Patent Application
20220160389
The invention relates to devices and methods for performing endovascular access to the cardiovascular system or other body vessels or body lumens, especially procedures performed in the fields of cardiology, radiology, electrophysiology, and surgery.
The currently accepted procedure for left atrial access involves routing a needle called a Brockenbrough needle into the right atrium with the Brockenbrough needle pre-placed within a guiding catheter. The guiding catheter specifically preferred for use with a Brockenbrough needle is called a Mullins-type catheter or transseptal introducer. The Brockenbrough needle is a long, small diameter punch, generally formed from a stainless steel wire stylet that is surrounded by a stainless steel tube. Other devices, designed for the same purpose, employ radiofrequency ablation to perforate the atrial wall but these devices expose the myocardium to burning, potentially reduced healing characteristics, and increased risk of subsequent scarring.
The methods and devices disclosed below provide for easier penetration of a dilator of an endoluminal punch system through the wall of a body lumen, such as the fossa ovalis. The endoluminal punch of the system is fitted with a radially extending cutting blade configured to cut a portion of a perforation in the tissue initially created by the penetrating tip of the punch, to make it easier for the larger dilator tip surrounding the punch to pass through the perforation. The dilator has, in addition to the lumen which accommodates the main portion of the punch (typically a round lumen to accommodate a tubular or cylindrical punch with a round transverse cross section), the dilator has a channel, open to the lumen and extending the length of the dilator lumen, sized to accommodate the cutting blade extending radially from the punch. In use, as the punch is advanced out the distal end of the dilator to penetrate the fossa ovalis, the cutting blade with extend radially from a tapered distal tip of the dilator to engage the fossa ovalis and cut a small slit in the fossa ovalis at the edge of the perforation, facilitating passage of the dilator through the perforation.
In accordance with current terminology pertaining to medical devices, the proximal direction will be that direction on the device that is furthest from the patient and closest to the user, while the distal direction is that direction closest to the patient and furthest from the user. These directions are applied along the longitudinal axis of the device, which is generally an axially elongate structure having one or more lumens or channels extending through the proximal end to the distal end and running substantially the entire length of the device.
In an embodiment, the invention is an endoluminally, transvascularly, or endovascularly placed tissue punch, with internal deflectability or the ability to articulate, at its distal end, in a direction away from its longitudinal axis. The punch can also be termed a catheter, needle, or cannula. The punch is generally fabricated from stainless steel and comprises an outer tube, an intermediate tube, a central stylet wire, and a distal articulating region. The deflecting or articulating mechanism is integral to the punch. The punch, needle, or catheter is sufficiently rigid, in an embodiment, that it can be used as an internal guidewire or internal guide catheter. The punch is useful for animals, including mammals and human patients and is routed through body lumens or other body structures to reach its target destination.
In an embodiment, the punch comprises a core wire or stylet, an inner tube and an outer tube. The inner tube can comprise a sharpened distal end to facilitate tissue puncture. The sharpened end can comprise bevels, facets, sharpened blade-like structures, or the like. The core wire or stylet can be blunted at the distal end to prevent damage to structures such as tissue, the sheath, or the dilator during advancement of the endoluminal punch, caused by the sharpened distal end of the endoluminal punch. In an embodiment, the stylet can be removable or non-removable. In some embodiments, the stylet can have a large diameter to minimize trauma and shield sharp structures on the distal tip of the endoluminal punch. The endoluminal punch further comprises a hub at its proximal end which permits grasping of the punch and can also include a stopcock or valve to serve as a lock for the stylet, as well as a valve for control of fluid passage into and out from the innermost lumen within which the stylet or inner core wire resides. The hub can further comprise additional ports to facilitate the administration or withdrawal of fluids or pressure measurement. The additional ports can be terminated with Luer lock connectors or with flexible lead lines terminated with Luer lock connectors, stopcocks, or the like. The proximal end further can comprise one or more control mechanisms to manipulate the amount of articulation at the distal end of the catheter. The proximal end further is terminated with a female Luer or Luer lock port, which is suitable for attachment of pressure monitoring lines, dye injection lines, vacuum lines, a combination thereof, or the like. Other structures can be provided to alter the distal tip of the endoluminal punch such as changing it from blunter and less traumatic to sharper and more capable of tissue penetration. Such distal tip altering structures can include a piercing stylet which has an extremely sharp distal end or which transmits energy to the distal tip of the endoluminal punch. The energy can be in the form of simple manually applied force, mechanical vibration, mechanical rotation, ultrasound, high intensity focused ultrasound, electrical power to heat the distal tip, cryogenic energy, laser energy, and the like. The distal tip altering structure can comprise a quick release or controlled retraction mechanism which can be dumb or it can be responsive to measurements of force, tissue properties, or the like.
