ADJUSTABLE CANNULATION ASSEMBLY AND METHODS THEREOF

A cannulation coupler has a primary branch comprising a retaining feature. The cannulation coupler also has a side inflow branch in communication with the primary branch. The cannulation coupler further has an outflow branch in communication with the primary branch and in communication with the side inflow branch. An adjustable cannulation assembly is also disclosed, having a cannulation coupler, an outer cannula, and an inner cannula. The cannulation coupler has 1) a primary branch comprising a retaining feature, 2) a side inflow branch in communication with the primary branch, and 3) an outflow branch in communication with the primary branch and in communication with the side inflow branch. The outer cannula is coupled to the primary branch. The inner cannula is coupled to the side inflow branch, wherein: 1) the inner cannula also passes through the primary branch; and 2) the inner cannula is coaxially slidable within the outer cannula.

FIELD

The claimed invention relates to cannulation assembly for minimally invasive cardiac interventions, and more specifically to an adjustable cannulation assembly for minimally invasive cardiac interventions.

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is utilized as a temporary form of mechanical circulatory support and simultaneous gas exchange for patients with cardiogenic shock or refractory heart failure, for example. In addition to providing a patient with circulatory support, ECMO may allow time for other treatments, promote recovery, or act as a bridge to alternate, more durable mechanical solutions to address acute or chronic cardiopulmonary failure. Typical ECMO circuits include a venous or return or outflow cannula, a pump, an oxygenator, and an arterial or inflow cannula.

A number of approaches can be utilized with an ECMO system, including via the apex of the heart for left-sided support (VA-ECMO) and via the right or left internal jugular vein for right-sided and/or respiratory support (VV-ECMO). Various forms of peripheral ECMO may involve femoro-femoral access, internal jugular access, or internal jugular vein access with return to a graft placed on the subclavian artery. These forms of ECMO, while effective, may present issues with mobility, issues with access site infection, in particular with the femoro-femoral access, as well as issues with rendering the patient non-ambulatory during the ECMO intervention and related procedures. These issues may adversely impact the healing process.

Transapical cannula placement into the left ventricle (VA-ECMO) can be used for patients requiring ECMO. Transapical cannula placement into the left ventricle in the setting of VA-ECMO for refractory heart failure normally requires sternotomy or thoracotomy in a highly vulnerable patient, which carries a significant risk of bleeding. VV-ECMO with access via the right or left internal jugular vein is also used, however, these approaches do not come without significant morbidity/mortality and advances must be made to maximize clinical benefits and minimize risk. Minimally invasive approaches are under development but are typically fixed in size and designed with healthy patients in mind or for patients with more predictable anatomical features in regard to the location, size, and shape of the heart. Therefore, there is a need for cannulation systems applicable to transapical and/or internal jugular vein cannula placement for use with ECMO that are adjustable based on patient size and anatomical variations. Such a customizable, patient-centered system would further enable cannula placement while allowing patients to ambulate on ECMO and therefore improve morale, hasten recovery, reduce morbidity, and optimize patient outcomes.

It will be appreciated that for purposes of clarity and where deemed appropriate, reference numerals have been repeated in the figures to indicate corresponding features, and that the various elements in the drawings have not necessarily been drawn to scale in order to better show the features.

DETAILED DESCRIPTION

FIG. 1is a top-left-front perspective view of a cannulation coupler suitable for use in a single cannula dual lumen adjustable cannulation assembly for minimally invasive ambulatory VA-ECMO. The cannulation coupler10has a primary branch12with a primary opening20in communication with a side inflow branch14and an outflow branch16. The primary branch12has a primary compression cap18configured to hold and secure a dual lumen cannula in the cannulation coupler10during use. The cannulation coupler10also has an inflow compression cap22on the inflow branch14, which is configured to hold and secure an inflow or inner cannula. The cannulation coupler10may be fabricated from a number of materials suitable for surgical use including surgical steel, plastic, or other suitable materials known in the art for transferring blood or similar fluids without interacting with the fluids unfavorably. It should be noted that the diameter of the inflow branch14is smaller than the primary branch12. Other embodiments of cannulation couplers may have a larger inflow branch than the primary branch. Still other embodiments of cannulation couplers may have inflow and primary branches having substantially similar diameters.

In an effort to clarify terminology, various descriptions have been used to characterize or describe the flow or direction of blood from the perspective of the cannulation coupler. The inflow cannula and the inflow branch of the cannulation coupler carries arterial or oxygenated blood from the ECMO system. The outflow cannula and the outflow branch, also referred to as a drainage cannula or drainage branch, of the cannulation coupler carries venous or deoxygenated blood back to the ECMO system for the purpose of oxygenating the blood flow. A primary branch merges an inflow and outflow branch or cannula into a dual lumen coaxial configuration. Other conventions in terminology, particular in reference to reversing the order of terminology relating to flow direction may exist within the medical community, but for the purposes of this description, the terminology will be used as noted above.

FIGS. 2A, 2B, 2C, 2D, 2E, and 2Fare front, left side, right side, rear, top, and bottom elevational views, respectively, of the cannulation coupler ofFIG. 1.FIGS. 2E and 2F, in particular, illustrate the respective locations and orientations of the inflow opening26and the outflow opening28with the inflow compression cap22assembled and attached.

