Patent Application
20150290370
The present invention relates to an apparatus and method for forming a hole in a hollow organ and connecting a conduit to the hollow organ, and more particularly, to a surgical device and method for forming a hole in a heart, connecting a conduit to the heart and connecting a left ventricular assist device (LVAD) to the heart.
As the average age of the United States population increases, so do the instances of aortic stenosis. An alternative approach to the conventional surgical replacement of the stenotic aortic valve involves the use of an apicoaortic conduit. In this approach, the native aortic valve is not removed, and a prosthetic valve is implanted in a parallel flow arrangement. A connection conduit (or tube) connects the apex of the heart to the descending aorta. Somewhere along this conduit, the prosthetic valve is interposed. Thus, blood leaves the heart through the apex and travels through the conduit (with valve) to the descending aorta.
Until recently, surgical procedures to implant an apicoaortic conduit have included a single, long incision, such as in the 6.sup.th intercostal space, to expose the heart and allow retraction of the lungs to expose the descending aorta. Recognizing the potential for broader scale use of the apicoaortic conduit for aortic valve replacement, some surgeons are now attempting to use smaller incisions and are requesting development of surgical tools for a minimally invasive procedure. As an initial attempt to make the procedure less invasive, some surgeons have recently performed the following procedure.
The patient is placed on the table in the supine position. Anesthesia is induced, and the patient is intubated with a double-lumen endotracheal tube, which facilitates one-lung ventilation and allows the surgeon to work within the left chest. The patient is positioned with the left side up (90 degrees). The pelvis is rotated about 45 degrees, such that the femoral vessels are accessible. An incision is made over the femoral vessels, and the common femoral artery and vein are dissected out. Heparin is administered. Pursestring sutures are placed in the femoral artery and vein. The artery is cannulated first, needle is inserted into the artery, and a guidewire is then inserted. Transesophageal echo is used to ascertain that the wire is in the descending aorta. Once this is confirmed, a Biomedicus arterial cannula is inserted over the wire, into the artery (Seldinger technique). The arterial cannula is typically 19 or 21 French. Once inserted, the pursestring sutures are snugged down over tourniquets. A similar procedure is followed for the femoral vein. The venous cannula is usually a few French larger than the arterial cannula. Once both vein and artery are cannulated, the cannulae are connected to the cardiopulmonary bypass, and the capability to initiate cardiopulmonary bypass at any time is present.
A 1 cm incision is made in approximately the 7.sup.th interspace in the posterior axillary line; the videoscope (10 mm diameter) is inserted, and the left chest contents viewed. The location of the apex of the heart is determined, and the light from the scope used to transilluminate the chest wall; this allows precise localization of the incision. The incision is then performed; it is essentially an anterior thoracotomy, typically in the 6.sup.th interspace. Recent incisions have been about 10 cm long, but are expected to become smaller and smaller with time. A retractor is inserted and the wound opened gently. A lung retractor is used to move the (deflated) left lung cephalad. The descending aorta is dissected free from surrounding soft tissue to prepare for the distal anastomosis. This dissection includes division of the inferior pulmonary ligament. A pledgeted suture is placed on the dome of the diaphragm and positioned to pull the diaphragm toward the feet (out of the way). The pericardium is incised about the apex of the heart, and the apex is freed up and clearly identified.
On the back table, the apicoaortic conduit is prepared: a 21 Freestyle® valve is sutured to an 18 mm Medtronic apical connector. The valve is also sutured to a 20 mm Hemashield graft. The Dacron associated with the apical connector is pre-clotted with thrombin and cryoprecipitate. The assembly is brought to the field, and a measurement made from the apex of the heart to the descending aorta. The assembly is trimmed appropriately. A partial-occluding clamp is then placed on the descending aorta, and the aorta opened with a knife and scissors. The conduit (the end with the 20 mm Hemashield graft) is then sutured to the descending aorta using 4-0 prolene suture, in a running fashion. Once this is complete, the clamp is removed and the anastomosis checked for hemostasis. Blood is contained by the presence of the Freestyle® aortic valve. The apical connector is placed on the apex, and a marker is used to trace the circular outline of the connector on the apex, in the planned location of insertion. Four large pledgeted sutures (mattress sutures) of 2-0 prolene are placed; one in each quadrant surrounding the marked circle. The sutures are then brought through the sewing ring of the apical connector. A stab wound is made in the apex in the center of the circle, and a tonsil clamp is used to poke a hole into the ventricle. To date, bypass has been initiated at this point, but doing so may not be necessary. A Foley catheter is inserted into the ventricle, and the balloon expanded. A cork borer is then used to cut out a plug from the apex. The connector is then parachuted down into position. A rotary motion is necessary to get the connector to seat in the hole. The four quadrant sutures are tied, and hemostasis is checked. If there is a concern regarding hemostasis, additional sutures are placed. The retractor is removed, chest tubes are placed, and the wound is closed.
Surgical tools developed specifically to implant the apicoaortic conduit are expected to provide the means for a much less invasive procedure. The procedure is expected to be performed with a series of smaller thoracotomy incisions between the ribs, such as immediately over the apex of the heart. In addition to avoiding the median sternotomy, development of appropriate surgical tools is expected to avoid the need for cardiopulmonary bypass, so that the procedure can be performed on a beating heart. The diseased aortic valve does not need to be exposed or excised. The stenotic aortic valve is left in place and continues to function at whatever level it remains capable of, and the apicoaortic conduit accommodates the balance of aortic output.
The major obstacle to widespread adoption of this superior technique is the nearly complete lack of efficient devices to perform the procedure. Surgeons wishing to adopt the procedure must gather a collection of instruments from a variety of manufacturers. Often these instruments were created for quite different purposes, and the surgeon is forced to adopt them as required and manually manipulate them during a procedure.
U.S. Published Patent Application 2003/0130668 A1 (Nieman) describes a method and apparatus for remotely cannulating a body part, such as a heart. The method and apparatus are endoscopic, i.e the instruments are mounted on the end of a long flexible member and inserted into the body through a trocar, i.e., a sharply pointed surgical instrument contained in a cannula. The endoscopic procedure is complicated. After the device is placed at or near the apex of the heart, the surgeon or some other controller performs at least 13 separate steps to secure the cannula in the heart wall. An attachment ring (which includes an apical ring and a locking stem) is sutured to the heart wall, and subsequently the cannula is connected to the attachment ring as a separate step. Because the procedure is endoscopic, imaging means (e.g., fluoroscopy) is used to place a balloon at the correct depth within the ventricle to provide occlusion.
The complex endoscopic procedure disclosed in Nieman appears to require that the cut tissue core be removed from the body prior to advancing the cannula to the heart wall. Further, Nieman appears to provide two mechanisms for placing the cannula in the heart wall. One such mechanism is to create a hole that is large enough to easily slide the cannula into the hole. This does not provide a tight fit between the cannula and cored heart wall to prevent blood loss from the cored heart wall and from the ventricle and relies entirely upon the sutured attachment ring to achieve hemostasis thus providing a period of time during which there could be great losses of blood. The second mechanism is to achieve a tight (interference) fit between the cannula and cored hole. However, such a tight fit requires substantial axial and torsional forces to be applied to the cannula. The flexible endoscopic instrument disclosed in Nieman cannot provide such forces to be transmitted.