Other embodiments of the inventions comprise methods of use. Keeping the method of use as close to current techniques is preferable since it reduces the learning curve and physician confidence in the procedure. The general procedure comprises placing a guidewire beyond the right atrium via a percutaneous access point in the right femoral vein or jugular vein. A transseptal introducer is advanced over the guidewire, the transseptal introducer comprising a sheath and a dilator. The dilator further comprises a shaft, a tapered distal tip, a central through lumen, and a hub affixed to the proximal end of the shaft. The sheath comprises a hemostasis valve to seal to the dilator shaft, a side port with stopcock communicating with the central lumen of the sheath, and the like. The sheath and the dilator can comprise a pre-formed curve near the distal end. The guidewire is next removed and a transseptal needle or other crossing system is advanced through the central lumen of the dilator. The transseptal needle with the transseptal introducer riding on its back can be targeted at a specific site on the interatrial wall, generally in the area of the fossa Ovalis. The tissue is tented by the dilator to stretch the tissue at the target site and exert a crossing force on the tissue. The transseptal needle is preferably retracted within the blunt distal tip of the dilator to prevent any chance of unwanted or inadvertent tissue perforation. Once the target is secured, the transseptal needle is advanced distal to the distal tip of the dilator thus exposing it to the tissue and causing cutting of the tented tissue. The transseptal needle and dilator/sheath are advanced across the tissue to gain access to the other side. The transseptal needle and dilator can be removed at this time to provide a pathway through the sheath or a guidewire can be reinserted to provide a track for subsequent catheterizations.
In another embodiment, the core wire, stylet is sharpened and serves as a tissue punch. In this embodiment, the distal end of the hollow tubes of the punch are blunted and made relatively atraumatic. Once the core wire punch has completed tissue penetration, the outer tubes are advanced over the central punch wire through the penetration and into the left atrium. In another embodiment, a pressure monitoring device such as a catheter tip pressure transducer, or a pressure line terminated by a pressure transducer, can be affixed to a quick connect, generally a Luer fitting, at the proximal end of the punch hub. By monitoring pressure, it is possible to determine when the distal end of the punch has passed from, for example, the right atrium into the left atrium, because the pressure versus time curves in these two chambers are measurably, or visually, different. The proximal end of the hub further has provision for attachment to a dye injection line for use in injecting radiographic contrast media through the central lumen of the punch. Typically, a manifold can be attached to the Luer fitting on the proximal end of the hub, the manifold allowing for pressure monitoring, for example on a straight through port, and for radiopaque dye injection, for example through a side port. A stopcock, or other valve, can be used to control which port is operably connected to the central lumen of the punch.
In some embodiments, the inner tube, the outer tube, or both can have slots imparted into their walls to impart controlled degrees of flexibility. The slots can be configured as “snake cuts” to form a series of ribs with one or more spines. The spines can be oriented at a given circumferential position on the outer tube, the inner tube, or both. The spines can also have non-constant orientations. In some embodiments, only the outer tube is slotted. The slots can be generated within the distal portion of the outer tube where the curve is generated. This bendable distance can range between about 0.5-cm and 20-cm of the end and preferably between about 1-cm and 12-cm of the distal end. The slot widths can range between 0.001 inches and 0.010 inches with a preferable width of about 0.001 to 0.005 inches. In exemplary embodiments, the slot widths are about 0.003 inches. In some embodiments, it is desirable to have the outer tube bend in one direction only but not in the opposite direction and not in either lateral direction. In this embodiment, cuts can be made on one side of the outer tubing within, for example, the distal 10-cm of the tube length. Approximately 10 to 30 cuts can be generated with a width of approximately 0.001 to 0.015 inches. The cut depth, across the tube diameter from one side, can range between 0.01 and 0.9 of the tube's diameter. In an embodiment, the cut depth can be approximately 0.4 to 0.6 of the tube's diameter with a cut width of about 0.005 inches or less. A second cut can be generated on the opposite side of the tube wherein the second cut is approximately 0.005 inches or less. In an embodiment, the outer tube can be bent into an arc first and then have the slots generated such that when the tube is bent back toward the 0.005-inch wide cuts, the tube will have an approximately straight configuration even through each tube segment between the cuts is slightly arced or curved.