FIG. 3is an exploded view illustrating assembly of the of the cannula coupler ofFIG. 1. The body10B of the cannulation coupler10defines helical threads36on an outside circumference of the primary branch12, near the primary opening20. A washer32having a step34to provide a depth limiter is inserted into the primary opening20of the primary branch12. The primary compression cap18has helical inner threads30that correspond to the threads36on the body10B of the cannulation coupler10and flats50on the outer circumference of the primary compression cap18. The flats50provide a configuration for tightening of the primary compression cap18by mechanical tools, although the primary compression cap18may also be tightened by hand. The primary compression cap18is not fully tightened until a cannula or lumen is also inserted into the primary opening20once the washer32and primary compression cap18are attached to the primary branch12. Once fully tightened, the primary compression cap18and primary washer32provide a leakproof and hermetically sealed connection for holding an outer dual lumen cannula providing a flow pathway through the connected outer cannula. On the end of the outflow branch16, the outflow branch16defines several barbs24. These barbs24are configured to temporarily yet reliably hold an outflow tube or lumen used in an ECMO surgical assembly and apparatus. On the inflow branch14of the body10B of the cannulation coupler10are a set of helical threads38. The inner diameter of the inflow branch14is configured such that a sealing element such as an o-ring40can be inserted into the inflow branch14without the o-ring40falling into the opening of the inflow branch14. This may be a step or a ledge on the inner diameter of the inflow branch14. This feature is not shown here, but should be known to those skilled in the art. Once the o-ring40is in place inside the inflow opening26of the inflow branch14, an inflow washer42is also placed in the inflow branch14. The inflow washer42has a step44to limit the depth of its insertion into the inflow opening26of the inflow branch14. The inflow compression cap22also defines inner threads46on an inner circumference and several flats48.

The flats48on the inflow compression cap22provide a configuration for tightening of the inflow compression cap22by mechanical tools, although the inflow compression cap22may also be tightened by hand. The inflow compression cap22is not fully tightened until a cannula or lumen is also inserted into the inflow opening26once the o-ring40, washer42and the inflow compression cap22are attached to the inflow branch14. Once fully tightened, the inflow compression cap22, o-ring40, and washer42provide a leakproof and hermetically sealed connection for holding an inner cannula providing a flow pathway into the cannulation coupler10.

FIG. 4is a cross-sectional view of a cannulation assembly utilizing the cannula coupler ofFIG. 1. An outer lumen or outer cannula52is shown inserted into the primary opening20and primary branch12end of the cannulation coupler10with the washer32in place and the primary compression cap18tightened and sealed. An inner lumen or inner cannula54is also shown inserted into the inflow opening26of the cannulation coupler10with the o-ring40in place and the inflow compression cap22tightened and sealed. The inner cannula54is further inserted into the outer cannula52through the primary branch12resulting in a dual lumen configuration. This could also be characterized as a coaxial dual lumen configuration or a cannula-in-cannula or lumen-in-lumen configuration.FIG. 4also illustrates the inflow direction56of the cannulation assembly88, which demonstrates the pathway and flow direction of the arterial blood into the aorta carried by the inner cannula54. Also illustrated is the pathway and outflow direction58of the venous or return flow carried by the outer cannula52in an ECMO system. These pathways and their overall system configuration will be discussed further in regard toFIG. 5.

FIG. 5is a partial cross-sectional view of a heart with a cannulation assembly inserted into a heart. A patient's heart60is shown with the distal end88D of the cannulation assembly88shown in its intended placement within the heart60. The distal end88D of the cannulation assembly88is inserted into an apical opening62in the left ventricle64of the heart60. The cannulation assembly88is secured to the heart60with several sutures66and supporting pledgets68surrounding the apical opening62. As inserted, the coaxial dual lumen cannula is configured such that the distal end52D of the outer cannula52is located in the left ventricle64. This allows the deoxygenated blood to flow in outflow direction58into the distal end52D of the outer cannula52back to the ECMO system for oxygenation. The distal end52D of the outer cannula52also defines several perforations70that further enable adequate blood flow should the distal end of the outer cannula52be pressed against the inner wall of the heart. The distal end54D of the inner cannula54is inserted further into the heart60, such that the distal end54D passes through an aortic valve76to deliver oxygenated blood from the inner cannula54into an aorta74. When inserted into the aorta74the inner cannula54is sealed relative to the left ventricle64by coaptation of aortic valve leaflets78of the aortic valve76. This effectively isolates the inflow of oxygenated blood from the inner cannula54into the aorta74from the outflow of deoxygenated blood from the apical opening62out from the left ventricle64. The inner cannula54further defines several perforations72at the distal end54D that further enable adequate blood flow should the distal end of the inner cannula54be otherwise obstructed. Since the coaxial dual lumen set up is further configured such that the inner cannula54can be slidable coaxially from a proximal direction to a distal direction, and vice versa within the outer cannula52, the relative position of the distal end54D of the inner cannula54can be adjustable in relation to the position of the52D distal end of the outer cannula52. This enables an adjustability not available to conventional cannulation assemblies that have fixed positions and are not coaxially oriented relative to an inner and outer lumen single cannula. This adjustability is important to accommodate variance in anatomical sizing and features that may be present across different patients. It should also be noted that while being carried in a single, dual lumen coaxial cannula, the inflow and the outflow pathways do not blend or cross contaminate. While a transapical approach is shown, other introductory methods including VA-ECMO, VV-ECMO, and others may be utilized with such an adjustable cannula assembly as described herein.

FIG. 6is a schematic view of a surgical setting employing the cannula coupler assembly ofFIG. 5.FIG. 6illustrates the relative positioning of a patient86and the cannulation assembly88as inserted. An inflow lumen84connected to the inner cannula54is connected to the inflow branch14of the cannulation coupler10and carries oxygenated blood from the ECMO apparatus80to the patient86. The outer portion of the outer cannula52brings deoxygenated blood out of the patient and into the ECMO apparatus80for oxygenation via an outflow lumen82. The cannulation coupler10may be secured to the patient86externally in order to facilitate ambulatory movement of the patient86while undergoing treatment.