U.S. Patent Publication No. 2004/0162608 (Haverich) discloses a method and apparatus for implanting a conduit into the wall of a heart. As illustrated in FIG. 8A, Haverich shows a conduit on a cutter that has a “corkscrew driver” with a coil. The corkscrew is rotated to cause the cutter to penetrate through the myocardium. However, substantial axial force is required to cleanly penetrate the myocardium, and such force is not easily applied by a corkscrew. Further, the pointed tip of the corkscrew can damage other areas of the heart wall (e.g., the septum) while applying axial force and rotation. Haverich discloses a balloon used for hemostasis. However, the balloon is a separate instrument that cannot be combined with the corkscrew.
U.S. Patent Publication No. 2002/0045846 (Kaplon) discloses a device similar to Haverich except that a trocar is used to penetrate the organ wall instead of a cutter with corkscrew. No tissue plug is formed with a trocar. Use of a trocar makes it difficult to achieve hemostasis during a procedure on a beating heart. To address this, rigid conduit 18 is inserted through the connector 16 after the connector is implanted with the trocar and sewn into place. Connector 16 does not appear to penetrate the heart wall. Connector 16 has a built-in valve to prevent blood loss after the trocar is removed and until conduit 18 is inserted.
A connector conduit according to the preferred embodiment includes a rigid apical connector portion which will serve to provide egress from the left ventricle (such as from the apex or lateral wall), a flexible conduit portion which will carry blood from the connector to the arterial system (such as to the descending thoracic aorta or the ascending thoracic aorta), and the aortic valve itself, which will be situated somewhere within the conduit. The present invention primarily addresses implantation of an apical connector with an attached length of conduit, referred to herein as the connector conduit (or connector). The connector conduit is implanted using an applicator. Although this discussion focuses primarily on the apex of the left ventricle, it is understood that the present invention can be used to implant a connector conduit to any wall of the left ventricle or other hollow organ.
As described earlier, the surgeon conventionally uses a cork borer to cut a tissue plug from the ventricle wall. Once the tissue plug is removed, the surgeon must attempt to occlude the resulting hole, such as with a finger, a balloon or some other occlusion means, until the connector conduit is inserted. Despite attempts to occlude the resulting hole, substantial blood loss is inevitable. Cardiopulmonary bypass is used to reduce blood loss.
An object of the present invention is to integrate the cork borer and connector conduit to form a system in which the connector conduit is inserted into the ventricle wall as the tissue plug is being created, thereby eliminating the need for a separate occlusion means and greatly reducing blood loss. Such integration may be achieved by mounting the connector conduit directly onto the outer diameter of a coring element or integrating the cutter and the connector conduit, which cuts the tissue plug and occludes blood flow through the inner diameter. In this way, the cross sectional area for blood loss is reduced to the gap between the coring element and connector conduit.
Another object of the present invention is to combine the coring element with other features to form a complete applicator for securing the connector conduit into the ventricle wall. These features may include a mounting element and a handle element. The mounting element is an extension to the coring element that serves to add axial length to the coring element onto which the full length of the connector conduit may be mounted. The mounting element may be of the same diameter as the coring element. The handle element provides a grip to facilitate the necessary positioning, twisting and pushing force necessary to cut the tissue plug and to insert the connector into the ventricle wall. The handle could have a pistol handle shape, for example.
Another object of the present invention is to provide the option for additional features for the complete applicator system for securing the connector conduit into the ventricle wall, particularly at the apex. These additional features may include a retractor element and a quick connect coupling element.
The retractor element may have an expanding element for: 1) shaping the apex of the ventricle into a preferred shape for cutting the tissue plug, 2) providing a backing surface for the coring element in order to sandwich the heart wall between the coring element and expanding element, 3) pulling the tissue plug to within the coring element, and/or 4) ensuring that the tissue plug remains inside the coring element. The expanding element could be a liquid-inflated balloon, sponge, or a mechanically-operated umbrella, as examples.
The expanding element is mounted onto the retractor element, and the retractor element is slide-ably mounted within the coring element. A coupling element, such as a compression spring, provides the force to move the retractor element relative to the coring element. The retractor element may be designed to prevent relative rotation between the expanding element and coring element, thereby reducing the likelihood of damage to the expanding element. The retractor element may also include a section of increased diameter that abuts the outer heart wall to prevent premature or undesired cutting of the ventricle wall by preventing contact between the coring element and ventricle.
Another object of the present invention is to provide an expanding element that has a similar look and feel as the conventional procedure. For example, the expanding element may be a balloon. A syringe element may expand the expanding element to a predetermined level by inflation with a liquid. To minimize the space required for the syringe, the balloon may be designed specifically to require minimal inflation volume while still performing the necessary functions of the expanding element. In addition, a filling element of the applicator may provide the means to fill the syringe element and balloon from an external liquid source and to provide the means to purge air from the expanding element.
Another object of the present invention is to provide a connector conduit that has many of the features of the conventional apical connector (e.g., Medtronic™ apical connector) and includes additional features to make it compatible with the applicator and the surgical procedure. Additional features to make the connector conduit compatible with the applicator include 1) an ability to straighten the connector conduit from a bent configuration so that it will slide onto a straight mounting element, 2) a modified leading edge on the connector to ease insertion into the heart wall, and 3) a clamping element that includes portions of both the connector conduit and the applicator which serves to lock the connector conduit to the applicator in a predetermined position and to facilitate applying the twisting and pushing force necessary to insert the connector.
An additional feature of the connector conduit to make it compatible with the surgical procedure is a quick connect coupler to expedite attachment of the connector conduit to the remainder of the prosthesis, which includes the prosthetic valve. The quick connect coupler is necessary to prevent a long time delay between implanting the connector conduit into the ventricle and achieving blood flow through the complete prosthesis. Such quick connect coupler may consist of a first part that is attached to the connector conduit and a second part that is attached to the remainder of the prosthesis, which includes the prosthetic valve.
An additional feature of the connector conduit to make it compatible with the surgical procedure is to provide a length of conduit that may be collapsed, such as with an occlusion clamp, to prevent blood flow through the connector conduit before the quick connect coupler is connected and the surgeon is ready to allow blood flow through the complete prosthesis.
In one configuration of the invention, expansion of the expanding element and the position of the retractor element are controlled independently by the surgeon. For example, if the expanding element is a balloon connected to a syringe, the volume of liquid in the balloon is controlled by the position of the plunger inside the syringe. Similarly, a bolt may be used to control the position of the retractor element relative to the coring element. In this configuration, the surgeon must independently control the positions of the syringe plunger and the retractor element bolt.
Another configuration of the present invention provides a sequencing element (such as a cam mechanism) that ensures that critical steps of the procedure are performed in the proper sequence. The sequencing element synchronizes expansion of the expanding element with position of the retractor element. The sequencing element includes a sequencing bolt. The surgeon uses one hand to hold the applicator handle and the other hand to slide the sequencing bolt. In this way, independent control of the expanding and retractor elements is eliminated. Independent positions of these components are not user driven; rather, positions of these components are synchronized by the sequencing element. One example of a sequencing element is described next; however, it is understood that a sequencing element may be used to control fewer steps or additional steps of securing the connector conduit into the ventricle wall.
The system is set up with the connector conduit mounted onto the applicator and with the retractor fully extended. The procedure begins by making a small knife wound in the apex and pushing the retractor element (with fully-deflated expanding element) through the heart wall and into the ventricle. The surgeon slides the sequencing bolt from a first position to a second position. Once the sequencing bolt is in the second position, the surgeon may release the sequencing bolt. The sequencing element ensures that this sliding motion serves to first expand the expanding element and, after the expanding element is fully expanded, to release the retractor element so that the retractor element can move the expanding element relative to the coring element. The surgeon may now use the handle to apply twisting and pushing force to place the connector conduit into the ventricle wall. During this time, the sequencing element simultaneously coordinates:
a. application of compressive force between the expanding element and the coring element, thereby sandwiching and shaping the heart wall for cutting the tissue plug,
b. the coring element to cut a hole in the ventricle wall, thereby creating a tissue plug,
c. insertion of the connector conduit into the hole, and
d. the retractor element to retract the tissue plug from the hole into the coring element.