The steerable needle, in other embodiments, can comprise monitoring systems to measure, display, announce, record, or evaluate operating parameters of the steerable transseptal needle. In an embodiment, the steerable transseptal needle can comprise strain gauges to measure the force being applied by the user to bend the needle. A torque gauge can also be comprised by the system to measure torque being applied to the control knob or the torque being applied by the distal curvature movement. The strain gauge or torque gauge can be affixed within the hub or elsewhere within the steerable transseptal needle to measure compression or tension forces. This information can be displayed in the form of a readout device, such as a digital display of the force or torque. The number of turns can be counted and displayed by, for example, a Hall-Effect sensor, mechanical counter, or the like. In an embodiment, the force or toque can be correlated to the angle of deflection at the distal end, the number of turns applied to the control knob, or both. The readout can be digital or analog and can be affixed to the hub or can be wirelessly received and displayed on external equipment such as a smart phone, computer, tablet computer, panel display, or the like. The wireless technology can, for example, comprise Wi-Fi, Bluetooth®, or other standardized protocols. The human interface can, in other embodiments, comprise audible feedback such as a simple beep or tone, or it can be more sophisticated and provide information using language callouts such as force, turns, torque, or the like.
In operation, the procedure is to advance a steerable transseptal needle, with a tissue piercing stylet affixed in place, through a transseptal introducer that has already been placed. The steerable transseptal needle is articulated to generate the proper curve, as determined under fluoroscopic or ultrasound guidance. The steerable transseptal needle transseptal introducer assembly is withdrawn caudally out of the superior vena cava and into the right atrium of the heart. Proper location, orientation, tenting, and other features are confirmed. Radiopaque dye can be injected through the steerable transseptal needle to facilitate marking of the fossa ovalis or blood flow around the distal end of the steerable transseptal needle. Pressure measurements can also be taken through the lumen of the steerable transseptal needle to confirm tracings consistent with the right or left atrium of the heart. Once proper positioning has been confirmed, a safety is removed from the stylet hub and a button on the stylet hub is depressed or actuated to cause the sharpened stylet tip to advance out beyond the distal end of the steerable transseptal needle. This sharpened stylet punches through the fossa ovalis and the septal tissue pulls over the stylet, over the inner tube, and over the dilator of the transseptal introducer. At this point, the sharp stylet is released and retracts proximally within the steerable transseptal needle. The transseptal introducer is now within the left atrium of the heart and the steerable transseptal introducer can be withdrawn from the lumen of the dilator.
The side slot 310 communicates with the tip central lumen 320 and permits the cutting element 316 and its spring arm 318 to move radially outward beyond the central lumen 320, wherein it resides when at rest, biased by the spring arm 318. The cutting element 316 can be fabricated from stainless steel, nitinol, titanium, cobalt nickel alloy or the like.