FIG. 7is a top-left-front perspective view of another embodiment of a cannulation coupler suitable for use in a single cannula dual lumen adjustable cannulation assembly for minimally invasive ambulatory ECMO. The coaxial coupler or cannulation coupler90has a base port section or primary branch92with a base port opening104in communication with an inflow side port94and an external connection end or outflow branch114. The primary branch92has a base port cap100configured to hold and secure a dual lumen cannula in the cannulation coupler90during use. The base port cap100has a head102which is configured to assist the user in fastening the base port cap100onto the threaded end of the primary branch92with the use of an adjustable wrench or similar tool. While the head102illustrated is a hex-type nut shape, other fastening head shapes or configurations known to those skilled in the art may also be utilized. The cannulation coupler90also has side cap108on the inflow side port94, which is configured to hold and secure an inflow or inner cannula to the inflow side port94. The side cap108has a head110which is configured to assist the user in fastening the side cap108onto the threaded end of the inflow side port94with the use of an adjustable wrench or similar tool. While the head110illustrated is a hex-type nut shape, other fastening head shapes or configurations known to those skilled in the art may also be utilized. The outflow branch114has several concentric barbs112defined by the outflow branch114. These barbs112are configured to secure a tube or other cannula which may be placed onto the outflow branch114of the cannulation coupler90. As this embodiment illustrates barbs112on the outflow branch114, other securing means known in the art may be used in the assembly. The cannulation coupler90may be fabricated from a number of materials suitable for surgical use including surgical steel, plastic, or other suitable materials known in the art for transferring blood or similar fluids without interacting with the fluids unfavorably. It should be noted that the diameter of the inflow side port94is smaller than the primary branch92. Other embodiments of cannulation couplers may have a larger inflow side port than the primary branch. Still other embodiments of cannulation couplers may have inflow side port and primary branches having substantially similar diameters or sizes. A protrusion96defined by the primary branch92further defines a retaining feature, an attachment eyelet98configured to secure the cannulation coupler90to a patient once the cannulation coupler90and its accompanying assembly is installed and completed. A second inflow side port retaining feature or attachment eyelet106is also defined by the inflow side port94.FIGS. 8A, 8B, 8C, 8D, 8E, and 8Fare front, left side, right side, rear, top, and bottom elevational views, respectively, of the cannulation coupler ofFIG. 7.

FIGS. 9A-9Care a series of exploded views showing assembly steps of an adjustable cannulation assembly including the cannulation coupler ofFIG. 7. These assembly steps are shown outside the context of patient or instrumentation use for purposes of clarity. As shown inFIG. 9A, a first lumen132has been modified by cutting or otherwise removing a portion of a distal end132D proximal end132P of the first lumen132until approximately 2 mm from the reinforcement end is remaining on the distal end132D proximal end132P of the first lumen132. While not shown in this view, a portion of a distal end132D of the first lumen132may also be removed in order to facilitate subsequent steps of the assembly. This sectioning of a portion of the distal end132D of the first lumen132can be accomplished by beginning to section at or near a port hole in a distal end132D of a first lumen132, then cutting towards the distal end along a center line of the lumen. The distal end132D can be further flared and any excess material or sharp edges removed. Next, the bushing116is placed over the distal end132D of the first lumen132and moved towards the distal end132D proximal end132P of the first lumen132in direction134. The base port cap100is then placed over the distal end132D of the first lumen132and moved towards the distal end132D proximal end132P of the first lumen132in direction134. The distal end132D proximal end132P of the first lumen132and the insert118on the bushing116are then placed into the base port opening104of the cannulation coupler90such that the flange120of the bushing116is contacting the primary branch attachment cylinder122and the distal end132D proximal end132P of the first lumen132is fully seated and sealed in the base port opening104of the cannulation coupler90. The base port cap100is then tightened by hand or with an additional tool to fully fasten the base port cap100onto the cannulation coupler90and seal the first lumen132into the cannulation coupler90. The result of the preceding assembly steps is shown inFIG. 9B. Next, an o-ring130is inserted and seated into a proximal end94P of inflow side port94of the cannulation coupler90. Side cap108is placed over a distal end138D of a second lumen138and slid towards a proximal end138P of the second lumen138. The distal end138D of the second lumen138is then inserted into the proximal end94P of the inflow side port94, through the primary branch92and into the distal end132D proximal end132P of the first lumen132towards the distal end132D of the first lumen132in direction136. Now the portion of the first lumen132protruding from the base port cap100of the cannulation coupler90has the second lumen138coaxially inserted throughout its length and the distal end138D of the second lumen138is protruding from the distal end132D of the first lumen132, as illustrated inFIG. 9C.FIG. 9Cshows the result of the preceding assembly steps. A last assembly step shows the attachment of an external lumen140by placing a distal end140D of the external lumen140in direction142over the outflow branch114. While this method and order of component assembly has been described in regard toFIGS. 9A-9C, other means and orders of operation may be used in order to achieve the same structure and function of an adjustable cannulation assembly. The removing of a section from a proximal end of a first cannula, removing of a section from a distal tip of the first cannula, affixing the proximal end of the first cannula onto a main port of a cannulation coupler, inserting a distal end of a second cannula into a side port of the cannulation coupler, inserting the distal end of the second cannula into the proximal end of the first cannula such that the distal end of the second cannula protrudes from the distal end of the first cannula; and securing the second cannula into the cannulation coupler may be accomplished in alternate order of operation and fashion according to surgical team preference and/or availability of individual components.

An alternate means of assembly of the coaxial coupler assembly may be to first engage the drainage cannula via the base port. The o-ring is pushed within the delivery cannula side port and the delivery cannula is then inserted via the side port of the cannulation coupling device and through the delivery cannula. When the desired position of the cannula is confirmed externally, the bushing is pushed into place and threaded on the main body of the coupling device to ensure a hemostatic seal. Finally, the appropriate tubing, indicated for use with the chosen ECMO pump, is engaged with the remaining side port of the device.

