cannula assembly is shown in FIG. 3A. The self-sealing single-lumen cannula includes a circular tube 16 having an inner surface 17 forming a drainage or infusion lumen, and a double umbrella 19 with an iris 24. The proximal end is a connector port 18. FIG. 3B shows the self-sealing single-lumen cannula 16 assembled within a sheath 20 along with a dilator 21. The dilator 21 has a central bore 22 for passage of a guide catheter or guidewire 23. The double umbrella 19 is compressed by the sheath 20, and the iris 24 is opened by the cannula body within the sheath 20. In this configuration, the single-lumen cannula preferably includes a threaded connection to the interior of the double umbrella 19, having a configuration similar to that described above with respect to the DLC.

[0022] Figure 4A is a schematic cross-sectional view of a DLC placed in the right ventricle wall. Blood is removed from the right ventricle through the drainage lumen of the DLC and returned to the pulmonary artery through the infusion lumen of the DLC. The double umbrella device seals the insertion site on both the endocardial and epicardial sides with a preformed, flexible, and conformable double umbrella wire mesh. The serif sealing iris is open.

[0023] Figure 4B is a schematic cross-sectional view of a DLC placed in the left ventricle apex. Blood is removed from the left ventricle through the drainage lumen of the DLC and returned to the aorta through the infusion lumen of the DLC. Again, a flexible and conformable double umbrella is placed at the apex to seal the insertion site. The DLC is placed in the same manner as described above for placement in the right ventricle.

[0024] Figure 4C is a schematic cross-sectional view of a self-sealing cannula configured as a single-lumen cannula. The self-sealing cannula is positioned in the right ventricle wall to withdraw blood from the right ventricle. An identical self-sealing compatible double umbrella seals the insertion site.

[0025] 5A-5E illustrate the deployment and removal of a self-sealing DLC ​​in the right ventricle and pulmonary artery according to an embodiment of the present invention. A needle is used to drill a hole in the right ventricle for passage of a guidewire. A Swan-Ganz balloon catheter can be used, which passes through the central lumen of the dilator inside the infusion lumen. A balloon guide catheter with an inflatable balloon is then inserted into the right ventricle with the inflated balloon and guidewire and advanced into the pulmonary artery. Once the guide catheter is positioned (which can be confirmed by fluoroscopy or echocardiography), the infusion lumen cannula with the dilator is advanced along with the guide catheter (FIG. 5A) until it contacts the epicardium of the right ventricle. The advancing conical tip of the dilator gradually enlarges the needle puncture site, pressing the infusion cannula against the right ventricle and into the pulmonary artery. At this time, a second dilator for the drainage lumen approaches the insertion site (FIG. 5B). The insertion site is further enlarged by the semi-conical dilator, allowing the tip of the DLC sheath to advance into the right ventricle (Figure 5C). Once the first half of the compressed double umbrella is positioned in the right ventricle, the DLC sheath can be withdrawn. A frangible sheath may be used here. After the sheath is removed, the first umbrella opens on the inside of the right ventricle and fits against the endocardium. Similarly, after the sheath is completely removed, the second umbrella opens on the outside of the right ventricle and fits against the epicardium (Figure 5D). The DLC is then in a suitable position for connection to a VAD for mechanical circulatory support or an ECMO system for respiratory support. When support is no longer needed, the DLC can be removed by unscrewing the cannula body and withdrawing it. As the cannula body exits the right ventricle, the outer iris of the double umbrella (which had been opened by the cannula body) rebounds to its preformed shape and seals the central opening of the double umbrella (Figure 5E).

[0026] Similarly, a DLC with the above characteristics can be placed in the left ventricle using the same approach (Figure 4B). In the case of a single-lumen cannula, only one dilator is required. The above-described approach can be easily adapted to place a single-lumen cannula (Figure 4C). Once the DLC or single-lumen cannula is placed in the circulatory system, its respective ports (exhaust port and infusion port) are connected to a VAD for cardiac assistance or an ECMO system for respiratory assistance.

[0027] Advantages of the present invention include any of the following: 1. Minimally invasive insertion and sutureless self-sealing of the cannula directly into the heart 2. Avoidance of multiple cannulation sites in the heart 3. Evacuation unimpeded by venous and wall obstructions 4. Low thrombosis potential and implantable drainage tip 5.Minimal blood recirculation

[0028] While preferred embodiments and specific variations of the basic concepts of the present invention have been fully described, various alternative embodiments, as well as specific variations and modifications of the embodiments shown and described herein, will be apparent to those skilled in the art upon understanding the basic concepts. It should therefore be understood that the present invention may be practiced otherwise than as specifically described herein.

Claims

1. a first cannula having a distal end and a proximal end; and a flexible, self-sealing closure attached to the first cannula approximately at the distal end of the first cannula; Equipped with the closure has a hollow elongated structure defining an interior opening; the first cannula is removably attached to the interior of the closure; the closure is configured to self-seal when the first cannula is removed from the closure. Self-sealing cannula system.

2. the self-sealing closure is deployable from a compressed state to an uncompressed state; In the compressed state, the outer wall of the closure defines an elongated hollow cylinder; In the uncompressed state, the outer wall of the closure defines an upper disc, a lower disc, and a generally cylindrical wall extending between the upper disc and the lower disc. The self-sealing cannula system of claim 1 .

3. further comprising a removable sheath enclosing the obturator and at least a portion of the first cannula; the removable sheath compresses the closure to the compressed state; The closure is further configured to automatically deploy from the compressed state to the uncompressed state when the sheath is removed within the patient's body.

3. The self-sealing cannula system of claim 2.

4. the closure is temperature responsive and further configured to expand from the compressed state to the uncompressed state in response to a temperature of the patient's body.

4. The self-sealing cannula system of claim 3.

5. the hollow cylinder further includes a first connecting member inside the hollow cylinder; The first cannula further includes a second connecting member on the exterior of the first cannula, the second connecting member being configured to be removably attached to the first connecting member.

3. The self-sealing cannula system of claim 2.

6. the first connecting member and the second connecting member have a threaded mating connection; 6. The self-sealing cannula system of claim 5.

7. The self-sealing cannula system of claim 1 , wherein the obturator further comprises a distal end and a proximal end, and a self-closing iris at the proximal end of the obturator.

8. The self-sealing cannula system of claim 7 , wherein the iris is configured to automatically close the proximal end of the obturator when the first cannula is removed from the obturator.

9. further comprising a second cannula positioned within the first cannula and extendable from a distal end of the first cannula. The self-sealing cannula system of claim 1 .

10. The self-sealing cannula system of claim 9 , wherein the second cannula has a distal end formed of an expandable wire frame.

11. 11. The self-sealing cannula system of claim 10, wherein the deployable wire frame of the second cannula is temperature responsive and configured to deploy in response to a temperature of the patient's body.

12. moreover, a blood pump attached to the first cannula; and a blood oxygenator attached to the second cannula 10. The self-sealing cannula system of claim 9, comprising:

13. The self-sealing cannula system of claim 1 , wherein the closure is formed of a temperature-responsive wire mesh.

14. The self-sealing cannula system of claim 13 , wherein the wire mesh further comprises a superelastic nitinol alloy.

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