In this embodiment, the endoluminal punch 334 can be inserted through the introducer 300 further comprising the dilator 304 which can further comprise the cutting apparatus 316 tipped with 314, which can project laterally to assist with cutting tissue surrounding the tapered tip of the dilator. The cutting apparatus can comprise a sharp blade like structure. The cutting apparatus can be spring loaded so that, when something is advanced through the internal lumen of the dilator, the blade is forced out of the way and projects laterally outward. This way, the lateral cutting blade is restricted inside the dilator partially or completely when nothing is inserted through the lumen. A segment of the lateral cutting blade can be dispositioned within the lumen 320 to facilitate outward advance of the cutting blade or apparatus when another object is forced through the lumen. This feature can be useful in penetrating tissue with the Steerable Endoluminal Punch and then following it with the larger diameter dilator and introducer or catheter. The laterally projecting blade or cutter can enlarge a hole in tissue already incised by the Endoluminal Punch, thus facilitating passage of the dilator and introducer through the hole in the tissue. Conditions can occur in patients who have had prior procedures and therefore incur scar tissue on the interatrial septum, for example, and this tissue is very difficult to cross. Further, it appears that patients who have been in long term persistent atrial fibrillation incur morphological changes to the myocardium in the interatrial septum, and perhaps other parts of the atrial tissue, that cause it to become tough to penetrate.
In other embodiments, the steerable endoluminal punch can comprise a blunted distal end with a slot at the end to allow a blade to project out the distal end of the steerable endoluminal punch. The blunted distal end can be retracted to expose the blade for cutting or the blade can be advanced out the distal end through the slot which would appear like the window of an observatory. The blade can be fixed or it can oscillate or rotate as described herein.
The ultrasonic driver 116 can operate in the subsonic range (less than about 1 Hz) all the way up through the ultrasonic range (5-50 kHz). Power levels in the range of about ½ Watt to about 20 Watts can be used with a preferred range of about 2 Watts to about 6 Watts. In the illustrated embodiment, the endoluminal punch is of the steerable variety wherein the control knob 110 can generate off-center forces at the tip to bend a region of outer tube 106 which is selectively made more bendable than the rest of the shaft. In the illustrated embodiment, the vibratory driver 116 is affixed to the hub 102 which is affixed to the anchor 130. The shaft 122 of the vibratory drive 116, which can comprise a hollow lumen (not shown) to allow for fluid transport therethrough, is affixed to the inner tube 104 such that the inner tube 104 is vibrated back and forth axially a small amount which is transmitted to the tip causing a generally axial but also sideways vibratory motion that can be used to promote tissue incision.
In these embodiments, the vibratory device 116 is directly or indirectly affixed to the anchor 130 of the inner tube 104, the anchor 130 in turn being affixed to the hub 102. The inner tube 104 is affixed to the shaft 122 of the vibratory device and moves therewith. Thus, the inner tube 104 is separated from the hub 102 by the vibratory structure 116. The vibratory mechanism 116 can comprise a loudspeaker type linear movement device, an off-center weight which is rotated about an axis by a motor, a piezoelectric driver, a pneumatic driver, or the like. These systems, in some embodiments, require an input comprising a sine wave structure, or other, which can be controlled in terms of amplitude and frequency and wave shape. In these embodiments, the anchor can be made to vibrate on axis, thus transmitting the vibrator energy to the distal tip of the device through the inner tube and control rod or rods at the distal portion of the steerable endoluminal punch. Since the inner tube is affixed to the outer tube in an off-center manner near the distal end of the steerable endoluminal punch, the distal end of the steerable endoluminal punch will operably vibrate in a lateral direction to the axis of the steerable endoluminal punch. This vibration (oscillatory) energy can provide assistance in cutting through tissue beyond that possible with a static device. The vibratory transducer can be operably connected to a power supply and controller by means of a cable to a power source external to the hub of the steerable endoluminal punch or the power supply can comprise batteries and signal conditioning apparatus and/or software within the steerable endoluminal punch hub. The frequency of vibration can range from less than 1 Hz to ultrasound frequencies of about 40-kHz or more.
In other embodiments, the vibratory apparatus can be affixed to, and operably connected to, a separate control rod or wire disposed within a lumen of the steerable endoluminal punch and routed from a driver at the proximal end to a point at or near the distal end of the steerable endoluminal punch. This control rod or wire can transmit the energy to the distal end of the steerable endoluminal punch wherein it can be used to drive lateral movement, axial movement, rotary movement, or a combination thereof to facilitate tissue penetration and crossing through a hole larger than that which can be made with the steerable endoluminal punch alone, without the energy assistance. The wire or control rod can be affixed to the distal end of the steerable endoluminal punch in an off-center way to generate lateral tip movement in an oscillatory fashion.