When all the appropriate components are present and the system is completely assembled, the patient will be cannulated for ECMO via the surgeon's preferred approach based on the given patient's indication for mechanical circulatory support (MCS). This is done using standard sterile technique. This system allows for the possibility of cannulating through the apex of the heart for left-sided cardiac support (VA-ECMO) or via the internal jugular vein for right-sided cardiac and/or ventilatory support (VV-ECMO). This system allows for independent repositioning of the drainage and delivery cannulae relative to one another. Once the proper location of the cannulae is verified, mechanical circulatory support is initiated. Deoxygenated blood will be transported via a 34-Fr drainage cannula, through the cannulation coupler and assembly, and to the chosen ECMO pump for oxygenation. At this point oxygenated blood will be pumped to the delivery cannula, contained within the drainage cannula, and will transport blood to the chosen great artery.

FIG. 10is an exploded view illustrating assembly of the of the cannula coupler ofFIG. 7. The cannulation coupler90defines a primary branch92, having a primary opening104. A bushing116having a flange120and an insert118to provide a depth limiter is inserted into the primary opening104of the primary branch92. The base port cap100has inner threads, not shown in this view, that correspond to threads near the base port opening104of the cannulation coupler90and a head102having flat edges on the outer circumference of the base port cap100. The flats on the head102provide a configuration for tightening of the base port cap100by mechanical tools, although the base port cap100may also be tightened by hand. The base port cap100is not fully tightened until a cannula or lumen is also inserted into the base port opening104once the bushing116and base port cap100are attached to the primary branch92, as described in regard toFIGS. 9A-9C. Once fully tightened, the base port cap100and bushing116contribute to providing a leakproof and hermetically sealed connection for holding an outer dual lumen cannula providing a flow pathway through the connected outer first cannula. On an opposite end of the primary branch92, the cannulation coupler90also defines an outflow branch114having several barbs112. These barbs112are configured to temporarily yet reliably hold an outflow tube or lumen used in a VA-ECMO surgical assembly. On the side port94of the body of the cannulation coupler90are a set of inner threads, not shown in this view. The inner diameter of the inflow side port94is configured such that an o-ring130can be inserted into the side port94without the o-ring130falling into the opening of the inflow side port94. There is a step or a ledge on the inner diameter of the side port94. This feature is not shown here, but should be known to those skilled in the art. Once the o-ring130is in place inside the inflow opening of the side port94, a side cap108having a head110and further defining a flange128and a side cap insert126is also placed in the side port94. The flange128on the side cap108limits the depth of the insertion of the side cap108into the inflow opening of the side port94. The side cap108also defines inner threads, which are not shown in this view, and several flats on the head110, which are configured in a similar manner to that of the base port cap100.

FIG. 11is a schematic view of a surgical setting employing the cannula coupler assembly illustrated inFIGS. 9A-9C.FIG. 11is a cross-sectional view of a cannulation assembly144utilizing the cannula coupler ofFIG. 7. An outer first lumen132is shown inserted into the base port cap100and primary branch92end of the cannulation coupler90with the bushing116in place and the base port cap100tightened and sealed. An inner second lumen138is also shown inserted into the side port94of the cannulation coupler90with the o-ring130in place and the side cap108tightened and sealed. The inner second lumen138is further inserted into the outer first lumen132through the side port94and through the primary branch92and base port cap100in a dual lumen configuration. This could also be characterized as a coaxial dual lumen configuration or a cannula-in-cannula or lumen-in-lumen configuration.FIG. 11also illustrates the inflow direction143of the cannulation assembly144, which demonstrates the pathway and flow direction of the arterial blood into the aorta carried by the inner second lumen138. Also illustrated is the pathway and outflow direction145of the venous or return flow carried by the outer first lumen132in an ECMO system.

The dual lumen coaxial cannulation assembly described herein results in an adjustable cannula intended towards ambulatory ECMO with a novel coupler. The cannulation system is intended for use in a minimally invasive transapical closure system, but may be applicable elsewhere. In many ECMO related procedures, the inflow or outflow pressures may or may not be monitored during the procedures. In some cases, only the flow rate of the inflow portion of the circuit is monitored during an ECMO procedure. A flow rate of 5 liters per minute is usually adequate for VA-ECMO. A target of 4.8-5.5 liters per minute is a common target and may be modified outside the stated boundaries relative to the treatment needs of a given patient, but 5 liters per minute is an adequate target value. V-V ECMO as introduced via an inner jugular vein may require flows as high as 6-7 liters per minute utilizing two separate 25 French cannulas. Pressure and flow are commonly the measurable criteria in perfusion technology related procedures.

In experimentation conducted using clinical ECMO oxygenation and pumping apparatus, control for flow was established using separate cannulas of the similar ranges of sizes as experimentally used. Near equivalent flow rates and pressures were observed when comparing a common ECMO setup using a 17 French inflow cannula and a 24 French outflow cannula with the coaxial dual lumen cannula assembly as described herein. The dimensions of the coaxial dual lumen were 17 French inflow or inner cannula inserted into a 34 French outer cannula. This phenomenon can be explained by the relationship between the cross-sectional diameters of the inner and outer cannula in the slidable coaxial dual lumen cannula assembly. The inflow cannula of the separate (non-coaxial) and coaxial cannula assemblies were both 17 French, or the same size. The outflow cannula of the non-coaxial cannula assembly was 24 French, while the outflow cannula of the coaxial cannula assembly was 34 French. The 34 French with the 17 French inner cannula inserted in the coaxial assembly results in restricted internal cross-sectional area and is comparable to a similar cross-sectional area in the 24 French outflow cannula in the non-coaxial cannula assembly. While these specific numbers are provided by way of illustrating the concept, they are not meant to be limited to only these dimensions of inflow and outflow cannulas, since the requirements of the system and patient condition may warrant the use or configuration of dual lumen coaxial cannula assemblies outside of the dimensions stated here by way of example.