Once the tissue plug is created, the sequencing element partially reduces the diameter of the expanding element so that the expanding element can enter the inner diameter of the coring element while remaining of large enough diameter to prevent the tissue plug from sliding off of the retractor element. This change in diameter of the expanding element occurs automatically to a pre-set intermediate diameter without attention from the surgeon; Once the surgeon has placed the connector conduit at the desired position within the ventricle wall, the applicator may be removed.
In a preferred configuration, the connector conduit is a fabric (e.g., Dacron) covered device that is specifically designed for insertion into the wall of the left ventricle, such as at the apex. It contains a structural frame, a sewing flange (or suture ring) for attachment to the heart, and a standard fabric (e.g., Dacron) flexible vascular graft that extends through the lumen of the entire length of the structural frame and for some additional length beyond. An outer fabric may also cover the outside of the structural frame. The components of the connector conduit are interconnected, such as with polyester thread. The fabric may include orientation marks, such as a line along the length of the conduit. In addition, a quick connect coupling may be used to attach the connector conduit to the remainder of the prosthesis, which includes the prosthetic valve or ventricular assist device, as examples.
A function of the structural frame is to provide mechanical integrity, i.e., rigidity, for the connector conduit. The structural frame may include a leading edge, a cage, a bend, and a holder. The leading edge is the first portion of the structural frame to be pushed through the heart wall. To minimize effort needed to push the connector through the heart wall, such leading edge may be tapered and/or beveled, for example. The cage is the portion of the structural frame that resides within the heart wall. The bend is the portion of the structural frame that holds the conduit in a preferred shape to direct blood flow from the left ventricle to the aorta, as described next in more detail. The holder is the portion of the structural frame that provides a means of mechanical connection between the connector conduit and applicator.
The bend in the structural frame may be any appropriate angle (such as 90 degrees) to properly direct the conduit from the ventricle to the portion of the aorta where the conduit is to be connected. For example, the bend in the structural frame may be around 90 degrees if the conduit is to be connected to the descending thoracic aorta, or a larger angle bend may be used if the conduit is to be connected to the ascending thoracic aorta, for example. As described next, such bend may be flexible or rigid.
In one embodiment, the bend of the structural frame may be flexible. For example, a set of equally-spaced circular rings mounted perpendicularly on a spine could form a bend that can flex to a range of angles. The circular rings provide radial support to prevent collapse of the conduit due to external forces. The spine may be at the outer radius of the bend or at the inner radius of the bend, as examples. In this embodiment, the bend can be straightened out from a preferred angle such that a mounting element of the applicator may be inserted straight through the lumen of the connector. Upon removal of the mounting element, if the bend is constructed of a material with a relatively high modulus of elasticity (e.g., PEEK), the connector returns to its bent configuration. If the bend is constructed of a material with a relatively low modulus of elasticity (e.g., polypropylene, polyethylene), the connector forms the bent configuration only when an external force is applied, such as by a bending means. Such bending means could involve pulling on threads that are weaved through the circular rings so that the bend is formed when the threads are pulled, for example. When the bend is at the preferred angle, the user may tie or crimp the threads together, for example, thereby preventing straightening of the bend. Such bending means allows the user to select any one of a plurality of possible bend angles as the preferred angle. Such bending means may also be used with a bend constructed of a material with a relatively high modulus of elasticity, such as to prevent straightening beyond the preferred angle.
In another embodiment, the bend of the structural frame may be rigid. In this embodiment, since the bend cannot be straightened out, the bend must include a port such that the mounting element of the applicator may be inserted through such port and through the lumen of the cage. In this embodiment, the conduit must include a branch of additional conduit to form a Y. Such additional branch of conduit is coaxial with the cage for mounting the connector conduit onto the applicator. Once the connector conduit is implanted into the heart wall and the applicator is removed, the branch of conduit is occluded, such as by sewing or stapling the conduit closed, for example. The branch is then removed, such as by cutting with scissors.
In another embodiment of the connector conduit, a quick connect coupler may be used to attach the connector conduit to the remainder of the prosthesis, which includes the prosthetic valve. The complete prosthesis may be divided into two parts: a first part that includes the prosthetic valve with lengths of conduit attached to both the upstream and downstream sides of the prosthetic valve and a second part that includes the connector conduit. The quick connect coupler allows the surgeon to rapidly connect said first part to said second part. In this way, the surgical procedure may be performed by first attaching said first part of the complete prosthesis to the aorta. Then, after the connector conduit is secured into the ventricle wall, the quick connect coupler allows rapid completion of the flow circuit to minimize the time between insulting the heart by cutting the hole and reducing the work load on the heart by allowing blood flow through the prosthesis.
An applicator is used to implant the connector conduit into the ventricle wall. In a preferred embodiment, the applicator provides mechanical support on the surfaces of both the inner diameter and the outer diameter for some portion of the fabric-covered structural frame. Such support may be necessary to avoid unwanted distortion or movement of the structural frame while the connector conduit is being implanted through the heart wall. For example, the mounting element of the applicator, which is inserted straight through the lumen of the connector, may provide mechanical support (such as radial support) on the inner-diameter surface to reduce distortion of the structural frame during implantation. On the outer-diameter surface, the applicator may include a concentric tubular structure, referred to as the pushing element. The pushing element provides mechanical support (such as radial support) on the outer-diameter surface of the structural frame to reduce distortion during implantation. In a preferred embodiment, the mounting element and the pushing element are rigidly connected.
In a related embodiment, an indexing means provides an interface between the pushing element and connector conduit that may prevent or greatly reduce rotation and/or axial movement of the connector conduit relative to the pushing element. As such, rotary or axial force applied to the pushing element is transmitted to the connector conduit through the locking means. An effective locking means may incorporate portions of the pushing element, mounting element and connector conduit. For example, the indexing means may include a slot-and-key arrangement that 1) positions the connector conduit at a preferred angle relative to the pushing element thereby orienting the bend in the structural frame, 2) prevents axial and rotary motion of the connector conduit relative to the pushing element, and 3) allows the connector conduit to be easy mounted onto and released from the applicator. Such indexing means may include a pushing element with an adjustable diameter that allows both rigid mounting and unhindered release of the connector conduit. Such indexing means may also include a connector conduit with a holder that locks to the pushing element, such as with a slot-and-key arrangement and/or with a tight friction fit, as examples. Such holder may be sandwiched firmly between the mounting element and pushing element.
In a preferred configuration, the mounting element extends from a coring element that shares the same axis and has the same outer diameter as the mounting element. The coring element is used to cut a hole into the heart wall. Such coring element could consist of a thin-walled tube, the leading edge of which has been sharpened or serrated. The inner diameter of the connector conduit could fit snugly on the outer diameter of the coring element and mounting element. In use, the coring element could produce a hole in the heart wall that is smaller than the outer diameter of the connector conduit, thereby producing a snug fit.
In a related embodiment, a handle may be rigidly attached to the pushing element. The handle may be at a substantially right angle after the manner of a pistol grip, for example. Such a handle attachment provides a more effective method of applying the insertion force and back-and-forth rotation needed to implant the connector conduit.