The coupler 236 connects the shaft 222 to the stopcock 120 and therefore the hub 102 of the steerable endoluminal punch. In this configuration, the energy is transmitted through the entire steerable endoluminal punch in an axial fashion but does not cause any relative movement between the inner 104 and outer 106 tubes.
The energized steerable endoluminal punch system 100 and 200 configurations can be used for tissue punch, incision, or penetration, apparatus, etc. They can, in other embodiments, comprise the structure of a guidewire, a stiff track over which other devices or catheters are advanced, an introducer, a catheter, a delivery catheter for an implant or fluids, a therapeutic catheter, a diagnostic catheter, a catheter to support other procedures, or the like. The steerable endoluminal punch can be monitored using fluoroscopy and radiopaque markers affixed or integral to the steerable endoluminal punch. It can also be monitored using ultrasound guidance such as with transesophageal echocardiography, intracardiac echocardiography, real-time three-dimensional echocardiography from transducers and systems affixed to the steerable endoluminal punch.
In other embodiments, vibration can be generated by an ultrasonic transducer mounted within the steerable endoluminal punch tubing. An ultrasonic wire can be disposed along the steerable endoluminal punch tubing through a lumen. An ultrasonic transducer can be affixed to the distal end of the steerable endoluminal punch.
Note that a stubby blunt stylet, expandable or non-expandable, can be used to shield the sharp pointed distal end of the endoluminal punch (steerable endoluminal punch) from skiving plastic off the wall of the introducer dilator or from getting dulled by the same interaction. It is generally beneficial to align the direction of curvatures of the endoluminal punch with that of the introducer and dilator.
The introducer sheath also comprises a proximal end (not shown) further comprising a hub, a hemostasis valve, a side port with a lead line and a stopcock. The introducer sheath tubing 402 can be preferentially reinforced with braided or coil structures fabricated from stainless steel, nitinol, polymeric materials, or the like. The introducer sheath tubing 402 further can comprise a radiopaque marker near its distal end fabricated from materials such as, but not limited to, barium sulfate, bismuth sulfate, tantalum, gold, platinum, platinum iridium, and the like.
The proximal end of the dilator comprises a hub (not shown), further comprising a keyed feature that determines endoluminal punch circumferential orientation. The keyed feature aligns any side projecting elements, including blades, etc., with the side projecting lumen 612 in the dilator shaft 604. The hub (not shown) is affixed to the dilator shaft 604 by adhesive, welding, over-molding or insert molding, swage connectors, and the like.
The side projecting lumen stop 618 can comprise an integral segment of tapered dilator shaft 604, which makes the slotted distal opening to the dilator shaft appear as a window rather than a continuous opening that breaks out in the distal end. The dilator shaft 604 can be reinforced or homogeneous in structure. The dilator shaft 604 should be flexible to varying degrees but comprise functional axial stiffness. The dilator shaft 604 can be extruded with the side projecting lumen integral to the dilator shaft and opening fully into the side of the main lumen 606. The tip 610 can be created or formed by secondary operations such as rf forming, induction forming, and the like. The region where the side projecting lumen 618 breaks through the tapered distal wall 610 can be generated with the mold used for the tip tapering 610 and stepdown 614 in the dilator.
In an embodiment for a standard transseptal introducer, the ID of the dilator main lumen can be approximately 0.055 to 0.065 inches. The diameter of the stepdown lumen can range from about 0.030 inches to about 0.038 inches, depending on the size of instruments intended to be placed therethrough. The stepdown 614 is located at a specific location relative to the distal end to accommodate standard endoluminal punches. The width of the side projecting lumen 612 can range from about 0.005 inches to 0.020 inches. The radial projection of the side projecting lumen 612 can vary to accept specific cutting instruments but in an embodiment can range from about 0.005 to 0.040 inches, depending also on the overall diameter of the dilator tubing.