FIG. 12is a perspective view of another embodiment of a cannulation coupler suitable for use in a single cannula dual lumen adjustable cannulation assembly for minimally invasive ambulatory ECMO. The cannulation coupler146has a primary branch148with a base port156in communication with a side inflow branch150and a drainage or external port, or outflow branch158, each defined by the structure of the cannulation coupler146. The primary branch148defines the base port156at one end which defines several concentric barbs160configured to securely yet releasably hold a lumen or cannula in place. The primary branch148also defines the outflow branch158at an opposite end which also defines several concentric barbs162also configured to securely yet releasably hold a lumen or cannula in place. The primary branch148also defines a base port limit164and an external port limit166at either end, configured to provide a sealing surface and consistent limitation for a lumen or cannula connected to either the base port156or the outflow branch158. The primary branch148of the cannulation coupler146also defines several retaining features152,154which are configured to anchor and secure the cannulation coupler146to a patient or to other apparatus used in an ambulatory ECMO procedure and treatment. The retaining features and the act of securing the cannulation coupler146and associated assembly to a patient enables and allows mobility of a patient while undergoing treatment under such procedures. One retaining feature154is adjacent to an outer junction between the side inflow branch150and the primary branch148. On the side inflow branch150, the cannulation coupler146also has a side inflow branch cap168which defines a head170, the features of which have been previously described herein. The side inflow branch150further comprises helical threading, not shown in this view, on a portion of an inner circumference. As previously described herein, the side inflow branch cap168has an aperture or opening configured to pass through and hermetically seal there within a lumen or cannula as a part of the overall assembly. The cap168also has helical threads on an outer circumference that interlock with the inner threads on the side inflow branch150. An axis defined by the side inflow branch150is disposed at an angle relative to an axis defined by the primary branch148. While the angle illustrated inFIG. 12is 25 degrees, alternate angles may be used in other embodiments. An axis defined by the outflow branch158is parallel to an axis defined by the primary branch. Alternate angles may be utilized in other embodiments of a cannulation coupler. The cannulation coupler146may be fabricated from a number of materials suitable for surgical use including surgical steel, plastic, or other suitable materials known in the art for transferring blood or similar fluids without interacting with the fluids unfavorably. It should be noted that the diameter of the side inflow branch150is smaller than the primary branch148. Other embodiments of cannulation couplers may have a larger side inflow branch than the primary branch. Still other embodiments of cannulation couplers may have side inflow branch and primary branches having substantially similar diameters.

FIG. 13is a top-left-front perspective view of an adjustable cannulation assembly. This embodiment of an adjustable cannulation assembly172includes a first IVC cannula174defining a first plurality of IVC perforations188, a second plurality of upper SVC perforations184, and a side port186in communication with an IVC cannula channel190. The IVC cannula channel190of the first IVC cannula174continues from a distal end174D of the first IVC cannula174to a proximal end174P of the first IVC cannula174. The side port186is configured such that it exits the IVC cannula channel190radially and is on a side of the first IVC cannula174. The first IVC cannula174is coupled to the cannulation coupler146at the base port156of the cannulation coupler146. On an opposite end of the cannulation coupler146, an eccentric obturator cap180is coupled to the outflow branch158of the cannulation coupler146. Inserted within the eccentric obturator cap180and continuing throughout the primary branch of the cannulation coupler146, and further through the IVC cannula channel190of the first IVC cannula174is a first IVC obturator178. The first IVC obturator178defines a knob194at a proximal end178P of the first IVC obturator178and an obturator channel192from a proximal end178P of the first IVC obturator178to a distal end178D of the first IVC obturator178. The distal end178D of the first IVC obturator178is visible protruding from the distal end174D of the first IVC cannula174. Inserted within the side inflow branch cap168of the side inflow branch150of the cannulation coupler146is a pulmonary artery guidewire introducer176. The pulmonary artery guidewire introducer176extends to the side port186of the first IVC cannula174, where it terminates in a guidewire introducer exit196defined by a distal end176D of the pulmonary artery guidewire introducer176. A proximal end176P of the pulmonary artery guidewire introducer176can be seen protruding from the side inflow branch cap168of the side inflow branch150on the cannulation coupler146. A pulmonary artery guidewire introducer plug182is fitted into the proximal end176P of the pulmonary artery guidewire introducer176. The pulmonary artery guidewire introducer176will be discussed in further detail later in regard toFIGS. 18A and 18B.

FIG. 14is an exploded perspective view of the adjustable cannulation assembly ofFIG. 13. The first IVC cannula174is coupled at the proximal end174P to the base port156of the cannulation coupler146, and held fixedly in place by the several barbs on the end of the base port156. The o-ring169is placed into the side inflow branch150of the cannulation coupler146, followed by the cap168, which is screwed into the side inflow branch150over the o-ring169. The eccentric obturator cap180, of which an eccentric opening198is now visible, is attached to the external port158of the cannulation coupler146, and held fixedly in place by the several barbs on the end of the external port158. Next, the first IVC obturator178is inserted through the eccentric opening198of the eccentric obturator cap180, and through the first IVC cannula174to the proximal end174P of the first IVC cannula174. It should be noted that the off center location of the eccentric opening198in the eccentric obturator cap180orients the first IVC obturator178towards one side of the first IVC cannula174. Next, the pulmonary artery guidewire introducer176, which further defines a body240portion, a neck200portion, and a fitting portion202is inserted by placing the distal end176D of the pulmonary artery guidewire introducer176into the cap168, through the side inflow branch150of the cannulation coupler146, and finally into the first IVC cannula174, terminating with the guidewire introducer exit196firmly positioned within the side port186of the first IVC cannula174. Finally, the pulmonary artery guidewire introducer plug182, which further defines an insert206portion, is releasably pressed into the entrance204of the pulmonary artery guidewire introducer176.