In a preferred configuration, located concentrically within the mounting element is a retractor element consisting of a generally tubular structure having a pointed end that is inserted through the left ventricle wall. The tubular structure could be rigid. In a preferred embodiment, the pointed end of the retractor element could be a blunted point. In this way, after a small knife wound is made in the epicardium (outer surface of the heart), the blunted point could enter the knife wound and divide muscle fibers to penetrate the myocardium and left ventricle chamber. A purpose of the blunted point is to reduce the likelihood of damage should the point unintentionally contact other areas of the inner wall during use. In an alternative embodiment, the retractor element could include a very sharp pointed end being capable of producing its own entrance hole into the wall of the heart. Alternately, it could have a blunted point that would simply follow a previously created hole through the entire thickness of the ventricle wall. If so desired, the tubular structure of the retractor allows use of a guide-wire to follow a previously created hole.
Near the pointed end of the retractor element is an expanding element, such as an inflatable balloon, an unfolding umbrella-like construction, an expandable collar, or similar structure. Once inside the ventricle, the expanding element is expanded from an initial diameter that may approximate the outer diameter of the retractor element to a second diameter. In a preferred configuration, the expanding element expands to a second diameter that is larger than the outer diameter of the coring element. The expanding element expanded to its second diameter seats snugly against the inside wall of the ventricle. Functions of the expanding element may include 1) expanding symmetrically to shape the inner wall of the ventricle into a preferred shape for cutting the tissue plug, and 2) fully retracting to within the coring element while remaining at least partially expanded.
A first function of the expanding element is symmetric expansion, which provides at least two benefits. The first benefit is related to the variable, cone-shaped geometry of the left ventricular chamber near the apex. Symmetric expansion of the expanding element to a diameter that is larger than the outer diameter of the coring element effectively flattens out the ventricle wall in the vicinity of the apex so that the ventricle wall is more perpendicular to the sharpened leading edge of the coring element, thereby allowing the coring element to cut through the entire thickness of the ventricle wall. The tubular structure of the retractor element must resist the radial reaction forces from the ventricle walls. The second benefit of symmetric expansion is to ensure contact between the expanding element and the leading edge of the coring element along its entire circumference as the tissue plug is formed. Asymmetric expansion of the expanding element can result in formation of a plug with hanging attachments to the left ventricle wall.
A second function of the expanding element is to fully retract and retain the plug within the coring element after the plug is cut. Such full retraction ensures that the applicator will slide out of the connector conduit (after the connector is implanted) without the plug and expanding element coming into contact with the inner diameter of the connector conduit. Such contact could increase the force required to remove the applicator from the connector conduit and could possibly result in debris from the removed plug being deposited on the inner diameter of the connector conduit. In addition, the expanding element must remain at a large-enough diameter after being retracted to within the coring element to ensure that the plug cannot slide off the end of the retractor element.
In a related embodiment, this second function could include a coupling element that forces the retractor element to retract within the mounting element. In a preferred configuration, the coupling element could be a compression spring, for example. In this configuration, the retractor element could be slide-ably connected to the mounting element by means of the compression spring. The force produced by the compression spring tends to pull the expanding element snugly against the inside wall of the ventricle and to pull the tissue plug into the coring element after the tissue plug is detached from the ventricle. Alternatively, the user could manually provide the necessary force to retract the retractor element to within the coring element.
In a preferred embodiment, the expanding element can be: 1) initially at a first diameter that approximates the outer diameter of the retractor element, 2) expanded to a second diameter that is larger than the outside diameter of the coring element, and 3) then reduced to a third diameter that is smaller than the inside diameter of the coring element but larger than the outer diameter of the retractor element. Inflation to the second diameter accommodates the first function of the expanding element (described above), and reducing to the third diameter accommodates the second function of the expanding element (described above).
In a preferred embodiment, the expanding element is a balloon. The balloon may be inflated using an access means, such as a plunger in cylinder configuration (like a syringe) connected to the balloon by a flow passage, such as a channel integrated into the retractor element. An appropriate fluid to inflate the balloon could be saline, for example. The balloon material should be selected to best perform the functions of the expanding element. Polyurethane is a preferred material. Polyurethane is an elastic material that allows a balloon to be expanded symmetrically to as much as twice the original volume using a hand-held syringe. Such balloons are strong, abrasion resistant, and durable. Use of latex, another elastic material, is less desirable. Latex balloons typically expand asymmetrically, so use of a latex balloon as the expanding element could necessitate a means integrated into the balloon to ensure symmetric expansion. In the present invention, a latex balloon could be inflated to a symmetric diameter as determined by tension rods or sutures, for example, attached to the balloon and the retractor element. Once the tissue plug is formed, the plunger could be displaced to reduce the size of the balloon to allow retraction into the coring element. A means to prevent damage to the latex balloon by the coring element may be used. Alternatively, the balloon may be constructed of polyethylene terephthalate (PET; trade names include Dacron and Mylar), which is a non-elastic material. Balloons made of PET may be symmetrically inflated to higher pressures without appreciable change in the balloon volume.
In one configuration of the present invention, expansion of the expanding element and the position of the retractor element are controlled independently by the surgeon. Consider the example of using a balloon as the expanding element. Inflation of such balloon could be fully controlled by the surgeon, such as by using a finger to displace a plunger inside a cylinder. In such case, the surgeon could inflate the balloon to any volume up to the maximum volume of the plunger/cylinder. Also in this configuration, the position of the slide-able retractor element relative to the coring element may be independently controlled by means of a bolt attached to the retractor element that passes through an indexed slot in the mounting element. In a preferred embodiment with the mounting element rigidly connected to a pushing element, the indexed slot could be in such pushing element. As the bolt is moved from one indexed position in the slot to another, the retractor is advanced or retracted relative to the coring element. In a preferred configuration with compression spring coupling between the retractor element and coring element, an indexed slot with the retractor element fully advanced (ready for insertion into the left ventricle wall) could be used. The bolt could then be manually released from the indexed slot after inflating a balloon on the retractor element. The compression spring would then pull the balloon firmly against the inner heart wall, thereby sandwiching the heart wall between the balloon and coring element.
Independent control of the expanding element and retractor element could require increased surgeon training to ensure operation of these elements in the proper sequence. Alternatively, various latching or locking means could be used. For example, once the balloon has been inflated to a preset maximum volume, a latching means could lock the plunger into place, thereby preventing unintentional deflation of the balloon. If necessary, deflation to an appropriate volume for retraction into the coring element could be automatically triggered when the retractor element reaches a preset position during retraction. Alternatively, inflation and deflation of such balloon to preset maximum and reduced volumes could occur automatically, such sequence being initiated by pressing a spring-loaded trigger that displaces the plunger, for example. In addition, a safety latch or other means could prevent manual release of the bolt until the expanding element is fully expanded. These separate latching or locking means could result in a complicated mechanical configuration.
In a preferred configuration of the present invention, a sequencing element, such as a cam mechanism, is used to coordinate expansion of the expanding element with position of the retractor element. Control of the expanding element and control of the retractor element position are coordinated so that the surgeon need only move a single sequencing bolt to control both the expanding element and the retractor element. The specific actions of the expansion element and retractor element that are controlled by the sequencing element may be chosen by the device designer to best accommodate the degree of control preferred by surgeons.