Note that in the case of the devices shown in
Procedurally, this system with the side projecting cutting blade 804 or 822 has advantages in that large incisions can be made in tissue without the need for radiofrequency power, or the like. It is actuated the same way that current transseptal needles are actuated so there is no learning curve for users, although the effects are dramatic, especially in the case where the tissue is scarred, fibrosed, friable, or otherwise damaged. There is, furthermore, no need for a separate cutting mechanism built into the introducer to facilitate passage of the dilator and introducer sheath because the side projecting blade of the endoluminal punch handles this function.
Thus, as described in relation to
The punch preferably includes a distally facing shoulder formed at a distal end of the first segment, sized to be obstructed by a corresponding proximally facing shoulder in a dilator used to deliver the punch to limit distal translation of the punch distal tip.
The endoluminal punch is configured for use as part of an endoluminal punch system comprising a dilator and a sheath, with the dilator disposed within a lumen of the sheath. The dilator has a distal end and a proximal end and a dilator lumen extending from the proximal end to the distal end, and a channel open the lumen extending from the proximal end to the distal end of the dilator. The proximal segment and the distal segment of the endoluminal punch are configured to be slidably disposed within the dilator lumen, and the cutting blade is sized to be slidably disposed within the channel. Where the punch has a distally facing shoulder, the
The dilator lumen may be formed with a dilator lumen proximal segment and a dilator lumen distal segment, with the dilator lumen proximal segment having a first diameter and the dilator lumen distal segment having a second diameter smaller than the first diameter, such that the dilator lumen distal segment forms a proximally facing shoulder configured to abut the distally facing shoulder at the distal end of the first segment of the endoluminal punch.
The dilator distal segment is preferably formed with a tapered distal tip, and the channel preferably extends radially through the tapered distal tip, such that the cutting blade extends radially from the tapered distal tip when the distal segment of the endoluminal punch is disposed within the tapered distal tip. To limit distal translation of the cutting blade, a cutting blade stop disposed in a distal end of the channel, said cutting blade stop configured.
In the illustrated embodiments of
The orientation of the distal curves 916 and 922 can be random or they can be set by a key in the proximal end of the piercing stylet, e.g. hub, and a complimentary keyhole in the hub of the endoluminal punch, or it can be manually oriented using rotational landmarks on the two hubs. Alignment can be set vertically, as illustrated, sideways, or specifically toward the top or bottom of the endoluminal punch tip bevel, etc. In the illustrated embodiment, the blade curves 916 and 922 are offset so that they are pointed approximately oriented 180 degrees from the endoluminal punch point and facets. The cutting edges project sufficiently laterally so as to cut a clinically meaningful incision while being able to be inserted and removed from the endoluminal punch with ease. In the illustrated embodiment, the cutting edge offset is approximately 0.005 to 0.050 inches, or more, beyond the outside diameter of the inner tube 908 with a preferred extent of about 0.010 to 0.030 inches.
The distal curves 916 and 922 form cantilever springs to bias the cutting edges radially outward from the axis of the endoluminal punch. The cutting edges can also be biased using other spring configurations such as coil springs and the like. The distal curves 916 and 922, alone or including the entire piercing stylet wires 912 and 920 can be formed from nitinol and specifically shape memory nitinol so that they spring sideways only after exposure to body temperatures of about 34 to 40 degrees C. These wires can also be superelastic nitinol, cobalt nickel alloy, stainless steel, titanium, PEEK, and the like.
In practice, a piercing stylet or center punch is used when tissue is so difficult to penetrate that the endoluminal punch passes through the tissue but the dilator 904 and the sheath 902 cannot pass through the small incision. The sideways cut of the piercing stylet increases the size of the incision and allows the large diameter sheath and dilator to pass. In some cases, it is beneficial to withdraw an endoluminal punch within the dilator tip if the dilator cannot pass. The piercing stylet is next advanced and exposed distally before the endoluminal punch is exposed out the distal end of the dilator 904. Thus the curve sharp end of the piercing stylet contacts the tissue simultaneously or prior to that of the sharp end 910 of the endoluminal punch.
| Number | Date | Country | |
|---|---|---|---|
| 63118523 | Nov 2020 | US |