FIG. 15is a top-left-front perspective view of a pulmonary artery guidewire director for use accompanying the adjustable cannulation assembly ofFIG. 13. A pulmonary artery guidewire director208defines a knob210at a proximal end208P. The knob210further defines a directional indicator fin212, which is configured to enable turning or directionally orienting a pulmonary artery guidewire when the pulmonary artery guidewire director208is used within a minimally invasive procedure utilizing an adjustable cannulation assembly172as described herein. The pulmonary artery guidewire director208also defines a straight portion218and a curved portion216towards a distal end208D of the pulmonary artery guidewire director208. The pulmonary artery guidewire director208also has an inner channel214, from the proximal end208P to the distal end208D of the pulmonary artery guidewire director208configured to guide and direct a guidewire therethrough. The pulmonary artery guidewire director208is comprised of a pre-curved flexible plastic material suitable for surgical use which can be introduced throughout a cannulation assembly such as the one described herein yet regain its shape upon exit of any constraint within a lumen or other delivery channel. While illustrated here as a preformed curved embodiment, alternate embodiments may be straight or otherwise shaped depending upon surgical preference, anatomical variations or other conditions, or configurations of accompanying guidewire structures or designs. The proposed use of the pulmonary artery guidewire director208will be described in further detail in regard toFIGS. 19A-19H and 19J-19N.

FIG. 16is a top-left-front perspective view of an inner cannula for use accompanying the adjustable cannulation assembly ofFIG. 13. An inner cannula220having a proximal end220P and a distal end220D also defines an inner channel236passing therethrough from the proximal end220P to the distal end220D, and several distal perforations222at the distal end220D of the inner cannula220. Typical commercially available cannulae used with an adjustable cannulation assembly as described herein will be a singular straight lumen, but the inner cannula220is shown in its desired state within the adjustable cannulation assembly172and as related to the procedures described for use within the adjustable cannulation assembly172. The inner cannula220illustrated inFIG. 16is sized as a 19 Fr cannula, but the specific size, additional design features, and configuration of the inner cannula used in minimally invasive surgical procedures described herein may be dependent upon the immediate surgical considerations as well as anatomical variations of a patient or available accompanying surgical equipment. The proposed use of the inner cannula220will be described in further detail in regard toFIGS. 19A-19H and 19J-19N.

FIG. 17is a top-left-front perspective view of an inner cannula obturator for use accompanying the adjustable cannulation assembly ofFIG. 13. An inner cannula obturator226having a proximal end226P and a distal end226D defines an inner channel236passing therethrough from the proximal end226P to the distal end226D of the inner cannula obturator226. The inner channel236is configured to receive a guidewire such that the inner cannula obturator226may be utilized to help push and direct the inner cannula220through the adjustable cannulation assembly172. The inner cannula obturator226also defines a //228at the proximal end226P. Alternate embodiments may have additional handle features such as a directional indicator. The inner cannula obturator226is illustrated as made from a pre-curved flexible plastic material suitable for surgical use that can be introduced throughout a cannulation assembly such as the one described herein, yet regain its shape upon exit of any constraint within a lumen or other delivery channel. While illustrated here as a preformed curved embodiment, alternate embodiments may be straight or otherwise shaped depending upon surgical preference, anatomical variations or other conditions, or configurations of accompanying guidewire structures or designs. The proposed use of the inner cannula obturator226for advancing an inner cannula through an adjustable cannulation assembly will be described in further detail in regard toFIGS. 19A-19H and 19J-19N.

FIGS. 18A and 18Bare top-left-front and bottom-right-rear perspective views, respectively, of the pulmonary artery guidewire introducer of the adjustable cannulation assembly ofFIG. 13.FIG. 18Aillustrates the pulmonary artery guidewire introducer176, which defines a fitting portion202and a cap242at a distal end176D. The fitting portion202is sized and configured to fit within the cap of the cannulation coupler146in the adjustable cannulation assembly172ofFIG. 13. Adjacent to the proximal end176P is a neck200coupled to the fitting portion202and a body240coupled to the neck200. Along the body240of the pulmonary artery guidewire introducer176is a second side channel246which begins at an aperture244near the junction between the neck200and body240and terminates at a side port interlock feature248at a distal end176D of the pulmonary artery guidewire introducer176. The side port interlock feature248is sized and configured to interface in a complementary fashion with the side port186of the first IVC cannula174within the adjustable cannulation assembly172. This feature ensures that the pulmonary artery guidewire introducer176is correctly positioned within the first IVC cannula174and that a guidewire inserted into and through the pulmonary artery guidewire introducer176will be reliably directed outward from the side port interlock feature248portion of the pulmonary artery guidewire introducer176and out of the side port186of the adjustable cannulation assembly172.FIG. 18Bis a bottom-right-rear perspective view of the pulmonary artery guidewire introducer176and illustrates a first side channel250located within the neck200portion of the pulmonary artery guidewire introducer176. The pulmonary artery guidewire introducer176is configured to receive and direct a guidewire from the entrance204at the proximal end176P into the first side channel250, through the aperture244to the opposite side of the pulmonary artery guidewire introducer176, through the second side channel246as shown inFIG. 18A, and out of the side port interlock feature248at the distal end176D of the pulmonary artery guidewire introducer176. The pulmonary artery guidewire introducer176is made from a flexible, surgical grade plastic or other material and may also have an enclosing tube-like structure, collar, or other similar retention feature coupled around the neck200to further entrain and guide a guidewire inserted throughout the pulmonary artery guidewire introducer176as described. The intended use of the pulmonary artery guidewire introducer176within the adjustable cannulation assembly172will be described in further detail in regard toFIGS. 19A-19H and 19J-19N.