In one embodiment of a preferred configuration that includes a sequencing element, the cylinder used to inflate/deflate the balloon (the syringe cylinder) may be integrated into the retractor element. Thus, the syringe cylinder, retractor element, balloon, and flow passage connecting the syringe cylinder to the balloon are integrated into a single component, referred to as the retractor assembly. The plunger used to inflate/deflate the balloon (the syringe plunger) may include a sequencing bolt extending radially from the plunger axis. Such sequencing bolt also extends radially through a slot in the syringe cylinder. As such, the slot in the syringe cylinder limits axial movement of the plunger in the syringe cylinder. By having a plurality of circumferentially interconnected slots of various axial lengths in the syringe cylinder, the degree of balloon inflation may be controlled by moving the sequencing bolt to a preferred axial slot. Synchronization of balloon inflation/deflation with motion of the retractor assembly relative to the pushing element (which is rigidly connected to the mounting element) may be achieved with two cam slots in the pushing element, for example. The first cam slot controls motion of a cam follower rigidly attached to the retractor assembly, thereby controlling the position of the retractor assembly relative to the pushing element. The second cam slot synchronizes inflation/deflation of the balloon relative to the position of the retractor assembly within the pushing element. The sequencing bolt serves as the cam follower in the second cam slot. Safety features may be integrated into the design of the cam mechanism. For example, the cam and follower can be designed to prevent movement of the retractor assembly relative to the pushing element (which is rigidly connected to the coring element) until the balloon is fully inflated.
Various other features may be included to ensure safety and proper use of the connector conduit with applicator. For example, a port with a two-way valve may be integrated into the plunger/cylinder with balloon system to allow for filling with fluid and removal of air. As another example, a mounting tool may be used to mount the connector conduit over the coring element without damage to the fabric. As another example, a folding tool may be used to squeeze fluid from the balloon and to fold the balloon for use. As another example, the mounting tool and folding tool may be integrated into a single tool.
The invention facilitates procedures using an integral device in which the various steps are preformed in a coordinated, i.e. sequenced manner. This renders the procedure simple and safe and reduces the likelihood of tissue damage or other complications. Other features and advantages of the invention will be apparent from the detailed description and from the claims.
In another form of the present invention, there is provided an apparatus and method for attaching a conduit to a hollow organ.
In an additional form of the present invention, there is provided an apparatus and method for attaching a left ventricular assist device (LVAD) to a heart.
In a preferred form of the invention, there is provided apparatus for attaching a left ventricular assist device (LVAD) to a heart, the apparatus comprising:
a connector conduit comprising:
In another preferred form of the invention, there is provided a system for providing pumped bloodflow, said system comprising:
a connector conduit comprising a distal end, a proximal end and a lumen extending from said distal end to said proximal end;
an applicator for forming a hole in a heart and inserting said distal end of said connector conduit into the hole formed in the heart; and
an LVAD having a distal end and a proximal end, wherein said distal end of said LVAD is configured to be inserted and secured to said proximal end of said connector conduit.
In another preferred form of the invention, there is provided a method for connecting a left ventricular assist device (LVAD) to the heart, the method comprising:
forming a hole in the heart;
connecting a distal end of a connector conduit to the hole formed in the heart;
connecting an LVAD to a proximal end of the connector conduit; and
permitting fluid to pass from the heart through the LVAD.
These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein:
The connector-conduit with applicator of the present invention is best described as consisting of five major parts: a connector-conduit, a retractor, hole forming device such as a coring element, a pushing component, and a handle. A fabric material pleated conduit of a type common and well known in the field is permanently fixed to the inner surface of a rigid connector to form the connector-conduit. The conduit extends from the forward edge of the connector and continues beyond the connector, as a flexible portion, for some distance.
The connector-conduit includes a rigid portion defined by an internal support structure made of a suitably flexible material that is preferentially biased to assume a bent configuration (such as a right angle) upon removal of restraining forces. In one embodiment, the connector internal support structure is covered with fabric, such as knitted or woven Dacron, for example. A suturing ring is integrated into the covering fabric and provides a suitable flange for suturing the connector to the surface of the heart. The leading edge of the connector is tapered to facilitate insertion of the connector-conduit component. The “rigid” portion is rigid enough to facilitate insertion as described below and to maintain the hole in an open position. However, the rigid portion can be flexible. Accordingly, the term “rigid” as defined herein means relatively rigid and can include flexibility.
As shown in
The leading edge of structural frame 101 is a taper 110 which allows for easy insertion of the connector through the ventricle wall. The material of the structural frame 101 could be a shape memory alloy (e.g., Nitinol), plastic, or other similar biocompatible material.
Referring to
An interference fit between connector surface 22 and the hole created by the coring element 40 is necessary to reduce bleeding from the cut myocardial surface and to reduce blood leakage from the left ventricle. The amount of such interference fit is the difference between the diameters of the hole created by the coring element 40 and the outer surface of the connector 22.
In a preferred embodiment of the device, the coring element 40 has an outer diameter that closely matches the inner diameter of the connector-conduit 32. Such construction allows removal of the coring element 40 through the connector-conduit 32 while presenting only a small blood pathway between these two elements. Such construction is intended to minimize blood loss from the left ventricle when the coring element 40 has completed its cut.
Referring to
Referring to
Also shown in
As the surgeon applies force and rotation using handle 90, compression spring 70 continues to displace retractor element 50. When retractor element 50 is fully retracted, the surgeon can rotate bolt 72a into index 84b to lock the retractor element 50 in place. Moreover, when retractor element 50 is fully retracted, the expanding element 56 is also fully retracted into coring element 40, indicating that the tissue plug has been successfully removed from the left ventricle and is within the coring element 40.
Referring to the embodiment of
A holder 130 is formed at one end of cage 120 and may be used to grasp the connector during implantation. As will be described further herein, holder 130 can have a slot-and-key configuration with the applicator. As such, the holder 130 utilizes holder slots 431 or a holder button 430 (
Referring again to
The structural frame of
One embodiment of a bending means is shown in
As discussed previously, structural frame 101 may be constructed with a fixed bend 145, as shown in
Referring to
In use, the applicator of the present invention is used to implant the connector conduit 100 into the ventricle wall or other organ wall.
In further accordance with a preferred embodiment, a locking means provides an interface that prevents movement of the connector conduit 100 relative to the pushing element 300. Such locking means may include components that are integral with the pushing element 300, connector conduit 100, mounting element 200, and coring element 210.
When squeeze ring 410 is positioned at or near notch 421 as shown in
In accordance with a further embodiment of the present invention, a retractor component/element 500 with a generally tubular structure is located concentrically within the mounting element 200, as shown in
Retractor element 500 is held concentric within the mounting element 200 by centering plug 220 and sliding plug 521. Centering plug 220 is rigidly attached to mounting element 200, and sliding plug 521 is rigidly attached to tubular body 520. Since radial force from the heart wall tends to deflect the expanding element 530, tubular body 520 must have a sufficient stiffness to substantially resist such deflection. Such deflection may also be reduced by limiting the axial distance between the expanding element 530 and centering plug 220.
A coupling element, such as compression spring 540, slideably couples retractor element 500 to mounting element 200. Compression spring 540 biases retractor element proximally to ensure that expanding element 530 seats snugly against the inside wall of the ventricle to shape and partially flatten the ventricle wall (particularly at the apex) so that coring element 210 may cut perpendicular to the ventricle wall. Once the tissue plug is cut from the ventricle by coring element 210, spring 540 pulls the tissue plug fully within the coring element 210. In the preferred embodiment, expanding element 530 is a balloon in the shape of a circular toroid.
