Steerable endoluminal punch

Abstract

This invention is a transvascularly placed punch, further including internal steerability and the ability to articulate in a direction at right angles to its longitudinal axis at or near its distal end. The punch is generally fabricated from stainless steel and includes an outer tube, an intermediate tube, a central stylet, hub structures, and a distal articulating region. The punch can be advanced through a body lumen in its straight configuration and then be selectively articulated or curved to permit negotiation of tortuous curvature or to permit optimal approach or access to a puncture site. The punch is able to create holes in the atrial septum of the heart or other structures and is easier to use than punches that are pre-curved near their distal tip since it is easier to advance through accessory catheters.

Description

PRIORITY CLAIM [0001] This application claims priority benefit under 35 USC § 119(e) from U.S. Provisional Application No. 60 / 702,239, filed Jul. 25, 2005, entitled STEERABLE ENDOLUMINAL PUNCH, the entire contents of which are hereby incorporated herein by reference.FIELD OF THE INVENTION [0002] 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. BACKGROUND OF THE INVENTION [0003] During certain interventional procedures that are directed at cardiac access, the patient is catheterized through an access point in a vein or artery. A catheter is routed to the heart or other region of the cardiovascular system through the access point, which may be created by a cutdown or a percutaneous access procedure. The catheter may be routed to a target location within the heart, cerebrovasculature, or...

AI Technical Summary

Benefits of technology

[0011] In another embodiment, steerability can be obtained using actuators on the surface or within the interior of the cannula to force bending of the cannula. These actuators can be typically electrically powered. In an embodiment, an actuator can comprise electrical leads, a power source, a compressible substrate, and shape memory materials such as nitinol. Such actuators may be distributed along the length of the cannula. The actuators may be placed so as to oppose each other. Opposing actuators are activated one at a time and not simultaneously and can generate a steering effect or back and forth motion.

[0012] Other embodiments of the inventions comprise methods of use. One method of use involves inserting the central core wire so that it protrude out the distal end of the punch. A percutaneous or cutdown procedure is performed to gain access to the vasculature, either a vein or an artery. An introducer and guidewire are placed within the vasculature and the guidewire is routed proximate to the target treatment site. The introducer can be removed at this time. A guiding catheter, preferably with a central obturator or dilator is routed over the guidewire to the target site. In an embodiment, the target site can be the atrial septum. The guidewire can be removed at this time. The punch is adjusted so that it assumes a substantially straight configuration. The punch can be advanced through the central lumen of the already placed catheter. By making the punch as straight as possible, there is no curvature to force the sharpened distal edges of the punch to scrape the inside of the catheter lumen as the punch is advanced distally inside the guide catheter and potentially dislodge or scythe away debris or material which could cause embolic effects to the patient. Carefully ensuring that the punch does not protrude beyond the distal end of the catheter or its obturator, the punch is next deflected so that it forms a curve. The curve is oriented so that it is medially directed toward the atrial septum. Alignment with any curvature of the catheter can be completed at this time. The punch and guide catheter / obturator are withdrawn caudally, as a unit, into the right atrium. The punch and guide catheter are positioned using fluoroscopy or other imaging system against the Fossa Ovalis. The Fossa Ovalis is a relatively thin structure and the force of the punch will tent the Fossa Ovalis toward the left atrium. In one embodiment, the central core wire or stylet, initially advanced, can next be withdrawn to expose the sharp distal edge of the punch. When correctly positioned under fluoroscopy, ultrasound, or other imaging system, dye can be injected into the central lumen of the punch at its proximal end and be expelled out of the distal end of the punch and obturator to paint or mark the Fossa Ovalis. A generally “V-shaped” mark can be observed under fluoroscopy, which denotes the location of the Fossa Ovalis. The curvature of the punch can be increased or decreased by articulation to gain optimal alignment with the Fossa Ovalis. This steering function can be very beneficial in device placement.

Problems solved by technology

Erroneous placement of the punch can lead to penetration of adjacent structures such as the aorta, damage to which would cause potentially severe hemorrhage and potentially compromise the health of the patient.

A main disadvantage of this system is that the Brockenbrough needle system is pre-curved at its distal end and is relatively rigid.

The material carved from the guide catheter could potentially be released into the cardiovascular system and generate emboli with any number of serious clinical sequelae.

Furthermore, advancing a pre-curved, rigid punch through the cardiovascular system is difficult and could potentially damage the vessel wall or any number of significant cardiovascular structures, during the advancement.

During ex-vivo insertion, the debris can be flushed from the lumen of the guide catheter but complete removal is not assured and emboli can still be generated by the device.

However, if the guide catheter was already inserted into the cardiovascular system, the debris could not be flushed out ahead of time and could easily flow toward or be released into the cardiovascular system with potentially catastrophic or fatal results.

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