FIGS. 19A-19H and 19J-19Nare schematic illustrations of a surgical method for use of the adjustable cannulation assembly ofFIG. 13with the additional components ofFIG. 15,FIG. 16, andFIG. 17. It should be noted thatFIG. 19Iwas not used so as not to be confused with the number191. While previously described embodiments of adjustable cannulation assemblies, for example, as described in regard toFIGS. 1-10may have been utilized in a minimally invasive surgical procedure involving a transapical entry position, alternate minimally invasive approaches that still preserve patient mobility and ambulatory accommodation may be employed. For example, utilization of an adjustable cannulation assembly having five ports such as the embodiment illustrated inFIG. 13via access or entry via the right internal jugular vein (IJ) may be used based on the immediate needs of a particular patient, surgical team preference, accessory equipment availability, or combinations thereof. Preparation of a patient for use of an adjustable cannulation assembly via the right internal jugular vein (IJ) includes establishing a patient in a prone Trendelenburg position with legs elevated and head down. The skin centered over the right IJ is prepared, a standard skin incision and superficial dissection is performed, using direct pressure tamponade as needed, and ultrasound guidance is used to perform a needle puncture of the right IJ vein. Needle tip location may be confirmed using blood aspiration. While these steps are not explicitly illustrated herein, they should be well-known to one skilled in the art. As illustrated inFIG. 19A, once a patient is prepared for a right inner jugular access ECMO cannulation procedure, an IVC guidewire270is placed into the inner jugular entry254through a superior vena cava256portion of a patient's heart252, and down through to an inferior vena cava258, using ultrasound guidance, and optionally, the use of a snare from the groin if necessary. Other features of the heart are illustrated herein, including their approximate relative locations, including a right atrium260, right ventricle262, tricuspid valve263, pulmonary valve leaflets264, pulmonary valve266, and pulmonary artery268.

To proceed with inferior vena cava cannulation, the wound site external to the patient is then serially dilated to accommodate a 30-Fr outer diameter tube. The adjustable cannulation assembly172is prepared for use and flushed with saline. As illustrated inFIG. 19B, the IVC guidewire270is passed into the conical tip of the first IVC obturator178at the distal end172D of the adjustable cannulation assembly172. The adjustable cannulation assembly172is then advanced in direction274towards the inferior vena cava258until the lower IVC perforations188in the IVC cannula174are seen by ultrasound in the IVC. This intended position is shown inFIG. 19C. Right ventricle cannulation is then accomplished by first removing the pulmonary artery guidewire introducer plug182from the pulmonary artery guidewire introducer176located in the side inflow branch150of the cannulation coupler146. A pulmonary artery guidewire276is then introduced into the entrance204of the pulmonary artery guidewire introducer176in direction289, as illustrated inFIG. 19D.FIG. 19Eshows the intended location of a j-tip278at a distal end of the pulmonary artery guidewire276as directed by the first side channel and second side channel of the pulmonary artery guidewire introducer176, as previously described in regard toFIGS. 18A and 18B. The j-tip278of the pulmonary artery guidewire276exits through the side port186and into the right atrium260. Further details describing the pulmonary artery guidewire276pathway through the pulmonary artery guidewire introducer176and through the adjustable cannulation assembly172will be further described in regard toFIG. 20andFIGS. 21A-21F. At this point the rotational position should be established and confirmed, such that the side inflow branch150of the cannulation coupler146is directed away from the patient's chin and neck. The pulmonary artery guidewire276may be advanced and retracted to aim the j-tip278towards the tricuspid valve263. The j-tip278is then advanced through the tricuspid valve263and into the right ventricle262. Once the pulmonary artery guidewire276is in position in the right ventricle262as illustrated inFIG. 19E, the IVC obturator178and the IVC guidewire270are removed from the external port158of the cannulation coupler146by retracting in direction290, as illustrated inFIG. 19F. Next, as shown inFIG. 19G, an ECMO drainage tube292is attached to the external port158of the cannulation coupler146and secured as needed.FIG. 19Hillustrates the removal of the pulmonary artery guidewire introducer176via direction294and removing the pulmonary artery guidewire276from the internal channels of the pulmonary artery guidewire introducer176, leaving the j-tip278of the pulmonary artery guidewire276in the right ventricle262.

Cannulation of the pulmonary artery is then accomplished by advancing the flexible preformed pulmonary artery guidewire director208over the pulmonary artery guidewire276and into the side inflow branch150of the cannulation coupler146until the radiopaque distal end exits the side port186and enters the right ventricle262. Alternatively, a steerable or pre-angled guidewire may be used in place of the pulmonary artery guidewire director208. The pulmonary artery guidewire director208is manipulated, along with its indwelling pulmonary artery guidewire276, by use of the directional indicator fin212to pass the pulmonary artery guidewire276distal to the pulmonic valve262. Alternatively, if indicated, this pulmonary artery guidewire276may be replaced with a larger caliber, more rigid, or otherwise configured guidewire. The final placement of this pulmonary artery guidewire director208and location of the pulmonary artery guidewire276are illustrated inFIG. 19J. Once the j-tip278of the pulmonary artery guidewire276is in either the left or right branch of the pulmonary artery268the pulmonary artery guidewire director208is removed. The pulmonary artery guidewire director208is shown removed and the j-tip278of the pulmonary artery guidewire276is located in the pulmonary artery268inFIG. 19K. A flushed inner delivery cannula220with the in-place inner cannula obturator226over the pulmonary artery guidewire276is advanced through the side inflow branch150in the cannulation coupler146as shown inFIG. 19L, and through the adjustable cannulation assembly172until exiting the side port186as shown inFIG. 19M. While a 19-Fr inner cannula is shown in use, other sizes or configurations may be used as dictated by surgical preference or patient anatomy. The inner cannula220is advanced over the pulmonary artery guidewire276until all of the distal perforations222are distal to the coapted pulmonary valve leaflets in the pulmonary valve266. Achieving this may depend on elements described herein having varying dimensions, additional tools, or complimentary techniques not described herein, but known to those skilled in the art, and may depend on patient anatomy or other considerations. The inner cannula obturator226and the pulmonary artery guidewire276are then removed from the adjustable cannulation assembly172via the side inflow branch150of the cannulation coupler146as illustrated inFIG. 19N. Once in this configuration, an inflow ECMO tube is attached or coupled to the inner cannula220and secured as needed. The adjustable cannulation assembly172is now vented and air-free flow is established, the optimal locations of the lower IVC perforations188and upper SVC perforations184in the IVC cannula174are reconfirmed, and the cannulation coupler146is secured to the skin near the initial puncture site to establish relative location of the adjustable cannulation assembly172. Supra-valvular positioning of all distal perforations222in the inner delivery cannula220and appropriate flow rates and pressures are reconfirmed. The ECMO circuit has now been established. A wrench or other suitable tool is then used to tighten and lock the nut cap on the cannulation coupler146. Finally, the procedure concludes with confirmation of cannula position flows and pressures, taping exposed assembly connections to further cover and secure components outside of the patient's body, and dressing the wound site.