In operation, retractor bolt 522 is positioned in index 321 until the retractor element 500 is fully inserted into the ventricle and expanding element 530 is fully inflated. At that time, retractor bolt 522 is manually released from index 321, which allows compression spring 540 to retract retractor element 500 until expanding element. 530 contacts the inside wall of the ventricle. A damping means (not shown) may be included to prevent sudden retraction of the retractor element 500 upon release from index 321. Also not shown is a safety latch or other means to prevent manual release of the retractor bolt 522 until the expanding element 530 is fully expanded. As the surgeon applies force and rotation using handle 310, compression spring 540 continues to displace retractor element 500. When retractor element 500 is fully retracted, expanding element 530 is also fully retracted to within coring element 210, indicating that the tissue plug has been successfully removed from the left ventricle and is within the coring element 210.
In operation, retractor cam slot 730 controls the motion of cylinder 562 within the pusher assembly. As shown in
Referring to
Before implanting the connector conduit 100 into the ventricle wall, the portion of the prosthesis that includes the prosthetic valve or ventricular assist device, as examples, is connected to the aorta. This portion of the prosthesis also includes the female end of quick connect coupler 180. By implanting this portion of the prosthesis first, the time between insulting the heart by cutting a hole and beginning blood flow through the complete prosthesis is minimized.
A template with similar dimensions as connector conduit 100 is placed on the apex of the heart, and a marker is used to trace the circular outline of the connector onto the apex, in the planned location of insertion. Multiple (8 to 12) large pledgeted sutures (mattress sutures) of for example, 2-0 prolene, are placed in the apex surrounding the marked circle. With the connector conduit 100 loaded in the applicator of
Connector conduit 100 is now fully implanted. The sutures are tied, and hemostasis is checked. Additional sutures may be placed if needed. The locking means (not shown) holding the connector conduit in the applicator is released, and the applicator is partially removed to a position where a clamp can be placed directly on collapsible graft 160a to prevent blood flow through the conduit 160. Once the clamp is in place, the applicator may be completely removed from connector conduit 100. The male and female ends of quick connect coupler 180 may now be connected. Umbilical tape 187 may be tied around graft extension 186a to reduce any blood leakage, and stay sutures may be used to secure graft extension 186a to outer fabric 165. Once the flow passage of the prosthesis is purged of air, the clamp may be released to allow blood flow through the prosthesis. Flexible bend 140 is formed by pulling threads 143 and tying a knot. The connector conduit 100 is now fully implanted.
As illustrated in
In the preferred embodiment described above, the expansion element is a balloon. However, an alternative expansion element, in the form of an umbrella mechanism, is illustrated in
The foregoing description discloses an apparatus and method for forming a hole in a hollow organ and attaching a connector conduit to the hollow organ. By way of example, but not limitation, the foregoing description discloses an applicator for performing aortic valve bypass surgery (AVB), which may be otherwise referred to as apico-aortic conduit, wherein a hole is formed in the left ventricle and a bypass conduit is attached to the left ventricle. It should also be appreciated that the applicator could be used to attach other conduits or other devices to a heart or other organ. In one embodiment, the present invention uses the applicator disclosed above to attach a left ventricular assist device (LVAD) to a heart.
Left ventricular assist devices (LVADs) are blood pumps which assist weak or failing hearts in performing circulatory functions. Commercially available LVAD pumps are manufactured by Heartware International Inc. of Framingham, Mass. and Thoratec Corporation of Pleasanton, Calif., for example. The latest generation of LVAD pumps are small in size and the blood flow is generally in-line with the pump axis. The LVAD pump consists of a housing, an inlet and an outlet for blood flow, an electric motor rotating an axial flow impeller at high speed, and a power connection.
The current procedure for installing an LVAD pump requires open-heart surgery. The installation of LVAD pumps is generally done while the patient is connected to a heart-lung bypass machine. Once the patient's chest has been opened, typically through a median sternotomy, the apex of the heart is exposed. Cardiopulmonary bypass (CPB) is initiated to pump and oxygenate the patient's blood during the procedure. Typically, cardioplegic arrest is induced. The surgeons then attach an LVAD sewing ring to the left ventricle wall of the heart near the apex using sutures. An incision is made through the heart wall centered on the sewing ring to allow for the inlet of the LVAD pump to be inserted into the heart. If desired, a coring tool can be inserted through the sewing ring and used to core out a tissue plug so that the inlet of the LVAD pump can be inserted into the cored out portion of the heart. Alternatively, the inlet of the LVAD pump itself can be used to force open the incision made in the heart wall. The LVAD pump is secured to the sewing ring using a mechanical clamp or sutures, depending on the design, with an outflow graft extending therefrom. The outflow graft of the LVAD pump can then be attached to the ascending aorta or to the descending aorta. The aorta is side clamped, an aortotomy is performed, and the conduit is sutured to the aorta. The side clamp is partially loosened to verify hemostasis, and then removed entirely.
After the implantation procedure has been completed, a de-airing procedure is performed to vent air from the left ventricle and from the LVAD pump. After de-airing, the LVAD pump is set to operate normally as the patient is weaned off of CPB. The patient's chest is then closed.
One problem associated with the current method of installing an LVAD pump in the heart is that use of a heart-lung machine carries well-known risks to the patient. By way of example, embolic events resulting in short to long term mental impairment are possible. In the current procedure for installing an LVAD pump, the heart-lung machine is needed because current devices and techniques cannot maintain hemostasis during the coring and insertion process. Without hemostasis, catastrophic blood loss can occur during the coring and insertion process.
Consequently there is a need for an improved apparatus and method that enables installation of an inlet of an LVAD pump into the left ventricle on a beating heart without use of a heart-lung machine.
The present invention provides an apparatus (which is sometimes referred to as an “LVAD connecter assembly”) and a method for using an applicator, such as the applicator disclosed in
More particularly, the LVAD connector assembly of the present invention is configured for use with an applicator which simultaneously cores and captures a tissue plug while inserting a conduit connector into the cored hole. By way of example but not limitation, the LVAD connector assembly can be installed in the left ventricle wall near the apex of the heart with the applicator described in FIGS. 3-9, 16A-24 and 26A-26D of U.S. Pat. No. 7,510,561 or in FIGS. 2-7D of U.S. Pat. No. 7,799,041, which applicators are sometimes referred to herein as the “Correx Applicator”. U.S. Pat. Nos. 7,510,561 7,799,041, are hereby incorporated herein by reference.
Looking now at
Connector conduit 1005 comprises a sleeve conduit 1015, a sewing ring 1020, a sleeve fixation ring 1025 (
LVAD pump 1010 comprises a distal end 1040 having an inlet 1045 and a proximal end 1050 having an outlet 1055. An outlet graft (not shown) can be attached to proximal end 1050 at outlet 1055.
In a preferred embodiment, sleeve fixation ring 1025 is bonded to sleeve conduit 1015 using an implantable adhesive such as Applied Silicone 40076 or NuSil MED-2000. Other attachment methods may also be used such as threaded fasteners, crimps, snap fits, thermal or ultrasonic welding, or an interference fit. Sleeve fixation ring 1025 retains and seals one end of tapered sleeve 1030. The fabric covered sewing ring 1020 is sutured to sleeve conduit 1015. The distal end of tapered sleeve 1030 is fixed to outer collar 1035 using suture and/or adhesive, for example.
LVAD pump 1010 slides into outer collar 1035 and is locked in place (as shown in
To complete the connection of LVAD pump 1010 into connector conduit 1005, cross clamp 1030 is removed, exposing the entire lumen of connector conduit 1005 and LVAD pump 1010 to the heart's blood pressure. LVAD pump 1010 is then pushed axially (i.e., towards the heart), into connector conduit 1005. During axial movement of LVAD pump 1010, tapered sleeve 1030 begins to turn inward, starting at the point where tapered sleeve 1030 attaches to outer collar 1035 (see
After LVAD pump 1010 is completely inserted into connector conduit 1005, a clamp mechanism 1065 of sleeve conduit 1015 is tightened to hold connector assembly 1000 in the final configuration shown in
In a preferred embodiment, sleeve conduit 1015, sleeve fixation ring 1025, outer collar 1035 and LVAD pump 1010 are fabricated of metal, preferably an implant grade of titanium. The outer surface of sleeve conduit 1015 is suitably textured to promote ingrowth.
Tapered sleeve 1030 is preferably dip-molded from an implantable polyurethane such as Lubrizol 3575A. A wall thickness of 0.006″ for the polyurethane tapered sleeve is preferred. Other types and thicknesses of polyurethane can be utilized depending on modulus and material strength. Other flexible implantable materials such as woven polyester graft, nylon, silicone or polyester can also be utilized.
Sewing ring 1020 is preferable an implant grade silicone rubber (NuSil MED-4840) covered with a knitted polyester graft (Vascutek VP1200K).
A preferred method for installing connector assembly 1000 into the left ventricle using an applicator 1100 will now be described in detail below. By way of example but not limitation, applicator 1100 is the applicator sold by Correx, Inc. of Waltham, Mass. under the name “The Correx Applicator”.
In the preferred method, an aortic anastomosis is first performed to connect an assembly comprising an outflow graft and LVAD pump 1010 to the ascending or descending aorta. For attachment to the ascending aorta, a median sternotomy is required, and, for attachment to the descending aorta, a left lateral thoracotomy is needed. The aortic anastomosis is typically achieved by side-clamping the aorta, performing an aortotomy, and suturing one end of the outflow graft to the slit aorta. The side clamp is partially removed to verify hemostasis, and then removed entirely. The outflow graft is typically cross-clamped throughout this process, and also for the insertion of LVAD connecter assembly 1000 into the left ventricle.
Looking now at
Connecter conduit 1005 is mounted onto applicator 1100 (
Pledgeted mattress sutures 1115 are then attached near the apex of the heart in a circular pattern around where a hole will be cored in the left ventricle. Sutures 1115 are loosely looped through sewing ring 1020 (
Using a scalpel, a stab wound is made at the point where the center of the hole will be located. Knife shroud 1105 is removed, exposing a sharp circular coring knife 1110.
A shaft of applicator 1100 is inserted into the stab wound with a balloon 1125 (
Applicator 1100 is now used to core a hole 1120 in the left ventricle and simultaneously insert sleeve conduit 1015 into cored hole 1120. Applicator 1100, with connector conduit 1005 mounted thereon, is advanced until sleeve conduit 1015 is positioned within the left ventricle and sewing ring 1020 is flush with the epicardium. The cored tissue plug is captured within coring knife 1110 and held there by balloon 1125. Mattress sutures 1115 may be tied off at this point (
Once sutures 1115 are tied off, balloon 1125 is partially deflated. With one hand on sewing ring 1020, the surgeon withdraws applicator 1100 through connector conduit 1005. As the partially-deflated balloon 1125 passes through tapered sleeve 1030, tapered sleeve 1030 may be cross-clamped with clamp 1130 to maintain hemostasis (
LVAD pump 1010 is then aligned with connecter conduit 1005 and inserted into outer collar 1035. Then clamp 1060 is locked onto LVAD pump 1010 so as to secure LVAD pump 1010 to outer collar 1035 (
The volume proximal to cross clamp 1130 is de-aired and cross clamp 1130 (and any additional cross clamps positioned on connector conduit 1005) are removed. Blood can now flow from the left ventricle through LVAD pump 1010. LVAD pump 1010 may now be started and other system checks performed.
Looking now at
At this point, installation of the LVAD connector assembly 1000 is complete. Significantly, hemostasis has been maintained at all times and the heart has remained beating during the installation procedure.
In the foregoing section, the term proximal is intended to mean closer to the surgeon's hand (i.e., further away from the heart), and the term distal is intended to mean further away from the surgeon's hand (i.e., closer to the heart).
In a preferred embodiment tapered sleeve 1030 is cross-clamped just proximal (i.e., further away from the heart) of sleeve conduit 1015. In order to avoid excessive deformation and stress on tapered sleeve 1030, it is beneficial to anchor the distal end of tapered sleeve (i.e., the end of tapered sleeve which is closest to the heart) well inside sleeve conduit 1015.
A further improvement to tapered sleeve 1030 is to form tapered sleeve 1030 with varying degrees of flexural stiffness. Preferably, the portion of the tapered sleeve distal (i.e., closer to the heart) to sleeve conduit 1015 would be relatively flexible so that it folds inward easily. The portion of the tapered sleeve 1030 within sleeve conduit 1015 can be far stiffer and ideally resistant to buckling and folding.
Variable stiffness of tapered sleeve 1030 can be achieved in several ways:
(1) the radial thickness of tapered sleeve 1030 can be made thicker for the portion of the tapered sleeve within sleeve conduit 1015;
(2) axial ribs can be formed (e.g., molded) onto the portion of tapered sleeve 1030 within sleeve conduit 1015;
(3) a material with a higher modulus can be used for the portion of tapered sleeve 1030 within sleeve conduit 1015; and/or
(4) any combination of the foregoing.
In an alternative embodiment of tapered sleeve 1030, the tapered sleeve can be configured to fold outward (instead of inward onto itself as discussed above). After LVAD pump 1010 has been fully inserted within the connector conduit, the portion of the tapered sleeve which remains after the tapered sleeve has been folded outward can be cut off and removed by the surgeon.
In the foregoing section, connector conduit 1005 is used to mount an LVAD to the left ventricle of the heart, however, connector conduit 1005 can also be used for other purposes.
By way of example but not limitation, connector conduit 1005 of the present invention can also be utilized to enable recurring on-pump or off-pump access to the interior of the heart while maintaining hemostasis.
Looking now at
More particularly, in this form of the invention, applicator 1100 is used to insert connector conduit 1005 into the left ventricle in the same manner shown in
When insertable device is no longer needed, the insertable device can be withdrawn from the connector conduit in a manner which is similar to the removal of applicator 1100 from the connector conduit. After the insertable device has been removed, tapered sleeve 1030 is cross-clamped using clamp 1130 (
If it is desirable for connector conduit to remain inserted in the left ventricle (e.g., in order to perform a procedure in the future), a removable plug 1160 can be inserted into the connector conduit in order to seal the connector conduit until access to the left ventricle is needed.
During insertion of removable plug 1160 into the connector conduit, tapered sleeve 1030 remains cross-clamped with clamp 1130. Once removable plug 1160 is inserted into outer collar 1035, clamp 1060 on outer collar 1035 is tightened so as to secure the plug to the outer collar, and then clamp 1130 is removed (
At any time in the future, access to the interior of the heart can be regained by loosening clamp 1065 on sleeve conduit 1015 and sliding outer collar 1035 and plug 1160 out of sleeve conduit 1015. As outer collar 1035 and plug 1160 are removed from the sleeve conduit, tapered sleeve 1030 unfolds and is cross-clamped with clamp 1130. Clamp 1060 on outer collar 1035 is then loosened and plug 1160 removed from the outer collar. An insertable device (e.g., catheter 1150) or an LVAD pump 1010 can now be inserted into outer collar 1035, as discussed above.