FIG. 20is a side view of the adjustable cannulation assembly ofFIG. 13illustrating several locations along a path followed by a directed pulmonary artery guidewire through the adjustable cannulation assembly.FIGS. 21A-21Fare a series of several cross-sectional views of the adjustable cannulation assembly indicated inFIG. 20. The cross-sections follow the path of the pulmonary artery guidewire from the side inflow branch150of the cannulation coupler146down through the IVC cannula174and out of the side port186of the IVC cannula174. While procedurally, the elements shown inFIGS. 21A-21Fmay not be inserted within the assembly at the same time, these cross-sections are intended to be descriptive of the path of the pulmonary artery guidewire276through the adjustable cannulation assembly172as directed primarily by the pulmonary artery guidewire introducer176. The cross-section illustrated inFIG. 21Ashows the respective locations of the IVC guidewire270within the IVC obturator178. The eccentric opening in the eccentric obturator cap180is located such that the first IVC obturator178is close to the wall of the external port158of the cannulation coupler146when inserted into the adjustable cannulation assembly172. Moving towards the cross-section illustrated inFIG. 21B, the neck200of the pulmonary artery guidewire introducer176and the placement of the pulmonary artery guidewire276positioned within is shown in its location relative to the first IVC obturator178within the base port156of the cannulation coupler146. The cross-section illustrated inFIG. 21Cshows the location of the IVC obturator178and the pulmonary artery guidewire introducer176within the IVC cannula174, along with the respective locations of the IVC guidewire270and pulmonary artery guidewire276. The complimentary shape of the body240portion of the pulmonary artery guidewire introducer176compared to the outer circumference of the IVC obturator178ensures proper orientation and direction of the pulmonary artery guidewire276through the adjustable cannulation assembly172. The neck200configuration, combined with the complimentary shape and contour of the body240portion of the pulmonary artery guidewire introducer176allow the pulmonary artery guidewire introducer176to be inserted into the adjustable cannulation assembly172in a manner that enables the pulmonary artery guidewire276to be inserted into the side inflow branch150of the cannulation coupler146and pass around the outer circumference of the IVC obturator178in order to exit from the side port186of the IVC cannula174of the adjustable cannulation assembly172. The cross-section illustrated inFIG. 21Dillustrates a position where the pulmonary artery guidewire276has been passed through the aperture244within the pulmonary artery guidewire introducer176, as previously described in regard toFIGS. 18A-18B, and has moved from the first side channel250in the neck200over through the aperture244to the second side channel246within the pulmonary artery guidewire introducer176. The cross-section illustrated inFIG. 21Eshows a position further down the adjustable cannulation assembly172where the side port interlock feature248of the pulmonary artery guidewire introducer176meets the side port186of the IVC cannula174, and the pulmonary artery guidewire276exits the side port interlock feature248and the side port186into the right atrium260as first described in regard toFIG. 19E. The cross-section illustrated inFIG. 21Fshows a position below the side port186on the IVC cannula174, where the IVC obturator178is no longer positionally constrained by either the pulmonary artery guidewire introducer176or the eccentric opening in the eccentric obturator cap180.

FIGS. 22A and 22Bare side views of the embodiment of an adjustable cannulation assembly discussed previously inFIG. 9A-9C, illustrating adjustment of the second lumen138relative to the first lumen132. One benefit of the system and approach described herein is that the relative position of the lumen138,132can be adjusted for each unique patient anatomy. In other words, the second lumen138does not need to stick out a fixed distance from the first lumen132. As shown inFIG. 22A, the second lumen138may be extended294relative to the first lumen132. Similarly, as shown inFIG. 22B, the second lumen138may be retracted relative to the first lumen132.

Various advantages of an adjustable cannulation assembly and methods thereof have been discussed above. Embodiments discussed herein have been described by way of example in this specification. It will be apparent to those skilled in the art that the foregoing detailed disclosure is intended to be presented by way of example only, and is not limiting. As just one example, although the end effectors in the discussed examples were often focused on the use of a scope, such systems could be used to position other types of surgical equipment. Various alterations, improvements, and modifications will occur and are intended to those skilled in the art, though not expressly stated herein. These alterations, improvements, and modifications are intended to be suggested hereby, and are within the spirit and the scope of the claimed invention. The drawings included herein are not necessarily drawn to scale. Additionally, the recited order of processing elements or sequences, or the use of numbers, letters, or other designations therefore, is not intended to limit the claims to any order, except as may be specified in the claims. Accordingly, the invention is limited only by the following claims and equivalents thereto.