Looking now at
One-way valve 1275 is preferably permanently mounted inside sleeve conduit 1215. Connector conduit 1205 is mounted to an applicator (e.g., applicator 1100) so that one-way valve 1275 (i) opens when applicator 1100 passes through one-way valve 1275 when sleeve conduit 1215 is placed onto applicator 1100 for insertion into the left ventricle, (ii) closes to prevent blood loss from the left ventricle when application 1100 passes through one-way valve 1275 as applicator 1100 is removed from sleeve conduit 1215, and (iii) opens when LVAD pump 1010 is passed through one-way valve 1275 as the LVAD pump is inserted into sleeve conduit 1215.
One-way valve 1275 provides two seals which were previously provided by (i) cross-clamping tapered sleeve 1030 with clamp 1130, and (ii) tightening outer sleeve 1035 onto LVAD pump 1010 with clamp mechanism 1060. More particularly, since one-way valve 1275 closes when applicator 1100 is removed from connector conduit 1005, blood is prevented from flowing out of the heart and through the connector conduit prior to the insertion of the LVAD pump into the connector conduit. Accordingly, with this form of the invention, there is no need to cross-clamp the connector conduit after the connector conduit has been inserted into the left ventricle in order to prevent blood from flowing out of the heart and through the connector conduit prior to the insertion of the LVAD pump into the connector conduit.
Furthermore, since one-way valve 1275 is used to seal LVAD pump to the connector conduit, clamping mechanism 1060 (which is used with connector conduit 1005 to seal LVAD pump 1010 to outer sleeve 1035) can now be eliminated.
In order to provide the two seals, one-way valve 1275 may be constructed with one or more leaflets. Preferably, one-way valve 1275 may be formed from an implant grade silicone rubber.
In this embodiment, and as will be discussed in further detail below, LVAD pump 1010 is connected directly to sleeve conduit 1215, and screw clamp 1265 of sleeve conduit 1215 is tightened directly onto LVAD pump 1010 to lock sleeve conduit 1215 relative to LVAD pump 1010.
A preferred method for installing connector conduit 1205 into the left ventricle using applicator 1100 will now be described in detail below.
In the preferred method, an aortic anastomosis is first performed to connect an assembly comprising an outflow graft and LVAD pump 1010 to the ascending or descending aorta. For attachment to the ascending aorta, a median sternotomy is required, and, for attachment to the descending aorta, a left lateral thoracotomy is needed. The aortic anastomosis is typically achieved by side-clamping the aorta, performing an aortotomy, and suturing one end of the outflow graft to the slit aorta. The side clamp is partially removed to verify hemostasis, and then removed entirely. The outflow graft is typically cross-clamped throughout this process, and also for the insertion of connecter conduit 1005 into the left ventricle.
Looking now at
Connecter conduit 1205 is mounted onto applicator 1100 (
Pledgeted mattress sutures 1115 are then attached near the apex of the heart in a circular pattern around where a hole will be cored in the left ventricle. Sutures 1115 are loosely looped through sewing ring 1220 (
Using a scalpel, a stab wound is made at the point where the center of the hole will be located (
A shaft of applicator 1100 is inserted into the stab wound with balloon 1125 in its deflated state so as to position the deflated balloon inside of the left ventricle. Balloon 1125 is then inflated so as to provide a surface upon which coring knife 1110 can core a hole in the left ventricle.
Applicator 1100 is now used to core a hole 1120 in the left ventricle and simultaneously insert sleeve conduit 1215 into cored hole 1120 (
Once sutures 1115 are tied off, balloon 1125 is partially deflated. With one hand on sewing ring 1220, the surgeon withdraws applicator 1100 through connector conduit 1205. As the cylinder of the coring knife and the partially-deflated balloon 1125 pass through one-way valve 1275, one-way valve closes to maintain hemostasis.
LVAD pump 1010 is then aligned with connecter conduit 1205 and inserted into sleeve conduit 1215 (
Once LVAD pump 1010 is completely inserted within sleeve conduit 1205, clamp 1265 of sleeve conduit 1215, can be tightened and locked around LVAD pump 1010 so as to hold the assembly in place in its final configuration (
Installation of the connector conduit 1205 and LVAD pump 1010 is now complete. Significantly, hemostasis has been maintained at all times and the heart has remained beating during the installation procedure. Furthermore, one-way valve 1275 of the connector conduit 1205 eliminates the manual cross-clamping of tapered sleeve 1030 with cross clamp 1130 and the tightening of outer collar 1035 around LVAD pump 1010 which was required with connector conduit 1005.
If desired, one-way valve 1275 may be removed from connector conduit 1205 after insertion of LVAD pump 1010.
It will be understood that many additional changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art while remaining within the principles and scope of the present invention.
This patent application: (1) is a continuation-in-part of pending prior U.S. patent application Ser. No. 14/222,828, filed Mar. 24, 2014 by Correx, Inc. and Richard M. Beane et al. for APPARATUS AND METHOD FOR FORMING A HOLE IN A HOLLOW ORGAN (Attorney's Docket No. CORREX-033058-000014 CON 2), which in turn is a continuation of prior U.S. patent application Ser. No. 12/924,138, filed Sep. 21, 2010 by Richard M. Beane et al. for APPARATUS AND METHOD FOR FORMING A HOLE IN A HOLLOW ORGAN (Attorney's Docket No. CORREX-033058-000014 CON), which in turn is a continuation of prior U.S. patent application Ser. No. 11/581,081, filed Oct. 16, 2006 by Richard M. Beane et al. for APPARATUS AND METHOD FOR FORMING A HOLE IN A HOLLOW ORGAN (Attorney's Docket No. CORREX-033058-000014), which in turn (a) is a continuation-in-part of prior U.S. patent application Ser. No. 11/086,577, filed Mar. 23, 2005, by Richard M. Beane et al. for APPARATUS AND METHOD FOR CONNECTING A CONDUIT TO A HOLLOW ORGAN (Attorney's Docket No. CORREX-033058-000005), which claims priority to prior U.S. Provisional Application Ser. Nos. 60/555,308, filed Mar. 23, 2004; 60/635,652 filed Dec. 14, 2004; and 60/636,449 filed Dec. 15, 2004; and (b) claims priority to U.S. Provisional Application Ser. No. 60/726,222, filed Oct. 14, 2005; (2) claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 62/029,080, filed Jul. 25, 2014 by Correx, Inc. and Hardeep Singh et al. for METHOD AND APPARATUS FOR CONNECTING AN LVAD TO A HOLLOW ORGAN (Attorney's Docket No. CORREX-53B PROV); and (3) claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 61/928,828, filed Jan. 17, 2014 by Correx, Inc. and James Alan Crunkleton et al. for METHOD AND APPARATUS FOR CONNECTING AN LVAD TO A HOLLOW ORGAN (Attorney's Docket No. CORREX-54A PROV. The ten (10) above-identified patent applications are hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60555308 | Mar 2004 | US | |
| 60635652 | Dec 2004 | US | |
| 60636449 | Dec 2004 | US | |
| 60726222 | Oct 2005 | US | |
| 62029080 | Jul 2014 | US | |
| 61928828 | Jan 2014 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12924138 | Sep 2010 | US |
| Child | 14222828 | US | |
| Parent | 11581081 | Oct 2006 | US |
| Child | 12924138 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14222828 | Mar 2014 | US |
| Child | 14601028 | US | |
| Parent | 11086577 | Mar 2005 | US |
| Child | 11581081 | US |
